黑龙江省玉米大斑病菌生理小种组成变异研究

分别对1997年和2001年黑龙江省玉米主产区的玉米大斑病叶标样分离、鉴定,结果显示1997年只有位于哈尔滨市的省农科院试验地存在有玉米大斑病2号生理小种,2001年2号生理小种已普遍存在。说明玉米大斑病生理小种组成发生了改变。     

不同类型籼粳亚种间杂种F1可利用和非可利用杂种优势的评价和利用

 搜集典型籼粳品种、广亲和品种、偏籼或偏粳品系及恢复系并进行杂交。选取25个籼粳亚种间杂种F1，将其划分为5类。以这5类25个组合的生物产量、茎叶重、秆高、出穗期、每穗颖花数、实粒数、结实率等性状为基本资料，分别计算其超亲优势与竞争优势。结果指出：籼粳亚种间杂种F1茎叶重与结实率存在负相关，杂种优势含可利用与非可利用两部分，典型籼粳F1杂种优势是难以利用的，利用广亲和系与偏籼或偏粳恢复系及其派生系或者偏籼广亲和系和偏粳广亲和系配组，实现部分利用亚种间杂种优势，应作为当前亚种间杂种优势利用育种战略的重要措施。     

提取水稻DNA的一种简易方法

水稻染色体RFLP(DNA限制性片段长度多态性)图谱已经构建,RFLP标记正日益广泛地应用于水稻遗传育种的各项研究中。从水稻植株提取一定数量能被各种限制性内切酶完全酶解的DNA是开展这项研究的第一步。目前抽提水稻DNA的一般方法,如Cornell大学Tanksley博士实验室所用的方法,还是比较复杂,而且要使用氯仿和苯酚来提纯DNA,实验过程中就必须使用耐酚的容器和离心管,这给RFLP工作的广泛开展带来     

乌苏里貉巴氏杆菌的分离鉴定

吉林省松原市某养貉场发生疫病,对病死貉进行剖检,见有典型的巴氏杆菌病的症状,然后对细菌进行分离培养和生化鉴定,证实引起貉死亡的是巴氏杆菌病。     

鹅源副黏病毒的分离鉴定及部分特性研究

采用9日龄鸡胚,从长春某个体养鹅户的病死鹅的肝、脾和肾脏中分离到1株病毒,暂定名为JG04株。经HA和HI试验、电镜观察、常规RT-PCR、NDV荧光RT-PCR检测,证实JG04株为鹅源副黏病毒。与GenBank下载的9株NDV毒株的HN基因作同源性比较,并进一步对JG04株进行耐酸试验、氯仿和乙醚敏感试验、血凝解脱及血凝素热稳定性试验、EID50、ELD50和毒力测定。结果表明:JG04株与江苏近年来分离的鹅源副黏病毒株的HN基因同源性较高,核苷酸同源性高达96.4%,氨基酸同源性高达96.9%;JG04株有良好的血凝性,能凝集人和鸡的红细胞;电镜观察病毒粒子有囊膜,直径约200 nm;对酸、氯仿、乙醚敏感;血凝解脱为快速解脱型,血凝素热稳定性差;EID50、ELD50分别为1.74×109/mL、2.57×109/mL;MDT为54.2 h,ICPI为1.66,IVPI为2.60。上述结果表明,GJ04株与新城疫病毒(NDV)速发型具有类似的毒力,属强毒力毒株。     

鲢肌肉脂肪酸分离方法效果比较及组成特征分析

采用了三种不同方法,即超声波提取法、索氏提取法和氯仿-甲醇法,从鲢(Hypophthalmichys molitrix)肌肉中提取鱼油,继而进行酸性或碱性甲酯化,经气相色谱/质谱联用技术,对其脂肪酸组成特征进行了定性和定量分析。结果显示:鲢肌肉检测出25种脂肪酸,其中包括7种饱和脂肪酸,8种单不饱和脂肪酸和10种多不饱和脂肪酸。获得不饱和脂肪酸含量占总脂肪酸含量分别为41.39%、36.15%、33.55%,可见三种分离方法间存在明显分离效果差异。因此得出石油醚作溶剂的超声波萃取法是提取和分析鱼类脂肪酸较理想的方法。     

Reproductive cycle in reared male common Japanese conger, Conger myriaster

Annual changes in gonadal histology, gonadosomatic index (GSI), and plasma 11-ketotestosterone (11KT) levels were investigated in reared male common Japanese congers, Conger myriaster. Young fish, 20–30 cm in total length and around 20 g in body weight, caught in November 1996 (group 1) and in September 1999 (group 2) were reared for 3 years in seawater at temperatures ranging from 10 to 20 °C.

In most fish, only spermatogonia occupied the testes for 1 year and a few months after capture. Spermatocytes appeared in February, and both spermatids and spermatozoa appeared in March, in 1998 for group 1 and in 2001 for group 2. Spermiation was observed from May to September and reduction in testis was observed after October in both groups. GSI and plasma 11KT levels changed with progression of spermatogenesis. Although GSI was less than 1.0 and the plasma 11KT level less than 1.0 ng/ml, in the first year in most fish, both increased in the second year of rearing. GSI peaked in June 1998 (5.3±3.0; mean±standard deviation) in group 1 and May 2001 (2.3±1.3) in group 2, and bottomed in October (0.3±0.1) in both groups. Plasma 11KT levels peaked in March 1998 (5.8±1.9 ng/ml) in group 1 and May 2001 (4.4±2.4 ng/ml) in group 2, and bottomed in August in group 1 and September in group 2 (around 0.1 ng/ml in both groups). Spermatogenesis and changes in GSI and plasma 11KT levels were repeated the following year in both groups.

These observations indicate that males have an annual reproductive cycle under rearing conditions. It is possible that wild male common Japanese congers also have multiple spawning seasons in their lives.     

林蛙肠道中乳酸菌的分离及鉴定

用2种方法从健康林蛙肠道菌群中分离乳酸菌,并进一步纯化及鉴定.试验结果表明,用乳酸菌半选择性培养基液体培养液先富集后分离得到了11株单一的乳酸杆菌,经过一系列生化鉴定,11株菌为同一种菌即嗜酸乳杆菌.该菌对嗜水气单胞菌具有抑制作用,抑菌圈直径为12 mm.在胆盐含量为0.3%,pH值为3时仍然生长,表明该菌株完全能适应动物胃肠道环境,作为微生态制剂用菌种具有较好的潜力.     

Atlantic halibut (Hippoglossus hippoglossus) vitellogenin: induction,isolation and partial characterization

Vitellogenin (VTG) synthesis was induced by repeated injections of estradiol-17 in juvenile Atlantic halibut (Hippoglossus hippoglossus). VTG eluted as a large, phosphoprotein containing peak on DEAE-Sephacel chromatography of plasma from estradiol-17 treated juvenile and mature female, but not mature male halibut. A purification procedure for Atlantic halibut VTG was developed, where VTG was precipitated with MgCl₂, EDTA and distilled water, and the precipitated protein submitted to anion exchange chromatography on DEAE-Sephacel. Precipitated VTG eluted as a broad, partly dissociated peak on DEAE-Sephacel, when chromatography was run at 4°C, but the protein appeared intact when analysed both by SDS PAGE and native PAGE. DEAE-Sephacel chromatography at room temperature resulted in an irregular elution pattern and a dissociated protein fraction, as analysed by SDS PAGE. Biochemical characterization of VTG showed that the molecular mass of the monomer was ca 160 kDa, as estimated by SDS-PAGE. The total lipid content was 19.8% w/w, with 64%, or 12.7% of the total weight, as phospholipid. Protein bound phosphorus constituted 0.62% w/w of halibut VTG. Plasma dilution curves from mature and maturing female halibut were parallel with a dilution curve from halibut egg yolk homogenate in an homologous RIA. Plasma from mature male, but not juvenile halibut crossreacted with the VTG antiserum.