Paper-Based Simplified Visual Detection of Cry2Ab Insecticide from Transgenic Cottonseed Samples Using Integrated Quantum Dots-IgY Antibodies.

In the present study, an easy to use field-deployable methodology was developed for onsite detection of pesticidal crystal protein Cry2Ab from transgenic cotton crops to reduce seed adulteration. Anti Cry2Ab IgG and IgY antibodies were developed against recombinant Cry2Ab protein in New Zealand white rabbits and in white leg horn chickens, respectively. Carboxyl-functionalized CdTe quantum dots (QDs) were used as revealing probes, and nitrocellulose paper was used as an assay matrix. Recombinant Cry2Ab was generated in the lab and used for immunization of chicken and rabbits. After successful immunization and attaining the desired titer values (1:32 000 for IgY and 1:64 000 for IgG), eggs and hyperimmune sera were collected. Anti Cry2Ab IgY was purified as per the standardized protocols, and anti Cry2Ab IgG was purified using protein A affinity chromatography. Sensitivity of the generated antibodies was examined using indirect ELISA methods against recombinant Cr2Ab protein. Specificity evaluation was carried out against other Cry proteins including Cry2Ab, Cry4b, Cry4a, Cry1Ec, and Cry1Ac. Functionalized CdTe QDs were characterized for structure and shape as well as fluorescence properties using standard laboratory techniques. A field-deployable paper-based detection methodology was developed where IgG acted as the capturing antibody and IgY-linked CdTe QDs were used as revealing probes. The limit of detection (LOD) and quantification (LOQ) were found to be 2.91 ng/mL and 9.71 ng/mL, respectively. The effect of matrix interference was assessed on the different plant crude extracts of cottonseed materials.

Pb2+ and Cd2+ recovery from water using residual tea waste and SiO2@TW nanocomposites.

This work reports the fabrication of SiO2@TW nanocomposites and their application for Pb2+ and Cd2+ ions sequestration from simulated water. Residual tea waste has also been used for metal ions sequestration to compare the potential of SiO2@TW nanocomposites. The SEM, TEM, BET, FTIR and EDX techniques were employed for the characterization of SiO2@TW nanocomposites and residual tea waste. Particle sizes of SiO2@TW nanocomposites was in the range of 6.8-12 nm. The experiments were carried out in batch mode to explore the effect of various operating parameters on the sequestration of Pb2+ and Cd2+ ions from water. The experimental data was subjected to various thermodynamic, kinetic and isothermic models. According to Langmuir model, the maximum adsorption efficiency of the SiO2@TW nanocomposites was 153 mg/g for Pb2+ and 222 mg/g for Cd2+ but maximum adsorption efficiency of residual tea waste for Pb2+ was 125 mg/g and for Cd2+ was 142.9 mg/g. This study suggested that due to the presence of active sites SiO2@TW nanocomposites has greater potential for metal sequestration than residual tea waste.

Amelioration of chromium and heat stresses in Sorghum bicolor by Cr6+ reducing-thermotolerant plant growth promoting bacteria.

Climatic factors particularly increased atmospheric temperature (IAT) greatly alters plant microbe and heavy metal interactions and subsequently reduces plant growth and phytoremediation efficiency. The aim of the study was to assess the effects of inoculation of chromium reducing-thermotolerant plant growth promoting bacteria (CRT-PGPB) on plant growth, physiological responses and chromium (Cr) uptake by Sorghum bicolor under IAT condition. Three potential CRT-PGPB strains were isolated from Cr contaminated sites and identified as Bacillus cereus TCR17, Providencia rettgeri TCR21 and Myroides odoratimimus TCR22 through molecular characterization. These strains displayed the potential to reduce Cr6+ to Cr3+, produce siderophores, indole-3-acetic acid and solubilize phosphate. Inoculation of S. bicolor with CRT-PGPB increased plant growth, antioxidant status (superoxide dismutase, catalase and ascorbate peroxidase) and decreased proline and malondialdehyde contents in plants under Cr, IAT and Cr + IAT stress indicate that PGPB helped plants to reduce stress induced oxidative damage. Irrespective of IAT stress, inoculation of CRT-PGPB decreased the accumulation of Cr in plants compared with un-inoculated control suggest that CRT-PGPB might have the potential to improve phytostabilization process in Cr contaminated soils. Furthermore, gene expression studies confirmed that inoculation of TCR21 down-regulated the expression of proline synthesis gene (p5cs1) and up-regulated the expression of antioxidant related genes (sod, apx1 and cat) and stress tolerance genes (sHsp). Our results showed that CRT-PGPB exhibiting potential to tolerate Cr, temperature, produce plant beneficial metabolites and reduce Cr6+ to Cr3+, can be exploited as potential inoculants for improving plant growth and phytoremediation process in Cr contaminated soil under IAT condition.

Chitosan as an environment friendly biomaterial - a review on recent modifications and applications.

Amongst the natural polymers, chitin is the second most abundant, present mainly in fungi and exoskeleton of crustaceans. It forms a major part of the seafood waste as compiled and presented in this review and is de-acetylated to produce chitosan. Structure and properties of chitosan have been described. Biocompatible and biodegradable characteristics of chitosan have been well studied. In addition to the environmental sustainability associated with its use, the malleability of chitosan due to its reactive amino and hydroxyl groups, adds to its wide repertoire in usage through various modifications. Recent publications of chitosan and derivatives have been classified into its various applications in food, pharmaceutical, biotechnology, medical, textile, paper, agriculture and environmental applications. The abundance of chitosan and diversity in modifications can be effectively utilized in various applications leading to environmental friendly solutions as highlighted in this review.

Applications of Fe3O4@AC nanoparticles for dye removal from simulated wastewater.

This study deals with the removal of cationic dyes from the simulated wastewater using Fe3O4 nanoparticles loaded activated carbon. Fe3O4@AC nanoparticles were synthesised using co-precipitation methods. The Fe3O4@AC nanoparticles (nps) were characterised using different techniques and data revealed that the synthesised nanoparticles were 6-16 nm in diameter. pHpzc of Fe3O4@AC nanoparticles was 7.8. BET surface area of Fe3O4@AC nps was found to be 129.6 m2/g by single point method and 1061.9 m2/g by multipoint method. Adsorption experiments were performed to optimize the effect of process conditions such as pH of solution, nanoparticles dose, temperature, concentration of dye and contact time on contaminant removal. The maximum uptake capacity of Fe3O4@AC was found to be 138 and 166.6 mg/g for methylene blue and brilliant green dyes, respectively. In order to assess dye adsorption behaviour, adsorption isotherm models viz., Langmuir, Freundlich and Temkin were applied to the data. Langmuir isotherm best fitted [R2 = 0.993 (MB) and R2 = 0.920 (BG)] to the experimental data of both the dyes. Further, Pseudo-second order rate equation fitted better to the experimental data. Reuse potential of the nanoparticles was also investigated for the removal of both the dyes and it is inferred from the data that the synthesised nanoadsorbent has promising reuse potential, therefore can be used for several cycles.

Isolation and characterization of water-deficit stress-responsive α-expansin 1 (EXPA1) gene from Saccharum complex.

In this study, full-length (1282-1330 bp) α-expansin 1 (EXPA1) gene from three different accessions belonging to Saccharum complex (Saccharum officinarum-SoEXPA1, Erianthus arundinaceus-EaEXPA1, and Saccharum spp. hybrid-ShEXPA1) was isolated using RAGE technique and characterized. The intronic and coding regions of isolated expansin genes ranged between 526-568 and 756-762 bp, respectively. An open reading frame encoding a polypeptide of 252 amino acids was obtained from S. officinarum and commercial sugarcane hybrid, whereas 254 amino acids were obtained in E. arundinaceus, a wild relative of Saccharum. Bioinformatics analysis of deduced protein revealed the presence of specific signature sequences and conserved amino acid residues crucial for the functioning of the protein. The predicted physicochemical characterization showed that the protein is stable in nature with instability index (II) value less than 40 and also clearly shown the dominance of random coil in the protein structure. Phylogenetic analysis revealed high conservation of EXPA1 among Saccharum complex and related crop species, Sorghum bicolor and Zea mays. The docking study of EXPA1 protein showed the interaction with xylose, which is present in xyloglucan of plant cell wall, elucidated the role of the expansin proteins in plant cell wall modification. This was further supported by the subcellular localization experiment in which it is clearly seen that the expansin protein localizes in the cell wall. Relative expression analysis of EXPA1 gene in Saccharum complex during drought stress showed high expression of the EaEXPA1 in comparison with SoEXPA1 and ShEXPA1 indicating possible role of EaEXPA1 in increased water-deficit stress tolerance in E. arundinaceus. These results suggest the potential use of EXPA1 for increasing the water-deficient stress tolerance levels in crop plants.

Photoinduced holes transfer based visual determination of dopamine in human serum.

A simple unexplored strategy was followed to construct ratiometric fluorescence-based sensing system for the detection of dopamine (DA) in human serum. Ratiometric fluorescence system was constructed through bonding energy transfer (TBET) by conjugating carboxyl functionalized CdTe quantum dots (QDs) and amine-capped Carbon quantum dots (CQDs). The photophysical properties of sensing system were characterized by standard methods. Photoluminescence (PL) of sensing system under excitonic wavelength (350 nm) depends on dual emission at 440 and 595 nm that corresponds to CQDs and CdTe QDs respectively. The developed sensing system was utilized for visual determination of DA, an unquenched blue fluorescence of CQDs in ratiometric system reveals the visual color differentiation for DA binding with CdTe QDs among the possible interferences (Alanine, Glycine, Glucose, Sucrose, Urea and Ascorbic acid). The limit of detection (LOD) and quantification (LOQ) was calculated as 8.1 and 27.2 nm respectively by using regression analysis. Photoinduced holes transfer (PHT) might have attributed the possible sensing mechanism for DA that quench the photoluminescence sequentially to enhance the sensing performance of QDs. The matrix interferences and reliability of the developed sensing platform were evaluated by testing DA spiked human serum and the sensing response was found to be field deployable.

Bio-production of novel water-soluble yellow pigment from Aspergillus sp. and exploring its sustainable textile applications.

In the present study, 40 pigment-producing microbes were isolated from various soil sources. Among these, a novel water-soluble yellow pigment-producing fungal isolate (MBYP1) was identified as Aspergillus sp. through ITS gene sequencing. The maximum pigment yield (UA430nm, 12.45 ± 0.5 g/l) was obtained when strain MBYP1 was cultured under optimum conditions (28 °C and pH 5.5 under static condition). Subsequently, the pigment was purified through gel chromatography and high-performance liquid chromatography (HPLC). Characterization of purified pigment through UV-Vis and liquid chromatography-mass spectrometry (LC-MS) reveal maximum absorbance at 430 nm and molecular mass of 301 m/z, respectively. Further, the pigment exhibited a maximum dyeing capacity of up to 80% irrespective of mordant. Toxicity evaluation of purified pigment with zebra fish model system reported an IC50 value of 710 µg/mL. Pigment antioxidant ability was established by DPPH (35.7 µg/mL) and phosphomolybdenum assay (226.61 mg/g) thus ascertaining improvised light fastness of dyed fabric. Moreover, lack of antimicrobial activity (up to 40 µg/mL) improves pigment bio-degradability. In collective, the novel yellow pigment from Aspergillus sp. MBYP1 strain was found to be an eco-friendly alternative to synthetic dye for potential applications in textile industries.

Biological approaches to tackle heavy metal pollution: A survey of literature.

Pollution by heavy metals has been identified as a global threat since the inception of industrial revolution. Heavy metal contamination induces serious health and environmental hazards due to its toxic nature. Remediation of heavy metals by conventional methods is uneconomical and generates a large quantity of secondary wastes. On the other hand, biological agents such as plants, microorganisms etc. offer easy and eco-friendly ways for metal removal; hence, considered as efficient and alternative tools for metal removal. Bioremediation involves adsorption, reduction or removal of contaminants from the environment through biological resources (both microorganisms and plants). The heavy metal remediation properties of microorganisms stem from their self defense mechanisms such as enzyme secretion, cellular morphological changes etc. These defence mechanisms comprise the active involvement of microbial enzymes such as oxidoreductases, oxygenases etc, which influence the rates of bioremediation. Further, immobilization techniques are improving the practice at industrial scales. This article summarizes the various strategies inherent in the biological sorption and remediation of heavy metals.

Development and evaluation of an IgY based silica matrix immunoassay platform for rapid onsite SEB detection.

The present study involves immunoassay platform development based on a surface functionalized silica matrix for rapid onsite detection of Staphylococcal enterotoxin B (SEB). Silica matrix functionalization as well as the immunoassay parameters was experimentally designed and optimized through response surface methodology (RSM). Silica surface functionalization was carried out with hydrofluoric acid (HF), ammonia, 3-aminopropyl triethoxysilane (APTES) and glutaraldehyde (GA). The RSM optimized matrix functionalization parameters for HF, ammonia, APTES and GA were determined to be 10%, 40%, 20% and 10% (V/V), respectively. Antibodies for the study were generated against recombinant SEB toxin in rabbit (anti-SEB IgG) and chicken (anti-SEB IgY). Subsequently, antibodies were immobilized on the functionalized silica matrix and were further characterized by SEM and contact angle measurements to elucidate the surface uniformity and degree of hydrophilicity. The immunoassay platform was developed with anti-SEB IgG (capturing agent) and anti-SEB IgY (revealing partner). The limit of detection (LOD) of the developed platform was determined to be 0.005 µg mL-1 and no cross-reactivity with similar toxins was observed. Upon co-evaluation with a standard ELISA kit (Chondrex, Inc) against various field isolates, the platform was found to be on par and reliable. In conclusion, the developed method may find better utility in onsite detection of SEB from resource-poor settings.

Gold Nanoparticles Supported on Magnesium Oxide Nanorods for Oxidation of Alcohols.

Gold nanoparticles supported on magnesium oxide nanorods (Au-MgO) have been synthesised by a solution based chemical reduction method. Au-MgO nanorods were found to be an efficient heterogeneous catalyst for oxidation of alcohols with hydrogen peroxide in aqueous medium at room temperature. To find out the best reaction conditions for oxidation, optimization of catalyst quantity, solvent, mole equivalence of hydrogen peroxide were carried out. The scope of the reaction was extended to several aromatic and aliphatic alcohols, product yields were quantified by gas chromatography (GC) and GC/mass spectroscopy. Heterogeneity and reusability tests were performed. The use of water as a solvent and hydrogen peroxide as co-catalyst at room temperature makes the reaction interesting from sustainable development point of view.

Effect of sintering temperature on structural and optical properties of indium(III) oxide nanoparticles prepared with Triton X-100 by hydrothermal method.

Indium(III) hydroxide (In(OH)3) powders prepared via Triton X-100 mediated hydrothermal method was sintered at different temperatures (400, 500 and 600°C) to yield indium(III) oxide nanoparticles (In2O3 NPs). Thermal studies of In(OH)3 confirmed complete conversion to In2O3 around 400°C. Powder X-ray diffraction (XRD) pattern of sintered In2O3 nanoparticles revealed the formation of phase pure cubic In2O3. The crystallite size of In2O3 NPs was increased from 12 to 26nm upon increasing the sintering temperature from 400°C to 600°C, while the percentage crystallinity was increased up to 90% after sintering at 600°C. A red shift in the band gap energy was observed with increasing sintering temperature due to the larger size of sintered In2O3 NPs. Room temperature photoluminescence spectra of the indium oxide nanoparticles showed both near band and excitonic emission of In2O3 due to oxygen vacancies.

Cadmium(II) sorption and desorption in a fixed bed column using sunflower waste carbon calcium-alginate beads.

The present study reports the use of sunflower waste carbon calcium-alginate beads (SWC-CAB) for cadmium removal from wastewater in continuous flow fixed bed columns. The experiments were conducted as a function of bed height, flow rate and initial Cd(II) concentration. The maximum biosorption capacity (23.6 mg/g) was attained at 30 cm bed height, 1.0 mL/min flow rate and 10 mg/L initial Cd(II) concentration. The Bohart-Adams model constants (N0 and K) were 7.7 mg/L and 1×10(-4) L/mgh with 0.999 R2 value at 50% breakthrough time. The column regeneration efficiency after third cycle was 58.6% for cadmium.

Investigation of Cr(VI) adsorption onto chemically treated Helianthus annuus: optimization using response surface methodology.

In the present study, chemically treated Helianthus annuus flowers (SHC) were used to optimize the removal efficiency for Cr(VI) by applying Response Surface Methodological approach. The surface structure of SHC was analyzed by Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Analysis (EDX). Batch mode experiments were also carried out to assess the adsorption equilibrium in aqueous solution. The adsorption capacity (qe) was found to be 7.2 mg/g. The effect of three parameters, that is pH of the solution (2.0-7.0), initial concentration (10-70 mg/L) and adsorbent dose (0.05-0.5 g/100 mL) was studied for the removal of Cr(VI) by SHC. Box-Behnken model was used as an experimental design. The optimum pH, adsorbent dose and initial Cr(VI) concentration were found to be 2.0, 5.0 g/L and 40 mg/L, respectively. Under these conditions, removal efficiency of Cr(VI) was found to be 90.8%.

Equilibrium and kinetic studies for sequestration of Cr(VI) from simulated wastewater using sunflower waste biomass.

In the present work, potential of sunflower head (BSH) [an agricultural waste biomass] to remove Cr(VI) from simulated wastewater has been evaluated under different process conditions such as pH, metal concentration, adsorbent dose and contact time. A contact time of 120 min and pH 2.0 were found to be optimum. Chromium removal decreased from 90.0 to 45.2% as its concentration increased from 10 to 70 mg/L. The Cr(VI) removal increased from 31.4 to 52.4% as adsorbent dose increased from 4.0 to 20.0 g/L using a test solution having 100mg/L Cr(VI) concentration. Adsorption isotherms were employed to evaluate the maximum adsorption capacity. Adsorption data fitted well to Langmuir isotherm and pseudo-second order model as indicated by high values of correlation coefficient (0.9882 and 0.999) respectively. The adsorption capacity calculated from Langmuir isotherm was 8.177 mg/g.

Chromium(VI) removal from aqueous system using Helianthus annuus (sunflower) stem waste.

The objective of this study was to investigate the Cr(VI) removal efficiency of sunflower waste from aqueous system under different process conditions. Two adsorbents were prepared by pre-treating the sunflower stem waste. One adsorbent was prepared by boiling it and second adsorbent was prepared by treating it with formaldehyde. Batch mode experiments were carried out as a function of solution pH, adsorbent dosage, Cr(VI) concentration and contact time. FT-IR spectra and SEMs of the adsorbents were recorded to explore the number and position of functional groups available for the binding of Cr(VI) ions and morphology of the studied adsorbents. The removal of chromium was dependent on the physico-chemical characteristics of the adsorbent, adsorbate concentration and other studied process parameters. Maximum metal removal was observed at pH 2.0. The efficiencies of boiled sunflower stem absorbent and formaldehyde-treated sunflower stem absorbent for the removal of Cr(VI) were 81.7 and 76.5%, respectively for dilute solutions at 4.0g/L adsorbent dose. The applicability of Langmuir, Freundlich and Dubinin-Radushkevich isotherms was also tested. The results revealed that the hexavalent chromium is considerably adsorbed on sunflower stem and it could be an economical method for the removal of hexavalent chromium from aqueous systems.

Adsorption of Pb(II) and Cd(II) metal ions from aqueous solutions by mustard husk.

The adsorption of Pb(II) and Cd(II) metal ions on mustard husk has been found to be concentration, pH, contact time, adsorbent dose and temperature dependent. The adsorption parameters were determined using Langmuir and Freundlich isotherm models. The adsorption isotherm studies clearly indicated that the adsorptive behavior of Pb(II) and Cd(II) metal ions on mustard husk satisfies not only the Langmuir assumptions but also the Freundlich assumptions, i.e. multilayer formation on the surface of the adsorbent with an exponential distribution of site energy. Ion exchange and surface complexation are the major adsorption mechanisms involved. The applicability of Lagergren kinetic model has also been investigated. Thermodynamic constant (k(ad)), free energy change (DeltaG), enthalpy change (DeltaH) and entropy change (DeltaS) were calculated for predicting the nature of adsorption. The results indicate the potential application of this method for effluent treatment in industries and also provide strong evidence to support the adsorption mechanism proposed.

Sorption of lead, mercury and cadmium ions in multi-component system using carbon aerogel as adsorbent.

In the present study, adsorption of three metal ions Pb(II), Hg(II) and Cd(II) on carbon aerogel a new form of activated carbon has been investigated in mono- and multi-component (binary and tertiary) system. Batch experiments were also carried out for mono- and multi-component systems with varying metal ion concentration (mg/l) to investigate the competitive adsorption characteristics. Many adsorbents have been studied for their adsorption properties pertaining to mono-component solutions of metal ions. However, to treat wastewater with new materials, their performance needs to be ascertained in multi-component system. The scanning electron micrographs (SEM) and EDAX spectrum of carbon aerogel surfaces before and after the adsorbent was equilibrated with the metal ion solution clearly establishes the presence of the metal ions and some surface modifications can be observed on the carbon aerogel particles adsorption with (i) surface chemistry of the pellets on the surface of carbon aerogel and (ii) inside layers of the carbon aerogel. Applicability of the isotherm models namely Freundlich and Langmuir to predict the equilibrium uptake of Pb(II), Hg(II) and Cd(II) in mono-component, binary and tertiary system has also been tested. Langmuir and Freundlich models are found to generally represent the experimental though but not consistently.

Adsorptive removal of heavy metals from aqueous solution by treated sawdust (Acacia arabica).

The removal of Cr(VI), Pb(II), Hg(II) and Cu(II), by treated sawdust has been found to be concentration, pH, contact time, adsorbent dose and temperature dependent. The adsorption parameters were determined using both Langmuir and Freundlich isotherm models. Adsorption capacity for treated sawdust, i.e. Cr(VI) (111.61 mg/g), Pb(II) (52.38 mg/g), Hg(II) (20.62 mg/g), and Cu(II) (5.64 mg/g), respectively. Surface complexation and ion exchange are the major removal mechanisms involved. The adsorption isotherm studies clearly indicated that the adsorptive behaviour of metal ions on treated sawdust satisfies not only the Langmuir assumptions but also the Freundlich assumptions. The applicability of Lagergren kinetic model has also been investigated. The adsorption follows first-order kinetics. Thermodynamic constant (k(ad)), standard free energy (DeltaG degrees ), enthalpy (DeltaH degrees ) and entropy (DeltaS degrees ) were calculated for predicting the nature of adsorption. The percentage adsorption increases with pH to attain a maximum at pH 6 and thereafter it decreases with further increase in pH. The results indicate the potential application of this method for effluent treatment in industries and also provide strong evidence to support the adsorption mechanism proposed.

Utilization of modified silk cotton hull waste as an adsorbent for the removal of textile dye (reactive blue MR) from aqueous solution.

Carbon prepared from silk cotton hull was used to remove a textile dye (reactive blue MR) from aqueous solution by an adsorption technique under varying conditions of agitation time, dye concentration, adsorbent dose and pH. Adsorption depended on solution pH, dye concentration, carbon concentration and contact time. Equilibrium was attained with in 60 min. Adsorption followed both Langmuir and Freundlich isotherm models. The adsorption capacity was found to be 12.9 mg/g at an initial pH of 2+/-0.2 for the particle size of 125-250 microm at room temperature (30+/-2 degrees C).