Antimicrobial activity of bacillus sp. strain fas 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 FASi 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 FASi] belonged to Bacillus gems. 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 FAS[1] using typical protease did't decease 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 chloroformimethanol, 60:40 as mobile phase and R[f] were calculated for inhibition spots

Bioassay screening of the essential oil and various extracts from 4 spices medicinal plants

Four commonly used spices plants in Iran were evaluated for cytotoxicity effect using Brine Shrimp Lethality [BSL] assay. Essential oils and various extracts of Heracleum persicum, Nigella arvensis, Cinnamomum zeylanicum and Zingiber officinale were assessed by two methods of disk and solution of BSL. Data were processed in probit-analysis program to estimate LC50 values. All of the tested fractions have exhibited more cytotoxicity in the solution method. Essential oils of H. persicum and C. zeylanicum have shown the most cytotoxicity with LC50 values 0.007 and 0.03 microg/ml respectively. None of aqueous extracts showed significant cytotoxicity. The analysis of the essential oil of H. persicum showed the hexyl butyrate and octyl acetate as the main compounds. These results suggest some limitation for using of these spices in diet. Furthermore, these plants could be considered as a source of cytotoxic compounds which might be studied in more details