SILVA, Leonira Morais da. Galactomanana de sementes de Cassia fistula: extração, caracterização e modificação. Um potêncial substituínte da galactomanana da Locusta bean. 2012. 90 f. Dissertação (mestrado em química)- Universidade Federal do Ceará, Fortaleza-CE, 2012. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-04-01T20:16:00Z No. of bitstreams: 1 2016_dis_lmsilva.pdf: 3372290 bytes, checksum: 7c141eef34955db9ed557b801296e729 (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-05-20T17:40:51Z (GMT) No. of bitstreams: 1 2016_dis_lmsilva.pdf: 3372290 bytes, checksum: 7c141eef34955db9ed557b801296e729 (MD5) / Made available in DSpace on 2016-05-20T17:40:51Z (GMT). No. of bitstreams: 1 2016_dis_lmsilva.pdf: 3372290 bytes, checksum: 7c141eef34955db9ed557b801296e729 (MD5) Previous issue date: 2012 / The demand for biodegradable materials extracted from renewable sources that have high performance and lower cost is increasingly growing. The galactomannan extracted from Cassia fistula seeds was characterized by several methodologies: Elemental Analysis; Protein content; Uronic acid content; Gel Permeation Chromatography (GPC); Intrinsic Viscosity; Rheological Studies;Turbidity; Thermogravimetry; Infrared and 1H, 13C NMR. The yield of the extraction was 26.5 % m/m. The values obtained for protein content, humidity and uronic acid content were: 2.5%, 11.9% and 3.6% respectively. The values of molar weight (Mw = 2.2 x106g/mol) and intrinsic viscosity (9.73 dL/g) found for GCF were close to those from locusta bean galactomannan. For galactomannan of locusta bean is the second galactomannan commercializes most in the world, for this reason a comparative between GCF was done andGLB. The rheological analysis showed that GCF solutions exhibited pseudoplastic behavior at concentrations higher than 1%. Thermogravimetry analysis for GCF showed three events: 1° related to water loss; 2° related to matter decomposition and the 3° related to loss of organic matter which is more resistant to degradation. The infrared spectrum showed characteristic bands for polysaccharide and the 1H and 13C NMR spectra showed galactomannan characteristic peaks. The ratio mannose/galactose of GCF determined by 1H NMR spectrum analysis was 3.2, value close to that one from locusta bean galactomannan. The GCF was modified by reacting with sodium periodate at several concentrations to obtain the modified polysaccharide with oxidation degrees of: 10%; 20%; 50%; 65% and 80% [(periodate molar rate/glycosidic unities) x100]. The yield values obtained for the reactions were around 70% w/w. The oxidated materials were characterized by Rheology; GPC and 1H ,13C NMR. It was observed a decrease of molar mass (Mw) of 2.3 x 106 g/mol (GCF) to 6.4 x 104 g/mol (GCFO10%). As the degree of oxidation increases there is a reduction of the molecular weight, confirming that there was a degradation of the polymeric chain by the oxidation reaction with sodium periodate. The rheological analysis for 1% (w/v) non-modified GCF solutions and of GCFOX’s showed a reduction of apparent viscosity with oxidation degree increase (at 596 s-1): of 60.0 mPa.s (GCF) to 14 and 1.7 mPa.s (GCFO10) and 80%, respectively. The 1H NMR spectra showed for samples until 20% a few signals on anomeric range, when compared with samples with oxidation degree higher than 50 %. The ratio Man/Gal increased from 3.2 for the original sample to 3.3 and 4.6 for those samples of 10 and 20%, respectively. That increase means that the oxidation takes place preferably at the galactose units. / A procura por materiais biodegradáveis, extraídos de fontes enováveis que apresentem alto desempenho e um menor custo é cada vez mais rescente. A galactomanana extraida das sementes de Cassia fistula (GCF) foi caracterizada através das análises elementar; teor de proteína; teor de ácido urônico;cromatografia de permeação em gel; viscosidade intrinseca; estudos reológicos; turbidez; análise termogravimétrica; espectroscopica na região do infravermelho e RMN de 1H e 13C. O rendimento da extração foi de 26,5 % em massa. Os valores de teor de proteína, umidade e ácido urônico obtidos foram de 2,5%, 11,9% e 3,6%, respectivamente. O valor da massa molar média (Mw) (2,2 x 106 g/mol) e viscosidade intríseca (9,73 dL/g) encontrado para GCF foram próximos aos valores encontrados para galactomanana de locusta bean. As análises reológicas mostraram que as soluções de GCF apresentam comportamento pseudoplático em concentrações acima de 1% m/v. Na análise termogravimétrica a amostra de GCF apresentou três eventos, o 1° referente à perda de água; o 2° evento referente à decomposição da matéria e o 3° evento referente à perda da matéria orgânica mais resistente a degradação. O espectro de infravermelho mostrou bandas características de polissacarídeo e os espectros de RMN de 1H e 13C mostraram picos característicos de galactomanana. A razão manose/galactose da GCF determinado pelo espectro de RMN de 1H foi de 3,2 razão próxima a galactomanana de locusta bean (GL). A galactomanana da locusta bean é a segunda galactomanana mais comercializada no mundo, por essa razão foi feito um comparativo entre a GCF e a GL. A GCF foi modificada através da reação com periodato de sódio em várias concentrações para obter o polissacarídeo modificado com graus de oxidação de 10%; 20%; 50%; 65% e 80% [(razão molar de periodato/unidades glicosídicas)x100]. Os valores obtidos do rendimento das reações foram em torno de 70% em massa. Os materiais oxidados foram caracterizados através das análises reológicas, por GPC e RMN 1H e 13C. Observa-se uma diminuição da massa molar (Mw) de 2,3 x 106 g/mol da GCF para 6,4 x 104 g/mol da galactomanana de Cassia fistula oxidada a 10% GCFO10%).A medida que aumenta o grau de oxidação ocorre uma redução da massa molar, confirmando que houve uma degradação da cadeia polimérica pela reação de oxidação com o periodato de sódio. A análise reológica de soluções 1% (m/v) de GCF não modificada e das galactomananas de Cassia fístula oxidadas (GCFOX’s) mostrou uma redução da viscosidade aparente com o aumento do grau de oxidação: de 60,0 mPa.s da GCF para 14 e 1,7 mPa.s da GCFO10% e GCFO80%, respectivamente. Os espectros de RMN 1H mostraram que para as amostras com o grau de oxidação até 20% aparecem poucos novos sinais na região de anomérico, quando comparados com as amostras com grau de oxidação acima de 50%. A razão Man/Gal aumenta de 3,2 da amostra original para 3,3 e 4,6 nas amostras de 10 e 20%, respectivamente. Esse aumento indica que a oxidação ocorre preferencialmente nas unidades de galactose.

Several types of insect cuticle contain enzymes catalyzing the formation ofof adducts between N-acetyldopamine (NADA) and N-acetylhistidine (NAH). Two such adducts, NAH-NADA-I and NAH NADA-II, have been isolated and their structures determined. In one of the adducts the link connecting the two residues occurs between the I-position (ß-position) in the NADA side chain and the 1-N atom (τ-N) in the imidazole ring of histidine. Diphenoloxidase activity alone is not sufficient for formation of this adduct, whereas extracts containing both diphenoloxidase and o-quinone-p-quinone methide isomerase activities catalyze the coupling reaction. The adduct consists of a mixture of two diastereomers and they are presumably formed by spontaneous reaction between enzymatically produced NADA-p-quinone methide and N-acetylhistidine. The other adduct has been identified as a ring addition product of N-acetylhistidine and NADA. In contrast to the former adduct it can be formed by incubation of the two substrates with mushroom tyrosinase alone. An adduct between N-acetylhistidine and the benzodioxan-type NADA-dimer is produced in vitro, when the N-acetylhistidine-NADA adduct is incubated with NADA and locust cuticle containing a 1,2-dehydro-NADA generating enzyme system. Trimeric NADA-polymerization products of the substituted benzodioxan-type have been obtained from in vivo sclerotized locust cuticle, confirming the ability of cuticle to produce NADA-oligomers. The results indicate that some insect cuticles contain enzymes promoting linkage of oxidized NADA to histidine residues. It is suggested that histidine residues in the cuticular proteins can serve as acceptors for oxidized NADA and that further addition of NADA-residues to the phenolic groups of bound NADA can occur, resulting in formation of protein-linked NADA-oligomers. The coupling reactions identified may be an important step in natural cuticular sclerotization.

There is a thermal range for the operation of neural circuits beyond which nervous system function is compromised. Poikilotherms are particularly vulnerable to thermal stress, since their body temperature can fluctuate with ambient temperature. Animals that experience frequent hyperthermia have various coping mechanisms such as the thermoprotective effect of a prior exposure to sublethal temperatures (heat shock response). The molecular mechanisms of this thermoprotection have yet to be understood. This project studies the changes in protein expression in the nervous system of gregarious Locusta migratoria subjected to heat shock. For this purpose, proteins were extracted from metathoracic ganglia (MTG) by different methods and a proteomic map was subsequently obtained by 2-D gel electrophoresis which was compared between control (CON) and heat-shocked (HS) animals. Additionally, the localization pattern of Hsp70 was studied in the MTG of CON and HS gregarious locusts. Although 2-D gels showed changes in the amount of different isoforms of ATP-synthase β, the overall amount of this protein subunit was found to be unchanged. My experiments also revealed no significant change in the distribution of Hsp70 in the MTG of locusts caused by HS. However, new findings show that this protein is constitutively expressed at higher levels in perineurium, glia and tracheal cells than in neurons. In separate experiments, isolated locusts were also examined in order to measure any stress-associated increase of Hsp70 in the tissues of animals not previously exposed to crowding pressure. Quantitative western blots did not show a consistent change of the Hsp70 level in the MTG of isolated locusts following heat shock. Results of my research suggest that the change in the protein profile of the metathoracic ganglion following heat shock, if it exists, is subtle or occurs in very low-abundance proteins whose monitoring requires the application of special techniques. Alternatively, the thermoprotective effect of heat shock on the nervous system might be promoted through other pathways which can change the protein activity at the post-translational level and may work independently from protein synthesis. / Thesis (Master, Biology) -- Queen's University, 2009-03-20 12:28:32.962

Most vertebrates suffer permanent damage after minutes of anoxia. Many insects however, have part of their life cycle in anoxia or constant hypoxia, such as during their egg-hatching phase, by living as deep burrowers, or at high altitudes. Insects are able to survive in anoxia from hours to days, or even months by developing various strategies through evolution. For example, the locusts (Locusta migratoria) enter a reversible coma during anoxia that is associated with an arrest of ventilation, and a reinitiation of ventilation when returned to normoxia. This coma is correlated with a surge in the concentration of extracellular potassium ions ([K+]o), and recovery from this reversible coma is dependent on re-establishing the functional [K+]o. Prior exposure to a sublethal heatshock (HS)-preconditioning grants locusts a temporary resilience to anoxia; however, the molecular mechanisms of this protection are still unclear. This project investigated the effects of HS-preconditioning on locusts’ ventilation, the total enzymatic activity of the Na+/K+-ATPase, as well as its distribution within the metathoracic ganglion and tested the hypothesis that HS-preconditioning alters locusts’ ventilation and increases the totally Na+/K+-ATPase activity and its concentration within neuronal membranes. I recorded electromyograms of locusts’ ventilatory motor patterns in the presence and absence of anoxic coma by placing a copper wire electrode on ventilatory muscles 161 or 173 in control and HS-preconditioned animals. In addition, I studied the enzymatic activity of the Na+/K+-ATPase using a pyruvate kinase/lactate dehydrogenase assay and the localization of the Na+/K+-ATPase using immunohistochemistry in control and HS-preconditioned locusts at different stages of coma. I found that the ventilatory cycle period was decreased and the ventilatory muscle burst duration was increased after recovery from anoxic coma in HS-preconditioned locusts. I also found that anoxia did not affect the activity or the localization of the Na+/K+-ATPase. However, HS-preconditioning increased the total activity of the Na+/K+-ATPase and the localization of the Na+/K+-ATPase within the neuronal membranes. From this project, I concluded that HSpreconditioning affected locusts’ ventilatory motor pattern after recover from anoxia and increased the total activity and the neuronal membrane localization of the Na+/K+-ATPase. / Thesis (Master, Biology) -- Queen's University, 2011-09-26 13:14:48.472

The FGLa/ASTs are one family of allatostatin peptides and share an amidated C-terminal sequence (FGL-amide). The inhibitory effect of FGLa/ASTs on juvenile hormone (JH) biosynthesis in Diploptera punctata led to their discovery, but there is a lack of allatostatic function across most insect species that suggests this function may not be their primary role. Rather, the FGLa/ASTs are implicated as brain/gut peptides, modulating gut physiology. This thesis demonstrates the pleiotropic nature of FGLa/ASTs in Locusta migratoria and emphasizes the role of FGLa/ASTs as brain/gut peptides involved in homeostatic processes. FGLa/AST-like immunoreactivity (FLI) is associated with the corpus cardiacum (CC) and corpus allatum (CA). FGLa/ASTs increase adipokinetic hormone release from the CC and alter JH biosynthesis from the CA, suggesting roles in energy utilization and in growth and metamorphosis. Each region of the gut exhibits FLI. The gut is dually innervated: neurons in the abdominal ganglia of the central nervous system (CNS) innervate the posterior gut and some contain FLI, while neurons within the stomatogastric nervous system (STNS) that innervate the anterior gut do not seem to contain FLI, indicating that source of FLI on the gut are cells within the CNS, which may release FGLa/ASTs at the gut to alter aspects of gut physiology. FGLa/ASTs are involved in peristalsis, neural control of foregut contractions, and ileal K+ transport. In particular, FGLa/ASTs inhibit contractions of each gut region and also modulate the rhythmic motor output of a central pattern generator within the ventricular ganglion of the STNS. FGLa/ASTs also inhibit ileal K+ efflux, suggesting a diuretic action and implicating FGLa/ASTs in fluid and ion homeostasis. This work provides a comprehensive picture of how FGLa/ASTs play an integral role in nutrient processing, energy mobilization, and growth and metamorphosis to contribute to the overall maintenance of homeostasis. This reinforces the role of FGLa/ASTs as brain/gut peptides and emphasizes their involvement in the flexibility of nervous communication and integration of the endocrine system with the CNS to achieve homeostasis.

The FGLa/ASTs are one family of allatostatin peptides and share an amidated C-terminal sequence (FGL-amide). The inhibitory effect of FGLa/ASTs on juvenile hormone (JH) biosynthesis in Diploptera punctata led to their discovery, but there is a lack of allatostatic function across most insect species that suggests this function may not be their primary role. Rather, the FGLa/ASTs are implicated as brain/gut peptides, modulating gut physiology. This thesis demonstrates the pleiotropic nature of FGLa/ASTs in Locusta migratoria and emphasizes the role of FGLa/ASTs as brain/gut peptides involved in homeostatic processes. FGLa/AST-like immunoreactivity (FLI) is associated with the corpus cardiacum (CC) and corpus allatum (CA). FGLa/ASTs increase adipokinetic hormone release from the CC and alter JH biosynthesis from the CA, suggesting roles in energy utilization and in growth and metamorphosis. Each region of the gut exhibits FLI. The gut is dually innervated: neurons in the abdominal ganglia of the central nervous system (CNS) innervate the posterior gut and some contain FLI, while neurons within the stomatogastric nervous system (STNS) that innervate the anterior gut do not seem to contain FLI, indicating that source of FLI on the gut are cells within the CNS, which may release FGLa/ASTs at the gut to alter aspects of gut physiology. FGLa/ASTs are involved in peristalsis, neural control of foregut contractions, and ileal K+ transport. In particular, FGLa/ASTs inhibit contractions of each gut region and also modulate the rhythmic motor output of a central pattern generator within the ventricular ganglion of the STNS. FGLa/ASTs also inhibit ileal K+ efflux, suggesting a diuretic action and implicating FGLa/ASTs in fluid and ion homeostasis. This work provides a comprehensive picture of how FGLa/ASTs play an integral role in nutrient processing, energy mobilization, and growth and metamorphosis to contribute to the overall maintenance of homeostasis. This reinforces the role of FGLa/ASTs as brain/gut peptides and emphasizes their involvement in the flexibility of nervous communication and integration of the endocrine system with the CNS to achieve homeostasis.

Oxidative stress is caused by an imbalance between oxidants and antioxidants. Oxidative stress generated by reactive oxygen species (ROS) or reactive nitrogen species (RNS) occurs when protection of antioxidants fails or when an amount of ROS is too high. Telomeres, regions of repetitive nucleotide sequences at the end of chromosomes, are especially sensitive to oxidative stress because they contain a lot of guanine which is often oxidised. Antioxidants play an important role in protection against oxidative stress. In this thesis I analysed the effect of oxidative stress caused by paraquat on activity of antioxidant enzymes (catalase and superoxide dismutase) and telomere length in Locusta migratoria. I also studied differences in telomere length between locusts of various development stages and telomerase activity in locusts and other Orthoptera.

No description available.

Das Neuron ist das zentrale Element in der Informationsverarbeitung im Nervensystem. In dieser Arbeit werden verschiedene Aspekte der Spikegenerierung sowohl theoretisch als auch experimentell untersucht. Phasen-Rotatoren verschiedener Komplexität werden zur Vorhersage von Spikezeitpunkten vorgestellt. Die Kennlinie eines Neurons wird dabei als wichtiger Parameter für diese Modelle verwendet, damit diese leicht auf echte Neurone anwendbar sind. Die Phasenantwortkurve als ein zweiter wichtiger Aspekt der Spikedynamik wird zur Erweiterung der Modelle verwendet. Solange ein Neuron in seinem überschwelligen Bereich gereizt wird, erweisen sich die Phasenrotatoren als gute Beschreibung des Spikeverhaltens. Es wird jedoch gezeigt, daß bei einer Stimulierung mit Strömen, die um die Schwelle des Neurons herum fluktuieren, diese Modelle, genauso wie alle anderen eindimensionalen Modelle einschließlich des Intergrate-and-fire Neurons, versagen. Feuerraten Adaptation kann in vielen Neuronen beobachtet werden. Es wird ein allgemeines phänomenologisches Modell für die Feuerrate adaptierender Neurone aus den Eigenschaften verschiedene Ionenströme, die Adaptation verursachen, hergeleitet. Dieses Modell ist durch die Kennlinien und einer Adaptations-Zeitkonstanten vollständig definiert. Mit Hilfe des Modells können die Eigenschaften der Adaptation als Hochpassfilter quantifiziert werden. Weiterhin wird die Rolle der Adaptation bei der Unterdrückung von Hintergrundrauschen diskutiert. Sowohl die Phasenrotatoren als auch das Adaptationsmodell werden an auditorischen Rezeptorzellen der Wanderheuschrecke und dem AN1, ein primäres auditorisches Interneuron der Grille {Teleogryllus oceanicus}, getestet. In beiden Fällen stimmen die Modelle gut mit den experimentelle Daten überein. Es wird mit Hilfe der Modelle gezeigt, daß Adaptation in den Rezeptorzellen durch Ionenströme des Spikegenerators verursacht wird, während in dem Interneuron der Eingang schon adaptatiert. Zusätzlich wird der Einfluß der Feuerraten-Adaptation auf die Gesangserkennung analysiert. / The single neuron is the basic element of information processing in nervous systems. In this thesis several properties of the dynamics of the generation of spikes are investigated theoretically as well as experimentally. Phase oscillators of different complexity are introduced as models to predict the timing of spikes. The neuron's intensity-response curve is used as a basic parameter in these models to make them easily applicable to real neurons. As a second important aspect of the spiking dynamics, the neuron's phase-resetting curve is used to extend the models. The phase oscillators turn out to be a good approximation of the spiking behavior of a neuron as long as it is stimulated in its super-threshold regime. However, it is shown by comparison with conductance-based models that these models, as well as all other one-dimensional models including the common integrate-and-fire model, fail, if the neuron is stimulated with currents fluctuating around its threshold. Spike-frequency adaptation is a common feature of many neurons. For various ionic currents, as a possible reason for adaptation, a general phenomenological model for the firing rate of adapting neurons is derived from their biophysical properties. This model is defined by the neuron's intensity-response curves and an adaptation time-constant. By means of this model the high-pass properties of spike-frequency adaptation can be quantified. Also the role of adaptation in supression of background noise is discussed. Both the phase oscillators and the adaptation-model are tested on auditory receptor neurons of locusts and the AN1, a primary auditory interneuron of the cricket {Teleogryllus oceanicus}. In both cases the models are in good agreement with the experimental data. By means of the models it is shown that adaptation in the receptor neurons is caused by ionic currents of the spike generator while in the interneuron it is the input which is already adapting. In addition, the influence of spike-frequency adaptation on the recognition of courtship songs is analysed.

No description available.