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1.
Detecting cellulase and esterase enzyme activities encoded by novel genes present in environmental DNA libraries 总被引:3,自引:0,他引:3
Rees HC Grant S Jones B Grant WD Heaphy S 《Extremophiles : life under extreme conditions》2003,7(5):415-421
A genomic DNA library was made from the alkaliphilic cellulase-producing Bacillus agaradhaerans in order to prove our technologies for gene isolation prior to using them with samples of DNA isolated directly from environmental samples. Clones expressing a cellulase activity were identified and sequenced. A new cellulase gene was identified. Genomic DNA libraries were then made from DNA isolated directly from the Kenyan soda lakes, Lake Elmenteita and Crater Lake. Crater Lake clones expressing a cellulase activity and Lake Elmenteita clones expressing a lipase/esterase activity were identified and sequenced. These were encoded by novel genes as judged by DNA sequence comparisons. Genomic DNA libraries were also made from laboratory enrichment cultures of Lake Nakuru and Lake Elmenteita samples. Selective enrichment cultures were grown in the presence of carboxymethylcellulose (CMC) and olive oil. A number of new cellulase and lipase/esterase genes were discovered in these libraries. Cellulase-positive clones from Lake Nakuru were isolated at a frequency of 1 in 15,000 from a library made from a CMC enrichment as compared to 1 in 60,000 from a minimal medium enrichment. Esterase/lipase-positive clones from Lake Elmenteita were isolated with a frequency of 1 in 30,000 from a library made from an olive-oil enrichment as compared to 1 in 100,000 from an environmental library.Communicated by K. Horikoshi 相似文献
2.
Isolates of Pseudomonas syringae pv. tabaci, including 21 strains of the wildfire pathogen and 2 strains of the angular leafspot pathogen, were isolated from 143 rhizosphere and soil samples collected from 11 tobacco fields in Wisconsin. These pathogens were isolated by inoculating rhizosphere and soil washings into tobacco leaves and isolating the bacteria from wildfire or angular leafspot lesions that developed on the leaves. The wildfire isolates were from the rhizospheres of tobacco and Panicum capillare and from soil. While the majority of these were from wildfire-diseased fields, one isolate was from a field without disease symptoms; both angular leafspot isolates were from fields without angular leafspot symptoms. The majority of wildfire isolates were race 1, but three were race 0, and one was a new race. In three fields multiple races of wildfire were found. Both angular leafspot isolates were race 1. Two wildfire and one angular leafspot isolates were from fields where the cultivars were resistant to the races isolated. 相似文献
3.
Data from cranial specimens of adult E. jubatus were analyzed to compare intraspecific morphology of skulls. Males and females were grouped separately to avoid bias from sexual dimorphism. Geographic variation was observed in adult male E. jubutus , indicating the potential presence of three morphologically disparate groups: those from Alaska, those from California, and those from Japan and Russia. Although sample sizes were small, results from cluster and discriminant function analyses indicated that specimens from eastern and western Alaska were morphologically similar, and that the most divergent specimens for the species appeared to be those from Japan. Skulls from Alaska possessed a typically longer, less robust skull, whereas those from Japan appeared smaller, yet most robust. Skulls from California were intermediate. 相似文献
4.
Fusarium species were isolated from plant debris in soil samples collected from cultivated maize fields and from undisturbed
grasslands in two areas of the Transkei region. A total of 1205 Fusarium isolates were recovered from 27 soil samples. Fifteen
Fusarium species were recovered from plant debris from Bizana soils and 13 Fusarium species from plant debris from Centane
soils. The two dominant Fusarium species in both areas were F. oxysporum and F. equiseti. Very few isolates of F. moniliforme
and F. subglutinans were recovered, but both of these species had significantly higher relative densities in cultivated soils
than in undisturbed soils.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
5.
目的调查浙江中医药大学附属第一医院重症监护病房(ICU)临床分离株的病原分布及细菌耐药状况,并与非ICU相比较,观察二者的区别,为临床用药提供有效的参考价值。方法收集该院2010年1月至2011年6月临床送检的各类标本,采用VITEK-2 compact全自动微生物鉴定仪,用GPI、GNI、ANC、YST鉴定卡、AST—GN13、AST—GP67药敏卡进行菌株的鉴定和药敏,根据美国临床实验室标准化协会(CLSI2010)制定的指导原则,判断细菌的耐药率。结果共计分离到2341株细菌,其中ICU有505株占21.6%,非ICU有1836株占78.4%。在ICU分离到的细菌中,革兰阳性菌占23.2%(117/505);非发酵菌占47.3%(239/505)。在非ICU中,革兰阳性菌占34.4%(632/1836);非发酵菌20.2%(371/1836)。ICU前3位细菌分别为鲍曼不动杆菌、肺炎克雷伯杆菌、洋葱伯克霍尔德菌。非ICU前3位依次为大肠埃希菌、金黄色葡萄球菌、铜绿假单胞菌。非发酵菌中,铜绿假单胞菌和鲍曼不动杆菌对哌拉西林/他唑巴坦、头孢他啶、头孢吡肟、亚胺培南、美洛培南的耐药率,ICU和非ICU差异有统计学意义(P〈0.05)。亚胺培南对ICU铜绿假单胞中的MIC50是非ICU的8倍,MIC。值相当。ICU与非ICU分离的葡萄球菌属细菌对头孢唑啉、环丙沙星、左旋氧氟沙星的耐药率差异有统计学意义(P〈0.05)。ICU和非ICU葡萄球菌对利奈唑胺、万古霉素、替考拉宁全部敏感。结论ICU患者分离的细菌以革兰阴性菌为主,其中又以非发酵菌占大多数。非ICU患者分离的革兰阳性菌比例明显要比ICU高。在主要的致病菌中,ICU的耐药率明显高于非ICU。 相似文献
6.
Cynthia M. Perry 《Environmental Biology of Fishes》1990,27(2):153-155
Synopsis Measurements were made on Atlantic salmon from five sources in New England. Fish were reared at pH 7.0 and 5.2 from hatch to 199, 270 or 440 days. Length and weight were smaller in Atlantic salmon, Salmo salar, that were continuously exposed to low pH in the laboratory. Length and weight in neutral pH water varied among fish from the different sources. Fish from the Green Lake, Craig Brook, and Tunison sources were not significantly different in their lengths over time. Cortland and landlocked Atlantic salmon were not significantly different from one another but were significantly different from the other three sources. At pH 5.2, there were no significant differences in length between fish from any of the five sources. The Cortland salmon were significantly different from the other four sources in respect to their weight over time at neutral pH. At pH 5.2, there were no significant differences between any of the five sources.Cooperators are the U.S. Fish and Wildlife Service, the Maine Department of Inland Fisheries and Wildlife, the University of Maine, and the Wildlife Management Institute 相似文献
7.
旱生和湿生生境对蒲公英体内抗氧化物质的影响 总被引:5,自引:0,他引:5
选择旱生和湿生生境中生长的蒲公英(Taraxacum mongolicum Hand.-Mazz)分根、叶、花序分别测定抗氧化成分及总抗氧化能力,并比较了SOD同工酶谱的变化情况。结果表明不同生境选取的蒲公英叶片中抗氧化物质以SOD、POD、CAT等抗氧化酶和Vc等小分子为主,花序中可溶性糖、类黄酮和绿原酸含量最高;湿生蒲公英各器官尤其是根中的SOD、CAT、POD活性高于旱生蒲公英对应器官中的酶活性,旱生蒲公英各器官尤其是花序中的可溶性糖、类黄酮和绿原酸含量高于湿生蒲公英对应器官中的含量;旱生和湿生生境未诱导出新的SOD同工酶带;旱生和湿生蒲公英对应器官的总抗氧化能力接近。 相似文献
8.
萜类是海洋天然产物中最多的化合物,相当多的海洋萜类中含有卤素,这些卤代萜类大多是结构新颖、生理功能独特的生物活性物质。本文从国内外关于海洋萜类文献上搜集了有关海洋含卤萜类物质75种,并从其来源、结构类型及生物活性几方面进行了综述。这些化合物主要来源于海藻、海兔、海绵以及软珊瑚等海洋生物体。结构类型主要是倍半萜、二萜、单萜,三萜很少。大多含卤萜类具有细胞毒性,抗病毒、抗肿瘤及抗癌活性。 相似文献
9.
Riitta Aho 《Mycopathologia》1983,83(2):65-73
Hair samples from domestic and laboratory animals with suspected dermatophytosis were examined for the presence of saprophytic fungi. A nutritionally poor base medium, developed by the author, was used in the isolation and identification of the saprophytes. Three hundred and ninety-four specimens were examined of which 246 were from dogs, 75 from cats, 30 from horses, 19 from cows, 12 from guinea pigs, 5 from rats, 2 from parakeets, 2 from chinchillas and one each from a goat, a mink and a lesser panda (Ailurus fulgens). Moulds classified in 32 genera were isolated. The commonest in order of frequency were members of the genera Penicillium, Cladosporium, Aspergillus, Mucor, Aureobasidium, Alternaria, Scopulariopsis, Trichoderma and Trichothecium. The yeasts that were isolated were not identified. Aureobasidium pullulans was isolated significantly more often (chi 2 test p less than 0.025) from the dog samples than those from cats, Cladosporium spp. in the samples from dogs than horses, Mucor spp. from the cow samples than horses, Penicillium spp. from the dog samples than those of cats or horses. Skin infections caused by any of the contaminants were not encountered. 相似文献
10.
在室内条件下通过将红火蚁Solenopsis invicta Buren异巢不同品级的个体置于同一容器中,对红火蚁的巢间相容性进行研究。结果表明,蚁后与异巢幼蚁共处时,异巢幼蚁的羽化率为33.3%,与对照处理的38.3%(蚁后与同巢幼蚁共处)无显著差异。工蚁与异巢幼蚁共处时,异巢幼蚁的羽化率为53.7%,与对照处理的72.2%(工蚁与同巢幼蚁共处)无显著差异。蚁后与异巢工蚁共处时,异巢蚁后的存活率为45%,与对照处理的61.7%(工蚁与同巢蚁后共处)无显著差异。有翅繁殖雌蚁与异巢工蚁共处时,异巢工蚁的存活率为86.7%与对照处理的99.4%(工蚁与同巢有翅繁殖雌蚁共处)存在显著差异;异巢有翅雌蚁的存活率为22.2%,与对照处理的88.9%(工蚁与同巢有翅繁殖雌蚁共处)存在显著差异。由此可见,同区域内红火蚁异巢各品级间存在一定程度的相容性,并巢行为有可能发生。 相似文献
11.
利用从126个RAPD(RandomAmplifiedPolymorphicDNAs)随机引物中筛选到的可扩增出清晰条带、主带明显、稳定的8条引物,对采集自江苏、安徽和江西不同寄主的45个Phytophthoraboehmeriae菌株进行全基因组DNARAPD标记遗传多样性分析。选用引物共标出DNA指纹图带68条,其中多态性条带20条,多态性检测率为29.4%,表明该种内不同地区和寄主来源的菌株间变异较小。利用Popgene软件计算供试菌株间的遗传距离并绘制聚类树状图,供试菌株被划分为2个遗传聚类组。菌株间的遗传相似性与菌株的寄主来源有一定的相关性,来自江苏、江西和安徽棉花上的27个菌株被划分在同一遗传聚类组内,而分离自构树、枫杨和苎麻的18个菌株被划分在另一个遗传聚类组。结果还表明菌株间遗传相似性与其地区来源无直接相关性。 相似文献
12.
用金桔茎段为外植体,培养在附加1.0毫克/升BA和0.l毫克/升IBA的MS培养基上,诱导愈伤组织和芽形成。观察了愈伤组织和芽形成过程中的组织细胞学变化。培养一周后,在茎组织切口两端开始膨大,细胞增大和开始分裂。培养两周后,开始形成瘤状愈伤组织。在愈伤组织中有形成层状分生组织、维管组织结节和分生细胞团。培养四周后,表层的分生细胞团分化形成大量芽原基,同时愈伤组织深层也出现分生细胞团。带节茎段可从切口两端的愈伤组织分化形成芽,亦可从叶腋的潜伏芽直接形成芽。 相似文献
13.
Terence M. Murphy 《Phytochemistry》1978,17(3):439-443
Ribulosebisphosphate carboxylase molecules from over 50 species of angiosperms and gymnosperms have been compared by quantitative microcomplement fixation, using antisera prepared against tobacco and spinach enzymes. There were close antigenic similarities between tobacco enzyme, enzymes from other members of the Solanaceae, and enzymes from members of the Nolanaceae, Cuscutaceae, and Convolvulaceae. There were relatively close similarities between spinach enzyme and enzymes from two other members of the Chenopodiaceae. There were relatively great differences between tobacco enzyme, spinach enzyme, and most other enzymes tested. The enzymes from most of the angiosperms tested were as different from tobacco enzyme and almost as different from spinach enzyme as were the enzymes from the gymnosperms. 相似文献
14.
种植青蒿与野生青蒿精油成分对比分析 总被引:1,自引:0,他引:1
用水蒸气蒸馏法和GC-MS法对来源于重庆云阳的栽培青蒿和野生青蒿精油的化学成分进行分析.从冬季和春季栽培的青蒿精油中分别鉴定出29和28个化合物,野生青蒿精油中鉴定出21个化合物.3种精油的化学成分差别明显,两种栽培青蒿精油有16个化合物相同.而栽培青蒿与野生青蒿精油仅有6个化合物相同.这表明基因型对青蒿精油的组成起决定作用;而气候因素对各成分的相对含量有重要影响,尤其对蒿酮和樟脑的积累影响较大.本文对进一步研究青蒿精油中萜类化合物之间的生源关系具有一定的参考价值. 相似文献
15.
Microorganisms capable of growth at 7 C were enumerated and isolated from soil samples from the manufacture and assembly areas of the Viking spacecraft. Populations ranging from 4.2 X 10(3) to 7.7 X 10(6)/g of soil were isolated from the 15 soil samples examined. Temperature requirements were determined, and those growing at 3 C, but not at 32 C, were designated as obligate psychrophiles in this investigation. Populations of soil bacteria, including aerobic sporeformers, ranging from 1.5 X 10(2) to 9.8 X 10(5)/g were capable of growth at 3 C, but not at 32 C. Bacterial isolates were identified to major generic groups. No psychrophilic sporeformers were isolated from soil from the manufacture area, but psychrophilic sporeformers ranged from 0 to 6.1 X 10(3)/g from soil from the assembly area. 相似文献
16.
分离自黑茶的散囊菌属真菌中的NRPS基因的检测和分布 总被引:1,自引:0,他引:1
【目的】检测源自黑茶的散囊菌属分离菌株中的NRPS基因,推测它们相应的次级代谢产物合成能力,并考察了基于NRPS基因分布特征进行散囊菌属真菌遗传多样性分析的可能性。【方法】运用IQS法提取来自湖南、四川和湖北等地黑茶样品的14株散囊菌(Eurotium spp.)菌株的总DNA,利用特异性引物对菌株中11种NRPS基因片段进行PCR检测和序列分析,并结合UPGMA法分析了NRPS基因的分布。【结果】各菌株分别含有4 10个NRPS基因片段。NRPS7、CPS1基因在所有菌株中都可以检测到,而NRPS2、NRPS6基因则仅在个别菌株中检测到;其它NRPS基因的分布则呈现出多样性。来自同一块砖茶的菌株Fw-30813-7、Fw-30813-4、Fw-30813-1和Fw-30925-5之间,NRPS1、NRPS2、NRPS3、NRPS4和NRPS8五个基因的分布存在差异,显示出黑茶内散囊菌的遗传多样性。来自湖南白沙溪茶厂的茯砖样品的菌株Fa-20719-3不含有NRPS5和NRPS8基因;而从湖南益阳茶厂茯砖茶7个分离菌株中均含有这两种基因。不同地点加工出来的黑茶样品中的散囊菌菌株之间存在一些明显的遗传差异。【结论】首次从我国黑茶中的散囊菌属分离菌株中检测到NRPS基因,并推测了NRPS产物的多样性,展示了其多样化分布特征,提示NRPS基因的分析有可能成为衡量散囊菌遗传多样性的另一个尺度。 相似文献
17.
G. Hernández A. Buonamici K. Walker G. G. Vendramin C. Navarro S. Cavers 《Conservation Genetics》2008,9(2):457-459
We describe 9 primers for amplification of microsatellite loci for the Neotropical tree Cedrela odorata L. (Meliaceae). Loci were isolated from an enriched library derived from a single DNA sample from a tree in Costa Rica. Levels
of polymorphism were determined using samples from a large progeny trial. Across loci, the number of alleles ranged from 14
to 30. Observed heterozygosity levels ranged from 0.61 to 0.88. No linkage disequilibria were detected although some departures
from Hardy-Weinberg equilibrium (HWE) were found, probably due to a Wahlund effect. 相似文献
18.
健康与龋病口腔唾液中乳杆菌的发酵类群与表面性质 总被引:2,自引:0,他引:2
目的 研究口腔健康的成年人和龋病患者唾液中乳杆菌的发酵类群和表面性质。方法 糖酸以口腔健康的成年人和龋病患者为对象,取其早餐后2 h的无刺激全唾液分离乳杆菌,检验其对葡萄糖和葡萄糖酸钠发酵的情况;应用MATH(Microbiol Adhesion to Hydrocarbons)法测定菌体表面疏水性和电荷。结果 口腔健康的成年人与龋病患者唾液中乳杆菌各发酵类群的比例不同,前者表面疏水性和电荷比较高,后者比较低。结论 口腔健康的成年人和龋病患者唾液中乳杆菌的组成不同,表面性质也不同,特定种类的乳杆菌与龋病的发展相关。 相似文献
19.
J. T. Silverstein W. K. Hershberger 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,90(5):733-739
Genetic parameters of size through sexual maturity have been relatively unexplored for Pacific salmon. In this study, individually tagged coho salmon were raised in freshwater, and the heritabilities of size and growth rate were estimated at several intervals between 13 and 24 months of age (spawning). Heritability estimates for size were moderate to high from 13 to 19 months of age, ranging from 0.36 to 0.50, and lower from 21 months to spawning at 24 months, ranging from 0.17 to 0.32. Heritabilities of specific growth rates estimated over 3-month intervals were moderate from 16 to 21 months of age, ranging from 0.21 to 0.34. Genetic and phenotypic correlations between sizes measured at different ages were moderate to high, ranging from about 0.7 to 1.0. Correlations between growth rate and size indicated that the larger fish were the fastest growing between 16 and 19 months of age and were slower growing between 19 and 21 months of age. 相似文献
20.
The occurrence and character of different types of ectomycorrhizas of birch seedlings were investigated in soils from three
naturally regenerating birch stands: a forest site, a clear-cut site, and a site recently disturbed by plowing. Birch grown
in soil from an evergreen broad-leaved forest without birch was also studied. The rate of ectomycorrhizal formation in the
soil from the evergreen broad-leaved forest was lower than that in the soil from the other three sites. The ectomycorrhizal
formation of seedlings grown in soil from the clear-cut and plowed sites were the same as or higher than that in soil from
the birch forest site. The largest number of ectomycorrhizal types were formed in soil from the birch forest site. In the
soil from the plowed site, only one type of ectomycorrhiza was formed, and it was different from the dominant type formed
in soils from the birch forest site and the clear-cut site. The results of this investigation showed that equal levels of
ectomycorrhizas were formed in soils from the different birch stands, but the types formed were different among those sites.
It is likely that the different ectomycorrhizal fungi were better adapted to the soil conditions at each of those sites. 相似文献