title: Isolation of a Poterioochromonas capable of feeding on Microcystis aeruginosa and degrading microcystin-LR.
abstract: Algal blooms have become a worldwide issue recently, especially those comprised of toxic cyanobacteria. Grazers' predation of bloom-forming algae plays an important role in water clearing. In this study, a species of golden alga (strain ZX1), capable of feeding on the toxic cyanobacteria Microcystis aeruginosa, was isolated and identified as Poterioochromonas sp. (GenBank accession: EU586184) on the basis of morphological characteristics and 18s rRNA gene sequencing. Feeding experiments showed that ZX1 could clear high densities of M. aeruginosa (7.3 x 10(5)-4.3 x 10(6) cells mL(-1)) in a short time (40 h), with inhibition ratios higher than 99.9%. ZX1 grew during the feeding processes and achieved a maximum density of 10-20% of the initial M. aeruginosa density. Furthermore, this study is the first to report that ZX1 was able to degrade microcystin-LR (MC-LR) in cells of M. aeruginosa while digesting the whole cells, and that the degradation process was determined to be carried out inside the ZX1 cell. For a total MC-LR (intra- and extracellular) concentration of up to 114 microg L(-1), 82.7% was removed in 40 h. This study sheds light on the importance of golden alga in aquatic microbial ecosystems and in the natural transportation/transformation of MC-LR.
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, Department of Environmental Science and Engineering, Tsinghua University, Beijing, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Zhang
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Hu
authors.forename: Yu
authors.initials: Y
authors.lastname: Hong
authors.forename: Jia
authors.initials: J
authors.lastname: Yang
mesh_terms: D001673:Biodegradation, Environmental; D044523:Chrysophyta / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology*; D017753:Ecosystem; D005068:Eutrophication; D005247:Feeding Behavior; D008387:Marine Toxins; D052998:Microcystins / Q000378:metabolism*; D046931:Microcystis / Q000254:growth & development*; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA; D014871:Water Microbiology
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D012337:RNA, Ribosomal, 18S; C057862:cyanoginosin LR