Showing papers by "North Eastern Hill University published in 2015"

Mapping the intellectual structure of scientometrics: a co-word analysis of the journal Scientometrics (2005---2010)

Abstract: 959 full text articles has been studied to explore the intellectual structure of scientometrics in the period 2005---2010 using text mining and co-word analysis. The trends and patterns of scientometrics in the journal Scientometrics were revealed by measuring the association strength of selected keywords which represent the produced concept and idea in the field of scientometrics. All articles were collected from the journal Scientometrics through Springerlink (full text database) and keywords were added non-parametrically from the LISA database and the articles themselves (keywords provided by author). Other important keywords are extracted from the title and abstract of the article manually. These keywords are standardized using a vocabulary tool. With the objective of delineating dynamic changes of the field of scientometrics, the period 2005---2010 was studied and further divided into two consecutive periods: 2005---2007 and 2008---2010. The results show that publication has some well-established topics which are changing gradually to adopt new themes.

Modelling Hotspots for Invasive Alien Plants in India.

Abstract: Identification of invasion hotspots that support multiple invasive alien species (IAS) is a pre-requisite for control and management of invasion. However, till recently it remained a methodological challenge to precisely determine such invasive hotspots. We identified the hotspots of alien species invasion in India through Ecological Niche Modelling (ENM) using species occurrence data from the Global Biodiversity Information Facility (GBIF). The predicted area of invasion for selected species were classified into 4 categories based on number of model agreements for a region i.e. high, medium, low and very low. About 49% of the total geographical area of India was predicted to be prone to invasion at moderate to high levels of climatic suitability. The intersection of anthropogenic biomes and ecoregions with the regions of 'high' climatic suitability was classified as hotspot of alien plant invasion. Nineteen of 47 ecoregions of India, harboured such hotspots. Most ecologically sensitive regions of India, including the 'biodiversity hotspots' and coastal regions coincide with invasion hotspots, indicating their vulnerability to alien plant invasion. Besides demonstrating the usefulness of ENM and open source data for IAS management, the present study provides a knowledge base for guiding the formulation of an effective policy and management strategy for controlling the invasive alien species.

Actinobacterial diversity in limestone deposit sites in Hundung, Manipur (India) and their antimicrobial activities

Abstract: Studies on actinobacterial diversity in limestone habitats are scarce This paper reports profiling of actinobacteria isolated from Hundung limestone samples in Manipur, India using ARDRA as the molecular tool for preliminary classification A total of 137 actinobacteria were clustered into 31 phylotypic groups based on the ARDRA pattern generated and representative of each group was subjected to 16S rRNA gene sequencing Generic diversity of the limestone isolates consisted of Streptomyces (15 phylotypic groups), Micromonospora (4), Amycolatopsis (3), Arthrobacter (3), Kitasatospora (2), Janibacter (1), Nocardia (1), Pseudonocardia (1) and Rhodococcus (1) Considering the antimicrobial potential of these actinobacteria, 19 showed antimicrobial activities against at least one of the bacterial and candidal test pathogens, while 45 exhibit biocontrol activities against at least one of the rice fungal pathogens Out of the 137 actinobacterial isolates, 118 were found to have at least one of the three biosynthetic gene clusters (PKS-I, PKS-II, NRPS) The results indicate that 86% of the strains isolated from Hundung limestone deposit sites possessed biosynthetic gene clusters of which 40% exhibited antimicrobial activities It can, therefore, be concluded that limestone habitat is a promising source for search of novel secondary metabolites

Regulatory capital and risk of Indian banks: a simultaneous equation approach

Abstract: Purpose – This paper aims to examine the association between regulatory capital and risk of Indian commercial banks and the impacts of other relevant variables on them. Design/methodology/approach – The study is based on a secondary data set on Indian commercial banks collected from “Capitaline Plus” corporate database and annual reports of the respective banks. Total 41 major Indian banks (21 public and 20 private sector banks) are considered in this study. Here absolute values of capital and risk are used as dependent variables along with some relevant bank specific explanatory variables in a system of a two-equation model. Based on the nature of interrelationship and identifiability of the equations, three-stage least squares (3SLS) technique is used to estimate the relationship. Findings – Risk and capital of Indian commercial banks are inversely associated. The influence of profitability on both capital and risk is significantly positive. Moreover, human capital efficiency is negatively associated wi...

Improved photo-luminescence behaviour of Eu3+ activated CaMoO4 nanoparticles via Zn2+ incorporation

Abstract: Zn2+ (0, 2, 5, 7 and 10 at%) co-doped CaMoO4:2Eu3+ nanophosphors have been synthesized via the polyol method using ethylene glycol (EG) as both capping agent and reaction medium at 150 °C. From XRD analysis, all 900 °C annealed Zn co-doped CaMoO4:Eu3+ nanophosphors have a tetragonal scheelite phase. Some extra phase evolution has been observed for the as-prepared Zn doped samples. The intensity and crystallinity of XRD patterns increase as heat treatment increases to 900 °C. The valence states of the involved compositions (Zn co-doped CaMoO4:Eu) were investigated by X-ray photoelectron spectroscopy (XPS) and it was found that Ca, Mo, Eu and Zn are in their +2, +6, +3 and +2 oxidation states, respectively. TG-DSC studies of the as-prepared samples corroborate their thermal stability. A TEM (Transmission electron microscopy) study reveals that the particles have spherical morphology. Photoluminescence studies have been carried out under ∼266, and 395 nm excitation wavelengths. Zn co-doping in the CaMoO4:Eu matrix produces a high distortion and modifies the crystal field around the Eu3+ ion and improves the PL intensity. CIE co-ordinates of the 900 °C annealed 10 at% Zn co-doped CaMoO4:Eu sample under 266 nm excitation is x = 0.64 and y = 0.35, which are close to the standard of NTSC (x = 0.67 and y = 0.33). These investigations reveal that Zn co-doped CaMoO4:Eu3+ nano-materials can be used as potential red emitting phosphors, an area which is a bottleneck in the development of low cost LEDs.

Efficacy of RAPD, ISSR and DAMD markers in assessment of genetic variability and population structure of wild Musa acuminata colla

Abstract: North east India is considered as one of the major biodiversity hotspots worldwide and centre of origin of several plant species including Musa. Musa acuminata Colla is known to be one of the wild progenitors of cultivated bananas and plantains. Three single primer based DNA marker techniques viz., random amplified polymorphic DNA (RAPD), inter simple sequence repeat (ISSR) and directed amplification of minisatellites DNA (DAMD) were used for diversity diagnostics among 25 genotypes of wild M. acuminata collected from Meghalaya province of north east India. A total of 58 primers (26-RAPD, 21-ISSR, and11-DAMD) yielded 451 DNA fragments, of which 395 (87.58 %) were found to be polymorphic in nature. The polymorphic information content (PIC) values were almost identical for each marker system. The resolving power of the marker system was found to be highest in RAPD (3.96) whereas ISSR resolved highest marker index (16.39) in the study. Selected amplicon data obtained through single primer amplification reactions were utilized for determination of diversity within and among the populations of M. acuminata. Nei's genetic differentiation (Gst) value (0.451) indicated higher proportion of the genetic variation within the populations which is supported by the AMOVA analysis (88 %). The study provides insight into the efficacy of RAPD, ISSR and DAMD to analyse the genetic variation existing in the wild Musa germplasm, which can further be exploited for quality trait improvement and domestication of such important horticultural crops. The genetic diversity based population structure may shed light on the genetic basis of speciation and evolution of various species within the genus Musa.

Synthesis and evaluation of new salicylaldehyde-2-picolinylhydrazone Schiff base compounds of Ru(II), Rh(III) and Ir(III) as in vitro antitumor, antibacterial and fluorescence imaging agents

Abstract: Reaction of salicylaldehyde-2-picolinylhydrazone (HL) Schiff base ligand with precursor compounds [{(p-cymene)RuCl2}2] 1, [{(C6H6)RuCl2}2] 2, [{Cp*RhCl2}2] 3 and [{Cp*IrCl2}2] 4 yielded the corresponding neutral mononuclear compounds 5-8, respectively. The in vitro antitumor evaluation of the compounds 1-8 against Dalton's ascites lymphoma (DL) cells by fluorescence-based apoptosis study and by their half-maximal inhibitory concentration (IC50) values revealed the high antitumor activity of compounds 3, 4, 5 and 6. Compounds 1-8 render comparatively lower apoptotic effect than that of cisplatin on model non-tumor cells, i.e., peripheral blood mononuclear cells (PBMC). The antibacterial evaluation of compounds 5-8 by agar well-diffusion method revealed that compound 6 is significantly effective against all the eight bacterial species considered with zone of inhibition up to 35 mm. Fluorescence imaging study of compounds 5-8 with plasmid circular DNA (pcDNA) and HeLa RNA demonstrated their fluorescence imaging property upon binding with nucleic acids. The docking study with some key enzymes associated with the propagation of cancer such as ribonucleotide reductase, thymidylate synthase, thymidylate phosphorylase and topoisomerase II revealed strong interactions between proteins and compounds 5-8. Conformational analysis by density functional theory (DFT) study has corroborated our experimental observation of the N, N binding mode of ligand. Compounds 5-8 exhibited a HOMO (highest occupied molecular orbital)-LUMO (lowest unoccupied molecular orbital) energy gap 2.99-3.04 eV. Half-sandwich ruthenium, rhodium and iridium compounds were obtained by treatment of metal precursors with salicylaldehyde-2-picolinylhydrazone (HL) by in situ metal-mediated deprotonation of the ligand. Compounds under investigation have shown potential antitumor, antibacterial and fluorescence imaging properties. Arene ruthenium compounds exhibited higher activity compared to that of Cp*Rh/Cp*Ir in inhibiting the cancer cells growth and pathogenic bacteria. At a concentration 100 µg/mL, the apoptosis activity of arene ruthenium compounds, 5 and 6 (~30 %) is double to that of Cp*Rh/Cp*Ir compounds, 7 and 8 (~12 %). Among the four new compounds 5-8, the benzene ruthenium compound, i.e., compound 6 is significantly effective against the pathogenic bacteria under investigation.

Biological Activity of Endophytic Fungi of Rauwolfia serpentina Benth: An Ethnomedicinal Plant Used in Folk Medicines in Northeast India

Abstract: Rauwolfia serpentina Benth is an ethnomedicinal plant used as anti-hypertensive remedy by the ethnic tribes of northeast India. The plant was screened for the endophytic fungi and their associated biological activities to assess if these fungi have any significant hypocholesterolemic, anti-oxidant and antimicrobial activities. The endophytes were characterized as Colletotrichum gloeosporioides, Penicillium sp. and Aspergillus awamori, from a total 15 isolates, using biochemical and molecular approaches. The colonization rate of endophytes in the leaf and the stem was found to be 12.04 and 4.02 % respectively. C. gloeosporioides was found to be the dominant fungus with an average colonization frequency of 6.8 % followed by Penicillium sp. (3.8 %) and A. awamori (2.1 %). Being the most potential isolate, Penicillium sp. showed the promising hypocholesterolemic activity. The antimicrobial potential against four pathogenic bacteria, viz., Streptococcus pyogenes, Escherichia coli, Enterococcus faecalis, Salmonella enterica ser paratyphi and three fungal pathogens, viz, Candida albicans, Emericella nidulans var nidulans, Fusarium oxysporum showed promising antagonistic ability. A. awamori showed the highest antioxidant potential and also had the maximum phenolic content among the characterized endophytes. This investigation revealed that the endophytic fungal extracts can be a potential source of alternative natural hypocholesterolemic, antimicrobials and antioxidant agents mimicking the activity of the host plant and purification of active metabolites may provide lead molecule of pharmaceutical importance.

Phyto-molecular profiling and assessment of antioxidant activity within micropropagated plants of Dendrobium thyrsiflorum: a threatened, medicinal orchid

Abstract: The escalating loss of biological diversity throughout the world has become a major concern for the conservation biologists Like other threatened plant species, the natural populations of the orchids are also severely threatened Dendrobium thyrsiflorum is one such representative of the family Orchidaceae whose natural populations are getting destroyed at an alarming rate and deserves special conservation attention Both direct shoot organogenesis (DSO) and indirect shoot organogensesis (ISO) pathways were experimented and the highest regeneration frequency for DSO and ISO pathways were found to be 862 and 96 % respectively The regenerated shoots were best rooted in half-strength MS medium supplemented with 1 mg/l indole butyric acid (IBA) and 05 mg/l phloroglucinol The genetic stability of the acclimatized plants derived from ISO and DSO pathways was assessed using Inter Simple Sequence Repeats (ISSR) and Start Codon Targeted (SCoT) molecular markers SCoT proved to be a superior marker over ISSR in detecting clonal variability The phytochemical analysis of the micropropagated plants also revealed a comprehensively higher yield of various secondary metabolites with significantly higher antioxidant potentials in both ISO- and DSO-derived plants over the mother plant However, the ISO-derived plants were more phytochemically enriched compared to the DSO-plants The rapid multiplication rate, higher genetic stability and secondary metabolite production ensures the utility of this micropropagation method for D thyrsiflorum in the ex situ conservation and commercial exploitation of other important orchid species

Heavy metal removal from multicomponent system by the cyanobacterium Nostoc muscorum: kinetics and interaction study.

Abstract: In this study, Nostoc muscorum, a native cyanobacterial species isolated from a coal mining site, was employed to remove Cu(II), Zn(II), Pb(II) and Cd(II) from aqueous solution containing these metals in the mixture. In this multicomponent study, carried out as per the statistically valid Plackett-Burman design of experiments, the results revealed a maximum removal of both Pb(II) (96.3 %) and Cu(II) (96.42 %) followed by Cd(II) (80.04 %) and Zn(II) (71.3 %) at the end of the 60-h culture period. Further, the removal of these metals was attributed to both passive biosorption and accumulation by the actively growing N. muscorum biomass. Besides, the specific removal rate of these metals by N. muscorum was negatively correlated to its specific growth rate. For a better understanding of the effect of these metals on each other’s removal by the cyanobacteria, the results were statistically analyzed in the form of analysis of variance (ANOVA) and Student’s t test. ANOVA of the metal bioremoval revealed that the main (individual) effect due to the metals was highly significant (P value <0.05) on each other’s removal. Student’s t test results revealed that both Zn(II) and Pb(II) strongly inhibited both Cu(II) removal (P value <0.01) and Cd(II) removal (P value <0.02). All these results not only demonstrated a very good potential of the cyanobacteria in the bioremoval of these metals but also the effect of individual metals on each other’s removal in the multicomponent system.

Bioremoval of Cu(II), Zn(II), Pb(II) and Cd(II) by Nostoc muscorum isolated from a coal mining site

Abstract: This study evaluated the potential of the cyanobacterium Nostoc muscorum isolated from a mining environment for the removal of the heavy metals Cu(II), Zn(II), Pb(II) and Cd(II) from a constituent aqueous solution of different initial concentrations (5 to 50 mg L−1). Prior to the metal bioremoval experiments, the effect of three main culture parameters, i.e. inoculum volume, inoculum age and pH, on N. muscorum growth was assessed and their levels optimized employing the Taguchi experimental design technique. The batch metal removal kinetics showed a maximum removal of Pb(II) (98 %) and Cu(II) (87.8 %), followed by Cd(II) (82 %) and Zn(II) (67.2 %) at 5 mg L−1 initial metal concentration. Furthermore, estimation of protein, carbohydrate and biomass contents of the metal-exposed N. muscorum revealed that Zn(II) and Cd(II) are more toxic compared to Cu(II) at all initial metal concentrations, whereas it was more tolerant towards Pb(II).

A new dihydrazone based “turn on” fluorescent sensor for Zn(II) ion in aqueous medium

Abstract: A new simple dihydrazone based colorimetric and fluorescent “turn-on” chemosensor (disalicyladehyde succinoyldihydrazone, I ) for Zn(II) was designed and synthesized. The photophysical behavior of the ligand and metal coordinated complex was characterized by steady state and time-resolved fluorescence, density functional theory calculation in combination with 1 H NMR and mass spectroscopy results. The compound acts as a highly selective and sensitive detector of Zn(II) in aqueous medium with almost six times increase in fluorescence intensity. The optimum condition for sensing ability of I with a detection limit of ca. 2 μM of Zn(II) was found at solution pH 8.6 and at excitation wavelength of 380 nm. The other interfering elements, including Cd(II), show either no or very little change in fluorescence intensity under similar experimental conditions.

Consensus reference gene(s) for gene expression studies in human cancers: end of the tunnel visible?

Abstract: Gene expression studies are increasingly used to provide valuable information on the diagnosis and prognosis of human cancers. Also, for in vitro and in vivo experimental cancer models gene expression studies are widely used. The complex algorithms of differential gene expression analyses require normalization of data against a reference or normalizer gene, or a set of such genes. For this purpose, mostly invariant housekeeping genes are used. Unfortunately, however, there are no consensus (housekeeping) genes that serve as reference or normalizer for different human cancers. In fact, scientists have employed a wide range of reference genes across different types of cancer for normalization of gene expression data. As a consequence, comparisons of these data and/or data harmonizations are difficult to perform and challenging. In addition, an inadequate choice for a reference gene may obscure genuine changes and/or result in erroneous gene expression data comparisons. In our effort to highlight the importance of selecting the most appropriate reference gene(s), we have screened the literature for gene expression studies published since the turn of the century on thirteen of the most prevalent human cancers worldwide. Based on the analysis of the data at hand, we firstly recommend that in each study the suitability of candidate reference gene(s) should carefully be evaluated in order to yield reliable differential gene expression data. Secondly, we recommend that a combination of PPIA and either GAPDH, ACTB, HPRT and TBP, or appropriate combinations of two or three of these genes, should be employed in future studies, to ensure that results from different studies on different human cancers can be harmonized. This approach will ultimately increase the depth of our understanding of gene expression signatures across human cancers.

Molecular characterization of Dendrobium nobile Lindl., an endangered medicinal orchid, based on randomly amplified polymorphic DNA

Abstract: Dendrobium nobile Lindl., is an orchid species of immense biopharmaceutical and horticultural importance. The knowledge of its existent genetic variations within wild accessions is crucial for formulation of sustainable utilization strategies. It is distributed in a large landscape area and can grow at altitudes ranging from 800 to 2,000 m. Given that Orchidaceae is one of the largest families of flowering plants, reports on their existing genetic diversity are extremely limited. Molecular study on D. nobile can provide valuable information about the genetic diversity level and genetic relatedness of this important medicinal orchid species. Knowledge of genetic structure of a species also provides resources of a species with its current feature and future evolutionary potential. The genetic structure of D. nobile from Northeast India was investigated using randomly amplified polymorphic DNA (RAPD).The PIC value of RAPD primers was 0.74 and Rp values ranged between 6.80 and 13.23. Overall the Shannon Index, Global coefficient of genetic differentiation (G ST), showed that relative genetic diversity of the populations was fairly high. However, the low value of gene flow (Nm = 0.27) was revealed by the RAPD marker. The results of analysis of molecular variance (AMOVA) revealed that variation amongst the populations was significantly higher than within the populations. A combination of UPGMA and STRUCTURE analysis was employed to estimate the genetic relationships of D. nobile germplasm; interestingly, both the methods presented similar grouping pattern with few differences. Results revealed that 60 individuals belonging to six natural populations in Northeast India were clustered into two major groups. The data represented in this study suggested that the RAPD method was a valuable tool for estimation of genetic diversity and genetic relatedness of the D. nobile germplasm. The present findings are useful outcomes for germplasm conservation and formulation of new breeding strategies for this extremely important medicinal orchid species.

Genetic Environment of Plasmid Mediated CTX-M-15 Extended Spectrum Beta-Lactamases from Clinical and Food Borne Bacteria in North-Eastern India

Abstract: Background The study investigated the presence of CTX-M-15 type extended spectrum beta-lactamases (ESBL), compared their genetic arrangements and plasmid types in gram negative isolates of hospital and food origin in north-east India. From September 2013 to April 2014, a total of 252 consecutive, non-duplicate clinical isolates and 88 gram negative food isolates were selected. Phenotypic and molecular characterization of ESBL genes was performed. Presence of integrons and gene cassettes were analyzed by integrase and 59 base-element PCR respectively. The molecular environments surrounding blaCTX-M and plasmid types were investigated by PCR and PCR-based replicon typing respectively. Transformation was carried out to assess plasmid transfer. Southern blotting was conducted to localize the blaCTX-M-15 genes. DNA fingerprinting was performed by ERIC-PCR. Results Prevalence of ESBL was found to be 40.8% (103/252) in clinical and 31.8% (28/88) in food-borne isolates. Molecular characterization revealed the presence of 56.3% (58/103) and 53.5% (15/28) blaCTX-M-15 in clinical and food isolates respectively. Strains of clinical and food origin were non-clonal. Replicon typing revealed that IncI1 and IncFII plasmid were carrying blaCTX-M-15 in clinical and food isolates and were horizontally transferable. The ISEcp1 element was associated with blaCTX-M-15 in both clinical and food isolates. Conclusions The simultaneous presence of resistance determinants in non-clonal isolates of two different groups thus suggests that the microbiota of common food products consumed may serve as a reservoir for some of the drug resistance genes prevalent in human pathogens.

Empirical Validity of Value Added Intellectual Coefficient Model in Indian Knowledge-based Sector

Abstract: The purpose of this study is to investigate empirically the validity of the basic propositions of value added intellectual coefficient (VAIC) and extend VAIC models in Indian knowledge-based sector...

Plantlet regeneration of Paris polyphylla Sm. via thin cell layer culture and enhancement of steroidal saponins in mini-rhizome cultures using elicitors

Abstract: An efficient regeneration protocol for the medicinal plant, Paris polyphylla Sm. was developed through the formation of mini-rhizomes (MRs) using transverse thin cell layer (tTCL) culture technique. MRs were induced from tTCL explants derived from the basal and middle stem portions while apical portion failed to show any kind of response. Highest response percentage (86.6 %) of MRs formation with a maximum fresh weight (1.05 ± 0.08 g) was achieved from basal sections cultured on ½ MS medium supplemented with 0.5 mg/l 6-benzylaminopurine (BAP). MRs transferred to plant growth regulator free medium gave rise to shoot buds that eventually regenerated into plantlets and were successfully acclimatized with a survival percentage of more than 95 % under greenhouse conditions. Quantification through reverse-phase HPLC showed 1.41-fold higher content of total steroidal saponins in MRs cultured on medium supplemented with 0.5 mg/l BAP as compared to the field-grown rhizome. Elicitation of MRs liquid culture with chitosan, salicyclic acid (SA) and yeast extract enhanced the production of steroidal saponins but resulted in reduced growth rate. Highest total steroidal saponins content (87.66 ± 1.66 mg/g DW) was achieved in cultures treated with SA at 50 mg/l after 30 days of elicitation which is 3.6 times higher than the in vivo rhizome. The developed protocol would facilitate the conservation of this valuable medicinal plant and could be used as a ready stock to meet the demands of the pharmaceutical industry for steroidal saponins productions.

A Novel Route for the Preparation of Silver Loaded Polyvinyl Alcohol Nanogels for Wound Care Systems

Abstract: This study is aimed at the development of a composite wound dressing containing nanosilver loaded polyvinyl alcohol (PVA) nanogels. The PVA nanogels were prepared by fructose induced reduction of silver nitrate within PVA gel to develop nanosilver nanogel (nGel). The influence of various synthesis parameters on PVA nanogel formation was investigated. The particle size of the nanogels, as evaluated by transmission electron microscopy was observed to be in the range of 10–50 nm. Glycerol was added to the nGel system and this composition, nGel/Glc, was coated on cotton fabric to develop a composite wound dressing. The cumulative release of silver from the dressing was found to be ∼36% of the total loading after 48 h. Even at such low concentrations, high antibacterial efficiency was achieved against both gram positive and gram negative bacteria. In vivo wound healing studies were carried out over a period of 21 days on full-thickness skin wounds created on Swiss albino mice. Fast healing was observed in nGel...

Investigation on the bioactivity of culturable endophytic and epiphytic bacteria associated with ethnomedicinal plants

Abstract: Introduction: The growing need for the bioactive compounds of ethnomedicinal plants for the treatment of diseases has resulted in exploitation of medicinal plants. The present investigation aimed to study the diversity of endophytic and epiphytic bacteria associated with ethnomedicinal plants and to explore their potential as source of bioactive compounds. Methodology: Characterization of culturable endophytic and epiphytic bacteria associated with 11 ethnomedicinal plants and their potential as natural antioxidants was assessed through free radical scavenging activity, total phenolics, total flavonoids, metal ion chelation, and antagonistic activity. Genetic screening to assess the potential of endophytes and epiphytes to synthesize bioactive compounds was achieved by screening for the presence of the non-ribosomal peptide synthetase (NRPS) gene. Result: The frequently isolated endophytic bacterium recovered was Bacillus sp. Antioxidative property of the bacterial extracts revealed endophytes with potent antioxidant activity and better antagonistic activity as compared to epiphytes. Genetic screening revealed the presence of the NRPS gene in seven plant-associated bacteria, indicating the production of natural products. Conclusions: The study indicated the extracts of bacterial endophytes associated with ethnomedicinal plants as good sources of natural products with potential application in oxidative stress. The isolates could be used as new bioactive agents.

Characterization of a Highly pH Stable Chi-Class Glutathione S-Transferase from Synechocystis PCC 6803.

Abstract: Glutathione S-transferases (GSTs) are multifunctional enzymes present in virtually all organisms. Besides having an essential role in cellular detoxification, they also perform various other functions, including responses in stress conditions and signaling. GSTs are highly studied in plants and animals; however, the knowledge regarding GSTs in cyanobacteria seems rudimentary. In this study, we report the characterization of a highly pH stable GST from the model cyanobacterium- Synechocystis PCC 6803. The gene sll0067 was expressed in Escherichia coli (E. coli), and the protein was purified to homogeneity. The expressed protein exists as a homo-dimer, which is composed of about 20 kDa subunit. The results of the steady-state enzyme kinetics displayed protein’s glutathione conjugation activity towards its class specific substrate- isothiocyanate, having the maximal activity with phenethyl isothiocyanate. Contrary to the poor catalytic activity and low specificity towards standard GST substrates such as 1-chloro-2,4-dinitrobenzene by bacterial GSTs, PmGST B1-1 from Proteus mirabilis, and E. coli GST, sll0067 has broad substrate degradation capability like most of the mammalian GST. Moreover, we have shown that cyanobacterial GST sll0067 is catalytically efficient compared to the best mammalian enzymes. The structural stability of GST was studied as a function of pH. The fluorescence and CD spectroscopy in combination with size exclusion chromatography showed a highly stable nature of the protein over a broad pH range from 2.0 to 11.0. To the best of our knowledge, this is the first GST with such a wide range of pH related structural stability. Furthermore, the presence of conserved Proline-53, structural motifs such as N-capping box and hydrophobic staple further aid in the stability and proper folding of cyanobacterial GST- sll0067.

Biotechnological advances on in vitro capsaicinoids biosynthesis in capsicum: a review

Abstract: One of the main characteristics of chili pepper fruit is its pungent taste due to the presence of a group of compounds known as capsaicinoids. Capsaicinoids biosynthesis in chili plant is defined by two pathways: phenylpropanoid, which determines phenolic structure; and fatty acid metabolism, which determines the molecule’s fatty acids. The potency of chili pepper cells, tissue and organ to biosynthesize capsaicinoids in in vitro cultures have been a subject of intensive research. Recent findings demonstrated that manipulation of culture strategies viz., immobilization of cells, precursors feeding, cell selection, elicitors treatments, osmotic stress, influence of calcium channel modulators, nutrient stress, pH stress etc. to enhance the accumulation of capsaicinoids in in vitro cultures of chili pepper have resulted in significant increase. However, the levels of capsaicinoids accumulation in cell cultures have never reached the levels in the fruits and require more efficient strategies to enhance the capsaicinoids biosynthetic activity. The present review highlights a comprehensive overview of capsaicinoids biosynthesis, its clinical applications and consolidated results of studies on biotechnological advances in chili pepper research leading to the biosynthesis of capsaicinoids in in vitro cultures.

Ferrite-supported glutathione: an efficient, green nano-organocatalyst for the synthesis of pyran derivatives

Abstract: An efficient magnetically retrievable ferrite-supported glutathione nano-organocatalyst has been employed for the synthesis of a library of 2-amino-4H-pyran derivatives in aqueous media via a one-pot multicomponent reaction. The highlight of this protocol lies in its operational simplicity, use of greener solvent, high yield within a very short period of time and reusability of the catalyst. This method provides an alternative greener approach for the synthesis of 2-amino-4H-pyran derivatives.