Magnetic polyacrylonitrile/ZIF-8/Fe_(3)O_(4) nanocomposite bead as an efficient iodine adsorbent and antibacterial agent

The efficient adsorption of radioactive iodine(^(129)I and^(131)I)as nuclear waste is of great importance.Polymer nanocomposites consist of metal-organic frameworks(MOFs)developing for various pollutions sorption and separation have attracted much attention.This study reports the fabrication of magnetic polyacrylonitrile(PAN)/zeolitic imidazolate frameworks(ZIF-8)nanocomposites,PAN/ZIF-8(x%)/Fe_(3)O_(4),x=30 and 50,as iodine capture adsorbents.The PAN/ZIF-8(x%)/Fe_(3)O_(4)nanocomposite beads were fabricated via the phase inversion method,and their potential for iodine capture and separation in solution and vapor was investigated through UV-vis and weighing methods,respectively.Also,antibacterial activity of the as-prepared beads was assessed against E.coil and S.aureus.The as-fabricated compounds were studied by various techniques such as Fourier-transform infrared,X-ray diffraction,scanning electron microscope,energy-dispersive X-ray spectroscopy mapping,transmission electron microscope,N_(2)adsorption isotherm,and vibrating sample magnetometer.The iodine capture results showed that the efficiency of nanocomposites is remarkably higher than the pure PAN beads.Additionally,the asprepared nanocomposite adsorbents displayed higher capture capacities for iodine vapor(1524-4345mg·g^(-1))than iodine solution(187-295 mg·g^(-1)).The as-obtained magnetic nanocomposites can be successfully separated from polluted media by simple filtration or an external magnet,regenerated through washing with ethanol,and reused.Fast capturing,high sorption capacity,rapid separation,and good reusability make the PAN/ZIF-8(x%)/Fe_(3)O_(4)nanocomposites highly effective adsorbents for the separation of iodine from wastewater.Additionally,PAN/ZIF-8(50%)/Fe_(3)O_(4)bead can be considered as a potential new antibacterial agent for water and wastewater treatment.

Dynamic Expressions of Liver Tissue Apoptosis-related Genes of Vibrio Vulnificus Sepsis Rats and the Effects of Antibacterial Agents

Dynamic changes in mRNA expressions of liver tissue apoptosis-promoting genes Fas and Bax and apoptosis-inhibiting gene Bcl-2 of vibrio vulnificus sepsis rats were detected and the effects of antibacterial agents were examined. The rat model with Vibrio vulnificus sepsis （VV group） was established and some of the Vibrio vulnificus sepsis rats were treated with antibacterial agents （AA group）. The mRNA expressions of Fas, Bax and Bcl-2 were measured by reverse transcription polymerase chain reaction （RT-PCR）. As compared with normal control group （NC group）, the ex- pressions of Fas and Bax mRNA in liver tissue at all different time points in VV group were increased significantly （P〈0.05）, and the highest levels of Fas and Bax mRNA expressions were 6 and 12 h after the infection, respectively. At the same time, the expression of Bcl-2 mRNA in liver tissue at all different time points in VV group were decreased significantly （P〈0.05）, and the lowest level of Bcl-2 mRNA expression appeared 2 h after the infection. The mRNA expressions of Bcl-2 in liver tissue 9 and 12 h after the infection in AA group were increased significantly （P〈0.05） compared with NC group, while the expressions of Fas and Bax mRNA were not significantly different from those of NC group. Compared with VV group, the expression of Fas mRNA in AA group was decreased （P〈0.05） and Bax rnRNA was decreased significantly 12 and 16 h after the infection （P〈0.05）, while the expressions of Bcl-2 mRNA were increased significantly 9, 12 and 16 h after the infection （P〈0.05）. It is concluded that the mRNA expressions of liver tissue apoptosis-promoting genes Fas and Bax were increased remarkably in vibrio vulnificus sepsis rats, whereas the expression of apoptosis-inhibiting gene Bcl-2 mRNA was decreased obviously in sepsis rats in early stage. The treatment with cefoperazone sodium and levofloxacin lactate could inhibit the expression of Fas mRNA and Bax mRNA and enhance the expression ofBcl-2 rnRNA at the same time.

Prediction Model of Antibacterial Activities for Inorganic Antibacterial Agents Based on Artificial Neural Networks

Quantitatively evaluation of antibacterial activities of inorganic antibacterial agents is an urgent problem to be solved. Using experimental data by an orthogonal design, a prediction model of the relation between conditions of preparing inorganic antibacterial agents and their antibacterial activities has been developed. This is accomplished by introducing BP artificial neural networks in the study of inorganic antibacterial agents. It provides a theoretical support for the development and research on inorganic antibacterial agents. Key words inorganic antibacterial agent - antibacterial activity - neural networks - nanometer material

The effect of antibacterial agents on the production of nitric oxide induced by lipopolysaccharide in mice

Some antibacterial agents have been shown to neutralize the biological properties of bacterial lipopolysaccharide (LPS). The aim of this study was to eluci- date the role of gentamicin, tobramycin, imipenem, tigecycline, and isoniazid in affecting the production of nitric oxide (NO) induced by LPS in mice. Groups of mice were injected intraperitoneally with LPS alone, antibacterial agent alone, or LPS in combination with an antibacterial agent. Serum NO levels were determined at 1, 3, 6 and 9 hours post-injection using the Griess reagent method. Thin layer chroma- tography was performed to determine if antibacterial agent—LPS interaction had occurred. All the antibacterial agents suppressed NO production. More- over, LPS-induced production of NO was suppressed by all the antibacterial agents, tobramycin and tigecycline being the most effective at 9 hours post-injection. Blocking of any of the stages leading to NO production by the antibacterial agents is suggested. Moreover, thin layer chromatograms obtained are suggestive of LPS-antibacterial agent interactions.

Efficient Synthesis of a New Class of <i>N</i>-Nucleosides of 4<i>H</i>-Thiochromeno[2,3-<i>d</i>]pyrimidine-10-Sulfone as Potential Anticancer and Antibacterial Agents

A highly practical and efficient preparation of 6-methy-4H-thiochromene and 7-methyl-thiochromene[2,3-d]pyrimidine derivatives was developed via a multi-component reaction of 3-methyl-thiophenol (1), aldehydes (2), and malononitrile (3). A series of pyrimidine nucleoside, thiochromene[2,3-d]pyrimidine and thiochromene[2,3-d]pyrimidine-10-sulfone was efficiently obtained. These hybrid compounds were evaluated as potential antibacterial and anticancer agents and showed encouraging biological activities. Some of these derivatives showed broad-spectrum antitumour activity against the nine tumour subpanels tested, and demonstrated significant activity in the in vitro antitumour screening expressed by MG-MID log10GI50 value of -4.55, -4.67 and -4.73 of compounds 9a, 9b and 9c, respectively.

The Synthesis of the Reactive Antibacterial Agents and Their Antibacterial Activities

A series of monochlorotriazine reactive antibacterial agents were synthesised by using 2,4,4’ - trichloro -2’ - hydroxydiphenyl ether as a starting material. The spectrum analyses (UV and MS) and elementary analy-ses were also carried out. These antibacterial agents can be used as the bacteria - resistance finishing agents of the cellulose fabrics. The treated fabrics possess excellent antibacterial activity and durable wash fastness. For ex-ample , the percentages of bacterial reduction of the fab-ric finished with reactive antibacterial agent 2RSDP are 98.5%, 98. 86% and 96.67% for Staphylococcus au-reus, Escherichia coli and Pseudomonas aeruginose re-spectively. After more than 100 times of washing at 60°C, the antibacterial activity still retains at a level of about 90% of the original. The relationships between the molecular structures of the reactive antibacterial finish-ing agents and their antibacterial activities are discussed.

Physicochemical Property Testing of a Novel Maize Seed Coating Agent and Its Antibacterial Mechanism Research

We used the no pollution natural polymer polysaccharide chitosan as the main raw material, which is supplemented by other additives, to prepare a high-efficiency environmental friendly maize seed coating agent. By detecting the seed quality, maize seedling indexes, which include root activity, chlorophyll content and malondialdehyde (MDA) content, and through the results we found that this seed coating agent could improve the photosynthetic capacity and enhance seedling resistance. Laboratory bacteriostasis test and study showed that the antibacterial rate of this seed coating agent has reached more than 88%. Meanwhile, we analyzed and studied the antimicrobial mechanism of the seed coating agent.

Honey:its medicinal property and antibacterial activity

Indeed,medicinal importance of honey has been documented in the world's oldest medical literatures,and since the ancient times,it has been known to possess antimicrobial property as well as wound-healing activity.The healing property of honey is due to the fact that it offers antibacterial activity,maintains a moist wound condition,and its high viscosity helps to provide a protective barrier to prevent infection.Its immunomodulatory property is relevant to wound repair too.The antimicrobial activity in most honeys is due to the enzymatic production of hydrogen peroxide.However,another kind of honey,called non-peroxide honey(viz.,manuka honey),displays significant antibacterial effects even when the hydrogen peroxide activity is blocked.Its mechanism may be related to the low pH level of honey and its high sugar content(high osmolality) that is enough to hinder the growth of microbes.The medical grade honeys have potent in vitro bactericidal activity against antibiotic-resistant bacteria causing several life-threatening infections to humans. But,there is a large variation in the antimicrobial activity of some natural honeys,which is due to spatial and temporal variation in sources of nectar.Thus,identification and characterization of the active principle(s) may provide valuable information on the quality and possible therapeutic potential of honeys(against several health disorders of humans),and hence we discussed the medicinal property of honeys with emphasis on their antibacterial activities.

Synthesis and Antibacterial Activity of 8-Substituted Phenyl-1-pyridin-3-yl-5H-bis[1,2,4]triazolo[3,4-b;4′,3′-d][1,3,4] thiadiazines

To find new structural leading compounds for the research of the multidrug resistant of antibacterial agents, five novel 8-substituted phenyl-1-pyridin-3-yl-5H-bis[1, 2, 4] triazolo[3, 4-b; 4′, 3′-d] thiadiazines were prepared from the corresponding intermediates of 3-(5-substituted phenyl[1,3,4]oxadiazol-2-ylmethylsulfanyl)-5-pyridin-3-yl-[1,2,4]triazol-4-ylamines via intramole- cular cyclization and the antibacterial activity in vitro against Gram-postive (G+) and Gram negative (G-) bacteria was primarily evaluated.

Synthesis and Antibacterial Activity of New Tetracyclic Triazolo-thiadiazino Fluoroquinolones

A series of novel 9-fluoro-10-(4-methylpiperazin-1-yl)-3-substituted-8-oxo-8H-[1,2,4] triazolo[3,4-b]thiadiazino[6,5,4-ij]quinoline-7-carboxylic acids was prepared by a facile synthetic method and the in vitro antibacterial activity against Gram-postive (G+) and Gram negative (G-) bacteria was primarily evaluated.

Review of copper and copper alloys as immune and antibacterial element

This review discussed the relationship among copper,human,and bacteria.Copper plays an important role in human immunity.Copper can boost human immune defense reactions at recommended intake level.The content mainly focused on copper antibacterial activity and copper antibacterial mechanisms.Conclusions stated that copper antibacterial activity is affected by copper homeostasis mechanisms in bacteria,adhesion,humidity,strain specificity,and manufacturing methods of antibacterial agents.For the preparation of particle antibacterial agents and surface antibacterial agents,this review discussed several manufacturing methods,such as sol−gel,cold spray,and biosynthesis belonging to chemical synthesis,physical synthesis,and biological synthesis,respectively.Sol−gel method contributes to the preparation of particle agents and surface agents.Cold spray technique is utilized in synthesis of surface copper agent.Biosynthesis is a novel technology which can be applied in nanoparticle agent preparation.

Determination of Malaysian Herbs and Spices as Biopreservative Agents in Food Products

Preservatives are usually added to food products to ensure longer shelf life and prevent decomposition process and microbial growth. However, synthetic food preservatives can also give negative side effect to health and are harmful to human and animal physiology. Based on the potential of herbs and spices as antimicrobial agent, the purpose of this study is to identify antibacterial activity from extracts of some local herbs and spices: Phaeomeria speciosa (P. speciosa), Aquilaria subintegra (A. subintegra), Polygonum minus (P. minus), Syzygium aromaticum (S. aromaticum), Cinnamomum verum (C. verum) and Piper nigrum (P. nigrum) against food bacteria using disc diffusion method. Results revealed that dichloromethane extracts of C. verum, hexane extracts of S. aromaticum and P. minus showed the most active antibacterial against tested bacteria. The Minimal Inhibitory Concentrations (MIC) ranged from 25 to 75 mg/ml for dichloromethane extract of C. verum, hexane extract of S. aromaticum and P. minus. Therefore further research should be pursued to identify the chemical structure of antibacterial agents from the active extracts as an alternative source of natural preservatives.

Evaluation in vitro of an Experimental Antibacterial Silk Suture

Because of good clinical performance and low cost,silk braided surgical suture becomes one of excellent and widely used sutures. But as a kind of natural protein fiber,silk easily trends to microbial infection. Beyond that,braided structure may increase the risk of hide of bacteria. Hence,the project of this study is to develop a novel antibacterial silk braided suture. Silk braided sutures were treated with antimicrobial solution which added antimicrobial agent4-quinolones into 5% polycaprolactone( PCL) solution. Then sutures were tested for in vitro efficacy against Staphylococcus aureus(S. aureus) and Escherichia coli(E. coli) by a zone of inhibition assay,and sustained efficacy assay,release of antibacterial agent,SEM photographs against S. aureus. Treated sutures exhibited distinct zones of inhibition against S. aureus and E. coli. They also kept antimicrobial property against S. aureus for 7 d,which were almost equal with coated VICRYL*Plus sutures. The highest release concentration of treated suture was 1. 53 mg /L,which was lower than Cmaxof 4-quinolones,proved the safety of antibacterial silk suture. SEM photographs gave both the change of the surface and different bacteria growth situations on the surface before and after treating.

Anti-hemolytic, antibacterial and anti-cancer activities of methanolic extracts from leaves and stems of Polygonum odoratum

Objective: To investigate anti-hemolytic, antibacterial and anti-cancer activities of leaf and stem extracts from Polygonum odoratum. Methods: Leaves and stems of Polygonum odoratum were extracted using methanol and their anti-hemolytic activity was assessed using 2, 2′-Azobis(2-methylpropionamidine) dihydrochloride which is known to generate free radical damage on cell membranes of red blood cells. This damage, represented by hemolysis, was measured using spectrophotometry. Antibacterial activity was tested by using a broth microdilution method to find minimal inhibitory concentrations against eight bacterial strains. Anti-cancer activity of the extracts was evaluated against a human promyelocytic leukemic cell line(HL-60) by using MTT assay for cell viability and flow cytometry for apoptosis induction and cell cycle analysis. Results: Both leaf and stem extracts have anti-hemolytic activity. The results showed a significantly increased percentage of inhibition in a concentration-dependent manner. Interestingly, the leaf extract showed anti-hemolytic activity to a greater extent than the stem extract. Antibacterial activity of the extracts, as indicated by their minimal inhibitory concentration, using 12.5, 50, 25, 25 μg/mL, was measured against Staphylococcus epidermidis, Enterococcus faecium, Enterococcus faecalis and Staphylococcus aureus. The leaf extracts also exhibited anti-cancer activity, demonstrated by significantly decreased cell viability of human promyelocytic cells(HL-60), with an IC_(50) of(350.00±1.85) μg/mL for 48 h and(38.00±0.92) μg/mL for 72 h. Additionally, HL-60 became apoptotic and accumulated in G_1-phase after 48 hours of treatment. Conclusions: The extracts of Polygonum odoratum exhibit potential antihemolytic activity. They also have antibacterial activity by inhibiting growth of Gram-positive bacteria. The leaf extract shows anti-cancer activity against HL-60 to a greater extent than the stem extract, causing decreased viability, increased G_1-phase accumulation and apoptosis induction.

PREPARATION AND THEIR ANTIBACTERIAL ACTIVITY OF ACTIVATED CARBON FIBER CONTAINING SILVER

Several kinds of activated carbon fiber（ACF）, Granule Activated carbon（AC） containing silver ion or fine silver particle(Ag-ACF/AC) have been prepared by soaking ACF or AC in the salt solution of silver. Ag, AgCl and AgI compounds have been loaded onto the fibers. The structure of the fibers was measured by scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). The Ag content in the fiber was obtained by an Atomic absorption spectroscopy (AAS). The Ag+ content in water after the antibacterial test was measured by an Inductively Coupled Plasma (ICP) emission spectroscopy. Antibacterial test was carried out against Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus). The results show that Ag-ACF/AC have strong antibacterial activity against E.coli and S.aureus. After dealt with ACF/AC loading Ag, AgCl, AgI, no E.coli and S.aureus alive in solution can be detected. The analysis of Ag content in water after antibacterial test showed that the content of Ag meet the quality requirement of the National Potable Water Standard. It is indicated that ACF/AC-Ag in this experiment would be a safe antibacterial agent .

Antibacterial Dental Resin Composites: A Narrative Review

Lack of antibacterial properties in resin-based composites (RBCs) is one of the flaws that cause the failure of filling clinically. Several agents have been incorporated to endow RBCs with antibacterial properties. In this review, we summarize the recent antibacterial agents between 2015 and 2020 using keywords of antibacterial or antimicrobial dental resin composites by PubMed databases. The most effective strategies are concerned with polymerizable monomers (50%), followed by filler particles (39%) and leachable agents (11%). A recent modification of the antibacterial agent is either by combining two agents from the same category or mixing agents from different categories in one. More than two methods were used in one study to assess antibacterial efficacy. The most common method was biofilm colony-forming units (CFUs) counting method (40%), followed by live/dead bacteria staining assay of biofilms (25%), metabolic activity assay of biofilms using MTT assay (16%), lactic acid production assay of biofilms (8%), agar diffusion test (8%), and other methods (3%) such as minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC).

Synthesis and Antibacterial Performance of Quaternary Phosphonium Salts with Reactive Hydroxyl Group

Quaternary phosphonium salts （QPS） with reactive groups used as antibacterial agents are promising which could be covalently linked to inert polymer surfaces by in situ polymerization. In this work, two kinds of quaternary phosphonium salts with hydroxyl groups were synthesized successfully. Characterization of these two quaternary phosphonium salts was performed by the Fourier transform infrared spectroscopy （FT-IR） and nuclear magnetic resonance （NMR） spectrometry. The thermal stability and antibacterial activity of antibacterial agents were also investigated by using thermo-gravimetric analysis, differential scanning calorimetry （TG-DSC） and agar diffusion method. The test results showed that these two QPS exhibited good thermal stability and excellent antibacterial activity against both bacteria： Staphylococcus aureus and Escherichia coll.

Derivatives of Thiohydrazides as Effective Antibacterial Remedies for Chlamydial Infection Treatment at Chronic Stages of Infections

Hydrazones of poorly studied fluorine-containing oxamic acid thiohydrazides were synthesized by the reaction with salicylaldehydes. Tests showed that the newly synthesized compounds were effective low-toxic inhibitors of type III secretion system in Chlamydia trachomatis.

From Environmental Toxicants to Antibacterial Agents:BPA Analogues Selectively Inhibit the Growth of Gram-Positive Bacteria by Disturbing Biosynthesis of the Cell Wall

Remarkable antibacterial activity of BPA analogues especially for tetrabromobi-sphenol A against Staphylococcus aureus 25923(Sa25923)and methicillin-resistant Staphylococcus aureus(MRSA)has been reported in our previous studies.However,the toxic effects of the compounds as environmental contaminants on the endocrine system limited their applications in the field of medicine and health.Given the abuse of antibiotics has led to the emergence of multiple super-resistant bacteria,we considered that structural modifications based on the BPA structure will be available for molecular designing of potential antimicrobial agents without drug resistance.In this study,to further improve the antibacterial activity and reduce the biological toxicity,we performed the computational models to evaluate the binding affinities of BPA analogues to the potential target DltA protein in the biosynthesis of cell wall.A series of synthesized achiral analogues ofα,α,α′-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene(α,α,α′-TEIB)exhibited low minimum inhibitory concentration against Sa25923 and MRSA(2 or 1μg mL−1).Especially,the analogue A4 did not induce the drug-resistant mutants for all tested Gram-positive bacterial strains and exhibited relatively lower cytotoxicity in HepG2 cells.The developed classification model based on the light gradient boosting algorithm showed the superior performances on the internal robustness and generalization ability for the ligand-based virtual screening of bisphenol and polyphenol antimicrobial substances.Collectively,our findings suggest that the molecular structure ofα,α,α′-TEIB is promising as a scaffold,which is expected to achieve a breakthrough in the development of antibiotics which can prevent the invasion of MRSA and other super bacteria.