不同饵料养殖黄喉拟水龟效果的研究

用5种不同的饵料(中华鳖配合饲料、蚯蚓、鲢鱼肉、福寿螺肉和河蚌肉)分别投喂黄喉拟水龟幼龟,结果表明,①投喂中华鳖配合饲料的黄喉拟水龟,其增重速度最快,平均日增重和蛋白质效率都最高,且耗料增重比最低,其后依次是: 蚯蚓＞鲢鱼肉＞福寿螺肉＞河蚌肉.②投喂福寿螺肉的黄喉拟水龟,其饵料成本最低,其后依次是: 中华鳖配合饲料＞蚯蚓＞河蚌肉＞鲢鱼肉.③中华鳖配合饲料是养殖黄喉拟水龟较好的饵料,但福寿螺、蚯蚓来源方便,也不失为养殖黄喉拟水龟的好饵料.     

高温胁迫对筛豆龟蝽成虫抗氧化能力的影响

为探索筛豆龟蝽Megacopta cribraria (Fabricius)对高温的耐受性及其体内抗氧化系统对极端高温胁迫的响应机制.以25℃为对照温度,经高温37℃、40℃、43℃和46℃胁迫处理4h后,测定筛豆龟蝽成虫存活率及其体内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)的活性以及总抗氧化(T-AOC)能力和丙二醛(MDA)含量的变化.在37℃～46℃高温胁迫下,筛豆龟蝽成虫存活率与对照无显著差异,其体内SOD和CAT活性较对照组均显著增加,其中,SOD活性在37℃最高,随着温度进一步升高,其活性有所下降,但仍显著高于对照.CAT一直保持较高活性,随着处理温度的升高CAT活性呈逐渐升高趋势,在极端高温46℃时其活性最高.POD活性在37℃～ 40℃显著高于对照,43℃和46℃处理与对照无显著差异.T-AOC活性在各处理温度下均显著高于对照,且随着处理温度的升高T-AOC活性呈先升高后降低趋势.各处理MDA含量与对照无显著差异.筛豆龟蝽体内3种抗氧化酶的活力、总抗氧化能力和MDA在适应高温胁迫过程中发挥了重要作用.     

黄喉拟水龟细胞核DNA含量的分析

以黄喉拟水龟 (Mauremysmutica)的红血细胞为材料 ,以鸡红血细胞为DNA标准 ( 2 5pg/2c) ,采用流式细胞仪测定了黄喉拟水龟及其两个种群的细胞核基因组DNA含量。黄喉拟水龟的细胞基因组DNA含量为 5 16± 0 2 9pg/2c (n =6 0 ) ;南方种群的细胞核DNA含量为 5 19± 0 30pg/2c (n =30 ) ,北方种群为 5 14±0 30pg/2c (n =30 ) ,两个种群的核DNA含量无显著差异 (t=0 6 84 7,df =5 8,P >0 0 5 )。     

温度胁迫对腐食酪螨抗氧化能力的影响

【目的】以储藏物主要害螨腐食酪螨Tyrophagusputrescentiae(Schrank)为研究对象,采用温度胁迫处理,探讨其体内抗氧化系统对不同温度胁迫的响应机制。【方法】采用低温(0、5、10、15、20℃)、常温(25℃)、高温(30、33、36、39、42和45℃)胁迫处理1、2、3h后,测定腐食酪螨超氧化物歧化酶(SOD)、过氧化物酶(POD)和谷胱甘肽-S-转移酶(GSTs)3种酶的活力以及总抗氧化(T-AOC)能力和丙二醛(MDA)含量的变化。【结果】腐食酪螨3种抗氧化酶的活力、总抗氧化能力和MDA含量变化都与胁迫温度和时间密切相关;无论低温还是高温胁迫,SOD酶和GSTs酶活性较对照组均显著增加,说明它们在清除活性氧(ROS)过程中发挥着重要作用。【结论】温度胁迫对腐食酪螨有重要作用,可提高其抗氧化酶活力。     

不同蛋白质水平的饵料对黄喉拟水龟生长影响的研究

依据单因子梯度设计原理,采用进口鱼粉、豆粕为主要蛋白源制成蛋白质含量分别为50.2%、47.3%、44.3%和41.4%共4种试验饵料,研究不同蛋白质水平饵料对黄喉拟水龟生长的影响.结果 表明,经过120 d对80只黄喉拟水龟幼龟的饲养,当饵料的蛋白质含量为47.3%时,黄喉拟水龟的生长速度最快,均显著高于其他3个组(P<0.05);蛋白质效率最高,极显著高于50.2%组(P<0.01),也分别显著高于44.3%组和41.4%组(P<0.05);耗料增重比最低,分别极显著低于44.3%组和50.2%组(P<0.01),也显著低于41.4%组(P<0.05).但不同蛋白质水平的饵料对黄喉拟水龟龟体蛋白质含量没有明显的影响(P>0.05).     

黄喉拟水龟转铁蛋白基因的克隆以及表达特征分析

转铁蛋白在铁的新陈代谢中起着重要的作用,参与细菌感染后的免疫反应。研究克隆了黄喉拟水龟Tf基因组DNA全长序列,并对Tf基因的序列特征进行了分析。序列分析表明,黄喉拟水龟Tf是由两个相似结构域构成的单一肽链,每个结构域包含两个亚基,它们相互作用形成一个深的、亲水的铁结合位点。其基因组DNA由17个外显子和16个内含子组成,与其他脊椎动物Tf基因结构相似,显示了黄喉拟水龟Tf基因在结构上的保守性。同源性分析表明,黄喉拟水龟的Tf基因与鸟类、爬行类的Tf基因同源性最高,约为75%—97%;与哺乳类Tf基因的同源性约为65%—75%;与爪蟾等两栖类的Tf基因也有一定的同源性。荧光定量PCR结果显示,黄喉拟水龟人工感染粘质沙雷氏菌后,Tf基因在其肝脏、脾脏、肾脏及心脏各组织中的表达量均有上调的趋势,这与其他动物经病原刺激后的表达特征具有相似性。       

两种生态型芦苇胚性悬浮培养物对渗透胁迫的生理响应Ⅱ.抗氧化酶类活性的变化

渗透胁迫处理下,沙丘芦苇和沼泽芦苇培养细胞的H2O2含量变化不大,MDA含量随时间延长而降低.抗氧化酶中,沙丘芦苇的SOD、CAT、POD和APx的活力均显著高于沼泽芦苇,显示出比沼泽芦苇更强的ROS清除能力.胁迫初期(O.5 h～1 d)沙丘芦苇细胞中主要表现出SOD、CAT活力的提高,胁迫2 d后4种酶活力均明显被诱导.两种生态型芦苇的PEG适应性培养物APx及SOD酶活力显著提高,POD活性仅沼泽芦苇中升高.提示SOD、CAT主要参与沙丘芦苇在渗透胁迫下的短期响应,而APx与长期响应有关.     

刺激隐核虫感染对褐菖鲉的胁迫及鱼体的免疫应答

为探明刺激隐核虫感染对褐菖鲉生理机能的影响,研究分别用2500、5000、7500和10000幼虫/鱼的刺激隐核虫感染褐菖鲉,并分别检测感染后24h、48h、72h和96h各时间点血清中皮质醇(COR)、血糖(GLU)、总蛋白(TP)含量;肝脏中丙二醛(MDA)和维生素C(VC)含量,超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活力;鳃和皮肤中溶菌酶(LZM)活力。结果显示,随着感染浓度的增加,血液中COR和GLU含量均出现不同程度的升高,其中2500、5000和7500幼虫/鱼组COR含量的最高值均出现在感染后第3天;而TP含量总体呈现逐步下降的趋势,尤其当感染浓度达到5000幼虫/鱼后,TP含量的下降程度明显增加;肝脏中MDA含量呈先降后升的变化趋势,其中24h、48h和72h各点MDA含量的最大值均出现在10000幼虫/鱼组,最小值则集中出现于在2500和5000幼虫/鱼组;而VC含量则与MDA含量的趋势相反;SOD和CAT活力均出现不同程度的升高;鳃和皮肤LZM活力总体呈先上升后回落的变化趋势。综上可知,刺激隐核虫感染会对鱼体造成氧化胁迫和脂质过氧化反应,其严重程度与感染的虫细胞浓度相关。低浓度感染组的鱼所受胁迫较轻,在滋养体脱落后仍具有一定的自我修复能力;而高浓度感染组鱼免疫因子的释放受到抑制或出现紊乱,即便在虫体脱落后,其体质也很难恢复。     

杂交黄颡鱼与普通黄颡鱼幼鱼生长性能及耐低氧能力的比较

实验以杂交黄颡鱼(Pelteobagrus fulvidraco)和普通黄颡鱼幼鱼为实验对象, 拟通过8周的投喂生长和低氧胁迫实验, 比较研究杂交黄颡鱼与普通黄颡鱼的生长性能及耐低氧抗逆性。投喂生长实验: 经过8周的养殖, 杂交黄颡鱼平均体重为(19.60±0.88) g/尾, 显著高于普通黄颡鱼平均体重为(15.74±0.42) g/尾(P<0.05), 杂交黄颡鱼幼鱼较普通黄颡鱼幼鱼体重生长快24.52%; 杂交黄颡鱼幼鱼存活率为(87.78±1.92)%, 显著高于普通黄颡鱼幼鱼存活率(67.78±1.92)% (P<0.05), 杂交黄颡鱼幼鱼比普通黄颡鱼幼鱼存活率高 29.51%; 杂交黄颡鱼的饲料系数为1.18±0.14, 普通黄颡鱼饲料系数为1.36±0.21。低氧胁迫实验: 同时将杂交黄颡鱼和普通黄颡鱼置于在溶氧量(1.48 ± 0.27) mg/L的水体中, 分别在低氧胁迫0、6h、12h和24h后, 检测血清和肝脏中抗氧化酶活性以及脑和肝脏中缺氧诱导基因(HIF-1α)的相对表达量发现: 杂交黄颡鱼和普通黄颡鱼血清和肝脏中乳酸脱氢酶(LDH)活性、超氧化物歧化酶(SOD)活性和过氧化氢酶(CAT)活性在低氧胁迫后 6h以及总抗氧化能力(T-AOC)在低氧胁迫后 12h较低氧胁迫 0均出现显著性变化(P<0.05)且在低氧胁迫6h、12h和24h杂交黄颡鱼抗氧化酶活性均高于普通黄颡鱼; 杂交黄颡鱼和普通黄颡鱼脑和肝脏中缺氧诱导基因(HIF-1α)的相对表达量均在低氧胁迫后出现显著性上升(P<0.05)且在低氧胁迫6h、12h和 24h杂交黄颡鱼缺氧诱导基因(HIF-1α)的相对表达量均高于普通黄颡鱼。从无氧代谢能力、抗氧化能力以及缺氧诱导基因相对表达量3方面分析表明杂交黄颡鱼和黄颡鱼低氧胁迫短时间均具有一定的低氧耐受能力但随着胁迫时间延长均会出现氧化损伤且杂交黄颡鱼的耐低氧能力要显著性高于普通黄颡鱼。     

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.     

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     

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.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

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.     

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).