我国南方猪高热病的研究(Ⅰ)——大肠杆菌的分离、鉴定和致病性测定

从湖南3个高热病发病猪场11头病死猪的病料组织中均分离出了大肠杆菌,经血清学鉴定,鞭毛抗原(K88、K99、987P和F41)全为阴性反应。经过157种菌体抗原血清学检测,血清型为5、6、15、22、32和83型。药物敏感试验结果表明,分离的大肠杆菌对大多数常用药物耐药,对氟喹诺酮和头孢类药物敏感。将其中4头猪原代分离的大肠菌培养物以原倍(2×107个/mL)、104和108稀释的菌液分别感染18~22 g小白鼠,原倍菌液感染的小白鼠12/30在感染后24 h内出现死亡,而104和108稀释菌液感染的小白鼠均健活;将未经除菌的病死猪组织悬液、过滤除菌的组织悬液、大肠杆菌、过滤除菌的组织悬液及大肠杆菌分别感染30日龄左右的健康小猪,除未经除菌的组织悬液感染猪3/3发病,2/3死亡外,其余所有感染猪只出现体温升高,升幅达1~2℃,减食,精神萎靡,但没有死亡;将死亡猪再次分离到的大肠杆菌感染小白鼠和猪,小白鼠12/15出现死亡,感染猪只出现体温升高(超过1℃),没有出现死亡。结果证明:大肠杆菌在高热病的发病过程中只起协同诱发作用,引起猪发病死亡的真正原因可能是病毒感染。     

丁酸梭菌对肠道上皮细胞黏附及对鳗弧菌抑制的研究

本试验以鱼肠道上皮细胞为模型,以肠道的致病鳗弧菌为对照,研究了丁酸梭菌对鱼肠道上皮细胞的黏附作用及黏附对细胞的损伤和成活率的影响。结果表明∶丁酸梭菌对鱼的肠道上皮的黏附率为7.39±1.85,低于鳗弧菌的黏附率(P<0.05);对细胞的损伤率为1.02±0.35,显著低于鳗弧菌对细胞的损伤率(P<0.05);黏附后丁酸梭菌组对细胞的成活率的影响与正常对照组比较,差异不显著;当酪酸菌、鳗弧菌与肠道上皮细胞共同培养时,使鳗弧菌的黏附率下降7.03%(P<0.05)。因此,该株丁酸梭菌可以安全地黏附鱼肠道上皮细胞,并能有效抑制鳗弧菌的黏附。     

蛹虫草人工栽培条件优化研究

蛹虫草是一种珍贵的药食同源大型真菌．其市场需求日益增加。为加强蛹虫草的人工栽培．从料水比、菌种浓度、接种量和暗培养时间等4个因素进行正交试验．发现接种量（15、20、25mL／瓶）和菌种浓度（6、11、15个／mL）起着重要的作用，而料水比（1：1、1：1．2、1：1．5）和暗培养时间（2、3、4d）作用较小，并优化出高产培养条件．即料水比1：1．5、菌种浓度15个／mL．接种量25mL／瓶和暗培养时间为3d。在此优化条件下．每20g大米能生产出高达17．96g鲜子实体。     

桦褐孔菌多糖的体外抗氧化作用研究

Inonotus obliquusis placed in theBasidiomycotina, Hymenomycetes , Aphyllophoralesand Polyporaceae[1]. The mushroomis a wood-decaying fungus that grows under the bark oflive standing trees such as birch, el m andJapanese alder , or on the dry trunks of thesetrees after felling . In Russian folklore ,I .obliquusis considered a medicinal fungus andhas been widely used to prevent and treatdiseases and tumors affecting the digestivesystem ( e . g . gastric , intestinal and livercancers ) , cardio…     

Effects of mitochondrial ATP-sensitive potassium channel opener and hypoxic preconditioning on the hyperpolarization-activated current of sinoatrial node cells in neonatal rats

AIM: To compare the effects of hypoxic preconditioning (HP) and mitochondrial ATP-sensitive potassium (K_ATP) channel opener pretreatment on the hyperpolarization-activated current (I_f) in sinoatrial node cells.METHODS: Sinoatrial node cells were randomized to five groups: ① Control;②Hypoxia/reoxygenation (H/R);③ HP;④ Diazoxide (mitochondrial K_ATP channel opener)+H/R;⑤ 5-HD (mitochondrial K_ATP channel blocker)+HP.At the end of the experiment, I_f was recorded by whole-cell patch clamp technology.RESULTS: ①H/R significantly enhanced the current densities of I_f, shifted the current activation curve to more positive value by changing the half-activation voltage from (-98.9±2.4)mV to (-85.2±2.5) mV (P＜0.01).② Both diazoxide pretreatment and HP remarkably reduced the augmented current density caused by H/R and shifted the current activation curve to more negative value by changing the half-activation voltage to (-90.7±5.0) mV (P＜0.01) and (-92.2±1.9) mV (P＜0.01).③ 5-HD pretreatment blocked the effects of HP and reversed the half-activation voltage to (-86.3±2.7) mV (P＜0.01).CONCLUSION: The study demonstrates that both mitochondrial K_ATP channel opener pretreatment and HP make current density and kinetics of I_f to approach normal level and to maintain electrophysiological stability of sinoatrial node cells during H/R.     

Influence of ovariectomy and estrogen replacement on gene expression profile of myocardium in rats

AIM:To investigate the influence of ovariectomy and estrogen replacement treatment on profile of gene expression in myocardium by cDNA microarray,and to characterize the targeting genes of estrogen.METHODS:cDNA microarray containing 1 400 rat cDNAs was used to study the genes differentially expressed in myocardium between sham (Ⅰ),ovariectomy (Ⅱ,OVX) and estrogen replacement treatment (Ⅲ,OVX+E2) group.Then down-regulated genes in myocardium of OVX rats were further confirmed by RT-PCR.RESULTS:177 genes were differentially expressed in myocardium between sham and OVX rats,with 91 genes up-regulated and 86 genes down-regulated in OVX rats.164 genes were differentially expressed in myocardium between OVX and OVX+E2 rats,with 113 genes up-regulated and 54 genes down-regulated in OVX rats.There were 54 genes differentially expressed in OVX compared to sham and OVX+E2.They are involved in membrane channels and transporters (18),cell receptors (9),intracellular transducers/effectors/modulator (7) and metabolism (6).Most of the genes (45) were down-regulated in OVX rats and up-regulated in OVX+E2 rats.RT-PCR test confirmed the results of cDNA microarray.CONCLUSIONS:Long-term estrogen replacement may influence the expression of genes involved in membrane channels and transporters,cell receptors,intracellular transducers/effectors/ modulator and metabolism.Long-term estrogen replacement has some beneficial effects on ionic concentration and cardiac function which partially comes from the results of influence of expression on Na+,K+-ATPase and Na+/H+ exchanger.Estrogen has an inhibitory effect on the expression of dopamine receptor,which partially clarify the myocardial protection of estrogen.     

云南主要烟区烟蚜种群解毒酶活力比较

通过测定烟蚜Myzus persicae(Sulzer)的α-NA羧酸酯酶、β-NA羧酸酯酶、谷胱甘肽转移酶和乙酰胆碱酯酶的活力,比较了云南5个主要烟区田间烟蚜种群的4种酶的活力频率分布,结果表明,云南5个烟区的烟蚜田间种群的α-NA羧酸酯酶、β-NA羧酸酯酶和乙酰胆碱酯酶的高活力个体均以楚雄和昆明种群较高,昭通种群和丽江种群较低。谷胱甘肽转移酶在5个烟区烟蚜种群间差异不大。     

燕山板栗种质资源遗传多样性的RAPD分析

为研究燕山板栗的遗传多样性,采用随机扩增多态DNA(randomamplifiedpolymorphicDNA,RAPD)技术对36份燕山板栗种质进行了分析。分析了燕山板栗的遗传丰富度,并对包括36个燕山板栗品种和8份外来板栗品种在内的44份板栗种质进行聚类分析。结果表明,RAPD能有效地区分品种间的差异,用16个随机引物经PCR扩增共得到132个片段,其中有83个多态性片段,占62.9%;不同遗传位点之间遗传多样度最大可达0.444,最小值为0.096,平均多样度为0.187;UPGMA法聚类,将44份板栗种质聚成4个大的类群,36份燕山板栗可分为3个大的类群,外来种质聚为一类。燕山板栗明显不同于外来品种。在RAPD图谱中,找到了19个品种(类型)的特异性标记和标记组合,可作为品种(类型)分子鉴别的依据。     

猪2型圆环病毒Cap蛋白在伪狂犬病病毒中的表达

用EcoR Ⅰ酶切伪狂犬病病毒疫苗株Tk-/gE-/LacZ 基因组,与含有猪2型圆环病毒(PCV2)ORF2基因的重组转移载体pIEORF2共转染IBRS-2细胞.收集病变细胞,经空斑纯化和PCR鉴定,获得了新的重组病毒Tk-/gE-/ORF2 .用Southern blot杂交证明该重组病毒构建正确,用间接免疫荧光法和Western blot证日月该重组病毒可表达PCV2的主要免疫原性蛋白Cap蛋白.重组病毒在IBRS-2细胞上连续传15代后,遗传稳定.该重组病毒在IBRS-2细胞上增殖滴度为10-7.1 TCID50/0.1mL,在鸡胚成纤维细胞上增殖滴度为10-4.8 TCID50/0.1mL,在Marc-145细胞上增殖滴度为10-6.8 TCID50/0.1mL.     

猪精子α-L-岩藻糖苷酶活性定位及其在精-卵结合及受精中的作用

本试验旨在证明猪精子中α-L-岩藻糖苷酶的存在及其在受精中的作用.猪精子α-L-岩藻糖苷酶活性用分光光度计405nm波长测定,并在受精液中添加α-L-岩藻糖苷酶特异抑制因子(deoxyfuconojirimycin hydrochloride,DFM-H)或特异单糖(L-岩藻糖)来检测时该酶活性的影响.结果显示,猪精子含有明显的α-L-岩藻糖苷酶活性.当精子用10μmol/L钙离子载体A23187处理1h后,有70%精子发生顶体反应和72%的酶活性被释放.体外受精液中添加250μmol/L DFM-H或30mmol/L,L-岩藻糖,可分别抑制66%或63%的精子α-L-岩藻糖苷酶活性,并相应抑制37%或36%的透明带表面精子结合数及56%或67%的精子侵入卵数.这些结果证明,猪精子α-L-岩藻糖苷酶主要分布于精子顶体中,特异地作用于透明带寡糖链中的α-L-岩藻糖残基,而参与精子穿入透明带的过程.