鄱阳湖区獐种群生存力分析

鄱阳湖区的獐种群是一个孤立的种群,近年来其数量急剧减少。本研究应用种群生存力分析的原理和方法,利用漩涡模型预测了鄱阳湖区獐种群在未来100 a内的种群变动趋势,并分析了不同场景下獐种群的变化趋势。结果表明:鄱阳湖区獐种群在未来100 a灭绝的概率是0.37。如果鄱阳湖区獐的栖息地进一步被破坏,獐种群的灭绝概率将大幅度增加;高概率的幼仔死亡率会使獐种群在未来100 a出现灭绝的概率为100%;灾害对种群的影响也很大,在洪灾和狩猎的双重作用下,洪灾发生频率增加将使獐种群灭绝概率增大。通过本次对鄱阳湖区獐的种群生存力分析,发现幼仔的死亡率和栖息地的破碎化是鄱阳湖区獐种群的重要制约因素,建议在獐栖息地之间设立生态走廊,加大对偷猎的打击力度,将有利于该地区獐种群的长期发展。     

江苏沿海獐种群的现状和栖息地的利用

盐城沿海獐分布的北限为射阳和滨海县交界的扁担河口,南限以如东和海安交界的北凌港闸为界。分属射阳、大丰、东台、海安４县,该区域中獐种群已被隔离成几个小种群。现存数量估计为８５０—１５２３头。种群的季节波动很大,繁殖前后种群数量相差近一倍。野外种群性比平均为♀：♂＝１００：７７．３。成幼比＝１．１９：１．００;８月份调查,平均每头母獐育仔１．５３头。该分布区獐喜欢选择有斑块状高草相嵌的矮草草滩栖息。盐城地区獐数量因滩涂围垦和开发而急速下降,急需采取有力对策加以保护。     

生境丧失对具有似Allee效应集合种群的影响及对策——以江苏盐城为例

似Allee效应对物种续存是潜在的扰动因素,稀有物种更易受其影响,可能增加生存于破碎化栖息地中的珍稀物种的死亡风险;但似Allee效应对多物种集合种群续存的影响及其在珍稀物种保护中的应用未能引起足够重视。将似Allee效应引入集合种群动力模式,建立了生境丧失下具有似Allee效应的n-珍稀物种的集合种群模式,并以江苏盐城滩涂湿地中的29种珍稀物种为研究实例。研究结果表明:(1)似Allee效应导致n-物种集合种群多度作长期变周期振荡,原本竞争共存物种可能无法继续共存,甚至灭绝。(2)似Allee效应增强对次强种及劣势种的生存极为不利,导致次强物种由强至弱灭绝,劣势物种由弱至强依次灭绝。(3)盐城天然湿地丧失29%后,11种劣势物种的集合种群由弱到强将最终依次灭绝,灭绝迟豫时间为304～890a,这些物种即Hanski所指的"活死者"。(4)适度增加栖息地面积是保护珍稀物种多样性的有效方法之一,在盐城现存3200km2的天然湿地基础上适度增加1801～2064km2左右栖息地面积,可以有效保护29种濒危物种的多样性,同时应注意结合针对具体物种的保护措施来提高濒危物种多度。研究结果对物种多样性保护及自然保护区建设具有重要的理论指导意义。     

江苏盐城自然保护区獐栖息地的质量评价

本研究通过1999 年3 月至2000 年11 月期间的实地调查,利用地理信息系统(GIS)对江苏省盐城自然保护区及周边地区獐在产仔前期、产仔期以及产仔后期栖息地适宜性进行了评价,并对理想状况下獐的潜在栖息地和实际栖息地的范围及分布进行了比较。理想状况下3 个不同时期獐的最适宜栖息地面积分别为361.0 km² 、267. 5 km² 和338. 5 km², 主要分布在保护区核心区、东台市琼港镇南的新东乡滩涂;而实际在各个时期獐的最适宜栖息地面积只有44.75 km² 、36.00 km² 和54. 50 km² ,仅为潜在栖息地的1/7 左右。通过比较獐的潜在栖息地与实际栖息地的综合适宜性指数发现,整个研究地区适合獐生存的栖息地非常少,最适宜栖息地的面积不到总面积的1%,而不适宜的栖息地面积却达到40%,其余大部分均是次适宜的栖息地。由于獐的栖息地受到道路和居民等人为活动的影响,导致大量适宜栖息地丧失。为了有效地保护盐城保护区及周边地区的獐种群,建议减少对滩涂的各种开发活动,保护现有的适宜栖息地,引导当地居民合理利用滩涂资源。     

马边大风顶自然保护区大熊猫种群生存力模拟分析

采用漩涡模型Vortex mondel 713 , 模拟了马边大风顶自然保护区大熊猫种群在未来100年内的变动趋势。结果显示: 在无交配限制、无密度制约、无近亲交配衰退等条件下, 马边大风顶自然保护区大熊猫种群数量呈下降趋势; 在考虑近交衰退的影响后, 遗传多样性水平降低, 灭绝率提高; 竹子开花虽能加速大熊猫种群的绝灭, 但由于保护区分布有多个竹种,因此并不会对大熊猫种群产生灾难性影响; 但是人为捕杀可迅速减少大熊猫种群数量, 加速其灭绝过程。因此, 对该保护区大熊猫进行保护的最重要措施就是严格控制人为捕杀, 并保护栖息地及走廊带。     

人类活动和滩涂变迁对苏北沿海地区獐分布的影响

结合查阅历史资料,访问当地群众和实地调查等方法,对獐在江苏沿海的历史分布以及人类活动和滩涂变迁对其分布的影响进行了研究。历史上,江苏沿海地区有大量适合獐生存的草滩,尤其是1128年黄河夺淮后,使江苏沿海的滩涂迅速淤涨,形成了大面积的适合獐生存的草滩。1855年黄河北归以后,滩涂淤涨减少,本世纪初开始,随着人类对滩涂围垦和开发的强度日益增加,獐分布面积日益减少。近20年来,獐的分布区开始破碎。目前,江苏沿海獐的分布已分裂为4个面积不足100km2的小区,如没有有效的措施保护獐的栖息地,该地区獐的灭绝将不可避免。     

走私赛加羚羊角案例

赛加羚羊是一种神奇的野生动物,现存2个亚种。其中俄罗斯亚种在第一次世界大战结束时仅剩1000只,至二战结束时恢复到9万只,到20世纪60年代上升到130万只以上,但目前又下降到10万只左右。在我国已经灭绝的可能是赛加羚羊蒙古亚种,该亚种在蒙古国的现存野生种群估计只有数百头。导致赛加羚羊野生种群大幅变动的原因很多,首当其冲的应该是赛加羚羊对气候变化的适应性较差。该物种的栖息地通常人烟稀少,气候寒冷,植被覆盖率较差,一旦遭遇持     

污染土壤中多环芳烃生物降解的调控研究

选用温度、湿度、表面活性剂ＴＷ８０和ＣＮＰ比４个因素为调控因子,采用正交法进行周期为１５０天的实验研究．结果表明,３０天后,土壤中ＰＡＨｓ的降解率可达４４．５～７４．６％,６０天后,达７０．４～９３．７％,降解率的不同与调控条件显著相关．在此期间,降解最佳条件为４０℃,湿度２５％,ＣＮＰ比为１２０１０１,ＴＷ８０分别为２００～５００ｍｇ·ｋｇ－１．实验结束时,土壤中ＰＡＨｓ的降解率达９１．２～９９．８％．降解的最佳条件是４０℃,湿度１５％．经Ｒ值判别表明,不同时期各因子对ＰＡＨｓ降解影响有所不同．温度对ＰＡＨｓ降解影响较大,表面活性剂对土壤中ＰＡＨｓ的生物降解有调控作用．     

漩涡模型及其在白暨豚种群管理中的应用

漩涡模型作为一种用于野生动物种群生存力分析的计算机模拟工具,已在濒危物种的保护和管理方面得到了广泛的应用。本文介绍了漩涡模型的产生和特征,同时使用这一模型完成了长江中白暨豚（Ｌｉｐｏｔｅｓｖｅｘｉｌｌｉｆｅｒ）种群生存力分析。模拟的结果表明,在未来１００年内,白暨豚在高、中死亡率的条件下,种群灭绝概率分别为１．０和０．５左右。但是,在死亡率低和极低的条件下,白暨豚的灭绝过程可能持续１００年以上,或永远也不会灭绝。开始种群大小对白暨豚的平均灭绝时间有一定的影响,但对种群生长率（ｒ）却没有影响。在高、中、和低死亡率条件下,白暨豚种群生长率分别为－０．０７、－０．０４和－０．０２。     

滇金丝猴（Rhinopithecusbieti）现状及其保护对策研究

滇金丝猴（Ｒｈｉｎｏｐｉｔｈｅｃｕｓｂｉｅｔｉ）是我国特有的珍稀濒危动物,生活在海拔３８００～４３００ｍ的原始冷杉林中,但有时也会在４３００～４７００ｍ的低矮灌丛、草甸和流石滩上活动达数小时之久,甚至能跨越近千米的无林高海拔地带,因而它们是海拔分布最高的非人灵长类。松萝是它们的主要食物,取食松萝的时间占总取食时间的９１％。猴群活动范围可达近百平方公里。笔者在历时８年的野外考察中,已查明这一物种的全部现存自然种群只有１３个,分布在云南的德钦、兰坪、潍西、丽江和西藏的芒康这五县境内,其现存种群数量为１０００～１５００只;所有现存自然种群几乎均处在相互隔离的状态,群间已不可能进行基因交流,充分表明它们已到达灭绝边缘。然而其栖息地内的商业伐木规模仍在继续扩大,周围的人口压力正在不断增加,各猴群均面临不同程度的偷猎压力。这一现状委实令人担忧。如何拯救这一“国宝”应引起我国保护学家和各级政府有关职能部门的重视     

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     

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