Sanghamitra Nayak

Manganese biomining: A review.

Biomining comprises of processing and extraction of metal from their ores and concentrates using microbial techniques. Currently this is used by the mining industry to extract copper, uranium and gold from low grade ores but not for low grade manganese ore in industrial scale. The study of microbial genomes, metabolites and regulatory pathways provide novel insights to the metabolism of bioleaching microorganisms and their synergistic action during bioleaching operations. This will promote understanding of the universal regulatory responses that the biomining microbial community uses to adapt to their changing environment leading to high metal recovery. Possibility exists of findings ways to imitate the entire process during industrial manganese biomining endeavor. This paper reviews the current status of manganese biomining research operations around the world, identifies factors that drive the selection of biomining as a processing technology, describes challenges in exploiting these innovations, and concludes with a discussion of Mn biominings future.

In vitro multiplication and microrhizome induction in Curcuma aromatica Salisb

Shoot multiplication and plant regeneration was achieved from freshly sprouted shoots of Curcuma aromatica on Murashige and Skoogs medium supplemented with BA alone (1–7 mgL−1) or a combination of BA(1–5 mgL−1) and Kn (0.5–1 mgL−1). A concentration of 5 mgL−1 BA was optimum for shoot multiplication and rooting of shoots. The regenerated plants grew profusely on transfer to liquid medium.In vitro raised plants were successfully established in the field. Microrhizomes were induced at the base of the in vitro derived shoots upon transfer to medium containingvarious combinations and concentrations of sucrose and BA and grown under varying photoperiods. MS basal medium with 5 mgL−1 BA, 60 gL−1 sucrose and an8 h photoperiod was optimum for induction ofmicrorhizomes within 30 days of culture. Harvestedmicrorhizomes stored in moist sand in poly-bagssprouted after 2 months of storage at roomtemperature. For in vitro storage, microrhizomeswere grown in medium containing 0.1 mgL−1 BA.Microrhizome formation was found to be controlled bythe concentrations of BA and sucrose as well asphotoperiod during culture.

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.

Perspectives of genomic diversification and molecular recombination towards R-gene evolution in plants

Plants are under strong evolutionary pressure in developing new and noble R genes to recognize pathogen avirulence (avr) determinants and bring about stable defense for generation after generations. Duplication, sequence variation by mutation, disparity in the length and structure of leucine rich repeats etc., causes tremendous variations within and among R genes in a plant thereby developing diverse recognitional specificity suitable enough for defense against new pathogens. Recent studies on genome sequencing, diversity and population genetics in different plants have thrown new insights on the molecular evolution of these genes. Tandem and segmental duplication are important factors in R gene abundance as inferred from the distribution of major nucleotide binding site-leucine rich repeats (NBS-LRRs) type R-genes in plant genomes. Likewise, R-gene evolution is also thought to be facilitated by cluster formation thereby causing recombination and sequence exchange and resulting in haplotypic diversity. Population studies have further proven that balancing selection is responsible for the maintenance of allelic diversity in R genes. In this review, we emphasize and discuss on improved perspectives towards the molecular mechanisms and selection pressure responsible for the evolution of NBS-LRR class resistance genes in plants.

Plant regeneration from callus culture of Curcuma aromatica and in vitro detection of somaclonal variation through cytophotometric analysis

Callus cultures initiated from shoot base explants of Curcuma aromatica Salisb. were maintained on Murashige and Skoog (MS) media supplemented with 2 mg dm−3 2,4-dichlorophenoxyacetic acid alone or with 0.5 mg dm−3 kinetin. Plantlets were regenerated from 60 and 180-d-old callus on MS media supplemented with 3 mg dm−3 benzyladenine and 0.5 mg dm−3 α-naphthalene acetic acid. Approximately 8–10 plantlets were produced after 30–40 d of culture per 50 mg of callus inoculated. Out of 113 regenerants analyzed 85 plants were exclusively diploid and 28 were predominantly diploid revealing presence of polyploid nuclei. Frequency of polyploid cells were more in regenerants obtained from 180-d-old callus then from 6-d-old callus which might be attributed to the ageing of callus.

Micropropagation of Zingiber rubens and assessment of genetic stability through RAPD and ISSR markers

Protocol was developed for high frequency in vitro multiplication of an endemic species, Zingiber rubens Roxb. The sprouted buds of the rhizomes were cultured on Murashige and Skoog (MS) medium supplemented with 6-benzyladenine (BA; 0.5–5.0 mg dm−3), indole-3-acetic acid (IAA; 0.5–2.0 mg dm−3), kinetin (KIN; 1.0–3.0 mg dm−3), naphthaleneacetic acid (NAA; 0.5–1.0 mg dm−3) and adenine sulphate (ADS; 80–100 mg dm−3). MS basal medium supplemented with 3 mg dm−3 BA and 0.5 mg dm−3 IAA was optimum for shoot elongation. The elongated shoots (1–2 cm) were transferred to multiplication medium containing 2 mg dm−3 BA, 1 mg dm−3 IAA and 100 mg dm−3 ADS. The multiplication rate remained unchanged in subsequent subcultures. Upon ex vitro transfer, 85 % of plants survived. Genetic stability of micropropagated clones were periodically evaluated at an interval of 6 months up to 30 months in culture using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) analysis and genetic uniformity in all regenerants was confirmed.

Chemical Composition of Turmeric Oil (Curcuma longa L. cv. Roma) and its Antimicrobial Activity against Eye Infecting Pathogens

Abstract The essential oil from the rhizomes of Roma cultivar of turmeric (Curcuma longa) from Orissa was examined for its antimicrobial activity against the pathogens causing eye infections. The oil was obtained by hydrodistillation extraction method using Clevenger apparatus. Chemical analysis of the oil was done by using gas chromatography and mass spectrometry (GC/MS). The antimicrobial effects of oil towards Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger were tested by inhibition zone diameter (IZD) test to screen the antimicrobial activity, minimum inhibitory concentration (MIC) test and minimum killing time (MKT) test to determine the minimum concentration of oil and minimum time required to kill the pathogens. Oil showed very good activity against all four microbial strains used at concentration of 10 μL except Pseudomonas aerugenosa. Very low concentration of 1.95 μL/mL oil was needed to inhibit the growth of most highly infecting pathogen Staphylococcus aureus within 15 min of its exposure in comparison to other microbial strains. High turmerone content (49.76%) of elite turmeric cultivar Roma released from Orissa (India) might be assigned to be responsible for such excellent anti microbial activity against the tested pathogens. The purpose of this study is to authenticate the use of turmeric rhizome oil against eye infections so as to giving an approach to formulate turmeric rhizome oil as potential eye drop in place of traditional antibiotics after undertaking its in vivo pharmacological studies.

Phytochemical investigation and in vitro antioxidant activity of an indigenous medicinal plant Alpinia nigra B.L. Burtt.

Objective To investigate antioxidant potential of methanol extract of Alpinia nigra leaves.

Recent advances in biosensor based diagnosis of urinary tract infection

Urinary tract infections (UTIs) are potentially life threatening infections that are associated with high rates of incidence, recurrence and mortality. UTIs are characterized by several chronic infections which may lead to lethal consequences if left undiagnosed and untreated. The uropathogens are consistent across the globe. The most prevalent uropathogenic gram negative bacteria are Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Klebsiella pneumonia. Early detection and precise diagnosis of these infections will play a pivotal role in health care, pharmacological and biomedical sectors. A number of detection methods are available but their performances are not upto the mark. Therefore a more rapid, selective and highly sensitive technique for the detection and quantification of uropathogen levels in extremely minute concentrations need of the time. This review brings all the major concerns of UTI at ones doorstep such as clinical costs and incidence rate, several diagnostic approaches along with their advantages and disadvantages. Paying attention to detection approaches with emphasizing biosensor based recent developments in the quest for new diagnostics for UTI and the need for more sophisticated techniques in terms of selectivity and sensitivity is discussed.

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.