Search results for "CYANOBACTERIA"
showing 10 items of 130 documents
Microalgae in the postgenomic era: a blooming reservoir for new natural products
2013
Bacteria, fungi, algae and higher plants are the most prolific producers of natural products (secondary metabolites). Compared to macroalgae, considerably fewer natural products have been isolated from microalgae, which offer the possibility of obtaining sufficient and well-defined biological material from laboratory cultures. Interest in microalgae is reinforced by large-scale data sets from genome sequencing projects and the development of genetic tools such as transformation protocols. This review highlights what is currently known about the biosynthesis and biological role of natural products in microalgae, with examples from isoprenoids, complex polyketides, nonribosomal peptides, poly…
Intertidal epilithic bacteria diversity changes along a naturally occurring carbon dioxide and pH gradient.
2014
Intertidal epilithic bacteria communities are important components of coastal ecosystems, yet few studies have assessed their diversity and how it may be affected by changing environmental parameters. Submarine CO2 seeps produce localised areas of CO2-enriched seawater with reduced pH levels. We utilised the seawater pH/CO2 gradient at Levante Bay (Italy) to test the hypothesis that epilithic bacteria communities are modified by exposure to seawater with the varying chemical parameters. Biofilms were sampled from three sites exposed to seawater with different pH/CO2 levels and diversity determined using high-throughput sequencing of 16S rRNA genes. Seawater pCO2 concentrations were increase…
Elimination of cyanobacteria and microcystins in irrigation water—effects of hydrogen peroxide treatment
2020
AbstractCyanobacterial blooms pose a risk to wild and domestic animals as well as humans due to the toxins they may produce. Humans may be subjected to cyanobacterial toxins through many routes, e.g., by consuming contaminated drinking water, fish, and crop plants or through recreational activities. In earlier studies, cyanobacterial cells have been shown to accumulate on leafy plants after spray irrigation with cyanobacteria-containing water, and microcystin (MC) has been detected in the plant root system after irrigation with MC-containing water. This paper reports a series of experiments where lysis of cyanobacteria in abstracted lake water was induced by the use of hydrogen peroxide and…
Interacting effects of simulated eutrophication, temperature increase, and microplastic exposure on Daphnia
2020
The effects of multiple stressors are difficult to separate in field studies, and their interactions may be hard to predict if studied in isolation. We studied the effects of decreasing food quality (increase in cyanobacteria from 5 to 95% simulating eutrophication), temperature increase (by 3 °C), and microplastic exposure (1% of the diet) on survival, size, reproduction, and fatty acid composition of the model freshwater cladoceran Daphnia magna. We found that food quality was the major driver of Daphnia responses. When the amount of cyanobacteria increased from 5 to 95% of the diet, there was a drastic decrease in Daphnia survival (from 81 ± 15% to 24 ± 21%), juvenile size (from 1.8 ± 0.…
Carbon photoassimilation by sharply stratified phototrophic communities at the chemocline of Lake Arcas (Spain)
1998
Three populations of phototrophic microorganisms were found closely stratified in the chemocline of the holomictic Lake Arcas. Cryptomonas spp. reached a maximum population density in microaerobic waters above dense plates of Oscillatoria cf. ornata and Chromatium weissei, whose maxima were found in the deeper sulfide-rich waters. High photoassimilation rates were found during the stratification period at the chemocline (up to 197.63 mg C m−3 h−1), especially at depths at which maximal densities of prokaryotic phototrophs were located, whereas much lower values were observed in the mixed zone of the lake. Despite these high rates, the contribution of carbon photoassimilation at the chemocli…
The Proteome and Lipidome of Synechocystis sp. PCC 6803 Cells Grown under Light-Activated Heterotrophic Conditions*
2015
Cyanobacteria are photoautotrophic prokaryotes with a plant-like photosynthetic machinery. Because of their short generation times, the ease of their genetic manipulation, and the limited size of their genome and proteome, cyanobacteria are popular model organisms for photosynthetic research. Although the principal mechanisms of photosynthesis are well-known, much less is known about the biogenesis of the thylakoid membrane, hosting the components of the photosynthetic, and respiratory electron transport chain in cyanobacteria. Here we present a detailed proteome analysis of the important model and host organism Synechocystis sp. PCC 6803 under light-activated heterotrophic growth condition…
Biological Strategies of Lichen Symbionts to the Toxicity of Lead (Pb)
2019
Lichens are symbiotic organisms, originated by mutualistic associations of heterotrophic fungi (mycobiont), photosynthetic partners (photobionts) which can be either cyanobacteria (cyanobionts) or green microalgae (phycobionts), and bacterial consortia. They are poikilohydric organisms without cuticles or nutrient absorption organs adapted to anhydrobiosis. They present a large range of tolerance to abiotic stress (UV radiation, extreme temperatures, high salinity, mineral excess, etc.) and prosper all around the Earth, especially in harsh habitats, including Antarctica and warm deserts. Their biodiversity is widely used as a bioindicator of environmental quality due to this diversity of to…
Biochemical bases for a widespread tolerance of cyanobacteria to the phosphonate herbicide glyphosate
2008
Possible non-target effects of the widely used, non-selective herbicide glyphosate were examined in six cyanobacterial strains, and the basis of their resistance was investigated. All cyanobacteria showed a remarkable tolerance to the herbicide up to millimolar levels. Two of them were found to possess an insensitive form of glyphosate target, the shikimate pathway enzyme 5-enol-pyruvyl-shikimate-3-phosphate synthase. Four strains were able to use the phosphonate as the only phosphorus source. Low uptake rates were measured only under phosphorus deprivation. Experimental evidence for glyphosate metabolism was also obtained in strains apparently unable to use the phosphonate. Results suggest…
Cultivation of algae with indigenous species – Potentials for regional biofuel production
2011
The massive need for sustainable energy has led to an increased interest in new energy resources, such as production of algae, for use as biofuel. There are advantages to using algae, for example, ...
Phosphorus NMR as a tool to study mineralization of organophosphonates—The ability of Spirulina spp. to degrade glyphosate
2007
Abstract A commercially available mixed culture of Spirulina spp. exhibited a remarkable ability to degrade the widely used organophosphorus herbicide glyphosate, that served as sole source of either phosphorus or nitrogen for cyanobacterial growth. 31P NMR analysis of spent media appeared to be an effective and simple technique to follow disappearance of the phosphonate and release of inorganic phosphate in biodegradation process(es).