浅谈新疆鹅的保种与利用

<正>新疆鹅原名有伊犁鹅、塔城鹅、灰鹅、飞鹅、雁鹅等,其名称不一,后通过调查,认为属于同种异名,新疆家畜家禽品种志统称为新疆鹅。新疆鹅是我国唯一的一个灰雁驯化品种,属珍稀禽类,是一种很有价值的品种资源。2000年8月被农业部纳入第一批国家级畜禽品种资源保护名录。     

Advance on the Tigecycline Resistance Mechanism

Tigecycline,as a new tetracycline antibiotic,is one of the last lines of defense against carbapenems-producing enterobacter multidrug-resistant infections.In recent years,the emergence of tigecycline-resistant strains has severely restricted the clinical use of tigecycline.It was originally believed that the resistance mechanism of tigecycline was mediated by the efflux pump encoded by the chromosome,which could not lead to drug resistance by horizontal transfer.With the deepening of research,it was found that some efflux pump mutations or high expression on the plasmid could also cause the strain's tigecycline sensitivity to decrease.Recently,it has been reported that the plasmid-mediated tet(X) variant can make the strain highly resistant to tigecycline,and can be spread among different species of bacteria through adaptable plasmids.This article described the prevalence and transmission mechanism of high-level tigecycline resistance gene tet(X) variants by introducing bacterial chromosome-mediated tigecycline resistance mechanisms and plasmid-mediated tigecycline resistance mechanisms,and provided a reasonable explanation for the high-level variant of the tigecycline resistance gene tet(X) in animal-derived strains,aiming to provide reference for relevant scientific researchers and clinical workers.     

DNA分子标记技术在芝麻中的应用

近年来分子标记的快速发展,使其在芝麻中也得到了应用。本文概述了芝麻中常用几种分子标记RAPD、ISSR、SRAP、SSR和AFLP的原理和特点,着重论述了分子标记在芝麻遗传多样性检测和基因定位等方面的应用,并对其在芝麻中的应用前景进行了展望。     

Novel Splice Variants of Bovine Interleukin-1 Receptor-Associated Kinase 2 （IRAK2）

Interleukin-1 receptor-associated kinases （IRAKs） are important signaling elements of the toll-like receptors family, which play a role in innate immune responses by coordinating host defense mechanisms. Presently different isoforms of human and murine IRAK2 molecules are cloned, but there is no report on the sequences and structure of bovine IRAK2 gene. In this study, we cloned the bovine IRAK2 gene by RT-PCR and RACE and discovered that there exist two alternative splicing of bovine IRAK2 genes, IRAK2a and 1RAK2b （GenBank accession no. EU528620 and EU528621）. IRAK2a gene is 2 148 bp coding 622 aa, which contains a death domain （aa 14-94） and a kinase domain （aa 205-440）, but 1RAK2b lacks 147 bp of exon 3 corresponding to 1RAK2a, and codes 386 aa which contains only partly kinase domain.     

中晚熟苹果新品种锦秀红

锦秀红是从苹果品种华冠中选出的早熟浓红色芽变新品种。1996年发现芽变枝,与同果园其他华冠果实相比．芽变枝果实表现为成熟早,果面着片状鲜红色。1997年将其定为芽变单系．代号为Ⅱ-1159。1998年开始进行变异体的高接鉴定。经过连续多年观察．证实其嫁接后无性后代性状稳定,2003年起开始在河南陕县、     

与HEp-2细胞粘附现象相关的大肠杆菌O157基因的发现

将产志贺毒素大肠杆菌O157：H7菌株97094培养于含有不同质量浓度的萘啶酮酸(nalidixie acid，NA)的麦康凯(MacConkey)琼脂平板上，获得对NA有抗性的菌株。用含有自杀性质粒pRT733的供体菌SM10λpir(携带转座子TnphoA)和抗萘啶酮酸的97094菌株做接合试验，使转座子TnphoA转入受体菌97094，经过约200个接合试验，有503个菌株在含有Km、NA、XP的LB琼脂平板上形成蓝色菌落，说明在这些菌株中形成了phoA融合基因,并能表达phoA基因。在这503个Km^r，NA^r变异体中，有6株完全失去了对HEp-2细胞的局灶型粘附(local adherence,LA)现象。对构建的6株大肠杆菌O157 TnphoA变异体，克隆TnphoA及其两侧的大肠杆菌O157 DNA序列，用根据TnphoA融合接点处的phoA的DNA序列设计合成的寡核苷酸引物，对各克隆中TnphoA上游的大肠杆菌O157的DNA片段部分进行测序，测序结果做BLAST搜索，发现有4个变异体的TnphoA插入到已知的大肠杆菌O157紧密素基因eae中，有2个变异体的TnphoA分别插入到eae之外的核苷酸序列中，分别插入到一个功能未知的菌毛分子伴侣基因和一个功能未知的Z4182基因的上游。这项研究表明，除紧密素外，大肠杆菌O157尚有其他因子参与对真核细胞的粘附。     

利用马铃薯茎段离体筛选耐盐变异体

  以4个马铃薯品种的茎段为外植体, 在含不同浓度NaCl的培养基上直接诱导耐盐愈伤组织,筛选耐盐变异体。结果表明, 不同品种的耐盐性有差异, ‘东农303’和‘鄂1号’愈伤组织诱导的最大耐盐浓度为0.8% , ‘费乌瑞它’为0.6% , ‘夏波帝’为0.4%。盐胁迫抑制愈伤组织芽和根的分化, 耐盐愈伤组织继代不宜超过8～10次。盆栽和离体鉴定表明, 筛选出的耐盐变异体保持了耐盐的特性。