Halomonas maura is a physiologically versatile bacterium of both ecological and biotechnological interest

Llamas, Inmaculada; Moral, Ana; Martínez‐Checa, Fernando; Arco, Yolanda; Arias, Soledad; Quesada, Emilia

doi:10.1007/s10482-005-9043-9

Cited by 57 publications

(43 citation statements)

References 72 publications

(71 reference statements)

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“…Halomonas maura does not differ from this model, particularly in that EPS is essential to its formation of biofilms (Arco et al, 2005;Llamas et al, 2006). As mentioned above, the GacS/ GacA TCS controls EPS biosynthesis in H. anticariensis, which prompted us to investigate whether this system affects biofilm formation.…”

Section: Discussionmentioning

confidence: 95%

Genetic and phenotypic analysis of the GacS/GacA system in the moderate halophile Halomonas anticariensis

2013

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A multisensory, hybrid histidine kinase (HK) and a response regulator (RR), which together may well constitute a two-component regulatory system (TCS), have been located in Halomonas anticariensis FP35 T by transposon mutagenesis. This TCS is homologous to the GacS/GacA system described for many Gram-negative bacteria. An analysis of crude N-acylhomoserine lactone (AHL) extracts from cultures of FP35gacS and FP35gacA mutants showed that they produced lower quantities of AHLs than the wild-type strain. In addition, RT-PCR analysis revealed a considerable decrease in the expression of the quorum-sensing (QS) genes hanR and hanI compared with the wild-type strain. This result indicates that the GacS/GacA TCS exerts a positive effect upon the QS HanR/HanI system and suggests its integral involvement in the intercellular communication strategies of this bacterium. We have also demonstrated the influence of GacS and GacA upon exopolysaccharide production and biofilm formation, in which this regulatory machinery appears to play a key role in an overall system that co-ordinates gene expression and behaviour in H. anticariensis FP35 T in response to environmental conditions.

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Section: Discussionmentioning

confidence: 95%

Genetic and phenotypic analysis of the GacS/GacA system in the moderate halophile Halomonas anticariensis

2013

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“…are usually associated with aerobic environments and have subsequently been used in several biotransformation studies under aerobic conditions, including the degradation of catechol (Alva and Peyton 2003) and salicylate (Oie et al 2007). However, some Halomonas spp., including H. maura, are capable of anoxic respiration under nitrate reducing conditions (Aragandoña et al 2006;Llamas et al 2006;Peyton et al 2001). Previous studies have utilized Halomonas isolates to study metal-microbe interactions under anoxic conditions (Francis et al 2000;Khijniak et al 2003), although Cr(VI) reduction by a Halomonas isolate has not been reported.…”

Section: Resultsmentioning

confidence: 99%

Fe(III), Cr(VI), and Fe(III) mediated Cr(VI) reduction in alkaline media using a Halomonas isolate from Soap Lake, Washington

et al. 2008

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Hexavalent chromium is one of the most widely distributed environmental contaminants. Given the carcinogenic and mutagenic consequences of Cr(VI) exposure, the release of Cr(VI) into the environment has long been a major concern. While many reports of microbial Cr(VI) reduction are in circulation, very few have demonstrated Cr(VI) reduction under alkaline conditions. Since Cr(VI) exhibits higher mobility in alkaline soils relative to pH neutral soils, and since Cr contamination of alkaline soils is associated with a number of industrial activities, microbial Cr(VI) reduction under alkaline conditions requires attention.Soda lakes are the most stable alkaline environments on earth, and contain a wide diversity of alkaliphilic organisms. In this study, a bacterial isolate belonging to the Halomonas genus was obtained from Soap Lake, a chemically stratified alkaline lake located in central Washington State. The ability of this isolate to reduce Cr(VI) and Fe(III) was assessed under alkaline (pH = 9), anoxic, non-growth conditions with acetate as an electron donor. Metal reduction rates were quantified using Monod kinetics. In addition, Cr(VI) reduction experiments were carried out in the presence of Fe(III) to evaluate the possible enhancement of Cr(VI) reduction rates through electron shuttling mechanisms. While Fe(III) reduction rates were slow compared to previously reported rates, Cr(VI) reduction rates fell within range of previously reported rates.

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“…in the sandstone column environment may be related to the known ability of these organisms to form biofilms (e.g., Klausen et al, 2006; Li et al, 2009) thus giving them a competitive advantage in sessile environments. Halomonas sp., also enriched in the sandstone columns (Table 1), are also known biofilm and exopolysaccharide-forming organisms that may allow for the solubilization of hydrocarbons attached to rock (Llamas et al, 2006; Qurashi and Sabri, 2012; Gutierrez et al, 2013). Members of this genus have also been found to be associated with oil reservoirs and the deep biosphere (Mnif et al, 2009; Dong et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Conversion of crude oil to methane by a microbial consortium enriched from oil reservoir production waters

Berdugo-Clavijo

Gieg

2014

Front. Microbiol.

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The methanogenic biodegradation of crude oil is an important process occurring in petroleum reservoirs and other oil-containing environments such as contaminated aquifers. In this process, syntrophic bacteria degrade hydrocarbon substrates to products such as acetate, and/or H2 and CO2 that are then used by methanogens to produce methane in a thermodynamically dependent manner. We enriched a methanogenic crude oil-degrading consortium from production waters sampled from a low temperature heavy oil reservoir. Alkylsuccinates indicative of fumarate addition to C5 and C6 n-alkanes were identified in the culture (above levels found in controls), corresponding to the detection of an alkyl succinate synthase encoding gene (assA/masA) in the culture. In addition, the enrichment culture was tested for its ability to produce methane from residual oil in a sandstone-packed column system simulating a mature field. Methane production rates of up to 5.8 μmol CH4/g of oil/day were measured in the column system. Amounts of produced methane were in relatively good agreement with hydrocarbon loss showing depletion of more than 50% of saturate and aromatic hydrocarbons. Microbial community analysis revealed that the enrichment culture was dominated by members of the genus Smithella, Methanosaeta, and Methanoculleus. However, a shift in microbial community occurred following incubation of the enrichment in the sandstone columns. Here, Methanobacterium sp. were most abundant, as were bacterial members of the genus Pseudomonas and other known biofilm forming organisms. Our findings show that microorganisms enriched from petroleum reservoir waters can bioconvert crude oil components to methane both planktonically and in sandstone-packed columns as test systems. Further, the results suggest that different organisms may contribute to oil biodegradation within different phases (e.g., planktonic vs. sessile) within a subsurface crude oil reservoir.

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Halomonas maura is a physiologically versatile bacterium of both ecological and biotechnological interest

Cited by 57 publications

References 72 publications

Genetic and phenotypic analysis of the GacS/GacA system in the moderate halophile Halomonas anticariensis

Genetic and phenotypic analysis of the GacS/GacA system in the moderate halophile Halomonas anticariensis

Fe(III), Cr(VI), and Fe(III) mediated Cr(VI) reduction in alkaline media using a Halomonas isolate from Soap Lake, Washington

Conversion of crude oil to methane by a microbial consortium enriched from oil reservoir production waters

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