scholarly journals Steroid Degradation in Comamonas testosteroni TA441: Identification of the Entire β-Oxidation Cycle of the Cleaved B Ring

2019 ◽  
Vol 85 (20) ◽  
Author(s):  
Masae Horinouchi ◽  
Hiroyuki Koshino ◽  
Michal Malon ◽  
Hiroshi Hirota ◽  
Toshiaki Hayashi
Keyword(s):  
Gene Clusters ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Ring Cleavage ◽  
Comamonas Testosteroni ◽  
Content Type ◽  
Coa Transferase ◽  
Degrading Bacteria ◽  
Globally Distributed

ABSTRACT Comamonas testosteroni TA441 degrades steroids via aromatization of the A ring, followed by degradation of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid, mainly by β-oxidation. In this study, we revealed that 7β,9α-dihydroxy-17-oxo-1,2,3,4,10,19-hexanorandrostanoic acid-coenzyme A (CoA) ester is dehydrogenated by (3S)-3-hydroxylacyl CoA-dehydrogenase, encoded by scdE (ORF27), and then the resultant 9α-hydroxy-7,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid-CoA ester is converted by 3-ketoacyl-CoA transferase, encoded by scdF (ORF23). With these results, the whole cycle of β-oxidation on the side chain at C-8 of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid is clarified; 9-hydroxy-17-oxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid-CoA ester is dehydrogenated at C-6 by ScdC1C2, followed by hydration by ScdD. 7β,9α-Dihydroxy-17-oxo-1,2,3,4,10,19-hexanorandrostanoic acid-CoA ester then is dehydrogenated by ScdE to be converted to 9α-hydroxy-17-oxo-1,2,3,4,5,6,10,19-octanorandrostan-7-oic acid-CoA ester and acetyl-CoA by ScdF. ScdF is an ortholog of FadA6 in Mycobacterium tuberculosis H37Rv, which was reported as a 3-ketoacyl-CoA transferase involved in C ring cleavage. We also obtained results suggesting that ScdF is also involved in C ring cleavage, but further investigation is required for confirmation. ORF25 and ORF26, located between scdF and scdE, encode enzymes belonging to the amidase superfamily. Disrupting either ORF25 or ORF26 did not affect steroid degradation. Among the bacteria having gene clusters similar to those of tesB to tesR, some have both ORF25- and ORF26-like proteins or only an ORF26-like protein, but others do not have either ORF25- or ORF26-like proteins. ORF25 and ORF26 are not crucial for steroid degradation, yet they might provide clues to elucidate the evolution of bacterial steroid degradation clusters. IMPORTANCE Studies on bacterial steroid degradation were initiated more than 50 years ago primarily to obtain materials for steroid drugs. Steroid-degrading bacteria are globally distributed, and the role of bacterial steroid degradation in the environment as well as in relation to human health is attracting attention. The overall aerobic degradation of the four basic steroidal rings has been proposed; however, there is still much to be revealed to understand the complete degradation pathway. This study aims to uncover the whole steroid degradation process in Comamonas testosteroni TA441 as a model of steroid-degrading bacteria. C. testosteroni is one of the most studied representative steroid-degrading bacteria and is suitable for exploring the degradation pathway, because the involvement of degradation-related genes can be determined by gene disruption. Here, we elucidated the entire β-oxidation cycle of the cleaved B ring. This cycle is essential for the following C and D ring cleavage.

scholarly journals Steroid Degradation in Comamonas testosteroni TA441: Identification of Metabolites and the Genes Involved in the Reactions Necessary before D-Ring Cleavage

2018 ◽  
Vol 84 (22) ◽  
Author(s):  
Masae Horinouchi ◽  
Hiroyuki Koshino ◽  
Michal Malon ◽  
Hiroshi Hirota ◽  
Toshiaki Hayashi
Keyword(s):  
Wastewater Treatment Plants ◽  
Degradation Process ◽  
Ring Cleavage ◽  
Comamonas Testosteroni ◽  
Content Type ◽  
Oxidative Reactions ◽  
Degrading Bacteria ◽  
Steroid Drugs ◽  
Globally Distributed

ABSTRACT Bacterial steroid degradation has been studied mainly with Rhodococcus equi (Nocardia restrictus) and Comamonas testosteroni as representative steroid degradation bacteria for more than 50 years. The primary purpose was to obtain materials for steroid drugs, but recent studies showed that many genera of bacteria (Mycobacterium, Rhodococcus, Pseudomonas, etc.) degrade steroids and that steroid-degrading bacteria are globally distributed and found particularly in wastewater treatment plants, the soil, plant rhizospheres, and the marine environment. The role of bacterial steroid degradation in the environment is, however, yet to be revealed. To uncover the whole steroid degradation process in a representative steroid-degrading bacterium, C. testosteroni, to provide basic information for further studies on the role of bacterial steroid degradation, we elucidated the two indispensable oxidative reactions and hydration before D-ring cleavage in C. testosteroni TA441. In bacterial oxidative steroid degradation, A- and B-rings of steroids are cleaved to produce 2-hydroxyhexa-2,4-dienoic acid and 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid. The latter compound was revealed to be degraded to the coenzyme A (CoA) ester of 9α-hydroxy-17-oxo-1,2,3,4,5,6,10,19-octanorandrostan-7-oic acid, which is converted to the CoA ester of 9,17-dioxo-1,2,3,4,5,6,10,19-octanorandrostan-7-oic acid by ORF31-encoded hydroxylacyl dehydrogenase (ScdG), followed by conversion to the CoA ester of 9,17-dioxo-1,2,3,4,5,6,10,19-octanorandrost-8(14)-en-7-oic acid by ORF4-encoded acyl-CoA dehydrogenase (ScdK). Then, a water molecule is added by the ORF5-encoded enoyl-CoA hydratase (ScdY), which leads to the cleavage of the D-ring. The conversion by ScdG is presumed to be a reversible reaction. The elucidated pathway in C. testosteroni TA441 is different from the corresponding pathways in Mycobacterium tuberculosis H37Rv. IMPORTANCE Studies on representative steroid degradation bacteria Rhodococcus equi (Nocardia restrictus) and Comamonas testosteroni were initiated more than 50 years ago primarily to obtain materials for steroid drugs. A recent study showed that steroid-degrading bacteria are globally distributed and found particularly in wastewater treatment plants, the soil, plant rhizospheres, and the marine environment, but the role of bacterial steroid degradation in the environment is yet to be revealed. This study aimed to uncover the whole steroid degradation process in C. testosteroni TA441, in which major enzymes for steroidal A- and B-ring cleavage were elucidated, to provide basic information for further studies on bacterial steroid degradation. C. testosteroni is suitable for exploring the degradation pathway because the involvement of degradation-related genes can be determined by gene disruption. We elucidated the two indispensable oxidative reactions and hydration before D-ring cleavage, which appeared to differ from those present in Mycobacterium tuberculosis H37Rv.

scholarly journals Identification of the CoA-ester intermediates and genes involved in the cleavage and degradation of the steroidal C-ring by Comamonas testosteroni TA441

2021 ◽  
Author(s):  
Masae Horinouchi ◽  
Toshiaki Hayashi
Keyword(s):  
Degradation Process ◽  
Intermediate Compound ◽  
Degradation Pathway ◽  
Hydroxyl Group ◽  
Ring Cleavage ◽  
Comamonas Testosteroni ◽  
Dioic Acid ◽  
Coa Transferase ◽  
Degrading Bacteria ◽  
Globally Distributed

Comamonas testosteroni TA441 degrades steroids aerobically via aromatization of the A-ring accompanied by B-ring cleavage, followed by D- and C-ring cleavage. We previously revealed major enzymes and intermediate compounds in A,B-ring cleavage, β-oxidation cycle of the cleaved B-ring, and partial C,D-ring cleavage process. Here, we elucidated the C-ring cleavage and the β-oxidation cycle that follows. ScdL1L2, a 3-ketoacid Coenzyme A (CoA) transferase which belongs to the SugarP_isomerase superfamily, was thought to cleave the C-ring of 9-oxo-1,2,3,4,5,6,10,19-octanor-13,17-secoandrost-8(14)-ene-7,17-dioic acid-CoA ester, the key intermediate compound in the degradation of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid (3aα- H -4α [3′-propionic acid]-7aβ-methylhexahydro-1,5-indanedione; HIP)-CoA ester in the previous study; however, this study suggested that ScdL1L2 is the isomerase of the derivative with a hydroxyl group at C-14 which cleaves C ring. The subsequent ring-cleaved product was indicated to be converted to 4-methyl-5-oxo-octane-1,8-dioic acid-CoA ester mainly by ORF33-encoded CoA-transferase (named ScdJ), followed by dehydrogenation by ORF21 and 22-encoded acyl-CoA dehydrogenase (named ScdM1M2). Then a water molecule is added by ScdN for further degradation by β-oxidation. ScdN is considered to catalyze the last reaction in C,D-ring degradation by the enzymes encoded in the steroid degradation gene cluster tesB to tesR . IMPORTANCE Studies on bacterial steroid degradation were initiated more than 50 years ago primarily to obtain materials for steroid drugs. Steroid-degrading bacteria are globally distributed, and the role of bacterial steroid degradation in the environment as well as in human is attracting attention. The overall degradation of steroidal four rings is proposed, however there are still much to be revealed to understand the complete degradation pathway. This study aims to uncover the whole steroid degradation process in C. testosteroni , which is one of the most studied representative steroid degrading bacteria and is suitable for exploring the degradation pathway because the involvement of degradation-related genes can be determined by gene disruption.

scholarly journals Proteogenomic Elucidation of the Initial Steps in the Benzene Degradation Pathway of a Novel Halophile, Arhodomonas sp. Strain Rozel, Isolated from a Hypersaline Environment

2012 ◽  
Vol 78 (20) ◽  
pp. 7309-7316 ◽  
Author(s):  
Sonal Dalvi ◽  
Sei Azetsu ◽  
Marianna A. Patrauchan ◽  
Deniz F. Aktas ◽  
Babu Z. Fathepure
Keyword(s):  
Mass Spectrometry ◽  
Tricarboxylic Acid Cycle ◽  
Draft Genome ◽  
Degradation Pathway ◽  
Phenol Hydroxylase ◽  
Ring Cleavage ◽  
Content Type ◽  
Benzene Degradation ◽  
Chromatography Mass Spectrometry

ABSTRACTLately, there has been a special interest in understanding the role of halophilic and halotolerant organisms for their ability to degrade hydrocarbons. The focus of this study was to investigate the genes and enzymes involved in the initial steps of the benzene degradation pathway in halophiles. The extremely halophilic bacteriaArhodomonassp. strain Seminole andArhodomonassp. strain Rozel, which degrade benzene and toluene as the sole carbon source at high salinity (0.5 to 4 M NaCl), were isolated from enrichments developed from contaminated hypersaline environments. To obtain insights into the physiology of this novel group of organisms, a draft genome sequence of the Seminole strain was obtained. A cluster of 13 genes predicted to be functional in the hydrocarbon degradation pathway was identified from the sequence. Two-dimensional (2D) gel electrophoresis and liquid chromatography-mass spectrometry were used to corroborate the role of the predicted open reading frames (ORFs). ORFs 1080 and 1082 were identified as components of a multicomponent phenol hydroxylase complex, and ORF 1086 was identified as catechol 2,3-dioxygenase (2,3-CAT). Based on this analysis, it was hypothesized that benzene is converted to phenol and then to catechol by phenol hydroxylase components. The resulting catechol undergoes ring cleavage via the meta pathway by 2,3-CAT to form 2-hydroxymuconic semialdehyde, which enters the tricarboxylic acid cycle. To substantiate these findings, the Rozel strain was grown on deuterated benzene, and gas chromatography-mass spectrometry detected deuterated phenol as the initial intermediate of benzene degradation. These studies establish the initial steps of the benzene degradation pathway in halophiles.

scholarly journals Role of IncP-1β Plasmids pWDL7::rfpand pNB8c in Chloroaniline Catabolism as Determined by Genomic and Functional Analyses

2011 ◽  
Vol 78 (3) ◽  
pp. 828-838 ◽  
Author(s):  
J. E. Król ◽  
J. T. Penrod ◽  
H. McCaslin ◽  
L. M. Rogers ◽  
H. Yano ◽  
...  
Keyword(s):  
Single Copy ◽  
Degradation Pathway ◽  
Bacterial Degradation ◽  
Ring Cleavage ◽  
Close Relative ◽  
Broad Host Range ◽  
Content Type ◽  
Aromatic Ring Cleavage ◽  
Functional Analyses

ABSTRACTBroad-host-range catabolic plasmids play an important role in bacterial degradation of man-made compounds. To gain insight into the role of these plasmids in chloroaniline degradation, we determined the first complete nucleotide sequences of an IncP-1 chloroaniline degradation plasmid, pWDL7::rfpand its close relative pNB8c, as well as the expression pattern, function, and bioaugmentation potential of the putative 3-chloroaniline (3-CA) oxidation genes. Based on phylogenetic analysis of backbone proteins, both plasmids are members of a distinct clade within the IncP-1β subgroup. The plasmids are almost identical, but whereas pWDL7::rfpcarries a duplicate inverted catabolic transposon, Tn6063, containing a putative 3-CA oxidation gene cluster,dcaQTA1A2BR, pNB8c contains only a single copy of the transposon. No genes for an aromatic ring cleavage pathway were detected on either plasmid, suggesting that only the upper 3-CA degradation pathway was present. ThedcaA1A2Bgene products expressed from a high-copy-number vector were shown to convert 3-CA to 4-chlorocatechol inEscherichia coli. Slight differences in thedcapromoter region between the plasmids and lack of induction of transcription of the pNB8cdcagenes by 3-CA may explain previous findings that pNB8C does not confer 3-CA transformation. Bioaugmentation of activated sludge with pWDL7::rfpaccelerated removal of 3-CA, but only in the presence of an additional carbon source. Successful bioaugmentation requires complementation of the upper pathway genes with chlorocatechol cleavage genes in indigenous bacteria. The genome sequences of these plasmids thus help explain the molecular basis of their catabolic activities.

scholarly journals Biodegradation of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine and Its Mononitroso Derivative Hexahydro-1-Nitroso-3,5-Dinitro-1,3,5-Triazine by Klebsiella pneumoniae Strain SCZ-1 Isolated from an Anaerobic Sludge

2002 ◽  
Vol 68 (11) ◽  
pp. 5336-5341 ◽  
Author(s):  
Jian-Shen Zhao ◽  
Annamaria Halasz ◽  
Louise Paquet ◽  
Chantale Beaulieu ◽  
Jalal Hawari
Keyword(s):  
Klebsiella Pneumoniae ◽  
Removal Rate ◽  
Dry Weight ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Ring Cleavage ◽  
Anaerobic Sludge ◽  
Initial Reaction ◽  
Total N

ABSTRACT In previous work, we found that an anaerobic sludge efficiently degraded hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), but the role of isolates in the degradation process was unknown. Recently, we isolated a facultatively anaerobic bacterium, identified as Klebsiella pneumoniae strain SCZ-1, using MIDI and the 16S rRNA method from this sludge and employed it to degrade RDX. Strain SCZ-1 degraded RDX to formaldehyde (HCHO), methanol (CH3OH) (12% of total C), carbon dioxide (CO2) (72% of total C), and nitrous oxide (N2O) (60% of total N) through intermediary formation of methylenedinitramine (O2NNHCH2NHNO2). Likewise, hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) was degraded to HCHO, CH3OH, and N2O (16.5%) with a removal rate (0.39 μmol · h−1 · g [dry weight] of cells−1) similar to that of RDX (0.41 μmol · h−1 · g [dry weight] of cells−1) (biomass, 0.91 g [dry weight] of cells · liter−1). These findings suggested the possible involvement of a common initial reaction, possibly denitration, followed by ring cleavage and decomposition in water. The trace amounts of MNX detected during RDX degradation and the trace amounts of hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine detected during MNX degradation suggested that another minor degradation pathway was also present that reduced —NO2 groups to the corresponding —NO groups.

scholarly journals Estrogen Degraders and Estrogen Degradation Pathway Identified in an Activated Sludge

2018 ◽  
Vol 84 (10) ◽  
Author(s):  
Yi-Lung Chen ◽  
Han-Yi Fu ◽  
Tzong-Huei Lee ◽  
Chao-Jen Shih ◽  
Lina Huang ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment Plant ◽  
Degradation Pathway ◽  
Bacterial Degradation ◽  
Ring Cleavage ◽  
Main Process ◽  
Content Type ◽  
Degrading Bacteria

ABSTRACTThe environmental release and fate of estrogens are becoming an increasing public concern. Bacterial degradation has been considered the main process for eliminating estrogens from wastewater treatment plants. Various bacterial isolates are reportedly capable of aerobic estrogen degradation, and several estrogen degradation pathways have been proposed in proteobacteria and actinobacteria. However, the ecophysiological relevance of estrogen-degrading bacteria in the environment is unclear. In this study, we investigated the estrogen degradation pathway and corresponding degraders in activated sludge collected from the Dihua Sewage Treatment Plant, Taipei, Taiwan. Cultivation-dependent and cultivation-independent methods were used to assess estrogen biodegradation in the collected activated sludge. Estrogen metabolite profile analysis revealed the production of pyridinestrone acid and two A/B-ring cleavage products in activated sludge incubated with estrone (1 mM), which are characteristic of the 4,5-secopathway. PCR-based functional assays detected sequences closely related to alphaproteobacterialoecC, a key gene of the 4,5-secopathway. Metagenomic analysis suggested thatNovosphingobiumspp. are major estrogen degraders in estrone-amended activated sludge.Novosphingobiumsp. strain SLCC, an estrone-degrading alphaproteobacterium, was isolated from the examined activated sludge. The general physiology and metabolism of this strain were characterized. Pyridinestrone acid and the A/B-ring cleavage products were detected in estrone-grown strain SLCC cultures. The production of pyridinestrone acid was also observed during the aerobic incubation of strain SLCC with 3.7 nM (1 μg/liter) estrone. This concentration is close to that detected in many natural and engineered aquatic ecosystems. The presented data suggest the ecophysiological relevance ofNovosphingobiumspp. in activated sludge.IMPORTANCEEstrogens, which persistently contaminate surface water worldwide, have been classified as endocrine disruptors and human carcinogens. We contribute new knowledge on the major estrogen biodegradation pathway and estrogen degraders in wastewater treatment plants. This study considerably advances the understanding of environmental estrogen biodegradation, which is instrumental for the efficient elimination of these hazardous pollutants. Moreover, this study substantially improves the understanding of microbial estrogen degradation in the environment.

scholarly journals Novel Pathway for the Degradation of 2-Chloro-4-Nitrobenzoic Acid by Acinetobacter sp. Strain RKJ12

2011 ◽  
Vol 77 (18) ◽  
pp. 6606-6613 ◽  
Author(s):  
Dhan Prakash ◽  
Ravi Kumar ◽  
R. K. Jain ◽  
B. N. Tiwary
Keyword(s):  
Salicylic Acid ◽  
Tricarboxylic Acid Cycle ◽  
Sole Source ◽  
Degradation Pathway ◽  
Ring Cleavage ◽  
Muconic Acid ◽  
Content Type ◽  
Nitrobenzoic Acid ◽  
Catabolic Genes ◽  
Catechol 1,2 Dioxygenase

ABSTRACTThe organismAcinetobactersp. RKJ12 is capable of utilizing 2-chloro-4-nitrobenzoic acid (2C4NBA) as a sole source of carbon, nitrogen, and energy. In the degradation of 2C4NBA by strain RKJ12, various metabolites were isolated and identified by a combination of chromatographic, spectroscopic, and enzymatic activities, revealing a novel assimilation pathway involving both oxidative and reductive catabolic mechanisms. The metabolism of 2C4NBA was initiated by oxidativeorthodehalogenation, leading to the formation of 2-hydroxy-4-nitrobenzoic acid (2H4NBA), which subsequently was metabolized into 2,4-dihydroxybenzoic acid (2,4-DHBA) by a mono-oxygenase with the concomitant release of chloride and nitrite ions. Stoichiometric analysis indicated the consumption of 1 mol O2per conversion of 2C4NBA to 2,4-DHBA, ruling out the possibility of two oxidative reactions. Experiments with labeled H218O and18O2indicated the involvement of mono-oxygenase-catalyzed initial hydrolytic dechlorination and oxidative denitration mechanisms. The further degradation of 2,4-DHBA then proceeds via reductive dehydroxylation involving the formation of salicylic acid. In the lower pathway, the organism transformed salicylic acid into catechol, which was mineralized by theorthoring cleavage catechol-1,2-dioxygenase tocis, cis-muconic acid, ultimately forming tricarboxylic acid cycle intermediates. Furthermore, the studies carried out on a 2C4NBA−derivative and a 2C4NBA+transconjugant demonstrated that the catabolic genes for the 2C4NBA degradation pathway possibly reside on the ∼55-kb transmissible plasmid present in RKJ12.

scholarly journals The Role of Chaperone-Mediated Autophagy in Hepatitis C Virus-Induced Pathogenesis

2021 ◽  
Vol 11 ◽  
Author(s):  
Chieko Matsui ◽  
Putu Yuliandari ◽  
Lin Deng ◽  
Takayuki Abe ◽  
Ikuo Shoji
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Hepatocyte Nuclear Factor ◽  
Selective Degradation ◽  
Substrate Protein ◽  
Hepatocyte Nuclear Factor 1Α ◽  
Chaperone Mediated Autophagy

Lysosome incorporate and degrade proteins in a process known as autophagy. There are three types of autophagy; macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). Although autophagy is considered a nonselective degradation process, CMA is known as a selective degradation pathway. All proteins internalized in the lysosome via CMA contain a pentapeptide KFERQ-motif, also known as a CMA-targeting motif, which is necessary for selectivity. CMA directly delivers a substrate protein into the lysosome lumen using the cytosolic chaperone HSC70 and the lysosomal receptor LAMP-2A for degradation. Hepatitis C virus (HCV) NS5A protein interacts with hepatocyte-nuclear factor 1α (HNF-1α) together with HSC70 and promotes the lysosomal degradation of HNF-1α via CMA, resulting in HCV-induced pathogenesis. HCV NS5A promotes recruitment of HSC70 to the substrate protein HNF-1α. HCV NS5A plays a crucial role in HCV-induced CMA. Further investigations of HCV NS5A-interacting proteins containing CMA-targeting motifs may help to elucidate HCV-induced pathogenesis.

scholarly journals Chitin Heterodisaccharide, Released from Chitin by Chitinase and Chitin Oligosaccharide Deacetylase, Enhances the Chitin-Metabolizing Ability of Vibrio parahaemolyticus

2019 ◽  
Vol 201 (20) ◽  
Author(s):  
Takako Hirano ◽  
Manabu Okubo ◽  
Hironobu Tsuda ◽  
Masahiro Yokoyama ◽  
Wataru Hakamata ◽  
...  
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Pcr Analysis ◽  
Content Type ◽  
Chitin Degradation ◽  
Expression Of Genes ◽  
Peptide Mass ◽  
Degrading Bacteria ◽  
Genes Encoding ◽  
Chitinase Production

ABSTRACT Vibrio parahaemolyticus RIMD2210633 secretes both chitinase and chitin oligosaccharide deacetylase and produces β-N-acetyl-d-glucosaminyl-(1,4)-d-glucosamine (GlcNAc-GlcN) from chitin. Previously, we reported that GlcNAc-GlcN induces chitinase production by several strains of Vibrio harboring chitin oligosaccharide deacetylase genes (T. Hirano, K. Kadokura, T. Ikegami, Y. Shigeta, et al., Glycobiology 19:1046–1053, 2009). The metabolism of chitin by Vibrio was speculated on the basis of the findings of previous studies, and the role of chitin oligosaccharide produced from chitin has been well studied. However, the role of GlcNAc-GlcN in the Vibrio chitin degradation system, with the exception of the above-mentioned function as an inducer of chitinase production, remains unclear. N,N′-Diacetylchitobiose, a homodisaccharide produced from chitin, is known to induce the expression of genes encoding several proteins involved in chitin metabolism in Vibrio strains (K. L. Meibom, X. B. Li, A. Nielsen, C. Wu, et al., Proc Natl Acad Sci U S A 101:2524–2529, 2004). We therefore hypothesized that GlcNAc-GlcN also affects the expression of enzymes involved in chitin metabolism in the same manner. In this study, we examined the induction of protein expression by several sugars released from chitin using peptide mass fingerprinting and confirmed the expression of genes encoding enzymes involved in chitin metabolism using real-time quantitative PCR analysis. We then confirmed that GlcNAc-GlcN induces the expression of genes encoding many soluble enzymes involved in chitin degradation in Vibrio parahaemolyticus. Here, we demonstrate that GlcNAc-GlcN enhances the chitin-metabolizing ability of V. parahaemolyticus. IMPORTANCE We demonstrate that β-N-acetyl-d-glucosaminyl-(1,4)-d-glucosamine (GlcNAc-GlcN) enhances the chitin-metabolizing ability of V. parahaemolyticus. Members of the genus Vibrio are chitin-degrading bacteria, and some species of this genus are associated with diseases affecting fish and animals, including humans (F. L. Thompson, T. Iida, and J. Swings, Microbiol Mol Biol Rev 68:403–431, 2004; M. Y. Ina-Salwany, N. Al-Saari, A. Mohamad, F.-A. Mursidi, et al., J Aquat Anim Health 31:3–22, 2019). Studies on Vibrio are considered important, as they may facilitate the development of solutions related to health, food, and aquaculture problems attributed to this genus. This report enhances the current understanding of chitin degradation by Vibrio bacteria.

scholarly journals Involvement of Two Latex-Clearing Proteins during Rubber Degradation and Insights into the Subsequent Degradation Pathway Revealed by the Genome Sequence of Gordonia polyisoprenivorans Strain VH2

2012 ◽  
Vol 78 (8) ◽  
pp. 2874-2887 ◽  
Author(s):  
Sebastian Hiessl ◽  
Jörg Schuldes ◽  
Andrea Thürmer ◽  
Tobias Halbsguth ◽  
Daniel Bröker ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Degradation Pathway ◽  
Current Data ◽  
Circular Chromosome ◽  
Content Type ◽  
Microbial Utilization ◽  
Degrading Bacteria ◽  
Key Enzyme ◽  
Gordonia Polyisoprenivorans ◽  
Rubber Degradation

ABSTRACTThe increasing production of synthetic and natural poly(cis-1,4-isoprene) rubber leads to huge challenges in waste management. Only a few bacteria are known to degrade rubber, and little is known about the mechanism of microbial rubber degradation. The genome ofGordonia polyisoprenivoransstrain VH2, which is one of the most effective rubber-degrading bacteria, was sequenced and annotated to elucidate the degradation pathway and other features of this actinomycete. The genome consists of a circular chromosome of 5,669,805 bp and a circular plasmid of 174,494 bp with average GC contents of 67.0% and 65.7%, respectively. It contains 5,110 putative protein-coding sequences, including many candidate genes responsible for rubber degradation and other biotechnically relevant pathways. Furthermore, we detected two homologues of a latex-clearing protein, which is supposed to be a key enzyme in rubber degradation. The deletion of these two genes for the first time revealed clear evidence that latex-clearing protein is essential for the microbial utilization of rubber. Based on the genome sequence, we predict a pathway for the microbial degradation of rubber which is supported by previous and current data on transposon mutagenesis, deletion mutants, applied comparative genomics, and literature search.

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