Exopolysaccharides from agriculturally important microorganisms: Conferring soil nutrient status and plant health.

A wide variety of microorganisms secretes extracellular polymeric substances or commonly known as exopolysaccharides (EPS), which have been studied to influence plant growth via various mechanisms. EPS-producing microorganisms have been found to have positive effects on plant health such as by facilitating nutrient entrapment in the soil, or by improving soil quality, especially by helping in mitigating various abiotic stress conditions. The various types of microbial polysaccharides allow for the compartmentalization of the microbial community enabling them to endure undressing stress conditions. With the growing population, there is a constant need for developing sustainable agriculture where we could use various PGPR to help the plant cope with various stress conditions and simultaneously enhance the crop yield. These polysaccharides have also found application in various sectors, especially in the biomedical fields, manifesting their potential to act as antitumor drugs, play a significant role in immune evasion, and reveal various therapeutic potentials. These constitute high levels of bioactive polysaccharides which possess a wide range of implementation starting from industrial applications to novel food applications. In this current review, we aim at presenting a comprehensive study of how these microbial extracellular polymeric substances influence agricultural productivity along with their other commercial applications.

Characterization of a biofilm-forming, amylase-producing, and heavy-metal-bioremediating strain Micrococcus sp. BirBP01 isolated from oligotrophic subsurface lateritic soil.

Lateritic soil is the reddish to brown-colored soil composed mainly of iron or aluminium oxides, hydroxides, or oxyhydroxides. Information on bacteria that inhabit this soil type, their ecological role, and metabolic potential are scarce. We have isolated and partially characterized a bacterial strain BirBP01 from a lead, calcium, and magnesium-rich, oligotrophic subsurface lateritic soil-sample collected from 12-feet deep horizon of a laterite mining pit in Birbhum district, India. The isolate is a biofilm-forming, Gram-positive bacterium having a sarcinae arrangement, mesophilic, slightly alkaliphilic, able to produce amylase, and resistant against multiple heavy-metals. BirBP01 has the ability to bioremediate 51% of Pb, 30% of Zn, and 22% of Cu through biosorption, possibly into the biofilm matrix. The bioremediating ability of the bacterium alleviated the inhibitory effect of heavy-metals on the germination of chickpea (Cicer arietinum L.) seeds. 16S rRNA gene-based phylogenetic analysis revealed that BirBP01 is a member of the genus Micrococcus. It showed more than 99% identity of the 16S rRNA gene sequence, and clustered within the same branch of the phylogenetic tree, with strains of M. yunnanensis, M. endophyticus, and M. luteus. The ability to produce amylase, and bioremediate heavy-metals signify that Micrococcus sp. BirBP01 could be potentially a good candidate for industrial applications, and to clean up heavy-metal contaminated sites.

Strategies to fortify the nutritional values of polished rice by implanting selective traits from brown rice: A nutrigenomics-based approach.

Whole-grain cereals are important components of a healthy diet. It reduces the risk of many deadly diseases like cardiovascular diseases, diabetes, cancer, etc. Brown rice is an example of whole grain food, which is highly nutritious due to the presence of various bioactive compounds (flavonoids, phenolics, vitamins, phytosterols, oils, etc.) associated with the rice bran layer of brown rice. White rice is devoid of the nutritious rice bran layer and thus lacks the bioactive compounds which are the major attractants of brown rice. Therefore, to confer health benefits to the public at large, the nutrigenomic potential of white rice may be improved by integrating the phytochemicals associated with the rice bran layer of brown rice into it via biofortification processes like conventional breeding, agronomic practices, metabolic engineering, CRISPR/Cas9 technology, and RNAi techniques. Thus, this review article focuses on improving the nutritional qualities of white/polished rice through biofortification processes, utilizing new breeding technologies (NBTs).

Epitaxial Single-Domain Cu-BTC Metal-Organic Framework Thin Films and Foils by Electrochemical Conversion of Cuprous Oxide.

Metal-organic frameworks (MOFs) are an important class of crystalline porous materials with extensive chemical and structural merits. However, the fabrication of MOF thin films oriented along all crystallographic axes to achieve well-aligned nanopores and nanochannels with uniform apertures remains a challenge. Here, we achieved highly crystalline single-domain MOF thin films with the [111] out-of-plane orientation by electrochemical conversion of cuprous oxide. Copper(II)-benzene-1,3,5-tricarboxylate, Cu3(BTC)2 (referred to as Cu-BTC), is a well-known metal-organic open framework material with a cubic crystal system. Epitaxial Cu-BTC(111) thin films were manufactured by electrochemical oxidation of Cu2O(111) films electrodeposited on single-crystal Au(111). The Cu-BTC(111) shows an in-plane antiparallel relationship with the precursor Cu2O(111) with a -0.91% coincidence site lattice mismatch. A plausible mechanism was proposed for the electrochemical conversion of Cu2O into Cu-BTC, indicating formation of intermediate CuO, growth of Cu-BTC islands, and termination with coalesce into a dense film with a limiting thickness of about 740 nm. The Faradaic efficiency for the electrochemical conversion was 63%. In addition, epitaxial Cu-BTC(111) foils were fabricated by epitaxial lift-off following the electrochemical etching of residual Cu2O underneath the Cu-BTC. It was also demonstrated that Cu-BTC(111) films with two in-plane domains and textured Cu-BTC(111) films can be achieved on a large scale using electrodeposited Au/Si and Au-coated glass as low-cost substrates.

Epitaxial Electrodeposition of Ordered Inorganic Materials.

ConspectusThe quality of technological materials generally improves as the crystallographic order is increased. This is particularly true in semiconductor materials, as evidenced by the huge impact that bulk single crystals of silicon have had on electronics. Another approach to producing highly ordered materials is the epitaxial growth of crystals on a single-crystal surface that determines their orientation. Epitaxy can be used to produce films and nanostructures of materials with a level of perfection that approaches that of single crystals. It may be used to produce materials that cannot be grown as large single crystals due to either economic or technical constraints. Epitaxial growth is typically limited to ultrahigh vacuum (UHV) techniques such as molecular beam epitaxy and other vapor deposition methods. In this Account, we will discuss the use of electrodeposition to produce epitaxial films of inorganic materials in aqueous solution under ambient conditions. In addition to lower capital costs than UHV deposition, electrodeposition offers additional levels of control due to solution additives that may adsorb on the surface, solution pH, and, especially, the applied overpotential. We show, for instance, that chiral morphologies of the achiral materials CuO and calcite can be produced by electrodepositing the materials in the presence of chiral agents such as tartaric acid.Inorganic compound materials are electrodeposited by an electrochemical-chemical mechanism in which solution precursors are electrochemically oxidized or reduced in the presence of molecules or ions that react with the redox product to form an insoluble species that deposits on the electrode surface. We present examples of reaction schemes for the electrodeposition of transparent hole conductors such as CuI and CuSCN, the magnetic material Fe3O4, oxygen evolution catalysts such as Co(OH)2, CoOOH, and Co3O4, and the n-type semiconducting oxide ZnO. These materials can all be electrodeposited as epitaxial films or nanostructures onto single-crystal surfaces. Examples of epitaxial growth are given for the growth of films of CuI(111) on Si(111) and nanowires of CuSCN(001) on Au(111). Both are large mismatch systems, and the epitaxy is explained by invoking coincidence site lattices in which x unit meshes of the film overlap with y unit meshes of the substrate.We also discuss the epitaxial lift-off of single-crystal-like foils of metals such as Au(111) and Cu(100) that can be used as flexible substrates for the epitaxial growth of semiconductors. The metals are grown on a Si wafer with a sacrificial SiOx interlayer that can be removed by chemical etching. The goal is to move beyond the planar structure of conventional Si-based chips to produce flexible electronic devices such as wearable solar cells, sensors, and flexible displays. A scheme is shown for the epitaxial lift-off of wafer-scale foils of the transparent hole conductor CuSCN.Finally, we offer some perspectives on possible future work in this area. One question we have not answered in our previous work is whether these epitaxial films and nanostructures can be grown with the level of perfection that is achieved in UHV. Another area that is ripe for exploration is the epitaxial electrodeposition of metal-organic framework materials from solution precursors.

Virtual screening and docking analysis of novel ligands for selective enhancement of tea (Camellia sinensis) flavonoids.

Flavour of tea is mainly contributed by a group of polyphenols - flavonoids. However, the content of flavonoid fluctuates seasonally and is found to be higher in the first flush of tea, when compared to the second flush. This disparity in the flavonoid content, and hence taste, incurs heavy economic losses to the tea plantation industry each harvest season. For our present study, four key product-specific enzymes (PAL, FNS, FLS and ANS) of the tea-specific flavonoid pathway were selected to perform molecular docking studies with specific virtually screened allosteric modulators. Results of docking analyses showed Naringenin, 2-Morpholin-4-ium-4-ylethanesulfonate, 6-C-Glucosylquercetin, 2-Oxoglutaric acid, 3,5,7,3',4'-pentahydroxyflavone to be capable of improving the spontaneity of the enzyme-substrate reactions in terms of docking score, RMSD values, and non-covalent interactions (H-bond,hydrophobic interaction, Π-stacking, salt bridge, etc.). Further, the evolutionary relationship of tea flavonoid pathway enzymes was constructed and compared with related taxa. The codon usage-based of tea flavonoid biosynthetic genes indicated the non-biasness of their nucleotide composition. Overall this study will provide a direction towards putative ligand-dependent enhancement of flavonoid content, irrespective of seasonal variation.

Flavonoid mediated selective cross-talk between plants and beneficial soil microbiome.

Plants generate a wide variety of organic components during their different growth phases. The majority of those compounds have been classified as primary and secondary metabolites. Secondary metabolites are essential in plants' adaptation to new changing environments and in managing several biotic and abiotic stress. It also invests some of its photosynthesized carbon as secondary metabolites to establish a mutual relationship with soil microorganisms in that specific niche. As soil harbors both pathogenic and beneficial microorganisms, it is essential to identify some specific metabolites that can discriminate beneficial and pathogenic ones. Thus, a detailed understanding of metabolite's architectures that interact with beneficial microorganisms could open a new horizon of ecology and agricultural research. Flavonoids are used as classic examples of secondary metabolites in this study to demonstrate recent developments in understanding and realizing how these valuable metabolites can be controlled at different levels. Most of the research was focused on plant flavonoids, which shield the host plant against competitors or predators, as well as having other ecological implications. Thus, in the present review, our goal is to cover a wide range of functional and signalling activities of secondary metabolites especially, flavonoids mediated selective cross-talk between plant and its beneficial soil microbiome. Here, we have summarized recent advances in understanding the interactions between plant species and their rhizosphere microbiomes through root exudates (flavonoids), with a focus on how these exudates facilitate rhizospheric associations. Supplementary Information: The online version contains supplementary material available at 10.1007/s11101-022-09806-3.

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

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.

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

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.

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

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 Pb2+ 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 Pb2+ , thus confirming algal bio-accumulation abilities. Sensitivity assay demonstrated that 500 and 400 ppm of Pb2+ 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 Pb2+ , respectively. The particulate analysis of Pb2+ 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 Pb2+ 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 Pb2+ stress. S. acutus strain showed higher tolerance and higher bioremoval capacity than C. pyrenoidosa. However, both the species can be exploited for biosorption of Pb2+ from aquatic streams as an alternative way for low cost Pb2+ recovery systems.

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

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 Cd2+ 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 Cd2+ treatment, respectively. During bioremoval studies, C. pyrenoidosa and S. acutus have shown 45.45% and 57.14% Cd2+ removal of Cd2+ 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 Cd2+ contaminated water bodies as they serve the dual purpose by Cd remediation and algal biomass production.

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

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.

Ultrasensitive NOX Detection in Simulated Exhaled Air: Enhanced Sensing via Alumina Modification of In-Situ Grown WO3 Nanoblocks.

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, WO3 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-Al2 O3 ), by electrodeposition, resulted in the selective and ultrasensitive detection of NOX 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 WO3 . Improved surface area and porosity is presented by porous alumina in the modified WO3 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 WO3 and Al2 O3 -modified WO3 . The higher sensitivity for NOX gas in case of γ-Al2 O3 -modified WO3 based devices, as compared to bare WO3 -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.

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.

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-1 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.

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.

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-1, Aluminium≈1800mgkg-1, Lead≈1800mgkg-1), pH (6-10), PGP attributes (indole - 1.05-3.15µgml-1, ammonia - 0.13-19.95mmolml-1, nitrite - 0.07-0.26mmolml-1) 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.

Efficient Energy Harvesting in SnO2-Based Dye-Sensitized Solar Cells Utilizing Nano-Amassed Mesoporous Zinc Oxide Hollow Microspheres as Synergy Boosters.

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 SnO2 nanoparticles (NPs), i.e., SnO2 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 SnO2 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 (τe) and a higher value of R ct2 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.

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

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.

Cs -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.

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 D1 was synthesized using the Pd-catalyzed Suzuki cross-coupling and Knoevenagel condensation reactions. On the basis of the optical, electrochemical, and computational studies, dye D1 showed a better electronic interaction between the donor and acceptor moieties. As-synthesized C 2 symmetric triphenylamine-linked bisthiazole-based organic dye D1 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 D1 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 (J sc) of 13.60 mA cm-2, which results in a power conversion efficiency (PCE) of 4.94% under AM 1.5 irradiation (100 mW cm-2). The high PCE value is the result of proficient electron injection from E LUMO of dye D1 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.

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

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 Ag+in vitro endophytic bacteria infected rice root tissue. Experimental results have been substantiated by theoretical DFT calculations.

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

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 (SiO2 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% SiO2 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 SiO2 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-/I3- redox shuttle in the case of the composite photoanode. The higher recombination resistance (Rct) in the case of a 1 wt% composite indicates that the SiO2 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.