Objective: To investigate the antibacterial activities of green vegetables(pennywort,mint, garlic, parsley and celery) against four common enteric bacteria [Salmonella enterica(ATCC 25957)(S. enterica), Shigella flexn...Objective: To investigate the antibacterial activities of green vegetables(pennywort,mint, garlic, parsley and celery) against four common enteric bacteria [Salmonella enterica(ATCC 25957)(S. enterica), Shigella flexneri(ATCC 12022)(S. flexneri),Escherichia coli(ATCC 43889)(E. coli) and Enterobacter cloacae(ATCC 13047)(E. cloacae)] as an alternative medicine for controlling food borne diarrhea disease and the synergistic effect of green vegetables against those bacteria.Methods: Five common vegetables(pennywort, mint, garlic, parsley and celery) were purchased and extracted. The antimicrobial activities of these extracts were tested against four common enteric bacteria(S. enterica, S. flexneri, E. coli and E. cloacae). Ten different concentrations of the extracts(from 640 to 1.25 mg/m L) were prepared and used for the study. The minimal inhibitory concentration(MIC) was determined by the broth dilution method. The antimicrobial activities were assessed by using both well diffusion and disc diffusion methods.Results: Garlic extract showed excellent inhibitory effects on all enteric bacteria. Other plants(parsley, celery, mint and pennywort) were not effective against enteric bacteria.The MIC of garlic against S. flexneri and E. cloacae was 40 mg/m L. The MIC of S. enterica and E. coli were 20 and 10 mg/m L, respectively. The performance of the well diffusion method was better than that of the disc diffusion method with clear and sharp inhibition zones of tested bacteria against plant extracts.Conclusions: Garlic had excellent antimicrobial effects against enteric bacteria and was recommended to be given to patients with gastroenteritis. The other vegetables(pennywort, mint, parsley and celery) showed no inhibitory effects on enteric bacteria but still can be used for its richness in vitamins and fibers. The performance of the well diffusion method was better than that of the disc diffusion method in detecting the antibacterial effects of green vegetables.展开更多
In order to compare the chemical compositions and physical properities of dusts on silicate bacteria S35, the chemical compositions of six kinds of mineral dusts have been analyzed and the changes of pH value, glucose...In order to compare the chemical compositions and physical properities of dusts on silicate bacteria S35, the chemical compositions of six kinds of mineral dusts have been analyzed and the changes of pH value, glucose （GLU）, electrolyte and Mn, Si, Fe before and after the dusts reacted with silicate bacteria S35 have been measured. The SEM analysis has been used to study the bacterial form and interface action status in the course of reaction between dusts and bacteria. The results show that these mineral dusts have different effects on experiment bacteria. Therefore, it is concluded that the effect of mineral dusts on silicate bacteria has correlation with the chemical compositions and physical properities of dusts.展开更多
The aim of this study was to isolate algicidal bacteria so as to control harmful cyanobacterium Microcystis aeruginosa （M. aeruginosa） blooms using biological methods. Nine bacterial strains were isolated to inhibit...The aim of this study was to isolate algicidal bacteria so as to control harmful cyanobacterium Microcystis aeruginosa （M. aeruginosa） blooms using biological methods. Nine bacterial strains were isolated to inhibit the growth ofM. aeruginosa, among which the Mail 1-5 bacterial strain exhibited remarkable algicidal activity against M. aeruginosa cells during the test. Based on the 16S rDNA analysis, the isolated Mail 1-5 was identified as Pedobacter sp. through morphology and homology research. The results of cocultivation of the cyanobacteria with MaI 11-5 algicidal isolates showed obvious algicidal activity against cyanobacterial cells. The algicidal effect of Mail 1-5 exceeded 50% after two days, exceeded 70% after four days, and reached 80% after seven days. The observation results with a scanning electron microscope showed that the cyanobacterial cells aggregated and produced mucous-like substances when cocultivated with the algicidal bacteria. The results indicated that the Mail 1-5 bacterial strain may possess a novel function for controlling harmful blooms and further studies will provide new insights into its role in water environment.展开更多
The effect of forests clear felling and associated burning on the population of soil nitrogen transforming bacteria and actinomycetes are reported at three pair sites of Chittagong University campus, Bangla- desh in m...The effect of forests clear felling and associated burning on the population of soil nitrogen transforming bacteria and actinomycetes are reported at three pair sites of Chittagong University campus, Bangla- desh in monsoon tropical climate. Clear felled area or burnt site and 15-21 year mixed plantation of native and exotic species, situated side by side on low hill having Typic Dystrochrepts soil was represented at each pair site. At all the three pair sites, clear felled area or burnt site showed very significantly （p~_0.001） lower population of actinomycetes, Rhizobium, Nitrosomonas, Nitrobacter and ammonifying as well as deni- trifying bacteria compared to their adjacent mixed plantation. From en- vironmental consideration, this finding has implication in managing natural ecosystem.展开更多
The Microcystis sample was selected from natural bloom water,then the algicidal effects of the bacterial strain fluid of the two algicidal bacteria,supernatant and bacterial liquid were studied. Moreover,the changes o...The Microcystis sample was selected from natural bloom water,then the algicidal effects of the bacterial strain fluid of the two algicidal bacteria,supernatant and bacterial liquid were studied. Moreover,the changes of microalgae colony and morphology in the process of algae-lysing were observed using neutral red staining and scanning electron microscope. It showed that AA06 bacteria had certain algicidal effect while AA10 bacteria had no effect. All the supernatants of the two bacterial strains had obvious algicidal effects,and the algicidal effects between the bacterial liquid and supernatant had no significant differences( P < 0. 05). The effects of algae-lysing mainly owed to the chemical substances secreted by algicidal bacteria. During the algae-lysing process,the algae colony did not disperse into individual cells. The segments of the dead cells still aggregated together.展开更多
OBJECTS: Hydrogen has been shown to possess antibacterial effects at high concentrations. In addition, chlorine has a strong bactericidal effect even at low concentrations. Electrolysis is a way to simultaneously gene...OBJECTS: Hydrogen has been shown to possess antibacterial effects at high concentrations. In addition, chlorine has a strong bactericidal effect even at low concentrations. Electrolysis is a way to simultaneously generate these two components. However, the concentration of hydrogen/free chlorine mixed water generated through electrolysis decreases quickly. It is predicted that the concentration of hydrogen/free chlorine mixed water will vary depending on the quality of water used. After investigating the optimum generation conditions, the effects of the most stable concentration of hydrogen/free chlorine mixed water on carious tooth fungus were evaluated in vitro. Thus, in this experiment, our goal was to evaluate the effects of hydrogen/free chlorine mixed water on oral bacteria. MATERIALS AND METHODS: Using a device that generates hydrogen/free chlorine through electrolysis, the differences in the concentrations of hydrogen and free chlorine based on electrolysis time were evaluated using tap water. Additionally, various concentration changes due to electrolysis time on the hydrogen/free chlorine mixed water were evaluated. Distilled tap water as a control group, hydrogen/free chlorine mixed water, and commercially available mouthwash were added for 1 minute to cultured Streptococcus mutans and then rinsed out with the culture medium. Bacterial growth (600 nm) and biofilm formation (590 nm) were measured at 3 and 6 hours after the addition of the medium. RESULTS: The concentration of hydrogen/chlorine mixed water produced by electrolysis varied depending on electrolysis time and the water used. The inhibitory effect of bacterial growth was enhanced depending on the chlorine concentration. Regarding the inhibitory effect on biofilm formation, only the mixed water of hydrogen/free chlorine concentration (500 ppb - 1.0 mg/L) had a suppressing effect after 6 hours. CONCLUSION: It was suggested that hydrogen/chlorine mixed water can be easily produced by electrolysis and has the effect of suppressing the growth of dental caries;therefore, it could be used as a cleaning agent in oral care products.展开更多
Antibiotic resistant bacteria pass between humans, between animals and between humans and animals in both directions, the use of antibiotics in poultry has contributed to multiple antibiotic resistant in pathogenic ba...Antibiotic resistant bacteria pass between humans, between animals and between humans and animals in both directions, the use of antibiotics in poultry has contributed to multiple antibiotic resistant in pathogenic bacteria and use of two antibiotics might prevent the emergence of resistance to either. In this study, synergistic effect of combined antibiotics against multidrug resistant human pathogenic bacterial isolates from poultry droppings in Akure, Nigeria was examined. Collection of samples, isolation and identification of bacteria were carried out using standard microbiological method, antibiotic sensitivity test was performed by disc diffusion method and zone of inhibition was used to interpret the sensitivity test as resistant, susceptible or intermediate while combined effects of two antibiotics were investigated by macrobroth dilution and checkerboard assay methods while the synergetic effects of combined antibiotics were calculated using Fractional Inhibitory Concentration (FIC) and percentage synergistic interaction was calculated. All the ten (10) species of bacterial isolates were multidrug resistant and are less resistant to ofloxacin. The highest percentage synergistic interactions observed were Ofloxacin + Amoxicillin (90%), Ciprofloxacin + Amoxicillin (90%), Tetracycline + Amoxicillin (70%), Tetracycline + Augmentin (80%), Cotrimoxazol + Amoxicillin (50%), Cotrimoxazol + Augmentin (70%), Chloramphenicol + Amoxicillin (70%) and Chloramphenicol + Augmentin (80%). Poultry droppings is a potential source of human pathogenic bacteria, high frequency of multiple antibiotic resistance bacteria observed in this study is of great treat to man as this may cause the treatment of infection caused by these bacteria to be difficult. Combination of beta-lactam antibiotic with fluoroqunolones, tetracycline, Chloramphenicol and Cotrimoxazole was synergetic and this will reduce dose related toxicity and prevent resistance to single antibiotic.展开更多
Objective:To investigate the in vitro antimicrobial potential of Thermopsis turcica Kit Tan,Vural&Kckdk against periodoutopathogenie bacteria,its antioxidant activity and cytotoxic effect on various cancer...Objective:To investigate the in vitro antimicrobial potential of Thermopsis turcica Kit Tan,Vural&Kckdk against periodoutopathogenie bacteria,its antioxidant activity and cytotoxic effect on various cancer cell lines.Methods:In vitro antimicrobial activities of elhanol.methanol,ethyl acetate(ElAc,n-hexane and water extracts of Thermopsis turcica herb against periodontopathogenic bacteria,Aggregatibacter actinnmycelemconilans ATCC 29523 and Porphyromonas gingivalis ATCC 33277 were tested by agar well diffusion,minimum inhibitory concentration(MIC)and minimal bactericidal concentration(MBC),Antioxidant properties of the extracts were evaluatod by 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity and p-carotene bleaching methods.Amounts of phenolic contents of the extracts were also analysed by using the Folin-Ciocalteu reagent.Additionally,cytotoxic activity of the extracts on androgcn-insensilivc prostate cancer,androgen—sensitive prostate cancer,chronic myelogenous leukemia and acute promyelocytic leukemia bunian cancer cell lines were determined by 3-4,5-dimelhylthiazol-2-yh-2,5-diphenyltclrazolium bromide assay.Human gingival fibroblast cells were used as a control.Results:Our data showed that ELAc extract had the highest antimicrobial effect on Aggregatibacter actinomycetemitans(MIC:1.562 mg/ml_MHC:3.124 mg/ml.)and Porph yromonas gingiralis(MIC:0.781 mg/mL,MBC:1.562 mg/mL).In antioxidant assays.ElAc extract exhibited also the highest radical scavenging activity[IC_(50)=(30.0±0.3)μg/ml.]and the highest inhibition[(74.35±0.30)%]|against lineloic acide oxidation.The amount of phenolic content of it was also the highest[(l62.5±l.2)μg/mg gallic acid].In cytotoxic assay,only etbanol[IC_(50)=(80.00±1.21)μg/ml.]and EtAc extract[IC_(50)=(70.0±0.9)μg/ml]were toxic on acute promyeloeytic leukemia cells at 20—100μg/mL.P<0.05>.However,no toxic effect was observed on human gingival fibroblast cells.Cunclusions:According to our findings,owing to its antioxidant and cytotoxic potential,EtAc exlrael might include anticancer agents for acute promyelocytic leukemia.展开更多
Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated effective in vitro antibacterial activity against all oral bacteria tested in this experiment. The antibacterial act...Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated effective in vitro antibacterial activity against all oral bacteria tested in this experiment. The antibacterial activities of CT against oral bacteria were assessed using the checkerboard and time-kill methods to evaluate the synergistic effects of treatment with ampicillin or gentamicin. The CT was determined against oral pathogenic bacteria with MIC and MBC values ranging from 0.5 to 16 and 1 to 64 μg/mL;for am- picillin from 0.0313 to 16 and 0.125 to 32 μg/mL;for gentamicin from 2 to 256 and 4 to 512 μg/mL respectively. The range of MIC50 and MIC90 were 0.0625 - 8 μg/mL and 1 - 64 μg/mL, respectively. The combination effects of CT with antibiotics were synergistic (FIC index < 0.5) against tested oral bacteria except additive, Streptococcus sobrinus, S. criceti, and Actinobacillus actinomycetemcomitans (FIC index < 0.75 - 1.0). The MBCs were shown reducing ≥4 - 8-fold, indicating a synergistic effect as defined by a FBCI of ≤0.5. Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 3 - 6 h of treatment with the 1/2 MIC of CT, regardless of whether it was administered alone or with ampicillin or gentamicin. The results suggest that CT could be employed as a natural antibacterial agent against cariogenic and periodontopathogenic bac- teria.展开更多
[ Objective ] The paper was to study the growth-promoting and antagonistic action of endophytic bacteria strains Itb57 and Itb295 of tobacco to explore their functions in biological control. [ Method] The growth-promo...[ Objective ] The paper was to study the growth-promoting and antagonistic action of endophytic bacteria strains Itb57 and Itb295 of tobacco to explore their functions in biological control. [ Method] The growth-promoting effects of bacterial suspension ~ff endophytic bacteria Itb57 and Itb295 on tobacco seedling un- der different treatment modes were studied using potting method in greenhouse. The antagonistic action of bacterial suspension of endophytic bacteria Itb57 and Itb295 on Phytophthora nicotianae, Alternaria alternata and Botrytis cinerea were measured by duel culture method. [ Result] Bacterial suspensions of enduphytic bacteria Itb57 and Itb295 had certain growth-promoting effects on tobacco seedling, which could significantly increase the fresh weight and dry weight in aerial part; the growth-promoting effect of soaking ＋ spraying and irrigating treatment was the best. Itb57 strain had good antagonistic action against P. nicotianae. A. alterna- ta and B. cinerea, while Itb295 strain only had good antifungal effect against P. nicotianae. [ Conclusion] The results provided basis for the study and application of tobacco endophytic bacteria strains Itb57 and Itb295 in biocontrol of tobacco diseases.展开更多
The degradation potential of a diesel-degrading bacteria(HDMP1) isolated from the oil-contaminated marine environment was explored systematically by analyzing the environmental conditions and synergistic action with o...The degradation potential of a diesel-degrading bacteria(HDMP1) isolated from the oil-contaminated marine environment was explored systematically by analyzing the environmental conditions and synergistic action with other dieseldegrading bacteria. The result indicated that HDMP1 was confirmed as a strain of Halomonas by the method of strain identification. And, HDMP1 showed good diesel degradation performance with a diesel degradation rate of up to 79.59%after 7 days. By analyzing the effect of environmental conditions on HDMP1, the best carbon and nitrogen sources were found to be lactose and peptone, respectively, at a pH value of 7.5 and a salinity of 4 g/(100 mL). Additionally, the synergistic effect of HDMP1 combined with other diesel-degrading bacteria was analyzed by orthogonal experimental design. The inocula of HDMP1, HDMP2, HDMP3 and HDMB3 were optimized, with the best results equating to 0.4%, 0.1%, 0.4% and0.9% in 100 mL of MSM, respectively, while the degradation rate of diesel was identified to be 73.5% within 5 days in the presence of optimum inocula.展开更多
In general, copper nanoclusters (CuNCs) possess very low or even virtually no bactericidal effect. Herein,we report a novel CuNCs possessing significantly high antibacterial activity, that is tannic acid (TA)capped Cu...In general, copper nanoclusters (CuNCs) possess very low or even virtually no bactericidal effect. Herein,we report a novel CuNCs possessing significantly high antibacterial activity, that is tannic acid (TA)capped CuNCs (TA-CuNCs). TA-CuNCs exhibit strong absorption and excitation-dependent fluorescence within pH 2-12, resulting from the functional groups of TA-CuNCs due to two prototropic equilibria,phenolphenolate and carboxyliccarboxylate. There exists synergistic effect of TA and copper nanoclusters which endows TA-CuNCs remarkable antibacterial capability as a microbicide, as characterized by the effective inhibition on the growth of gram-positive bacteria by damaging the cell membrane. By incubating 1 x 10~7 CFU/mL of gram-positive bacteria Staphylococcus aureus and Bacillus subtilis with 30 μg/mL of TA-CuNCs for 10 min, the bacteria are completely inhibited, while under same conditions the viabilities of gram-negative bacteria Escherichia coli 0157:H7 and Pseudomonas aeruginosa remain 85.0%, 72.0%, respectively. In addition, TA-CuNCs exhibit low cytotoxicity and favorable biocompatibility demonstrated by standard methyl thiazolyl tetrazolium (MTT) assay with HepG2 and 293 Tcells, giving rise to cell viability of 94.2% for HepG2 and 96.7% for 293 T by incubating 10~6 cell/mL with 200 μg/mL of TA-CuNCs for 24 h. These results make TA-CuNCs a potential alternative as bactericide for infection treatment caused by gram-positive bacteria.展开更多
There is no information on Nepalese sweet potato endophytes. We isolated 243 endophytic bacteria belonging to 34 genera in six classes from 12 locations of Nepal. Among them, the predominant classes were Bacilli and G...There is no information on Nepalese sweet potato endophytes. We isolated 243 endophytic bacteria belonging to 34 genera in six classes from 12 locations of Nepal. Among them, the predominant classes were Bacilli and Gammaproteobacteria. The principal component analysis revealed that the composition of bacterial classes was unrelated to the environmental parameters of the sampling sites. Regarding their plant growth promoting potentials, 57% of the strains demonstrated indole-3-acetic acid (IAA) producing ability while 5% strains had nitrogen fixing gene (nifH) and acetylene reduction assay (ARA) activity. The representative strains in all six classes showed antagonistic effect against bacterial pathogens while only Bacillus strain showed the effect against fungal pathogen. For endophytic traits, cellulase activity was observed in 5 classes, while pectinase activity was only in Proteobacteria. Fresh weight and vine length of sweet potato increased by inoculating mixed cultures of the isolates from each location.展开更多
基金Supported by Universiti Teknologi MARA(Ui TM)[Grant No.600-RMI/RAGS 5/3(63/204)]
文摘Objective: To investigate the antibacterial activities of green vegetables(pennywort,mint, garlic, parsley and celery) against four common enteric bacteria [Salmonella enterica(ATCC 25957)(S. enterica), Shigella flexneri(ATCC 12022)(S. flexneri),Escherichia coli(ATCC 43889)(E. coli) and Enterobacter cloacae(ATCC 13047)(E. cloacae)] as an alternative medicine for controlling food borne diarrhea disease and the synergistic effect of green vegetables against those bacteria.Methods: Five common vegetables(pennywort, mint, garlic, parsley and celery) were purchased and extracted. The antimicrobial activities of these extracts were tested against four common enteric bacteria(S. enterica, S. flexneri, E. coli and E. cloacae). Ten different concentrations of the extracts(from 640 to 1.25 mg/m L) were prepared and used for the study. The minimal inhibitory concentration(MIC) was determined by the broth dilution method. The antimicrobial activities were assessed by using both well diffusion and disc diffusion methods.Results: Garlic extract showed excellent inhibitory effects on all enteric bacteria. Other plants(parsley, celery, mint and pennywort) were not effective against enteric bacteria.The MIC of garlic against S. flexneri and E. cloacae was 40 mg/m L. The MIC of S. enterica and E. coli were 20 and 10 mg/m L, respectively. The performance of the well diffusion method was better than that of the disc diffusion method with clear and sharp inhibition zones of tested bacteria against plant extracts.Conclusions: Garlic had excellent antimicrobial effects against enteric bacteria and was recommended to be given to patients with gastroenteritis. The other vegetables(pennywort, mint, parsley and celery) showed no inhibitory effects on enteric bacteria but still can be used for its richness in vitamins and fibers. The performance of the well diffusion method was better than that of the disc diffusion method in detecting the antibacterial effects of green vegetables.
基金the National Natural Science Foundation of China （Grant 40072020）；the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE, P.R.C., the foundation of Key Laboratory of Solid Waste Treatment and the Resource Recycle of the Ministry of Education（Southwest University of Science and Technology）and the Support Item of Preeminence Youth Fund,Sichuan.
文摘In order to compare the chemical compositions and physical properities of dusts on silicate bacteria S35, the chemical compositions of six kinds of mineral dusts have been analyzed and the changes of pH value, glucose （GLU）, electrolyte and Mn, Si, Fe before and after the dusts reacted with silicate bacteria S35 have been measured. The SEM analysis has been used to study the bacterial form and interface action status in the course of reaction between dusts and bacteria. The results show that these mineral dusts have different effects on experiment bacteria. Therefore, it is concluded that the effect of mineral dusts on silicate bacteria has correlation with the chemical compositions and physical properities of dusts.
基金supported by the Basic Research Program of Jiangsu Province(Grant No.BK2012828)the grant of Greater Nagoya Project in Environmental Sciencethe Open Laboratory Project of Nanjing University of Technology(Grant No.2012-2013-138)
文摘The aim of this study was to isolate algicidal bacteria so as to control harmful cyanobacterium Microcystis aeruginosa （M. aeruginosa） blooms using biological methods. Nine bacterial strains were isolated to inhibit the growth ofM. aeruginosa, among which the Mail 1-5 bacterial strain exhibited remarkable algicidal activity against M. aeruginosa cells during the test. Based on the 16S rDNA analysis, the isolated Mail 1-5 was identified as Pedobacter sp. through morphology and homology research. The results of cocultivation of the cyanobacteria with MaI 11-5 algicidal isolates showed obvious algicidal activity against cyanobacterial cells. The algicidal effect of Mail 1-5 exceeded 50% after two days, exceeded 70% after four days, and reached 80% after seven days. The observation results with a scanning electron microscope showed that the cyanobacterial cells aggregated and produced mucous-like substances when cocultivated with the algicidal bacteria. The results indicated that the Mail 1-5 bacterial strain may possess a novel function for controlling harmful blooms and further studies will provide new insights into its role in water environment.
文摘The effect of forests clear felling and associated burning on the population of soil nitrogen transforming bacteria and actinomycetes are reported at three pair sites of Chittagong University campus, Bangla- desh in monsoon tropical climate. Clear felled area or burnt site and 15-21 year mixed plantation of native and exotic species, situated side by side on low hill having Typic Dystrochrepts soil was represented at each pair site. At all the three pair sites, clear felled area or burnt site showed very significantly （p~_0.001） lower population of actinomycetes, Rhizobium, Nitrosomonas, Nitrobacter and ammonifying as well as deni- trifying bacteria compared to their adjacent mixed plantation. From en- vironmental consideration, this finding has implication in managing natural ecosystem.
基金Supported by the Fund from Shenzhen Techand Econology&Environment Co.,Ltd.(THRD004)
文摘The Microcystis sample was selected from natural bloom water,then the algicidal effects of the bacterial strain fluid of the two algicidal bacteria,supernatant and bacterial liquid were studied. Moreover,the changes of microalgae colony and morphology in the process of algae-lysing were observed using neutral red staining and scanning electron microscope. It showed that AA06 bacteria had certain algicidal effect while AA10 bacteria had no effect. All the supernatants of the two bacterial strains had obvious algicidal effects,and the algicidal effects between the bacterial liquid and supernatant had no significant differences( P < 0. 05). The effects of algae-lysing mainly owed to the chemical substances secreted by algicidal bacteria. During the algae-lysing process,the algae colony did not disperse into individual cells. The segments of the dead cells still aggregated together.
文摘OBJECTS: Hydrogen has been shown to possess antibacterial effects at high concentrations. In addition, chlorine has a strong bactericidal effect even at low concentrations. Electrolysis is a way to simultaneously generate these two components. However, the concentration of hydrogen/free chlorine mixed water generated through electrolysis decreases quickly. It is predicted that the concentration of hydrogen/free chlorine mixed water will vary depending on the quality of water used. After investigating the optimum generation conditions, the effects of the most stable concentration of hydrogen/free chlorine mixed water on carious tooth fungus were evaluated in vitro. Thus, in this experiment, our goal was to evaluate the effects of hydrogen/free chlorine mixed water on oral bacteria. MATERIALS AND METHODS: Using a device that generates hydrogen/free chlorine through electrolysis, the differences in the concentrations of hydrogen and free chlorine based on electrolysis time were evaluated using tap water. Additionally, various concentration changes due to electrolysis time on the hydrogen/free chlorine mixed water were evaluated. Distilled tap water as a control group, hydrogen/free chlorine mixed water, and commercially available mouthwash were added for 1 minute to cultured Streptococcus mutans and then rinsed out with the culture medium. Bacterial growth (600 nm) and biofilm formation (590 nm) were measured at 3 and 6 hours after the addition of the medium. RESULTS: The concentration of hydrogen/chlorine mixed water produced by electrolysis varied depending on electrolysis time and the water used. The inhibitory effect of bacterial growth was enhanced depending on the chlorine concentration. Regarding the inhibitory effect on biofilm formation, only the mixed water of hydrogen/free chlorine concentration (500 ppb - 1.0 mg/L) had a suppressing effect after 6 hours. CONCLUSION: It was suggested that hydrogen/chlorine mixed water can be easily produced by electrolysis and has the effect of suppressing the growth of dental caries;therefore, it could be used as a cleaning agent in oral care products.
文摘Antibiotic resistant bacteria pass between humans, between animals and between humans and animals in both directions, the use of antibiotics in poultry has contributed to multiple antibiotic resistant in pathogenic bacteria and use of two antibiotics might prevent the emergence of resistance to either. In this study, synergistic effect of combined antibiotics against multidrug resistant human pathogenic bacterial isolates from poultry droppings in Akure, Nigeria was examined. Collection of samples, isolation and identification of bacteria were carried out using standard microbiological method, antibiotic sensitivity test was performed by disc diffusion method and zone of inhibition was used to interpret the sensitivity test as resistant, susceptible or intermediate while combined effects of two antibiotics were investigated by macrobroth dilution and checkerboard assay methods while the synergetic effects of combined antibiotics were calculated using Fractional Inhibitory Concentration (FIC) and percentage synergistic interaction was calculated. All the ten (10) species of bacterial isolates were multidrug resistant and are less resistant to ofloxacin. The highest percentage synergistic interactions observed were Ofloxacin + Amoxicillin (90%), Ciprofloxacin + Amoxicillin (90%), Tetracycline + Amoxicillin (70%), Tetracycline + Augmentin (80%), Cotrimoxazol + Amoxicillin (50%), Cotrimoxazol + Augmentin (70%), Chloramphenicol + Amoxicillin (70%) and Chloramphenicol + Augmentin (80%). Poultry droppings is a potential source of human pathogenic bacteria, high frequency of multiple antibiotic resistance bacteria observed in this study is of great treat to man as this may cause the treatment of infection caused by these bacteria to be difficult. Combination of beta-lactam antibiotic with fluoroqunolones, tetracycline, Chloramphenicol and Cotrimoxazole was synergetic and this will reduce dose related toxicity and prevent resistance to single antibiotic.
基金Supported by Minsitry of Devetopment of Tuckish Republie for Foundation of Moleculer Biology Research Center(Grant No.1998K121480)
文摘Objective:To investigate the in vitro antimicrobial potential of Thermopsis turcica Kit Tan,Vural&Kckdk against periodoutopathogenie bacteria,its antioxidant activity and cytotoxic effect on various cancer cell lines.Methods:In vitro antimicrobial activities of elhanol.methanol,ethyl acetate(ElAc,n-hexane and water extracts of Thermopsis turcica herb against periodontopathogenic bacteria,Aggregatibacter actinnmycelemconilans ATCC 29523 and Porphyromonas gingivalis ATCC 33277 were tested by agar well diffusion,minimum inhibitory concentration(MIC)and minimal bactericidal concentration(MBC),Antioxidant properties of the extracts were evaluatod by 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity and p-carotene bleaching methods.Amounts of phenolic contents of the extracts were also analysed by using the Folin-Ciocalteu reagent.Additionally,cytotoxic activity of the extracts on androgcn-insensilivc prostate cancer,androgen—sensitive prostate cancer,chronic myelogenous leukemia and acute promyelocytic leukemia bunian cancer cell lines were determined by 3-4,5-dimelhylthiazol-2-yh-2,5-diphenyltclrazolium bromide assay.Human gingival fibroblast cells were used as a control.Results:Our data showed that ELAc extract had the highest antimicrobial effect on Aggregatibacter actinomycetemitans(MIC:1.562 mg/ml_MHC:3.124 mg/ml.)and Porph yromonas gingiralis(MIC:0.781 mg/mL,MBC:1.562 mg/mL).In antioxidant assays.ElAc extract exhibited also the highest radical scavenging activity[IC_(50)=(30.0±0.3)μg/ml.]and the highest inhibition[(74.35±0.30)%]|against lineloic acide oxidation.The amount of phenolic content of it was also the highest[(l62.5±l.2)μg/mg gallic acid].In cytotoxic assay,only etbanol[IC_(50)=(80.00±1.21)μg/ml.]and EtAc extract[IC_(50)=(70.0±0.9)μg/ml]were toxic on acute promyeloeytic leukemia cells at 20—100μg/mL.P<0.05>.However,no toxic effect was observed on human gingival fibroblast cells.Cunclusions:According to our findings,owing to its antioxidant and cytotoxic potential,EtAc exlrael might include anticancer agents for acute promyelocytic leukemia.
文摘Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated effective in vitro antibacterial activity against all oral bacteria tested in this experiment. The antibacterial activities of CT against oral bacteria were assessed using the checkerboard and time-kill methods to evaluate the synergistic effects of treatment with ampicillin or gentamicin. The CT was determined against oral pathogenic bacteria with MIC and MBC values ranging from 0.5 to 16 and 1 to 64 μg/mL;for am- picillin from 0.0313 to 16 and 0.125 to 32 μg/mL;for gentamicin from 2 to 256 and 4 to 512 μg/mL respectively. The range of MIC50 and MIC90 were 0.0625 - 8 μg/mL and 1 - 64 μg/mL, respectively. The combination effects of CT with antibiotics were synergistic (FIC index < 0.5) against tested oral bacteria except additive, Streptococcus sobrinus, S. criceti, and Actinobacillus actinomycetemcomitans (FIC index < 0.75 - 1.0). The MBCs were shown reducing ≥4 - 8-fold, indicating a synergistic effect as defined by a FBCI of ≤0.5. Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 3 - 6 h of treatment with the 1/2 MIC of CT, regardless of whether it was administered alone or with ampicillin or gentamicin. The results suggest that CT could be employed as a natural antibacterial agent against cariogenic and periodontopathogenic bac- teria.
基金Supported by Natural Science Foundation of Chongqing City(CSTC,2009BB1294)~~
文摘[ Objective ] The paper was to study the growth-promoting and antagonistic action of endophytic bacteria strains Itb57 and Itb295 of tobacco to explore their functions in biological control. [ Method] The growth-promoting effects of bacterial suspension ~ff endophytic bacteria Itb57 and Itb295 on tobacco seedling un- der different treatment modes were studied using potting method in greenhouse. The antagonistic action of bacterial suspension of endophytic bacteria Itb57 and Itb295 on Phytophthora nicotianae, Alternaria alternata and Botrytis cinerea were measured by duel culture method. [ Result] Bacterial suspensions of enduphytic bacteria Itb57 and Itb295 had certain growth-promoting effects on tobacco seedling, which could significantly increase the fresh weight and dry weight in aerial part; the growth-promoting effect of soaking ＋ spraying and irrigating treatment was the best. Itb57 strain had good antagonistic action against P. nicotianae. A. alterna- ta and B. cinerea, while Itb295 strain only had good antifungal effect against P. nicotianae. [ Conclusion] The results provided basis for the study and application of tobacco endophytic bacteria strains Itb57 and Itb295 in biocontrol of tobacco diseases.
基金financially supported by the Scientific Research Fund Project of National Natural Science Foundation of China (Grant No. 51408347)the Open Research Fund Program of Shandong Provincial Key Laboratory of Oilfield Produced Water Treatment and Environmental Pollution Control (Sinopec Petroleum Engineering Corporation) (No.201801)+2 种基金the SDUST Young Teachers Teaching Talent Training Plan (BJRC20170502)the SDUST Graduate Tutor Guidance Ability Promotion Project (KDYC17023)the Sinopec Petroleum Engineering Corporation Key Scientific and Technological Project (JP15036)
文摘The degradation potential of a diesel-degrading bacteria(HDMP1) isolated from the oil-contaminated marine environment was explored systematically by analyzing the environmental conditions and synergistic action with other dieseldegrading bacteria. The result indicated that HDMP1 was confirmed as a strain of Halomonas by the method of strain identification. And, HDMP1 showed good diesel degradation performance with a diesel degradation rate of up to 79.59%after 7 days. By analyzing the effect of environmental conditions on HDMP1, the best carbon and nitrogen sources were found to be lactose and peptone, respectively, at a pH value of 7.5 and a salinity of 4 g/(100 mL). Additionally, the synergistic effect of HDMP1 combined with other diesel-degrading bacteria was analyzed by orthogonal experimental design. The inocula of HDMP1, HDMP2, HDMP3 and HDMB3 were optimized, with the best results equating to 0.4%, 0.1%, 0.4% and0.9% in 100 mL of MSM, respectively, while the degradation rate of diesel was identified to be 73.5% within 5 days in the presence of optimum inocula.
基金financially supported by the National Natural Science Foundation of China(Nos.21675019,21727811,21575020)Fundamental Research Funds for the Central Universities (Nos. N170505002,N170504017,N170507001)
文摘In general, copper nanoclusters (CuNCs) possess very low or even virtually no bactericidal effect. Herein,we report a novel CuNCs possessing significantly high antibacterial activity, that is tannic acid (TA)capped CuNCs (TA-CuNCs). TA-CuNCs exhibit strong absorption and excitation-dependent fluorescence within pH 2-12, resulting from the functional groups of TA-CuNCs due to two prototropic equilibria,phenolphenolate and carboxyliccarboxylate. There exists synergistic effect of TA and copper nanoclusters which endows TA-CuNCs remarkable antibacterial capability as a microbicide, as characterized by the effective inhibition on the growth of gram-positive bacteria by damaging the cell membrane. By incubating 1 x 10~7 CFU/mL of gram-positive bacteria Staphylococcus aureus and Bacillus subtilis with 30 μg/mL of TA-CuNCs for 10 min, the bacteria are completely inhibited, while under same conditions the viabilities of gram-negative bacteria Escherichia coli 0157:H7 and Pseudomonas aeruginosa remain 85.0%, 72.0%, respectively. In addition, TA-CuNCs exhibit low cytotoxicity and favorable biocompatibility demonstrated by standard methyl thiazolyl tetrazolium (MTT) assay with HepG2 and 293 Tcells, giving rise to cell viability of 94.2% for HepG2 and 96.7% for 293 T by incubating 10~6 cell/mL with 200 μg/mL of TA-CuNCs for 24 h. These results make TA-CuNCs a potential alternative as bactericide for infection treatment caused by gram-positive bacteria.
文摘There is no information on Nepalese sweet potato endophytes. We isolated 243 endophytic bacteria belonging to 34 genera in six classes from 12 locations of Nepal. Among them, the predominant classes were Bacilli and Gammaproteobacteria. The principal component analysis revealed that the composition of bacterial classes was unrelated to the environmental parameters of the sampling sites. Regarding their plant growth promoting potentials, 57% of the strains demonstrated indole-3-acetic acid (IAA) producing ability while 5% strains had nitrogen fixing gene (nifH) and acetylene reduction assay (ARA) activity. The representative strains in all six classes showed antagonistic effect against bacterial pathogens while only Bacillus strain showed the effect against fungal pathogen. For endophytic traits, cellulase activity was observed in 5 classes, while pectinase activity was only in Proteobacteria. Fresh weight and vine length of sweet potato increased by inoculating mixed cultures of the isolates from each location.
