Sequence analysis of putative swrW gene required for surfactant serrawettin W1 production from Serratia marcescens

Serratia marcescens produces biosurfactant serrawettin, essential for its population migration behavior. Serrawettin W1 was revealed to be an antibiotic serratamolide that makes it significant for deoxyribonucleic acid (DNA) and protein sequence analysis. Four nucleotide and amino-acid sequences from local strains analyzed through bioinformatics showed high confidence prediction of serrawettin. Database comparison analysis resulted to high similarity of the nucleotide sequence to the swrW gene of 88 to 94%, the homologous protein sequence to the serrawettin W1 synthetase protein ranging from 85 to 89%, presence of condensation domain from the non-ribosomal peptide synthetase (NRPS) family that synthesize peptide antibiotics and strong relation to the predicted surfactin synthetase structure. Further protein analysis showed high identical multiple alignment having conserved regions and the predicted structure representation was identified as putative surfactin a synthetase c (srfa-c), a non-ribosomal peptide synthetase termination module with 100% confidence. These nucleotide and protein sequence analysis of the putative swrW gene provides vital information on the versatility of S. marcescens as a pathogen of diverse hosts and an impetus for further genetic manipulation for practical applications.Keywords: swrW gene, serrawettin W1, non-ribosomal peptide synthetase (NRPS

Chemical- and irradiation-induced mutants of indica rice IR64 for forward and reverse genetics

IR64, the most widely grown indica rice in South and Southeast Asia, possesses many positive agronomic characteristics (e.g., wide adaptability, high yield potential, tolerance to multiple diseases and pests, and good eating quality,) that make it an ideal genotype for identifying mutational changes in traits of agronomic importance. We have produced a large collection of chemical and irradiation-induced IR64 mutants with different genetic lesions that are amenable to both forward and reverse genetics. About 60,000 IR64 mutants have been generated by mutagenesis using chemicals (diepoxybutane and ethylmethanesulfonate) and irradiation (fast neutron and gamma ray). More than 38,000 independent lines have been advanced to M4 generation enabling evaluation of quantitative traits by replicated trials. Morphological variations at vegetative and reproductive stages, including plant architecture, growth habit, pigmentation and various physiological characters, are commonly observed in the four mutagenized populations. Conditional mutants such as gain or loss of resistance to blast, bacterial blight, and tungro disease have been identified at frequencies ranging from 0.01% to 0.1%. Results from pilot experiments indicate that the mutant collections are suitable for reverse genetics through PCR-detection of deletions and TILLING. Furthermore, deletions can be detected using oligomer chips suggesting a general technique to pinpoint deletions when genome-wide oligomer chips are broadly available. M4 mutant seeds are available for users for screening of altered response to multiple stresses. So far, more than 15,000 mutant lines have been distributed. To facilitate broad usage of the mutants, a mutant database has been constructed in the International Rice Information System (IRIS; http: //www.iris.irri.org) to document the phenotypes and gene function discovered by users

Properties of the Ethanolic Leaf Extract of Merremia Peltata (L.) Merr. and Rubus SPP

Rubus species have been cultivated and have been used traditionally for therapeutic purposes as an astringent, ophthalmic and restorative. In the Philippines, the leaves of this plant have been used as treatment for cough especially by the Higa-onon tribes in Rogongon, Iligan City. While Merremia peltata (L.) Merr. is a species of flowering vine in the morning glory family, Convolvulaceae and the leaves are used for stomach pains, skin sores and inflammation. This study was to determine the phytochemical and antibacterial properties of ethanolic and water leaf extracts of these two ethnomedicinal plants, Merremia peltata (L.) Merr. and Rubus spp. since not much has been known so far. The Kirby-Bauer disc diffusion method was used to test the antimicrobial activity of the two extracts at 5, 10, 15, 20 and 25 ug/ml concentrations. Four bacterial strains were used and were grown overnight at 37°C in the Mueller-Hinton Agar (MHA) plates with the treated discs. Results showed that both ethanolic and water extracts of Merremia peltata (L.) Merr. and Rubus spp. had inhibitory effect on Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. The ethanolic and water leaf extracts of both plants showed strong to moderate inhibitory activity against the test bacterial strains compared to positive controls. However, the inhibitory effect exhibited by ethanolic extract was significantly higher than that by water extract (p<0.05). Also, the inhibitory activity of both plant extracts on all test isolates showed no significant difference among concentrations. Phytochemical analysis revealed the presence of steroids and flavonoids in both plant samples. Alkaloids were found only in Merremia peltata (L.) Merr. while tannins were only found in Rubus spp. Thus, this may indicate that both plants have the potential bioactive substances for medicinal purposes as claimed by the Higaonon tribe