Molecular Identification of Streptomyces producing antibiotics and their antimicrobial activities

Five strains of Streptomyces, namely S, N, W, E and C (designations should be mentioned in detail here) isolated from the rhizosphere soil cultivated with palm Alajua (date, pressed dates), AlMedina city, Saudi Arabia, were induced to produce antibiotics. Antimicrobial activities were determined on solid medium supplemented with starch. The detection was based on the formation of transparent zones around colonies. The results indicated that isolates had antibacterial activities against Staphylococcus aureus, Bacillus cereus, B. subtilis, Pseudomonas aeruginosa and also showed antifungal activity against Candida albicans and Aspergillus niger. DNA extracted from five isolates was used as template for 16s rDNA gene amplification. The expected PCR size was 1.5 kbp;1.6 kbp; 1.25 kbp; 1.25kbp and 1.0 k bp for S, N, W, E and C isolates respectively using universal 16s rDNA gene primers using direct PCR. The isolates varied morphologically on the basis of spore color, aerial and substrate mycelium formation, and production of diffusible pigment. Isolates were tested under a microscope by using slide culture technique. The results indicate that the soil of this region is source of Streptomyces having antibacterial and antifungal activity and thus better utilization of these microorganisms as biological control agents

Impact of Moringa aqueous extract on pathogenic bacteria and fungi in vitro

Moringa peregrine have many benefits. In this study aqueous extract of Moringa plant inhibited the activity of these bacteria which include Bacillus cereus; Staphylococcus aureus; Pseudomonas aeruginosa, Klebsiella pneumonia, Escherichia coli; Enterococcus cloacae; Salmonella typhi and; Proteus vulgaris. Moringa extracts has shown an impact on the growth of bacteria on the Blood with inhibition zone variable (23.5 ± 0.45 to 12.5 ± 0.50 mm) according to the type of bacteria. The mean growth inhibition percentages were 85.9 ± 0.42 to 65.3 ± 0.34 nm against all tested bacteria. As regards to fungi, high potency extract displayed zones of inhibition of ⩾10 mm, moderate potent extracts gave zones of inhibition between <10 and 9 mm. The results indicated that, Moringa aqueous extract played variable antifungal activity ranged from high (18 ± 0.54 mm), moderate (13.2 ± 0.58 mm) and low (6.6 ± 0.47 mm). The inhibition zones diameter in millimeters against A. niger, A. flavus, P. italicum, F. oxysporum, R. stolonifer, Alternaria sp., C. albicans, C. parapsilosis were 15.2 ± 0.52, 12.4 ± 0.55, 10.5 ± 0.26, 9.4 ± 0.71, 13.2 ± 0.58, 6.6 ± 0.47, 12 ± 0.44 and 18 ± 0.54, respectively. On the other hand, the mean inhibition of growth (as percentages) were 75.2 ± 0.55, 59.4 ± 0.75, 58.2 ± 0.63, 46.5 ± 0.63, 62.5 ± 0.77, 24.5 ± 0.65, 20.3 ± 0.75 and 80.00 ± 0.70% respectively. Thus, the aqueous extract of Moringa leaves showed antimicrobial activity against tested bacteria, fungi and yeasts at different concentrations