title: Effects of Cylindrospermopsin Producing Cyanobacterium and Its Crude Extracts on a Benthic Green Alga-Competition or Allelopathy?
abstract: Cylindrospermopsin (CYN) is a toxic secondary metabolite produced by filamentous cyanobacteria which could work as an allelopathic substance, although its ecological role in cyanobacterial-algal assemblages is mostly unclear. The competition between the CYN-producing cyanobacterium Chrysosporum (Aphanizomenon) ovalisporum, and the benthic green alga Chlorococcum sp. was investigated in mixed cultures, and the effects of CYN-containing cyanobacterial crude extract on Chlorococcum sp. were tested by treatments with crude extracts containing total cell debris, and with cell debris free crude extracts, modelling the collapse of a cyanobacterial water bloom. The growth inhibition of Chlorococcum sp. increased with the increasing ratio of the cyanobacterium in mixed cultures (inhibition ranged from 26% to 87% compared to control). Interestingly, inhibition of the cyanobacterium growth also occurred in mixed cultures, and it was more pronounced than it was expected. The inhibitory effects of cyanobacterial crude extracts on Chlorococcum cultures were concentration-dependent. The presence of C. ovalisporum in mixed cultures did not cause significant differences in nutrient content compared to Chlorococcum control culture, so the growth inhibition of the green alga could be linked to the presence of CYN and/or other bioactive compounds.
authors.affiliation: Environmental Laboratory, Department of Environment and Conservation, Hajdú-Bihar County Government Office, 16 Hatvan street, Debrecen H-4025, Hungary. beres.viktoria@gmail.com.|Department of Hydrobiology, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary. beres.viktoria@gmail.com.
authors.forename: Viktória
authors.initials: V
authors.lastname: B-Béres
authors.affiliation: Department of Botany, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary. vasas.gabor@science.unideb.hu.
authors.forename: Gábor
authors.initials: G
authors.lastname: Vasas
authors.affiliation: Department of Hydrobiology, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary. dalmadobronoki@gmail.com.
authors.forename: Dalma
authors.initials: D
authors.lastname: Dobronoki
authors.affiliation: Department of Botany, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary. gondasandor@gmail.com.
authors.forename: Sándor
authors.initials: S
authors.lastname: Gonda
authors.affiliation: Department of Hydrobiology, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary. nagy.sandor.alex@science.unideb.hu.
authors.forename: Sándor Alex
authors.initials: SA
authors.lastname: Nagy
authors.affiliation: Department of Hydrobiology, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary. istvan.bacsi@gmail.com.
authors.forename: István
authors.initials: I
authors.lastname: Bácsi
mesh_terms: D000470:Alkaloids; D064089:Allelopathy / Q000502:physiology*; D046890:Aphanizomenon / Q000378:metabolism*; D001427:Bacterial Toxins / Q000302:isolation & purification / Q000378:metabolism / Q000633:toxicity; D000460:Chlorophyta / Q000378:metabolism*; D045424:Complex Mixtures / Q000378:metabolism; D000087522:Cyanobacteria Toxins; D064210:Secondary Metabolism; D014498:Uracil / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000378:metabolism / Q000633:toxicity
chemical_list: D000470:Alkaloids; D001427:Bacterial Toxins; D045424:Complex Mixtures; D000087522:Cyanobacteria Toxins; C089595:cylindrospermopsin; D014498:Uracil
keywords: allelopathy; co-culturing; cyanobacterium; eukaryotic alga; interaction; toxicity