Synthesis, Preparation and Antimicrobial Effects of Ag2S/PbSO4 Nanocomposites

The rapid and uncontrolled growth of microorganisms can lead to serious problems. With the development of nanotechnology over the last decade, golden opportunities have been created to discover the antibacterial effects of metallic nanoparticles. Metallic nanoparticles have an antibacterial effect, in addition to the inhibition effect of the particle, due to its small size, large surface area and large outer surface area. Scientists believe that nanoparticles can be used as appropriate alternative to used biochemicals. Introduction: In the past two decades, the field of nanotechnology has grown exponentially since its birth and has made an immense impact on physical, chemical, earth and biological sciences. There has been an immense extension of nanomaterial applications and uses as a result of basic and applied research from scientists all over the world. One such class of nanomaterials are metal oxide (MeO) and metalsulfides (MeS) nanoparticles (NPs), ranging in size from 1 to 100 nm, available in different shapes and sizes.  Methods and Results: In this research, nanoparticles were first made in 1, 5 and 1.5 mg/l concentrations, then we study antimicrobial properties of nanoparticles by MIC methods and several gram-negative bacteria were examined for several nanostructures. 0.0064 g nanoparticles solved to prepare 100 cc of the medium, weigh the hinton broth 2.1 grams, and in another stock 7.6 g hinton agar in 200 cc water, Then we make microbial leachate from the tested microorganisms and compare with the half McFarland their turbidity, to the extent that they are half McFarland. Then, with a micropipette of 2.5 microns from the lagoon, remove the bacteria on the plates, and finally place the plates in the incubator for 24 hours, and the next day the results are read. Conclusions: After making nanoparticles and investigating nanostructures on bacterial strains, we found that 32µg/ml of nanoparticles prevents the growth of bacteria in the control

Studies on bioemulsifier production by Bacillus licheniformis PTCC 1595

Surfactants are amphipathic molecules which reduce surface and interfacial tensions and widely used in pharmaceutical, cosmetic, food and petroleum industries. Biosurfactants are the structurally diverse group of surface-active molecules synthesized by microorganisms. There are several advantages for biosurfactants in contrast with chemical surfactants, such as lower toxicity; higher biodegradability; better environmental compatibility; higher foaming; high selectivity and specific activity at extreme temperatures, pH, and the ability to be synthesized from renewable feed-stock. In the present study, the production of bioemulsifer by Bacillus licheniformis PTCC 1595 was studied. B. licheniformis was grown in the nutrient broth medium and bioemulsifer production was evaluated every 24 h by surface tension and emulsification index (E24). Then B. licheniformis PTCC 1595 was grown in nutrient broth with different conditions in order to get maximum production of bioemulsifer. The best culture medium was found to be nutrient broth medium supplemented with starch, Fe2+, Mn2+ and olive oil. After growing the bacteria, the microbial biomass was removed from the supernatant by acidic precipitation method. Its amphipathic structure was established by biochemical and spectroscopy methods and it was confirmed to be a lipopeptide structure

Identification of Luteolin in Henna (Lawsonia inermis) Oil, a Persion Medicine Product, by HPTLC and Evaluating Its Antimicrobial Effects

Background and objectives: Persian scholars such as Avicenna and Zakariya al-Razi have pointed out many uses for henna oil. The present study aimed to propose a method for standardization of this oil. Methods: The luteolin content has been evaluated quantitively by HPTLC method to standardize the henna oil. The oil sample was applied on silicagel plate and the bands were developed using CHCl3-MeOH (95:5). The plate was scanned at λ 254 nm. The minimum inhibitory concentration was determined through the broth macrodilution test to examine the antibacterial activity of the oil. Results: The retention factor of the sample zone of luteolin standard was 0.6±0.01. The concentration of luteolin in henna oil was 56.57±0.66 μg/mL. MICof Henna oil against Gardnerella vaginalis and Neisseria gonorrhoeae was 87 μg/mL and against Streptococcus was 870 μg/mL. Conclusion: According to the results of this study, henna oil contains the luteolin. Further studies are needed to identify other henna oil compounds and their effects. Gardnerella vaginalis, N. gonorrhoeae, Group B streptococcus are among the pathogenic agents of cervicitis. The application of henna oil for treatment of uterus diseases in Persian medicine can be justified given the antimicrobial effects of henna oil on these three species of bacteria.<br /

Screening Three Strains of Pseudomonas aeruginosa: Prediction of Biosurfactant-Producer Strain

Problem statement: The chemical surfactants have some disadvantages; especially, toxicity and no biodegradability. Approach: Biosurfactants were the structurally diverse group of surface-active molecules synthesize by micro-organisms. The microbial surfactants were interesting, because of the biodegradable and have many applications in industry, agriculture, medicine. Results: In the present study, the production of biosurfactant by three strains of Pseudomonas aeruginosa (PTCC 1074, 1310 and 1430) was investigated. The hemolytic and foam forming activity of different strains were studied and consequently, P. aeruginosa PTCC 1074 was selected as the suitable strain. P. aeruginosa PTCC 1074 was grown in the nutrient broth medium and biosurfactant production was evaluated every 24 h by emulsification index and surface tension for the best of production time. After that, in order to get maximum production of biosurfactant, the selected strain was grown with different additives in nutrient broth and the best culture medium was found. The biosurfactant was isolated from the supernatant and its amphipathic structure was confirmed by chemical methods. Conclusion: Biosurfactant produced by Pseudomonas aeruginosa PTCC 1074 would be considered as a suitable surfactant in industries due to its low toxicity

ANTIMICROBIAL ACTIVITY OF BACILLUS SP. STRAIN FAS1 ISOLATED FROM SOIL

During screening for antibiotic producing microorganisms from environmental soil samples, the supernatant of a bacterial isolate was found to have antibacterial and antifungal activity on the standard indicator species. The standard cylinder-plate method was used to determine the inhibitory effect of the crude supernatant of each isolate on 6 bacterial and 3 fungal standard strains by measuring the diameter of inhibition zone. The highest inhibition zone on Aspergillus niger belonged to culture broth of isolate FAS1 by 25 mm, and this isolate was the most efficient microorganism to inhibit standard bacterial and fungal species. Based on morphological and biochemical properties as well as 16S rDNA gene analysis, the selected isolate (isolate FAS1) belonged to Bacillus genus. Investigation on the ability of different culture media for antibiotic production led to select Luria-Bertani media for further studies. Treatment of the culture broth of the isolate FAS1 using typical protease didn’t decrease the antimicrobial activity of the supernatant. After extracting of culture broth of the selected isolate by ethyl acetate as an organic solvent, the inhibitory effect was mainly increased. More investigation was done by bioautography method where the ethyl acetate fraction of the broth culture was separated on TLC by chloroform:methanol, 60:40 as mobile phase and Rf were calculated for inhibition spots