The quantum bacterial foraging optimization(QBFO)algorithm has the characteristics of strong robustness and global searching ability. In the classical QBFO algorithm, the rotation angle updated by the rotation gate is...The quantum bacterial foraging optimization(QBFO)algorithm has the characteristics of strong robustness and global searching ability. In the classical QBFO algorithm, the rotation angle updated by the rotation gate is discrete and constant,which cannot affect the situation of the solution space and limit the diversity of bacterial population. In this paper, an improved QBFO(IQBFO) algorithm is proposed, which can adaptively make the quantum rotation angle continuously updated and enhance the global search ability. In the initialization process, the modified probability of the optimal rotation angle is introduced to avoid the existence of invariant solutions. The modified operator of probability amplitude is adopted to further increase the population diversity.The tests based on benchmark functions verify the effectiveness of the proposed algorithm. Moreover, compared with the integerorder PID controller, the fractional-order proportion integration differentiation(PID) controller increases the complexity of the system with better flexibility and robustness. Thus the fractional-order PID controller is applied to the servo system. The tuning results of PID parameters of the fractional-order servo system show that the proposed algorithm has a good performance in tuning the PID parameters of the fractional-order servo system.展开更多
The utilization of biomimicry of bacterial foraging strategy was considered to develop an adaptive control strategy for mobile robot, and a bacterial foraging approach was proposed for robot path planning. In the prop...The utilization of biomimicry of bacterial foraging strategy was considered to develop an adaptive control strategy for mobile robot, and a bacterial foraging approach was proposed for robot path planning. In the proposed model, robot that mimics the behavior of bacteria is able to determine an optimal collision-free path between a start and a target point in the environment surrounded by obstacles. In the simulation, two test scenarios of static environment with different number obstacles were adopted to evaluate the performance of the proposed method. Simulation results show that the robot which reflects the bacterial foraging behavior can adapt to complex environments in the planned trajectories with both satisfactory accuracy and stability.展开更多
The trail was designed to study on technique aspects of ensiling rice straw （RS） appended amounts of lactobacillus. There were two groups according to silage ways, baled silage （BS） and chopped silage （CS）, in w...The trail was designed to study on technique aspects of ensiling rice straw （RS） appended amounts of lactobacillus. There were two groups according to silage ways, baled silage （BS） and chopped silage （CS）, in which lactobacillus was added at levels of 10, 15 and 20 mg·kg^-1, respectively and the mixtures were placed into a packed polyethylene bags and stored at room temperature for 45 days. The results showed that lactobacillus had remarkable effect on fermentation characteristics of RS. The quality of the silage was improved with the lactobacillus addition. In the experiment the optimal quality of rice straw silage （RSS） can be obtained when lactobacillus was added with 15 or 20 mg·kg^-1 level. The effect of different silage methods was very remarkable to the silage quality of same material. The quality of CS was better than that of long silage, at the same time, BS was feasible on condition of eligible level of lactic acid bacteria.展开更多
Understanding the impacts of co-invasion of multiple invaders on soil bacterial communities is significant in understanding the mechanisms driving successful invasion.This study aimed to determine the response of soil...Understanding the impacts of co-invasion of multiple invaders on soil bacterial communities is significant in understanding the mechanisms driving successful invasion.This study aimed to determine the response of soil bacterial communities to co-invasion of two invaders daisy fleabane(Erigeron annuus)and Canada goldenrod(Solidago canadensis).Daisy fleabane and/or Canada goldenrod invasion significantly enhanced the operational taxonomic unit richness,Shannon index,and Chao1 index of soil bacterial communities.Canada goldenrod under light degree of invasion and co-invasion of daisy fleabane and Canada goldenrod regardless of invasion degree signally improved the ACE index of soil bacterial communities.Thus,the two invaders can enhance soil bacterial diversity and richness to facilitating subsequent invasion due to the fact that higher soil bacterial diversity and richness can enhance the levels of soil function and nutrients acquisition of plant species.ACE index of soil bacterial communities subjected to co-invasion of daisy fleabane and Canada goldenrod regardless of invasion degree was greater than that under the independent invasion of either daisy fleabane or Canada goldenrod.Hence,co-invasion of the two invaders can impose synergistic impacts on soil bacterial richness,which may build a preferable soil micro-environment via the intensified soil bacterial communities,which is contributive to their following invasion.展开更多
To reveal the impact of mining on bacterial ecology around mining area,bacterial community and geochemical characteristics about Dabaoshan Mine(Guangdong Province,China)were studied.By amplified ribosomal DNA restrict...To reveal the impact of mining on bacterial ecology around mining area,bacterial community and geochemical characteristics about Dabaoshan Mine(Guangdong Province,China)were studied.By amplified ribosomal DNA restriction analysis and phylogenetic analysis,it is found that mining pollution greatly impacts the bacterial ecology and makes the habitat type of polluted environments close to acid mine drainage(AMD)ecology.The polluted environment is acidified so greatly that neutrophil and alkaliphilic microbes are massively dead and decomposed.It provided organic matters that can make Acidiphilium sp.rapidly grow and become the most bacterial species in this niche.Furthermore,Acidithiobacillus ferrooxidans and Leptospirillum sp.are also present in this niche.The amount of Leptospirillum sp.is far more than that of Acidithiobacillus ferrooxidans,which indicates that the concentration of toxic ions is very high.The conclusions of biogeochemical analysis and microbiological monitor are identical. Moreover,because the growth of Acidithiobacillus ferrooxidans and Leptospirillum sp.depends on ferrous iron or inorganic redox sulfur compounds which can be supplied by continual AMD,their presence indicates that AMD still flows into the site.And the area is closer to the outfalls of AMD,their biomasses would be more.So the distinction of their biomasses among different areas can help us to find the effluent route of AMD.展开更多
The bacterial pre-oxidation process of arsenic-containing gold concentrates and the bacterial activity under different chloride ion concentrations were studied by using a mixture of thermophilic strains TCJ domesticat...The bacterial pre-oxidation process of arsenic-containing gold concentrates and the bacterial activity under different chloride ion concentrations were studied by using a mixture of thermophilic strains TCJ domesticated in production.The experimental result shows that with different samples and leaching systems,the adaptability and Cl- tolerance of bacteria are different,and that appropriate chloride ion concentration is conductive to bacterial oxidation,while higher chloride ion concentration will inhibit the bacterial activity and affect the pre-oxidation performance.Under the present production conditions,TCJ can adapt to the changes of water quality in the source of water and its critical chloride ion tolerance value is 2.7 g/L.展开更多
Aim To research therapeutical effect of marine lysozyme suppository on bacterial vaginitis caused by S. aureus and E. coll. Methods Lysozyme obtained from concha ostreae which were used to preparate marine lyso- zyme ...Aim To research therapeutical effect of marine lysozyme suppository on bacterial vaginitis caused by S. aureus and E. coll. Methods Lysozyme obtained from concha ostreae which were used to preparate marine lyso- zyme suppository. The identification and test of suppository was in line with the standards stated in Chinese pharma- coperia（2010 edition）. After determined its quality control, we studied its therapeutical effect on bacterial vaginitis which caused by S. aureus and E. coli, by vaginitis model in rats infection of S. aureus bacteria and E. coli. Results The preparation technology of marine lysozyme suppository was simple, convenient and clinically effective. The marine lysozyme suppository was delivered by dose 0.5, 0.25, 0. 125 g ~ kg-1, the cure rates of S. aureus infec- tion were 80% , 50% and 30% , respectively, the cure rates of E. coli infection were 90% , 60% and 30% re- spectively, the cure rates of mixed infection were 92.9% , 82. 1% and 92.9% respectively. Marine lysozyme sup- pository had an outstanding therapeutical effect on bacterial vaginitis which caused by S. aureus and E. coll. Con- clusion The preparative process of marine lysozyme suppository was practicable, and it had a good therapeutic effect on bacterial vaginitis caused by S. aureus and E. coll.展开更多
Goose parvovirus(GPV)can cause a highly contagious and fatal gosling plague(GP)disease in goslings and muscoy ducklings.Here,three goose-origin neutralizing single chain variable fragment(scFv)antibodies against GPV S...Goose parvovirus(GPV)can cause a highly contagious and fatal gosling plague(GP)disease in goslings and muscoy ducklings.Here,three goose-origin neutralizing single chain variable fragment(scFv)antibodies against GPV SYG-61 were isolated.The genes of scFv antibodies were derived from goslings immunized with GPV SYG-61,and scFvs were subcloned into a pBSD vector for the construction of pBSD-scFv libraries.The pBSD-scFv libraries were screened following three rounds using VP2(protective antigen of GPV)as the bait by flow cytometry(FCM).After screening,the 15 clones with high mean fluorescence intensity(MFI)were isolated and sequenced.These 15 scFvs were expressed by pET-28a(+)in E.coli.The specificity and affinity of the 15 purified scFvs were successfully confirmed by ELISA.In the preliminary neutralization experiment on primary goose embryo fibroblast(GEF)in vitro,three of the 15 purified scFvs(named scFv-10,scFv-11 and scFv-50)showed significant neutralizing capacities.The study generated the first goose-origin neutralizing scFv against GPV and laid the foundation for the appearance of full-length goose-origin neutralizing monoclonal antibody against GPV.展开更多
Objective:Patients with cerebrospinal fluid(CSF)pleocytosis are routinely admitted to the hospital and treated with parenteral antibiotics,although few have bacterial meningitis(BM).The aim of this study was to evalua...Objective:Patients with cerebrospinal fluid(CSF)pleocytosis are routinely admitted to the hospital and treated with parenteral antibiotics,although few have bacterial meningitis(BM).The aim of this study was to evaluate predictors to differentiate BM from aseptic meningitis(ASM).Methods:The study was conducted in Razi hospital,a training center affiliated to Ahvaz Joundishapoor University of Medical Sciences in Iran.and all patients were 18 years old or above and were treated in the hospital between 2003 and 2007.Data of those who had meningitis,tested as CSF pleocytosis but had not received antibiotic treatment before lumbar puncture were retrospectively analyzed.Results:Among 312 patients with CSF pleocytosis,two hundred fifteen(68.9%)had BM and ninety seven(31.1%)had ASM.The mean age for patients with BM was(34.7±17.7)years(P=0.22,NS).Sixty percent of the BM cases and 61.2% of the ASM cases occurred in men(P=0.70,NS).We identified the following predictors of BM:CSF-WBC count>100 per micro liter,CSF-glucose level<40 mg/dL,CSF-protein level>80 mg/dL.Sensitivity,specificity,PPV,NPV of these predictors,and LR for BM are 86.5%,52.6%,80.2%,63.7% and 104.1 for CSF-WBC count and 72.1%,83.5%,90.6%,57.4% and 164.2% for CSF glucose,and 49.7%,91.8%,93.4%,45.2% and 104.5% for CSF protein.Conclusion:The CSF WBC count should not be used alone to rule out bacterial meningitis.When it is combined with other factors such as CSF glucose and protein improved decision making in patients with suspected BM may occur.展开更多
OBJECTIVE To establish a small compound library via a versatile synthetic route for the investigation of natural-inspiring compounds containing N-hydroxypyridones motif as potential anti-plasmodial,anti-bacterial and ...OBJECTIVE To establish a small compound library via a versatile synthetic route for the investigation of natural-inspiring compounds containing N-hydroxypyridones motif as potential anti-plasmodial,anti-bacterial and iron(Ⅱ)-chelating agents.METHODS An amidation/cyclization approach was adopted to synthesize a library of N-hydroxyquinolinones.The anti-plasmodial susceptibility of lab clone 3D7 P.falciparum was measured using aprotocol modified from the WHO microtest.The minimum bactericidal concentration(MBC)values were determined against Escherichia coli and Staphylococcus arueus.Nine compounds were selected to test their iron(Ⅱ)-chelating abilities.The iron(Ⅱ)-chelating ability was determined by measuring the absorbance of ferrozine-iron complex at 562 nm.RESULTS A new route for the facile synthesis of a library of N-hydroxyquinolinones based on one-pot palladium catalyzed C-N amidation/dehydrocyclizationsequence was implemented.Four compounds show anti-plasmodial activities with the range of 1.1-1.4μmol·L-1,50% chelation abilities of the nine selected compounds were shown to be 0.24-0.29mmol·L-1.CONCLUSION Alibrary of N-hydroxyquinolinones was synthesized via a novel synthetic route.The anti-plasmodial and anti-bacterial activities of these compounds were evaluated.Four compounds show potent anti-plasmodial activities Nine compounds were examined for their propensities to undergo iron chelation and these compounds were shown to be promising iron(Ⅱ)chelators as compared to EDTA.展开更多
Acetobacteraceae has garnered significant attention because of its unique properties and the broad applications of the bacterial cellulose it produces.However,unlike model strains,Acetobacteraceae have few synthetic b...Acetobacteraceae has garnered significant attention because of its unique properties and the broad applications of the bacterial cellulose it produces.However,unlike model strains,Acetobacteraceae have few synthetic biology applications because they are difficult to manipulate genetically and have insufficient genetic regulatory elements,among other factors.To address this limitation,this study characterized the fundamental properties and synthetic biology elements of three commonly used bacterial cellulose-producing strains.First,the basic characteristics of the three strains,including their cellulose film production ability,division time,antibiotic susceptibility,and plasmid features,were analyzed.Two inducible promoters(pTrc and pLux101)were subsequently characterized within the three strains.The inducibility of the pTrc promoter was relatively low across the three strains(induction ratio:1.98–6.39),whereas the pLux101 promoter demonstrated a significantly greater level of inducibility within the three strains(induction ratio:87.28–216.71).Finally,through gene knockout experiments,this study identified four genes essential for bacterial cellulose film production in the genome of the Gluconacetobacter hansenii ATCC 5358 strain.This study not only enriches the library of synthetic biology elements in nonmodel strains,but also lays the foundation for the synthetic biology applications of Acetobacteraceae.展开更多
Changes in the bacterial communities inhabiting Agaricus bisporus compost during Phase Ⅱ treatment were monitored using amplified rDNA restriction analysis(ARDRA).Sequence analysis data indicated that the bacterial c...Changes in the bacterial communities inhabiting Agaricus bisporus compost during Phase Ⅱ treatment were monitored using amplified rDNA restriction analysis(ARDRA).Sequence analysis data indicated that the bacterial communities associated with the compost samples were far richer in composition when determined by ARDRA compared with traditional methods based on bacterial isolation.Furthermore,the composition of the communities,especially in terms of the dominant bacteria during each of the four treatment stages(beginning of Phase Ⅱ,after pasteurization,5 days aeration,end of Phase Ⅱ,respectively),were very different.Restriction endonuclease digestion of mainly bacterial clones from four 16S rDNA libraries,C1,C3,C6 and C7,previously constructed on the basis of 16S rDNA fragments amplified from the four different stages of the Phase Ⅱ composting process,revealed the presence of unique microbial types.Thermophilic bacteria belonging to the Bacilli,and previously unreported strains of Trichococcus,Planococcus,Caryophanon,and subclass γ-Proteobacteria,were identified among the clones from the compost sampled during the aeration period(C6).Bacteria belonging to Thermus thermophilus and subclass α-Proteobacteria were detected in C1 and C7 composts sampled at the beginning and the end of Phase Ⅱ,respectively.Clones of some uncultured bacteria were also scored.展开更多
基金supported by the National Natural Science Foundation of China(6137415361473138)+2 种基金Natural Science Foundation of Jiangsu Province(BK20151130)Six Talent Peaks Project in Jiangsu Province(2015-DZXX-011)China Scholarship Council Fund(201606845005)
文摘The quantum bacterial foraging optimization(QBFO)algorithm has the characteristics of strong robustness and global searching ability. In the classical QBFO algorithm, the rotation angle updated by the rotation gate is discrete and constant,which cannot affect the situation of the solution space and limit the diversity of bacterial population. In this paper, an improved QBFO(IQBFO) algorithm is proposed, which can adaptively make the quantum rotation angle continuously updated and enhance the global search ability. In the initialization process, the modified probability of the optimal rotation angle is introduced to avoid the existence of invariant solutions. The modified operator of probability amplitude is adopted to further increase the population diversity.The tests based on benchmark functions verify the effectiveness of the proposed algorithm. Moreover, compared with the integerorder PID controller, the fractional-order proportion integration differentiation(PID) controller increases the complexity of the system with better flexibility and robustness. Thus the fractional-order PID controller is applied to the servo system. The tuning results of PID parameters of the fractional-order servo system show that the proposed algorithm has a good performance in tuning the PID parameters of the fractional-order servo system.
基金Project(61173032)supported by the National Natural Science Foundation of ChinaProject(20090406)supported by the Tianjin Scientific and Technological Development Fund of Higher Education of China
文摘The utilization of biomimicry of bacterial foraging strategy was considered to develop an adaptive control strategy for mobile robot, and a bacterial foraging approach was proposed for robot path planning. In the proposed model, robot that mimics the behavior of bacteria is able to determine an optimal collision-free path between a start and a target point in the environment surrounded by obstacles. In the simulation, two test scenarios of static environment with different number obstacles were adopted to evaluate the performance of the proposed method. Simulation results show that the robot which reflects the bacterial foraging behavior can adapt to complex environments in the planned trajectories with both satisfactory accuracy and stability.
基金Heilongjiang Dairy Project Italian Grant Project
文摘The trail was designed to study on technique aspects of ensiling rice straw （RS） appended amounts of lactobacillus. There were two groups according to silage ways, baled silage （BS） and chopped silage （CS）, in which lactobacillus was added at levels of 10, 15 and 20 mg·kg^-1, respectively and the mixtures were placed into a packed polyethylene bags and stored at room temperature for 45 days. The results showed that lactobacillus had remarkable effect on fermentation characteristics of RS. The quality of the silage was improved with the lactobacillus addition. In the experiment the optimal quality of rice straw silage （RSS） can be obtained when lactobacillus was added with 15 or 20 mg·kg^-1 level. The effect of different silage methods was very remarkable to the silage quality of same material. The quality of CS was better than that of long silage, at the same time, BS was feasible on condition of eligible level of lactic acid bacteria.
基金Project(31300343)supported by the National Natural Science Foundation of ChinaProject(PCRRF19009)supported by Open Science Research Fund of State Key Laboratory of Pollution Control and Resource Reuse(Tongji University),ChinaProject supported by Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment,China。
文摘Understanding the impacts of co-invasion of multiple invaders on soil bacterial communities is significant in understanding the mechanisms driving successful invasion.This study aimed to determine the response of soil bacterial communities to co-invasion of two invaders daisy fleabane(Erigeron annuus)and Canada goldenrod(Solidago canadensis).Daisy fleabane and/or Canada goldenrod invasion significantly enhanced the operational taxonomic unit richness,Shannon index,and Chao1 index of soil bacterial communities.Canada goldenrod under light degree of invasion and co-invasion of daisy fleabane and Canada goldenrod regardless of invasion degree signally improved the ACE index of soil bacterial communities.Thus,the two invaders can enhance soil bacterial diversity and richness to facilitating subsequent invasion due to the fact that higher soil bacterial diversity and richness can enhance the levels of soil function and nutrients acquisition of plant species.ACE index of soil bacterial communities subjected to co-invasion of daisy fleabane and Canada goldenrod regardless of invasion degree was greater than that under the independent invasion of either daisy fleabane or Canada goldenrod.Hence,co-invasion of the two invaders can impose synergistic impacts on soil bacterial richness,which may build a preferable soil micro-environment via the intensified soil bacterial communities,which is contributive to their following invasion.
基金Project(50621063)supported by the Science Fund for Creative Research Groups of ChinaProject(2004CB619201)supported by the Major State Basic Research Development Program of China
文摘To reveal the impact of mining on bacterial ecology around mining area,bacterial community and geochemical characteristics about Dabaoshan Mine(Guangdong Province,China)were studied.By amplified ribosomal DNA restriction analysis and phylogenetic analysis,it is found that mining pollution greatly impacts the bacterial ecology and makes the habitat type of polluted environments close to acid mine drainage(AMD)ecology.The polluted environment is acidified so greatly that neutrophil and alkaliphilic microbes are massively dead and decomposed.It provided organic matters that can make Acidiphilium sp.rapidly grow and become the most bacterial species in this niche.Furthermore,Acidithiobacillus ferrooxidans and Leptospirillum sp.are also present in this niche.The amount of Leptospirillum sp.is far more than that of Acidithiobacillus ferrooxidans,which indicates that the concentration of toxic ions is very high.The conclusions of biogeochemical analysis and microbiological monitor are identical. Moreover,because the growth of Acidithiobacillus ferrooxidans and Leptospirillum sp.depends on ferrous iron or inorganic redox sulfur compounds which can be supplied by continual AMD,their presence indicates that AMD still flows into the site.And the area is closer to the outfalls of AMD,their biomasses would be more.So the distinction of their biomasses among different areas can help us to find the effluent route of AMD.
基金Project(2007AA060902) supported by the National High Technology Research and Development Program of ChinaProject(2010CB630905) supported by the National Basic Research Program of China
文摘The bacterial pre-oxidation process of arsenic-containing gold concentrates and the bacterial activity under different chloride ion concentrations were studied by using a mixture of thermophilic strains TCJ domesticated in production.The experimental result shows that with different samples and leaching systems,the adaptability and Cl- tolerance of bacteria are different,and that appropriate chloride ion concentration is conductive to bacterial oxidation,while higher chloride ion concentration will inhibit the bacterial activity and affect the pre-oxidation performance.Under the present production conditions,TCJ can adapt to the changes of water quality in the source of water and its critical chloride ion tolerance value is 2.7 g/L.
文摘Aim To research therapeutical effect of marine lysozyme suppository on bacterial vaginitis caused by S. aureus and E. coll. Methods Lysozyme obtained from concha ostreae which were used to preparate marine lyso- zyme suppository. The identification and test of suppository was in line with the standards stated in Chinese pharma- coperia（2010 edition）. After determined its quality control, we studied its therapeutical effect on bacterial vaginitis which caused by S. aureus and E. coli, by vaginitis model in rats infection of S. aureus bacteria and E. coli. Results The preparation technology of marine lysozyme suppository was simple, convenient and clinically effective. The marine lysozyme suppository was delivered by dose 0.5, 0.25, 0. 125 g ~ kg-1, the cure rates of S. aureus infec- tion were 80% , 50% and 30% , respectively, the cure rates of E. coli infection were 90% , 60% and 30% re- spectively, the cure rates of mixed infection were 92.9% , 82. 1% and 92.9% respectively. Marine lysozyme sup- pository had an outstanding therapeutical effect on bacterial vaginitis which caused by S. aureus and E. coll. Con- clusion The preparative process of marine lysozyme suppository was practicable, and it had a good therapeutic effect on bacterial vaginitis caused by S. aureus and E. coll.
基金Supported by the National Key R&D Program of China(2017YFD0501102,20I7YFD050I103-03 and 2017YFD0501004)Science and Technology Department of Heilongjiang Province(GX18B018)Education Department ofHeilongjiang Province(TSTAU-R2018017)。
文摘Goose parvovirus(GPV)can cause a highly contagious and fatal gosling plague(GP)disease in goslings and muscoy ducklings.Here,three goose-origin neutralizing single chain variable fragment(scFv)antibodies against GPV SYG-61 were isolated.The genes of scFv antibodies were derived from goslings immunized with GPV SYG-61,and scFvs were subcloned into a pBSD vector for the construction of pBSD-scFv libraries.The pBSD-scFv libraries were screened following three rounds using VP2(protective antigen of GPV)as the bait by flow cytometry(FCM).After screening,the 15 clones with high mean fluorescence intensity(MFI)were isolated and sequenced.These 15 scFvs were expressed by pET-28a(+)in E.coli.The specificity and affinity of the 15 purified scFvs were successfully confirmed by ELISA.In the preliminary neutralization experiment on primary goose embryo fibroblast(GEF)in vitro,three of the 15 purified scFvs(named scFv-10,scFv-11 and scFv-50)showed significant neutralizing capacities.The study generated the first goose-origin neutralizing scFv against GPV and laid the foundation for the appearance of full-length goose-origin neutralizing monoclonal antibody against GPV.
文摘Objective:Patients with cerebrospinal fluid(CSF)pleocytosis are routinely admitted to the hospital and treated with parenteral antibiotics,although few have bacterial meningitis(BM).The aim of this study was to evaluate predictors to differentiate BM from aseptic meningitis(ASM).Methods:The study was conducted in Razi hospital,a training center affiliated to Ahvaz Joundishapoor University of Medical Sciences in Iran.and all patients were 18 years old or above and were treated in the hospital between 2003 and 2007.Data of those who had meningitis,tested as CSF pleocytosis but had not received antibiotic treatment before lumbar puncture were retrospectively analyzed.Results:Among 312 patients with CSF pleocytosis,two hundred fifteen(68.9%)had BM and ninety seven(31.1%)had ASM.The mean age for patients with BM was(34.7±17.7)years(P=0.22,NS).Sixty percent of the BM cases and 61.2% of the ASM cases occurred in men(P=0.70,NS).We identified the following predictors of BM:CSF-WBC count>100 per micro liter,CSF-glucose level<40 mg/dL,CSF-protein level>80 mg/dL.Sensitivity,specificity,PPV,NPV of these predictors,and LR for BM are 86.5%,52.6%,80.2%,63.7% and 104.1 for CSF-WBC count and 72.1%,83.5%,90.6%,57.4% and 164.2% for CSF glucose,and 49.7%,91.8%,93.4%,45.2% and 104.5% for CSF protein.Conclusion:The CSF WBC count should not be used alone to rule out bacterial meningitis.When it is combined with other factors such as CSF glucose and protein improved decision making in patients with suspected BM may occur.
基金The project supported by the Agency for Science Technology and Research(A*STAR)(JCO-10/03/FG/06/02)
文摘OBJECTIVE To establish a small compound library via a versatile synthetic route for the investigation of natural-inspiring compounds containing N-hydroxypyridones motif as potential anti-plasmodial,anti-bacterial and iron(Ⅱ)-chelating agents.METHODS An amidation/cyclization approach was adopted to synthesize a library of N-hydroxyquinolinones.The anti-plasmodial susceptibility of lab clone 3D7 P.falciparum was measured using aprotocol modified from the WHO microtest.The minimum bactericidal concentration(MBC)values were determined against Escherichia coli and Staphylococcus arueus.Nine compounds were selected to test their iron(Ⅱ)-chelating abilities.The iron(Ⅱ)-chelating ability was determined by measuring the absorbance of ferrozine-iron complex at 562 nm.RESULTS A new route for the facile synthesis of a library of N-hydroxyquinolinones based on one-pot palladium catalyzed C-N amidation/dehydrocyclizationsequence was implemented.Four compounds show anti-plasmodial activities with the range of 1.1-1.4μmol·L-1,50% chelation abilities of the nine selected compounds were shown to be 0.24-0.29mmol·L-1.CONCLUSION Alibrary of N-hydroxyquinolinones was synthesized via a novel synthetic route.The anti-plasmodial and anti-bacterial activities of these compounds were evaluated.Four compounds show potent anti-plasmodial activities Nine compounds were examined for their propensities to undergo iron chelation and these compounds were shown to be promising iron(Ⅱ)chelators as compared to EDTA.
文摘Acetobacteraceae has garnered significant attention because of its unique properties and the broad applications of the bacterial cellulose it produces.However,unlike model strains,Acetobacteraceae have few synthetic biology applications because they are difficult to manipulate genetically and have insufficient genetic regulatory elements,among other factors.To address this limitation,this study characterized the fundamental properties and synthetic biology elements of three commonly used bacterial cellulose-producing strains.First,the basic characteristics of the three strains,including their cellulose film production ability,division time,antibiotic susceptibility,and plasmid features,were analyzed.Two inducible promoters(pTrc and pLux101)were subsequently characterized within the three strains.The inducibility of the pTrc promoter was relatively low across the three strains(induction ratio:1.98–6.39),whereas the pLux101 promoter demonstrated a significantly greater level of inducibility within the three strains(induction ratio:87.28–216.71).Finally,through gene knockout experiments,this study identified four genes essential for bacterial cellulose film production in the genome of the Gluconacetobacter hansenii ATCC 5358 strain.This study not only enriches the library of synthetic biology elements in nonmodel strains,but also lays the foundation for the synthetic biology applications of Acetobacteraceae.
基金Supported by project of China Agricultural Ministry(No.nyhyzx-07-008)
文摘Changes in the bacterial communities inhabiting Agaricus bisporus compost during Phase Ⅱ treatment were monitored using amplified rDNA restriction analysis(ARDRA).Sequence analysis data indicated that the bacterial communities associated with the compost samples were far richer in composition when determined by ARDRA compared with traditional methods based on bacterial isolation.Furthermore,the composition of the communities,especially in terms of the dominant bacteria during each of the four treatment stages(beginning of Phase Ⅱ,after pasteurization,5 days aeration,end of Phase Ⅱ,respectively),were very different.Restriction endonuclease digestion of mainly bacterial clones from four 16S rDNA libraries,C1,C3,C6 and C7,previously constructed on the basis of 16S rDNA fragments amplified from the four different stages of the Phase Ⅱ composting process,revealed the presence of unique microbial types.Thermophilic bacteria belonging to the Bacilli,and previously unreported strains of Trichococcus,Planococcus,Caryophanon,and subclass γ-Proteobacteria,were identified among the clones from the compost sampled during the aeration period(C6).Bacteria belonging to Thermus thermophilus and subclass α-Proteobacteria were detected in C1 and C7 composts sampled at the beginning and the end of Phase Ⅱ,respectively.Clones of some uncultured bacteria were also scored.
