Influenza B virus in seals

Influenza B virus is a human pathogen whose origin and possible reservoir in nature are not known. An influenza B virus was isolated from a naturally infected harbor seal (Phoca vitulina) and was found to be infectious to seal kidney cells in vitro. Sequence analyses and serology indicated that influenza virus B/Seal/Netherlands/1/99 is closely related to strains that circulated in humans 4 to 5 years earlier. Retrospective analyses of sera collected from 971 seals showed a prevalence of antibodies to influenza B virus in 2% of the animals after 1995 and in none before 1995. This animal reservoir, harboring influenza B viruses that have circulated in the past, may pose a direct threat to humans.     

Influenza virus purification with the zonal ultracentrifuge

Sufficient amounts of influenza virus (density, 1.185; size, 722S) can be highly purified (22,000 chicken cell agglutinating units per milligram of protein) with a zonal ultracentrifuge, used first in a rate process followed by isopycnic banding, to permit its detailed biological and physical-chemical evaluation.     

Hydrophobic organization of membrane proteins

Membrane-exposed residues are more hydrophobic than buried interior residues in the transmembrane regions of the photosynthetic reaction center from Rhodobacter sphaeroides. This hydrophobic organization is opposite to that of water-soluble proteins. The relative polarities of interior and surface residues of membrane and water soluble proteins are not simply reversed, however. The hydrophobicities of interior residues of both membrane and water-soluble proteins are comparable, whereas the bilayer-exposed residues of membrane proteins are more hydrophobic than the interior residues, and the aqueous-exposed residues of water-soluble proteins are more hydrophilic than the interior residues. A method of sequence analysis is described, based on the periodicity of residue replacement in homologous sequences, that extends conclusions derived from the known atomic structure of the reaction center to the more extensive database of putative transmembrane helical sequences.     

Antibodies to cell membrane antigens associated with human T-cell leukemia virus in patients with AIDS

The acquired immune deficiency syndrome (AIDS), which has recently occurred at increasing rates in homosexual men, intravenous drug users, and others, is characterized by the development of Kaposi's sarcoma and several opportunistic infections including pneumonia caused by Pneumocystis carinii. Serum samples from patients with AIDS and from matched and unmatched control subjects were examined for the presence of antibodies to cell membrane antigens associated with human T-cell leukemia virus. Nineteen of 75 of the AIDS patients had antibodies directed to surface antigens of Hut 102, a reference T lymphoid cell line infected with leukemia virus, as did two of the 336 control subjects.     

环境胁迫下邻羟基苯甲酸对杉木幼苗电导率的影响

通过水培方法,用PEG模拟水分胁迫及1/2 Hoagland培养液、缺钙和缺磷模拟营养胁迫,研究环境因子胁迫下的杉木自毒物质邻羟基苯甲酸对1年生杉木幼苗的毒害作用。结果表明,无论是营养胁迫还是水分胁迫,杉木幼苗的电导率均增加,表明在水分和营养胁迫下邻羟基苯甲酸加深了对杉木幼苗的毒害作用。     

嗜水气单胞菌322A的外膜蛋白及其抗原性

用十二烷基肌氨酸钠抽提结合超速离心的方法提取一株日本鳗鲡致病性嗜水气单胞菌322A和其他4株气单胞菌标准菌株的外膜蛋白(Omp);通过SDS-PAGE分析比较这5株气单胞菌Omp的组成.结果表明,5株气单胞菌的Omp电泳可得到5-13条条带,其分子质量主要集中在20-50 ku之间,且28 ku的Omp为5株气单胞菌所共有.用罗非鱼感染322A全菌后的恢复期血清进行蛋白质印迹试验的结果显示,322A的Omp条带中有4条发生阳性反应,其分子质量分别为28、37、43和45 ku.用兔抗322A Omp的血清进行蛋白质印迹试验的结果显示,322A的Omp条带中有5条发生阳性反应,其分子质量分别为28、33、37、43和45 ku.不同抗血清的印迹结果提示了322A数条主要Omp具有免疫原性,有望成为疫苗研发的候选材料.     

不同方法对酵母细胞膜通透性的影响

通过测定超声处理前后发酵液中核酸、蛋白质及1,6-二磷酸果糖(FDP)浓度的变化,研究了功率超声及有机溶剂对酵母细胞膜通透性的影响．结果表明随着超声作用时间的增加,功率为600、500、400W的处理都使胞内核酸、蛋白质及FDP的渗出浓度逐渐提高,其中,600W超声的作用最为明显．超声处理后,细胞的存活率都逐渐减小,即细胞的破碎程度增大．其中,随着超声作用时间的延长,600W的超声使细胞存活率下降最快．500W超声次之,400W超声使细胞的存活率下降最慢．有机溶剂中,甲苯和氯仿对胞内物质的渗出率影响非常大．但甲苯和氯仿对细胞的损伤非常严重．乙醚对细胞的存活率影响不大．     

Morphologic observations on trachoma virus in cell cultures

When cultures of cells derived from the entoderm of the chick embryo were infected with trachoma virus, cytoplasmic inclusion bodies composed of viral particles were easily demonstrated. The inclusions are similar to those found in stained smears from trachomatous eyes and they developed in a sequence characteristic for this group of viruses. This method of culture appears to offer a valuable additional tool for study of the trachoma agent.     

创伤弧菌外膜蛋白的分离及其抗原性分析

分别采用Sarkosyl和PMSF法分离、提取鳗源创伤弧菌FJ03-X2的外膜蛋白,并应用SDS-PAGE和Western-blotting分析比较两种方法提取的外膜蛋白的组分和抗原性。SDS-PAGE分析结果表明,Sarkosyl法分离的主要外膜蛋白分子量集中在14～66 kDa之间;而PMSF法分离的主要外膜蛋白分子量分布在14～92 kDa之间。在两种方法中,分子量38 kDa、36 kDa的外膜蛋白均为高丰度蛋白。两种方法提取的创伤弧菌外膜蛋白经SDS-PAGE后,用兔抗创伤弧菌FJ03-X2血清进行Western-blotting,结果显示,兔抗FJ03-X2高免血清能识别绝大多数外膜蛋白组分,说明FJ03-X2菌株的外膜蛋白具有良好的抗原性。其中,分子量分别为66kDa、47 kDa、44 kDa、38 kDa、36 kDa、34 kDa的外膜蛋白呈强阳性反应,是主要的免疫原组分。同时,经比较分析认为PMSF法提取创伤弧菌外膜蛋白的效果更好。     

几种病毒抑制剂控制烟草花叶病的试验效果

烟草花叶病(烟草普通花叶病TMV,烟草黄瓜花叶病CMV)是陕西烟区烟叶生产中危害最大的病害,发病烟田不仅造成产量的损失,而且使烟叶质量严重下降.近年来在陕西烟区常年流行发生,平均发病率为15%左右,重病田块达到100%,部分烟田绝收,为此作者对目前生产上应用的几种病毒抑制剂进行了田间药效对比试验.     

棉铃虫不同发育阶段围食膜蛋白的变化分析

以5龄棉铃虫幼虫围食膜蛋白为抗原制备抗体,采用Western blot方法检测了围食膜蛋白在不同发育阶段的存在及变化.结果表明,棉铃虫围食膜蛋白在胚胎期从产卵后1h已经开始表达;在幼虫蜕皮过程中亦有表达,但是蛋白表达的种类和表达量具有明显差异;在蛹及成虫中只少量表达.利用RT-PCR技术,检测了肠粘蛋白HaIIM86在棉铃虫不同发育阶段和5龄幼虫不同组织中的表达情况.结果显示,HaIIM86的分泌表达贯穿于棉铃虫的胚胎期、初孵幼虫期、蛹及成虫期的整个生活周期,并且HaIIM86的表达具有中肠组织特异性.     

吸烟对口腔鳞状上皮细胞膜表面结构的影响

应用原子力显微镜(AFM)对无吸烟史的健康人、中度吸烟组、重度吸烟组、口腔鳞状上皮不典型增生组、口腔鳞状细胞癌组的口腔鳞状上皮细胞膜超微结构进行观察,并应用图像软件分析细胞膜表面的平均粗糙度、峰值、表面积差值,以探讨吸烟对口腔鳞状上皮细胞膜超微结构的影响机制,寻找预测口腔癌发生的早期检测指标.结果表明:随着吸烟指数的增加,细胞外形逐渐不规则,癌细胞异型性较大;细胞膜表面平均粗糙度、峰值、表面积差值呈增大趋势.证明吸烟影响口腔鳞状上皮细胞膜超微结构.     

猪流感病毒研究进展

猪流感是猪常见呼吸道疾病之一,在世界范围内流行.患猪常续发其他疫病,导致猪死亡率增加,该病毒变异体还可跨种传播,严重影响养猪业的发展及人的健康.为此,简要介绍了猪流感的病原,比较了猪流感临床症状,分析了病毒跨种间传播致病机制的分子基础,并概述了其公共卫生意义.     

Excess polymorphisms in genes for membrane proteins in Plasmodium falciparum

The detection of single-nucleotide polymorphisms in pathogenic microorganisms has normally been carried out by trial and error. Here we show that DNA hybridization with high-density oligonucleotide arrays provides rapid and convenient detection of single-nucleotide polymorphisms in Plasmodium falciparum, despite its exceptionally high adenine-thymine (AT) content (82%). A disproportionate number of polymorphisms are found in genes encoding proteins associated with the cell membrane. These genes are targets for only 22% of the oligonucleotide probes but account for 69% of the polymorphisms. Genetic variation is also enriched in subtelomeric regions, which account for 22% of the chromosome but 76% of the polymorphisms.