不同黑麦草品种种子萌发期抗旱性研究

以0、5%、10%、15%、20%的聚乙二醇(PEG-6000)溶液为干旱胁迫条件,对13个不同用途黑麦草品种种子的相对发芽率、发芽势、发芽指数、种子活力指数和胚根/胚芽值进行测定并聚类分析。结果表明,在种子萌发期,高抗旱性的黑麦草品种是沃土、俄勒冈四倍体、特高、雅晴、首相、抗锈王、麦迪和剑宝;抗旱性偏弱的品种是顶峰、夜影Ⅱ、潘多拉和匹克;冬绿的抗旱性最差。     

Development and evaluation of enzyme-linked immunosorbent assay based on recombinant inorganic pyrophosphatase gene antigen for the detection of Mycoplasma suis antibodies

The recombinant ppa protein of Mycoplasma suis migrated to 21 kDa. Using this antigen, an ELISA system to detect the antibody against M. suis infection in swine was established. The rELISA demonstrated 98.5% specificities among negative samples and 96.9% sensitivity among positive samples with M. suis infection. A comparison of this ELISA system with an indirect hemagglutination assay (IHA) test using 132 swine samples revealed that the positive rate was 34.0% in ELISA and 28.0% in IHA. Compared with IHA, the present rELISA system using recombinant ppa antigen significantly improves the specificity, sensitivity, and stability for serodiagnosis of M. suis infection in swine.     

Effect of chito-oligosaccharide on growth performance, intestinal barrier function, intestinal morphology and cecal microflora in weaned pigs

A total of 180 weanling pigs (21 ± 3 d of age; 5.98 ± 0.04 kg) were used to investigate the effect of chito-oligosaccharide (COS) on growth performance, intestinal barrier function, intestinal morphology, and cecal microflora. Based on initial BW, gender and litter, the pigs were given 5 treatments during a 14-d feeding experiment, including a basal diet (control), 3 diets with COS supplementation (200, 400, or 600 mg/kg), and a diet with colistin sulfate (CSE) supplementation (20 mg/kg). Six randomly selected pigs from each treatment were used to collect serum, duodenal, jejunal, ileal, and cecal samples on d 7 and 14 postweaning. From d 1 to 7 postweaning, pigs fed COS or CSE had greater ADG and ADFI compared with the control pigs. From d 1 to 14, diets with either 400 or 600 mg/kg COS, or 20 mg/kg CSE increased (P < 0.05) ADG and G:F compared with the control diet. No significant differences were observed in ADG, ADFI, and G:F between the pigs fed COS and CSE. Pigs fed either 400 or 600 mg/kg COS, or 20 mg/kg CSE had less (P < 0.05) diamine oxidase (DAO) in the serum, but greater concentration of (P < 0.05) DAO in jejunal mucosa, than the control pigs on d 7 postweaning. Treatments did not affect villous height and crypt depth of the duodenum, jejunum, or ileum. Pigs fed COS at 400 mg/kg had greater (P < 0.05) concentration of Bifidobacteria and Lactobacilli in the cecum than pigs fed the control diet and CSE diet on d 7 postweaning. Supplementation of COS or CSE decreased (P < 0.05) the population of cecal Staphylococcus aureus compared with the control diet on d 7 postweaning. The number of cecal Bifidobacteria in pigs fed 600 mg/kg COS was greater (P < 0.05) than that of pigs fed the control diet or CSE diet on d 14 postweaning. No significant differences were observed in Escherichia coli counts in the cecum among treatments. The present results indicate that dietary supplementation of COS at 400 or 600 mg/kg promotes growth performance and improves gut barrier function, increases the population of Bifidobacteria and Lactobacilli, and decreases S. aureus in the cecum of weanling pigs.     

PPARγ和PCNA在口腔鳞癌组织的表达及临床意义

目的 探讨过氧化物酶体增殖物激活受体(PPARγ)与增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)在口腔鳞癌中(oral squamous-cell carcinoma,OSCC)的表达及其生物学意义.方法 采用免疫组织化学和流式细胞术检测50例口腔鳞状细胞癌、癌旁黏膜(距瘤缘2 cm)和切缘正常黏膜(距瘤缘≥5 cm,镜下未见癌浸润)标本中PPARγ和PCNA的表达.结果 PPARγ在癌组织中的阳性表达率为68.0% (34/50),高于癌旁组织(26.0%,13/50)和正常黏膜组织(2.0%,1/50) (P ＜0.05);PCNA在癌组织中的阳性表达率为72.0% (36/50),高于癌旁组织(26.0%,13/50)和正常黏膜组织(4.0%,2/50)(P＜0.05).流式细胞术检测PPARγ在鳞癌组织中的表达为(396.56±33.39),明显高于癌旁组织(333.36±15.93)及正常口腔黏膜组织(289.28±13.80)(P＜0.05).PCNA在鳞癌组织中的表达为(543.11±41.55),明显高于癌旁组织(456.97±23.86)和正常口腔黏膜组织(409.40±40.07) (P ＜0.05).PPARγ和PCNA的表达与细胞分化程度、淋巴结转移均有相关性(PPARγ,r分别为0.497、0.392,P＜0.05;PCNA,r分别为0.324、0.561,P＜0.05),且二者在口腔鳞癌中的表达呈正相关.结论 口腔鳞癌组织中PPARγ和PCNA的表达均升高,可能与口腔鳞癌的发生、发展相关.     

幼建鲤生物素缺乏的病理组织学观察

本试验旨在研究生物素缺乏幼建鲤的组织器官病理变化。将 ４００尾平均体重为（７．７２±０．０２）ｇ的幼建鲤随机分为２组（每组４个重复,每个重复５０尾鱼）,分别饲喂生物素含量为 ０．０１０（缺乏组）和 ０．１５１ｍｇ／ｋｇ（对照组）的试验饲料 ６３ｄ。结果表明：生物素缺乏导致幼建鲤的肠黏膜上皮细胞变性、坏死、脱落;肝细胞变性、肿胀;后肾肾小管细胞变性、肿胀;心脏肌纤维溶解、断裂,肌间间隙变宽;肌肉肌纤维萎缩、断裂,肌横纹模糊不清或消失;鳃小片粘连,严重者坏死、脱落,部分鳃弓处发生充血。由此得出,生物素缺乏会造成幼建鲤组织器官不同程度的病理损伤。     

苜蓿鲜草和青饲玉米对奶牛生产性能和乳品质的影响

探讨日粮中添加苜蓿鲜草和青饲玉米对奶牛生产性能及其乳成分的影响,本试验选用荷斯坦泌乳奶牛20头,随机分为2组,对照组饲喂秸秆和精料补充料;试验组饲喂苜蓿鲜草、青饲玉米和精料补充料日粮。试验结果表明,日粮中添加苜蓿鲜草和青饲玉米,可极显著提高奶牛的生产性能和乳脂率(P<0.01),显著提高干物质采食量和乳蛋白含量(P<0.05)。     

pVAX1/SjTSP2 DNA疫苗免疫预防小鼠日本血吸虫病的效果评估

为评估SjTSP2分子作为日本血吸虫DNA疫苗候选抗原分子的潜力,本实验扩增了编码该分子的DNA片段,构建了重组真核质粒pVAX1/SjTSP2,检测其在哺乳动物细胞中表达情况后,通过基因枪轰击法免疫小鼠,应用ELISA、流式细胞术等检测重组质粒诱导的免疫反应,计算减虫减卵率,评估对小鼠日本血吸虫病的免疫保护效果。间接免疫荧光试验结果显示该质粒能在293T细胞中表达。质粒免疫小鼠诱导了显著升高的特异性IgG抗体和IFN-γ、IL-4等细胞因子。小鼠免疫保护试验结果表明,免疫组小鼠虫荷数较PBS对照组增加12.4%(P=0.368),但肝组织虫卵减少10.01%(P=0.486)。说明制备的DNA疫苗能刺激小鼠产生较强的免疫反应,但诱导的免疫保护作用并不理想,为血吸虫DNA疫苗研究提供了参考数据。     

宁夏玉米营养成分近红外分析模型建立与应用

研究采集宁夏区内各市县(固原、海原、同心、中卫、中宁、永宁、平罗)抽取玉米样品120批,用近红外分析仪扫描定标样品集获得玉米近红外光谱图,利用偏最小二乘法建立模型,并分别经过无预处理、均值中心化、标准正态变量转换、一阶导数、标准正态变量转换结合去趋势校正(SNV+D)预处理光谱,获得水分、粗蛋白、粗脂肪、粗纤维预测模型,分别是经过MC、SNV+D、SNV+D、SNV+D光谱预处理后效果最好。预测决定系数R² _p分别为0.951、0.976、0.728、0.897,相对分析误差RPD除粗脂肪为2.62外,其他均大于3的近红外预测模型,通过预测模型验证集验证后,并对模型预测值与实测值进行U检验,结果为差异不显著(P>0.05)。该近红外预测模型对玉米中水分、粗蛋白、粗纤维具有较佳预测效果,粗脂肪的预测精度有待进一步提高。     

高粱根际微生物研究进展

根据近年来国内外关于高粱根际微生物的研究成果,综述了高粱根际微生物的多样性、主要影响因素、高粱根际微生物对高粱生长的影响、根际促生菌对高粱重金属携带能力的影响及土壤的生物修复等最新研究进展,这些研究成果分析了高粱根际微生物多样性对植株生长、生态环境等的影响意义及交互作用,并展望了今后高粱根际微生物方向需要深入研究的问题...     

气肿疽梭菌CctA基因的原核表达及其间接ELISA检测方法的建立

研究旨在原核表达气肿疽梭菌细胞毒素A （CctA）基因,用纯化的重组蛋白建立其间接ELISA检测方法,a。利用大肠杆菌密码子的偏爱性优化CctA基因序列,克隆至原核表达载体pET-28a （+）,双酶切鉴定原核表达质粒pET28a-CctA并测序。将重组质粒转入大肠杆菌,经IPTG诱导得到高表达的重组CctA包涵体蛋白。包涵体蛋白变性后经镍（Ni）柱纯化,SDS-PAGE检测其纯化效果。以豚鼠抗气肿疽梭菌抗血清为一抗,用Western blotting方法检测重组CctA蛋白的反应原性。用棋盘滴定法建立间接ELISA检测方法,以复性后的重组CctA蛋白作为检测抗原,摸索抗原包被浓度、封闭液的种类及浓度、抗体的最适稀释度和反应条件等。选用3批气肿疽灭活疫苗免疫豚鼠后采集血清,同时用攻毒和间接ELISA两种方法验证疫苗的免疫效力。质粒双酶切结果显示,得到大小约853 bp的条带,与预期相符,且测序结果正确。SDS-PAGE结果表明,成功表达并纯化大小为35 ku的重组CctA蛋白。Western blotting结果显示,豚鼠抗气肿疽梭菌抗血清与重组CctA蛋白具有良好的反应原性。建立的间接ELISA法的最适条件为：抗原的包被浓度为0.5 μg/mL,于4 ℃包被过夜;封闭液选择10%胎牛血清,37 ℃孵育2 h;二抗的稀释度为1：8 000;室温避光显色10 min后终止反应,测定D_{450 nm}值。当P/N>4.6时,间接ELISA法检测结果与豚鼠攻毒试验结果拟合度较好。本研究成功表达CctA基因并纯化了重组CctA蛋白,建立的以重组CctA蛋白为检测抗原的间接ELISA检测方法,有望成为气肿疽灭活疫苗免疫效果验证的替代方法。