用主成分分析法分析金翅夜蛾亚科各性状对分类的重要性和性状变异方向

本文在“金翅夜蛾亚科的数值分类研究”的基础上用主成分分析的结果对金翅夜蛾亚科分类的性状做进一步分析,说明各性状对分类的重要性和性状的变异方向,并对用协方差矩阵和相关矩阵进行的主成分分析结果进行比较,说明对本问题（分类指标全是定性指标）适宜用协方差矩阵做主成分分析。     

云南医学革螨数值分类研究

以云南省57种医学革螨作为分类单元,以形态特征为主列出60项分类性状特征来探讨云南省医学革螨不同属和种的亲缘关系。运用SPSS 11.5 统计软件中的系统聚类分析和主成分分析,对57种医学革螨进行了数值分类分析。结果显示：57种医学革螨划分为厉螨科（La elapidae）、寄螨科（Parasitidae）、皮刺螨科（Dermanyssidae）、赫刺螨科（Hirstionyssidae）和裂胸螨科（Aceosejidae）5个类群。赫刺螨属和棘刺螨属从厉螨科中分离出来另立为赫刺螨科,柏氏禽刺螨归入了皮刺螨科而不是巨刺螨科。分类结果与传统形态分类结果基本一致,因而认为数值分类能比较客观地反映医学革螨各分类阶元的分类地位与亲缘关系。     

深红酵母的化学数值分类学研究

对２９株深红酵母（Ｒｈｏｄｏｔｏｒｕｌａｒｕｂｒａ）的裂解气相色谱（ＰｙＧＣ）数据分别采用三种数值分析方法进行化学数值分类学研究,结果显示,不管是聚类分析,主分量分析还是Ｑ型因子分析,均能得到极为相似的分类结果,其中Ｑ型因子分析效果最佳,通过数值分类学研究,２９株深红酵母被划分成不同的四群,其中ＮＫＲ１１１不能与上述四群聚类,作者建议将该菌株从Ｒｈ．ｒｕｂｒａ中分出,仍保留Ｒｈ．ｐｉｌｉｍａｎａｅ     

数量分类在南亚热带丘陵地土壤样本分类上的应用

本文将三种聚类策略和二种排序技术应用于南亚热带丘陵地土壤样本的分类，结果表明，平方和增量法与可变法的聚类结果极为接近，并具有较大的合理性。排序技术以欧氏距离的极点排序效果最好，二维图上距离与原来样本间的欧氏距离的相关系数为０．９５１１．同时．极点排序与聚类结果具有很好的吻合世，而主分量分析则效果不佳。文章认为，结合极点排序与聚类分析可以对该地土壤进行有效的分类，它可以克服在排序图上作直接分类时所存在的各种局限性。文章还探讨了排序效果的检验、排序图上样点的分类、排序图形可能存在的局限以及因子载荷量的意义。     

20种山茶科植物的叶表皮微形态研究

为解决一些山茶科(Theaceae)的分类学问题,该研究在光学显微镜下对山茶科2亚科6属共20种植物的13种叶表皮微形态特征进行了观察,并利用聚类分析和主成分分析对这些特征进行分析,为山茶科的科学分类提供参考资料。结果表明:(1)山茶科20种植物的13种叶表皮微形态特征能够区分种间差异和分类等级,显示了比较全面的分类价值。(2)基于微形态特征的聚类分析和主成分分析结果显示,20个种分为2个大类群以及10个分支,很好地区分了山茶亚科(Theoideae)与厚皮香亚科(Ternstroemoideae),并将大部分分类地位相近的物种归类到一起,较好地反映了物种之间的亲缘关系。(3)该研究结果支持将小黄花茶组(Sect.Luteoflora)作为独立的一个组;支持将重庆山茶(Camellia chungkingensis Chang)从瘤果茶组(Sect.Tuberculata Chang Tax.)中分离;支持将山茶亚科与厚皮香亚科划分为两个较大类群,认为将厚皮香亚科并入五列木科(Pentaphylacaceae)的观点还有待更多实验证据的支持。     

瑞香属和荛花属的数量分类研究

瑞香属和荛花属为瑞香科瑞香亚科的落叶或常绿灌木,中国西南部是瑞香属和荛花属的重要分化中心。全世界共有瑞香属95种、荛花属70种,中国分布有瑞香属52种、荛花属49种。瑞香属和荛花属的分类学研究一直存在不同程度的分歧。花盘形状和果实类型在传统分类中一直是区分瑞香属和荛花属的典型特征,而花盘形态和果实类型在2个属中存在交叉和过渡,部分植物分类学家根据这些特征将两个属进行过不同程度的归并。该研究采用数量分类法对瑞香属77种(变种)和荛花属62种(变种)植物,选取32个形态学性状进行聚类分析和主成分分析。结果表明:聚类分析和主成分分析均显示两属均未形成单系类群。在主成分分析中,前3个主成分分析的贡献值为35.56%,传统分类中用来区分两属的花盘形状、叶序及果实类型等特征对前3个主成分贡献相对较小,因此,传统分类学中对这两个属进行区分的性状并没有典型的分类学意义。同时,聚类图和主成分分析得到的散点图均不能将这两个属区分开来。数量分类研究结果显示两属植物存在明显的交叉,支持瑞香属和荛花属不是两个独立自然类群的观点。     

中国白蛉亚科数值分类研究（双翅目: 毛蠓科）

【目的】 对中国白蛉亚科（Phlebotominae）昆虫进行数值分类研究, 探索其在系统发育过程中的亲缘关系。【方法】 选取中国白蛉40个蛉种作为分类单元以及白蛉的68项形态特征为分类指标, 进行系统聚类分析。【结果】 聚类分析结果与传统属级及白蛉属Phlebotomus的亚属级分类一致。司蛉属Sergentomyia的亚属分类与传统分类有一些区别, 聚类分析将司蛉属分为8类, 其中尼克组nicnic group与司蛉亚属subgenus Sergentomyia和传统分类一致; 泉州司蛉S. quanzhouensis和唐氏司蛉S. tangi聚入帕蛉亚属subgenus Parrotomyia; 尹氏司蛉S. yini聚入新蛉亚属subgenus Neophlebotomus, 应氏司蛉S. iyengari、马来司蛉S. malayensis、吐鲁番司蛉S. turfanensis、兰州司蛉S. lanzhouensis和南京司蛉S. nankingensis聚为一类; 歌乐山司蛉S. koloshanensis、方亮司蛉S. fanglianensis和云南司蛉S. yunnanensis与尼克组nicnic group聚成一类, 此类群和此属中其他蛉种系统发育关系距离远。【结论】 中国白蛉亚科昆虫的聚类分析结果与传统分类基本一致, 验证了传统分类系统的可靠性, 并揭示了传统分类中一些蛉种不确定分类问题。司蛉属聚类分析结果与传统分类有差别, 提示有个别蛉种需重新考虑其分类地位。     

深红酵母的化学数值分类学研究

对29株深红酵母(Rhodotorula rubra)的裂解气相色谱(PyGC)数据分别采用三种数值分析方法进行化学数值分类学研究。结果显示,不管是聚类分析、主分量分析还是Q型因 子分析,均能得到极为相似的分类结果,其中Q型因子分析效果最佳。通过数值分类学研究,29株深红酵母被划分成不同的四群,其中NKRlll不能与上述四群聚类,作者建议将该菌株从Rh. Rubra中分出,仍保留Rh. pilimanaE种名。     

中国木兰亚科植物的主要分类性状观察

对木兰亚科植物花的着生式样、心皮中的胚珠数目和花的性别等主要分类性状进行了研究。在毛果含笑、云南含笑等含笑属植物中观察到了顶生花。含笑属的聚伞花序不是一个花序,而是一个具有多花的枝条,其“总花梗”实质上是一个枝条,其节上的花顶生于次级侧枝上,属于顶生花式样。山玉兰和盖裂木每心皮中的胚珠数目为2～7个,而不是2个。在山玉兰、黄兰、合果木等植物上观察到了单性雄花,而在云南拟单性木兰的雄株上观察到了少数具有1～8个心皮的两性花。根据观察结果,本文讨论了这3个主要分类性状在木兰亚科分类系统中的意义,并对现有分类系统进行了分析,在此基础上对中国木兰亚科的分类系统做了修订,依据分枝式样、花药的开裂方式,将中国木兰亚科植物归并为木兰属和含笑属。     

中国栎属植物的数量分类研究

在全面衡量中国栎属49种4变种性状特征的基础上,观测了25个定性性状和18个数量性状。通过聚类分析,可以将中国栎属分为5个特征明显的表征群,即5组:麻栎组(Section Aegilops)、槲栎组(Section Quercus)、高山栎组(Section Brachylepides)、巴东栎组(Section Engleriana)和橿子栎组(Section Echinolepides)。在主成分分析中,虽然性状的累积贡献率增长不明显,前3个主成分累积贡献率仅有50.4%,但结果仍然显示出和聚类分析同样的结果。说明栎属的分类性状仍存在主要方面,只不过在演化过程中由于性状变异的多样性,产生了多个不同的表征类群。分析结果对我们解决个别有疑问种的分类地位也有启示作用。因此,数量分类方法对解决栎属组间及种间的分类问题有重要的意义。     

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.