中国水螅属一新种(螅形目,水螅科)

记述采自北京地区水螅属1新种：北京水螅Hydra beijingensis sp．nov．。新种的主要鉴别特征是出现体部与柄的分化;钩刺丝囊内刺丝缠绕具有2种形态：大部分钩刺丝囊(占2／3左右)内顶端基部刺丝呈4～5圈横向弹簧状缠绕,而占所观察刺丝囊总数1／3左右的囊内刺丝为不规则缠绕和纵向缠绕。标本保存在哈尔滨师范大学生命与环境科学学院生物学系无脊椎动物研究室。     

中国水螅属一新种(水螅纲,水螅科)

报道采自广东省肇庆市的淡水水螅1新种,多形水螅Hydra polymorphus sp.nov.,研究标本均来自1只水螅的单系繁殖群体,测量数据经生物统计学处理。新种的钩刺丝囊外形及内部刺丝盘旋均有多种形态,故新种名以此命名。所有研究标本保存于深圳大学生命科学学院。     

中国水螅属一新种(螅形目,水螅科)

记述水螅科水螅属1新种：哈尔滨水螅Hydra harbinensis sp.nov.。本种与其它已报告的雌雄同体水螅有明显区别,只与美洲的海曼水螅较为相似,但也有不同,其与海曼水螅的区别为：生活于静水,能直立并可横向附着生活,实验室培养用储放的自来水可正常生活及生殖。粘刺丝囊小型。胚鞘的鞘膜表面有网格,每根圆锥形的棘刺发自每一网格中央,棘刺无结节,不分叉。精巢数目为2～6个,卵为4～6个。模式标本保存于哈尔滨师范大学生命与环境科学学院生物学系无脊椎动物研究室。     

水螅刺丝囊的分离与观察

水螅的刺丝囊依据其形态和功能,有穿刺丝囊、钩刺丝囊、粘刺丝囊和卷刺丝囊4种,是淡水水螅分类的主要依据之一.使用多种化学试剂探索分离刺丝囊的方法,实验发现利用10%的MgSO4或3%的NaCl处理离体触手5～6 min,用高纯水清洗后制作装片观察,可以获得最佳的显微图片和观察效果.最后初步探讨了不同体区刺丝囊的结构特点.     

异种嫁接的水螅畸形体初步观察

摘要：把强壮水螅（Hydra robusta）和普通水螅（H.vulgaris）除头后进行异种切口嫁接实验,共获得3例畸形体,对其进行280 d的培养,获得78只畸形子代。追踪观察发现：①畸形体及其无性生殖子代均具有2种钩刺丝囊（强壮水媳钩刺丝囊和普通水螅钩刺丝囊）;②其身体伸展时最长达52 mm;③无性出芽生殖的平均...     

水螅的摄食与生殖

水螅是一类只有散漫神经 (神经网 ) ,结构简单 ,在淡水中固着生活 ,体呈圆柱形的动物。在水螅的摄食和生殖等方面笔者观察到一些有趣的现象 (见本期封四彩色照片 ) ,现做简要介绍。1　摄食和消化水螅喜食水蚤、剑水蚤和小型的环节动物。水螅捕食没有数量选择。当游动的 1个或几个水蚤撞到水螅任一触手或几条触手时 ,触手上密布的具有捕食和防御功能的 4种刺丝囊同时放射刺丝 ,将其抓住、麻醉、杀死。同时受刺激的散漫神经引起水螅全身的收缩 ,触手和躯体已缩成一团 ,此时 ,如又一被捕获物撞到收缩的触手上 ,剩余的刺丝囊能够继续放射刺丝 ,…     

水螅的刺细胞及其功能

腔肠动物具有其他动物所没有的特殊的刺细胞(cnidocyst),因而旧称刺胞动物(Cnidaria)。刺细胞来源于未分化的间细胞,发育过程很复杂(图1见封二,下同)。成熟的刺细胞一般呈椭圆形,端部的一侧具一小针状的刺针(cnidocil),细胞核位于细胞的基部。刺细胞中含有一囊状的细胞器称刺丝囊(nematocyst)(图2)。在腔肠动物中已识别出的刺丝囊有20余种。Weill(1923)研究了     

中国水螅属一新种(水螅虫纲:螅形目)

报道采自黑龙江省漠河地区北极村水螅１新种,即漠河水螅Ｈｙｄｒａ ｍｏｈｅｎｓｉｓ ｓｐ．ｎｏｖ．,模式标本保存于哈尔滨师范大学生物学系无脊椎动物教学研究室。     

五种水螅基因组DNA的RAPD多态性研究

利用RAPD技术对水螅科2属5种水螅进行了基因组DNA多态性研究.80个随机引物筛选出18个引物,共扩增出303个清晰稳定的DNA片段,分子量在0.3～3.0kb之间.以UPGMA聚类法构建树状图,阐明水螅属种的分类关系:大庆水螅Hydra daqingensis、北京水螅H.beijingensis和强壮水螅H.robusta 3种分成两组并聚在一起;不同属的漠河水螅H.mohensis和绿水螅Chlorohydra sp.聚为一支;由此2属5种水螅分为两个支系.     

水螅和涡虫的立体生态养殖

水螅（Ｈｙｄｒａ）和三角头涡虫（Ｄｕｇｅｓｉａ）是动物学实验与研究的重要材料,但由于河流污染和生态环境的破坏,野外已不易采到。人们曾摸索了许多单纯饲养水螅和涡虫的方法,但由于投饵和经常换水等问题,工作量较大而不能长期养殖。我们在研究野外水螅和涡虫共同栖息的小生境的基础上,结合前人的一些经验,于１９９４年开始在室内进行了水螅和涡虫的立体生态混养实验,获得了成功。１　饲养缸的制作和安放用０．５ｃｍ厚的普通玻璃制作长５５ｃｍ、宽３３ｃｍ、高２５ｃｍ和长３５ｃｍ、宽３５ｃｍ、高１５ｃｍ的玻璃缸各１个,前…     

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.