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Melatonin has been reported to improve the in vitro development of embryos in some species. This study was conducted to investigate the effect of melatonin supplementation during in vitro maturation (IVM) and development culture on the development and quality of porcine embryos. In the first experiment, when the in vitro fertilized embryos were cultured with different concentrations of melatonin (0, 10, 25 and 50 ng/ml) for 8 days, the blastocyst formation rate of embryos cultured with 25 ng/ml melatonin (10.7%) was significantly increased (p < 0.05) compared to the control embryos cultured without melatonin (4.2%). The proportion of DNA‐fragmented nuclei in blastocysts derived from embryos cultured with 50 ng/ml melatonin was significantly lower (p < 0.05) than that of embryos cultured without melatonin (2.1% vs 7.2%). In the second experiment, when oocytes were cultured in the maturation medium supplemented with different concentrations of melatonin (0, 10, 25 and 50 ng/ml), fertilized and then cultured with 25 ng/ml melatonin for 8 days, there were no significant differences in the rates of cleavage and blastocyst formation among the groups. However, the proportions (2.7–5.4%) of DNA‐fragmented nuclei in blastocysts derived from oocytes matured with melatonin were significantly decreased (p < 0.05) compared to those (8.9%) from oocytes matured without melatonin, irrespective of the concentration of melatonin. Our results suggest that supplementation of the culture media with melatonin (25 ng/ml) during IVM and development has beneficial effects on the developmental competence and quality of porcine embryos.  相似文献   
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Conversion of methane to higher hydrocarbons by its low-temperature activation without forming undesirable carbon oxides is of great scientific and practical importance. Methane can be highly activated, yielding high rates of conversion to higher hydrocarbons and aromatics (10 to 45 percent) at low temperatures (400° to 600°C), by its reaction over H-galloaluminosilicate ZSM-5 type (MFI) zeolite in the presence of alkenes or higher alkanes. The methane activation results from its hydrogen-transfer reaction with alkenes.  相似文献   
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To establish chronic infections, viruses must develop strategies to evade the host's immune responses. Many retroviruses, including mouse mammary tumor virus (MMTV), are transmitted most efficiently through mucosal surfaces rich in microbiota. We found that MMTV, when ingested by newborn mice, stimulates a state of unresponsiveness toward viral antigens. This process required the intestinal microbiota, as antibiotic-treated mice or germ-free mice did not transmit infectious virus to their offspring. MMTV-bound bacterial lipopolysaccharide triggered Toll-like receptor 4 and subsequent interleukin-6 (IL-6)-dependent induction of the inhibitory cytokine IL-10. Thus, MMTV has evolved to rely on the interaction with the microbiota to induce an immune evasion pathway. Together, these findings reveal the fundamental importance of commensal microbiota in viral infections.  相似文献   
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Feline Chronic Gingivostomatitis Syndrome (FCGS) is a common disease in clinical practice. Among the therapeutic options available, long-acting corticosteroids are frequently used due to their anti-inflammatory and immunosuppressive properties. Although they may improve the clinical symptoms, they can lead to a progressive form of the disease that becomes refractory to treatment. Furthermore, their direct relationship with type II diabetes mellitus (DM) is well known. Consequently, these drugs are controversial and not recommended for routine management of FCGS. Recombinant feline interferon-omega (rFeIFN-ω) is an immunomodulatory compound. Recently, its daily oral administration has been shown to be successful in treating refractory cases of FCGS. This case study describes two clinical cases of type II DM complicated by FCGS. Both animals were calicivirus positive and they had been previously treated with long-acting corticosteroids, which may have been the major cause of DM. The two cats were treated with glargine insulin (Lantus, starting dose 1 IU/cat twice daily (BID)), achieving remission 10 and 18 weeks later respectively. Considering the difficulty with control of FCGS in these animals, an oral daily dose of rFeIFN-ω was started as an alternative to long-acting corticosteroids. In both cats oral clinical signs gradually improved and 60 days after the start of therapy the owners reported a significant relief of pain during mastication. According to the authors’ knowledge, this is the first case report that describes the successful use of rFeIFN-ω in the management of FCGS in type II diabetic cats, in which long-acting corticosteroids are contraindicated.  相似文献   
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本研究以人参愈伤悬浮细胞为材料,在其生长的第28天添加1×10^-3mg/L水杨酸,测定水杨酸添加后,过氧化物酶、多酚氧化酶和苯丙氨酸解氨酶等3种酶在72h内的变化及皂苷含量,结果表明:水杨酸添加后对过氧化物酶和苯丙氨酸解氨酶的活力影响最大,分别在24h和48h达到最大峰值,在18h开始影响多酚氧化酶的活力,培养物生长的第28天添加水杨酸可以明显提高人参愈伤组织中皂苷的合成。确定添加水杨酸后24h提取总RNA,进行cDNA-RDA分析,筛选差异片段。确定差异基因并在GenBank中注册,注册号为FE900130。为探讨水杨酸作为诱导子对人参次生代谢的影响奠定基础。  相似文献   
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通过对比火炬树幼林地树木生长及光合生理指标,配合土壤水分测定,对河北平山片麻岩石质山区不同微地形集水保墒措施进行了优化。结果表明:①不同集水保墒措施下,翼式鱼鳞坑+保水剂(YY+B)、翼式鱼鳞坑+石子(YY+S)都能有效提高土壤的保水能力,其中YY+S持续时间较长,雨后第6天,YY+S比CK(不做处理)的土壤含水量高出43.19%。到雨后第14天,YY+S的土壤含水率仍大于CK。②YY+S和翼式鱼鳞坑+植物覆盖(YY+Z)对树木生长的影响最大。YY+S处理的火炬树树高年生长量为12.09 cm,极显著高于对照3.03倍。YY+S、YY+Z处理的地径年生长量分别为0.43、0.40 cm,是CK地径生长量的2.15、2.00倍。③YY+Z、YY+B及YY+S处理树木的净光合速率显著高于翼式鱼鳞坑(YY)和CK处理,增幅52.91%~59.23%。④各种处理方法火炬树幼树的光响应曲线趋势基本一致,各处理的光补偿点为500 mol.m-2.s-1,光饱和点为1 600 mol.m-2.s-1。随着光强的增加,光合有效辐射(PAR)(600~2 000μmol.m-2.s-1)时,YY+B及YY+Z处理幼树的净光合速率显著高于对照。从降雨后土壤含水量的变化趋势、年终树木生长量、光合速率、光响应曲线综合看来,翼式鱼鳞坑+石子覆盖的集水保墒效果最优。  相似文献   
7.
Male infertility is one of the prime concerns of dairy cattle production. The study was designed to find out differentially expressed proteins in categorized crossbred (Holstein Friesian × Sahiwal) bull semen to serve as potential biomarkers for male infertility. Frozen crossbred bull semen with satisfactory phenotypic records were defined as “good” and “poor” based on their fertility rates. A total of 1,547 proteins were detected in bull spermatozoa using liquid chromatography–mass spectrometer (LC‐MS/MS) analysis. Results revealed that 558 (36.1%) and 653 (42.2%) proteins were expressed to good and poor quality bull spermatozoa, respectively. A total of 336 proteins (21.7%) were reported to be unique for both good and poor quality bull semen, and among the common proteins, 224 (66.7%) and 112 (33.3%) were up‐ and downregulated in good and poor quality categorized bull semen, respectively. Gene Ontology analysis of global proteomes identified different signalling pathways, and most of them were related to cellular motility, immune systems as well as cellular metabolisms. The distinctive presence of some of the proteins may provide an insight into the molecular mechanistic role played by these proteins in crossbred bull infertility.  相似文献   
8.
Follicle-associated epithelium (FAE) in the intestinal Peyer's patches contains M cells that deliver pathogens to organized lymphoid tissue. Development of Peyer's patches, FAE, and M cells was found to be impaired in mice that had no B cells. Transgenic expression of membrane-bound immunoglobulin M restored B cells and FAE development. The lack of M cells abrogated infection with a milk-borne retrovirus. Thus, in addition to secretion of antibodies and presentation of antigens, B cells are important for organogenesis of the mucosal immune barriers.  相似文献   
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