title: A marine algicidal Thalassospira and its active substance against the harmful algal bloom species Karenia mikimotoi.
abstract: The aim of the present study was to obtain a marine bacterium active against Karenia mikimotoi from the East China Sea and to characterize its extracellular algicidal substances. Using preparative high-performance liquid chromatography (prep-HPLC) and electrospray ionization/quadrupole-time of flight mass spectrometer coupled with a high-performance liquid chromatography (LC/MS-Q-TOF) system, we purified the alga-lysing substance produced by strain ZR-2 and determined its molecular structure. Based on morphology and l6S ribosomal DNA (rDNA) sequence analysis, the ZR-2 strain was highly homologous to Thalassospira species. Algicidal activity against K. mikimotoi was detected in the cell-free filtrate but not in bacterial cells. The alga-lysing substance produced by ZR-2 was ethanol-soluble and thermostable, with a retention time of 6.3 min and a measured elemental composition of C7H5O2 ([M-H](-) ion at m/z 121.0295). The alga-lysing substance produced by ZR-2 was determined to be benzoic acid. Compared with the negative control, both purified ZR-2 bacteria-free filtrate and standard benzoic acid promoted K. mikimotoi cell disruption and induced K. mikimotoi cell content leakage. Our study is the first to report benzoic acid activity against K. mikimotoi as well as production of benzoic acid by a Thalassospira species.
authors: Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China.
authors: Xiuhua
authors: X
authors: Lu
authors: Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China.
authors: Bin
authors: B
authors: Zhou
authors: Shandong Provincial Key Laboratory of Applied Mycology, College of Life Science, Agricultural University of Qingdao, Qingdao, 266109, China.
authors: Lili
authors: L
authors: Xu
authors: Shandong Provincial Key Laboratory of Applied Mycology, College of Life Science, Agricultural University of Qingdao, Qingdao, 266109, China.
authors: Lin
authors: L
authors: Liu
authors: Shandong Provincial Key Laboratory of Applied Mycology, College of Life Science, Agricultural University of Qingdao, Qingdao, 266109, China.
authors: Gangyuan
authors: G
authors: Wang
authors: Coastal Landscape Management Office, Qingdao, 266100, China.
authors: Xiaodong
authors: X
authors: Liu
authors: Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China. luxiuhua6@sina.com.
authors: Xuexi
authors: X
authors: Tang
mesh_terms: D000898:Antibiosis; D019817:Benzoic Acid / Q000378:metabolism; D002681:China; D002853:Chromatography, Liquid; D004269:DNA, Bacterial / Q000302:isolation & purification; D004141:Dinoflagellida / Q000254:growth & development* / Q000382:microbiology*; D057097:Harmful Algal Bloom; D013058:Mass Spectrometry; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000302:isolation & purification; D012244:Rhodospirillaceae / Q000302:isolation & purification / Q000502:physiology*; D017422:Sequence Analysis, DNA; D014871:Water Microbiology; D014876:Water Pollution
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D019817:Benzoic Acid
keywords: Algicide; Benzoic acid; Harmful algal blooms; Karenia mikimotoi; Thalassospira