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Diversity, activity, and abundance of sulfate-reducing bacteria in saline and hypersaline soda lakes
Foti M Sorokin DY Lomans B Mussman M Zacharova EE Pimenov NV Kuenen JG Muyzer G 《Applied and environmental microbiology》2007,73(7):2093-2100
Soda lakes are naturally occurring highly alkaline and saline environments. Although the sulfur cycle is one of the most active element cycles in these lakes, little is known about the sulfate-reducing bacteria (SRB). In this study we investigated the diversity, activity, and abundance of SRB in sediment samples and enrichment cultures from a range of (hyper)saline soda lakes of the Kulunda Steppe in southeastern Siberia in Russia. For this purpose, a polyphasic approach was used, including denaturing gradient gel electrophoresis of dsr gene fragments, sulfate reduction rate measurements, serial dilutions, and quantitative real-time PCR (qPCR). Comparative sequence analysis revealed the presence of several novel clusters of SRB, mostly affiliated with members of the order Desulfovibrionales and family Desulfobacteraceae. We detected sulfate reducers and observed substantial sulfate reducing rates (between 12 and 423 micromol/dm(3) day(-1)) for most lakes, even at a salinity of 475 g/liter. Enrichments were obtained at salt saturating conditions (4 M Na(+)), using H(2) or volatile fatty acids as electron donors, and an extremely halophilic SRB, strain ASO3-1, was isolated. Furthermore, a high dsr gene copy number of 10(8) cells per ml was detected in a hypersaline lake by qPCR. Our results indicate the presence of diverse and active SRB communities in these extreme ecosystems. 相似文献
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Bachar A Polerecky L Fischer JP Vamvakopoulos K de Beer D Jonkers HM 《FEMS microbiology ecology》2008,65(3):434-448
Pigment analysis in an intact hypersaline microbial mat by hyperspectral imaging revealed very patchy and spatially uncorrelated distributions of photopigments Chl a and BChl a/c, which are characteristic photopigments for oxygenic (diatoms and cyanobacteria) and anoxygenic phototrophs (Chloroflexaceae). This finding is in contrast to the expectation that these biomarker pigments should be spatially correlated, as oxygenic phototrophs are thought to supply the Chloroflexaceae members with organic substrates for growth. We suggest that the heterogeneous occurrence is possibly due to sulfide, whose production by sulfate-reducing bacteria may be spatially heterogeneous in the partially oxic photic zone of the mat. We furthermore mapped the near-infra-red-light controlled respiration of Chloroflexaceae under light and dark conditions and found that Chloroflexaceae are responsible for a major part of oxygen consumption at the lower part of the oxic zone in the mat. The presence of Chloroflexaceae was further confirmed by FISH probe and 16S rRNA gene clone library analysis. We assume that species related to the genera Oscillochloris and 'Candidatus Chlorothrix', in contrast to those related to Chloroflexus and Roseiflexus, depend less on excreted photosynthates but more on the presence of free sulfide, which may explain their presence in deeper parts of the mat. 相似文献
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The diversity and function of aerobic heterotrophic bacteria (AHB) in cyanobacterial mats have been largely overlooked. We used culture-dependent and molecular techniques to explore the species diversity, degradative capacities and functional guilds of AHB in the photic layer (2mm) of an oil-polluted microbial mat from Saudi Arabia. Enrichment isolation was carried out at different salinities (5% and 12%) and temperatures (28 and 45 degrees C) and on various substrates (acetate, glycolate, Spirulina extract and crude oils). Counts of most probable number showed a numerical abundance of AHB in the range of 1.15-8.13x10(6) cellsg(-1) and suggested the presence of halotolerant and thermotolerant populations. Most of the 16S rRNA sequences of the obtained clones and isolates were phylogenetically affiliated to the groups Gammaproteobacteria, Bacteriodetes and Alphaproteobacteria. Groups like Deltaproteobacteria, Verrucomicrobia, Planctomycetes, Spirochaetes, Acidobacteria and Deinococcus-Thermus were only detected by cloning. The strains isolated on acetate and glycolate belonged to the genera Marinobacter, Halomonas, Roseobacter and Rhodobacter whereas the strains enriched on crude oil belonged to Marinobacter and Alcanivorax. Members of the Bacteriodetes group were only enriched on Spirulina extract indicating their specialization in the degradation of cyanobacterial dead cells. The substrate spectra of representative strains showed the ability of all AHB to metabolize cyanobacterial photosynthetic and fermentation products. However, the unique in situ conditions of the mat apparently favored the enrichment of versatile strains that grew on both the cyanobacterial exudates and the hydrocarbons. We conclude that AHB in cyanobacterial mats represent a diverse community that plays an important role in carbon-cycling within microbial mats. 相似文献
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Ghozlan H Deif H Kandil RA Sabry S 《The Journal of General and Applied Microbiology》2006,52(2):63-72
Screening bacteria from different saline environments in Alexandria. Egypt, lead to the isolation of 76 Gram-negative and 14 Gram-positive moderately halophilic bacteria. The isolates were characterized taxonomically for a total of 155 features. These results were analyzed by numerical techniques using simple matching coefficient (SSM) and the clustering was achieved by the unweighed pair-group method of association (UPGMA). At 75% similarity level the Gram-negative bacteria were clustered in 7 phena in addition to one single isolate, whereas 4 phena represented the Gram-positive. Based on phenotypic characteristics, it is suggested that the Gram-negative bacteria belong to the genera Pseudoalteromonas, Flavobacterium, Chromohalobacter, Halomonas and Salegentibacter, in addition to the non-identified single isolate. The Gram-positive bacteria are proposed to belong to the genera Halobacillus, Salinicoccus, Staphylococcus and Tetragenococcus. This study provides the first publication on the biodiversity of moderately halophilic bacteria in saline environments in Alexandria, Egypt. 相似文献
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E. Quesada A. Ventosa F. Rodriguez-Valera A. Ramos-Cormenzana 《Journal of applied microbiology》1982,53(2):155-161
Five rhizosphere soil samples from the dominant xerophytic plants, and nearby root-free soil samples were obtained from a series of hypersaline soils (5.0–10.7% NaCl) from sites near Alicante in Spain. Physico-chemical analyses were made, and the bacterial flora estimated using three different plating media. Counts from rhizosphere soil were always significantly higher than those from root-free soils. A total of 211 strains isolated were purified and identified to genus level; 12 could not be classified. The range of salt concentration allowing growth was determined for each isolate, but this did not correlate with the salt content of the soil habitat. Most isolates appeared to be typical moderate halophiles (with optimum growth between 5 and 15% salts), but about half of them grew on normal media with only 0.9% naCl, a notable difference from moderately halophilic aquatic bacteria. Extreme halophiles were rare but this may have been due to an insufficient incubation period. 相似文献
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V. N. Khmelenina V. N. Shchukin A. S. Reshetnikov I. I. Mustakhimov N. E. Suzina B. Ts. Eshinimaev Yu. A. Trotsenko 《Microbiology》2010,79(4):472-482
Ten strains of aerobic methanotrophic bacteria represented by halophilic neutrophiles or halotolerant alkaliphiles were isolated
from saline and alkaline lakes of southeast Siberia, Mongolia, Africa, and North America. Based on analysis of the nucleotide
sequences of 16S rRNA gene and the pmoA gene encoding particulate methane monooxygenase, the isolates were classified as Methylomicrobium alcaliphilum, Methylomicrobium buryatense, and Methylobacter marinus. All strains of the genus Methylomicrobium were shown to synthesize glycoprotein S-layers located on the cell surface with hexagonal symmetry (p6) as a monolayer of cup-shaped structures or fine “inverted” conical structures and as plates consisting of protein subunits
with inclined (p2) symmetry. During adaptation to the high salinity of the medium, isolated methanotrophs synthesize osmoprotectants: ectoine,
sucrose, and glutamate. The ectC gene encoding ectoine synthase (EctC) was identified in six methanotrophic strains. Phylogenetic analysis of translated amino
acid sequence of the ectC gene fragment suggests lateral transfer of the genes of ectoine synthesis as the most probable way for methanotrophs to acquire
resistance to high external salinity. 相似文献
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Diversity and distribution in hypersaline microbial mats of bacteria related to Chloroflexus spp 总被引:2,自引:0,他引:2
Nübel U Bateson MM Madigan MT Kühl M Ward DM 《Applied and environmental microbiology》2001,67(9):4365-4371
Filamentous bacteria containing bacteriochlorophylls c and a were enriched from hypersaline microbial mats. Based on phylogenetic analyses of 16S rRNA gene sequences, these organisms form a previously undescribed lineage distantly related to Chloroflexus spp. We developed and tested a set of PCR primers for the specific amplification of 16S rRNA genes from filamentous phototrophic bacteria within the kingdom of "green nonsulfur bacteria." PCR products recovered from microbial mats in a saltern in Guerrero Negro, Mexico, were subjected to cloning or denaturing gradient gel electrophoresis and then sequenced. We found evidence of a high diversity of bacteria related to Chloroflexus which exhibit different distributions along a gradient of salinity from 5.5 to 16%. 相似文献
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The role of anti-lactoferrin activity (ALfA) of bacteria in the persistence phenomenon, i.e. long survival of a causative agent in a host body, was studied in experimental staphylococcal infection. In experimental animals infected with isogenic clones of Staphylococcus aureus with different level of ALfA, longer terms were noted in bacterial recovery of staphylococci with this ability. Analysis on the occurrence and level of ALfA in clinical isolates of bacteria, isolated from different forms of infectious process, confirmed the significance of this sign in the persistence of a causative agent. High values of penetrance and expression of ALfA in bacteria were revealed in strains of microorganisms, isolated from chronic inflammatory diseases and from bacterial carriers. 相似文献
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Lay CY Mykytczuk NC Niederberger TD Martineau C Greer CW Whyte LG 《Extremophiles : life under extreme conditions》2012,16(2):177-191
Lost Hammer (LH) spring is a unique hypersaline, subzero, perennial high Arctic spring arising through thick permafrost. In
the present study, the microbial and geochemical characteristics of the LH outflow channels, which remain unfrozen at ≥−18°C
and are more aerobic/less reducing than the spring source were examined and compared to the previously characterized spring
source environment. LH channel sediments contained greater microbial biomass (~100-fold) and greater microbial diversity reflected
by the 16S rRNA clone libraries. Phylotypes related to methanogenesis, methanotrophy, sulfur reduction and oxidation were
detected in the bacterial clone libraries while the archaeal community was dominated by phylotypes most closely related to
THE ammonia-oxidizing Thaumarchaeota. The cumulative percent recovery of 14C-acetate mineralization in channel sediment microcosms exceeded ~30% and ~10% at 5 and −5°C, respectively, but sharply decreased
at −10°C (≤1%). Most bacterial isolates (Marinobacter, Planococcus, and Nesterenkonia spp.) were psychrotrophic, halotolerant, and capable of growth at −5°C. Overall, the hypersaline, subzero LH spring channel
has higher microbial diversity and activity than the source, and supports a variety of niches reflecting the more dynamic
and heterogeneous channel environment. 相似文献
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I. V. Rybakova 《Inland Water Biology》2010,3(4):307-312
The results of studies on the production-destruction processes in the water of overgrowths and periphyton of higher aquatic
plants in the Volzhskii Reach of the Rybinsk Reservoir are presented. The studied aspects included the level of quantitative
development and the activity of bacterioplankton of various ecological groups of macrophytes. It was revealed that the processes
of destruction of organic matter under the impact of bacteria in the macrophyte periphyton prevail over the rate of primary
production in algal periphyton. The production of periphyton and planktic bacteria per 1 m2 of macrophyte overgrowth is calculated. 相似文献
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Anaerobic bacteria and anoxic sediments from soda lakes produced electricity in microbial fuel cells (MFCs). No electricity
was generated in the absence of bacterial metabolism. Arsenate respiring bacteria isolated from moderately hypersaline Mono
Lake (Bacillus selenitireducens), and salt-saturated Searles Lake, CA (strain SLAS-1) oxidized lactate using arsenate as the electron acceptor. However,
these cultures grew equally well without added arsenate using the MFC anode as their electron acceptor, and in the process
oxidized lactate more efficiently. The decrease in electricity generation by consumption of added alternative electron acceptors
(i.e. arsenate) which competed with the anode for available electrons proved to be a useful indicator of microbial activity
and hence life in the fuel cells. Shaken sediment slurries from these two lakes also generated electricity, with or without
added lactate. Hydrogen added to sediment slurries was consumed but did not stimulate electricity production. Finally, electricity
was generated in statically incubated “intact” sediment cores from these lakes. More power was produced in sediment from Mono
Lake than from Searles Lake, however microbial fuel cells could detect low levels of metabolism operating under moderate and
extreme conditions of salt stress. 相似文献
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Epiphytic bacteria biodiversity in Brazilian Cerrado fruit and their cellulolytic activity potential
Dias Mariana da Cruz Pedrozo Miguel Maria Gabriela Duarte Whasley Ferreira Silva Cristina Ferreira Schwan Rosane Freitas 《Annals of microbiology》2015,65(2):851-864
The Cerrado is the second largest Brazilian biome, yet little is known about its wild fauna, flora and microbiota. This work aimed to identify epiphytic bacteria present in fruits native to three different regions of the Cerrado and to select cellulase-producing bacteria. Culture-dependent and culture-independent (PCR-DGGE) methods were used to characterize the microbiota from 32 native Cerrado fruits, and the selection of cellulase-producing bacteria was performed by a semi-quantitative test on carboxymethylcellulose agar medium. Analysis of the 16S rRNA gene sequences of 69 profile representatives showed that the isolates belonged to 29 bacterial genera (Arthrobacter, Bacillus, Paenibacillus, Pseudomonas, Serratia, Staphylococcus, Streptomyces, Enterobacter, Microbacterium, Aerococcus, Bradyrhizobium, Methylobacterium, Erwinia, Pantoea, Acidithiobacillus, Ochrobactrum, Stenotrophomonas, Curtobacterium, Clostridium, Lactobacillus, Xanthomonas, Delftia, Klebsiella, Enterococcus, Burkholderia, Escherichia, Streptococcus, Citrobacter and Achromobacter). Species in the genera Methylobacterium, Stenotrophomonas, Clostridium, Pantoea and Enterobacter were detected by both culture-dependent and culture-independent methods. The species Lactobacillus fermentum, Acinetobacter sp. and Methylomonas methanica were detected only by PCR-DGGE. Additionally, 30 % (178 isolates) of the bacteria tested were able to produce cellulase. The best producers belonged to the genera Bacillus, Streptomyces, Paenibacillus, Enterobacter and Burkholderia, indicating that this ecosystem could be an attractive source for the study of novel enzymes. 相似文献
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Larock PA Lauer RD Schwarz JR Watanabe KK Wiesenburg DA 《Applied and environmental microbiology》1979,38(3):466-470
The evaluation of an improved wipe-rinse technique for the bioassay of large areas was undertaken due to inherent inadequacies in the cotton swab-rinse technique to which assay of spacecraft is currently restricted. Four types of contamination control cloths were initially tested. A polyester-bonded cloth (PBC) was selected for further evaluation because of its superior efficiency and handling characteristics. Results from comparative tests with PBC and cotton swabs on simulated spacecraft surfaces indicated a significantly higher recovery efficiency for the PBC than for the cotton (90.4 versus 75.2%). Of the sampling areas sites studied, PBC was found to be most effective on surface areas not exceeding 0.74 m2 (8.0 feet 2). 相似文献
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Hamid Babavalian Mohammad Ali Amoozegar Ahmad Ali Pourbabaee Mehrdad Moosazadeh Moghaddam Fatemeh Shakeri 《Microbiology》2013,82(4):466-474
Iran has many hypersaline environments, both the permanent and seasonal ones. One of the seasonal hypersaline lakes in the central desert zone is Aran-Bidgol Lake in which microbial diversity has not been characterized, thus the potential usage of this microbial community in biotechnology remained unknown. In this study, screening the halophilic hydrolytic enzyme-producing bacteria from different areas of this lake led to isolation of 61 gram-positive and 22 gram-negative moderately halophilic bacteria. These bacterial isolates were shown to produce a wide variety of hydrolytic enzymes including DNase, inulinase, amylase, lipase, pectinase, protease, chitinase, pullulanase, cellulase, and xylanase. The most common enzymes were DNase and inulinase in gram-positive bacteria, lipase in gram-negative bacteria, and pullulanase and cellulase in gram-positive cocci. Interestingly, combined hydrolytic activates were observed in some isolates. According to their phenotypic characteristics and comparative partial 16S rRNA sequence analysis, the moderately halophilic strains belonged to the genera Halobacillus, Thalassobacillus, Bacillus, Salinicoccus, Idiomarina, Salicola, and Halomonas. 相似文献
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Nitrite reductase activity of sulphate-reducing bacteria prevents their inhibition by nitrate-reducing,sulphide-oxidizing bacteria 总被引:6,自引:0,他引:6
Sulphate-reducing bacteria (SRB) can be inhibited by nitrate-reducing, sulphide-oxidizing bacteria (NR-SOB), despite the fact that these two groups are interdependent in many anaerobic environments. Practical applications of this inhibition include the reduction of sulphide concentrations in oil fields by nitrate injection. The NR-SOB Thiomicrospira sp. strain CVO was found to oxidize up to 15 mM sulphide, considerably more than three other NR-SOB strains that were tested. Sulphide oxidation increased the environmental redox potential (Eh) from -400 to +100 mV and gave 0.6 nitrite per nitrate reduced. Within the genus Desulfovibrio, strains Lac3 and Lac6 were inhibited by strain CVO and nitrate for the duration of the experiment, whereas inhibition of strains Lac15 and D. vulgaris Hildenborough was transient. The latter had very high nitrite reductase (Nrf) activity. Southern blotting with D. vulgaris nrf genes as a probe indicated the absence of homologous nrf genes from strains Lac3 and Lac6 and their presence in strain Lac15. With respect to SRB from other genera, inhibition of the known nitrite reducer Desulfobulbus propionicus by strain CVO and nitrate was transient, whereas inhibition of Desulfobacterium autotrophicum and Desulfobacter postgatei was long-lasting. The results indicate that inhibition of SRB by NR-SOB is caused by nitrite production. Nrf-containing SRB can overcome this inhibition by further reducing nitrite to ammonia, preventing a stalling of the favourable metabolic interactions between these two bacterial groups. Nrf, which is widely distributed in SRB, can thus be regarded as a resistance factor that prevents the inhibition of dissimilatory sulphate reduction by nitrite. 相似文献
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《Harmful algae》2019
The ability of cyanobacteria to produce toxins and other secondary metabolites is patchily distributed in natural populations, enabling the use of cellular oligopeptide compositions as markers to classify strains into ecologically-relevant chemotypical subpopulations. The composition and spatiotemporal distribution of Microcystis chemotypes within and among waterbodies was studied at different time scales by analyzing (i) Microcystis strains isolated between 1998 and 2007 from different Spanish reservoirs and (ii) individual Microcystis aeruginosa colonies collected from pelagic and littoral habitats in Valmayor reservoir (Spain) during a bloom. No agreement between chemotypes and both morphotypes and genotypes (based on cpcBA-IGS, 16S–23S rRNA ITS and mcyB genes) was found, suggesting that oligopeptide profiles in individual strains evolve independently across morphospecies and phylogenetic genotypes, and that the diversity of microcystin variants produced cannot be explained by mcyB gene variations alone. The presence of identical chemotypes in spatially-distant reservoirs with dissimilar trophic state, lithology or depth indicate that waterbody characteristics and geographical boundaries weakly affect chemotype composition and distribution. At smaller spatiotemporal scales (i.e. during bloom), M. aeruginosa populations showed high number of chemotypes, as well as marked differences in chemotype composition and relative abundance among the littoral and pelagic habitats. This indicates that the factors influencing chemotype composition, relative abundance and dynamics operate at short spatial and temporal scales, and supports emerging hypotheses about interactions with antagonistic microorganisms as possible drivers for widespread chemical polymorphisms in cyanobacteria. 相似文献
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