海月水母生长规律及水管系统发育研究

本文对烟台海域海月水母水母体阶段伞径、腕长及体重的生长规律进行了研究,并首次对其生长过程中水管系统的发育进行了观察。结果表明,在人工培养条件下,海月水母体重(W)与伞径(D:15~150㎜)呈幂函数增长;腕长(L)与伞径(D)呈线性关系;伞径生长曲线方程为：Dt = 4×10-6t4-0.0014t3 0.1087t2 0.5079t 9.428 (R2=0.9993)。。海月水母初生碟状体出现主辐管与间辐管,3日龄时碟状体出现从辐管,11日龄时出现环管、分离点。随着水母的生长,伞径增大,水管系统的分离点数与聚合点数逐渐增多,成熟时1/4伞部分离点数最多为66个,聚合点数最多为32个。     

黄颡鱼和杂交黄颡鱼“黄优1号”形态及性腺发育的比较

选取相同养殖条件的10月、22月和34月龄的黄颡鱼和新品种杂交黄颡鱼(黄颡鱼P. fulvidraco♀×瓦氏黄颡鱼P. vachelli♂)“黄优1号”进行形态及性腺发育的比较研究。通过形体指标测量发现“黄优1号”生长性能显著优于黄颡鱼; 在22月和34月龄黄颡鱼中, 雄性的体重是雌性的2倍左右, 雄性生长速度显著高于雌性; 而在“黄优1号”中, 两性生长异形现象被显著减弱。基于性腺解剖形态分析发现雌性“黄优1号”卵巢完全退化, 呈细线状结构且没有卵子产生, 故“黄优1号”雌鱼完全不育; 雄性“黄优1号”精巢组织呈现透明状和退化状态。精巢组织切片HE染色分析发现10月龄“黄优1号”的精小囊为空腔状几乎没有精子产生, 22月和34月龄“黄优1号”的精小囊内出现极少量精子。计算机辅助精子分析系统(CASA)分析发现, 相比于黄颡鱼, “黄优1号”精巢中精子量非常少, 有效活力低下; 经过繁殖能力测试, 22月龄“黄优1号”雄鱼不具备繁殖能力。新品种杂交黄颡鱼“黄优1号”在生长性能提高上显现了杂交优势, 具有推动黄颡鱼产业发展的潜力。     

长吻鮠精巢发育的分期及精子的发生和形成

长吻鮠精巢的发育分为精原细胞增殖期、精母细胞生长期、精母细胞成熟期、精子细胞出现期,精子完全成熟期和精子退化吸收期。精巢的后1/3不产生也不贮存精子,精子的发生和形成经过精原细胞、精母细胞、精子细胞到精子的一系列过程。精原细胞有两种类型。精子无顶体,有中心粒帽,中片长,核凹窝和线粒体发达,鞭毛具侧鳍。     

长吻wei精巢发育的分期及精子的发生和形成

长吻wei精巢的发育分为精原细胞增殖期、精母细胞生长期、精母细胞成熟期、精子细胞出现期、精子完全成熟期和精子退化吸收期。精巢的后1/3不产生也不贮存精子,精子的发生和形成经过精原细胞、精母细胞、精子细胞到精子的一系列过程。精原细胞有两种类型。精子无顶体,有中心粒帽,中片长,核凹窝和线粒体发达,鞭毛具侧鳍。     

大弹涂鱼性腺发育的组织学观察

于光镜下对大弹涂鱼性腺切片作了组织学观察,对大弹涂鱼卵细胞和精子发育规律进行研究。结果表明:大弹涂鱼在一个生殖季节中只能产卵1次,大弹涂鱼属于一次性产卵类型。大弹涂鱼3月卵母细胞进入大生长期发育阶段,4—6月为繁殖盛期,7—8月为繁殖末期。10月卵巢基本修整完毕,进入Ⅱ′恢复期。卵细胞发育可分为6个时相:卵原细胞、卵母细胞单层滤泡、卵母细胞出现脂滴和卵黄、卵母细胞卵黄充满、卵母细胞核极化、卵母细胞退化时相。卵母细胞膜单层,由具有辐射纹的放射带构成,滤泡膜细胞分泌而成的次级卵膜成为成熟卵子的附着丝。大弹涂鱼2月精巢开始发育,5月GSI值达最高值,平均成熟系数达0.70%,排精量最旺盛,出现高峰。7—9月GSI值明显下降。11月至翌年2月GSI值波动于0.08%—0.20%之间,变辐小,此期间精巢处于静止发育状态。大弹涂鱼的精巢属于小叶型结构。精子发育分为6个时期:精原细胞期、精原细胞增殖期、精母细胞生长成熟期、精子细胞变态期、精子成熟期和退化吸收期。繁殖季节精小叶内充满精子,精小囊消失。       

中华鳖性腺的发生与发育研究

为了揭示中华鳖性腺的发生与发育规律,在(32±0.5)℃温度下孵化鳖卵,72h时,从组织切片中可见原始生殖细胞移向中肠附近的内胚层;第5天生殖嵴形成;第13天性腺分化为皮质和髓质;第16天性腺开始分化为精巢或卵巢,至第22天时分化结束,形成精巢或卵巢.胚胎期、稚鳖和1龄鳖的性腺均呈短细管状,表面光滑,无色,胶状透明;2龄、3龄、4龄鳖的精巢呈长椭圆形.稚鳖的卵巢发育至卵原细胞期,组成精巢的曲细精管不明显,管内为精原细胞;1龄幼鳖的卵巢发育至初级卵泡期,精巢的曲细精管内精原细胞的数量增加;2龄和3龄鳖的卵巢处于生长卵泡期,3龄末的卵巢内可见到成熟卵泡,2龄鳖的曲细精管内出现初级精母细胞,3龄末的曲细精管开始出现精细胞和精子;4龄鳖的卵巢发育至成熟卵泡期,曲细精管内由管壁向管腔依次为精原细胞、初级精母细胞、次级精母细胞、精细胞和精子.结果表明,在(32±0.5)℃温度下,鳖胚发育至22d时,精巢或卵巢形成;在自然条件下,中华鳖至4龄时,性腺才完全发育成熟.     

黄颡鱼性腺分化的组织学观察

运用组织学方法,观察黄颡鱼(Pelteobagrus fulvidraco)性腺分化过程.结果表明,在水温(20±1)℃条件下,卵巢分化时间明显早于精巢.卵巢分化最早发生于孵出后13 d左右,其主要标志为原始性腺横切面上出现一个组织突起,进而形成卵巢腔;精巢分化的最早标志为精小叶和输精管的形成,开始于孵出后55 d.在发育早期,雌性生殖细胞的活动及分化明显早于雄性生殖细胞.孵出后25 d,卵原细胞开始通过有丝分裂快速增殖,孵出后34 d左右进入成熟分裂阶段;精原细胞在孵出后55 d时才开始大量增殖,成熟分裂最早发生于孵出后64 d.     

雄烯二酮对赤点石斑鱼内分泌及性腺发育的影响

采用腹部埋植法,应用连续组织切片技术、放射免疫测定方法和半定量RT-PCR技术,检测了间隔30d3次埋植不同剂量（高剂量H：100μg／g体重,低剂量L：10μg／g体重）的雄烯二酮（4-androstene-3,17-dine,ADSD）诱导2龄赤点石斑鱼性腺发育过程中血清性类固醇激素含量、芳香化酶表达和活性的变化。结果显示：第1次埋植ADSD后30d即可诱导雌性赤点石斑鱼发生不同程度的性逆转,性腺成熟指数明显下降,性腺中卵细胞退化,精原细胞增殖,出现大量精母细胞和精子细胞,第1次埋植ADSD后30d经轻微挤压腹部有10％（低剂量组）和15％（高剂量组）的鱼可排精;第2次埋植后30d明显提高性逆转效果,排精率分别达到80％和86．7％,性逆转雄鱼的精巢在组织结构上与正常雄鱼精巢一样,精子活力与正常雄鱼相同,对照组鱼卵巢发育良好;第3次埋植后30d排精率分别为90％和80％,埋植ADSD后性腺芳香化酶（P450aromA）表达和活性显著降低,脑芳香化酶（P450aromB）表达显著升高,前脑芳香化酶活性显著升高,血清T,11-KT水平显著高于对照组,而血清E2水平先升高,然后逐渐降低。说明血清T,11-KT水平增加,性腺芳香化酶表达及活性降低在控制雌雄同体的赤点石斑鱼的性转化和精子发生中起重要作用。     

卵胎生硬骨鱼褐菖(鱼良)鲉精巢的周期发育

研究了卵胎生硬骨鱼褐菖(鱼良)鲉(Sebastiscus marmoratus)的精巢结构和生殖周期.褐菖(鱼良)鲉精巢属于小叶型.每年8～9月,精巢处于精原细胞增殖期.初级精原细胞分裂增殖,产生次级精原细胞.后者和支持细胞组成精小囊.10月～翌年1月进入精子发生期.精小囊中的生殖细胞进一步发育,逐渐形成精子.2～7月是精子退化吸收期,精巢中仅有初级精原细胞和残余的精子.在生殖季节,精子经由输出管和输精管运至尿殖突,通过体内受精方式送入雌鱼生殖道.     

萍乡肉红鲫的性腺发育研究

萍乡肉红鲫(Pingxiang red-transparent crucian carp,Carassius auratus L.)是在江西省萍乡地区分布的天然三倍体鲫突变体经人工选育后获得的遗传性状基本稳定的后代,具有两性生殖和雌核生殖两种生殖方式.研究以F5代萍乡肉红鲫为材料,自孵化后每满1个月开始取性腺,观察了其卵巢1周年性成熟和精巢的发育过程,结果表明萍乡肉红鲫的性腺为1年成熟类型.卵巢发育进程町以分为6个时期,卵母细胞发育相应可分为6个时相.统计了卵巢成熟系数周年变化,体重为95 g左右的雌性萍乡肉红鲫,其成熟卵巢的成熟系数约为(11.73±2.8)%,成熟的卵母细胞内充满卵黄,相对怀卵量为(3018±310)粒/g.萍乡肉红鲫精巢属于小叶型,在精小叶中可观察到不同发育阶段的生殖细胞.由精原细胞分裂而来的仞级精母细胞经分裂增殖,产生次级精母细胞并最终发育成为精子.萍乡肉红鲫的精巢发育程序与普通鲫鱼和鲤鱼相似,卵巢和精巢的发育过程基本同步,孵化后50日龄内性腺分化不明显,到70日龄左右开始出现雌雄分化,3月龄发育为第1期,4-5月龄发育为第2期,6-7月龄发育至第3期,7-10月龄可见第4期卵巢,1年即可成熟产卵,精巢可排出精液.结果表明,该鲫鱼突变体的性腺发育与普通二倍体鲤(鲫)鱼的性腺发育方式类似.     

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.