Production, Purification and Characterization of a Novel Bacteriocin Produced by Bacillus subtilis VS Isolated from Mango (Mangifera indica L)

Abstract Bacteriocin has been identified as an excellent alternative to chemical preservatives due to its astonishing antimicrobial activity against food spoiling and food-borne pathogens. So there is a need to identify the newer and potent sources of bacteriocin producers. This study aims the isolation of potent bacteriocin producing microorganism from fresh fruits and vegetables, its production, purification, and characterization. Firstly, 43 isolates were analysed for its antimicrobial potential, out of which7 were found to inhibit the growth of various pathogens. Considering the results of antimicrobial activity; the microorganism isolated from mango was regarded as the most potent one; which was identified as Bacillus subtilis VS.70% ammonium sulphate precipitated and dialysed bacteriocin was purified using DEAE cellulose and sephadex G75 chromatography. Bacteriocin was purified by 24.64 fold with 8.65% recovery and its molecular weight was found to be 31.2kDa. The Purified bacteriocin was found to be stable at broad pH and temperature. It was found to be degraded by various proteases studied confirming its proteinaceous nature. Considering all these attributes; the purified bacteriocin isolated from Bacillus subtilis VS can be exploited by various food industries.

An analysis of vascular system in the compound tendrilled afila leaf in Pisum sativum.

Recent work on the venation patterning and morphogenesis of leaf/leaflet has posed the question how different are these in tendrils, which are another type of vegetative lateral organ. Here, the venation patterns of leaflets, stipules and tendrils were compared in the model species, P. sativum. Unlike reticulated venation in leaflets and stipules, venation in tendrils comprised of one or more primary veins. A few secondaries were attached to a primary vein, mostly distally. Bilaterally symmetrical secondary veins were rare. The primary veins in tendrils were daughter strands from dichotomously divided mother veins in rachis, connected finally to vascular strands in stem. A tendril received primary vein from one or more mother strands. Some mother strands contributed primary veins to proximal, distal and terminal domain tendrils of af leaf. The tendrils shared the multi-primary vein character with stipules. Vein redundancy provided a mechanism for survival of tendril/leaf against injury to some of the veins/mother veins. The presence of aborted primary veins that did not reach apex, rows of cambium cells attached to primary vein(s) at apex, the pattern of attachment of primary veins to mother veins and cessation of vein growth in apical direction in aborted tendrils of af lld genotype indicated that the growth of primary veins and tendril was acropetal. Loss-of-function of AF extended the repression of TL and MFP genes on leaflet development from distal and apical domains to proximal domain of leaves in af mutants.

Interaction between cochleata and stipule-reduced mutations results in exstipulate hypertrophied leaves in Pisum sativum L.

In the wild type P. sativum, each of the adult plant stem nodes, bears a pair of sessile foliaceous stipules and a petiolated unipinnately compound leaf of 4 to 6 leaflets and 7-9 tendrils. The stipule-reduced (st) and cochleata (coch) single null mutants and coch st double null mutant differ fom the wild type in respectively having sessile stipules of much reduced size, petiolated simple and/or compound leaf-like stipules and no stipules. It is also known that coch leaves are somewhat bigger than st and wild type leaves. Here, pleiotropic phenotype of coch st double mutant was investigated. The morphologies of stipules and leaf were quantified in the field grown plants and microcultured shoots, latter in the presence and absence of gibberellic acid and N-1-naphthylphthalamic acid. The observations showed that as compared to the corresponding plants or shoots of COCH ST (WT) genotype, (a) coch st plants bore leaves in which all the organs were hypertrophied; (b) full complement of leaflets and 3-5 tendrils were formed on leaf; (c) the microcultured coch st shoots were taller despite lower number of nodes, and (d) they also produced leaves in which all the organs were bigger and the ratio of leaflets/tendrils was higher. It was concluded that in coch st double mutant (a) ST function is essential for stipule primordium differentiation, in the absence of COCH function and (b) absence of negative feedback loops between simple stipules and compound leaf for metabolite utilization allows hypertrophied growth in leaves.

The lld mutation in Pisum sativum used as a genetic tool to discern the plant leaflet/leaf developmental process.

Leaves of P. sativum the double mutant genotype tendril-less (tl) leaflet-development (lld), due to the action of lld mutation, produce many leaflets that are aborted at different stages of development. Morphological, vein pattern and histological observations showed that aborted leaflets became cup/bell/trumpet (cup) shaped because of segmental differentiation in the leaflet primordium. Cup’s inside lamina surface was adaxial and outer surfaces of cup and its stem were abaxial. The lld cups were phenotypically homologous to aborted leaves described in Arabidopsis thaliana mutants, angustifolia and those which underexpressed the HD-ZIP III proteins. Leaflet primordium was found to grow and establish three dimensional polarities apex-downwards. Primordium produced lateral outgrowth on one side of midvein. Differentiation, in the outgrowth, of secondary veins, whose xylem tissues faced each other, established the adaxial-abaxial polarity. Lateral outgrowth then developed a cavity which got bounded by future adaxial epidermis. Further growth, veinlet formation, differentiation of palisade parenchyma and spongy parenchyma followed. Opening of lateral outgrowth at its outer midline produced a flat leaflet with lateral lamina spans. The structural and functional correspondence between leaflet and simple leaves suggested commonality between leaf and leaflet development mechanisms. A molecular model for the lld led leaflet abortion was also provided.