奶牛MTT比色法的最佳条件探讨

为建立奶牛淋巴细胞增殖反应MTT比色法,对试验条件进行了研究。应用L16(45)正交试验,对影响MTT比色法的四个主要因素,包括ConA浓度、细胞浓度、培养液小牛血清浓度及培养时间进行了比较和探索。试验表明几个因素对其增殖反应都有显著影响(P<0.05),且最佳反应条件为:15μg/mL的ConA、1×106/mL细胞浓度、10%小牛血清及60h的培养时间;影响增殖反应的先后顺序为细胞浓度、ConA浓度、培养时间及血清浓度。     

Chemical changes of kenaf core binderless boards during hot pressing (I): influence of the pressing temperature condition

Self-bonding is the main factor of the performance expression of binderless boards, and therefore its clarification is considered to be an important issue. For this purpose, a series of chemical analyses were conducted on kenaf core binderless boards and their chemical changes during the hot-pressing process are discussed in this article. First of all, binderless boards were prepared from kenaf core powder at different pressing temperatures (without steam-explosion process) and were used for chemical analyses after they were reduced into powders and extracted with methanol. To investigate their chemical changes, lignin, holocellulose, and neutral sugar contents were determined, Fourier transform infrared (FTIR) spectra were recorded, and the nitrobenzene oxidation procedure was applied. As a result, it was found that parts of lignin and hemicelullose were decomposed during the hot-pressing process; however, the contribution of the resulting fractions to selfbonding was not observed. In addition, progress of condensation reactions in lignin and the formation of chemical bonds by low molecular weight conjugated carbonyl compounds in methanol extractives were observed. Thermal softening of lignin is also suggested to play an important role in the expression of board performance.     

Sperm competition and the evolution of sperm form and function in mammals

Sperm competition is a powerful selective force that has influenced many reproductive traits in males and females although additional evolutionary explanations may help to understand the diversity of mammalian reproduction. Sperm morphology varies considerably in mammals with extreme examples in several rodent lineages in which a wide range of sizes and complex head morphologies have been identified. Mammalian spermatozoa also differ in function, with swimming velocity and trajectory showing much divergence. Underlying processes mediating function have received little attention so far, but differences in timing and proportion of sperm undergoing capacitation or acrosomal exocytosis may be related to variation in signalling processes. Furthermore, energy required for sperm functions (such as motion, signalling and overall maintenance of cell integrity) can be produced and consumed, following different patterns among species and this could be the result of several selective forces. A more thorough understanding of the diversity in structure and function of sperm cells, and underlying selective forces, may help us develop better methods to assess them taking into account particulars and generalities of sperm form and performance. Such tests could then become more reliable in estimations of the impact of cryopreservation or effect of changes in the environment and their relevance for fertility.     

应用PCR技术检测鹅细小病毒

根据鹅细小病毒GPVH1株结构蛋白VP1与VP3编码基因非重叠核苷酸序列设计了一对引物GPR1 /GPR2 ,用这对引物对感染器官内的GPR和接种鹅胚增殖的GPV进行PCR扩增 ,其结果引物GRP1 /GPR2能特异性地扩增GPVVP1 VP3区段核苷酸序列 ,扩增出与设计核苷酸片段大小相符的 0 6kb的序列 ,而对照的鹅副粘病毒cDNA及鸭瘟病毒 (DPR)DNA对照组均出现阴性结果。     

牛副结核检疫中的非特异性干扰

给犊牛接种各种分枝杆菌，然后以副结核ＰＰＤ进行变态反应试验，观察各分枝杆菌感染对副结核变态反应的干扰；从各种分枝杆菌感染牛群采取血清进行副结核ＥＬＩＳＡ检测，以观察各分枝杆菌血清对牛副结核ＥＬＩＳＡ的干扰。结果：多种分枝杆菌，特别是鸟胞内分枝杆菌、瘰疬分枝杆菌的感染可干扰副结核变态反应；部分结核牛血清干扰副结核ＥＬＩＳＡ的检测     

Bovine herpesvirus 4-associated postpartum metritis in a Spanish dairy herd

In more than 10 Spanish dairy cows, a bovine herpesvirus 4 (BHV4) associated postpartum metritis was confirmed by virus isolation, BHV4-glycoprotein B (gB) PCR and/or serology. In this study, 12 cows with, and, at the time of sampling, 3 cows without clinical signs of acute postpartum metritis from one large dairy herd in Spain were examined for bacterial and viral infections. Blood, placenta/caruncles and uterine contents were collected between day 1 and day 20 post-calving, and examined for the presence of bacteria and for viruses by virus isolation, BHV4 DNA by BHV4-gB PCR and/or BHV4 antibody titres. Bovine herpesvirus 4 was detected in 83% of the cases with clinical signs of acute postpartum metritis by virus isolation and/or BHV4-gB PCR. An increase of BHV4 antibodies was detected in all examined postpartum metritis cows and in the 3 cows without clinical metritis. Two of these 3 cows developed severe metritis a few dayss after collecting the first blood sample. A concurrent infections of BHV4 and bacteria, mainly Arcanobacterium pyogenes and Streptococcus sp., were detected in 73% of the examined uterine contents collected from postpartum metritis affected cows. This case-report study showed a clear association between BHV4 infections and acute postpartum metritis in dairy cows. In addition, the BHV4-associated postpartum metritis appeared to be an emerging syndrome in this Spanish herd.     

雏鸡马立克氏病疫苗免疫后细胞免疫功能的变化

雏鸡用马立克氏病(MD)三价疫苗免疫后,其脾脏和胸腺T淋巴细胞增殖反应比未免疫健康对照雏鸡和以火鸡疱疹病毒(HVT)疫苗免疫的雏鸡显著增强(P<0.05),外周血液T辅助细胞(T_M)和单核细胞数量显著增加(P<0.01或P<0.05);雏鸡HVT疫苗免疫后,脾脏T淋巴细胞增殖反应比未免疫健康对照雏鸡显著增强(P<0.05),而胸腺T淋巴细胞增殖反应虽有增强,外周血液T_M数量虽有增加,但均无统计学显著性差异(P>0.05).     

基于平行反应监测验证技术分析绵羊胚胎骨骼肌蛋白质组数据

旨在对绵羊胚胎骨骼肌蛋白质组学数据进行分析,为阐明绵羊胚胎骨骼肌生长发育机制奠定基础。前期试验应用串联质谱定量法（tandem mass tag,TMT）对成年中国美利奴绵羊妊娠第85（D85）、105（D105）和135天（D135）的胚胎背最长肌进行蛋白质定量,并对D85/D105、D105/D135和D85/D135 3个比较组进行分析。本试验在此基础上,利用KEGG和平行反应监测（parallel reaction monitoring,PRM）等数据分析方法对3个比较组绵羊胚胎骨骼肌上、下调差异丰度蛋白质进行分析和验证,并对候选蛋白质进行生物信息学分析。本研究对肌纤维成熟分化标志性蛋白肌球蛋白重链（myosin-2 isoform X2,MYH）进行PRM靶向定量验证,结果表明,其变化趋势与绵羊胚胎肌纤维成熟分化趋势相符。本研究对上调差异丰度蛋白和下调差异丰度蛋白的KEGG分析结果表明,D105/D85比较组中上调差异丰度蛋白质显著富集于胰岛素等信号通路,D135/D105和D135/D85比较组中下调差异丰度蛋白质显著富集于DNA复制和蛋白质消化吸收等信号通路。与肌肉发育相关的cAMP依赖性蛋白激酶A催化亚基α（PRKACA）和葡萄糖转运蛋白成员4（GLUT4）蛋白均显著富集于胰岛素信号通路中,生物信息学分析显示,这两个蛋白质的理论分子量分别为121.73和20.64 ku,分别有147、12个带正电荷的氨基酸残基和135、12个带负电荷的氨基酸残基;理论等电点分别为8.81和6.54;亲水性平均系数分别为-0.408和0.811;PRKACA蛋白无N端糖基化位点,有45个磷酸化位点;GLUT4蛋白有1个N端糖基化位点,25个磷酸化位点;PRKACA蛋白三级结构与CAMP-2依赖蛋白激酶a嵌合融合的晶体结构相似度为85%,GLUT4蛋白三级结构与人葡萄糖转运蛋白GLUT1的相似性为78%。本研究表明,PRM定量验证趋势与绵羊胚胎肌纤维成熟分化趋势相符,PRKACA和GLUT4蛋白具有丰富的磷酸化修饰位点,并参与胰岛素信号通路调控,是重要的候选蛋白。     

Molecular Evidence for Persistence of Anaplasma phagocytophilum in the Absence of Clinical Abnormalities in Horses after Recovery from Acute Experimental Infection

Background: Anaplasma phagocytophilum infects several mammalian species, and can persist in sheep, dogs, and calves. However, whether this organism persists in horses or induces long-term clinical abnormalities is not known.
Objectives: To evaluate whether A. phagocytophilum can persist in horses and to document clinical findings for 3 months after complete recovery from acute disease.
Animals: Five clinically normal adult horses that had recovered spontaneously from experimentally induced acute disease caused by a Swedish equine isolate of A. phagocytophilum .
Methods: Horses were monitored for up to 129 days post inoculation (PI) by daily clinical examination and at least alternate day blood sampling for evidence of A. phagocytophilum on polymerase chain reaction (PCR) and blood smears. All horses were euthanized and underwent postmortem examination.
Results: All horses were periodically PCR positive after recovery from acute infection. Before day 66 PI 2 horses were persistently PCR negative whereas 3 horses were intermittently PCR positive. Subsequently, 4 of 5 horses were intermittently PCR positive, particularly after stress mimicking interventions. One animal was positive immediately before postmortem examination. Clinical abnormalities related to persistence of anaplasma were not observed. No specific changes were found at postmortem examination, and all sampled tissues from all horses were negative on PCR for A. phagocytophilum .
Conclusions and Clinical Importance: Infection with A. phagocytophilum can persist in the horse for at least 129 days. However, the continued presence of the organism is not associated with detectable clinical or pathological abnormalities.