布氏田鼠洞群内社群结构变动与序位的研究

本文通过野外标志流放和实验室观察,研究了洞群内布氏田鼠社群结构的变动及其序位作用。该鼠社群结构变动有明显的季节性。繁殖期为变动期, 贮草期为稳定期。变动期在繁殖前期和繁殖盛期形成2个变动高峰。前者主要是成体(包括老体) 雄鼠的迁移, 后者迁移主体是亚成体鼠。贮草期间洞群成员相对稳定, 迁移减少。社群序位表现为2～3 个等级,即优势鼠、次优势鼠和从属鼠。优势鼠以老体雌鼠为多。繁殖期, 50%以上的从属鼠在陌生鼠群中提高了序位, 30%优势鼠可在陌生鼠中保持高序位。非繁殖期, 进入陌生群后鼠间争斗激烈, 获得优势的比例明显降低。     

不同社群序位布氏田鼠的繁殖行为

在实验室条件下观察了捕自内蒙古草原的不同序位布氏田鼠的繁殖行为特征。结果表明, 雌鼠对雄性配偶存在着激烈的竞争, 高序位雌鼠获得被选择、交尾及产仔的机会最多, 较低序位雌鼠若被选择并且产仔, 则其序位将随之上升; 高序位雄鼠对各个序位雌鼠均可选择, 且在繁殖期间对同性个体表现很强的攻击性, 以获得更多的交配机会。在社群繁殖中高序位雌、雄个体的作用明显高于低序位个体, 这是布氏田鼠种群长期选择进化的生存策略。实验支持了布氏田鼠为混交制、一雄多雌的婚配制度推论。     

繁殖季节和非繁殖季节布氏田鼠种群参数和生理特点的差异

在繁殖季节(6月份)和非繁殖季节(10月份),采集了内蒙古自治区阿尔善宝力格地区的布氏田鼠样本,比较其种群参数与生理指标,探讨了布氏田鼠社群结构和生理特征的季节性差异,并分析了原因。结果表明,布氏田鼠的年龄组成和性比存在明显的季节差异:繁殖季节洞口系数小,种群性比接近1,主要由当年新生鼠和越冬鼠组成;非繁殖季节洞口系数大,种群性比偏雄,主要由当年新生鼠组成。繁殖器官在繁殖季节显著大于非繁殖季节,保持了更高活性。非繁殖季节个体的胴重比更高,且雄鼠高于雌鼠,表明非繁殖季节个体和雄鼠具有更好的营养状态;同时,非繁殖季节个体具有更小的肾上腺和更大的脾脏,说明非繁殖季节中的布氏田鼠表现出更低的应激状态和更强的免疫能力。这些研究结果表明,布氏田鼠的种群参数和生理特点具有明显的季节性特点,这与不同季节中布氏田鼠采取的生存策略有着紧密联系。     

繁殖季节和非繁殖季节布氏田鼠种群参数

在繁殖季节（6月份）和非繁殖季节（10月份）,采集了内蒙古自治区阿尔善宝力格地区的布氏田鼠样本,比较其种群参数与生理指标,探讨了布氏田鼠社群结构和生理特征的季节性差异,并分析了原因。结果表明,布氏田鼠的年龄组成和性比存在明显的季节差异：繁殖季节洞口系数小,种群性比接近1,主要由当年新生鼠和越冬鼠组成;非繁殖季节洞口系数大,种群性比偏雄,主要由当年新生鼠组成。繁殖器官在繁殖季节显著大于非繁殖季节,保持了更高活性。非繁殖季节个体的胴重比更高,且雄鼠高于雌鼠,表明非繁殖季节个体和雄鼠具有更好的营养状态;同时,非繁殖季节个体具有更小的肾上腺和更大的脾脏,说明非繁殖季节中的布氏田鼠表现出更低的应激状态和更强的免疫能力。这些研究结果表明,布氏田鼠的种群参数和生理特点具有明显的季节性特点,这与不同季节中布氏田鼠采取的生存策略有着紧密联系。     

粪便激素水平反映不同出生时期雄性布氏田鼠的繁殖策略

布氏田鼠是我国内蒙古草原的主要害鼠之一,具有明显的季节繁殖特征,不同季节出生个体可能具有不同的繁殖策略,但尚缺乏内分泌证据支持。本研究采用标志重捕法,连续监测大型自然围栏中不同年龄雄性布氏田鼠的繁殖状态和应激水平的季节变化,分析各年龄组雄鼠的繁殖发育策略。结果表明,越冬雄鼠可保持较高的睾丸下降率和睾酮水平至8月初;而部分5月生雄鼠的繁殖期睾酮水平较接近越冬鼠,但8月初已降至年内最低水平,而6月及以后出生雄鼠睾酮始终处于较低水平;这说明越冬鼠的繁殖状态可贯穿繁殖期始终,只有部分5月生雄鼠可能参与当年繁殖,而6月及以后出生雄鼠则不能在当年繁殖。越冬鼠皮质醇水平高于当年鼠,繁殖期高于非繁殖期,这可能是越冬鼠由于繁殖需要而保持较高应激状态,从而造成繁殖盛期后死亡率升高。这些结果说明,不同时期出生的雄性布氏田鼠具有不同的出生后性腺发育模式和繁殖策略,反映出生存与繁殖之间的权衡。     

雌性布氏田鼠对雄鼠气味的辨别

通过雌性布氏田导其配偶和陌生雄鼠气味的辨别实验,以及无交配经历的成年雌鼠对社会等级不同的陌生雄鼠气的辨别实验发现,有生育经历的雌鼠对陌生雄鼠气味的探究行为明显多于对配偶气味的控究,但雌鼠在配偶雄鼠气味周围的停留时间、自身修饰行为和何处行为的发生频次和持续地陌生雄鼠,没有交配经历的雌鼠对处于从鼠地位的雄性个体气味探究行为多于对优势雄性的控究,而其他行为表现没有明显差异。表明,雌性布氏田鼠可以利用气味     

布氏田鼠标志种群的繁殖参数

采用标志重捕和染色观测法跟踪了内蒙古典型草原区布氏田鼠野外种群,按绝对时间年龄研究其种群繁殖参数。结果3表明：4－5月份出生的雄鼠能在当年达到性成熟,性成熟发育历期约为1．5个月,6月后出生的雄鼠当年达不到性成熟。在达到性成熟的当年雄鼠中,多数个体再度转入性休止期,其平均繁殖结束时间要林越冬雄鼠早1个月,而越冬雄鼠则在整个繁殖期保持性活动状态。雌鼠性成熟发育历期约为1个月,首次产仔时间约为2月龄。雌鼠在一年中的产仔窝数与其年龄有关;越冬鼠能产3－4窝,4月份出生的雌鼠能产2－3窝,5月份出生的雌鼠当年能产1－2窝,6月份出生的雌鼠能产0－1窝,7月份之后出生雌鼠当年不参加繁殖,在自然条件下,布氏田鼠一年中最多能产4窝。     

雄性等级对布氏田鼠雌性选择的影响

利用监控录像以及特定行为记录的方法,研究了雄性等级对布氏田鼠气味选择和个体选择的影响。结果表明不论是气味选择还是个体选择,雌鼠动情状态不影响对雄鼠的选择频次,但是动情雌鼠在自我修饰行为频次上高于非动情雌鼠。此外,在气味和个体选择的优先权方面,动情雌鼠更多的优先选择优势雄鼠的气味和个体并与之交配,而非动情雌鼠更多的先选择从属雄鼠的气味和个体。总之,不论是气味选择还是个体选择,布氏田鼠不仅受到被选择雄鼠的地位影响,还与雌鼠的生理状态有关。     

布氏田鼠社会行为对光周期的适应格局

对实验室内不同光周期条件下的布氏田鼠陌生成体—亚成体间社会行为模式的初步研究显示:不同光周期下成体对亚成体（特别是对雄性亚成体）的行为反应具性二型特征,长光照周期下（light:dark,14L:10D)成体与亚成体同性组合间的争斗较异性组合间的明显,容忍性低,其中成体雄对亚成体雄尤甚。短光照周期下（light:dark,10L:14D）成体雄对亚成体雄、成体雌对亚成体雌及亚成体雄的相容性均较成体雄对亚成体雌的容忍性低,尤成体雌对亚成体雄的排斥表现更为突出,其容忍性也较长光照条件下对应组的低。结果表明,不同光周期条件下布氏田鼠成体与亚成体间的社会行为模式不同。在自然条件下,这些行为模式是其对环境季节变化的一种有效适应,它影响种群中未成年个体存活、补充、扩散重组以及社群结构、种群空间格局季节变化,对该鼠的生存和繁殖有利。     

大沙鼠种群空间分布格局的研究

大沙鼠“家族”式的生活方式导致其种群聚集分布格局,且季节差异不显著。每一“家族”占据单一洞群,这些“家族”间在其最适生境内呈明显的均匀分布格局。雄鼠之间为争夺雌鼠在繁殖初期排斥性增强,末期关系趋于缓和。雌鼠对雄鼠的吸引力在整个繁殖期表现强烈,二者呈聚集分布,越冬时则显示扩散趋势;雄鼠的空间格局受雌鼠分布的影响;雌鼠之间为争夺生存空间以利于其繁殖呈强烈的均匀分布格局。     

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.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various