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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.
41

Avaliação da atividade estrogênica das águas do Rio Paraíba do Sul / Evaluation of estrogenic activity in water samples from Paraiba do Sul River

Rocha, Guilherme Casoni da 14 December 2012 (has links)
A poluição da água doce no estado de São Paulo ocorre por diversas causas. Entre elas está a ineficiência do serviço de tratamento de esgoto sanitário. Alguns componentes do esgoto sanitário são desreguladores endócrinos, entre eles estão os hormônios naturais e sintéticos excretados pelos seres humanos. Estas substâncias causam modificações no sistema reprodutivo como, por exemplo, câncer, feminização, alterações na transcrição genética, alteração nas gônadas, indução à síntese de vitelogenina, entre outros. O objetivo desse trabalho foi testar a atividade endócrina das águas do rio Paraíba do Sul, em Pindamonhangaba, SP. Para tanto, amostras de água do rio foram utilizadas para a quantificação dos hormônios, 17-etinilestradiol, 17-estradiol e levonorgestrel por meio da técnica de cromatografia líquida de alta eficiência (HPLC). Além disso, foram realizados testes crônicos com peixes (Danio rerio) no interior do rio e em laboratório, e uma posterior quantificação de vitelogenina. Os resultados não indicaram concentrações detectáveis dos hormônios pelo método empregado. Entretanto, foi detectada a indução de vitelogenina nos machos de Danio rerio. Esse fato indica a atividade estrogênica da água utilizada. São necessários outros estudos para a avaliação de quais substâncias presentes na água, estão causando as alterações endócrinas nos peixes, entre eles a utilização de índices para priorizar o local inicial dessas pesquisas. Esses estudos são importantes para a conservação da biodiversidade aquática do rio Paraíba do Sul / Freshwater pollution in São Paulo state, Brazil, occurs due a several reasons. Among them there is the inefficiency of the sewage treatment service. Some sewage components are endocrine disrupters, including natural and synthetic hormones excreted by humans. These substances cause modification on reproductive system such as cancer, feminization, gene transcription and gonad alterations, vitellogenin synthesis induction, among others. The aim of this work was to evaluate the endocrine activity of the river Paraíba do Sul, at Pindamonhangaba city, Brazil. For this, river water samples were collected for the quantification of the hormones, 17- etinylestradiol, 17-estradiol and levonorgestrel by high performance liquid chromatography (HPLC). Furthermore, chronic assays were performed with fish (Danio rerio) into the river and in the laboratory, following quantification of biomarker vitellogenin. The studied hormones were not detected by employed methods. However, induction of vitellogenin in male of Danio rerio was detected indicating estrogenic activity of water. Further studies are necessary for the assessment of which substances into the water are causing the endocrine disruption in fish. These studies are important for the preservation of aquatic biodiversity of the Paraiba do Sul River
42

As proteínas do vitelo do nematoide entomopatogênico Heterorhabditis baujardi LPP7. / Purification and characterization of yolk proteins of the entomopathogenic nematode Heterorhabditis baujardi LPP7.

Carolina Rossi 05 November 2014 (has links)
Heterorhabditis é um gênero de nematoides entomopatogênicos, simbiontes de bactérias do gênero Photorhabdus. Juntos, infectam e matam artrópodes. A linhagem LPP7 de H. baujardi foi isolada na cidade de Monte Negro (RO). A vitelogênese compreende o acúmulo de reservas dentro do ovócito em crescimento. A vitelogenina é uma lipoproteína transportadora de lipídeos para o ovócito, formando o vitelo. Sequenciamos um fragmento de 800pb do gene vit-6 de LPP7, codificante do fim do polipeptídeo homólogo ao VT3 de O. tipulae ou ao YP88 de C. elegans. Seu transcrito possui 61% de identidade com VIT-6 de O. tipulae CEW1 e 46% de identidade com VIT-6 de C. elegans. As vitelogeninas purificadas de LPP7 mostram três bandas com pesos moleculares próximos às vitelogeninas de O. tipulae (VT1, VT2 e VT3). Mas, ao contrário do que foi mostrado em O. tipulae, onde a banda VT1 é apresenta um polipeptídeo, VT1 de LPP7 aparentemente contém um par de bandas com massas moleculares quase idênticas, como ocorre com a proteína YP170 de C. elegans. / Heterorhabditis is a genus of entomopathogenic nematodes that are associated with bacteria of the genus Photorhabdus. Together, they infect and kill arthropods. Heterorhabditis baujardi strain LPP7 was isolated in Monte Negro (RO). The yolk reserves are transported to the growing oocyte by a lipoprotein called vitellogenin. We have cloned and partially sequenced a fragment of 800pb of the vit-6 gene from LPP7. This fragment contains a portion of a homologous to those coding for the vitellins VT3 of O. tipulae and the YP88 C. elegans polypeptides. The polypeptide coded by the sequenced fragment showed that it has 61% identity to VIT-6 protein of O. tipulae CEW1 and 46% of identity to VIT-6 of C. elegans. The purified proteins of LPP7 show three bands with migrations close to the vitellins of O. tipulae (VT1, VT2 and VT3). However, unlike what was shown in O. tipulae where the VT1 band is comprised of a single polypeptide, LPP7 VT1 apparently contains a pair of bands with almost identical molecular masses as occurs with the homologous vitellin of C. elegans YP170.
43

Teleost reproduction: Aspects of Arctic char (<i>Salvelinus alpinus</i>) oocyte growth and maturation.

Berg, Håkan January 2003 (has links)
<p>In all vertebrate species, reproduction is a hormonally controlled process, important for growth and maturation of gonads and germ cells. Production of functional germ cells is of outmost importance to secure the survival of a species. Fish comprises 50% of the known vertebrates and are found in aquatic habitats all over the world. Even though fish have evolved a wide variety of morphological and physiological characteristics, due to large differences in the living environment, the growth an maturation of germ cells follows the same pattern in all species. In this thesis the focus has been directed on oocyte growth and development in Arctic char (Salvelinus alpinus), and if stress might inflict disturbances on the reproductive systems.</p><p>All sexually mature female egg laying vertebrates produces yolky eggs surrounded by an eggshell. Production of yolk and egg shell is under estrogenic control and it is known that production of egg components can be induced in male and juvenile fish by estrogenic substances. Many manmade chemicals have been found to interfere with hormonally controlled processes. Therefore production of the egg yolk precursor, vitellogenin (VTG), and the egg shell components, vitelline envelope proteins (VEP), have been used as biomarkers for estrogenic effect. Exposure to endocrine disrupting substances (EDS) does not only give rise to hormonal effects on the organism, but in addition it also gives rise to an increase in stress hormone, cortisol (F), levels. </p><p>It is evident that a wide variety of substances may affect Arctic char oocyte growth and maturation. VTG and VEP production is found to be under dose dependent estrogenic control, but the production was directly affected by F. Under natural condition it has been found that F increases towards ovulation. Even though both VTG and VTG is under estrogenic control, these studies showed that stress lead to a decrease of VTG while the VEP production increased. These effects was only observed on protein levels indicating that a post transcriptional down regulation of VTG production is mediated by F in Arctic char.</p><p>In order for an egg to become fertilizatible, it must undergo a maturation phase. This maturation phase is primarily induced by gonadotropins, which in turn induce the production of species specific maturation inducing substances (MIS). To investigate oocyte development in Arctic char a characterization of its MIS receptor was made. The MIS receptor is localized on the oocyte surface and displays a single class of high affinity and low capacity binding sites. The binding moieties displays association and dissociation kinetics typical of steroid membrane receptors.</p><p>Even though high specificity for Arctic char MIS was observed, it was found that some EDS bind to the Arctic char oocyte membrane receptor. This suggest that certain EDS might affect oocyte maturation and thereby might alter the reproductive success. Furthermore, it was found that F did not bind to the MIS receptor in Arctic char. It is therefore suggested that oocytes are more sensitive to stress during the growth phase than during maturation</p>
44

Teleost reproduction: Aspects of Arctic char (Salvelinus alpinus) oocyte growth and maturation.

Berg, Håkan January 2003 (has links)
In all vertebrate species, reproduction is a hormonally controlled process, important for growth and maturation of gonads and germ cells. Production of functional germ cells is of outmost importance to secure the survival of a species. Fish comprises 50% of the known vertebrates and are found in aquatic habitats all over the world. Even though fish have evolved a wide variety of morphological and physiological characteristics, due to large differences in the living environment, the growth an maturation of germ cells follows the same pattern in all species. In this thesis the focus has been directed on oocyte growth and development in Arctic char (Salvelinus alpinus), and if stress might inflict disturbances on the reproductive systems. All sexually mature female egg laying vertebrates produces yolky eggs surrounded by an eggshell. Production of yolk and egg shell is under estrogenic control and it is known that production of egg components can be induced in male and juvenile fish by estrogenic substances. Many manmade chemicals have been found to interfere with hormonally controlled processes. Therefore production of the egg yolk precursor, vitellogenin (VTG), and the egg shell components, vitelline envelope proteins (VEP), have been used as biomarkers for estrogenic effect. Exposure to endocrine disrupting substances (EDS) does not only give rise to hormonal effects on the organism, but in addition it also gives rise to an increase in stress hormone, cortisol (F), levels. It is evident that a wide variety of substances may affect Arctic char oocyte growth and maturation. VTG and VEP production is found to be under dose dependent estrogenic control, but the production was directly affected by F. Under natural condition it has been found that F increases towards ovulation. Even though both VTG and VTG is under estrogenic control, these studies showed that stress lead to a decrease of VTG while the VEP production increased. These effects was only observed on protein levels indicating that a post transcriptional down regulation of VTG production is mediated by F in Arctic char. In order for an egg to become fertilizatible, it must undergo a maturation phase. This maturation phase is primarily induced by gonadotropins, which in turn induce the production of species specific maturation inducing substances (MIS). To investigate oocyte development in Arctic char a characterization of its MIS receptor was made. The MIS receptor is localized on the oocyte surface and displays a single class of high affinity and low capacity binding sites. The binding moieties displays association and dissociation kinetics typical of steroid membrane receptors. Even though high specificity for Arctic char MIS was observed, it was found that some EDS bind to the Arctic char oocyte membrane receptor. This suggest that certain EDS might affect oocyte maturation and thereby might alter the reproductive success. Furthermore, it was found that F did not bind to the MIS receptor in Arctic char. It is therefore suggested that oocytes are more sensitive to stress during the growth phase than during maturation
45

Evaluation of Biomarker Responses in Fish : with Special Emphasis on Gill EROD Activity

Andersson, Carin January 2007 (has links)
Many chemicals present in the aquatic environment can interfere with physiological functions in fish. Exposure to chemicals can be revealed by the use of biomarkers. Induction of 7-ethoxyresorufin O-deethylase (EROD) activity is a commonly used biomarker for exposure to CYP1A inducers such as dioxins and polyaromatic hyrdrocarbons. Vitellogenin is a frequently used biomarker for estrogenic compounds in various fish species whereas a biomarker for androgens, spiggin, is only found in sticklebacks. The main objectives of this thesis were to evaluate gill EROD activity as a biomarker and the three-spined stickleback as a model species in ecotoxicological studies. EROD activities were measured in gill, liver and kidney in rainbow trout (Oncorhynchus mykiss) caged in urban areas in Sweden. EROD induction was most pronounced in the gill. Also in fish caged at reference sites, with an expected low level of known CYP1A inducers, a marked gill EROD induction was found. One suggested inducer in rural waters is humic substances (HS). To evaluate the EROD-inducing capacity of HS, three-spined sticklebacks (Gasterosteus aculeatus) were exposed to HS of natural or synthetic origin. Both kinds of HS caused significant EROD induction. Gill EROD activities were also induced in sticklebacks exposed to ethynylestradiol (EE2) and β-naphthoflavone (βNF), alone and in combinations. Production of vitellogenin was induced in sticklebacks exposed to ≥50 ng EE2/l and a significant decrease in spiggin production was observed in individuals exposed to 170 ng EE2/l. Results from this thesis further strengthen the contention that gill EROD activity is a very sensitive biomarker for CYP1A inducers and that the stickleback is a suitable biomonitoring species, especially for exposure to CYP1A inducers. The finding that not only classical CYP1A inducers but also HS and high EE2 concentrations stimulate gill EROD activity is of significance for the interpretation of biomonitoring data.
46

Avaliação da atividade estrogênica das águas do Rio Paraíba do Sul / Evaluation of estrogenic activity in water samples from Paraiba do Sul River

Guilherme Casoni da Rocha 14 December 2012 (has links)
A poluição da água doce no estado de São Paulo ocorre por diversas causas. Entre elas está a ineficiência do serviço de tratamento de esgoto sanitário. Alguns componentes do esgoto sanitário são desreguladores endócrinos, entre eles estão os hormônios naturais e sintéticos excretados pelos seres humanos. Estas substâncias causam modificações no sistema reprodutivo como, por exemplo, câncer, feminização, alterações na transcrição genética, alteração nas gônadas, indução à síntese de vitelogenina, entre outros. O objetivo desse trabalho foi testar a atividade endócrina das águas do rio Paraíba do Sul, em Pindamonhangaba, SP. Para tanto, amostras de água do rio foram utilizadas para a quantificação dos hormônios, 17-etinilestradiol, 17-estradiol e levonorgestrel por meio da técnica de cromatografia líquida de alta eficiência (HPLC). Além disso, foram realizados testes crônicos com peixes (Danio rerio) no interior do rio e em laboratório, e uma posterior quantificação de vitelogenina. Os resultados não indicaram concentrações detectáveis dos hormônios pelo método empregado. Entretanto, foi detectada a indução de vitelogenina nos machos de Danio rerio. Esse fato indica a atividade estrogênica da água utilizada. São necessários outros estudos para a avaliação de quais substâncias presentes na água, estão causando as alterações endócrinas nos peixes, entre eles a utilização de índices para priorizar o local inicial dessas pesquisas. Esses estudos são importantes para a conservação da biodiversidade aquática do rio Paraíba do Sul / Freshwater pollution in São Paulo state, Brazil, occurs due a several reasons. Among them there is the inefficiency of the sewage treatment service. Some sewage components are endocrine disrupters, including natural and synthetic hormones excreted by humans. These substances cause modification on reproductive system such as cancer, feminization, gene transcription and gonad alterations, vitellogenin synthesis induction, among others. The aim of this work was to evaluate the endocrine activity of the river Paraíba do Sul, at Pindamonhangaba city, Brazil. For this, river water samples were collected for the quantification of the hormones, 17- etinylestradiol, 17-estradiol and levonorgestrel by high performance liquid chromatography (HPLC). Furthermore, chronic assays were performed with fish (Danio rerio) into the river and in the laboratory, following quantification of biomarker vitellogenin. The studied hormones were not detected by employed methods. However, induction of vitellogenin in male of Danio rerio was detected indicating estrogenic activity of water. Further studies are necessary for the assessment of which substances into the water are causing the endocrine disruption in fish. These studies are important for the preservation of aquatic biodiversity of the Paraiba do Sul River
47

Développement de la mesure de la vitellogénine chez les invertébrés & utilisation de marqueurs de la perturbation endocrinienne chez le crustacé amphipode gammarus fossarum / Development of vitellogenin measurement in invertebrates & use of endocrine disrupting markers in the amphipod crustacea Gammarus Fossarum

Jubeaux, Guilaume 03 July 2012 (has links)
Parmi les substances polluantes, les perturbateurs endocriniens (PE) sont au coeur des préoccupations scientifiques en raison du risque de ces composés pour l'environnement, et en particulier les écosystèmes aquatiques. L'étude de la disponibilité et de l'impact des PE sur les vertébrés aquatiques, en particulier les poissons, a fait l'objet de nombreux projets et publications. Ces travaux ont conduit au développement d'outils de diagnostic pouvant être utilisés in situ, comme par exemple l'induction de la vitellogénine (Vg) chez les mâles, l'inhibition de la croissance ovarienne et testiculaire, le retard dans la maturité sexuelle, la présence d'individus intersexués et les concentrations anormales en hormones stéroïdiennes. En revanche, peu d'attention a été portée aux invertébrés qui représentent pourtant plus de 95 % des espèces animales et jouent un rôle essentiel dans le fonctionnement et la santé des écosystèmes aquatiques. Par conséquent, il en résulte un manque d'outils spécifiques de la perturbation endocrinienne chez ces espèces. Dans ce contexte, le travail proposé se focalise tout d'abord sur l'intérêt et la pertinence de la spectrométrie de masse (LC-MS/MS) pour développer ou transférer entre espèces une méthode de mesure de la Vg chez les invertébrés, incluant les crustacés, les mollusques et les insectes. Ensuite, ce travail s'est intéressé à un crustacé amphipode modèle (Gammarus fossarum) et avait pour objectifs (1) de développer le biomarqueur Vg, via la validation de son rôle fonctionnel dans la reproduction (vitellogenèse, embryogenèse et différences inter-sexe), de sa sensibilité à des composés modèles et jusqu'à son utilisation dans le cadre d'études de terrain à l'aide d'organismes encagés et (2) de développer l'utilisation d'une approche chez la femelle permettant de caractériser le potentiel PE de composés et des systèmes aquatiques, à partir de l'étude de marqueurs individuels / Among pollutants, endocrine disruptors (ED) are in central scientific preoccupation because of the risks of these compounds to the environment, in particular for aquatic ecosystems. The availability and impact study of ED on aquatic vertebrates, in particular fishes, was the subject of many projects and papers. These studies led to the development of diagnostic tools, such as vitellogenin (Vg) induction in male organisms, inhibition of ovarian and testicular growth, delayed sexual maturity, presence of intersex individuals and abnormal concentrations of steroid hormones. However, little attention was paid to invertebrates which account for more than 95% of animal species and play an essential role in functioning and health of aquatic ecosystems. Therefore, the result is a lack of specific tools for endocrine disruption assessment in these species. In this context, the proposed work focuses first on the interest and relevance of mass spectrometry (LC-MS/MS) to develop and to transfer among species a method for measuring Vg in invertebrates species, including crustaceans, molluscs and insects. Then, this work has focused on a model amphipod crustacean (Gammarus fossarum) and aims were (1) to develop the Vg biomarker, through the validation of its functional role in reproduction (vitellogenesis, embryogenesis and inter-sex differences), its sensitivity towards model compounds and to its use in field monitoring, using caged organisms and (2) develop a biotest in the female to assess the ED risk of chemical compounds and aquatic systems, by studying and measuring individual markers
48

Effects of Five Substances with Different Modes of Action on Cathepsin H, C and L Activities in Zebrafish Embryos

Küster, Eberhard, Kalkhof, Stefan, Aulhorn, Silke, von Bergen, Martin, Gündel, Ulrike 06 April 2023 (has links)
Cathepsins have been proposed as biomarkers of chemical exposure in the zebrafish embryo model but it is unclear whether they can also be used to detect sublethal stress. The present study evaluates three cathepsin types as candidate biomarkers in zebrafish embryos. In addition to other functions, cathepsins are also involved in yolk lysosomal processes for the internal nutrition of embryos of oviparous animals until external feeding starts. The baseline enzyme activity of cathepsin types H, C and L during the embryonic development of zebrafish in the first 96 h post fertilisation was studied. Secondly, the effect of leupeptin, a known cathepsin inhibitor, and four embryotoxic xenobiotic compounds with different modes of action (phenanthrene—baseline toxicity; rotenone—an inhibitor of electron transport chain in mitochondria; DNOC (Dinitro-ortho-cresol)—an inhibitor of ATP synthesis; and tebuconazole—a sterol biosynthesis inhibitor) on in vivo cathepsin H, C and L total activities have been tested. The positive control leupeptin showed effects on cathepsin L at a 20-fold lower concentration compared to the respective LC50 (0.4 mM) of the zebrafish embryo assay (FET). The observed effects on the enzyme activity of the four other xenobiotics were not or just slightly more sensitive (factor of 1.5 to 3), but the differences did not reach statistical significance. Results of this study indicate that the analysed cathepsins are not susceptible to toxins other than the known peptide-like inhibitors. However, specific cathepsin inhibitors might be identified using the zebrafish embryo.
49

Assessment of the Efficacy of a Constructed Wetland to Reduce or Remove Wastewater Effluent Estrogenicity and Toxicity Using Biomarkers in Male Fathead Minnows (Pimephales Promelas Rafinesque, 1820)

Hemming, Jon M. 12 1900 (has links)
Vitellogenin in Pimephales promelas was used to assess estrogenicity of a local municipal effluent. Vitellogenin induction in male P. promelas increased in frequency and magnitude with increased exposure duration and was greater ("=0.05) than controls after 2 and 3 weeks of exposure. The level of vitellogenesis induced by effluent exposure was high compared to similar studies. A spring season evaluation followed. Biomarkers in P. promelas were used to assess the efficacy of a treatment wetland to remove toxicity and estrogenicity in final treated wastewater effluent. Comparisons were made with an effluent dominated stream and laboratory controls. Vitellogenin, GSIs (gonado-somatic indices), HSIs (hepato-somatic indices) and secondary sexual characteristics were biomarkers used in P. promelas models to assess aqueous estrogenicity. Biological indicators used to assess general fish health included hematocrit and condition factors. The estrogenic nature of the effluent was screened, concurrent with fish exposure, with GC/MS analysis for target estrogenic compounds including: 17-b estradiol, estrone, ethynylestradiol, Bisphenol A, nonylphenolic compounds, phthalates, and DDT. Plasma vitellogenin measured in P. promelas was significantly elevated (p < 0.0001) at the inflow site of the wetland and stream sites. GSIs for these exposures were less (a=0.001) at the wetland inflow site. At wetland sites closest to the inflow, secondary sexual charateristics, tubercle numbers and fat pad thickness, were less (a=0.0001). Hematocrit and condition factors were less (a=0.001) at sites closer to the wetland inflow. Seasonal variation was examined by repeating the effluent characterization in summer. Additionally, summer testing included exposure to an effluent dilution series. Fish condition heavily influenced interpretation of the results. Pre-acclimation exposure to spawning stresses may have altered many of the biological markers measured. Results are discussed relative to fish health and pre-exposure environment. Toxicity assessed with P. promelas biomarkers was compared with Ceriodaphnia dubia and Vibrio fischeri toxicty tests on this effluent. Biomarkers of fish health were somewhat less sensitive than C. dubia test endpoints, but more sensitive than V. fisheri.
50

Estudo das vitelinas VT1 e YP170B dos nematoides rabditídeos Oscheius tipulae e Caenorhabditis elegans: aspectos estruturais e funcionais. / Structural and functional analysis of VT1 and YP170B vitellins from the Rhabditid nematodes Oscheius tipulae and Caenorhabditis elegans.

Almenara, Daniela Peres 07 July 2009 (has links)
A região N-terminal de OTI-VIT-1 foi expressa e os polipeptídeos recombinantes foram purificados. OTI-VIT-1 pode ser homólogo da vitelina YP170B de C. elegans. Foram identificados um intron na região 5´ e dois na região 3´ do gene Oti-vit-1. Antissoro monoespecífico para PVIT1HisC confirmou que o gene Oti-vit-1 codifica VT1. O polipeptídeo recombinante P40-H, correspondente à região N-terminal da proteína OTI-VIT-6 interage com um polipeptídeo de aproximadamente 100 kDa (P100) presente em extratos proteicos totais de O. tipulae. Estudamos também o papel da Proteína Microssômica Transportadora de Triglicerídeos (MTP) na biossíntese de Vitelogenina do nematoide C. elegans. Ensaios de RNAi em C. elegans, utilizando parte da sequência do gene da MTP (Cel-dsc-4) foram realizados nas linhagens N2 e DH1033. Microscopia de fluorescência de vermes adultos da linhagem DH1033, submetidos a RNAi, mostrou acúmulo de YP170B::GFP no interior dos enterócitos. Este acúmulo sugere a participação da MTP na secreção de VTG. Análise imunológica da vitelogenina nestes mesmos vermes não detectaram alterações no processamento de CEL-VIT-6, sugerindo que o mesmo ocorra não só no pseudoceloma, mas também no interior dos enterócitos. / The N-terminal region of OTI-VIT-1 was expressed and the recombinant polypeptides were purified. OTI-VIT-1 may be homologous to the vitellin YP170B from C. elegans. We identified an intron in the 5 \'region and two in 3\' region from Oti-vit-1. Monospecific antisera to PVIT1HisC confirmed that the gene Oti-vit-1 encodes VT1. The recombinant polypeptide P40-H, corresponding to the N-terminal region of the protein OTI-VIT-6, interacts with a polypeptide of approximately 100 kDa (P100) present in total protein extracts of O. tipulae. The role of microsomal triglyceride transfer protein (MTP) in the biosynthesis of vitellogenin was studied in the nematode C. elegans. Trials of RNAi in C. elegans, using the sequence of the MTP gene (Cel-dsc-4) were performed in the strains N2 and DH1033. Fluorescence microscopy of adult worms of strain DH1033, subjected to RNAi, showed accumulation of YP170B:: GFP within the enterocytes. This accumulation suggests the involvement of MTP in the secretion of VTG. Analysis using anti-vitellogenin immune serum did not detect changes in the processing of CEL-VIT-6, suggesting that it occurs not only in pseudocoelom but also within the enterocytes.

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