Screening of Probiotics Inhibiting E. coli K88 in vitro

The probiotics tested in the experiment were isolated from the intestinal of weaning piglets.The isolated probiotics and E.coli K88 were inoculated into the culture of intestinal porcine epithelial cell-1 (IPEC-1).The activity of lactate dehydrogenase (LDH) in the supernatant was measured after incubating for 2.5 h.At the same time, the probiotics and E.coli K88 were co-cultured in vitro, the number of E.coli K88 was counted and the probiotics which could be resistant to the E.coli K88 were selected 2.5 h later.The results showed that the Lactobacillus casei and Bacillus coagulans could significantly reduce LDH activity (P<0.05), decrease the damage of E.coli K88; Bacillus coagulans could inhibit the growth of E.coli K88.At the same time, Bacillus coagulans could resist high temperature, acid and bile salt.The results showed that Bacillus coagulans strains had great potential as the application of probiotics strains.The methods could be used as a model of screen probiotics which could inhibit the growth of E.coli K88 in vitro.     

Research Lactobacillus rhamnosusFermented Herbal and Bacillus subtilis Complex on Immune Performance,E.coli Infection of Broiler

This experiment was designed to study the complex of Lactobacillus rhamnosus fermented herbal and Bacillus subtilis on White Feather broiler immunity performance and impact of Escherichia coli infection.360 one-day-old broiler chickens were randomly divided into 3 groups with 4 replicates in each group and 30 chickens per replicate.The pretrial period lasted for 7 d,and the experiment lasted for 35 d.The chickens in the group Ⅰ(positive control group) and group Ⅱ(negative control group)were all only fed a basal diet,group Ⅲ was test group,by additive 1% fermented herbal preparations,groups Ⅱ and Ⅲ were intraperitoneal injection of 1 mL E.coli at 35 d,broiler mortality,immune organ index,cecalmicroflora content,immunoglobulin levels,IL-2 and IL-6 content were tested.The results showed that injection of E.coli caused massive death of chickens,group Ⅱtook up to 75.00%,it was significantly higher than groups Ⅰ and Ⅲ (P < 0.05),the mortality in group Ⅲ was significantly lower than group Ⅱ(P < 0.05),was only 23.33%.Injection of E.coli maked spleen index and thymus index of group Ⅱincreased significantly (P < 0.05),the spleen index and thymus index of groups Ⅰ and Ⅲ were no significant difference (P > 0.05).E.coli counts was significantly decreased after injectionin group Ⅲ (P < 0.05),but the number of intestinal Lactobacilli of group Ⅲ was significantly increased (P < 0.05),and inhibited the propagation of E.coli,the counts of E.coli in groups Ⅰ and Ⅲ were no significant difference (P > 0.05).At 42 d,the sIgA of the intestinal fluid in group Ⅲ were higher than that of groups Ⅰ and Ⅱ with 11.99% and 36.56%,respectively(P < 0.05).The serum IgG concentrations of group Ⅲ was higher than that of groupsⅠand Ⅱwith 14.68% and 28.15%,respectively(P < 0.05).At 42 d,the IL-2 content of group Ⅱ was the lowest,it was significantly lower than group Ⅲ(P < 0.05),the IL-6 of group Ⅲ was significantly lower than group Ⅱ(P < 0.05).     

APSIM模型对宁夏海原地区草田轮作系统的适应性

为验证APSIM模型对宁夏海原地区草田轮作系统的适用性,基于10年生苜蓿(Medicago sativa)与小麦(Triticum aestivum)、谷子(Oryza sativa)草田轮作试验数据和同期气象资料,运用APSIM模型对系统进行了模拟。通过试错法和文献记载完成了苜蓿、小麦和谷子几个品种的参数本地化。用统计和图形校验方法评价了APSIM模型模拟结果的可靠性和准确性。结果表明,谷子-小麦-小麦(MWW)、小麦-谷子-小麦(WMW)、谷子-谷子-小麦(MMW)、谷子-小麦-谷子(MWM)、小麦-谷子-谷子(WMM)、小麦-小麦-谷子(WWM)6种轮作方式下产量实测值和模拟值的决定系数R2值范围在0.83至0.98之间,D值范围在0.94至0.99之间,表现出了良好的相关性和一致性。土壤含水量实测值和模拟值的决定系数R2值范围在0.52至1之间,D值范围在0.92至0.97之间,相关性和一致性表现良好。表明APSIM模型对宁夏海原地区苜蓿与小麦、谷子轮作具有较好的模拟能力,可以用来模拟分析该地区草田轮作系统生产潜力和土壤水分动态,对该地区气候变化影响下草田轮作的优化管理具有一定指导意义。     

鞭毛素fliC基因的缺失对肠炎沙门氏菌生物膜形成的影响

为研究肠炎沙门氏菌鞭毛素对其生物膜形成的影响,本研究利用构建的肠炎沙门氏菌鞭毛素编码基因fliC缺失株,检测其缺失性修饰后的生长表型变化及其对生物膜形成的影响。结果显示在表型检测试验中,fliC缺失株在电镜下观察呈无鞭毛形态,在半固体培养基上缺乏运动性,并且不能与肠炎沙门氏菌鞭毛单克隆抗体发生可见的凝集反应。生物膜形成能力定性试验结果表明,肠炎沙门氏菌fliC缺失株生物膜形成大量减少,并且生物膜脆弱,而其回补株能够较好地恢复生物膜的形成;生物膜定量结果进一步证明,鞭毛素fliC基因缺失后肠炎沙门氏菌形成生物膜的能力下降50%左右,以上结果显示鞭毛在肠炎沙门氏菌体外生物膜形成中具有重要作用。     

影响‘小凤兰’根状茎增殖、分化和壮苗的因素研究

以‘小凤兰’根状茎为试材,研究了影响‘小凤兰’根状茎增殖、分化、生根壮苗的因素。结果表明:MS基本培养基、蔗糖30g/L、6-BA 2.0mg/L+NAA 0.5mg/L、活性炭0.5g/L有利于根状茎增殖,而添加20%椰汁和番茄汁40g/L会抑制根状茎增殖。1/2MS基本培养基、蔗糖30g/L、6-BA 2.0mg/L+NAA 0.2mg/L、20%椰汁、1 000lx光照强度有利于根状茎分化,不加活性炭有利于芽分化,但抑制根分化,而添加活性炭则抑制芽分化,促进苗分化。添加土豆泥60g/L显著促进试管苗生长,3~4cm高的苗在培养基1/2MS+6-BA 0.1mg/L+NAA0.5mg/L+蔗糖20g/L+土豆泥60g/L+卡拉粉8g/L+活性炭0.5g/L中培养40d即可移栽。     

高寒地区蛹虫草大米培养基的优化

以引进西藏的6株蛹虫草为试材,对比研究了其菌丝生长速率、出草产出及长势,筛选优良的蛹虫草菌株,并通过正交实验筛选对蛹虫草大米培养基营养成分的最优水平组合。结果表明:蛹虫草"TAAAS1"的菌丝生长速率虽不是最快的,但出草整齐均匀,出草产出高于其它菌株,表明"TAAAS1"菌株是适宜在高寒地区栽培生产的好品种;蛹虫草大米培养基的最优水平组合为蛹粉4g/L,葡萄糖20g/L,硫酸镁2g/L,磷酸二氢钾1.5g/L。     

宁夏日光温室基质栽培不同菜豆适应性种植比较

以10个菜豆品种为试材,在有机基质栽培条件下,比较分析了10个架豆王(菜豆)品种的生育进程、嫩荚特征和产量。结果表明:参试的10个菜豆品种嫩荚均为长圆棍形,长22~30cm、宽7.5~10.00mm、单果11~15g,生长势较强,质地脆嫩,播种到采收55~62d,均可在宁夏引黄灌区进行有机基质栽培;产量最高的是"红珍珠",667m~2产量为2 538.25kg,播种到收获需要60d,前期产量、总产量和采收期均为各品种之首,其次为"西凉架豆王"、"绿奥领秀",前期产量与总产量也较高,可作为主栽品种进行推广种植;"特早一尺嫩"为超早熟品种,播种到收获仅需55d,其单果重最大,前期产量较高,但采收期短,因此,总产量最低,适合作为日光温室休闲期间的轮作倒茬栽培品种推广。     

氮素对巨菌草苗期生长和光合生理特性的影响

以巨菌草为试材,采用水培方法,研究了不同浓度的氮素对巨菌草苗期生长和光合生理特性的影响。结果表明:随着氮素浓度的增加,株高、根总长、根表面积、根体积、分根数、根尖数呈先升后降的趋势,叶片数、叶面积、茎粗则呈上升趋势;净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)先增大后减小,胞间CO2浓度(Ci)则逐渐降低;光合色素、可溶性蛋白质、可溶性糖、脯氨酸含量,过氧化物酶(POD)、超氧化物歧化酶(SOD)活性呈先升后降的趋势,硝态氮(NO-3-N)含量、过氧化氢酶(CAT)活性呈上升趋势,丙二醛(MDA)含量呈下降趋势。研究表明,适量的氮素供应(5.00~10.00mmol/L)可以促进植株生长,提高光合能力,增加渗透调节物质含量、减少MDA含量及提高抗氧化物酶活性,有利于植株生长并增强了其抵抗逆境胁迫的能力,氮素供应不足(0.00~0.50mmol/L)或过量(15.00mmol/L)均不同程度限制了植株的正常生长及生理代谢活动。     

珍稀濒危植物膝柄木种子催芽研究

以采自越南广宁省海河县的膝柄木种子为试材,研究了不同药剂和浓度对种子发芽率和芽苗主根生长的影响。结果表明:与水浸相比,艾比蒂生根剂1号和双吉尔氨基酸肥料6号0.5~15.0mg/L浸种1h,对膝柄木种子发芽均没有促进作用,可见水浸即可有效促进膝柄木种子发芽;艾比蒂生根剂1号0.5mg/L和双吉尔氨基酸肥料6号0.5~10.0mg/L对膝柄木芽苗主根生长有很好的促进作用。