In recent years, potato scab caused by Streptomyces scabies is aggravating year by year, becoming an industrial problem urgently to be resolved. Screening antagonistic bacteria with good inhibitory effect and wide adaptability is the main measure to realize effective prevention and control of the disease. This study screened three strains of antagonistic bacteria DXT2-4, T2-1 and 21-14 with good inhibitory effect on S. scabies by using plate standoff test, and identified them as Bacillus altitudinis, Bacillus safensis and Bacillus pumilus, respectively, based on morphological characteristics, physiological and biochemical properties, and 16S rRNA gene sequences. DXT2-4, T2-1 and 21-14 showed the pot control efficacy of 68.83%, 48.57%, and 57.14%, respectively. The field control efficacy of the three strains was 59.48%, 34.58% and 51.75% in Hulun Buir, Inner Mongolia Autonomous Region and 55.14%, 36.05%, and 49.05% in Huizhou, Guangdong. The three strains could grow normally in the media with pH 1.0-13.0 and with 1%-11% NaCl, and they had inhibitory effects on Rhizoctonia solani, Verticillium dahliae, Alternaria solani, and Fusarium oxysporum. The indole-3-acetic acid yields of DXT2-4, T2-1, and 21-14 were 2.23, 1.11, and 1.67 mg/L, respectively. DXT2-4 and 21-14 demonstrated strong abilities to solubilize phosphorus. The optimal carbon source, nitrogen source, and inorganic salt for fermentation of strain DXT2-4 were 2% molasses+2% corn starch, 2% soybean meal, and 0.3% MgSO₄·7H₂O, respectively. These findings suggest the three strains of bacteria can efficiently inhibit the growth of S. scabies and have strong environmental adaptability. Particularly, DXT2-4 has the best effects of inhibiting the disease and promoting plant growth, showing a high development value and broad application prospects, this is of great significance for promoting sustainable potato production and ensuring the environmentally sound utilization of resources.
Streptomyces/metabolism* ; Fermentation ; Plant Diseases/prevention & control* ; Solanum tuberosum/growth & development* ; Bacillus/growth & development* ; Antibiosis

Mycobacterium (M.) vaccae is a fast-growing species of saprophytic bacteria that is widely distributed. To understand the host immune responses induced by M. vaccae isolated from bovine submaxillary lymph nodes, C57BL/6 mice were infected with reference strain M. vaccae Bacillus Calmette-Guérin (BCG) and isolated M. vaccae using intraperitoneal injections. Comparison of the bacterial replication and organ pathology between M. vaccae and M. vaccae BCG revealed that M. vaccae was more malignant than M. vaccae in mice. We also demonstrated that serum from the M. vaccae-infected mice contained a higher expression level of gamma-interferon (IFN-γ), tumor necrosis factor alpha, monocyte chemoattractant protein-1, interleukin (IL)-4, IL-12, IL-10 and transforming growth factor beta than did the other groups, especially after week 4. Furthermore, when the numbers of CD3⁺CD4⁺IFN-γ⁺ and CD3⁺CD4⁺IL4⁺ cells in the infected mice were observed by flow cytometry, we found that a powerful T helper 1 (Th1) response was induced by M. vaccae infection, which was associated with the emergence of CD3⁺CD4⁺IFN-γ⁺ cells. However, the Th1 response declined over time, which was associated with appearance of the CD4⁺CD25⁺FoxP3⁺ and CD4⁺CD25⁺CD152⁺Treg cell reaction. In addition, a strong Th2 response was found. Finally, we found that M. vaccae infection increased the production of type I IFNs, which was associated with a reduced Th1 response.
Animals ; Bacillus ; Bacteria ; Chemokine CCL2 ; Flow Cytometry ; Injections, Intraperitoneal ; Interferon-gamma ; Interleukin-10 ; Interleukin-12 ; Interleukins ; Lymph Nodes ; Mice* ; Mycobacterium bovis ; Mycobacterium* ; Pathology ; Transforming Growth Factor beta ; Tumor Necrosis Factor-alpha

To reveal the colonization characteristics in host of endophytic biocontrol bacteria NJ13 isolated from Panax ginseng, this study obtained the marked strain NJ13-R which was double antibiotic resistant to rifampicin and streptomycin through enhancing the method of inducing antibiotic. The colonization characteristics in ginseng and its biocontrol efficiency against Alternaria spot of ginseng in the field were studied. The results showed that the strain could colonize in root, stem and leaf of ginseng and the colonization amount was positive correlated with inoculation concentration. Meanwhile, the strain could infect and then transfer in different tissues of ginseng The colonization amount of strain in roots and leaves of ginseng increased first and then decreased. However, the tendency of colonization amount of strain in stems was ascend at first and then descend slowly, and was more than that in roots and leaves along with time, which had a preference to specific tissue of its host. In field experiment, the endophytic bacteria NJ13 was proved to be effective in controlling Alternaria leaf spot of ginseng. The biocontrol efficiency of fermentation broth at the concentration of 0.76 x 10(8) cfu x mL(-1) reached 75.62%, which was close to the controlling level (73.06%) of 0.67 mg x L(-1) 50% cyprodinil WG.
Alternaria ; physiology ; Antibiosis ; Bacillus ; growth & development ; isolation & purification ; physiology ; Endophytes ; growth & development ; isolation & purification ; physiology ; Panax ; growth & development ; microbiology ; Plant Diseases ; microbiology

The anti-bacterial activities of three types of di-O-caffeoylquinic acids (diCQAs) in Lonicera japonica flowers, a traditional Chinese medicine (TCM), on Bacillus shigae growth were investigated and compared by microcalorimetry. The three types of diCQAs were 3, 4-di-O-caffeoylquinic acid (3, 4-diCQA), 3, 5-di-O-caffeoylquinic acid (3, 5-diCQA), and 4, 5-di-O-caffeoylquinic acid (4, 5-diCQA). Some qualitative and quantitative information of the effects of the three diCQAs on metabolic power-time curves, growth rate constant k, maximum heat-output power Pm, and the generation time tG, total heat output Qt, and growth inhibitory ratio I of B. shigae were calculated. In accordance with a thermo-kinetic model, the corresponding quantitative relationships of k, Pm, Qt, I and c were established. Also, the half-inhibitory concentrations of the drugs (IC50) were obtained by quantitative analysis. Based on the quantity-activity relationships and the IC50 values, the sequence of inhibitory activity was 3, 5-diCQA > 4, 5-diCQA > 3, 4-diCQA. The results illustrate the possibility that the caffeoyl ester group at C-5 is the principal group that has a higher affinity for the bacterial cell, and that the intramolecular distance of the two caffeoyl ester groups also has an important influence on the anti-bacterial activities of the diCQAs.
Anti-Bacterial Agents ; pharmacology ; Bacillus ; drug effects ; growth & development ; Chlorogenic Acid ; analogs & derivatives ; chemistry ; pharmacology ; Drugs, Chinese Herbal ; pharmacology ; Flowers ; chemistry ; Inhibitory Concentration 50 ; Lonicera ; chemistry ; Monosaccharides ; chemistry ; pharmacology ; Quinic Acid ; analogs & derivatives ; chemistry ; pharmacology

Biosurfactants (BSs) are highlighted owing to their multiple advantages in diverse applications. To screen a superior strain that producing a blend-biosurfactant of lipopeptide and glycolipid, the hemolytic activity assay on blood agar plates, the modified oil-red spreading test and MALDI-TOF Mass Spectrometry identification of the purified products was carried out. Bacillus subtilis THY-7 was selected and its principal products were surfactin and dirhamnolipid. The medium component and culture conditions of THY-7 were optimized by both single factor and orthogonal experiments. After 48 h optimal batch culture in flask, the cell density (OD600) was 37.0 and the product titer was 2.4 g/L, which was 3.4 folds and 3.1 folds of that under original condition, respectively. A fed-batch culture in a 5 L fermentor was further performed coupling with in situ recovery of foam, in which the titer of blend-BS increased to 4.5 g/L at 25 h. Quantification by HPLC and anthrone colorimetry revealed that surfactin and dirhamnolipid accounted for 74% and 22% of the blend-BS, respectively.
Bacillus subtilis ; growth & development ; isolation & purification ; metabolism ; Chromatography, High Pressure Liquid ; Culture Media ; Glycolipids ; biosynthesis ; Industrial Microbiology ; Lipopeptides ; biosynthesis ; Surface-Active Agents ; metabolism

In this study, we investigated the mechanism of transformation by Bacillus subtilis strain 168 by proteomic analysis. B. subtilis strain 168 was able to stereoselectively transform cis-propenylphosphonic acid (cPPA) to fosfomycin. The maximal fosfomycin production was 816.6 microg/mL after two days cultivation, with a conversion rate of 36.05%. We separated the whole cellular proteins by two-dimensional gel electrophoresis (2-DE) method, and 562 protein spots were detected in the presence of cPPA in the medium, while 527 protein spots were detected in the absence of cPPA. Of them, 98 differentially expressed protein spots were found. Among them, 52 proteins were up-regulated whereas 20 were down-regulated in the presence of cPPA in the medium, and 26 induced at the presence of cPPA. The differentially expressed proteins were analyzed by combined MS and MS/MS methods. Eighty protein spots, including 45 up-regulated proteins, 17 down-regulated proteins, and 18 induced by cPPA were identified. Based on the results of proteomic analysis, we postulated two steps of transformation: in the first step, cPPA was hydrated to 2-hydroxypropylphosphonic acid; in the second step, 2-hydroxypropylphosphonic acid was transformed to fosfomycin via a dehydrogenation reaction.
Bacillus subtilis ; genetics ; growth & development ; metabolism ; Bacterial Proteins ; metabolism ; Biotransformation ; Fosfomycin ; metabolism ; Organophosphorus Compounds ; metabolism ; Proteome ; metabolism ; Proteomics

Thrombus disease, one of the common cardiovascular diseases, has attracted worldwide attention for its rising mortality and morbidity. Due to the distinct shortages of current fibrinolytic drugs, new fibrinolytic agents warrant investigation. In this study, 8 fibrinolytic enzyme-producing strains were isolated from Douchi-a traditional Chinese food, and strain XY-1 which produced the largest amount of the enzyme was chosen for the following experiments. The enzyme produced by strain XY-1 was named Douchi fibrinolytic enzyme (DFE). We optimized the liquid culture medium of strain XY-1 for enzyme production using Plackett-Burman and Box-Behnken design. The predicted maximal DFE yield was 19.78 FU/mL with 11.4 g/L peptone, 0.5 g/L magnesium sulfate and 1 g/L sodium chloride. However, we acquired maximal production of 21.33 FU/mL in actual experiments, equal to 107.84% of the theoretical value, and the yield had been increased by 79.55% as compared to the yield of un-optimized culture. It was demonstrated that the combined use of Plackett-Burman design and response surface methodology in fermentation optimization can effectively and rapidly increase DFE production.
Bacillus ; physiology ; Bioreactors ; microbiology ; Blood Coagulation ; drug effects ; physiology ; Cells, Cultured ; Combinatorial Chemistry Techniques ; Computer Simulation ; Fabaceae ; enzymology ; growth & development ; microbiology ; Fibrinolytic Agents ; isolation & purification ; metabolism ; pharmacology ; Humans ; Models, Biological ; Models, Statistical

PeaT1, a protein elicitor from Alternaria tenuissima can promote plant growth and trigger systemic acquired resistance in plants. In order to expand the application of PeaT1, P43 promoter sequence and nprB signal peptide-encoding sequence were cloned from Bacillus subtilis 168 chromosomal DNA. The two sequences and peaT1 gene were spliced by overlapping extension. This product was cloned into the Escherichia coli-B. subtilis shuttle vector pHY300-PLK and the resultant recombinant expression vector (pHY43N- peaTI) plasmid was transformed into B. subtilis WB800. SDS-PAGE and Western blotting analysis showed that protein elicitor PeaT1 was expressed extracellularly in B. subtilis. This recombinant bacterial strain enhanced drought tolerance and promoted seedling growth in wheat.
Adaptation, Physiological ; drug effects ; Alternaria ; chemistry ; genetics ; Bacillus subtilis ; genetics ; metabolism ; Droughts ; Fungal Proteins ; biosynthesis ; genetics ; Genetic Vectors ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Triticum ; growth & development

To compare the microcalorimetric fingerprint profiles of Lonicerae japonicae Flos (Lj.F) and Lonicerae Flos (L.F), microcalormietry was applied to find the heat change regularity of Bacillus shigae (B. shigae) metabolism affected by Lj.F and L.F (we choose Lonicera macranthoides Hand.-Mazz in this paper) with different concentrations. The thermogenic curves and thermodynamics parameters were investigated as evaluation index, and then the date of experiment was studied by similarity analysis. All the results indicated that the Lj.F and Lonicera macranthoides Hand.-Mazz (L.m.H-M) significantly impacted the microbial growth and had good similarity in its inhibitory activities. The combination approach of chemical analysis with bioassay was developed and employed to ensure the safety and efficacy of Chinese herbal medicines.
Anti-Bacterial Agents ; isolation & purification ; pharmacology ; Bacillus ; drug effects ; growth & development ; Calorimetry ; methods ; Chemical Safety ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Flowers ; chemistry ; Lonicera ; chemistry ; classification ; Plants, Medicinal ; chemistry ; classification ; Quality Control ; Thermodynamics ; Thermogenesis

Chitinases were produced by a lot of microorganisms. Chitinase gene expression in most of the chitinase producing bacteria was inducible by chitin. Low levels of chitinase were observed in the presence of glucose. To date, however, the regulation of such chitinase gene in Bacillus thuringiensis had not been well studied. In this paper, all 77 Bacillus thuringiensis strains were grown in the medium with or without chitin. We measured quantitatively the chitinase activity of the cultures. Moreover, we investigated the suppressive effect of glucose on chitinase of 4 strains. Also we studied the relationship between chitin induction and glucose suppression on chitinase. This investigation demonstrated that all tested B. thuringiensis strains could produce chitinase without chitin. After induction, the chitinolytic activity of 31 tested strains had no obvious response to the inducer, whereas 44 stains increased in different degree. Among these strains, most of them did not markedly increase the levels of chitinase, and many stains simultaneously displayed the expression mode of inducible and constitutive. The glucose inhibited the inductive effect of chitin, but it could not inhibit the basal expression of chitinase. Two strains No. 38 and No. 75 belonged to different expression types. But we just found several different bases in the regulatory region of chitinase genes chiA and chiB from them.
Bacillus thuringiensis ; enzymology ; growth & development ; Base Sequence ; Chitin ; pharmacology ; Chitinases ; biosynthesis ; genetics ; Culture Media ; chemistry ; Culture Techniques ; Glucose ; pharmacology ; Molecular Sequence Data ; Polymorphism, Genetic