Secondary Metabolites of Antarctic Fungi Antagonistic to Aquatic Pathogenic Bacteria

Huibin Zhao; Chuner Cai; Xiaoyu Liu; Binghua Jiao; Bo Chen; Menghao Cai; Peimin He

doi:10.1515/biol-2018-0002

Secondary Metabolites of Antarctic Fungi Antagonistic to Aquatic Pathogenic Bacteria

Open Life Sci. 2018 Mar 20:13:11-21. doi: 10.1515/biol-2018-0002. eCollection 2018 Jan.

Authors

Huibin Zhao^{1

2}, Chuner Cai^{3

1

2

4}, Xiaoyu Liu^{3

5

4}, Binghua Jiao^{3

5

4}, Bo Chen⁶, Menghao Cai⁷, Peimin He^{1

2}

Affiliations

¹ College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai, 201306, China.
² National Demonstration Center for Experimental Fisheries Science Education, (Shanghai Ocean University), Shanghai, 201306, China.
³ Department of Biochemistry and Molecular Biology, College of Preclinical Medicine, Second Military Medical University, Shanghai, 200433, PR China.
⁴ Marine Biomedicine Institute, Second Military Medical University, Shanghai, 200433, China.
⁵ No.800 Xiangyin Road, Shanghai, 200433, PR China.
⁶ Polar Research Institute of China, Shanghai, 200136, China.
⁷ School of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.

Abstract

Polar microbial derived antibiotics have potential as alternatives to traditional antibiotics in treating fish against pathogenic bacteria. In this paper, 23 strains of polar fungi were fermented to detect bacteriostatic products on three aquatic pathogenic bacteria, subsequently the active fungus was identified. It was indicated that secondary metabolites of 23 strains weredistinct; of these, the extract of strain B-7 (belonging to Bjerkandera according to molecular identification) demonstrated a strong antibacterial activity to Streptococcus agalactiae, Vibrio anguillarum and Aeromonas hydrophila ATCC7966 by Kirby-Bauerpaper strip method. During one fermentation cycle, the pH curve of the fermentation liquor became lowest (4.0) on the 4^th day and rose back to 7.6 finally after 5 days, The residual sugar curve was decreased before stablising on the 6^th day. It is presumed that a large amount of alkaline secondary metabolites might have been produced during fermentation. This study focuses on antagonism between aquatic pathogenic bacteria and fermentation metabolites from Antarctic fungi for the first time, which may provide data on research of antibiotics against aquatic pathogenic bacteria.

Keywords: Aeromonashydrophila; Streptococcus agalactiae; Vibrio anguillarum; fungus; secondary metabolites.