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Under light stress of 1000 /imol s-1m-2 (λ=400 - 700 nm) for 140 min cyanobacteria mats of "tintenstrich" formations on limestone rocks of Kobylaňska-Valley, west of Cracow, Poland showed reduction of the potential and eiTective quantum yield variables ∆F/Fm' and Fv/Fm3, respectively of PSII and the samples first recovered partly after six days. Also, the Fo level, known to be affected by environmental stress, increased rapidly due to strong light intensity. Sulphite stress (100 mM) was first manifested very clearly after a long, 15h exposure, but not during the first 40 min. Thus, these terrestrial cyanobacteria appear to be less sensitive to sulphite stress than eucaryotic algae, lichens and higher plants studied so far. It is not yet clear if this is due to i) special adaptation of these free living terrestrial cyanobacteria growing in a heavily polluted area, ii) buffering capacity of the limestone support, or iii) other factors.
Eukaryotes acquired the ability to process photosynthesis by engulfing a cyanobacterium and transforming it into a genuine organelle called the plastid. This event, named primary endosymbiosis, occurred once more than a billion years ago, and allowed the emergence of the Archaeplastida, a monophyletic supergroup comprising the green algae and plants, the red algae and the glaucophytes. Of the other known cases of symbiosis between cyanobacteria and eukaryotes, none has achieved a comparable level of cell integration nor reached the same evolutionary and ecological success than primary endosymbiosis did. Reasons for this unique accomplishment are still unknown and difficult to comprehend. The exploration of plant genomes has revealed a considerable amount of genes closely related to homologs of Chlamydiae bacteria, and probably acquired by horizontal gene transfer. Several studies have proposed that these transferred genes, which are mostly involved in the functioning of the plastid, may have helped the settlement of primary endosymbiosis. Some of these studies propose that Chlamydiae and cyanobacterial symbionts coexisted in the eukaryotic host of the primary endosymbiosis, and that Chlamydiae provided solutions for the metabolic symbiosis between the cyanobacterium and the host, ensuring the success of primary endosymbiosis. In this review, I present a reevaluation of the contribution of Chlamydiae genes to the genome of Archaeplastida and discuss the strengths and weaknesses of this tripartite model for primary endosymbiosis.
This study focused on site-specific preferences of potentially harmful cyanobacterium Gloeotrichia echinulata to occur in lakes with different ecological and trophic conditions. Its pelagic growth was studied in six lakes from June to September in 1986-1988, 2000-2001 and 2009. In total, 78 samples were taken from the epilimnion (stratified lakes) or the whole water column (non-stratified lakes). Analyses of phytoplankton and environmental variables were performed according to standard methods. During summer, a distinct maximum of the Gloeotrichia growth was observed in July or August (the warmest period). Bloom events of G. echinulata occurred in lakes where the light and oxygen conditions were significantly inferior while the phosphorus content remained on a slightly elevated level. The distinct domination of this cyanobacterium (above 40% of the total phytoplankton biomass) was limited to lakes with a high, moderate or even poor ecological status, and to the meso-eutrophic or eutrophic state of lakes. However, G. echinulata occurred in a broader range of ecological and trophic conditions of lakes. The historical approach to mass occurrence of G. echinulata, with its possible contribution to phosphorus translocation from sediment to the pelagic zone, suggested its importance as an indicator of progressive ecological and trophic deterioration of lakes. This indication should be very useful for establishment of main targets in water management.
The paper suggests to worldwide problem of standing waters eutrophication. It describes one of the possible solutions of the problem - design and application of the electrolytic equipment. It indicates effects of its application in practice. The second part of the paper deals with possibilities of economic efficiency evaluation of development and application of the equipment.
The atricle is devoted to the study of the cultivation of cyanobacteria Microcystis aeruginosa (Kützing) Kützing, Microcystis pulverea (H.C.Wood) Forti. in the presence of basalt tuff. The possibility of using basalt tuff as an adsorbing material for regulating the number of cyanobacteria and preventing toxic “water bloom” in fluid circuits. The study analyzes the change in the biomass amount and the dynamics of the proportion of dead cyanobacteria in response to the presence of basalt tuff in the culture medium. It is noted that the use of basalt tuff leads to a decrease in the growth activity of cultures of Microcystis aeruginosa, Microcystis pulverea, manifested in an increase in the number of dead cells and slowdown the accumulation of cyanobacterial biomass. These effects are the result of a decrease in the amount of available nitrogen in the nutrient medium.
The common and ecologically important cyanobacterial form-genus Leptolyngbya is widely distributed in numerous ecosystems over the Earth's biosphere. Several morphospecies dominate microbial communities in polar habitats, but their diversity and local ecological significance are little known. Several articles characterising strains isolated from Antarctic coastal habitats by molecular methods were published, but knowledge of their phenotype and ecological characters are indispensable for future detailed environmental studies. Distinct morpho- and ecotypes (ecologically important morphospecies) from maritime Antarctica are characterised in this article. Eight dominant Leptolyngbya types from subaerophytic and freshwater habitats were recognised, and four of them (L. borchgrevinkii, L. fritschiana, L. nigrescens and L. vincentii) are described as new distinct species.
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