title: Isolation and characterization of an algicidal bacterium indigenous to lake Taihu with a red pigment able to lyse microcystis aeruginosa.
abstract: OBJECTIVE
  To isolate and characterize indigenous algicidal bacteria and their algae-lysing compounds active against Microcystis aeruginosa, strains TH1, TH2, and FACHB 905.
  
  
  METHODS
  The bacteria were identified using the Biolog automated microbial identification system and 16S rDNA sequence analysis. The algae-lysing compounds were isolated and purified by silica gel column chromatography and reverse-phase high performance liquid chromatography. Their structures were confirmed by Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared (FT-IR) spectroscopy. Algae-lysing activity was observed using microscopy.
  
  
  RESULTS
  The algae-lysing bacterium LTH-2 isolated from Lake Taihu was identified as Serratia marcescens. Strain LTH-2 secreted a red pigment identified as prodigiosin (C20H25N3O), which showed strong lytic activity with algal strains M. aeruginosa TH1, TH2, and FACHB 905 in a concentration-dependent manner. The 50% inhibitory concentration (IC50) of prodigiosin with the algal strains was 4.8 (± 0.4)× 10⁻² μg/mL, 8.9 (± 1.1)× 10⁻² μg/mL, and 1.7 (± 0.1)× 10⁻¹ μg/mL in 24 h, respectively.
  
  
  CONCLUSIONS
  The bacterium LTH-2 and its pigment had strong Microcystis-lysing activity probably related to damage of cell membranes. The bacterium LTH-2 and its red pigment are potentially useful for regulating blooms of harmful M. aeruginosa.
authors: Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing 210009, Jiangsu, China.
authors: Fei
authors: F
authors: Yang
authors: Hai Yan
authors: HY
authors: Wei
authors: Xiao Qin
authors: XQ
authors: Li
authors: Yun Hui
authors: YH
authors: Li
authors: Xiao Bo
authors: XB
authors: Li
authors: Li Hong
authors: LH
authors: Yin
authors: Yue Pu
authors: YP
authors: Pu
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D060106:Lakes; D046931:Microcystis / Q000254:growth & development*; D010802:Phylogeny
chemical_list: D000900:Anti-Bacterial Agents
keywords: Algae-lysing; Algicidal bacteria; Harmful algal blooms (HABs); Microcystis aeruginosa; Serratia marcescens