The cultivation of Soledad pepper(Capsicum annuum L.)is essential in Oaxaca and Veracruz,but it faces issues with pests and diseases,which affect yield and cause economic losses.To mitigate these impacts,farmers have ...The cultivation of Soledad pepper(Capsicum annuum L.)is essential in Oaxaca and Veracruz,but it faces issues with pests and diseases,which affect yield and cause economic losses.To mitigate these impacts,farmers have started using biostimulants such as chitosan and plant growth promoting bacteria instead of agrochemicals due to their environmental and health benefits.This study evaluated the effect of Bacillus subtilis and chitosan,both individually and combined,on the growth,yield,and fruit quality of Soledad pepper under greenhouse conditions.Four treatments were applied at different stages of the crop cycle:Q(Chitosan),BS(Bacillus subtilis),Q+BS(Chitosan+Bacillus subtilis),and T(Control).The results showed that the combination of chitosan and Bacillus subtilis significantly improved plant growth,especially in height and stem diameter.The chitosan treatment produced the highest number of fruits and plant weight,while the combination of chitosan and Bacillus subtilis enhanced fruit quality,increasing characteristics such as size,weight,pericarp thickness,and physicochemical parameters,notably in brix degrees,citric acid percentage,and pH,outperforming the individual treatments and the control.展开更多
Benzo[a]pyrene(B[a]P)is a carcinogenic environmental pollutant widely present in the environment and can enter the human body through the food chain.It is therefore essential to treat and remediate the B[a]P-contamina...Benzo[a]pyrene(B[a]P)is a carcinogenic environmental pollutant widely present in the environment and can enter the human body through the food chain.It is therefore essential to treat and remediate the B[a]P-contaminated environment.Microbial remediation of B[a]Pcontaminated environments is considered to be one of the most effective strategies,and the addition of biostimulants is a feasible method to further improve the effectiveness of microbial remediation.In this study,we used Bacillus subtilis MSC4 to screen for the stimulation of sodium gluconate,which promoted B[a]P degradation.Based on biochemical and transcriptomic analyses,Sodium gluconate was found to significantly increase the biomass of MSC4 and the expression of most genes involved in B[a]P degradation.Activities of central carbon metabolism,fatty acidβ-oxidation and oxidative phosphorylation were all promoted.The significant increase in acid-induced oxalate decarboxylase expression indicates a decrease in intracellular pH,which promoted the synthesis of acetoin and lactate.Genes involved in the nitrogen cycle,especially nitrification and denitrification,were significantly up-regulated,contributing to B[a]P degradation.Genes involved in the synthesis of enzyme cofactors,including thiamine,molybdenum cofactors,NAD and heme,were up-regulated,which contributes to increasing enzyme activity in metabolic pathways.Up-regulation of genes in flagella assembly,chemotaxis,and lipopeptide synthesis is beneficial for the dissolution and uptake of B[a]P.Genes related to the sugar transport system were upregulated,which facilitates the transport and absorption of monosaccharides and oligosaccharides by MSC4.This study provides a theoretical basis for the further application of sodium gluconate in the treatment of PAH-contaminated sites.展开更多
The impact of Bacillus subtilis(B.subtilis)on the corrosion behavior(microbiologically influenced corrosion)of two aluminum alloys—7075 aluminum alloy(AA7075)and 2024 aluminum alloy(AA2024)—is investigated in a high...The impact of Bacillus subtilis(B.subtilis)on the corrosion behavior(microbiologically influenced corrosion)of two aluminum alloys—7075 aluminum alloy(AA7075)and 2024 aluminum alloy(AA2024)—is investigated in a high-salinity environment.The corrosion mechanism is explored by observing the bacterial growth process and the corresponding measurements.The assessment involves the analysis of surface morphology,corrosion mass loss,and electrochemical tests.Surface morphology reveals the development of B.subtilis and biofilm formation on the surface of the aluminum alloys.Both mass loss and electrochemical tests illustrate the corrosion inhibition effect of B.subtilis on aluminum alloys in a high-salt environment.AA7075 alloy was more affected by the biofilm and had a more pronounced corrosion inhibition effect.After 10 d of testing,in B.subtilis group,AA7075 and AA2024 bode values were elevated by 0.32×10^(4) and 0.24×10^(4)Ω,respectively.The open circuit potential of AA2024 decreased by−0.107 A/cm^(2) under the influence of bacteria,and the dynamic potentiodynamic polarization curve shifted significantly to the left.展开更多
Bacillus subtilis JZXJ-7 isolated from shrimp paste can significantly degrade histamine under salt stress but the mechanism is unclear.This study aims to evaluate the effect of 170 and 340 mmol/L Na Cl on B.subtilis J...Bacillus subtilis JZXJ-7 isolated from shrimp paste can significantly degrade histamine under salt stress but the mechanism is unclear.This study aims to evaluate the effect of 170 and 340 mmol/L Na Cl on B.subtilis JZXJ-7 growth,histamine degradation,antioxidant enzymes(catalase(CAT),superoxide dismutase(SOD)and glutathione S-transferase(GST))activities and Na^(+)/K^(+)-ATPase activity.Furthermore,comparative metabolomics was used to investigate histamine biodegradation mechanism by B.subtilis JZXJ-7 subjected to salt stress.Both 170 and 340 mmol/L Na Cl promoted B.subtilis JZXJ-7 growth in late stages of reproduction(32-48 h),increased h istamine degradation rate by 64.85%and 79.87%(P<0.05),Na^(+)/K^(+)-ATPase activity to 6.28(P<0.05)and 11.63 U/mg(P<0.01)respectively.N a Cl treatment significantly increased the activities of CAT,GST and SOD(P<0.05),a mino acids and its metabolites(33.39%),benzene and substituted derivatives(12.05%),heterocyclic compounds(10.62%),organic acids and derivatives(9.75%),aldehydes,ketones,esters(5.59%)and nucleotides and its metabolites(4.58%).Metabolite set enrichment analysis revealed Na Cl induced differential metabolic pathways of D-glutamine,D-glutamate,L-arginine,L-proline,histidine and glycerophospholipids,L-lysine degradation,and aminoacyl-t RNA biosynthesis.Exposure to 340 mmol/L Na Cl up-regulated carbohydrate,glutathione and glycerophospholipid metabolism.The new insights into the mechanism of salt stress to promote B.subtilis JZJX-7 growth,energy metabolic pathways and to degrade histamine provide the theoretical basis for application of B.subtilis JZXJ-7 in food fermentation industry.展开更多
6′-sialyllactose(6′-SL)is an important component of human milk oligosaccharides(HMOs)and has numerous infant health benefits.The construction of efficient and food-safe microbial cell factories to produce 6′-SL has...6′-sialyllactose(6′-SL)is an important component of human milk oligosaccharides(HMOs)and has numerous infant health benefits.The construction of efficient and food-safe microbial cell factories to produce 6′-SL has attracted increasing attention.In this study,a Bacillus subtilis strain was metabolically engineered for 6′-SL production.First,a de novo synthesis pathway for 6′-SL was constructed by heterologous expression of neuC,neuB,neuA,and pst6,enabling 6′-SL synthesis at a titer of 135.17 mg/L.Subsequently,bioinformatics-guided enzyme modification and promoter substitution strategies were used to fine-tune the pathway strength.Moreover,inhibition of competing pathways and copy number optimization of synthetic modules were used to increase the precursor concentration,raising 6′-SL titer to 621.8 mg/L.Furthermore,a strategy to overcome carbon catabolite repression(CCR)was developed for B.subtilis to improve lactose utilization and increase 6′-SL titers,reaching 3.55 g/L in shake flasks and 15.0 g/L in 3-L fermenters.This study established a foundation for efficient 6′-SL production.展开更多
Green-synthesized nanomaterials are anticipated to be extensively applied to inhibit sulfate-reducing bacteria(SRB)in oilfields.Using Bacillus subtilis(B.subtilis)suspension as the raw material and zinc acetate dihydr...Green-synthesized nanomaterials are anticipated to be extensively applied to inhibit sulfate-reducing bacteria(SRB)in oilfields.Using Bacillus subtilis(B.subtilis)suspension as the raw material and zinc acetate dihydrate(C4H6O4Zn·2H2O)along with silver nitrate(AgNO3)as precursors,Ag-ZnO nanoparticles(NPs)were synthesized using a simple and environment-friendly approach.The resulting Ag-ZnO NPs showed a rough surface morphology combined with high dispersibility,showing a particle size distribution of 33-35 nm.Protease and lipopeptides were identified as potential key agents driving the synthesis of Ag-ZnO NPs.At 40μg/mL,the Ag-ZnO nano-solution effectively inhibited SRB cell growth and reduced the corrosion rate of carbon steel materials induced by SRB.Notably,reactive oxygen species(ROS)and malondialdehyde(MDA)levels increased significantly in SRB cells treated with Ag-ZnO NPs,while cell viability declined,indicating that the nanoparticles caused irreversible damage to SRB biofilms.The inhibitory mechanisms of the NPs against SRB cells were proposed to involve physical electrostatic interactions,metal ion toxicity,cell membrane disruption,and cell lysis.展开更多
[Objective] The aim of this study was to breed new strains which have higher inhibitory effects on the pathogens of watermelon fusarium wilt.[Method] The endophytic Bacillus subtilis B47 strain was obtained from tomat...[Objective] The aim of this study was to breed new strains which have higher inhibitory effects on the pathogens of watermelon fusarium wilt.[Method] The endophytic Bacillus subtilis B47 strain was obtained from tomato stems by UV mutagenesis for two consecutive times,then genetic stability as well as physiological and biochemical properties of mutant strains were studied.[Result] The antibacterial activity of all the three mutant strains F303,F304 and F305 was higher than that of B74 strain.After subculture of 10 successive generations,the antibacterial activity of all the three mutant strains for the pathogens of watermelon fusarium wilt decreased,but the antibacterial activity of F305 strain decreased the least,indicating its best genetic stability among the tested strains.The antibacterial circle diameter of F305 strain was 5 mm larger than that of wild strain B47 under the same condition.The mutant strain F305 was in logarithmic growth phase within 36 h and in stationary phase within 36-96 h,while its optimum growth temperature was 35 ℃.F305 strain could grow in sodium salt with the concentration of 1%-10%,but it grew best at the concentration of 1%.Physiological and biochemical responses of F305 strain were in accordance with those of wild strain B47.[Conclusion] This study lays the foundation for the factorial production of antagonistic substance by B47 strain and new methods of preventing from the pathogens watermelon fusarium wilt.展开更多
[ Objective] The research aimed to get the optimized separation and purification conditions of the hirudin produced from Bacillus subtilis DB403 （pUBH5）. [Method] Through the systemic pretreatment, preliminary chrom...[ Objective] The research aimed to get the optimized separation and purification conditions of the hirudin produced from Bacillus subtilis DB403 （pUBH5）. [Method] Through the systemic pretreatment, preliminary chromatography and fine chromatography. [Result]The optimized separation and purification conditions were that： Supernatant was treated by trichloroacetic acid, then by ultrafiltration desalt and anion exchange chromatography. Strong anion Q F. F. was better than weak anion DEAE F.F. The proper balanced solution was Tris-HCI （ pH 8.0）. The proper conductivity was 6 ms/cm. The maximum applied sample was 240 ATU/ml to matrix of strong anion Q F. F. This optimized procedure was magnified in strong anion exchange HiPrep 16/10Q with the 90% recovery and 70.2% purity. The purification of gel filtration of Sephacryl S-100 to hirudin was not relative to flow rate within certain scope. The application size of sample was 10 ml. The purity checked by HPLC was 95.1%, and the recovery was 93%, and the band of SDS-PAGE was single. [ Conclusion] The research provided the reference of the further industrialization separation and purification of hiruin.展开更多
[Objective] This study was to investigate the effect of N＋ ion beam implantation on the survival rate and mutation rate of biocontrol strain Bacillus subtilis. [Method] The factors influencing B. subtilis ion beam im...[Objective] This study was to investigate the effect of N＋ ion beam implantation on the survival rate and mutation rate of biocontrol strain Bacillus subtilis. [Method] The factors influencing B. subtilis ion beam implantation, including culture time, dilution concentration, solvent, drying time of mycoderm were optimized. B. subtilis cells were implanted by using ion beam at dose of 2.0×10^14～4.0×10^14 ions/cm2 and the energy of 30 kev. Then the methods of culturing colonies confronting each other on plate and Oxford cup diffusion were used to screening strains. [Result] The optimal parameters were found as follows： culture in liquid for 20-24 h, dilution with sterile water to 106 cells/ml and drying time of 60 min for sample preparation; the optimal N＋ ion beam implantation dose of 2.0×10^14～4.0×10^14 ions/cm2 at the energy of 30 kev, the survival rate of 8.43%-26.71% and the mutation rate of 3.50%-5.43%. [Conclusion] This study provided reference for ion beam implantation mutation of B. subtilis.展开更多
[Objectives] This paper aims to explore the possibility to intercrop garlic with pomegranate tree to control pomegranate wilt.[Methods] Root exudates of garlic is cultivated in 1/5 concentration of MS solution and dis...[Objectives] This paper aims to explore the possibility to intercrop garlic with pomegranate tree to control pomegranate wilt.[Methods] Root exudates of garlic is cultivated in 1/5 concentration of MS solution and distilled water is examined in lab to test their effect to growth of mycelia of pomegranate wilt pathogen（Ceratocystis fimbriata）and multiplication of Bacillus subtilis.[Results] The result shows that garlic root exudates whatever cultivated in MS solution or distilled water could not inhibit or promote mycelia growth of C.fimbriata.However,garlic root exudates cultivated in both methods effectively promote multiplication of B.subtilis.[Conclusions] It is suggested that intercropping garlic with pomegranate tree by combining application B.subtilis could be a promising way to prevent pomegranate wilt spread in practice.展开更多
[ Objective] The paper was to obtain biocontrol strains with good control effects against ginseng soil-borne disease through screening. [ Method] Dilu- tion plate method and plate confrontation culture method were use...[ Objective] The paper was to obtain biocontrol strains with good control effects against ginseng soil-borne disease through screening. [ Method] Dilu- tion plate method and plate confrontation culture method were used to isolate and screen biocontrol bacteria from the rhizosphere soil of diseased ginseng. The strains were identified through morphology, physiological and biochemical characteristics and 16S rDNA. [ Result ] With Rhizoctonia solani, Fusarium oxysporum and Fu- sarium solani as the indicator strains, two biocontrol strains B59 and X1 with strong antagonistic effects were screened from the rhizosphere soil of diseased ginseng in Tieli farm of Heilongjiang Province, and they were identified to be Bacillus subtilis. The inhibition rates of two biocontrol strains against eight different fungi were all greater than 90%. The primary study indicated that B59 and X1 strains could secrete antifungal active substances. [ Conclusion] Two biocontrol Bacillus subti- lis strains 1359 and X1 all had strong antagonistic effect against ginseng soil-borne disease, which had certain potential for development and utilization.展开更多
[Objective] To screen out the biological compound bactericides for grape anthracnose, reduce and replace the use of chemical pesticide. [Methods] The de- termination on the indoor bacteriostatic activity of different ...[Objective] To screen out the biological compound bactericides for grape anthracnose, reduce and replace the use of chemical pesticide. [Methods] The de- termination on the indoor bacteriostatic activity of different proportions of Bacillus subtilis and pyraclostrobin to grape anthracnose was carried out, and mycelial growth rate method was adopted to determine the toxicity of Bacillus subtilis and pyraclostrobin as well as their 5 mixtures to grape anthracnose. [Results] The EC50 of Bacillus subtilis and pyraclostrobin as well as their mixture combinations of 1：1, 1：2, 1：3, 1：4 and 1：5 to grape anthracnose were respectively 1.969 8, 1.527 4, 1.373 2, 1.294 8 and 1.247 3 μg/ml; the synergistic coefficients （SR） of the 5 mix- ture combinations to grape anthracnose were 1.70, 1.25, 1.13, 1.12 and 1.12, re- spectively, in which the synergistic effect of 1：1 was the largest. The indoor biologi- cal activity of pyraclostrobin（EC50 was 1.054 0μg/ml） was higher than that of Bacil- lus subtilis（EC50 was 15.017 5 μg/ml）. 50 d after the agentia（before the harvesting）, the investigation results showed that 1 000-fold dilution, 1 500-fold dilution and 2 000- fold dilution as well as each single dosage of 20% pyraclostrobin .200×10^8 cfu/g Bacillus subtili wettable powder all had better control efficiency to grape anthracnose after fruit setting and before bagging, in which the treatments of high concentration and middle concentration were higher than the treatments of low concentration and two single dosages： the highest control efficiency of high concentration was 90.03%, which was higher than all other treatments; the control efficiency of middle concen- tration was 87.01%, which was higher than that of low concentration and each sin- gle dosage; the control efficiency of low concentration was 84.11%, which was high- er than 1 000-fold dilution of 1 000×10^8 cfu/g Bacillus subti/i wettable powder （the control efficiency was 64.60%） and 2 000-fold dilution of 250 g/L Bacillus subti/i wettable powder （the control efficiency was 81.07%）. In addition, each treatment al- so had better control efficiency to other cluster diseases, such as white rot, etc., and the control efficiency was almost the same as that of anthracnose. [Conclusion] It was suggested that the prevention concentration of 20% pyraclostrobin .200×10^8 cfu/g Bacillus subtili wettable powder to grape anthracnose after fruit setting and before bagging was 1 000-fold - 2 000-fold dilution.展开更多
Curing of Bacillus subtilis plasmid using sodium dodecyl sulfate (SDS)was studied in order to obtain a host strain. An overnight culture of Bacillus subtilis 24/pMX45 was used to inoculate fresh LB containing SDS (0-0...Curing of Bacillus subtilis plasmid using sodium dodecyl sulfate (SDS)was studied in order to obtain a host strain. An overnight culture of Bacillus subtilis 24/pMX45 was used to inoculate fresh LB containing SDS (0-0.008%). No growth of 24/pMX45 was observed when LB contained an SDS concentration of 0.006% or greater, and the sublethal concentration (w/v) of SDS was 0.005% with a killing rate of 99%. Samples were diluted and plated on LB agar, individual colonies were randomly picked to a selective agar medium by tooth to screen for loss of plasmid-encoded erythomycin resistance. CsCl-EtBr gradient centrifugation and plasmid DNA profile demonstrated that plasmid-cured derivative A7 has completely lost its plasmid. A7 had a shorter lag, and its cell concentration was consistently higher than that of the 24/pMX45. Elimination of the plasmid was first observed after 24/pMX45 had been treated with SDS for 8 h. The percent elimination then continued to increase until about 22 h, after which the fraction of cured cell in the population remained constant. Plasmid cured cell numbers were measured in a separate control culture of 24/pMX45 untreated by SDS. No spontaneous loss of pMX45 was observed after 24/pMX45 were incubated for 24 h and 48 h with shaking at 37 ℃.These results suggested that SDS can be used as curing agent to eliminate the plasmid of Bacillus subtilis.展开更多
文摘The cultivation of Soledad pepper(Capsicum annuum L.)is essential in Oaxaca and Veracruz,but it faces issues with pests and diseases,which affect yield and cause economic losses.To mitigate these impacts,farmers have started using biostimulants such as chitosan and plant growth promoting bacteria instead of agrochemicals due to their environmental and health benefits.This study evaluated the effect of Bacillus subtilis and chitosan,both individually and combined,on the growth,yield,and fruit quality of Soledad pepper under greenhouse conditions.Four treatments were applied at different stages of the crop cycle:Q(Chitosan),BS(Bacillus subtilis),Q+BS(Chitosan+Bacillus subtilis),and T(Control).The results showed that the combination of chitosan and Bacillus subtilis significantly improved plant growth,especially in height and stem diameter.The chitosan treatment produced the highest number of fruits and plant weight,while the combination of chitosan and Bacillus subtilis enhanced fruit quality,increasing characteristics such as size,weight,pericarp thickness,and physicochemical parameters,notably in brix degrees,citric acid percentage,and pH,outperforming the individual treatments and the control.
基金supported by the National Key R&D Program of China(No.2020YFC1808803).
文摘Benzo[a]pyrene(B[a]P)is a carcinogenic environmental pollutant widely present in the environment and can enter the human body through the food chain.It is therefore essential to treat and remediate the B[a]P-contaminated environment.Microbial remediation of B[a]Pcontaminated environments is considered to be one of the most effective strategies,and the addition of biostimulants is a feasible method to further improve the effectiveness of microbial remediation.In this study,we used Bacillus subtilis MSC4 to screen for the stimulation of sodium gluconate,which promoted B[a]P degradation.Based on biochemical and transcriptomic analyses,Sodium gluconate was found to significantly increase the biomass of MSC4 and the expression of most genes involved in B[a]P degradation.Activities of central carbon metabolism,fatty acidβ-oxidation and oxidative phosphorylation were all promoted.The significant increase in acid-induced oxalate decarboxylase expression indicates a decrease in intracellular pH,which promoted the synthesis of acetoin and lactate.Genes involved in the nitrogen cycle,especially nitrification and denitrification,were significantly up-regulated,contributing to B[a]P degradation.Genes involved in the synthesis of enzyme cofactors,including thiamine,molybdenum cofactors,NAD and heme,were up-regulated,which contributes to increasing enzyme activity in metabolic pathways.Up-regulation of genes in flagella assembly,chemotaxis,and lipopeptide synthesis is beneficial for the dissolution and uptake of B[a]P.Genes related to the sugar transport system were upregulated,which facilitates the transport and absorption of monosaccharides and oligosaccharides by MSC4.This study provides a theoretical basis for the further application of sodium gluconate in the treatment of PAH-contaminated sites.
基金supported by the National Natural Science Foundation of China(No.52073311)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515012281)+1 种基金Guangdong-Hong Kong-Macao Joint Innovation Field Research Foundation(No.2023A0505010011)Zhuhai Industry University Research Cooperation Project(No.ZH22017001210148PWC).
文摘The impact of Bacillus subtilis(B.subtilis)on the corrosion behavior(microbiologically influenced corrosion)of two aluminum alloys—7075 aluminum alloy(AA7075)and 2024 aluminum alloy(AA2024)—is investigated in a high-salinity environment.The corrosion mechanism is explored by observing the bacterial growth process and the corresponding measurements.The assessment involves the analysis of surface morphology,corrosion mass loss,and electrochemical tests.Surface morphology reveals the development of B.subtilis and biofilm formation on the surface of the aluminum alloys.Both mass loss and electrochemical tests illustrate the corrosion inhibition effect of B.subtilis on aluminum alloys in a high-salt environment.AA7075 alloy was more affected by the biofilm and had a more pronounced corrosion inhibition effect.After 10 d of testing,in B.subtilis group,AA7075 and AA2024 bode values were elevated by 0.32×10^(4) and 0.24×10^(4)Ω,respectively.The open circuit potential of AA2024 decreased by−0.107 A/cm^(2) under the influence of bacteria,and the dynamic potentiodynamic polarization curve shifted significantly to the left.
基金supported by the National Key R&D Program of China(2019YFD0901702)National Natural Science Foundation of China(32201929,32202134)+3 种基金2025 Guangdong Basic and Applied Basic Research Foundation of Natural Science Foundation Project(2025A1515011748)High-level Talent Project of Lingnan Normal University(ZL2415)China Postdoctoral Science Foundation(2022M712625)2021 and 2022 Chongqing Postdoctoral Special Funding Project。
文摘Bacillus subtilis JZXJ-7 isolated from shrimp paste can significantly degrade histamine under salt stress but the mechanism is unclear.This study aims to evaluate the effect of 170 and 340 mmol/L Na Cl on B.subtilis JZXJ-7 growth,histamine degradation,antioxidant enzymes(catalase(CAT),superoxide dismutase(SOD)and glutathione S-transferase(GST))activities and Na^(+)/K^(+)-ATPase activity.Furthermore,comparative metabolomics was used to investigate histamine biodegradation mechanism by B.subtilis JZXJ-7 subjected to salt stress.Both 170 and 340 mmol/L Na Cl promoted B.subtilis JZXJ-7 growth in late stages of reproduction(32-48 h),increased h istamine degradation rate by 64.85%and 79.87%(P<0.05),Na^(+)/K^(+)-ATPase activity to 6.28(P<0.05)and 11.63 U/mg(P<0.01)respectively.N a Cl treatment significantly increased the activities of CAT,GST and SOD(P<0.05),a mino acids and its metabolites(33.39%),benzene and substituted derivatives(12.05%),heterocyclic compounds(10.62%),organic acids and derivatives(9.75%),aldehydes,ketones,esters(5.59%)and nucleotides and its metabolites(4.58%).Metabolite set enrichment analysis revealed Na Cl induced differential metabolic pathways of D-glutamine,D-glutamate,L-arginine,L-proline,histidine and glycerophospholipids,L-lysine degradation,and aminoacyl-t RNA biosynthesis.Exposure to 340 mmol/L Na Cl up-regulated carbohydrate,glutathione and glycerophospholipid metabolism.The new insights into the mechanism of salt stress to promote B.subtilis JZJX-7 growth,energy metabolic pathways and to degrade histamine provide the theoretical basis for application of B.subtilis JZXJ-7 in food fermentation industry.
基金financially supported by the National Key Research and Development Program of China(2022YFC3401303)the National Natural Science Foundation of China(32070085,32200050,31871784,and 32021005)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20221079)the Fundamental Research Funds for the Central Universities(JUSRP52019A,JUSRP121010 and JUSRP221013).
文摘6′-sialyllactose(6′-SL)is an important component of human milk oligosaccharides(HMOs)and has numerous infant health benefits.The construction of efficient and food-safe microbial cell factories to produce 6′-SL has attracted increasing attention.In this study,a Bacillus subtilis strain was metabolically engineered for 6′-SL production.First,a de novo synthesis pathway for 6′-SL was constructed by heterologous expression of neuC,neuB,neuA,and pst6,enabling 6′-SL synthesis at a titer of 135.17 mg/L.Subsequently,bioinformatics-guided enzyme modification and promoter substitution strategies were used to fine-tune the pathway strength.Moreover,inhibition of competing pathways and copy number optimization of synthetic modules were used to increase the precursor concentration,raising 6′-SL titer to 621.8 mg/L.Furthermore,a strategy to overcome carbon catabolite repression(CCR)was developed for B.subtilis to improve lactose utilization and increase 6′-SL titers,reaching 3.55 g/L in shake flasks and 15.0 g/L in 3-L fermenters.This study established a foundation for efficient 6′-SL production.
基金supported by the National Natural Science Foundation of China(No.52474053,52474028)Open Fund of Hubei Key Laboratory of Oil and Gas Drilling and Production Engineering(Yangtze University)(No.YQZC202308).
文摘Green-synthesized nanomaterials are anticipated to be extensively applied to inhibit sulfate-reducing bacteria(SRB)in oilfields.Using Bacillus subtilis(B.subtilis)suspension as the raw material and zinc acetate dihydrate(C4H6O4Zn·2H2O)along with silver nitrate(AgNO3)as precursors,Ag-ZnO nanoparticles(NPs)were synthesized using a simple and environment-friendly approach.The resulting Ag-ZnO NPs showed a rough surface morphology combined with high dispersibility,showing a particle size distribution of 33-35 nm.Protease and lipopeptides were identified as potential key agents driving the synthesis of Ag-ZnO NPs.At 40μg/mL,the Ag-ZnO nano-solution effectively inhibited SRB cell growth and reduced the corrosion rate of carbon steel materials induced by SRB.Notably,reactive oxygen species(ROS)and malondialdehyde(MDA)levels increased significantly in SRB cells treated with Ag-ZnO NPs,while cell viability declined,indicating that the nanoparticles caused irreversible damage to SRB biofilms.The inhibitory mechanisms of the NPs against SRB cells were proposed to involve physical electrostatic interactions,metal ion toxicity,cell membrane disruption,and cell lysis.
基金Supported by the Fund of Science and Technology in GuangXi Zhuang Autonomous Region(0009018)~~
文摘[Objective] The aim of this study was to breed new strains which have higher inhibitory effects on the pathogens of watermelon fusarium wilt.[Method] The endophytic Bacillus subtilis B47 strain was obtained from tomato stems by UV mutagenesis for two consecutive times,then genetic stability as well as physiological and biochemical properties of mutant strains were studied.[Result] The antibacterial activity of all the three mutant strains F303,F304 and F305 was higher than that of B74 strain.After subculture of 10 successive generations,the antibacterial activity of all the three mutant strains for the pathogens of watermelon fusarium wilt decreased,but the antibacterial activity of F305 strain decreased the least,indicating its best genetic stability among the tested strains.The antibacterial circle diameter of F305 strain was 5 mm larger than that of wild strain B47 under the same condition.The mutant strain F305 was in logarithmic growth phase within 36 h and in stationary phase within 36-96 h,while its optimum growth temperature was 35 ℃.F305 strain could grow in sodium salt with the concentration of 1%-10%,but it grew best at the concentration of 1%.Physiological and biochemical responses of F305 strain were in accordance with those of wild strain B47.[Conclusion] This study lays the foundation for the factorial production of antagonistic substance by B47 strain and new methods of preventing from the pathogens watermelon fusarium wilt.
基金Supported by 863 Program of China(2006AA03Z0453)NaturalScience Research Program of Higher Education of Jiangsu Province(09KJB230001)+1 种基金973 Program of China(2009CB724700)AndSchool Foundation of Jiangsu University(08JDG009)~~
文摘[ Objective] The research aimed to get the optimized separation and purification conditions of the hirudin produced from Bacillus subtilis DB403 （pUBH5）. [Method] Through the systemic pretreatment, preliminary chromatography and fine chromatography. [Result]The optimized separation and purification conditions were that： Supernatant was treated by trichloroacetic acid, then by ultrafiltration desalt and anion exchange chromatography. Strong anion Q F. F. was better than weak anion DEAE F.F. The proper balanced solution was Tris-HCI （ pH 8.0）. The proper conductivity was 6 ms/cm. The maximum applied sample was 240 ATU/ml to matrix of strong anion Q F. F. This optimized procedure was magnified in strong anion exchange HiPrep 16/10Q with the 90% recovery and 70.2% purity. The purification of gel filtration of Sephacryl S-100 to hirudin was not relative to flow rate within certain scope. The application size of sample was 10 ml. The purity checked by HPLC was 95.1%, and the recovery was 93%, and the band of SDS-PAGE was single. [ Conclusion] The research provided the reference of the further industrialization separation and purification of hiruin.
基金Supported by the"Bud Plan"Project of Beijing Academy of Science and Technology(No.022)~~
文摘[Objective] This study was to investigate the effect of N＋ ion beam implantation on the survival rate and mutation rate of biocontrol strain Bacillus subtilis. [Method] The factors influencing B. subtilis ion beam implantation, including culture time, dilution concentration, solvent, drying time of mycoderm were optimized. B. subtilis cells were implanted by using ion beam at dose of 2.0×10^14～4.0×10^14 ions/cm2 and the energy of 30 kev. Then the methods of culturing colonies confronting each other on plate and Oxford cup diffusion were used to screening strains. [Result] The optimal parameters were found as follows： culture in liquid for 20-24 h, dilution with sterile water to 106 cells/ml and drying time of 60 min for sample preparation; the optimal N＋ ion beam implantation dose of 2.0×10^14～4.0×10^14 ions/cm2 at the energy of 30 kev, the survival rate of 8.43%-26.71% and the mutation rate of 3.50%-5.43%. [Conclusion] This study provided reference for ion beam implantation mutation of B. subtilis.
基金Supported by National"973" Project(2011CB100400)~~
文摘[Objectives] This paper aims to explore the possibility to intercrop garlic with pomegranate tree to control pomegranate wilt.[Methods] Root exudates of garlic is cultivated in 1/5 concentration of MS solution and distilled water is examined in lab to test their effect to growth of mycelia of pomegranate wilt pathogen（Ceratocystis fimbriata）and multiplication of Bacillus subtilis.[Results] The result shows that garlic root exudates whatever cultivated in MS solution or distilled water could not inhibit or promote mycelia growth of C.fimbriata.However,garlic root exudates cultivated in both methods effectively promote multiplication of B.subtilis.[Conclusions] It is suggested that intercropping garlic with pomegranate tree by combining application B.subtilis could be a promising way to prevent pomegranate wilt spread in practice.
基金Supported by Major Scientific and Technological Project in Heilongjiang Province (GA08B101)~~
文摘[ Objective] The paper was to obtain biocontrol strains with good control effects against ginseng soil-borne disease through screening. [ Method] Dilu- tion plate method and plate confrontation culture method were used to isolate and screen biocontrol bacteria from the rhizosphere soil of diseased ginseng. The strains were identified through morphology, physiological and biochemical characteristics and 16S rDNA. [ Result ] With Rhizoctonia solani, Fusarium oxysporum and Fu- sarium solani as the indicator strains, two biocontrol strains B59 and X1 with strong antagonistic effects were screened from the rhizosphere soil of diseased ginseng in Tieli farm of Heilongjiang Province, and they were identified to be Bacillus subtilis. The inhibition rates of two biocontrol strains against eight different fungi were all greater than 90%. The primary study indicated that B59 and X1 strains could secrete antifungal active substances. [ Conclusion] Two biocontrol Bacillus subti- lis strains 1359 and X1 all had strong antagonistic effect against ginseng soil-borne disease, which had certain potential for development and utilization.
基金Supported by the Independent Innovation Fund Project of Agricultural Science and Technology in Jiangsu Province[CX(14)2056]Agricultural Science&Technology Supporting Program of Zhenjiang City(NY2014005)Science and Technology Innovation Items of Jurong City(NY2013026)~~
文摘[Objective] To screen out the biological compound bactericides for grape anthracnose, reduce and replace the use of chemical pesticide. [Methods] The de- termination on the indoor bacteriostatic activity of different proportions of Bacillus subtilis and pyraclostrobin to grape anthracnose was carried out, and mycelial growth rate method was adopted to determine the toxicity of Bacillus subtilis and pyraclostrobin as well as their 5 mixtures to grape anthracnose. [Results] The EC50 of Bacillus subtilis and pyraclostrobin as well as their mixture combinations of 1：1, 1：2, 1：3, 1：4 and 1：5 to grape anthracnose were respectively 1.969 8, 1.527 4, 1.373 2, 1.294 8 and 1.247 3 μg/ml; the synergistic coefficients （SR） of the 5 mix- ture combinations to grape anthracnose were 1.70, 1.25, 1.13, 1.12 and 1.12, re- spectively, in which the synergistic effect of 1：1 was the largest. The indoor biologi- cal activity of pyraclostrobin（EC50 was 1.054 0μg/ml） was higher than that of Bacil- lus subtilis（EC50 was 15.017 5 μg/ml）. 50 d after the agentia（before the harvesting）, the investigation results showed that 1 000-fold dilution, 1 500-fold dilution and 2 000- fold dilution as well as each single dosage of 20% pyraclostrobin .200×10^8 cfu/g Bacillus subtili wettable powder all had better control efficiency to grape anthracnose after fruit setting and before bagging, in which the treatments of high concentration and middle concentration were higher than the treatments of low concentration and two single dosages： the highest control efficiency of high concentration was 90.03%, which was higher than all other treatments; the control efficiency of middle concen- tration was 87.01%, which was higher than that of low concentration and each sin- gle dosage; the control efficiency of low concentration was 84.11%, which was high- er than 1 000-fold dilution of 1 000×10^8 cfu/g Bacillus subti/i wettable powder （the control efficiency was 64.60%） and 2 000-fold dilution of 250 g/L Bacillus subti/i wettable powder （the control efficiency was 81.07%）. In addition, each treatment al- so had better control efficiency to other cluster diseases, such as white rot, etc., and the control efficiency was almost the same as that of anthracnose. [Conclusion] It was suggested that the prevention concentration of 20% pyraclostrobin .200×10^8 cfu/g Bacillus subtili wettable powder to grape anthracnose after fruit setting and before bagging was 1 000-fold - 2 000-fold dilution.
文摘Curing of Bacillus subtilis plasmid using sodium dodecyl sulfate (SDS)was studied in order to obtain a host strain. An overnight culture of Bacillus subtilis 24/pMX45 was used to inoculate fresh LB containing SDS (0-0.008%). No growth of 24/pMX45 was observed when LB contained an SDS concentration of 0.006% or greater, and the sublethal concentration (w/v) of SDS was 0.005% with a killing rate of 99%. Samples were diluted and plated on LB agar, individual colonies were randomly picked to a selective agar medium by tooth to screen for loss of plasmid-encoded erythomycin resistance. CsCl-EtBr gradient centrifugation and plasmid DNA profile demonstrated that plasmid-cured derivative A7 has completely lost its plasmid. A7 had a shorter lag, and its cell concentration was consistently higher than that of the 24/pMX45. Elimination of the plasmid was first observed after 24/pMX45 had been treated with SDS for 8 h. The percent elimination then continued to increase until about 22 h, after which the fraction of cured cell in the population remained constant. Plasmid cured cell numbers were measured in a separate control culture of 24/pMX45 untreated by SDS. No spontaneous loss of pMX45 was observed after 24/pMX45 were incubated for 24 h and 48 h with shaking at 37 ℃.These results suggested that SDS can be used as curing agent to eliminate the plasmid of Bacillus subtilis.
