安徽铜陵河流附生细菌多样性

通过对铜陵地区不同河段的上覆水和沉积物的理化性质进行分析,结合聚合酶链式反应-变性梯度凝胶电泳（PCR-DGGE）的方法,研究了铜陵不同河段中附生细菌的多样性及其与环境因子的关系。结果表明,8个河段中上覆水和沉积物的营养水平及重金属含量存在较大差异,不同河段附生细菌的多样性指数也存在差异。数据分析表明,铜陵河流中黄浒河附生细菌的多样性最高,顺安河下游和钟仓河附生细菌的多样性最低。这种差异主要与河段间上覆水和沉积物不同的营养水平、重金属含量水平等因素有关。附生细菌的香农-威纳多样性与上覆水中的氨态氮（NH3-N）、总氮（TN）、总磷（TP）、可溶性正磷酸盐（PO3-4-P）和高锰酸盐指数（COD Mn）呈显著或极显著负相关,与沉积物中镉（Cd）、铜（Cu）和锌（Zn）的含量具有显著或极显著正相关性。     

Environmental adaptation and genetic variations in geographically isolated Emma field crickets Teleogryllus emma (Orthoptera: Gryllidae)

The Emma field cricket, Teleogryllus emma (Ohmachi & Matsuura), distributed between 43°N and 30°N in the Japanese archipelago, is univoltine and overwinters in the egg stage. Its eggs hatch on the slope of the Oishi Dam (38.03°N, 139.57°E, 160–170 m a.s.l.) in late June, adults begin emerging from late August, and oviposition lasts until early October. Oviposition is limited to the period when the water level of the Oishi Dam is low. The period from egg hatching to adult emergence is approximately 1 month shorter than that of the T. emma population on the Arakawa riverside (38.09°N, 139.57°E, 29 m a.s.l.), which is approximately only 7 km from the Oishi Dam. The egg and body sizes of T. emma on the slope of the Oishi Dam were smaller than those of T. emma on the Arakawa riverside, and the egg and nymphal periods were shorter; these variations were inherited by the next generation of T. emma. The egg period, nymphal period and head width of T. emma on the dam slope correspond to those of the populations near 40°N. Several traits of the T. emma population on the dam slope were naturally selected by adapting to the isolated environment, resulting in the genetic variations. However, their variations were small and the period after isolation is short, suggesting that it is in the early stages of speciation.     

沉水植物附着细菌群落结构及其多样性研究进展

与陆生植物类似,沉水植物的叶表也存在着大量的附着细菌。附着细菌拥有独特的生态位和显著的生态功能,与沉水植物构成了复杂的共生体系。针对附着细菌的群落结构及其多样性进行了简单的综述。在方法学上,"表面活性剂+超声处理"的方式能够比较有效地洗脱叶表的附着细菌。显微计数和分离培养的方法分别发现,某些沉水植物附着细菌的多度在105~107个/cm2以及106 CFU/cm左右。克隆测序的研究表明沉水植物附着细菌的OTU在几十到上百的范围内。在群落结构上,Betaproteobacteria、Bacteroidetes、Alphaproteobacteria、Actinobacteria、Planctomycetes、Cyanobacteria等门类的细菌较为常见。先锋物种在附着细菌生物膜的形成过程中发挥着关键作用,环境条件和植物体都会对附着细菌的多样性造成影响。富营养化水体观察到较高的附着细菌丰度,溶解性有机物比无机营养物更加适合附着细菌的利用。植物体的叶片化学组成、渗出物以及物理结构等会影响附着细菌的多样性及群落结构。对沉水植物附着细菌群落结构形成的机理进行了假说性质的总结,并对附着细菌的研究前沿进行了展望。     

Biodegradation of alkylpyridines by bacteria isolated from a polluted subsurface

Ten bacterial strains were isolated fromalkylpyridine polluted sediments 7.6 m below thesurface. These strains were able to degrade 11different alkylpyridine isomers. Degradation ratesdepended on number and position of the alkyl group. Isomers with an alkyl group at position 3 were moreresistant to microbial attack. Of the 10 strains, 6isolates were selected for detailed study. Theseisolates mineralized the isomers to CO₂,NH₄ ⁺, and biomass. All strains weregram-negative rods with a strict aerobic metabolism. Characterization of physiological and biochemicalproperties revealed similarity between strains. Eeachstrain however, had a limited substrate range whichenabled it to degrade no more than 2 to 3 compounds ofthe 14 alkylpyridine isomers tested. Examination ofthe genetic variability among cultures with therandomly amplified polymorphic DNA technique revealedhigh levels of genomic DNA polymorphism. The highestsimilarity between 2 strains (0.653) was observedbetween 2-picoline and 3-picoline degrading cultures. The molecular basis of the differences in substratespecificity is under investigation.     

Polyphenolic compounds on leaves limit iron availability and affect growth of epiphytic bacteria

Polyphenolic compounds produced by plants can chelate iron, reducing its bioavailability to plant‐associated bacteria. In response to limited iron levels, most bacteria produce siderophores to acquire needed iron quantities. The amount of phenolic compounds detected in methanolic washings of leaves of different plant species varied greatly, being nearly sevenfold higher in Viburnum tinus than in Phaseolus vulgaris. In species with high levels of total phenolics (e.g. Pelargonium hortorum), tannin concentration of leaf washings was also high and accounted for up to 85% of total phenolics. Both stimulation of production of the siderophore pyoverdine in Pseudomonas syringae strain B728a and inhibition of growth of an isogenic mutant I‐1, deficient in pyoverdine production were associated with plants harbouring high levels of leaf surface phenolics. Levels of tannic acid sufficient to inhibit growth of the pyoverdine mutant in culture in an iron‐reversible fashion were similar to tannin levels found on leaves of plants such as P. hortorum. Additionally, the amount of pyoverdines produced by P. syringae and quantified in leaf washings from a variety of plants was directly related to the concentration of tannins released from the leaf, indicating that tannins were responsible for sequestering iron. Phenolic compounds, principally tannins, may thus play an important role in plant–microbe interactions.     

南海南沙海域沉积物中可培养微生物及其多样性分析

【目的】为了从南沙海域中分离获得微生物菌种资源,【方法】本文通过沉积物采样、可培养菌分离及16S rRNA鉴定,【结果】从22个站点的沉积物样品中获得349株细菌,分属于87个种。发现产芽孢细菌分布最广,并在10个站点的分离株中占多数;它们是Bacillus,Halobacillus,Brevibacillus,Paenibacillus,Pontibacillus和Thalassobacillus。其中芽孢杆菌（Bacillus）无论在数量上还是种类上都最多,分别属于34种,其中有8个可能的新种。此外,g-Proteobacteria是分离率较高的另一亚群;其中,假单胞菌（Pseudomonas）,海杆菌（Marinobacter）,食烷菌（Alcanivorax）属的细菌最多。统计还发现,在深度750~2000 m之间,低GC含量的细菌最丰富,而深度2000 m以下,分离株则全部为g-Proteobacteria。【结论】南沙沉积物可培养微生物中产芽孢细菌及 g-Proteobacteria比较丰富;其中,产芽孢细菌的多样性最高,具有进一步研究开发价值。     

Plant-microbe interactions: identification of epiphytic bacteria and their ability to alter leaf surface permeability

Bacteria were either isolated from leaf surfaces of Hedera helix or obtained from a culture collection in order to analyse their effect on barrier properties of isolated Hedera and Prunus laurocerasus cuticles. On the basis of the 16S rDNA sequences the genera of the six bacterial isolates from Hedera were identified as Pseudomonas sp., Stenotrophomonas sp. and Achromobacter. Water permeability of cuticles isolated from H. helix was measured before and after inoculation with the six bacterial strains. In addition water permeability of cuticles isolated from P. laurocerasus was measured before and after inoculation with the three bacterial strains Pseudomonas aeruginosa, Xanthomonas campestris and Corynebacterium fascians. Rates of water diffusing across isolated cuticles of both species significantly increased by up to 50% after inoculation with all bacterial strains. Obtained results show that epiphytic bacteria have the ability of increasing water permeability of Hedera and Prunus cuticles, which in turn should increase the availability of water and dissolved compounds in the phyllopshere. Consequently, living conditions in the habitat phyllosphere are improved. It can be concluded that the ability to change leaf surface properties will improve epiphytic fitness of leaf surface bacteria.     

Screening of bacteria, isolated from PAH-contaminated soils, for production of biosurfactants and bioemulsifiers

Fifty-seven bacterial strains were isolated from PAH-contaminated soils using PAH-amended minimal medium. The isolates were screened for their production of biosurfactants and bioemulsifiers when grown in liquid media containing selected PAHs. The results suggest that many, but not all, of the isolates are able to produce biosurfactants or bioemulsifiers under the experimental conditions. The majority of the strains isolated on phenanthrene, pyrene, and fluoranthene were better emulsifiers than surface tension reducers and the stability of the formed emulsions was in general high. The strains isolated on anthracene were in general better in lowering the surface tension than in forming emulsions. In all strains, reduction of surface tension and emulsion formation did not correlate. However, in the majority of strains the two factors were associated with the bacterial cell surfaces, rather than the culture supernatants. Nevertheless, supernatants from selected surfactant-producing anthracene isolates increased the aqueous solubility of anthracene. Although a significant potential for surfactant and emulsifier production in the microbiota of the PAH-contaminated soils was found in this study, the ability of individual strains to mineralize PAHs did not coincide with production of surface-active compounds.     

Diversity and osmoregulatory responses of bacteria isolated from two-phase olive oil extraction waste products

Six phenotypically distinct groups of bacteria were isolated from Spanish and Greek sources of alpeorujo, the waste from two-phase decanter, continuous extraction olive oil mills. These different bacteria isolated from alpeorujo showed different growth and osmoregulatory responses to conditions of reduced water activity (a_w), and there was a correlation between the ability of isolates to withstand low a_w and grow on alpeorujo. One isolate (1A), which grew particularly well both on alpeorujo and in nutrient broth containing either 10% NaCl or 30% sucrose, was identified as being most closely related to Bacillus amyloliquifaciens using biochemical tests and partial 16S rDNA gene sequence analysis. Bacillus sp. strain 1A was found to display an atypical membrane lipid response at low a_w since the major change was an increase in the zwitterionic phosphatidylethanolamine rather than an anionic phospholipid such as phosphatidylglycerol. In addition, instead of the expected decrease, there was an increase in the average lipid fatty acid acyl chain length at low a_w without any other compensatory fluidizing change. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mn accumulation in a submerged plant Egeria densa (Hydrocharitaceae) is mediated by epiphytic bacteria

Many aquatic plants act as biosorbents, removing and recovering metals from the environment. To assess the biosorbent activity of Egeria densa, a submerged freshwater macrophyte, plants were collected monthly from a circular drainage area in Lake Biwa basin and the Mn concentrations of the plants were analysed. Mn concentrations in these plants were generally above those of terrestrial hyperaccumulators, and were markedly higher in spring and summer than in autumn. Mn concentrations were much lower in plants incubated in hydroponic medium at various pH levels with and without Mn supplementation than in field‐collected plants. The precipitation of Mn oxides on the leaves was determined by variable pressure scanning electron microscopy‐energy dispersive X‐ray analysis and Leucoberbelin blue staining. Several strains of epiphytic bacteria were isolated from the field‐collected E. densa plants, with many of these strains, including those of the genera Acidovorax, Comamonas, Pseudomonas and Rhizobium, found to have Mn‐oxidizing activity. High Mn concentrations in E. densa were mediated by the production of biogenic Mn oxide in biofilms on leaf surfaces. These findings provide new insights into plant epidermal bacterial flora that affect metal accumulation in plants and suggest that these aquatic plants may have use in Mn phytomining.     

The properties of hydrocarbon-oxidizing bacteria isolated from the oilfields of Tatarstan, western Siberia, and Vietnam

Eleven strains of hydrocarbon-oxidizing bacteria, isolated from oilfields and representing the genera Rhodococcus, Gordonia, Dietzia, and Pseudomonas, were characterized as mesophiles and neutrophiles. Rhodococci were halotolerant microorganisms growing in a media containing up to 15% NaCl. All the strains oxidized n-alkanes of crude oil. An influence of the cultivation temperatures (28 or 45°C) and organic supplements on the degradation of C₁₂-C₃₀ n-alkanes in oxidized oil by two bacterial strains of the genus Pseudomonas was shown. The introduction of acetate, propionate, butyrate, ethanol, and sucrose led mainly to decreased oxidation of petroleum paraffins. At certain cultivation temperatures, the addition of volatile fatty acid salts increased the content of certain n-alkanes in oxidized oil as compared to crude oil.     

Peculiarities of adhesion of epiphytic bacteria on leaves of the seagrass <Emphasis Type="Italic">Zostera marina</Emphasis> and on abiotic surfaces

A comparative study of the adhesion of epiphytic bacteria and marine free-living, saprophytic, and pathogenic bacteria on seagrass leaves and abiotic surfaces was performed to prove the occurrence of true epiphytes of Zostera marina and to elucidate the bacterium-plant symbiotrophic relationships. It was shown that in the course of adhesion to the seagrass leaves of two taxonomically different bacteria, Cytophaga sp. KMM 3552 and Pseudoalteromonas citrea KMM 461, isolated from the seagrass surface, the number of viable cells increased 3–7-fold after 60 h of incubation, reaching 1.0–2.0 × 10⁵ cells/cm²; however, in the case of adhesion of these bacteria to abiotic surfaces, such as glass or metal, virtually no viable cells were observed after 60 h of incubation. Such selectivity of cell adhesion was not observed in the case of three other bacterial species studied, viz., Vibrio alginolyticus KMM 3551, Bacillus subtilis KMM 430, and Pseudomonas aeruginosa KMM 433. The amount of viable cells of V. alginolyticus KMM 3551 absorbed on glass and metal surfaces increased twofold after 40 h of incubation. The cells of saprophytic B. subtilis KMM 430 and pathogenic P. aeruginosa KMM 433 adsorbed on three studied substrata remained viable for 36 h and died by the 60th hour of incubation.     

Lindane degradation by root epiphytic bacterium Achromobacter sp. strain A3 from Acorus calamus and characterization of associated proteins

Abstract

Lindane degrading root epiphytic bacteria were isolated from wetland plant Acorus calamus. Bacterial strain A3 identified as Achromobacter sp. A3, showed maximum degradation potential of 88.7?±?1.24% for 50?mg?l^?1 lindane. Lindane biodegradation was followed by decrease in pH as well as increase in concentration of chloride ions in the culture medium. Lindane degradation potential of Achromobacter sp. A3 was also studied at different concentrations of lindane. Maximum degradation was at 10?mg l^?1 followed by 50?mg l^?1 and 100?mg l^?1 lindane. Also, lindane induced proteins were studied using SDS-PAGE. The induced proteins were identified as alpha/beta hydrolase fold-3 domain-containing protein, involved in lindane hydrolysis and extracellular solute-binding family protein having role in transmembrane transport of lindane for utilization of lindane by bacteria. The appearance of unique polypeptides in lane corresponding to media supplemented with lindane showed that the exposure of bacterial cells to lindane has resulted in regulative expression of certain proteins. So far as known, this is the first report to isolate and study lindane degrading root epiphytic bacteria from A. calamus.     

Secondary productivity (3H-Leucine and 3H-Thymidine incorporation), abundance and biomass of the epiphytic bacteria attached to detritus of Typha domingensis pers. in a tropical coastal lagoon

Senescent, naturally dried leaves of Typha domingensis were incubated inthe littoral region of a coastal lagoon and epiphytic bacterial volume,abundance, biomass and secondary productivity were measured during 127 daysof decomposition. The peak of cell abundance was registered at t =127 days when expressed per leaf surface area (10.07×10⁷cells cm^-2; 7.26 µgC cm^-2), and at t= 26 days when expressed per biofilm dry mass (38.10 ×10⁷ cells (mgDM biofilm)^-1, 30.52 µgC(mgDM biofilm)^-1). The highest values of bacterial biovolumesand lower turnover time were usually obtained in the beginning of thecolonization. Leu:Tdr ratios were also higher in the beginning of thecolonization, when bacterial community presented unbalanced metabolism.Consequently, the highest discrepancies between the bacterial secondaryproduction estimated by leu and Tdr incorporation were observed in the first2 days of decomposition. On average, the bacterial secondary productivityestimated by leu incorporation was 2.1 times higher than the valuesestimated by Tdr incorporation when the empirical factor for Tdr wasobtained from the relationship between Tdr and biomass increment. Thisdifference increased to 4.2 when the empirical factor was obtained from therelationship between Tdr and cell numbers increment. An average of bothmethods (0.0037 to 0.1397 µgC cm^-2 h^-1)produced results that fall within the range reported in the literature forepiphytic bacteria of freshwater ecosystems.     

印度洋表层海水石油降解菌的多样性分析

【目的】为了研究印度洋石油降解菌多样性,并获得新的石油降解菌。【方法】本研究通过印度洋表层海水样品采集、以柴油与原油1:1混合物作为碳源,从中富集、分离筛选石油降解菌,并通过PCR-DGGE对13个站点富集菌群的菌群结构进行分析。【结果】通过形态观察、生理生化反应和16SrRNA分析,共得到共29个属的51株不同的细菌,它们主要是属于α亚群和γ亚群。其中,Alcanivorax属(占18%),Novosphingobium属(占10%)和Marinobacter(占6%)Thalassospira(占6%)为主要的优势菌。通过生态多样性分析表明,Shannon-Winner指数(H)为4.57968,说明其具有较高的多样性;均匀度指数(E)为0.8664771,表示其分布比较均匀。单菌实验表明,49株具有石油降解能力其中,Sinomonas,Knoellia,Mesoflavibacter等属的细菌为首次发现有降解能力。DGGE分析表明Alcanivorax属的细菌是印度洋表层海水中的重要石油降解菌。【结论】本研究首次揭示了印度洋表层海水中石油降解菌的多样性,并获取了若干在海洋石油污染生物修复中具有应用前景的降解菌。     

Iodothyronine sulfate-hydrolyzing anaerobic bacteria isolated from human fecal flora

Abstract 23 Bacterial strains isolated from human fecal flora were screened for hydrolysis of iodothyronine sulfates. Three obligate anaerobic bacterial strains possessed sulfatase activity. Two strains were identified as Peptostreptococcus productus , the other strain probably belonged to the genus Eubacterium or Lachnospira . In anaerobic incubations with growing bacteria up to 78% of the iodothyronine sulfates were deconjugated in 24 h. Hydrolysis was dependent on the bacterial strains and on the iodothyronine sulfates tested. This study extents previous observations of similar iodothyronine sulfatase activities associated with bacteria from rat intestinal microflora [5]. By analogy, hydrolysis of iodothyronine sulfates by anaerobic bacteria from human intestinal microflora probably represents an exo-enzymatic process.     

烟草可培养内生细菌的分离及多样性分析

采用稀释平板法, 从健康烟草的根、茎、叶组织中分离到267株内生细菌。利用细菌菌落表征性状和16S rRNA序列对这些分离物进行了多样性分析。通过数值分析比较了8个菌落形态表征性状, 以类平均连锁聚类法的方式进行聚类分析, 在2.15的水平上可分成5个聚类群和56个亚群。16S rDNA序列系统发育分析表明267株分离物可分为21个类群。研究表明同一菌落形态类型的菌株在系统发育树中不一定聚为一类, 菌落形态分类与分子生物学方法分类结果不完全一致。经克隆测序分析表明, 这267株分离物分别与GenBank中6类细菌中的21个已知种相似性达到98%?99%。其中芽孢杆菌属(Bacillus)细菌是烟草可培养内生细菌的优势种群。     

Lactic acid bacteria isolated from canine faeces

AIMS: Lactic acid bacteria (LAB) were isolated and sequenced from the faeces of healthy dogs. Five of these strains were selected and further characterized to clarify the potential of these strains as probiotics for canine. METHODS AND RESULTS: LAB were found in 67% (14/21) of the canine faeces samples when plated on Lactobacilli Selective Media without acetic acid. Out of 13 species identified with partial 16S rRNA gene sequencing, Lactobacillus fermentum LAB8, L. mucosae LAB12, L. rhamnosus LAB11, L. salivarius LAB9 and Weissella confusa LAB10 were selected as candidate probiotic strains based on their frequency, quantity in faeces, growth density, acid tolerance and antimicrobial activity. The minimal inhibitory concentration values of these isolates were determined for 14 antibiotics. L. salivarius LAB9, W. confusa LAB10 and L. mucosae LAB12 were viable in pH 2 for 4 h (mLBS), indicating tolerance to acidity and thus the potential to survive in gastrointestinal tract of the canine. The LAB8-LAB12 strains showed antimicrobial activity against Micrococcus luteus A1 NCIMB86166. CONCLUSIONS: Thirteen different LAB species were found from the faecal microbiota of the healthy canines. Five acid tolerant and antimicrobially active LAB strains with the capacity to grow to high densities both aerobically and anaerobically were chosen to serve as candidate probiotics. SIGNIFICANCE AND IMPACT OF THE STUDY: The selected LAB strains are among the first host-specific LAB with antimicrobial activity isolated from canines that could serve as potential probiotics for canine use.     

16SrRNA sequencing of Dye decolorizing bacteria isolated from Soil

Dye׳s residues in textile effluents are hazardous for humans and animals health. Such pollutants can be degraded into non-harmful molecules using biological approaches that are considered cheaper and ecologically safer. Isolated 15 bacterial cultures from soil that could be used in biological system were showed decolorization capacity for Acid Green dye (33.9% to 94.0%) using thin layer chromatography and broth culture method. The most promising cultures (AMC3) to decolorize Acid green Dye (94.6%) was re-coded as NSDSUAM for submitting at IMTECH, Chandigarh for sequencing. The 16SrRNA sequencing suggested that it can be a variant of Pseudomonas geniculata (99.85% identical similarity) with difference of 2 base pairs to reference strain Pseudomonas geniculata ATCC 19374(T). Thus present study proposed dye decolorizing efficiency of the isolated strain of Pseudomonas geniculata that was previously unnoticed. The sequence is deposited in NCBI GenBank with the accession number {"type":"entrez-nucleotide","attrs":{"text":"KP238100","term_id":"745856746","term_text":"KP238100"}}KP238100.     

Streptomyces sp. strain isolated from river water has high bisphenol A degradability

AIMS: We report the identification of the bisphenol A (BPA) biodegradability in Streptomyces sp. strain isolated from river water. METHODS AND RESULTS: The water samples spiked with BPA (1 mg l(-1)) and the culture solution of Streptomyces sp. strain were placed at 30 degrees C for 10 days and were analysed by high-performance liquid chromatography. A half-life for BPA degradation was between 3 and 4 days. The removal rate of BPA was >90% for 10 days. CONCLUSIONS: These results show that the Streptomyces sp. strain isolated from river water has high BPA degradability. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report of BPA degradation by Streptomyces sp. strain.