"April 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 158-181). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

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Thesis (PhD (Botany and Zoology))--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Insect societies utilize advanced chemical communication systems to organize many aspects of their social life, which among others, include reproduction, thus maintaining colony homeostasis. The queen pheromone complex (QMP), dominated by (E)-9-keto-2-decenoic acid (9ODA) is of integral importance in regulating worker reproductive development. Unique characteristics, associated with reproductive dominance, enabled the successful establishment of Apis mellifera capensis workers as social parasites (or pseudoqueens) in colonies of the neighbouring A. m. scutellata. This suggested that producing a queenlike pheromonal bouquet is one of the proximate factors in their success. In this study we attempted to address the pheromone communication dilemma by investigating whether the phenotypic expression of mandibular gland signals in honeybee workers are under genetic and/or environmental influence. It was hypothesized that the mandibular gland profiles of queens and workers may be closely correlated to specific genotypes in the colony. However, different ageing and rearing environments (social context) can ultimately influence gene expression with respect to mandibular gland signals, highlighting the fact that environmental influences are not necessarily non-significant. In our experiments, both environmental/social conditions and genotypes of our test individuals were manipulated. The capensis workers used in our experiment from their native range (Western Cape area are refered to as native workers, while capensis parasitic workers, from the clonal parasitic lineage, were obtained from the Gauteng area. A. m. scutellata workers were obtained from their native range, north of the hybrid zone. Both native and parasitic workers showed the potential to become reproductively active, but the rapid pheromonal development of parasitic workers placed them at a reproductive advantage. Parasitic workers started producing low levels of 9HDA, the precursor to the queen substance 9ODA, between 12-24 hrs, while native workers only did so after 24 hrs. Despite this, rapid signal development did not culminate in the parasitic clones always pheromonally out-competing native workers. Withinin groups of native workers and a single clonal parasitic worker, the mandibular gland profiles of most workers were dominated by 9ODA and 9HDA (> 80% of extracts) with only 43% of the single parasitic workers producing higher amounts of 9ODA than native workers. Mandibular gland pheromone profiles converged in groups of workers sharing a greater proportion of genes, providing support for a link to genotypic affects. Workers that were 75 – 99% related diverged significantly from groups with lower levels of relatedness was largely due to the presences of 9ODA (Spearman’s rank correlation r = 0.66, p < 0.0001). Despite the tendency for signal to convergence in groups of closer relatedness a considerable amount of signal variability was also observed under varying social conditions. Workers originating from a single capensis queen but aged under queenright and queenless conditions had very distinct mandibular gland profiles (Wilks’ lambda λ = 0.118, χ2 = 331.002, p < 0.0001). This variability was thus a result of the social environment that the workers were exposed to. The physiological traits, namely mandibular gland pheromone production, linked to reproductive potential in honeybee workers seem to be determined by a combination of environmental and genetic factors. Queen mandibular gland pheromone biosynthesis is genetically predisposed in certain workers however the final oxidation step to 9ODA is strongly influenced by the social environment. The signal plasticity observed in this study is adaptive and assists workers to realize their reproductive potential. / AFRIKAANSE OPSOMMING: Insek gemeenskappe gebruik gevorderde chemiese kommunikasie sisteme om verskeie aspekte van sosiale lewe, onder andere reproduksie, te organiseer en sodoende word korf homeostasis handhaaf. Die feromoon kompleks van die koninginby, wat hoofsaaklik uit (E)-9-keto-2-decenoic acid (9ODA) bestaan speel ʼn belangrike rol in die regulering van reproduksie in heuningby werkers. Die suksesvolle vestiging van Apis mellifera capensis werkers as sosiale parasiete (pseudo koninginne) in die korwe van die naburige A. m. scutellata, is bewerkstellig deur hul unieke kenmerke, wat met reproduktiewe oorheersing verband hou. Dit suggereer dat die produksie van ʼn tipiese koningin feromoon sein een van verskeie beduidende faktore is in capensis werkers se sukses. In hierdie studie het ons die dilemma van feromoon kommunikasie probeer aanspreek deur te ondersoek of die fenotipiese uitdrukking van seine van die mandibulêre kliere deur genetiese en/of omgewings faktore beïnvloed word. Die hipotese was dat die mandibulêre klier profiele van koninginne en werkers korreleer met spesifieke genotipes in die korf. Die verskillende omgewings waarin werkers groot gemaak word en verouder (sosiale konteks), kan uiteindelik die uitdrukking van gene, raakende mandibulêre kliere, beïnvloed. Dit beklemtoon die feit dat omgewings faktore nie noodwendig onbeduidend is nie. Beide omgewings/sosiale toestande and genotipes van toets individue is in ons eksperimente gemanipuleer. Die capensis werkers afkomstig uit hul natuurlike habitat (Weskaap area) wat in ons eksperimente gebruik is word na verwys as inboorling werkers, terwyl parasitiese capensis werkers, van klonies parasitiese afkoms, vanuit die Gauteng area verkry is. A. m. scutellata werkers was vanuit hul natuurlike habitat, noord van die, hybried sone, verkry. Beide inboorling en parasitise werkers het die potensiaal getoon om reproduktief aktief te word, maar versnelde feromoon ontwikkeling van parasite werkers het hulle ʼn reproduktiewe voordeel gegee. Parasiet werkers het reeds lae hoeveelhede 9HDA, die voorganger van 9ODA, begin produseer tussen 12 – 24 uur, terwyl inboorling werkers produksie eers na 24 uur begin het. Ten spyte van die versnelde ontwikkeling in parasiet werkers het dit nie gelei daartoe dat kloniese parasiete altyd feromonies die oorhand oor inboorling werkers gekry het nie. In groepe bestaande uit inboorling werkers en ʼn enkele parasite werker, was die mandibulêre klier profiele altyd deur 9ODA en 9HDA (> 80% van ekstrakte) gedomineer. Slegs 43% van parasite werkers het groter hoeveelhede 9ODA as inboorling werkers geproduseer. In groepe werkers, wat ʼn groter proporsie gene in gemeen gehad het, het mandibulêre klier profiele konvergeer. Dit ondersteun die bestaan van ʼn verband met genotipiese invloed. Werkers van 75 – 99% verwantskap het beduidend verskil van groepe met laer verwantskapsvlakke, hoofsaaklik as gevolg van die teenwoordigheid van 9ODA (Spearman’s rank korrelasie r = 0.66, p < 0.0001). Ten spyte van die konvergerende neiging van profiele, van meer verwante groepe, was aansienlike veranderlikheid onder verskillende sosiale toestande waargeneem. Werkers, afkomstig vanaf ʼn enkele capensis koninginby, maar òf in die teenwoordigheid òf afwesigheid van ʼn koningin verouder is, het baie kenmerkende mandibulêre klier profiele getoon (Wilks’ lambda λ = 0.118, χ2 = 331.002, p < 0.0001). Die veranderlikheid was dus ʼn gevolg van die sosiale omgewing waaraan die werkers blootgestel was. Dit blyk asof die fisiologiese kenmerke wat met reproduksie potensiaal in heuningbye verband hou, naamlik mandibulêre klier feromoon produksie, deur ʼn kombinasie van genetiese – en omgewings faktore beïnvloed word. Sekere werkers is meer geneig tot die biosintese van koningin mandibulêre klier feromoon as gevolg van hul genetika, terwyl die finale oksidasie na 9ODA onder sterk omgewings invloed is. Die plastisiteit in mandibulêre seine waargeneem in hierdie studie, is aanpasbaar en help werkers om hul reproduksie potensiaal te bereik.

Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Please refer to fulltext for abstract / AFRIKAANSE OPSOMMING: Sien asb volteks vir opsomming

Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Bontebok, Damaliscus pygargus pygargus, formerly classified as D. dorcas dorcas, are territorial animals with interdigital glands between the toes of the forelegs. Males regularly defecate on dung heaps, on which they often lie, to communicate with other members of their species. They also communicate by means of visual displays, scent marking and occasionally with scraping or pawing of dung heaps. It is assumed that scent marking with the interdigital secretion serves to define territories frequented by these antelope. These glands secrete a complex mixture of volatile and non-volatile compounds and the volatile compounds in the secretion serve as a chemical signal for other bontebok. It has been suggested that the interdigital secretion is not produced in its final composition by the interdigital gland alone, but that microbial activity is responsible for many of the compounds present in the secretion. In general, many compounds can be attributed to the by-products of microbial hydrolysis of triglycerides, a common characteristic of sebum. It is well documented that micro-organisms inhabit the deep recesses of sebaceous glands and the presence of micro-organisms has been found to be consistent in all antelope exocrine glandular areas. This study involved the chemical characterisation of the volatile metabolites produced in vitro by micro-organisms from the interdigital cavity of the bontebok. Various comparative studies were made, one of which was comparison of the metabolites produced by the individual microbial species as well as the total community of bacteria incubated in different media. A comparison of the compounds identified in the interdigital secretion and the metabolites produced by the micro-organisms in the different media was also made. The volatile metabolite extracts of the individual bacterial species and of the total community were chemically characterised by low-resolution gas chromatography-mass spectroscopy. Classes of compounds identified from the volatile metabolite extracts include: • Acids - Aliphatic (saturated and unsaturated) • Alcohols - Aliphatic (saturated and unsaturated) • Aldehydes - Aliphatic (saturated and unsaturated) • Aromatic compounds • Ketones - Aliphatic (saturated and unsaturated) • Pyrazines • Dimethyldisulphide • Squalene and cholesterol Several qualitative differences were found between the compounds identified in the volatile metabolite extracts of the micro-organisms when incubated in tryptic soy broth (TSB) and minimal salt medium (MSM). In particular, when the microbes were incubated in TSB medium a number of pyrazines were found that were not present when utilising MSM as a medium. Additional qualitative differences were found between the compounds identified in the metabolite extracts of the individual bacterial species and the total community of bacteria, when incubated in both TSB and MSM media. A comparison of the interdigital secretion and the metabolite extracts of the microbial communities incubated in TSB and MSM revealed that many compounds produced in MSM corresponded to the compounds identified in the interdigital secretion. These corresponding compounds were found to be saturated and unsaturated acids, aldehydes and squalene. Furthermore, there was only one corresponding compound in the case of TSB as medium. / AFRIKAANSE OPSOMMING: Die bontebok, Damaliscus pygargus pygargus, voorheen geklassifiseer as D. dorcas dorcas, is 'n territoriale dier met interdigitale kliere tussen die kloutjies van die voorpote. Ramme ontlas gereeld op mishope, waarop hulle dikwels lê, om met ander lede van die spesie te kommunikeer. Hulle kommunikeer ook deur middel van visuele seine, reukmerking en soms deur mishope met die voorpote te kap of te skraap. Reukmerking met die interdigitale afskeiding dien klaarblyklik om gebiede wat deur hierdie diere bewoon word, af te baken. Die interdigitale kliere skei 'n komplekse mengsel van vlugtige en nie-vlugtige verbindings af en die vlugtige verbindings dien as chemiese sein vir ander bontebokke. Die vermoede bestaan dat die interdigitale klier nie alleen verantwoordelik is vir die finale samestelling van die interdigitale afskeiding nie, maar dat mikrobiese aktiwiteit bydra tot die produksie van baie van die verbindings wat in die afskeiding aanwesig is. Sekere verbindings kan in die algemeen toegeskryf word aan die vorming van die neweprodukte van mikrobiese hidrolise van trigliseriede, 'n algemene eienskap van sebum. Dit is bekend dat die diep holtes van vetkliere 'n goeie teelaarde is vir mikroorganismes en daar is gevind dat mikroorganismes feitlik deurgaans voorkom in alle anteloop eksokriene klierareas. Hierdie studie behels die chemiese karakterisering van die vlugtige metaboliete wat in vitro deur mikroorganismes van die interdigitale klierholte van die bontebok geproduseer word. Verskeie vergelykende studies is uitgevoer waarvan een die vergelyking was van die metaboliete wat deur die individuele mikrobiese spesies sowel as die totale gemeenskap van bakterieë geproduseer word tydens inkubasie in verskillende media. Vergelyking van die verbindings wat in die interdigitale afskeiding geïdentifiseer is met die metaboliete wat in verskillende media geproduseer is, het ook deel van die studie uitgemaak. Die vlugtige metaboliet ekstrakte van die individuele bakteriese spesies en van die totale gemeenskap is chemies gekarakteriseer deur middel van laeresolusie gaschromatografie-massaspektrometrie. Die volgende groepe verbindings is onder andere in die vlugtige metaboliet ekstrakte geïdentifiseer: • Sure - Alifaties (versadig en onversadig) • Alkohole - Alifaties (versadig en onversadig) • Aldehiede - Alifaties (versadig en onversadig) • Aromatiese verbindings • Ketone - Alifaties (versadig en onversadig) • Pirasiene • Dimetieldisulfied • Skwaleen en cholesterol Verskeie kwalitatiewe verskille is gevind tussen die verbindings wat geïdentifiseer is in die vlugtige metaboliet ekstrakte van die mikroorganismes onderskeidelik in TSB medium en MSM geïnkubeer. Opvallend was byvoorbeeld die voorkoms van pirasiene in gevalle waar mikroorganismes in TSB medium geïnkubeer is, terwyl hierdie groep verbindings afwesig was wanneer MSM gebruik is. Onderlinge kwalitatiewe verskille is ook gevind tussen die verbindings wat geïdentifiseer is in die metaboliet ekstrakte van die individuele bakteriese spesies en die totale gemeenskap van bakterieë, wanneer in TSB medium sowel as in MSM geïnkubeer is. Vergelyking van die verbindings in die interdigitale afskeiding en in die metaboliet ekstrakte van die mikrobiese gemeenskappe, het getoon dat 'n aantal verbindings wat in MSM geproduseer is, ooreenstem met verbindings wat in die interdigitale afskeiding geïdentifiseer is. Daar is gevind dat hierdie verbindings versadigde en onversadigde sure en aldehiede en skwaleen is. Met TSB as medium was daar slegs een ooreenstemmende verbinding.

published_or_final_version / abstract / Anatomy / Doctoral / Doctor of Philosophy

Previous studies have focused on gastric dysmotility and delayed emptying in diabetes mellitus. There is little information about the effects of hyperglycemia on colonic motility and secretion. 5-HT was reported to mediate contractile activity by activating receptors on both enteric neurons and smooth muscle cells. The aim of this study was to investigate and compare the effects of 5-HT on circular contractile activity coordinated with secretion in streptozocin-induced diabetic and non-diabetic rats. Sonomicrometry and voltage clamping techniques were used to measure motility and secretion simultaneously in isolated whole thickness colonic sheets. Male Sprague Dawley rats were injected with streptozocin (65 mg/kg body weight) in 0.1 M sodium citrate buffer, into the tail veins. Glucose levels of 300-400 mg/dl and above were achieved. The control rats were injected with the same volumes of vehicle (0.1 M sodium citrate buffer). Animals were sacrificed 10-12 days following the induction of hyperglycemia. Flat sheets of colon were mounted serosal side up in Ussing chambers. 1 mm piezocrystals were glued to the serosal surface 4-5 mm apart to measure circular contractions as decrease in inter-crystal distances (ICD). Voltage-clamping the tissues at 0 mV was used ix to measure short circuit current (Isc), indicative of chloride secretion. In diabetic rats 50 gM 5-HT caused mean amplitude of contractions of 174 ± 26 gm (n=4), which was significantly reduced as compared to the response in non-diabetic rats of 970 + 243 gm (n=4; p<0.05). The secretory response in diabetic rats paralleled the reduction in ICD (diabetic: 23 +1 gA/cm2, controls: 57 + 18 gA/cm2). Neural blockade with 0.1 gM TTX revealed a decreased myogenic contractile activity in diabetic rats. The mean amplitude of contractions after TTX in diabetic rats was 162 ± 45 gm verses controls of 612 ± 86 gm. These results suggest that the reduction of the 5-HT contractile response in diabetic rats may be a composite of direct effects on the smooth muscle as well as indirect effects on the neurons. / Department of Physiology and Health Science

A fibropapilomatose é uma neoplasia caracterizada pela formação de múltiplos tumores que acomete, mais frequentemente, a espécie de tartaruga marinha Chelonia mydas. Estudos recentes apontam o Chelonid herpesvirus 5 (ChHV5) como o provável agente etiológico dessa doença, embora a associação com ambientes antropogenicamente alterados parecem contribuir para o desenvolvimento da doença. Nesse estudo, biópsias de tumores e secreções de tartarugas verdes capturadas no litoral do Estado de São Paulo, Brasil, foram submetidas a análises histológicas e moleculares visando detectar e caracterizar ChHV5. Em 45,5 % dos casos, os achados histopatológicos revelaram células epiteliais balonizantes com corpúsculos de inclusão intranucleares. ChHV5 foram detectados nas biópsias de pele e oculares dos animais e em secreções oculares e saliva por PCR. A análise das sequências parciais do gene da polimerase do ChHV5 detectadas revelou duas sequências gênicas distintas entre si. A análise filogenética indicou que as amostras brasileiras são similares às amostras de ChHV5 do grupo filogeográfico do Atlântico, compartilhando o mesmo clado que amostras provenientes do Golfo da Guiné e de Porto Rico, sugerindo um possível fluxo dos vírus entre essas três regiões. / Fibropapillomatosis is a neoplastic disease characterized by the formation of multiple tumors affecting different species of sea turtles and, most often, Chelonia mydas. Recent studies indicate that Chelonid herpesvirus 5 (ChHV5) is the etiological agent of this disease, though its association with anthropogenically altered environments also appears to contribute to disease expression and tumor formation. In this study, tumor biopsy and secretions from green turtles captured off the coast of São Paulo State, Brazil, were used in histological and molecular analyses to detect and characterize ChHV5. In 45.5 % of cases, the tumor histopathological findings revealed ballooning degeneration with intranuclear inclusion bodies. ChHV5 was detected using polymerase chain reaction on the animals skin, ocular tumor biopsies, and ocular and oral secretions. The analysis of the detected ChHV5 sequences revealed two distinct genetic sequences together. Phylogenetic analysis indicated that Brazilian samples were similar to ChHV5 samples described for the Atlantic phylogeographic group and are therefore part of the same clade as the Gulf of Guinea and Puerto Rico samples. This similarity suggests a possible flow of the virus between these three regions.

Both VEGF and its receptor proteins were localized by immunostaining technique in the luminal epithelium, smooth muscle cells and blood vessels within the oviduct. Moreover, by means of semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) techniques, it has been demonstrated that mRNA of VEGF and its receptors in both healthy and diseased oviduct is expressed preferentially at the time and place where the amount of oviduct fluid is prominent. This supports the notion that VEGF may be a regulator of oviductal secretion. This thesis has consistently demonstrated a modulation pattern of flt-1 expression that is similar to its ligand VEGF in both physiological and pathological conditions. This suggests that flt-1 may be the main receptor responsible for the action of VEGF in the oviduct. As illustrated in both the in-vivo and in-vitro models, the expression of VEGF and flt-1 in the human oviduct is stimulated directly by gonadotropins without the influence of ovarian sex hormones. / Increased knowledge on the regulatory mechanisms of oviductal fluid formation, the first environment that human embryos are exposed to, will be valuable from the clinical management point of view. / Oviductal fluid is a complex mixture of plasma-derived constituents and proteins synthesized by the oviduct epithelium. It has been postulated that vascular endothelial growth factor (VEGF), a known permeability promoter, may be an important regulator of oviductal fluid secretion by stimulating vascular permeability and so serum transudation. However, little is known about the expression of VEGF in the human oviduct. This thesis investigated the modulation of VEGF and its receptors (flt-1 and KDR) in the healthy oviducts, from fertile women undergoing tubal sterilization for unwanted fertility or hysterectomy for benign gynecological conditions, as well as in the hydrosalpinges from sterile women undergoing salpingectomy before the treatment of in-vitro fertilization and embryo transfer. / Lam Po Mui. / Adviser: Christopher J. Haines. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (M.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 147-179). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.

Made available in DSpace on 2014-06-11T19:30:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2003Bitstream added on 2014-06-13T18:41:02Z : No. of bitstreams: 1 kuczynski_lb_dr_botfm.pdf: 2548402 bytes, checksum: ff27d7551d7a419be61cd511e4dedf1e (MD5) / Nas ressecções pancreáticas por pancreatite crônica, o pâncreas remanescente poderá sofrer novos surtos de pancreatite, em gravidade variável. Nas ressecções por tumores ou pancreatite, a mais comum complicação é a fístula pancreática, com suas conseqüentes morbidade e mortalidade. Nos transplantes pancreáticos, a drenagem da parte exócrina do enxerto para o intestino ou para a bexiga, além das peculiaridades técnicas da execução, não é isenta de diversas complicações. Visando evitar ou atenuar tais conseqüências e simplificar a técnica cirúrgica, têm sido usadas outras abordagens para o tratamento do coto/enxerto pancreático: drenagem livre das secreções com o ducto pancreático aberto, ligadura ductal e oclusão do ducto com polímeros. O propósito de nossa investigação foi estudar os efeitos clínicos, laboratoriais e histopatológicos destes procedimentos sobre os componentes endócrino e exócrino do pâncreas em coelhos... / After pancreatic ressections due to chronic pancreatitis the remnant pancreas can lead to new outbreaks of pancreatitis in variable degrees of severity. After the resections by tumors or pancreatitis, the most common complication are the pancreatic fistulas with their resultant morbidity and mortality. In the pancreas transplantation the bowel or bladder drainage of the exocrine part of the graft, beyond the technical peculiarities of the execution, is not exempt of several complications. In order to avoid or reduce such consequences and trying to simplify the surgical technique, there have been used other approaches for the treatment of the pancreatic stump/graft: free drainage of the secretions with the duct left open, ductal ligature and duct occlusion with polymers. The proposal of our investigation was to study the clinical, laboratorial and histopathological effects of these procedures in the endocrine and exocrine compounds of the rabbit pancreas... (Complete abstract, click electronic address below)