Cloning of a Novel 6-Chloronicotinic Acid Chlorohydrolase from the Newly Isolated 6-Chloronicotinic Acid Mineralizing Bradyrhizobiaceae Strain SG-6C

Shettigar, Madhura; Pearce, Stephen L.; Khan, Fazlurrahman; Dorrian, Susan J.; Balotra, Sahil; Russell, Robyn J.; Oakeshott, John G.; Pandey, Gyanendra

doi:10.1371/journal.pone.0051162

Cited by 21 publications

(14 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Resting cell studies were performed with minor modification of the method described earlier [20]. Briefly, a seed culture (6%, v/v) of strain MB-P1 grown in 1/4-NB inoculated into 1.6 L of 1/4-NB supplemented with 200 µM of 2-C-4-NA and incubated at 30°C with aeration for 24 h (OD 600 , 1.3–1.4).…”

Section: Methodsmentioning

confidence: 99%

Metabolism of 2-Chloro-4-Nitroaniline via Novel Aerobic Degradation Pathway by Rhodococcus sp. Strain MB-P1

et al. 2013

Self Cite

View full text Add to dashboard Cite

2-chloro-4-nitroaniline (2-C-4-NA) is used as an intermediate in the manufacture of dyes, pharmaceuticals, corrosion inhibitor and also used in the synthesis of niclosamide, a molluscicide. It is marked as a black-listed substance due to its poor biodegradability. We report biodegradation of 2-C-4-NA and its pathway characterization by Rhodococcus sp. strain MB-P1 under aerobic conditions. The strain MB-P1 utilizes 2-C-4-NA as the sole carbon, nitrogen, and energy source. In the growth medium, the degradation of 2-C-4-NA occurs with the release of nitrite ions, chloride ions, and ammonia. During the resting cell studies, the 2-C-4-NA-induced cells of strain MB-P1 transformed 2-C-4-NA stoichiometrically to 4-amino-3-chlorophenol (4-A-3-CP), which subsequently gets transformed to 6-chlorohydroxyquinol (6-CHQ) metabolite. Enzyme assays by cell-free lysates prepared from 2-C-4-NA-induced MB-P1 cells, demonstrated that the first enzyme in the 2-C-4-NA degradation pathway is a flavin-dependent monooxygenase that catalyzes the stoichiometric removal of nitro group and production of 4-A-3-CP. Oxygen uptake studies on 4-A-3-CP and related anilines by 2-C-4-NA-induced MB-P1 cells demonstrated the involvement of aniline dioxygenase in the second step of 2-C-4-NA degradation. This is the first report showing 2-C-4-NA degradation and elucidation of corresponding metabolic pathway by an aerobic bacterium.

show abstract

Section: Methodsmentioning

confidence: 99%

Metabolism of 2-Chloro-4-Nitroaniline via Novel Aerobic Degradation Pathway by Rhodococcus sp. Strain MB-P1

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…Resting cell studies on MNA degradation were carried out according to the method described elsewhere [18]. The overnight 1/4-NB grown seed culture (6%, v/v) of strain FK357 was inoculated into 1.0 L of 1/4-NB supplemented with MNA (150 µM) and incubated at 30°C under shaking at 200 rpm up to 24 hours.…”

Section: Methodsmentioning

confidence: 99%

Aerobic Degradation of N-Methyl-4-Nitroaniline (MNA) by Pseudomonas sp. Strain FK357 Isolated from Soil

et al. 2013

Self Cite

View full text Add to dashboard Cite

N-Methyl-4-nitroaniline (MNA) is used as an additive to lower the melting temperature of energetic materials in the synthesis of insensitive explosives. Although the biotransformation of MNA under anaerobic condition has been reported, its aerobic microbial degradation has not been documented yet. A soil microcosms study showed the efficient aerobic degradation of MNA by the inhabitant soil microorganisms. An aerobic bacterium, Pseudomonas sp. strain FK357, able to utilize MNA as the sole carbon, nitrogen, and energy source, was isolated from soil microcosms. HPLC and GC-MS analysis of the samples obtained from growth and resting cell studies showed the formation of 4-nitroaniline (4-NA), 4-aminophenol (4-AP), and 1, 2, 4-benzenetriol (BT) as major metabolic intermediates in the MNA degradation pathway. Enzymatic assay carried out on cell-free lysates of MNA grown cells confirmed N-demethylation reaction is the first step of MNA degradation with the formation of 4-NA and formaldehyde products. Flavin-dependent transformation of 4-NA to 4-AP in cell extracts demonstrated that the second step of MNA degradation is a monooxygenation. Furthermore, conversion of 4-AP to BT by MNA grown cells indicates the involvement of oxidative deamination (release of NH2 substituent) reaction in third step of MNA degradation. Subsequent degradation of BT occurs by the action of benzenetriol 1, 2-dioxygenase as reported for the degradation of 4-nitrophenol. This is the first report on aerobic degradation of MNA by a single bacterium along with elucidation of metabolic pathway.

show abstract

“…In order to identify the metabolic intermediates of m -tyrosine catabolic pathway in strain SSC5, a resting cell study was carried out according to the method described elsewhere [35]. A volume of 1.6 liter of 1/4-NB supplemented with m -tyrosine (300 µM) was inoculated with an overnight 1/4-NB grown seed culture (6%, v/v) of strain SSC5 and was incubated at 30°C under shaking at 200 rpm up to 24 hours.…”

Section: Methodsmentioning

confidence: 99%

Biodegradation of the Allelopathic Chemical m-Tyrosine by Bacillus aquimaris SSC5 Involves the Homogentisate Central Pathway

2013

Self Cite

View full text Add to dashboard Cite

m-Tyrosine is an amino acid analogue, exuded from the roots of fescue grasses, which acts as a potent allelopathic and a broad spectrum herbicidal chemical. Although the production and toxic effects of m-tyrosine are known, its microbial degradation has not been documented yet. A soil microcosm study showed efficient degradation of m-tyrosine by the inhabitant microorganisms. A bacterial strain designated SSC5, that was able to utilize m-tyrosine as the sole source of carbon, nitrogen, and energy, was isolated from the soil microcosm and was characterized as Bacillus aquimaris. Analytical methods such as HPLC, GC-MS, and 1H-NMR performed on the resting cell samples identified the formation of 3-hydroxyphenylpyruvate (3-OH-PPA), 3-hydroxyphenylacetate (3-OH-PhAc), and homogentisate (HMG) as major intermediates in the m-tyrosine degradation pathway. Enzymatic assays carried out on cell-free lysates of m-tyrosine-induced cells confirmed transamination reaction as the first step of m-tyrosine degradation. The intermediate 3-OH-PhAc thus obtained was further funneled into the HMG central pathway as revealed by a hydroxylase enzyme assay. Subsequent degradation of HMG occurred by ring cleavage catalyzed by the enzyme homogentisate 1, 2-dioxygenase. This study has significant implications in terms of understanding the environmental fate of m-tyrosine as well as regulation of its phytotoxic effect by soil microorganisms.

show abstract

Cloning of a Novel 6-Chloronicotinic Acid Chlorohydrolase from the Newly Isolated 6-Chloronicotinic Acid Mineralizing Bradyrhizobiaceae Strain SG-6C

Cited by 21 publications

References 37 publications

Metabolism of 2-Chloro-4-Nitroaniline via Novel Aerobic Degradation Pathway by Rhodococcus sp. Strain MB-P1

Metabolism of 2-Chloro-4-Nitroaniline via Novel Aerobic Degradation Pathway by Rhodococcus sp. Strain MB-P1

Aerobic Degradation of N-Methyl-4-Nitroaniline (MNA) by Pseudomonas sp. Strain FK357 Isolated from Soil

Biodegradation of the Allelopathic Chemical m-Tyrosine by Bacillus aquimaris SSC5 Involves the Homogentisate Central Pathway

Contact Info

Product

Resources

About