First report of betalain production from endolichenic Bacillus sp. LDAB-1 from Dirinaria aegilita: Insights from novel quantification methodology of image processing.

Pigments are widely used in food supplements envisaging attractive colors along with health benefits. The desired advancements in the nutraceutical and antioxidant properties of pigments utilized in food products necessitate the search for novel additives. The present study is the first in the field to report the pigment-producing endolichenic bacteria, Bacillus sp. LDAB-1 from Dirinaria aegilita. Morphological, biochemical, and molecular characterization of the bacterium emphasizes that ideal pigment production occurs when utilizing sucrose and sodium nitrate. The pigment was salted out and dialyzed for further qualitative characterization using ultraviolet-visible, fluorescence, and Fourier transform infrared spectra and the results corroborated the presence of betalains. The antioxidant activity of betalain is closer to the efficiency of α-tocopherol, which confers the pigment properties for antioxidant and nutraceutical significance. An optimal methodology for pigment affirmation is an issue when using an alternative methodology. Hence, the present assessment employs a comparative analysis of findings from both a spectrophotometric method and image processing technology encompassing RGB, CMYK, YCbCr, and L*a*b* color space models. Amongst these, the L*a*b* model potentially provides an effective modality for determining the pigment concentration. Bland-Altman plot analysis indicates similar consistency levels in betalain quantification by both methods at 95% confidence intervals, affirming the integrity and consistency of color image processing technology. Consequently, the present study represents novelty and innovativeness in reporting endolichenic Bacillus sp. LDAB-1 from D. aegilita and a rational image optimization protocol for pigment elucidation characteristics.

Unveiling the therapeutic potential of thymol from Nigella sativa L. seed: selective anticancer action against human breast cancer cells (MCF-7) through down-regulation of Cyclin D1 and proliferative cell nuclear antigen (PCNA) expressions.

BACKGROUND: Breast adenocarcinoma cells (MCF-7) are characterized by the overexpression of apoptotic marker genes and proliferative cell nuclear antigen (PCNA), which promote cancer cell proliferation. Thymol, derived from Nigella sativa (NS), has been investigated for its potential anti-proliferative and anticancer properties, especially its ability to suppress Cyclin D1 and PCNA expression, which are crucial in the proliferation of cancer cells. METHODS: The cytotoxicity of thymol on MCF-7 cells was assessed using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) release methods. Thymol was tested at increasing concentrations (0-1000 µM) to evaluate its impact on MCF-7 cell growth. Additionally, Cyclin D1 and PCNA gene expression in thymol-treated and vehicle control groups of MCF-7 were quantified using real-time Polymerase Chain Reaction (RT-qPCR). Protein-ligand interactions were also investigated using the CB-Dock2 server. RESULTS: Thymol significantly inhibited MCF-7 cell growth, with a 50% inhibition observed at 200 µM. The gene expression of Cyclin D1 and PCNA was down-regulated in the thymol-treated group relative to the vehicle control. The experimental results were verified through protein-ligand interaction investigations. CONCLUSIONS: Thymol, extracted from NS, demonstrated specific cytotoxic effects on MCF-7 cells by suppressing the expression of Cyclin D1 and PCNA, suggesting its potential as an effective drug for MCF-7. However, additional in vivo research is required to ascertain its efficacy and safety in medical applications.

Biosynthesis of Nanoparticles from Various Biological Sources and Its Biomedical Applications.

In the last few decades, the broad scope of nanomedicine has played an important role in the global healthcare industry. Biological acquisition methods to obtain nanoparticles (NPs) offer a low-cost, non-toxic, and environmentally friendly approach. This review shows recent data about several methods for procuring nanoparticles and an exhaustive elucidation of biological agents such as plants, algae, bacteria, fungi, actinomycete, and yeast. When compared to the physical, chemical, and biological approaches for obtaining nanoparticles, the biological approach has significant advantages such as non-toxicity and environmental friendliness, which support their significant use in therapeutic applications. The bio-mediated, procured nanoparticles not only help researchers but also manipulate particles to provide health and safety. In addition, we examined the significant biomedical applications of nanoparticles, such as antibacterial, antifungal, antiviral, anti-inflammatory, antidiabetic, antioxidant, and other medical applications. This review highlights the findings of current research on the bio-mediated acquisition of novel NPs and scrutinizes the various methods proposed to describe them. The bio-mediated synthesis of NPs from plant extracts has several advantages, including bioavailability, environmental friendliness, and low cost. Researchers have sequenced the analysis of the biochemical mechanisms and enzyme reactions of bio-mediated acquisition as well as the determination of the bioactive compounds mediated by nanoparticle acquisition. This review is primarily concerned with collating research from researchers from a variety of disciplines that frequently provides new clarifications to serious problems.

CTAB enabled microwave-hydrothermal assisted mesoporous Zn-doped hydroxyapatite nanorods synthesis using bio-waste Nodipecten nodosus scallop for biomedical implant applications.

In biomedical exploration, the predominant characteristic is synthesizing and fabricating multifunctional nanostructure with intensified biocompatibility and excellent antibacterial applications to avoid post-surgical implant failure. The objective of the current study is to examine ideal mesoporous zinc-doped hydroxyapatite (HAp) for future use in the field of biomedical research. In the present investigation, we synthesized mesoporous Zn-doped HAp nanorods with varied mole concentrations using a profound microwave hydrothermal method utilizing bio-waste Nodipecten nodosus scallop as a calcium source and CTAB as an organic modifier. Bio-waste Nodipecten nodosus scallop is a widely available cheap calcium precursor which is converted into pure and zinc-doped hydroxyapatite nanorods with the help of the microwave hydrothermal method. Different analytical techniques like spectroscopy and electron microscopy were employed to evaluate and precisely characterize the structural and morphological characteristics in synthesized pure and mesoporous Zn-doped HAp nanorods. CTAB and microwave hydrothermal methods successfully create mesoporous Zn-doped hydroxyapatite nanorods with different sizes and morphology. Mesoporous Zinc-doped HAp nanorods show excellent antibacterial activity against Klebsiella pneumoniae (MTCC 7407) and Bacillus subtilis (MTCC 1133), compared to other nanorods. ZnHAp-3 shows notable excellent results of antibacterial effect towards K. pneumoniae and B. subtilis, by exhibiting 12.36 ± 0.12 and 13.12 ± 0.16 mm zone of inhibition. Furthermore, ZnHAp-1 shows the lower zone of inhibition, while the ZnHAp-3 sample shows the highest zone of inhibition. A foremost study performed was toxicity assays to validate safe attributes of mesoporous zinc-doped HAp intensified with the proliferation function of the zebrafish model. The results reveal the non-toxic behavior of pure and mesoporous zinc-doped HAp samples. Thus, our studies provide evidence for the synthesis technique for the mesoporous zinc-doped HAp nanorods using a novel CTAB-enabled microwave hydrothermal method utilizing bio-waste Nodipecten nodosus scallop as a calcium source will be alternative affordable biocidal antibacterial materials for controlling post-surgical implant failures.

Carbon Quantum Dots' Synthesis with a Strong Chemical Claw for Five Transition Metal Sensing in the Irving-Williams Series.

Carbon quantum dots (CQDs) are an excellent eco-friendly fluorescence material, ideal for various ecological testing systems. Herein, we establish uniform microwave synthesis of the group of carbon quantum dots with specific functionalization of ethylenediamine, diethylenetriamine, and three types of Trilon (A, B and C) with chelate claws -C-NH3. CQDs' properties were studied and applied in order to sense metal cations in an aquatic environment. The results provide the determination of the fluorescence quench in dots by pollutant salts, which dissociate into double-charged ions. In particular, the chemical interactions with CQDs' surface in the Irving-Williams series (IWs) via functionalization of the negatively charged surface were ascribed. CQD-En and CQD-Dien demonstrated linear fluorescence quenching in high metal cation concentrations. Further, the formation of claws from Trilon A, Trilon B, and C effectively caught the copper and nickel cations from the solution due to the complexation on CQDs' surface. Moreover, CQD-Trilon C presented chelating properties of the surface and detected five cations (Cu2+, Ni2+, Ca2+, Mg2+, Zn2+) from 0.5 mg/mL to 1 × 10-7 mg/mL in the Irving-William's series. Dependence was mathematically attributed as an equation (ML regression model) based on the constant of complex formation. The reliability of the data was 0.993 for the training database.

Citric Acid-Mediated Microwave-Hydrothermal Synthesis of Mesoporous F-Doped HAp Nanorods from Bio-Waste for Biocidal Implant Applications.

In this current research, mesoporous nano-hydroxyapatite (HAp) and F-doped hydroxyapatite (FHAp) were effectively obtained through a citric acid-enabled microwave hydrothermal approach. Citric acid was used as a chelating and modifying agent for tuning the structure and porosity of the HAp structure. This is the first report to use citric acid as a modifier for producing mesoporous nano HAp and F-doped FHAp. The obtained samples were characterized by different analyses. The XRD data revealed that F is incorporated well into the HAp crystal structure. The crystallinity of HAp samples was improved and the unit cell volume was lowered with fluorine incorporation. Transmission electron microscopy (TEM) images of the obtained samples revealed that a nano rod-like shape was obtained. The mesoporous structures of the produced HAp samples were confirmed by Brunauer-Emmett-Teller (BET) analysis. In vivo studies performed using zebrafish and C. elegans prove the non-toxic behavior of the synthesized F doped HAp samples. The obtained samples are also analyzed for antimicrobial activity using Gram-negative and Gram-positive bacteria, which are majorly involved in implant failure. The F doped samples revealed excellent bactericidal activity. Hence, this study confirms that the non-toxic and excellent antibacterial mesoporous F doped HAp can be a useful candidate for biocidal implant application.

Mesoporous Mn-doped hydroxyapatite nanorods obtained via pyridinium chloride enabled microwave-assisted synthesis by utilizing Donax variabilis seashells for implant applications.

Manganese-doped mesoporous hydroxyapatite (MnHAp) nanorods, a bio-apatite were synthesized via pyridinium chloride mediated microwave approach using bio-waste Donax variabilis seashells to treat orthopedic infections. This is the first report on using pyridinium chloride mediated mesoporous MnHAp nanorods synthesis. Pure and Mn doped HAp samples were examined using Raman spectroscopy, X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) studies to confirm the prepared HAp nanorods. Furthermore, the fabrication of manganese-doped HAp was successful with the formation of a hexagonal crystal lattice without disturbing the HAp phase. It is because, at the time of synthesis, PO43- ions form an electrostatic interaction with the Mn ions. Furthermore, Mn-doped HAp samples showed a reduction in their sizes of 15, 10-15, 5-10 nm width, and 80-100, 10-15, 20-30 nm length with varied pore diameters and surface area. The pure HAp, MnHAp-1, MnHAp-2, and MnHAp-3 nanorods disclose the surface area of 39.4, 18.0, 49.2, and 80.4 m2 g-1, with a pore volume of 0.0102, 0.0047, 0.0143, and 0.0447 cm3 g-1, the corresponding pore diameter was estimated to be 6, 7, 6, and 4 nm, respectively. Moreover, antibacterial activity reveals effective bactericidal action against infections causing pathogens whereas cytotoxicity examination (MTT assay), and zebrafish results reveal their non-toxic behavior. Therefore, it is evident from the study, that rapid fabrication of mesoporous and diverse structured MnHAp nanorods could be convenient with pyridinium chloride enabled microwave-assisted method as a bactericidal biomaterial for implant applications.

Impact of Iron on the Fe-Co-Ni Ternary Nanocomposites Structural and Magnetic Features Obtained via Chemical Precipitation Followed by Reduction Process for Various Magnetically Coupled Devices Applications.

This paper presents the synthesis of Fe-Co-Ni nanocomposites by chemical precipitation, followed by a reduction process. It was found that the influence of the chemical composition and reduction temperature greatly alters the phase formation, its structures, particle size distribution, and magnetic properties of Fe-Co-Ni nanocomposites. The initial hydroxides of Fe-Co-Ni combinations were prepared by the co-precipitation method from nitrate precursors and precipitated using alkali. The reduction process was carried out by hydrogen in the temperature range of 300-500 °C under isothermal conditions. The nanocomposites had metallic and intermetallic phases with different lattice parameter values due to the increase in Fe content. In this paper, we showed that the values of the magnetic parameters of nanocomposites can be controlled in the ranges of MS = 7.6-192.5 Am2/kg, Mr = 0.4-39.7 Am2/kg, Mr/Ms = 0.02-0.32, and HcM = 4.72-60.68 kA/m by regulating the composition and reduction temperature of the Fe-Co-Ni composites. Due to the reduction process, drastic variations in the magnetic features result from the intermetallic and metallic face formation. The variation in magnetic characteristics is guided by the reduction degree, particle size growth, and crystallinity enhancement. Moreover, the reduction of the surface spins fraction of the nanocomposites under their growth induced an increase in the saturation magnetization. This is the first report where the influence of Fe content on the Fe-Co-Ni ternary system phase content and magnetic properties was evaluated. The Fe-Co-Ni ternary nanocomposites obtained by co-precipitation, followed by the hydrogen reduction led to the formation of better magnetic materials for various magnetically coupled device applications.

Green synthesis of stable antioxidant, anticancer and photocatalytic activity of zinc oxide nanorods from Leea asiatica leaf.

The present work reveals zinc oxide nanorods (ZnO NRs) obtained via green synthesis approach utilizing phytochemicals present in the Leea asiatica plant. The synthesized ZnO NRs was confirmed by various characterization methods like X-ray diffraction, FTIR, SEM-EDX, UV-vis, TEM and Raman spectra analysis. The obtained nanorods show less particle size with a distinctive high surface area. The photodegradation activity of obtained ZnO NRs shows 81.3 % of dye degradation at high concentration whereas 42.9 % in low concentration and also antioxidant test shows a better result for free radical scavenging. To understand the safety of the ZnO NRs zebrafish embryos was utilized as a model and found to be less toxic after assessment. Furthermore, to understand the anticancer activity of ZnO NRs it was assessed against breast cancer cell line through MTT, XTT, NRU, and LDH assay. The ZnO NRs exposed against breast cancer cell line (MCF-7) had resulted in necrosis and apoptosis which was further confirmed by genotoxicity assay. Also, the molecular mechanisms behind the necrosis and apoptosis are also discussed to show the involvement of ZnO NRs towards breast cancer cells (MCF-7). The present study on ZnO NRs gives a wide spectrum understanding of using ZnO NRs as a potential drug for human breast cancer by showing its physiological pathways as well as a novel way to synthesize ZnO NRs using Leea asiatica plant extract.

Data on the current-voltage dependents of nickel hollow microspheres based thermo-electrochemical in alkaline electrolyte.

Low-grade waste heat harvesting and conversion into electric energy is an important way of renewable energy development and thermo-electrochemical cells are promising devices to solve this problem. In this paper, we report original data on the current density and maximum output power dependents on voltage of the thermos-cells with nickel hollow microspheres electrodes and different electrolyte concentration (from 0.1 to 3.0 mol/l)which exhibit excellent hypothetical Seebeck coefficient and accordingly high open-circuit voltage values at low source temperature. The composition, microstructure and morphology of the hollow nickel microspheres based electrodes are included here. Because of the low cost of nickel based thermo-cells could be commercially feasible for harvesting low-quality thermal energy, in this connection, the raw data of measurements of their properties are given here. The data is related to "High Seebeck coefficient thermo-electrochemical cell using nickel hollow microspheres electrodes", Burmistrov et al., Renewable Energy, 2020 [1].

Ascorbic Acid-Assisted Microwave Synthesis of Mesoporous Ag-Doped Hydroxyapatite Nanorods from Biowaste Seashells for Implant Applications.

Post-surgery implant infection is one of the most challenging issues in orthopedics and it is mainly caused by infective micro-organisms. A potential approach to overcome this issue is developing biomaterials with efficient antibacterial activity. The main intention of this present research is devoted to ascorbic acid-assisted microwave synthesis of mesoporous (silver) Ag-doped hydroxyapatite (HAp) nanorods using biowaste seashells with antibacterial properties. XRD, FTIR, and Raman spectroscopy results revealed that the synthesized nanoparticles are hexagonal crystalline HAp. Further, the silver-doped HAp was also successfully produced without affecting the HAp crystalline phase by forming electrostatic interaction with PO43- ions during the synthesis. The morphological features confirm that the pure HAp is elongated mesoporous nanorods with 20 nm width and 300-500 nm length. However, silver doped HAp nanoparticles such as AgHA-1, AgHA-2, and AgHA-3 are found to be similar mesoporous rods but with different aspect ratios in sizes of 15, 10-15, and 5-10 nm width and 80-100, 10-15, and 20-30 nm length. The BET specific surface areas were obtained as 29 ± 3, 84 ± 2, 87 ± 2, and 128 ± 3 m2 g-1, and pore diameters were 4.68, 4.18, 9.30, and 3.77 nm, respectively, for pure HA, AgHA-1, AgHA-2, and AgHA-3. Therefore, HAp nanoparticles with different dimensions and mesoporous structures could be rapidly prepared using a microwave-assisted method and ascorbic acid as a supporting material. In addition, the synthesized HAp nanoparticles are analyzed for its antibacterial and cytotoxicity studies. The antibacterial and cytotoxicity study clearly reveals that the Ag-doped HAp nanorods are efficiently antibacterial and nontoxic in nature. Hence, it is clear that the ascorbic acid-enabled microwave-assisted method will be one of the best methods for the rapid production of HAp nanoparticles with different dimensions and mesoporous structures for its application as an implant material.

Sono-synthesis approach of reduced graphene oxide for ammonia vapour detection at room temperature.

In this paper, we report the sono-synthesis of reduced graphene oxide (rGO) using polyethyleneimine (PEI), and its performance for ammonia vapour detection at room temperature. Graphene oxide (GO) and reduced graphene oxide (rGO) were prepared by sonication method by using low-frequency ultrasound under ambient condition and films were deposited by Doctor Blade method. The rGO, which has vapour accessible structure showed a good sensing response with a minimum detection limit of 1 ppm and the detection range from 1 ppm to 100 ppm. The sensing response was found to be 2% at 1 ppm and 34% at 100 ppm of ammonia and the developed sensor operated at room temperature. The sensor displays a response time of 6 s and a recovery time of 45 s towards 100 ppm of ammonia vapour. The source for the highly sensitive, selective and stable detection of ammonia with negligible interference from other vapours is discussed and reported. We believe reduced graphene oxide (rGO) could potentially be used to manufacture a new generation of low-power portable ammonia sensors.

Investigation of discharged aerosol nanoparticles during chemical precipitation and spray pyrolysis for developing safety measures in the nano research laboratory.

Nowadays, the demands for the nanoparticles are increasing due to their tremendous applications in various fields. As a consequence, the discharge of nanoparticles into the atmosphere and environment is also increasing, posing a health threat and environmental damage in terms of pollution. Thus, an extensive research is essential to evaluate the discharge of these nanoparticles into the environment. Keeping this in mind, the present investigation aimed to analyze the discharge of aerosol nanoparticles that are synthesized in the laboratory via chemical precipitation and spray pyrolysis methods. The results indicated that the chemical precipitation method discharges a higher concentration of nanoparticles in the work site when compared to the spray pyrolysis method. The aerosol concentration also varied with the different steps involved during the synthesis of nanoparticles. The average particle's concentration in air for chemical precipitation and spray pyrolysis methods was around 1,037,476 and 883,421particles/cm3. In addition, the average total discharge of nanoparticles in the entire laboratory was also examined. A significant variation in the concentration of nanoparticles was noticed, during the processing of materials and the concentration of particles (14-723nm) exceeding the daily allowed concentration to about 70-170 times was observed over a period of 6 months. Thus, the results of the present study will be very useful in developing safety measures and would help in organizing the rules for people working in nanotechnology laboratories to minimize the hazardous effects.

Nitrobacter sp. extract mediated biosynthesis of Ag2O NPs with excellent antioxidant and antibacterial potential for biomedical application.

In this study, extracellular extract of plant growth promoting bacterium, Nitrobacter sp. is used for the bioconversion of AgNO3 (silver nitrate) into Ag2O (silver oxide nanoparticles). It is an easy, ecofriendly and single step method for Ag2O NPs synthesis. The bio-synthesized nanoparticles were characterized using different techniques. UV-Vis results showed the maximum absorbance around 450 nm. XRD result shows the particles to have faced centered cubic (fcc) crystalline nature. FTIR analysis reveals the functional groups that are involved in bioconversion such as C-N, N-H and C=O. Energy-dispersive X-ray spectroscopy (EDAX) spectrum confirms that the prepared nanoparticle is Ag2O NPs. Particle size distribution result reveals that the average particle size is around 40 nm. The synthesized Ag2O NPs found to be almost spherical in shape. Biosynthesized Ag2O NPs possess good antibacterial activity against selected Gram positive and Gram negative bacterial strains namely Salmonella typhimurium, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae when compared to standard antibiotic. In addition, Ag2O NPs exhibits excellent free radical scavenging activity with respect to dosage. Thus, this study is a new approach to use soil bacterial extract for the production of Ag2O NPs for biomedical application.

Influence of ZrO2, SiO2, Al2O3 and TiO2 nanoparticles on maize seed germination under different growth conditions.

The focus of this investigation is to evaluate the phytotoxicity of selected metal oxide nanoparticles and microparticles as a function of maize seed germination and root elongation under different growth conditions (Petri plate, cotton and soil). The results of seed germination and root elongation experiments reveal that all the growth conditions show almost similar results. Alumina (Al2O3) and titania (TiO2) nanoparticles significantly reduce the germination percentage, whereas silica (SiO2) nanoparticles and microparticles enhance the same. The results of nanoparticles and microparticles of zirconia (ZrO2) are found to be same as those of controls. Root elongation is enhanced by SiO2 nanoparticles and microparticles treatment, whereas inhibition is observed with Al2O3 and TiO2 nanoparticles and microparticles. The X-ray fluorescence spectrometry data of the treated and control seed samples show that seeds uptake SiO2 particles to a greater extent followed by TiO2, Al2O3 and ZrO2. In addition, the uptake of nanoparticles is found to be greater than that of microparticles. Thus, the tested metal oxides penetrated seeds at the nanoscale as compared with the microscale. This study clarifies phytotoxicity of nanoparticles treated in different growth substrates and highlights the impact of nanoparticles on environment and agricultural systems.

Facile and novel synthetic method to prepare nano molybdenum and its catalytic activity.

This study reports on a facile and economical synthetic method to prepare nano molybdenum by solid-state reaction technique. Metallic nano molybdenum was synthesised from molybdenum trioxide, molybdenum IV oxide and molybdenum VI oxide through thermal decomposition technique. Metallic nano molybdenum prepared from molybdenum IV oxide was used to study the catalytic effect of molybdenum nanoparticles on the growth of Anabaena sp. The increase in concentration of nano molybdenum from 0.1 to 100% in BG11 (N⁻ Mo⁻ + nano Mo) medium increases heterocyst frequency. The chlorophyll and protein content in Anabaena sp. was found to improve when compared with bulk molybdenum particles and showed a positive influence to be used as a nano nutrient for Anabaena sp.

Effect of contact angle, zeta potential and particles size on the in vitro studies of Al2O3 and SiO2 nanoparticles.

Currently, nanometal oxides find their role in different biological applications such as tissue engineering, implant and bone replacement materials. Owing to the increased use of nanoparticles, it is necessary to understand their release and toxicity in the biological system. In this regard, three independent studies such as in vitro cytotoxicity, antioxidant activity and biocompatibility of nano- and micrometal oxide particles such as alumina (Al2O3) and silica (SiO2) are evaluated. It is evident from cell viability study that nanoAl2O3 and SiO2 particles are less toxic when compared with microAl2O3 and SiO2 to NIH 3T3 cell lines up to 200 µg/ml. Antioxidant properties of micro- and nanoAl2O3 in terms of radical scavenging percentage for micro- and nanoAl2O3 are 59.1% and 72.1%, respectively, at 100 mg. Similarly, the radical scavenging percentage of nano- and bulk SiO2 are 81.0% and 67.2%, respectively. The present study reveals that the cellular behaviour, interaction and biocompatibility of metal oxides differ with dose, particle size, contact angle and zeta potential. The present study opens up a new strategy to analyse in vitro nanotoxicity.

Application of silica nanoparticles in maize to enhance fungal resistance.

In this study, maize treated with nanosilica (20-40 nm) is screened for resistance against phytopathogens such as Fusarium oxysporum and Aspergillus niger and compared with that of bulk silica. The resistivity is measured for disease index and expression of plant responsive compounds such as total phenols, phenylalanine ammonia lyase, peroxidase and polyphenol oxidase. The results indicate that nanosilica-treated plant shows a higher expression of phenolic compounds (2056 and 743 mg/ml) and a lower expression of stress-responsive enzymes against both the fungi. Maize expresses more resistance to Aspergillus spp., than Fusarium spp. These results show significantly higher resistance in maize treated with nanosilica than with bulk, especially at 10 and 15 kg/ha. In addition, hydrophobic potential and silica accumulation percentage of nanosilica treated maize (86.18° and 19.14%) are higher than bulk silica treatment. Hence, silica nanoparticles can be used as an alternative potent antifungal agent against phytopathogens.

Effect of nanosilica and silicon sources on plant growth promoting rhizobacteria, soil nutrients and maize seed germination.

The study was aimed at evaluating the effect of nanosilica and different sources of silicon on soil properties, total bacterial population and maize seed germination. Nanosilica was synthesised using rice husk and characterised. Silica powder was amorphous (50 nm) with >99.9% purity. Sodium silicate treated soil inhibited plant growth promoting rhizobacteria in contrast to nanosilica and other bulk sources. Surface property and effect of soil nutrient content of nanosilica treatment were improved. Colony forming unit (CFU) was doubled in the presence of nanosilica from 4 × 105 CFU (control) to 8 × 105 CFU per gram of soil. The silica and protein content of bacterial biomass clearly showed an increase in uptake of silica with an increase in nanosilica concentration. Nanosilica promoted seed germination percentage (100%) in maize than conventional Si sources. These studies show that nanosilica has favourable effect on beneficial bacterial population and nutrient value of soil.

Impact of nano and bulk ZrO2, TiO2 particles on soil nutrient contents and PGPR.

Currently, nanometal oxides are used extensively in different industries such as medicine, cosmetics and food. The increased consumption of nanoparticles (NPs) leads the necessity to understand the fate of the nanoparticles in the environment. The present study focused on the ecotoxicological behaviour of bulk and nano ZrO2 (Zirconia) and TiO2 (Titania) particles on PGPR (plant growth promoting rhizobacteria), soil and its nutrient contents. The microbial susceptibility study showed that nano TiO2 had 13 +/- 0.9 mm (B. megaterium), 15 +/- 0.2 mm (P. fluorescens), 16 +/- 0.2 mm (A. vinelandii) and 12 +/- 0.3 mm (B. brevis) zones of inhibition. However, nano and bulk ZrO2 particles were non-toxic to PGPR. In addition, it was found that toxicity varied depends on the medium of reaction. The soil study showed that nano TiO2 was found to be highly toxic, whereas bulk TiO2 was less toxic towards soil bacterial populations at 1000 mg L(-1). In contrast, nano and bulk ZrO2 were found to be inert at 1000 mg L(-1). The observed zeta potential and hydrophobicity of TiO2 particles causes more toxic than ZrO2 in parallel with particle size. However, nano TiO2 decreases the microbial population as well as nutrient level of the soil but not zirconia. Our finding shows that the mechanism of toxicity depends on size, hydrophobic potential and zeta potential of the metal oxide particles. Thus, it is necessary to take safety measures during the disposal and use of such toxic nanoparticles in the soil to prevent their hazardous effects.