卤虫染色体倍性组成的研究

本文报道了我国4个地理品系卤虫的染色体倍性组成及卵径分布,分析了卤虫染色体的非整倍性,讨论了卤虫种的分布。 天津卤虫有2倍体(2n=42),占33.3％和5倍体,占16.2％;染色体数的波动为21—108;卵径为262±17μm。 海南卤虫有2倍体(2n=42),占8％;4倍体,占17.7％;5倍体,占18.3％;染色体数的波动为16—111;卵径为285±15μm。 新疆卤虫有2倍体(2n=42),占39.2％;染色体数的波动为17—106;卵径为269±15μm。 山西卤虫有2倍体(2n=42),占45.1％,染色体数的波动为17—84;卵径为234±13μm。     

Development of studies on the physiology of the neuroendocrine system at Kiev University

Data on development of studies in the field of physiology of the neuroendocrine system conducted at the Kiev University under the leadership of professor B. G. Novikov are presented. Hypothalamus has been studied for its significance in the control of the endocrine gland function and periodic formogenic processes.     

The Effect of I155T,K156Q,K156E and N186K Mutations in Hemagglutinin on the Virulence and Reproduction of Influenza A/H5N1 Viruses

Molecular Biology - The continued circulation of influenza A virus subtype H5 may cause the emergence of new potential pandemic virus variants, which can be transmitted from person to person. The...     

Sorghum Insect Problems and Management

Sorghum (Sorghum bicolor) has high levels of starch,sugar,and fiber and is one of the most important energy crops in the world.Insect damage is one of the challenges that impacts sorghum biomass production.There are at least 150 insect species that can infest sorghum varieties worldwide.These insects can complete several generations within a growing season,they target various parts of sorghum plants at developmental stages,and they cause significant biomass losses.Genetic research has revealed the existence...     

Methodological features of magnetic resonance imaging mammography

By studying 211 females by currently available radiation techniques, such as X-ray study, ultrasonography, and magnetic resonance imaging mammography (MRIM), the authors consider that the specificity of contrast-enhanced MRIM (CE MRIM) is greater than that of MRIM without administering magnetic resonance contrast agents (MRCA). CE MRIM reveals clinically suspicious early-stage breast lesions and defines the stage of a tumorous process, the patients being unexposed to ionizing irradiation. CE MRIM as an auxiliary technique becomes one of the most informative ones, particularly in girls, early reproductive-age females with developed glandular tissue, and pregnant females. In the authors' opinion, the total algorithm of a breast study in this group of patients in specialized medical centers where trained physicians work should differ from the generally accepted algorithm: instead of applying X-ray mammography (XRM) as a basic method of primary diagnosis, ultrasound mammography using Doppler color mapping, followed by MRIM or XRM should be employed.     

桃儿七光合生理特性的地理差异研究

对中国由南向北5个种源地桃儿七(Sinopodophyllum hexandrum)的光合生理生态特性进行了研究.结果表明:(1)北部宁夏六盘山地区植株的光饱和点(LSP)和光补偿点(LCP)最高,表观光量子效率(AQY)、瞬时光能利用效率(ILUE)和最大光合速率(Pmax)最低,光合能力最差;最南部云南纳帕海植株的LSP和LCP很低,但因其AQY和ILUE最高,故其Pmax最大,强光下的光合能力最高.(2)最南部云南纳帕海和最北部甘肃兴隆山个体的羧化效率(CE)最高,且CO2补偿点(CCP)较低,因此CO2利用率较高;而较南部四川刷经寺个体的CE最低,且CCP最高,故CO2利用效率最低.(3)各种源植株叶片的叶绿素总量及叶绿素a含量无显著差异,而不同地区个体的Chla/Chlb值差异显著,最北部甘肃兴隆山植株的Chla/Chlb值最大,而南部四川刷经寺的Chla/Chlb值最小.(4)各种源地植株的水分利用效率(WUE)和蒸腾速率(Tr)对光量子通量密度(PFD)与CO2浓度的响应过程也表现出显著的地理分异.总的来看,桃儿七是一种喜光但又较耐阴植物,但不同分布区桃儿七的光合生理生态特征已经出现了较显著的地理分化.     

A型肉毒毒素轻链基因的克隆及其结构分析

以献报道的A型肉毒毒素基因全序列为标准,设计并合成一对引物,自肉毒梭菌基因组中扩增出肉毒毒素轻链基因片段,并将扩增产物与pGEM—T载体在体外连接,构建测序重组质粒,进行测序和基因结构分析。PCR扩增获得了产物为1 364bp的DNA片段,测序结果与DNA数据库对照检索分析证明,此基因片段与GenBank中的A型肉毒毒素LC基因的一致性达99．9％以上,可以认为克隆的基因为A型肉毒毒素LC基因。     

Embryogenetic features of the serum protein composition of chicken blood

Protein composition of the blood serum in chick embryos of two breeds and in their hybrids has been investigated by polyacrylamide gel electrophoresis. Significant changes in the proportion of protein components of pre-albumin, albumin and post-albumin zones during prenatal development of chicks were observed. These changes are alleviated in hybrid embryos. The decrease in protein content of post-albumin zone, which contains foetoproteins, takes place to the end of incubation. This decrease is less significant in hybrid chicks as compared to that in the original hen breeds.