对虾的不同发育阶段对有机磷农药的敏感性及其机理初探

对硫磷、甲基异柳磷和久效磷对中国对虾无节幼虫、蚤状幼虫、糠虾幼虫、仔虾的２４ｈＬＣ５０分别为６．０、４．０、３．８、１８×１０－３ｍｇ·Ｌ－１;８．０、３．５、３．５、３０×１０－３ｍｇ·Ｌ－１;２４、２４、２４、０．９ｍｇ·Ｌ－１;敌敌畏均为４８×１０－３ｍｇ·Ｌ－１;对硫磷对南美白对虾为８．６、８．２、８．０、２．０×１０－３ｍｇ·Ｌ－１．研究结果表明,对虾的幼虫前期对硫代磷酸酯类农药的抗性强,仔虾及以后各期抗性弱,而各幼虫期对磷酸酯类农药的敏感性基本相同．     

芋的组织培养

１植物名称芋（Ｃｏｌｏｃａｓｉａｅｓｃｕｌｅｎｔａ）品种江汉芋（多子芋类型）。２材料类别茎尖及微芽。３培养条件分化培养基：（１）ＭＳ＋６－ＢＡ３．０～５．０ｍｇ·Ｌ－１（单位下同）＋ＮＡＡ０．５;（２）ＭＳ＋６．ＢＡ１．０～２．０＋ＮＡＡ０．５。诱导生根培养基：（３）ＭＳ＋６－ＢＡ１．０～２．０＋ＮＡＡ０．１。培养基（１）、（２）中另加蔗糖３０ｇ·Ｌ－１,培养基（３）中加蔗糖１０ｇ·Ｌ１,琼脂６～７ｇ·Ｌ－１,ｐＨ５．８～６．０,１２１℃高温高压灭菌１５ｍｉｎ左右。光照度１５５～２０００ｌｘ,光…     

矮生鸡冠花的离体快繁及试管苗开花

１植物名称矮生鸡冠花（Ｃｅｌｏｓｉａｃｒｉｓｔａｔａ）。２材料名称无菌种子苗顶芽、腋芽。３培养条件基本培养基为ＭＳ。培养基组合为：（１）ＭＳ＋ＢＡ１－２ｍｇ·Ｌ~（－１）（单位下同）＋ＮＡＡ０．１～０．２;（２）ＭＳ＋ＢＡ２＋ＩＡＡ０．２;（３）ＭＳ＋ＫＴ２;（４）ＭＳ＋ＢＡ０．１～０．５。以上培养基均含３％蔗糖,０．６％琼脂,ｐＨ为５．８,培养温室为（２６±２）℃,光照１２ｈ．ｄ~（－１）（２０００ｌｘ）。４生长与分化情况４．１无菌材料的获得成熟的种子置７０％酒精中摇动５０ｓ后,转入饱和漂白粉溶…     

全缘金粟兰的组织培养和繁殖

１植物名称全缘金粟兰（Ｃｈｌｏｒａｎｔｈｕｓｈｏｌｏｓｔｅｇｉｕｓ）。２材料类别顶芽、带节的茎段。３培养条件（１）芽繁殖培养基：ＭＳ＋６－ＢＡ２．０～３．０ｍｇ·Ｌ－１（单位下同）＋ＩＢＡ０．２～０．３;（２）生根培养基：ＭＳ＋ＩＢＡ０．５。培养基中添加３％蔗糖,０．８％琼脂,ｐＨ５．８。培养温度为２５～２８℃,光照１２ｈ·ｄ－１,光照度约为１５００ｌｘ。４生长与分化情况４．１无菌材料的获得以芽尖和带腋芽的茎段为外植体,经消毒后,在超净工作台上,除掉部分叶片,将其接种于芽繁殖培养基上,经６０ｄ左…     

紫菀花序芽培养及植株再生

１植物名称紫菀（Ａｓｔｅｒｔａｔａｒｉｃｕｓ）。２材料类别花序芽。３培养条件愈伤组织、不定芽诱导及增殖培养基：（１）ＭＳ＋６－ＢＡ０．５～２．０ｍｇ·Ｌ－１（单位下同）;生根培养基：（２）ＭＳ＋ＮＡＡ０．５～２．０＋６－ＢＡ０．２,（３）１／２ＭＳ（大量元素减半）＋ＮＡＡ０．５～２．０＋６－ＢＡ０．２。上述培养基均加０．８％琼脂和３％蔗糖,高温高压灭菌前ｐＨ值调至５．８。培养温度为（２３１２）℃,每天光照１２ｈ,光照度为１５００～２０００ｌｘ４生长与分化情况４．１愈伤组织及不定芽的诱导剪取长约０…     

长寿花叶片愈伤组织的诱导和植株再生

１植物名称长寿花（Ｋａｌａｎｃｈｏｅｂｌｏｓｓｆｅｌ－ｄｉａｎａ）。２材料类别叶片。３培养条件培养基：（１）ＭＳ＋２,４－Ｄ１ｍｇ·Ｌ~（－１）（单位下同）＋６－ＢＡ０．１;（２）ＭＳ＋ＮＡＡ１＋６．ＢＡ０．１;（３）ＭＳ＋６－ＢＡ１＋ＮＡＡ０．１;（４）１／２ＭＳ。以上培养基均加蔗糖３０ｇ·Ｌ~（－１）,琼脂８ｇ·Ｌ~（－１）,ｐＨ值为５．８,高压灭菌,培养温度２３～２６℃,光照１２ｈ·ｄ~（－１）,光照度１０００ｌｘ左右。４生长与分化情况４．１无菌材料的获得从实生苗上取下叶片,经自来水冲洗后,用…     

无花果曲霉原生质体形成与再生条件的探讨

根据正交试验得出无花果曲霉原生质体形成的最佳条件,用１％的混合酶液（０．５％纤维素酶＋０．２５％蜗牛酶＋０．２５％溶菌酶）作用无花果曲霉菌体细胞,原生质体产量达３．２×１０７个·ｍｌ－１,渗透压稳定剂为０．６ｍｏｌ·Ｌ－１ＫＣｌ于０．２ｍｏｌ·Ｌ－１ＰＯ３＋４（ｐＨ５．８）中,酶解时间和酶解温度分别为３．０ｈ、３０℃．比较不同酶解时间、再生稳定剂和碳源等因素对原生质体再生的影响,可确定最佳再生条件,再生率达３０％以上．     

EDTA对Cu在水生微宇宙中的毒性和分布的影响

利用实验室人工合成培养微宇宙,研究不同浓度ＥＤＴＡ（０．０、１．０、８．０ｍｇ·Ｌ－１）对微宇宙中Ｃｕ（２．０ｍｇ·Ｌ－１）的毒性及Ｃｕ的分布．结果表明,在微宇宙运行过程中,投加２．０ｍｇ·Ｌ－１Ｃｕ后,ＥＤＴＡ浓度为０．０ｍｇ·Ｌ－１试验组中大型种群大小、叶绿素ａ浓度及总初级生产力与总呼吸的比值（Ｐ／Ｒ）随时间变动曲线,明显低于其它试验组的曲线,ＥＤＴＡ的存在削弱了Ｃｕ对大型和藻类的毒性作用,并缓解了Ｃｕ对生态系统代谢功能的干扰;同时改变了微宇宙中Ｃｕ在不同隔室中的分布,水体中Ｃｕ相对增加（０．１％～６．７％）,沉积物中相对减少（０．８％～６．５％）;ＥＤＴＡ的存在影响了藻类和大型对Ｃｕ的积累系数（ｐ＜０．０５）．     

芥蓝的组织培养和快速繁殖

１植物名称芥蓝（Ｂｒａｓｓｉｃａａｌｂｏｇｌａｂｒａ）优良种株,取自广东汕头白沙蔬菜原种研究所。２材料类别未开花的植株基部腋芽。３培养条件（１）诱导丛生芽培养基为Ｍ１：ＭＳ＋６－ＢＡ２ｍｇ·Ｌ‘（单位下同）＋ＮＡＡ０．２;Ｍ２：ＭＳ＋６－ＢＡ１＋ＮＡＡ０．１;Ｍ３：ＭＳ＋６．ＢＡ１＋ＮＡＡ０．２。上述培养基均含蔗糖３％,琼脂０．８％,ｐＨ５．８～６．０。（２）生根培养基：ＭＳ＋ＮＡＡ０．５＋２％蔗糖＋０．４５％卡拉胶（０．７％琼脂）。培养温度２０～２５℃,光照１２ｈ．ｄ－１,光照度２０００１ｘ４…     

紫羊蹄甲的组织培养和快速繁殖

１植物名称紫羊蹄甲（Ｂａｕｈｉｎｉａｐｕｒｐｕｒｅａ）。２材料类别带腋芽的茎段。３培养条件（１）启动培养基：ＭＳ＋６－ＢＡ２．０ｍｇ·Ｌ－１（单位下同）＋ＮＡＡ０．０１;（２）诱导分化培养基：ＭＳ＋６－ＢＡ１．０～２．０＋ＩＢＡ０～０．１;（３）生根培养基：１／２ＭＳ＋ＩＢＡ０．５～１．０。上述培养基均入蔗糖３０ｇ·Ｌ－１,琼脂０．５％,ｐＨ值５．８。培养温度２５℃,光照度２５００～３０００ｌｘ,每天光照１２ｈ。４生长与分化情况４．１启动培养材料取自南京中山植物园温室种植的三年生母树。将带腋芽的…     

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.