不同温度下白蜡虫花翅跳小蜂的实验种群生命表

在15、18、21、24、27和30℃恒温下,观察了温度对白蜡虫花翅跳小蜂Microterys ericeri发育、存活和繁殖力的影响,组建了相应温度下的实验种群生命表。白蜡虫花翅跳小蜂全代的发育起点温度和有效积温分别为12.1℃和499.4日·度。27℃时发育历期最短,产卵量、产卵率和卵孵化率最高。24℃时雌虫怀卵量最多,3～5龄幼虫和蛹的存活率最高。6种温度下白蜡虫花翅跳小蜂种群的世代存活率分别为8.5%、25.2%、50.3%、68.2%、49.8%和38.1%。24℃时世代存活率、种群趋势指数、净增殖率和内禀增长力均高于其它温度处理。24℃和27℃时种群加倍时间只需12天。18℃时种群出现负增长,15℃时白蜡虫花翅跳小蜂不产卵,不能繁殖下一代。     

低温对副珠蜡蚧阔柄跳小蜂发育及繁殖的影响

副珠蜡蚧阔柄跳小蜂是橡副珠蜡蚧的重要寄生蜂。为了探明副珠蜡蚧阔柄跳小蜂对低温的适应性,本文在15℃-24℃范围内对该蜂的产卵、发育、出蜂量及性比进行观察。结果表明:副珠蜡蚧阔本跳小蜂在15℃-24℃范围内,随温度的升高,产卵量逐渐增加;该蜂在21℃、24℃时蜂能完成世代发育,在15℃、18℃时少量跳小蜂能发育到蛹,但均不能羽化为成蜂;温度对性比的影响明显,24℃的雌性比例高于21℃。综上所述,副珠蜡蚧阔柄跳小蜂对18℃以下的低温适应性较差,室内繁殖或野外放蜂时注意选择较高的温度条件。     

白蜡虫及其3种优势寄生蜂的时空生态位

在白蜡虫Ericerus pela (Chavannes)分布特征和寄生蜂调查的基础上,分析了白蜡虫及其3种优势寄生蜂:白蜡虫花翅跳小蜂Microterys ericeri Ishii、中华花翅跳小蜂M.sinicus Jiang和白蜡虫阔柄跳小蜂Metaphycus ericeri Xu et Jiang的时间和空间的一维生态位宽度、生态位重叠和比例相似性。结果表明,白蜡虫及其3种优势寄生蜂的时间生态位宽度:白蜡虫>白蜡虫阔柄跳小蜂>白蜡虫花翅跳小蜂>中华花翅跳小蜂,空间生态位宽度:白蜡虫>白蜡虫花翅跳小蜂>白蜡虫阔柄跳小蜂>中华花翅跳小蜂。3种优势寄生蜂与白蜡虫的生态位重叠度:白蜡虫花翅跳小蜂>中华花翅跳小蜂>白蜡虫阔柄跳小蜂,比例相似性:白蜡虫花翅跳小蜂>白蜡虫阔柄跳小蜂>中华花翅跳小蜂。说明白蜡虫花翅跳小蜂与白蜡虫在资源序列上分布的相似性最大,在时间上的同步性和空间上的同域性较强,资源利用程度最高。白蜡虫花翅跳小蜂与白蜡虫阔柄跳小蜂在时间生态位、空间生态位和时间-空间生态位上均有较大的重叠和比例相似性,在资源利用上存在明显的种间竞争。白蜡虫种群数量大,生长周期长、为多种寄生蜂的繁育提供了丰富、稳定的食物资源。     

白蜡虫啮小蜂对白蜡虫花翅跳小蜂种群控制作用的研究

研究了白蜡虫啮小蜂TetrastichuskodaikanalensisSaraswat的室内饲养条件及其对白蜡虫花翅跳小蜂MicroterysericeriIshii的控制作用。研究结果表明 ,温度对白蜡虫啮小蜂存活率和产卵量有显著影响。 1 8、 2 1、2 4、 2 7、 30和 33℃ 6个温度处理下 ,白蜡虫啮小蜂的世代存活率分别为 1 84%、 31 83%、 80 39%、 72 75 %、48 0 8%和 2 2 81 %。 30℃时每雌产卵量和产卵百分率最高 ,分别为 1 3 2 1粒和 84 84%。雄蜡虫体内的白蜡虫啮小蜂有 3个羽化高峰期 ,分别为 6月下旬、 8月上～中旬和 9月中～下旬 ;雌蜡虫体内白蜡虫啮小蜂的 3个羽化高峰期为 8月上～中旬、 9月中～下旬和 1 0月下旬～ 1 1月上旬。白蜡虫啮小蜂的第 3个高峰种群数量最大 ,对白蜡虫花翅跳小蜂的重寄生率最高。第 3、 4代啮小蜂对寄生于雌雄蜡虫体内的白蜡虫花翅跳小蜂的重寄生率分别为雌蜡虫体内 :48 78%和 5 4 6 6 % ,雄蜡虫体内 :5 6 6 6 %和 6 4 71 % ;第 5代的重寄生率达76 0 0 % ;各代的重寄生率均为 4龄幼虫 >5龄幼虫 >蛹。人工释放啮小蜂对白蜡虫花翅跳小蜂种群数量有显著的控制作用。每株女贞树放 30头白蜡虫啮小蜂蛹 1次或 2次 ,白蜡产量分别为 1 1 1 3g和 1 37 6g ,为对照的3 0 6倍和 3 78倍。种虫产量分别为 1 49     

副珠蜡蚧阔柄跳小蜂对橡副珠蜡蚧的控制作用

在实验室条件下,研究了副珠蜡蚧阔柄跳小蜂对橡副珠蜡蚧的控制作用.结果表明:该蜂的寄生功能反应符合Holling Ⅱ型方程,但各温度间功能反应的参数存在差异,以瞬时攻击率/捕食处理时间(a/Th)为评价指标,在30℃捕食效能最强,a/Th 为23.4211.副珠蜡蚧阔柄跳小蜂的寄生功能反应有较强的种内干扰作用,随着自身密度的增加,寄生数量逐渐减少,在温度21℃～33℃范围内,Hassell(1969)模型E=QP-m均能较好地反映副珠蜡蚧阔柄跳小蜂的寻找效应与其自身密度之间的关系;在21℃～27℃,随着温度的上升干扰作用增强,27℃时干扰系数最大(0.6626),温度上升至30℃、33℃时干扰作用略有下降,分别为0.6161、0.5916.副珠蜡蚧阔柄跳小蜂对产卵前期的橡副珠蜡蚧成虫控制效果好,寄生后能完全控制,有少量幼虫爬出的橡副珠蜡蚧被寄生后,控制效果下降至81.4%.     

白蜡虫阔柄跳小蜂生物学特性的研究

白蜡虫阔柄跳小蜂Metaphycus ericeri Xu et Jiang在昆明地区一年发生5代,以3、4、5龄幼虫和蛹在白蜡虫雌成虫体内越冬。该蜂的发育起点温度和有效积温分别为11.45℃和552.93日度。18 ℃、21℃、24℃、27℃和30℃恒温条件下的平均世代历期分别为 66.87天、42.27天、35.56天 、30.84天和27.81天。成虫需取食蜜露或白蜡虫雌虫体液作补充营养。性比为1.75～2.88:1(平均2.25:1)。产卵前期2～3天。开始产卵后的2～5天产卵量占总产卵量的62.21%。 27℃的产卵量和产卵率分别为19.31粒和89.81%。18℃时仅4.37粒和18.56%。15℃时不产卵。补充营养、性别和产卵与否对成虫寿命有显著影响。幼虫共5龄。1～4龄以寄主体液和组织为食。5龄幼虫不取食,3～4天后化蛹。     

温度对副珠蜡蚧阔柄跳小蜂发育和繁殖的影响

通过观察副珠蜡蚧阔柄跳小蜂Metaphycus parasaissetiae Zhang and Huang在18,21,24,27,30,33和36℃恒温条件下的生长发育情况,求得其世代发育起点温度和世代有效积温分别为13.10℃和215.00日.度,建立世代发育历期预测式为N=[215.00±44.32]/[T-(13.10±3.24)],世代发育速率与温度之间的关系拟合为S形曲线V=-e(1.33+37.73/T),推算出该蜂在海南1年可发生18代。所设试验温度范围内,该蜂对橡副珠蜡蚧Parasaissetia nigra(Nietner)的寄生率在13.33%～20.00%范围内波动,30℃时寄生率最高;雌性比率在27℃时最大为70.03%。随着试验温度的升高,成蜂羽化相对集中,羽化持续时间逐渐缩短,羽化高峰提前。30℃条件下雌蜂终生产卵量最多,平均25.77粒。雌蜂寿命随试验温度的升高而逐渐缩短,同一恒温条件下补充20%蜂蜜水可显著延长雌蜂寿命。27～30℃可视为有利于副珠蜡蚧阔柄跳小蜂发育繁殖的适温范围,最适温度为30℃。     

白蜡虫啮小蜂对白蜡白花翅跳小蜂种群控制作用的研究

研究了白蜡虫啮小蜂Ｔｅｔｒａｓｔｉｃｈｕｓ ｋｏｄａｉｋａｎａｌｅｎｓｉｓ Ｓａｒａｓｗａｔ的室内饲养条件及其对白蜡虫花翅跳小蜂Ｍｉｃｒｏｔｅｒｙｓ ｅｒｉｃｅｒｉ Ｉｓｈｉｉ的控制作用。结果表明,温度对白蜡虫啮小蜂存活率和产卵量有显著影响。１８、２１、２４、２７、３０和３３℃６个温度处理下,白蜡虫啮小蜂的世代存活率分别为１３．２１％粒和８４．８４％。雄蜡早体内的白蜡虫啮小蜂有３个羽化高峰期,分别     

中华花翅跳小蜂生物学特性和种群动态的研究

中华花翅跳小蜂Microterys sinicus Jiang是白蜡虫成虫产卵期的主要天敌。该蜂成虫喜在自然光下活动,取食和交配都在寄主树上进行。中华花翅跳小蜂每雌平均怀卵量34.39粒,产卵前期2～3天。产卵量、产卵率和产卵天数与温度密切相关,27℃时产卵量和产卵率最高。30℃时产卵天数最少。21～27℃卵孵化率达80%以上。幼虫共5龄。每头跳小蜂幼虫平均取食蜡虫卵数分别为：1龄14.6粒,2龄29.8粒,3龄69.4粒,4龄126.9粒。5龄幼虫不取食。全代发育起点温度和有效积温分别为11.84℃和574.32日·度。补充营养能显著延长成虫寿命和产卵天数,提高雌虫产卵量。中华花翅跳小蜂成虫在田间有两个高峰期,分别发生在4月上中旬和5月中下旬。每粒虫囊内跳小蜂幼虫数与白蜡虫健卵百分率呈负指数关系,拟合方程为：Y=96.0829Exp(-0.1872x)。     

副珠蜡蚧阔柄跳小蜂的寄生影响因子

副珠蜡蚧阔柄跳小蜂Metaphycus parasaissetiae是橡副珠蜡蚧Parasaissetia nigra成虫的重要内寄生蜂。寄生蜂的寄生效果受多种因素影响,就温度、光周期、寄主成虫日龄、雌蜂日龄及交配等因子对副珠蜡蚧阔柄跳小蜂的寄生率、每头寄主的出蜂量及后代雌性率的影响进行研究,以期探明几种因子对该蜂寄生效果的影响。结果表明:温度为27—30℃时寄生率最高为91.7%,出蜂量以27℃最高为7.5头,雌性率以24℃条件最高为72.1%,其次27℃为62.6%,说明24—30℃是寄生效果较好的适温范围;光周期对副珠蜡蚧阔柄跳小蜂的影响明显,光暗比为12 h∶12 h条件下,其寄生率、出蜂量、后代雌性率均最大,分别为70.6%、5.3头、68.3%;副珠蜡蚧阔柄跳小蜂寄生用20—21日龄橡副珠蜡蚧成虫的寄生率、出蜂量及后代雌性率均为最高,分别为87.0%、5.6头、51.2%,说明20—21日龄的橡副珠蜡蚧成虫是副珠蜡蚧阔柄跳小蜂最适合寄生的阶段;雌蜂日龄对寄生效果的影响明显,3日龄的出蜂量最多为5.6头,4日龄的小蜂寄生率最高为81.7%,5日龄的雌性率最大为55.2%;交配是另一影响寄生效果及性比的重要因子,已交配的寄生率及出蜂量显著高于未交配的,分别为91.7%、7.5头,交配的雌性率为62.1%,而未交配所育后代均为雄蜂。综合以上结果分析,可考虑选用20—21日龄橡副珠蜡蚧成虫、充分交配的3—6日龄小蜂、温度27℃及光周期L∶D=12∶12作为室内扩繁副珠蜡蚧阔柄跳小蜂的理想条件组合。     

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