Publications by authors named "Avishek Banik"

18 Publications

  • Page 1 of 1

Exploring tea (Camellia sinensis) microbiome: Insights into the functional characteristics and their impact on tea growth promotion.

Microbiol Res 2021 Oct 9;254:126890. Epub 2021 Oct 9.

Laboratory of Microbial Interaction, School of Biotechnology, Presidency University, Kolkata, West Bengal, India. Electronic address:

Tea (Camellia sinensis) is perhaps the most popular and economic beverage in the globe due to its distinctive fragrance and flavour generated by the leaves of commercially farmed tea plants. The tea microbiome has now become a prominent topic of attention for microbiologists in recent years as it can help the plant for soil nutrient acquisition as well as stress management. Tea roots are well known to be colonized by Arbuscular Mycorrhizal Fungi (AMF) and many other beneficial microorganisms that boost the growth of the tea which increases leaf amino acids, protein, caffeine, and polyphenols content. One of the primary goals of rhizosphere microbial biology is to aid in the establishment of agricultural systems that provide high quantities of the food supply while minimizing environmental effects and anthropogenic activities. The present review is aimed to highlight the importance of microbes (along with their phylogeny) derived from cultivated and natural tea rhizospheres to understand the role of AMF and rhizospheric bacterial population to improve plant growth, enhancement of tea quality, and protecting tea plants from pathogens. This review also summarizes recent advances in our understanding of the diversity and profile of tea-associated bacteria. The utilization of the tea microbiome as a "natural resource" could provide holistic development in tea cultivation to ensure sustainability, highlighting knowledge gaps and future microbiome research.
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http://dx.doi.org/10.1016/j.micres.2021.126890DOI Listing
October 2021

Tea and its phytochemicals: Hidden health benefits & modulation of signaling cascade by phytochemicals.

Food Chem 2022 Mar 9;371:131098. Epub 2021 Sep 9.

Laboratory of Microbial Interaction, School of Biotechnology, Presidency University, Kolkata, West Bengal, India. Electronic address:

Tea, one of the most widely consumed beverages, is prepared from the leaves of the Camellia sinensis. The promising health recompenses of tea have been linked to its different phenolic components, which have diverse biological characteristics. Tea also contains several flavonoids, alkaloids, phenolic, theanine, etc., which are associated with anti-oxidant characteristics and a variety of health benefits. It can also lower the pervasiveness of neurological disorders as well as prevent different types of cancer, metabolic syndromes, cardiovascular diseases, urinary stone, obesity, type 2 diabetes. Keeping in mind that tea helps to improve health and prevents many diseases, its consumption has been regarded as a "health-promoting habit" and current medical investigators have established the scientific basis for this concept over time. The current review provides new updated information and perspectives on the tea phytochemicals and their overall health benefits based on molecular processes, experimental studies, and clinical trials.
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http://dx.doi.org/10.1016/j.foodchem.2021.131098DOI Listing
March 2022

Phycoremediation and photosynthetic toxicity assessment of lead by two freshwater microalgae Scenedesmus acutus and Chlorella pyrenoidosa.

Physiol Plant 2021 Sep 8;173(1):246-258. Epub 2021 Mar 8.

School of Biotechnology, Presidency University, Kolkata, India.

Heavy metal (HM) pollution is a serious agro-economic concern and algae can be used as one of the bioremediating agents as it can grow in different water bodies. In this study, the Scenedesmus acutus and Chlorella pyrenoidosa were exposed to various concentrations of Pb for 96 h and a multidimensional toxicity assessment has been performed by pulse amplitude modulation technique and Fourier transform infrared spectroscopy (FTIR). High-angle annular dark-field scanning transmission electron microscopy coupled energy dispersive spectroscopy (HAADF-S/TEM-EDS) detected intracellular localization of Pb , thus confirming algal bio-accumulation abilities. Sensitivity assay demonstrated that 500 and 400 ppm of Pb as minimum inhibitory concentrations (MIC50) for S. acutus and C. pyrenoidosa, respectively, which inhibited growth (OD) by >50% in 96 h. During bioremoval studies, S. acutus and C. pyrenoidosa were found to remove ∼52 and ∼32% of total Pb , respectively. The particulate analysis of Pb by ICP-OES showed >99.5% biosorption capacity by both the species. The biomass characterization by FTIR showed the involvement of various cell wall functional groups such as hydroxyl, alkane, and C=C groups in the biosorption of Pb by both the species. The noninvasive chlorophyll fluorescence techniques provide a quick insight on heavy metal stress and can be adapted as a rapid detection tool to study the Pb stress. S. acutus strain showed higher tolerance and higher bioremoval capacity than C. pyrenoidosa. However, both the species can be exploited for biosorption of Pb from aquatic streams as an alternative way for low cost Pb recovery systems.
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http://dx.doi.org/10.1111/ppl.13368DOI Listing
September 2021

Cadmium biosorption and biomass production by two freshwater microalgae Scenedesmus acutus and Chlorella pyrenoidosa: An integrated approach.

Chemosphere 2021 Apr 27;269:128755. Epub 2020 Oct 27.

School of Biotechnology, Presidency University, Kolkata, West Bengal, India. Electronic address:

Cadmium (Cd) contamination in different water bodies is a matter of serious concern, as it can cause biomagnification in our food chain up to several trophic levels. In this study, Cd toxicity was investigated in the micro-algae Chlorella pyrenoidosa and Scenedesmus acutus exposed to various concentrations of Cd for 96 h. The inhibitory and toxic effects of Cd on growth and photosynthetic parameters of algae were demonstrated. The bioremediation potentials of these algae were investigated and bioremoval mechanisms were confirmed using qualitative electron microscopic assay such as scanning/transmission electron microscope (S/TEM). The photochemical quenching (Fv/Fm), quantum yield (YII), relative electron transfer rate (rETR) and non-photochemical quenching (NPQ) were inhibited significantly and reduced by ≥ 50% of the control at MIC 50 values. The C. pyrenoidosa and S. acutus biomass have shown 30% and 20% reduction in carbon content and 10% and 12% reduction in nitrogen content at MIC50 values of Cd treatment, respectively. During bioremoval studies, C. pyrenoidosa and S. acutus have shown 45.45% and 57.14% Cd removal of Cd from initial concentration of 1.5 ppm. Out of total cadmium removal C. pyrenoidosa was reported 3% bioaccumulation and 97% biosorption. Whereas S. acutus showed 1.5% accumulation and 98.5% biosorption. The S/TEM images showed the surface accumulation and bioaccumulation of cadmium inside the cytoplasm, vacuoles, and chloroplast. Thus cultivating C. pyrenoidosa and S. acutus would be beneficial in Cd contaminated water bodies as they serve the dual purpose by Cd remediation and algal biomass production.
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http://dx.doi.org/10.1016/j.chemosphere.2020.128755DOI Listing
April 2021

Plant Growth-Promoting Traits of a Thermophilic Strain of the Klebsiella Group with its Effect on Rice Plant Growth.

Curr Microbiol 2020 Oct 21;77(10):2613-2622. Epub 2020 May 21.

Department of Microbiology, The University of Burdwan, Burdwan, West Bengal, 713104, India.

In agriculture, instead of synthetic fertilizers, natural bio-inoculants can be used to increase growth and yield of crops. For this purpose, we report a thermophilic bacteria Klebsiella sp. strain PMnew, isolated from Paniphala hot spring. The strain was characterized and assessed for plant growth-promoting traits. Oryza sativa L. var Swarna (rice) seeds were inoculated with the strain to study the bacterization effect on vegetative and reproductive growth of rice plants. The results indicate that PMnew produces organic acids to solubilize phosphate (550.16 ± 0.04 µg/ml), fixes nitrogen, produces indole compounds, siderophore, and ACC deaminase, and shows heavy metal resistance to chromium, cobalt, arsenic, cadmium, and mercury. It also possesses the ability to utilize several monomeric and polymeric sugars as sole carbon source including starch, agar, xylan, gelatin, and pectin, and can grow under both nutrient-rich and deficient conditions. Inoculated rice plants grew twice the length of control plants and surpassed the total grain mass yield of control plants by almost 18 times. Thus, this study brings forth a broad spectrum and easy to cultivate bio-inoculant, which can be used to increase rice production.
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http://dx.doi.org/10.1007/s00284-020-02032-0DOI Listing
October 2020

Efficient Energy Harvesting in SnO-Based Dye-Sensitized Solar Cells Utilizing Nano-Amassed Mesoporous Zinc Oxide Hollow Microspheres as Synergy Boosters.

ACS Omega 2018 Oct 31;3(10):14482-14493. Epub 2018 Oct 31.

Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.

Finding the material characteristics satisfying most of the photovoltaic conditions is difficult. In contrast, utilization of foreign materials that can contribute to light harvesting and charge transfers in the devices is now desirable/thought-provoking. Herein, a binary hybrid photoanode utilizing nano-amassed micron-sized mesoporous zinc oxide hollow spheres (meso-ZnO HS) in conjunction with SnO nanoparticles (NPs), i.e., SnO NP_ZnO HS (for an optimized weight ratio (8:2)), displayed a nearly ∼4-fold increase in the efficiency (η) compared to that of bare SnO nanoparticle device. Enhanced device efficacy in the composite photoanode-based device can be accredited to the dual function of nano-amassed meso-ZnO HS. Nano-amassed micron-sized ZnO HS embedded in the photoanode can increase the light-harnessing capability without sacrificing the surface area as well as optical confinement of light by multiple reflections within its cavity and enhanced light-scattering effects. Electrochemical impedance spectroscopy analysis revealed an extended lifetime of electron (τ) and a higher value of at the working electrode/dye/redox mediator interface, indicating a minimum photoinduced electron interception. The open-circuit voltage decay reveals a slower recombination kinetics of photogenerated electrons, supporting our claim that the nano-ammased meso-ZnO HS can serve as an energy barrier to the photoinjected electrons to retard the back-transfer to the electrolyte. Moreover, the improvement in the fill factors of the composite-based devices is endorsed to the facile penetration of the electrolyte through the pores of nano-amassed meso-ZnO HS, which increases the regeneration probability of oxidized dyes.
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http://dx.doi.org/10.1021/acsomega.8b02520DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6644388PMC
October 2018

Ultrasensitive NO Detection in Simulated Exhaled Air: Enhanced Sensing via Alumina Modification of In-Situ Grown WO Nanoblocks.

Chem Asian J 2019 Dec 27;14(24):4673-4680. Epub 2019 Aug 27.

Department of Chemistry, Indian Institute of Technology, Guwahati, Assam, 781039, India.

Seedless growth of vertically aligned nanostructures, which can induce smoother transport and minimize Ohmic contact between substrate and semiconductor, can be fabricated by in situ growth utilizing modified hydrothermal methods. Such devices can be useful in designing non-invasive ultrasensitive hand-held sensors for diagnostic identification of volatile organic compounds (VOCs) in exhaled air, offering pain-free and easier detection of long-term diseases such as asthma. In the present work, WO nanoblocks, with a high surface area and porosity, have been grown directly over transparent conducting oxide to minimize Ohmic resistance, facilitating smoother electron transfer and enhanced current response. Further modification with porous alumina (γ-Al O ), by electrodeposition, resulted in the selective and ultrasensitive detection of NO in simulated exhaled air. Crystal phase purity of as-fabricated pristine as well modified samples is validated with X-ray diffraction analysis. Morphological and microstructural analyses reveal the successful deposition of porous alumina over the surface of WO . Improved surface area and porosity is presented by porous alumina in the modified WO device, suggesting more active sites for the gas molecules to get adsorbed and diffuse through the pores. Oxygen vacancies, which are detrimental in the transport phenomenon in the presented sensors, have been studied using X-ray photoelectron spectroscopic (XPS) analysis. Gas sensing studies have been performed by fabricating chemiresistor devices based on bare WO and Al O -modified WO . The higher sensitivity for NO gas in case of γ-Al O -modified WO based devices, as compared to bare WO -based devices, is attributed to the better surface area and charge transport kinetics. The presented device strategy offers crucial understanding in the design and development of non-invasive, hand-held devices for NO gas present in the human breath, with potential application in medical diagnostics.
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http://dx.doi.org/10.1002/asia.201900699DOI Listing
December 2019

In Silico and in Vitro Studies of Fluorinated Chroman-2-Carboxilic Acid Derivatives as an Anti-tubercular Agent.

Folia Med (Plovdiv) 2018 Dec;60(4):601-609

Department of Chemistry, Saurashtra University, Rajkot, Gujarat,India.

Background: Despite the use of traditional method, Ugi reaction currently is a well-established multicomponent reaction. Chromane motif itself possesses a variety of biological functions. In order to improve its anti-tubercular activity, it is necessary to modify it accordingly.

Aim: To ensure relation between in silico and in vitro study, we have carried out in vitro screening against H37Rv anti-tubercular agent.

Materials And Methods: Ugi four-component condensation (U-4CCRs) between 6-fluorochroman-2-carboxylic acid, various aryl aldehyde, 3,4,5-trimethoxy amine and tert-butyl isocyanide, gave N-((tert-butylcarbamoyl)(4-substitutedphenyl) methyl)-6-fluoro-N-(3,4,5-trimethoxyphenyl) chroman-2-carboxamide. The molecular level insight of all compounds was carried out by molecular docking study against the receptor tyrosine phosphatase PtpB. All these newly synthesized compounds were screened for their anti-microbial activity against Mycobacterium tuberculosis H37Rv to determine the MIC, IC50 and IC90 of the compound.

Results: The compound 5d also shows large hydrophobic surface contact on the face of the α7-α8 (Ile 207, Phe 211, Met 206, Ile203, Phe161, Phe80, Met126, Tyr130, Val231 and Leu101) that lines one side of the entrance to the active site of the receptor. The compound 5d bind with tyrosine phosphatase PtpB with predicted docking geometric score of 4664, whereas a score of rifampicin was 6586 determined.

Conclusion: From the docking studies, compound 5d, was considered to be the potent inhibitor, which gave strong supportive coordinate with the in vitro study. It is highly active against H37Rv, having MIC and IC50 value of was 70 μM and 53 μM respectively in in vitro study.
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http://dx.doi.org/10.2478/folmed-2018-0034DOI Listing
December 2018

Application of rice (Oryza sativa L.) root endophytic diazotrophic Azotobacter sp. strain Avi2 (MCC 3432) can increase rice yield under green house and field condition.

Microbiol Res 2019 Feb 23;219:56-65. Epub 2018 Nov 23.

Microbiology Laboratory, Crop Production Division, ICAR- National Rice Research Institute, Cuttack, Odisha, 753006, India. Electronic address:

Use of plant-associated beneficial microbes, especially endophytes are getting popular day by day as they occupy a relatively privileged niche inside different plant tissues with lesser competition for food and shelter than rhizosphere. The effects of different physical factors like temperature, rainfall, and seasonal variation and UV radiation on plant growth promoting endophytic communities are less pronounced than those on the rhizospheric and phylloplane microbes. This present work has been compromised with further utilization of an indigenous rice (Oryza sativa L.) root endophytic Azotobacter sp. strain Avi2 (MCC 3432) (AzA) as a bio-formulation for sustainable rice production based on several physiological parameters (plant height, root length/weight, leaf area, yield, chlorophyll contain), in-vitro comparative plant growth promoting assays, greenhouse and field experiments (dry and wet season). Treatments with AzA exhibited higher yield as well as maximal chlorophyll fluorescence (Fm) of flag leaves in flowering and grain filling stages indicating higher photosynthetic rates. Scanning electron microscopic image of rice roots demonstrated accumulation of bacterial biofilm at the junction of primary and lateral root confirming the root-colonizing ability of the bacterium. The results of the study were quite encouraging as AzA exhibited better vegetative and reproductive growth of rice in pot and field experiment compared to formulated rhizospheric Azotobacter sp. (commercial product). Apart from that plants treated with AzA (supplemented 50% nitrogenous fertilizer of recommended dose) exhibited similar yield parameters when it was compared with the recommended dose of fertilizer (RDF; 120:60:60 mg N:P:K kg soil/ without any bacterial). Therefore, it can be concluded that application of this plant growth promoting endophyte can reduce a substantial amount of N-fertilizer for field application.
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http://dx.doi.org/10.1016/j.micres.2018.11.004DOI Listing
February 2019

Characterization of halotolerant, pigmented, plant growth promoting bacteria of groundnut rhizosphere and its in-vitro evaluation of plant-microbe protocooperation to withstand salinity and metal stress.

Sci Total Environ 2018 Jul 23;630:231-242. Epub 2018 Feb 23.

Department of Microbiology, School of Science, RK University, Rajkot 360020, Gujarat, India.

The use of plant associated, indigenous beneficial microbes for sustainable agriculture is getting worldwide acceptance as they successfully colonize at different plant niche under stress conditions to enhance the crop productivity. They also generate several plant growth regulators and protect plants from adversity like presence of salts and metals. In the present study, indigenous, halotolerant, plant growth promoting (PGP) bacterial isolates were isolated from the saline rhizospheric soil of groundnut plants aiming to investigate its in-vitro metal remediation capabilities under saline stress condition. Two pigmented bacteria were selected based on their phenotypic, biochemical, physiological and PGP characters and identified as members of family Bacillaceae (Bacillus and Halobacillus) based on 16S rRNA gene sequence similarity. The pigments were extracted, tested for different antioxidant properties and identified by GC-MS and FT-IR spectra. Simultaneously, both strains exhibited a wide range of salinity (NaCl≥25%), metal resistance (Zinc≈1700mgkg, Aluminium≈1800mgkg, Lead≈1800mgkg), pH (6-10), PGP attributes (indole - 1.05-3.15μgml, ammonia - 0.13-19.95mmolml, nitrite - 0.07-0.26mmolml) and antibiotics sensitivity revealing their wide range of metabolic diversity. In-vitro inoculation of groundnut seedlings with selected isolates under salinity (1% NaCl) and metal (Zn, Al and Pb) stress had a positive impact on different plant physiological parameters (lesser lignification, intact proto xylem and cortical parenchyma) which was correlated with PGP attributes. Microwave plasma atomic emission spectroscopy analysis of seedling samples also detected less amount of metals in plants treated with bacteria indicating, an establishment of plant-microbe protocooperation to withstand salinity and metal stress. This strategy can be implemented to improve crop production in saline metal polluted agriculture fields.
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http://dx.doi.org/10.1016/j.scitotenv.2018.02.227DOI Listing
July 2018

-Symmetric Triphenylamine-Linked Bisthiazole-Based Metal-Free Donor-Acceptor Organic Dye for Efficient ZnO Nanoparticles-Based Dye-Sensitized Solar Cells: Synthesis, Theoretical Studies, and Photovoltaic Properties.

ACS Omega 2017 Sep 20;2(9):5981-5991. Epub 2017 Sep 20.

Department of Chemistry, Indian Institute Technology, Guwahati 781039, Assam, India.

Herein, we have designed a metal-free donor-acceptor dye by incorporating an electron deficient bisthiazole moiety as a linker in between the electron donor triphenylamine and cyanoacetic acid acceptor. The bisthiazole-based organic dye was synthesized using the Pd-catalyzed Suzuki cross-coupling and Knoevenagel condensation reactions. On the basis of the optical, electrochemical, and computational studies, dye showed a better electronic interaction between the donor and acceptor moieties. As-synthesized symmetric triphenylamine-linked bisthiazole-based organic dye has four anchoring groups, which play a significant role for better adsorption on the ZnO surface along with the enhanced kinetics of photoexcited electron injection. Consequently, photovoltaic properties of the organic dye has been carried out by fabricating the ZnO nanoparticles (ZnO NPs)-based solar device. We obtained the maximum incident photon-to-current conversion efficiency of about 56.20%, with a short-circuit photocurrent density ( ) of 13.60 mA cm, which results in a power conversion efficiency (PCE) of 4.94% under AM 1.5 irradiation (100 mW cm). The high PCE value is the result of proficient electron injection from of dye to the conduction band of ZnO NPs, as suggested by the computational calculations. Electrochemical impedance spectroscopy measurement is carried out to calculate the electron lifetime and also reveals the insight to the reduced charge recombinations at the various active interfaces of the photovoltaic device.
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http://dx.doi.org/10.1021/acsomega.7b01100DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6644399PMC
September 2017

Tuning of azine derivatives for selective recognition of Ag with the in vitro tracking of endophytic bacteria in rice root tissue.

Dalton Trans 2016 Dec;45(48):19491-19499

Department of Chemistry, The University of Burdwan, Burdwan, West Bengal, India.

Several azine derivatives have been prepared and structurally characterized by spectroscopic and single-crystal X-ray diffraction analysis. Two of them, viz. naphthalene based (A10) and anthracene based (A11) show fluorescence enhancement in the presence of Ag in aqueous-methanol. Moreover, A11 efficiently tracks Agin vitro endophytic bacteria infected rice root tissue. Experimental results have been substantiated by theoretical DFT calculations.
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http://dx.doi.org/10.1039/c6dt03117jDOI Listing
December 2016

Understanding the role of silica nanospheres with their light scattering and energy barrier properties in enhancing the photovoltaic performance of ZnO based solar cells.

Phys Chem Chem Phys 2016 Oct;18(40):27818-27828

Materials Science Laboratory, Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati - 781039, Assam, India.

The present study discusses the design and development of a dye sensitized solar cell (DSSC) using a hybrid composite of ZnO nanoparticles (ZnO NP) and silica nanospheres (SiO NS). A ≈22% enhancement in the overall power conversion efficiency (PCE, η) was observed for the device fabricated with a binary hybrid composite of 1 wt% SiO NS and ZnO NP compared to the pristine ZnO NP device. A systematic investigation revealed the dual function of the silica nanospheres in enhancing the device efficacy compared to the bare ZnO NP based device. Sub-micron sized SiO NS can boost the light harvesting efficiency of the photoanode by optical confinement, resulting in increased propagation length of the incident light by multiple internal reflections, which was confirmed by UV-Vis diffused reflectance spectroscopy. Electrochemical impedance spectroscopic (EIS) analysis showed a reduced recombination of photo-generated electrons to the I/I redox shuttle in the case of the composite photoanode. The higher recombination resistance (R) in the case of a 1 wt% composite indicates that the SiO NS serves as a partial energy barrier layer to retard the interfacial recombination (back transfer) of photo-generated electrons at the working electrode/electrolyte interface, increasing the device efficiency.
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http://dx.doi.org/10.1039/c6cp05544cDOI Listing
October 2016

Characterization of N2-fixing plant growth promoting endophytic and epiphytic bacterial community of Indian cultivated and wild rice (Oryza spp.) genotypes.

Planta 2016 Mar 22;243(3):799-812. Epub 2015 Dec 22.

Microbiology Laboratory, Crop Production Division, ICAR-Central Rice Research Institute, Cuttack, 753006, Odisha, India.

Main Conclusion: The diversity of endophytic and epiphytic diazotrophs in different parts of rice plants has specificity to the niche (i.e. leaf, stem and root) of different genotypes and nutrient availability of the organ. Inoculation of the indigenous, polyvalent diazotrophs can facilitate and sustain production of non-leguminous crops like rice. Therefore, N2-fixing plant growth promoting bacteria (PGPB) were isolated from different parts of three Indian cultivated [Oryza sativa L. var. Sabita (semi deep/deep water)/Swarna (rain fed shallow lowland)/Swarna-Sub1(submergence tolerant)] and a wild (O. eichingeri) rice genotypes which respond differentially to nitrogenous fertilizers. Thirty-five isolates from four rice genotypes were categorized based on acetylene reduction assay on nitrogenase activity, biochemical tests, BIOLOG and 16S rRNA gene sequencing. The bacteria produced 9.36-155.83 nmole C2H4 mg(-1) dry bacteria h(-1) and among them nitrogenase activity of 11 potent isolates was complemented by nifH-sequence analysis. Phylogenetic analysis based on 16S rDNA sequencing divided them into five groups (shared 95-100 % sequence homology with type strains) belonging to five classes-alpha (Ancylobacter, Azorhizobium, Azospirillum, Rhizobium, Bradyrhizobium, Sinorhizobium, Novosphingobium, spp.), beta (Burkholderia sp.), gamma (Acinetobacter, Aeromonas, Azotobacter, Enterobacter, Klebsiella, Pantoea, Pseudomonas, Stenotrophomonas spp.) Proteobacteria, Bacilli (Bacillus, Paenibacillus spp.) and Actinobacteria (Microbacterium sp.). Besides, all bacterial strains possessed the intrinsic PGP traits of like indole (0.44-7.4 µg ml(-1)), ammonia (0.18-6 mmol ml(-1)), nitrite (0.01-3.4 mol ml(-1)), and siderophore (from 0.16-0.57 μmol ml(-1)) production. Inoculation of rice (cv. Swarna) seedlings with selected isolates had a positive impact on plant growth parameters like shoot and root elongation which was correlated with in vitro PGP attributes. The results indicated that the diverse polyvalent phytonic PGP bacteria, which may be exploited as bio-inoculants to improve rice production.
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http://dx.doi.org/10.1007/s00425-015-2444-8DOI Listing
March 2016

Dual mode ratiometric recognition of zinc acetate: nanomolar detection with in vitro tracking of endophytic bacteria in rice root tissue.

Dalton Trans 2016 Jan;45(2):599-606

Department of Chemistry, The University of Burdwan, Burdwan, West Bengal, India.

Several naphthalene-based aldazine derivatives were developed as efficient colorimetric and fluorescence probes for selective ratiometric recognition of traces of zinc acetate. The derivative structures were characterized by single-crystal X-ray diffraction. The probes were used for in vitro tracking of zinc acetate in endophytic bacteria within rice root tissue and to image zinc acetate in human breast cancer cells (MCF7) by normal and fluorescence microscopy. Density functional theoretical studies were in close agreement with the experimental findings.
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http://dx.doi.org/10.1039/c5dt03431kDOI Listing
January 2016

Envelope protein gene based molecular characterization of Japanese encephalitis virus clinical isolates from West Bengal, India: a comparative approach with respect to SA14-14-2 live attenuated vaccine strain.

BMC Infect Dis 2013 Aug 8;13:368. Epub 2013 Aug 8.

Background: Increasing virulence of Japanese encephalitis virus (JEV), a mosquito-borne zoonotic pathogen is of grave concern because it causes a neurotrophic killer disease Japanese Encephalitis (JE) which, in turn, is responsible globally for viral acute encephalitis syndrome (AES). Despite the availability of vaccine, JE/AES cases and deaths have become regular features in the different rural districts of West Bengal (WB) state, India, indicating either the partial coverage of vaccine or the emergence of new strain of JEV. Therefore, a study was undertaken to characterize and compare the complete envelope (E) protein gene based molecular changes/patterns of JEVs circulating in WB.

Methods: Total of 98 AES case-patients' samples were tested to detect the presence of JEV specific immunoglobulin M (IgM) antibody by Mac-ELISA method. Only JEV IgM negative samples with a history of ≤3 days' illness were screened for virus isolation and RT-PCR. E gene sequences of JEV isolates were subjected to molecular phylogeny and immunoinformatics analysis.

Results: Present study confirmed JEV etiology in 39.7% and 29.1% of patients presenting ≤15 days' febrile illness, as determined by Mac-ELISA and RT-PCR respectively. Phylogenetic analysis based on complete E gene sequences of JEV isolates showed the co-circulation of JEV genotype I (GI) with genotype III (GIII). This study also demonstrated that isolate-specific crucial amino acid substitutions were closely related to neurovirulence/neuroinvasiveness of JE. On the basis of immunoinformatics analysis, some substitutions were predicted to disrupt T-cell epitope immunogenicity/antigenicity that might largely influence the outcome of vaccine derived from JEV GIII SA14-14-2 strain and this has been observed in a previously vaccinated boy with mild JE/AES due to JEV GI infection.

Conclusions: Based on molecular evolutionary and bioinformatic approaches, we report evolution of JEV at a local level. Such naturally occurring evolution is likely to affect the disease profile and the vaccine efficacy to protect against JEV GI may demand careful evaluation.
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http://dx.doi.org/10.1186/1471-2334-13-368DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3751164PMC
August 2013

FRET based tri-color emissive rhodamine-pyrene conjugate as an Al3+ selective colorimetric and fluorescence sensor for living cell imaging.

Dalton Trans 2013 Oct 8;42(37):13311-4. Epub 2013 Aug 8.

Department of Chemistry, The University of Burdwan, 713104, Burdwan, West Bengal, India.

A rhodamine-pyrene hybrid molecule acts as a colorimetric and fluorimetric sensor for Al(3+) through time dependent PET-CHEF and FRET processes associated with tri-color emission. Intracellular Al(3+) has been visualized through time dependent blue-green-red emission. The lowest limit of detection for Al(3+) is 0.02 μM.
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http://dx.doi.org/10.1039/c3dt51752gDOI Listing
October 2013

Antipyrine based arsenate selective fluorescent probe for living cell imaging.

Anal Chem 2013 Feb 18;85(3):1778-83. Epub 2013 Jan 18.

Department of Chemistry, The University of Burdwan, Burdwan, West Bengal, India.

Condensation of salicylaldehyde and 4-aminoantipyrine has yielded a new fluorescent probe (APSAL) capable of detecting intracellular arsenate at the micromolar level for the first time. The structure of the probe has been established by different spectroscopic techniques and confirmed from X-ray crystallography. Common anions, viz., F(-), Cl(-), Br(-), I(-), N(3)(-), NCO(-), NO(2)(-), NO(3)(-), SCN(-), CN(-), CH(3)COO(-), SO(4)(2-), ClO(4)(-), and HPO(4)(2-) do not interfere. The binding constant of APSAL for H(2)AsO(4)(-) has been determined using the Benesi-Hildebrand equation as 8.9 × 10(3) M(-1). Fluorescence quantum yield of APSAL (0.016) increases more than 12 times upon binding arsenate ion.
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http://dx.doi.org/10.1021/ac3031338DOI Listing
February 2013
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