从四川省成都市青城山采集土壤,以琼脂作为唯一碳源,筛选到产琼脂酶细菌CMCK136;通过形态观察、生化鉴定、16S r DNA测序及序列分析鉴定其种属;随后测定了菌株CMCK136的胞外酶活性。菌株CMCK136被鉴定为芽胞杆菌属细菌,命名为Bacillus s...从四川省成都市青城山采集土壤,以琼脂作为唯一碳源,筛选到产琼脂酶细菌CMCK136;通过形态观察、生化鉴定、16S r DNA测序及序列分析鉴定其种属;随后测定了菌株CMCK136的胞外酶活性。菌株CMCK136被鉴定为芽胞杆菌属细菌,命名为Bacillus sp.CMCK136。菌株CMCK136的胞外琼脂酶的最适酸碱度为p H 7.0,最适温度为35℃。菌株CMCK136是产琼脂酶细菌家族的新成员,该菌株的发现进一步提示芽胞杆菌属很可能蕴含有尚待开发的琼脂酶资源。展开更多
Depolymerization of agar was performed using agarase, which was extracted from the cell-free medium of a culture of marine bacterial Alterornonas sp. nov. SY 37-12. After ethanol fractionation and lyophilization, the ...Depolymerization of agar was performed using agarase, which was extracted from the cell-free medium of a culture of marine bacterial Alterornonas sp. nov. SY 37-12. After ethanol fractionation and lyophilization, the water-soluble agar polysaccharide （WSAP3） was collected. The anti-tumor activity of the product was determined by using Sarcoma 180 tumor in mouse. The tumor inhibition rate of WSAP3 the product was determined by using Sarcoma 180 tumor in mouse. The tumor inhibition rate of WSAP3 reached 48.7% at a dose of 64mg kg^-1 after 15 days treatment. WSAP3 enhanced the aetivities of superoxide dismutase and catalase, which suggests that WSAP3 was effective in promoting the antioxidation ability and eliminating danger from free radicals. The result of flow cytometry showed that the WSAP3 had no activities of cell cycle inhibition or apoptosis-inducing activities. The anti-oxidation of WSAP3 was further confirmed by test in vitro, which might play an important role in anti-tumor activity. The immunological regulation of WSAP3, especially its effect on the phagocytosis ratio and phagocytosis index of rophage was also assayed in test in vivo.展开更多
An agar-degrading bacterium, designated as Pseudoalteromonas sp. NJ21, was isolated from an Antarctic sediment sample. The agarase gene aga1161 from Pseudoalteromonas sp. NJ21 consisting of a 2 382-bp coding region wa...An agar-degrading bacterium, designated as Pseudoalteromonas sp. NJ21, was isolated from an Antarctic sediment sample. The agarase gene aga1161 from Pseudoalteromonas sp. NJ21 consisting of a 2 382-bp coding region was cloned. The gene encodes a 793-amino acids protein and was found to possess characteristic features of the Glyco_hydro 42 family. The recombinant agarase （rAgal 161） was overexpressed in Escherichia coli and purified as a fusion protein. Enzyme activity analysis revealed that the optimum temperature and pH for the purified recombinant agarase were 30--40℃ and 8.0, respectively. rAga 1161 was found to maintain as much as 80% of its maximum activity at 10℃, which is typical of a cold- adapted enzyme. The pattern of agar hydrolysis demonstrated that the enzyme is an β-agarase, producing neoagarobiose （NA2） as the final main product. Furthermore, this work is the first proof of an agarolytic activity in Antarctic bacteria and these results indicate the potential for the Antarctic agarase as a catalyst in medicine, food and cosmetic industries.展开更多
Penicillium simplicissimum was cultured and preserved on the potato dextrose agar(PDA)medium.PDA-RBBR(Remazal Brilliant Blue R)medium was used for the screening of the strains,which is able to produce enzymes.After th...Penicillium simplicissimum was cultured and preserved on the potato dextrose agar(PDA)medium.PDA-RBBR(Remazal Brilliant Blue R)medium was used for the screening of the strains,which is able to produce enzymes.After the mutation process in Penicillium simplicissimum induced by chemical reagent and ultraviolet radiation,a high laccase-producing strains Penicillium simplicissimum was obtained.When 5 m L diethyl sulfate(2%)was mixed along with 5 m L spore suspension for 30 min,chemical mutagenesis reached its best condition.And the optimum conditions of UV mutagenesis were that spore suspension was irradiated for 4 min under 15 W UV lamp at a distance of 30 cm.The highest activity of C_5E_4 strains was 4.80 U/g over 18%higher than the maximum laccase activity of original microorganism.Five generations of the mutant strains were cultured,and the laccase activity of the strains was measured.The result showed that C_5E_4 strains can product laccase of the five subcultures stably.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
AIM： TO determine whether -1195 A→G and/or -765 G→C polymorphisms in Cyclooxygenase-2 CCOX-2） may have a risk modifying effect on the development of esophageal carcinoma in a Dutch Caucasian population. METHODS： ...AIM： TO determine whether -1195 A→G and/or -765 G→C polymorphisms in Cyclooxygenase-2 CCOX-2） may have a risk modifying effect on the development of esophageal carcinoma in a Dutch Caucasian population. METHODS： Two study groups were recruited, 252 patients with esophageal carcinoma and 240 healthy controls, matched for race, age, gender and recruiting area. DNA was isolated from whole blood and used for genotyping. PCR products were digested with restriction enzymes and products were analyzed by agarose gel electrophoresis. Odds ratios （OR） and 95% confidence intervals （CI） were estimated. RESULTS： The distribution of the -1195A→G polymorphism was significantly different in esophageal cancer patients compared to controls. The -1195 GG genotype resulted in a higher risk of developing esophageal adenocarcinoma （OR = 3.85, 95% CI： 1.45-10.3） compared with the -1195AA genotype as a reference. The -765 G→C genotype distribution was not different between the two groups. The GG/ GG haplotype was present more often in esophageal adenocarcinoma patients than in controls （OR = 3.45, 95% CI： 1.24-9.58; with AG/AG as a reference）. The same trends were observed in patients with squamous cell carcinomas, however, the results did not reach statistical significance. CONCLUSION： Presence of the COX-2 -1195 GG genotype and of the GG/GG haplotype may result in a higher risk of developing esophageal carcinoma.展开更多
A growth experiment on agar medium and a hydroponics experiment were carried out to study the nitrogen （N） metabolism of a low-N tolerant mutant （lntl） of Arabidopsis thaliana under different N levels as compared ...A growth experiment on agar medium and a hydroponics experiment were carried out to study the nitrogen （N） metabolism of a low-N tolerant mutant （lntl） of Arabidopsis thaliana under different N levels as compared with the wild- type （WT） Arabidopsis. On the agar medium, no apparent growth differences were observed between the lntl and WT plants under a normal N level of 9 mmol L^-1 NO3. However, under a low N level of 0.18 mmol L^-1 NO3^-, the growth of the WT plants was greatly retarded, while the lntl plants were not affected by low-N stress and showed similar growth with those grown under a normal N level. In the hydroponics experiment, the lntl mutant had higher activities of glutamine synthetase （GS） and NADH-dependent glutamate synthase （NADH-GOGAT） in both leaves and roots under N-deficient conditions. Moreover, they accumulated less ammonium （NH4^＋） but more free amino acids in leaves compared with the WT plants. These observations suggest that better N assimilation might contribute to the low-N tolerant phenotype of the lnt1 mutant.展开更多
文摘从四川省成都市青城山采集土壤,以琼脂作为唯一碳源,筛选到产琼脂酶细菌CMCK136;通过形态观察、生化鉴定、16S r DNA测序及序列分析鉴定其种属;随后测定了菌株CMCK136的胞外酶活性。菌株CMCK136被鉴定为芽胞杆菌属细菌,命名为Bacillus sp.CMCK136。菌株CMCK136的胞外琼脂酶的最适酸碱度为p H 7.0,最适温度为35℃。菌株CMCK136是产琼脂酶细菌家族的新成员,该菌株的发现进一步提示芽胞杆菌属很可能蕴含有尚待开发的琼脂酶资源。
文摘Depolymerization of agar was performed using agarase, which was extracted from the cell-free medium of a culture of marine bacterial Alterornonas sp. nov. SY 37-12. After ethanol fractionation and lyophilization, the water-soluble agar polysaccharide （WSAP3） was collected. The anti-tumor activity of the product was determined by using Sarcoma 180 tumor in mouse. The tumor inhibition rate of WSAP3 the product was determined by using Sarcoma 180 tumor in mouse. The tumor inhibition rate of WSAP3 reached 48.7% at a dose of 64mg kg^-1 after 15 days treatment. WSAP3 enhanced the aetivities of superoxide dismutase and catalase, which suggests that WSAP3 was effective in promoting the antioxidation ability and eliminating danger from free radicals. The result of flow cytometry showed that the WSAP3 had no activities of cell cycle inhibition or apoptosis-inducing activities. The anti-oxidation of WSAP3 was further confirmed by test in vitro, which might play an important role in anti-tumor activity. The immunological regulation of WSAP3, especially its effect on the phagocytosis ratio and phagocytosis index of rophage was also assayed in test in vivo.
基金Supported by the Public Science and Technology Research Funds Project of Ocean(No.201105027)the Shandong Province Young and the Middle-Aged Scientists Research Awards Fund(No.DS2010HZ001)the Basic Scientific Research Funds of First Institute of Oceanography,State Oceanic Administration(No.GY02-2011G17)
文摘An agar-degrading bacterium, designated as Pseudoalteromonas sp. NJ21, was isolated from an Antarctic sediment sample. The agarase gene aga1161 from Pseudoalteromonas sp. NJ21 consisting of a 2 382-bp coding region was cloned. The gene encodes a 793-amino acids protein and was found to possess characteristic features of the Glyco_hydro 42 family. The recombinant agarase （rAgal 161） was overexpressed in Escherichia coli and purified as a fusion protein. Enzyme activity analysis revealed that the optimum temperature and pH for the purified recombinant agarase were 30--40℃ and 8.0, respectively. rAga 1161 was found to maintain as much as 80% of its maximum activity at 10℃, which is typical of a cold- adapted enzyme. The pattern of agar hydrolysis demonstrated that the enzyme is an β-agarase, producing neoagarobiose （NA2） as the final main product. Furthermore, this work is the first proof of an agarolytic activity in Antarctic bacteria and these results indicate the potential for the Antarctic agarase as a catalyst in medicine, food and cosmetic industries.
基金Projects(51178172,51308076,51408206,51578222)supported by the National Natural Science Foundation of ChinaProject(113049A)supported by the Ministry of Education of China
文摘Penicillium simplicissimum was cultured and preserved on the potato dextrose agar(PDA)medium.PDA-RBBR(Remazal Brilliant Blue R)medium was used for the screening of the strains,which is able to produce enzymes.After the mutation process in Penicillium simplicissimum induced by chemical reagent and ultraviolet radiation,a high laccase-producing strains Penicillium simplicissimum was obtained.When 5 m L diethyl sulfate(2%)was mixed along with 5 m L spore suspension for 30 min,chemical mutagenesis reached its best condition.And the optimum conditions of UV mutagenesis were that spore suspension was irradiated for 4 min under 15 W UV lamp at a distance of 30 cm.The highest activity of C_5E_4 strains was 4.80 U/g over 18%higher than the maximum laccase activity of original microorganism.Five generations of the mutant strains were cultured,and the laccase activity of the strains was measured.The result showed that C_5E_4 strains can product laccase of the five subcultures stably.
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AIM： TO determine whether -1195 A→G and/or -765 G→C polymorphisms in Cyclooxygenase-2 CCOX-2） may have a risk modifying effect on the development of esophageal carcinoma in a Dutch Caucasian population. METHODS： Two study groups were recruited, 252 patients with esophageal carcinoma and 240 healthy controls, matched for race, age, gender and recruiting area. DNA was isolated from whole blood and used for genotyping. PCR products were digested with restriction enzymes and products were analyzed by agarose gel electrophoresis. Odds ratios （OR） and 95% confidence intervals （CI） were estimated. RESULTS： The distribution of the -1195A→G polymorphism was significantly different in esophageal cancer patients compared to controls. The -1195 GG genotype resulted in a higher risk of developing esophageal adenocarcinoma （OR = 3.85, 95% CI： 1.45-10.3） compared with the -1195AA genotype as a reference. The -765 G→C genotype distribution was not different between the two groups. The GG/ GG haplotype was present more often in esophageal adenocarcinoma patients than in controls （OR = 3.45, 95% CI： 1.24-9.58; with AG/AG as a reference）. The same trends were observed in patients with squamous cell carcinomas, however, the results did not reach statistical significance. CONCLUSION： Presence of the COX-2 -1195 GG genotype and of the GG/GG haplotype may result in a higher risk of developing esophageal carcinoma.
基金Supported by the National Basic Research Program of China(No.2007CB109305)the National Natural Science Foundation of China(No.30370839)
文摘A growth experiment on agar medium and a hydroponics experiment were carried out to study the nitrogen （N） metabolism of a low-N tolerant mutant （lntl） of Arabidopsis thaliana under different N levels as compared with the wild- type （WT） Arabidopsis. On the agar medium, no apparent growth differences were observed between the lntl and WT plants under a normal N level of 9 mmol L^-1 NO3. However, under a low N level of 0.18 mmol L^-1 NO3^-, the growth of the WT plants was greatly retarded, while the lntl plants were not affected by low-N stress and showed similar growth with those grown under a normal N level. In the hydroponics experiment, the lntl mutant had higher activities of glutamine synthetase （GS） and NADH-dependent glutamate synthase （NADH-GOGAT） in both leaves and roots under N-deficient conditions. Moreover, they accumulated less ammonium （NH4^＋） but more free amino acids in leaves compared with the WT plants. These observations suggest that better N assimilation might contribute to the low-N tolerant phenotype of the lnt1 mutant.
