RESULTS: A thermostable organic solvent-tolerant protease producer had been identified as Bacillus subtilis strain Rand, based on the 16S rRNA analysis conducted, as well as the morphological characteristics and biochemical properties. The production of the thermostable organic solvent-tolerant protease was optimized by varying various physical culture conditions. Inoculation with 5.0% (v/v) of (AB600 = 0.5) inoculum size, in a culture medium (pH 7.0) and incubated for 24 h at 37 degrees C with 200 rpm shaking, was the best culture condition which resulted in the maximum growth and production of protease (444.7 U/ml; 4042.4 U/mg). The Rand protease was not only stable in the presence of organic solvents, but it also exhibited a higher activity than in the absence of organic solvent, except for pyridine which inhibited the protease activity. The enzyme retained 100, 99 and 80% of its initial activity, after the heat treatment for 30 min at 50, 55, and 60 degrees C, respectively.
CONCLUSION: Strain Rand has been found to be able to secrete extra-cellular thermostable organic solvent-tolerant protease into the culture medium. The protease exhibited a remarkable stability towards temperature and organic solvent. This unique property makes it attractive and useful to be used in industrial applications.
RESULTS: Prediction in two and three state classification systems with several thresholds are provided. Our prediction method achieved the accuracy level upto 90% for training and 88% for test data sets. Three state prediction results provide a maximum 65% accuracy for training and 63% for the test data. Applicability of neural networks for ASA prediction has been confirmed with a larger data set and wider range of state thresholds. Salient differences between a linear and exponential network for ASA prediction have been analysed.
AVAILABILITY: Online predictions are freely available at: http://www.netasa.org. Linux ix86 binaries of the program written for this work may be obtained by email from the corresponding author.
Materials and Methods: The bark was extracted using different solvents, for example, dichloromethane, ethyl acetate, methanol, and aqueous for obtaining the organic fractions. These organic fractions were then evaluated for their cytotoxic and antimicrobial activity compared with the standard. Cefixime was used as the standard for antibacterial assay, whereas clotrimazole was used as the standard for antifungal activities. Bacterial strains used were Staphylococcus aureus and methicillin-resistant S. aureus (MRSA), whereas for antifungal activities Candida albicans, Candida parapsilosis, and Candida krusei strains were used.
Results: The organic fractions obtained were evaluated for their cytotoxic and antimicrobial activities. In cytotoxic assay (Brine shrimp lethality assay), dichloromethane fraction was the most potent with LD50 of 47.63, whereas aqueous, methanol, and ethyl acetate fractions showed LD50 of 121.74, 422.2, and 201.96, respectively. Similarly, for antibacterial assay, dichloromethane fraction showed 32.2mm zone of inhibition against MRSA in comparison with standard cefixime (zone of inhibition, 30.5mm). A minimal zone of inhibition with crude saponins (13.1 and 12.2mm) was observed against C. albicans in comparison to standard (cefixime) with a zone of inhibition of 28.5mm. No prominent results were observed against C. parapsilosis and C. krusei strains.
Conclusion: The study was based on the plant from Indo-Pak origin, and it has shown some prominent cytotoxic and antibacterial activities. Although the results of this study have provided a basic idea about the efficacy of plant extract, still more explanatory and high-scale studies can be beneficial for elaborating the cytotoxic and antimicrobial activities of this plant.