疟原虫一新种—偏核疟原虫（真球虫目：疟原虫科）

作者在广州市郊检查家麻雀的血寄生原虫时,发现疟原虫属一新种。本新种为鸟类的齐奥虫亚属疟原虫,在世界上首次报告。模式标本保存在中山大学生物系寄生虫学研究室。     

鸟疟原虫一新种—竹鸡疟原虫的记述（孢子纲：疟原虫科）

本文描述采自粤北灰胸竹鸡Ｂａｍｂｕｓｉｃｏｌａ ｔｈｏｒａｃｉｃａ的一种小型疟原虫,该虫与近似种海南联核疟原虫Ｐ．ｊｕｘｔａｎｕｃｌｅａｒｅ甚接近,但存在显著的差别,经鉴定为诺维虫亚属Ｎｏｖｙｅｌｌａ中一新种,即竹鸡疟原虫Ｐｌａｓｍｏｄｉｕｍ（Ｎｏｖｙｅｌｌａ）ｂａｍｂｕｓｉｃｏｌａｉ ｓｐ．ｎｏｖ．。模式标本保存在中山大学生物学系寄生虫学研究室。     

疟原虫与疟疾

结合国内外研究进展,简介了疟原虫的生物学特性,疟疾的发病机理,目前我国疟疾流行概况和防治策略。     

疟疾与疟原虫

疟疾是一种由原虫引起的致命性传染病,在古代因无法确定传染来源,疟疾曾经导致很多人发病甚至死亡。随着生物医学科技的进步,人们发现,疟疾是由疟原虫引起的传染病。疟原虫需要人和雌性按蚊2个宿主才能完成其世代交替的生活史,在人体内,主要包括红外期和红内期及配子体形成过程;在按蚊体内主要包括配子生殖与孢子生殖过程。疟疾的防治需要采取灭蚊、积极治疗患者和预防用药等多种综合措施,为此世界卫生组织和我国都设立了"疟疾日",以宣传和普及疟疾的防治知识。     

《新英格兰医学杂志》：疟原虫首次表现出青蒿素耐药性

造成最致命类型的疟疾的疟原虫正在首次表现出对青蒿素的耐药性,这种药物被誉为根除疟疾的最大希望。关于耐药性的报告——其中一份报告最近发表在《新英格兰医学杂志》（NEJM）上——证实了一种担忧,即提取自一种中药植物中的药物青蒿素正在去其效力。     

《自然》：研究发现恶性疟原虫有效干预途径

抗疟药物通常只对部分种类的疟原虫有效,这是疟疾防治一直以来的难题。英国研究人员日前在破解这一难题方面取得进展。他们发现了一种对所有恶性疟原虫都有效的治疗途径。     

《自然》：研究揭示恶性疟原虫免疫逃逸分子机制

中科院上海巴斯德研究所江陆斌研究组在最新研究中，首次发现恶性疟原虫在人体内实现免疫逃逸的表观遗传分子机制，为研制新型疟疾疫苗提供了实验基础。日前，相关研究成果在线发表于《自然》杂志。     

鼠疟原虫的鉴定

鼠疟原虫(Murine malaria parasites),自1948年首次发现伯氏疟原虫(Plasmodium beghei)以来,相继发现了许多新种(株),且在疟疾寄生虫学、免疫学、遗传学和疟疾化疗等研究中得到广泛应用,已成为现代疟疾实验研究的重要模型之一。我国已从国外引进了伯氏原虫、约氏原虫(Plasmodium yoelii)和少数抗药性系株。随着国际学术交往和实验研究的发展,必将有更多的鼠疟原虫引进。因此熟悉鼠疟原虫生物学特性,掌握其分类鉴定方法,对于疟疾学、寄生虫学以及有关科研教学人员越来越显得必要。     

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.     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.     

Composition and diversity of bird communities in Swedish farmland–forest mosaic landscapes

CapsuleThe amount of forest (at local and landscape scales) and occurrence of residual habitats at the local scale are shown to be the major factors influencing bird community composition in farmland–forest landscapes in central Sweden.

Aims To investigate the importance of local habitat and landscape structure for breeding birds in farmland–forest landscapes in central Sweden.

Methods Breeding birds were censused at 292 points. A detailed habitat mapping was made within 300 m of the points. Within a 300–600 m radius only two major habitats (forests and arable fields) were identified.

Results Cluster analyses of bird communities identified three site types that also differed in habitat composition: (i) partially forested sites in forested landscapes; (ii) heterogeneous sites with residual habitats in mosaic landscapes; and (iii) field-dominated farmland sites in open landscapes. A total of 19 of 25 farmland bird species (restricted to farmland or using both farmland and forest) had the highest abundance in farmland sites with mosaics of forest and farmland, while only six farmland species had the highest abundance in field-dominated sites. The bird community changed from being dominated by farmland species to being dominated by forest species (common in forest landscapes without farmland) at small proportions (10–20%) of forest at the local scale. A major difference in habitat composition between heterogeneous and field-dominated sites was the occurrence of different residual habitats (e.g. shrubby areas and seminatural grasslands). These habitats seemed to influence bird community composition more than land-use, despite covering <10% of the area. Seminatural grasslands were important for bird community composition and species-richness, but grazing seemed to be less important. Among different land-use types, cereal crops were the least preferred fields. Set-asides with tall vegetation and short rotation coppices were positively associated with species-richness of farmland birds.

Conclusion In general, the composition of the landscape was important for bird community composition, although amount and distribution of forests, occurrence of residual habitats and land-use of fields at the local scale had the strongest influence on bird community composition. The possible implications of these patterns for managing farmland–forest landscapes are discussed.     

Chemical constituents from the fruits of Rhus typhina L. and their chemotaxonomic significance

This work describes the isolation and characterization of twenty-nine compounds from the fruits of Rhus typhina L., including eleven flavonoids (1–11), eleven phenols (12–22), two pentacyclic triterpenes (23–24), two organic acids (25–26), one lumichrome (27), one courmarin (28) and one pyrimidine (29) on the basis of their spectroscopic data. Compounds apigenin (1), daidzein (4), orobol (5), 3′, 5, 5′, 7-tetrahydroxyflavanone (6), naringenin (7), butein (8), (-)-catechin (9), quercetin-3-O-α-L-(3″-O-galloyl)-rhamnoside (11), 2-hydroxybenzoic acid (13), 4-hydroxybenzaldehyde (14), vanillin (15), methyl 3,4-dihydroxybenzoate (16), 3,5-dihydroxybenzamide (18), tyrosol (19), caffeic acid (20), 3-(2,4,6-trihydroxyphenyl)-1-(4-hydroxyphenyl)-propan-1-one (21), phlorizin (22), friedelin (23), oleanolic acid (24), 4,4-dimethyl-heptanedioic acid (25), anthranilic acid (26), lumichrome (27), scoparone (28) and uracil (29) have not been recorded before in this plant. This is the first report on the occurrence of compounds 4–7, 9, 11, 13–14, 16, 18–21, 25–29 from the genus Rhus. Moreover, the chemotaxonomic significance of these isolated compounds was also summarized.