微重力环境下的细菌生物学效应

本文主要根据国内外微重力环境下细菌生物学效应的研究文献,从细菌生长繁殖、抗生素敏感性、毒力变化、新陈代谢等方面进行总结,并概述了微重力环境改变细菌生物学性状的作用机制,展望了微重力环境细菌生物学技术的未来发展。     

植物对环境应力刺激的生物学效应

植物生长在自然环境中由于其“不动性”而不可避免地要受到各种环境应力的刺激,应力－生长关系一直是生物学家和物理学家所关心的课题,是生物力学的灵魂。很多研究已经表明外界应力作用对植物的生长发育有着重要的影响。本综述了国内外关于应力对植物组织所引起的生物学效应,首先论述了环境应力所引起的宏观生物学效应,随后重点论述了环境应力所引起的生物学效应在细胞和分子水平上的研究,其中包括单个细胞的加载、电磁场、微     

内皮素的生物学效应

内皮素(endothelin,ET)是1988年日本Yanagisawa 等从猪的主动脉内皮细胞中分离纯化出的一种由21个氨基酸组成的血管活性多肽,主要分布于肾、肺、肝、心、脑、主动脉和静脉等血管内皮细胞中,其中肾脏含量最高(52. 0pg/mg 蛋白)。近年来的研究证明,它不仅是血管内皮细胞所产生的局部或循环激素,而且也可作为一种神经介质,广泛分布在一些中枢神经系统的神经元内,其中以桥延脑--心血管调节中枢的含量最高,其含量可达43. 8pg/mg 蛋白,可参与机体多种生理功能的     

一氧化氮的生物学效应

一氧化氮是新近发现的一种重要的细胞内信使和神经介质,它在免疫系统、心血管系统、神经系统等的调节中起着重要的作用。ＮＯ功能的研究为生物学的许多领域提供新的认识。     

心钠素的生物学效应

心钠素的生物学效应刘桂萍（吉林省白城高等师范专科学校生物系,１３７０００）付晶（吉林省长春市宽城区中医院,１３００５１）心钠素（ＡＮＰ）是８０年代初由加拿大,美国及日本学者先后从人及大鼠的心房肌细胞中分离纯化出的一种循环激素。它具有强大的利钠、利尿、...     

铜-毒死蜱对蚯蚓的联合毒性效应

为了揭示当前我国土壤环境中污染严重的代表性重金属铜和有机磷农药毒死蜱联合作用的毒性效应及风险,本研究以赤子爱胜蚓为模式生物,分别应用人工土壤法和滤纸法探讨铜、毒死蜱单一及复合暴露对蚯蚓生长及抗氧化防御系统的影响.结果表明: 随着铜、毒死蜱单一暴露浓度的增大,人工土壤法蚯蚓体质量增长率趋于降低;二者复合暴露组蚯蚓体质量变化则相对平缓.采用概率相加法求得不同浓度组合铜、毒死蜱对蚯蚓体质量联合作用的q值均小于0.55,表明二者的联合作用类型为显著拮抗作用.滤纸法铜、毒死蜱对蚯蚓过氧化氢酶、超氧化物歧化酶活性的联合作用类型主要为拮抗作用;而对还原型谷胱甘肽和丙二醛含量的影响表现为低浓度协同而高浓度拮抗的作用类型.     

巴氏新小绥螨毒死蜱抗性选育及生物学特性

[目的]明确巴氏新小绥螨Neoseiulus barkeri毒死蜱抗性对其生物学特性的影响,为抗药性捕食螨田间应用提供理论基础.[方法]在室内采用药膜法测定毒死蜱对巴氏新小绥螨的毒力,以半致死浓度(lethal medium concentration,LC50)为选择压力,对巴氏新小绥螨敏感种群进行逐代汰选.应用生命...     

生长激素生物学效应的研究进展

人类生长激素(growthhormone,GH)最先作为替代疗法用于治疗儿童GH缺乏性侏儒症,后来的研究表明,它具有明显的节氮效应,因而广泛用于烧伤、感染及严重创伤,并取得了良好疗效.此后,进一步研究表明GH能促进胰岛素样生长因子(IGF)的形成进而促进骨折愈合,使其应用范围进一步扩大.本文就生长激素生物学效应进行综述.     

激光的生物学效应研究

本文通过分析多种激光（十五种激光器,波长从２６６ｎｍ—４４７．２×ｌ０３ｎｍ）对生物体（九十多种生物,如果把品种计算在内,则大约２００多种）的生物学效应研究发现：①不同波长激光都能对生物体产生作用;②激光对动物、植物、微生物均能产生生物学效应;③低剂量辐照对生物体主要是刺激作用,随着剂量增加则产生抑制、损伤,以及诱变和致死作用;④激光对６０Ｃｏ—γ射线的辐射损伤有一定的修复作用;⑤低功率激光对生物体的作用主要在于其电效应和电磁场效应（关于这个方面,将另文详细讨论）。     

激光生物学效应的研究

本文较系统地报道了CO_2激光,He-Ne激光的生物学作用,证明激光确能导致生物体内生理生化的变化,确能诱发染色体畸变和基因突变。作者认为激光作为育种上一种新的诱变因素是有根据的。     

环境胁迫与生物防御反应

生物的生存总是逃避不了周围各种环境胁迫因素的影响。非生物因素如温度、水分、湿度、光照、营养、环境污染、物理干扰和土壤坚实度等;生物因素如有害生物的袭击等。兴衰存亡的关键,除了取决于胁迫的种类、强度     

International Society for Biological and Environmental Repositories

Genetically altered mice are an important tool for biomedical research. Several transgenic mice have been created in which activation of the transgene results in production of β-galactosidase that can be detected by histological means. While preservation and subsequent visualization of enzyme activity in soft tissues can be complicated, it is particularly difficult in bone specimens, especially those that have been decalcified. For these studies, we examined the bones of parathyroid hormone-related peptide (PTHrP) knock-in mice in which expression of PTHrP resulted in β-galactosidase production. During the past decade, several studies have demonstrated the importance of PTHrP in bone. Thus, it is important to preserve and detect β-galactosidase enzymatic activity in bone for these studies. We demonstrate here that β-galactosidase was visualized better in slides with bone sections taken from PTHrP knock-in mice when bones were frozen and sectioned compared to bones that were embedded in plastic and sectioned using a microtome. Importantly, we were able to visualize β-galactosidase in plastic embedded bones when specimens were fixed, stained (X-gal), embedded in plastic, and then sectioned rather than being fixed, embedded in plastic, sectioned, then stained.     

细胞珠蛋白的结构及其生物学效应

细胞珠蛋白(cytoglobin,Cygb)是最近发现的脊椎动物珠蛋白超家族的一员,在体内分布广泛。人Cygb基因定位于染色体17q25,含有4个外显子和3个内含子,编码190个氨基酸残基(分子量20.9kD)。Cygb拥有经典的“three-over-three”α螺旋三明治折叠结构,同神经珠蛋白(Ngb)一样,Cygb血红素在缺乏外源性配体时呈“六配位”结构。Cygb的确切功能尚不十分清楚,目前主要有携氧与储氧、氧感受器、活性氧基团和NO的清道夫、NADH氧化酶或过氧化氢酶样作用和参与胶原形成等假说。     

Effects of Soil pH on the Biodegradation of Chlorpyrifos and Isolation of a Chlorpyrifos-Degrading Bacterium

We examined the role of microorganisms in the degradation of the organophosphate insecticide chlorpyrifos in soils from the United Kingdom and Australia. The kinetics of degradation in five United Kingdom soils varying in pH from 4.7 to 8.4 suggested that dissipation of chlorpyrifos was mediated by the cometabolic activities of the soil microorganisms. Repeated application of chlorpyrifos to these soils did not result in the development of a microbial population with an enhanced ability to degrade the pesticide. A robust bacterial population that utilized chlorpyrifos as a source of carbon was detected in an Australian soil. The enhanced ability to degrade chlorpyrifos in the Australian soil was successfully transferred to the five United Kingdom soils. Only soils with a pH of ≥6.7 were able to maintain this degrading ability 90 days after inoculation. Transfer and proliferation of degrading microorganisms from the Australian soil to the United Kingdom soils was monitored by molecular fingerprinting of bacterial 16S rRNA genes by PCR-denaturing gradient gel electrophoresis (DGGE). Two bands were found to be associated with enhanced degradation of chlorpyrifos. Band 1 had sequence similarity to enterics and their relatives, while band 2 had sequence similarity to strains of Pseudomonas. Liquid enrichment culture using the Australian soil as the source of the inoculum led to the isolation of a chlorpyrifos-degrading bacterium. This strain had a 16S rRNA gene with a sequence identical to that of band 1 in the DGGE profile of the Australian soil. DNA probing indicated that genes similar to known organophosphate-degrading (opd) genes were present in the United Kingdom soils. However, no DNA hybridization signal was detected for the Australian soil or the isolated degrader. This indicates that unrelated genes were present in both the Australian soil and the chlorpyrifos-degrading isolate. These results are consistent with our observations that degradation of chlorpyrifos in these systems was unusual, as it was growth linked and involved complete mineralization. As the 16S rRNA gene of the isolate matched a visible DGGE band from the Australian soil, the isolate is likely to be both prominent and involved in the degradation of chlorpyrifos in this soil.     

一株毒死蜱降解新菌株Sphingopyxis terrae R17的分离鉴定及降解特性

从农药厂排污沟污泥中分离到一株能降解毒死蜱的新菌株,命名为R17,经生理生化和16S rDNA序列同源性分析,鉴定为Sphingopyxis terrae.R17可以利用毒死蜱作为唯一碳源生长,该菌株的最适生长温度为35℃、最适pH为7～8,在此条件下培养28 h后,菌落浓度达9.18×108cfu/mL.研究了该菌在...