Laxmikanta Acharya

Assessment of Genetic Diversity among 16 Promising Cultivars of Ginger Using Cytological and Molecular Markers

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.

Genetic Stability of Micropropagated Ginger Derived from Axillary Bud through Cytophotometric and RAPD Analysis

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 (1 - 6 mg/l) or with a combination of BA (1 - 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 ± 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.

A comprehensive review on vernal keratoconjunctivitis with emphasis on proteomics

Allergic conjunctivitis presents as a spectrum of different clinical entities, such as perennial allergic conjunctivitis, seasonal allergic conjunctivitis, atopic keratoconjunctivitis and vernal keratoconjunctivitis. Vernal keratoconjunctivitis (VKC) is a disorder that is often associated with allergens and is seen during the spring season. Herein, we focused on vernal keratoconjunctivitis (VKC) and reviewed its epidemiology, clinical presentations, ocular associations, available treatment options, and the progressive understanding of its histopathological features; we have also systematically elaborated on the various studies on proteomics. Initial theories of a solely IgE-mediated mechanism have been replaced by those considering IgE and non-IgE mechanisms. Developments in basic and clinical research will open novel diagnostic approaches for the early detection and cure of the disease.

Genetic diversity and gene differentiation among ten species of Zingiberaceae from Eastern India.

In the present study, genetic fingerprints of ten species of Zingiberaceae from eastern India were developed using PCR-based markers. 19 RAPD (Rapid Amplified polymorphic DNA), 8 ISSR (Inter Simple Sequence Repeats) and 8 SSR (Simple Sequence Repeats) primers were used to elucidate genetic diversity important for utilization, management and conservation. These primers produced 789 loci, out of which 773 loci were polymorphic (including 220 unique loci) and 16 monomorphic loci. Highest number of bands amplified (263) in Curcuma caesia whereas lowest (209) in Zingiber cassumunar. Though all the markers discriminated the species effectively, analysis of combined data of all markers resulted in better distinction of individual species. Highest number of loci was amplified with SSR primers with resolving power in a range of 17.4–39. Dendrogram based on three molecular data using unweighted pair group method with arithmetic mean classified all the species into two clusters. Mantle matrix correspondence test revealed high matrix correlation in all the cases. Correlation values for RAPD, ISSR and SSR were 0.797, 0.84 and 0.8, respectively, with combined data. In both the genera wild and cultivated species were completely separated from each other at genomic level. It also revealed distinct genetic identity between species of Curcuma and Zingiber. High genetic diversity documented in the present study provides a baseline data for optimization of conservation and breeding programme of the studied zingiberacious species.

Molecular characterization of five medicinally important species of Typhonium (Araceae) through random amplified polymorphic DNA (RAPD).

The interrelationship of five medicinally important species of Typhonium (Araceae) including T. venosum, which was previously placed under the genus Sauromatum, was inferred by analysis of random amplified polymorphic DNA (RAPD). DNA from pooled leaf samples was isolated and RAPD analysis was performed using 20 decamer oligonucleotide primers. Out of a total of 245 bands amplified, 12 were found to be monomorphic while 233 bands were polymorphic including 86 species-specific bands. The genetic similarities were analyzed from the dendrogram constructed by the pooled RAPD data using a similarity index. The dendrogram showed two distinct clades, one containing T. roxburghii, T. trilobatum and T. venosum and the other containing the remainder two species, i.e. T. diversifolium and T. flagelliforme. Both the clusters shared a common node approx. at 23.7% level of similarity. The maximum similarity of 31.2% was observed between T. venosum and T. trilobatum. In view of its close genetic similarity with other members of Typhonium, transfer of Sauromatum venosum to the genus Typhonium and merger of the two genera was supported.

Analysis of Genetic Diversity among Selected Grasspea (Lathyrus sativus L.) Genotypes Using RAPD Markers

Randomly amplified polymorphic DNA (RAPD) technique was applied to assess the genetic variability among five selected genotypes of grasspea. Out of 30 random decamer primers tested for the present investigation 20 showed reproducible DNA amplification. A total of 257 loci were amplified of which 159 were polymorphic including 57 genotype-specific unique bands. Amplicons had molecular weights ranging from 3.0 kb to 0.1 kb. Majority amplicons were shared by most of the genotypes which indicated a very narrow genetic gap between them. The dendrogram constructed on the basis of RAPD data showed two clusters. The local genotype collected from Nayagarh was grouped along with IC-120451 and IC-120453, sharing a common node at an 82% similarity level. The other genotypes, IC-120478 and IC-120487, were located in the second clade having a common node at 84% similarity level. The investigation showed that though all the genotypes of grasspea were of apparently similar morphology there exists polymorphism at the molecular level, which can be exploited in breeding programmes aimed at crop improvement.

Separation of the genera in the subtribe Cassiinae (Leguminosae: Caesalpinioidae) using molecular markers

Separation of the genera in the subtribe Cassiinae (Leguminosae: Caesalpinioidae) using molecular markers). Random amplified polymorphic DNA (RAPD), Inter simple sequence repeat (ISSR) and Amplified fragment length polymorphism (AFLP) markers were used to verify the segregation of the genus Cassia L. senso lato into three distinct genera namely Chamaecrista Moench., Senna P. Mill. and Cassia L. sensostricto Eighteen representatives of the three taxa were characterized using the molecular markers. 25 RAPD, six ISSR primers and six AFLP primer combinations resulted in the amplification of 612, 115 and 622 bands (loci) respectively. Most of the loci are found to be polymorphic, showing high degrees of genetic diversity among the different taxa studied. The dendrogram constructed on the basis of the RAPD, ISSR and AFLP data using SHAN clustering, divided Cassia L. senso lato. into three different clusters as Chamaecrista Moench. Senna P. Mill. and Cassia L. senso stricto High bootstrap value revealed that all the clusters were stable and robust. It was observed from the present investigation that these genera have their identity at molecular level, which supports the elevation of the genus Cassia L. senso lato to the level of subtribe Cassiinae and segregation into three distinct genera instead of intrageneric categories.

Assessment of genetic diversity in 31 species of mangroves and their associates through RAPD and AFLP markers.

Random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) markers were used to assess the genetic diversity in 31 species of mangroves and mangrove associates. Four AFLP primer combinations resulted in the amplification of 840 bands with an average of 210 bands per primer combination and 11 RAPD primers yielded 319 bands with an average of 29 bands per primer. The percentage of polymorphism detected was too high indicating the high degree of genetic variability in mangrove taxa both at inter- and intra-generic levels. In the dendrogram, species belonging to a particular family/ genus, taxa inhabiting similar habitats or having similar adaptations tended to be together. There were exceptions too; as many unrelated species of mangroves form clusters. The intrafamilial classification and inter-relationships of genera in the family Rhizophoraceae could be confirmed by molecular analysis. Both the markers RAPD and AFLP were found equally informative and useful for a better understanding of the genetic variability and genome relationships among mangroves and their associated species.

Genome Relationship among Nine Species of Millettieae (Leguminosae: Papilionoideae) Based on Random Amplified Polymorphic DNA (RAPD)

Random amplified polymorphic DNA (RAPD) marker was used to establish intergeneric classification and phylogeny of the tribe Millettieae sensu Geesink (1984) (Leguminosae: Papilionoideae) and to assess genetic relationship between 9 constituent species belonging to 5 traditionally recognized genera under the tribe. DNA from pooled leaf samples was isolated and RAPD analysis performed using 25 decamer primers. The genetic similarities were derived from the dendrogram constructed by the pooled RAPD data using a similarity index, which supported clear grouping of species under their respective genera, inter- and intra-generic classification and phylogeny and also merger of Pongamia with Millettia. Elevation of Tephrosia purpurea var. pumila to the rank of a species (T. pumila) based on morphological characteristics is also supported through this study of molecular markers.

In Silico Biology of H1N1: Molecular Modelling of Novel Receptors and Docking Studies of Inhibitors to Reveal New Insight in Flu Treatment

Influenza is an infectious disease caused by RNA viruses of the family Orthomyxoviridae. The new influenza H1N1 viral stain has emerged by the genetic combination of genes from human, pig, and birds H1N1 virus. The influenza virus is roughly spherical and is enveloped by a lipid membrane. There are two glycoproteins in this lipid membrane; namely, hemagglutinin (HA) which helps in attachment of the viral strain on the host cell surface and neuraminidase (NA) that is responsible for initiation of viral infection. We have developed homology models of both Hemagglutinin and Neuraminidase receptors from H1N1 strains in eastern India. The docking studies of B-Sialic acid and O-Sialic acid in the optimized and energy-minimized homology models show important H-bonding interactions with ALA142, ASP230, GLN231, GLU232, and THR141. This information can be used for structure-based and pharmacophore-based new drug design. We have also calculated ADME properties (Human Oral Absorption (HOA) and % HOA) for Oseltamivir which have been subject of debate for long.