北京山区辽东栎林土壤释放CO_2的模拟实验研究

模拟北京山区辽东栎林群落,对该类型土壤释放ＣＯ２过程进行了连续３ａ的实验研究,结果表明：辽东栎林土壤呼吸强度平均为５．９２±１．３２μｍｏｌＣＯ２ｍ－２ｓ－１,在不同月份中,以８月份最高,１０月最低,依次为８月＞７月＞６月＞９月＞１０月（Ｐ＜０．０５）;１３：００为土壤日呼吸的最高峰。温度为影响土壤呼吸的主要因子,二者存在极显著相关关系（ｒ＝０．５６６８,ｐ＜０．００１,ｎ＝９４）。据３ａ观测的土壤呼吸日平均值计算得出,模拟辽东栎林土壤释放ＣＯ２的通量估计范围为１７１．５～２７５．１ｋｇＣＯ２ｈｍ－２ｄ－１,平均为２２３．３ｋｇＣＯ２ｈｍ－２ｄ－１。     

介绍一种高效、简单的DNA沉淀法

毫摩尔级的Ｚｎ２＋可以在适宜条件下导致核酸沉淀物的形成。优化后的ＺｎＣｌ２沉淀法的基本步骤是：５０ｋｂ和２０ｂｐ的ＤＮＡ样品分别置于５０ｍＭＴｒｉｓ（ｐＨ７．０）稀释,ＥＤ－ＴＡ到终浓度小于０．１ｍＭ中,加入０．０１Ｍ磷酸钠缓冲液（ｐＨ７．０）到终浓...     

宝天曼自然保护区栓皮栎林生物量和净生产力研究

对河南内乡宝天曼自然保护区４５年生天然次生栓皮栎林的生物量和净生产力的研究表明,栓皮栎林生物量为１６７．６４１７ｔ·ｈｍ－２,其中乔木层为１５８．８３８２ｔ·ｈｍ－２,占总量的９４．７５％;该林净生产力为８．４８８０ｔ·ｈｍ－２·ａ－１,其中乔木层为７．９２５４ｔ·ｈｍ－２·ａ－１,生物量平均相对生长速率为０．０４１．灌木层的生物量和净生产力分别为０．０６９４和０．０４５６ｔ·ｈｍ－２·ａ－１;而草本层的分别为０．１０４１和０．０９０８ｔ·ｈｍ－２·ａ－１．凋落物现存量为８．６３ｔ·ｈｍ－２,凋落物量为５．０３９５ｔ·ｈｍ－２·ａ－１,分别占总量的５．１５％及５９．３７％．净生产量与叶面积指数、叶量成正比关系,而与叶效率呈负相关关系．     

黑山晋枣芽培养及值株再生研究

以珍稀、优质黑山晋枣液芽为外植体建立了原种无性繁殖系。继代繁殖培养基（ｍｇ／Ｌ）：ＭＳ＋ＢＡ０．１＋ＩＡＡ０．１和ＭＳ＋ＢＡ０．１＋ＩＢＡ０．５,培养３０ｄ平均苗高３．０－３．３ｃｍ,芽繁殖系数３．３－３．５;生根培养基为ＭＳ＋ＩＡＡ０．１＋ＩＢＡ０．２及ＭＳ＋ＩＡＡ０．２＋ＩＢＡ０．２两种,生根率８３．３％,培养４０ｄ平均具根苗高达４．９９ｃｍ,一次成苗,简化程序,缩短成苗期。移载成活率８３．０     

链霉菌Z94-2碱性脂肪酶产生条件及酶学性质

在１５２ 株脂肪酶产生菌中,链霉菌Ｚ９４２ 产脂肪酶活力为５９６ｕ／ ｍＬ,其最适培养基（ｇ／Ｌ） 为：糊精１０ 、黄豆饼粉３０ 、尿素１０ 、Ｋ２ＨＰＯ４ ０－５ 、ＭｇＳＯ４ ０－５ 、ＮａＣｌ １ 和ＡＥＯ９ ０ ．５ ,产酶的最适条件为：初始ｐＨ９ ．５ ～１０－０ ,在２６ ℃培养４８ｈ 。用ＰＶＡ 橄榄油乳化系统测定该酶的最适ｐＨ９ ．８ ,最适温度３７ ℃,在ｐＨ８－６ ～１０－２ 于５ ℃存放２４ ｈ ,酶活力不变。０－１４ｍｏｌ／Ｌ 的氯化钙有较大的激活作用。     

洞庭平原黑线姬鼠繁殖特性研究

１９８６年１０月－１９９０年１０月在湖南省桃源县和汉寿县的稻作区逐月调查,夹捕黑线姬鼠长江亚种２７６８只,雌性占４５。６％。主要繁殖期３－１１月,研究期内的月平均怀孕率为４８．６±４．０％、平均胎仔数为５．３±０．２只。繁殖指数为２．３６±０．２９。以上３个参数及种群性性比有季节性变化,４－５月和７－１０月为２个妊娠高峰;雄性睾丸下位率和雌性怀孕率有同步变动的趋势。５年龄组之间,其性比、怀孕率和繁     

决明组织培养的研究

以草决明无菌苗子叶为外植体,接种于７类诱导愈伤组织的培养基上：Ａ．ＭＳ＋２．０２,４－Ｄｍｇ／Ｌ（以下单位省略）＋０．３ＢＡ＋０．２ＮＡＡ．Ｂ．ＭＳ＋０．２２,４－Ｄ十０．２ＢＡ＋２．０ＮＡＡ．Ｃ．ＭＳ＋１．０２,４－Ｄ＋０．５ＢＡ＋０．２ＫＴ．Ｄ．ＭＳ＋０．７ＢＡ＋１．５ＮＡＡ＋０．１ＫＴ．Ｅ．ＭＳ＋１．５２,４－Ｄ＋０．７ＢＡ十０．２ＭＡＡ．Ｆ．ＭＳ＋０．４２．４－Ｄ＋１．０ＮＡＡ＋０．１ＫＴ．Ｇ．ＭＳＢ（ＭＳ的无机成份和Ｂ５有机成分）＋０．１５ＮＡＡ＋ＢＡ,ＫＴ和ＺＴ各０．５。８～１５天后分别有９０～９９．６％的子叶片被诱导出愈伤组织,并且Ｆ．与Ｃ．类培养基对诱导愈伤组织比较理想,放于Ｇ培养基上的愈伤组织有９．２～３０．２％的芽分化率。芽在生根培养基１／２ＭＳ＋０．２ＩＢＡ中、９８％生根,形成完整的再生植株。     

柱前衍生化HPLC法测定黄芪中黄芪甲苷的含量

目的：建立黄芪中黄芪甲苷的柱前衍化高效液相色谱测定法,并用该法对不同产地黄芪中黄芪甲苷的含量进行比较,方法：以吡啶－苯甲酰氯（２．５：１）为衍生化试剂,对黄芪甲苷分子中的羟基进行苯甲酰化,以甲醇－四氢呋喃－水（９０：４：６,０．２％三乙胺）为流动相,ＶＤ３为内标物,在２３０ｎｍ波长处检测。结果黄芪甲苷在０．００４－０．０８０ｍｇ．ｍＬ＾－１范围内呈线性,相关系数为０．９９９９,平均回收率为９４．７     

液体悬浮振荡培养快速繁殖重瓣大岩桐(简报)

采用重瓣大岩桐幼叶作外植体诱导不定芽的分化,选出 ＭＳ＋ ＢＡ ２． ０ ｍｇ· Ｌ~(－１) ＮＡＡ ０ ２ ｍｇ·Ｌ~(－１)为最佳分化培养基。用此种激素组合进行液体悬浮振荡培养,可提高分化率２．６倍左右。根的诱导以 １／２ＭＳ＋ ＩＢＡ ２．０ ｍｇ~Ｌ(－１)＋ ＡＣ１．０ ｇ·~ Ｌ(－１)为佳。液体悬浮振荡培养中出现的玻璃化现象可采用与固体培养相结合的办法预防与解决。     

香椿离体快繁技术研究

６～７月取香棒当年生半木质化、具腋芽的茎段为外植体,诱导腋芽萌发,进行繁殖培养。通过大量试验,筛选出各阶段适宜的培养基组成。萌芽诱导阶段培养在ＭＳ＋６－ＢＡ０．２ｍｇ／Ｌ中,腋芽萌发早,生长快;在继代和增殖培养中以ＭＳ＋６－ＢＡ０．２ｍｇ／Ｌ效果较好,ＭＳ＋ＺＴ０．２ｍｇ／Ｌ＋ＧＡ３２．０ｍｇ／Ｌ次之。培养３０天繁殖倍数３．１～４．０,在仅含ＭＳ有机元素。铁盐减半、蔗糖１５ｇ／Ｌ的固体培养基中,附     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

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.