Metabolism of Sulphur-Containing Organic Compounds

Kertesz, Michael A.

doi:10.1007/978-1-4419-9088-4_12

Cited by 15 publications

(21 citation statements)

References 125 publications

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“…This suggested that asfA might have been acquired by P. putida S‐313 via horizontal gene transfer from a β‐proteobacterium, especially as the sequenced strain of P. putida (strain KT2440) contains no asfA homologue. Indeed, sequence comparison of the regions flanking the P. putida S‐313 asf cluster suggests that it has been inserted into the PP180 gene of the P. putida genome (Kertesz, 2004). To test this hypothesis further, tetranucleotide frequencies were used to compare the affiliation of asfA from P. putida S‐313 with genes from a variety of other bacteria, including the ssuD genes from Escherichia coli , Ralstonia solanacearum , Polaromonas naphthalenivorans , P. putida KT2440, P. putida S‐313 and Bradyrhizobium sp.…”

Section: Discussionmentioning

confidence: 99%

Desulfurization of aromatic sulfonates by rhizosphere bacteria: high diversity of the asfA gene

Schmalenberger

Kertesz

2006

Environmental Microbiology

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The plant growth-promoting effect of Pseudomonas putida S-313 is associated with its ability to desulfurize arylsulfonates. To understand this further, other plant-associated bacteria able to desulfurize a range of arylsulfonates were isolated from the rhizospheres of winter and spring barley. The isolates belonged to the beta-proteobacteria, including bacteria from the Variovorax paradoxus group and from the Acidovorax genus. They desulfurized toluenesulfonate to p-cresol, and were found to contain orthologues of the P. putida S-313 asfA gene (> 70% sequence identity to AsfA), which is required for aryldesulfonation in this species. Further putative asfA orthologues were identified in several bacteria and cyanobacteria whose genomes have been sequenced, but of these only Cupriavidus (Ralstonia) metallidurans was able to utilize arylsulfonates as sulfur source. Cultivation of V. paradoxus, C. metallidurans or P. putida S-313 with toluenesulfonate as sulfur source led to a 100-fold increase in expression of the asfA homologues, which was largely repressed when sulfate was added. Polymerase chain reaction with degenerate primers was used to generate asfAB clone libraries from spring- and winter-barley rhizosphere DNA. Cluster analysis of 76 sequenced AsfA fragments revealed a broad diversity, with the majority of the sequences clustered together with AsfA from bacteria that are able to utilize toluenesulfonate as sulfur source. The diversity of asfA in barley rhizosphere underlines the importance of the desulfonation process for bacteria that inhabit the plant rhizosphere.

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Section: Discussionmentioning

confidence: 99%

Desulfurization of aromatic sulfonates by rhizosphere bacteria: high diversity of the asfA gene

Schmalenberger

Kertesz

2006

Environmental Microbiology

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“…Desulfation of the terminal sugars of mucin constitutes the first step in mucin degradation to provide carbon for growth but organisms like P. aeruginosa can also utilize human mucin as a source of sulfur (Tralau et al, 2007). Inorganic sulfate is the preferred sulfur source for P. aeruginosa (Hummerjohann et al, 1998) but if this is limited, P. aeruginosa is able to desulfurize a range of organosulfur compounds through expression of a range of loci involved in organosulfur utilization (Kertesz, 2004). Mucin desulfation may, therefore, be an alternative option for sulfur acquisition in the lung environment.…”

Section: Introductionmentioning

confidence: 99%

Desulfurization of mucin by Pseudomonas aeruginosa: influence of sulfate in the lungs of cystic fibrosis patients

Robinson

Elkins

Bialkowski

et al. 2012

Journal of Medical Microbiology

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Pseudomonas aeruginosa is a common cause of chronic respiratory infection in cystic fibrosis (CF) patients. Infection is established within the lung epithelial mucus layer through adhesion to mucins. Terminal residues on mucin oligosaccharide chains are highly sulfated and sialylated, which increases their resistance to degradation by bacterial enzymes. However, a number of microbes, including P. aeruginosa, display mucin sulfatase activity. Using ion chromatography, the levels of sulfation on different respiratory mucins and the availability of inorganic sulfate to pathogens in sputum from CF patients were quantified. The ability of clinical isolates of P. aeruginosa to desulfate mucin was tested by providing mucin as a sole sulfur source for growth. All tested P. aeruginosa strains isolated from the lungs of CF patients were able to use human respiratory mucin as a source of sulfur for growth, whereas other non-clinical species of the genus Pseudomonas were not. However, measured levels of inorganic sulfate in sputum from CF patients suggested that bacteria resident in the lung have sufficient inorganic sulfate for growth and are unlikely to require access to mucin sulfur as a sulfur source during chronic infection. This was confirmed when expression of sulfate-repressed P. aeruginosa genes atsK and msuE was found to be repressed in the sputum of CF patients, which was detected by using quantitative RT-PCR. These results indicate that sulfate starvation is unlikely to occur in pathogens residing in the sputum of CF patients and, therefore, mucin desulfation may have an alternative purpose in the association between P. aeruginosa and the airways of CF patients.

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“…Under these conditions, both the wild type and the ⌬rhdA mutant showed negligible thiocyanateforming capability compared with the corresponding clear lysates (0.38 and 0.31 versus 248.5 and 65.1 nmol min Ϫ1 mg Ϫ1 of total protein, respectively), even after addition of thiosulfate in a 200-fold molar excess over cyanide (data not shown). This could plausibly be explained by the impossibility for thiosulfate to cross the cytoplasmic membrane at sufficient rate (24) and by the inability of a cytoplasmic sulfurtransferase(s) to perform multiple persulfuration cycles. To investigate the involvement of RhdA in protection against exogenous cyanide, exponentialphase cultures of P. aeruginosa PAO1 and PAO1 ⌬rhdA carrying or not carrying the complementing plasmid pUCP4955-rhdA were challenged with 300 M KCN in LB medium.…”

Section: Resultsmentioning

confidence: 99%

Involvement of Pseudomonas aeruginosa Rhodanese in Protection from Cyanide Toxicity

Cipollone

Frangipani

Tiburzi

et al. 2007

Appl Environ Microbiol

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Cyanide is a serious environmental pollutant and a biocontrol metabolite in plant growth-promoting Pseudomonas species. Here we report on the presence of multiple sulfurtransferases in the cyanogenic bacterium Pseudomonas aeruginosa PAO1 and investigate in detail RhdA, a thiosulfate:cyanide sulfurtransferase (rhodanese) which converts cyanide to less toxic thiocyanate. RhdA is a cytoplasmic enzyme acting as the principal rhodanese in P. aeruginosa. The rhdA gene forms a transcriptional unit with the PA4955 and psd genes and is controlled by two promoters located upstream of PA4955 and rhdA. Both promoters direct constitutive RhdA expression and show similar patterns of activity, involving moderate down-regulation at the stationary phase or in the presence of exogenous cyanide. We previously observed that RhdA overproduction protects Escherichia coli against cyanide toxicity, and here we show that physiological RhdA levels contribute to P. aeruginosa survival under cyanogenic conditions. The growth of a ⌬rhdA mutant is impaired under cyanogenic conditions and fully restored upon complementation with rhdA. Wild-type P. aeruginosa outcompetes the ⌬rhdA mutant in cyanogenic coculture assays. Hence, RhdA could be regarded as an effector of P. aeruginosa intrinsic resistance to cyanide, insofar as it provides the bacterium with a defense mechanism against endogenous cyanide toxicity, in addition to cyanide-resistant respiration.

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Metabolism of Sulphur-Containing Organic Compounds

Cited by 15 publications

References 125 publications

Desulfurization of aromatic sulfonates by rhizosphere bacteria: high diversity of the asfA gene

Desulfurization of aromatic sulfonates by rhizosphere bacteria: high diversity of the asfA gene

Desulfurization of mucin by Pseudomonas aeruginosa: influence of sulfate in the lungs of cystic fibrosis patients

Involvement of Pseudomonas aeruginosa Rhodanese in Protection from Cyanide Toxicity

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