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Effects of Cylindrospermopsin Producing Cyanobacterium and Its Crude Extracts on a Benthic Green Alga-Competition or Allelopathy?

B-Béres V, Vasas G, Dobronoki D, Gonda S, Nagy SA, Bácsi I - Mar Drugs (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Environmental Laboratory, Department of Environment and Conservation, Hajdú-Bihar County Government Office, 16 Hatvan street, Debrecen H-4025, Hungary. beres.viktoria@gmail.com.

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.

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Changes of cell numbers in control (containing Chlorococcum sp. or C. ovalisporum cells only) and in mixed (containing Chlorococcum sp. and C. ovalisporum cells, as well) cultures. Initial Chlorococcum sp. cell numbers were 0.2 × 106 mL−1 in control and mixed cultures in all cases (a–c). Initial C. ovalisporum cell numbers were in control and mixed cultures: (a) 0.2 × 106 mL−1 (1:1 ratio); (b) 0.4 × 106 mL−1 (1:2 ratio); and (c) 0.8 × 106 mL−1 (1:4 ratio). Significant differences among the growth of Chlorococcum sp. cultures are indicated with aC–cC; significant differences among the growth of C. ovalisporum cultures are indicated with aA–cA.
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marinedrugs-13-06703-f001: Changes of cell numbers in control (containing Chlorococcum sp. or C. ovalisporum cells only) and in mixed (containing Chlorococcum sp. and C. ovalisporum cells, as well) cultures. Initial Chlorococcum sp. cell numbers were 0.2 × 106 mL−1 in control and mixed cultures in all cases (a–c). Initial C. ovalisporum cell numbers were in control and mixed cultures: (a) 0.2 × 106 mL−1 (1:1 ratio); (b) 0.4 × 106 mL−1 (1:2 ratio); and (c) 0.8 × 106 mL−1 (1:4 ratio). Significant differences among the growth of Chlorococcum sp. cultures are indicated with aC–cC; significant differences among the growth of C. ovalisporum cultures are indicated with aA–cA.

Mentions: There were significant differences between the growth of the green alga in control and in mixed cultures (p < 0.05; Figure 1a). Furthermore, growth of Chlorococcum differed significantly from each other in mixed cultures 1:1 and 1:4, as well as 1:2 and 1:4 (p < 0.05). The growth of the green alga was continuous but with a lower extent compared to the control culture on the second week in mixed cultures with 1:1 and 1:2 ratio. The cell number of Chlorococcum was 25% and 44% lower, respectively, than the cell number in control culture on the last (14th) day (Figure 1a,b). The decrease of the green algal cell number was the most conspicuous in the mixed culture with 1:4 ratio, growth of Chlorococcum sp. was inhibited during the whole experiment (Figure 1c). The cell number of the benthic green alga was significantly lower (p < 0.05) in this mixed culture than both in control culture and in the other mixed cultures (Figure 1c).


Effects of Cylindrospermopsin Producing Cyanobacterium and Its Crude Extracts on a Benthic Green Alga-Competition or Allelopathy?

B-Béres V, Vasas G, Dobronoki D, Gonda S, Nagy SA, Bácsi I - Mar Drugs (2015)

Changes of cell numbers in control (containing Chlorococcum sp. or C. ovalisporum cells only) and in mixed (containing Chlorococcum sp. and C. ovalisporum cells, as well) cultures. Initial Chlorococcum sp. cell numbers were 0.2 × 106 mL−1 in control and mixed cultures in all cases (a–c). Initial C. ovalisporum cell numbers were in control and mixed cultures: (a) 0.2 × 106 mL−1 (1:1 ratio); (b) 0.4 × 106 mL−1 (1:2 ratio); and (c) 0.8 × 106 mL−1 (1:4 ratio). Significant differences among the growth of Chlorococcum sp. cultures are indicated with aC–cC; significant differences among the growth of C. ovalisporum cultures are indicated with aA–cA.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663549&req=5

marinedrugs-13-06703-f001: Changes of cell numbers in control (containing Chlorococcum sp. or C. ovalisporum cells only) and in mixed (containing Chlorococcum sp. and C. ovalisporum cells, as well) cultures. Initial Chlorococcum sp. cell numbers were 0.2 × 106 mL−1 in control and mixed cultures in all cases (a–c). Initial C. ovalisporum cell numbers were in control and mixed cultures: (a) 0.2 × 106 mL−1 (1:1 ratio); (b) 0.4 × 106 mL−1 (1:2 ratio); and (c) 0.8 × 106 mL−1 (1:4 ratio). Significant differences among the growth of Chlorococcum sp. cultures are indicated with aC–cC; significant differences among the growth of C. ovalisporum cultures are indicated with aA–cA.
Mentions: There were significant differences between the growth of the green alga in control and in mixed cultures (p < 0.05; Figure 1a). Furthermore, growth of Chlorococcum differed significantly from each other in mixed cultures 1:1 and 1:4, as well as 1:2 and 1:4 (p < 0.05). The growth of the green alga was continuous but with a lower extent compared to the control culture on the second week in mixed cultures with 1:1 and 1:2 ratio. The cell number of Chlorococcum was 25% and 44% lower, respectively, than the cell number in control culture on the last (14th) day (Figure 1a,b). The decrease of the green algal cell number was the most conspicuous in the mixed culture with 1:4 ratio, growth of Chlorococcum sp. was inhibited during the whole experiment (Figure 1c). The cell number of the benthic green alga was significantly lower (p < 0.05) in this mixed culture than both in control culture and in the other mixed cultures (Figure 1c).

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Environmental Laboratory, Department of Environment and Conservation, Hajdú-Bihar County Government Office, 16 Hatvan street, Debrecen H-4025, Hungary. beres.viktoria@gmail.com.

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.

Show MeSH
Related in: MedlinePlus