高寒地区高原鼢鼠消化道形态的季节变化

对青海高原地区的高原鼢鼠在自然环境中消化道各器官的长度及重量的季节变化进行了测定,结果显示总消化道保持相对的稳定性,长度、鲜重及于重均相对稳定,而含内容物器官重季节性变化明显。胃的变化相对较稳定,但长度季节性变化显,草枯黄期值最高,草生长盛期最低;小肠的鲜重在草返青期明显低于草生长盛期和草枯黄期;盲肠的变化最大,其长度和含内容物器官重草返青期明显高于其它季节。大肠的干重于枯黄期显增加。各器官的     

根田鼠消化道长度和重量的变化及其适应意义

动物消化道的形态与食性、食物质量以及动物量的需求密切相关。本文对青海高原地区的根田鼠在自然环境中消化道各器官的长度及重量进行了测定,结果显示总消化道及各器官（胃、小肠、大肠和盲肠）的长度,含内容物重（鲜重和干重）在各物侯期间具显著的变化,各项指标均于环境条件较好的植物生长盛期最低,于条件较差（食物纤维素含量高及低温）的植物枯黄期或返青期较高。各器官所反应程度不同,其中小肠的反应最为强烈,表明消化道     

洞庭湖不同生态类型区黑线姬鼠消化道重量和长度的季节变化

对洞庭湖3种不同生态类型区(农区、林区、农林交错区)不同季节黑线姬鼠消化道各器官长度、鲜重和干重的测量表明,在3种生态类型区中,黑线姬鼠消化道各器官鲜重和干重季节变化显著。农区和林区消化道各器官的鲜重和干重在春季和冬季显著重于夏季和秋季,农林交错区消化道各器官鲜重和干重在春季显著重于夏季和秋季,这可能与春季和冬季黑线姬鼠能量需求增加、食物缺乏和食物质量下降有关。在同一季节,3种生态类型区之间消化道各器官长度、鲜重和干重均无显著性差异。这与3种生态类型区间黑线姬鼠食物变化较小有关。关于消化道各器官长度变化方面,除了农区的大肠长度有显著季节性差异外,其它指标均无显著季节性差异。以上结果表明黑线姬鼠消化道各器官在外界环境因素的影响下能产生不同的反应,消化道形态的变化是黑线姬鼠面临外界胁迫因子时的一种消化对策。     

草兔消化道长度和重量的季节变化

为探讨栖息于陕北黄土丘陵沟壑区草兔的消化道特征与季节变化之间的适应关系,对自然环境中不同季节草兔消化道长度和重量进行了测定。结果表明:草兔的消化道几乎各项指标都表现为冬季最高,夏季最低。但冬季和秋季、春季和夏季的多数指标无显著性差异,而夏季和秋季的多数指标则差异显著。孕兔比未孕兔仅在胃干重和盲肠长两个指标方面显著增大。这些结果表明,草兔消化道长度和重量的差异与其消化适应策略有关。在低温、食物质量下降等因子的胁迫下,草兔通过调整消化道形态结构来适应能量需求的增加,这反映了该物种对黄土丘陵沟壑区冬季严寒、全年干旱少雨、降雨主要集中在夏季且日温差较大等环境特征的适应模式。     

洞庭湖区社鼠消化道长度和质量的季节变化

对洞庭湖区社鼠（Niviventer confucianus）自然种群四季的消化道各器官的长度和质量进行了测定。结果表明。消化道指标季节变化明显。总体消化道含内容鲜质量、净鲜质量与干质量均具有显著的季节变化。以冬、春季较高。夏、秋季较低。消化道各器官的变化与总消化道不尽相同。其中,以胃的变化相对比较稳定。仅长度的变化达显著水平,以冬季最短,夏、秋季较长。这是动物为适应繁殖季节能量需求而增加摄食量的反应,也与夏秋季食物丰富度有关。小肠、盲肠、大肠的长度和质量指标（内容鲜质量、净鲜质量和干质量）以冬、春季较高。夏、秋季较低。这是该鼠对冬、春季低温和食物匮乏的适应性反应。总体来说。洞庭湖区社鼠为适应夏、秋季繁殖盛期能量需求增加的主要对策是增加摄食量;而为适应冬、春季低温环境和食物数量和质量减少的主要对策是增大消化道。提高消化效率。     

甘肃鼢鼠适应地下生活的消化道形态和结构的季节可塑性

甘肃鼢鼠(Myospalax cansus)是终生营地下生活的小型哺乳动物,为研究其在自然环境中的消化对策和调节,探讨地下鼠消化道的可塑性,测定了不同季节消化道各器官长度、重量及各器官的组织结构。结果显示,甘肃鼢鼠总消化道长度、各消化器官长度和含内容物总重量无显著季节差异。总消化道及各器官的鲜重和干重多在春季最高,含内容物重量于秋季较高。组织结构有显著性季节变化,黏膜层和肌层的厚度及肠道绒毛高度春季最高。结果表明,甘肃鼢鼠主要依靠肠道重量的增加和组织结构的可塑性变化来适应相对稳定的地下生活环境,无需增加消化器官长度满足其能量需求。     

高原鼢鼠内脏器官与海拔的相关性研究

小型哺乳动物内脏器官的质量和消化道长度具有高度可塑性,是其对环境适应的重要指标。本研究通过对高原鼢鼠内脏器官随海拔梯度变化的比较研究,旨在从形态结构方面来探讨高原鼢鼠对环境和低氧的适应机制。结果显示,雄性高原鼢鼠心脏湿重和干重、脾脏干重、肺干重、胃湿重和干重、盲肠湿重与海拔呈显著或极显著正相关,而肾湿重、大肠长度与海拔呈负相关;雌性高原鼢鼠心脏湿重和干重、肺脏湿重和干重、胃湿重、盲肠湿重、盲肠长度与海拔呈显著或极显著正相关,肝脏湿重和干重、脾脏干重、肾脏湿重和干重、大肠干重、大肠长度与海拔呈显著或极显著负相关;其他与海拔无显著相关性。研究结果表明,内脏器官与海拔的相关性体现出高原鼢鼠面对不同的生存环境、能量需求、氧气含量、外界病原体等因素做出的代偿性适应。     

横断山区高山姬鼠消化道形态的季节动态

为探讨栖息于横断山地区高山姬鼠的消化道特征与环境之间的适应关系,对野外条件下高山姬鼠消化道各项指标进行了测定.实验分别测定了不同季节高山姬鼠胃、小肠、大肠、盲肠的长度、含内容物重、去内容物重、干组织重.结果表明:高山姬鼠消化道特征存在季节性变化,胃、小肠、大肠的各项指标及盲肠去内容物重、干重均于食物质量较好的6月、9月份较高;盲肠长度和含内容物重于3月、11月份较高.高山姬鼠在低温、食物质量下降、繁殖等胁迫因子影响下,通过增加食物摄入、调节消化道形态来满足能量需求的增加,维持正常的生理机能.高山姬鼠的消化道在不同季节中表现出的变化模式说明其有能力适应低纬度高海拔,年平均温度较低的生存环境.     

高原鼢鼠的消化对策

动物面临不同的生活环境及生活方式,往往采取不同的消化对策,而消化道结构在动物的消化对策中起关键作用。为进一步了解高原鼢鼠的生存对策,比较了高原鼢鼠与大白鼠消化道形态结构与食物摄入量、食物吸收量及食物消化率的差异。结果表明:高原鼢鼠的食物摄入量及食物吸收量显著低于大白鼠,食物消化率、蛋白质消化率及粗纤维消化率显著高于大白鼠。而两种动物的蛋白质吸收量及粗纤维吸收量差异不显著。高原鼢鼠的胃、小肠、大肠、盲肠干重及大肠长度与盲肠长度显著高于大白鼠,小肠长度差异不显著。可见,动物的消化率及能量需求与其消化道形态相适应。高原鼢鼠采取摄取少量的食物、增加消化道长度或重量、提高食物消化率的消化对策。     

高寒草甸3种啮齿类动物消化道器官形态的比较研究

不同动物面对相同或相似的环境压力,采取不同的适应对策,消化器官形态差异能体现各自适应的方式。为进一步了解草食哺乳动物对各自生存环境的适应对策,本文比较了青藏高原高寒草甸3种小型草食哺乳动物的消化道长度及消化道器官指数。结果显示:根田鼠的胃指数高于高原鼢鼠和高原鼠兔,小肠、大肠及盲肠指数均是高原鼠兔高原鼢鼠根田鼠,消化道各部位相对长度均是根田鼠高原鼠兔高原鼢鼠。根田鼠大肠及盲肠长度占消化道总长的比例高于高原鼠兔和高原鼢鼠;小肠占消化道总长的比例最低。结果表明,动物消化道形态的差异可能与食物组成、能量和代谢需求等因素有关。面对不同的环境压力,消化道这种适应性差异是不同物种为适应多变的环境条件进化的结果。     

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     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV     

Mink Circovirus Can Infect Minks,Foxes and Raccoon Dogs

正Dear Editor,Mink circovirus (MiCV), which is clustered in the genus Circovirus of the family Circoviridae, was first described in minks from farms in Dalian, China in 2013 (Lian et al.2014). The complete single-stranded circular genome of the virus is 1,753 nucleotides long and contains two major open reading frames (ORFs), designated ORF1 (Rep gene)and ORF2 (Cap gene)(Lian et al. 2014; Ge et al. 2018).Sequence analysis has shown that MiCV is most closely     

CypA Regulates AIP4-Mediated M1 Ubiquitination of Influenza A Virus

Cyclophilin A (CypA) is a peptidyl-prolyl cis/trans isomerase that interacts with the matrix protein (M1) of influenza A virus (IAV) and restricts virus replication by regulating the ubiquitin–proteasome-mediated degradation of M1. However,the mechanism by which CypA regulates M1 ubiquitination remains unknown. In this study, we reported that E3 ubiquitin ligase AIP4 promoted K48-linked ubiquitination of M1 at K102 and K104, and accelerated ubiquitin–proteasome-mediated degradation of M1. The recombinant IAV with mutant M1 (K102 R/K104 R) could not be rescued, suggesting that the ubiquitination of M1 at K102/K104 was essential for IAV replication. Furthermore, CypA inhibited AIP4-mediated M1 ubiquitination by impairing the interaction between AIP4 and M1. More importantly, both the mutations of M1 (K102 R/K104 R) and CypA inhibited the nuclear export of M1, indicating that CypA regulates the cellular localization of M1 via inhibition of AIP4-mediated M1 ubiquitination at K102 and K104, which results in the reduced replication of IAV.Collectively, our findings reveal a novel ubiquitination-based mechanism by which CypA regulates the replication of IAV.