title: Effects of Dracontomelon duperreanum defoliation extract on Microcystis aeruginosa: physiological and morphological aspects.
abstract: Harmful cyanobacteria bloom contributes to economic loss as well as the threat to human health. Agricultural waste products, particularly straw, have been used to control bloom while arbor plant is the potential candidate for limiting antialgal activity. This study investigated the use of Dracontomelon duperreanum defoliation extract (DDDE) to inhibit the activity of Microcystis aeruginosa. The primary goal of the research was to explore the solution to control cyanobacterial bloom. The photosynthetic activity, cell morphology, membrane integrity, and esterase activity of M. aeruginosa were determined using phytoplankton analyzer pulse amplitude modulation (Phyto-PAM) and flow cytometry before and after exposure to DDDE. The inhibitory rate of M. aeruginosa was about 99.6 % on day 15 when exposed to 2.0 g L(-1). A reduction of chlorophyll a (Chl-a) activity and changes in cell membrane suggested the algistatic property of DDDE. Inhibition of photosynthetic activity was reflected by changing mean Chl-a fluorescence intensity (MFI) which was about 52.5 % on day 15 when exposed to 2.0 g L(-1) DDDE as well as relative electron transport rates (rETRs) of algal cell. These changes might contribute to the suppression of M. aeruginosa. Algal cell exposed to DDDE may lead to cell volume reduction or slow growth. This resulted in a decreased proportion of normal or swollen granular cells after DDDE treatment.
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou, 510006, China.|School of Civil and Environmental Engineering, Shenzhen Polytechnic, Shenzhen, 518055, China.
authors.forename: Xiaoxiong
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Civil and Environmental Engineering, Shenzhen Polytechnic, Shenzhen, 518055, China.
authors.forename: Chenchun
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Applied Science Discipline, Hong Kong Institute of Vocational Education, Hong Kong, China SAR.
authors.forename: Yim-Tong
authors.initials: YT
authors.lastname: Szeto
authors.affiliation: Applied Science Discipline, Hong Kong Institute of Vocational Education, Hong Kong, China SAR.
authors.forename: Ho-Kin
authors.initials: HK
authors.lastname: Li
authors.affiliation: Applied Science Discipline, Hong Kong Institute of Vocational Education, Hong Kong, China SAR.
authors.forename: Kwei-Lam
authors.initials: KL
authors.lastname: Yam
authors.affiliation: College of Environment and Energy, South China University of Technology, Guangzhou, 510006, China. cexjwang@scut.edu.cn.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Wang
mesh_terms: D027926:Anacardiaceae / Q000737:chemistry*; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D000458:Cyanobacteria / Q000378:metabolism; D004579:Electron Transport; D005453:Fluorescence; D057097:Harmful Algal Bloom / Q000187:drug effects; D046931:Microcystis / Q000187:drug effects*; D010788:Photosynthesis / Q000187:drug effects; D010839:Phytoplankton / Q000378:metabolism; D010936:Plant Extracts / Q000633:toxicity*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D002734:Chlorophyll; D000077194:Chlorophyll A
keywords: Dracontomelon duperreanum; Esterase activity; Flow cytometry; Microcystis aeruginosa; Phyto-PAM