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Auswahl der wissenschaftlichen Literatur zum Thema „Embryons non-C“
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Zeitschriftenartikel zum Thema "Embryons non-C"
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Isermann, B., S. B. Hendrickson, K. Hutley, M. Wing und H. Weiler. „Tissue-restricted expression of thrombomodulin in the placenta rescues thrombomodulin-deficient mice from early lethality and reveals a secondary developmental block“. Development 128, Nr. 6 (15.03.2001): 827–38. http://dx.doi.org/10.1242/dev.128.6.827.
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The endothelial cell surface receptor thrombomodulin (TM) inhibits blood coagulation by forming a complex with thrombin, which then converts protein C into the natural anticoagulant, activated protein C. In mice, a loss of TM function causes embryonic lethality at day 8.5 p.c. (post coitum) before establishment of a functional cardiovascular system. At this developmental stage, TM is expressed in the developing vasculature of the embryo proper, as well as in non-endothelial cells of the early placenta, giant trophoblast and parietal endoderm. Here, we show that reconstitution of TM expression in extraembryonic tissue by aggregation of tetraploid wild-type embryos with TM-null embryonic stem cells rescues TM-null embryos from early lethality. TM-null tetraploid embryos develop normally during midgestation, but encounter a secondary developmental block between days 12.5 and 16.5 p.c. Embryos lacking TM develop lethal consumptive coagulopathy during this period, and no live embryos are retrieved at term. Morphogenesis of embryonic blood vessels and other organs appears normal before E15. These findings demonstrate a dual role of TM in development, and that a loss of TM function disrupts mouse embryogenesis at two different stages. These two functions of TM are exerted in two distinct tissues: expression of TM in non-endothelial extraembryonic tissues is required for proper function of the early placenta, while the absence of TM from embryonic blood vessel endothelium causes lethal consumptive coagulopathy.
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Abecia, J. A., F. Forcada, I. Palacín, L. Sánchez-Prieto, C. Sosa, A. Fernández-Foren und A. Meikle. „Undernutrition affects embryo quality of superovulated ewes“. Zygote 23, Nr. 1 (09.10.2013): 116–24. http://dx.doi.org/10.1017/s096719941300035x.
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SummaryTo determine the effect of undernutrition on embryo production and quality in superovulated sheep, 45 ewes were allocated into two groups to be fed diets that provided 1.5 (control, C; n = 20) or 0.5 (low nutrition, L; n = 25) times daily requirements for maintenance, from oestrous synchronization with intravaginal sponges to embryo collection. Embryos were collected 7 days after the onset of oestrus (day 0). Low nutrition resulted in lower live weight and body condition at embryo collection (P < 0.05). Diet (P < 0.01) and day of sampling (P < 0.001) significantly affected plasma non-esterified fatty acid (NEFA) and insulin concentrations. Plasma leptin concentrations decreased on day 7 only in L ewes. A significant effect of dietary treatment (P < 0.05) and day (P < 0.0001) was observed on plasma insulin-like growth factor (IGF)-I concentrations. The number of recovered oocytes and embryos did not differ between the groups (L: 15.4 ± 0.4; C: 12.4 ± 0.4). Recovery rate was lower (P < 0.05) in the L (60%) than in the C group (73%). The total number of embryos and number of viable-transferable embryos (5.0 ± 0.3 and 3.4 ± 0.3 embryos, respectively) of the L group were lower (P < 0.1) when compared with controls (8.4 ± 0.4 and 6.2 ± 0.4 embryos, respectively). Undernutrition during the period of superovulation and early embryonic development reduced total and viable number of embryos. These effects might be mediated by disruption of endocrine homeostasis, oviduct environment and/or oocyte quality.
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Tuska, Habib Syaiful Arif, Nursalsabila Khamalt, Muhammad Arfan Lesmana, Reza Yesica, Viski Fitri Hendrawan, Budiono und Gretania Residiwati. „Effect of Artemisia vulgaris Supplementation on Zebrafish Embryo Under Heat Stress Condition during In Vitro Culture“. Journal of Applied Veterinary Science And Technology 5, Nr. 1 (30.04.2024): 20–25. http://dx.doi.org/10.20473/javest.v5.i1.2024.20-25.
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Background: Artemisia vulgaris contains flavonoids, which play a vital role in counteracting free radicals. Purpose: To determine the effect of Artemisia vulgaris extract supplementation on embryo development, heart rate and survival of zebrafish under heat stressed and non-heat stressed conditions. Methods: The research used a completely randomized design. Zebrafish embryos (n=240) were divided into heat stressed (36°C) and non-heat stressed (28°C) groups, while for each group were divided into three subgroups, namely T1/control (without Artemisia vulgaris supplementation); and supplemented group T1 and T2, with 2 µL and 4 µL of Artemisia vulgaris supplementation, respectively. The efficacy of Artemisia vulgaris supplementation was determined by observing the embryo development, heart rate, and survival rate of zebrafish up to 96 hours post fertilization (hpf). Results: The development of zebrafish embryos under heat stressed treated with Artemisia vulgaris extract gave the same quality as the control treatment without heat stressed exposure. Zebrafish embryos exposed to heat stressed with 4 µL Artemisia vulgaris supplementation gave the highest survival rate on the heat stressed group. Artemisia vulgaris supplementation improved the heart rate of zebrafish exposed to heat stressed as in the non-heat stressed group. Conclusion: Artemisia vulgaris extract can reduce the detrimental effects of heat stressed induction on zebrafish embryos, as evidenced by the improvement in embryonic development, heart rate, and survival rate of zebrafish embryos after supplementation.
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Fieni, F., M. Oseikria, K. Laroucau, F. Vorimore, D. Tainturier, S. Destrumelle und J. L. Pellerin. „111 RISK OF CHLAMYDIA ABORTUS TRANSMISSION VIA EMBRYO TRANSFER USING IN VITRO EARLY BOVINE EMBRYOS“. Reproduction, Fertility and Development 28, Nr. 2 (2016): 186. http://dx.doi.org/10.1071/rdv28n2ab111.
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Chlamydia abortus (C. abortus) in cattle has been reported sporadically throughout the world and is implicated in respiratory, ocular, and reproductive disease as abortion, infertility, chronic mastitis, vaginal discharge, and endometritis. In addition, C. abortus presents a zoonotic risk exposure of pregnant women to infected animal and can lead to severe septicaemia in the mother, resulting in spontaneous abortion or stillbirth of the fetus. To investigate the risk of C. abortus transmission via bovine embryo transfer, our study aims to determine whether the embryonic ZP of in vitro-produced embryos protects early embryo cells against C. abortus infection and whether the bacteria adhere to or infect the cells of early bovine embryos (ZP-free) after in vitro infection. We also evaluated the efficacy of the washing procedure recommended by the IETS to decontaminate bovine embryos exposed to C. abortus in vitro. Ninety (8 to 16 cells) bovine embryos, produced in vitro, were randomly divided into 10 batches. Eight batches (4 ZP-intact and 4 ZP-free) of 10 embryos were incubated in a medium containing 4.8 × 107 Chlamydia/mL of AB7 strain (ANSES, Maisons-Alfort, France). After incubation for 18 h at 37°C in an atmosphere of 5% CO2, the embryos were washed in batches in 10 successive baths of a PBS and 5% FCS solution without trypsin nor antibiotics in accordance with IETS guidelines. In parallel, 2 batches of 5 embryos (1 ZP-intact and 1 ZP-free) were subjected to similar procedures but without exposure to C. abortus as a control group. The 10 washing fluids from each batch were collected and centrifuged for 1 h at 13 000 × g. The embryos and wash pellets were tested using RT-PCR. Chlamydia abortus DNA was found in all ZP-intact and ZP-free infected embryos after 10 successive washes. It was also detected in the tenth wash fluid for 1 batch (1/4) of ZP-intact infected embryos and in 3 batches (3/4) of ZP-free infected embryos. In contrast, none of the embryos or their washing fluids in the control batches was DNA positive. These results demonstrate that C. abortus adheres to or penetrates the ZP as well as the early embryonic cells of in vitro-produced bovine embryos after in vitro infection, and that the standard washing protocol recommended by the IETS failed to remove it. The persistence of these bacteria after washing makes the embryo a potential means of transmission of the bacterium during embryo transfer from infected donor cows to healthy recipients or their offspring. Nevertheless, the finding of C. abortus DNA by RT-PCR did not imply that the bacteria found is still infective. Further studies are required to investigate whether enzymatic or antibiotic treatment of bovine embryos infected by C. abortus would eliminate the bacteria from the ZP.
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Pellerin, J. L., A. Ashraf, M. Oseikria, K. Laroucau, F. Vorimore, C. Roux, M. Larrat, S. Michaud und F. Fieni. „162 CAN CHLAMYDIA ABORTUS BE TRANSMITTED BY EMBRYO TRANSFER IN GOATS?“ Reproduction, Fertility and Development 27, Nr. 1 (2015): 172. http://dx.doi.org/10.1071/rdv27n1ab162.
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Chlamydia abortus is a gram-negative obligate intracellular bacterium. Its lifecycle includes a resistant infectious form and a metabolically active non-infectious form. Chlamydia abortus infection results in abortion in goats; in nonpregnant animals the infection is usually subclinical. Chlamydia abortus presents a major zoonotic risk for pregnant women. The aim of this study was to investigate whether the embryonic zona pellucida (ZP) protects early embryo cells from infection and to test the efficacy of the washing protocol recommended by the IETS for bovine embryos. The study was performed in triple replicate: 14 donor goats, certified negative by ELISA and PCR to C. abortus, were synchronized, superovulated, and subsequently inseminated by males controlled negative for C. abortus. Fifty-two ZP-intact embryos (8–16 cells) were collected 4 days later, by laparotomy. The embryos were randomly divided into 12 batches. Nine batches of 5 embryos were incubated in a medium containing 4 × 107 Chlamydia mL–1, AB7 strain. After incubation for 18 h at 37°C in an atmosphere of 5% CO2, the embryos were washed in batches in 10 successive baths of PBS and 5% FCS solution in accordance with IETS guidelines for bovine embryos. In parallel, 3 batches of ZP-intact embryos (2, 2, and 3 embryos in the first, second, and third batches, respectively) were used as controls by being subjected to similar procedures, but without exposure to C. abortus. The 10 wash baths were collected separately and centrifuged for 1 h at 13 000 × g. The washed embryos and the pellets of the 10 centrifuged wash baths were frozen at –20°C before examination for evidence of C. abortus using RT-PCR. Chlamydia abortus DNA was found in all batches of infected ZP-intact embryos (9/9) after 10 successive washes. It was also detected in the tenth wash fluid for 4 batches (4/9) of infected embryos. As expected, none of the embryos or their washing fluids in the control batches were DNA positive. These results demonstrate that C. abortus adheres to and/or penetrates the ZP of in vivo caprine embryos after in vitro infection, and that the standard washing protocol recommended by the IETS for bovine embryos failed to remove it. The persistence of these bacteria after washing makes the embryo a potential means of transmission of the bacterium during embryo transfer from infected donor goat to healthy recipients and/or their offspring. Further studies are required to investigate whether enzymatic and/or antibiotic treatment of infected caprine embryos can eliminate C. abortus from the ZP.
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Gentles, R., und C. O'Neill. „340. ANALYSIS OF PROTEINS SECRETED BY THE PREIMPLANTATION MOUSE EMBRYO“. Reproduction, Fertility and Development 22, Nr. 9 (2010): 140. http://dx.doi.org/10.1071/srb10abs340.
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Many embryos generated by assisted reproductive technologies do not have the capacity for full development. A non-destructive test that allows the most viable embryos to be identified would allow development of a range of strategies to improve these technologies. Analysis of the proteinaceous secretome of the preimplantation mouse embryo by electrospray mass spectrometry of tryptic digests of embryo-conditioned culture media identified 20 peptides.1 Lactate dehydrogenase beta (LDH) and protein disulfide isomerase (PDI) were consistently among the most abundant peptides identified. PDI has been found to be secreted and surface expressed in a number of other cell types suggesting a biologically significant role. LDH-beta is a marker of plasma membrane integrity and is widely used in medicine for assessment of cardiac health. The aim of this study was to assess the expression of these proteins in the early embryo to gain some understanding of the potential significance of their presence within the embryonic secretome. Zygotes (B6CBF2) were collected 20–22 h post hCG. They were cultured in groups of 10 embryos for 96 h in 10 mL of modHTF 30 µg BSA/mL media. Embryonic protein was extracted for western blot analysis or embryos subjected were to immunolocalization studies for PDI and LDH. Western blot analysis revealed presence of proteins of expected molecular mass. Staining for both proteins occurred at high levels at each stage of development throughout pre-implantation development. Staining was predominantly cytoplasmic and excluded from nuclei. Cultured blastocysts had less LDH than fresh but the level for PDI was similar for both. Staining of non-permeabilized embryos revealed extracellular staining of PDI. The results show high levels of cellular expression of two proteins reported to be released by the embryo in vitro. (1) Beardsley A, Li Y, O’Neill C (2010). Characterization of a diverse secretome generated by the mouse preimplantation embryo in vitro. Reproductive Biology and Endocrinology 8, 71.
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Alsaleh, A., J. L. Pellerin, C. Roux, M. Larrat, G. Chatagnon und F. Fieni. „166 CAN COXIELLA BURNETII BE TRANSMITTED BY GOAT EMBRYO TRANSFER?“ Reproduction, Fertility and Development 25, Nr. 1 (2013): 231. http://dx.doi.org/10.1071/rdv25n1ab166.
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Coxiella burnetii, an obligate intracellular bacterium of worldwide distribution, is responsible for Q fever. Detection of significant bacterial loads in flushing media and tissue samples (oviducts and uterine horns) from the genital tracts of nonpregnant goats is a risk factor for in utero infection and transmission during embryo transfer (Alsaleh et al. 2011 CIMID 34, 355–360). The aim of this study was to investigate (1) whether cells of early goat embryos isolated from in vivo fertilized goats interact with C. burnetii in vitro, (2) whether the embryonic zona pellucida (ZP) protects early embryo cells from infection, and (3) the efficacy of the washing protocol recommend by the IETS for bovine embryos. The study was performed in triple replicate: 12 donor goats, certified negative by ELISA and PCR, were synchronized, superovulated, and subsequently inseminated by Q fever-negative males. Sixty-eight embryos were collected 4 days later by laparotomy. Two-thirds of the resulting ZP-intact and ZP-free 8- to 16-cell embryos (9–9, 11–11, and 4–4 in replicates 1, 2, and 3, respectively) were placed in 1 mL of MEM containing 107 C. burnetii CBC1 (IASP, INRA Tours). After overnight incubation at 37°C and 5% CO2, the embryos were washed according to the IETS procedure. In parallel, the remaining third ZP-intact and ZP-free uninfected embryos (3–3, 5–5, and 2–2 in replicates 1, 2, and 3, respectively) were submitted to the same procedures but without C. burnetii, thus serving as controls. The 10 washing fluids for all batches of each replicate were collected and centrifuged for 1 h at 13 000g. The washed embryos and pellets were tested by PCR. Coxiella burnetii DNA was found in all batches of ZP-intact and ZP-free infected embryos after 10 successive washes. It was also detected in the first 5 washing fluids for ZP-free embryos and in the first 8 washing fluids for ZP-intact embryos. None of the control batches (embryos and washing fluids) were found to contain bacterial DNA. These results clearly demonstrate that caprine early embryonic cells are susceptible to infection by C. burnetii. The bacterium shows a strong tendency to cling to the ZP after in vitro infection, and the washing procedure recommended by the IETS for bovine embryos failed to remove it. The persistence of these bacteria makes the embryo a potential means of transmission to recipient goats. Further studies are needed to investigate whether the enzymatic treatment of caprine embryos infected by C. burnetii would eliminate the bacteria from the ZP.
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Martinez, Cristina A., Marie Rubér, Heriberto Rodriguez-Martinez und Manuel Alvarez-Rodriguez. „Pig Pregnancies after Transfer of Allogeneic Embryos Show a Dysregulated Endometrial/Placental Cytokine Balance: A Novel Clue for Embryo Death?“ Biomolecules 10, Nr. 4 (05.04.2020): 554. http://dx.doi.org/10.3390/biom10040554.
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Pig embryo transfer (ET) is burdened by high embryo mortality, with cytokines playing a significant role in recruitment of immune cells during embryo attachment and placentation. We hereby tested if their levels in endometrium and placenta from sows carrying hemi-allogeneic (artificially inseminated sows; C+ positive control) or allogeneic embryos (sows subjected to ET; ET) during peri-implantation (D18) or post-implantation (D24) are suitable mirrors of embryo rejection or tolerance after ET. Non-pregnant sows (C−) were used as negative controls. A set of cytokines was assayed in the tissues through multiplexed microsphere-based flow cytometry (Luminex xMAP, Millipore. USA). Fewer (58.7%. p < 0.003) conceptuses were recovered at D24 after ET compared to C+ (80.9%); with more than 20% of the ET conceptuses being developmentally delayed. Cytokine levels shifted during implantation. Anti-inflammatory IL-10 levels were significantly (p < 0.05) lower in ET sows compared to C+ at D24 of pregnancy. The C+ controls (carrying hemi-allogeneic embryos) consistently showed higher levels of pro-inflammatory TNF-α, IFN-γ, and IL-2 cytokines at D18 and IL-1α at D24, compared to the ET group. This clear dysregulation of pro- and anti-inflammatory cytokine levels in sows subjected to ET could be associated with an impaired maternal immune tolerance, explaining the high embryonic mortality of ET programs.
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Abdul Rahman, Nor-Shahida, Nor-Ashikin Mohamed Noor Khan, Zolkapli Eshak, Mimi-Sophia Sarbandi, Aqila-Akmal Mohammad Kamal, Mastura Abd Malek, Fathiah Abdullah, Maizaton Atmadini Abdullah und Fezah Othman. „Exogenous L-Glutathione Improves Vitrification Outcomes in Murine Preimplantation Embryos“. Antioxidants 11, Nr. 11 (25.10.2022): 2100. http://dx.doi.org/10.3390/antiox11112100.
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Vitrification is an important tool to store surplus embryos in assisted reproductive technology (ART). However, vitrification increases oxidative damage and results in decreased viability. Studies have reported that L-glutathione (GSH) supplementation improves the preimplantation development of murine embryos. Glutathione constitutes the major non-protein sulphydryl compound in mammalian cells, which confers protection against oxidative damage. However, the effect of GSH supplementation on embryonic vitrification outcomes has yet to be reported. This study aims to determine whether GSH supplementation in culture media improves in vitro culture and vitrification outcomes, as observed through embryo morphology and preimplantation development. Female BALB/c mice aged 6–8 weeks were superovulated through an intraperitoneal injection of 10 IU of pregnant mare serum gonadotrophin (PMSG), followed by 10 IU of human chorionic gonadotrophin (hCG) 48 h later. The mated mice were euthanized by cervical dislocation 48 h after hCG to harvest embryos. Two-cell embryos were randomly assigned to be cultured in either Group 1 (GSH-free medium), Group 2 (GSH-free medium with vitrification), Group 3 (0.01 mM GSH-supplemented medium), or Group 4 (0.01 mM GSH-supplemented medium with vitrification). Non-vitrified (Groups 1 and 3) and vitrified (Groups 2 and 4) embryos were observed for morphological quality and preimplantation development at 24, 48, 72, and 96 h. In the non-vitrified groups, there were significant increases in the number of Grade-1 blastocysts in GSH cultures (p < 0.05). Similarly, in the vitrified groups, GSH supplementation was also seen to significantly increase blastocyst formation. Exogenous GSH supplementation resulted in a significant increase in intracellular GSH, a release of cytochrome c from mitochondria, and a parallel decrease in intracellular reactive oxygen species (ROS) levels in vitrified eight-cell embryos (p < 0.05). GSH supplementation was shown to upregulate Bcl2 expression and downregulate Bax expression in the vitrified preimplantation embryo group. The action of exogenous GSH was concomitant with an increase in the relative abundance of Gpx1 and Sod1. In conclusion, our study demonstrated the novel use and practical applicability of GSH supplementation for improving embryonic cryotolerance via a decrease in ROS levels and the inhibition of apoptotic events by improvement in oxidative status.
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Coutinho, A. R. S., M. P. Milazzotto, M. A. Peres, M. G. Marques, A. C. Nicacio, J. A. Visintin und M. E. O. A. Assumpção. „273 APOPTOSIS EVALUATION OF IN VITRO-PRODUCED PIG EMBRYOS (PARTIAL RESULT)“. Reproduction, Fertility and Development 18, Nr. 2 (2006): 244. http://dx.doi.org/10.1071/rdv18n2ab273.
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Apoptosis is a physiological event involved with death and tissue replication, fulfilling an important function of tissue organizations during embryogenesis. This mechanism occurs in in vivo as well as in vitro pre-implantation embryos, but most frequently in the latter. The transcriptional activation of pig embryos occurs at the four-cell stage, which is the longer stage during the pre-implantation period. This stage is characterized by embryonic developmental blockage that decreases the production rates (embryos loss). The aim of this study was to evaluate a correlation between apoptosis mechanism and developmental blockage of IVP porcine embryos. Immature oocytes after IVM/IVF were submitted to IVC in PZM-1 medium containing BSA 3 mg/mL at 38.5�C, 5% CO2 in air and high humidified atmosphere. The embryo development was analyzed at 96 h of cultute (Day 4) in order to verify cleavage rate and blockage (4 cells) and non-blockage (e8 cells) embryo rates. Out of 625 grade I, II, and III oocytes submitted to IVP, 70.3 � 5.2% (430/625) cleaved from which 27.1 � 10.3% (166/625) were blocked and 43 � 10.8% (264/625) were non-blocked. Blocked and non-blocked embryos were assessed to evaluate apoptosis rates. Qualitative assays of embryo cells were achieved with two different DNA stains: YOPRO-1 (Molecular Probe�; Invitrogen Brasil, Ltd., Sao Paulo, Brazil), permeable though plasma membrane in the early stage of apoptosis, and TUNEL (Roche�; Amersham Biosciences, Sao Paulo, Brazil), which detects DNA fragmentation in the last stages of apoptosis. The embryos were stained with 0.1 �M YOPRO-1/mL PBS, incubated 15 min at 38�C, 5% CO2 in air and high humidified atmosphere, and immediately observed by means of confocal microscopy. For the TUNEL assay, embryos were fixed in 4% paraformaldehyde solution (w/v) in PBS for 1 h at room temperature, and incubated in permeabilization solution [0.5% (v/v) Triton X-100, 0.1% (w/v) sodium citrate in PBS] for 2 h. For positive control, samples were treated with DNase-I at 37�C for 1 h. The negative control and experimental samples were incubated with buffer solution under the same conditions. The positive control and experimental samples were incubated with enzymatic and stain solution (FITC) at 37�C for 1 h; the negative control was incubated with only enzymatic solution. The embryos were stained with Hoechst 33342 (5 �/mL) and observed by means of fluorescence microscopy. Blocked embryos showed more apoptosis (66% and 40% to YOPRO-1 and TUNEL, respectively) than non-blocked embryos (25% and 0% to YOPRO-1 and TUNEL, respectively). In conclusion, the developmentally blocked embryos suffered more apoptosis, although morphologic apoptosis assays (light and electronic microscopic) must be performed to confirm this finding. This work was supported by FAPESP 04/01252-4.
Dissertationen zum Thema "Embryons non-C"
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Samandar, eweis Dureen. „Asymmetric division in single cell nematode embryos outside the Caenorhabditis genus“. Electronic Thesis or Diss., Université Paris sciences et lettres, 2021. http://www.theses.fr/2021UPSLS063.
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La division cellulaire asymétrique est un processus essentiel du développement. Ce processus ainsi que sa régulation ont fait l’objet de nombreuses études chez l’embryon de Caenorhabditis elegans. La division asymétrique de l'embryon unicellulaire est un processus conservé à travers les espèces de nématodes, cependant les caractéristiques cellulaires menant à la division sont étonnamment variables. Au cours de mon doctorat, j'ai voulu étudier ces différences en utilisant deux embryons non-C. elegans : Diploscapter pachys et Pristionchus pacificus. D. pachys est le parent parthénogénétique le plus proche de C. elegans. La polarité étant induite par le sperme chez C. elegans, on ne peut expliquer ce qui brise la symétrie chez D. pachys. Mes résultats montrent que le noyau occupe le plus souvent l’hémisphère de D. pachys qui deviendra le pole postérieur. Dans les embryons où il est astreint à un pôle par centrifugation, le noyau fini par revenir à son pôle préférentiel. Même si l’embryon est polarisé, l’agitation corticale et le cytosquelette d’actine semblent identiques aux deux pôles. D’autre part, la position du fuseau méiotique est corrélée avec la future cellule postérieure. Dans certains ovocytes, on observe des structures de microtubules émanant du fuseau méiotique combiné à un faible enrichissement en actine au future pôle postérieur. Finalement, mon principal projet de thèse montre que la polarité de D. pachys est atteinte durant la méiose, au cours de laquelle le fuseau méiotique pourrait jouer un rôle par un mécanisme présent mais inhibé chez C. elegans. Chez P. pacificus, la transgénèse biolistique a été récemment utilisée avec succès. Toutefois, par manque d’un marqueur de sélection fiable, il était illusoire de poursuivre cette approche. En conclusion, les résultats de ma thèse contribuent à une meilleure compréhension de l’embryogénèse hors C. elegans. Ils soulignent l’importance de ces espèces dans l’optique d’études comparativesAsymmetric cell division is an essential process of development. The process and its regulation have been studied extensively in the Caenorhabditis elegans embryo. Asymmetric division of the single-cell embryo is a conserved process in nematode species, however, the cellular features leading up to division are surprisingly variable. During my PhD, I aimed to study these differences by using two non-C. elegans embryos: Diploscapter pachys and Pristionchus pacificus. D. pachys is the closest parthenogenetic relative to C. elegans. Since the polarity cue in C. elegans is brought by the sperm, how polarity is triggered in D. pachys remains unknown. My results show that the nucleus inhabits principally the hemisphere of the D. pachys embryo that will become the posterior pole. Moreover, in embryos where the nucleus is forced to one pole by centrifugation, it returns to its preferred pole. Although the embryo is polarized, cortical ruffling and actin cytoskeleton at both poles appear identical. Interestingly, the location of the meiotic spindle also correlates with the future posterior cell. In some oocytes, a slight actin enrichment along with unusual microtubule structures emanating from the meiotic spindle are observed at the future posterior pole. Overall, my main PhD project shows that polarity of the D. pachys embryo is attained during meiosis wherein the meiotic spindle could potentially be playing a role by a mechanism that may be present but suppressed in C. elegans. For P. pacificus, biolistic transgenesis has been shown recently successful. However, due to a lack of a stringent selection marker, the continuation of this project was unfeasible during my PhD. Altogether, the results of my PhD add to the understanding of non-C. elegans early embryogenesis and emphasizes on the importance of using these species for comparative studies
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Molnar, Kelly. „Contribution of non-muscle myosins to C. elegans embryonic elongation“. Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS091.pdf.
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La morphogenèse de l'embryon de C. elegans est caractérisée par un allongement quadruple, qui se produit sans aucune division ou intercalation cellulaire. Ce processus de changement de forme cellulaire se produit en deux étapes distinctes, dont la seconde est déclenchée par un apport mécanique des muscles. Les deux étapes nécessitent de l'actomyosine dans l'épiderme. Ce travail est une investigation de la deuxième étape, notamment l'interaction entre les muscles et l'épiderme, et le rôle précis des deux myosines non musculaires NMY-1 et NMY-2. Cette paire de moteurs moléculaires est essentielle pour l'allongement, leur inhibition à l'aide de mutants sensibles à la température ayant provoqué un arrêt immédiat, malgré l'apport mécanique continu des muscles. De plus, après l'arrêt, les myosines peuvent retrouver leur état fonctionnel et l'allongement peut reprendre. Il a également été démontré ici que des moteurs de myosine inactifs forment des agrégats dans l'épiderme. Il est probable que cette paire de myosines soit chargée de tirer les câbles d'actine circonférentiels de l'épiderme l'un vers l'autre, ce qui fournit la force nécessaire à l'allongementThe morphogenesis in the C. elegans embryo is characterized by a four-fold elongation, which occurs without any cell division or intercalation. This process of cell-shape change occurs in two distinct stages, the second of which is triggered by an initial mechanical input from the muscles. Both stages require actomyosin in the epidermis. This work is an investigation of the second stage, especially the interplay between the muscles and the epidermis, and the precise role of the two non-muscle myosins NMY-1 and NMY-2. This pair of molecular motors is essential for the late stage elongation, their inhibition using temperature sensitive mutants having been shown to cause immediate arrest, despite continued mechanical input from the muscles. Furthermore, after arrest, the myosins can return to their functional state and elongation is able to resume. Inactive myosin motors also have been shown here to form aggregates in the epidermis. It is likely that this myosin pair is responsible for pulling circumferential actin cables in the epidermis towards one another, this providing the force necessary for elongation
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Humphrey, Peter Saah. „Signal transduction mechanisms for stem cell differentation into cardiomyocytes“. Thesis, University of Hertfordshire, 2009. http://hdl.handle.net/2299/3760.
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Cardiovascular diseases are among the leading causes of death worldwide and particularly in the developed World. The search for new therapeutic approaches for improving the functions of the damaged heart is therefore a critical endeavour. Myocardial infarction, which can lead to heart failure, is associated with irreversible loss of functional cardiomyocytes. The loss of cardiomyocytes poses a major difficulty for treating the damaged heart since terminally differentiated cardiomyocytes have very limited regeneration potential. Currently, the only effective treatment for severe heart failure is heart transplantation but this option is limited by the acute shortage of donor hearts. The high incidence of heart diseases and the scarcity donor hearts underline the urgent need to find alternative therapeutic approaches for treating cardiovascular diseases. Pluripotent embryonic stem (ES) cells can differentiate into functional cardiomyocytes. Therefore the engraftment of ES cell-derived functional cardiomyocytes or cardiac progenitor cells into the damaged heart to regenerate healthy myocardial tissues may be used to treat damaged hearts. Stem cell-based therapy therefore holds a great potential as a very attractive alternative to heart transplant for treating heart failure and other cardiovascular diseases. A major obstacle to the realisation of stem cell-based therapy is the lack of donor cells and this in turn is due to the fact that, currently, the molecular mechanisms or the regulatory signal transduction mechanisms that are responsible for mediating ES cell differentiation into cardiomyocytes are not well understood. Overcoming this huge scientific challenge is absolutely necessary before the use of stem cell-derived cardiomyocytes to treat the damaged heart can become a reality. Therefore the aim of this thesis was to investigate the signal transduction pathways that are involved in the differentiation of stem cells into cardiomyocytes. The first objective was the establishment and use of cardiomyocyte differentiation models using H9c2 cells and P19 stem cells to accomplish the specific objectives of the thesis. The specific objectives of the thesis were, the investigation of the roles of (i) nitric oxide (ii) protein kinase C (PKC), (iii) p38 mitogen-activated protein kinase (p38 MAPK) (vi) phosphoinositide 3-kinase (PI3K) and (vi) nuclear factor-kappa B (NF-kB) signalling pathways in the differentiation of stem cells to cardiomyocytes and, more importantly, to identify where possible any points of convergence and potential cross-talk between pathways that may be critical for differentiation to occur. P19 cells were routinely cultured in alpha minimal essential medium (α-MEM) supplemented with 100 units/ml penicillin /100 μg/ml streptomycin and 10% foetal bovine serum (FBS). P19 cell differentiation was initiated by culturing the cells in microbiological plates in medium containing 0.8 % DMSO to form embryoid bodies (EB). This was followed by transfer of EBs to cell culture grade dishes after four days. H9c2 cells were cultured in Dulbecco’s Modified Eagle’s medium (DMEM) supplemented with 10% FBS. Differentiation was initiated by incubating the cells in medium containing 1% FBS. In both models, when drugs were employed, they were added to cells for one hour prior to initiating differentiation. Cell monolayers were monitored daily over a period of 12 or 14 days. H9c2 cells were monitored for morphological changes and P19 cells were monitored for beating cardiomyocytes. Lysates were generated in parallel for western blot analysis of changes in cardiac myosin heavy chain (MHC), ventricular myosin chain light chain 1(MLC-1v) or troponin I (cTnI) using specific monoclonal antibodies. H9c2 cells cultured in 1% serum underwent differentiation as shown by the timedependent formation of myotubes, accompanied by a parallel increase in expression of both MHC and MLC-1v. These changes were however not apparent until 4 to 6 days after growth arrest and increased with time, reaching a peak at day 12 to 14. P19 stem cells cultured in DMSO containing medium differentiated as shown by the timedependent appearance of beating cardiomyocytes and this was accompanied by the expression of cTnI. The differentiation of both P19 stem cells and H9c2 into cardiomyocytes was blocked by the PI3K inhibitor LY294002, PKC inhibitor BIM-I and the p38 MAPK inhibitor SB2035800. However when LY294002, BIM-I or SB2035800 were added after the initiation of DMSO-induced P19 stem cell differentiation, each inhibitor failed to block the cell differentiation into beating cardiomyocytes. The NF-kB activation inhibitor, CAPE, blocked H9c2 cell differentiation into cardiomyocytes. Fast nitric oxide releasing donors (SIN-1 and NOC-5) markedly delayed the onset of differentiation of H9c2 cells into cardiomyocytes while slow nitric oxide releasing donors (SNAP and NOC-18) were less effective in delaying the onset of differentiation or long term differentiation of H9c2 cells into cardiomyocytes. Akt (protein kinase B) is the key downstream target of PI3K. Our cross-talk data also showed that PKC inhibition and p38 MAPK inhibition respectively enhanced and reduced the activation of Akt, as determined by the phosphorylation of Akt at serine residue 473. In conclusion, PKC, PI3K, p38 MAPK and NF-kB are relevant for the differentiation of stem cells into cardiomyocytes. Our data also show that the PKC, PI3K and p38 MAPK signalling pathways are activated as very early events during the differentiation of stem cells into cardiomyocytes. Our data also suggest that PKC may negatively regulate Akt activation while p38 MAPK inhibition inhibits Akt activation. Our fast NO releasing donor data suggest that nitric oxide may negatively regulate H9c2 cell differentiation.
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Martin, Jacinta. „Quality control mechanisms responsible for the maintenance of genomic integrity in the female germline“. Thesis, 2019. http://hdl.handle.net/1959.13/1395720.
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Research Doctorate - Doctor of Philosophy (PhD)DNA is the genetic repository containing the necessary information for cellular viability, fate decisions and development. In the female germline, genetic integrity also underpins successful conception, embryonic development, pregnancy and the future health of the offspring. In spite of its importance, DNA remains a chemical entity prone to structural alteration. If left unresolved, these structural lesions have the potential to lead to mutation and broader-scale genomic aberrations, which may elevate the predisposition of individuals to non-communicable diseases in later life. While it is therefore likely that female germ cells possess a sophisticated suite of quality control mechanism to defend their genome, the precise nature of these defence systems is not well understood. Given this knowledge gap, the overall aim of the studies described within this thesis was to explore the endogenous DNA protection and repair machinery present in the mammalian oocyte and early embryo. In completing these studies, we have uncovered several novel protective strategies employed by the oocyte and early preimplantation embryo to safeguard their genomic integrity. These include the first evidence for a critical link between fertilisation and the synthesis of transmembrane transporter molecules belonging to the multidrug resistant protein family. Specifically, we implicate permeability glycoprotein (PGP) in increasing the bi-directional transport capacity of the zygote immediately following fertilisation. We posit that the activity of membrane bound PGP counters the influx of genotoxic agents, shielding the embryonic pronuclei from the induction of DNA damage. Excitingly, we also demonstrate that the preservation of the maternal genome, prior to fertilisation, is enhanced by an endogenous store of DNA repair proteins accumulated during oogenesis, providing the first evidence of an active DNA repair program in the post-ovulatory (MII) oocyte. Accordingly, we demonstrate a role for non-homologous end joining (NHEJ) as a repair platform for correcting damage of the maternal DNA prior to fertilisation. Having demonstrated that the oocyte and preimplantation embryo contain a sophisticated suite of defence strategies for the detection, repair or prevention of DNA damage, we hypothesized that the efficacy of these defences may be augmented by pro-survival factors. We therefore explored the capacity of C-peptide, a hormone implicated in the regulation of intracellular signalling pathways, to modulate oocyte and early embryo biology. Through this work, we observed a previously unappreciated abundance of C-peptide within the mouse ovary, oocyte and follicular fluid and uncovered a putative interaction between C-peptide and the DNA repair enzyme, breast cancer type 2 susceptibility protein (BRCA2) following oocyte activation. Collectively, these findings lend support to a novel role for C-peptide in the female germline and raise the prospect that C-peptide may exert direct physiological effects within the female reproductive system. Taken together, the findings reported in this thesis have enhanced our understanding of the maintenance of genetic stability in the female germline. Importantly, this collection of studies offers a molecular understanding of the endogenous capacity of the oocyte and preimplantation embryo to detect and subsequently respond to DNA damage and, in turn, identifies novel clinical targets to enhance oocyte competence in vitro and potentially improve assisted reproductive technologies.
Buchteile zum Thema "Embryons non-C"
1
Morriss-kay, Gillian m. „Postimplantation mammalian embryos“. In Essential Developmental Biology, 55–66. Oxford University PressOxford, 1993. http://dx.doi.org/10.1093/oso/9780199634231.003.0007.
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Abstract Techniques for culturing whole postimplantation mammalian embryos were pioneered by D.A.T. New in Cambridge (1, 2). Originally, rat embryos were cultured on plasma clots in watch glasses. Better development was found to result from the use of blood serum as a culture medium and by the use of ‘circulators’, in which continuously gassed serum passes as a constant stream through a chamber containing the embryos. The serum was obtained after allowing blood to stand and clot; embryonic development was quite good in that somites formed and the trunk elongated, but the two heart tubes often failed to fuse, and the trunk was excessively rigid, often protruding out from the curve of the yolk sac. These problems were overcome by centrifugation of the blood immediately after removal from the animal, so that the clot did not form in contact with blood cells (3). The serum is also heat-inactivated (30 min at 50 °C) to remove complement.
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Uribe, Mari-Carmen, Gabino De la Rosa-Cruz, Adriana García-Alarcón und Juan Carlos Campuzano-Caballero. „Intraovarian Gestation in Viviparous Teleosts: Unique Type of Gestation among Vertebrates“. In Veterinary Medicine and Science. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.100267.
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The intraovarian gestation, occurring in teleosts, makes this type of reproduction a such complex and unique condition among vertebrates. This type of gestation of teleosts is expressed in special morphological and physiological characteristic where occurs the viviparity and it is an essential component in the analysis of the evolutionary process of viviparity in vertebrates. In viviparous teleosts, during embryogenesis, there are not development of Müllerian ducts, which form the oviducts in the rest of vertebrates, as a result, exclusively in teleosts, there are not oviducts and the caudal region of the ovary, the gonoduct, connects the ovary to the exterior. The lack of oviducts defines that the embryos develop into the ovary, as intraovarian gestation. The ovary forms the oocytes which may develop different type of oogenesis, according with the storage of diverse amount of yolk, variation observed corresponding to the species. The viviparous gestation is characterized by the possible intimate contact between maternal and embryonic tissues, process that permits their metabolic interchanges. So, the nutrients obtained by the embryos could be deposited in the oocyte before fertilization, contained in the yolk (lecithotrophy), and may be completed during gestation by additional provisioning from maternal tissues to the embryo (matrotrophy). Then, essential requirements for viviparity in poeciliids and goodeids are characterized by: a) the diversification of oogenesis, with the deposition of different amount of yolk in the oocyte; b) the insemination, by the transfer of sperm to the female gonoduct and their transportation from the gonoduct to the germinal region of the ovary where the follicles develop; c) the intrafollicular fertilization; d) the intraovarian gestation with the development of embryos in intrafollicular gestation (as in poeciliids), or intraluminal gestation (as in goodeids); and, e) the origin of embryonic nutrition may be by lecithotrophy and matrotrophy. The focus of this revision compares the general and specific structural characteristics of the viviparity occurring into the intraovarian gestation in teleosts, defining this reproductive strategy, illustrated in this review with histological material in a poeciliid, of the species Poecilia latipinna (Lesueur, 1821) (Poeciliidae), and in a goodeid, of the species Xenotoca eiseni (Rutter, 1896) (Goodeidae).
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Tainika, Brian. „Thermal Manipulation: Embryonic Development, Hatchability, and Hatching Quality of Broiler Chicks“. In Broiler Industry [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101894.
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Here, PRISMA guidelines were utilized to systematically evaluate the publications reporting the effect of thermal manipulation during embryogenesis on incubation performance, hatchability, and hatching quality of broiler chicks. The search and selection of eligible publications was through databases web of science, PubMed, and Scopus. Publications written in English between 2015 and September 2021 were considered. It is evidenced that during TM, key considerations include duration and strength of TM besides stage of embryonic development. The moderate elevation in incubation temperature (38.5–39.5°C) intermittently (3–18 h/d) between E07 and E18 improves the chick’s thermoregulation capacity and reduces any adverse effect of TM on hatchability, and chick quality (e.g., hatch weight and chick length) compared with continuous TM. In addition, high temperature TM (38.5–39.5°C) between E7 and E18 has no significant effect on embryo mortality, hatchability, and chick quality compared to standard incubation temperature (37.8°C). TM above 39.5°C significantly increases and decreases embryo mortality and hatchability, respectively compared with standard incubation temperature. In conclusion, the results of TM studies on embryogenesis, hatchability and hatching quality of broiler chicks are still contradicting, which is a possible limitation for its commercial use.
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Plomer*, Aurora. „Towards Systemic Legal Conflict: Article 6(2)(C) of the EU Directive on Biotechnological Inventions“. In Embryonic Stem Cell Patents, 173–202. Oxford University PressOxford, 2009. http://dx.doi.org/10.1093/oso/9780199543465.003.0007.
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Abstract Patents on human embryonic stem cells could potentially be excluded under the EU Directive on Biotechnological Inventions either because they fall under the specific prohibition in Article 6(2)(c) or because they contravene the general moral exclusion clause in Article 6(1). Chapter 7 argued that the test to be applied to determine the scope of exclusion of the specific prohibition in Article 6(2)(c) is not primarily a moral, but a definitional test. By contrast, this chapter analyses the scope of application of the general moral exclusion clause in Article 6(1) whereby inventions are unpatentable if contrary to order public or morality.
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Brook, Frances A. „Procedures for deriving ES cell lines from the mouse“. In Embryonic Stem Cells, 7–40. Oxford University PressOxford, 2006. http://dx.doi.org/10.1093/oso/9780198550006.003.0002.
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Abstract Although germline-competent mouse ES (mES) cell lines are widely available, most are derived from substrains of the 129 mouse. This strain and, to a lesser extent, C57BL/6 and BALB/c have proved to be the predominant ones from which mES cell lines have been derived, not least because the testing for germline competence is a time-consuming and laborious process, and therefore efforts have been focused on deriving lines from preferred strains. There are many situations in which it is desirable to derive novel mES cell lines, and from mice other than 129 and C57BL/6. The 129 mouse is not favoured as a strain in which to develop model systems (1, 2), and so extensive backcrossing usually is required to transfer genetic modifications from a 129 background to the strain of choice. (Even then, the DNA immediately upstream and downstream of a targeted locus would remain of 129-strain origin.) In many areas of mouse genetics, much time and effort has been invested in working with a particular strain (few mutants are maintained on a 129 background), and the availability of the corresponding mES cell lines would be highly advantageous for gene targeting and in vitro differentiation studies. Furthermore, emerging techniques for the generation of mice that are entirely mES cell-derived benefit from the use of cell lines from hybrid, rather than inbred 129 or C57BL/6, mice in terms of increased efficiency of production and viability of live-born offspring (Chapter 3).
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Antonini, E., und B. Engl. „Gametes and Embryos Cryopreservation in Oncologic Patients“. In NEOPLASIA and FERTILITY, 148–57. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815050141122010010.
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Cryopreservation is a technique in which cells and tissues can be preserved at low temperature (-196 °C in liquid nitrogen). The advantage of this procedure is possibly the structural and functional preservation of gametes, embryos and male and female tissue, through the use of specific reagents, also known as cryoprotectors. In addition, cryopreservation is strongly recommended in the case of severe pathologies; for instance, oncologic patients who undergo chemo or radiotherapy treatments could be predisposed to infertility. In the past, cryopreservation was obtained using slow-freezing processes, but nowadays, thanks to several studies in this field, other approaches are taken into account, such as vitrification. Vitrification is used for gametes, avoiding several technical problems, but it’s not used for embryos and ovarian tissues, yet. As for the concerns regarding ovarian tissue, there is already evidence of successful implementation after thawing previous frozen ovarian tissue. However, this technique needs to be more deeply investigated to understand whether vitrification or slow freezing is the best approach. The advantage of freezing ovarian tissue in an oncologic patient, for example, is that no ovarian hyperstimulation is required before the tissue is harvested. Differently, for male oncologic patients, it’s enough to obtain the seminal liquid, except for pediatric patients in whom the cryopreservation of testicular tissue is recommended.
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Schnabel, Ralf. „Microscopy“. In C.elegans, 119–42. Oxford University PressOxford, 1999. http://dx.doi.org/10.1093/oso/9780199637393.003.0007.
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Abstract This chapter is designed to help you to analyse the phenotype of your favourite worm or embryo by looking through a microscope. The worm is perfectly suited to analysis by light microscopy. The dimensions of the embryo (about 55 µm) or the adult (1 mm) are just in the right range, such that the whole embryo or significant parts of the body of larvae and adults can be viewed with the highest numerical aperture and therefore with the best achievable resolution. Thus, subcellular details can be seen without losing sight of the whole animal. Although a wealth of very helpful, molecular markers of cell fate are available (e.g. antibodies, transgenic lines with green fluorescent protein (GFP) or [3 galactosidase labelled proteins, or specific probes for RNA in situ), differentiated cells show very characteristic features when viewed directly through a light microscope fitted with Nomarski (DIC) optics, so that determining which tissue or organ a cell belongs to (e.g. pharynx, gut, hypodermis, nervous system, or body wall muscle) is quite easy. The use of 4D microscopy, which allows the development of whole embryos to be documented, adds a new level to the analysis of cells since the ‘behaviour ‘ of cells can also be followed. It is an interesting question whether the expression of a single molecular marker really defines the fate of a cell unambiguously. However, if a cell looks like, migrates, and intercalates like a hypodermal cell it is very likely a hypodermal cell. Many investigators have now become interested in C. elegans because the function of their favourite molecule can be readily analysed in this nematode. It is therefore the general aim of this chapter to introduce molecular biologists to the basics of microscopy. To determine the function of the gene, at least its biological function as opposed to its ‘chemical ‘ function, one has to look through a microscope. Although this is mainly a book about methods, concepts are also very important methods and therefore a short conceptual discussion about what is required to determine the function of the gene, that is characterization of the ‘phenotype ‘ of the organism lacking a gene function, is included in the section discussing 4D microscopy.
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Tomlinson, P. B. „Embryo and seedling“. In The Structural Biology of Palms, 63–76. Oxford University PressOxford, 1990. http://dx.doi.org/10.1093/oso/9780198545729.003.0003.
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Abstract The seedling phase of development of the palm may be defined as beginning with the enlargement of the embryo some time after the fruit is mature (germination), until the exhaustion of the endosperm reserves of the seed itself, a point difficult to establish in the absence of any morphological change. An alternative would be to consider expansion of the first bladed seedling leaf (eophyll) as the end of seedling development, even though the endosperm might not be exhausted. Robertson (1983a) divided germination in Jubaeopsis into five stages, beginning with the emergence of the seedling from the seed and ending with the appearance of the first eophyll (first bladed leaf). The biochemical and structural changes which occur in the embryo and endosperm during germination are discussed later. ‘Embryology’ in the broad sense, i.e. including all phases of micro- and mega-gametophyte development as well as embryo development, is not considered in this book (but cf Robertson 1976a,b,c for a modern example).
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„Biology, Management, and Protection of North American Sturgeon“. In Biology, Management, and Protection of North American Sturgeon, herausgegeben von Xin Deng, Joel P. Van Eenennaam und Serge I. Doroshov. American Fisheries Society, 2002. http://dx.doi.org/10.47886/9781888569360.ch19.
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<em>Abstract.</em>—Gametes of green sturgeon <em>Acipenser medirostris</em> (caught in the Klamath River, California) and farm-reared white sturgeon <em>A. transmontanus</em> were obtained using hormonal induction of ovulation and spermiation. The offspring of one female in each species were reared in the laboratory, to compare their development and growth. Green and white sturgeon embryos had similar rates of development and hatched after 169 h and 176 h, respectively, at incubation temperature 15.7 ± 0.2°C. Embryos of both species exhibited similar holoblastic development and passed through 36 stages characteristic of acipenserids. Green sturgeon fertilization and hatching rates were 41.2% and 28.0%, compared with 95.4% and 82.1% for the white sturgeon. Larval survival to 45 d (metamorphosis) was 93.3% in green and 92.1% in white sturgeon. Newly hatched green sturgeon (length 13.7 ± 0.4 mm, mean ± SD) were larger and less pigmented, compared with white sturgeon. They had large ovoid yolk sacs and did not exhibit pelagic behavior that was observed in white sturgeon. The onset of exogenous feeding in green sturgeon occurred at age 10–15 d and length 24.0 ± 0.5 mm, and metamorphosis was completed at age 45 d and length 74.4 ± 5.9 mm (rearing temperature 18.5 ± 0.2°C). Weight and length of green sturgeon larvae and juveniles were considerably greater than in white sturgeon at each sampling time, but the relative growth rate and weight-length relationship were similar in both species. This suggests an effect of larger egg size and maternal yolk supply on the growth of green sturgeon. We conclude that green sturgeon differs from the white sturgeon in their reproductive strategy and, potentially, reproductive habitat.
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Dieterlen-Lie’vre, Françoise, Luc Pardanaud, Arianna Caprioli und Thierry Jaffredo. „Non-Yolk Sac Hematopoietic Stem Cells: The Avian Paradigm“. In Hematopoiesis, 201–8. Oxford University PressNew York, NY, 2001. http://dx.doi.org/10.1093/oso/9780195124507.003.0017.
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Abstract Genetic technologies in mice have revealed several mutations that affect the production of blood cells at distinct steps of ontogeny: for instance, in the yolk sac (Robb et al., 1995; Shivdasani et al., 1995), in the fetal liver (Mucenski et al., 1991), or in the bone marrow (Tsai et al., 1994; L. C. Wang et al., 1998). The cellular mechanisms underlying the temporal occurrence of these defects are not well understood, although research in this area is currently very active. The tiny mouse embryo, embedded in the uterus, is not, however, the most appropriate system for the analysis of early cell commitment, cell migration, and cell interaction.
Konferenzberichte zum Thema "Embryons non-C"
1
Young, Jonathan M., Larry A. Taber und Renato Perucchio. „Biomechanics of Early Cardiac Development: A Nonlinear Explicit FE Model of C-Looping in the Embryonic Chick Heart“. In ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19525.
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C-looping is the morphomechanical process through which the initially straight embryonic heart tube (HT) reconfigures into a doubly bent, twisted, swollen, c-shaped tube [1] between stages HH10− and HH12 [2]. According to the biomechanical hypotheses proposed by Taber [3], the ventral and rightward bending of the heart tube are intrinsic to the initially straight HT, and are caused by actin polymerization within myocardial cells. The torsion and rotation of the HT are due to a rightward oriented force generated by the elongation of the left omphalomesenteric vein (OV) and a dorsally oriented force due to tension in the splanchnopleure (SPL) [4]. In order to numerically test these biomechanical hypotheses, the standard stiffness-based nonlinear finite element formulation (standard FE) has been modified to include growth-based deformation to simulate c-looping [5]. However, due to numerical difficulties, such an approach can represent only the initial stages of c-looping and does not include SPL contact, or the merger (fusion) of the OV, which contributes to the elongation of the caudal heart tube [6]. To overcome these modeling difficulties, we propose the use of the explicit finite element formulation (explicit FE) as an alternative technique for modeling c-looping.
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Almeida, Gabriela Cristina Fonseca, und Gisela de Aragão Umbuzeiro. „Ecotoxicidade de esgoto tratado como um parâmetro operacional em ETES“. In INTERNATIONAL WORKSHOP FOR INNOVATION IN SAFE DRINKING WATER. Universidade Estadual de Campinas, 2022. http://dx.doi.org/10.20396/iwisdw.n1.2022.4795.
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Aquatic ecosystems are used as destination of urban effluents. According to Brazilian regulation, final effluents must not have the potential to cause impact on the receiving body and, to assess this impact, toxicity tests are required. The objective of this work was to evaluate the acute toxicity with Daphnia similis and chronic with Ceriodaphnia dubia of final effluents from 4 sewage plants (ETEs, named A, B, C and D) from Campinas, SP, Brazil, with different treatments’ levels. Six monthly campaigns were carried out in 2022 and samples were collected before and after chlorination. The effluents from ETE B showed acute toxicity in all campaigns, and effluents from ETE A and C showed acute toxicity in at least one campaign, but with low toxicity (EC50, 48h >50%). Chronic toxicity was detected in all effluents, except in ETE D (reuse water production station) indicating the great efficiency of the treatment of membrane bioreactors (MBR). Acute tests with fish embryos (FET) will be performed to compare the results of tests with cladocerans. The evaluation of the impact potential of the effluents will also be carried out based on the average of effluent discharges and in reference to the respective receiving bodies.
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Heo, Su-Jin, Nandan L. Nerurkar, Tristan P. Driscoll und Robert L. Mauck. „Differentiation and Dynamic Tensile Loading Alter Nuclear Mechanics and Mechanoreception in Mesenchymal Stem Cells“. In ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53432.
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Mesenchymal stem cells (MSCs) are a promising cell source for tissue engineering applications, given their ease of isolation and multi-potential differentiation capacity [1]. Passive and active mechanical signals can direct MSC lineage commitment [2], however, the subcellular machinery that translates physical cues to biologic response remains unclear. Direct deformation of the nucleus may influence differentiation by inducing mechanical reorganization of nuclear chromatin. Because the nuclei of differentiated cells are stiffer than progenitor cells [3], it is possible that such mechanoregulatory mechanisms vary with differentiation state. Lamin A/C is a filamentous protein that largely defines nuclear shape, size and stiffness [3]. Recent work suggests that Lamin A/C also regulates chromatin organization and transcriptional activity [4]. Recently, we have developed an in vitro system to direct the functional differentiation of MSCs into fibrochondrocytes, using electrospun polymeric nanofiber substrates [5]. Alignment of nanofibers directs cell alignment, allowing external forces to be applied uniformly along the long axes of cells, emulating the mechanical microenvironment experienced by embryonic progenitors during fibrous tissue morphogenesis [6]. We have noted, however, that as MSCs undergo fibrochondrogenesis, translation of scaffold deformation to nuclear deformation is attenuated [7]. From those studies, it was not clear whether this was due to changes in cellular mechanics or to accretion of extracellular matrix during differentiation. Thus the objective of the present work was to specifically identify how fibrochondrogenesis of MSCs on aligned nanofibrous scaffolds alters nuclear mechanics and mechanoreception, and further to ascertain whether mechanical stimulation alone can elicit similar mechanoregulatory changes.
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Khurana, Anil, Paramjeet Kaur, Ashok K. Chauhan, Yashpal Verma und Nupur Bansal. „Extra ovarian adult granulosa cell tumor of omentum: A report of a rare entity“. In 16th Annual International Conference RGCON. Thieme Medical and Scientific Publishers Private Ltd., 2016. http://dx.doi.org/10.1055/s-0039-1685372.
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Aims: Extra ovarian granulosa cell tumor (GCT) is extremely rare tumor, assumed to arise from the ectopic gonadal tissue along the embryonal route of the genital ridge. A case of extra ovarian granulosa cell tumor of omentum in a 69 year old female presented here. Materials and Methods: A 69 years old postmenopausal, hypertensive female presented with complaints of pain in right lumber and iliac region of one month duration. Pain was off and on and intermittent. The patient had a history of hysterectomy 12 years ago for fibroid uterus. Results: Ultrasound examination of abdomen showed a hypoechoic lesion of size 78.1 mm x 57.3 mm in right iliac fossa with mild thickening of surrounding omentum. Another hypoechoic lesion of size 36.7 mm x 22.9 mm was seen in retroperitoneal region in supero-medial aspect of right kidney. CECT abdomen showed heterogeneously enhanced nodular lesion of size 6.6 x 6.8 cm in right lumbar region, mild thickening of surrounded omentum also seen however there was no evidence of infiltration to bowel loop seen. Uterus was not visualized. PET CT whole body revealed mildly metabolically active enlarged nodes in the bilateral level ib an ii, metabolically active large lobulated heterogeneously enhancing soft tissue density lesion in right lumbar region with non enhancing areas of necrosis. The lesion is closely abutting the anterior abdominal wall musculature antero laterally and small bowel loop medially surrounding mesenty shows increased vascularity and haziness. Colonoscopy findings were normal. Trucut biopsy of mass right lumbar region was positive for malignancy likely Round cell Sarcoma. A provisional diagnosis of retroperitoneal sarcoma of right lumbar region was made. She underwent exploratory laparotomy with excision of tumor. As per Operative findings there was approximately 8 x 7 cm, firm, omental mass present right to midline, arising from under surface of greater omentum. Ovaries were normal. Gross examination of omental mass showed nodular mass measuring 8 x 5 x 6 cm. External surface was multinodular and cut surface was grey brown to grey yellow with solid cystic areas and areas of necrosis. Microscopic examination of specimen showed Extraovarian Adult granulosa cell tumor/metastasis from occult granulose cell tumor. On IHC Vimentin, CK, SMA, Inhibin were positive, Ki67:15%, ER/PR were also positive and are negative for calretinin, thromobomodulin. Extensive necrosis was seen. After that she underwent rexploration and total omenectomy. HPE showed fat necrosis in omentum. All investigation showed no evidence of tumor in ovaries and at any other primary site then the patient finally diagnosed as having Granulosa cell tumor involving only omentum post op stage III C. Then patient was given six courses of chemotherapy with Inj Paclitaxel and Inj Carboplatin three weekly. Now patient is on regular follow up and disease free. Conclusion: Extra ovarian adult granulosa cell tumor of omentum is rare tumor. Multimodal treatment approaches including surgery, multi-agent chemotherapy may provide a survival benefit for patients.
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Morinaga, T., Y. Itagaki, A. Suzuki, H. Yasuda und K. Higashio. „PURIFICATION AND CHARACTERIZATION OF TISSUE PLASMINOGEN ACTIVATOR PRODUCED BY IMR-90 CELLS“. In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644393.
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Tissue plasminogen activator ( t-PA ) produced by IMR-90 ( human embryonic fibroblast ) cells cultured in the serum-free medium ( DMEM ) containing 1% proteos^e peptone and 1.6 - 3.6mM CaCl2 was purified by the procedure consisted of ultrafiltration, immunoadsorpt ion chromatography, HPLC and lysine-Sepharose chromatography. The yield of t-PA from the culture broth was approximately 47%. The purified t-PA migrated as a single band on SDS-polyacrylamide gels. The molecular weight of the t-PA was estimated to be 66,000 by SDS-polyacrylamide gel electrophoresis and 69,000 by gel filtration method. Purified t-PA had a specific activity of 36 × 104 IU/mg protein by fiblin plate method or 54 - 56 X 104 IU/mg protein by clot lysis method using t-PA obtained from WHO as a standard. The amino acid composition of fibroblast t-PA was very similar to those of melanoma t-PA and uterine t-PA. Isoelectric point of fibroblast t-PA ranged from 5-7 to 8.2. The t-PA had twice as much affinity for fiblin as did high molecular weight urokinase ( UK ). Both t-PA and UK had optimum temperature at 41°C and optimum pH between 8.0 - 9.0. The polyclonal and monoclonal antibodies raised against t-PA quenched t-PA activity but had no effect on UK activity. The inhibitors of serine proteases, difluorophos-phate and gabexate mesilate, strongly inhibited the activities of fibroblast t-PA and UK. The nucleotide sequence analysis of the t-PA cDNA isolated from the cDNA library prepared from IMR-90 mRNA revealed the nucleotide changes at two positions in the coding region as compared to that of melanoma t-PA cDNA. Neither of the changes replaced the coded amino acid. The N-terminal amino acid of fibroblast t-PA was determined to be valine, indicatig the structural similarity of fibroblast t-PA to uterine t-PA.
Berichte der Organisationen zum Thema "Embryons non-C"
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Browdy, Craig, und Esther Lubzens. Cryopreservation of Penaeid Shrimp Embryos: Development of a Germplasm Cryo-Bank for Preservation of High Health and Genetically Improved Stocks. United States Department of Agriculture, August 2002. http://dx.doi.org/10.32747/2002.7695849.bard.
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The objectives of the project were to develop a successful protocol for cryopreservation of penaeid germ plasm in order to preserve a pathogen-free broodstock nucleus for commercial exploitation of marine shrimp in aquaculture. The critical parameters to be characterized in the project were: 1. Determination of chill sensitivity and chill tolerant embryonic stages, including a full description and time course study of embryonic developmental stages. 2. Development of protocols for loading and removal of cryoprotectant agents (CPAs) from embryos; determination of optimal concentrations and duration of loading. 3. Characterization of the toxicity of the selected CP As and 4. Establishing optimal cooling and thawing procedures. Studies were performed on two penaeid species: Litopenaeus vannamei (in the USA) and P. semisulcatus (in Israel). The effect of incubation temperature on embryonic development rate and hatching success was studied in L. vannamei, showing that spawns maybe maintained at temperatures ranging from 24°C to 30°C, without compromising hatchability. Embryonic development extends from 12 hr to 19 hr at 30°C and 24°C, respectively. Studies showed that advanced embryonic developmental stages were chill tolerant in the two studied species, but P. semisulcatus could better endure lower temperatures than L. vannamei. A large number of experiments were performed to determine the optimal CP As, their concentration and duration of loading. Permeating (e.g. glycerol, methanol, DMSO, 1,2- propanediol, ethylene glycol, glucose) and non-permeating CPAs (sucrose, PVP, polyethylene glycol) were tested and several combinations of permeating and non-permeating CP As, on fertilized eggs (embryos), nauplii and protozoeae. In general, nauplii tolerated higher CPA concentrations than eggs and nauplii were also more permeable to radiolabeled methanol. Chlorine treatment intended to remove the chitinous envelop from eggs, did not increase dramatically the permeation of radiolabled methanol into eggs. Cooling eggs, nauplii or protozoeae to cryogenic temperatures, by either vitrification or slow cooling protocols, did not result in full survival of thawed samples, despite exhaustive attempts testing various protocols and CP As. Results seemed more encouraging in freezing of nauplii in comparison to eggs or protozoeae. Successful preliminary results in cryopreservation of spermatozoa of P. vannamei, will facilitate preservation of genetic specific to some extent.
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Halevy, Orna, Zipora Yablonka-Reuveni und Israel Rozenboim. Enhancement of meat production by monochromatic light stimuli during embryogenesis: effect on muscle development and post-hatch growth. United States Department of Agriculture, Juni 2004. http://dx.doi.org/10.32747/2004.7586471.bard.
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The original objectives were: A. To determine the critical embryonic age for monochromatic green light stimulation. B. To follow the ontogeny of embryos exposed to monochromatic green light vs. darkness. C. To investigate the effects of monochromatic green light illumination on myoblast and fiber development in the embryo. D. To investigate the stimulatory effect of light combinations during embryo and post-hatch periods on growth and meat production. E. To evaluate the direct effect of monochromatic green light on cultured embryonic and adult myoblasts. The overall purpose of this study was to investigate the effect of monochromatic light stimuli during incubation period of broilers on muscle development and satellite cell myogenesis. Based on previous studies (Halevy et al., 1998; Rozenboim et al., 1999) that demonstrated the positive effects of green-light illumination on body and muscle growth, we hypothesized that monochromatic light illumination accelerates embryo and muscle development and subsequently enhances muscle growth and meat production. Thus, further decreases management costs. Under the cooperation of the laboratories at the Hebrew University of Jerusalem and University of Washington we have conducted the following: 1. We have established the critical stage for exposure to green monochromatic light which has the maximal effect on body and muscle growth (Objective A). We report that embryonic day 5 is optimal for starting illumination. The optimal regime of lighting that will eliminate possible heat effects was evaluated by monitoring egg core temperature at various illumination periods. We found that intermitted lighting (15 min. on; 15 min. off) is optimal to avoid heat effects. 2. We have evaluated in detail gross changes in embryo development profile associated to green light stimuli vs. darkness. In addition, we have investigated the stimulatory effect of light combinations during embryo and post-hatch periods on body and muscle growth (Objective B,D). 3. We have studied the expression profile of muscle regulatory proteins during chicken muscle cell differentiation in cultures using newly developed antibodies. This study paved the way for analyzing the expression of these proteins in our photo stimulation experiments (Objective C). 4. We have studied the pattern ofPax7 expression during myogenesis in the posthatch chicken. Experimental chick pectoralis muscles as well adult myoblast cultures were used in this study and the results led us to propose a novel model for satellite cell differentiation and renewal. 5. The effects of monochromatic green light illumination during embryogenesis have been studied. These studies focused on fetal myoblast and satellite cell proliferation and differentiation at pre- and posthatch periods and on the effects on the expression of muscle regulatory proteins which are involved in these processes. In addition, we have analyzed the effect of photo stimulation in the embryo on myofiber development at early posthatch (Objective C). 6. In follow the reviewers' comments we have not conducted Objective E. The information gathered from these studies is of utmost importance both, for understanding the molecular basis of muscle development in the posthatch chicks and for applied approach for future broiler management. Therefore, the information could be beneficial to agriculture in the short term on the one hand and to future studies on chick muscle development in the embryo and posthatch on the other hand.
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Adelberg, Jeff, Halina Skorupska, Bill Rhodes, Yigal Cohen und Rafael Perl-Treves. Interploid Hybridization of Cucumis melo and C. metuliferus. United States Department of Agriculture, Dezember 1999. http://dx.doi.org/10.32747/1999.7580673.bard.
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The long-term motivation for this research is to transfer useful traits from a broad based gene pool of wild species into the narrow base of a cultivated crop in Cucumis. Our primary focus was to use polyploid prior to fertilization as a tool to overcome fertility barriers in the cross between C. melo and C. metuliferus. In conducting this research, we explored all combinations of tetraploid and diploid parents, in reciprocal combinations. Pollinations were made in both the field and greenhouse, using emasculated flowers, moneocious females, and open pollination by insect vectors, with morphological selection criteria. After observations of thousands of ovaries, we still have no definitive proof that this hybridization yielded viable embryos. The most promising results came from using tetraploid C. metuliferus, as the maternal parent in the interspecific hybridization, that set fruit were seeds contained small embryos that did not germinate. To obtain fruit set, it was important to rear plants in a cooler sunny greenhouse, as would be found in late winter/early spring. A second interspecific hybrid between wild and cultivated Cucumis, C. hystrix x C. sativus, yielded fertile progeny for the first time, while concomitantly working toward our primary goal. Two distinct treatments were necessary; 1) special plant husbandry was necessary to have the wild species produce fruit in cultivation, and 2) embryo rescue followed by chromosome doubling in vitro was required for fertility restoration. Backcrosses to crop species and resistance to nematodes are compelling areas for further work.
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Yahav, Shlomo, John Brake und Orna Halevy. Pre-natal Epigenetic Adaptation to Improve Thermotolerance Acquisition and Performance of Fast-growing Meat-type Chickens. United States Department of Agriculture, September 2009. http://dx.doi.org/10.32747/2009.7592120.bard.
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: The necessity to improve broiler thermotolerance and performance led to the following hypothesis: (a) thethermoregulatory-response threshold for heat production can be altered by thermal manipulation (TM) during incubation so as to improve the acquisition of thermotolerance in the post-hatch broiler;and (b) TM during embryogenesis will improve myoblast proliferation during the embryonic and post-hatch periods with subsequent enhanced muscle growth and meat production. The original objectives of this study were as follow: 1. to assess the timing, temperature, duration, and turning frequency required for optimal TM during embryogenesis; 2. to evaluate the effect of TM during embryogenesis on thermoregulation (heat production and heat dissipation) during four phases: (1) embryogenesis, (2) at hatch, (3) during growth, and (4) during heat challenge near marketing age; 3. to investigate the stimulatory effect of thermotolerance on hormones that regulate thermogenesis and stress (T₄, T₃, corticosterone, glucagon); 4. to determine the effect of TM on performance (BW gain, feed intake, feed efficiency, carcass yield, breast muscle yield) of broiler chickens; and 5. to study the effect of TM during embryogenesis on skeletal muscle growth, including myoblast proliferation and fiber development, in the embryo and post-hatch chicks.This study has achieved all the original objectives. Only the plasma glucagon concentration (objective 3) was not measured as a result of technical obstacles. Background to the topic: Rapid growth rate has presented broiler chickens with seriousdifficulties when called upon to efficiently thermoregulate in hot environmental conditions. Being homeotherms, birds are able to maintain their body temperature (Tb) within a narrow range. An increase in Tb above the regulated range, as a result of exposure to environmental conditions and/or excessive metabolic heat production that often characterize broiler chickens, may lead to a potentially lethal cascade of irreversible thermoregulatory events. Exposure to temperature fluctuations during the perinatal period has been shown to lead to epigenetic temperature adaptation. The mechanism for this adaptation was based on the assumption that environmental factors, especially ambient temperature, have a strong influence on the determination of the “set-point” for physiological control systems during “critical developmental phases.” In order to sustain or even improve broiler performance, TM during the period of embryogenesis when satellite cell population normally expand should increase absolute pectoralis muscle weight in broilers post-hatch. Major conclusions: Intermittent TM (39.5°C for 12 h/day) during embryogenesis when the thyroid and adrenal axis was developing and maturing (E7 to E16 inclusive) had a long lasting thermoregulatory effect that improved thermotolerance of broiler chickens exposed to acute thermal stress at market age by lowering their functional Tb set point, thus lowering metabolic rate at hatch, improving sensible heat loss, and significantly decreasing the level of stress. Increased machine ventilation rate was required during TM so as to supply the oxygen required for the periods of increased embryonic development. Enhancing embryonic development was found to be accomplished by a combination of pre-incubation heating of embryos for 12 h at 30°C, followed by increasing incubation temperature to 38°C during the first 3 days of incubation. It was further facilitated by increasing turning frequency of the eggs to 48 or 96 times daily. TM during critical phases of muscle development in the late-term chick embryo (E16 to E18) for 3 or 6 hours (39.5°C) had an immediate stimulatory effect on myoblast proliferation that lasted for up to two weeks post-hatch; this was followed by increased hypertrophy at later ages. The various incubation temperatures and TM durations focused on the fine-tuning of muscle development and growth processes during late-term embryogenesis as well as in post-hatch chickens.
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Shani, Moshe, und C. P. Emerson. Genetic Manipulation of the Adipose Tissue via Transgenesis. United States Department of Agriculture, April 1995. http://dx.doi.org/10.32747/1995.7604929.bard.
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The long term goal of this study was to reduce caloric and fat content of beef and other red meats by means of genetic modification of the animal such that fat would not be accumulated. This was attempted by introducing into the germ line myogenic regulatory genes that would convert fat tissue to skeletal muscle. We first determined the consequences of ectopic expression of the myogenic regulatory gene MyoD1. It was found that deregulation of MyoD1 did not result in ectopic skeletal muscle formation but rather led to embryonic lethalities, probably due to its role in the control of the cell cycle. This indicated that MyoD1 should be placed under stringent control to allow survival. Embryonic lethalities were also observed when the regulatory elements of the adipose-specific gene adipsin directed the expression of MyoD1 or myogenin cDNAs, suggesting that these sequences are probably not strong enough to confer tissue specificity. To determine the specificity of the control elements of another fat specific gene (adipocyte protein 2-aP2), we fused them to the bacterial b-galactosidase reporter gene and established stable transgenic strains. The expression of the reporter gene in none of the strains was adipose specific. Each strain displayed a unique pattern of expression in various cell lineages. Most exciting results were obtained in a transgenic strain in which cells migrating from the ventro-lateral edge of the dermomyotome of developing somites to populate the limb buds with myoblasts were specifically stained for lacZ. Since the control sequences of the adipsin or aP2 genes did not confer fat specificity in transgenic mice we have taken both molecular and genetic approaches as an initial effort to identify genes important in the conversion of a multipotential cell such as C3H10T1/2 cell to adipoblast. Several novel adipocyte cell lines have been established that differ in the expression of transcription factors of the C/EBP family known to be markers for adipocyte differentiation. These studies revealed that one of the genetic programming changes which occur during 10T1/2 conversion from multipotential cell to a committed adipoblast is the ability to linduce C/EBPa gene expression. It is expected that further analysis of this gene would identify elements which regulate this lineage-specific expression. Such elements might be good candidates in future attempts to convert adipoblasts to skeletal muscle cells in vivo.
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Schat, Karel Antoni, Irit Davidson und Dan Heller. Chicken infectious anemia virus: immunosuppression, transmission and impact on other diseases. United States Department of Agriculture, 2008. http://dx.doi.org/10.32747/2008.7695591.bard.
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1. Original Objectives. The original broad objectives of the grant were to determine A) the impact of CAV on the generation of cytotoxic T lymphocytes (CTL) to reticuloendotheliosis virus (REV) (CU), B). the interactions between chicken anemia virus (CAV) and Marek’s disease virus (MDV) with an emphasis on horizontal spread of CAV through feathers (KVI), and C) the impact of CAV infection on Salmonella typhimurium (STM) (HUJI). During the third year and the one year no cost extension the CU group included some work on the development of an antigen-antibody complex vaccine for CAV, which was partially funded by the US Poultry and Egg Association. 2. Background to the topic. CAV is a major pathogen causing clinical disease if maternal antibody-free chickens are infected vertically or horizontally between 1 and 14 days of age. Infection after 3 weeks of age when maternal antibodies are not longer present can cause severe subclinical immunosuppression affecting CTL and cytokine expression. The subclinical immunosuppression can aggravate many diseases including Marek’s disease (MD) and several bacterial infections. 3. Major conclusions and achievements. The overall project contributed in the following ways to the knowledge about CAV infection in poultry. As expected CAV infections occur frequently in Israel causing problems to the industry. To control subclinical infections vaccination may be needed and our work indicates that the development of an antigen-antibody complex vaccine is feasible. It was previously known that CAV can spread vertically and horizontally, but the exact routes of the latter had not been confirmed. Our results clearly show that CAV can be shed into the environment through feathers. A potential interaction between CAV and MD virus (MDV) in the feathers was noted which may interfere with MDV replication. It was also learned that inoculation of 7-day-old embryos causes growth retardation and lesions. The potential of CAV to cause immunosuppression was further examined using CTL responses to REV. CTL were obtained from chickens between 36 and 44 days of age with REV and CAV given at different time points. In contrast to our earlier studies, in these experiments we were unable to detect a direct impact of CAV on REV-specific CTL, perhaps because the CTL were obtained from older birds. Inoculation of CAV at one day of age decreased the IgG antibody responses to inactivated STM administered at 10 days of age. 4. Scientific and Agricultural Implications The impact of the research was especially important for the poultry industry in Israel. The producers have been educated on the importance of the disease through the many presentations. It is now well known to the stakeholders that CAV can aggravate other diseases, decrease productivity and profitability. As a consequence they monitor the antibody status of the breeders so that the maternal antibody status of the broilers is known. Also vaccination of breeder flock that remain antibody negative may become feasible further reducing the negative impact of CAV infection. Vaccination may become more important because improved biosecurity of the breeder flocks to prevent avian influenza and Salmonella may delay the onset of seroconversion for CAV by natural exposure resulting in CAV susceptible broilers lacking maternal antibodies. Scientifically, the research added important information on the horizontal spread of CAV through feathers, the interactions with Salmonella typhimurium and the demonstration that antigen-antibody complex vaccines may provide protective immunity.
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Spencer, Thomas E., Elisha Gootwine, Arieh Gertler und Fuller W. Bazer. Placental lactogen enhances production efficiency in sheep. United States Department of Agriculture, Dezember 2005. http://dx.doi.org/10.32747/2005.7586543.bard.
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The key objectives of this BARD project were to: (1) study long-term effects of immunization of prepubertal ewes against recombinant ovine placental lactogen (roPL) on subsequent birth weights of their lambs and their milk production; (2) optimize the anti-roPL immunization protocol using adjuvant preparations acceptable to producers and regulatory agencies; and (3) determine the physiological mechanism(s) whereby immunization against oPL increases fetal growth and development and mammogenesis. These objectives were based on key findings from a previous BARD project that: (a) immunization of ewes against roPL increased lamb birth weight and ewe milk production during lactation; (b) roPL and recombinant ovine growth hormone (roGH) increased the proliferation and differentiated function of endometrial glands that, in turn, would enhance uterine secretions necessary for fetal and placental growth; and (c) exogenous roPL and roGH stimulated mammogenesis and milk production during lactation. The BARD projects address central problems in sheep production, including reproductive failure due to embryonic/fetal mortality, low birth weight of lambs especially in prolific breeds, and reduced milk yields which affect neonatal survival. The sheep placenta secretes both lactogenic (oPL) and somatogenic (oGH) hormones. The receptors for those hormones are present in the fetus and placenta as well as maternal uterus, and mammary gland. Our research has focused on determining the biological role of these placental hormones in development and differentiation of the uterus during gestation and the mammary gland during pregnancy and lactation. Studies conducted in the current BARD project indicated that the effects of anti-roPL immunization were variable in ewes and that commercially available and widely acceptable adjuvant preparations were not effective to produce high anti-roPL titers in pre-pubertal ewes. In the non-prolific Rambouillet ewe in Texas and in the Awassi and the Assaf in Israel, anti-roPL immunization increased lamb birth weight; however, the magnitude of this effect and the inherent variability precluded our ability to determine the physiological mechanism of how the immunization increases fetal growth. Collectively, our findings suggest that anti-roPL immunization is not currently feasible as an easy and efficacious tool for the producer to increase flock reproductive and production efficiency. The variability in response of individual ewes to anti-roPL immunization likely includes modifying the recombinant hormone and the type of adjuvant used for the immunization. In particular, the oPL may need to be modified to ensure maximum antigenicity in a broad range of breed types. Nonetheless, the investigators continue to collaborate on identifying fundamental mechanisms that can be improved by genetics or management to enhance the efficiency of uteroplacental function and, in turn, fetal growth and development. High prolificacy is a desirable trait in intensive sheep production systems. One of the main limitations of using prolific breeds of sheep is that increased litter size is associated with low birth weights and increased mortality of lambs. Further, low birth weight is associated with an increased propensity for adult diseases and decreased production efficiency. Indeed, our recent studies find that the birth weights of lambs born in large litters can be improved by both genetics and management. Future cooperative research will continue to focus on reproductive efficiency of sheep that have broader implications for improving production efficiency in all types of ruminant livestock.
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Funkenstein, Bruria, und Shaojun (Jim) Du. Interactions Between the GH-IGF axis and Myostatin in Regulating Muscle Growth in Sparus aurata. United States Department of Agriculture, März 2009. http://dx.doi.org/10.32747/2009.7696530.bard.
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Growth rate of cultured fish from hatching to commercial size is a major factor in the success of aquaculture. The normal stimulus for muscle growth in growing fish is not well understood and understanding the regulation of muscle growth in fish is of particular importance for aquaculture. Fish meat constitutes mostly of skeletal muscles and provides high value proteins in most people's diet. Unlike mammals, fish continue to grow throughout their lives, although the size fish attain, as adults, is species specific. Evidence indicates that muscle growth is regulated positively and negatively by a variety of growth and transcription factors that control both muscle cell proliferation and differentiation. In particular, growth hormone (GH), fibroblast growth factors (FGFs), insulin-like growth factors (IGFs) and transforming growth factor-13 (TGF-13) play critical roles in myogenesis during animal growth. An important advance in our understanding of muscle growth was provided by the recent discovery of the crucial functions of myostatin (MSTN) in controlling muscle growth. MSTN is a member of the TGF-13 superfamily and functions as a negative regulator of skeletal muscle growth in mammals. Studies in mammals also provided evidence for possible interactions between GH, IGFs, MSTN and the musclespecific transcription factor My oD with regards to muscle development and growth. The goal of our project was to try to clarify the role of MSTNs in Sparus aurata muscle growth and in particular determine the possible interaction between the GH-IGFaxis and MSTN in regulating muscle growth in fish. The steps to achieve this goal included: i) Determining possible relationship between changes in the expression of growth-related genes, MSTN and MyoD in muscle from slow and fast growing sea bream progeny of full-sib families and that of growth rate; ii) Testing the possible effect of over-expressing GH, IGF-I and IGF-Il on the expression of MSTN and MyoD in skeletal muscle both in vivo and in vitro; iii) Studying the regulation of the two S. aurata MSTN promoters and investigating the possible role of MyoD in this regulation. The major findings of our research can be summarized as follows: 1) Two MSTN promoters (saMSTN-1 and saMSTN-2) were isolated and characterized from S. aurata and were found to direct reporter gene activity in A204 cells. Studies were initiated to decipher the regulation of fish MSTN expression in vitro using the cloned promoters; 2) The gene coding for saMSTN-2 was cloned. Both the promoter and the first intron were found to be polymorphic. The first intron zygosity appears to be associated with growth rate; 3) Full length cDNA coding for S. aurata growth differentiation factor-l I (GDF-II), a closely related growth factor to MSTN, was cloned from S. aurata brain, and the mature peptide (C-terminal) was found to be highly conserved throughout evolution. GDF-II transcript was detected by RT -PCR analysis throughout development in S. aurata embryos and larvae, suggesting that this mRNA is the product of the embryonic genome. Transcripts for GDF-Il were detected by RT-PCR in brain, eye and spleen with highest level found in brain; 4) A novel member of the TGF-Bsuperfamily was partially cloned from S. aurata. It is highly homologous to an unidentified protein (TGF-B-like) from Tetraodon nigroviridisand is expressed in various tissues, including muscle; 5) Recombinant S. aurata GH was produced in bacteria, refolded and purified and was used in in vitro and in vivo experiments. Generally, the results of gene expression in response to GH administration in vivo depended on the nutritional state (starvation or feeding) and the time at which the fish were sacrificed after GH administration. In vitro, recombinantsaGH activated signal transduction in two fish cell lines: RTHI49 and SAFI; 6) A fibroblastic-like cell line from S. aurata (SAF-I) was characterized for its gene expression and was found to be a suitable experimental system for studies on GH-IGF and MSTN interactions; 7) The gene of the muscle-specific transcription factor Myogenin was cloned from S. aurata, its expression and promoter activity were characterized; 8) Three genes important to myofibrillogenesis were cloned from zebrafish: SmyDl, Hsp90al and skNAC. Our data suggests the existence of an interaction between the GH-IGFaxis and MSTN. This project yielded a great number of experimental tools, both DNA constructs and in vitro systems that will enable further studies on the regulation of MSTN expression and on the interactions between members of the GHIGFaxis and MSTN in regulating muscle growth in S. aurata.