摄食对原尾蜥虎代谢率的影响

通过测定摄食后原尾蜥虎成体的耗氧量变化,研究摄食特殊热动力作用（SDA）.蜥虎分为摄食黄粉虫幼虫实验组和禁食对照组,两组动物平均体重无显著差异.测定耗氧量前,将所有动物在30℃恒温室内禁食3天.用容积为300 ml的封闭式呼吸室测定两组蜥虎在30℃条件下连续3天的耗氧量,测定间隔时间为4～12 h.禁食组动物实验期间的耗氧量无显著的时间变异,实验组动物耗氧量的时间变异显著,这些结果表明摄食影响原尾蜥虎的代谢率.实验组动物摄食4 h后耗氧量已显著大于禁食组,摄食40 h后两组动物的耗氧量无显著差异.原尾蜥虎达到SDA峰值的平均时间约为20.0 h,SDA峰值耗氧量是禁食对照组动物耗氧量的1.5倍.原尾蜥虎单次摄食实验中的SDA具有进食后耗氧量迅速增加、达到峰值后下降至摄食前水平的典型模式.     

北草蜥幼体短期禁食后的补偿生长

2005年4~5月,对幼体北草蜥(Takydromus septentrionalis)进行了不同短期禁食的饥饿处理后再供食的恢复生长实验。研究用蜥蜴于2005年4月捕自安徽滁州琅琊山,蜥蜴带回实验室禁食至无尿、粪排出后,随机选取状态较好的39条蜥蜴分为禁食0 d(C组)、3 d(S3组)、6 d(S6组)、9 d(S9组)4个组。禁食结束的各实验组蜥蜴用面包虫饱足饲喂至第24 d。恢复生长期间,各实验组蜥蜴的体重随饲喂时间延长而增加。饥饿组消化率和同化效率与C组无显著差异,S3组的消化率显著高于S9组、同化效率显著高于S6和S9组。S3组和S9组的摄食量显著高于C组。本研究结果表明,经各短期禁食处理的幼体北草蜥在恢复生长过程中产生了明显的补偿效应;该补偿现象主要因摄食水平显著增加所致。     

安徽省发现股鳞蜓蜥

2011年6～9月,在安徽岭南省级自然保护区采集到石龙子科蜓蜥属成体标本6号,卵一窝,窝卵数7,孵化后得幼体标本7号,经鉴定为股鳞蜓蜥(Sphenomorphus incognitus),系安徽省蜥蜴新纪录。标本保存于黄山学院动物标本馆。检视所采标本,发现如下变异:吻鳞凹陷;肛前鳞中间2枚显著大于外侧2枚;尾侧扁,尾中段高/宽的比值为1.49(1.23～1.71);体背褐色,有两列黑色斑点;成体和幼体尾部均褐色。此新纪录为研究股鳞蜓蜥的地理分布、形态变异和生态学提供了基础资料。     

三个种群有尾和断尾丽斑麻蜥的选择体温、表面活动和摄食量

用2006年4-6月捕自长安(陕西)、共和(青海)、哈尔滨(黑龙江)三个地理隔离种群尾部完整的丽斑麻蜥(Eremias argus)成年雄体检测断尾对选择体温、表面活动(表面调温个体数)和摄食量的影响。各种群个体均分为实验和对照组,在距尾基部10 mm处切除实验组蜥蜴尾部,获得断尾个体。实验和对照组个体饲养在相同的实验室条件下收集相关数据,历时四周。表面活动的种群间差异是不同种群个体对其所处区域热环境长期适应的结果。断尾个体减少表面活动见于所有三个种群,表明尾自切能导致丽斑麻蜥活动水平的改变。同一种群断尾和有尾个体表面活动的时间格局无显著差异,不同种群表面活动的时间格局无显著差异,这些结果表明丽斑麻蜥白天活动节律具有种的特异性,不受断尾影响。丽斑麻蜥选择体温随纬度或海拔升高而降低,这种变化趋势可能是热环境制约的结果。所有三个种群断尾个体的选择体温均低于有尾个体,表明断尾可改变丽斑麻蜥的体温调定点。丽斑麻蜥摄食量存在种群间差异,长安种群蜥蜴的摄食量显著大于共和种群蜥蜴。三个种群断尾个体均未增加摄食以满足尾再生的额外能量需求,表明增加摄食不是该种蜥蜴补偿断尾能量代价的对     

摄食不同淀粉含量饲料对军曹鱼血清生化指标的影响

实验旨在研究经过10周投喂不同淀粉含量的饲料的养殖实验后, 禁食1d后再投喂对170 g军曹鱼血清生化指标的影响. 饲料以鱼粉为蛋白源, 鱼油、豆油、大豆卵磷脂为脂肪源, 分别添加0%(对照组)、6%、12%、18%、24%和30%的小麦淀粉(以微晶纤维素调平), 养殖实验期间每天饱食投喂2次. 结果表明, 饥饿再投喂饲料后各处理组军曹鱼血糖含量均在(0-5)h升高, 在5h时达到峰值, 并显著高于其他时间组, 摄食5h后开始下降, 7h时基本恢复到投喂前水平; 血清总蛋白含量在不同处理组以及同一处理组的不同时间点上均没有显著差异; 血清中甘油三酯含量在(0-5)h显著升高, 5h后其含量开始下降, 7h时基本恢复到投喂前水平. 其中0%、6%和12%组, 摄食5h后其甘油三酯含量显著高于摄食前与摄食后7h和24h, 而在18%、24%和30%组中, 其含量无显著差异; 0%淀粉组血清中胆固醇含量在(0-2)h显著升高, 2h时达到峰值, 在(2-7)h呈下降趋势, 之后趋于平稳. 其他处理组都是在(0-5)h升高, 5h后开始下降, 在7h时基本恢复到投喂前水平. 18%-30%组, 摄食后5h血清中胆固醇含量显著高于摄食前与摄食后24h. 军曹鱼血清中低密度脂蛋白-胆固醇在(0-5)h显著升高, 摄食5h后其含量开始下降, 7h时基本恢复到投喂前水平, 但各组不同时间点间均无显著性差异. 而血清中高密度脂蛋白-胆固醇含量除在24%添加组中, 摄食后5h显著高于摄食前(0h)及投喂结束后24h处理组, 其他处理之间无显著差异. 综上所述: 170 g军曹鱼禁食再摄入不同含量的小麦淀粉后其血清中血糖含量先升高后降低, 随着饲料中糖添加量的增加, 其峰值先增加, 后趋于平稳. 军曹鱼血清甘油三酯和胆固醇的含量会升高, 对其血清中低密度脂蛋白-胆固醇及高密度脂蛋白-胆固醇影响不显著.       

原尾蜥虎的选择体温、热耐受性和食物同化的热依赖性

(Tsel)、热耐受性和体温对食物同化的影响。Tsel无显著的日时间变化,两性个体的Tsel、临界低温(CTMin)和临界高温(CTMax)无显著的差异。Tsel、CTMin和CTMax的平均值分别为30.9℃、3.2℃和43.3℃。体温对动物食物通过时间有显著的影响。在25℃-33℃范围内,食物通过时间随体温升高而缩短;体温超过33℃后,食物通过时间随体温升高而延长。温度对原尾蜥虎的摄食量、表观消化系数(ADC)和同化效率(AE)有显著的影响。在25℃-37℃范围内,动物在低体温下(25℃和27℃)的摄食量、ADC和AE小于更高体温下动物的对应数值。种间比较结果显示,原尾蜥虎是生活于南方的蜥蜴中具有较强耐受极端体温的种类。     

摄食水平对瓦氏黄颡鱼餐后代谢特征的影响

以新鲜泥鳅(Misgurus anguillicanndotus)肉块为饵料,采用麻醉灌喂的方法,在(25.0±0.5)℃条件下,研究了瓦氏黄颡鱼(Pelteobagrus vachelli)幼鱼[体重(7.03±0.15)g,n=42]不同摄食水平(饵料分别为体重的0%、1%、2%、4%和8%)对餐后代谢反应的影响.结果显示,在不同摄食水平下,瓦氏黄颗鱼摄食代谢均呈现先上升后下降的整体变化趋势;摄食水平由1%增加到8%,实验鱼的SDA耗能、SDA时间和摄食代谢峰值(PMR)分别从3.09 kJ/kg、8 h和56.08 mg O_2/kg·h增加到47.21 kJ/kg、36 h和97.25 mgO_2/kg·h;其中,8%(饱足摄食水平)和4%摄食水平组的代谢率在峰值水平能够持续20 h左右.瓦氏黄颡鱼最大运动代谢率(MMR)为166.5 mg O_2/kg·h,显著大于饱食组PMR(P＜0.05).本研究还表明,随摄食水平上升,瓦氏黄颡鱼通过PMR的增加和SDA时间的延长来满足SDA耗能增加的需求;从摄食4%组和8%组相似的梯形摄食代谢曲线,可以看出瓦氏黄颡鱼在高摄食水平条件(＞4%)下限制了摄食代谢的上升;PMR相对于静止代谢上升倍率较小,暗示其摄食占据的代谢空间较小,进而保留了大量剩余代谢空间用于运动和其他生理活动,这可能与其活跃的觅食活动习性有关.     

锦鲫的摄食代谢与运动代谢及其相互影响

为了探讨锦鲫(Carassius auratus)幼鱼摄食后特殊动力作用(SDA)的变化特征及运动代谢与摄食代谢之间的相互影响,实验首先灌喂锦鲫4%体重的饲料和等体积的纤维素(湿重),测定灌喂前后的耗氧率;另设灌喂饲料、灌喂纤维素、空腹组(对照组)3个组,测定3组的临界游泳速度(Ucrit)和运动耗氧率(MO2);然后在70%、0%临界游泳速度下,分别测定饱足摄食组和空腹组的耗氧率。结果显示:1灌喂饲料后代谢率快速上升,达到峰值后又迅速下降,代谢时间较短,没有一个相对稳定的平台期,灌喂纤维素后代谢率没有显著性变化(P0.05)。提示锦鲫幼鱼的特殊动力作用功率曲线为一个典型的"三角型"模型,且在特殊动力作用总耗能中,生化特殊动力作用占特殊动力作用总耗能的绝大部分,而机械特殊动力作用只占特殊动力作用的极少部分。2锦鲫幼鱼在摄食后临界游泳速度显著下降(P0.05),代谢率显著升高(P0.05)。摄食后的运动过程中,代谢率从摄食开始到代谢率回落至空腹组代谢的标准误范围内的首个数据所对应的时间长度均为6.5 h,且摄食代谢无显著性差异。提示,对锦鲫幼鱼来说,摄食代谢降低了其运动能力,而运动代谢并没有影响摄食代谢。     

有氧运动训练和摄食对中华倒刺鲃幼鱼力竭运动后代谢特征的影响

为了探讨有氧运动训练和摄食对中华倒刺鲃（Spinibarbus sinensis）幼鱼力竭运动后代谢特征的影响,在（25±0.5）℃条件下,将120尾实验鱼[体重（21.35±0.05）g,体长（10.21±0.03）cm]随机分成4组,即:对照组、1、2和4 BL/s（体长/秒,body length/s）训练组,分别放置于不同流速下处理8周。随后测定各实验组心脏和鳃指数以及禁食或摄食（轻度麻醉灌喂体重1.5%的饵料）状态下的力竭运动后过量耗氧。结果发现:4 BL/s训练组的心脏和鳃指数都显著高于其他实验组（P < 0.05）;无论摄食与否,3个训练组运动前代谢率都显著高于对照组（P=0.001）,而各实验组过量耗氧均没有显著差异;在禁食状态下,仅4 BL/s训练组的运动代谢峰值和代谢率增量显著高于对照组,而在摄食状态下,3个训练组的运动代谢峰值和代谢率增量均显著高于对照组（P < 0.005）。与禁食组相比,摄食导致各处理组的运动前代谢率显著上升（P < 0.001）,但对运动代谢峰值没有显著影响;另外,摄食对照组代谢率增量和力竭运动后过量耗氧显著低于禁食对照组（P < 0.05）。研究表明:（1）有氧运动训练显著提高了中华倒刺鲃幼鱼的有氧代谢能力,这可能与其呼吸和循环系统功能的改善有关;（2）力竭运动能够诱导出中华倒刺鲃幼鱼的最大有氧代谢率;（3）摄食削弱了中华倒刺鲃幼鱼无氧代谢能力。     

雄性山地麻蜥选择体温、热耐受性及温度对食物同化和运动表现的影响

研究了捕自安徽宿州的成年雄性山地麻蜥 (Eremiasbrenchleyi)选择体温、热耐受性、温度对食物同化和运动表现的影响。结果显示 :①选择体温、临界高温和临界低温的平均值分别为 33 7、 43 6和 3 3℃。②环境温度在 2 6～ 38℃时 ,对山地麻蜥食物通过时间、摄食量、表观消化系数 (ADC)、同化效率 (AE)和运动表现有显著的影响 ;在 2 6～ 30℃时食物通过时间随温度升高而缩短 ,超过 30℃则随温度升高而延长 ;在 2 6和 2 8℃时 ,摄食量、ADC和AE均小于更高温度的对应值。③体温在 19～ 34℃ ,蜥蜴的疾跑速随体温上升而加快 ,31和 34℃时最快 ,超过 34℃后随体温升高而减慢 ;31和 34℃时的持续运动距离最长 ,超过 36℃后随体温升高而显著缩短 ,但体温 19～ 36℃蜥蜴的持续运动距离无显著差异 ;19～ 34℃蜥蜴的跑道停顿次数较少 ,无显著差异 ,超过 34℃后显著增加。     

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.