高温单孢菌属分类研究进展

自从Henssen于1957年建立高温单孢菌属至今,高温单孢菌属各菌种的分类地位一直处于不断的变化之中。近年来,随着该属一些种的重新分类以及新种的发现,高温单孢菌属的分类发生了很大的变化。这主要是由于分类手段已由传统的形态学分类方法向现代的多相分类方法过渡。介绍了自高温单孢菌属建立以来,该属分类的研究现状,认为高温单孢菌属在系统分类上尚需进一步的研究。     

一种产糖化酶高温菌的初筛方法

在中温菌中筛选糖化酶产生菌已有成熟的方法,可是在高温菌中筛选糖化酶产生菌,国内尚无方法介绍。我们采用O-TB试剂法进行高温糖化酶产生菌的初筛,获得满意结果,现简述于后。     

高温菌生物学特性的应用

高温菌是一个热点研究领域。这一领域不断发现新的苗种及特性。高温菌广泛地存在于自然界中,它与常温菌相比有着许多不同的特性。例如,其酶在高温下的稳定性,为化工应用提供了便利。简要介绍了高温微生物已有的应用领域,为进一步的研究工作提供参考。     

高温放线菌的多样性

高温微生物能在高温环境下生存,并能维持其自身生理生化过程的酶系和化合物的稳定性[1].自1969年发现水生栖热菌(Thermus aquaticus)以后[2],高温菌就引起微生物学家的极大关注.高温菌两个显著的特点决定了其在现代分子生物学和工业应用上的重要价值:一是热稳定性功能分子;二是生长极快且会自溶,能在高温条件下发酵而不易受污染.     

不同虫源和致害性的褐飞虱体内共生菌的种群动态

通过对不同地理种群和致害性的褐飞虱体内共生菌,在高温和抗性水稻品种作用下的种群动态研究表明,在正常湿度下褐飞虱体内共生菌的数量随若虫的生长发育而增加,5龄若虫期是共生菌增长的关键期;同一种群的褐飞虱秋季共生菌数量明显高于夏季。广西田间种群的短翅雌虫体内的共生菌数量显高于浙江省的杭州和龙游种群,经高温处理后,3个生物开共生菌数量均显减少,但其子代共生菌的数量在正常温度下马上恢复,与未经高温处理的褐飞虱共生菌数量基本相同,取食抗性品种的生物型1和田间种群的褐飞虱体内的共生菌数量均明显减少,取食抗性品种的第2代的共生菌又均比第1代少。这说明高温对共生菌的影响是暂的,而抗性品种的对共生菌的作用与褐飞虱种群对品种的适应性有关。     

超高温菌酶构象的刚性和热稳定性的相互关系

超高温菌酶具有优良的高温热稳定性,其酶蛋白结构中的氢键、离子对、盐桥和极化表面面积等均高于中温酶,有利于增强其构象的刚性,从而增加其热稳定性。超高温菌酶在中温时比它们的中温同系物更具有刚性,并且刚性是超高温菌酶在高温环境下保持其热稳定性的先决条件。     

保山地区碱性温泉中的高温菌

保山地区位于云南省西部,是全省温泉分布比较密集的地区之一。温泉作为地热资源已引起有关部门的重视,70年代已进行了地热资源的调查和开发利用研究。但是对于温泉中潜在的高温菌资源,尚未进行过系统考察、研究。现将我们对于保山地区pH8.0以上的高温温泉中的高温菌研究结果报告于后。       

温泉高温菌菌种保藏方法的比较*

本文报道用砂土管、冻干安瓿、薄膜和矿油斜面四种保藏方法,分别在室温和冰箱(4℃左右)两种温度条件下保藏温泉高温菌菌种的效果。共保藏419株(其中芽孢菌392株,非芽孢菌27株),保存期为4—7年。结果表明,对于高温菌(特别是嗜热性芽孢杆菌)而言,用砂土管和矿油斜面在室温条件下保藏是经济简便行之有效的方法之一。     

高温菌的细胞壁和细胞被膜

众所周知,细胞壁是生物从非细胞进化到细胞形态之后最早的生化进化指标之一,也是生命三域（ＴｈｒｅｅＤｅｍａｉｎｓ）相互区分的重要特征之一。那么高温菌（Ｔｈｅｒｍｏｐｈｉｌｅｓ）的细胞壁和细胞被膜有什么特征呢？本文对此试作评述。回细菌界高温菌的细胞壁ｌ’－。１１．ｌ＄兰氏阳性高温菌的细胞壁现在资料表明,绝大多数革兰氏阳性高温菌的细胞壁是由ｈ卜乙酸氨基葡萄糖和Ｎ．乙酞胞壁酸通过［６,－ｌ,４］糖昔链联接成的聚糖链、Ｌ一丙氨酸一Ｄ一谷氨酸一Ｄ～Ｌ丙氨酸一（Ｄ一两氨酸）组成的肽链和间肽桥（不同长度、不同种…     

高温菌16SrRNA与耐热性关系的初步研究*

通过对80多种超高温菌的基因组G+C含量,16SrRNAG+C含量进行统计分析,结果显示高温菌耐热性与基因组G+C含量之间没有直接关系,而与16SrRNAG+C含量之间明显存在正相关。16SrRNA18helix的二级结构分析显示高温菌生长温度越高,其16SrRNA热稳定性越高。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.