冬虫夏草不同部位来源的菌株及多次传代固体发酵特性

从西藏新鲜冬虫夏草不同部位分离菌株,并进行固体培养,比较菌丝生长、分生孢子产生情况及不同传代次数菌株的固体培养特性,以获得产生分生孢子数量最多的菌株用于蝙蝠蛾幼虫的侵染。结果表明：单子囊孢子、双子囊孢子和多子囊孢子菌株在斜面上出草能力较好,固体发酵时菌丝生长旺盛,分生孢子产生较多,显著高于组织分离菌株;组织分离菌株中,子座来源的菌株在谷壳和泥炭土培养基中,其产孢能力高于虫体来源的菌株;多次传代（5次传代）菌株在固体斜面上有较明显的退化现象,但在液体及固体发酵方面有着较好的生长以及分生孢子产量。     

羊肚菌不同单孢及不同萌发孔菌丝间的遗传多样性

本研究对来自不同单孢和不同萌发孔菌丝的166份羊肚菌菌株进行形态研究、交配型基因检测、基于ISSR的遗传多样性分析和菌株杂交选育。结果表明,来自不同单孢及其不同萌发孔菌丝培养的菌株间均存在不同程度的形态和遗传差异。4条ISSR引物共扩增出条带清晰的22条多态性谱带,多态性比率为88%。基于遗传相似性系数（GS）、不加权成对群算术平均法（UPGMA）构建的系统树,可将供试菌株分为梯棱羊肚菌Morchella importuna和六妹羊肚菌M. sextelata两大类群。聚类分析发现不同物种间的单孢菌株和单丝菌株的遗传差异显著;同一单孢不同萌发孔菌丝的菌株间存在较大的遗传分化,遗传多样性丰富。交配型基因检测证实羊肚菌是异宗结合型真菌,同一单孢的不同萌发孔菌丝体含相同的交配型基因（MAT 1-1-1或MAT 1-2-1）。遗传多样性结果表明：梯棱羊肚菌比六妹羊肚菌的遗传背景更广泛。此外,ISSR分子标记也表明仅依靠菌丝和菌核的形态特征并不能准确衡量羊肚菌菌株间的亲缘关系。研究羊肚菌单孢菌株、单丝菌株间的形态和遗传特征,将为羊肚菌优质菌种的精准选育提供理论参考。     

不同地理株中肋骨条藻生长特性及RAPD多态性

通过对不同地理株骨条藻形态和亚显微结构的观察和描述 ,鉴定为中肋骨条藻 ,但发现在刺长、细胞间隙、细胞链形态、链上细胞数 ,色素体个数方面存在差别 ;通过不同 N∶ P营养盐实验 ,结果表明 ,在 N∶ P为 16∶ 1时 ,东海株和胶州湾株中肋骨条藻均得到最大生长率 ,分别为 1.6 6 d1 和 1.5 3d- 1 ,东海株中肋骨条藻最大生长率要高于胶州湾株中肋骨条藻 ,这表明在不同的海域环境条件下 ,中肋骨条藻的生长均有各自地域性特征。应用 RAPD技术对两地理株中肋骨条藻进行鉴别 ,以其全 DNA为模板进行 RAPD扩增 ,两不同地理株的中肋骨条藻表现不同的 DNA多态性 ,同样以各自的小亚基片段为模板进行的 RAPD扩增条带也表现出差异性。实验结果表明 ,两株中肋骨条藻应为种下的不同变种或亚种     

Circulation of methicillin-resistant staphylococci in hospitals with different profiles

Analysis of prevalence of methicillin-resistant staphylococci in hospitals with different specializations was performed. 2584 strains were isolated. Methicillin-resistant (MR) strains were present in different profile hospitals and their total prevalence between isolated strains was 12.3% while significantly varied in different hospitals (from 8% to 37%). Along with MRSA (methicillin-resistant Staphylococcus aureus), MRSE (methicillin-resistant Staphylococcus epidermidis) and MRSS (methicillin-resistant Staphylococcus saprophyticus) were presented in all studied hospitals. The prevalence of MR strains was highest among strains isolated from flame burn wounds (37%), while in samples from newborns in maternity hospital resistant strains represented 12% of isolates, and in general clinical hospital--not more than 9% of isolates. Relationship between rates of isolation of methicillin-resistant staphylococci and specialization of hospital unit was noted. For example, prevalence of MR staphylococci in isolates from newborns in ICU (47.5%) differed from the same one in maternity hospital (11.6%).     

寄主和分布区系不同的球孢白僵菌菌株近缘关系的研究

观察、测定了来源不同的球孢白僵菌 1 9个菌株的培养性状、产孢量、萌发中时、水分活性、紫外照射活率、水浴活率等指标 ,将培养性状编码后 ,由所得的 8个指标对供试菌株求相关系数矩阵 .分析表明 ,不同菌株近缘关系的远近主要由菌株原始分布区系距离远近所决定 ,受寄主不同的影响次之 .来源于相同 (或相近 )地区的菌株相关系数可达极显著水平 ,而从相同寄主角度分析 ,得到菌株间的相关系数有高有低 ,多表现为相关不显著     

Variations in maxi-circle and mini-circle sequences in kinetoplast DNAs from different Trypanosoma brucei strains

We have compared a total of 30 recognition sites for eight restriction endonucleases on the 20-kilobase-pair maxi-circle of kinetoplast DNAs from five different Trypanosoma brucei strains. In addition to three polymorphic sites were have found a 5 kilobase-pair region that is not cleaved by any of the eight enzymes and that varies in size over 1 kilobase pair in the strains analysed. Mini-circles from these five strains, digested with endonuclease TaqI or MboII, yield very complex fragment patterns, showing that extensive mini-circle sequence heterogeneity is a common characteristic of these T. brucei strains. The size distribution of mini-circle fragments in these digests was identical for different clones of the 427 strain, but very different for mini-circles from different strains. These results show that maxi-circle sequence is conserved, whereas mini-circle sequence is not. Restriction digests of maxi-circles could be useful in determining how closely two Trypanosoma strains are related, whereas mini-circle digests can serve as sensitive tags for individual strains.     

不同幽门螺杆菌菌株ureB和hspA基因同源性分析

目的研究不同来源幽门螺杆菌菌株的ureB基因和hspA基因的同源性。方法在GenBank中调取全球来源于幽门螺杆菌不同菌株的ureB基因序列23个和中国境内来源于幽门螺杆菌不同菌株的hspA基因序列20个,利用ClustalW2生物软件,分别对ureB基因和hspA基因序列进行同源性比较分析,并建立基因进化树,分析其特点。结果不同国家之间ureB基因序列并不一致,同一国家ureB基因序列相似性较高;中国境内hspA基因序列相似性程度很高。结论中国境内不同幽门螺杆菌菌株ureB基因序列和hspA基因序列的相似性程度都很高,都具有很高的同源性。     

Variations in virulence between different electrophoretic types of Listeria monocytogenes

A total of 245 strains of Listeria monocytogenes, representing 33 different electrophoretic types (ETs), were examined quantitatively for haemolytic activity. No significant difference was observed in the mean haemolytic activity between different ETs. Eighty four out of 91 strains examined were found to be virulent for chick embryos. Strains belonging to ET 2 and ET 4 were found to be less virulent than strains of other ETs (P = 0.0447). Furthermore, strains from clinical cases were found to be more virulent (P = 0.0002) than strains from foods (the MTD among clinical strains was 2.46 in mean compared with 3.64 among food isolates). The explanation for this may be that more virulent strains are more prone to cause human infection. It is, however, also possible that strains of L. monocytogenes may become more virulent while multiplying in a living organism compared with multiplying in foods.     

Inactivating effect of N-methyl-N'-nitro-N-nitrosoguanidine on yeasts with different ploidies]

Haploid and diploid strains of Saccharomyces cerevisiae, Sacch. ellipsoideus and Pichia pinus were studied. Differences in N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) sensitivity were detected both between haploids and diploids of the same species and between the corresponding strains of different species. Survival curves after MNNG treatment of all strains irrespectively of ploidy were exponential with "a tail". All the strains also exhibited the delayed appearance of clones from MNNG-treated cells. Three different forms of cell inactivation after MNNG treatment were detected similar to those observed after irradiation.     

Phenotypic and genetic diversity of Paenibacillus azotofixans strains isolated from the rhizoplane or rhizosphere soil of different grasses

Fifty-three strains identified as Paenibacillus azotofixans were isolated from the rhizoplane and rhizosphere of different grasses and from soil. To study the diversity within this species, four approaches were used: assessment of homology with a nifKDH probe in hybridization experiments; use of a selected 20-mer primer to produce RAPD profiles and of BOX-PCR to generate genomic fingerprintings; and phenotypic tests using the API50CH system. The API tests performed with the 53 P. azotofixans strains showed that all strains produced acid from 15 carbohydrates; using six other carbohydrates (sorbitol, dulcitol, tagatose, starch, glycogen and D -arabitol), the strains could be divided in five groups of related strains. All strains tested showed homology to Klebsiella pneumoniae nifKDH genes, resulting in 14 different hybridization patterns with this probe. Using RAPD-fingerprinting with one appropriate primer, 23 different amplification patterns were observed. The BOX-PCR approach confirmed the grouping suggested by the RAPD fingerprinting. A comparison of the 53 strains by similarity matrix analysis using the data obtained in all approaches resulted in a phenogram, grouping them into five broad groups at 74% similarity and into 27 subgroups at 94% similarity. At 100% similarity, 31 groups of strains could be formed, indicating a high degree of diversity among the strains tested. Overall, the diversity was independent from the origin of strains, since a variety of different groups was isolated from each plant studied. However, some clusters were dominant in wheat and sugarcane samples. The results indicated that the methods used here are sensitive indicators of diversity among the strains studied and can be applied as efficient and reliable means for further ecological and biogeographical studies.     

Genomic Relatedness of Clostridium difficile strains from different toxinotypes and serogroups

Clostridium difficile strains can be divided into sixteen toxinotypes (0 and I to XV) according to changes in their toxin genes. To determine the genomic similarity between toxinotypes, two molecular typing techniques were used, AP-PCR and PFGE. Strains were selected from five serogroups (A1, A15, E, F, X) and represented non-toxinogenic isolates, strains with toxin genes identical to the reference C. difficile strain, VPI 10463 (toxinotype 0), and strains with variant toxin genes from toxinotypes III, IV, V, VI, VII, VIII, IX, and XI. The strains studied formed three main clusters, which correlated well with serogroups: in the first were strains from serogroup A15 and E; in the second, serogroup A1 strains; and in the third, strains from serogroups F and X. Within these three clusters strains of a single toxinotype were grouped together. Toxinotypes III, IV and VIII were more similar to strains with ordinary toxin genes or non-toxinogenic isolates within the same serogroup than to other toxinotypes. Toxinotypes V, VI, VII, and XI, which exhibit similar changes in their toxin genes, seem to be more closely related one to another than to other toxinotypes. It can be concluded that variant Clostridium difficile strains do not have a common ancestor and that groups of different toxinotypes arose independently from strains with ordinary toxin genes.     

Multilocus microsatellite typing shows three different genetic clusters of Leishmania major in Iran

Ten polymorphic microsatellite markers were used to analyse 25 strains of Leishmania major collected from cutaneous leishmaniasis cases in different endemic areas in Iran. Nine of the markers were polymorphic, revealing 21 different genotypes. The data displayed significant microsatellite polymorphism with rare allelic heterozygosity. Bayesian statistic and distance based analyses identified three genetic clusters among the 25 strains analysed. Cluster I represented mainly strains isolated in the west and south-west of Iran, with the exception of four strains originating from central Iran. Cluster II comprised strains from the central part of Iran, and cluster III included only strains from north Iran. The geographical distribution of L. major in Iran was supported by comparing the microsatellite profiles of the 25 Iranian strains to those of 105 strains collected in 19 Asian and African countries. The Iranian clusters I and II were separated from three previously described populations comprising strains from Africa, the Middle East and Central Asia whereas cluster III grouped together with the Central Asian population. The considerable genetic variability of L. major might be related to the existence of different populations of Phlebotomus papatasi and/or to differences in reservoir host abundance in different parts of Iran.     

Relationships between plasmids and phenotypes of presumptive strains of Vibrio anguillarum isolated from different fish species

On the basis of plasmid composition as well as serological and biochemical properties, 26 strains identified as Vibrio anguillarum isolated from diseased fish could be assigned to two different groups. Except for three reference strains, these++ strains were isolated from Norwegian fish. The four strains isolated from rainbow trout (Salmo gairdneri), the only strain isolated from char (Salvelinus alpinus), and three of six strains isolated from Atlantic salmon (Salmo salar) harbored a plasmid of 47 megadaltons (MDa). Restriction endonuclease analysis showed that this plasmid and the virulence plasmid pJM1, carried by V. anguillarum strain 775, were very similar but not identical. Strains harboring the 47-MDa plasmid had nearly identical biochemical properties and were serotype O1. Strains isolated from reared coastal cod (Gadus morhua), turbot (Scophthalmus maximus), halibut (Hippoglossus hippoglossus), free-living saithe (Pollachius virens), and partly from reared Atlantic salmon differed from strains harboring the 47-MDa virulence plasmid by not containing this plasmid, by having different biochemical traits, and by being serotype O2. Rainbow trout which were experimentally infected with a strain isolated from cod suffering from vibriosis developed clinical symptoms similar to those in cod but quite different from those usually seen in rainbow trout.     

Comparative morphological, ecological, and molecular studies of Aspergillus versicolor (Vuill.) Tiraboschi strains isolated from different ecotopes

Cultural, morphological, ecological, and trophic properties (growth at different temperatures and on various organic substrates), as well as molecular and genetic peculiarities of Aspergillus versicolor (Vuill) Tiraboschi strains of different origins, were determined. The strains were isolated from different ecotopes (upper horizons of modern soils of several geographic regions, ancient soils and peat, and permafrost). No essential distinctions in cultural and morphological properties were revealed between the strains. Strains obtained from peat of the Aleutian Islands were characterized by the highest radial rates of colony growth. Some variations in the ITS loci of rDNA were observed in strains isolated from different ecotopes; the distinctions were most pronounced (1.7%) in the strain isolated from 100 000-year-old permafrost.     

Comparative morphological, ecological, and molecular studies of Aspergillus versicolor (Vuill.) tiraboschi strains isolated from different ecotopes

Cultural, morphological, ecological, and trophic properties (growth at different temperatures and on various organic substrates), as well as molecular and genetic peculiarities of Aspergillus versicolor (Vuill.) Tiraboschi strains of different origins, were determined. The strains were isolated from different ecotopes (upper horizons of modern soils of several geographic regions, ancient soils and peat, and permafrost). No essential distinctions in cultural and morphological properties were revealed between the strains. Strains obtained from peat of the Aleutian Islands were characterized by the highest radial rates of colony growth. Some variations in the ITS loci of rDNA were observed in strains isolated from different ecotopes; the distinctions were most pronounced (1.7%) in the strain isolated from 100 000-year-old permafrost.     

Oocyte spontaneous activation in different rat strains

Oocyte spontaneous activation (OSA) has been reported to occur during in vitro culture of ovulated rat oocytes. The objective of this study was to compare the rate of oocyte spontaneous activation and the level of maturation promoting factor (MPF) activity in oocytes from different strains. Twelve strains were selected from two commercial sources. Females were superovulated and oocytes collected 17 h after hCG injection. Denuded oocytes were cultured in M16 medium under oil at 37 degrees C and 5% CO(2) in air. The proportion of activated oocytes was determined after 6 h of in vitro culture. Data were compared by analysis of variance (ANOVA), considering each animal as an experimental unit. MPF activity was determined in oocytes from the different strains at 0, 1.5, and 3 h after oocyte collection. The log ratio of the MPF activity at 1.5 and 3 h relative to 0 hours for each animal was analyzed by ANOVA. While significant (p < 0.01) differences were observed between strains in the rate of OSA, there were no differences between strains in the level of MPF during the time points measured (p > 0.3).     

Relationships between plasmids and phenotypes of presumptive strains of Vibrio anguillarum isolated from different fish species.

On the basis of plasmid composition as well as serological and biochemical properties, 26 strains identified as Vibrio anguillarum isolated from diseased fish could be assigned to two different groups. Except for three reference strains, these++ strains were isolated from Norwegian fish. The four strains isolated from rainbow trout (Salmo gairdneri), the only strain isolated from char (Salvelinus alpinus), and three of six strains isolated from Atlantic salmon (Salmo salar) harbored a plasmid of 47 megadaltons (MDa). Restriction endonuclease analysis showed that this plasmid and the virulence plasmid pJM1, carried by V. anguillarum strain 775, were very similar but not identical. Strains harboring the 47-MDa plasmid had nearly identical biochemical properties and were serotype O1. Strains isolated from reared coastal cod (Gadus morhua), turbot (Scophthalmus maximus), halibut (Hippoglossus hippoglossus), free-living saithe (Pollachius virens), and partly from reared Atlantic salmon differed from strains harboring the 47-MDa virulence plasmid by not containing this plasmid, by having different biochemical traits, and by being serotype O2. Rainbow trout which were experimentally infected with a strain isolated from cod suffering from vibriosis developed clinical symptoms similar to those in cod but quite different from those usually seen in rainbow trout.     

Screening of different contaminated environments for polyhydroxyalkanoates-producing bacterial strains

Total sixteen bacterial strains were isolated and purified from the samples collected from sugarcane molasses soil, sewage water and long-chain-hydrocarbon-contaminated area of the Punjab University, Lahore, Pakistan. Tolerance to different antibiotics was studied and strains showed multiple antibiotic resistance. All strains were characterized for Gram stain, biochemical reactions and polyhydroxyalkanoate (PHA) production. Total fourteen strains were Gram negative and two were Gram positive, while biochemically nine PHA producers showed affiliation to Pseudomonas, Enterobacter, Citrobacter, Bacillus and Escherichia. Screening for PHA production was done by Sudan black staining and nine out of sixteen strains exhibited PHA producing ability. PHA production was optimized for different growth parameters, like nitrogen concentration, pH and temperature. PHA extraction was done by solvent extraction method. Bacterial strains US1 and M1 accumulated up to 30% PHA of their cell dry weight on PHA extraction by solvent extraction method. Bacterial strain US1 was identified by 16S rRNA gene analysis as P. aeruginosa (DQ455691). PHA production was confirmed by PCR amplification of 500 bp fragment from PHA polymerase (Pha C) gene; five strains from nine PHA producers gave positive results on PCR. Pha C gene fragment of US1 was sequenced and submitted to Gene Bank under the accession number DQ455690. The amino acid sequence showed homology using the protein BLAST at 129–132 sites with different PHA synthases of the Pseudomonas sp.     

Immunochemical reactivity of Aspergillus fumigatus antigens from different sources

We have studied the immunochemical and biochemical differences in 12 Aspergillus fumigatus strains isolated from different sources. The enzymatic activity of all these strains were studied by a rapid enzyme detection method (API-ZYM). One of 12 strains studied produced alkaline phosphatase, while two produced chymotrypsin, and three produced trypsin. By SDS-PAGE we studied proteins present in the antigen extracts from all 12 strains. Several of the protein bands were unique and may be used to differentiate the strains. One such protein is the 58 kDa band present in the mycelial extract and the 33 kDa in the culture filtrate. By crossed immunoelectrophoresis, differentiation of the strains isolated from cystic fibrosis patients can be made based on a few specific precipitin arcs developed against anti-Aspergillus rabbit serum.     

不同红树林地区老鼠簕内生放线菌的分离及其环境适应性

【目的】比较不同红树林地区的老鼠簕内生放线菌的地理分布,了解内生放线菌与其所处环境的相关性。【方法】分别从5个不同地点的红树林采集老鼠簕全株植物,采用9种分离培养基,从植株不同部位分离内生放线菌,用16S rRNA基因序列分析鉴定到属,用添加不同NaCl浓度的ISP 2液体培养基进行耐盐度测试,用无氮基础培养基进行固氮活性测试。【结果】共分离得到内生放线菌52株,其中从叶、茎和根部分别获得5株、2株和45株,花和果中未分离到。52株内生放线菌分别属于小单孢菌属(47株),链霉菌属(3株),疣孢菌属(1株)和继生菌属(1株)。48株菌表现出耐盐或嗜盐特征,其中18株最高耐盐度20%,4株不能在无盐条件下生长,12株菌可在含有3.3%NaCl的培养基上生长良好。4株菌可在无氮培养基下生长。【结论】对47株内生小单孢菌的地理分布分析表明,老鼠簕内生小单孢菌的类群因不同地理位置有很大差异。耐盐和固氮活性测试结果表明了老鼠簕内生放线菌对环境的适应性。