ABSTRACT
BACKGROUND: It has been confirmed that some biomedical magnesium alloy products have antibacterial properties, but the specific antibacterial mechanism is still unclear. OBJECTIVE: To investigate the antibacterial properties of biomedical Jiao Da Bio-Magnesium scaffold in vitro and explore possible mechanism. METHODS: Jiao Da Bio-Magnesium porous scaffold material extract was prepared. As the most common bacteria causing orthopedic implants infection, Escherichia coli and Staphylococcus aureus were selected for testing. The bacteriostasis rate was quantitatively evaluated by contact culture of the extraction solution. The bacteriostasis performance of the material was qualitatively evaluated by observing the bacterial morphology through scanning electron microscope. The alkaline phosphatase, conductivity, potassium ion, nucleic acid and protein content in bacterial extracellular liquid environment were detected. The possible antibacterial mechanism of Jiao Da Bio-Magnesium porous scaffold material extract was preliminarily explored. RESULTS AND CONCLUSION: (1) The bacteriostasis rate of Jiao Da Bio-Magnesium porous scaffold extract cultured with Escherichia coli for 12 hours ranged from 56.23% to 79.72%, while the Staphylococcus aureus group ranged from 62.34% to 76.07%. (2) Under scanning electron microscope, wizened form, smaller volume and scarcer distribution were observed. (3) The material extract had no effect on the content of alkaline phosphatase in the extracellular environment of the two bacteria, but increased the electrical conductivity and potassium ion content in the extracellular environment of the two bacteria. (4) The material extract had no effect on the content of nucleic acid and protein in the extracellular environment of Escherichia coli, and increased the content of nucleic acid and protein in the extracellular environment of Staphylococcus aureus. (5) The material extract could inhibit the nucleic acid content of the two bacteria, but had no effect on the soluble protein content of Escherichia coli cells, and inhibited the synthesis of soluble protein in Staphylococcus aureus cells. (6) Results suggested that Jiao Da Bio-Magnesium porous scaffold material has certain antibacterial properties in vitro, and the inhibitory effect on Staphylococcus aureus is stronger than that on Escherichia coli. The possible antibacterial mechanism is speculated that it can change the permeability of bacterial cell membrane and affect the synthesis of bacterial nucleic acids and proteins.
ABSTRACT
Due to worldwide abuse of chemical antibiotics and continuous emergence of "superbugs", the harm of bacterial drug resistance to human beings has become more and more serious. Therefore, it is of great significance to look for green antibiotics with a wide range of sources, broad antibacterial spectrum, non-toxicity or low toxicity, environmentally friendliness, diverse active components and low drug resistance. The volatile oil of traditional Chinese medicine is a kind of volatile oily liquid that exists in plants and can be distilled with steam and immiscible with water. Because of its good potential to resist drug-resistant pathogens, it is widely used in food, medicine and other fields. This paper summarized the antibacterial advantages and characteristics of volatile oil of traditional Chinese medicine, and the antibacterial effect and antibacterial mechanism of combined application of volatile oil of traditional Chinese medicine, in order to provide some theoretical basis and study ideas for solving the problem of bacterial drug resistance and developing natural and green antibiotics.
Subject(s)
Humans , Anti-Bacterial Agents/pharmacology , Anti-Infective Agents , Drugs, Chinese Herbal/pharmacology , Medicine, Chinese Traditional , Oils, Volatile/pharmacologyABSTRACT
We prepared moxifloxacin (MXF) loaded nanoparticles by nano-precipitation/self-assembly method, then compared the antibacterial activity of MXF and MXF loaded nanoparticles, and investigated the antibacterial mechanism of MXF loaded nanoparticles against Pseudomonas aeruginosa in vitro. The physicochemical properties such as particle size and zeta potential were investigated by laser particle size analyzer. The in vitro release characteristics were investigated by high performance liquid chromatography (HPLC). The effect of nanoparticles on HBE cells viability was investigated by CCK-8 assay. In addition, the in vitro antibacterial activity was investigated by minimum inhibitory concentration (MIC) assay, biofilm formation assays and transmission electron microscope (TEM) observation, then the antibacterial mechanism was initially explored. The particle size measurement showed that the nanoparticles had a size of 332.5 ± 2.7 nm, a polymer dispersion index (PDI) of 0.125 ± 0.053, a zeta potential of -24.3 ± 1.7 mV, and a uniform particle size distribution, drug loading content was (6.02 ± 1.27) %, encapsulation efficiency was (16.69 ± 1.17) %. The TEM results show that the nanoparticles have a spheroidal structure, and the particle size and distribution are consistent with the particle size measurement results. The nanoparticles can be effectively and rapidly released in phosphate buffer saline (PBS), releasing about 70% in 24 h, and releasing 87% in 72 h, and almost completely releasing the MXF at 120 h. At the same time, compared with moxifloxacin free drug, its MIC value is 8 μg·mL-1, which is 1/2 of MXF solution, and can significantly inhibit the formation of bacterial biofilms. It has well antibacterial activity in vitro and can be targeted to the surface of bacteria to exert its efficacy and improve the antibacterial effect. The moxifloxacin nanoparticles prepared in this study has a uniform particle size distribution, well drug release performance and antibacterial effect, and provides new ideas and strategies for the treatment of bacterial lung infection and the development of new antibacterial nanoformulations.
ABSTRACT
Nanometer zinc oxide has become a new hotspot in the research of tissue engineering materials due to its excellent antibacterial properties, biocompatibility, and anti-tumor properties. In this paper, the existing research results were summarized, generalized, and analyzed. The antibacterial mechanism of nanometer zinc oxide was discussed in depth. The antibacterial properties and advantages of the latest nanometer zinc oxide composite materials were introduced in detail. In this review, we made prospect of the future application of nanometer zinc oxide.
ABSTRACT
Bacteriophage lysin is characterized by high stability, wide bactericidal activity and efficacy, and safty. It is able to lyse bacteria specifically and is not susceptible to bacterial resistance. In the presence of phage, phage infecting bacteria and coding for endolysin then it lyse the bacteria, In the absence of the phage, holin assists the endolysin lysis the bacteria from external. In addition, the research progress on the treatment of Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus, Streptococcus pyogenes, and Gram-negative bacteria, such as Acinetobacter baumannii and Pseudomonas aeruginosa, was also discussed in this paper.
ABSTRACT
Objective To study the antibacterial mechanisms of ethyl acetate extract (B06e) from the fermentation liquid of an endophytic fungus Alternaria spp. Alternaria spp isolated from the medicinal plant Humata tyermanni. Methods Double dilution method was adopted to measure the minimum inhibitory concentration (MIC) of B06e against Escherchia coli. Then, the changes of electric conductivity of bacterial culture, nucleic acid and protein concentration before and after treated by B06e were analysed, respectively. Besides, flow cytometry, scanning electron microscopy, gel retardation experiments, circular dichroism spectrum and Real-time quantitative PCR were introduced to study the antimicrobial mechanisms of B06e against E. coli. Results The results showed that MIC value of B06e against E. coli was 25 μg/mL. The electric conductivity of 3 × MIC treatment group was 1.01 times the value of the control group. The β-galactosidase activity of 3 × MIC treatment group was 11.6 times more than the value of the control group. Flow cytometry analysis showed that PI positive cells ratio of 3 × MIC treatment group was 286.5 times the value of the control group. Scanning electron microscopy showed that cell surface becomes rough after the treatment of B06e, a large number of cell membrane collapse. These results suggested that B06e can increase the permeability of cell membrane, destroy the integrity of cell membrane. The results of gel retardation experiments and circular dichroism spectrum applied that B06e can be inserted into DNA structure at particular position, however, can not cause DNA degradation. Real-time quantitative PCR results showed that the expressions of recA and recN genes were both up-regulated with the values of 2.9 and 3.7 times the value of the control group, respectively. This result suggested that B06e can destroy the DNA structure, which force E. coli to initiate SOS repair. Conclusion B06e can kill E. coli cell by destroying the cell membrane and damaging DNA structure.
ABSTRACT
Aims@#This study was conducted to observe the stability of Spondias pinnata leaf (SPL) extract antibacterial at different pH, salt concentration and temperature, to examine its antibacterial effectivity on minced fish, and to determine its fraction’s antibacterial mechanism.@*Methodology and results@#The tested SPL ethanolic extract, n-hexane, chloroform, ethyl acetate and water fractions’ antibacterial activity against Bacillus cereus and Vibrio parahaemolitycus. Its stability against pH, salt, and thermal variation was studied, as well as the mechanism and application in fish. Ethyl acetate fraction and water fraction showed the highest activity against B. cereus (MIC 0.62 mg/mL). Protein profile analysis using gel electrophoresis showed that B. cereus cells exposed with SPL ethyl acetate fraction and water fraction showed thinner protein bands as compared to control. Severe damage of the cells treated with 3 MIC was also observed under SEM. Antibacterial activity of SPL ethanolic against Bacillus cereus and Vibrio parahaemolitycus were stable against heat treatment (80–121 °C for 15 min) and NaCl treatment (0–10% w/v), whereas the inhibition zone respectively at pH 4 (10.31±0.25 and 8.09±0.97 mm) was higher than pH 7 (8.45±0.52 and 6.66±1.84 mm). Application of SPL ethanolic extract in fish broth showed higher antibacterial activity than in fish flesh, which gave bactericidal effect at 3 MIC.@*Conclusion, significance and impact of study@#Ethanol extract can be developed as a natural preservative in fish
ABSTRACT
Objective:To study the antibacterial activity of sanguisorba tannin extract in vitro and its mechanism in the antibacterial effect on staphylococcus aureus. Methods:The antibacterial effect of sanguisorba tannin extract was studied by an Oxford-cup method and a tube double dilution method. With staphylococcus aureus as the tested bacteria, extracellular alkaline phosphatase (AKP), potassium ion, soluble protein and T-ATPase were determined. The changes in protein bands and the cell ultrastructure were respectively observed by SDS-PAGE and TEM to illustrate the antibacterial mechanism. Results:The results showed that sanguisorba tannin extract was effec-tive against the gram-positive bacteria, while the effect against the gram-negative bacteria was weak. After staphylococcus aureus was trea-ted with sanguisorba tannin extract, the contents of alkaline phosphatase (AKP), potassium ion, soluble protein, DNA, RNA and the other large molecules were increased obviously when compared with those in the control group. The concentrations of intracellular and ex-tracellular ATP were significant changed. DS-PAGE showed that staphylococcus aureus treated with sanguisorba tannin extract had no pro-tein band formation. TEM showed that the cell integrity was damaged. Conclusion:Sanguisorba tannin extract shows strong antibacterial activity, which can change the cell membrane permeability and damage the cell integrity.
ABSTRACT
Objective To study the antibacterial effect and mechanism of Resveratrol(RES)on Staphylococcus aureus stand-ard strains (ATCC 25923).Methods Using the microdilution protocol,to obtain minimal inhibitory concentrations(MIC)of RES on Staphylococcusaureus standard strains.Transmission electron microscope (TEM)and scanning electron microscope (SEM)were tested to obtain the effect of Staphylococcusaureus on Ultrastructure.Results The MIC of RES to Staphylo-coccusaureus standard strains ATCC 25923 were 0.256 mg/ml.Compared with control group,transmission electron and scanning electron microscope observation showed that after the act of RES on S.au standard strains,the cell morphology of S.au standard strains changed serious deformation,cells in all shapes and size,cell boundary roughness,cell wall defected and ruptured,and osteoporosis of edgeo,looseness of its structure,the nuclear membrane rupture,local showed vacuolar characteristics.Cell ultrastructure was obvious damaged and inhibition.Conclusion Rseveratrol had obvious inhibition and destruction to the standard strains of staphylococcus aureus,and the inhibition mechanism may be related to the destruction of cell membrane permeability.
ABSTRACT
Infection diseases induced by bacteria continue to be one of the greatest health problems worldwide. In this framework, nanotechnology-based solutions, and in particular silver nanoparticles ( AgNPs) , have recently emerged as promising candidates in the market as new antibacterial agents because of the enhanced broad-range antibacterial/antiviral properties and low cost.Here we analyze the experimental conclusions on the bactericidal effects of AgNPs, and discuss the safety issues.
ABSTRACT
OBJECTIVE: To study the antimicrobial activity and antibacterial mechanisms of cryptotanshinone against SA, MRSA and ESBLS-SA. METHODS: MIC value was determined by disc diffusion method. IC50 value was determined by liquid culture. The antibacterial mechanisms of cryptotanshinone were investigated by determining the changes in electric conductivity, concentration of AKP, protein content, and the changes of protein electrophoretic bands in SDS-PAGE. RESULTS: The antibacterial rings, MIC and IC50 values showed that the antimicrobial activity against SA was better than that against MRSA and ESBLs-SA. Treated with cryptotanshinone, the electric conductivity, concentration of AKP, and protein content were increased, and protein bands in SDS-PAGE were changed obviously. CONCLUSION: Cryptotanshinone significantly inhibits SA, MRSA and ESBLs-SA and can damage the structures of cell wall and cell membrane, which results in the increase of permeability of cell membrane and release of cell components. Cryptotanshinone can influence the synthesis of bacteria protein, destroy the protein or reject the anabolism or expression of the protein, and finally leads to the loss of normal physiological function of bacterium.
ABSTRACT
Objective: To investigate the interaction between ciprofloxacin (CIP) and ferric-ion binding protein (FBP) from pathogenic bacteria, so as to determine whether FBP is the target of CIP. Methods: Reactions between ciprofloxacin and FBP from N. gonorrhoeae, which was expressed in E. coli, were monitored by UV-visible and NMR spectroscopy. Results: Fe3+ was removed from holo-FBP by CIP in 10 mmol/L Tris-Cl buffer, pH 7.40, at 298 K, and half of the loaded Fe3+ was taken off when 50 molar equivalence of CIP was present. Conclusion: CIP can remove Fe3+ from holo-FBP, indicating that CIP can interfere with the Fe3+ capture of the bacteria and influence the growth and virulence of the bacteria.
ABSTRACT
The antibacterial property of silver nanoparticles has resulted in their widespread application in many fields,so the chance of silver nanoparticles exposure for human increased greatly.Thus,there is urgent need to assess the safety of such particle.So far,most toxicological studies of silver nanoparticles mainly focus on the cytotoxicity using different examination endpoint such as morphology,mitochondrial function,cell proliferation,enzyme activity,and so on.In addition,the in vitro studies on the toxicity of silver nanopoarticles are also reported,few of the study on molecule mechanism of toxicity was reported.This review provided a summary of antibacterial mechanism of silver nanoparticles and the current research situation of the safety.The future research direction of toxicological study of silver nanoparticles is also prospected based on the current knowledge.
ABSTRACT
Cecropin is a kind of heat-durable and broad-spectrum antibacterial polypeptides which has strong effect against bacteria,fungi,virus and some pathogenic microorganisms.Today Cecropin has been widely applied into plant genetic engineering,antiviral study,and inhibiting tumor cell proliferation.Its Structure-function relationship,antibacterial mechanism,and the application on transgenic plants for bacterium resistance was reviewed.Expression of Cecropin in plants has a great application potential in bacterium resistance.Deep analyses and research of molecular structure and action mechanism can promote the transgenic plants antibacterial research.