Objective Fungal keratitis（FK） is a vision-threatening infection,whose treatment requires more effective and safer anti-fungal agent exploitation urgently.With this aim,we focused on the effect of an extracellular p...Objective Fungal keratitis（FK） is a vision-threatening infection,whose treatment requires more effective and safer anti-fungal agent exploitation urgently.With this aim,we focused on the effect of an extracellular polysaccharide on fungal adhesion to human corneal epithelial cells.Methods We performed the cytotoxicity assays of the extracellular polysaccharide EPS-II from an antarctic bacterium Pseudoaltermonas and evaluated its inhibitory effect on Candida albicans cells＇ adherence to human corneal epithelial cells（HCECs）.Results EPS-II,which displayed minor cytotoxicity but also promoted proliferation of HCECs,could inhibit the adherence of yeast cells to HCECs in a dose-dependent manner.EPS-II could also suppress the subsequent PI3K/AKT signaling pathway,and thereby decrease the expression of early inflammatory cytokines.Conclusions ExtracellularpolysaccharideEPS-IIwassuggestedasanewnaturalagentforattenuatingFK.展开更多
Extracellular polymeric substances （EPS） are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewat...Extracellular polymeric substances （EPS） are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewatering of activated sludge. Furthermore, EPS also show great efficiency in binding heavy metals. So EPS are key factors influencing reduction in sludge volume and mass, as well as activity and utilization of sludge. EPS are of considerable environmental interest and hundreds of articles on EPS have been published abroad, while information on EPS in China is limited. In this paper, results of over 60 publications related to constituents and characteristics of EPS and their influences on flocculation, settling and dewatering of sludge are compiled and analyzed. Metal-binding ability of EPS is also discussed, together with a brief consideration of possible research interests in the future.展开更多
Twenty-seven antarctic bacteria producing extracellular polysaccharide （EPS） were selected from 57 strains by staining technology. The effects of major environmental factors on the growth and EPS production of Pseud...Twenty-seven antarctic bacteria producing extracellular polysaccharide （EPS） were selected from 57 strains by staining technology. The effects of major environmental factors on the growth and EPS production of Pseudoalteromonas sp. S - 15 - 13 were investigated, and the EPS was separated and purified for characterization analysis. The results showed that the optimal conditions for the EPS production were culture period, 56 h; growth temperature, 8 ℃ ; carbon source, 1.0% glucose; NaCI concentration, 3.0% ; pH 6.0 - 7.0. The EPS was purified by cold ethanol precipitation, proteins removal, ion exchange chromatography and gel chromatography technology. The molecular mass of EPS - H was 62 kDa as determined by the high performance gel permeation chromatography. Its sugar composition was a homopolymer of marmose analyzed by gas chromatograph spectroscopy. After repeated freezing and thawing of the bacteria hiomass in the presence of EPS, the bacterial growth was much higher than that observed after freezing in the absence of EPS and the difference augmented with the increase of freeze-thaw cycles. It is hypothesized that the adaptation of Pseudoalteromonas sp. S- 15 - 13 to the antarctic marine conditions, characterized by low temperature, high NaCl concentration and repeated freeze-thaw cycles, might be related to the EPS production ability.展开更多
Bacteria of the genus Flammeovirga can digest complex polysaccharides (CPs), but no details have been reported regarding the CP depolymerases of these bacteria. MY04, an agarolytic marine bacterium isolated from coast...Bacteria of the genus Flammeovirga can digest complex polysaccharides (CPs), but no details have been reported regarding the CP depolymerases of these bacteria. MY04, an agarolytic marine bacterium isolated from coastal sediments, has been identified as a new member of the genus Flammeovirga. The MY04 strain is able to utilize multiple CPs as a sole carbon source and grows well on agarose, mannan, or xylan. This strain produces high concentrations of extracellular proteins (490 mg L-1 ± 18.2 mg L-1 liquid culture) that exhibit efficient and extensive degradation activities on various polysaccharides, especially agarose. These proteins have an activity of 310 U mg-1 ± 9.6 U mg-1 proteins. The extracellular agarase system (EAS) in the crude extracellular enzymes contains at least four agarose depolymerases, which are with molecular masses of approximately 30-70 kDa. The EAS is stable at a wide range of pH values (6.0-11.0), temperatures (0-50℃), and sodium chloride (NaCl) concentrations (0- 0.9 mol L-1). Two major degradation products generated from agarose by the EAS are identified to be neoagarotetraose and neoagarohexaose, suggesting that β-agarases are the major constituents of the MY04 EAS. These results suggest that the Flammeovirga strain MY04 and its polysac-charide-degradation system hold great promise in industrial applications.展开更多
Oral diseases related to dental biofilms continue to afflict the majority of the world＇s population. Among them, dental caries continues to be the single most prevalent and costly oral infectious disease （Marsh, 200...Oral diseases related to dental biofilms continue to afflict the majority of the world＇s population. Among them, dental caries continues to be the single most prevalent and costly oral infectious disease （Marsh, 2003; Dye et al., 2007）. Dental caries results from the interaction of specific bacteria with constituents of the diet within a dental biofilm known as plaque （Bowen, 2002）. Sucrose is considered to be the ＂arch criminal＂ from the dietary aspect because it serves as a substrate for synthesis of extracellular （EPS） and intracellular （IPS） polysaccharides in dental biofilm and is also fermentable （Bowen, 2002）.展开更多
Extracellular polysaccharide from Tremella aurantialba (TEP) significantly inhibited H2O2-induced haemolysis of RBCs, significantly decreased the amount of malondialdehyde (MDA) produced in mice liver homogenates as a...Extracellular polysaccharide from Tremella aurantialba (TEP) significantly inhibited H2O2-induced haemolysis of RBCs, significantly decreased the amount of malondialdehyde (MDA) produced in mice liver homogenates as a result of autoxidation, and inhibited VitC-Fe2+-induced swelling of liver mitochondria.展开更多
The rough crystal of exopolysaccharide produced by Enterococcus durans, a strain of lactic acid bacteria screened from the intestine of a cock in our laboratory, was purified by CM-cellulose column chromatography, DEA...The rough crystal of exopolysaccharide produced by Enterococcus durans, a strain of lactic acid bacteria screened from the intestine of a cock in our laboratory, was purified by CM-cellulose column chromatography, DEAE-Sephadex A-25 ionexchange and Sephadex G-100 gel chromatography to give EPS-Ⅰ. The EPS-Ⅰ was eluted as a single peak in HPLC analysis, indicating the homogeneity of EPS-Ⅰ and free from low-molecular-weight polysaccharides. The molecular weight of the EPS-Ⅰ was determined as 42 000 by the light scattering method. The result of its elemental analysis was C 41.08% and H 7.23% without the elements of N, P and S. Monosaccharide analysis showed that it was composed of Glc and Man in a molar ratio of 4∶1. Sugar composition analysis, methylation analysis and 1H and 13C NMR spectroscopy revealed that the EPS-Ⅰ was composed of pentasaccharide repeating units. The sequence of sugar residues was determined by using two-dimensional NMR, including heteronuclear multiple-bond correlation(HMBC) and nuclear overhauser effect spectroscopy(NOESY). The structure of the pentasaccharide repeating unit of EPS-Ⅰ was given, a new excellular polysaccharide from lactic acid bacterium compared with other EPSs was reported.展开更多
基金partially supported by the National Natural Scientific Foundation (81000369)the Doctor Foundation of Shandong Province (BS2009SW018)
文摘Objective Fungal keratitis（FK） is a vision-threatening infection,whose treatment requires more effective and safer anti-fungal agent exploitation urgently.With this aim,we focused on the effect of an extracellular polysaccharide on fungal adhesion to human corneal epithelial cells.Methods We performed the cytotoxicity assays of the extracellular polysaccharide EPS-II from an antarctic bacterium Pseudoaltermonas and evaluated its inhibitory effect on Candida albicans cells＇ adherence to human corneal epithelial cells（HCECs）.Results EPS-II,which displayed minor cytotoxicity but also promoted proliferation of HCECs,could inhibit the adherence of yeast cells to HCECs in a dose-dependent manner.EPS-II could also suppress the subsequent PI3K/AKT signaling pathway,and thereby decrease the expression of early inflammatory cytokines.Conclusions ExtracellularpolysaccharideEPS-IIwassuggestedasanewnaturalagentforattenuatingFK.
基金The National Natural Science Foundation of China (No. 50578053) and the Harbin Young Scientist Fund (No. 2003AFXXJ025)
文摘Extracellular polymeric substances （EPS） are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewatering of activated sludge. Furthermore, EPS also show great efficiency in binding heavy metals. So EPS are key factors influencing reduction in sludge volume and mass, as well as activity and utilization of sludge. EPS are of considerable environmental interest and hundreds of articles on EPS have been published abroad, while information on EPS in China is limited. In this paper, results of over 60 publications related to constituents and characteristics of EPS and their influences on flocculation, settling and dewatering of sludge are compiled and analyzed. Metal-binding ability of EPS is also discussed, together with a brief consideration of possible research interests in the future.
文摘Twenty-seven antarctic bacteria producing extracellular polysaccharide （EPS） were selected from 57 strains by staining technology. The effects of major environmental factors on the growth and EPS production of Pseudoalteromonas sp. S - 15 - 13 were investigated, and the EPS was separated and purified for characterization analysis. The results showed that the optimal conditions for the EPS production were culture period, 56 h; growth temperature, 8 ℃ ; carbon source, 1.0% glucose; NaCI concentration, 3.0% ; pH 6.0 - 7.0. The EPS was purified by cold ethanol precipitation, proteins removal, ion exchange chromatography and gel chromatography technology. The molecular mass of EPS - H was 62 kDa as determined by the high performance gel permeation chromatography. Its sugar composition was a homopolymer of marmose analyzed by gas chromatograph spectroscopy. After repeated freezing and thawing of the bacteria hiomass in the presence of EPS, the bacterial growth was much higher than that observed after freezing in the absence of EPS and the difference augmented with the increase of freeze-thaw cycles. It is hypothesized that the adaptation of Pseudoalteromonas sp. S- 15 - 13 to the antarctic marine conditions, characterized by low temperature, high NaCl concentration and repeated freeze-thaw cycles, might be related to the EPS production ability.
基金supported by the Scientific Research Fund of the Sichuan Provincial Education Department(09ZA181)by grants from the State Key Laboratory of Microbial Technology (M2010-12)the National Science Foundation of China (30870001)
文摘Bacteria of the genus Flammeovirga can digest complex polysaccharides (CPs), but no details have been reported regarding the CP depolymerases of these bacteria. MY04, an agarolytic marine bacterium isolated from coastal sediments, has been identified as a new member of the genus Flammeovirga. The MY04 strain is able to utilize multiple CPs as a sole carbon source and grows well on agarose, mannan, or xylan. This strain produces high concentrations of extracellular proteins (490 mg L-1 ± 18.2 mg L-1 liquid culture) that exhibit efficient and extensive degradation activities on various polysaccharides, especially agarose. These proteins have an activity of 310 U mg-1 ± 9.6 U mg-1 proteins. The extracellular agarase system (EAS) in the crude extracellular enzymes contains at least four agarose depolymerases, which are with molecular masses of approximately 30-70 kDa. The EAS is stable at a wide range of pH values (6.0-11.0), temperatures (0-50℃), and sodium chloride (NaCl) concentrations (0- 0.9 mol L-1). Two major degradation products generated from agarose by the EAS are identified to be neoagarotetraose and neoagarohexaose, suggesting that β-agarases are the major constituents of the MY04 EAS. These results suggest that the Flammeovirga strain MY04 and its polysac-charide-degradation system hold great promise in industrial applications.
文摘Oral diseases related to dental biofilms continue to afflict the majority of the world＇s population. Among them, dental caries continues to be the single most prevalent and costly oral infectious disease （Marsh, 2003; Dye et al., 2007）. Dental caries results from the interaction of specific bacteria with constituents of the diet within a dental biofilm known as plaque （Bowen, 2002）. Sucrose is considered to be the ＂arch criminal＂ from the dietary aspect because it serves as a substrate for synthesis of extracellular （EPS） and intracellular （IPS） polysaccharides in dental biofilm and is also fermentable （Bowen, 2002）.
文摘Extracellular polysaccharide from Tremella aurantialba (TEP) significantly inhibited H2O2-induced haemolysis of RBCs, significantly decreased the amount of malondialdehyde (MDA) produced in mice liver homogenates as a result of autoxidation, and inhibited VitC-Fe2+-induced swelling of liver mitochondria.
文摘The rough crystal of exopolysaccharide produced by Enterococcus durans, a strain of lactic acid bacteria screened from the intestine of a cock in our laboratory, was purified by CM-cellulose column chromatography, DEAE-Sephadex A-25 ionexchange and Sephadex G-100 gel chromatography to give EPS-Ⅰ. The EPS-Ⅰ was eluted as a single peak in HPLC analysis, indicating the homogeneity of EPS-Ⅰ and free from low-molecular-weight polysaccharides. The molecular weight of the EPS-Ⅰ was determined as 42 000 by the light scattering method. The result of its elemental analysis was C 41.08% and H 7.23% without the elements of N, P and S. Monosaccharide analysis showed that it was composed of Glc and Man in a molar ratio of 4∶1. Sugar composition analysis, methylation analysis and 1H and 13C NMR spectroscopy revealed that the EPS-Ⅰ was composed of pentasaccharide repeating units. The sequence of sugar residues was determined by using two-dimensional NMR, including heteronuclear multiple-bond correlation(HMBC) and nuclear overhauser effect spectroscopy(NOESY). The structure of the pentasaccharide repeating unit of EPS-Ⅰ was given, a new excellular polysaccharide from lactic acid bacterium compared with other EPSs was reported.
