Physiological properties and classification of strains of Treponema sp. isolated from pigs in poland

Fifty-one treponemas were isolated from pigs. Twenty-three isolates with typical morphology and growth characteristic were beta hemolytic, enteropathogenic, produced indole and with exception of three strains did not ferment fructose. These strains were classified as typical T. hyodysenteriae and were usually isolated from pigs with symptoms of mucohemorrhagic diarrhoea. The seventeen other isolates were weakly beta hemolytic after 48 h incubation, enteropathogenic, 12 out of 17 produced indole, 10 out 17 fermented fructose. These strains were usually isolated from pigs with symptoms of gray-green diarrhoea and classified as T. hyodysenteriae 2 biotype or intermediate type. They may be compared with Treponema sp. isolated by Taylor et al. Eleven non enteropathogenic strains showed typical characteristic for T. innocens. Gas chromatography analysis of the fatty acids production from glucose, showed that all isolated treponemas produced acetate and butyrate. Typical T. hyodysenteriae produced additionally propionate. Strains of T. hyodysenteriae biotype 2 produced propionate or isobutyrate as well.     

Relationships between Longevity and Linear Type Traits in Holstein Cattle Population of Southern Africa

Relationships between longevity and linear type traits were estimated using data on 34,201 cows with lifetime information and linear type scores. The longevity trait considered was the number of lactations initiated and the linear type traits were rump height, body depth, angularity, rear udder height, fore udder attachment, udder depth, fore teat placement and fore teat length. Fixed effects included in the models were herd year, season of calving and herd-date of classification-classifier and days in milk. Age at first calving and age at classification were included as linear and quadratic covariates. Heritability estimates were low for longevity and moderate for most type traits except rump height and fore teat length. All the phenotypic correlations between longevity and the linear type traits were slightly positive (0.01 to 0.09) except the relationships with rump height and fore teat length which were -0.01 and -0.02, respectively. Genetic correlations between longevity and udder traits as well as angularity were moderate to high and positive (0.22 to 0.48). The only notable negative genetic correlations were longevity with body depth and fore teat length (-0.15 and -0.07, respectively). The genetic correlations suggest that selection for udder traits and angularity should improve longevity in the Holstein cattle population.     

福建省辣椒疫霉菌群体结构表型特征分析

为了明确福建省辣椒疫霉菌群体遗传结构的表型特征,对分离自福建省15个市(县)的300株辣椒疫霉菌的交配型、甲霜灵敏感性及生理小种进行了测定。结果显示,288株为A2交配型,12株为A1交配型,出现频率分别为96%和4%,以A2占优势,在各采集点均有分布。263株对甲霜灵表现敏感,28株为中间型,9株为抗性,分别占总体的87.67%、9.33%和3.00%,甲霜灵敏感菌株为主要菌系。根据菌株对辣椒疫霉菌生理小种鉴别寄主的致病性测定结果,可将辣椒疫霉菌划分为3个生理小种,其中168株为小种3,126株为小种2,6株为小种1,分别占56%、42%和2%,小种3为福建辣椒疫霉菌优势小种。     

内蒙古高温酷暑天气时空分布特征及成因分析

应用1971～2008年内蒙古自治区117个观测站资料,选取64次较强高温酷暑天气过程,结合同期的NCEP再分析资料,应用统计分析和诊断分析方法,对内蒙古高温酷暑天气的时空分布特征及成因进行了分析。结果表明:内蒙古高温酷暑天气地域差异大,高温中心在阿拉善盟沙漠地区的拐子湖,年平均35℃高温日数达32天,也是全国的高温区之一;高温酷暑年日数有增长趋势,影响在增强;高温酷暑集中出现在盛夏季节6～8月,7月发生最多,占一半以上;最高温度出现在每日的14至17时,气温日较差大;高温酷暑天气可分为蒙古暖脊型、贝加尔湖高压坝型、副高西进型、乌拉尔山高脊型四个天气学类型,大陆暖高压脊的强烈发展和维持与高温酷暑天气密切相关;300hPa高空锋区的北退或断裂与大陆暖高压系统的形成和发展有很好的相关性;对流层中层的暖平流对大陆暖高压系统的发展强盛起到关键作用;500～850hPa厚度场可以更好的反映出整层气柱冷暖性质,其分布特征直接影响到内蒙古高温酷暑天气发生的部位和区域;蒙古暖高压控制区中盛行下沉气流,使得大气下沉增温,对流层中低层维持暖心结构,由于整层气柱很暖,低层减压形成了近地层的热低压,具有干热的特征。     

福建省建阳市水稻常见矮缩病的类型与防治

概述福建省建阳市水稻生产上常见的水稻矮缩病类型与防治方法,对建阳市水稻矮缩病的类型辨别、症状特点、流行过程、传播媒介、防治方法做了对比,对防治水稻矮缩病起到一定指导作用。     

高空探测气象系统数据类型分析

根据气象业务现状,通过对高空探测的数据特点进行了较为系统地分析。气象测报工作是随气象工程业务需要而进行的,它是气象工程的保证。由于高空资料的获得和积累,高空气象资料在气象工作中尤为重要。它对反映天气的变化趋势,分析高空气候特点、规律起着举足轻重的作用为气象(候)研究工作及其应用提供了良好的发展前景。     

查尔酮合酶蛋白表达技术、结构、活性和进化

查尔酮合酶(CHS)是类黄酮途径的首步关键酶,参与合成所有类黄酮和异黄酮物质,参与决定多种植物重要性状。NCBI已有2917条CHS序列登录和释放。单个物种基因组中的CHS普遍由基因家族编码,通过基因加倍而产生。CHS蛋白的表达技术目前均是基于大肠杆菌的原核表达,多采用Novagen公司的pET载体系统,最通行参数为37℃条件下1 mmol/L IPTG诱导3h,表达蛋白普遍采用His-Tag进行亲和纯化,采用质谱或免疫分析技术进行身份检测,通过对生化反应底物和产物的HPLC检测可以精确分析酶活。苜蓿等植物的CHS蛋白已完成X射线晶体衍射研究,获得了三维结构和活性位点构象的初步解析,并与植物Ⅲ型PKS超家族中的其它酶类进行了比较。CHS蛋白的催化活性中心含有一个Cys-His-Asn三联体,另外CoA结合通道和内部的起始/延伸/环化腔关系到CHS蛋白的底物特异性及聚酮化合物链延伸的长度。植物Ⅲ型PKS超家族中,其它酶的结构骨架和催化方式与CHS相似,但活性位点残基的变化可能会造成活性中心结构的改变,进而产生底物特异性、催化能力和产物种类的显著变化,是蛋白水平进化的根本动力。     

不同土壤类型对花生(Arachis hypogaea L.)籽实镉积累特性的影响

为了在不同土壤环境下选育出低镉(Cd)积累型花生品种以提高花生品质,以‘白沙1016号’品种花生(Arachis hypogaea L.)为供试作物,棕壤和潮土为供试土壤,采用盆栽试验的方法,研究了2种类型土壤对花生籽实Cd积累特性的影响。结果表明：2种类型土壤条件下的花生籽实生物量差异显著（P<0.05）;在供试土壤Cd处理范围内(≤10.0 mg/kg),籽实生物量均随2种土壤Cd处理浓度增加呈“低促高抑”现象。花生籽实对土壤Cd的生物富集系数均随2种土壤Cd处理增加呈显著降低趋势（P<0.05）,且土壤类型间差异不显著。花生籽实Cd含量和Cd生物富集量均随2种土壤Cd处理的增加而显著增加（P<0.05）,但两者在棕壤介质中均显著大于潮土（P<0.05）。土壤类型对花生籽实Cd积累差异的影响主要体现在籽实Cd含量和生物富集量方面。而土壤pH、氧化还原电位(Eh)等均是影响籽实对Cd积累差异的重要因素。     

“探究式”综合设计性实验的开发设计及实践——以“赖氨酸的发酵生产”专业实验为例

以"赖氨酸的发酵生产"专业实验为例,分析了实验教学中存在的问题,阐述了"探究式"综合设计性实验的开发设计及组织实施。     

4种林分类型空气负离子浓度日变化规律

通过对COM-3200PRO空气离子检测仪数据接收方式的改造,使得数据监测与接收空间分离,实现了野外试验24 h不间断的监测。主要监测了杨树林、白蜡林、核桃林、侧柏林4种河南省常见林分类型的空气负离子浓度日变化规律,结果表明,4种林分类型均表现出了相同的日变化规律,即最低值出现在日出前,最高值出现在14:00左右,4种林分类型空气负离子浓度日均值差异明显,其大小排序为杨树林>白蜡林>侧柏林>核桃林。