应用肠杆菌科四个属的诊断噬菌体快速诊断沙门氏菌

本文报告应用弗氏柠檬酸细萄噬菌体3组,大肠埃希氏菌噬菌体4组,阴沟肠杆菌噬菌体1组和沙门氏菌O-I噬菌体快速诊断沙门氏菌的结果。沙门氏菌0-I噬菌体可裂解沙门氏菌属地方株1393株中的1351株(97％)。柠檬酸细菌属噬菌体和共可裂解柠橡酸细菌属地方株381株中的362株(95％)。阴沟肠杆菌噬菌体Ent可裂解阴淘肠杆菌地方株l 50株中的133株(84．2％)。埃希氏菌属噬菌体E—1、E一2、E-3和E-4共可裂解埃希氏菌属地方株683株中的567株(83％)。由于E一1和E一2噬菌体的联合使用,可使o I噬菌体对埃希氏菌属地方株的误诊率从6．3％下降到0．6％。E一4噬菌体对沙门氏菌属地方株的误诊率可因与。一I噬菌体的联合使用而从0．36％下降到0．07％。     

解脂假丝酵母(Candida lipolytica)B74利用正烷烃产生柠檬酸的研究

解脂假丝酵母(Candida lipolytica)B14以正烷烃为碳源可以形成柠檬酸和异柠檬酸。在正烷烃、(NH4)2SO4 过磷酸钙、玉米浆和NaCl等组成的培养基上,发酵4天,发酵液中柠檬酸含量达6．95％。用吡啶显色,总酸(以柠檬酸计)含量达13.78％。将异柠檬酸转化为柠檬酸,发酵液中柠檬酸含量上升到12—13％,柠檬酸占总酸的比例从40一50％提高到80—90％。原料转化率(产酸量与正烷烃量之比)按柠檬酸计达1I 2％,总醛转化率达132．5％,最高达184．1％。     

高浓度薯干直接发酵柠檬酸的研究——黑曲霉5016的选育

本文报道了利用高浓度薯干粉产生柠檬酸的菌种选育。从一份土壤样品中,分离出一株黑曲霉野生菌株628。628菌株能代谢柠檬酸。在发酵培养基中,菌丝呈纤维状。利用“钻r-射线处理628菌株,并采用选择培养的筛选方法,获得了一支突变株黑曲霉5016(Aspergillusniger 5016)。在发酵培养基中5016菌株的菌丝形成粗糙的小球生长。在33℃振荡培养5天,其柠檬酸可达15—17％,对总糖的转化率为90％,而目不含其他的有机酸。     

解脂假丝酵母8-2利用液体石蜡发酵生产工业用柠檬酸

果园土壤筛选出一株能利用液体石蜡生成柠檬酸的酵母菌,经鉴定为解脂假丝酵母(Candida lipolytica) 8—2。在该菌所产生总酸中约50％为柠檬酸。摇瓶及500升发酵罐试验证明,8—2菌在含10—12％液体石蜡、0.25—0.5％玉米浆及6％CaCO,作中和剂的培养基中,一般能生成7％以上的柠檬酸,最高可达10．72％。此种工艺可生产工业用柠檬酸。     

苹果渣基质柠檬酸高产菌株选育

分别以固态苹果渣、苹果渣固态酶解物、苹果渣酶解液和10%葡萄糖溶液为发酵基质研究了17株野生黑曲霉的柠檬酸产生能力,并对获得的4株柠檬酸高产菌进行了诱变育种。结果表明:17株黑曲霉在4种发酵基质中均能良好生长并发酵产生柠檬酸,不同菌株在同一发酵基质中产酸能力间存在差异。FG17、FG23、FG26、FG30等4株菌苹果渣基质柠檬酸产生能力较高,且在4种不同发酵基质中产酸性能稳定。4株菌分别经紫外线和60Co-γ射线诱变后得到的正向突变株柠檬酸产率均显著提高,突变株中FG26-15-4(UV)发酵苹果渣后柠檬酸产率最高,达11.32%,FG23-13-3(γ)发酵苹果渣酶解液后柠檬酸产率最高,达2.73 mg/mL,均高于现有研究报道,可作为不同类型苹果渣基质柠檬酸发酵用菌种。     

食品上的应用

900831 碳源的类型和浓度对黑曲霉生产柠檬酸的影响研究了碳源及其浓度对黑曲霉(Aspergillus niger)B60生产柠檬酸的影响。麦芽糖、蔗塘、葡萄糖、甘露糖和果糖给予高的柠檬酸产率。在糖浓度为10％时(葡萄糖例外,为6.5％)产率最高。糖浓低于2.5％时不产生柠檬酸,用1％蔗     

甘薯原料发酵柠檬酸的菌种选育及发酵条件的研究

从腐烂水果上分离池一株柠檬酸产生菌——黑曲毒,经两次不同能源的γ-射线照射获得一株变异株,产酸能力比原菌株提高50％以上,编号为γ-144。Aspergillus niger γ-144能够利用甘薯粉做为唯一营养源进行柠檬酸发酵,在12％甘薯粉培养基上振荡培养5天,总酸产量达到9％,对总糖转化率达90％。     

食品上的应用

942055黑曲霉抗2一脱氧葡萄糖突变株在半固态培养中由纤维=糖生产柠檬酸[英]/Sarangbin,S.…∥Appl.Mierobi01.Bioteehn01.一1993,40(2～3).一206~210["译自DBA,1994,'13(4),94—02141] 研究了用甘蔗渣作为支持物进行黑曲霉半固态发酵由纤维=糖生产柠檬酸。用含葡萄糖作为碳源的基本培养基,由亲株Yang nO.2诱导产生抗2一脱氧葡萄糖(DG)的突变株。筛选出代表性突变株M155,并进一步进行突变,在含纤维二糖作为碳源的基本培养基上获得了新系列的抗DG突变株。用于柠檬酸生产的合成培养基(SS)每升含2 gNHtNO 3、10gKH2PO‘、250rag MgS…     

降解山楂汁中柠檬酸酵母菌的筛选及其降酸特性研究

采用酸碱滴定法和高效液相色谱法对山楂汁中主要有机酸进行分析,结果表明柠檬酸占总酸的83.5%;分别以柠檬酸和山楂黄酮为唯一碳源,筛选能降解柠檬酸而不利用山楂黄酮的酵母菌,结果获得6株菌;再以山楂汁为培养基进行复筛,得到一株酵母菌,该菌能有效降解山楂汁中柠檬酸而对山楂黄酮的影响较小;经鉴定这株菌属于毕赤酵母属,定名为Pichia sp.Y1。发酵特性研究表明该菌在山楂汁中20℃培养3d,总酸量从19.60g/L下降到352g/L,而对黄酮含量无显著影响。     

柠檬酸发酵高温生产菌株选育

以黑曲霉(Aspergillus niger)H-142为出发菌株,通过r-射线、硫酸二乙酯及高温热处理单独或复合诱变,并采用高温、高酸及高渗培养条件定向筛选,从600多株突变株中筛选出一支耐高温柠檬酸高产菌株HQL-601。其发酵温度为40-41℃,周期60—64小时,20％山芋粉摇瓶产酸13％。发酵液的高压液相色谱分析结果表明,其产酸组成明显优于现生产菌株。     

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.