[Objective] The aim was to explore the relationship between alage-lysing bacterium and Anabaena flosaquae so as to provide reference for the control of bloom. [Method] An algae-lysing bacterium strain named S7 was iso...[Objective] The aim was to explore the relationship between alage-lysing bacterium and Anabaena flosaquae so as to provide reference for the control of bloom. [Method] An algae-lysing bacterium strain named S7 was isolated from eu- trophic river. The lyric efficiency and performing mode of S7 strain to Anabaena flos- aquae was studied. Influence of different environmental factors and the relationship between S7 strain and Anabaena flosaquae was also studied, and then the bacteri- um strain was physiologically identified. [Result] More than 90% of Anabaena flos- aquae had been removed by 7 d when the volume ratio of medium to algae solu- tion was 30%, the pH was 9 and the temperature was 35 ℃. These results also showed that a mutual inhibit relationship existed between S7 strain and Anabaena flos-aquae. The S7 strain killed the algae by indirectly through certain lyric agents in absence of direct contact with the target but by secreting metabolites. Moreover, these lyric agents also had the thermostability. 16SrDNA sequence analysis showed that S7 strain belonged to Chryseobacterium sp. [Conclusion] The examined Poly-p proved that S7 strain is polyphosphate accumulating bacteria （PAOs） and has better lyric efficiency.展开更多
Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacte...Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacterium B5 was isolated from activated sludge. On the basis of analysis of its physiological characteristics and 16S rDNA gene sequence, it was identified as Bacillusfusiformis. Its algaelysing characteristics on Microcystis aeruginosa, Chlorella and Scenedesmus were tested. The results showed that： （1） the algicidal bacterium B5 is a Gram-negative bacterium. The 16S rDNA nucleotide sequence homology of strain B5 with 2 strains of B. fusiformis reached 99.86%, so B5 was identified as B. fusiformis; （2） the algal-lysing effects of the algicidal bacterium B5 on M. aeruginosa, Chlorella and Scenedesrnus were pronounced. The initial bacterial and algal cell densities strongly influence the removal rates of chlorophyll-a. The greater the initial bacterial cell density, the faster the degradation of chlorophyll-a. The greater the initial algal cell density, the slower the degradation of chlorophyll-a. When the bacterial cell density was 3.6 × 10^7 cells/ml, nearly 90% of chlorophyll-a was removed. When the chlorophyll-a concentration was less than 550 μg/L, about 70% was removed; （3） the strain B5 lysed algae by secreting metabolites and these metabolites could bear heat treatment.展开更多
Algae-lysing bacteria A1 has good control effect on the moss through its extracellular secretion. In order to further study its control mechanism, the sin- gle-factor tests of temperature and pH value, the activated c...Algae-lysing bacteria A1 has good control effect on the moss through its extracellular secretion. In order to further study its control mechanism, the sin- gle-factor tests of temperature and pH value, the activated carbon adsorption test, the organic solvent extraction test and the crude extract of active substance test were carried out to explore the characteristics of active substances. The results showed that the algae-lysing active ingredient of A1 strain had strong thermal stabili- ty, which still had good algae-lysing effect after being treated at 121 ℃ ; when the pH values of fermentation liquid were adjusted to 2.0 and 4.0 respectively, the active substances lost their activities, but their control ability against moss would be enhanced under the alkaline conditions ; the active substances could not be ad- sorbed by activated carbon; the algae-lysing active substances showed strong hydrophilie ability when they were extracted by ethyl acetate, petroleum ether and chloroform. Therefore, it could be speculated that the active substances belonged to carbohydrates. The crude extract results of algae-lysing active substances showed that the active substances secreted by A1 strain were composed by a variety of algae-lysing active substances.展开更多
[Objectives]This study was conducted to explore the culture conditions for siderophore production and preliminarily investigate the growth-promoting effects of strains.[Methods]Endophytic bacteria secreting siderophor...[Objectives]This study was conducted to explore the culture conditions for siderophore production and preliminarily investigate the growth-promoting effects of strains.[Methods]Endophytic bacteria secreting siderophores were isolated and screened from the roots of the plant Saposhnikovia divaricata(Trucz.)Schischk.The siderophore-producing capability was confirmed through qualitative detection and gene cluster analysis.[Results]The screened endophytic bacterium PB-2 belonged to the genus Paenibacillus sp.and could produce catechol-type or carboxylate-type siderophores.When cultured in MKB medium with 15 g/L glycerol as the carbon source and 6 g/L glycine as the nitrogen source for 3 d,the strain exhibited efficient siderophore secretion.Appropriate concentrations of Fe^(3+),Co^(2+),Cu^(2+)and Al^(3+)promoted siderophore production,with 15μmol/L Fe^(3+)being the most effective.Under the combined influences of siderophores,volatile compounds and other factors,strain PB-2 altered the root morphology of mulberry seedlings and increased their biomass.The primary root length decreased by 9.15%,while the number and length of root hairs increased by 37.93%and 16.37%,respectively,and the total biomass increased by 10.26%,all showing significant differences(P<0.05).Additionally,strain PB-2 enhanced the activities of defense-related enzymes in mulberry seedling leaves.The activities of superoxide dismutase(SOD)and peroxidase(POD)increased significantly(P<0.05)by 247.27%and 189.47%,respectively,compared with the control group.The activities of phenylalanine ammonialyase(PAL)and polyphenol oxidase(PPO)also showed varying degrees of increase.[Conclusions]This study provided a theoretical basis for rational utilization of endophytic growth-promoting strains secreting siderophores in the sustainable development of agriculture.展开更多
以海南、湖南、四川雪茄烟叶为研究对象,通过16S r DNA和ITS1测序分析不同产区烟叶发酵前后细菌与真菌群落结构及丰度信息,并考察不同产区雪茄烟叶细菌和真菌间相互作用。结果表明,发酵前四川烟叶细菌操作分类单元(OTU)数及α-多样性指...以海南、湖南、四川雪茄烟叶为研究对象,通过16S r DNA和ITS1测序分析不同产区烟叶发酵前后细菌与真菌群落结构及丰度信息,并考察不同产区雪茄烟叶细菌和真菌间相互作用。结果表明,发酵前四川烟叶细菌操作分类单元(OTU)数及α-多样性指数最高,真菌以湖南烟叶最高;发酵后湖南和四川烟叶微生物α-多样性指数均下降。发酵后各产区雪茄烟叶细菌和真菌的共有OTU数均减少,而特有OTU数因产区不同而变化。各产区烟叶发酵前后绝对优势真菌均为曲霉属(Aspergillus);细菌优势菌属则发生显著演替,发酵前湖南、海南和四川产区优势细菌属分别为鞘氨醇单胞菌(Sphingomonas)、金色单胞菌属(Aureimonas)和葡萄球菌属(Staphylococcus),发酵后湖南和四川产区烟叶以Staphylococcus为主,海南产区以假单胞菌属(Pseudomonas)为主。相关性网络分析结果表明,细菌群落的网络规模和复杂性高于真菌,以四川烟叶的细菌网络最复杂且竞争关系突出,而湖南烟叶的真菌网络连接最紧密、结构最稳定。综上,不同产区雪茄烟叶的微生物群落结构与相互作用存在明显差异,发酵可影响其微生物菌群组成及演替规律。展开更多
目的探讨ICU机械通气患者呼吸机相关肺炎(VAP)不同临床结局的危险因素和病原学特征。方法采用回顾性方法,统计分析2020-2023年石河子大学第一附属医院和石河子市人民医院ICU机械通气患者的临床资料。比较VAP与非VAP患者的临床资料,早发...目的探讨ICU机械通气患者呼吸机相关肺炎(VAP)不同临床结局的危险因素和病原学特征。方法采用回顾性方法,统计分析2020-2023年石河子大学第一附属医院和石河子市人民医院ICU机械通气患者的临床资料。比较VAP与非VAP患者的临床资料,早发型与晚发型VAP患者临床结局(存活/死亡)的危险因素及病原菌特征。结果共纳入机械通气患者2020例,发生VAP 125例,VAP发病率为6.19%(125/2020),VAP发生时间平均为插管后6.9 d。VAP组机械通气时间及住院时间长于非VAP组中位时间(14.00 d vs.7.94 d,34.04 d vs.20.95 d,P<0.05),VAP多因素logistic分析结果显示:低蛋白血症(OR=1.832,95%CI:1.224~2.741,P=0.003)、联用抗菌药物(OR=3.073,95%CI:1.096~8.616,P=0.033)、住院期间手术(OR=1.880,95%CI:1.247~2.835,P=0.003)是ICU机械通气患者发生VAP的危险因素。年龄(OR=1.045,95%CI:1.017~1.074,P=0.002)、糖尿病(OR=2.548,95%CI:1.003~6.472,P=0.049)、最高体温(OR=3.156,95%CI:1.385~7.192,P=0.006)是VAP患者死亡的危险因素。VAP组检出291株病原菌,其中革兰阴性菌228株,革兰阳性菌39株,真菌21株;VAP死亡组真菌及多重耐药鲍曼不动杆菌检出率高于生存组(P<0.05)。结论低蛋白血症、联用抗菌药物、住院期间手术是发生VAP的危险因素;年龄、糖尿病、最高体温是VAP患者死亡的危险因素。VAP与患者的机械通气时间及住院时间密切相关。展开更多
基金Supported by Ecological Environment Construction and Protection Demonstration Project of Three Gorges~~
文摘[Objective] The aim was to explore the relationship between alage-lysing bacterium and Anabaena flosaquae so as to provide reference for the control of bloom. [Method] An algae-lysing bacterium strain named S7 was isolated from eu- trophic river. The lyric efficiency and performing mode of S7 strain to Anabaena flos- aquae was studied. Influence of different environmental factors and the relationship between S7 strain and Anabaena flosaquae was also studied, and then the bacteri- um strain was physiologically identified. [Result] More than 90% of Anabaena flos- aquae had been removed by 7 d when the volume ratio of medium to algae solu- tion was 30%, the pH was 9 and the temperature was 35 ℃. These results also showed that a mutual inhibit relationship existed between S7 strain and Anabaena flos-aquae. The S7 strain killed the algae by indirectly through certain lyric agents in absence of direct contact with the target but by secreting metabolites. Moreover, these lyric agents also had the thermostability. 16SrDNA sequence analysis showed that S7 strain belonged to Chryseobacterium sp. [Conclusion] The examined Poly-p proved that S7 strain is polyphosphate accumulating bacteria （PAOs） and has better lyric efficiency.
基金Project supported by the Special Funds for Doctor's Station of University(No.20060246024)Young Fund of Fudan University,and the Shanghai Tongji Gao Tingyao Environmental Science and Technology Developmem Fundation
文摘Water blooms have become a worldwide environmental problem. Recently, algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms. In this study, one strain of algicidal bacterium B5 was isolated from activated sludge. On the basis of analysis of its physiological characteristics and 16S rDNA gene sequence, it was identified as Bacillusfusiformis. Its algaelysing characteristics on Microcystis aeruginosa, Chlorella and Scenedesmus were tested. The results showed that： （1） the algicidal bacterium B5 is a Gram-negative bacterium. The 16S rDNA nucleotide sequence homology of strain B5 with 2 strains of B. fusiformis reached 99.86%, so B5 was identified as B. fusiformis; （2） the algal-lysing effects of the algicidal bacterium B5 on M. aeruginosa, Chlorella and Scenedesrnus were pronounced. The initial bacterial and algal cell densities strongly influence the removal rates of chlorophyll-a. The greater the initial bacterial cell density, the faster the degradation of chlorophyll-a. The greater the initial algal cell density, the slower the degradation of chlorophyll-a. When the bacterial cell density was 3.6 × 10^7 cells/ml, nearly 90% of chlorophyll-a was removed. When the chlorophyll-a concentration was less than 550 μg/L, about 70% was removed; （3） the strain B5 lysed algae by secreting metabolites and these metabolites could bear heat treatment.
基金Supported by Scientific and Technological Research Projects in Suihua University(KQ1002004)~~
文摘Algae-lysing bacteria A1 has good control effect on the moss through its extracellular secretion. In order to further study its control mechanism, the sin- gle-factor tests of temperature and pH value, the activated carbon adsorption test, the organic solvent extraction test and the crude extract of active substance test were carried out to explore the characteristics of active substances. The results showed that the algae-lysing active ingredient of A1 strain had strong thermal stabili- ty, which still had good algae-lysing effect after being treated at 121 ℃ ; when the pH values of fermentation liquid were adjusted to 2.0 and 4.0 respectively, the active substances lost their activities, but their control ability against moss would be enhanced under the alkaline conditions ; the active substances could not be ad- sorbed by activated carbon; the algae-lysing active substances showed strong hydrophilie ability when they were extracted by ethyl acetate, petroleum ether and chloroform. Therefore, it could be speculated that the active substances belonged to carbohydrates. The crude extract results of algae-lysing active substances showed that the active substances secreted by A1 strain were composed by a variety of algae-lysing active substances.
基金Supported by Doctoral Start-up Fund of Jiangsu University of Science and Technology(1102931901).
文摘[Objectives]This study was conducted to explore the culture conditions for siderophore production and preliminarily investigate the growth-promoting effects of strains.[Methods]Endophytic bacteria secreting siderophores were isolated and screened from the roots of the plant Saposhnikovia divaricata(Trucz.)Schischk.The siderophore-producing capability was confirmed through qualitative detection and gene cluster analysis.[Results]The screened endophytic bacterium PB-2 belonged to the genus Paenibacillus sp.and could produce catechol-type or carboxylate-type siderophores.When cultured in MKB medium with 15 g/L glycerol as the carbon source and 6 g/L glycine as the nitrogen source for 3 d,the strain exhibited efficient siderophore secretion.Appropriate concentrations of Fe^(3+),Co^(2+),Cu^(2+)and Al^(3+)promoted siderophore production,with 15μmol/L Fe^(3+)being the most effective.Under the combined influences of siderophores,volatile compounds and other factors,strain PB-2 altered the root morphology of mulberry seedlings and increased their biomass.The primary root length decreased by 9.15%,while the number and length of root hairs increased by 37.93%and 16.37%,respectively,and the total biomass increased by 10.26%,all showing significant differences(P<0.05).Additionally,strain PB-2 enhanced the activities of defense-related enzymes in mulberry seedling leaves.The activities of superoxide dismutase(SOD)and peroxidase(POD)increased significantly(P<0.05)by 247.27%and 189.47%,respectively,compared with the control group.The activities of phenylalanine ammonialyase(PAL)and polyphenol oxidase(PPO)also showed varying degrees of increase.[Conclusions]This study provided a theoretical basis for rational utilization of endophytic growth-promoting strains secreting siderophores in the sustainable development of agriculture.
文摘以海南、湖南、四川雪茄烟叶为研究对象,通过16S r DNA和ITS1测序分析不同产区烟叶发酵前后细菌与真菌群落结构及丰度信息,并考察不同产区雪茄烟叶细菌和真菌间相互作用。结果表明,发酵前四川烟叶细菌操作分类单元(OTU)数及α-多样性指数最高,真菌以湖南烟叶最高;发酵后湖南和四川烟叶微生物α-多样性指数均下降。发酵后各产区雪茄烟叶细菌和真菌的共有OTU数均减少,而特有OTU数因产区不同而变化。各产区烟叶发酵前后绝对优势真菌均为曲霉属(Aspergillus);细菌优势菌属则发生显著演替,发酵前湖南、海南和四川产区优势细菌属分别为鞘氨醇单胞菌(Sphingomonas)、金色单胞菌属(Aureimonas)和葡萄球菌属(Staphylococcus),发酵后湖南和四川产区烟叶以Staphylococcus为主,海南产区以假单胞菌属(Pseudomonas)为主。相关性网络分析结果表明,细菌群落的网络规模和复杂性高于真菌,以四川烟叶的细菌网络最复杂且竞争关系突出,而湖南烟叶的真菌网络连接最紧密、结构最稳定。综上,不同产区雪茄烟叶的微生物群落结构与相互作用存在明显差异,发酵可影响其微生物菌群组成及演替规律。
文摘目的探讨ICU机械通气患者呼吸机相关肺炎(VAP)不同临床结局的危险因素和病原学特征。方法采用回顾性方法,统计分析2020-2023年石河子大学第一附属医院和石河子市人民医院ICU机械通气患者的临床资料。比较VAP与非VAP患者的临床资料,早发型与晚发型VAP患者临床结局(存活/死亡)的危险因素及病原菌特征。结果共纳入机械通气患者2020例,发生VAP 125例,VAP发病率为6.19%(125/2020),VAP发生时间平均为插管后6.9 d。VAP组机械通气时间及住院时间长于非VAP组中位时间(14.00 d vs.7.94 d,34.04 d vs.20.95 d,P<0.05),VAP多因素logistic分析结果显示:低蛋白血症(OR=1.832,95%CI:1.224~2.741,P=0.003)、联用抗菌药物(OR=3.073,95%CI:1.096~8.616,P=0.033)、住院期间手术(OR=1.880,95%CI:1.247~2.835,P=0.003)是ICU机械通气患者发生VAP的危险因素。年龄(OR=1.045,95%CI:1.017~1.074,P=0.002)、糖尿病(OR=2.548,95%CI:1.003~6.472,P=0.049)、最高体温(OR=3.156,95%CI:1.385~7.192,P=0.006)是VAP患者死亡的危险因素。VAP组检出291株病原菌,其中革兰阴性菌228株,革兰阳性菌39株,真菌21株;VAP死亡组真菌及多重耐药鲍曼不动杆菌检出率高于生存组(P<0.05)。结论低蛋白血症、联用抗菌药物、住院期间手术是发生VAP的危险因素;年龄、糖尿病、最高体温是VAP患者死亡的危险因素。VAP与患者的机械通气时间及住院时间密切相关。
