L-valine, an antialgal amino acid from Streptomyces jiujiangensis JXJ 0074.sup.T

• Published in: Applied microbiology and biotechnology 2016-05, Vol.100 (10), p.4627
• Main Authors: Zhang, Bing-Huo, Chen, Wei, Li, Han-Quan, Yang, Jian-Yuan, Zha, Dai-Ming, Duan, Yan-Qing, N.Hozzein, Wael, Xiao, Min, Gao, Rui, Li, Wen-Jun
• Format: Article
• Language: English
• Subjects: Amino acids; Health aspects; Streptomyces
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-015-7150-8

An antialgal compound was isolated from the cultured broth of Streptomyces jiujiangensis JXJ 0074.sup.T by using bioassay methods. Based on the data of .sup.1H-NMR, .sup.13C-NMR, ESI-MS, and thin layer chromatography, the active compound was identified as L-valine, which showed antialgal activity mainly against Microcystis. L-valine exhibited greater antialgal activities than both L-lysine and copper sulfate (CuSO.sub.4) did on Microcystis aeruginosa lawn. However, M. aeruginosa recovered growth earlier with higher growth rate in L-valine treatment than in L-lysine treatment. L-valine dissipated completely within 2 days, much quicker than L-lysine (6 days), which resulted in the lysing of more than 80 % M. aeruginosa cells and the release of amount of intracellular microcystin-LR (MC-LR) within 2 days. As a resultant, the extracellular MC-LR content was more than twice of the control from day 1 to 5. Exposure to L-valine significantly promoted the synthesis of MC-LR. L-lysine also promoted the release and synthesis of MC-LR with much lesser efficiency than L-valine. L-valine could damage Microcystis severely, causing perforation and collapse of M. aeruginosa cells and decrease of the chlorophyll. The superoxide dismutase (SOD) activity in L-valine-treated cells of M. aeruginosa initially increased with 32.94 ± 3.37 % higher than the control after 36 h and then decreased quickly. However, the increase rate of superoxide anion radical (O.sub.2.sup.-) was much higher than that of SOD, which resulted in serious lipid peroxidation and accumulation of malondialdehyde (MDA). To our knowledge, this is the first report showing L-valine active against cyanobacteria.