构巢曲霉冻干菌粉的制备及优化

【背景】目前,用以降解园林绿化废弃物中木质素的菌剂多为液体菌剂或固体菌剂,鲜有对粉状菌剂的研究。【目的】研制高活性冻干菌粉,提高其冻干存活率并优化其工艺,以解决液体菌剂或固体菌剂在运输、储藏及使用上存在的问题。【方法】以一株木质素降解菌构巢曲霉(Aspergillus nidulans)为研究对象,利用真空冷冻干燥法制备冻干菌粉。以菌株的冻干存活率为评价指标,通过单因素试验筛选适于菌株冻干过程的保护剂种类及浓度梯度,再通过正交试验优化冻干菌粉复合保护剂配方。获得配方后,进一步探究冻干菌粉的复水条件和储藏条件。【结果】保护效果较优的4种保护剂成分经复配后对冻干存活率的影响顺序为蔗糖>葡萄糖>脱脂乳粉> α-乳糖。经优化后的保护剂配方以蔗糖15%、葡萄糖1%、α-乳糖10%、脱脂乳粉1%为最佳;复水条件以生理盐水为溶剂,复水30 min为最优。在此条件下制备和使用冻干菌粉,菌株的冻干存活率可达83.33%,有效活菌数可达1.2×10¹⁰ CFU/g。最佳储藏温度为-20 ℃,在此温度下保存28 d后,菌粉活性无明显下降。【结论】该研究获得的制备和储藏构巢曲霉冻干菌粉条件,具有菌株损失率低、可长时间保存的特点,对推进木质素降解菌在实际生产中应用具有积极作用。     

大豆根瘤菌剂新剂型的研制和应用

应用液体发酵液（５０亿／ｍｌ）研制的根瘤菌液体剂型,其有效活菌数比固体剂型高１．３～２．７倍,在１５～１８℃条件下贮存,６０天后其菌数下降１６％。１９９１～１９９２年,全省２７个试验点试验,液体剂型增产率为１３．４～１６．７％,固体剂型增产率为１３．２～１４．７％,二者增产效果一致,但液体剂型使用量少（５０ｍｌ／亩）,简便易行,特别适于大豆机械播种,同时能降低菌剂的生产成本。     

土壤中质粒pLV1016在快生型大豆根瘤菌间的水平转移

在滤膜、液体培养基和土壤微宇宙 3种系统中 ,研究了接合型质粒 pLV1 0 1 6由快生型大豆根瘤菌 (Rhizobiumfredii)QB1 1 31向R .frediilux3的水平转移及pLV1 0 1 6由QB1 1 31向土著细菌的转移 .接合培养 1d后 ,分别计算供、受体菌的生长速率和质粒转移速率常数 (γ) .结果表明 ,相同接种浓度下 ,滤膜接合时γ值最高 ,土壤中γ值最低 ,γ值不受土壤是否灭菌和是否有大豆植株的影响 ,γ值与初始接种浓度负相关 ,与供、受体的生长速率正相关 .在未灭菌土中检测到 pLV1 0 1 6可转移到土著细菌 ,土著接合子分别属于根瘤菌属和假单胞菌属 .     

安徽省三种产地竹黄菌培养的初步研究

首次对安徽省三种产地的竹黄菌进行了组织分离培养和液体发酵,比较了该菌固体生长状况和液体发酵形成的竹红菌素产量。结果显示,广德卢村的菌种平皿生长速度为0．31cm／d,液体发酵产生的竹红菌素吸光度为0．21;宁国板桥菌种平皿生长速度为0．30cm／d,液体发酵产生的竹红菌素吸光度为0．30;休宁武城的竹黄菌平皿生长速度为1．85cm／d,菌株液体发酵产生的竹红菌素吸光度为O．39。结论表明,休宁武城菌种无论是平皿生长速度还是发酵形成的竹红菌素量都明显优于其它两地的菌株。     

新疆干旱地区根瘤菌资源研究II．根瘤菌抗逆性及生理生化反应特性

从新疆干旱地区获得的根瘤菌对盐,碱、高温和抗菌素等不利条件有较强的抗逆性。测试菌中分别有47％和32％的菌株在0．68mol／L和0．86—1．03mol／L NaCI的YMA培养基上生长;49％菌株在pH4的YMA培养基上生长;85％在pHl0的YMA培养基上生长;43％菌株在43℃条件下生长;55％菌株60℃处理10分钟后仍然能正常生长;41％、26％菌株分别耐500r、1 000r的链霉素。新疆根瘤菌除具备一般根癌菌鉴定特性外,测试菌中50％菌株利用柠檬酸;68％菌株液化明肢;36％菌株水解酪素,与一般根瘤菌反应特性不一致。     

几种外生菌根真菌培养特性的研究

对 4种外生菌根真菌的培养特性进行了研究。结果表明 ,PDMA和PD培养基是培养外生菌根真菌的较适合的培养基 ;木屑、麸皮、米糠、玉米粉、蛭石是培养菌根菌菌剂的较适宜的基质 ;用MMN营养液拌料以及适宜的水分供给都有利于外生菌根真菌的生长。     

嗜热链球菌培养条件的研究

将嗜热链球菌（Ｓｔｒｅｐｔｏｃｏｃｃｕｓｔｈｅｒｍｏｐｈｉｌｕｓ）在６种固体培养基及７种液体培养基中的生长情况进行了比较,结果表明,改良ＩＲＩＥ固体培养基上的溶钙圈大,活菌数最多;在７种液体培养基中亦以改良ＩＲＩＥ的ＯＤ值最高,活菌最多,达８×１０^８／ｍｌ以上。以此培养基做生长曲线,该菌的平衡期为１２～１６ｈ。     

光合细菌最佳生长条件筛选

目的:优化光合细菌的最佳培养条件。方法:通过绘制不同的生长曲线研究不同培养基及不同培养条件等理化因素对2株光合细菌(类球红细菌1.2174、沼泽红假单胞菌1.2180)生长的影响。结果:①1.2174最佳条件:培养基(蒸馏水配制的液体富集培养基和固体ATYP);温度(35℃);pH值(8.0和9.0);接种量(培养基/种子液5:1和4:1)。②1.2180最佳条件:培养基(海水配制的ATYP和蒸馏水配制的液体富集培养基);温度(25℃和35℃);pH值(7.0和8.0);接种量(培养基/种子液2∶1和4∶1)③两株菌的光照、氧需求程度、菌群协同和振荡条件相同。结论:通过筛选,蒸馏水配制的液体富集培养基和固体ATYP培养基、35℃、1000lx、pH值8.0、培养基/种子液4∶1、微氧、有菌群协同、振荡可作为二者的通用培养条件。     

我国亚热带地区豌豆根瘤菌遗传多样性的研究

利用16S rRNA PCR-RFLP,16S rRNA基因序列分析以及16S-23S rRNA IGS PCR-RFLP技术对分离自我国江苏盐城、浙江温州、湖北仙桃及重庆等亚热带地区的42株豌豆根瘤菌（Rhizobium leguminosarum）进行了群体遗传多样性的研究．16S rRNA PCR-RFLP分析以及16S rRNA基因序列分析结果表明：所有供试豌豆根瘤菌可分为两个类群,类群1包括XtP1在内的40株豌豆根瘤菌和尺．leguminosarum USDA2370,为优势种群,占供试菌株的97％;类群2由WzP3和WzP15组成,与Rhizobium etli CFN42相近．16S-23S rRNA IGS PCR-RFLP研究结果表明：所有供试菌株分为18个基因型,在91％的相似性上分为4个类群．其中群Ⅰ与R．leguminosarum USDA2370聚在一起．群Ⅱ仅包括菌株YcP2,YcP3和CqP7等3个菌株．群Ⅲ的菌株分布较广,占供试菌株的优势．群Ⅳ由WzP3和WzP15两个菌株及R．etli CFN42组成．RAPD将供试菌株分为9个群,其中类群Ⅳ仅包括菌株YcP2,群Ⅴ和Ⅸ分别来自温州和仙桃．该结果表明,供试菌株的分类具有明显的地域特征．     

分离自杭子梢等宿主根瘤的30株菌的结瘤特性的研究

对分离自杭子梢、菜豆和决明等宿主根瘤、处于Agrobacterium系统发育分支、DNA-DNA杂交与A.rubi的相似性达到100%的30株土壤杆菌,分属于Agrobacterium、Bradyrhizobium、Mesorhizobium、Rhizobium和Sinorhizobium 5个属的12个参比菌株。nodA PCR的结果表明,30株供试菌中扩增不出nodA,即没有结瘤性。以Sinorhizobium meliloti USDA1002T的nodA做探针对所提取的细菌总DNA进行斑点杂交,在65℃-68℃严谨洗膜条件下,该探针只能与同种的根瘤菌进行杂交,不能与其它属的根瘤菌或土壤杆菌杂交,初步推测共同结瘤基因nodA探针只能对种内根瘤菌的结瘤性进行鉴定。     

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.