By admin /

Complete Genome Sequence of Leptospirillum ferrooxidans Strain C, Isolated from a Fresh Volcanic Ash Deposit on the Island of Miyake, Japan. Leptospirillum is a genus of iron-oxidizing bacteria which plays an important role in industrial bioleaching (the conversion of metals to a soluble form) and. The name Leptospirillum ferrooxidans is not in the Approved Lists of Bacterial. Names (), nor has it been subsequently validly published. In accordance.

Author: Shazragore Majar
Country: Maldives
Language: English (Spanish)
Genre: Medical
Published (Last): 15 March 2010
Pages: 16
PDF File Size: 10.57 Mb
ePub File Size: 20.86 Mb
ISBN: 148-6-33160-522-5
Downloads: 94607
Price: Free* [*Free Regsitration Required]
Uploader: Vilabar

Gene function analysis in extremophiles: In Centro de Astrobiologia it has been considered the Tinto river as a model ecosystem to study life based on iron. The final goal is to study the biological and metabolic diversity in microorganisms living there, following a genomic approach, to get insights to the mechanisms of adaptation to this environment.

The Gram-negative bacterium Leptospirillum ferrooxidans is one of the most abundant microorganisms in the river, and it is one of the main responsible in maintenance of pH balance and, as a consequence, the physico-chemical properties of the exosystem.

We have constructed a Shotgun DNA microarrays from this bacterium and we have used it to studied its genetic capacity for nitrogen fixation. With this approach we have identified most of the genes necessary for dinitrogen N2 reduction, confirming the capacity of L. Isolation, sequence analysis, and comparison of two plasmids 28 and 29 kilobases from the biomining bacterium Leptospirillum ferrooxidans ATCC Altogether, a total of 67 open reading frames ORFs were identified on both plasmids, of which 32 had predicted products with high homology to proteins of known function, while 11 ORFs had predicted products with homology to previously identified proteins of unknown function.

An analysis of the ORFs and other features of the two plasmids, the first to be isolated from a bacterium of the genus Leptospirillumis presented. Complete genome sequence of Leptospirillum ferrooxidans strain C, isolated from a fresh volcanic ash deposit on the island of Miyake, Japan.

A diazotrophic, acidophilic, iron-oxidizing bacteriumLeptospirillum ferrooxidansknown to be difficult to cultivate, was isolated from a fresh volcanic ash deposit on the island of Miyake, Japan.

Here, we report the complete genome sequence of a cultured strain, C Complete genome sequence of the bioleaching bacterium Leptospirillum sp. We describe the complete genome sequence of Leptospirillum sp. This work provides data to gain insights about adaptive response of Leptospirillum spp. Dissolution was monitored through analysis of the coexisting aqueous solution using inductively coupled plasma atomic emission spectroscopy and coupled ion chromatography-inductively coupled plasma mass spectrometry, and chemical changes at the mineral surface observed using X-ray photoelectron spectroscopy and environmental scanning electron microscopy ESEM.

Biologically mediated oxidation of arsenopyrite and enargite 2.

The formation of Fe III -oxyhydroxides, ferric sulphate and arsenate was observed for arsenopyrite, thiosulphate and an unknown arsenic oxide for enargite. ESEM revealed an extensive coating of an extracellular polymeric substance associated with the L. Although the relative oxidation rates of enargite were greater in the presence of L. Two arsenic-resistant plasmids were constructed and introduced into Thiobacillus ferrooxidans strains by conjugation.

The plasmids with the replicon of wide-host-range plasmid RSF were stable in T. The arsenic resistance genes originating from the heterotroph were expressed in this obligately autotrophic bacteriumbut the promoter derived from T.

The effect of CO2 availability on the growth, iron oxidation and CO2-fixation rates of pure cultures of Leptospirillum ferriphilum and Acidithiobacillus ferrooxidans.

Understanding how bioleaching systems respond to the availability of CO 2 is lepyospirillum to developing operating conditions that select for optimum microbial performance. Therefore, the fetrooxidans of inlet gas and associated dissolved CO 2 concentration on the growth, feerrooxidans oxidation and CO 2 -fixation rates of pure cultures of Acidithiobacillus ferrooxidans and Leptospirillum ferriphilum was investigated in a batch stirred tank system.

The minimum inlet CO 2 concentrations required to promote the growth of At. An actively growing culture of L. The highest total new cell production and maximum specific growth rates from the stationary phase inocula were observed with CO 2 inlet concentrations less than that of air.

In contrast, the amount of CO 2 fixed per new cell produced increased with increasing inlet CO 2 concentrations above ppm.

Where inlet gas CO 2 concentrations were increased above that of air the additional CO 2 was consumed by the organisms but did not lead to increased cell production or significantly increase performance in terms of iron oxidation.

  DIFERENCIAS ENTRE EXOTOXINAS Y ENDOTOXINAS PDF

It is proposed that At. Finally, the results demonstrate the limitations of using CO 2 uptake or ferrous iron oxidation data as indirect measures of cell growth and. Bioinformatic prediction of gene functions regulated by quorum sensing in the bioleaching bacterium Acidithiobacillus ferrooxidans. The biomining bacterium Acidithiobacillus ferrooxidans oxidizes sulfide ores and promotes metal solubilization.

The efficiency of this process depends on the attachment of cells leptospigillum surfaces, a process regulated by quorum sensing QS cell-to-cell signalling in many Gram-negative bacteria.

bacterium leptospirillum ferrooxidans: Topics by

However, direct targets of the QS transcription factor AfeR remain unknown. In this study, a bioinformatic approach was used to infer possible AfeR direct targets based on the particular palindromic features of the AfeR binding leptospiirllum. A set of Hidden Markov Models designed to maintain palindromic regions and vary non-palindromic regions was used to screen for putative binding sites. By annotating the context of each predicted binding site PBSwe classified them according to their positional coherence relative to other putative genomic structures such as start codons, RNA polymerase promoter elements and intergenic regions.

In summary, leptospurillum target-genes were derrooxidans, 34 of which have a higher confidence level. Among the identified genes, we found ferrooxjdans itself, zwf, genes encoding glycosyltransferase activities, metallo-beta lactamases, and active transport-related proteins.

Glycosyltransferases and Zwf Glucose 6-phosphatedehydrogenase might be directly involved in polysaccharide biosynthesis and attachment to minerals by At. Growth of the acidophilic iron-sulfur bacterium Acidithiobacillus ferrooxidans under Mars-like geochemical conditions. Even in a desiccated environment, A.

Low temperature and low oxygen pressure were favorable to survival.

Leptospirillum ferrooxidans L15 | Type strain | DSM , ATCC , VKM B | BacDiveID

Thus, the acidophilic iron-sulfur bacterium A. As an autotroph it would be located at the base of such a food web, providing organic carbon. Suppression of pyritic sulphur during flotation tests using the bacterium Thiobacillus ferrooxidans. Environmental concern about sulphur dioxide emissions has led to the examination of the possibility of removing pyritic sulphur from coal prior to combustion during froth flotation, a routine method for coal cleaning at the pit-head.

The natural floatability of pyrite was significantly reduced in the Hallimond tube following 2. The suppression effect was greatly enhanced in the presence of Thiobacillus ferrooxidans.

A bacterial suspension in pH 2. The optimum bacterial density was 3. The degree of suppression by the cells was related to particle size but not to pH or temperature. It is postulated that pyrite removal in coals which are cleaned by froth flotation could be significantly reduced using a bacterial preconditioning stage with a short residence time of 2.

Members of the genus Leptospirillum are aerobic iron-oxidizing bacteria belonging to the phylum Nitrospira. They are important members of microbial communities that catalyze the biomining of sulfidic ores, thereby solubilizing metal ions.

Leptospirillum

These microorganisms live under extremely acidic and metal-loaded environments and thus must tolerate high concentrations of reactive oxygen species ROS.

Cobalamin vitamin B12 is a cobalt-containing tetrapyrrole cofactor involved in intramolecular rearrangement reactions and has recently been suggested to be an intracellular antioxidant.

In this work, we investigated the effect of the exogenous addition of cobalamin on oxidative stress parameters in Leptospirillum group II strain CF Our results revealed that the external supplementation of cobalamin reduces the levels of intracellular ROSs and the damage to biomolecules, and also stimulates the growth and survival of cells exposed to oxidative stress exerted by ferric ion, hydrogen peroxide, chromate and diamide.

Furthermore, exposure of strain CF-1 to oxidative stress elicitors resulted in the transcriptional activation of the cbiA gene encoding CbiA of the cobalamin biosynthetic pathway.

Altogether, these data suggest that cobalamin plays an important role in redox protection of Leptospirillum strain CF-1, supporting survival of this microorganism under extremely oxidative environmental conditions.

Understanding the mechanisms underlying the protective effect of cobalamin against oxidative stress may help to develop strategies to make biomining processes more effective. A new group in the Leptospirillum clade: These bacteria play important roles in environmental acidification and are harnessed for bioleaching-based metal recovery.

Known members of the Leptospirillum clade of the Nitrospira phylum are Leptospirillum ferrooxidans group ILeptospirillum ferriphilum and Leptospirillum rubarum group IIand Leptospirillum ferrodiazotrophum group III.

These biofilms typically also contain a variety of Archaea, Actinobacteria, and a few other Leptospirillum spp. The presence of nitrogen fixation and reverse tricarboxylic acid TCA cycle proteins suggest an autotrophic metabolism similar to that of L. Community transcriptomic and proteomic analyses demonstrate expression of a multicopper oxidase unique to this species, as well as hydrogenases and core metabolic genes. Results suggest that the Leptospirillum group IV UBA BS species might play important roles in carbon fixation, nitrogen fixation, hydrogen metabolism, and iron oxidation in some acidic environments.

  BRYAN CHAPELL CHRIST CENTERED PREACHING PDF

ICE Afe 1, an actively excising genetic element from the biomining bacterium Acidithiobacillus ferrooxidans. Integrative conjugative elements ICEs are self-transferred mobile genetic elements that contribute to horizontal gene transfer.

Excision of the element and expression of relevant genes under normal and DNA-damaging growth conditions was analyzed. Bioinformatic tools and DNA amplification methods were used to identify and to assess the excision and expression of genes related to the mobility of the element. The presence of a complete set of genes encoding self-transfer functions that are induced in response to DNA damage caused by mitomycin C additionally suggests that this element is capable of conjugative transfer to suitable recipient strains.

Transfer of ICEAfe1 may provide selective advantages to other acidophiles in this ecological niche through dissemination of gene clusters expressing transfer RNAs, CRISPRs, and exopolysaccharide biosynthesis enzymes, probably by modification of translation efficiency, resistance to bacteriophage infection and biofilm formation, respectively.

These data open novel avenues of research on conjugative transformation of biotechnologically relevant microorganisms recalcitrant to genetic manipulation.

AHL signaling molecules with a large acyl chain enhance biofilm formation on sulfur and metal sulfides by the bioleaching bacterium Acidithiobacillus ferrooxidans.

Biofilm formation plays a pivotal role in bioleaching activities of bacteria in both industrial and natural environments. Here, by visualizing attached bacterial cells on energetic substrates with different microscopy techniques, we obtained the first direct evidence that it is possible to positively modulate biofilm formation of the extremophilic bacterium Acidithiobacillus ferrooxidans on sulfur and pyrite surfaces by using Quorum Sensing molecules of the N-acylhomoserine lactone type AHLs.

Our results revealed that AHL-signaling molecules with a long acyl chain 12 or 14 carbons increased the adhesion of A. Finally, we demonstrated that this improvement of cell adhesion is correlated with an increased production of extracellular polymeric substances.

Genomic insights into the iron uptake mechanisms of the biomining microorganism Acidithiobacillus ferrooxidans. Commercial bioleaching of copper and the biooxidation of gold is a cost-effective and environmentally friendly process for metal recovery.

A partial genome sequence of the acidophilic, ferrloxidans bacterium Acidithiobacillus ferrooxidans is available from two public sources. This information has been used to build preliminary models that describe how this microorganism ferroxidans unusually high iron loads in the extremely acidic conditions pH 2 found in natural environments and in bioleaching operations.

Predicted proteins exhibit significant amino acid similarity with known proteins from neutrophilic organisms, including conservation of functional motifs, permitting their identification by bioinformatics tools and allowing the recognition of common themes in iron transport across distantly related species. However, significant differences in amino acid sequence leptospirilllum detected in pertinent domains that suggest ways in terrooxidans the periplasmic and outer membrane proteins of A.

Unexpectedly, the microorganism also contains candidate genes, organized in operon-like structures that potentially encode at least 11 siderophore systems for the uptake of Fe IIIalthough it does not exhibit genes that could encode the biosynthesis of the siderophores themselves.

It may also help to explain why it cannot tolerate high Fe III concentrations in bioleaching operations where it is out-competed by Leptospirillum species. Selective Adhesion of Thiobacillus ferrooxidans to Pyrite. Bacterial adhesion to mineral ferrooxidns plays an important ferropxidans not only in bacterial survival in natural ecosystems, but also in mining industry applications. Selective adhesion was investigated with Thiobacillus ferrooxidans by using four minerals, pyrite, quartz, chalcopyrite, and galena.

Escherichia coli was used as a control bacterium. Contact angles were used as indicators of hydrophobicity, which was an important factor in the interaction between minerals and bacteria. The contact angle of E. Ferrous ion inhibited the selective adhesion of T.