南亚果实蝇各虫态发育历期及有效积温研究

【背景】南亚果实蝇是世界性的检疫性害虫,在我国多个省市发生为害,对瓜果作物造成了严重的经济损失。【方法】采用人工恒温饲养方法,分别设置10、14、18、22、26、30、34℃7个恒温条件,测定不同温度条件下南亚果实蝇卵、幼虫和蛹的生长发育历期,并推算出相应的发育起点温度和有效积温。【结果】南亚果实蝇卵、幼虫和蛹的发育起点温度分别为7．36、2．43、7．64℃,卵期、幼虫期和蛹期的有效积温分别为20．21、187．69和156．65日度。完成整个世代的发育起点温度是7．64℃,有效积温为364．55日度。当温度达到34℃时,卵的发育历期相对延长,而蛹则不能正常发育,无法羽化为成虫。【结论与意义】在10～30℃,南亚果实蝇的卵、幼虫和蛹的发育历期随温度升高而缩短,各虫态的发育速率和温度呈显著正相关;在26和30℃下,卵、幼虫和蛹的发育历期均显著短于其他各处理温度的发育历期。该试验结果为了解南亚果实蝇的发育温度极限和进一步开展该害虫的适生性分析提供了基础信息,进而为制定该虫的检疫措施提供依据。     

核桃扁叶甲的发育起点温度和有效积温

室内观察测定5个恒温条件下,核桃扁叶甲Gastrolina depressa Baly各虫态的发育历期及起点温度和有效积温。结果表明:在16～32℃温度范围内,核桃扁叶甲均能完成发育,其发育历期随温度的升高而缩短,卵期、幼虫期、蛹期、产卵前期的发育起点温度分别为9.4,12.2,14.3和11.1℃,有效积温分别为43.2,77.2,36.0和104.7日.度;整个世代的发育起点温度为12.0℃,有效积温为260.5日.度。持续过高温度不适合核桃扁叶甲的生长发育。     

温度对红珠凤蝶小斑亚种发育的影响

室内研究了红珠凤蝶小斑亚种Pachliopta aristolochiae adaeus(Rothschild)在19～31℃范围内5个恒温条件下的发育.结果表明,成虫在19℃时不能交配和产卵,而卵、幼虫和蛹在19～31℃范围内均能完成发育,且发育历期随温度而变化.各温度下,预蛹期最短,幼虫期最长,幼虫龄期随虫龄的增加...     

温度对红点唇瓢虫实验种群的影响

在７种温度下测定了红点唇瓢虫（Ｃｈｉｌｏｃｏｒｕｓ ｋｕｗａｎａｅ Ｓｉｌｖｅｓｔｒｉ）发育速率,并求得各虫态的发育起点温度和有效积温。其发育速率与温度的关系能很好地用王如松等（１９８２）提出的模型进行拟合。由此模型估计出最低、最高临界温度和最适发育温度,分别为１０．４２－１３．０１－℃、℃３３．５３－３７．０３℃和２４．９９－３０．１２℃。卵期忍耐温度变化的能力最强。４龄幼虫最弱。温度明显地影响     

温度对美洲斑潜蝇发育、存活和繁殖的影响

在恒温１５,２０,２５,３０和３５℃下,对美洲斑潜蝇在菜豆上的发育和繁殖做了研究。结果表明,在１５￣３５℃范围内,未成熟期各虫态（卵、幼虫和蛹）的发育历期随温度的升高而缩短,发育速率呈逻辑斯蒂曲线变化;卵期孵化率在２５℃中最高;各温度下幼虫期存活率最高,低温１５℃和高温３５℃对蛹的存活有显示抑制作用,１５℃时蛹的死亡率达３９．６％。成虫寿命一般在２０ｄ以内,与温度呈直线负相关;繁殖力最高可达２８１     

变温和恒温对沙葱萤叶甲发育速率的影响

沙葱萤叶甲为近年来在内蒙古草原猖獗成灾的新害虫,为明确温度对其发育速率的影响,分别设置5个变温组合(8/20℃,11/23℃,14/26℃,17/29℃和20/32℃)和6个恒温(13℃,17℃,21℃,25℃,29℃和33℃),比较了变温和恒温对沙葱萤叶甲幼虫和蛹发育速率的影响。结果表明,不同变温组合和恒温对沙葱萤叶甲幼虫和蛹的发育速率有显著的影响。发育历期随温度的升高而缩短,在变温条件下,1龄幼虫期、2龄幼虫期、3龄幼虫期、总幼虫期和蛹期分别从最低温度组合(8/20℃,平均15℃)的11.00,13.44,23.18,46.42和16.89 d,缩短至最高温度组合(20/32℃,平均27℃)的4.92,4.63,9.17,17.83和5.83 d;在恒温条件下,13℃下幼虫不能发育和存活,1龄幼虫期、2龄幼虫期、3龄幼虫期、总幼虫期和蛹期分别从17℃的14.50,10.75,20.63,45.50和11.00 d,缩短至33℃的6.10,5.47,10.60,22.17和5.33 d。在变温条件下,幼虫和蛹的发育起点温度分别为7.44℃和8.48℃,有效积温分别为344.82日度和113.52日度;在恒温条件下,幼虫和蛹的发育起点温度分别为0.64℃和5.11℃,有效积温分别为714.28日度和147.06日度。变温促进了沙葱萤叶甲幼虫和蛹的发育,本研究结果为沙葱萤叶甲的预测预报及综合防控提供了科学依据。     

不同温度对三叶虫萤卵孵化和初孵幼虫发育的影响

本文研究了三叶虫萤Emeia pseudosauteri在不同恒温设置和室内变温条件下卵孵化率和初孵幼虫存活率,并通过直接最优法和直线回归法计算出了三叶虫萤卵的发育起点温度和有效积温。结果表明:12~30℃恒温条件下,卵的孵化率随着温度升高显著下降(P<0.05),且均低于室内变温条件(P<0.05)下的孵化率;初孵幼虫在恒温15℃下的存活率最高,为73.13%;低于12℃和高于30℃恒温中初孵幼虫均无法存活;在恒温条件12~30℃下,卵的发育历期随温度升高而缩短,其中恒温12℃下最长,发育历期为42.96 d(n=3),恒温30℃下最短,发育历期仅12.75 d(n=3)。通过直接最优法计算出三叶虫萤卵的发育起点温度为3.52℃,有效积温分别为382.20 d·℃。上述结果为三叶虫萤的人工繁育提供了参考。     

温度对桔小实蝇种群发育的影响

采用室内人工饲养,研究了温度对外来入侵无锡地区的桔小实蝇(Bactrocera dorsalis)发育的影响。结果表明：17℃～33℃桔小实蝇各虫态发育速率逐渐增加;通过直线回归模型与直接最优法,得出桔小实蝇从卵期到成虫期的发育起点温度为9.9 ℃,卵、幼虫和蛹发育所需温度分别为10.5 ℃、9.6 ℃和10.3 ℃;卵期发育到成虫期的有效积温为381.0 d·℃,卵期、幼虫期和蛹期分别为24.1、178.6和176.7 d·℃。此外,温度影响桔小实蝇各虫态的存活率;25 ℃下卵期的存活率最高,而17 ℃下蛹期的存活率最低。温度对桔小实蝇雌雄性比也有一定影响,以25 ℃下雌虫比率最高。     

温湿度对秃病蚤蒙冀亚种发育的影响

试验表明:在相对湿度为76％、温度在17～29℃范围内,蚤的发育速度随温度升高而加快。35℃时对成蚤前各虫态均具有较强的致死作用。11℃时蚤在57.4天内完成了卵和幼虫期的发育,前蛹期发育了70天以上仍未蜕皮成蛹,但在升温(23℃)70天后仍可羽化。在17、23和29℃时成长率分别为57％、84％和44％。在温度为23℃,相对湿度低于53％时蚤不能完成幼虫期发育。相对湿度为100％时因霉菌污染而使幼虫死亡。湿度对孵化率、幼虫发育历期及成蚤的大小、寿命具有一定的影响。该蚤的最适发育温度在23℃左右,相对湿度在87％左右。     

温度对桃蛀螟生长发育和繁殖的影响

为了明确温度对桃蛀螟Conogethes punctiferalis (Guenée)生长发育和繁殖的影响, 本实验在恒温条件（15, 19, 23, 27和31℃共5个温度梯度）下, 以板栗为寄主食料, 研究了温度对桃蛀螟实验种群生长发育和繁殖的影响。结果表明： 温度对桃蛀螟各虫态的发育历期、 存活率、 蛹重以及种群繁殖力有显著影响。在15~27℃范围内, 各虫态的发育历期均随温度的升高而缩短, 发育速率与温度呈显著正相关。但是, 当温度上升至31℃时, 幼虫生长发育受到抑制, 其发育历期比27℃时延长了1.11 d, 而卵期、 蛹期和产卵前期仍符合随温度升高趋于缩短的趋势。此外, 15℃下桃蛀螟5龄幼虫发育停滞, 表明老熟幼虫的发育起点温度高于其他低龄幼虫。桃蛀螟世代存活率随环境温度变化的大小顺序为23℃>27℃>19℃>31℃, 其中, 23~27℃的存活率较高, 为54.44%~63.56%, 31℃时为4.30%, 说明温度过高或过低均不利于其生长发育。成虫产卵量在23℃时最高, 单雌平均产卵量达55.00粒, 其次为19℃和27℃, 单雌平均产卵量分别为43.30和39.70粒; 31℃下产卵量最少, 仅为20.90粒。由直接最优法计算得到桃蛀螟卵期、 幼虫期、 蛹期、 产卵前期及全世代的发育起点温度分别为10.37, 10.06, 14.27, 7.47和11.85℃, 有效积温依次为70.84, 287.71, 118.42, 58.33和509.06日度。研究结果为桃蛀螟发生期的预测预报提供了基础参考数据, 对指导生产实践有实际的应用意义。     

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.