Transcriptome differences between Cupriavidus necator NH9 grown with 3-chlorobenzoate and that grown with benzoate

BackgroundAromatic compounds derived from human activities are often released into the environment. Many of them, especially halogenated aromatics, are persistent in nature and pose threats to organisms. Therefore, the microbial degradation of these compounds has been studied intensively. Our laboratory has studied the expression of genes in Cupriavidus necator NH9 involved in the degradation of 3-chlorobenzoate (3-CB), a model compound for studies on bacterial degradation of chlorinated aromatic compounds. In this study aimed at exploring how this bacterium has adapted to the utilization of chlorinated aromatic compounds, we performed RNA-seq analysis of NH9 cells cultured with 3-CB, benzoate (BA), or citric acid (CA). The purpose of these analyses was to identify differentially expressed genes encoding products with various biological functions involved in the degradation of 3-CB and BA.ResultsDifferential expression analysis confirmed strong induction of genes encoding enzymes in degradation pathways of 3-CB and BA, including benABCD (more than 256-fold compared with CA) encoding benzoate 1,2-dioxygenase involved in initial hydroxylation of both 3-CB and BA, and cbnABCD (more than 200-fold compared with BA and CA) encoding enzymes of chlorocatechol ortho-cleavage pathway. Four genes encoding major facilitator superfamily transporters were specifically induced by 3-CB or BA, and one cluster of genes encoding components of the ATP-binding cassette transporter system was significantly induced by 3-CB. Stress response genes encoding chaperones, proteases, the phosphate transporter PstBACS, and superoxide oxidase were upregulated in response to 3-CB and/or BA. Gene Ontology enrichment analysis revealed that genes encoding dioxygenases were upregulated by both 3-CB and BA. Intriguingly, the “cell motility,” “signal transduction,” and “chemotaxis” terms were significantly upregulated by BA compared with 3-CB. Consistent with this, in semi-solid agar plate assays, NH9 cells showed stronger chemotaxis to BA than to 3-CB.ConclusionsOur results showed that the chemotaxis behavior of NH9 differs between 3-CB and BA. We inferred that NH9 has not fully adapted to the utilization of chlorinated benzoate, unlike its analogous aromatic compound BA, in nature.

Transcriptome differences between Cupriavidus necator NH9 grown with 3-chlorobenzoate and that grown with benzoate

Background Aromatic compounds derived from human activities are often released into the environment. Many of them, especially halogenated aromatics, are persistent in nature and pose threats to organisms. Therefore, the microbial degradation of these compounds has been studied intensively. Our laboratory has studied the expression of genes in Cupriavidus necator NH9 involved in the degradation of 3-chlorobenzoate (3-CB), a model compound for studies on bacterial degradation of chlorinated aromatic compounds. In this study aimed at exploring how this bacterium has adapted to the utilization of chlorinated aromatic compounds, we performed RNA-seq analysis of NH9 cells cultured with 3-CB, benzoate (BA), or citric acid (CA). The purpose of these analyses was to identify differentially expressed genes encoding products with various biological functions involved in the degradation of 3-CB and BA. Results Differential expression analysis confirmed strong induction of genes encoding enzymes in degradation pathways of 3-CB and BA, including benABCD (more than 256-fold compared with CA) encoding benzoate 1,2-dioxygenase involved in initial hydroxylation of both 3-CB and BA, and cbnABCD (more than 200-fold compared with BA and CA) encoding enzymes of chlorocatechol ortho -cleavage pathway. Four genes encoding major facilitator superfamily transporters were specifically induced by 3-CB or BA, and one cluster of genes encoding components of the ATP-binding cassette transporter system was significantly induced by 3-CB. Stress response genes encoding chaperones, proteases, the phosphate transporter PstBACS, and superoxide oxidase were upregulated in response to 3-CB and/or BA. Gene Ontology enrichment analysis revealed that genes encoding dioxygenases were upregulated by both 3-CB and BA. Intriguingly, the “cell motility,” “signal transduction,” and “chemotaxis” terms were significantly upregulated by BA compared with 3-CB. Consistent with this, in semi-solid agar plate assays, NH9 cells showed stronger chemotaxis to BA than to 3-CB. Conclusions Our results showed that the chemotaxis behavior of NH9 differs between 3-CB and BA. We inferred that NH9 has not fully adapted to the utilization of chlorinated benzoate, unlike its analogous aromatic compound BA, in nature.

Hydrodechlorination of Different Chloroaromatic Compounds at Room Temperature and Ambient Pressure—Differences in Reactivity of Cu- and Ni-Based Al Alloys in an Alkaline Aqueous Solution

It is well known that the hydrodechlorination (HDC) of chlorinated aromatic contaminants in aqueous effluents enables a significant increase in biodegradability. HDC consumes a low quantity of reactants producing corresponding non-chlorinated and much more biodegradable organic compounds. Two commonly used precious metals free Al alloys (Raney Al-Ni and Devarda’s Al-Cu-Zn) were compared in reductive action in an alkaline aqueous solution. Raney Al-Ni alloy was examined as a universal and extremely effective HDC agent in a diluted aqueous NaOH solution. The robustness of Raney Al-Ni activity is illustrated in the case of HDC of polychlorinated aromatic compounds mixture in actual waste water. In contrast, Devarda’s Al-Cu-Zn alloy was approved as much less active for HDC of the tested chlorinated aromatic compounds, but with a surprisingly high selectivity on cleavage of C-Cl bonds in the meta and sometimes the ortho position in chlorinated aniline and sometimes chlorinated phenol structures. The reaction of both tested alloys with chlorinated aromatic compounds in the aqueous NaOH solution is accompanied by dissolution of aluminum. Dissolved Al in the alkaline HDC reaction mixture is very useful for subsequent treatment of HDC products by coagulation and flocculation of Al(OH)3 caused by simple neutralization of the alkaline aqueous phase after the HDC reaction.

Transcriptome differences between Cupriavidus necator NH9 grown with 3-chlorobenzoate and that grown with benzoate

Background Aromatic compounds derived from human activities are often released into the environment. Many of them, especially halogenated aromatics, are persistent in nature and pose threats to organisms. Therefore, the microbial degradation of these compounds has been studied intensively. Our laboratory has studied the expression of genes in Cupriavidus necator NH9 involved in the degradation of 3-chlorobenzoate (3-CB), a model compound for studies on bacterial degradation of chlorinated aromatic compounds. In this study aimed at exploring how this bacterium has adapted to the utilization of chlorinated aromatic compounds, we performed RNA-seq analysis of NH9 cells cultured with 3-CB, benzoate (BA), or citric acid. The purpose of these analyses was to identify differentially expressed genes encoding products with various biological functions involved in the degradation of 3-CB and BA. Results Differential expression analysis confirmed strong induction of genes encoding enzymes in degradation pathways of 3-CB and BA (benABCD, cbnABCD, catA, catB, catDC, pcaIJF, and boxABCD). Genes involved in the degradation of 3-hydroxybenzoate and anthranilate were upregulated by 3-CB but not by BA, suggesting that transcriptional regulators of these degradative genes recognized 3-CB (or its intermediate metabolite) as an inducer. Four genes encoding MFS transporters were specifically induced by 3-CB or BA, and one cluster of genes encoding components of the ABC transporter system was significantly induced by 3-CB. Stress response genes encoding chaperones, proteases, the phosphate transporter PstBACS, and superoxide oxidase were upregulated in response to 3-CB and/or BA. Gene Ontology enrichment analysis revealed that genes encoding dioxygenases were upregulated by both 3-CB and BA. Intriguingly, the “cell motility,” “signal transduction,” and “chemotaxis” terms were significantly upregulated by BA compared with 3-CB. Consistent with this, in semi-solid agar plate assays, NH9 cells showed stronger chemotaxis to BA than to 3-CB. Conclusions Our results showed that the chemotaxis behavior of NH9 differs between 3-CB and BA. We inferred that NH9 has not fully adapted to the utilization of chlorinated benzoate, unlike its analogous aromatic compound BA, in nature.

A simple and effective approach for catalytic reductive dechlorination of aromatic compounds

An efficient process for the preparation of 2(3),9(10),16(17),23(24)-octa(n-hexyl)cobalt(II)phthalocyanine, ((n-hexyl)8CoPc) (2) was described. The novel cobalt(II)phthalocyanine was characterized by spectroscopic methods. It was employed as a catalyst for the room temperature reductive dechlorination of chlorinated aromatic compounds (CACs). The results were showed that the CACs were completely dechlorinated within 110–120 min.