scholarly journals Isolation of axenic cyanobacterium and the promoting effect of associated bacterium on axenic cyanobacterium

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Suqin Gao ◽  
Yun Kong ◽  
Jing Yu ◽  
Lihong Miao ◽  
Lipeng Ji ◽  
...  

Abstract Background Harmful cyanobacterial blooms have attracted wide attention all over the world as they cause water quality deterioration and ecosystem health issues. Microcystis aeruginosa associated with a large number of bacteria is one of the most common and widespread bloom-forming cyanobacteria that secret toxins. These associated bacteria are considered to benefit from organic substrates released by the cyanobacterium. In order to avoid the influence of associated heterotrophic bacteria on the target cyanobacteria for physiological and molecular studies, it is urgent to obtain an axenic M. aeruginosa culture and further investigate the specific interaction between the heterotroph and the cyanobacterium. Results A traditional and reliable method based on solid-liquid alternate cultivation was carried out to purify the xenic cyanobacterium M. aeruginosa FACHB-905. On the basis of 16S rDNA gene sequences, two associated bacteria named strain B905–1 and strain B905–2, were identified as Pannonibacter sp. and Chryseobacterium sp. with a 99 and 97% similarity value, respectively. The axenic M. aeruginosa FACHB-905A (Microcystis 905A) was not able to form colonies on BG11 agar medium without the addition of strain B905–1, while it grew well in BG11 liquid medium. Although the presence of B905–1 was not indispensable for the growth of Microcystis 905A, B905–1 had a positive effect on promoting the growth of Microcystis 905A. Conclusions The associated bacteria were eliminated by solid-liquid alternate cultivation method and the axenic Microcystis 905A was successfully purified. The associated bacterium B905–1 has the potentiality to promote the growth of Microcystis 905A. Moreover, the purification technique for cyanobacteria described in this study is potentially applicable to a wider range of unicellular cyanobacteria.

2020 ◽  
Author(s):  
Suqin Gao ◽  
Yun Kong ◽  
Jing Yu ◽  
Lihong Miao ◽  
Lipeng Ji ◽  
...  

Abstract Background: Harmful cyanobacterial blooms have attracted wide attention all over the world as they cause water quality deterioration and ecosystem health issues. Microcystis aeruginosa associated with a large number of bacteria is one of the most common and widespread bloom-forming cyanobacteria that secret toxins. These associated bacteria are considered to benefit from organic substrates released by the cyanobacterium. In order to avoid the influence of associated heterotrophic bacteria on the target cyanobacteria for physiological and molecular studies, it is urgent to obtain an axenic M. aeruginosa culture and further investigate the specific interaction between the heterotroph and the cyanobacterium.Results: A traditional and reliable method based on solid-liquid alternate cultivation is carried out to purify the xenic cyanobacterium M. aeruginosa FACHB-905. On the basis of 16S rDNA gene sequences, two associated bacteria named strain B905-1 and strain B905-2, are identified as Pannonibacter sp. and Chryseobacterium sp. with a 99% and 97% similarity value, respectively. The axenic M. aeruginosa FACHB-905A (Microcystis 905A) is not able to form colonies on BG11 agar medium without the addition of strain B905-1, while it grows well in BG11 liquid medium. Although the presence of B905-1 is not indispensable for the growth of Microcystis 905A, B905-1 has a positive effect on promoting the growth of Microcystis 905A. Conclusions: The associated bacteria are eliminated by solid-liquid alternate cultivation method and the axenic Microcystis 905A is successfully purified. The associated bacterium B905-1 has the potential to promote the growth of Microcystis 905A. Moreover, the purification technique for cyanobacteria described in this study is potentially applicable to a wider range of unicellular cyanobacteria.


2020 ◽  
Author(s):  
Suqin Gao ◽  
Yun Kong ◽  
Jing Yu ◽  
Lihong Miao ◽  
Lipeng Ji ◽  
...  

Abstract Background: Harmful cyanobacterial blooms have attracted wide attention all over the world as they cause water quality deterioration and ecosystem health issues. Microcystis aeruginosa associated with a large number of bacteria is one of the most common and widespread bloom-forming cyanobacteria that secret toxins. These associated bacteria are considered to benefit from organic substrates released by the cyanobacterium. In order to avoid the influence of associated heterotrophic bacteria on the target cyanobacteria for physiological and molecular studies, it is urgent to obtain an axenic M. aeruginosa culture and further investigate the specific interaction between the heterotroph and the cyanobacterium. Results: A traditional and reliable method based on solid-liquid alternate cultivation is carried out to purify the xenic cyanobacterium M. aeruginosa FACHB-905. On the basis of 16S rDNA gene sequences, two associated bacteria named strain B905-1 and strain B905-2, are identified as Pannonibacter sp. and Chryseobacterium sp. with a 99% and 97% similarity value, respectively. The axenic M. aeruginosa FACHB-905A (Microcystis 905A) is not able to form colonies on BG11 agar medium without the addition of strain B905-1, while it grows well in BG11 liquid medium. Although the presence of B905-1 is not indispensable for the growth of Microcystis 905A, B905-1 has a positive effect on promoting the growth of Microcystis 905A. Conclusions: The associated bacteria are eliminated by solid-liquid alternate cultivation method and the axenic Microcystis 905A is successfully purified. The associated bacterium B905-1 has the potential to promote the growth of Microcystis 905A. Moreover, the purification technique for cyanobacteria described in this study is potentially applicable to a wider range of unicellular cyanobacteria.


2020 ◽  
Author(s):  
Suqin Gao ◽  
Yun Kong ◽  
Jing Yu ◽  
Lihong Miao ◽  
Lipeng Ji ◽  
...  

Abstract Background: Harmful algal blooms have attracted wide attention all over the world as they cause water quality deterioration and ecosystem health issues. Microcystis aeruginosa associated with a large number of bacteria is one of the most common and widespread bloom-forming cyanobacteria that secret toxins. These associated bacteria are considered to benefit from organic substrates released by the cyanobacterium. In order to avoid the influence of associated bacteria on the target cyanobacteria for physiological and molecular studies, it is urgent to obtain an axenic M. aeruginosa culture and further investigate the specific interaction between the cyanobacterium-associated bacterium and the cyanobacterium.Results: A traditional and reliable method based on solid-liquid alternate cultivation is carried out to purify the xenic cyanobacterium M. aeruginosa FACHB-905. On the basis of 16S rDNA gene sequences, two associated bacteria named strain B905-1 and strain B905-2, are identified as Pannonibacter sp. and Chryseobacterium sp. with a 99% and 97% similarity value, respectively. The axenic M. aeruginosa FACHB-905A is not able to form colonies on BG11 agar medium without the addition of strain B905-1, while it grows well in BG11 liquid medium. Although the presence of B905-1 is not indispensable for the growth of M. aeruginosa FACHB-905A, B905-1 has a positive effect on promoting the growth of M. aeruginosa FACHB-905A. Conclusions: The associated bacteria are eliminated by solid-liquid alternate cultivation method and the axenic M. aeruginosa FACHB-905A is successfully purified. The associated bacterium B905-1 has the potential to promote the growth of M. aeruginosa FACHB-905A. Moreover, the purification technique for cyanobacteria described in this study is potentially applicable to a wider range of unicellular cyanobacteria.


2020 ◽  
Author(s):  
Yun Kong ◽  
Suqin Gao ◽  
Jing Yu ◽  
Lihong Miao ◽  
Lipeng Ji ◽  
...  

Abstract In order to avoid the influence of associated bacteria on the target cyanobacteria for physiological and molecular studies, a traditional and reliable method based on solid-liquid alternate cultivation is carried out to purify the non-axenic cyanobacterium Microcystis aeruginosa FACHB-905. On the basis of 16S rDNA gene sequences, two associated bacteria named strain B905-1 and strain B905-2, are identified as Pannonibacter sp. and Chryseobacterium sp. with a 99% and 97% similarity value, respectively. To better investigate the general interaction between the bacterium and the cyanobacterium, the effect of strain B905-1 on the axenic cyanobacterium M. aeruginosa FACHB-905A is studied. Results indicate that the axenic M. aeruginosa FACHB-905A could not form colonies on BG11 agar medium without the addition of strain B905-1, while it grows well in BG11 liquid medium. Although the presence of B905-1 was not indispensable for the growth of M. aeruginosa FACHB-905A, B905-1 had a positive effect on promoting the growth of M. aeruginosa FACHB-905A. The purification technique for cyanobacteria described in this study is potentially applicable to a wider range of filamentous cyanobacteria.


2020 ◽  
Vol 74 (3) ◽  
pp. 122-128
Author(s):  
Christine M. Egli ◽  
Regiane S. Natumi ◽  
Martin R. Jones ◽  
Elisabeth M.-L. Janssen

Harmful cyanobacterial blooms in freshwater ecosystems produce bioactive secondary metabolites including cyanopeptides that pose ecological and human health risks. Only adverse effects of one class of cyanopeptides, microcystins, have been studied extensively and have consequently been included in water quality assessments. Inhibition is a commonly observed effect for enzymes exposed to cyanopeptides and has mostly been investigated for human biologically relevant model enzymes. Here, we investigated the inhibition of ubiquitous aquatic enzymes by cyanobacterial metabolites. Hydrolytic enzymes are utilized in the metabolism of aquatic organisms and extracellularly by heterotrophic bacteria to obtain assimilable substrates. The ubiquitous occurrence of hydrolytic enzymes leads to the co-occurrence with cyanopeptides especially during cyanobacterial blooms. Bacterial leucine aminopeptidase and alkaline phosphatase were exposed to cyanopeptide extracts of different cyanobacterial strains ( Microcystis aeruginosa wild type and microcystin-free mutant, Planktothrix rubescens) and purified cyanopeptides. We observed inhibition of aminopeptidase and phosphatase upon exposure, especially to the apolar fractions of the cyanobacterial extracts. Exposure to the dominant cyanopeptides in these extracts confirmed that purified microcystins, aerucyclamide A and cyanopeptolin A inhibit the aminopeptidase in the low mg L–1 range while the phosphatase was less affected. Inhibition of aquatic enzymes can reduce the turnover of nutrients and carbon substrates and may also impair metabolic functions of grazing organisms.


Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2147
Author(s):  
Anjali Krishnan ◽  
Xiaozhen Mou

Harmful cyanobacterial blooms pose an environmental health hazard due to the release of water-soluble cyanotoxins. One of the most prevalent cyanotoxins in nature is microcystins (MCs), a class of cyclic heptapeptide hepatotoxins, and they are produced by several common cyanobacteria in aquatic environments. Once released from cyanobacterial cells, MCs are subjected to physical chemical and biological transformations in natural environments. MCs can also be taken up and accumulated in aquatic organisms and their grazers/predators and induce toxic effects in several organisms, including humans. This brief review aimed to summarize our current understanding on the chemical structure, exposure pathway, cytotoxicity, biosynthesis, and environmental transformation of microcystins.


Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 699
Author(s):  
Małgorzata Kucała ◽  
Michał Saładyga ◽  
Ariel Kaminski

Cyanotoxins are harmful to aquatic and water-related organisms. In this study, Lemna trisulca was tested as a phytoremediation agent for three common cyanotoxins produced by bloom-forming cyanobacteria. Cocultivation of L. trisulca with Dolichospermum flos-aquae in BG11 medium caused a release of the intracellular pool of anatoxin-a into the medium and the adsorption of 92% of the toxin by the plant—after 14 days, the total amount of toxin decreased 3.17 times. Cocultivation with Raphidopsis raciborskii caused a 2.77-time reduction in the concentration of cylindrospermopsin (CYN) in comparison to the control (62% of the total pool of CYN was associated with the plant). The greatest toxin limitation was noted for cocultivation with Microcystis aeruginosa. After two weeks, the microcystin-LR (MC-LR) concentration decreased more than 310 times. The macrophyte also influenced the growth and development of cyanobacteria cells. Overall, 14 days of cocultivation reduced the biomass of D. flos-aquae, M. aeruginosa, and R. raciborskii by 8, 12, and 3 times, and chlorophyll a concentration in comparison to the control decreased by 17.5, 4.3, and 32.6 times, respectively. Additionally, the macrophyte stabilized the electrical conductivity (EC) and pH values of the water and affected the even uptake of cations and anions from the medium. The obtained results indicate the biotechnological potential of L. trisulca for limiting the development of harmful cyanobacterial blooms and their toxicity.


2021 ◽  
Vol 9 (7) ◽  
pp. 1495
Author(s):  
Tim Piel ◽  
Giovanni Sandrini ◽  
Gerard Muyzer ◽  
Corina P. D. Brussaard ◽  
Pieter C. Slot ◽  
...  

Applying low concentrations of hydrogen peroxide (H2O2) to lakes is an emerging method to mitigate harmful cyanobacterial blooms. While cyanobacteria are very sensitive to H2O2, little is known about the impacts of these H2O2 treatments on other members of the microbial community. In this study, we investigated changes in microbial community composition during two lake treatments with low H2O2 concentrations (target: 2.5 mg L−1) and in two series of controlled lake incubations. The results show that the H2O2 treatments effectively suppressed the dominant cyanobacteria Aphanizomenon klebahnii, Dolichospermum sp. and, to a lesser extent, Planktothrix agardhii. Microbial community analysis revealed that several Proteobacteria (e.g., Alteromonadales, Pseudomonadales, Rhodobacterales) profited from the treatments, whereas some bacterial taxa declined (e.g., Verrucomicrobia). In particular, the taxa known to be resistant to oxidative stress (e.g., Rheinheimera) strongly increased in relative abundance during the first 24 h after H2O2 addition, but subsequently declined again. Alpha and beta diversity showed a temporary decline but recovered within a few days, demonstrating resilience of the microbial community. The predicted functionality of the microbial community revealed a temporary increase of anti-ROS defenses and glycoside hydrolases but otherwise remained stable throughout the treatments. We conclude that the use of low concentrations of H2O2 to suppress cyanobacterial blooms provides a short-term pulse disturbance but is not detrimental to lake microbial communities and their ecosystem functioning.


2018 ◽  
Vol 5 (1) ◽  
pp. 6-16
Author(s):  
Laurent André ◽  
Christomir Christov ◽  
Arnault Lassin ◽  
Mohamed Azaroual

AbstractThe knowledge of the thermodynamic behavior of multicomponent aqueous electrolyte systems is of main interest in geo-, and environmental-sciences. The main objective of this study is the development of a high accuracy thermodynamic model for solution behavior, and highly soluble M(III)Cl3(s) (M= Al, Fe, Cr) minerals solubility in Na-Al(III)-Cr(III)-Fe(III)-Cl-H2O system at 25°C. Comprehensive thermodynamic models that accurately predict aluminium, chromium and iron aqueous chemistry and M(III) mineral solubilities as a function of pH, solution composition and concentration are critical for understanding many important geochemical and environmental processes involving these metals (e.g., mineral dissolution/alteration, rock formation, changes in rock permeability and fluid flow, soil formation, mass transport, toxic M(III) remediation). Such a model would also have many industrial applications (e.g., aluminium, chromium and iron production, and their corrosion, solve scaling problems in geothermal energy and oil production). Comparisons of solubility and activity calculations with the experimental data in binary and ternary systems indicate that model predictions are within the uncertainty of the data. Limitations of the model due to data insufficiencies are discussed. The solubility modeling approach, implemented to the Pitzer specific interaction equations is employed. The resulting parameterization was developed for the geochemical Pitzer formalism based PHREEQC database.


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