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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Biologia floral e reprodutiva e anatomia do labelo de Cyrtopodium polyphyllum Vell. (Orchidaceae, cyrtopodiinae) / Floral and reproductive biology and lip anatomy of Cyrtopodium polyphyllum Vell. (Orchidaceae, cyrtopodiinae)

Mickeliunas, Ludmila 13 February 2007 (has links)
Orientador: Marlies Sazima / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T02:57:58Z (GMT). No. of bitstreams: 1 Mickeliunas_Ludmila_M.pdf: 925385 bytes, checksum: 671e200f723bbbe9d070e825415371fe (MD5) Previous issue date: 2007 / Resumo: O gênero Cyrtopodium Schltr. apresenta cerca de 42 espécies, sendo que 28 delas ocorrem no Brasil. Entre essas espécies Cyrtopodium polyphyllum Vell. (Sinônimo: Cyrtopodium paranaense Schltr.) ocorre, principalmente, na região litorânea do sul e sudeste brasileiros. As duas populações estudadas ocorrem na planície litorânea de Picinguaba e Praia da Fortaleza, Ubatuba-SP. Em ambas as regiões foram estudadas a fenologia, a morfologia floral, a anatomia do labelo, bem como observados os visitantes florais e identificados os mecanismos de polinização de C. polyphyllum. Também foram feitos experimentos para verificar o sistema reprodutivo da espécie. A quantidade de sementes potencialmente viáveis obtidas em cada tratamento, bem como a taxa de frutificação em ambiente natural foram determinadas para avaliar o sucesso reprodutivo. Os resultados dos estudos anatômicos foram comparados com os de outra espécie de Cyrtopodiinae, Grobya amherstiae Lindl. Cyrtopodium polyphyllum não oferece recursos aos seus polinizadores, que são atraídos às flores por engano. Cyrtopodium polyphyllum ocorre simpatricamente e, aparentemente, mimetiza flores de outras espécies que oferecem recursos, como Crotalaria incana (Fabaceae) e Stigmaphyllon sp. (Malpiguiaceae). Além da polinização por fator biótico, algumas flores de C. polyphyllum são autopolinizadas por gotas de chuva, um mecanismo que até então não havia sido descrito para Cyrtopodiinae. Cyrtopodium polyphyllum é autocompatível, mas dependente de polinizadores para a transferência de pólen. O grau de autocompatibilidade varia bastante entre as populações estudadas. Os frutos formados através das autopolinizações manuais, das polinizações cruzadas, assim como os desenvolvidos em condições naturais, apresentam alta taxa de sementes potencialmente viáveis e algumas exibem poliembrionia. Um estudo anatômico das glândulas florais presentes no labelo de Cyrtopodium polyphyllum e Grobya amherstiae foi efetuado com o propósito de relacionar a função desempenhada por estas estruturas com o processo de polinização. Ambas as espécies apresentam osmóforos, estruturas responsáveis pela produção dos odores característicos de cada espécie. Cyrtopodium polyphyllum possui dois tipos de osmóforos: um composto por papilas unicelulares, distribuídas pela superfície adaxial do labelo, e outro composto por emergências pluricelulares, presentes na região do calo do labelo. Em G. amherstiae os osmóforos são compostos por uma única camada de células epidérmicas, e ocorrem em toda a superfície abaxial do labelo. Grobya amherstiae apresenta, ainda, elaióforos, sendo um no ápice do labelo e outro na base da coluna. O elaióforo do ápice do labelo é de estrutura mista, composto por tricomas unicelulares glandulares e epiderme em paliçada, enquanto o da base da coluna é tricomáceo, apresentando apenas tricomas glandulares. Além de osmóforos e elaióforos, G. amherstiae apresenta também um guia de óleo na superfície adaxial do labelo formado por células papilosas / Abstract: The genus Cyrtopodium comprises about 42 species, with 28 occurring in Brazil. Among these species, Cyrtopodium polyphyllum (Synonym: Cyrtopodium paranaense Schltr.) occurs mainly on sandy soils in ¿restinga¿ vegetation along the coast of south and southern of Brazil. Large populations are found in the Natural Reserve of Picinguaba and at Praia da Fortaleza, municipality of Ubatuba, State of São Paulo, regions where this specie was studied. In both study sites were studied the phenology, floral morphology, lip anatomy, as well as recorded the floral visitors and identified the pollination mechanisms of C. polyphyllum. Also were performed treatments to verify the reproductive system of this specie. The quantity of potentially viable seeds obtained in each treatment, as well as the fruit set in natural habitat was recorded in order to evaluate the reproductive success. The results of the anatomic studies were compared with other Cyrtopodiinae specie, Grobya amherstiae Lindl. Cyrtopodium polyphyllum offers none reward to their pollinators, which are attracted to flowers by deceit. Cyrtopodium polyphyllum occur sympatrically and apparently mimicry flowers of other reward producing species, as Crotalaria incana (Fabaceae) and Stigmaphyllon sp. (Malpiguiaceae). Besides of the pollination by a biotic factor, some flowers of C. polyphyllum are pollinated by raindrops, a pollination mechanism not described to Cyrtopodiinae yet. Cyrtopodium polyphyllum is selfcompatible but pollinator-dependent. The tax of self-incompatibility is different between the two studied populations. The fruits formed from manual self-pollinations, crosspollinations, as well as developed under natural conditions, show an elevated tax of potentially viable seeds and sometimes present poliembriony. An anatomical study of the floral glands gifts in lip of Cyrtopodium polyphyllum and Grobya amherstiae were performed with the intention to relate the function played for these structures with the pollination process. Both species presents osmophores, structures responsible by the production odors, which are characteristic of each species. Cyrtopodium polyphyllum presents two types of elaiophores: one is composed by unicellular papillae, distributed along adaxial surface of the lip, and other composed by multicellular papillae arranged on the lip callous. In G. amherstiae the osmophores are composed by a singular layer of epidermic cells, and occurs along of all abaxial surface of the labellum. Grobya amherstiae also presents an elaiophore on the lip apices and on column basis. The elaiophore of the lip apices is a mixed structure, composed by unicellular glandular trichomes and a paliçade epidermis, although the elaiophore of the column basis is trichomatic, presenting only glandular trichomes. Besides of osmophores and elaiophores, G. amherstiae also presents an oil guide on adaxial surface of the labellum made by papillose cells / Mestrado / Mestre em Biologia Vegetal
32

The Effects of a High Caloric Diet and CTRP3 Over-expression on the Myometrium of the Mouse Uterus

Gilmer, Cori, Forsman, Allan, PhD 07 April 2022 (has links)
One of the major healthcare issues found almost worldwide, especially in the United States, is the obesity epidemic. Obesity is known to have deleterious effects on many body/organ systems. C1q TNF-related protein-3 (CTRP3) is effective at preventing high-fat diet-induced fatty liver. With these two factors taken into consideration, this study explores the possible effects of a high caloric diet on the muscle wall of the uterus, i.e., the myometrium, and how over-expression of CTRP3 may modify those effects. We hypothesize that consumption of excessive amounts of fat and sugar will have detrimental effects on the dual layers of the mouse myometrium. For this study, 17 mice were divided into 4 treatment groups: wild type/low fat diet, wild type/high fat diet, CTRP3-overexpressing/low fat diet, and CTRP3-overexpressing/high fat diet. The mice were placed on their respective diets at 7 weeks of age with a feeding duration of 12 weeks. At the conclusion of the feeding protocol, the female reproductive tissues were harvested and fixed in 4% paraformaldehyde and subsequently paraffin embedded. The uterine horns of each mouse were painstakingly paraffin embedded in a vertical position so that cross sections of the uterus could be obtained and measured. These 4µ sections were stained using standard H&E staining techniques and visualized under light microscopy. A randomization grid was utilized to determine measurement locations on the tissue. For each animal, 15 measurements were made of the outer longitudinal layer of the uterine horn, as well as 15 measurements of the inner circular layer, and 15 measurements of the thickness of the two layers combined. Two-way ANOVA was used to determine if any changes seen were statistically significant. At the time of the writing of this abstract, no appreciable differences have been found between the treatment groups, although there will be more data and final statistics completed before the presentation of our findings.
33

Investigating Molecular Biomarkers During Gestational Diabetes Mellitus

Dias, Stephanie Charmaine January 2019 (has links)
Introduction: Gestational diabetes mellitus (GDM) is a significant public health concern, due to its association with short- and long-term complications in both mothers and offspring. DNA methylation and single nucleotide polymorphisms (SNPs) offer potential to serve as molecular biomarkers, which may lead to improved detection of GDM with positive effects on health outcomes. Aim: The aim of this study was to investigate whether DNA methylation and SNPs are associated with GDM and may offer potential as molecular biomarkers for GDM in South Africa (SA). Methods: This study followed a two-pronged approach. Firstly, literature searches were conducted to collate and synthesise all published articles reporting on the prevalence of GDM in SA, the screening and diagnostic strategies used, and the current status of DNA methylation and SNPs as biomarkers for GDM. Secondly, we conducted experiments to investigate global (n=201), genome-wide (n=24) and gene-specific DNA methylation (n=286) of the adiponectin gene (ADIPOQ) in whole blood of women with and without GDM, using an Enzyme-Linked Immunosorbent Assay, a methylationEPIC BeadChip Array and pyrosequencing, respectively. In addition, genotype and allele frequencies of ADIPOQ rs266729 and rs17300539, and methylenetetrahydrofolate reductase (MTHFR) rs1801133 were determined, using quantitative real-time PCR (n=449) and DNA sequencing for validation. Results: The literature search showed that the prevalence of GDM in SA has increased over the years. Furthermore, it showed that the lack of uniformity in screening and diagnosis between and within countries hamper the accurate detection of GDM. Lastly, the literature search identified several studies that support the use of DNA methylation and SNPs as potential biomarkers for GDM. Experimentally, we showed no differences in global DNA methylation between GDM and non-GDM groups. Interestingly, global DNA methylation levels were 18% (p=0.012) higher in obese compared to non-obese pregnant women. Genome-wide methylation analysis identified 1046 differentially methylated CpG sites (associated with 939 genes) (Cut-off threshold: M>0.06 and p<0.01). Among the top five CpG sites identified, one CpG mapped to the calmodulin-binding transcription activator 1 (CAMTA1) gene, which has been shown to regulate insulin production and secretion. Two CpG sites (-3410: p=0.048 and -3400: p=0.004) in the ADIPOQ promoter were hypomethylated during GDM in HIV negative, but not in HIV positive women. Lastly, no association between the ADIPOQ and MTHFR polymorphisms and GDM was observed in our population. Conclusion: To our knowledge, this is the first study to investigate the association between DNA methylation or ADIPOQ (rs266729 and rs17300539) and MTHFR (rs1801133) polymorphisms and GDM in SA. Findings suggest that gene-specific, but not global methylation nor SNPs rs266729, rs17300539 and rs1801133, may offer potential as molecular biomarkers of GDM in this population. Future longitudinal studies in larger samples that include both HIV negative and positive pregnant women are warranted to explore the candidacy of DNA methylation as molecular biomarkers for GDM. / Thesis (PhD)--University of Pretoria, 2019. / National Research Foundation (NRF) of South Africa, Thuthuka Grant (unique grant no. 99391). / South African Medical Research Council (SAMRC) / Obstetrics and Gynaecology / PhD / Unrestricted
34

Distribution and Life History of Chrosomus sp. cf. saylori in the Upper Clinch River Watershed, Virginia

White, Shannon Lynn 21 December 2012 (has links)
In 1999, a new species of minnow, Chrosomus sp. cf. saylori (Clinch dace), was discovered in the Tennessee drainage of Virginia. Chrosomus sp. cf. saylori are listed as a Federal Species of Concern and on Virginia\'s Wildlife Action Plan as Tier II- Very High Conservation Need because of potential threats from habitat degradation, high population fragmentation, and a largely unknown distribution. Consequently, a management plan for C. sp. cf. saylori is of utmost importance, but more information regarding its distribution and life history is required before such a plan can be implemented. In 2011 and 2012 I sampled 60 headwater streams in the upper Clinch River watershed, Virginia.  From this and historical data, I conclude that C. sp. cf. saylori are restricted to eight small tributaries to the Clinch River.  Multivariate analysis of habitat correlates indicated that C. sp. cf. saylori populations are found in small, high elevation streams with gravel substrate and forested watersheds.  Three species distribution models were unable to predict C. sp. cf. saylori distribution.  Morphological traits were significantly different between C. sp. cf. saylori and other Chrosomus, thereby providing an initial indication of speciation and differing niche roles. I observed a nest association with Campostoma anomalum.  Gonad weight was lower for C. sp. cf. saylori than closely-related congeners. Together, this information indicates that C. sp. cf. saylori are narrowly distributed and populations are small, fragmented, and of questionable viability.  In the future, long-term monitoring efforts and genetics analyses should be completed and additional protection measures pursued. / Master of Science
35

Mating System Inferences In Representatives From Two Clam Shrimp Families (Limnadiidae and Cyzicidae) Using Histological and Cellular Observations

Brantner, Justin 13 May 2011 (has links)
No description available.
36

The Effects of Simulated Spaceflight Conditions on the Myometrium of the Mouse Uterus

Elgazzar, Ahmed, Forsman, Allan D, Mao, Xiao W, Pecaut, Michael J, Nishiyama, Nina C, Campbell-Beachler, Mary 12 April 2019 (has links)
As scientific discovery and human presence push further into space, it is necessary to investigate the effects of spaceflight on physiological systems. Research into the effects of the space flight environment on the human body is still in its relative infancy. Although initial studies have indicated harmful effects of spaceflight environments on certain body systems, this phenomenon still needs illumination with regards to the female reproductive system. Better understanding of these consequences can change the way society views space travel and colonization of other planets. The spaceflight environment consists of at least two major factors that could confer negative effects on physiology, namely radiation and microgravity. In this experiment, uterine smooth muscle, or the myometrium, was analyzed in 6-month old female C57BL/6 mice that were exposed to 21 days of low dose/low dose rate whole-body radiation with γ-radiation using 57Co plates (0.04 Gy at 0.01 cGy/h) and/or simulated microgravity (via hind limb unloading). Tissue samples were harvested 4 months after the 21-day simulated spaceflight period. Following embedding, sectioning, and hematoxylin and eosin staining (H&E), the tissues were examined, and the average thicknesses of the myometrial layers were measured. Three types of measurements were made 1 – outer longitudinal layer, 2 – inner circular layer, and 3 –total muscle layer thickness (outer and inner combined). Two-way ANOVA statistical tests were used to compare the thicknesses of the myometrial muscle layers between the various treatment groups. A statistical difference was found between the thicknesses in the outer longitudinal layer of smooth muscle between the control animals and the unloaded animals (P: 0.051).
37

Ecological Factors, Mixed Breeding System and Population Genetic Structure in a Subtropical and a Temperate Violet Species

Cortés-Palomec, Aurea C. 07 October 2005 (has links)
No description available.
38

Characterizing early growth and reproduction of Blueline Tilefish (<i>Caulolatilus microps</i>) to inform stock assessments

Low, Jonathan 21 May 2024 (has links)
Blueline Tilefish is a deepwater species that is found along the United States Atlantic coast and in the Gulf of Mexico. Fisheries for the species have developed in the past five decades, and large increases in landings from the mid-2000s to 2010s have raised management interest. During the most recent stock assessment, age reading difficulties found in the past persisted, and preferred age-structured models were not used. Additionally, maturity was estimated from a meta-analysis of other species with similar life histories. Research recommendations from independent peer reviewers thus included improving age determination as well as collection of small fish. We collaborated with charter fishermen to target small (< 400 mm total length [TL]) blueline tilefish. We also collaborated with scientists at South Carolina Department of Natural Resources (SCNDR) on histological reproductive phase coding and ageing of Blueline Tilefish otoliths. We optimized the information incorporated into sex ratio, reproduction, and growth analyses by merging datasets with SCDNR and Old Dominion University (ODU), and assessed first maturity to the increase immature sample size. Overall sex ratios exhibited a female bias, displaying statistically significant deviations from the expected 1:1 ratio in both the Southeast United States Atlantic (SEUS) and United States Mid-Atlantic (USMA) regions. All immature individuals collected measured below 400 mm. Our findings aligned with previously documented spawning seasons, which extend from April to October in the SEUS and from May to November in the USMA, and may extend to November in the SEUS. The spawning peak identified for the SEUS concurred with previous studies, and suggested October as a spawning peak in the USMA—later than previously described. Sex-specific gonadosomatic index analyses indicated no significant differences between regions. Age determination remained challenging, but the level of agreement in age estimates between the VT consensus and SCDNR readings resembled the highest value from previous studies. Evaluation based on AIC and BIC scores of weight-length relationships indicated potential regional differences and sexual dimorphism within both the SEUS and USMA regions. This sexual dimorphism was further supported by von Bertalanffy growth estimates, revealing L_∞ values of 574.7 and 630.1 mm TL and values of 0.22 and 0.24 for females and males, respectively. Analysis of AIC and BIC indicated sexual dimorphic growth. Length and age at 50% maturity estimates ranged from 283 to 357 mm TL and a few months to 3.7 years, respectively. Length at maturity models also indicated that most fish are mature around 400 to 500 mm, highlighting the importance of targeting smaller individuals to increase the sample size of immature fish. Differences in AIC and BIC scores for length and age at maturity models of three maturity scenarios were low (AIC and BIC < 2). We recommend continued investigation into blueline tilefish age determination, as well as targeted efforts to collect more immature blueline tilefish. Additionally, we propose the use of first maturity and data weighting for maturity estimation of this species. / Master of Science / Blueline tilefish, a deepwater species found in the US Atlantic and Gulf of Mexico, has become an increasing concern for fisheries managers due to rising catches in the mid-2000s to early 2010s. In our study, we aimed to better understand this species to support sustainable management as there are uncertainties in some biological characteristics, like early growth and maturity. To this end, we teamed up with charter fishermen and scientists at South Carolina Department of Natural Resources and Old Dominion University to collect small blueline tilefish and learn more about their reproduction and growth. We discovered that the species' sex ratios favor females, deviating significantly from the expected 1:1 ratio in both the Southeast United States Atlantic (SEUS) and United States Mid-Atlantic (USMA) regions. Our research agreed with spawning seasons found in previous studies, which occur from April to October in the SEUS and from May to November in the USMA. It also may suggest that SEUS Blueline Tilefish still spawn in November. We also delved into age determination, a challenging aspect of fisheries science. While it remains a complex task, our agreement rates in age estimates were similar to the highest documented values. Our studies also suggested potential regional differences and sex differences in blueline tilefish growth. Additionally, we estimated that blueline tilefish mature at around 283 to 357 mm in total length and a few months to 3.6 years. We recommend further research into age determination and the collection of more young, small blueline tilefish. Overall, our studies shed light on the unique characteristics of blueline tilefish and highlights the need for continued research to better manage this species.
39

Apoptose du spermatozoïde et fertilité masculine

Brugnon, Florence 23 January 2009 (has links) (PDF)
Pour mieux comprendre la signification des marqueurs d'apoptose dans les spermatozoïdes éjaculés humains, l'objectif de notre étude était de mesurer ces marqueurs dans les spermatozoïdes prélevés à différents niveaux du tractus génital masculin dans différentes situations physiopathologiques. Pour évaluer la qualité fonctionnelle de ces spermatozoïdes, des relations ont été recherchées entre l'expression de ces marqueurs et les résultats obtenus en assistance médicale à la procréation. Les marqueurs analysés sont des facteurs mis en jeu dans l'initiation et l'activation de l'apoptose (poly-caspases, caspase-3, -8 ou -9 activée(s)), et des signes précoces (externalisation de la phosphatidylsérine, PS) ou tardifs (fragmentation de l'ADN) de l'apoptose. Pour certains échantillons, une analyse ultrastructurale des spermatozoïdes a aussi été réalisée. la mesure de l'expression des caspases activées a fait l'objet d'une mise au point compte-tenu de l'hétérogénéité des populations spermatiques et de la faible quantité de spermatozoïdes disponibles. Finalement, nous avons retenu une mesure par double marquage associant un inhibiteur fluorescent vert des caspases activées et un colorant fluorescent rouge (Propidium Iodide) avec une détection soit en cytométrie en flux soit en microscopie à fluorescence selon la nature des spermatozoïdes analysés. Chez des patients présentant une agénésie bilatérale des canaux déférents, la proportion de spermatozoïdes vivants ou morts exprimant des caspases activées est plus élevée dans les spermatozoïdes testiculaires que dans les spermatozoïdes épididymaires suggérant une initiation du processus apoptique dans les testicules et une incapacité des spermatozoïdes épididymaires à initier l'apoptose. Dans ces conditions, en ICSI, le risque d'injecter un spermatozoïde apoptique dans un ovocyte est plus élevé avec les spermatozoïdes testiculaires et pourrait expliquer pour une part, les résultats de moins bonne qualité avec ces spermatozoïdes testiculaires qu'avec les spermatozoïdes épididymaires. Chez des patients infertiles, porteurs d'une translocation chromosomique réciproque ou Robertsonienne autosomique, il existe une expression plus importante des modifications ultrastructurales et des marqueurs biochimiques d'apoptose (caspases activées, fragmentation de l'ADN, externalisation de la PS) associée à des signes d'immaturité ultrastructurale, comparé aux spermatozoïdes d'hommes fertiles. Ces résultats pourraient expliquer que dans l'éjaculat de ces patients, il existe une prédominance de gamètes équilibrés sur le plan chromosomique. En effet, les gamètes présentant un déséquilibre auraient été éliminées préférentiellement par apoptose. En conclusion, les marqueurs d'apoptose exprimés par les spermatozoïdes éjaculés seraient le reflet d'une altération de la spermatogenèse avec une apoptose initiée et avortée dans le testicule associée à des anomalies de maturation et différentiation. La mesure des marqueurs d'apoptose dans les spermatozoïdes apporterait une aide dans la compréhension et la prise en charge de l'infertilité masculine, en particulier en assistance médicale à la procréation.
40

Expression différentielle de la GPx5, un membre de la famille multigénique des glutathion peroxydases de mammifères

Zhang, Ting 12 June 2009 (has links) (PDF)
En utilisant des approches moléculaires variées, nous avons montré que le gène gpx5 possède au moins trois transcrits dans l'épididyme de souris adulte. A coté d'un messager long codant pour la protéine GPX5 mature, existent en effet deux transcrits tronqués. Les variants de la protéine GPx5, qui correspondent à ces transcrits courts, subissent dans l'épididyme de souris, une maturation post-transcriptionnelle qui repose essentiellement sur des processus de O-glycosylation. Ce travail a aussi permis de préciser que l'expression du gène gpx5 dépasse le territoire épididymaire puisque les transcrits gpx5 peuvent détectés à des niveaux faibles dans d'autres tissus de la sphère génitale chez la souris adulte. C'est le cas par exemple au niveau du testicule ou de la prostate. L'obtention, par des gestations datées, d'embryons de souris à différents stades, a permis de mettre en évidence une expression du gène gpx5 pendant les phases précoces du développement embryonnaire. Cette expression embryonnaire de gpx5 concerne un quatrième variant dont la séquence 3' UTR n'a pu être précisée. Des analyses immunohistochimiques complémentaires sont nécessaires pour confirmer la détection de la protéine GPx5 dans l'embryon précoce de souris et sa localisation dans l'endoderme pariétal.

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