Bacillus is a class of spore-producing Gram-positive bacteria that produce a variety of antimicrobial substances with different structures and functions. The application of the antimicrobial substances produced by Bacillus can effectively inhibit the activity of harmful bacteria and fungi and promote the sustainable development of green agriculture. The antimicrobial substances produced by Bacillus mainly include proteins, lipopeptides, polyketones, and polypeptides. This paper reviews the synthesis gene clusters, synthesis pathways, structures, and mechanisms of various antimicrobial substances produced by Bacillus and discusses the challenges in the industrial application of these antimicrobial substances. Furthermore, this paper clarifies the future research and development focuses and prospects the application prospects, and provides comprehensive theoretical support for the in-depth research and wide application of the antimicrobial substances produced by Bacillus.
Bacillus/genetics* ; Anti-Infective Agents/metabolism* ; Bacterial Proteins/genetics* ; Antimicrobial Peptides/biosynthesis* ; Lipopeptides/biosynthesis*

Antimicrobial peptides (AMPs) are small molecular peptides widely existing in the innate immunity of organisms, serving as the first line of defense. Natural AMPs possess various biological activities and are difficult to develop drug resistance. However, they are easily broken down by digestive enzymes in the body. In recent years, increasing methods have been reported to enhance the stability of AMPs, including incorporation of unnatural amino acids, chemical modifications, strategic avoidance of enzyme cleavage sites, cyclization, and nano peptide design. This review summarizes the methods for improving the stability of AMPs against protease degradation, aiming to provide references for further research in this field.
Antimicrobial Peptides/pharmacology* ; Humans ; Peptide Hydrolases/metabolism* ; Protein Stability ; Antimicrobial Cationic Peptides/chemistry* ; Anti-Infective Agents/chemistry*

From the fungus Trichoderma sp., we isolated seven novel 18-residue peptaibols, neoatroviridins E-K (1-7), and six new 14-residue peptaibols, harzianins NPDG J-O (8-13). Additionally, four previously characterized 18-residue peptaibols neoatroviridins A-D (14-17) were also identified. The structural configurations of the newly identified peptaibols (1-13) were determined by comprehensive nuclear magnetic resonance (NMR) and high-resolution electrospray ionization tandem mass spectrometry (HR-ESI-MS/MS) data. Their absolute configurations were further determined using Marfey's method. Notably, compounds 12 and 13 represent the first 14-residue peptaibols containing an acidic amino acid residue. In antimicrobial assessments, all 18-residue peptaibols (1-7, 14-17) exhibited moderate inhibitory activities against Staphylococcus aureus 209P, with minimum inhibitory concentration (MIC) values ranging from 8-32 μg·mL^-1. Moreover, compound 9 exhibited moderate inhibitory effect on Candida albicans FIM709, with a MIC value of 16 μg·mL^-1.
Peptaibols/chemistry* ; Trichoderma/metabolism* ; Tandem Mass Spectrometry/methods* ; Anti-Infective Agents/pharmacology* ; Spectrometry, Mass, Electrospray Ionization/methods*

Efforts to control inflammation and achieve better tissue repair in the treatment of periodontitis have been ongoing for years. Human β-defensin 3, a broad-spectrum antimicrobial peptide has been proven to have a variety of biological functions in periodontitis; however, relatively few reports have addressed the effects of human periodontal ligament cells (hPDLCs) on osteogenic differentiation. In this study, we evaluated the osteogenic effects of hPDLCs with an adenoviral vector encoding human β-defensin 3 in an inflammatory microenvironment. Then human β-defensin 3 gene-modified rat periodontal ligament cells were transplanted into rats with experimental periodontitis to observe their effects on periodontal bone repair. We found that the human β-defensin 3 gene-modified hPDLCs presented with high levels of osteogenesis-related gene expression and calcium deposition. Furthermore, the p38 MAPK pathway was activated in this process. In vivo, human β-defensin 3 gene-transfected rat PDLCs promoted bone repair in SD rats with periodontitis, and the p38 mitogen-activated protein kinase (MAPK) pathway might also have been involved. These findings demonstrate that human β-defensin 3 accelerates osteogenesis and that human β-defensin 3 gene modification may offer a potential approach to promote bone repair in patients with periodontitis.
Animals ; Anti-Infective Agents ; metabolism ; pharmacology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Humans ; Osteogenesis ; drug effects ; Periodontal Ligament ; drug effects ; metabolism ; Periodontitis ; drug therapy ; Rats ; Rats, Sprague-Dawley ; beta-Defensins ; metabolism ; pharmacology

OBJECTIVE: To investigate the molecular mechanisms of the adverse effects of exposure to sulfamonomethoxin (SMM) in pregnancy on the neurobehavioral development of male offspring. METHODS: Pregnant mice were randomly divided into four groups: control- (normal saline), low- [10 mg/(kg•day)], middle- [50 mg/(kg•day)], and high-dose [200 mg/(kg•day)] groups, which received SMM by gavage daily during gestational days 1-18. We measured the levels of short-chain fatty acids (SCFAs) in feces from dams and male pups. Furthermore, we analyzed the mRNA and protein levels of genes involved in the mammalian target of rapamycin (mTOR) pathway in the hippocampus of male pups by RT-PCR or Western blotting. RESULTS: Fecal SCFA concentrations were significantly decreased in dams. Moreover, the production of individual fecal SCFAs was unbalanced, with a tendency for an increased level of total fecal SCFAs in male pups on postnatal day (PND) 22 and 56. Furthermore, the phosphatidylinositol 3-kinase (PI3k)/protein kinase B (AKT)/mTOR or mTOR/ribosomal protein S6 kinase 1 (S6K1)/4EBP1 signaling pathway was continuously upregulated until PND 56 in male offspring. In addition, the expression of Sepiapterin Reductase (SPR), a potential target of mTOR, was inhibited. CONCLUSION In utero exposure to SMM, persistent upregulation of the hippocampal mTOR pathway related to dysfunction of the gut (SCFA)-brain axis may contribute to cognitive deficits in male offspring.
Alcohol Oxidoreductases ; metabolism ; Animals ; Anti-Infective Agents ; toxicity ; Fatty Acids, Volatile ; analysis ; Feces ; chemistry ; Female ; Hippocampus ; drug effects ; metabolism ; Male ; Memory ; drug effects ; Mice, Inbred ICR ; Pregnancy ; Prenatal Exposure Delayed Effects ; Sulfamonomethoxine ; toxicity ; TOR Serine-Threonine Kinases ; metabolism

OBJECTIVEMyanmar has a long history of using medicinal plants for treatment of various diseases. To the best of our knowledge there are no previous reports on antiglycation activities of medicinal plants from Myanmar. Therefore, this study was aimed to evaluate the antioxidant, antiglycation and antimicrobial properties of 20 ethanolic extracts from 17 medicinal plants indigenous to Myanmar.

METHODSIn vitro scavenging assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), superoxide (SO) radicals were used to determine the antioxidant activities. Folin-Ciocalteu's method was performed to determine the total phenolic content. Antiglycation and antimicrobial activities were detected by bovine serum albumin-fluorescent assay and agar well diffusion method.

RESULTSTerminalia chebula Retz. (Fruit), containing the highest total phenolic content, showed high antioxidant activities with inhibition of 77.98% ± 0.92%, 88.95% ± 2.42%, 88.56% ± 1.87% and 70.74%± 2.57% for DPPH, NO, SO assays and antiglycation activity respectively. It also showed the antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans with inhibition zone of 19, 18, 17, 25 and 15 mm, respectively. Garcinia mangostana Linn. showed the strongest activities for SO and antiglycation assays with inhibition of 93.68% ± 2.63% and 82.37% ± 1.78%. Bark of Melia sp. was the best NO radical scavenger with inhibition rate of 89.39%± 0.60%.

CONCLUSIONThe results suggest that these plants are potential sources of antioxidants with free radical-scavenging and antiglycation activities and could be useful for decreasing the oxidative stress and glycation end-product formation in glycation-related diseases.

Anti-Bacterial Agents ; analysis ; pharmacology ; Anti-Infective Agents ; analysis ; pharmacology ; Antioxidants ; analysis ; pharmacology ; Bacteria ; drug effects ; growth & development ; Biphenyl Compounds ; metabolism ; Candida albicans ; drug effects ; growth & development ; Fruit ; Garcinia ; chemistry ; Glycation End Products, Advanced ; metabolism ; Humans ; Magnoliopsida ; chemistry ; Medicine, Traditional ; Melia ; chemistry ; Myanmar ; Nitric Oxide ; metabolism ; Oxidative Stress ; drug effects ; Phenols ; analysis ; pharmacology ; Phytotherapy ; Picrates ; metabolism ; Plant Bark ; Plant Extracts ; chemistry ; pharmacology ; Plants, Medicinal ; Superoxides ; Terminalia ; chemistry

OBJECTIVETo investigate the application of bundles of intervention in the treatment of esophageal carcinoma anastomotic leak.

METHODSFrom January 2014 to May 2015, 44 cases of esophageal carcinoma anastomotic fistula were treated by bundles of intervention (through the collection of a series of evidence-based treatment and care measures for the treatment of diseases) in Department of Thoracic Surgery, Huai'an First Hospital, Nanjing Medical University (bundles of intervention group), and 68 patients with esophageal carcinoma postoperative anastomotic leak from December 2013 to January 2012 receiving traditional therapy were selected as the control group. The clinical and nutritional indexes of both groups were compared.

RESULTSThere were no significant differences in general data and proportion of anastomotic leak between the two groups. Eleven patients died during hospital stay, including 3 cases in bundles of intervention group(6.8%) and 8 cases in control group (11.8%) without significant difference(P = 0.390). In bundles of intervention group, 1 case died of type III( intrathoracic anastomotic leak, 2 died of type IIII( intrathoracic anastomotic leak. In control group, 2 cases died of type III( cervical anastomotic leak, 2 died of type III( intrathoracic anastomotic leak and 4 of type IIII( intrathoracic anastomotic leak. The mortality of bundles of intervention group was lower than that of control group. The duration of moderate fever [(4.1±2.4) days vs. (8.3±4.4) days, t=6.171, P=0.001], the time of antibiotic use [(8.2±3.8) days vs.(12.8±5.2) days, t=5.134, P = 0.001], the healing time [(21.5±12.7) days vs.(32.2±15.8) days, t=3.610, P=0.001] were shorter, and the average hospitalization expenses[(63±12) thousand yuan vs. (74±19) thansand yuan, t=3.564, P=0.001] was lower in bundles of intervention group than those in control group. Forty-eight hours after occurrence of anastomotic leak, the levels of hemoglobin, albumin and prealbumin were similar in both groups. However, at the time of fistula healing, the levels of hemoglobin [(110.6±10.5) g/L vs.(103.8±11.1) g/L, t=3.090, P=0.002], albumin [(39.2±5.2) g/L vs.(36.3±5.9) g/L, t=2.543, P=0.013] and prealbumin [(129.3±61.9) g/L vs.(94.1±66.4) g/L, t=2.688, P=0.008] were significantly higher in bundles of intervention group.

CONCLUSIONIn the treatment of postoperative esophageal carcinoma anastomotic leak, application of bundles of intervention concept can significantly improve the nutritional status and improve the clinical outcomes.

Anastomotic Leak ; mortality ; therapy ; Anti-Infective Agents ; therapeutic use ; Carcinoma ; complications ; surgery ; Esophageal Fistula ; complications ; mortality ; therapy ; Esophageal Neoplasms ; complications ; surgery ; Esophagectomy ; adverse effects ; mortality ; Female ; Fever ; epidemiology ; etiology ; Hemoglobins ; metabolism ; Hospital Costs ; statistics & numerical data ; Humans ; Male ; Middle Aged ; Nutritional Status ; Patient Care Bundles ; mortality ; statistics & numerical data ; Prealbumin ; metabolism ; Serum Albumin ; metabolism ; Treatment Outcome

BACKGROUND: Extensively drug-resistant (XDR) Pseudomonas aeruginosa and Acinetobacter baumannii are a threat to hospitalized patients. We evaluated the effects of antimicrobial combinations on XDR P. aeruginosa and A. baumannii isolates. METHODS: P. aeruginosa and A. baumannii isolates, which were resistant to all antibiotics except colistin (CL), were collected from eight hospitals in Korea. Genes encoding metallo-beta-lactamases (MBLs) and OXA carbapenemases were detected by PCR in eight P. aeruginosa and 30 A. baumannii isolates. In vitro synergy of antimicrobial combinations was tested by using the checkerboard method. RESULTS: Minimum inhibitory concentrations of beta-lactams, aminoglycosides, and fluoroquinolones were very high, while that of CL was low for majority of XDR P. aeruginosa and A. baumannii isolates. Antimicrobial combinations including Imipenem (IPM)-CL, ceftazidime (CAZ)-CL, and rifampin (RIF)-CL exerted only additive/indifferent effects on majority of XDR P. aeruginosa isolates. Proportions of XDR A. baumannii isolates that showed synergistic and additive/indifferent inhibition after treatment with antimicrobial combinations used are as follows: IPM-ampicillin-sulbactam (AMS), 17% and 80% isolates, respectively; IPM-rifampin (RIF), 13% and 81% isolates, respectively; IPM-CL, 13% and 87% isolates, respectively; and RIF-COL, 20% and 73% isolates, respectively. Significant proportion (19%) of XDR P. aeruginosa isolates produced MBLs, and majority (82%) of A. baumannii isolates produced either MBLs or OXA-23. CONCLUSIONS: Our results suggest that combinations of IPM-AMS, IPM-RIF, IPM-CL, and RIF-CL are more useful than individual drugs for treating 13-20% of XDR A. baumannii infections.
Acinetobacter baumannii/*drug effects/genetics/isolation & purification ; Aminoglycosides/pharmacology ; Anti-Infective Agents/*pharmacology ; Bacterial Proteins/genetics/metabolism ; Drug Resistance, Multiple, Bacterial/*drug effects ; Drug Synergism ; Fluoroquinolones/pharmacology ; Imipenem/pharmacology ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Pseudomonas aeruginosa/*drug effects/genetics/isolation & purification ; beta-Lactamases/genetics/metabolism

BACKGROUND: We evaluated the reliability and accuracy of the combined use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) bacterial identification and Vitek 2 antimicrobial susceptibility testing (AST) for bacteria from positive blood culture bottles. METHODS: Direct identification and AST were performed in parallel to the standard methods in monomicrobial positive blood culture bottles. In total, 254 isolates grown on aerobic and/or anaerobic bottles were identified with MALDI-TOF Vitek MS (bioMerieux, France), and 1,978 microorganism/antimicrobial agent combinations were assessed. For isolates from anaerobic bottles, an aliquot of the culture broth was centrifuged, washed, and filtered through a nylon mesh. For isolates from aerobic/pediatric bottles, a lysis step using 9.26% ammonium chloride solution and 2% saponin solution was included. RESULTS: The overall correct identification rate was 81.8% (208/254) and that for gram-positive/gram-negative isolates was 73.9%/92.6%, respectively, and it was 81.8%, 87.6%, and 57.9% for isolates from aerobic, anaerobic, and pediatric bottles, respectively. Identification was not possible in 45 cases, and most of these isolates were streptococci (N=14) and coagulase-negative staphylococci (N=11). Misidentification occurred only in one case. Compared with standard methods, direct AST showed 97.9% (1,936/1,978) agreement with very major error of 0.25%, major error of 0.05%, and minor error of 1.8%. CONCLUSIONS: This simple and cost-effective sample preparation method gives reliable results for the direct identification and AST of bacteria. For the identification of streptococci and coagulase-negative staphylococci, the method should be further improved.
Adult ; Ammonium Chloride/chemistry ; Anti-Infective Agents/*pharmacology ; Child ; Gram-Negative Bacteria/drug effects/*isolation & purification/metabolism ; Gram-Positive Bacteria/drug effects/*isolation & purification/metabolism ; Humans ; Reagent Kits, Diagnostic ; Saponins/chemistry ; *Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

BACKGROUND: The development of new drugs or alternative therapies effective against methicillin-resistant Staphylococcus aureus (MRSA) is of great importance, and various natural anti-MRSA products are good candidates for combination therapies. We evaluated the antibacterial activities of a Phellinus baumii ethyl acetate extract (PBEAE) and its synergistic effects with beta-lactams against MRSA. METHODS: The broth microdilution method was used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the PBEAE. The PBEAE synergistic effects were determined by evaluating the MICs of anti-staphylococcal antibiotic mixtures, with or without PBEAE. Anti-MRSA synergistic bactericidal effects of the PBEAE and beta-lactams were assessed by time-killing assay. An ELISA was used to determine the effect of the PBEAE on penicillin binding protein (PBP)2a production. RESULTS: The MICs and MBCs of PBEAE against MRSA were 256-512 and 1,024-2,048 microg/mL, respectively. The PBEAE significantly reduced MICs of all beta-lactams tested, including oxacillin, cefazolin, cefepime, and penicillin. However, the PBEAE had little or no effect on the activity of non-beta-lactams. Time-killing assays showed that the synergistic effects of two beta-lactams (oxacillin and cefazolin) with the PBEAE were bactericidal in nature (Deltalog10 colony forming unit/mL at 24 hr: 2.34-2.87 and 2.10-3.04, respectively). The PBEAE induced a dose-dependent decrease in PBP2a production by MRSA, suggesting that the inhibition of PBP2a production was a major synergistic mechanism between the beta-lactams and the PBEAE. CONCLUSIONS: PBEAE can enhance the efficacy of beta-lactams for combined therapy in patients infected with MRSA.
Acetates/chemistry ; Agaricales/*chemistry/metabolism ; Anti-Infective Agents/chemistry/*pharmacology ; Drug Synergism ; Enzyme-Linked Immunosorbent Assay ; Methicillin-Resistant Staphylococcus aureus/*drug effects/metabolism ; Microbial Sensitivity Tests ; Penicillin-Binding Proteins/analysis/metabolism ; Plant Extracts/chemistry/*pharmacology ; beta-Lactams/*pharmacology