Lead(Pb(Ⅱ))contamination in soil,primarily resulting from mining and agricultural practices,poses environmental and agricultural challenges due to its toxicity and persistence.This study investigated the potential of...Lead(Pb(Ⅱ))contamination in soil,primarily resulting from mining and agricultural practices,poses environmental and agricultural challenges due to its toxicity and persistence.This study investigated the potential of a phosphate solubilizing bacterium(PSB),Enterobacter hormaechei KR2215,isolated from mangrove rhizosphere,for Pb(Ⅱ)remediation and enhancement of Cicer arietinum(chickpea)growth under Pb(Ⅱ)stress.The strain tolerated Pb(Ⅱ)upto 1900 ppm and achieved 93.86%removal in biofilm mode.Biochemical analysis of extracellular polymeric substances(EPS)revealed reduction in carbohydrate content,while protein and lipid levels increased,under Pb(Ⅱ)stress.Electron microscopy coupled with elemental mapping confirmed Pb(Ⅱ)accumulation on the biofilm-EPS matrix,while structural analysis revealed alterations in EPS functional groups upon Pb(Ⅱ)exposure.EPS protein conformation shifted from α-helix(20.2%)to random coil(51.1%)at 1500 ppm Pb(Ⅱ).Phosphate solubilization(682.83±14.26 U m/L)and acid phosphatase activity(46.67±3.39 U m/L)peaked on 3rd day,but declined at higher Pb(Ⅱ)levels.Gene expression analysis indicated upregulation of phoR,pqqE,pgaC,and wzc at 500 ppm,while zntA expression peaked at 1000 ppm(17.82 fold,P<0.0001).Colonization of E.hormaechei KR2215 in the chickpea endorhizosphere was confirmed by scanning electron microscopy(SEM)and enterobacterial repetitive intergenic sequence-based polymerase chain reaction(ERIC-PCR).Inoculated plants exhibited improved growth and reduced Pb(Ⅱ)accumulation in roots(12.18%),shoots(26.81%),leaves(33.30%),and seeds(42.83%).Additionally,it enhanced antioxidant activity and reduced lipid peroxidation,suggesting its potential to improve crop productivity in Pb(Ⅱ)-contaminated soils.展开更多
Nucleoside phosphorylases (NPases) were found to be induced in Enterobacter aerogenes DGO-04, and cytidine and cytidine 5′-monophosphate (CMP) were the best inducers. Five mmol/L to fifteen mmol/L cytidine or CMP cou...Nucleoside phosphorylases (NPases) were found to be induced in Enterobacter aerogenes DGO-04, and cytidine and cytidine 5′-monophosphate (CMP) were the best inducers. Five mmol/L to fifteen mmol/L cytidine or CMP could distinctly increase the activities of purine nucleoside phosphorylase (PNPase), uridine phosphorylase (UPase) and thymidine phosphorylase (TPase) when they were added into medium from 0 to 8 h. In the process of enzymatic synthesis of adenine arabinoside from adenine and uracil arabinoside with wet cells of Enterobacter aerogenes DGO-04 induced by cytidine or CMP, the reaction time could be shortened from 36 to 6 h. After enzymatic reaction the activity of NPase in the cells induced remained higher than that in the cells uninduced.展开更多
BACKGROUND: Sepsis due to Enterobacter aerogenes (E. aerogenes) is rare after liver transplantation but is also a serious infection that may cause liver abscess. The purpose of this case report is to relate an unusual...BACKGROUND: Sepsis due to Enterobacter aerogenes (E. aerogenes) is rare after liver transplantation but is also a serious infection that may cause liver abscess. The purpose of this case report is to relate an unusual presentation of liver transplantation to show how successive treatment can be an appropriate option in septic patients after liver transplantation. METHOD: We report on a patient with liver transplantation who developed sepsis due to extended spectrum beta-lactamases and AmpC-producing E. aerogenes. RESULTS: A 39-year-old man had a biliary fistula and then was found to have multiple liver abscesses through abdominal ultrasound and an abdominal computed tomography scan, and carbapenem-sensitive E. aerogenes infection was confirmed. The patient was not successfully treated with conservative treatment consisting of intravenous carbapenems, percutaneous transhepatic cholangial drainage, and biliary stent placement by endoscopic retrograde cholangiopancreatography, so a second liver transplantation followed. Carbapenem-resistant E. aerogenes was detected in bile and blood after a five-week course of carbapenem therapy. The patient developed septic shock and multiple organ dysfunction syndrome. CONCLUSIONS: We first report an unusual case of sepsis caused by E. aerogenes after liver transplantation in China. Carbapenem-resistant E. aerogenes finally leads to uncontrolled sepsis with current antibiotics. We hypothesize that the infection developed as a result of biliary fistula and predisposing immunosuppressive agent therapy. Further research is progressing on the aspect of immunomodulation therapy. (Hepatobiliary Pancreat Dis Int 2009; 8: 320-322)展开更多
A bacteria strain for the degradation of hydrolyzed polyacrylamide (HPAM) was isolated from a curing pot in HPAM distribution station of Daqing Oilfield using Hungate anaerobic technique. The isolate was investigate...A bacteria strain for the degradation of hydrolyzed polyacrylamide (HPAM) was isolated from a curing pot in HPAM distribution station of Daqing Oilfield using Hungate anaerobic technique. The isolate was investigated from morphological, physiological, biochemical and molecular characterization. It is a Gram-negative, shortbacillus, non-spore-forming anaerobic bacteria with an optimum growth at 8.0 pH at 40℃. It can reduce sulfate to I-I2S. Alignment of 16S ribosomal DNA and 16S-23S ribosomal DNA intergenic spacer sequences suggests that this isolate is closely related to the Enterobacter cloacae. The isolate is identified as a new strain belonging to Enterobacter genus, temporarily named as Enterobacter cloacae 17. Analysis results of infrared spectroscopy (IR) show that the bacteria can use HPAM as the only carbon source, change the structure of HPAM polymer surface, and realize the hydrolysis of amide to carboxyl group by hydrolysis mechanism. It can degrade the side chain and change some functional groups, which obviously decreases the viscosity. GC-MS analysis indicates that the determined low-molecular weight degradation products of HPAM are polyacrylamide fragments with duplet bond, epoxy as well as carbonyl group, but most of them are acrylamide oligomer derivatives.展开更多
AIM: To identify the gene (s) related to the antagonistic activity of Enterobacter cloacae B8 and to elucidate its antagonistic mechanism. METHODS: Transposon-mediated mutagenesis and tagging method and cassette P...AIM: To identify the gene (s) related to the antagonistic activity of Enterobacter cloacae B8 and to elucidate its antagonistic mechanism. METHODS: Transposon-mediated mutagenesis and tagging method and cassette PCR-based chromosomal walking method were adopted to isolate the mutant strain (s) of B8 that lost the antagonistic activity and to clone DNA fragments around Tn5 insertion site. Sequence compiling and open reading frame (ORF) finding were done with DNAStar program and homologous sequence and conserved domain searches were performed with BlastN or BlastP programs at www.ncbi.nlm.nih.gov. To verify the gene involved in the antagonistic activity, complementation of a full-length clone of the anrFgene to the mutant B8F strain was used. RESULTS: A 3 321 bp contig around the Tn5 insertion site was obtained and an ORF of 2 634 bp in length designated as anrFgene encoding for a 877 aa polyketide synthase-like protein was identified. It had a homology of 83% at the nucleotide level and 79% ID/87% SIM at the protein level, to the admM gene of Pantoea agglomerans andrimid biosynthetic gene cluster (AY192157). The Tn5 was inserted at 2 420 bp of the gene corresponding to the COG3319 (the thioesterase domain of type I polyketide synthase) coding region on BSF. The antagonistic activity against Xanthomonas oryzae pv. oryzae was resumed with complementation of the full-length anrFgene to the mutant B8F. CONCLUSION: The anrFgene obtained is related to the antagonistic activity of BS, and the antagonistic substances produced by B8 are andrimid and/or its analogs.展开更多
Enterobacter GY-1 gained from a lab scale anaerobic-anoxic-aerobic (A2O) process treating textile effluent can effectively decolorize remazol dye. Under anaerobic condition, 91% of this remazol dye is decolorized, whi...Enterobacter GY-1 gained from a lab scale anaerobic-anoxic-aerobic (A2O) process treating textile effluent can effectively decolorize remazol dye. Under anaerobic condition, 91% of this remazol dye is decolorized, which is much higher than under aerobic condition. The optimum pH is 7 and the optimum temperature is 35 ℃ for the remazol dye decolorization by GY-1. Anthraquinone dyes and monoazo dyes are decolorized more efficiently by GY-1 than other dyes tested decolorized. GY-1 can not decolorize the remazol dye when it is the sole carbon source. Microbial cometabolism and decolorization of dye take place in the presence of some other carbon source called cometabolic substrate. The cometabolic substrate can be glucose, starch, peptone, beef extract, etc. The change of molecular structure of the dye before and after decolorized by GY-1 is studied by UV-Vis absorption spectrum. The results indicate that its molecular structure is changed evidently.展开更多
Contamination of agricultural soils by heavy metals has become a major concern due to their toxic effects on plant growth,symbiosis and consequently the yields of crops. In the present study, to enhance plant growth i...Contamination of agricultural soils by heavy metals has become a major concern due to their toxic effects on plant growth,symbiosis and consequently the yields of crops. In the present study, to enhance plant growth in Cr(VI)-amended soils, novel metalresistant plant growth-promoting bacteria(PGPB) were isolated from a soil contaminated with industrial waste effluent. One of the bacterial isolates, identified as Enterobacter sp. C1 D by 16 S r RNA gene sequencing, was found to be multi-metal resistant in nature with excellent plant growth-promoting(PGP) traits. Mung bean(Vigna radiata var. GM4) inoculation with Enterobacter sp.C1 D significantly(P &lt; 0.01) increased root and shoot length, shoot and root weight, and chlorophyll content in a range of Cr(VI)treatments. Plant tolerance towards Cr(VI) measured as effective concentration showed higher values with Enterobacter sp. C1 Dtreated plants compared to un-inoculated plants. Root colonization study was also carried out using green fluorescence protein-labeled Enterobacter sp. C1 D under a hydroponic system. Confocal laser scanning microscopy of the plant roots showed heavy bacterial loads on the surface of the plant root specifically at the root tip and the point of root hair/lateral root formation. The results of PGP traits showed that elevated indole acetic acid levels and 1-aminocyclopropane-1-carboxylate deaminase activity enabled Enterobacter sp. C1 D to enhance V. radiata growth in Cr(VI)-amended soils, whereby it significantly increased plant tolerance towards elevated Cr(VI) concentrations.展开更多
基金the Council of Scientific&Industrial Research(CSIR),India,for the financial support(No.38(1517)/21/EMR-II).
摘要Lead(Pb(Ⅱ))contamination in soil,primarily resulting from mining and agricultural practices,poses environmental and agricultural challenges due to its toxicity and persistence.This study investigated the potential of a phosphate solubilizing bacterium(PSB),Enterobacter hormaechei KR2215,isolated from mangrove rhizosphere,for Pb(Ⅱ)remediation and enhancement of Cicer arietinum(chickpea)growth under Pb(Ⅱ)stress.The strain tolerated Pb(Ⅱ)upto 1900 ppm and achieved 93.86%removal in biofilm mode.Biochemical analysis of extracellular polymeric substances(EPS)revealed reduction in carbohydrate content,while protein and lipid levels increased,under Pb(Ⅱ)stress.Electron microscopy coupled with elemental mapping confirmed Pb(Ⅱ)accumulation on the biofilm-EPS matrix,while structural analysis revealed alterations in EPS functional groups upon Pb(Ⅱ)exposure.EPS protein conformation shifted from α-helix(20.2%)to random coil(51.1%)at 1500 ppm Pb(Ⅱ).Phosphate solubilization(682.83±14.26 U m/L)and acid phosphatase activity(46.67±3.39 U m/L)peaked on 3rd day,but declined at higher Pb(Ⅱ)levels.Gene expression analysis indicated upregulation of phoR,pqqE,pgaC,and wzc at 500 ppm,while zntA expression peaked at 1000 ppm(17.82 fold,P<0.0001).Colonization of E.hormaechei KR2215 in the chickpea endorhizosphere was confirmed by scanning electron microscopy(SEM)and enterobacterial repetitive intergenic sequence-based polymerase chain reaction(ERIC-PCR).Inoculated plants exhibited improved growth and reduced Pb(Ⅱ)accumulation in roots(12.18%),shoots(26.81%),leaves(33.30%),and seeds(42.83%).Additionally,it enhanced antioxidant activity and reduced lipid peroxidation,suggesting its potential to improve crop productivity in Pb(Ⅱ)-contaminated soils.
基金Project (No. 07C26213101283) supported by the Innovation Fundfor Technology Based Firms from the Ministry of Science andTechnology of China
摘要Nucleoside phosphorylases (NPases) were found to be induced in Enterobacter aerogenes DGO-04, and cytidine and cytidine 5′-monophosphate (CMP) were the best inducers. Five mmol/L to fifteen mmol/L cytidine or CMP could distinctly increase the activities of purine nucleoside phosphorylase (PNPase), uridine phosphorylase (UPase) and thymidine phosphorylase (TPase) when they were added into medium from 0 to 8 h. In the process of enzymatic synthesis of adenine arabinoside from adenine and uracil arabinoside with wet cells of Enterobacter aerogenes DGO-04 induced by cytidine or CMP, the reaction time could be shortened from 36 to 6 h. After enzymatic reaction the activity of NPase in the cells induced remained higher than that in the cells uninduced.
摘要BACKGROUND: Sepsis due to Enterobacter aerogenes (E. aerogenes) is rare after liver transplantation but is also a serious infection that may cause liver abscess. The purpose of this case report is to relate an unusual presentation of liver transplantation to show how successive treatment can be an appropriate option in septic patients after liver transplantation. METHOD: We report on a patient with liver transplantation who developed sepsis due to extended spectrum beta-lactamases and AmpC-producing E. aerogenes. RESULTS: A 39-year-old man had a biliary fistula and then was found to have multiple liver abscesses through abdominal ultrasound and an abdominal computed tomography scan, and carbapenem-sensitive E. aerogenes infection was confirmed. The patient was not successfully treated with conservative treatment consisting of intravenous carbapenems, percutaneous transhepatic cholangial drainage, and biliary stent placement by endoscopic retrograde cholangiopancreatography, so a second liver transplantation followed. Carbapenem-resistant E. aerogenes was detected in bile and blood after a five-week course of carbapenem therapy. The patient developed septic shock and multiple organ dysfunction syndrome. CONCLUSIONS: We first report an unusual case of sepsis caused by E. aerogenes after liver transplantation in China. Carbapenem-resistant E. aerogenes finally leads to uncontrolled sepsis with current antibiotics. We hypothesize that the infection developed as a result of biliary fistula and predisposing immunosuppressive agent therapy. Further research is progressing on the aspect of immunomodulation therapy. (Hepatobiliary Pancreat Dis Int 2009; 8: 320-322)
基金Sponsored by the Country from Branch Fund Significant International Cooperation Item(Grant No.50521140075)
摘要A bacteria strain for the degradation of hydrolyzed polyacrylamide (HPAM) was isolated from a curing pot in HPAM distribution station of Daqing Oilfield using Hungate anaerobic technique. The isolate was investigated from morphological, physiological, biochemical and molecular characterization. It is a Gram-negative, shortbacillus, non-spore-forming anaerobic bacteria with an optimum growth at 8.0 pH at 40℃. It can reduce sulfate to I-I2S. Alignment of 16S ribosomal DNA and 16S-23S ribosomal DNA intergenic spacer sequences suggests that this isolate is closely related to the Enterobacter cloacae. The isolate is identified as a new strain belonging to Enterobacter genus, temporarily named as Enterobacter cloacae 17. Analysis results of infrared spectroscopy (IR) show that the bacteria can use HPAM as the only carbon source, change the structure of HPAM polymer surface, and realize the hydrolysis of amide to carboxyl group by hydrolysis mechanism. It can degrade the side chain and change some functional groups, which obviously decreases the viscosity. GC-MS analysis indicates that the determined low-molecular weight degradation products of HPAM are polyacrylamide fragments with duplet bond, epoxy as well as carbonyl group, but most of them are acrylamide oligomer derivatives.
基金Supported by the National Natural Science Foundation of China,No. 39870034the National High Technology Research and Development Program of China, the 863 Program, No. 104-04-01-01the Major Project of Science and Technology Development of Zhejiang Province, No. 021102529
摘要AIM: To identify the gene (s) related to the antagonistic activity of Enterobacter cloacae B8 and to elucidate its antagonistic mechanism. METHODS: Transposon-mediated mutagenesis and tagging method and cassette PCR-based chromosomal walking method were adopted to isolate the mutant strain (s) of B8 that lost the antagonistic activity and to clone DNA fragments around Tn5 insertion site. Sequence compiling and open reading frame (ORF) finding were done with DNAStar program and homologous sequence and conserved domain searches were performed with BlastN or BlastP programs at www.ncbi.nlm.nih.gov. To verify the gene involved in the antagonistic activity, complementation of a full-length clone of the anrFgene to the mutant B8F strain was used. RESULTS: A 3 321 bp contig around the Tn5 insertion site was obtained and an ORF of 2 634 bp in length designated as anrFgene encoding for a 877 aa polyketide synthase-like protein was identified. It had a homology of 83% at the nucleotide level and 79% ID/87% SIM at the protein level, to the admM gene of Pantoea agglomerans andrimid biosynthetic gene cluster (AY192157). The Tn5 was inserted at 2 420 bp of the gene corresponding to the COG3319 (the thioesterase domain of type I polyketide synthase) coding region on BSF. The antagonistic activity against Xanthomonas oryzae pv. oryzae was resumed with complementation of the full-length anrFgene to the mutant B8F. CONCLUSION: The anrFgene obtained is related to the antagonistic activity of BS, and the antagonistic substances produced by B8 are andrimid and/or its analogs.
基金Fundamental Research Funds for the Central Universities of China(No.2011D11309)Shanghai Leading Academic Discipline,China(No.B604)
摘要Enterobacter GY-1 gained from a lab scale anaerobic-anoxic-aerobic (A2O) process treating textile effluent can effectively decolorize remazol dye. Under anaerobic condition, 91% of this remazol dye is decolorized, which is much higher than under aerobic condition. The optimum pH is 7 and the optimum temperature is 35 ℃ for the remazol dye decolorization by GY-1. Anthraquinone dyes and monoazo dyes are decolorized more efficiently by GY-1 than other dyes tested decolorized. GY-1 can not decolorize the remazol dye when it is the sole carbon source. Microbial cometabolism and decolorization of dye take place in the presence of some other carbon source called cometabolic substrate. The cometabolic substrate can be glucose, starch, peptone, beef extract, etc. The change of molecular structure of the dye before and after decolorized by GY-1 is studied by UV-Vis absorption spectrum. The results indicate that its molecular structure is changed evidently.
基金supported by the Department of Science and Technology (DST), Government of India (No. SR/S4/ES-21/Baroda Window/P3)
摘要Contamination of agricultural soils by heavy metals has become a major concern due to their toxic effects on plant growth,symbiosis and consequently the yields of crops. In the present study, to enhance plant growth in Cr(VI)-amended soils, novel metalresistant plant growth-promoting bacteria(PGPB) were isolated from a soil contaminated with industrial waste effluent. One of the bacterial isolates, identified as Enterobacter sp. C1 D by 16 S r RNA gene sequencing, was found to be multi-metal resistant in nature with excellent plant growth-promoting(PGP) traits. Mung bean(Vigna radiata var. GM4) inoculation with Enterobacter sp.C1 D significantly(P &lt; 0.01) increased root and shoot length, shoot and root weight, and chlorophyll content in a range of Cr(VI)treatments. Plant tolerance towards Cr(VI) measured as effective concentration showed higher values with Enterobacter sp. C1 Dtreated plants compared to un-inoculated plants. Root colonization study was also carried out using green fluorescence protein-labeled Enterobacter sp. C1 D under a hydroponic system. Confocal laser scanning microscopy of the plant roots showed heavy bacterial loads on the surface of the plant root specifically at the root tip and the point of root hair/lateral root formation. The results of PGP traits showed that elevated indole acetic acid levels and 1-aminocyclopropane-1-carboxylate deaminase activity enabled Enterobacter sp. C1 D to enhance V. radiata growth in Cr(VI)-amended soils, whereby it significantly increased plant tolerance towards elevated Cr(VI) concentrations.