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The aim of this study was to evaluate the antibacterial activity of the water extracts of three species of Salvia (S. perspolitana, S. palaestina, S. bracteata) on Staphylococcus aureus, Escherichia coli and Pseudomonas aeroginosa. The antibacterial activity of water extracts of the studied species on the bacterial strains was examined using well diffusion method and minimum inhibitory concentration (MIC). Results showed that only S. bracteata formed growth inhibitory zone (9 mm) on Staphylococcus aureus. The extracts of all three plants formed growth inhibitory zone on E.coli and P. aeroginosa. The extract of S. bracteata was more effective than that of the other species. Results for MIC also showed that the extracts of S. perspolitana had the lowest effect on St. aureus and its MIC was observed in a concentration of 1024 µg/ml. The extracts of this species had the inhibitory effect in a concentration of 256 µg/ml. The uppermost inhibitory effect was provided by the extract of S. bracteata, since the minimum inhibitory concentration of this species for S. aureus was equal to 64 µg/ml; and for the other two bacteria, it was equal to 128 µg/ml. The extracts of S. palaestina had the lowest effect on S. aureus and its MIC was observed in a concentration of 1024 µg/ml. The extracts of this species had an MIC equal to 512 µg/ml for the other two bacteria. It was concluded that S. bracreata could be considered a suitable species with anti-bacterial activities in future researches.
 
 
 

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Phenazine 1-corboxylic acid (PCA) is an antibiotic, which inhibits the growth of a vast number of micro-organisms. PCA has has been applied in fields such as pharmaceutical, agricultural, marine and chemical industries. In this study, the antibiotic properties of PCA (produced by pseudomonas aeruginosa MUT.3, which is kept at the Microbial Collection of Malek Ashtar University of Technology) was studied. The impacts of temperature and light conditions on the activity of PCA was investigated within a 230-day period. To investigate the rate of PCA destruction in the experiment, high performance liquid chromatography (HPLC) was utilized. Moreover, the antibacterial activity of PCA under various conditions was studied by minimum inhibitory (MIC) and minimum biocidal concentration (MBC) methods against E. coli DH5α. The results showed that PCA could be active up to 210 days in darkness (at 25^oC). Meanwhile, the antibacterial activity of PCA was reduced to 100 and 50 days by increasing the temperature to 35 and 45^oC, respectively. In addition, PCA could be active up to 120 and 10 days in visible and ultraviolet light condition, respectively. The MIC and MBC data were consistent with the HPLC results. Detailed data on the activity and stability of phenazine 1-corboxylic acid under various environmental conditions, as presented in this study, could be helpful in industries and healthcare services.
 
 

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The biosynthesis of nanoparticles (NPs) has been proposed due to its fast, clean, safe, and cost-effective production and being efficient alternative to conventional physicochemical methods. This study aimed to isolate and identify aquatic yeast strains for their potential to form Zinc oxide nanoparticles (ZnONPs). A yeast strain, NS02, with high tolerance against zinc ion (5.25 mM) was isolated using the enrichment technique and was selected as efficient candidate for the biosynthesis of ZnONPs under cell-free extract (CFE) strategy. The preliminary evaluation on the formation of ZnONPs was performed by visual observation and UV-visible absorption spectra of the biosynthesized ZnONPs. The morphology, size and elemental distribution of the nanoparticles were determined by Field emission scanning electron microscopy (FESEM) equipped with energy-dispersive X-ray (EDX). X-ray diffractometer (XRD) was used to identify the crystalline phase of the ZnONPs. Antibacterial activity of ZnONPs against pathogenic bacteria isolated from the clinical specimens was investigated using agar well diffusion method. The isolate NS02 was characterized based on their morphological properties and amplification the ITS-5.8S-ITS2 rDNA regions. The present study pioneered the capabilities of the native aquatic strain Rhodotorula pacifica for the extracellular synthesis of ZnONPs with CFE strategy. The biosynthesized ZnONPs had a growth inhibitory effect all tested clinical isolates due to their nanometric size and well-defined dispersity. This investigation is attempted to indicate the novel microbial sources of aquatic yeasts as biological plant in the synthesis of ZnONPs with antimicrobial activity under cell-free extract strategy.