Adaptative biochemical pathways and regulatory networks in Klebsiella oxytoca BAS-10 producing a biotechnologically relevant exopolysaccharide during Fe(III)-citrate fermentation.

Abstract Background A bacterial strain previously isolated from pyrite mine drainage and named BAS-10 was tentatively identified as Klebsiella oxytoca. Unlikely other enterobacteria, BAS-10 is able to grow on Fe(III)-citrate as sole carbon and energy source, yielding acetic acid and CO2 coupled with Fe(III) reduction to Fe(II) and showing unusual physiological characteristics. In fact, under this growth condition, BAS-10 produces an exopolysaccharide (EPS) having a high rhamnose content and metal-binding properties, whose biotechnological applications were proven as very relevant. Results Further phylogenetic analysis, based on 16S rDNA sequence, definitively confirmed that BAS-10 belongs t…

Additional file 4: of Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Figure S1. K. oxytoca DSM 29614 grown in NaC (left) and in FeC medium (right) after 7 day of incubation at 30 °C. Figure S2. a,b) Production of ortorhomboidal struvite in the presence of Hg2+ (a) and Ag+ (b); both crystals precipitated in aerobic cultures of K. oxytoca DSM 29614. c,d) Micrographs of microcrystal of struvite by K. oxytoca DSM 29614 cells, grown in aerobic conditions in the presence of Pd2+ in transmission mode (c) and in fluorescence mode (d) with cells stained with DAPI. e) Micrographs of TEM of microcrystals of struvite coated by Pd2+. (PDF 527 kb)

Characterization of the bacterial community isolated from a High Middle Age soil sample dated since 980 AD

Anticancer activity of biogenerated silver nanoparticles: an integrated proteomic investigation

Silver nanoparticles (AgNPs), embedded into a specific polysaccharide (EPS), were biogenerated by Klebsiella oxytoca DSM 29614 under aerobic (AgNPs-EPSaer) and anaerobic conditions (AgNPs-EPSanaer). Both AgNPs-EPS matrices were tested by MTT assay for cytotoxic activity against human breast (SKBR3 and 8701-BC) and colon (HT-29, HCT 116 and Caco-2) cancer cell lines, revealing AgNPs-EPSaer as the most active, in terms of IC50, with a more pronounced efficacy against breast cancer cell lines. Therefore, colony forming capability, morphological changes, generation of reactive oxygen species (ROS), induction of apoptosis and autophagy, inhibition of migratory and invasive capabilities and prote…

Polysaccharide-based silver nanoparticles synthesized by Klebsiella oxytoca DSM 29614 cause DNA fragmentation in E-coli cells

Silver nanoparticles (AgNPs), embedded into a specific exopolysaccharide (EPS), were produced by Klebsiella oxytoca DSM 29614 by adding AgNO3 to the cultures during exponential growth phase. In particular, under aerobic or anaerobic conditions, two types of silver nanoparticles, named AgNPs-EPS(aer) and the AgNPs-EPS(anaer), were produced respectively. The effects on bacterial cells was demonstrated by using Escherichia coli K12 and Kocuria rhizophila ATCC 9341 (ex Micrococcus luteus) as Gram-negative and Gram-positive tester strains, respectively. The best antimicrobial activity was observed for AgNPs-EPS(aer), in terms of minimum inhibitory concentrations and minimum bactericidal concentr…

Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Background Klebsiella oxytoca DSM 29614 - isolated from acid mine drainages - grows anaerobically using Fe(III)-citrate as sole carbon and energy source, unlike other enterobacteria and K. oxytoca clinical isolates. The DSM 29614 strain is multi metal resistant and produces metal nanoparticles that are embedded in its very peculiar capsular exopolysaccharide. These metal nanoparticles were effective as antimicrobial and anticancer compounds, chemical catalysts and nano-fertilizers. Results The DSM 29614 strain genome was sequenced and analysed by a combination of in silico procedures. Comparative genomics, performed between 85 K. oxytoca representatives and K. oxytoca DSM 29614, revealed th…

Biogenic iron-silver nanoparticles inhibit bacterial biofilm formation due to Ag+ release as determined by a novel phycoerythrin-based assay

Silver nanoparticles (Ag-NPs) can be considered as a cost-effective alternative to antibiotics. In the presence of Fe(III)-citrate and Ag+, Klebsiella oxytoca DSM 29614 produces biogenic Ag-NPs embedded in its peculiar exopolysaccharide (EPS). K. oxytoca DSM 29614 was cultivated in a defined growth medium–containing citrate (as sole carbon source) and supplemented with Ag+ and either low or high Fe(III) concentration. As inferred from elemental analysis, transmission and scanning electron microscopy, Fourier transform infrared spectrometry and dynamic light scattering, Ag-EPS NPs were produced in both conditions and contained also Fe. The production yield of high-Fe/Ag-EPS NPs was 12 times …

Additional file 5: of Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Supporting Information. (PDF 130 kb)

Additional file 5: of Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Supporting Information. (PDF 130 kb)

Additional file 4: of Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Figure S1. K. oxytoca DSM 29614 grown in NaC (left) and in FeC medium (right) after 7 day of incubation at 30 °C. Figure S2. a,b) Production of ortorhomboidal struvite in the presence of Hg2+ (a) and Ag+ (b); both crystals precipitated in aerobic cultures of K. oxytoca DSM 29614. c,d) Micrographs of microcrystal of struvite by K. oxytoca DSM 29614 cells, grown in aerobic conditions in the presence of Pd2+ in transmission mode (c) and in fluorescence mode (d) with cells stained with DAPI. e) Micrographs of TEM of microcrystals of struvite coated by Pd2+. (PDF 527 kb)

Novel Sources of Biodiversity and Biomolecules from Bacteria Isolated from a High Middle Ages Soil Sample in Palermo (Sicily, Italy)

: The urban plan of Palermo (Sicily, Italy) has evolved throughout Punic, Roman, Byzantine, Arab, and Norman ages until it stabilized within the borders that correspond to the current historic center. During the 2012 to 2013 excavation campaign, new remains of the Arab settlement, directly implanted above the structures of the Roman age, were found. The materials investigated in this study derived from the so-called Survey No 3, which consists of a rock cavity of subcylindrical shape covered with calcarenite blocks: it was probably used to dispose of garbage during the Arabic age and its content, derived from daily activities, included grape seeds, scales and bones of fish, small animal bon…

Additional file 6: of Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Table S4. List of genes associate with cps1 cluster in DSM 29614 strain. (XLSX 10 kb)

Additional file 2: of Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Table S2. List of differentially abundant proteins in DSM 29614 strain used for protein functional enrichment analysis. (XLSX 17 kb)

Additional file 1: of Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Table S1. List of genomes of K. oxytoca strains used for comparative genomics. (XLSX 10 kb)

Additional file 3: of Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Table S3. List of metal resistance genes identified in the DSM 29614 strain genome. (XLSX 48 kb)

Additional file 6: of Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Table S4. List of genes associate with cps1 cluster in DSM 29614 strain. (XLSX 10 kb)

Additional file 3: of Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Table S3. List of metal resistance genes identified in the DSM 29614 strain genome. (XLSX 48 kb)

Additional file 2: of Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Table S2. List of differentially abundant proteins in DSM 29614 strain used for protein functional enrichment analysis. (XLSX 17 kb)