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1.
Joshi AA Kanekar PP Kelkar AS Shouche YS Vani AA Borgave SB Sarnaik SS 《Microbial ecology》2008,55(2):163-172
Aerobic, alkaliphilic bacteria were isolated and characterized from water and sediment samples collected in the winter season,
January 2002 from alkaline Lonar lake, India, having pH 10.5. The total number of microorganisms in the sediment and water
samples was found to be 102–106 cfu g−1 and 102–104 cfu ml−1, respectively. One hundred and ninety-six strains were isolated using different enrichment media. To study the bacterial
diversity of Lonar lake and to select the bacterial strains for further characterization, screening was done on the basis
of pH and salt tolerance of the isolates. Sixty-four isolates were subjected to phenotypic, biochemical characterization and
16S rRNA sequencing. Out of 64, 31 bacterial isolates were selected on the basis of their enzyme profile and further subjected
to phylogenetic analysis. Phylogenetic analysis indicated that most of the Lonar lake isolates were related to the phylum
Firmicutes, containing Low G+C, Gram-positive bacteria, with different genera: Bacillus, Paenibacillus, Alkalibacillus, Exiguobacterium, Planococcus, Enterococcus and Vagococcus. Seven strains constituted a Gram-negative bacterial group, with different genera: Halomonas, Stenotrophomonas and Providencia affiliated to γ-Proteobacteria, Alcaligenes to β-Proteobacteria and Paracoccus to α-Proteobacteria. Only five isolates were High G+C, Gram-positive bacteria associated with phylum Actinobacteria, with
various genera: Cellulosimicrobium, Dietzia, Arthrobacter and Micrococcus. Despite the alkaline pH of the Lonar lake, most of the strains were alkalitolerant and only two strains were obligate alkaliphilic.
Most of the isolates produced biotechnologically important enzymes at alkaline pH, while only two isolates (ARI 351 and ARI
341) showed the presence of polyhydroxyalkcanoate (PHA) and exopolysaccharide (EPS), respectively. 相似文献
2.
Phylogenetic and Physiological Diversity of Bacteria Isolated from Puruogangri Ice Core 总被引:2,自引:0,他引:2
The microbial abundance, the percentage of viable bacteria, and the diversity of bacterial isolates from different regions
of a 83.45-m ice core from the Puruogangri glacier on the Tibetan Plateau (China) have been investigated. Small subunit 16S
rRNA sequences and phylogenetic relationships have been studied for 108 bacterial isolates recovered under aerobic growth
conditions from different regions of the ice core. The genomic fingerprints based on ERIC (enterobacterial repetitive intergenic
consensus)-polymerase chain reaction and physiological heterogeneity of the closely evolutionary related bacterial strains
isolated from different ice core depths were analyzed as well. The results showed that the total microbial cell, percentages
of live cells, and the bacterial CFU ranged from 104 to 105 cell ml−1 (Mean, 9.47 × 104; SD, 5.7 × 104, n = 20), 25–81%, and 0–760 cfu ml−1, respectively. The majority of the isolates had 16S rRNA sequences similar to previously determined sequences, ranging from
92 to 99% identical to database sequences. Based on their 16S rRNA sequences, 42.6% of the isolates were high-G + C-content
(HGC) gram-positive bacteria, 35.2% were low-G + C (LGC) gram-positive bacteria, 16.6% were Proteobacteria, and 5.6% were CFB group. There were clear differences in the depth distribution of the bacterial isolates. The isolates
tested exhibited unique phenotypic properties and high genetic heterogeneity, which showed no clear correlation with depths
of bacterial isolation. This layered distribution and high heterogeneity of bacterial isolates presumably reflect the diverse
bacterial sources and the differences in bacteria inhabiting the glacier’s surface under different past climate conditions. 相似文献
3.
Djedidi S Yokoyama T Tomooka N Ohkama-Ohtsu N Risal CP Abdelly C Sekimoto H 《Systematic and applied microbiology》2011,34(6):453-461
Twenty five rhizobial isolates were obtained from root nodules of Medicago sativa inoculated with soil samples collected from the Sapporo region and Ishigaki Island in Japan. To study their diversity and characterize them in relation to the climatic conditions of their soils of origin, a polyphasic approach analyzing stress tolerance, symbiotic and genetic properties was used. Stress tolerance assays revealed marked variations in salinity, pH and temperature tolerance. Isolates originating from a sub-tropical climate in alkaline soil (Ishigaki Island) tolerated high temperature, salinity and pH levels. Moreover, isolates recovered from a temperate climate in acidic soil (Sapporo) were sensitive to high temperature and salinity, and tolerated acidic pH. Phylogenetic analysis of conserved 16S rRNA and recA genes, and symbiotic nodA and nifDK revealed 25 isolates to be closely related to Ensifer meliloti. Furthermore, the branch patterns of phylogenetic trees constructed from different genes revealed the existence of at least two E. meliloti types in the soils studied. These results may be relevant to programs directed towards improving crop productivity through biofertilization with locally adapted and genetically defined strains. 相似文献
4.
The influence of ammonia on the anaerobic degradation of peptone by mesophilic and thermophilic populations of biowaste was
investigated. For peptone concentrations from 5 g l−1 to 20 g l−1 the mesophilic population revealed a higher rate of deamination than the thermophilic population, e.g. 552 mg l−1 day−1 compared to 320 mg l−1 day−1 at 10 g l−1 peptone. The final degree of deamination of the thermophilic population was, however, higher: 102 compared to 87 mg NH3/g peptone in the mesophilic cultures. If 0.5–6.5 g l−1 ammonia was added to the mesophilic biowaste cultures, deamination of peptone, degradation of its chemical oxygen demand
(COD) and formation of biogas were increasingly inhibited, but no hydrogen was formed. The thermophilic biowaste cultures
were most active if around 1 g ammonia l−1 was present. Deamination, COD degradation and biogas production decreased at lower and higher ammonia concentrations and
hydrogen was formed in addition to methane. Studies of the inhibition by ammonia of peptone deamination, COD degradation and
methane formation revealed a K
i (50%) for NH3 of 92, 95 and 88 mg l−1 at 37 °C and 251, 274 and 297 mg l−1 at 55 °C respectively. This indicated that the thermophilic flora tolerated significantly more NH3 than the mesophilic flora. In the mesophilic reactor effluent 4.6 × 108 peptone-degrading colony-forming units (cfu)/ml were culturable, whereas in the thermophilic reactor effluent growth of only
5.6 × 107 cfu/ml was observed.
Received: 24 April 1998 / Received revision: 26 June 1998 / Accepted: 27 June 1998 相似文献
5.
T. N. R. Srinivas S. S. S. Nageswara Rao P. Vishnu Vardhan Reddy M. S. Pratibha B. Sailaja B. Kavya K. Hara Kishore Z. Begum S. M. Singh S. Shivaji 《Current microbiology》2009,59(5):537-547
Culturable bacterial diversity of seven marine sediment samples of Kongsfjorden and a sediment and a soil sample from Ny-Ålesund, Svalbard, Arctic was studied. The bacterial abundance in the marine sediments of Kongsfjorden varied marginally (0.5 × 103–1.3 × 104 cfu/g sediment) and the bacterial number in the two samples collected from the shore of Ny-Ålesund also was very similar (0.6 × 104 and 3.4 × 104, respectively). From the nine samples a total of 103 bacterial isolates were obtained and these isolates could be grouped in to 47 phylotypes based on the 16S rRNA gene sequence belonging to 4 phyla namely Actinobacteria, Bacilli, Bacteroidetes and Proteobacteria. Representatives of the 47 phylotypes varied in their growth temperature range (4–37°C), in their tolerance to NaCl (0.3–2 M NaCl) and growth pH range (2–11). Representatives of 26 phylotypes exhibited amylase and lipase activity either at 5 or 20°C or at both the temperatures. A few of the representatives exhibited amylase and/or lipase activity only at 5°C. None of the phylotypes exhibited protease activity. Most of the phylotypes (38) were pigmented. Fatty acid profile studies indicated that short chain fatty acids, unsaturated fatty acids, branched fatty acids, the cyclic and the cis fatty acids are predominant in the psychrophilic bacteria. 相似文献
6.
Enrichment-based methods targeted at uranium-tolerant populations among the culturable, aerobic, chemo-heterotrophic bacteria
from the subsurface soils of Domiasiat (India’s largest sandstone-type uranium deposits, containing an average ore grade of
0.1 % U3O8), indicated a wide occurrence of Serratia marcescens. Five representative S. marcescens isolates were characterized by a polyphasic taxonomic approach. The phylogenetic analyses of 16S rRNA gene sequences showed
their relatedness to S. marcescens ATCC 13880 (≥99.4% similarity). Biochemical characteristics and random amplified polymorphic DNA profiles revealed significant
differences among the representative isolates and the type strain as well. The minimum inhibitory concentration for uranium
U(VI) exhibited by these natural isolates was found to range from 3.5–4.0 mM. On evaluation for their uranyl adsorption properties,
it was found that all these isolates were able to remove nearly 90–92% (21–22 mg/L) and 60–70% (285–335 mg/L) of U(VI) on
being challenged with 100 μM (23.8 mg/L) and 2 mM (476 mg/L) uranyl nitrate solutions, respectively, at pH 3.5 within 10 min
of exposure. his capacity was retained by the isolates even after 24 h of incubation. Viability tests confirmed the tolerance
of these isolates to toxic concentrations of soluble uranium U(VI) at pH 3.5. This is among the first studies to report uranium-tolerant
aerobic chemoheterotrophs obtained from the pristine uranium ore-bearing site of Domiasiat. 相似文献
7.
In 12 selected flats in Sosnowiec, Upper Silesia, the concentrations of particulate aerosol, bioaerosol and bacterial endotoxin
were examined. Concentrations of particulate aerosol, bacteria, fungi and endotoxin were in the order of 101–102
μg/m3, 101–103 cfu/m3, 100–102 cfu/m3 and 10−2–10−1 ng/m3, respectively. The most numerous group of microorganisms in indoor air during the winter season were Gram positive mesophilic
bacteria. They were more common in flats polluted with tobacco smoke. The concentrations of airborne endotoxins were higher
in flats polluted with tobacco smoke in all size ranges. The highest level of endotoxins was found in the fraction of fine
particles below 5μm. 相似文献
8.
Cultivation and Growth Characteristics of a Diverse Group of Oligotrophic Marine Gammaproteobacteria 总被引:10,自引:2,他引:8
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Forty-four novel strains of Gammaproteobacteria were cultivated from coastal and pelagic regions of the Pacific Ocean using high-throughput culturing methods that rely on dilution to extinction in very low nutrient media. Phylogenetic analysis showed that the isolates fell into five rRNA clades, all of which contained rRNA gene sequences reported previously from seawater environmental gene clone libraries (SAR92, OM60, OM182, BD1-7, and KI89A). Bootstrap analyses of phylogenetic reliability did not support collapsing these five clades into a single clade, and they were therefore named the oligotrophic marine Gammaproteobacteria (OMG) group. Twelve cultures chosen to represent the five clades were successively purified in liquid culture, and their growth characteristics were determined at different temperatures and dissolved organic carbon concentrations. The isolates in the OMG group were physiologically diverse heterotrophs, and their physiological properties generally followed their phylogenetic relationships. None of the isolates in the OMG group formed colonies on low- or high-nutrient agar upon their first isolation from seawater, while 7 of 12 isolates that were propagated for laboratory testing eventually produced colonies on 1/10 R2A agar. The isolates grew relatively slowly in natural seawater media (1.23 to 2.63 day−1), and none of them grew in high-nutrient media (>351 mg of C liter−1). The isolates were psychro- to mesophilic and obligately oligotrophic; many of them were of ultramicrobial size (<0.1 μm3). This cultivation study revealed that sporadically detected Gammaproteobacteria gene clones from seawater are part of a phylogenetically diverse constellation of organisms mainly composed of oligotrophic and ultramicrobial lineages that are culturable under specific cultivation conditions. 相似文献
9.
Freeman SA Sierra-Alvarez R Altinbas M Hollingsworth J Stams AJ Smidt H 《Biodegradation》2008,19(2):161-177
The microbial communities established in mesophilic and thermophilic expanded granular sludge bed reactors operated with sulfate
as the electron acceptor were analyzed using 16S rRNA targeted molecular methods, including denaturing gradient gel electrophoresis,
cloning, and phylogenetic analysis. Bacterial and archaeal communities were examined over 450 days of operation treating ethanol
(thermophilic reactor) or ethanol and later a simulated semiconductor manufacturing wastewater containing citrate, isopropanol,
and polyethylene glycol 300 (mesophilic reactor), with and without the addition of copper(II). Analysis, of PCR-amplified
16S rRNA gene fragments using denaturing gradient gel electrophoresis revealed a defined shift in microbial diversity in both
reactors following a change in substrate composition (mesophilic reactor) and in temperature of operation from 30°C to 55°C
(thermophilic reactor). The addition of copper(II) to the influent of both reactors did not noticeably affect the composition
of the bacterial or archaeal communities, which is in agreement with the very low soluble copper concentrations (3–310 μg l−1) present in the reactor contents as a consequence of extensive precipitation of copper with biogenic sulfides. Furthermore,
clone library analysis confirmed the phylogenetic diversity of sulfate-reducing consortia in mesophilic and thermophilic sulfidogenic
reactors operated with simple substrates. 相似文献
10.
Katharina Porsch Balázs Wirth Erika M Tóth Florian Schattenberg Marcell Nikolausz 《Microbial biotechnology》2015,8(5):801-814
Alkaline pretreatment has the potential to enhance the anaerobic digestion of lignocellulosic biomass to biogas. However, the elevated pH of the substrate may require alkalitolerant microbial communities for an effective digestion. Three mixed anaerobic lignocellulolytic cultures were enriched from sediments from two soda lakes with wheat straw as substrate under alkaline (pH 9) mesophilic (37°C) and thermophilic (55°C) conditions. The gas production of the three cultures ceased after 4 to 5 weeks, and the produced gas was composed of carbon dioxide and methane. The main liquid intermediates were acetate and propionate. The physiological behavior of the cultures was stable even after several transfers. The enrichment process was also followed by molecular fingerprinting (terminal restriction fragment length polymorphism) of the bacterial 16S rRNA gene and of the mcrA/mrtA functional gene for methanogens. The main shift in the microbial community composition occurred between the sediment samples and the first enrichment, whereas the structure was stable in the following transfers. The bacterial communities mainly consisted of Sphingobacteriales, Clostridiales and Spirochaeta, but differed at genus level. Methanothermobacter and Methanosarcina genera and the order Methanomicrobiales were predominant methanogenes in the obtained cultures. Additionally, single cellulolytic microorganisms were isolated from enrichment cultures and identified as members of the alkaliphilic or alkalitolerant genera. The results show that anaerobic alkaline habitats harbor diverse microbial communities, which can degrade lignocellulose effectively and are therefore a potential resource for improving anaerobic digestion. 相似文献
11.
Jeon JH Lee HS Kim JT Kim SJ Choi SH Kang SG Lee JH 《Applied microbiology and biotechnology》2012,93(2):623-631
To search for novel lipolytic enzymes, a metagenomic library was constructed from the tidal flat sediment of Ganghwa Island
in South Korea. By functional screening using tributyrin agar plates, 3 clones were selected from among the 80,050 clones
of the fosmid library. The sequence analysis revealed that those clones contained different open reading frames, which showed
50–57% amino acid identity with putative lipolytic enzymes in the database. Based on the phylogenetic analysis, they were
identified to encode novel members, which form a distinct and new subfamily in the family IV of bacterial lipolytic enzymes.
The consensus sequence, GT(S)SA(G)G, encompassing the active site serine of the enzymes was different from the GDSAG motif,
conserved in the other subfamily. The genes were expressed in Escherichia coli and recombinant proteins were purified as active soluble forms. The enzymes showed the highest activity toward p-nitrophenyl valerate (C5) and exhibited optimum activities at mesophilic temperature ranges and slightly alkaline pH. In
particular, the enzymes displayed salt tolerance with over 50% of the maximum activity remained in the presence of 3 M NaCl
(or KCl). In this study, we demonstrated that the metagenomic approach using marine tidal flat sediment as a DNA source expanded
the diversity of lipolytic enzyme-encoding genes. 相似文献
12.
Leta S. Gumaelius L. Assefa F. Dalhammar G. 《World journal of microbiology & biotechnology》2004,20(4):405-411
In order to identify potential microorganisms with high denitrifying capacity from tannery wastewaters, 1000 pure cultures
of bacterial isolates from Modjo Tannery Pilot and Ethio-tannery wastewater treatment plants (WWTP), in Ethiopia, were investigated.
Twenty-eight isolates were selected as efficient denitrifiers. These were Gram-negative rods, oxidase and catalase positive
denitrifying organisms. The 28 denitrifying strains were further classified according to their biochemical fingerprints into
three different phylogenetic groups (BPT1, BPT2 and BPT3) and seven singles. Isolates B79T, B11, B12, B15, B28 and B38 belonging to the BPT3 cluster were found to be the most efficient denitrifying bacteria. All
phenotypic studies, including cellular fatty acid profiles, showed that the 6 BPT3 isolates were closely related to each other.
The 16S rRNA partial sequence analysis of type strain B79T(CCUG 45880) indicated a sequence similarity of 99% to Brachymonas denitrificans JCM9216 (D14320) in the β-subdivision of proteobacteria. Further studies of the effects of chromium III and sulphide on the six Brachymonas denitrificans strains indicated that denitrification by the isolates were inhibited 50% at concentrations of 54 and 96 mg/l, respectively.
The efficient isolates characterized in this study are of great value because of their excellent denitrifying properties and
relatively high tolerance to the concentrations of toxic compounds (70 mg chromium/l and 160 mg sulphide/l) prevailing in
tannery wastewaters. 相似文献
13.
Navarro JB Moser DP Flores A Ross C Rosen MR Dong H Zhang G Hedlund BP 《Microbial ecology》2009,57(2):307-320
Ephemerally wet playas are conspicuous features of arid landscapes worldwide; however, they have not been well studied as
habitats for microorganisms. We tracked the geochemistry and microbial community in Silver Lake playa, California, over one
flooding/desiccation cycle following the unusually wet winter of 2004–2005. Over the course of the study, total dissolved
solids increased by ∽10-fold and pH increased by nearly one unit. As the lake contracted and temperatures increased over the
summer, a moderately dense planktonic population of ∽1 × 106 cells ml−1 of culturable heterotrophs was replaced by a dense population of more than 1 × 109 cells ml−1, which appears to be the highest concentration of culturable planktonic heterotrophs reported in any natural aquatic ecosystem.
This correlated with a dramatic depletion of nitrate as well as changes in the microbial community, as assessed by small subunit
ribosomal RNA gene sequencing of bacterial isolates and uncultivated clones. Isolates from the early-phase flooded playa were
primarily Actinobacteria, Firmicutes, and Bacteroidetes, yet clone libraries were dominated by Betaproteobacteria and yet
uncultivated Actinobacteria. Isolates from the late-flooded phase ecosystem were predominantly Proteobacteria, particularly
alkalitolerant isolates of Rhodobaca, Porphyrobacter, Hydrogenophaga, Alishwenella, and relatives of Thauera; however, clone libraries were composed almost entirely of Synechococcus (Cyanobacteria). A sample taken after the playa surface was completely desiccated contained diverse culturable Actinobacteria
typically isolated from soils. In total, 205 isolates and 166 clones represented 82 and 44 species-level groups, respectively,
including a wide diversity of Proteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, Gemmatimonadetes, Acidobacteria,
and Cyanobacteria.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
Zucchi TD Bonda AN Frank S Kim BY Kshetrimayum JD Goodfellow M 《Antonie van Leeuwenhoek》2012,102(1):91-98
The status of two mesophilic filamentous actinomycetes isolated from an arid Australian soil sample was determined using a polyphasic taxonomic approach. The isolates had chemical and morphological properties consistent with their classification in the genus Amycolatopsis, assignments that were supported by analysis of 16S rRNA gene sequence data. Isolate SF26T formed a distinct phyletic line and hence was sharply separated from its nearest phylogenetic neighbour, Amycolatopsis sacchari DSM 44468T. In contrast, isolate SF27T formed a subclade in the Amycolatopsis tree with Amycolatopsis vancoresmycina DSM 44592T but was separated readily from the latter by DNA:DNA pairing data. The two isolates were distinguished from one another and from their respective nearest phylogenetic neighbours using a range of phenotypic properties. These data indicate that the two isolates should be recognized as new species in the genus Amycolatopsis. The names proposed for these new taxa are Amycolatopsis bartoniae sp. nov. and Amycolatopsis bullii sp. nov. with isolates SF26T (=NCIMB 14706T = NRRL B-2846T) and SF27T (=NCIMB 14707T = NRRL B-24847T) as the respective type strains. 相似文献
15.
A short coccoid-rod-shaped, nonmotile actinobacteria strain MSL-11T was isolated from soil in Bigeum Island, Korea. A polyphasic study was undertaken to establish the taxonomic position of
this strain. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain MSL-11T forms an evolutionary lineage within the radiation of the genus Nocardioides. The cell wall peptidoglycan of strain MSL-11T contained ll-diaminopimelic acid, indicating wall chemotype I. The predominant menaquinone was MK-8(H4). Strain MSL-11T had a cellular fatty acid profile containing straight-chain, branched, unsaturated, and 10-methyl fatty acids, with iso-C16:0 as a major fatty acid component detected. The DNA G + C content of the strain was 71.8 mol%. Comparative 16S rRNA gene sequencing
revealed that the strains constituted a distinct subclade within the genus Nocardioides, displaying a 16S rRNA gene sequence similarity of about 95.68% with Nocardioides jensenii DSM 20641T. On the basis of both phenotypic and phylogenetic evidence, the strain is separated from previously described Nocardioides species and should be assigned to represent a novel species of the genus Nocardioides, for which the name Nocardioides dilutes sp. nov. is proposed. The type strain is strain MSL-11T (= KCTC 19288T = DSM 19318T). 相似文献
16.
Anaerobic alkalithermophiles, a novel group of extremophiles 总被引:2,自引:0,他引:2
Juergen Wiegel 《Extremophiles : life under extreme conditions》1998,2(3):257-267
Although some anaerobic and aerobic mesophiles have long been known to grow at alkaline pH (above 9.5), little was known
until recently about thermophilic alkaliphiles, termed now alkalithermophiles. This minireview describes presently known and
recently validly described anaerobic alkalithermophilic bacteria (pHopt
55C > 8.5; Topt > 55°C) and alkalitolerant thermophiles (pHopt
55C < 8.5 but pHmax
55C above 9.0). Some of these are widely distributed, but others have been isolated (thus far) only from one specific location.
This novel group of anaerobic bacteria is comprised of physiologically different genera and species which, so far, all belong
to the Gram-type positive Bacillus-Clostridium phylogenetic subbranch. An interesting feature of these anaerobic alkalithermophiles is that most of the isolates have short
doubling times. The fastest growing among them are strains of Thermobrachium celere, with doubling times as short as 10 min while growing above pH 9.0 and above 55°C.
Received: January 22, 1998 / Accepted: February 16, 1998 相似文献
17.
Bacterial diversity in five Icelandic geothermal waters: temperature and sinter growth rate effects 总被引:1,自引:0,他引:1
The microbial ecology associated with siliceous sinters was studied in five geochemically diverse Icelandic geothermal systems.
Bacterial 16S rRNA clone libraries were constructed from water-saturated precipitates from each site resulting in a total
of 342 bacterial clone sequences and 43 species level phylotypes. In near-neutral, saline (2.6–4.7% salinity) geothermal waters
where sinter growth varied between 10 and ~300 kg year−1 m−2, 16S rRNA gene analyses revealed very low (no OTUs could be detected) to medium (9 OTUs) microbial activity. The most dominant
phylotypes found in these waters belong to marine genera of the Proteobacteria. In contrast, in alkaline (pH = 9–10), meteoric geothermal waters with temperature = 66–96°C and <1–20 kg year−1m−2 sinter growth, extensive biofilms (a total of 34 OTUs) were observed within the waters and these were dominated by members
of the class Aquificae (mostly related to Thermocrinis), Deinococci (Thermus species) as well as Proteobacteria. The observed phylogenetic diversity (i.e., number and composition of detected OTUs) is argued to be related to the physico-chemical
regime prevalent in the studied geothermal waters; alkaliphilic thermophilic microbial communities with phylotypes related
to heterotrophic and autotrophic microorganisms developed in alkaline high temperature waters, whereas halophilic mesophilic
communities dominated coastal geothermal waters. 相似文献
18.
Qing-Zhong Peng Jun Chen Yu-Qin Zhang Qi-Hui Chen De-Jiao Peng Xiao-Long Cui Wen-Jun Li Yi-Guang Chen 《Antonie van Leeuwenhoek》2009,96(4):645-652
A Gram-positive, endospore-forming, catalase- and oxidase-positive, motile, rod-shaped, aerobic bacterium, designated strain
JSM 079157T, was isolated from surface seawater off the coastline of Naozhou Island in South China Sea. The organism was able to grow
with 1–15% (w/v) total salts (optimum, 4–7%), and at pH 6.0–10.0 (optimum, pH 7.5) and 10–45°C (optimum, 30°C). meso-Diaminopimelic acid was present in the cell-wall peptidoglycan. The predominant menaquinone was MK-7, and the polar lipids
were diphosphatidylglycerol and phosphatidylglycerol. The major cellular fatty acids were anteiso-C15:0 (45.1%) and anteiso-C17:0 (16.2%), and the DNA G + C content was 39.5 mol%. A phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed
that strain JSM 079157T should be assigned to the genus Virgibacillus, being related most closely to the type strains of Virgibacillus litoralis (97.4% sequence similarity), Virgibacillus necropolis (97.3%) and Virgibacillus carmonensis (97.1%). These four strains formed a distinct subcluster in the phylogenetic tree. The levels of DNA–DNA relatedness between
the new isolate and the type strains of V. litoralis, V. necropolis and V. carmonensis were 30.4, 19.3 and 12.6%, respectively. The results of the phylogenetic analysis, combined with DNA–DNA relatedness data,
phenotypic characteristics and chemotaxonomic information, support the suggestion that strain JSM 079157T represents a new species of the genus Virgibacillus, for which the name Virgibacillus zhanjiangensis sp. nov. is proposed. The type strain is JSM 079157T (=DSM 21084T = KCTC 13227T). 相似文献
19.
Microorganisms play an important role in the geobiocycling of arsenic element. However, little is known about the bacteria
involved in this process in oceanic environments. In this report, arsenite-resistant bacteria were detected in deep-sea sediments
on the Southwest Indian Ridge. From arsenite enriched cultures, 54 isolates were obtained, which showed varied tolerance to
arsenite of 2–80 mM. Phylogenetic analysis based on 16S rRNA showed that they mainly belonged to Proteobacteria and Actinobacteria.
Denaturing gradient gel electrophoresis revealed that Microbacterium esteraromaticum was the dominant member in the arsenite enriched communities, and this was reconfirmed by 16S rRNA gene library analyses.
Thus, M. esteraromaticum showed highest resistant to arsenite among the detected bacteria. These results indicate that there are quite diverse bacteria
of arsenite resistance inhabiting the deep sea sediment, which may play a role in the geobiocycling of arsenic element in
marine environments. 相似文献
20.
The sizes and compositions of bacterial populations found on leaves of greenhouse and field grown tomato plants were studied
by dilution plating, fatty acid methyl ester analysis (FAME), and BIOLOG plates of isolates in pure cultures. In the greenhouse,
overhead-irrigated plants sustained higher microbial populations (up to 105 cfu g−1) than soil-irrigated plants (103 cfu g−1). Strains isolated from overhead-irrigated plants grown in a vegetable garden (n=216) and from greenhouse-grown plants (n=114) were subjected to FAME analysis. Similarly, strains from soil-irrigated field-grown plants (n=83) were identified using BIOLOG plates. In each case, populations were dominated by a few genera. When concentrated phyllosphere
washes (CPW) were sprayed on greenhouse-grown, soil-irrigated plants, leaf bacterial populations of more than 105 CFU g−1 were sustained for 4 days; sterile buffer-sprayed leaves sustained less than 104 CFU g−1. No significant enrichment of any strain isolated from the sprayed leaves could be detected by FAME identification of randomly
selected colonies. However, when recurring leaf saprophytic species (both Gram-positive and Gram-negative) isolated from these
experiments and from plants grown outdoors were tested for epiphytic colonization under stressful conditions, all could still
be detected at various levels up to 4 days after inoculation, indicating differential epiphytic fitness. The non-epiphytic
bacteriaEscherichia coli andAzospirillum brasilense disappeared from the leaf surface within the same experimental period. 相似文献