Project description:Full title: Environmental transcriptome analysis of LfeRT32a in its natural microbial community comparing the biofilm and planktonic modes of life. Extreme acidic environments are characterized among other features by the high metal content and the lack of nutrients (oligotrophy). Macroscopic biofilms and filaments usually grow on the water-air interface or under the stream attached to solid substrates (streamers). In the Tinto River (Spain), brown filaments develop under the water stream where the Gram-negative iron-oxidizing bacteria Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans are abundant. Both microorganisms play a critical role in bioleaching processes for industrial (biominery) and environmental applications (acid mine drainage, bioremediation). The aim of this study was to investigate the physiological differences between the free living (planktonic) and the sessile (biofilm associated) lifestyles of L. ferrooxidans as part of a natural extremely acidophilic community.
Project description:Acidithiobacillus ferrooxidans (A. ferrooxidans) ATCC 23270 is a model bacteria for bioleaching research. Because of the use of extractant in metal extraction industry, A. ferrooxidans needs to cope with the water-organic two-phase system. To get insight into the molecular response of A. ferrooxidans to organic solvent, global gene expression pattern was examined in A. ferrooxidans ATCC 23270 cells subjected to Lix984n (an organic extractant) using the method of whole-genome DNA microarray. The data suggested that the global response of A. ferrooxidans to Lix984n stress was characterized by the up-regulation of genes involved in pentose phosphate pathway, fatty acid and glutamate biosynthesis contrary to the significant down-regulation of the majority motility-related genes. In further study, compared to heterotrophic bacteria in dealing with short-time stress, A. ferrooxidans has a special strategy of continuously enhancing the expression of genes encoding proteins involved in electron transport, such as petI, petII, cyo and cyd. Besides, acrAB-tolC operon encoding organic solvent efflux pump and its positive regulator gene ostR were addressed.
Project description:Acidithiobacillus ferrooxidans (A. ferrooxidans) ATCC 23270 is a model bacteria for bioleaching research. Because of the use of extractant in metal extraction industry, A. ferrooxidans needs to cope with the water-organic two-phase system. To get insight into the molecular response of A. ferrooxidans to organic solvent, global gene expression pattern was examined in A. ferrooxidans ATCC 23270 cells subjected to Lix984n (an organic extractant) using the method of whole-genome DNA microarray. The data suggested that the global response of A. ferrooxidans to Lix984n stress was characterized by the up-regulation of genes involved in pentose phosphate pathway, fatty acid and glutamate biosynthesis contrary to the significant down-regulation of the majority motility-related genes. In further study, compared to heterotrophic bacteria in dealing with short-time stress, A. ferrooxidans has a special strategy of continuously enhancing the expression of genes encoding proteins involved in electron transport, such as petI, petII, cyo and cyd. Besides, acrAB-tolC operon encoding organic solvent efflux pump and its positive regulator gene ostR were addressed. In this work, the whole-genome array was employed to conduct the time-course transcriptome analysis of A. ferrooxidans ATCC 23270 in response to 1% (v/v) Lix984n for 5, 20, 40, and 80 min.
Project description:The deleterious fluoride ions, which released from fluoride in uranium during its bioleaching, strongly influenced microbial growth, energy intake, enzyme activity and relative metabolism. Whole-genome microarrays were used to obtain a comprehensive description of the molecular response by A. ferrooxidans ATCC 23270 at 4.8 mM fluoride stress.
Project description:(from abstract): Iron oxidation is a desirable trait of biomining microorganisms, although the mechanism is not well-understood in extreme thermoacidophiles. The complete genome sequence of the extremely thermoacidophilic archaeon Metallosphaera sedula DSM 5348 (2.2 Mb, ~2300 ORFs) provides insights into biologically catalyzed metal sulfide oxidation. Comparative genomics was used to identify pathways and proteins (in)directly involved with bioleaching. As expected, the M. sedula genome encodes genes related to autotrophic carbon fixation, metal tolerance, and adhesion. Also, terminal oxidase cluster organization indicates the presence of hybrid quinol-cytochrome oxidase complexes. Comparisons with the mesophilic biomining bacterium Acidithiobacillus ferrooxidans ATCC 23270 indicate that the M. sedula genome encodes at least one putative rusticyanin, involved in iron oxidation. The fox gene cluster, involved in iron oxidation in the thermoacidophilic archaeon Sulfolobus metallicus, could also be identified. These iron-oxidizing components are missing from genomes of non-leaching Sulfolobales like Sulfolobus solfataricus P2 and Sulfolobus acidocaldarius DSM 639. Whole genome transcriptional response analysis showed that 88 ORFs were up-regulated 2-fold or more in M. sedula upon addition of ferrous sulfate to yeast extract-based medium; these included components of terminal oxidase clusters predicted to be involved with iron oxidation, as well as genes predicted to be involved with sulfur metabolism. Many hypothetical proteins were also differentially transcribed, indicating that aspects of the iron and sulfur metabolism of M. sedula remain to be identified and characterized. Keywords: substrate response
Project description:The ideal genome sequence for medical interpretation is complete and diploid, capturing the full spectrum of genetic variation. Toward this end, there has been progress in discovery of single nucleotide polymorphism (SNP) and small (<10bp) insertion/deletions (indels), but annotation of larger structural variation (SV) including copy number variation (CNV) has been less comprehensive, even with available diploid sequence assemblies. We applied a multi-step sequence and microarray-based analysis to identify numerous previously unknown SVs within the first genome sequence reported from an individual.
Project description:The ideal genome sequence for medical interpretation is complete and diploid, capturing the full spectrum of genetic variation. Toward this end, there has been progress in discovery of single nucleotide polymorphism (SNP) and small (<10bp) insertion/deletions (indels), but annotation of larger structural variation (SV) including copy number variation (CNV) has been less comprehensive, even with available diploid sequence assemblies. We applied a multi-step sequence and microarray-based analysis to identify numerous previously unknown SVs within the first genome sequence reported from an individual.
Project description:The ideal genome sequence for medical interpretation is complete and diploid, capturing the full spectrum of genetic variation. Toward this end, there has been progress in discovery of single nucleotide polymorphism (SNP) and small (<10bp) insertion/deletions (indels), but annotation of larger structural variation (SV) including copy number variation (CNV) has been less comprehensive, even with available diploid sequence assemblies. We applied a multi-step sequence and microarray-based analysis to identify numerous previously unknown SVs within the first genome sequence reported from an individual.