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Saline soils are widely spread in Iran. These intact soils are a great source for the isolation of new bacteria with highly functional metabolites in biotechnology. Actinomycete strains were isolated on starch casein agar and ISP2 with different concentrations of sodium chloride (0, 5 and 10%) from treated soil samples. Pure colonies were cultured on a casein glycerol medium. After complete growth, the plates were covered with a thin layer of Muller Hinton Agar (1%) containing methicillin-resistant Staphylococcus aureus (MRSA). Active metabolites of selected strains were extracted and their antibacterial activities analyzed by agar well diffusion method. 38% of isolates produced antibiotics against the pathogen. The metabolites produced by act-2 and act-5 isolates, which had a more effective inhibition zone against MRSA, were extracted and anti MRSA activity of act-5 extract was shown. The antimicrobial activity of act-5 against other bacteria was also investigated and the bacterium was identified. In this study halophilic actinomycetes producing bioactive compounds were isolated from the saline soils of Qom and the anti-MRSA potential of their metabolites was investigated for the first time. The results of this study show the potential of saline soil actinomycetes for the production of useful metabolites.


 

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Centella asiatica, is well known to be a valuable medicinal plant for producing valuable compounds such as asiaticoside, asiatic acid, madcasoside and madcasic acid. The plant is believed to improve memory, lower blood pressure, be a strong antioxidant and anticancer. Therefore, it is important to optimize tissue culture methods in order to facilitate the extraction of medicinal compounds, gene transfer as well as improvement of medicinal properties of the plant. Calli prepared from various medicinal plants can be used to increase the amount of medicinal compounds in the cell suspension culture and gene transfer. The aim of this study was to investigate the effect of different concentrations of two hormones, BAP and NAA, on leaf explant for callus initiation, as one of the important sources of secondary metabolites production. For this purpose, leaf explants were treated with 6 different concentrations of BAP (0, 0.5, 1, 1.5, 2.5, 3.5 mg/L) and 5 different concentrations of NAA (0, 0.25, 0.5, 1, 2 mg/L). The results of this study showed that the best callus was obtained by the combination 1.5 mg/L of BAP and 0.5 mg/L of NAA, resulting in the leaf explants with callus induction of 100%, fresh weight of 1.457 gr and callus diameter of 1.459 cm. The results showed that two hormones of BAP and NAA have synergistic effects on the increase of the quality and quantity of the produced calli.

 

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The present study aimed to investigate the effect of some bio-elicitors and silver nitrate on the content of secondary metabolites in calli derived from leaf explants of silybum marianum. In this research, the best callus was achieved on MS medium containing KIN, thus this medium was chosen for further experiment. In the second experiment, leaf explants were cultured in a selected hormone-regulated medium. After 8 weeks of callus growth, bio elicitors including yeast Yarrowia lipolytica, fungus Aspergillus niger, and bacterium Pseudomonas putida in combination with silver nitrate as a non-living elicitor were added to the leaf-derived calli. Ten days after treatment, the phenolic compound content, antioxidant capacity, silymarin content, and PAL enzyme activity in the calli were measured. The results indicate that the simultaneous application of Yarrowia yeast and silver nitrate led to an improvement in the content of phenolic derivatives, silymarin, and PAL enzyme activity, and this was significant compared to other elicitors both with silver nitrate and without it. The researchers of this experiment suggest that the combined use of bio-elicitors especially Yarrowia lipolytica yeast, and silver nitrateinduces higher synthesis of medicinal metabolites in calli derived from leaf explants.