北江间的年龄与生长特征

于2007年4月至2009年3月间,在广东北江中上游地区采集间(Hemibarbus medius)样本640尾,以鳞片作为年龄鉴定材料,对其种群的年龄与生长特征进行了研究。结果表明,间鳞片上年轮结构清晰,前区主要表现为疏密型,而侧区主要为切割型;鳞片的边缘生长率表明,间年轮的形成期主要为3~4月份。样本由0+~6+龄7个龄组组成,其中,雌性由1+~6+龄6个龄组组成,主要为1+~4+龄;而雄性由1+~5+龄5个龄组组成,主要为1+~3+龄;在4+~6+龄个体中,雌性78尾,雄性27尾,雌性显著多于雄性。体长(L,cm)与体重(W,g)的关系为W=0.011L3.149(♀)、W=0.011L3.135(♂),协方差分析表明,雌雄个体体长与体重关系的差异不显著,所有样本体长与体重的关系式为W=0.011L3.148。体长与鳞长(R,mm)呈幂函数及直线关系,关系式分别为L=6.387R0.853、L=4.569R+2.587。拟合的von Bertalanffy生长参数为L∞=29.855 0 cm,k=0.223 1,W∞=483.889 8 g,t0=﹣0.928 2龄。对理论体长与实测体长、理论体重与实测体重进行χ~2检验,两者的差异均不显著,表明von Bertalanffy生长方程能较好地拟合间的生长。体重生长的拐点年龄为4.21龄,拐点体长约为20.37 cm,体重约为166.19 g。作为渔业保护对策,建议起捕年龄3龄以上或体长17 cm以上的个体。     

北江侧条光唇鱼的年龄与生长特征

于2007年7月至2009年6月间,在北江中上游地区采集了358尾侧条光唇鱼(Acrossocheilus parallens)样本,以鳞片作为年龄鉴定材料,对其年龄与生长特征进行了研究。侧条光唇鱼鳞片上年轮结构清晰,前区主要为疏密型,而侧区主要为切割型;鳞片的边缘生长率显示,其年轮的主要形成期为2~3月份。样本中的雌性由1+~5+龄5个龄组组成,优势龄组为1+~3+龄;而雄性由1+~4+龄4个龄组组成,优势龄组为1+~2+龄。雌鱼的体长(L,cm)范围为5.7~14.8 cm,集中于7.0~13.0 cm之间;体重(W,g)范围为4.75~108.40 g,集中于10.00~30.00 g之间。雄鱼的体长范围为5.7~12.6 cm,集中于7.0~11.0 cm之间;体重范围为4.40~61.50 g,主要集中于10.00~20.00 g之间。体长与体重的关系为W=0.017L3.167、W♀=0.017L3.198、W♂=0.023L3.025,协方差分析表明,雌、雄个体在体长与体重关系上,差异显著。体长(L,cm)与鳞径(R,mm)呈线性关系,L♀=3.126R+1.869、L♂=2.875R+2.152。拟合出Von Bertalanffy生长参数,雌性L∞=17.143 5 cm,k=0.270 5,W∞=150.347 4 g,t0=﹣0.614 6龄;雄性L∞=17.236 5 cm,k=0.226 9,W∞=126.468 6 g,t0=﹣0.921 5龄。雌鱼体重生长的拐点年龄为3.68龄,拐点体长约为11.8 cm,体重约为45.26 g;雄鱼的拐点年龄为3.96龄,拐点体长约为11.5 cm,体重约为37.60 g。作为渔业对策,建议起捕年龄3龄以上或体长10 cm以上的个体。     

怒江东方墨头鱼的年龄结构与生长特性

2006年10月至2008年10月于怒江采集东方墨头鱼(Garra orientalis)136尾,体长54～167mm,体重3.0～114.6g。研究了其年龄、生长等生物学特性,通过耳石轮纹估算东方墨头鱼的年龄,显示怒江东方墨头鱼由10个年龄组组成。耳石半径与体长关系为:L=0.061R1.131(n=125,R2=0.907),体长与体重关系为:W=0.1×10-4L3.160。von Bertalanffy生长参数由退算体长估算:雄性L∞=224.79mm,k=0.094/年,t0=0.51年;雌性L∞=228.91mm,k=0.091/年,t0=0.639年;总体L∞=227.78mm,k=0.091/年,t0=0.588年。体重生长拐点雄性12.15龄、雌性13.75龄。     

鄱阳湖黄鳝的生长特征

以基舌骨和脊椎骨作为年龄鉴定的材料,研究了鄱阳湖黄鳝(Monopterus albus)种群的生长特征.结果表明,种群的年龄结构分别为:雌性1～5龄,雄性2～6龄,2～5龄为黄鳝性别的过渡期(间性).2～4龄为优势年龄组,占渔获物的89.75%,相对应的体长为30～50 cm,体重为30～120 g.体长(L)与体重(W)的关系为:W=0.000 4L3.2601(♀);W=0.001 4L2.9008(∮).按生长指标值分析,阶段生长可以明显地划分为两个时期,即2龄前的生长迅速期和2龄后的生长稳定期.拟合的Von Bertalanffy生长参数分别为雌性L∞=78.5 Cm,k=0.174 02/y,t0=-1.203 2 Y,W∞:602.01 g;雄性L∞=102.3 cm,k=0.118 45/y,t0=-1.310 1 Y,W-=947.32 g;生长特征参数分别为ψ=3.030 3(♀)和ψ=3.093 4(∮);雌雄个体生长差异显著.     

五大连池鳙的生长分析

为了分析五大连池鳙(Aristichthys nobilis)的生长情况,于2013和2014年在五大连池三池及二池随机采集223尾鳙样本,采用鳞片鉴定其年龄,退算体长、体重。同时采用von Bertalanffy生长方程分析了五大连池鳙体长、体重的生长规律。结果显示,鳙渔获物的平均体长、体重分别为54.61 cm和3 280.53 g,由3+~8+共6个年龄组组成,以5+龄个体为主,占总数的50.67%。五大连池鳙体长(L,cm)、体重(W,g)之间关系式为W=0.0289 L2.901(n=223,R=0.974)。体长、体重von Bertalanffy生长方程分别为:Lt=97.619[1﹣e﹣0.140(ti﹣0.004)]和Wt=17113.260[1﹣e~(﹣0.140(ti﹣0.004))]2.901。鳙体长生长速度曲线无拐点,随着年龄的增加生长速度逐渐降低。体重的生长速度曲线具有拐点,拐点年龄为7.61龄,所对应的体长和体重分别为63.94 cm和5 012.82 g。采用生长特征指数?对比分析五大连池与其他水域鳙的生长,结果显示五大连池鳙的生长较为缓慢,栖息环境的水温、饵料生物密度是影响五大连池鳙生长的重要因素。有效提高鳙生长速度的关键措施在于降低放养密度。     

乌苏里江唇(鱼骨)的鳞片和生长特征

依据238尾鱼的测量数值,研究了乌苏里江野生唇钱(鱼骨)(Hemibarbus labeo)的鳞片及生长特征,并调查了乌苏里江抓吉镇江段唇(鱼骨)的捕捞资源情况.结果表明,唇(鱼骨)的鳞片较大,为规则圆鳞,年轮特征清晰,易于分辨,鳞径(R鳞径)与生长时间(年龄t)的回归方程为R鳞径=0.858 3t 2.275(=238,r=0.986 8),体长与鳞径的回归方程为L=4.332 6R鳞径 0.029 3(n=238,r=0.990 3).乌苏里江唇(鱼骨)体重与体长的回归方程为W=0.011 5L3.0868(N=238,r=0.996 2),其生长特征适合Von Bertalanffy生长方程,体重的生长拐点t=4.59龄,W=340.90 g.在乌苏里江抓吉镇江段主要捕捞唇(鱼骨)的时间从每年开冰期4月20日到封冰期11月15日左右,其捕捞量随季节的变化而不同,4～5月、10～11月数量最多,为100～150 kg/d,6～7月为50～100 kg/d,8～9月较少,为30～40 kg/d.     

叶尔羌高原鳅的年龄、生长与繁殖特征

分析了2008年5月采自新疆克孜河264尾叶尔羌高原鳅(Triplophysa yarkandensis)的年龄结构、生长特征和繁殖力。结果显示,种群年龄由2～11龄组成,其中2～4龄组个体占94.49%。平均体长和体重雌性为(9.39±2.10)cm和(16.55±15.85)g,雄性为(9.17±2.27)cm和(15.38±15.20)g,两者在雌雄群体间差异均不显著(P0.05)。体长和体重关系式为W♀+♂=0.014 0L2.988 9(r=0.975 4),W♀=0.016 7L2.889 5(r=0.980 9),W♂=0.011 7L3.083 1(r=0.975 7)。生长指标和年增重均以4龄组最大,分别为1.86和18.79 g/年。雌雄性比为0.7∶1.0。2龄性即成熟。最小成熟体长和体重雌性为6.2 cm和4.46 g,雄性为4.6 cm和1.67 g。绝对怀卵量为6 136～405 555(平均28 716±42 698)粒,相对怀卵量为672～6 134(平均2 310±1 427)粒/g。卵径呈单峰型分布,推测为不分批产卵类型。依据同年8月采集的19尾幼体日龄推算,其繁殖期为5月下旬至6月下旬。     

光倒刺鲃的年龄与生长的初步研究

研究了光倒刺鲃(Spinibarbus hollandi)的年龄与生长规律,结果表明:光倒刺鲃鳞片年轮特征主要为疏密切割型。体长与鳞长呈直线相关L=44.44R-11.69,体重与体长呈指数函数相关W=0.0258L2.9125,4龄以前生长较快,生长指标高,体长指标高,体长和体重的相对增长率大,其生长规律可用Von Bertalanffy方程表达:Lt=67.3[1-e-0.2018(t-0.1338)],Wt=5441.44[1-e-0.2018(t-0.1338)]3。体重生长曲线的拐点位于t=5.678,拐点体长Lr=45.313cm,拐点体重Wr=1660.885g。光倒刺鲃雌性一般在3~4龄性成熟,雄鱼3龄时性成熟。     

雅鲁藏布江下游弧唇裂腹鱼的年龄结构与生长特性

研究以采自雅鲁藏布江下游墨脱段的928尾弧唇裂腹鱼(Schizothorax curvilabiatus)为研究对象, 对耳石、脊椎骨和鳃盖骨三种年龄材料的准确性进行比较, 并对其种群年龄结构和生长特性进行研究。结果表明, 耳石是鉴定弧唇裂腹鱼最适合的年龄材料。弧唇裂腹鱼体长为48—508 mm, 体重为1.8—1898.9 g。体长体重关系式为W =2.279×10–5 SL 2.931。雌鱼最大年龄43龄, 雄鱼最大年龄23龄。von Bertalanffy生长方程为雌性: L_t= 590.2[1–e–0.096(t–0.282)], W_t=3016.8[1–e–0.096(t–0.282)]2.931; 雄性: L_t=575.3[1–e–0.090(t+0.011)], W_t=2798.9[1–e–0.090(t+0.011)]2.931。弧唇裂腹鱼雌性和雄性的拐点年龄分别为11.5龄和11.9龄。研究结果表明弧唇裂腹鱼生长缓慢、寿命较长, 为典型的K-对策选择者。随着雅鲁藏布江下游河流环境受到的人为干扰逐渐加大, 应从控制捕捞、栖息地保护和加强人工繁育等方面保护弧唇裂腹鱼的种群资源。     

长湖达氏鲌的生长特性及其资源现状

2015年9月至2016年8月在湖北长湖采集达氏鲌(Culter dabryi)样本592尾,对其年龄、生长及资源状况进行了研究。结果表明,长湖达氏鲌种群的年龄组成为1~7龄,其中以1~4龄鱼为主,占样本总量的91.38%;达氏鲌属匀速生长类型,其体重(W)和体长(L)的关系式为W=0.008L3.148(n=592,R~2=0.995,P0.01),且无明显性别差异;采用von Bertalanffy生长方程分别拟合体长、体重与年龄的关系,其表达式分别为,体长Lt=49.103[1﹣e-0.194(t+0.268)],体重Wt=1668.330[1﹣e-0.194(t+0.268)]3.148,生长拐点年龄t=5.64龄,对应体长33.4 cm,体重502.4 g;目前长湖达氏鲌总死亡系数Z=0.80,自然死亡系数M=0.42,捕捞死亡系数F=0.38,资源开发率E=0.48/年,根据体长股分析法估算出长湖达氏鲌2015~2016年资源量为1 809 710尾(15.18 t)。为保持长湖达氏鲌资源稳定,建议捕捞体长33.4 cm以上个体。     

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.