scholarly journals Conserving a Volatile Metabolite: a Role for Carboxysome-Like Organelles in Salmonella enterica

2006 ◽  
Vol 188 (8) ◽  
pp. 2865-2874 ◽  
Author(s):  
Joseph T. Penrod ◽  
John R. Roth
Keyword(s):  
Salmonella Enterica ◽  
Sole Source ◽  
Low Ph ◽  
Carbon And Nitrogen ◽  
Volatile Metabolite ◽  
Volatile Metabolites ◽  
Shell Proteins ◽  
Carbon Retention

ABSTRACT Salmonellae can use ethanolamine (EA) as a sole source of carbon and nitrogen. This ability is encoded by an operon (eut) containing 17 genes, only 6 of which are required under standard conditions (37°C; pH 7.0). Five of the extra genes (eutM, -N, -L, -K, and -G) become necessary under conditions that favor loss of the volatile intermediate, acetaldehyde, which escapes as a gas during growth on EA and is lost at a higher rate from these mutants. The eutM, -N, -L, and -K genes encode homologues of shell proteins of the carboxysome, an organelle shown (in other organisms) to concentrate CO2. We propose that carboxysome-like organelles help bacteria conserve certain volatile metabolites—CO2 or acetaldehyde—perhaps by providing a low-pH compartment. The EutG enzyme converts acetaldehyde to ethanol, which may improve carbon retention by forming acetals; alternatively, EutG may recycle NADH within the carboxysome.

scholarly journals A pH-Sensitive Function and Phenotype: Evidence that EutH Facilitates Diffusion of Uncharged Ethanolamine in Salmonella enterica

2004 ◽  
Vol 186 (20) ◽  
pp. 6885-6890 ◽  
Author(s):  
Joseph T. Penrod ◽  
Christopher C. Mace ◽  
John R. Roth
Keyword(s):  
Membrane Protein ◽  
Salmonella Enterica ◽  
Sole Source ◽  
Low Ph ◽  
Ph Sensitive ◽  
External Concentration ◽  
Influx Rate ◽  
Sensitive Function ◽  
Degradative Enzyme

ABSTRACT The eutH gene is part of an operon that allows Salmonella enterica to use ethanolamine as a sole source of nitrogen, carbon, and energy. Although the sequence of EutH suggests a role in transport, eutH mutants use ethanolamine normally under standard conditions (pH 7.0). These mutants fail to use ethanolamine at a low pH. Evidence is presented that protonated ethanolamine (Eth0) does not enter cells, while uncharged ethanolamine (Eth0) diffuses freely across the membrane. The external concentration of Eth0 varies with the pH (pK = 9.5). At pH 7.0, the standard ethanolamine concentration (41 mM) provides enough Eth0 for an influx rate that can support growth with or without EutH. When a lowered pH and/or ethanolamine concentration reduced the Eth0 concentration below 25 μM, EutH was needed to facilitate diffusion. EutH+ cells grew normally at Eth0 concentrations above 3 μM, close to the Km (9 μM) of the first degradative enzyme, ethanolamine ammonia lyase. It is suggested that EutH facilitates diffusion of Eth0. As predicted for a transporter, EutH contributed to the toxicity of ethanolamine seen under some conditions; furthermore, fusion of EutH to fluorescent Yfp protein provided evidence that EutH is a membrane protein.

Decolorisation of natural organic matter by Phanerochaete chrysosporium: the effect of environmental conditions

2004 ◽  
Vol 4 (4) ◽  
pp. 175-182 ◽  
Author(s):  
K. Rojek ◽  
F.A. Roddick ◽  
A. Parkinson
Keyword(s):  
Organic Matter ◽  
Ionic Strength ◽  
Natural Organic Matter ◽  
Phanerochaete Chrysosporium ◽  
Fungal Growth ◽  
Low Ph ◽  
Colour Removal ◽  
Humic Material ◽  
Carbon And Nitrogen ◽  
Carbon And Nitrogen Content

Phanerochaete chrysosporium was shown to rapidly decolorise a solution of natural organic matter (NOM). The effect of various parameters such as carbon and nitrogen content, pH, ionic strength, NOM concentration and addition of Mn2+ on the colour removal process was investigated. The rapid decolorisation was related to fungal growth and biosorption rather than biodegradation as neither carbon nor nitrogen limitation, nor Mn2+ addition, triggered the decolorisation process. Low pH (pH 3) and increased ionic strength (up to 50 g L‒1 added NaCl) led to greater specific removal (NOM/unit biomass), probably due to increased electrostatic bonding between the humic material and the biomass. Adsorption of NOM with viable and inactivated (autoclaved or by sodium azide) fungal pellets occurred within 24 hours and the colour removal depended on the viability, method of inactivation and pH. Colour removal by viable pellets was higher under the same conditions, and this, combined with desorption data, confirmed that fungal metabolic activity was important in the decolorisation process. Overall, removals of up to 40–50% NOM from solution were obtained. Of this, removal by adsorption was estimated as 60–70%, half of which was physicochemical, the other half metabolically-dependent biosorption and bioaccumulation. The remainder was considered to be removed by biodegradation, although some of this may be ascribed to bioaccumulation and metabolically-dependent biosorption.

Activation of hilA expression at low pH requires the signal sensor CpxA, but not the cognate response regulator CpxR, in Salmonella enterica serovar Typhimurium

Microbiology ◽  
2003 ◽  
Vol 149 (10) ◽  
pp. 2809-2817 ◽  
Author(s):  
Shu-ichi Nakayama ◽  
Akira Kushiro ◽  
Takashi Asahara ◽  
Ryu-ichiro Tanaka ◽  
Lan Hu ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Cell Invasion ◽  
Salmonella Enterica ◽  
Response Regulator ◽  
Low Ph ◽  
Apparent Difference ◽  
Virulence Determinants ◽  
Serovar Typhimurium ◽  
Cognate Response Regulator ◽  
Invasion Capacity

A two-component regulatory system, cpxR–cpxA, plays an important role in the pH-dependent regulation of virF, a global activator for virulence determinants including invasion genes, in Shigella sonnei. The authors examined whether the cpxR–cpxA homologues have some function in the expression of Salmonella enterica serovar Typhimurium invasion genes via the regulation of hilA, an activator for these genes. In a Salmonella cpxA mutant, the hilA expression level was reduced to less than 10 % of that in the parent strain at pH 6·0. This mutant strain also showed undetectable synthesis of an invasion gene product, SipC, at pH 6·0 and reduced cell invasion capacity – as low as 20 % of that of the parent. In this mutant, the reduction in hilA expression was much less marked at pH 8·0 than at pH 6·0 – no less than 50 % of that in the parent, and no significant reduction was observed in either SipC synthesis or cell invasion rate, compared to the parent. Unexpectedly, a Salmonella cpxR mutant strain and the parent showed no apparent difference in all three characteristics described above at either pH. These results indicate that in Salmonella, the sensor kinase CpxA activates hilA, and consequently, invasion genes and cell invasion capacity at pH 6·0. At pH 8·0, however, CpxA does not seem to have a large role in activation of these factors. Further, the results show that this CpxA-mediated activation does not require its putative cognate response regulator, CpxR. This suggests that CpxA may interact with regulator(s) other than CpxR to achieve activation at low pH.

scholarly journals Amino Acid-Mediated Induction of the Basic Amino Acid-Specific Outer Membrane Porin OprD from Pseudomonas aeruginosa

1999 ◽  
Vol 181 (17) ◽  
pp. 5426-5432 ◽  
Author(s):  
Martina M. Ochs ◽  
Chung-Dar Lu ◽  
Robert E. W. Hancock ◽  
Ahmed T. Abdelal
Keyword(s):  
Amino Acids ◽  
Pseudomonas Aeruginosa ◽  
Amino Acid ◽  
Regulatory Protein ◽  
Basic Amino Acid ◽  
Sole Source ◽  
Activation Mechanism ◽  
Beta Lactam ◽  
Mobility Shift ◽  
Carbon And Nitrogen

ABSTRACT Pseudomonas aeruginosa can utilize arginine and other amino acids as both carbon and nitrogen sources. Earlier studies have shown that the specific porin OprD facilitates the diffusion of basic amino acids as well as the structurally analogous beta-lactam antibiotic imipenem. The studies reported here showed that the expression of OprD was strongly induced when arginine, histidine, glutamate, or alanine served as the sole source of carbon. The addition of succinate exerted a negative effect on induction ofoprD, likely due to catabolite repression. The arginine-mediated induction was dependent on the regulatory protein ArgR, and binding of purified ArgR to its operator upstream of theoprD gene was demonstrated by gel mobility shift and DNase assays. The expression of OprD induced by glutamate as the carbon source, however, was independent of ArgR, indicating the presence of more than a single activation mechanism. In addition, it was observed that the levels of OprD responded strongly to glutamate and alanine as the sole sources of nitrogen. Thus, that the expression ofoprD is linked to both carbon and nitrogen metabolism ofPseudomonas aeruginosa.

scholarly journals Molecular Mechanism ofN,N-Dimethylformamide Degradation inMethylobacteriumsp. Strain DM1

2019 ◽  
Vol 85 (12) ◽  
Author(s):  
Xinyu Lu ◽  
Weiwei Wang ◽  
Lige Zhang ◽  
Haiyang Hu ◽  
Ping Xu ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Gene Clusters ◽  
Sole Source ◽  
Human Beings ◽  
Sequencing Data ◽  
Carbon And Nitrogen ◽  
Redundant Genes ◽  
Evolutionary Advantage ◽  
Redundant Gene ◽  
Phenotype Identification

ABSTRACTN,N-Dimethylformamide (DMF) is one of the most common xenobiotic chemicals, and it can be easily emitted into the environment, where it causes harm to human beings. Herein, an efficient DMF-degrading strain, DM1, was isolated and identified asMethylobacteriumsp. This strain can use DMF as the sole source of carbon and nitrogen. Whole-genome sequencing of strain DM1 revealed that it has a 5.66-Mbp chromosome and a 200-kbp megaplasmid. The plasmid pLVM1 specifically harbors the genes essential for the initial steps of DMF degradation, and the chromosome carries the genes facilitating subsequent methylotrophic metabolism. Through analysis of the transcriptome sequencing data, the complete mineralization pathway and redundant gene clusters of DMF degradation were elucidated. The dimethylformamidase (DMFase) gene was heterologously expressed, and DMFase was purified and characterized. Plasmid pLVM1 is catabolically crucial for DMF utilization, as evidenced by the phenotype identification of the plasmid-free strain. This study systematically elucidates the molecular mechanisms of DMF degradation byMethylobacterium.IMPORTANCEDMF is a hazardous pollutant that has been used in the chemical industry, pharmaceutical manufacturing, and agriculture. Biodegradation as a method for removing DMF has received increasing attention. Here, we identified an efficient DMF degrader,Methylobacteriumsp. strain DM1, and characterized the complete DMF mineralization pathway and enzymatic properties of DMFase in this strain. This study provides insights into the molecular mechanisms and evolutionary advantage of DMF degradation facilitated by plasmid pLVM1 and redundant genes in strain DM1, suggesting the emergence of new ecotypes ofMethylobacterium.

Biodegradation of cyanide by Rhodococcus UKMP-5M

Biologia ◽  
2013 ◽  
Vol 68 (2) ◽  
Author(s):  
Maegala Nallapan Maniyam ◽  
Fridelina Sjahrir ◽  
Abdul Ibrahim ◽  
Anthony Cass
Keyword(s):  
Contaminated Soils ◽  
Nitrile Hydratase ◽  
Sole Source ◽  
Optimum Conditions ◽  
Carbon And Nitrogen ◽  
Bacterial Enzyme ◽  
End Products ◽  
Treatment Facilities ◽  
Organic Nutrients ◽  
Structural Levels

AbstractA new bacterial strain, Rhodococcus UKMP-5M isolated from petroleum-contaminated soils demonstrated promising potential to biodegrade cyanide to non-toxic end-products. Ammonia and formate were found as final products during growth of the isolate with KCN as the sole nitrogen source. Formamide was not detected as one of the end-products suggesting that the biodegradation of cyanide by Rhodococcus UKMP-5M may have proceeded via a hydrolytic pathway involving the bacterial enzyme cyanidase. No growth of the bacterium was observed when KCN was supplied as the sole source of carbon and nitrogen even though marginal reduction in the concentration of cyanide was recorded, indicating the toxic effect of cyanide even in cyanide-degrading microorganisms. The cyanide biodegradation ability of Rhodococcus UKMP-5M was greatly affected by the presence of organic nutrients in the medium. Medium containing glucose and yeast extract promoted the highest growth rate of the bacterium which simultaneously assisted complete biodegradation of 0.1 mM KCN within 24 hours of incubation. It was found that growth and cyanide biodegradation occurred optimally at 30°C and pH 6.3 with glucose as the preferred carbon source. Acetonitrile was used as an inducer to enhance cyanide biodegradation since the enzymes nitrile hydratase and/or nitrilase have similarity at both the amino acid and structural levels to that of cyanidase. The findings from this study should be of great interest from an environmental and health point of views since the optimum conditions discovered in the present study bear a close resemblance to the actual scenario of cyanide wastewater treatment facilities.

Simultaneous degradation of acetonitrile and biphenyl by Pseudomonas aeruginosa

1991 ◽  
Vol 37 (6) ◽  
pp. 411-418 ◽  
Author(s):  
Mohamed S. Nawaz ◽  
Kirit D. Chapatwala
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Acetic Acid ◽  
Benzoic Acid ◽  
Sole Carbon Source ◽  
Nitrile Hydratase ◽  
Sole Source ◽  
Sole Nitrogen Source ◽  
Carbon And Nitrogen ◽  
Simultaneous Degradation ◽  
Key Words Biodegradation

A bacterium capable of utilizing either acetonitrile as the sole source of carbon and nitrogen or biphenyl as the sole source of carbon was isolated from soil and identified as Pseudomonas aeruginosa. The bacterium also utilized other nitriles, amides, and polychlorinated biphenyls (PCBs) as growth substrates. Acetonitrile- or biphenyl-grown cells oxidized these substrates without a lag. In studies with [14C]acetonitrile, nearly 74% of the carbon was recovered as 14CO2 and 8% was associated with the biomass. In studies with [14C]biphenyl, nearly 68% of the carbon was recovered as 14CO2 and nearly 6% was associated with the biomass. Although higher concentrations of acetonitrile as the sole sources of nitrogen inhibited the rates of [14C]biphenyl mineralization, lower concentrations (0.05%, w/v) gave a 77% stimulation in 14CO2 recovery. Pseudomonas aeruginosa metabolized acetonitrile to ammonia and acetic acid and biphenyl to benzoic acid. The bacterium also simultaneously utilized biphenyl as the sole carbon source and acetonitrile as the sole nitrogen source. However, biphenyl utilization increased only after the depletion of acetronitrile. Metabolites of the mixed substrate were ammonia and benzoic acid, which completely disappeared in the later stages of incubation. Nitrile hydratase and amidase were resposible for the transformation of acetonitrile to acetic acid and ammonia. Key words: biodegradation, acetonitrile, biphenyl, Pseudomonas aeruginosa.

Description of bacteria able to degrade isoquinoline in pure culture

1994 ◽  
Vol 40 (7) ◽  
pp. 555-560 ◽  
Author(s):  
J. Aislabie ◽  
N. K. Richards ◽  
T. C. Lyttle
Keyword(s):  
Heterocyclic Compound ◽  
Pure Culture ◽  
Sole Source ◽  
Broth Culture ◽  
Gram Negative ◽  
Carbon And Nitrogen ◽  
The Family ◽  
Nitrogen Heterocyclic

Isoquinoline is a nitrogen heterocyclic compound that is associated with coal- and oil-derived wastes. Four strains of bacteria able to degrade isoquinoline in pure culture were isolated from sites known to be contaminated with oil. Isoquinoline was used as the sole source of carbon and nitrogen by these isolates. Isoquinoline was initially transformed to 1-hydroxyisoquinoline, which accumulated in the broth culture, and then disappeared. The four strains isolated were Gram negative, aerobic, rod-shaped bacteria with polar flagella. The strains have been presumptively identified as members of the family Comamonadaceae.Key words: isoquinoline degradation, Comamonadaceae.not available

YELLOW CHROMOGENIC BACTERIA ON WHEAT: II. DETERMINATIVE STUDIES

1955 ◽  
Vol 1 (7) ◽  
pp. 479-485 ◽  
Author(s):  
Norman James
Keyword(s):  
Sole Source ◽  
Carbon And Nitrogen ◽  
Early Literature ◽  
Predominant Type ◽  
Xanthomonas Translucens

The predominant type of yellow chromogenic bacteria easily isolated from normal wheat and other seeds, and in the early literature referred to as Bacterium herbicola aureum Diiggeli, is like Xanthomonas translucens in many aspects—in morphology, colony characteristics, type of pigment, and habitat. These bacteria differ from the latter species in that they are not pathogenic and they grow moderately in a medium containing asparagine as the sole source of carbon and nitrogen. The problem of nomenclature of these bacteria is considered. Evidence that justifies acceptance of Pseudomonas trifolii Huss as the legitimate name of the species and transference of the species to the genus Xanthomonas is presented. The name Xanthomonas trifolii (Huss) comb. nov. is proposed.

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