The green synthesis of silver nanoparticles (AgNPs) and their applications have attracted many researchers as the AgNPs are used effectively in targeting specific tissues and pathogenic microorganisms. The purpose of this study is to synthesize and characterize silver nanoparticles from fully expanded leaves of Eugenia roxburghii DC., as well as to test their effectiveness in inhibiting biofilm production. In this study, at 0.1 mM concentration of silver nitrate (AgNO3), stable AgNPs were synthesized and authenticated by monitoring the color change of the solution from yellow to brown, which was confirmed with spectrophotometric detection of optical density. The crystalline nature of these AgNPs was detected through an X-Ray Diffraction (XRD) pattern. AgNPs were characterized through a high-resolution transmission electron microscope (HR-TEM) to study the morphology and size of the nanoparticles (NPs). A new biological approach was undertaken through the Congo Red Agar (CRA) plate assay by using the synthesized AgNPs against biofilm production. The AgNPs effectively inhibit biofilm formation and the biofilm-producing bacterial colonies. This could be a significant achievement in contending with many dynamic pathogens.

Ginger (Zingiber officinale Roscoe) is an economically important plant, valued all over the world. The existing variation among 16 promising cultivars as observed through differential rhizome yield (181.9 to 477.3 g) was proved to have a genetic basis using different genetic markers such as karyotype, 4C nuclear DNA content and random amplified polymorphic DNA (RAPD). The karyotypic analysis revealed a differential distribution of A, B, C, D and E type of chromosomes among different cultivars as represented by different karyotype formulas. A significant variation of 4C DNA content was recorded in ginger at an intraspecific level with values ranging from 17.1 to 24.3 pg. RAPD analysis revealed a differential polymorphism of DNA showing a number of polymorphic bands ranging from 26 to 70 among 16 cultivars. The RAPD primers OPC02, OPA02, OPD20 and OPN06 showing strong resolving power were able to distinguish all 16 cultivars. The extent of genetic diversity among these cultivars was computed through parameters of gene diversity, sum of allele numbers per locus and Shannon's information indices. Cluster analysis, Nei's genetic similarity and genetic distances, distribution of cultivars into special distance classes and principal coordinate analysis and the analysis of molecular variance suggested a conspicuous genetic diversity among different cultivars studied. The genetic variation thus detected among promising cultivars of ginger has significance for ginger improvement programs.

No abstract

A protocol was developed for the in vitro propagation of ginger (Zingiber officinale) cv. Suprava using dormant axillary buds from unsprouted rhizomes. The dormant axillary buds embedded in the rhizome nodes were induced to sprout when cultured on MS medium supplemented with 6-benzyladenine (BA) alone (1Ð6 mg/l) or with a combination of BA (1Ð 6 mg/l) and indole-3-acetic acid (IAA) (0.5, 1 mg/l). In vitro sprouted buds were transferred to the multiplication medium containing various combinations of auxins and cytokinins. MS basal medium supplemented with BA (1 mg/l), IAA (1 mg/l) and adenine sulfate (100 mg/l) was found optimum for the in vitro multiplication of shoots producing (8.2 ð 0.2) shoots from a single explant within 30 days of culture. The multiplication rate remained unchanged in subsequent subcultures. Rooting of shoots occurred in the same multiplication media. Upon transfer of the in vitro culture to ex vitro in pots, 96% of plants survived and established successfully under natural conditions. Tissue culture-raised plantlets of ginger could be conserved in vitro through subculturing at an interval of 4 months. The genetic stability of micropropagated clones was evaluated at regular intervals of 6 months up to 24 months in culture using cytophotometric estimation of 4C nuclear DNA content and random amplified polymorphic DNA (RAPD) analysis. Cytophotometric analysis revealed a unimodal distribution of the DNA content with a peak corresponding to the 4C value (23.1 pg), and RAPD analysis revealed monomorphic bands showing the absence of polymorphism in all fifty regenerants analyzed, thus confirming the genetic uniformity among in vitro grown somaclones of Z. officinale. This study is of commercial significance as axillary bud explants are available throughout the year for initiating a fresh culture of the elite ginger cv. Suprava to be used as a source of true-to-type disease-free planting material thereby minimizing the adverse effect of repeated subculturing from the same explant source.

-Genetic diversity was evaluated among 14 cultivars of Catharanthus roseus using RAPD and ISSR markers. The RAPD primers resulted in the amplification of 56 bands, among which 46 (82%) bands were polymorphic Four ISSR primers amplified 31 loci out of which 17 were polymorphic and 14 are monomorphic. The Jaccard's similarity derived from the combined marker system showed that the varieties First Kiss Coral and Cooler Orchid were the most closely related cultivars, with 98% similarity. In the dendrogram constructed on the basis of both RAPD and ISSR data two clear clusters were obtained. The smaller cluster included C. roseus Cv Blue Pearl and C. roseus Cv. Patricia White and the larger cluster was subdivided into two sub clusters with C. roseus Cv. First Kiss Polka Dot isolated from the rest of the cultivars. This may be useful for breeding for improved quality.