Phenotypic variation in exopolysaccharide production in the marine, aerobic nitrogen-fixing unicellular cyanobacterium Cyanothece sp.

Reddy, K. J.; Soper, Brian W.; Tang, Jin‐Bao; Bradley, Richard L.

doi:10.1007/bf00340206

Cited by 56 publications

(37 citation statements)

References 28 publications

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“…Light microscopy. Cells were observed with a Reichert-Jung Polyvar photomicroscope (Vienna, Austria) using Nomarski differential interference contrast before and after they were negatively stained with India ink or after being stained with Alcian blue (in 3% acetic acid [pH 2.5]) (27).…”

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confidence: 99%

Sheathless Mutant of Cyanobacterium Gloeothece sp. Strain PCC 6909 with Increased Capacity To Remove Copper Ions from Aqueous Solutions

Micheletti

Pereira

Mannelli

et al. 2008

Appl Environ Microbiol

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The cyanobacterium Gloeothece sp. strain PCC 6909 and its sheathless mutant were tested for their abilities to remove copper ions from aqueous solutions, with the aim of defining the role of the various outermost polysaccharidic investments in the removal of the metal ions. Microscopy studies and chemical analyses revealed that, although the mutant does not possess a sheath, it releases large amounts of polysaccharidic material (released exocellular polysaccharides [RPS]) into the culture medium. The RPS of the wild type and the mutant are composed of the same 11 sugars, although they are present in different amounts, and the RPS of the mutant possesses a larger amount of acidic sugars and a smaller amount of deoxysugars than the wild type. Unexpectedly, whole cultures of the mutant were more effective in the removal of the heavy metal than the wild type (46.3 ؎ 3.1 and 26.7 ؎ 1.5 mg of Cu 2؉ removed per g of dry weight, respectively). Moreover, we demonstrated that the contribution of the sheath to the metal-removal capacity of the wild type is scarce and that the RPS of the mutant is more efficient in removing copper. This suggests that the metal ions are preferably bound to the cell wall and to RPS functional groups rather than to the sheath. Therefore, the increased copper binding efficiency observed with the sheathless mutant can be attributed to the release of a polysaccharide containing larger amounts and/or more accessible functional groups (e.g., carboxyl and amide groups).Cyanobacteria are a large and widespread group of photoautotrophic microorganisms that combine the ability to perform an oxygenic plant-like photosynthesis with typical prokaryotic features (40). Outside their atypical gram-negative cell walls (15), many strains possess outermost structures, mainly of a polysaccharidic nature, that differ in thickness and consistency. These structures can be referred to as sheaths, capsules, and slimes (4). The term sheath is applied to the usually thin and electron-dense layer surrounding the cells or the cell groups; the capsule refers to the thick and gelatinous layer intimately associated with the cell surface and presenting sharp outlines, whereas the term slime is used to designate the mucilaginous material that is dispersed around the organism but does not reflect the shape of the cells. During cell growth, aliquots of these polysaccharides can be released into the surrounding medium (referred to as released exocellular polysaccharides [RPS]), causing a progressive increase in its viscosity (4). The cyanobacterial exopolysaccharides (EPSs; a general term which includes both the polysaccharidic structures that remain intimately associated with the cell, i.e., the sheath and capsule, and those released into the culture medium, i.e., the RPS) exhibit some typical characteristics that distinguish them from the polymers synthesized by other bacteria: they frequently contain two different uronic acids, they build a polymer particularly rich in negatively charged groups, they possess a larger number o...

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confidence: 99%

Sheathless Mutant of Cyanobacterium Gloeothece sp. Strain PCC 6909 with Increased Capacity To Remove Copper Ions from Aqueous Solutions

Micheletti

Pereira

Mannelli

et al. 2008

Appl Environ Microbiol

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“…These color changes correspond to the growth of microbes attached to the bare reed and the gradual formation of a micro-scale colony along with formation of the biofilm; microbial cells buried in the extracellular polymeric substances (EPS), produced by the microorganisms attached to the reed, were well stained with alcian blue. Acidic polymers are usually stained well with this dye (24,25). The small colonies would eventually merge during continued microbial growth and EPS production, which along with the formation of the biofilm from microcolonies patchily distributed on the reed led to coverage of the surface.…”

Section: Biofilm Stainingmentioning

confidence: 99%

Analysis of How a Biofilm Forms on the Surface of the Aquatic Macrophyte Phragmites australis

et al. 2009

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The process by which a biofilm forms on the surface of the aquatic macrophyte Phragmites australis was investigated over a period of about two months (from mid-May to late-July, 2008) in Lake Biwa. The biofilm formed relatively quickly, its wet weight per unit area after seven day being that of a mature biofilm. This speed can be attributed to the many active bacteria in the early stage of its formation and the extracellular polymeric substances (EPS) they produce. The EPS carried electric charges that attracted nutrient ions from surrounding lake water, which, by electrostatic interaction, reached a high concentration as early as day 7 of the formation process. This significantly affected the biofilm community, which differed greatly from that of the lake water even at the beginning of biofilm formation. Brown amorphous compounds (a complex of organic and inorganic substances), covered the biofilm in the second half of its formation process producing a different community structure from that initially. This study revealed a fast and dynamic process of biofilm formation on the reed surface of reed.

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“…The presence of these slimy layers is essential for the protection and survival of the biofilm, but it presents a threat for the preservation of the lithic surfaces of monuments, which are subjected to mechanical stress (Reddy et al 1996) and chemical interactions (Crispim and Gaylarde 2005) causing changes in their structure and visible darkening.…”

Section: Introductionmentioning

confidence: 99%

Characteristics and role of the exocellular polysaccharides produced by five cyanobacteria isolated from phototrophic biofilms growing on stone monuments

et al. 2012

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Phenotypic variation in exopolysaccharide production in the marine, aerobic nitrogen-fixing unicellular cyanobacterium Cyanothece sp.

Cited by 56 publications

References 28 publications

Sheathless Mutant of Cyanobacterium Gloeothece sp. Strain PCC 6909 with Increased Capacity To Remove Copper Ions from Aqueous Solutions

Sheathless Mutant of Cyanobacterium Gloeothece sp. Strain PCC 6909 with Increased Capacity To Remove Copper Ions from Aqueous Solutions

Analysis of How a Biofilm Forms on the Surface of the Aquatic Macrophyte Phragmites australis

Characteristics and role of the exocellular polysaccharides produced by five cyanobacteria isolated from phototrophic biofilms growing on stone monuments

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