Pyruvate kinase is necessary for Brucella abortus full virulence in BALB/c mouse

Brucellosis, caused by a facultative intracellular pathogen Brucella, is one of the most prevalent zoonosis worldwide. Host infection relies on several uncanonical virulence factors. A recent research hotpot is the links between carbon metabolism and bacterial virulence. In this study, we found that a carbon metabolism-related pyruvate kinase (Pyk) encoded by pyk gene (locus tag BAB_RS24320) was associated with Brucella virulence. Determination of bacterial growth curves and resistance to environmental stress factors showed that Pyk plays an important role in B. abortus growth, especially under the conditions of nutrition deprivation, and resistance to oxidative stress. Additionally, cell infection assay showed that Pyk is necessary for B. abortus survival and evading fusion with lysosomes within RAW264.7 cells. Moreover, animal experiments exhibited that the Pyk deletion significantly reduced B. abortus virulence in a mouse infection model. Our results elucidated the role of the Pyk in B. abortus virulence and provided information for further investigation of Brucella virulence associated carbon metabolism.     

对动物防疫法中牵连违法行为的适用分析

1牵连违法情形在动物防疫法的存在动物卫生执法是《中华人民共和国动物防疫法》实现的重要途径和有力保障,严格遵守《中华人民共和国     

Development of a disperse dye immunochromatographic test for the detection of antibodies against infectious bursal disease virus

For investigating the feasibility of using disperse dyes as an immunoassay chromogenic marker, a disperse dye, DADISPERSE NAVY BLUE SP, was selected in analyzing antibody against infectious bursal disease virus (anti-IBDV). With the color intensity revealed in the disperse dye immunochromatographic test (DICT) strip as the objective function, the optimal dyeing conditions were found as follows: dye concentration absorbance (at lambda(max)=587nm)=3, pH 7, 50 degrees C, for 10min. Under these conditions, the resultant dyed-antibody (rabbit anti-chicken) can produce an optimal color intensity reading of 55,054 on the strip. For performing qualitative immunoassay, chicken sera samples taken from different farms were used for the anti-IBDV titre assessment. The results of DICT strips showed very high sensitivity and specificity as compared to that analyzed by FlockChek enzyme linked immunosorbent assay (F-ELISA) kits. For quantitative immunoassay, it was found that the color intensity measured with DICT was linearly correlated to that of F-ELISA titre (r(2)=0.9687). Therefore, DICT was further applied to the detection of chicken anti-IBDV sera under vaccination in the farms. The average titres of the sampling groups exhibited a strong agreement to that of F-ELISA. Accordingly, the DICT method developed in this study, shown to be reliable, cheap and simple in both qualitative and quantitative immunoassays, is particularly suitable for point-of-need testing (PONT) in agricultural applications.     

饲用复合酶制剂酶学特性研究

饲用复合酶制剂的主要酶种包括纤维素酶、蛋白酶、脂肪酶和淀粉酶。利用高产菌株S6-5、Y7-6和B5-12混合发酵生产复合酶制剂,发现纤维素酶催化反应最适宜的酸碱度在pH=5.0,反应体系温度为60℃时,纤维素酶活力达到14293U/g;蛋白酶酶活在pH=6.0时酶催化能力最强;而脂肪酶和淀粉酶在50℃时催化能力最强,在60℃催化能力下降,但不明显。     

规模猪场母猪繁殖障碍综合征的病因调查

作者采用9套试剂盒，检测了7种能引起猪繁殖障碍综合征的传染病，对来自有繁殖障碍症状的305场次进行猪瘟(HC)抗原检测，并对包括这305场次在内的978个猪场(次)病例的6346份血清样品及52698份田间血清样品进行HC、猪繁殖与呼吸综合征(PRRS)、伪狂犬病(PR)、日本乙型脑炎(JE)、细小病毒感染(DPV)、猪衣原体病(Chla)、布鲁氏菌病(Bruc)等7种传染病的抗体检测。结果表明，在有繁殖障碍症状的猪场，HC抗原检出率高达61．97％，并且在不使用疫苗的情况下，PR3RS、PR、JE、Chla和PPV的抗体阳性场分别为49．42％、34．29％、12．72％、31．71％、和48．08％。HC和：PR交叉感染率达23．81％；HC和：PRRS交叉感染率为9．52％，PR和PRRS交叉感染率高达59．65％；另外JE、PPV也同HC、PR、PRRS存在部分交叉感染。不使用疫苗的田间血清样品的PRRS、PR的抗体阳性率也高。HC与PRRS．PR、Chla、JE和PPV中的一种或几种混合感染可能是引起繁殖障碍造成严重损失的主要原因。加强综合防制，优化免疫程序、把握引种关、加强生物安全措施是防制猪繁殖障碍综合征的关键。     

家蚕丝质性状选择效果研究

本文采用系统选择、杂交改良等方法。对解舒、净度、强伸力、茧丝长等家蚕主要丝质性状进行了研究。结果表明,解舒、净度、茧丝长系统选择与杂交改良是有效的;对解舒率和茧丝长进行严格综合系统选择,在一定程度上能克服解舒率与茧丝长的负相关关系;系统选择法所建立的解舒好系与解舒差系能稳定遗传;解舒率与强力、伸长度成正相关,但相关程度很低,一代杂种的强力高于原种。     

中国呼伦贝尔草甸草原资源特征

带有寒生性质的线叶菊草原出现在大兴安岭东西两侧山地阳坡和丘陵中上部，贝加尔针茅草原沿着山前丘陵向南分并且总是处于丘陵斜坡和高台地的显域生境，丘陵坡麓，宽谷地和高平原东部发育着羊原草原。三个草原类型都是以多年生草本占绝对优势。中旱生植物居首位，达钨尔－蒙古成分构成群落核心，真具有旱生性特征。群落类型分化多样，在空间分布上形成了明显的生态系列。这三个草原类面积占草甸草原的８８％，其中羊草草原第一性生产     

西藏“一江两河”流域中部草地沙漠化与防治

据１：３．５×１０＾４假彩色红外航空像片室内判读与野外调查，本区沙漠化草地可分为中度及轻度两种，面积１２．８２３万ｈｍ＾２，导致草地沙漠化的人为因素主要是超载过牧，樵柴，放牧制度不合理等，草地沙漠化防治可采取生物，管理及工程等措施。     

3H—萱草根素在小鼠体内吸收分布,排泄和代谢的初步观察

本文应用放射性同位素示综技术,初步观察了~3H-萱草根素在小鼠体内吸收分布、排泄和代谢的全过程。~3H-萱草根素口服后0.5小时,小鼠血液中放射性即达到高峰,并以低浓度维持96小时以上;其随血液循环分布于各组织器官,以胃肠组织含量最高,其次是肝脏和脾脏。萱草根素有蓄积性;一次给药和以同等剂量分次(每天一次,三天)投药后的相同时间,各组织中~3H-萱草根素的含量差异不显著。主要排泄途径是粪便,其次是尿液。经有机溶剂处理后的尿液分为水、脂二相,其放射性测量和薄板层析放射自显影结果均表明:~3H-萱草根素在体内经过代谢后结构发生了变化,从尿液中排出的不是萱草根素原形,而是其代谢产物。     

江苏省菜籽饼粕的抗营养因子含量分析

收集华东省市当家的甘蓝型、白菜和芥菜型油菜籽品种２０个，经１０５℃３０分钟处理，小型６２机冷榨取饼，测定ＯＺＴ．ＩＴＣ，得出甘蓝型高硫葡萄糖苷品种在饼中的总苷量最高９．３６ｍｇ／ｇ，比苷蓝型低硫葡萄糖苷品种含总苷２．９５ｍｇ／Ｇ高出２倍。白菜型平均总苷３．１３ｍｇ／ｇ；芥菜型含３．５６ｍｇ／ｇ。以淮油６号、秦油２号菜籽作破碎或干热与否的前处理比较，总苷量以未破碎、未干热的菜饼最高，分别含９．８２ｍｇ／ｇ、１０．６４ｍｇ／ｇ；破碎又干热的菜饼总苷最低，分别为８．６９、７．０１ｍｇ／ｇ。以宁油７号品种为例用６２型冷榨总苷最高为１０．７７ｍｇ／ｇ，９５型其次５．１４ｍｇ／ｇ，２００型最低２．５５ｍｇ／ｇ。采集本省各地大、中、小型油厂、油坊的菜饼粕２１个样，２００型菜粕总苷为２．８ｍｇ／ｇｃｖ４５％，９５型３．３９ｍｇ／ｇ，ｃｖ３９．６％。２００型与９５型在加工过程中产生游离总苷量接近，分别为０．３８和０．４１ｍｇ／ｇ。由芥子酶或酶水解产生的腈类化合物以２００型的菜粕中含量高，平均含１３１８ｍｇ／ｋｇ，ｃｖ７９．７％；９５型含３１８ｍｇ／ｇｃｖ１３２％，其中３６％样本未检出腈量。菜饼粕单宁平均含０．８２％；植酸平均?