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41.
Bovine ovarian stem cells differentiate into germ cells and oocyte‐like structures after culture in vitro 
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下载免费PDF全文 GB de Souza JJN Costa EV da Cunha JRS Passos RP Ribeiro MVA Saraiva R van den Hurk JRV Silva 《Reproduction in domestic animals》2017,52(2):243-250
Stem cells have been isolated from ovaries, and their ability to differentiate into oocytes in vitro has been demonstrated for mice and human, but not for bovine species. The aims of this study were to isolate germline stem cells from bovine ovaries and to evaluate the effects of bone morphogenetic proteins (BMPs) 2 and 4, and follicular fluid on the differentiation of these stem cells into oocyte‐like structures. The ovarian stem cells were isolated and cultured in α‐MEM+ supplemented with BMP2, BMP4 or follicular fluid. On days 0 and 14, cells were evaluated for their morphological appearance, viability, expression of alkaline phosphatase and for markers of germ cell formation (VASA and DAZL) and oocyte development (GDF9, ZPA and SCP3) by qPCR. Levels of mRNA were analysed using ANOVA and Bonferroni test (p < .05). The results showed that at day 0, ovarian stem cells expressed specific markers of pluripotency (OCT4, SOX). In addition, these cells were positive for alkaline phosphatase, which is a marker commonly used to identify primordial germ cells (PGCs). After the period of differentiation, cells had morphological features that resemble PGCs and oocyte‐like cells (OLCs). An increase, ranging from five to 14 times, in the expression of VASA was observed in cells cultured in medium supplemented with BMPs and follicular fluid, while the increase in DAZL expression ranged from four to six times. In addition, OLCs had an increase in expression of mRNAs for GDF9, ZPA and SCP3 that ranged from two to eight times. In conclusion, OLCs can be differentiated in vitro from ovarian stem cells and BMPs and follicular fluid are effective in stimulating the expression of mRNAs for germ cell and oocyte markers. 相似文献
42.
RP Cervera MA Silvestre N Martí E García‐Mengual R Moreno M Stojkovic 《Reproduction in domestic animals》2010,45(5):e12-e20
Among the factors that affect the efficiency of somatic cell nuclear transfer (SCNT) in pigs, the activation protocol is the most variable among the current SCNT procedures. The aim of this study is focused on defining an efficient activation treatment of porcine oocytes. In Experiment 1, we studied the effects of nine different oocyte activation procedures (including chemical‐ and electrical‐based treatments) on parthenogenetic embryo development. In Experiment 2, we studied the effect of the more efficient activation procedures on the gene expression profile of Oct4 and Igf2r in parthenogenetic blastocysts. In conclusion, ionomycin as a first calcium stimulus is not able to activate porcine oocytes efficiently in comparison with electric procedures. Electrical treatments with 6‐DMAP significantly increased the level of Oct4 expression, whereas the single and double pulse treatments alone maintained the same profile as the IVF group. 相似文献
43.
Although ordinary chondrite (OC) meteorites dominate observed falls, the identification of near-Earth and main-belt asteroid sources has remained elusive. Telescopic measurements of 35 near-Earth asteroids ( approximately3 kilometers in diameter) revealed six that have visible wavelength spectra similar to laboratory spectra of OC meteorites. Near-Earth asteroids were found to have spectral properties that span the range between the previously separated domains of OC meteorites and the most common (S class) asteroids, suggesting a link. This range of spectral properties could arise through a diversity of mineralogies and regolith particle sizes, as well as through a time-dependent surface weathering process. 相似文献
44.
R Agarwal KVH Sastry V Tripathi R Singh R Saxena J Mohan RP Singh 《Reproduction in domestic animals》2013,48(2):278-283
In the present study, the expression profile of luteinizing hormone receptor (LHR) was investigated in the ovary, magnum and uterus and in hierarchcal follicles (F‐1, F‐2, F‐3 and F‐4) of hens subjected to moulting to establish their involvement in moulting and presence in non‐gonadal tissues. Fifty‐two layers (72 weeks) were subjected to moult for a period of 14 days. Four birds were sacrificed each time on 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12 and 14 days of moulting, and samples (ovary, magnum, uterus and hierarchal follicles) were collected aseptically for the quantitative study by real‐time polymerase chain reaction. The ovary, isthmus, uterus and magnum weight reduced significantly during induced moulting. From the 4 DOM, this reduction was drastic and reached approximately 80% of original weight in the case of ovary, isthmus and magnum and approximately 65% of original weight in the case of uterus on 14 DOM. Ovarian yellow follicles decreased gradually from 1 DOM to 4 DOM, after that no normal yellow follicle was observed in moulted bird. The number of atretic follicles increased gradually during the course of induced moulting, reaching the peak at 5 DOM. The LHR mRNA was detected in non‐gonadal tissues like magnum and uterus. The LHR expression was significantly (p < 0.05) down regulated in ovary, magnum and uterus throughout the treatment. These results indicated that LHR may have a role in reproductive tissue regression during moulting. 相似文献
45.
F Hill PB Stark RT Stebbins ER Anderson HM Antia TM Brown TL Duvall DA Haber JW Harvey DH Hathaway R Howe RP Hubbard HP Jones JR Kennedy SG Korzennik AG Kosovichev JW Leibacher KG Libbrecht JA Pintar EJ Rhodes J Schou MJ Thompson S Tomczyk CG Toner R Toussaint WE Williams 《Science (New York, N.Y.)》1996,272(5266):1292-1296
The Global Oscillation Network Group (GONG) project estimates the frequencies, amplitudes, and linewidths of more than 250,000 acoustic resonances of the sun from data sets lasting 36 days. The frequency resolution of a single data set is 0.321 microhertz. For frequencies averaged over the azimuthal order m, the median formal error is 0.044 microhertz, and the associated median fractional error is 1.6 x 10(-5). For a 3-year data set, the fractional error is expected to be 3 x 10(-6). The GONG m-averaged frequency measurements differ from other helioseismic data sets by 0.03 to 0.08 microhertz. The differences arise from a combination of systematic errors, random errors, and possible changes in solar structure. 相似文献
46.
The stable carbon isotope (delta13C) compositions of individual fatty acid components of remnant fats preserved in archaeological pottery vessels show that dairying was a component of archaeological economies. Characteristic delta13C values arise from biases in the biosynthetic origins of the C18:0 fatty acids in milk and adipose fat. Milk and adipose fat from animals raised on similar pastures and fodders have distinct isotopic signatures. 相似文献