双歧杆菌双元蛋白酸奶中特定菌含量及酸度的检测

目的 :检测双歧杆菌双元蛋白酸奶中发酵前后以及在贮藏期间的双歧杆菌和乳酸菌活菌数及酸度的变化。方法 :应用改良MRS琼脂平板法检测含菌量 ,应用吉尔涅尔度表示酸度 (°T)。结果 :双歧杆菌双元蛋白酸奶中双歧杆菌含量为 3 1× 10 7CFU/ml,乳酸菌含量为 4 1× 10 8CFU/ml;°T为 6 5± 5。随着贮藏进程的延长 ,特定菌的含量随贮藏期进程而下降 ,第 4～ 5天下降明显 ;°T随贮藏期延长而逐渐上升 ,保质期内°T为 75～ 110之间。结论 :双歧双元蛋白酸奶符合酸奶国家GB2 74 6～ 1999标准。     

多菌种酸奶中活性乳酸菌的计数方法研究

利用4种选择性培养基MRS、MRS-山梨醇、MRS-5．2、Elliker,采用平板涂布法和倾注接种法。在蜡烛缸法（缺氧）、封口膜法（微氧）和供氧条件下对4种市售多菌种酸奶中保加利亚乳杆菌、嗜热链球菌、嗜酸乳杆菌、双歧杆菌进行选择性计数方法研究。结果表明：蜡烛缸法较能反映乳酸菌活菌数量的实际情况,封口膜法次之;在不同培养条件下4种选择性培养基对于乳酸菌活菌的计数都是灵敏的;而涂布法和倾注法接种活菌数有显著差异,倾注法要优于涂布法。     

不同剂量恩诺沙星对连续培养系统中肠道菌群的影响

目的 研究不同残留剂量恩诺沙星对连续培养系统中肠道菌群数量的影响.方法 建立4套连续培养系统,接种正常人粪便于发酵罐中,连续培养肠道菌群23 d;第23天发酵罐中分别泵入含恩诺沙星剂量为0、1.25、12.5和125 mg/L的培养基,连续加药7 d,第31天停止加药.加药前10 d和加药过程中每隔2 d从4个发酵罐中取样并进行活菌计数.结果 活菌计数结果表明,空白组菌群数量稳定,说明4套连续培养系统运行稳定;低剂量组(1.25 mg/L)恩诺沙星使双歧杆菌下降3个数量级,对其他菌基本无影响;中剂量组(12.5 mg/L)中除拟杆菌外数量均有所下降,厌氧总菌、乳酸菌和肠杆菌停药前数量恢复到加药前水平,需氧总菌、双歧杆菌和肠球菌数量下降后不能恢复原初水平;高剂量组(125 mg/L)中所计数细菌数量均发生变化,需氧总菌、乳酸菌、双歧杆菌、肠球菌和拟杆菌数量下降且停药前不能恢复原初水平,厌氧总菌和肠杆菌数量先降后升,最终计数结果比加药前数量增加.结论 中国现行规定恩诺沙星的日允许摄入量(ADI)可能对人体肠道菌群造成影响.     

酸奶中乳酸菌含量的检测

目的检测酸奶发酵前后以及贮藏期间的乳酸菌活菌数及酸度变化,以对酸奶的质量进行控制.方法应用高层半固体琼脂试管法. 结果酸奶中乳酸菌含量极高,达2.65×1010个/ml以上,并随贮藏时间的延长而发生变化. 糖对酸奶的含菌量无明显影响.双菌酸奶比单菌酸奶含菌量高,常可达到倍增,pH值随发酵和贮藏进程而下降.结论高层半固体琼脂试管法操作简便、快速、准确、活菌检出率高.     

菊花水煎液对长双歧杆菌促生长作用的探讨

目的研究菊花水煎液促进长双歧杆菌的体外增殖与活性的作用,初步探讨它作为一种双歧因子的条件。方法以菌液A600值、pH、活菌计数及发酵牛乳的凝乳时间、pH、滴定酸度等为指标,研究菊花水煎液对长双歧杆菌生长的影响,并用K—B琼脂法初步研究菊花水煎液对几种常见肠道菌群的抑／促菌作用。结果在5％添加菊花水煎液的培养基中长双歧杆菌的菌体浓度（A600值及活菌计数）均明显高于空白对照,菌液pH也均低于空白对照;长双歧杆菌发酵含有菊花水煎液的牛奶后,凝乳时间缩短,乳液的滴定酸度高于空白对照,pH也相应降低。菊花水煎液对几种常见肠道致病菌有较强的抑菌作用。结论菊花水煎液能促进长双歧杆菌的体外增殖与活性,且具有一定的选择性;菊花有可能成为一种良好的双歧因子或益生元制剂的候选物质。     

乳酸菌遗传育种研究现状

乳酸菌是一大类发酵糖产生大量乳酸的细菌的通称 ,主要包括乳杆菌、双歧杆菌、乳球菌、链球菌、肠球菌、明串珠菌、片球菌、芽胞杆菌等属。乳酸菌在医药、工业、农业等与人类生活密切相关的重要领域有很高的应用价值 ,如乳杆菌、双歧杆菌、嗜热链球菌发酵的酸奶 ,应用于保健食品 ;植物乳杆菌应用于青贮饲料 ;乳杆菌、双歧杆菌等应用于临床医疗。但目前很多菌种都是野生型的 ,其某些性状、功能不太令人满意。因此 ,许多研究者通过微生物遗传育种来改良野生型菌株的某些遗传性状 ,以更适合开发利用其价值。1　传统的乳酸菌菌种改良方法1 1　…     

植物乳杆菌ST-Ⅲ发酵特性的研究

在添加5%(v/v)番茄汁的改良配方乳中对植物乳杆菌ST-Ⅲ单菌或与嗜热链球菌及保加利亚乳杆菌混合发酵的生长特性、发酵乳风味进行了研究.结果表明,在脱脂乳中添加5%(v/v)番茄汁可以明显缩短植物乳杆菌ST-Ⅲ单菌发酵时的凝乳时间,提高其活菌数.在改良的配方乳中,三菌混合发酵制备的发酵乳具有良好的酸奶风味、无涩味.但与...     

单方中药马蹄香和5种微生态制剂中的低聚糖含量测定和比较分析

目的 深入认识马蹄香治疗病毒肠炎的有效成分.方法 应用戴安CS-3000离子色谱分析仪测定马蹄香散剂和酪酸梭菌二联活菌散剂、双歧杆菌乳杆菌三联活菌片、双歧三联活菌胶囊、布拉酵母菌散剂及乳酸菌素片5种微生态制剂中的10种低聚糖含量.结果 低聚糖总含量:双歧三联活菌片＞酪酸梭菌二联活菌散剂＞双歧三联活菌胶囊＞布拉酵母菌散剂＞乳酸菌素片＞马蹄香散剂.在单个的低聚糖含量中,半乳糖三糖含量:酪酸梭菌二联活菌散剂＞双歧三联活菌片＞马蹄香散剂＞乳酸菌素片＞布拉酵母菌散剂＞双歧三联活菌胶囊;棉籽糖含量:双歧三联活菌片＞双歧三联活菌胶囊＞布拉酵母菌散剂＞乳酸菌素片＞酪酸梭菌二联活菌散剂＞马蹄香散剂;水苏糖含量:双歧三联活菌胶囊＞布拉酵母菌散剂＞乳酸菌素片＞酪酸梭菌二联活菌散剂＞马蹄香散剂＞双歧三联活菌片;毛蕊花糖含量:马蹄香散剂＞乳酸菌素片＞双歧三联活菌胶囊＞双歧三联活菌片＞酪酸梭菌二联活菌散剂＞布拉酵母菌散剂;潘糖含量:马蹄香散剂＞布拉酵母菌散剂＞酪酸梭菌二联活菌散剂＞其他;鼠李糖含量:乳酸菌素片＞布拉酵母菌散剂＞马蹄香散剂＞其他;麦芽四～七糖含量:乳酸菌素片＞马蹄香散剂＞布拉酵母菌散剂＞其他.结论 微生态制剂中低聚糖主要是半乳糖三糖、棉籽糖和水苏糖的含量高.与其他微生态制剂比较,马蹄香散剂中毛蕊花糖和潘糖的含量最高,半乳糖三糖、鼠李糖和麦芽四至七糖的含量也较高,这些低聚糖的含量高可能与改善肠道菌群和治疗病毒性肠炎的有效性有关.     

保健食品双歧杆菌和乳酸菌计数方法的优化

目的通过稀释液和培养基的选择对保健食品双歧杆菌和乳酸菌计数方法进行优化。方法对2个品种6个批次的益生菌类保健食品,分别采用2种稀释液和3种培养基进行双歧杆菌和乳酸菌计数,并比较结果。结果选择CYS缓冲液为最优稀释液,M-TOS培养基为双歧杆菌计数的最优培养基,BBL培养基为乳酸菌总数计数的最优培养基。结论优化方法所得菌数均明显优于国标方法,可以用于保健食品的双歧杆菌和乳酸菌计数。     

分离自婴儿粪便的嗜酸乳杆菌和长双歧杆菌的常温保存探究

目的:试验不同的保护剂成分配方,探究分离自婴儿粪便的2种益生菌(嗜酸乳杆菌和长双歧杆菌)在常温条件下保持较高活性的可行方法。方法:利用均匀设计实验方法设计保护剂配方,用于保存特定高活性高稳定性的菌种,在不同时间点检测活菌数,分析数据得出最佳保护剂成分比例。结果:嗜酸乳杆菌10A31保护剂最佳配方为:海藻糖∶谷氨酸∶天冬氨酸=5∶24∶24;长双歧杆菌11A11保护剂最佳配方为:海藻糖∶谷氨酸∶麦芽糖=34∶11∶10;用最佳保护剂配方保存后,嗜酸乳杆菌10A31在200 d时的菌落计数结果为3.87×109CFU/g,长双歧杆菌11A11在160 d时为1.53×109CFU/g,均具有较高的活性。结论:最佳保护剂配方使2个菌种常温保存期至160 d。     

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.