A bacterial strain EMS with the capability of degrading microcystins (MCs) was isolated from Lake Taihu, China. The bacterium was tentatively identified as a Stenotrophomonas sp. The bacterium could completely consume MC-LR and MC-RR within 24 hours at a concentration of 0.7 μg/mL and 1.7 μg/mL, respectively. The degradation of MC-LR and MC-RR by EMS occurred preferentially in an alkaline environment. In addition, mlrA gene involved in the degradation of MC-LR and MC-RR was detected in EMS. Due to the limited literature this gene has rare homologues. Sequencing analysis of the translated protein from mlrA suggested that MlrA might be a transmembrane protein, which suggests a possible new protease family having unique function.
References
[1]
Wu, S; Wang, S; Yang, H; Xie, P; Ni, L; Xu, J. Field studies on the environmental factors in controlling microcystin production in the subtropical shallow lakes of the Yangtze River. Bull. Environ. Contam. Toxicol？2008, 80, 329–334.
[2]
Yang, H; Xie, P; Xu, J; Zheng, L; Deng, D; Zhou, Q; Wu, S. Seasonal variation of microcystin concentration in Lake Chaohu, a shallow subtropical lake in the People's Republic of China. Bull. Environ. Contam. Toxicol？2006, 77, 367–374.
[3]
Xiao, FG; Zhao, XL; Tang, J; Gu, XH; Zhang, JP; Niu, WM. Determination of microcystin-LR in water from Lake Tai, China. Bull. Environ. Contam. Toxicol？2009, 82, 230–233.
[4]
Welker, M; von D？hren, H. Cyanobacterial peptides-Nautre’s own combinatorial biosynthesis. FEMS Microbiol. Rev？2006, 30, 530–563.
Dawsan, RM. The toxicology of microcystins. Toxicon？1998, 36, 953–962.
[7]
Briand, JF; Jacquet, S; Bernard, C; Humbert, JF. Health hazards for terrestrial vertebrates from toxic cyanobacteria in surface water ecosystems. Vet. Res？2003, 34, 361–377.
[8]
？egura, B; Lah, TT; Filipi？, M. The role of reactive oxyen species in microcystin-LR-induced DNA damage. Toxicology？2004, 200, 59–68.
[9]
？egura, B; Sedmak, B; Filipi？, M. Microcystin-LR induces oxidative DNA damage in human hepatoma cell line HepG2. Toxicon？2003, 41, 41–48.
[10]
Li, H; Xie, P; Li, G; Hao, L; Xiong, Q. In vivo study on the effects of microcystin extracts on the expression profiles of proto-oncogenes (c-fos, c-jun and c-myc) in liver, kidney and testis of male Wistar rats injected i.v. with toxins. Toxicon？2009, 53, 169–175.
[11]
Mezhoud, K; Praseuth, D; Puiseux-Dao, S; Fran？ois, J; Bernard, C; Edery, M. Global quantitative analysis of protein expression and phosphorylation status in the liver of the medaka fish (Oryzias latipes) exposed to microcystin-LR I. Balneation study. Aquat. Toxicol？2007, 86, 166–175.
[12]
Crush, JR; Briggs, LR; Sprosen, JM; Nichols, SN. Effect of irrigation with lake water containing microcystins on microcystin content and growth of ryegrass, clover, rape, and lettuce. Environ. Toxicol？2008, 23, 246–252.
[13]
J？rvenp？？, S; Lundberg-Niinist？, C; Spoof, L; Sj？vall, O; Tyystj？rvi, E; Meriluoto, J. Effects of microcystins on broccoli and mustard, and analysis of accumulated toxin by liquid chromatography-mass spectrometry. Toxicon？2007, 49, 865–874.
[14]
Máthé, C; M-Hamvas, M; Vasas, G; Surányi, G; Bácsi, I; Beyer, D; Tóth, S; Tímár, M; Borbély, G. Microcystin-LR, a cyanobacterial toxin, induces growth inhibition and histological alterations in common reed (Phragmites australis) plants regenerated from embryogenic calli. New Phytol？2007, 176, 824–835.
[15]
Pflugmacher, S; Aulhorn, M; Grimm, B. Influence of a cyanobacterial crude extract containing microcystin-LR on the physiology and antioxidative defence systems of different spinach variants. New Phytol？2007, 175, 482–489.
[16]
Park, HD; Sasaki, Y; Maruyama, T; Yanagisawa, E; Hiraishi, A; Kato, K. Degradation of the cyanobacterial hepatotoxin microcystin by a new bacterium isolated from a hypertrophic lake. Environ. Toxicol？2001, 16, 337–343.
[17]
Mao, XW; Xu, F; Xu, B; Gao, Y. Changes of water quality and eutrophication in Taihu Lake. Water Resour. Prot？2009, 25, 48–51.
[18]
Dong, X; Bennion, H; Battarbee, R; Yang, X; Yang, H; Liu, E. Tracking eutrophication in Taihu Lake using the diatom record: potential and problems. J. Paleolimnol？2008, 40, 413–429.
[19]
Liu, W; Qiu, R. Water eutrophication in China and the combating strategies. J. Chem. Technol. Biotechnol？2007, 82, 781–786.
[20]
Duan, H; Ma, R; Xu, X; Kong, F; Zhang, S; Kong, W; Hao, J; Shang, L. Two-decade reconstruction of algal blooms in China's Lake Taihu. Environ. Sci. Technol？2009, 43, 3522–3528.
[21]
Guidelines for Drinking-Water Quality, 3rd ed ed.; WHO (World Health Organization): Geneva, Switzerland, 2004; Volume 1.
[22]
Standards for drinking water quality (GB 5749-2006); MHPRC, (Ministry of Health of the People’s Republic of China): Beijing, China, 2006.
[23]
Edwards, C; Lawton, LA. Bioremediation of cyanotoxins. In Advances in Applied Microbiology; Laskin, AI, Gadd, GM, Sariaslani, S, Eds.; Academic Press: New York, NY, USA, 2009; Volume 67, pp. 109–129.
[24]
Bourne, DG; Blakeley, RL; Riddles, P; Jones, GJ. Biodegradation of the cyanobacterial toxin microcystin LR in natural water and biologically active slow sand filters. Water Res？2006, 40, 1294–1302.
[25]
Ho, L; Meyn, T; Keegan, A; Hoefel, D; Brooks, J; Saint, CP; Newcombe, G. Bacterial degradation of microcystin toxins within a biologically active sand filter. Water Res？2006, 40, 768–774.
[26]
Hu, LB; Yang, JD; Zhou, W; Yin, YF; Chen, J; Shi, ZQ. Isolation of a Methylobacillus sp. that degrades of microcyctin toxins associated with cyanobacteria. N. Biotechnol？2009, 26, 205–211.
[27]
Bourne, DG; Jones, GJ; Blakeley, RL; Jones, A; Negri, AP; Riddles, P. Enzymatic pathway for the bacterial degradation of the cyanobacterial cyclic peptide toxin microcystin LR. Appl. Environ. Microbiol？1996, 62, 4086–4094.
[28]
Satio, T; Okano, K; Park, HD; Itayama, T; Inamori, Y; Neilan, BA; Burns, BP; Sugiura, N. Detection and sequencing of the microcystin LR degrading gene, mlrA, from new bacteria isolated from Japanese lakes. FEMS Microbiol. Lett？2003, 229, 271–276.
[29]
Harada, KI; Imanishi, S; Kato, H; Mizuno, M; Ito, E; Tsuji, K. Isolation of Adda from microcystin-LR by microbial degradation. Toxicon？2004, 44, 107–109.
[30]
Edwards, C; Graham, D; Fowler, N; Lawton, LA. Biodegradation of microcystins and nodularin in freshwaters. Chemosphere？2008, 73, 1315–1321.
[31]
Ho, L; Gaudieux, AL; Fanok, S; Newcombe, G; Humpage, AR. Bacterial degradation of microcystin toxins in drinking water eliminates their toxicity. Toxicon？2007, 50, 438–441.
[32]
Lemes, GA; Kersanach, R; Pinto, LS; Dellagostin, OA; Yunes, JS; Matthiensen, A. Biodegradation of microcystins by aquatic Burkholderia sp. from a South Brazilian coastal lagoon. Ecotoxicol. Environ. Saf？2008, 69, 358–365.
[33]
Manage, PM; Edwards, C; Singh, BK; Lawton, LA. Isolation and identification of novel microcystin-degrading bacteria. Appl. Environ. Microbiol？2009, 75, 6924–6928.
[34]
Bourne, DG; Riddles, P; Jones, GJ; Smith, W; Blakeley, RL. Characterisation of a gene cluster involved in bacterial degradation of the cyanobacterial toxin microcystin LR. Environ. Toxicol？2001, 16, 523–534.
[35]
Huan, HL; Han, L; Li, JH; Wang, YP. Isolation and identification of five microcystin degrading bacterial strains. J. Lake Sci？2006, 18, 184–188.
[36]
Liu, HY; Huan, HL; Wang, YW; Li, JH; Zhou, YM. Molecular identification of a microcystin-degrading bacteria strain S3 and its biodegradation of microcystin. Acta Sci. Circumst？2007, 27, 1145–1150.
Ghosh, D; Roy, K; Srinivasan, V; Mueller, T; Tuovinen, OH; Sublette, K; Peacock, A; Radosevich, M. In-situ enrichment and analysis of atrazine-degradation microbial communities using atrazine-containing porous beads. Soil Biol. Biochem？2009, 41, 1331–1334.
[39]
Satio, T; Sugiura, N; Itayama, T; Inamori, Y; Matsumura, M. Degradation characteristics of microcystins by isolated bacteria from Lake Kasumigaura. J. Water Suppl. Res. Technol. AQUA？2003, 52, 13–18.
[40]
Jones, GJ; Bourne, DG; Blakeley, RL; Doelle, H. Degradation of the cyanobacterial hepatotoxin microcystin by aquatic bacteria. Nat. Toxins？1994, 2, 228–235.
[41]
Sedmak, B; Carmeli, S; Eler？ek, T. “Non-toxic” cyclic peptides induce lysis of cyanobacteria – an effective cell population density control mechanism in cyanobacterial blooms. Microb. Ecol？2008, 56, 201–209.
[42]
Takenaka, S; Watanable, MF. Microcystin LR degradation by Pseudomonas aeruginosa alkaline protease. Chemosphere？1997, 34, 749–757.
[43]
Tsuji, K; Asakawa, M; Yojiro, A; Sumino, T; Harada, KI. Degradation of microcystins using immobilized microorganism isolated in a neutrophic lake. Chemosphere？2006, 65, 117–124.
[44]
Valeria, AM; Ricardo, EJ; Stephan, P; Alberto, WD. Degradation of microcystin-RR by Sphingomonas sp. CBA4 isolated from San Roque reservoir (Córdoba–Argentina). Biodegradation？2006, 17, 447–455.
[45]
Christiansen, G; Fastner, J; Erhard, M; B？rner, T; Dittmann, E. Microcystin biosynthesis in Planktothrix: genes, evolution, and manipulation. J. Bacteriol？2003, 185, 564–572.
[46]
Ure？a, JM; Merlos-Suárez, A; Baselga, J; Arribas, J. The cytoplasmic carboxy-terminal amino acid determines the subcellular localization of proTGF-(alpha) and membrane type matrix metalloprotease (MT1-MMP). J. Cell Sci？1999, 112, 773–784.
[47]
Sun, X; Liu, X; Guo, S; Huang, B; Li, W; Wang, X; Lin, J; Tang, K. Cloning and analysis of a novel conserved membrane zinc metalloprotease family from Solanum surattense. Russ. J. Plant Physiol？2007, 54, 63–73.
[48]
Lane, DJ; Pace, B; Olsen, GJ; Sogin, ML; Pace, NR. Rapid determination of 16S ribosomal RNA sequences for phylogenetic analyses. Proc. Natl. Acad. Sci. USA？1985, 882, 6955–6959.
[49]
Larkin, MA; Blackshields, G; Brown, NP; Chenna, R; McGettigan, PA; McWilliam, H; Valentin, F; Wallace, IM; Wilm, A; Lopez, R; Thompson, JD; Gibson, TJ; Higgins, DG. Clustal W and Clustal X version 2.0. Bioinformatics？2007, 23, 2947–2948.
[50]
Kumar, S; Dudley, J; Nei, M; Tamura, K. MEGA: A biologist-centric software for evolutionary analysis of DNA and protein sequences. Brief. Bioinform？2008, 9, 299–306.
