Made available in DSpace on 2016-06-02T19:22:01Z (GMT). No. of bitstreams: 1 1726.pdf: 1955854 bytes, checksum: 4645fc1da948f09f7ca3036b56ee7241 (MD5) Previous issue date: 2008-03-27 / Universidade Federal de Sao Carlos / Cardiovascular responses are integrated at different levels of the central nervous system (CNS). In the brainstem, there are different areas related to the cardiovascular control such as the rostral ventrolateral medulla (RVLM) that activates sympathetic pre-ganglionic neurons in the spinal cord (IML) inducing pressor response. Like glutamatergic activation, central cholinergic and angiotensinergic activation modulates sympathetic activity and increases arterial pressure. The RVLM receives inhibitory and excitatory projections from different areas of the central nervous system that are important to modulate cardiovascular responses. One of the areas that send projection to the RVLM is the anteroventral third ventricle (AV3V) region. AV3V lesion impairs many forms of hypertension and reduces pressor responses like those produced by central cholinergic and angiotensinergic activation. Recent study in unanesthetized rats has shown that the AV3V lesion attenuates the pressor response to glutamatergic activation into the RVLM. Besides glutamate, injections of angiotensin II (ANG II) or carbachol (cholinergic agonist) into the RVLM evoke increase in the sympathetic activity and blood pressure. For this reason, in the present study, we investigated the effects of acute (1 day) or chronic (15 days) AV3V lesions on pressor responses produced by ANG II (200 ng/100 nl) or carbachol (1 nmol/100 nl) into the RVLM. Male Holtzman rats (280 a 320 g) with sham or electrolytic AV3V lesions and a stainless steel cannula implanted into the RVLM were used. Mean arterial pressure (MAP) and heart rate (HR) were recorded in unanesthetized rats that had polyethylene tubing (PE 10) implanted into the abdominal aorta through the femoral artery on day before the experiments. A second polyethylene tubing was inserted in the femoral vein for baroreflex and chemoreflex tests. Central injections were made using 5 ml Hamilton syringes. The volume of the central injections into the RVLM was 100 nl. The results have shown that both acute and chronic AV3V lesion attenuate the pressor responses to ANG II (12 ± 3 and 12 ± 5 vs. control: 26 ± 4 mmHg) but not the pressor responses to carbachol (38 ± 4 and 29 ± 3 vs. control: 34 ± 4 mmHg) suggesting that some mechanisms belonging to the RVLM are affected and other are not affected by AV3V lesions. Besides, AV3V lesion does not alter baro and chemoreflex responses produced by endovenous (i.v) injections of phenylephrine, sodium nitroprusside and potassium cyanide. After these results, another question arose: which would be the possible mechanisms impaired by the AV3V lesion that attenuate the pressor responses to RVLM activation? The AV3V region is important for the activation of pressor mechanism like sympathetic activity and vasopressin secretion produced by central cholinergic and angiotensinergic activation. Therefore, the pressor response to glutamate into the RVLM was tested in rats with central cholinergic blockade produced by the injection of atropine (4 nmol/1 ml) or angiotensinergic blockade produced by injection of losartan (100 mg/1 ml) or ZD 7155 (50 mg/1 ml) into the lateral ventricle (LV). Male Holtzman rats with stainless steel cannula implanted into the LV and unilaterally into the RVLM were used. MAP and HR were recorded in unanesthetized rats with polyetylene tubing inserted into the abdominal aorta through the femoral artery and vein. The volume of the central injections into the LV was 1 ml. The results showed that the pressor response to glutamate injected into the RVLM (51 ± 4 mmHg) in control condition was attenuated after injection of atropine (36 ± 5 mmHg), losartan (22 ± 5 mmHg) or ZD 7155 (26 ± 7 mmHg) into the LV. However, a question that remained was about the possible spreading of these antagonists into the brain blocking the receptors directly into the RVLM. For this reason, we tested the pressor responses to glutamate into the RVLM after cholinergic or angiotensinergic blockade into the own RVLM. Mean arterial pressure (MAP) and heart rate (HR) were recorded in unanesthetized rats with cannula only into the RVLM and polyethylene tubing implanted into the abdominal aorta through the femoral artery. The results showed that atropine (4 nmol/100 nl) injected into the RVLM did not alter the pressor response to glutamate into the same site (49± 4 vs. control: 50 ± 4 mmHg). So, only cholinergic mechanisms belonging to forebrain or areas outside the RVLM are important for the pressor response to glutamate into the RVLM. However, the pressor response to glutamate into the RVLM was almost abolished and attenuated after injection of the losartan (5 ± 3 mmHg) or ZD 7155 (33 ± 4 mmHg), respectively, into the RVLM, which did not solve the question about the possible spread of losartan or ZD 7155. With the same purpose we tested the pressor response to ANG II into the RVLM after losartan or ZD 7155 into the LV. In this experiment, the pressor response to ANG II into the RVLM in control condition (26 ± 3 mmHg) was not impaired after losartan or ZD 7155 into the LV (20 ± 3 e 23 ± 1 mmHg, respectively) suggesting that these antagonists injected into the LV do not reach the RVLM. Therefore, angiotensinergic mechanisms belonging in the RVLM or from outside the RVLM (probably forebrain) are important for the pressor response to glutamate into the RVLM. However, it is important to consider that AV3V lesion reduces the pressor response to ANG II into the RVLM, while icv injection of the angiotensinergic antagonists showed no effect in this response, which suggests that the effects of AV3V lesion reducing the pressor response to ANG II into the RVLM are not related to any impairment of forebrain angiotensinergic mechanisms by the lesion. Another aim was to study if glutamatergic receptor activation in the RVLM was necessary for the pressor response to central cholinergic or angiotensinergic activation. For this, male Holtzman rats with stainless steel cannulas implanted into the LV and bilaterally into the RVLM were used. The results showed no difference between the cardiovascular responses produced by carbachol into the LV after kynurenic acid (1 nmol/100 nl) bilaterally into the RVLM (36 ± 1 mmHg and 22 ± 10 bpm) when compared with control condition (39 ± 2 mmHg and 23 ± 14 bpm). Also, there was not difference between the cardiovascular responses produced by ANG II into the LV after kynurenic acid (1 nmol/100 nl) into the RVLM (28 ± 3 mmHg and 10 ± 13 bpm) when compared with control condition (26 ± 2 mmHg and -12 ± 5 bpm). This dose of kynurenic acid almost abolished the pressor response to glutamate (2 nmol/100 nl) injected into the RVLM but not the cardiovascular reflexes produced by baro and chemoreflex activation. Therefore, the pressor response to forebrain cholinergic or angiotensinergic activation does not depend on glutamatergic synapses in the RVLM. Besides, the results also showed that the pressor response to chemoreflex activation does not depend on release of glutamate into the RVLM / Respostas cardiovasculares podem ser integradas em diferentes níveis do sistema nervoso central (SNC). No bulbo existem várias áreas importantes para o controle cardiovascular e dentre elas o principal sítio de ativação dos neurônios pré-ganglionares simpáticos para a coluna intermédio lateral (CIL), a área rostroventrolateral (RVL) cuja ativação glutamatérgica provoca resposta pressora. Semelhante à ativação glutamatérgica, também a ativação de receptores colinérgicos e angiotensinérgicos em diferentes áreas centrais incluindo a área RVL provoca aumento na pressão arterial, colaborando para a manutenção da atividade simpática. Projeções inibitórias e excitatórias direcionadas à área RVL garantem uma sintonia fina dos parâmetros cardiovasculares e dentre essas projeções destacam-se aquelas que se originam em áreas hipotalâmicas como a região anteroventral do terceiro ventrículo (AV3V), cuja lesão impede o desenvolvimento de diversas formas de hipertensão experimental em animais e reduz vários tipos de respostas pressoras como, por exemplo, induzida pela ativação angiotensinérgica e colinérgica central. Em estudo recente demonstramos que a lesão da região AV3V atenua a resposta pressora à ativação glutamatérgica da área RVL em ratos não anestesiados. Sabendo-se que a exemplo do glutamato, injeções de angiotensina II (ANG II) ou carbacol (agonista colinérgico muscarínico) na área RVL produzem respostas pressoras, no presente estudo investigamos os efeitos de lesões agudas (1 dia) ou crônicas (15 dias) da região AV3V nas respostas pressoras produzidas pela injeção de ANG II (200 ng/100 nl) ou carbacol (1 nmol/100 nl) na área RVL de ratos não anestesiados. Para isso foram utilizados ratos Holtzman (280 a 320 g) com lesão eletrolítica ou lesão fictícia da região AV3V aguda ou crônica e com cânulas de aço inoxidável implantadas na área RVL. A pressão arterial média (PAM) e a frequência cardíaca (FC) foram registradas em ratos não anestesiados que tiveram a artéria femoral canulada com tubo de polietileno (PE 10) no dia anterior ao do registro. A veia femoral também foi canulada para injeções das drogas endovenosas (i.v) para os testes de baro e quimiorreflexo. As injeções na área RVL foram feitas em um volume de 100 nl com auxílio de uma seringa Hamilton de 5 ml. Os resultados mostraram que tanto a lesão eletrolítica aguda quanto a crônica da região AV3V atenuaram as respostas pressoras da ANG II (12 ± 3 e 12 ± 5 vs. controle: 26 ± 4 mmHg) mas não as respostas pressoras do carbacol (38 ± 4 e 29 ± 3 vs. controle: 34 ± 4 mmHg) sugerindo que alguns mecanismos pressores presentes na área RVL não são influenciados pela lesão da região AV3V. Além disso, a lesão da região AV3V não alterou os reflexos cardiovasculares como o barorreflexo induzido pelas injeções i.v de fenilefrina e nitroprussiato de sódio e o quimiorreflexo induzido pelo cianeto de potássio (KCN) i.v. Visto que a integridade da região AV3V é importante para algumas respostas pressoras causadas pela ativação da área RVL, como por exemplo, glutamatérgica e angiotensinérgica, uma questão que surgiu foi quais seriam os possíveis mecanismos que atuariam facilitando o aparecimento dessas respostas pressoras e que prejudicados pela lesão, diminuiriam sua atividade e consequentemente essas respostas pressoras. Sabendo-se que a região AV3V é importante para a ativação de mecanismos pressores como aumento da atividade simpática e secreção de vasopressina produzidas pela ativação de receptores colinérgicos e angiotensinérgicos centrais, foi testada a resposta pressora do glutamato injetado na área RVL frente ao bloqueio colinérgico central com injeção de atropina (4 nmol/1 ml) ou angiotensinérgico central com injeção de losartan (100 mg/1 ml) ou ZD 7155 (50 mg/1 ml) no ventrículo lateral (VL). Para isso foram utilizados ratos com cânulas implantas tanto no VL, para as injeções dos antagonistas colinérgico ou angiotensinérgicos e unilateralmente na área RVL para a injeção do glutamato. A PAM e a FC foram registradas em ratos não anestesiados que tiveram um dia antes dos experimentos a canulação da artéria e veia femoral. O volume das injeções no VL foram sempre de 1 ml. Os resultados demonstram que a resposta pressora do glutamato injetado na área RVL (51 ± 4 mmHg) em condição controle foi atenuada após a injeção de atropina (36 ± 5 mmHg), losartan (22 ± 5 mmHg) ou ZD 7155 (26 ± 7 mmHg) no VL. Porém, como os antagonistas foram injetados no VL, uma dúvida que surgiu foi sobre um possível espalhamento dos mesmos atuando nos receptores presentes na área RVL. Por essa razão, houve a necessidade de testarmos a resposta pressora do glutamato na área RVL depois do bloqueio colinérgico ou angiotensinérgico na própria área RVL. A PAM e FC foram registradas em ratos não anestesiados, implantados com cânulas unilaterais na área RVL e que tiveram canulação da artéria femoral um dia antes dos experimentos. Os resultados mostraram que a injeção de atropina (4 nmol/100 nl) na área RVL não alterou a resposta pressora do glutamato na mesma área (49± 4 vs. controle: 50 ± 4 mmHg) indicando nesse caso que apenas os mecanismos colinérgicos presentes no prosencéfalo são importantes para a resposta pressora do glutamato na área RVL. No entanto, a resposta pressora do glutamato na área RVL foi praticamente abolida e atenuada depois do bloqueio angiotensinérgico com injeção de losartan (5 ± 3 mmHg) ou ZD 7155 (33 ± 4 mmHg), respectivamente na própria área RVL. Por isso, um novo experimento foi realizado e nele verificou-se que a resposta pressora da ANG II injetada na área RVL em condição controle (26 ± 3 mmHg) não foi diferente daquela observada depois da injeção do losartan ou ZD 7155 no VL (20 ± 3 e 23 ± 1 mmHg, respectivamente) o que sugere que ambos antagonistas losartan e ZD 7155 injetados no VL nas doses utilizadas não estariam atuando diretamente na área RVL. Dessa forma, pode-se sugerir que mecanismos angiotensinérgicos presentes no prosencéfalo ou na área RVL são importantes para as respostas do glutamato na área RVL. Porém, com esses resultados ainda não podemos concluir se a lesão da região AV3V atenua as respostas pressoras produzidas pela ANG II na área RVL prejudicando os mesmos mecanismos centrais bloqueados pelos antagonistas injetados no VL, pois a resposta pressora da ANG II foi atenuada pela lesão da região AV3V, mas não pelos bloqueios farmacológicos centrais. Outro objetivo foi estudar se a ativação de receptores glutamatérgicos presentes na área RVL seria importante para a resposta pressora produzida pela ativação colinérgica ou angiotensinérgica central. Para tanto, utilizamos ratos com cânulas implantadas bilateralmente na área RVL e no VL. Os resultados demonstraram que depois da injeção do antagonista de receptores glutamatérgicos ácido quinurênico (1 nmol/100 nl) bilateralmente na área RVL não houve diferenças nas respostas cardiovasculares produzidas pela injeção de carbacol (36 ± 1 mmHg e 22 ± 10 bpm vs. controle: 39 ± 2 mmHg e 23 ± 14 bpm) e ANG II (28 ± 3 mmHg e 10 ± 13 bpm vs. controle: 26 ± 2 mmHg e -12 ± 5 bpm) no VL. Essa dose de ácido quinurênico praticamente bloqueou a resposta pressora do glutamato (2 nmol/100 nl) na área RVL, porém não alterou os reflexos cardiovasculares como barorreflexo e quimiorreflexo. Assim, sugere-se que a resposta pressora produzida pelo aumento da atividade colinérgica ou angiotensinérgica de áreas prosencefálicas não depende de sinapses glutamatérgicas na área RVL. Além disso, os resultados também sugerem que a resposta pressora do quimiorreflexo não depende da liberação de glutamato na área RVL

Made available in DSpace on 2016-06-02T19:22:09Z (GMT). No. of bitstreams: 1 5326.pdf: 3132298 bytes, checksum: b48fee8c0ed5cf0a98acd523a57a6a84 (MD5) Previous issue date: 2013-06-28 / Universidade Federal de Minas Gerais / The rostroventrolateral medulla (RVLM) is a main central area of origin of sympathetic premotor neurons in the central nervous system (CNS) and has an important role in the generation and maintenance of sympathetic vasomotor tone. The RVLM receives both excitatory and inhibitory influences from different regions of the CNS. Recent results from our laboratory suggest that the activity of forebrain cholinergic and angiotensinergic mechanisms and anteroventral region of the third ventricle (AV3V) is important for the pressor response produced by injection of the excitatory amino acid glutamate in the RVLM. Intracerebroventricular (icv) injection of carbachol (cholinergic agonist) or angiotensin II (ANG II) causes pressor responses dependent on sympathetic activation and vasopressin secretion that are abolished by lesions of the AV3V region. Studies in anesthetized rats suggested that changes in fluid-electrolyte balance, particularly in rats with access to only normal chow and 0.9% NaCl for 14 days, increases sympathetic activity and blood pressure in response to injections of glutamate into the RVLM. In the present study, we investigated the cardiovascular responses produced by injection of glutamate, acetylcholine, GABA and angiotensin II in the RVLM in unanesthetized rats after 24 h water deprivation or access to only normal chow and 0.9% NaCl for 14 days. In this last protocol it was also tested the effects of different doses of glutamate (0.1, 1, 3 and 5 nmol/100 nl) injected into the RVLM. Basal mean arterial pressure (MAP) and heart rate (HR) in rats with 24 h of water deprivation (108 +- 2 mmHg and 354 +- 17 bpm, respectively) or rats treated with normal chow and 0.9% NaCl for 14 days (115 +- 2 mmHg and 359 +- 17 bpm, respectively) were not different from those of control animals (113 +- 2 mmHg and 383 +- 16 bpm, respectively). Changes in MAP of animals with 24 h water deprivation were not different from those observed in control animals after injection into the RVLM of glutamate (5 nmol/100 nl) (51 +- 3 mmHg, vs. controls: 55 +- 4 mmHg), acetylcholine (10 nmol/100 nl) (22 +- 9 mmHg, vs. controls: 15 +- 12 mmHg), angiotensin II (200 ng/100 nl) (41 +- 5 mmHg, vs. controls: 50 +- 6 mmHg) or GABA (1 nmol/100 nl) (-19 +- 3 mmHg, vs. controls: -19 +- 3 mmHg). In animals that had access to 0.9% NaCl for 14 days, the changes in MAP were also similar to control animals after injection into the RVLM of glutamate (42 +- 7 mmHg, vs. controls: 46 +- 16 mmHg), acetylcholine (31 +- 3 mmHg, vs. controls: 26 +- 2 mmHg), angiotensin II (53 +- 4 mmHg, vs. controls: 46 +- 8 mmHg) or GABA (-22 +- 5 mmHg vs. controls: -17 +- 4 mmHg). In rats with access to 0.9% NaCl for 14 days we did not observe differences in the changes in MAP produced by injection of glutamate into the RVLM at doses of 0.1 nmol/100 nl (11 +- 1 mmHg, vs. controls: 10 +- 4 mmHg), 1 nmol/100 nl (17 +- 6 mmHg, vs. controls: 14 +- 4 mmHg), 3 nmol/100 nl (24 +- 9 mmHg, vs. controls: 43 +- 11 mmHg) or 5 nmol/100 nl (43 +- 6 mmHg, vs. controls: 56 +- 6 mmHg). The HR variations produced by the different treatments in the RVLM in control rats, rats with 24 h of water deprivation or those that had access to 0.9% NaCl for 14 days were also similar. Unlike the results in the literature with anesthetized rats, the present results suggest that the access to normal chow and 0.9% NaCl for 14 days does not modify the cardiovascular responses produced by the injection of different doses of glutamate, acetylcholine, ANG II or GABA into the RVLM in unanesthetized rats. The same is true for unanesthetized rats with 24 h water deprivation. Another objective of this study was to investigate the cardiovascular responses produced by injection of glutamate into the RVLM in awake rats pretreated with either carbachol (cholinergic agonist) or ANG II injected into the lateral ventricle (LV). Basal MAP and HR of the animals were 117 +- 4 mmHg and 400 +- 17 bpm, respectively. The pressor response produced by injection of glutamate (5 nmol/100 nl) into the RVLM increased after pretreatment with carbachol (4 nmol/1 £gl) or Ang II (50 ng/1 £gl) injected icv (59 +- 3 and 68 +- 5 mmHg, respectively) compared with the control responses produced by glutamate injection in the RVLM combined with icv injection of vehicle (37 +- 3 mmHg). The pressor responses produced by the injection of carbachol or ANG II icv (which reached a maximum of 56 +- 3 and 44 +- 3 mmHg, respectively) were already reduced (9 +- 2 and 6 +- 3 mmHg, respectively) at the time of injection glutamate into the RVLM (20 min after icv injection). There was no difference in the changes in HR that occurred after the injection of carbachol or ANG II into the LV or glutamate injected into the RVLM alone or combined. These results suggest that central cholinergic or angiotensinergic activation facilitates the pressor response produced by RVLM glutamatergic activation. Moxonidine (£\2 adrenergic/imidazole receptor agonist), used as antihypertensive, reduces sympathetic discharges by central action. Thus, we investigated the effect of previous injection of moxonidine into the RVLM on the cardiovascular responses produced by glutamate injection in the same area. Basal MAP and HR of the animals were 112 +- 4 mmHg and 393 +- 30 bpm, respectively. The previous injection of moxonidine (5 nmol/100 nl) into the RVLM reduced the pressor response produced by the injection of glutamate (5 nmol/100 nl) into the RVLM (23 +- 3 mmHg, vs. after vehicle: 45 +- 6 mmHg) without significant changes in the bradycardic response (-7 +- 18 bpm, vs. after vehicle: -28 +- 15 bpm). The results suggest that activation of £\2 adrenergic/imidazole receptors by the injection of moxonidine into the RVLM attenuates the pressor response resulting from sympathetic activation produced by glutamatergic stimulation of this area. Finally we investigated the cardiovascular responses produced by the injection of carbachol into the LV in rats treated with moxonidine injected bilaterally into the RVLM combined or not with vasopressinergic antagonist (AVP) injected intravenously (iv). Baseline MAP and HR of the animals that were treated with carbachol in the LV combination or not with the antagonist of AVP iv + moxonidine into the RVLM were 118 +- 3 mmHg and 404 +- 12 bpm, respectively. Bilateral injections of moxonidine (5 nmol/100 nl) into the RVLM in these rats caused a reduction in MAP when compared with the pre-injection values or controls. HR reduction was also observed after injections of moxonidine into the RVLM when compared to control. Previous injections of moxonidine (5 nmol/100 nl) into the RVLM reduced the initial pressor response (2 minutes) produced by the injection of carbachol (4 nmol/1 £gl) into the LV (21 +- 4 mmHg, vs. vehicle 40 +- 2 mmHg), whereas later (8 to 18 min after the injection of carbachol) occurred a potentiation of the pressor response to carbachol (63 +- 4 mmHg, vs. vehicle 44 +- 2 mmHg). The prior iv injection of the vasopressin V1 receptor antagonist (10 mg/kg body weight) reduced the late pressor response (8 to 18 min) produced by the injection of carbachol (4 nmol/1 £gl) in the rats treated with LV injections of moxonidine (5 nmol/100 nl) into the RVLM (8': 22 +- 3 mmHg; 10': 19 +- 3 mmHg; 12': 18 +- 3 mmHg; 14': 18 +- 3 mmHg; 16': 14 +- 3 mmHg; 18': 12 +- 3 mmHg) or vehicle treated in RVLM (8': 20 +- 3 mmHg; 10': 16 +- 3 mmHg; 12': 14 +- 3 mmHg; 14': 13 +- 3 mmHg; 16': 12 +- 3 mmHg; 18': 12 +- 3 mmHg). In rats treated with AVP antagonist the initial pressor response (2 minutes) was also reduced in the groups receiving moxonidine in the RVLM (17 +- 3 mmHg) or vehicle in RVLM the (29 +- 4 mmHg). There was no difference in the late response to carbachol of rats receiving injections of vehicle or moxonidine into the RVLM combined with vasopressin antagonist iv. The HR changes that occurred after the injection of carbachol into the LV combined with moxonidine or vehicle injected into the RVLM in rats receiving or not vasopressin antagonist iv were similar. The peak pressor response to carbachol injected into the LV of rats treated with moxonidine injected into the RVLM which was higher (63 +- 4 mm Hg) than that of vehicle-treated rats in RVLM (43 +- 2 mmHg) was reduced to similar values in rats with blockade of vasopressin V1 receptor treated with moxonidine (26 +- 2 mmHg) or vehicle in RVLM (32 +- 2 mmHg). Thus, the present results suggest that the late increase in the pressor response produced by injections of carbachol icv in rats treated with moxonidine in RVLM is due to increased secretion of vasopressin. / A região rostroventrolateral do bulbo (RVL) é um dos principais locais de origem de neurônios pré-motores simpáticos no sistema nervoso central (SNC) e tem uma importante participação na geração e manutenção do tônus vasomotor simpático. A região RVL recebe influências tanto excitatórias quanto inibitórias de diferentes regiões do SNC. Resultados recentes de nosso laboratório sugerem que a atividade de mecanismos angiotensinérgicos e colinérgicos prosencefálicos e da região anteroventral do terceiro ventrículo (AV3V) é importante para a resposta pressora produzida pela injeção do aminoácido excitatório glutamato na região RVL. Injeções intracerebroventriculares (icv) de carbacol (agonista colinérgico) ou angiotensina II (ANG II) causam respostas pressoras dependentes da ativação simpática e secreção de vasopressina que são abolidas pela lesão da região AV3V. Estudos em ratos anestesiados sugerem que modificações do equilíbrio hidroeletrolítico, particularmente em ratos com acesso apenas a ração normal e NaCl 0,9% por 14 dias, resultam em aumento da atividade simpática e da pressão arterial após injeções de glutamato na área RVL. No presente estudo, investigamos as respostas cardiovasculares produzidas por injeção de glutamato, acetilcolina, angiotensina II ou GABA na área RVL em ratos acordados após 24 h de privação hídrica ou do acesso apenas a ração normal e NaCl 0,9% durante 14 dias e neste último também foram testadas as respostas a diferentes doses de glutamato (0,1; 1; 3 e 5 nmol/100 nl) injetadas na área RVL. A PAM e a FC basais dos animais com privação hídrica (108 +- 2 mmHg e 354 +- 17 bpm, respectivamente) ou dos ratos tratados com ração normal e NaCl 0,9% durante 14 dias (115 +- 2 mmHg e 359 +- 17 bpm, respectivamente) não foram diferentes daquelas dos animais controles (113 +- 2 mmHg e 383 +- 16 bpm, respectivamente). As variações da PAM dos animais com 24 h de privação hídrica não foram diferentes das observadas nos animais controles após injeção na área RVL de glutamato (5 nmol/100 nl) (51 +- 3 mmHg, vs. controles: 55 +- 4 mmHg), acetilcolina (10 nmol/100 nl) (22 +- 9 mmHg, vs. controles: 15 +- 12 mmHg), angiotensina II (200 ng/100 nl) (41 +- 5 mmHg, vs. controles: 50 +- 6 mmHg) ou GABA (1 nmol/100 nl) (-19 +- 3 mmHg, vs. controles: -19 +- 3 mmHg). Nos animais que tiveram acesso a NaCl 0,9% por 14 dias, as alterações da PAM também foram similares às dos animais controles após injeção na área RVL de glutamato (42 +- 7 mmHg, vs. controles: 46 +- 16 mmHg), acetilcolina (31 +- 3 mmHg, vs. controles: 26 +- 2 mmHg), angiotensina II (53 +- 4 mmHg, vs. controles: 46 +- 8 mmHg) ou GABA (-22 +- 5 mmHg, vs. controles: -17 +- 4 mmHg). Em ratos com acesso a NaCl 0,9% por 14 dias também não foram observadas diferenças nas alterações da PAM produzidas pela injeção de glutamato na área RVL nas doses de 0,1 nmol/100 nl (11 +- 1 mmHg, vs. controles: 10 +- 4 mmHg), 1 nmol/100 nl (17 +- 6 mmHg, vs. controles: 14 +- 4 mmHg), 3 nmol/100 nl (24 +- 9 mmHg, vs. controles: 43 +- 11 mmHg) ou 5 nmol/100 nl (43 +- 6 mmHg, vs. controles: 56 +- 6 mmHg). As variações de FC produzidas pelos diferentes tratamentos na área RVL em ratos controles, com 24 de privação hídrica ou que tiveram acesso a NaCl 0,9% por 14 dias também foram semelhantes. Diferentemente do que sugerem resultados da literatura obtidos em ratos anestesiados, os presentes resultados sugerem que o acesso apenas a ração normal e NaCl 0,9% por 14 dias não modifica as respostas cardiovasculares produzidas pela injeção de diferentes doses de glutamato, acetilcolina, ANG II ou GABA na área RVL em ratos acordados. O mesmo é válido para ratos acordados com 24 h de privação hídrica. Outro objetivo deste estudo foi Investigar as respostas cardiovasculares produzidas pela injeção de glutamato na área RVL em ratos acordados pré-tratados com carbacol (agonista colinérgico) ou angiotensina II (ANG II) injetados no ventrículo lateral (LV). A PAM e a FC basais dos animais foram 117 +- 4 mmHg e 400 +- 17 bpm, respectivamente. A resposta pressora produzida pela injeção de glutamato (5 nmol/100 nl) na área RVL aumentou após o pré-tratamento com carbacol (4 nmol/1 μl) ou ANG II (50 ng/1 μl) injetados intracerebroventricularmente (icv) (59 +- 3 e 68 +- 5 mmHg, respectivamente) em comparação com as respostas controles produzidas pela injeção de glutamato na área RVL combinada com injeção de veículo icv (37 +- 3 mmHg). As respostas pressoras produzidas pela injeção de carbacol ou ANG II icv (que alcançaram o máximo de 56 ± 3 e 44 ± 3 mmHg, respectivamente) já se encontravam reduzidas (9 ± 2 e 6 ± 3 mmHg, respectivamente) no momento da injeção de glutamato na área RVL (20 min após a injeção icv). Não houve diferença nas modificações de FC que ocorreram após a injeção de carbacol ou ANG II no VL ou glutamato injetado na área RVL sozinhos ou combinados. Estes resultados sugerem que a ativação colinérgica ou angiotensinérgica central facilita a resposta pressora produzida pela ativação glutamatérgica da área RVL. A moxonidina (agonista de receptores adrenérgicos α2/imidazólicos), usada como anti-hipertensivo, reduz descargas simpáticas por ação central. Assim, foram investigados os efeitos de injeções prévias de moxonidina na área RVL sobre as respostas cardiovasculares produzidas por injeções de glutamato na mesma área. A PAM e a FC basais dos animais foram 112 +- 4 mmHg e 393 +- 30 bpm, respectivamente. A injeção prévia de moxonidina (5 nmol/100 nl) reduziu a resposta pressora produzida pela injeção de glutamato (5 nmol/100 nl) na área RVL (23 +- 3 mmHg, vs. após veículo: 45 +- 6 mmHg), sem modificações significantes da bradicardia (-7 +- 18 bpm, vs. após veículo: -28 +- 15 bpm). Os resultados sugerem que a ativação de receptores adrenérgico +-2 e/ou imidazólicos pela injeção de moxonidina na área RVL atenua a resposta pressora que resulta da ativação simpática produzida pela estimulação glutamatérgica desta área. Por último foram investigadas as respostas cardiovasculares produzidas pela injeção de carbacol no VL de ratos tratados com moxonidina injetada bilateralmente na área RVL combinada ou não com antagonista vasopressinérgico injetado intravenosamente (iv). A PAM e a FC basais dos animais que foram tratados com carbacol no VL combinado ou não com o antagonista de AVP iv + moxonidina na área RVL foram 118 +- 3 mmHg e 404 +- 12 bpm, respectivamente. As injeções bilaterais de moxonidina (5 nmol/100 nl) na área RVL também nestes ratos causaram redução da PAM quando comparado com o valor pré-injeção ou aos valores controles. Em relação à frequência cardíaca foi observada redução após as injeções de moxonidina da área RVL apenas quando comparados ao controle. As injeções prévias de moxonidina (5 nmol/100 nl) na área RVL reduziram a resposta pressora inicial (2 minutos) produzida pela injeção de carbacol (4 nmol/1 μl) no VL (21 +- 4 mmHg, vs. veículo: 40 +- 2 mmHg), enquanto que mais tardiamente (de 8 a 18 min após a injeção de carbacol) levou a uma potenciação da resposta pressora do carbacol (63 +- 4 mmHg, vs. veículo: 44 +- 2 mmHg). A injeção iv prévia do antagonista de receptores V1 de vasopressina (10 μg/kg de peso corporal) reduziu a resposta pressora tardia (de 8 a 18 min) produzida pela injeção de carbacol (4 nmol/1 μl) no VL em ratos tratados com injeções de moxonidina (5 nmol/100 nl) na área RVL (8 : 22 +- 3 mmHg; 10 : 19 +- 3 mmHg; 12 : 18 +- 3 mmHg; 14 : 18 +- 3 mmHg; 16 : 14 +- 3 mmHg; 18 : 12 +- 3 mmHg) ou tratados com veículo na área RVL (8 : 20 +- 3 mmHg; 10 : 16 +- 3 mmHg; 12 : 14 +- 3 mmHg; 14 : 13 +- 3 mmHg; 16 : 12 +- 3 mmHg; 18 : 12 +- 3 mmHg). Nos ratos tratados com antagonista de AVP também ocorreu redução da resposta pressora inicial (2 minutos) nos grupos que receberam moxonidina na área RVL (17 +- 3 mmHg) ou veículo na área RVL (29 ± 4 mmHg). Não houve diferença na resposta tardia do carbacol entre ratos que receberam injeção de veículo ou moxonidina na área RVL combinada com antagonista de vasopressina iv. As modificações de frequência cardíaca que ocorreram após a injeção de carbacol no VL combinada com moxonidina ou veículo injetado na área RVL em ratos que receberam ou não antagonista de vasopressina iv foram semelhantes. O pico da resposta pressora do carbacol injetado no VL em ratos tratados com moxonidina na área RVL que foi maior (63 +- 4 mmHg) do que aquele dos ratos tratados com veículo na área RVL (43 +- 2 mmHg), foi reduzido para valores semelhantes em ratos com bloqueio dos receptores V1 de vasopressina tratados com moxonidina (26 +- 2 mmHg) ou veículo na área RVL (32 +- 2 mmHg). Assim, os presentes resultados sugerem que o aumento tardio da resposta pressora produzida por injeções de carbacol icv em ratos tratados com moxonidina na área RVL é devido ao aumento da secreção de vasopressina.

Made available in DSpace on 2016-06-02T19:23:00Z (GMT). No. of bitstreams: 1 DissAAV.pdf: 1362349 bytes, checksum: 68cba4c2d130812fd38174505062b5a0 (MD5) Previous issue date: 2005-03-21 / Universidade Federal de Sao Carlos / Cardiovascular responses are integrated at different levels of the central nervous system (CNS). Particularly the hypothalamus and brainstem areas are involved in the control of autonomic responses and among them the cardiovascular responses. Different areas in the brainstem, like the nucleus tract solitarii (NTS), the rostroventrolateral medulla (RVLM), caudoventrolateral medulla (CVLM) and the nucleus ambigus are important to cardiovascular control. These areas of the brainstem that control the cardiovascular system receive information from receptors present in different parts of the body, specially the pressoreceptors and chemoreceptores and control the activity of the autonomic efferents. Injection of the excitatory amino acid glutamate into the NTS in anesthetized rats produces depressor response and bradycardia like barorreflex activation. Differently, in unanesthetized rats, injection of the glutamate into the NTS produces pressor response and bradycardia, similar to chemoreflex activation. The neuropeptide substance P may act as neurotransmitter or neuromodulator of differents cardiovascular reflexes and when injected into the NTS produces pressor response. The RVLM is the main site of sympathetic output to the intermediolateral cell column of the spinal cord. Injection of glutamate into the RVLM increases sympathetic activity and induces pressor response. Hypotalamic areas are also involved in the control of cardiovascular responses. For example, electrolytic lesions in the paraventricular nucleus of the hypothalamus (PVN), reduce the pressor response to chemoreflex activation with potassium cyanide (KCN) iv Another hypothalamic area important for cardiovascular control is the anteroventral third ventricle (AV3V) region. Electrolytic lesion of the AV3V region reduces the cardiovascular responses produced by central colinergic and angiotensinergic activation and abolish many forms of the experimental hypertension in animals. In the present study, in unanesthetized rats, we investigated the effects of acute (1 day) and cronic (15 days) AV3V lesions in the pressor responses produced by NTS activation with injection of the excitatory amino acid glutamate and substance P or injection of glutamate into the RVLM. The responses to activation of the baroreflex and chemoreflex were also tested. Rats with sham or electrolytic lesions of the AV3V region and stainless steel cannulas implanted into the NTS or RVLM were used. Mean arterial pressure (MAP) and heart rate (HR) were recorded in unanesthetized rats. A polyethylene tubing was inserted into the abdominal aorta through the femoral artery on day before the experiments. A second polyethylene tubing was inserted in the femoral vein for the baroreflex and chemoreflex tests. The central injections were made using 5 µl Hamilton syringes. The volume of the central injections into the NTS and RVLM was 100 nl. In sham rats, the injection of glutamate (5 nmol) into the NTS produce pressor response (28 ± 3 mmHg). The same dose of glutamate in acute AV3V-lesioned rats produce hypotension (-26 ± 8 mmHg) in the first day after lesion or did not modify the MAP (2 ± 8 mmHg) fifteen days after AV3V lesion. The bradycardic responses produced by injection of the glutamate into the NTS in acute (-65 ± 23 bpm) or cronic (-90 ± 29 bpm) AV3Vlesioned rats were not different from the bradycardic responses produced by glutamate into the NTS in sham-lesioned rats (-76 ± 13 e -90 ± 15 bpm). Differently, the pressor response produced by injection of substance P (0,5 e 1 nmol) into the NTS in acute (16 ± 2 and 20 ± 2 mmHg, respectively) or chronic AV3V-lesioned rats (18 ± 1 and 20 ± 1 mmHg) were not different from the pressor responses produced by the same doses of substance P into the NTS in acute (20 ± 5 and 22 ± 3 mmHg) or chronic sham rats (19 ± 3 and 25 ± 3 mmHg). The tachycardic responses produced by injection of substance P into the NTS in acute (54 ± 15 and 71 ± 15 bpm) and chronic AV3V-lesioned rats (70 ± 11 and 66 ± 11 bpm) were also not different from the tachycardic responses produced by substance P into the NTS in acute (75 ± 14 and 72 ± 12 bpm) or chronic sham rats (53 ± 16 e 84 ± 7 bpm). The pressor responses produced by injections of glutamate (1, 5 and 10 nmol) into the RVLM in acute (9 ± 4, 39 ± 6 e 37 ± 4 mmHg, respectively) or chronic AV3V-lesioned rats (13 ± 6, 39 ± 4 and 43 ± 4 mmHg, respectively) were significantly reduced compared to the pressor responses of the same doses of glutamate into the RVLM in acute (33 ± 5, 54 ± 3 and 56 ± 8 mmHg, respectively) or chronic sham rats (29 ± 3, 50 ± 2 and 58 ± 3 mmHg, respectively). Glutamate into the RVLM in acute or chronic sham or AV3V lesioned rats produced no significant change in the heart rate. The baroreflex responses produced by iv phenylephrine (5 µg/kg of body weight), sodium nitroprussiade (30 µg/kg of body weight), or the responses produced by chemoreflex activation with iv injection of potassium cyanide (20 and 40 µg/rato) were not modified by acute or chronic AV3V lesion. The results show the importance of the AV3V region for the cardiovascular responses dependent on the activation of the sympathetic nervous system and specially the pressor responses to glutamatergic activation in the NTS and RVLM. The integrity of the AV3V region is important for the pressor responses to injection of glutamate into the NTS and into the RVLM, but not for the pressor response to injection of substance P into the NTS, which suggests that the AV3V lesion does not non specifically affect any pressor mechanism. The AV3V lesions do not modify the baro and chemoreflex responses, suggesting that the sympatoexcitatory responses to chemoreflex activation do not depend unique and exclusively on glutamatergic neurotransmission in the NTS and RVLM. / Respostas cardiovasculares podem ser integradas em diferentes níveis do sistema nervoso central (SNC). Em particular, o hipotálamo e o bulbo estão muito envolvidos com o controle de respostas autonômicas, entre as quais estão as repostas cardiovasculares. No bulbo estão vários núcleos importantes para o controle cardiovascular como o núcleo do trato solitário (NTS), as áreas rostroventrolateral (RVL) e caudoventrolateral (CVL) e o núcleo ambíguo. Um circuito envolvendo essas áreas bulbares é responsável pelo controle básico do sistema cardiovascular, podendo receber informações dos receptores localizados em diferentes partes do organismo, em especial dos pressorreceptores e quimiorreceptores e, integrando essas informações de diversas origens, comandar as eferências autonômicas. Injeção do aminoácido excitatório glutamato no NTS de ratos anestesiados produz resposta hipotensora e bradicárdica semelhante à ativação do barorreflexo. Diferentemente, em animais não anestesiados, a injeção de glutamato no NTS provoca resposta pressora e bradicárdica, semelhante á ativação do quimiorreflexo. A substância P é um neuropeptídeo que também quando injetada no NTS produz efeito pressor, podendo atuar como neurotransmissor ou neuromodulador dos diferentes reflexos cardiovasculares. A área RVL é o principal sítio de saída simpática para a coluna intermédio lateral (IML). Injeção de glutamato na área RVL produz disparos dos neurônios simpáticos para a IML produzindo resposta pressora. É bem relatado, que áreas hipotalâmicas exercem forte modulação sobre respostas cardiovasculares. Uma dessas áreas é o núcleo paraventricular do hipotálamo (NPV), cuja lesão eletrolítica reduz a resposta pressora à ativação do quimiorreflexo com cianeto de potássio i.v. Uma outra área hipotalâmica muito importante para o controle cardiovascular é a região anteroventral do terceiro ventrículo (AV3V), cuja lesão reduz as respostas cardiovasculares produzidas pela ativação colinérgica e angiotensinérgica central e impede o desenvolvimento de diversas formas de hipertensão em animais. No presente estudo o objetivo foi estudar em ratos não anestesiados, os efeitos da lesão aguda (1 dia) e crônica (15 dias) da região AV3V sobre as respostas pressoras produzidas pela ativação do NTS com injeção do aminoácido excitatório glutamato e da taquicinina substância P ou pela injeção de glutamato na área RVL, além de se testar as respostas à ativação tanto do barorreflexo quanto do quimiorreflexo. Para isso foram utilizados ratos com lesão eletrolítica ou lesão fictícia da região AV3V aguda ou crônica e com cânulas de aço inoxidável implantadas no NTS ou na área RVL. A pressão arterial média (PAM) e a frequência cardíaca (FC) foram registradas em ratos não anestesiados que tiveram a artéria femoral canulada com tubo de polietileno (PE 10) no dia anterior ao do registro. A veia femoral também foi canulada para injeções das drogas periféricas para os teste de baro e quimiorreflexo. As injeções centrais no volume de 100 nl foram feitas com auxílio de uma seringa Hamilton de 5 µl. Enquanto que nos ratos com lesão fictícia (1 e 15 dias), a injeção de glutamato (5 nmol) no NTS produziu respostas pressoras (28 ± 3 mmHg), a mesma injeção nos ratos com lesão da região AV3V produziu hipotensão (-26 ± 8 mmHg) no 1o dia após a lesão ou não modificou a PAM (2 ± 8 mmHg) 15 dias após a lesão da região AV3V. A resposta bradicárdica produzida pela injeção de glutamato no NTS de ratos com lesão eletrolítica aguda (-65 ± 23 bpm) e crônica (-90 ± 29 bpm) não foram diferentes das respostas bradicárdicas produzidas pela injeção de glutamato no NTS nos respectivos controles com lesão fictícia (-76 ± 13 e -90 ± 15 bpm). Diferentemente do ocorrido com injeções de glutamato, as respostas pressoras produzidas pelas injeções de substância P (0,5 e 1 nmol) no NTS de ratos com lesão da região AV3V aguda (16 ± 2 e 20 ± 2 mmHg, respectivamente) ou crônica (18 ± 1 e 20 ± 1 mmHg) não foram diferentes das respostas pressoras produzidas pela injeção das mesmas doses de substância P no NTS de ratos com lesão fictícia aguda (20 ± 5 e 22 ± 3 mmHg) ou crônica (19 ± 3 e 25 ± 3 mmHg). As respostas taquicárdicas produzidas pela injeção de substância P no NTS de ratos com lesão da região AV3V aguda (54 ± 15 e 71 ± 15 bpm) e crônica (70 ± 11 e 66 ± 11 bpm) não foram diferentes das respostas taquicárdicas produzidas pela injeção de substância P no NTS de ratos com lesão fictícia aguda (75 ± 14 e 72 ± 12 bpm) ou crônica (53 ± 16 e 84 ± 7 bpm). Por outro lado, as respostas pressoras produzidas pelas injeções de glutamato (1, 5 e 10 nmol) na área RVL de ratos com lesão da região AV3V aguda (9 ± 4, 39 ± 6 e 37 ± 4 mmHg, respectivamente) ou crônica (13 ± 6, 39 ± 4 e 43 ± 4 mmHg, respectivamente) foram significativamente reduzidas em relação às respostas pressoras produzidas pelas injeções das mesmas doses de glutamato na área RVL de ratos com lesão fictícia aguda (33 ± 5, 54 ± 3 e 56 ± 8 mmHg, respectivamente) ou crônica (29 ± 3, 50 ± 2 e 58 ± 3 mmHg, respectivamente). Não se observaram diferenças nas respostas bradicárdicas produzidas pelas injeções de glutamato nos ratos com lesão da região AV3V (aguda ou crônica) em relação aos ratos com lesão fictícia. As respostas barorreflexas produzidas pelas injeções i.v. de fenilefrina (5 µg/kg de peso corporal) ou nitroprussiato de sódio (30 µg/kg), assim como nas respostas produzidas pela ativação do quimiorreflexo com injeções i.v. de cianeto de potássio (20 e 40 µg/rato) também não foram modificadas pela lesão da região AV3V tanto aguda como crônica. Esses resultados mostram a grande importância que a região AV3V têm para as respostas cardiovasculares dependentes da ativação do sistema nervoso simpático e, nesse caso em especial, respostas pressoras à ativação glutamatérgica de áreas bulbares. Pelos resultados obtidos, pode-se sugerir, que a região AV3V participa de uma forma decisiva nas respostas pressoras resultantes da injeção de glutamato no NTS e na área RVL, mas não na resposta pressora à injeção de substância P no NTS. Isso demonstra que o efeito da lesão da região AV3V não depende de um comprometimento inespecífico de mecanismos pressores. Um outro resultado importante desse estudo, é que a lesão da região AV3V não modifica as respostas baro e quimiorreflexa, podendo sugerir, que a resposta simpato-excitatória do quimiorreflexo não depende única e exclusivamente da neurotransmissão glutamatérgica em área bulbares.

Lectins are multivalent carbohydrate binding proteins that specifically recognise diverse sugar structures and mediate a variety of biological processes, such as cell-cell and host-pathogen interactions, serum glycoprotein turnover and innate immune responses. Lectins have received considerable attention in recent years on account of their properties leading to wide use in research and biomedical applications. Seeds of leguminous plants are mainly rich sources of lectins, but lectins are also found in all classes and families of organisms. Legume lectins have similar tertiary structures, but exhibit a large variety of quaternary structures. The carbohydrate binding site in them is made up of four loops, the first three of which are highly conserved in all legume lectins. The fourth loop, which is variable, is implicated in conferring specificity. Legume lectins which share the same monosaccharide specificity often exhibit markedly different oligosaccharide specificities. This thesis primarily concerns with structure solution and analysis of lectins from the legume and β-prism II fold families using X-ray crystallography. Apart from having the property of specifically and reversibly binding to carbohydrates, lectins are also interesting models to study sequence-structure relationships, especially of how minor change in the sequence may bring about major changes in oligomerization and binding. Chapter 1 gives an overview of different structural types of plant lectins and describes in detail, their carbohydrate binding features. The details of the various experimental procedures employed during the course of this research, are explained in Chapter 2. Chapter 3 describes the crystal structure of a β-prism II fold lectin (RVL), from Remusatia vivipara, an epiphytic plant of traditional medicinal value, and analysis of its binding properties. This lectin was established to have distinct binding properties and has nematicidal activity against a root-knot nematode with the localization site identified as the high-mannose displaying gut-lining in the nematode. The crystal structure of RVL revealed a new quaternary association of this homodimeric lectin, different from those of reported β-prism II lectins. Functional studies on RVL showed that it fails to bind to simple mannose moieties yet showed agglutination with rabbit blood cells (which have mannose moieties on the surface) and some high mannose containing glycoproteins like mucin and asialofetuin. Further, ELISA and glycan array experiments indicated that RVL has high affinity to N-glycans like trimannose pentasaccharide such as in gp120, a capsid glycoprotein of HIV virus, necessary in virus-association with the host cell. The structural basis for this N-glycan binding was revealed through structure analysis and molecular modelling, and it was demonstrated that there are two distinct binding sites per monomer, making RVL a truly multivalent lectin. Evolutionary phylogeny revealed the divergence in the β-prism II fold proteins with regards to the number of sugar-binding regions per domain, oligomerization and specificity. Chapter 4 deals with the structural studies on a galactose-specific legume lectin (DLL-II) from Dolichos lablab, a leguminous plant. The lectin was found to be a planar tetramer in the crystal structures of the native and ligand bound forms, as expected from our solution studies and phylogenetic analysis. The protein is a heterotetramer with subunits differing only in the presence or absence of a C-terminal helical region at the core of the tetramer. Due to the static disorder in all the crystals, the central helix could be oriented in either direction. Structure analysis of DLL-II proved to be an interesting endeavour as static disorder compounded with twinning in the crystal made the data processing and structure solution a challenging process. Subsequent structure and sequence alignments led to the identification of an adenine-binding pocket in the hydrophobic core of the tetramer. Based on this, DLL-II lectin was co-crystallized with adenine and the structure revealed the presence of adenine at the predicted binding site. Chapter 5 describes the identification and analysis of potential plant lectins/lectin-like domains in the genome of Oryza sativa, using bioinformatics approaches. This project was initiated to study the occurrence of legume-lectin like domains (a predominant dicot feature) in O. sativa, which is a monocot. Later, a large scale genome analysis for all types of lectin domains was carried out through exhaustive PSI-BLAST, profile matching by HMMer, CDD and MulPSSM. The final validation was carried out by assessing the carbohydrate binding potential of the domain by examining the sugar binding sites. The primary interest in undertaking this work was to find the occurrence of association of these domains with other domains as in protein receptor kinases, where lectin is the receptor domain. Though primarily initiated as a bioinformatics project, further structural characterization was attempted by cloning, expression and purification of some of the annotated lectin proteins using prokaryotic expression systems. The protein expression was attained in reasonable amounts for a few of the annotated legume lectin homologs, however purification is yet to be achieved as the expressed proteins are insoluble. A part of the results described in this thesis and the other related projects that the author was involved are reported in the following publications. 1) Purification, characterization and molecular cloning of a monocot mannose-binding lectin from Remusatia vivipara with nematicidal activity Bhat GG, Shetty KN, Nagre NN, Neekhra VV, Lingaraju S, Bhat RS, Inamdar SR, Suguna K, Swamy BM. 2010. Glycoconjugate J. 27(3):309-320 2) Modification of the sugar specificity of a plant lectin: structural studies on a point mutant of Erythrina corallodendron lectin Thamotharan S, Karthikeyan T, Kulkarni KA, Shetty KN, Surolia A, Vijayan M & Suguna K. 2011. Acta Crystallographica D 67(3):218-227 3) Crystal structure of a β-prism II lectin from Remusatia vivipara Shetty KN, Bhat GG, Inamdar SR, Swamy BM, Suguna K. 2012. Glycobiology 22(1): 56-69. 4) Structure of a galactose binding lectin from Dolichos lablab Shetty KN, Lavanyalatha V, Rao RN, SivaKumar N & Suguna K (Under review) 5) Occurrence of lectin-like domains: Oryza sativa genome analysis. Shetty KN & Suguna K. (Manuscript in preparation)

This study examines the efficacy of Sentinel-1 Radial Velocity (RVL) imagery at determining the position of ocean current front features, using the Gulf Stream (GS) and Agulhas Current (AC) as case studies. Fronts derived from RVL imagery are compared to fronts derived from Sea Surface Temperature (SST) imagery, specifically Multi-scale Ultra-high Resolution Sea Surface Temperature Analysis (MURSST) data. In the case of the GS, front locations from the Naval Oceanographic Office (NAVOCEANO) were also used for comparison. Only the northern walls of ocean current features are considered in this study, which is broken into three main steps: Preprocessing, front extraction, and front comparison. First, RVL imagery is selected from Sentinel-1 ocean products, preprocessed to remove antenna mispointing artifacts, and all products from the same orbit are combined into a single swath. Second, front features are extracted from both the RVL and MURSST imagery using a ridge detection algorithm, the main ocean current is chosen from all ridge features using a ranking algorithm, and the northern wall of this current is extracted. Third, the RVL, SST, and in the case of the GS, NAVOCEANO GS locations, features are compared using a symmetric Hausdorff Distance (HD) measure, and Mean Hausdorff Distance (MHD). In some cases, the automatic front extraction failed by either misclassifying an eddy or similar ocean feature as the ocean current in either the RVL or SST image or failed to extract the entire length of the front visible within the image. All the SST and RVL fronts were classified manually to determine the success rate of the automatic front extraction and to exclude failed front extractions from the analysis, as they are not accurate representations of the SST and RVL data’s ability to detect fronts. In special cases, the RVL image itself does not detect the entire ocean current, such that there are noticeable gaps in the ocean current. Similarly, in special cases the MURSST does not detect the entire ocean current. The automatic front extraction succeeded 65% of the time, including the special cases. The results demonstrated that RVL products were effective at determining the location of ocean fronts where the angle of the front's normal vector is within approximately 40° of the sensor’s azimuthal heading. A mean HD of 31.9 km and a mean MHD of 13.2 km was calculated for all front pairs over all study areas. The RVL fronts appeared consistently to the north of the SST fronts, with an average offset of 25.4 km between the centroids of the SST and RVL fronts. Positive correlations were noted between cloud coverage and MURSST error in both study regions. Several RVL images detected ocean currents in regions of high MURSST error where the MURSST did not detect the ocean currents, suggesting that RVL may provide more accuracy than SST-based products in clouded regions where there is no auxiliary data.

Data masses on the World Wide Web can hardly be managed by humans or machines. One option is the formal description and linking of data sources using Semantic Web and Linked Data technologies. Ontologies written in standardised languages foster the sharing and linking of data as they provide a means to formally define concepts and relations between these concepts. A second option is visualisation. The visual representation allows humans to perceive information more directly, using the highly developed visual sense. Relatively few efforts have been made on combining both options, although the formality and rich semantics of ontological data make it an ideal candidate for visualisation. Advanced visualisation design systems support the visualisation of tabular, typically statistical data. However, visualisations of ontological data still have to be created manually, since automated solutions are often limited to generic lists or node-link diagrams. Also, the semantics of ontological data are not exploited for guiding users through visualisation tasks. Finally, once a good visualisation setting has been created, it cannot easily be reused and shared. Trying to tackle these problems, we had to answer how to define composable and shareable mappings from ontological data to visual means and how to guide the visual mapping of ontological data. We present an approach that allows for the guided visualisation of ontological data, the creation of effective graphics and the reuse of visualisation settings. Instead of generic graphics, we aim at tailor-made graphics, produced using the whole palette of visual means in a flexible, bottom-up approach. It not only allows for visualising ontologies, but uses ontologies to guide users when visualising data and to drive the visualisation process at various places: First, as a rich source of information on data characteristics, second, as a means to formally describe the vocabulary for building abstract graphics, and third, as a knowledge base of facts on visualisation. This is why we call our approach ontology-driven. We suggest generating an Abstract Visual Model (AVM) to represent and »synthesise« a graphic following a role-based approach, inspired by the one used by J. v. Engelhardt for the analysis of graphics. It consists of graphic objects and relations formalised in the Visualisation Ontology (VISO). A mappings model, based on the declarative RDFS/OWL Visualisation Language (RVL), determines a set of transformations from the domain data to the AVM. RVL allows for composable visual mappings that can be shared and reused across platforms. To guide the user, for example, we discourage the construction of mappings that are suboptimal according to an effectiveness ranking formalised in the fact base and suggest more effective mappings instead. The guidance process is flexible, since it is based on exchangeable rules. VISO, RVL and the AVM are additional contributions of this thesis. Further, we initially analysed the state of the art in visualisation and RDF-presentation comparing 10 approaches by 29 criteria. Our approach is unique because it combines ontology-driven guidance with composable visual mappings. Finally, we compare three prototypes covering the essential parts of our approach to show its feasibility. We show how the mapping process can be supported by tools displaying warning messages for non-optimal visual mappings, e.g., by considering relation characteristics such as »symmetry«. In a constructive evaluation, we challenge both the RVL language and the latest prototype trying to regenerate sketches of graphics we created manually during analysis. We demonstrate how graphics can be varied and complex mappings can be composed from simple ones. Two thirds of the sketches can be almost or completely specified and half of them can be almost or completely implemented. / Datenmassen im World Wide Web können kaum von Menschen oder Maschinen erfasst werden. Eine Option ist die formale Beschreibung und Verknüpfung von Datenquellen mit Semantic-Web- und Linked-Data-Technologien. Ontologien, in standardisierten Sprachen geschrieben, befördern das Teilen und Verknüpfen von Daten, da sie ein Mittel zur formalen Definition von Konzepten und Beziehungen zwischen diesen Konzepten darstellen. Eine zweite Option ist die Visualisierung. Die visuelle Repräsentation ermöglicht es dem Menschen, Informationen direkter wahrzunehmen, indem er seinen hochentwickelten Sehsinn verwendet. Relativ wenige Anstrengungen wurden unternommen, um beide Optionen zu kombinieren, obwohl die Formalität und die reichhaltige Semantik ontologische Daten zu einem idealen Kandidaten für die Visualisierung machen. Visualisierungsdesignsysteme unterstützen Nutzer bei der Visualisierung von tabellarischen, typischerweise statistischen Daten. Visualisierungen ontologischer Daten jedoch müssen noch manuell erstellt werden, da automatisierte Lösungen häufig auf generische Listendarstellungen oder Knoten-Kanten-Diagramme beschränkt sind. Auch die Semantik der ontologischen Daten wird nicht ausgenutzt, um Benutzer durch Visualisierungsaufgaben zu führen. Einmal erstellte Visualisierungseinstellungen können nicht einfach wiederverwendet und geteilt werden. Um diese Probleme zu lösen, mussten wir eine Antwort darauf finden, wie die Definition komponierbarer und wiederverwendbarer Abbildungen von ontologischen Daten auf visuelle Mittel geschehen könnte und wie Nutzer bei dieser Abbildung geführt werden könnten. Wir stellen einen Ansatz vor, der die geführte Visualisierung von ontologischen Daten, die Erstellung effektiver Grafiken und die Wiederverwendung von Visualisierungseinstellungen ermöglicht. Statt auf generische Grafiken zielt der Ansatz auf maßgeschneiderte Grafiken ab, die mit der gesamten Palette visueller Mittel in einem flexiblen Bottom-Up-Ansatz erstellt werden. Er erlaubt nicht nur die Visualisierung von Ontologien, sondern verwendet auch Ontologien, um Benutzer bei der Visualisierung von Daten zu führen und den Visualisierungsprozess an verschiedenen Stellen zu steuern: Erstens als eine reichhaltige Informationsquelle zu Datencharakteristiken, zweitens als Mittel zur formalen Beschreibung des Vokabulars für den Aufbau von abstrakten Grafiken und drittens als Wissensbasis von Visualisierungsfakten. Deshalb nennen wir unseren Ansatz ontologie-getrieben. Wir schlagen vor, ein Abstract Visual Model (AVM) zu generieren, um eine Grafik rollenbasiert zu synthetisieren, angelehnt an einen Ansatz der von J. v. Engelhardt verwendet wird, um Grafiken zu analysieren. Das AVM besteht aus grafischen Objekten und Relationen, die in der Visualisation Ontology (VISO) formalisiert sind. Ein Mapping-Modell, das auf der deklarativen RDFS/OWL Visualisation Language (RVL) basiert, bestimmt eine Menge von Transformationen von den Quelldaten zum AVM. RVL ermöglicht zusammensetzbare »Mappings«, visuelle Abbildungen, die über Plattformen hinweg geteilt und wiederverwendet werden können. Um den Benutzer zu führen, bewerten wir Mappings anhand eines in der Faktenbasis formalisierten Effektivitätsrankings und schlagen ggf. effektivere Mappings vor. Der Beratungsprozess ist flexibel, da er auf austauschbaren Regeln basiert. VISO, RVL und das AVM sind weitere Beiträge dieser Arbeit. Darüber hinaus analysieren wir zunächst den Stand der Technik in der Visualisierung und RDF-Präsentation, indem wir 10 Ansätze nach 29 Kriterien vergleichen. Unser Ansatz ist einzigartig, da er eine ontologie-getriebene Nutzerführung mit komponierbaren visuellen Mappings vereint. Schließlich vergleichen wir drei Prototypen, welche die wesentlichen Teile unseres Ansatzes umsetzen, um seine Machbarkeit zu zeigen. Wir zeigen, wie der Mapping-Prozess durch Tools unterstützt werden kann, die Warnmeldungen für nicht optimale visuelle Abbildungen anzeigen, z. B. durch Berücksichtigung von Charakteristiken der Relationen wie »Symmetrie«. In einer konstruktiven Evaluation fordern wir sowohl die RVL-Sprache als auch den neuesten Prototyp heraus, indem wir versuchen Skizzen von Grafiken umzusetzen, die wir während der Analyse manuell erstellt haben. Wir zeigen, wie Grafiken variiert werden können und komplexe Mappings aus einfachen zusammengesetzt werden können. Zwei Drittel der Skizzen können fast vollständig oder vollständig spezifiziert werden und die Hälfte kann fast vollständig oder vollständig umgesetzt werden.

Data masses on the World Wide Web can hardly be managed by humans or machines. One option is the formal description and linking of data sources using Semantic Web and Linked Data technologies. Ontologies written in standardised languages foster the sharing and linking of data as they provide a means to formally define concepts and relations between these concepts. A second option is visualisation. The visual representation allows humans to perceive information more directly, using the highly developed visual sense. Relatively few efforts have been made on combining both options, although the formality and rich semantics of ontological data make it an ideal candidate for visualisation. Advanced visualisation design systems support the visualisation of tabular, typically statistical data. However, visualisations of ontological data still have to be created manually, since automated solutions are often limited to generic lists or node-link diagrams. Also, the semantics of ontological data are not exploited for guiding users through visualisation tasks. Finally, once a good visualisation setting has been created, it cannot easily be reused and shared. Trying to tackle these problems, we had to answer how to define composable and shareable mappings from ontological data to visual means and how to guide the visual mapping of ontological data. We present an approach that allows for the guided visualisation of ontological data, the creation of effective graphics and the reuse of visualisation settings. Instead of generic graphics, we aim at tailor-made graphics, produced using the whole palette of visual means in a flexible, bottom-up approach. It not only allows for visualising ontologies, but uses ontologies to guide users when visualising data and to drive the visualisation process at various places: First, as a rich source of information on data characteristics, second, as a means to formally describe the vocabulary for building abstract graphics, and third, as a knowledge base of facts on visualisation. This is why we call our approach ontology-driven. We suggest generating an Abstract Visual Model (AVM) to represent and »synthesise« a graphic following a role-based approach, inspired by the one used by J. v. Engelhardt for the analysis of graphics. It consists of graphic objects and relations formalised in the Visualisation Ontology (VISO). A mappings model, based on the declarative RDFS/OWL Visualisation Language (RVL), determines a set of transformations from the domain data to the AVM. RVL allows for composable visual mappings that can be shared and reused across platforms. To guide the user, for example, we discourage the construction of mappings that are suboptimal according to an effectiveness ranking formalised in the fact base and suggest more effective mappings instead. The guidance process is flexible, since it is based on exchangeable rules. VISO, RVL and the AVM are additional contributions of this thesis. Further, we initially analysed the state of the art in visualisation and RDF-presentation comparing 10 approaches by 29 criteria. Our approach is unique because it combines ontology-driven guidance with composable visual mappings. Finally, we compare three prototypes covering the essential parts of our approach to show its feasibility. We show how the mapping process can be supported by tools displaying warning messages for non-optimal visual mappings, e.g., by considering relation characteristics such as »symmetry«. In a constructive evaluation, we challenge both the RVL language and the latest prototype trying to regenerate sketches of graphics we created manually during analysis. We demonstrate how graphics can be varied and complex mappings can be composed from simple ones. Two thirds of the sketches can be almost or completely specified and half of them can be almost or completely implemented.:Legend and Overview of Prefixes xiii 1 Introduction 1 2 Background 11 2.1 Visualisation 11 2.1.1 What is Visualisation? 11 2.1.2 What are the Benefits of Visualisation? 12 2.1.3 Visualisation Related Terms Used in this Thesis 12 2.1.4 Visualisation Models and Architectural Patterns 12 2.1.5 Visualisation Design Systems 14 2.1.6 What is the Difference between Visual Mapping and Styling? 14 2.1.7 Lessons Learned from Style Sheet Languages 15 2.2 Data 16 2.2.1 Data – Information – Knowledge 17 2.2.2 Structured Data 17 2.2.3 Ontologies in Computer Science 19 2.2.4 The Semantic Web and its Languages 19 2.2.5 Linked Data and Open Data 20 2.2.6 The Metamodelling Technological Space 21 2.2.7 SPIN 21 2.3 Guidance 22 2.3.1 Guidance in Visualisation 22 3 Problem Analysis 23 3.1 Problems of Ontology Visualisation Approaches 24 3.2 Research Questions 25 3.3 Set up of the Case Studies 25 3.3.1 Case Studies in the Life Sciences Domain 26 3.3.2 Case Studies in the Publishing Domain 26 3.3.3 Case Studies in the Software Technology Domain 27 3.4 Analysis of the Case Studies’ Ontologies 27 3.5 Manual Sketching of Graphics 29 3.6 Analysis of the Graphics for Typical Visualisation Cases 29 3.7 Requirements 33 3.7.1 Requirements for Visualisation and Interaction 34 3.7.2 Requirements for Data Awareness 34 3.7.3 Requirements for Reuse and Composition 34 3.7.4 Requirements for Variability 35 3.7.5 Requirements for Tooling Support and Guidance 35 3.7.6 Optional Features and Limitations 36 4 Analysis of the State of the Art 37 4.1 Related Visualisation Approaches 38 4.1.1 Short Overview of the Approaches 38 4.1.2 Detailed Comparison by Criteria 46 4.1.3 Conclusion – What Is Still Missing? 60 4.2 Visualisation Languages 62 4.2.1 Short Overview of the Compared Languages 62 4.2.2 Detailed Comparison by Language Criteria 66 4.2.3 Conclusion – What Is Still Missing? 71 4.3 RDF Presentation Languages 72 4.3.1 Short Overview of the Compared Languages 72 4.3.2 Detailed Comparison by Language Criteria 76 4.3.3 Additional Criteria for RDF Display Languages 87 4.3.4 Conclusion – What Is Still Missing? 89 4.4 Model-Driven Interfaces 90 4.4.1 Metamodel-Driven Interfaces 90 4.4.2 Ontology-Driven Interfaces 92 4.4.3 Combined Usage of the Metamodelling and Ontology Technological Space 94 5 A Visualisation Ontology – VISO 97 5.1 Methodology Used for Ontology Creation 100 5.2 Requirements for a Visualisation Ontology 100 5.3 Existing Approaches to Modelling in the Field of Visualisation 101 5.3.1 Terminologies and Taxonomies 101 5.3.2 Existing Visualisation Ontologies 102 5.3.3 Other Visualisation Models and Approaches to Formalisation 103 5.3.4 Summary 103 5.4 Technical Aspects of VISO 103 5.5 VISO/graphic Module – Graphic Vocabulary 104 5.5.1 Graphic Representations and Graphic Objects 105 5.5.2 Graphic Relations and Syntactic Structures 107 5.6 VISO/data Module – Characterising Data 110 5.6.1 Data Structure and Characteristics of Relations 110 5.6.2 The Scale of Measurement and Units 112 5.6.3 Properties for Characterising Data Variables in Statistical Data 113 5.7 VISO/facts Module – Facts for Vis. Constraints and Rules 115 5.7.1 Expressiveness of Graphic Relations 116 5.7.2 Effectiveness Ranking of Graphic Relations 118 5.7.3 Rules for Composing Graphics 119 5.7.4 Other Rules to Consider for Visual Mapping 124 5.7.5 Providing Named Value Collections 124 5.7.6 Existing Approaches to the Formalisation of Visualisation Knowledge . . 126 5.7.7 The VISO/facts/empiric Example Knowledge Base 126 5.8 Other VISO Modules 126 5.9 Conclusions and Future Work 127 5.10 Further Use Cases for VISO 127 5.11 VISO on the Web – Sharing the Vocabulary to Build a Community 128 6 A VISO-Based Abstract Visual Model – AVM 129 6.1 Graphical Notation Used in this Chapter 129 6.2 Elementary Graphic Objects and Graphic Attributes 131 6.3 N-Ary Relations 131 6.4 Binary Relations 131 6.5 Composition of Graphic Objects Using Roles 132 6.6 Composition of Graphic Relations Using Roles 132 6.7 Composition of Visual Mappings Using the AVM 135 6.8 Tracing 135 6.9 Is it Worth Having an Abstract Visual Model? 135 6.10 Discussion of Fresnel as a Related Language 137 6.11 Related Work 139 6.12 Limitations 139 6.13 Conclusions 140 7 A Language for RDFS/OWL Visualisation – RVL 141 7.1 Language Requirements 142 7.2 Main RVL Constructs 145 7.2.1 Mapping 145 7.2.2 Property Mapping 146 7.2.3 Identity Mapping 146 7.2.4 Value Mapping 147 7.2.5 Inheriting RVL Settings 147 7.2.6 Resource Mapping 148 7.2.7 Simplifications 149 7.3 Calculating Value Mappings 150 7.4 Defining Scale of Measurement 153 7.4.1 Determining the Scale of Measurement 154 7.5 Addressing Values in Value Mappings 156 7.5.1 Determining the Set of Addressed Source Values 156 7.5.2 Determining the Set of Addressed Target Values 157 7.6 Overlapping Value Mappings 158 7.7 Default Value Mapping 158 7.8 Default Labelling 159 7.9 Defining Interaction 159 7.10 Mapping Composition and Submappings 160 7.11 A Schema Language for RVL 160 7.11.1 Concrete Examples of the RVL Schema 163 7.12 Conclusions and Future Work 166 8 The OGVIC Approach 169 8.1 Ontology-Driven, Guided Editing of Visual Mappings 172 8.1.1 Classification of Constraints 172 8.1.2 Levels of Guidance 173 8.1.3 Implementing Constraint-Based Guidance 173 8.2 Support of Explicit and Composable Visual Mappings 177 8.2.1 Mapping Composition Cases 178 8.2.2 Selecting a Context 180 8.2.3 Using the Same Graphic Relation Multiple Times 181 8.3 Prototype P1 (TopBraid-Composer-based) 182 8.4 Prototype P2 (OntoWiki-based) 184 8.5 Prototype P3 (Java Implementation of RVL) 187 8.6 Lessons Learned from Prototypes & Future Work 190 8.6.1 Checking RVL Constraints and Visualisation Rules 190 8.6.2 A User Interface for Editing RVL Mappings 190 8.6.3 Graph Transformations with SPIN and SPARQL 1.1 Update 192 8.6.4 Selection and Filtering of Data 193 8.6.5 Interactivity and Incremental Processing 193 8.6.6 Rendering the Final Platform-Specific Code 196 9 Application 197 9.1 Coverage of Case Study Sketches and Necessary Features 198 9.2 Coverage of Visualisation Cases 201 9.3 Coverage of Requirements 205 9.4 Full Example 206 10 Conclusions 211 10.1 Contributions 211 10.2 Constructive Evaluation 212 10.3 Research Questions 213 10.4 Transfer to Other Models and Constraint Languages 213 10.5 Limitations 214 10.6 Future Work 214 Appendices 217 A Case Study Sketches 219 B VISO – Comparison of Visualisation Literature 229 C RVL 231 D RVL Example Mappings and Application 233 D.1 Listings of RVL Example Mappings as Required by Prototype P3 233 D.2 Features Required for Implementing all Sketches 235 D.3 JSON Format for Processing the AVM with D3 – Hierarchical Variant 238 Bibliography 238 List of Figures 251 List of Tables 254 List of Listings 257 / Datenmassen im World Wide Web können kaum von Menschen oder Maschinen erfasst werden. Eine Option ist die formale Beschreibung und Verknüpfung von Datenquellen mit Semantic-Web- und Linked-Data-Technologien. Ontologien, in standardisierten Sprachen geschrieben, befördern das Teilen und Verknüpfen von Daten, da sie ein Mittel zur formalen Definition von Konzepten und Beziehungen zwischen diesen Konzepten darstellen. Eine zweite Option ist die Visualisierung. Die visuelle Repräsentation ermöglicht es dem Menschen, Informationen direkter wahrzunehmen, indem er seinen hochentwickelten Sehsinn verwendet. Relativ wenige Anstrengungen wurden unternommen, um beide Optionen zu kombinieren, obwohl die Formalität und die reichhaltige Semantik ontologische Daten zu einem idealen Kandidaten für die Visualisierung machen. Visualisierungsdesignsysteme unterstützen Nutzer bei der Visualisierung von tabellarischen, typischerweise statistischen Daten. Visualisierungen ontologischer Daten jedoch müssen noch manuell erstellt werden, da automatisierte Lösungen häufig auf generische Listendarstellungen oder Knoten-Kanten-Diagramme beschränkt sind. Auch die Semantik der ontologischen Daten wird nicht ausgenutzt, um Benutzer durch Visualisierungsaufgaben zu führen. Einmal erstellte Visualisierungseinstellungen können nicht einfach wiederverwendet und geteilt werden. Um diese Probleme zu lösen, mussten wir eine Antwort darauf finden, wie die Definition komponierbarer und wiederverwendbarer Abbildungen von ontologischen Daten auf visuelle Mittel geschehen könnte und wie Nutzer bei dieser Abbildung geführt werden könnten. Wir stellen einen Ansatz vor, der die geführte Visualisierung von ontologischen Daten, die Erstellung effektiver Grafiken und die Wiederverwendung von Visualisierungseinstellungen ermöglicht. Statt auf generische Grafiken zielt der Ansatz auf maßgeschneiderte Grafiken ab, die mit der gesamten Palette visueller Mittel in einem flexiblen Bottom-Up-Ansatz erstellt werden. Er erlaubt nicht nur die Visualisierung von Ontologien, sondern verwendet auch Ontologien, um Benutzer bei der Visualisierung von Daten zu führen und den Visualisierungsprozess an verschiedenen Stellen zu steuern: Erstens als eine reichhaltige Informationsquelle zu Datencharakteristiken, zweitens als Mittel zur formalen Beschreibung des Vokabulars für den Aufbau von abstrakten Grafiken und drittens als Wissensbasis von Visualisierungsfakten. Deshalb nennen wir unseren Ansatz ontologie-getrieben. Wir schlagen vor, ein Abstract Visual Model (AVM) zu generieren, um eine Grafik rollenbasiert zu synthetisieren, angelehnt an einen Ansatz der von J. v. Engelhardt verwendet wird, um Grafiken zu analysieren. Das AVM besteht aus grafischen Objekten und Relationen, die in der Visualisation Ontology (VISO) formalisiert sind. Ein Mapping-Modell, das auf der deklarativen RDFS/OWL Visualisation Language (RVL) basiert, bestimmt eine Menge von Transformationen von den Quelldaten zum AVM. RVL ermöglicht zusammensetzbare »Mappings«, visuelle Abbildungen, die über Plattformen hinweg geteilt und wiederverwendet werden können. Um den Benutzer zu führen, bewerten wir Mappings anhand eines in der Faktenbasis formalisierten Effektivitätsrankings und schlagen ggf. effektivere Mappings vor. Der Beratungsprozess ist flexibel, da er auf austauschbaren Regeln basiert. VISO, RVL und das AVM sind weitere Beiträge dieser Arbeit. Darüber hinaus analysieren wir zunächst den Stand der Technik in der Visualisierung und RDF-Präsentation, indem wir 10 Ansätze nach 29 Kriterien vergleichen. Unser Ansatz ist einzigartig, da er eine ontologie-getriebene Nutzerführung mit komponierbaren visuellen Mappings vereint. Schließlich vergleichen wir drei Prototypen, welche die wesentlichen Teile unseres Ansatzes umsetzen, um seine Machbarkeit zu zeigen. Wir zeigen, wie der Mapping-Prozess durch Tools unterstützt werden kann, die Warnmeldungen für nicht optimale visuelle Abbildungen anzeigen, z. B. durch Berücksichtigung von Charakteristiken der Relationen wie »Symmetrie«. In einer konstruktiven Evaluation fordern wir sowohl die RVL-Sprache als auch den neuesten Prototyp heraus, indem wir versuchen Skizzen von Grafiken umzusetzen, die wir während der Analyse manuell erstellt haben. Wir zeigen, wie Grafiken variiert werden können und komplexe Mappings aus einfachen zusammengesetzt werden können. Zwei Drittel der Skizzen können fast vollständig oder vollständig spezifiziert werden und die Hälfte kann fast vollständig oder vollständig umgesetzt werden.:Legend and Overview of Prefixes xiii 1 Introduction 1 2 Background 11 2.1 Visualisation 11 2.1.1 What is Visualisation? 11 2.1.2 What are the Benefits of Visualisation? 12 2.1.3 Visualisation Related Terms Used in this Thesis 12 2.1.4 Visualisation Models and Architectural Patterns 12 2.1.5 Visualisation Design Systems 14 2.1.6 What is the Difference between Visual Mapping and Styling? 14 2.1.7 Lessons Learned from Style Sheet Languages 15 2.2 Data 16 2.2.1 Data – Information – Knowledge 17 2.2.2 Structured Data 17 2.2.3 Ontologies in Computer Science 19 2.2.4 The Semantic Web and its Languages 19 2.2.5 Linked Data and Open Data 20 2.2.6 The Metamodelling Technological Space 21 2.2.7 SPIN 21 2.3 Guidance 22 2.3.1 Guidance in Visualisation 22 3 Problem Analysis 23 3.1 Problems of Ontology Visualisation Approaches 24 3.2 Research Questions 25 3.3 Set up of the Case Studies 25 3.3.1 Case Studies in the Life Sciences Domain 26 3.3.2 Case Studies in the Publishing Domain 26 3.3.3 Case Studies in the Software Technology Domain 27 3.4 Analysis of the Case Studies’ Ontologies 27 3.5 Manual Sketching of Graphics 29 3.6 Analysis of the Graphics for Typical Visualisation Cases 29 3.7 Requirements 33 3.7.1 Requirements for Visualisation and Interaction 34 3.7.2 Requirements for Data Awareness 34 3.7.3 Requirements for Reuse and Composition 34 3.7.4 Requirements for Variability 35 3.7.5 Requirements for Tooling Support and Guidance 35 3.7.6 Optional Features and Limitations 36 4 Analysis of the State of the Art 37 4.1 Related Visualisation Approaches 38 4.1.1 Short Overview of the Approaches 38 4.1.2 Detailed Comparison by Criteria 46 4.1.3 Conclusion – What Is Still Missing? 60 4.2 Visualisation Languages 62 4.2.1 Short Overview of the Compared Languages 62 4.2.2 Detailed Comparison by Language Criteria 66 4.2.3 Conclusion – What Is Still Missing? 71 4.3 RDF Presentation Languages 72 4.3.1 Short Overview of the Compared Languages 72 4.3.2 Detailed Comparison by Language Criteria 76 4.3.3 Additional Criteria for RDF Display Languages 87 4.3.4 Conclusion – What Is Still Missing? 89 4.4 Model-Driven Interfaces 90 4.4.1 Metamodel-Driven Interfaces 90 4.4.2 Ontology-Driven Interfaces 92 4.4.3 Combined Usage of the Metamodelling and Ontology Technological Space 94 5 A Visualisation Ontology – VISO 97 5.1 Methodology Used for Ontology Creation 100 5.2 Requirements for a Visualisation Ontology 100 5.3 Existing Approaches to Modelling in the Field of Visualisation 101 5.3.1 Terminologies and Taxonomies 101 5.3.2 Existing Visualisation Ontologies 102 5.3.3 Other Visualisation Models and Approaches to Formalisation 103 5.3.4 Summary 103 5.4 Technical Aspects of VISO 103 5.5 VISO/graphic Module – Graphic Vocabulary 104 5.5.1 Graphic Representations and Graphic Objects 105 5.5.2 Graphic Relations and Syntactic Structures 107 5.6 VISO/data Module – Characterising Data 110 5.6.1 Data Structure and Characteristics of Relations 110 5.6.2 The Scale of Measurement and Units 112 5.6.3 Properties for Characterising Data Variables in Statistical Data 113 5.7 VISO/facts Module – Facts for Vis. Constraints and Rules 115 5.7.1 Expressiveness of Graphic Relations 116 5.7.2 Effectiveness Ranking of Graphic Relations 118 5.7.3 Rules for Composing Graphics 119 5.7.4 Other Rules to Consider for Visual Mapping 124 5.7.5 Providing Named Value Collections 124 5.7.6 Existing Approaches to the Formalisation of Visualisation Knowledge . . 126 5.7.7 The VISO/facts/empiric Example Knowledge Base 126 5.8 Other VISO Modules 126 5.9 Conclusions and Future Work 127 5.10 Further Use Cases for VISO 127 5.11 VISO on the Web – Sharing the Vocabulary to Build a Community 128 6 A VISO-Based Abstract Visual Model – AVM 129 6.1 Graphical Notation Used in this Chapter 129 6.2 Elementary Graphic Objects and Graphic Attributes 131 6.3 N-Ary Relations 131 6.4 Binary Relations 131 6.5 Composition of Graphic Objects Using Roles 132 6.6 Composition of Graphic Relations Using Roles 132 6.7 Composition of Visual Mappings Using the AVM 135 6.8 Tracing 135 6.9 Is it Worth Having an Abstract Visual Model? 135 6.10 Discussion of Fresnel as a Related Language 137 6.11 Related Work 139 6.12 Limitations 139 6.13 Conclusions 140 7 A Language for RDFS/OWL Visualisation – RVL 141 7.1 Language Requirements 142 7.2 Main RVL Constructs 145 7.2.1 Mapping 145 7.2.2 Property Mapping 146 7.2.3 Identity Mapping 146 7.2.4 Value Mapping 147 7.2.5 Inheriting RVL Settings 147 7.2.6 Resource Mapping 148 7.2.7 Simplifications 149 7.3 Calculating Value Mappings 150 7.4 Defining Scale of Measurement 153 7.4.1 Determining the Scale of Measurement 154 7.5 Addressing Values in Value Mappings 156 7.5.1 Determining the Set of Addressed Source Values 156 7.5.2 Determining the Set of Addressed Target Values 157 7.6 Overlapping Value Mappings 158 7.7 Default Value Mapping 158 7.8 Default Labelling 159 7.9 Defining Interaction 159 7.10 Mapping Composition and Submappings 160 7.11 A Schema Language for RVL 160 7.11.1 Concrete Examples of the RVL Schema 163 7.12 Conclusions and Future Work 166 8 The OGVIC Approach 169 8.1 Ontology-Driven, Guided Editing of Visual Mappings 172 8.1.1 Classification of Constraints 172 8.1.2 Levels of Guidance 173 8.1.3 Implementing Constraint-Based Guidance 173 8.2 Support of Explicit and Composable Visual Mappings 177 8.2.1 Mapping Composition Cases 178 8.2.2 Selecting a Context 180 8.2.3 Using the Same Graphic Relation Multiple Times 181 8.3 Prototype P1 (TopBraid-Composer-based) 182 8.4 Prototype P2 (OntoWiki-based) 184 8.5 Prototype P3 (Java Implementation of RVL) 187 8.6 Lessons Learned from Prototypes & Future Work 190 8.6.1 Checking RVL Constraints and Visualisation Rules 190 8.6.2 A User Interface for Editing RVL Mappings 190 8.6.3 Graph Transformations with SPIN and SPARQL 1.1 Update 192 8.6.4 Selection and Filtering of Data 193 8.6.5 Interactivity and Incremental Processing 193 8.6.6 Rendering the Final Platform-Specific Code 196 9 Application 197 9.1 Coverage of Case Study Sketches and Necessary Features 198 9.2 Coverage of Visualisation Cases 201 9.3 Coverage of Requirements 205 9.4 Full Example 206 10 Conclusions 211 10.1 Contributions 211 10.2 Constructive Evaluation 212 10.3 Research Questions 213 10.4 Transfer to Other Models and Constraint Languages 213 10.5 Limitations 214 10.6 Future Work 214 Appendices 217 A Case Study Sketches 219 B VISO – Comparison of Visualisation Literature 229 C RVL 231 D RVL Example Mappings and Application 233 D.1 Listings of RVL Example Mappings as Required by Prototype P3 233 D.2 Features Required for Implementing all Sketches 235 D.3 JSON Format for Processing the AVM with D3 – Hierarchical Variant 238 Bibliography 238 List of Figures 251 List of Tables 254 List of Listings 257