Tesi sul tema "Taste buds"

Cholecystokinin (CCK) is - a multifunctional peptide hormone that is widely distributedthroughout the body. Initially discovered as a gut hormone, CCK is important in integrating many digestive functions. In the nervous system cholecystokinin functions as a neurotransmitter or neuromodulator. It is also considered by many to be a naturally occurring satiety factor, important for the termination of a meal. Recently, our lab has identified the presence of CCK-like immunoreactivity in taste receptor cells of Sprague-Dawley rats. Preliminary in situ hybridization experiments appeared to demonstrate that the mRNA for cholecystokinin may also be expressed in the lingual epithelium and the taste cells of the circumvallate and foliate papillae of the rat tongue. To provide confirrnatory evidence for the presence of CCK in taste epithelium and to investigate its role in taste receptor cells, we further examined the expression of cholecystokinin mRNA in rat lingual epithelium using Northern blot analysis and RT-PCR. Northern analysis proved to be difficult using standard non-radiographic techniques and small oligonucleotide (35 bp) probes. Generating a 535 by radio-labeled probe with random primed labeling, Northern analysis demonstrated positive bands in control tissue (cerebral cortex and duodenum) but failed to demonstrate binding to lingual tissue. Since expression of CCK mRNA in taste cells could be below the level of detection of Northern analysis, the more sensitive technique of RT-PCR was employed. Similar results were obtained with RT-PCR PCR products were observed in cortical and duodenal tissues, but not in gustatory tissue. Therefore immunocytochemical and in situ hybridization results appear to be in conflict with those obtained with Northern and RT-PCR techniques. There remain many caveats in the collective interpretation of these results and further experimentation, particularly with probes designed to hybridize with differing regions of the CCK gene, will be required to more fully understand the putative presence and processing the CCK mRNA in taste receptor cells.
Department of Biology

The West Indian manatee tongue was examined macroscopically, light microscopically, and electron microscopically (scanning and transmission). The tongue was slender, muscular, and firmly fixed in the oral cavity. Only the cranial tip was free and mobile. Numerous filiform papillae were distributed over the dorsal surface of the rostral lingual region. Caudal to the filiform papillae, multiple raised, round papillae were distributed over the majority of the dorsum. Fungiform papillae were restricted to the lateral margins of the tongue. Caudally, the dorsal and lateral regions showed numerous open fossae and pits. Microscopic examination showed the majority of the lingual dorsum to be covered with a thick stratified squamous epithelium. The caudal dorsal and lateral open pits led to well-developed mucous salivary glands. Foliate papillae, located on the caudal region of the tongue, contained taste buds embedded in the epidermis. Glands within the foliate papillae were mostly mucous, though some seromucous glands were evident. Throughout the tongue, striated muscle was abundant below the epidermis. Blood vessels, lymph channels, and nerve fibers were freely distributed throughout the intermuscular stroma. Nerve fibers reacted positively with neuron specific enolase antibody throughout the lingual structure, including nerve bundles, muscle bundles, glands, and taste buds. Electron microscopy revealed cytoplasmic vacuoles juxtaposed to the nucleus in the stratum spinosum of the foliate papillary region.
Master of Science

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.

Taste buds are chemosensory endorgans embedded in the oral epithelium composed of cells that undergo continuous replacement. Mature taste cells live on average 10-14 days and are replaced by new cells when they die. However, the mechanism by which taste cells are produced and integrated into the taste bud as mature taste cells remains unknown. Previous studies approached this issue from either cell cycle gene expression properties or lineage tracing of precursor cells. In our study, we apply a new fate mapping technique that combines these two ideas. This technique, Mosaic Analysis with Double Markers, allows for simultaneous gene knockout and subsequent tracking of single cells. This allows us to study the potency of precursor cells supplying the taste bud while analyzing how gene function regulates the maturation pathway these taste cells take. The following experiments illustrate the initial phase of this investigation.

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.

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)

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 (Ph.D)--Biology, Georgia Institute of Technology, 2009.
Committee Chair: McCarty, Nael A.; Committee Co-Chair: Kubanek, Julia; Committee Member: Derby, Charles; Committee Member: Goodisman, Michael; Committee Member: Pardue, Machelle; Committee Member: Weissburg, Marc. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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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.

Science and medicine have progressed in unfathomable ways over the past century. Paradoxically, as our result of our advancements in medicine we live in a progressively aging society where the majority of people will have multiple morbidities associated with senescence. The World Health Organization estimates that nearly 100% of the population will suffer dental maladies, which left untreated compound with age. We hope to gain new biomedical insight applicable to the advancing field of dental regenerative therapeutics. This dissertation reveals new dental biology through studying the embryology, genetics and evolution of teeth across patterning, morphogenesis and regeneration. We exploit an innovative model, the Lake Malawi cichlid fishes, to study these processes in a natural system. Malawi cichlids have rapidly evolved diverse species-specific dentitions, ranging from hundreds to thousands of teeth that represent a rainbow of shapes and sizes, yet Malawi cichlid species has nearly identical genomes, offering us a powerful genetic system. Furthermore, unlike classic vertebrate models in embryology such as zebrafish, chicken or mice, cichlids have oral teeth and the ability to replace each tooth constantly throughout their lifetimes. In the first study, we break-down the process of whole de-novo tooth replacement in cichlids. We then explore the re-deployment of initiating gene pathways later in the morphogenesis of each replacement tooth (RT). In the second study we investigate the co-patterning of two placode derived oral organs, teeth and taste buds (TBs), and uncover new genes that may modulate their number and size. We subsequently discover a bipotency of progenitor tissue to form both organs and a later plasticity to trans-fate it through coordination of a Wnt-BMP- Hh genetic hierarchy. In the last study, we explore the stem cells that are responsible for the phenomenon of lifelong cichlid tooth replacement. We describe a common epithelium connected to TBs and rich in stem cells, with a newly discovered stem cell niche at the tip of the RT. We uncover the transcriptomes of both organs, and through differential gene expression informed manipulations, coerce dental cells to display TB characteristics. We hypothesize that TB stem cells may be used in dental therapeutics.

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第10885号
農博第1391号
新制||農||888(附属図書館)
学位論文||H16||N3896(農学部図書室)
UT51-2004-G732
京都大学大学院農学研究科応用生命科学専攻
(主査)教授 伏木 亨, 教授 井上 國世, 教授 安達 修二
学位規則第4条第1項該当

The relationship between initial intracellular pH (pHi) and associated cell volume change was investigated by simultaneous measurement of pHi and cell volume with fluorescence imaging in polarized fungiform taste receptor cells (TRCs) loaded with BCECF in vitro. Ammonium pulses caused a brief, reversible alkalinization in pHi and induced cell swelling. Sodium-acetate pulses reversible decreased TRC pHi and induced cell shrinkage. Removal weak acids and return to Control Ringer's solution (CR) causedTRC pHi and volume to overshoot baseline levels before fully recovering. Replacing CR with zero-sodium solution resulted in irreversible acidification of TRC pHi and induced cell swelling. Addition of sodium allowed reversal of TRC pHi and volume and return to baseline levels. Treating TRCs with cytoskeleton inhibitors, phalloidin and cytochalasin, before acidic stimulation did not affect TRC pHi, but did result in an altered TRC volume change. I conclude that a decrease in TRC pHi induces cell shrinkage via the actin cytoskeleton. Cell shrinkage as a result of a change in pHi activates NHE1 to restore TRC pHi and volume.

碩士
國立嘉義大學
視覺藝術研究所
99
The main theme of the thesis is to explore the creative concepts and visual vocabularies of my painting by means of investigating personal experiences of popular food culture. The purposes of this research: 1. through investigation of popular culture theories and Pop Art to construct personal creative concepts about populace food. 2. Transforming the images of populace food culture into personal symbols of my painting practices. 3. Through evaluating the achievements and weakness of current research project to prospect the future developments of my artistic production. The methodology of my research includes: 1.literature reviews; 2. case study method. The thesis includes: First chapter－the motive, purpose, the limitation, and the methodology of this research; Second chapter investigates related cultural theories, aesthetics, art theories, and contemporary arts of my painting practices. Third chapter covers the analysis of significance and visual language of my painting series. Chapter four analyzes the individual artworks. Chapter five is the conclusion of my research project. Keywords：Pop Art, mass culture, gourmet, populace food culture, painting creation

博士
國立臺灣大學
解剖學研究所
85
Most mammalian taste buds are located in fungiform, foliate and circumvallate papillae on dorsal surface of the tongue. Two large, well-defined fields of vallate papillae are situated on each side of the posterior tongue in guineapigs, while in other rodents only a single vallate papilla is present on the midline of the tongue root. Taking the advantage of this special arrangement of guinea pig vallate papillae, we studied the fine structure, immunocytochemistry and nerve distribution of vallate taste buds. The present study includes fiveparts: 1) Fine structure of vallate taste buds, 2) Immunohistochemical studies of neuropeptides and neurotransmitters in vallate papillae, 3) Immunoelectron microscopic studies of PGP9.5- and CGRP- immunoreactive elements in vallate taste buds, 4) Unilateral innervation of vallate papillae and 5) Apoptosis in vallate papillae after neurectomy. Ultrastructural studies revealed four distinct cell types (type I, II, III and basal) in guinea pig vallate taste buds. Type I cells were narrow elongated cells containing an oval nucleus and possessed large, electron- dense granules(about 300nm) apically. Type II cells were characterized by a large and roundnucleus and a conspicuous stack of smooth endoplasmic reticulum in the supra- and infra- nuclear regions. Type III cells made synaptic contacts with nerveterminals and contained dense-cored vesicles (about 90nm) accumulating in the presynaptic areas. Basal cells were situated at the base of buds and considered to be precursors of the other types of cells. Indirect immunohistochemical detection of protein gene product 9.5 (PGP9.5), calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP), galanin and 5-hydroxytryptamine (5HT) showed that numerous PGP9.5- and CGRP-immunoreactive nerve fibers were found to form plexuses in the lingual epithelium both intragemmally and extragemmally. In the subgemmal connective tissue, PGP9.5-, CGRP-and SP-immunoreactive nerve fibers were also observed. Besides, some taste cells were PGP9.5 and 5HT immunoreactive. Neither VIP nor galanin immunoreactivity was detected in nerve fibers and taste cells. The results from immuno-electron microscopy on the location of PGP9.5 and CGRP showed that immunoreactivity for PGP9.5 was localized in all the neural elementsand the cytoplasm of the type III cells. An intensive PGP9.5-immunoreactivenerve fibers formed a subepithelial plexus which issued branches upwards throughthe basal lamina then formed intragemmal and extragemmal networks. CGRP-immunoreactivity was found in nerve terminals making synaptic contacts with type III cells. HRP tracing and unilateral glossopharyngeal neurectomy were performedsimutaneously to determine the innervation pattern by primary afferent nerve fibers and the neurotrophic effect on taste cells in guinea pig vallate taste buds. After the injection of HRP into the proximal ends of the right glossopharyngeal nerve, light microscopy revealed that the HRP- labelled nerve fibers innervated the vallate taste buds of the injected side. Most of the cells in tastebuds were labelled with HRP. At the ultrastructural level, the reaction products were identified in type I, II and III cells, but not basal cells. Our neurectomical results showed that, on the denervated side, the taste buds decreasedsignificantly in number during the first 2 wk, and disappeared completely by week 3; no mature taste buds were present even 24 wk afterneurectomy. Finally,based upon the speculation that gustatory nerve sectioning may enhance apoptosis of taste bud cells with taste buds decreasing in number andultimately disappearing, we further investigated the issue of taste bud cell apoptosis using terminal deoxynucleotidyl transferase mediated nick-endlabelling (TUNEL) method after unilateral glossopharyngeal neurectomy. There results showed that although only very few positively stained nuclei indicating apoptosis were observed innormal taste buds, in the surgically denervated vallate taste buds, the numberof apoptotic cells increased from 6 h, reached at peak on day 1 and gradually decreased from day 3 and day 7 postneurectomy. Electron microscopy revealed that apoptotic cells in both normal and neurectomized taste buds showed characteristic fine structural morphology of apoptosis. From the above observations, we conclude that, in guinea pig vallate tastebuds, 1) type III cells are the bona fide gustatory receptor cells and PGP9.5is a marker of type III cells, 2) CGRP-containing nerve fibers and 5HT-containing taste cells may be primarily involved the neural transmission and its modulation of the taste sensation, respectively, 3) right and left vallate papillae are unilaterally innervated by the glossopharyngeal nerve without cross-innervation, 4) glossopharyngeal neurectomy enhances the apoptosis of taste bud cells and 5) an apporpriate innervation of glossopharyngeal nerve is an essential component in maintaining the normal function of taste buds.

碩士
國立高雄應用科技大學
觀光與餐旅管理系
99
Many people take blog as a stage to show their ideal characters, express their expertise or interests via their personal blogs. Meanwhile, rich and diversified Taiwanese culture has developed a culture of gourmet and also create a group of food lovers. Nowadays, with highly developed internet, many food lovers begin their career in food critic and review via blog. Gourmet blogs have become a popular subjects and hot issue in Taiwan. In this study, we use semi-structured in-depth interview to collect data from eleven food bloggers, in order to explore their history and know-how for running their blogs. The purpose of this study is to investigate how food bloggers live up to their self-images. Based on Goffman's theory of self-presentation, the study discuss how food bloggers identify themselves with the character and how they perform, and also what they intend to gain from the performance. Besides, by analyzing these food blogs, we inquire the issue as how the food bloggers reach their marketing goals and whether working with food industry conflicts with their ideal characters or not. The result shows that the food bloggers use visual stimulating codes to perform the roles that they intend to shape, and this brings about the appeared resonance between their image and their performance. Such resonance motivate the audience to follow the bloggers and then the relationship becomes real through the interaction on the web. The industries thus have to take the blogs seriously, and they in turn will make use of the blog to serve their business interests.

The specific objectives of this thesis were (1) develop a rapid and portable method to quantify fungiform papillae on the anterior tongue of children and adults, (2) determine how fungiform papillae density changes through childhood to adulthood, (3) determine whether a particular region of the tongue is a reliable predictor of the fungiform papillae density of the anterior tongue, (4) validate the earlier work of others in quantification of fungiform papillae in small regions of the anterior tongue, (5) develop a non-invasive method for counting papillae, and (6) determine whether chronic renal failure (CRF) affects fungiform papillae density. The study demonstrated that there were differences in fungiform papillae characteristics in children and adults and that a digital camera provides a convenient tool for achieving these findings. Children aged 11-12 years had similar fungiform papillae densities and predictor areas as adults and it was concluded that fungiform papillae maturity was reached at this age. The results also identified the best predictor of fungiform papillae density for children and adults. Additionally, the methods used by other earlier studies were validated, and the results demonstrated that small tip regions of the anterior tongue were suitable indicators of fungiform papillae density. Importantly, a non-staining method was developed to count papillae and the new method was used in a clinical setting, where it was shown that, patients with CRF had significantly lower fungiform papillae densities than their clinical controls. Overall, the results indicate that a digital camera provides a simple and convenient means for conducting anatomical studies on the anterior tongue of humans both in the laboratory and clinical settings.

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.

碩士
國立臺灣大學
解剖學暨生物細胞學研究所
95
Recently studies on the taste bud are focused on the neurotransmitters and cell communications and seldom the morphology, of the taste bud. Dystonia musculorum (dt) was originally described as a hereditary sensory neurodegeneration syndrome of the mouse (mutant dt/dt). The gene defective in dt encodes a cytoskeletal linker protein, dystonin, that is essential for maintaining neuronal cytoskeletal integrity. The db/db mouse has defective leptin receptors and the defects lead to impairments of leptin regulation of food intake and body weight, and result in the expression of diabetic symptoms such as hyperinsulinemia, hyperglicemia, and extreme obesity. In order to determine the effect of hereditary (in dt/dt mice) and metabolic disturbance (in db/db mice) on the morphology and nerve distribution of the vallate taste bud, a comparative study was performed among the wild type, dt/dt, and db/db mice, to examine the morphology at light and electron microscopic level, and distribution and abundance of the PGP-9.5 immunoreactivity in the taste buds of the vallate papilla. Morphometry and quantitative analysis on the distribution of taste buds and their gustatory nerve fibers are also demonstrated. Compared with wild type mice, the size of vallate papillae is much smaller in dt/dt mice (indicated by the total thickness of frontal sections, 330±19.25μm, vs. 240.3±20.07μm; n=3) and the number of taste buds decreased significantly (94.98±3.1, vs. 58.21±5.12 taste buds/papilla, n=3). However, in db/db mice, the morphology and size of vallate papilla (343±11.43μm, n=3) and the number of its taste buds (98.69±5.06 taste buds/papilla, n=3) are not apparently different from those of the wild type. The results from the PGP9.5 immunohistochemistry showed that the nerve innervation in taste bud cells was significantly reduced in dt/dt mice (25±4.02%, n=3), (indicated by proportion of PGP9.5 immunoreactive cells and fibers of the vallate papilla epithelium containing taste bud), as compared with wild type (47±2.84%, n=3) and db/db (48±8.79%, n=3) mice. Ultrastructural examination reveals four types of taste bud cells, i.e., type I, II, III and baseal cells. All of them express distinctive nuclear morphology, various cytoplasm electron density and characteristic subcellular organelles, in the vallate taste bud from the wild type and db/db mice. However, the cell density and nuclear morphology of the taste cells in dt/dt mice are not so distinct, and it is difficult to differentiate four types of taste bud cells at lower power electron microscopy, however, it is feasible at high power magnification. These findings confirmed our morphological findings at light microscopic level. We conclude that the sensory deficiency in the mutant dt/dt mice affects the morphology and innervations severely of taste buds, however, the metabolic disturbance of the mutant db/db mice does not interfere the structure and innervation of the taste buds in the vallate lingual papilla.

博士
國立臺灣大學
解剖學暨細胞生物學研究所
89
Taste is referring to the sensations arising from stimulation of gustatory receptors located within the oropharyngeal mucosa. Taste information arises from stimulation by chemicals dissolved in saliva, which initiate the depolarization of receptor cells located on the oropharyngeal mucosa. The receptor cells make synaptic contact with the fibers of one of the cranial nerves (CN VII, IX, and X), which concerning with taste perception. Fibers from these nerves project to the medulla into the nucleus of the solitary tract (NST), where the nerve fibers project to connect pons or/and thalamus, and then to taste area in the cerebral cortex. In addition to its obvious role in the perception of sour, sweet, bitter and salty sensations, taste input is important in regulating a number of visceral reflexes involved in ingestive and digestive functions. By means of the important role mention above, taste disturbed can impact health and quality of life. When the anatomical organ of taste --- taste bud or/and nerve become damaged disturb the ability of taste results. Taste disturbance is commonly observed in patients who were affected by illness or by received drug therapies. Nutrient deficiency also has been reported leads to taste disturbance. In order to understand the relationships between taste disorder caused by illness, drug and nutrient deficiency with the morphological changes of taste bud, we studied the development and innervation of vallate papillae and taste buds in mice by using immunohistochemistry, observed the ultrastructure changes and made morphometric analysis of vallate papillae and taste buds in PTU treated mice and gerbils, thyroidectomized gerbils, and zinc-deficient rats. Immunohistochemical studies on the development and innervation of vallate papillae and taste buds in mice, with antibodies against protein gene product 9.5 (PGP 9.5), calcitonin gene-related peptide (CGRP), sbstance P (SP), nitric oxide synthase (NOS)，brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), revealed that the earliest sign of median vallate papilla formation appears at embryonic day 13 (E13) and the newly formed taste buds were recognizable at postnatal day 1 (P1). Thin PGP 9.5-immunoreactive (IR) nerve fibers penetrated the apical epithelium and medial trench wall epithelium of the papilla at E16 and a few of these began to invade the lateral trench wall epithelium at E17. At P1, PGP 9.5-IR cells appeared on the newly formed taste buds. After the present of taste buds, PGP 9.5 IR fibers were found from the underlying subgemmal connective tissue penetrating into the lingual epithelium both intragemmally and extragemmally. The immunoreactivity of CGRP, SP and NOS were observed later than PGP 9.5-IR. The distribution pattern of CGRP- and SP-IR nerve fibers was similar to that of PGP 9.5-IR nerve fibers. SP-IR taste cells were occasionally found in the taste bud. The faintly stained NOS-IR taste cells and the nerve fibers were revealed in the underlying subgemmal connective tissue postnatally. NGF and BDNF immunoreactivity was first seen at the boundary between the columnar cells in the apical epithelium of the developing vallate papilla at E13, then in the medial and lateral trench walls at E15 (BDNF) or E18 (NGF). At P1, BDNF and NGF immunoreactivity was exclusively present in the cells of the newly formed taste buds, and then the immunoreactivity was observed in the most of spindle cell in the taste bud. Morphometry and morphologic changes of their vallate papillae and taste buds in the zinc-deficient rats were analyzed by using light and transmission electron microscopy. Morphometric analysis revealed no significant difference in the papilla size and morphology among the various groups. In both weanling and young adult rats fed the zinc-deficient diet and the pair-fed rats, the number of taste buds per papillae (per animal) and the average profile area of the taste bud were significantly smaller than those of the corresponding controls (p<0.05). Ultrastructural changes were seen only in the taste buds of weanling rats fed with the zinc-deficient diet. Derangement of the architecture of the taste bud and widening of the intercellular space between taste bud cells was seen. The proportion of type I cells in the taste buds of weanling rats fed the zinc-deficient diet decreased from 59% to 39%, and that of the type II cell decreased from 25% to 12%. No obvious changes in the ultrastructure of type III cells were observed. The results of the histology and ultrastructure of vallate taste buds after PTU treatment and thyroidectomy were consistent. The number of taste bud containing degenerating cells was increased and two kinds of degenerating cells, the light-vacuolated cells and the dark-condensed cells were also increased significantly. The vacuoles observed in the light-vacuolated cells were identified as dilated cisternae of the endoplasmic reticulum (ER). The dark-condensed cells were characterized by pyknotic nucleus and dense cytoplasm. Morphometric analysis revealed that the number of type I and type II cells were decreased, and light-vacuolated and dark-condensed cells were increased in the vallate taste buds after PTU treatment and thyroidectomy. The number of light-vacuolated cells and dark-condensed cells increased in the PTU-treatment animal, which peaked at day 11 in the gerbil and at day 14 in the mouse and then decreased slowly afterwards. In the thyroidectomy animals, the number of degenerating cells did not show the peak but instead of keeping constant after the number of these cells increased to the maxim. From the above observations, our main conclusion are as follows: (1) Because vallate papilla was formed prior to its innervation, the initiation of papilla formation does not require any direct influence from the specific gustatory nerve. Neurotrophins in the early developing vallate papillae might act as local tropic factors for the embryonic growth of nerve fibers to induce differentiation of the taste buds. (2) The main effects of zinc-deficiency, in weanling and young adult rats and in adequate diet pair-fed group, were the changes in the number and size of taste buds and in the fine structure of the taste bud cells, especially during the accelerated growth stage after weanling. (3) The results of PTU-treatment suggests that PTU might induce significant morphological alterations in gerbil and mice vallate taste buds. (4) Deficiency of the thyroid hormone causes significant morphological alterations in thyroidectomized gerbil vallate taste buds.

碩士
國立臺灣大學
解剖學研究所
83
The histology and ultrastructure of vallate taste bud in postadrenonectomy Wistar rats were compared to those in normal or sham-operated animals. The effect of salt intake on the taste bud was also investigated. Experimental animals were divided into five groups as following: (1)ADX+So(22): adrenalectomized and provided normal saline as daily drink; (2) ADX +Si(20): adrenal- ectomized, provided tap water as daily drink, and an injection of normal saline intraperitoneally daily (2-3 ml per day); (3) Sham+ So(18): sham operated and provided normal saline as daily drink;(4) Sham+Si: Sham operated and injected normal saline intraperitoneally daily (2-3ml perday); (5) Normal: no operation and provided tap water as daily drink. All animals were sacrificed one, two, or three week after each treatment and the rat vallate papillae was processed for light- and electron- microscopy. We measured the size of the taste bud in the vallete papilla and analyzed the cell number in the taste bud at light microscopic level. Histological observations revealed that taste buds of rat vallete taste buds were localized within the layer of stratified squamous epithelium in the trench around the papilla. The apical end of the taste bud is communicated with the oral cavity through the trench via taste pore, while the base of the taste bud attached to the underlying connective tissue by basement membrane. Taste cells can be divided into dark cells and light cells and into type I, II, III and basal cells at light and electron microscopic level respectively. No obvious difference in histology or ultra-structure of vallte taste buds was observed in all the animals, except that mitotic basal cells were more often seen(7-8%) in adrenalectomized animals than in normal animals(2-3%).

碩士
國立雲林科技大學
文化資產維護系碩士班
92
This paper take the local cultural taste bud as the topic to discuss the relation between the form of whale-dolphin consciousness in Taiwan with the change of eating dolphin in coastland since whale-dolphin was listed as conservation object for 14 years.The problems relevant to the consciousness include what kinds of seafood are eaten: Dolphin or “hai di”? After whale and dolphin have been conserved; nevertheless, the bad diet still exists and the youths reject such disgusting diet, why? According to the above-mentioned, I attempted to come up with a notion of “cultural taste bud" to explain this phenomenon. In addition, the phenomenon of the circulation of the whale-dolphin meat in the black market has been regarded as the supply-demand matter by the market. In view of this special circulation pipeline, this research further analyzes the viewpoint of the supplies – demand from the angle of low sound resistance. Some other sounds which be neglected will appear. With the recovering of comments, the more reasonable explanation will be discussed why eating the sea pork has been recognized as cruel and uncivilized behaviors. In general, when it comes to the issue about whale-dolphin, we usually start on the conservation viewpoint to make statement that the exotic diet always been thought little of. To concentrate on the point “hai-dia” meat, I can conjecture that such serious situation factually stem from” gaze-consciousness of whale-dolphin”, those who made a set of knowledge system. On the other hands, whenever thought over the more specific interpretations and annotation about these issues, we still failed to answer, including the group of conservationist. If the dolphin becomes the livestock, is it uncivilized and cruel to eat dolphin meat? Eventually, with the view of these viewpoints “the Cultural taste bud”, “the Prohibition in a field survey”, and “the Formation that whale-dolphin savors formulated around the world”, I come up with another vision and angle regarding local culture “preservation” (care) of cultural property.

博士
國立臺灣大學
解剖學暨細胞生物學研究所
103
Arecoline, a major alkaloid in areca nuts, is involved in the pathogenesis of inflammatory oral diseases, cancers and in the developmentally toxic effect of lowering weight and retarding growth of the embryo. Experiment I：Mammalian taste buds are the basic structural unit for detecting taste stimuli in the oral cavity, however, the effects of arecoline on the taste bud are poorly understood. We injected arecoline intraperitoneally into C57BL/6 mice twice daily for 1 - 4 weeks and aimed to revealthe taste bud morphology, life span and gustatory functional activity by immunohistochemistry (IHC) and electron microscopy. At end of arecoline treatment, the animals were sacrificed through perfusion, and the vallate papillae were excised and processed for electron microscopy and immunohistochemistry (IHC) analysis of taste receptor proteins (T1R2, T1R3, T1R1 and T2R) and taste associated proteins (α-gustducin, PLCβ2 and SNAP25). Expression levels of c-fos were detected in the solitary nucleus and gustatory cortex. Body weight, food intake and water consumption were recorded during the treatment period every other day. After arecoline treatment, a two-bottle preference test between water and 1 % sucrose was performed for 4 weeks. For study of taste bud cells life-span, mice were also injected with BrdU (50 mg/kg i.p.) at end of arecoline treatment and then perfused at day 1 to day 14 following BrdU administration. The results demonstrated that (1) arecoline treatment did not change the number and size of the taste buds, and the number of taste bud cells was not affected, (2) electron microscopy revealed the swollen mitochondria, dilated endoplasmic reticulum cisternae, and numerous irregular autophagosomes accumulated in type II cells, (3) IHC demonstrated a decrease in the number of taste receptor T1R2- and T1R3-expressing cells, (4) the level of c-fos expression was decreased in the solitary nucleus and gustatory cortex, (5) the body weight and food intake amount were markedly reduced, (6) the sweet preference behaviour was-reduced, (7) the number of BrdU-labeled taste bud cells was significant reduced at 1, 3, 7 and 14 days, and (8) PCR array experiments showed that the expression of cyclin B2 and E2F1, was markedly downregulated, but the expression of p53 and bax was markedly upregulated by arecoline in the circumvallate. We conclude that the long-term arecoline injection alters the morphology of type II taste bud cells, retards the growth of mice from puberty to adulthood, affects gustatory discrimination competencies, also inhibits taste progenitor cells proliferation and shorten life span of renew taste bud cells. Experiment II：The effects of arecoline on birth defects have been explored in many species, including chicken, mice, and zebrafish. The effects of arecoline on embryos after long-term exposure are well established, however, the effects of short-term arecoline exposure to embryos are not fully understood. Using zebrafish as an animal model, we studied the effects of short-term exposure of arecoline on zebrafish embryos to mimic the areca nut-chewing woman during early pregnancy. Arecoline, at concentrations from 0.001 to 0.04%, was administered to zebrafish embryos from 4 to 24 hpf (hours post fertilization). The morphological changes, hatching and survival rates, body length, and somitic skeletal muscle fiber structure were investigated by immunohistochemistry (IHC), confocal microscopy, and conventional electron microscopy. With exposure of zebrafish embryos to the increasing concentrations of arecoline, we observed a significant decline in the hatching and survival rates, general growth retardation, lower locomotor activity and impairment of swimming ability. Immuno-fluorescence staining demonstrated a loose arrangement of myosin heavy chains, and ultrastructural observations revealed an altered arrangement of somitic myofibril and swelling of the mitochondria. In addition, the results from flow-cytometry, JC-1 staining to assay mitochondria activity, and RT-PCR analysis of mitochondrial functional gene expression, revealed mitochondrial dysfunctions after exposure to arecoline. We confirmed that short-term arecoline exposure resulted in retarded embryonic development and decreased locomotor activity due to defective somitic skeletal muscle development and mitochondrial dysfunction.