共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
【目的】研究微波处理对于分离嗜碱和嗜盐海洋放线菌的效果。【方法】用微波处理7份海泥样品,梯度稀释后涂布于3种分离培养基,分离具有嗜碱和嗜盐特性的海洋放线菌。【结果】微波处理后的7份样品中,4份样品中嗜碱海洋稀有放线菌和3份样品的嗜盐海洋稀有放线菌数量极显著提高;7份样品中的嗜碱、嗜盐海洋小单孢菌属、游动放线菌属、诺卡氏菌属等稀有放线菌数量均有显著增加,不同样品中新分离到链孢菌属、小双孢菌属、链孢囊菌属及其他未鉴定的海洋稀有放线菌,分离到属的数量提高了1-4个。【结论】微波处理不仅显著提高嗜碱和嗜盐海洋放线菌的分离数量,而且明显增加了海洋稀有放线菌的分离种类。 相似文献
3.
4.
5.
6.
7.
8.
超声波处理土样分离放线菌 总被引:6,自引:0,他引:6
【目的】探索超声波处理土壤悬液,增加稀有放线菌的类群。【方法】将西双版纳热带雨林的混合土样,制成土壤悬液,用超声波分别处理0-120s,用平板稀释法分离放线菌,得到纯菌落后测定其16S rRNA基因序列,进行系统发育分析,将分离菌株鉴定到属;用超声波处理已经鉴定到种且常见的10种链霉菌0-5min,后进行培养,测定其存活率。【结果】土壤悬液经超声波处理不同时间,放线菌的数量和种类逐渐增加。超声波处理已知链霉菌1-5min,对链霉菌的数量没有明显影响。【结论】用超声波处理土壤悬液40s,可以大大增加放线菌的出菌总数,明显增加稀有放线菌的种类,是一种经济且简便易行的方法。 相似文献
9.
【目的】为了研究青藏高原北部地区土壤可培养放线菌的多样性,并比较不同选择性分离培养基对高原土壤放线菌的分离效果。【方法】使用9种分离培养基,并尝试添加藤黄微球菌发酵液,对采集自阿里、那曲和海西地区的14份土壤样品中的放线菌进行选择性分离。通过16S r RNA基因序列分析对分离菌株进行初步分类鉴定,并在不同分类水平上统计所分离得到的放线菌多样性。【结果】分离得到去重复后的放线菌255株,分布于放线菌门的8个目,14个科,23个属,包含94个可能的物种。其中至少25个物种可能为新种,分布于13个属。链霉菌属的菌株108株,可能的物种28个,是最主要的优势菌属。分离培养基中添加藤黄微球菌发酵液明显增加了放线菌分离菌株的数量和多样性,稀释的葡萄糖酵母麦芽汁培养基适合分离链霉菌,淀粉甘油脯氨酸培养基、丙酸钠酪蛋白培养基等则适合分离稀有放线菌。【结论】青藏高原北部土壤放线菌多样性非常丰富,并且存在较多的新颖放线菌类群;添加藤黄微球菌发酵液是提高放线菌分离效率的有效手段。 相似文献
10.
《生物技术通报》2018,(9)
为调查塔里木盆地5个代表性生态小区的稀有放线菌分布,并评估它们产生抗生素类活性物质的潜力。采集塔里木盆地5个生态小区混合土样5份,采用7种培养基分离样品中的稀有放线菌。通过检测分析I型PKS、Ⅱ型PKS、NRPS、APH、HMG-CoA五种抗生素合成相关基因的分布,评估该地区稀有放线菌产生抗生素的潜力。结果表明:(1)基于分子鉴定,经合并重复,共分离得到18种稀有放线菌,属于放线菌的10个属。(2)塔里木河河岸林生态小区土样稀有放线菌分离种类最多(10种),为8个属,塔克拉玛干沙漠塔里木河东部生态小区最少(4种),为4个属。(3)18株稀有放线菌中有9株含有I型PKS基因、4株菌含有Ⅱ型PKS基因、4株菌含有APH基因、3株菌含有NRPS基因,有一株链孢囊菌同时含有I型PKS、Ⅱ型PKS、NRPS、APH 4种基因。5个生态小区稀有放线菌种类较多,并含有较为丰富的与抗生素合成相关的基因。 相似文献
11.
12.
13.
14.
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. 相似文献
15.
16.
RICHARD E. NORRIS 《Botanical journal of the Linnean Society. Linnean Society of London》1991,106(1):1-40
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. 相似文献
17.
JOAN VALUÈS MONTSERRAT TORRELL NÚRIA GARCIA JACAS 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(4):399-407
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. 相似文献
18.
肝癌中HBV和HCV基因和抗原的分布及意义 总被引:1,自引:0,他引:1
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 相似文献
19.
20.
H.-R. GREGORIUS 《Biological journal of the Linnean Society. Linnean Society of London》1984,23(2-3):157-165
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. 相似文献
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. 相似文献