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.

Antibacterial activity of eight Iranian plant extracts against methicillin and cefixime restistant Staphylococcous aureus strains

Objective:To assess the antibacterial activity of eight Iranian plant extracts against Staphylococcus aureus(S.aureus) strains which were isolated from infected patients.Methods: The studied strains were isolated from urine,stool,blood and wound of infected patients and identified by biochemical tests.In further,the antibacterial activity of 8 ethanolic local plant extracts including Querqus brantii(Q.brantii),Ziziphus spina-christi(Z.spina-christi),Peganum harmala(P.harmala),Oliveira decumbens(O.decumbens),Galium tricornutum(G.tricornutum), Vitex pseudo negundo(Vi.pseudo negundo),Salvia officinalis(S.officinalis),Vaccaria pyramidata (V.pyramidata) were then evaluated using agar disc diffusion method.Results:A total of 9 isolates were isolated and identified as S.aureus.Antibacterial profile of the strains showed that the strains were resistant to methicillin and cefixime.The highest antibacterial activity against the studied strains were belong to Q.brantii,P.harmala,Z.spina-christi and O.decumbens vent extracts with 11-40 mm,15-28 mm,8-26 mm and 10-20 mm of diameters,respectively. Intermediate antibacterial activity was exhibited by G.tricornutum and Vi.pseudo negundo against some of the studied strains with 7-20 mm and 7-13 mm of diameters,respectively. Noteworthy,out of 9 studied strains;6 and 2 of them were resistant to the G.tricornutum and Vi. pseudo negundo extracts,respectively.The S.officinalis and Va.pyramidata,however,showed no antibacterial activity against the studied strains.Conclusions:The Q.brantii,P.harmala,Z. spina-christi and O.decumbens extracts were shown to possess strong antibacterial activity against methicillin and cefixime resistant S.aureus strains and can be considered as the promising natural antibiotics for treating the studied strains.

A survey on Hibiscus rosa-sinensis,Alcea rosea L.and Malva neglecta Wallr as antibacterial agents

Objective:To guide for selection of plants with antibacterial activity for further phytochemical works on the isolation and identification of the active compounds.Methods:Ethanolic extracts of 3 species from Malvaceae family were evaluated by agar disc diffusion method for antibacterial activity against some gram-positive and gram-negative bacteria(Pseudomonas aeruginosa,Listeria monocytogenes,Staphylococcus epidermidis.Staphylococcus aureus, Klebsiella pneumoniae.Salmonella typhi,Bacillus cereus.Bacillus anthracis,Escherichia coli and Streptococcus pyogenes).The extracts were obtained from aerial parts of Hibiscus rosa(H. rosa)-sinensis(leaf and flower),Alcea rosea(A.rosea) L.(leaf and flower) and Malva neglecta(M. neglecta) Wallr(flower).Results:These extracts had inhibitory effects at different concentrations (0.05,0.10,0.20 and 0.40 g/mL) against above mentioned bacteria.Escherichia coli was the most resistant strain.The highest inhibitory zone was showed by ethanolic extract of M.neglecta against Staphylococcus epidermidis(22 mm) and followed by ethanolic extract from flower of H.rosa against Staphylococcus epidermidis and Staphylococcus aureus(20 mm).The Minimum Inhibitory Concentration(MIC) and Minimum Bactericidal Concentration(MBC) values against Staphylococcus epidermidis were equal(M1C=MBC=5 mg/mL for M.neglecta extract and for H. rosa extract MIC=MBC=20 mg/mL).Conclusions:These findings suggest that these native plants have good antibacterial properties that can be used for infection control and treatment and could also be as new source for antibiotics discovery and infection treatment.

Antimicrobial properties of Teucrium polium against some clinical pathogens

Objective:To explore the antibacterial effect of the alcoholic extracts of aerial parts of Teucrium polium,native in Iran on some pathogenic bacteria.Methods:Antibacterial activity of ethanolic extract(50 to 400 mg/mL) and methanolic extract(400 and 600 mg/mL) was evaluated by disc diffusion method.Results:The ethanolic extract results showed that Bacillus anthracis was the most sensitive species,while Escherichia coli and Proteus mirabilis were more resistant than others.In the case of the methanolic extract,Bordetella bronchiseptica was the most sensitive and Proteus mirabilis and Arcanobacterium pyogenes were the most resistant species.The hydroalcoholic extract of Teucrium polium had a relatively satisfactory effect on Salmonella typhi. The minimal inhibitory concentration(MIC) of Staphylococcus aureus and Salmonella typhi was 40 mg/mL and Bordetella bronchiseptica and Bacillus anthracis was 10 mg/mL.The minimal bactericidal concentration(MBC) against Bacillus anthracis was 10 mg/mL while against other species were not found(】200 mg/mL).The methanolic extract had also synergistic effect with methicillin,vancomycin against Staphylococcus aureus and with novobiocin against Salmonella typhi.Conclusions:These results suggest that this plant contains relatively good antibacterial activity and it can be used as a source of antiseptic compounds for medicinal uses.

Isolation of an antibiotic producer Pseudomonas sp.from the Persian Gulf

Objective:To investigate the isolation of marine antibiotic-producing bacteria from the Persian Gulf,as an untapped source for searching new natural antibiotics.Methods:Initially water and sediment samples were collected from 18 study sites in the some northern areas of Persian Gulf.All of the bacterial isolates using Marine Agar 2216 were inoculated into Marine broth and incubated on a rotary shaker at 28℃for 2-7 days.Bioactivily of their ethyl acetate extract was assessed at 100 mg/mL concentration in disc diffusion method against 6 gram-positive and 5 gram-negative bacteria.Synthetic antibiotics were used as control.Results:Altogether,46 bacterial colonies were isolated.Only one isolate from a marine sediment sample collected at a depth of 10 m,identified as Pseudomonas aeruginosa PG-01,was exhibited the capability of antibiotic production.The obtained raw extract from intended bacterium was effective against all tested gram positive bacteria while gram negative bacteria were resistance.Methicillin resisitant Stapuylococcus aureus(MRSA),Streptococcus pyogenes(S.pyogenes).Staphylococcus epidermidis (S.epidermidis) and Bacillus cereus(B.cereus) were the most sensitive strains.All of tested pathogens were multidrug resistant.The antibacterial compound from this bacterium was active even at 120℃.The optimized temperature and time for antibacterial metabolite production were 37℃and 72 hrs,respectively.Conclusions:Considering the antibacterial effect of Pseudomonas aeruginosa PG-01 especially against MRSA,it can be regarded the intended bacterium as a valuable strain and can give hope for treatment of diseases caused by multidrug resistant bacteria.

In vitro assay for the anti-brucella activity of medicinal plants against tetracycline-resistant Brucella melitensis

Brucellosis, a zoonosis caused by four species of brucella, has a high morbidity. Brucella melitensis is the main causative agent of brucellosis in both human and small ruminants. As an alternative to conventional antibiotics, medicinal plants are valuable resources for new agents against antibiotic-resistant strains. The aim of this study was to investigate the usage of native plants for brucellosis treatment. For this purpose, the anti-brucella activities of ethanolic and methanolic extracts of Salvia sclarea, Oliveria decumbens, Ferulago angulata, Vitex pseudo-negundo, Teucrium polium, Plantago ovata, Cordia myxa, and Crocus sativus were assessed. The activity against a resistant Br. melitensis strain was determined by disc diffusion method at various concentrations from 50-400 mg/ml. Antibiotic discs were also used as a control. Among the evaluated herbs, six plant (Salvia sclarea, Oliveria decumbens, Ferulago angulata, Vitex pseudo-negundo, Teucrium polium, and Crocus sativus) showed anti-brucella activity. Oliveria de- cumbens was chosen as the most effective plant for further studies. A tested isolate exhibited resistance to tetracycline, nafcillin, oxacillin, methicillin, and colistin. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values for Oliveria decumbens against resistant Br. melitensis were the same (5 mg/ml), and for gentamicin they were both 2 mg/ml. Time-kill kinetics for a methanolic extract of Oliveria decumbens was 7 h whereas for an ethanolic extract it was 28 h. Also, Oliveria decumbens extracts showed a synergistic effect in combination with doxycycline and tetracycline. In general, the similar values of MIC and MBC for Oliveria decumbens suggest that these extracts could act as bactericidal agents against Br. melitensis. In addition to Oliveria decumbens, Crocus sativus and Salvia sclarea also had good anti-brucella activity and these should be considered for further study.