Microcystin-LR biodegradation by Sphingopyxis sp. USTB-05

Xiao, Chengbin; Yan, Hai; Wang, Junfeng; Wei, Wei; Ning, Jun; Pan, Gang

doi:10.1007/s11783-010-0261-7

Cited by 26 publications

(20 citation statements)

References 31 publications

(66 reference statements)

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“…Finally the fourth enzyme peptidase cleaved the peptide bond of Tyr-Masp in the linear tripeptide of Tyr-Masp-Arg, and Tyr ( m/z 181) (product D) and dipeptide (Masp-Arg) ( m/z 268) were produced ( Fig 8 ). Generally, the biodegradation pathway of MC-YR was very similar to that of MC-RR and MC-LR in the first three steps we have reported previously [ 18 , 19 ], [ 28 , 29 ]. Here we firstly provided direct evidence that the tripeptide of Tyr-Masp-Arg could also be further biodegraded, and Tyr was produced as a biodegradation product of MC-YR (Fig 3 and 8 ).…”

Section: Discussionsupporting

confidence: 79%

“…It was found that Sphingopyxis sp. USTB-05 possessed at least three enzymes involved in biodegradation of MC-LR and MC-RR, and three biodegradation genes have been firstly cloned and expressed [ 18 , 19 ], [ 28 , 29 ]. Compared with MC-RR and MC-LR, MC-YR is more complicated in structure containing a benzene ring of Tyr, which could also be rapidly biodegraded by CEs of Sphingopyxis sp.…”

Section: Discussionmentioning

confidence: 99%

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Pathway for Biodegrading Microcystin-YR by Sphingopyxis sp. USTB-05

Wang

et al. 2015

PLoS ONE

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Harmful cyanobacterial blooms in waters have become a global environmental problem, this mainly due to the production and release of various microalgal toxins, in which microcystins (MCs) are distributed widely. Here, we focused on the study of a typical form of microcystins called microcystin-YR (MC-YR). It was found that initial 14.8 mg/L of MC-YR could be completely eliminated within 10 hr by the crude enzymes (CEs) of Sphingopyxis sp. USTB-05, a promising bacterial strain we isolated and identified in our previous study. During the enzymatic biodegradation of MC-YR with time course, the peaks of two intermediate and two final products were observed on the profiles of HPLC at the wavelengths of 238 nm and 230 nm, respectively. Based on the analysis of m/z ratios of MC-YR and its four products by LC-MS/MS, we suggested that at least four enzymes were involved in the biodegradation of MC-YR by Sphingopyxis sp. USTB-05. The first enzyme microcystinase converted cyclic MC-YR to linear MC-YR as the first product. Then the second enzyme serine protease was found to cleave the target peptide bond between alanine (Ala) and tyrosine (Tyr) of linearized MC-YR, producing a tetrapeptide and a tripeptide as second products, which were Adda-Glu-Mdha-Ala and Tyr-Masp-Arg, respectively. Next, the third enzyme peptidase converted the tetrapeptide of Adda-Glu-Mdha-Ala to Adda. And the fourth enzyme cleaved the tripeptide of Tyr-Masp-Arg to produce Tyr and dipeptide (Masp-Arg), which has never been reported. These findings will help us better understand the biodegradation pathway of MC-YR by Sphingopyxis sp. USTB-05.

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Section: Discussionsupporting

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Pathway for Biodegrading Microcystin-YR by Sphingopyxis sp. USTB-05

Wang

et al. 2015

PLoS ONE

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“…Sphingopxyis sp. USTB-05 showed complete MCs (MC-LR, MC-RR and MC-YR) degradation with different intermediate products [30,[118][119][120][121]. These findings suggest that the enzymatic processes and degradation pathways may vary between MC variants and bacteria strains.…”

Section: Enzymatic Mechanisms Of Microcystins Biodegradationmentioning

confidence: 83%

A Mini Review on Microcystins and Bacterial Degradation

Massey

Yang

2020

Toxins

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Microcystins (MCs) classified as hepatotoxic and carcinogenic are the most commonly reported cyanobacterial toxins found in the environment. Microcystis sp. possessing a series of MC synthesis genes (mcyA-mcyJ) are well documented for their excessive abundance, numerous bloom occurrences and MC producing capacity. About 246 variants of MC which exert severe animal and human health hazards through the inhibition of protein phosphatases (PP1 and PP2A) have been characterized. To minimize and prevent MC health consequences, the World Health Organization proposed 1 µg/L MC guidelines for safe drinking water quality. Further the utilization of bacteria that represent a promising biological treatment approach to degrade and remove MC from water bodies without harming the environment has gained global attention. Thus the present review described toxic effects and bacterial degradation of MCs.

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“…A large array of MCs-degrading bacteria, both containing and lacking mlr genes, have been isolated from both water and sediment samples. Most of these strains belong to the phyla Proteobacteria (especially classes α- and β-Proteobacteria) [25,26,27], although strains from the phyla Actinobacteria and Firmicutes have also been reported [23,28]. …”

Section: Introductionmentioning

confidence: 99%

Presence or Absence of mlr Genes and Nutrient Concentrations Co-Determine the Microcystin Biodegradation Efficiency of a Natural Bacterial Community

Lezcano

Morón-López

Agha

et al. 2016

Toxins

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The microcystin biodegradation potential of a natural bacterial community coexisting with a toxic cyanobacterial bloom was investigated in a water reservoir from central Spain. The biodegradation capacity was confirmed in all samples during the bloom and an increase of mlrA gene copies was found with increasing microcystin concentrations. Among the 24 microcystin degrading strains isolated from the bacterial community, only 28% showed presence of mlrA gene, strongly supporting the existence and abundance of alternative microcystin degradation pathways in nature. In vitro degradation assays with both mlr+ and mlr− bacterial genotypes (with presence and absence of the complete mlr gene cluster, respectively) were performed with four isolated strains (Sphingopyxis sp. IM-1, IM-2 and IM-3; Paucibacter toxinivorans IM-4) and two bacterial degraders from the culture collection (Sphingosinicella microcystinivorans Y2; Paucibacter toxinivorans 2C20). Differences in microcystin degradation efficiencies between genotypes were found under different total organic carbon and total nitrogen concentrations. While mlr+ strains significantly improved microcystin degradation rates when exposed to other carbon and nitrogen sources, mlr− strains showed lower degradation efficiencies. This suggests that the presence of alternative carbon and nitrogen sources possibly competes with microcystins and impairs putative non-mlr microcystin degradation pathways. Considering the abundance of the mlr− bacterial population and the increasing frequency of eutrophic conditions in aquatic systems, further research on the diversity of this population and the characterization and conditions affecting non-mlr degradation pathways deserves special attention.

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Microcystin-LR biodegradation by Sphingopyxis sp. USTB-05

Cited by 26 publications

References 31 publications

Pathway for Biodegrading Microcystin-YR by Sphingopyxis sp. USTB-05

Pathway for Biodegrading Microcystin-YR by Sphingopyxis sp. USTB-05

A Mini Review on Microcystins and Bacterial Degradation

Presence or Absence of mlr Genes and Nutrient Concentrations Co-Determine the Microcystin Biodegradation Efficiency of a Natural Bacterial Community

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