Effects of lead(II) on the extracellular polysaccharide (EPS) production and colony formation of cultured Microcystis aeruginosa

2013 ◽  
Vol 67 (4) ◽  
pp. 803-809 ◽  
Author(s):  
Xiang-dong Bi ◽  
Shu-lin Zhang ◽  
Wei Dai ◽  
Ke-zhing Xing ◽  
Fan Yang
Keyword(s):  
Heavy Metals ◽  
Microcystis Aeruginosa ◽  
Colony Formation ◽  
Extracellular Polysaccharide ◽  
Extracellular Polysaccharides ◽  
Control Group ◽  
Natural Conditions ◽  
Laboratory Conditions ◽  
Large Colony ◽  
Middle Colonies

To investigate the effects of lead(II) on the production of extracellular polysaccharides (EPS), including bound extracellular polysaccharides (bEPS) and soluble extracellular polysaccharides (sEPS), and the colony formation of Microcystis aeruginosa, cultures of M. aeruginosa were exposed to four concentrations (5.0, 10.0, 20.0 and 40.0 mg/L) of lead(II) for 10 d under controlled laboratory conditions. The results showed that 5.0 and 10.0 mg/L lead(II) stimulated M. aeruginosa growth throughout the experiment while 20.0 and 40.0 mg/L lead(II) inhibited M. aeruginosa growth in the first 2 d exposure and then stimulated it. As compared to the control group, significant increases in the bEPS and sEPS production were observed in 20.0 and 40.0 mg/L lead(II) treatments (P < 0.05). Large colony formations were not observed throughout the experiment. However, four tested concentrations of lead(II) could significantly promote the formation of small and middle colonies after 10 d exposure (P < 0.05), and 40.0 mg/L lead(II) had the best stimulatory effect. Lead(II) could stimulate bEPS production, which conversely promoted colony formation, suggesting that heavy metals might be contributing to the bloom-forming of M. aeruginosa in natural conditions.

Impacts of different extracellular polysaccharides on colony formation and buoyancy of Microcystis aeruginosa

2020 ◽  
Vol 56 ◽  
pp. 28
Author(s):  
Kai Wei ◽  
Yoshimasa Amano ◽  
Motoi Machida
Keyword(s):  
Microcystis Aeruginosa ◽  
Colony Size ◽  
Colony Formation ◽  
Culture Medium ◽  
Divalent Metal ◽  
Extracellular Polysaccharides ◽  
Size Analysis ◽  
Light Conditions ◽  
Divalent Metal Cations ◽  
Calcium And Magnesium

On the surface of Microcystis cells, there is a carbohydrate called extracellular polysaccharides (EPS) playing a significant role in the colony formation of Microcystis. EPS consists of tightly cell-bound EPS (TB-EPS), and both of these substances are considered to be strongly related to the colony formation and buoyancy of Microcystis. In this study, Microcystis aeruginosa (strain: NIES-843) was used to examine the effects of EPS, TB-EPS, and divalent metal cations such as calcium and magnesium on the buoyancy and colony formation of M. aeruginosa NIES-843. Under various light conditions, the addition of TB-EPS into the culture medium induced M. aeruginosa NIES-843 to obtain high buoyancy at concentrations of Ca2+ and Mg2+ concentrations of 10 mg/L and 30 mg/L, respectively. Under the absence of light, the addition of EPS could lead M. aeruginosa to form a colony and obtain buoyancy, and the addition of TB-EPS could not significantly change the buoyancy of M. aeruginosa NIES-843. The colony size analysis showed that at the same cationic concentration, the addition of TB-EPS could induce M. aeruginosa to form the largest colony and present strong buoyancy. This study suggested that temperature and illumination are conducive to colony formation and present higher buoyancy of M. aeruginosa.

Effects of Intermittent Fluid Motion on Colony Formation of Microcystis aeruginosa in late Spring Raw Water

2013 ◽  
Vol 726-731 ◽  
pp. 3930-3933
Author(s):  
Lin Li ◽  
Yan Qin
Keyword(s):  
Water Flow ◽  
Microcystis Aeruginosa ◽  
Flow Rate ◽  
Colony Formation ◽  
Fluid Motion ◽  
Cell Number ◽  
Control Group ◽  
Raw Water ◽  
Ring Groove ◽  
Treatment Groups

The experiment was conducted by a small perspex ring groove, which generated intermittent water flow, under axenic condition and constant temperature and light, to understand the effects of water flow on colony formation ofMicrocystis aeruginosain the early spring raw water. The results showed that colony formation ofMicrocystis aeruginosawere observed in the control group and treatment groups. Colony characteristics in the treatment groups were more significant than in the control group, and the cell number of maximum colony in the treatment groups were 2.6-4 times more than in control group. So, water flow promoted to the colony formation ofMicrocystis aeruginosa, and colony ofMicrocystis aeruginosamost easily formed at flow rate of 25cm·s-1. The phenomenon may be the interaction of the polysaccharide produced by algae in light and cell-cell higher contact rate in water flow. There are optimal flow rate of colony formation for too high water flow producing mechanical shear force to reduce colony formation. The represent study provided the scientific basis for revealing colony formation of algae.

scholarly journals Kemampuan hambat ekstrak temulawak (Curcuma xanthorrhiza Roxb.) terhadap adhesi bakteri Streptococcus mutans

2017 ◽  
Vol 7 (1) ◽  
pp. 53
Author(s):  
Erin Imaniar B ◽  
Sri Kunarti ◽  
Widya Saraswati
Keyword(s):  
Streptococcus Mutans ◽  
Extracellular Polysaccharide ◽  
Tooth Surface ◽  
Plate Count ◽  
Extracellular Polysaccharides ◽  
Control Group ◽  
Control Group Design ◽  
Post Test ◽  
Planktonic Form ◽  
Curcuma Xanthorrhiza

Background : Streptococcus mutans is the most cariogenic microorganism in the oral cavity. Streptococcus mutans has the ability to use dietary carbohydrates, such as sucrose, to synthesize extracellular polysaccharides (glucan and fructan) through glucosyltransferase and fructosyltransferase. Extracellular polysaccharide has a role in promoting the adhesion of bacteria. Chlorhexidine  is the gold standard as antiplaque agent but chlorhexidine is not fully able to inhibit the adhesion of bacteria because it has an effect that can increase gtfC and gtfD expression on S. mutans in planktonic form. Temulawak extract (Curcuma xanthorrhiza Roxb.) contains of curcumin, xanthorrhizol, saponin, flavonoid and tannin that have an effect to inhibit activity and secretion of glucosyltransferase and fructosyltransferase. Purpose: The aim of this study is to find out the ability of temulawak extract (Curcuma xanthorrhiza Roxb.) to inhibit adhesion of Streptococcus mutans.  Method: This study was designed as an experimental laboratory study with post test only control group design using Streptococcus mutans. Temulawak was extracted using maceration method. The number of bacteria that can perform adhesion to the tooth surface can be determined by performing calculations using formulas plate count method. Result: Temulawak extract (Curcuma xanthorrhiza Roxb.) at concentrations of 25%, 37.5%, 50% and chlorhexidine can inhibit bacterial adhesion of Streptococcus mutans. Conclusion: Temulawak extract at concentration of 50% and 37.5% has the best ability to inhibit the adhesion of bacteria among other treatment groups.

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