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A Najafi MH Najafi Z Zanganeh M Sharafi F Martinez‐Pastor H Adeldust 《Reproduction in domestic animals》2014,49(6):934-940
A soybean lecithin‐based extender supplemented with hyaluronic acid (HA) was assayed for effectiveness to improve the quality of frozen–thawed ram semen. HA has not been tested yet in an extender containing soybean lecithin for freezing ram semen. Thus, the aim of this study was to analyse the effects of soybean lecithin at 1% or 1.5% along with HA at 0, 0.5 and 1 mg ml‐1 in a Tris‐based extender on the motion characteristics, membrane integrity (HOST), viability, GSH peroxidase (GSH‐PX) activity, lipid peroxidation and acrosomal status after freezing–thawing. Semen was collected from four Mehraban rams during the breeding season and frozen in the six lecithin×HA extenders. The extender containing 1.5% lecithin supplemented with no HA yielded higher total motility (52.5%±1.6), viability (55.8%±1.6) and membrane integrity (44.5%±1.7), but the effects of the lecithin concentration did not reach signification. Linearity‐related parameters, ALH, BCF, lipid peroxidation, GSH‐PX activity, morphology and acrosomal status were not affected by the extender composition. In general, adding HA significantly decreased sperm velocity (1 mg ml‐1 HA), total motility (only with 1.5% lecithin), viability (1 mg ml‐1 HA for 1% lecithin; both concentrations for 1.5% lecithin) and membrane integrity. In conclusion, adding HA to the freezing extender supplemented with soybean lecithin failed to improve quality‐related variables in ram semen. Increasing the lecithin content could have a positive effect, but further studies are needed. 相似文献
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JI Yun HJ Park MH Park MS Kim JH Choi E Lee SP Gong JM Lim ST Lee 《Reproduction in domestic animals》2014,49(5):705-710
Recently, isolation and in vitro culture of putative spermatogonial stem cells (SSCs) in the domestic cat have been conducted. However, the cellular niche conditions that facilitate the establishment and long‐term maintenance of feline SSCs (FSSCs) have not been described. Therefore, we investigated the type of feeder cells used to stimulate colony formation and growth of FSSCs among the various factors in the FSSC niche. Spermatogonial stem cells isolated from feline testes were cultured on mitotically inactivated testicular stromal cells (TSCs) derived from cats, dogs and mice, and mouse embryonic fibroblasts (MEFs). The formation and growth of colonies derived from SSCs cultured on each type of feeder cell were identified at passage 0, and the morphology, alkaline phosphatase (AP) activity and expression of SSC‐specific genes in surviving colonies were investigated at passage 4. Among these diverse feeder cells, TSCs from cat showed the greatest colony formation, growth and maintenance of FSSCs, and SSC colonies cultured by passage 4 showed a typical dome‐shaped morphology, AP activity and expression of SSC‐specific genes (NANOG, OCT4, SOX2 and CD9). Accordingly, these results demonstrate that feline TSCs could be used as feeder cells to support the establishment and maintenance of SSCs from domestic cats. 相似文献
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van Putten MH 《Science (New York, N.Y.)》1999,284(5411):115-118
The coalescence of a neutron star and a black hole in a binary system is believed to form a torus around a Kerr black hole. A similarly shaped magnetosphere then results from the remnant magnetic field of the neutron star. In the strong-field case, it contains a cavity for plasma waves located between the barrier of the gravitational potential and the surrounding torus. This cavity may be unstable to superradiance of electromagnetic waves. Superradiant amplification of such waves, initially excited by turbulence in the torus, should inflate into a bubble in a time as short as approximately 0.75 (1 percent/&cjs3539;epsilon&cjs3539;2)(M/7M middle dot in circle) seconds approximately 0.15 to 1.5 seconds, assuming an efficiency &cjs3539;epsilon&cjs3539;2 = 0.5 to 5 percent and a mass M = 7M middle dot in circle. These bubbles may burst and repeat, of possible relevance to intermittency in cosmological gamma-ray bursts. The model predicts gamma-ray bursts to be anticorrelated with their gravitational wave emissions. 相似文献
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Lichtenegger HC Schöberl T Bartl MH Waite H Stucky GD 《Science (New York, N.Y.)》2002,298(5592):389-392
Biominerals are widely exploited to harden or stiffen tissues in living organisms, with calcium-, silicon-, and iron-based minerals being most common. In notable contrast, the jaws of the marine bloodworm Glycera dibranchiata contain the copper-based biomineral atacamite [Cu2(OH)3Cl]. Polycrystalline fibers are oriented with the outer contour of the jaw. Using nanoindentation, we show that the mineral has a structural role and enhances hardness and stiffness. Despite the low degree of mineralization, bloodworm jaws exhibit an extraordinary resistance to abrasion, significantly exceeding that of vertebrate dentin and approaching that of tooth enamel. 相似文献
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Earthworms (Oligochaeta,Lumbricidae) and mycobacteria 总被引：4，自引：0，他引：4
Fischer OA Matlova L Bartl J Dvorska L Svastova P du Maine R Melicharek I Bartos M Pavlik I 《Veterinary microbiology》2003,91(4):325-338
The objective of the study was to define the role of earthworms in the survival of mycobacteria in animal populations. In 13 sampling sites mycobacteria were detected in 53 (5.5%) samples of faeces and parenchymatous tissues from animals, in 25 (7.3%) environmental and in nine (8.2%) earthworm samples. In cattle and goat farms affected by Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) of IS900 restriction fragment length polymorphism (RFLP) type B-C1 was isolated from 37 (4.6%) faecal samples, three (1.4%) environmental and one (3.1%) earthworm sample. Investigations of aviaries affected by avian tuberculosis detected M. avium of genotype IS901+ and IS1245+ in six (7.9%) bird's faecal and in four (4.4%) environmental samples. M. avium (genotype IS901- and IS1245+) was detected in four (4.4%) and M. abscessus in one (1.1%) environmental sample. M. avium of genotype IS901- and IS1245+ and M. gastri were isolated from three (6.4%) earthworm samples. In pig farm with mycobacteriosis M. avium of genotype IS901- and IS1245+ was detected in five (20.0%) faecal samples from pigs and in four (12.9%) environmental samples. M. scrofulaceum was isolated in one (4.6%) sample of Lumbricus rubellus. In laboratory experiments identical RFLP types of M. paratuberculosis were isolated from bodies and faeces of earthworms 1-2 days after the last contact with the faeces contaminated with the same RFLP type of M. paratuberculosis. The results suggest that earthworms may become vectors of mycobacteria. 相似文献
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Dvorska L Matlova L Bartos M Parmova I Bartl J Svastova P Bull TJ Pavlik I 《Veterinary microbiology》2004,99(3-4):239-250
This study surveys 2,593,348 cattle slaughtered between 1996 and 2000, and further investigates 571 (0.02%) animals found to have tuberculous lesions. Culture of 346 randomly selected tissue samples from animals younger (n = 215) and older (n = 131) than 2 years, isolated mycobacteria from 91 animals (26.3%). These included 74 Mycobacterium avium subsp. avium isolates of IS901+ and IS1245+ genotype and serotype 2, 13M. avium subsp. hominissuis isolates of IS901- and IS1245+ genotype and serotypes 8 (n = 7) and 4 (n = 6), two M. chelonae, one M. avium subsp. paratuberculosis (RFLP type B-C1), and one M. terrae. Culture of mesenteric lymph node samples obtained 66 isolates of M. avium complex (MAC) and four isolates of other mycobacterial species. M. bovis was significantly absent from all samples. Mycobacteria were more frequently (P = 0.01) isolated from tissues of animals under 2 years (34.4%) than animals over 2 years (13.0%). IS901 and IS1245 RFLP methods were used to type 17 randomly selected MAC isolates, virulent after intramuscular inoculation of pullets, from 17 different cattle herds. These revealed 11 distinct IS901 RFLP types and three IS1245 RFLP profiles. Polyclonal infection of individual animals was detected by IS901/IS1245 typing in 2 of the 17 selected isolates. 相似文献
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The current investigations were undertaken to study the mechanism of the adverse effect of phytoestrogens on the function of bovine granulosa (follicles >1< cm in diameter) and luteal cells from day 1–5, 6–10, 11–15, 16–19 of the oestrous cycle. The cells were incubated with genistein, daidzein or coumestrol (each at the dose of 1 × 10?6 m ). The viability and secretion of estradiol (E2), progesterone (P4) and oxytocin (OT) were measured after 72 h of incubation. Moreover, the expression of mRNA for neurophysin‐I/OT (NP‐I/OT; precursor of OT) and peptidyl‐glycine‐α‐amidating monooxygenase (PGA, an enzyme responsible for post‐translational OT synthesis) was determined after 8 h of treatment. None of the phytoestrogens used affected the viability of cells except for coumestrol. The increased secretion of E2 and P4 was only obtained by coumestrol (p < 0.05) from granulosa cells from follicles <1 cm in diameter and decreased from luteal cells on days 11–15 of the oestrous cycle, respectively. All three phytoestrogens stimulated (p < 0.05) OT secretion from granulosa and luteal cells in all stages of the oestrous cycle and the expression of NP‐I/OT mRNA in the both types of cells. The expression of mRNA for PGA was stimulated (p < 0.05) by daidzein and coumestrol in granulosa cells, and by genistein and coumestrol in luteal cells. In conclusion, our results demonstrate that these phytoestrogens can impair the ovary function in cattle by adversely affecting the synthesis of OT in follicles and in corpus luteum. However, their influence on the ovarian steroids secretion was less evident. 相似文献
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