The Mexican tetra, Astyanax mexicanus, exists as two morphs of a single species, a sighted surface morph and a blind cavefish. In addition to eye regression, cavefish have an increased number of taste buds, maxillary teeth and have an altered craniofacial skeleton. I investigated the effect the lens has on the development of the surrounding skull by ablating the lens over early ontogeny. This unique long-term study sheds light on how early embryonic manipulations on the eye can affect the shape of the adult skull. The effects of lens ablation were analyzed using landmark based morphometric analyzes. Morphometric analyzes indicate that there is a significant difference in the shape of the supraorbital bone and suborbital bones four through six. These bones expand into the eye orbit exhibiting variability in their shape. Interestingly, the number of caudal teeth on the lower jaw is also affected by lens ablation. I compared these findings between morphs and across two teleost species. I conducted lens removal in the surface fish to determine if it would produce a cavefish phenotype. Lens removal in the surface fish only partially results in a cavefish phenotype, indicating that lens loss is not solely responsible for the phenotypic differences between the two morphs. The effects of lens removal were then compared in the Mexican tetra and zebrafish. Surprisingly, the results indicate that the same bones are variable in shape in both species, indicating that the variability of these bones is conserved across species. Finally, I compared laser lens damage and full lens removal, to investigate the capacity for both lens regeneration and healing in the Mexican tetra. Together, the lens healing and regeneration studies indicate that lens absence in early development does not influence the shape of the skull. Lens absence during later development influences the mechanical forces in the skull resulting in the bones of the orbital region changing in size and shape. This study highlights the dynamic nature of the skull and sheds light on the influence the eyes (a soft tissue) have on the surrounding skull (a hard tissue) a topic which has been overlooked in the literature.

Taste buds are spindle-shaped collections of taste receptor cells located in the surface epithelium of the oral cavity. Taste receptor cells are specialized sensory epithelial cells that are responsible for the transmission of taste information to the taste nerves. Immunocytochemical evidence of the neuropeptide cholecystokinin in various taste cells of the rat has been presented by our lab (Herness 1991). These results have prompted our investigation of the messenger RNA encoding this peptide in rat taste cells. CCK may play an important role in taste signal transmission or modulation.Three areas of the oral cavity were investigated for the presence of CCK mRNA. Two of these areas contain collections of taste buds in well-defined structures called papillae. Circumvallate papillae, located on the posterior surface of the tongue, and foliate papillae, located on the lateral surfaces of the tongue, were sectioned and probed for CCK mRNA using non-radiographic in situ hybridization. The third area investigated was the nasoincisor duct, located on the roof of the oral cavity. This duct contains isolated taste buds within the surface epithelium near the opening to the oral cavity.The results of this study confirm the presence of CCK mRNA in all three areas studied. Taste buds located in the circumvallate papillae, foliate papillae and in the nasoincisor duct all contain taste cells that express CCK mRNA. These results are verified by the absence of labeled cells in negative control experiments. The negative controls consists of the omission of probe, anti-DIG antibody, and the application of a sense probe. The immunocytochemical results show only a subset of taste cells labeled for the CCK peptide while the in situ results depict all cells in the bud labeled for CCK mRNA. The in situ results very closely parallel the immunocytochemical results previously obtained by our lab, although with in situ hybridization epithelial staining is more prominent. The surface epithelium contains the messenger RNA encoding CCK likely because taste receptor cells are derived from the lingual epithelium.Several roles for CCK can be considered in taste physiology. Taste reception and taste signal transduction is not fully understood. Also the localization and pharmacology of CCK receptors in taste systems awaits investigation. These two areas must be studied further to understand the function of CCK in taste cells. / Department of Biology

Thesis (M.Sc.) (Honours) -- University of Western Sydney, Hawkesbury, 2001. / A thesis submitted in fulfilment of the requirements for the degree of Masters of Science (Honours) in the Centre for Advance [sic.] Food Research, University of Western Sydney, Hawkesbury Campus, July 2001. Bibliography : leaves 98-110.

D.Sc. / Please refer to full text to view abstract

As alterações do paladar durante o transplante de células tronco hematopoiéticas (TCTH) são frequentemente descritas em períodos após a finalização do transplante, porém pouco se conhece sobre quais sabores e que tipo de alterações de percepção são vivenciadas pelos pacientes durante o transplante. O objetivo deste trabalho foi caracterizar as alterações do paladar e de despapilação presentes no período de neutropenia do TCTH, bem como verificar se há associação entre essas alterações e variáveis clínicas relacionadas ao transplante e à toxicidade na mucosa oral. Também se avaliou o impacto das alterações do paladar e da mucosa oral na qualidade de vida dos pacientes. Foram selecionados 52 pacientes de TCTH autólogo e alogênico, que realizaram testes de acuidade do paladar antes do condicionamento e durante a neutropenia. Os pacientes foram ainda submetidos a oroscopia para avaliação de mucosite oral e despapilação no dorso da língua. Foi também realizado inquérito quanto a xerostomia e a alterações no paladar. Foi realizado teste de acuidade na percepção dos sabores doce, amargo, azedo e salgado, ofertados em soluções contendo concentrações baixas e altas de substâncias estimuladoras desses sabores. A qualidade de vida foi avaliada pelo questionário EORTC QLQ-C30 e QLQ-H&N35. Detectou-se que os 46,1% dos pacientes exibiram alterações do paladar antes do condicionamento do TCTH, mas que essa frequência aumentou para 90,5% durante a neutropenia (teste do c2, p=0.042). O tipo de alteração mais comum foi a hipogeusia dos sabores de concentração mais forte, principalmente do amargo. Alta frequência de pacientes (72,0%) foi detectada exibindo despapilação no período de neutropenia, porém essa despapilação não foi associada às alterações de percepção de cada tipo de sabor. Não houve associação entre alterações do paladar e tipo de transplante, tipo de condicionamento e variáveis relacionadas à toxicidade na cavidade oral e no trato gastrointestinal. Houve associação significativa entre despapilação e duração da mucosite oral >=8 dias (OR= 5,62, IC95% = 0,98-60,30, p=0.039). As alterações salivares e do paladar reduziram significativamente na qualidade de vida durante a neutropenia em comparação ao período que antecedeu o condicionamento. Concluiu-se que as alterações do paladar já estão presentes antes do TCTH, mas há aumento da frequência dessas alterações, principalmente de hipogeusia. A despapilação na língua ocorreu após o condicionamento, e foi associada a maior tempo de duração da mucosite oral. O impacto das alterações salivares e do paladar na qualidade de vida do paciente durante a neutropenia é alto e devem ser minimizados mediante a adoção de estratégias mais abrangentes, que incluam manutenção da integridade da mucosa oral. / Taste changes during hematopoietic cell transplantation (HCT) are often described after the end of transplantation, however little is known about which flavors and what type of perception changes are experienced by patients during transplantation. The aim of this study was to characterize the taste alterations and taste buds atrophy present in the period of neutropenia of HCT, as well as to verify if there is association between these alterations and clinical variables related to transplant and oral mucosal toxicity. The impact of taste and oral mucosal changes on patients\' quality of life was also evaluated. We selected 52 patients undergoing autologous and allogenic HCT, who underwent taste acuity tests prior to conditioning and during neutropenia. Patients were also submitted to oroscopy for evaluation of oral mucositis and taste buds atrophy. An investigation was also conducted on xerostomia and taste changes. It was carried out an acuity test in the perception of sweet, bitter, sour and salty flavors, offered in solutions containing low and high concentrations of substances stimulating these flavors. Quality of life was assessed by the EORTC questionnaire QLQ-C30 and QLQ-H & N35. It was found that 46.1% of the patients exhibited taste alterations before the conditioning of the HCT, but that this frequency increased to 90.5% during neutropenia (c2 test, p = 0.042). The most common alteration was the hypogeusia of the strongest concentrations, especially bitter. High frequency of patients (72.0%) were detected with taste buds atrophy in the period of neutropenia, but this taste buds atrophy was not associated with alterations in the perception of each type of taste. There was no association between changes in taste and type of transplant, type of conditioning, and variables related to toxicity in the oral cavity and in the gastrointestinal tract. There was a significant association between taste buds atrophy and oral mucositis duration >=8 days (OR = 5.62, 95% CI = 0.98-60.30, p = 0.039). Salivary and taste changes significantly reduced quality of life during neutropenia compared to the pre-condition period. It was concluded that taste alterations are already present before HCT, but there is an increase in the frequency of these alterations, mainly hypogeusia. The tongue taste buds atrophy occurred after conditioning, and was associated with a longer duration of oral mucositis. The impact of salivary and taste changes on patient quality of life during neutropenia is high and should be minimized through the adoption of more comprehensive strategies that include maintenance of oral mucosal integrity.

The aim of this study was to quantify the density of taste pores on the anterior region of the tongue, in adult males and 8 to 9 year old boys. Earlier studies had shown that, although 8 to 9 year olds were poorer than adults at sensing the tastant sucrose using a whole mouth procedure, localised regions of the tongue in male children were more sensitive than equivalent regions in adults. This study aims to detemine whether the age differences in sensitivity is related to a difference in taste pore density. Two areas of the tongue, for which children had previously been shown to have higher sensitivity than adults, were examined using a videomicrosocpy technique and the number and diameter of taste pores were measured. Children were found to have a greater density of taste pores, however the number of taste pores per papilla were similar in children and adults. It was found to be likely that the greater sensitivity of localised areas on the children's tongue is due to a greater taste pore density. The reduced sensitivity reported using whole mouth stimulation may be due to a reduced capacity to assimilate taste input from the whole mouth or due to different relative contributions to whole-mouth taste from the various receptive fields in the mouth. / Master of Science (Hons)

No description available.

Chemoreception plays an important role in predator-prey interactions and feeding dynamics. While the chemoreception of attractant or pleasant tasting compounds has been well studied, aversive chemoreceptive signaling has been difficult to investigate behaviorally in an ecological context because these interactions are species- and context- specific and deterrent compounds vary among prey. Using the coral reef system, this thesis explores on a molecular level the deterrent mechanism underlying detection by fish predators of an aversive compound, in order to gain a greater understanding of predator-prey interactions in this community. Like other organisms that are sessile or slow-moving, marine sponges have special mechanisms for defense from predation, commonly containing aversive-tasting compounds that defend these organisms from predation. To this end, we sought to identify and characterize a fish chemoreceptor that detects one or more of these compounds. We isolated a single cDNA clone encoding RAMP-like triterpene glycoside receptor (RL-TGR), a novel co-receptor involved in the signaling of triterpene glycosides. This co-receptor appears to be structurally and functionally related to receptor activity-modifying proteins (RAMPs), a family of co-receptors that physically associate with and modify the activity of G protein-coupled receptors (GPCRs). Expression in Xenopus oocytes showed that it responds to triterpene glycosides in a receptor-mediated manner and requires co-expression of a GPCR to enable signaling in oocytes; both of these receptors may be components of a larger signaling complex. A 40 bp portion of the gene is conserved across multiple fish species, but is not found in any other organism with a sequenced genome, suggesting that the expression of this receptor is limited to fish species. RL-TGR is the first identified gene encoding a co-receptor that responds to a chemical defense. This finding may lead the way for the identification of many other receptors that mediate chemical defense signaling in both marine and terrestrial environments, as this protein has the potential to represent the first of an entire family of co-receptors that respond to aversive compounds.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-04-20T15:07:15Z No. of bitstreams: 1 pilarcozendeysilva.pdf: 4550098 bytes, checksum: db6b2e284bcd0084843d5f3089502818 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T03:03:46Z (GMT) No. of bitstreams: 1 pilarcozendeysilva.pdf: 4550098 bytes, checksum: db6b2e284bcd0084843d5f3089502818 (MD5) / Made available in DSpace on 2016-04-24T03:03:46Z (GMT). No. of bitstreams: 1 pilarcozendeysilva.pdf: 4550098 bytes, checksum: db6b2e284bcd0084843d5f3089502818 (MD5) Previous issue date: 2015-02-12 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / Os répteis Squamata possuem um sistema sensorial sofisticado, adaptado ao ambiente em que vivem e as atividades desempenhadas em seu forrageio. A língua de lagartos é estrutura componente do sistema sensorial fundamental para o forrageio. Desta forma, o presente estudo buscou investigar a estrutura morfo-histológica da língua de cinco espécies de lagartos brasileiros (Ameiva ameiva, Hemidactylus mabouia, Aspronema dorsivittatum, Ophiodes striatus e Tropidurus torquatus) e sua relação com os tipos de forrageio. Foram analisados o formato e comprimento de língua e confeccionadas lâminas histológicas coradas com HE e PAS, de exemplares das cinco espécies. As espécies estudadas apresentaram revestimento de epitélio pavimentoso estratificado queratinizado, com variações topográficas na espessura da camada córnea. Ameiva ameiva apresentou a língua mais especializada e restrita ao forrageio ativo, enquanto Hemidactylus mabouia e Tropidurus torquatus apresentaram língua com estrutura menos favorável ao “tongue-flicking” e, portanto, mais próximo de forrageio de emboscada. As espécies Ophiodes striatus e Aspronema dorsivittatum apresentaram resultados característicos tanto de forrageio ativo quanto de emboscada, demonstrando uma provável plasticidade entre estes extremos. Esta flutuação entre tipos de forrageio já foi observada dentro do antigo gênero Mabuya a partir de estudos prévios que indicam que fatores como disponibilidade de alimento e alterações de habitat são capazes de alterar a dinâmica de forrageio de algumas espécies. No presente estudo foi possível relacionar aspectos como tipos de papilas, formato de língua, arranjo muscular, camada de queratina, presença de botões gustativos, entre outros, com a provável dinâmica de forrageio das cinco espécies estudadas. O arranjo muscular encontrado nos forrageadores ativos foi considerado mais compacto e direcionado ao “tongue-flicking”, enquanto o dos forrageadores de emboscada o arranjo muscular se mostra menos restrito. A análise das características externas e microscópicas da língua trouxeram grandes contribuições para o entendimento de como cada espécie, por exemplo, otimiza a sua percepção do ambiente, como percebe o tempo e seu gasto energético. Além disso, contribui com maiores informações a cerca da morfologia e ecologia de espécies ocorrentes no Brasil. / The Squamata reptiles have a sophisticated sensory system, frequently adapted to the environment in which they live and the activities performed in their foraging. The tongue lizards is a fundamental structure of the sensory system for foraging. Thus, this study sought investigate the morphological and histological tongue structure of five species of Brazilian lizards (Ameiva ameiva, Hemidactylus maboiua, Aspronema dorsivittatum, Ophiodes striatus e Tropidurus torquatus) and its relationship with ambush and active foraging. For that, were analyzed the shape and elongation and made histological slides of language specimens of the five species and colored by HE and PAS. The tongue of all species showed stratified squamous keratinized epithelium, with the keratin layer varying in thickness and position in the tongue. Ameiva ameiva showed the most specialized tongue and restricted to wile foraging, while H. mabouia and T. torquatus presented tongue with less favorable to “tongue-flicking” and therefore closest to ambush foraging structure. The O. striatus and A. dorsivittatum specie showed characteristics of both foraging types, showing a probable plasticity between the extremes of wile and ambush foraging. This fluctuation between types of foraging has been observed within the old genus Mabuya from previous studies that indicate that factors such as food availability and habitat changes are able to alter the dynamics of some species foraging. In the present study it was possible to relate aspects such as types of papillae, tongue shape, muscular arrangement, keratin layer, among others, with the possible dynamics of foraging the five species. The muscle arrangement found in active foragers was considered more compact and focused for the “tongue-flicking”, while the ambush foragers muscle arrangement shown less restricted. And stand out from other factors such as the presence of taste buds. The analysis of external and microscopic characteristics of the tongue provided great contributions to the understanding of how the lizard optimizes its environment perception, as realize the time and its energy expenditure. Also contributes with more information about the morphology and ecology of species occurring in Brazil.