Author Correction: Immunotoxicological impact and biodistribution assessment of bismuth selenide (Bi2Se3) nanoparticles following intratracheal instillation in mice.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Immunotoxicological impact and biodistribution assessment of bismuth selenide (Bi2Se3) nanoparticles following intratracheal instillation in mice.

Variously synthesized and fabricated Bi2Se3 nanoparticles (NPs) have recently been explored for their theranostic properties. Herein, we investigated the long term in-vivo biodistribution of Bi2Se3 NPs and systematically screened its immune-toxic potential over lungs and other secondary organs post intratracheal instillation. X-Ray CT scan and ICP MS results revealed significant particle localization and retention in lungs monitored for 1 h and 6 months time period respectively. Subsequent particle trafficking was observed in liver, the major reticuloendothelial organ followed by gradual but incomplete renal clearance. Pulmonary cytotoxicity was also found to be associated with persistent neutrophilic and ROS generation at all time points following NP exposure. The inflammatory markers along with ROS generation further promoted oxidative stress and exaggerated additional inflammatory pathways leading to cell death. The present study, therefore, raises serious concern about the hazardous effects of Bi2Se3 NPs and calls for further toxicity assessments through different administration routes and doses as well.

Tolerance and Reduction of Chromium(VI) by Bacillus sp. MNU16 Isolated from Contaminated Coal Mining Soil.

The bacterium MNU16 was isolated from contaminated soils of coal mine and subsequently screened for different plant growth promoting (PGP) activities. The isolate was further identified by 16S rRNA sequencing as Bacillus subtilis MNU16 with IAA concentration (56.95 ± 0.43 6µg/ml), siderophore unit (9.73 ± 2.05%), phosphate solubilization (285.13 ± 1.05 µg/ml) and ACC deaminase activity (116.79 ± 0.019 µmoles α-ketobutyrate/mg/24 h). Further, to evaluate the metal resistance profile of bacterium, the isolate was screened for multi-metal resistance (viz. 900 mg/L for Cr, 600 mg/L for As, 700 mg/L for Ni and 300 mg/L for Hg). Additionally, the resistance pattern of B. subtilis MNU16 against Cr(VI) (from 50 to 300 mg/L) treatments were evaluated. An enriched population was observed at 0-200 mg/L Cr(VI) concentration while slight reductions were observed at 250 and 300 mg/L Cr(VI). Further, the chromium reduction ability at 50 mg/L of Cr(VI) highlighted that the bacterium B. subtilis MNU16 reduced 75% of Cr(VI) to 13.23 mg/L within 72 h. The localization of electron dense precipitates was observed in the TEM images of B. subtilis MNU16 which is might be due to the reduction of Cr(VI) to Cr(III). The data of fluorescence microscopy and flow cytometry with respect to Cr(VI) treatments (50-300 mg/L) showed a similar pattern and clearly revealed the less toxic effect of hexavalent chromium upto 200 mg/L Cr(VI) concentration. However, toxicity effects were more pronounced at 300 mg/L Cr(VI). Therefore, the present study suggests that the plant growth promoting potential and resistance efficacy of B. subtilis MNU16 will go a long way in developing an effective bioremediation approach for Cr(VI) contaminated soils.

Abscisic Acid Signaling and Abiotic Stress Tolerance in Plants: A Review on Current Knowledge and Future Prospects.

Abiotic stress is one of the severe stresses of environment that lowers the growth and yield of any crop even on irrigated land throughout the world. A major phytohormone abscisic acid (ABA) plays an essential part in acting toward varied range of stresses like heavy metal stress, drought, thermal or heat stress, high level of salinity, low temperature, and radiation stress. Its role is also elaborated in various developmental processes including seed germination, seed dormancy, and closure of stomata. ABA acts by modifying the expression level of gene and subsequent analysis of cis- and trans-acting regulatory elements of responsive promoters. It also interacts with the signaling molecules of processes involved in stress response and development of seeds. On the whole, the stress to a plant can be susceptible or tolerant by taking into account the coordinated activities of various stress-responsive genes. Numbers of transcription factor are involved in regulating the expression of ABA responsive genes by acting together with their respective cis-acting elements. Hence, for improvement in stress-tolerance capacity of plants, it is necessary to understand the mechanism behind it. On this ground, this article enlightens the importance and role of ABA signaling with regard to various stresses as well as regulation of ABA biosynthetic pathway along with the transcription factors for stress tolerance.

Power and Time Dependent Microwave Assisted Fabrication of Silver Nanoparticles Decorated Cotton (SNDC) Fibers for Bacterial Decontamination.

Plasmonic nanoparticles (NPs) such as silver and gold have fascinating optical properties due to their enhanced optical sensitivity at a wavelength corresponding to their surface plasmon resonance (SPR) absorption. Present work deals with the fabrication of silver nanoparticles decorated cotton (SNDC) fibers as a cheap and efficient point of contact disinfectant. SNDC fibers were fabricated by a simple microwave assisted route. The microwave power and irradiation time were controlled to optimize size and density of silver nanoparticles (SNPs) on textile fibers. As prepared cotton fabric was characterized for ATR-FTIR, UV-VIS diffuse reflectance, SEM and TEM investigations. Size of SNPs as well as total density of silver atoms on fabric gets increased with the increase of microwave power from 100 W to 600 W. The antibacterial efficacy of SNPs extracted from SNDC fibers was found to be more effective against Gram-negative bacteria than Gram-positive bacteria with MIC 38.5 ± 0.93 µg/mL against Salmonella typhimurium MTCC-98 and 125 ± 2.12 µg/mL against Staphylococcus aureus MTCC-737, a linear correlation coefficient with R2 ranging from ∼0.928-0.935 was also observed. About >50% death cells were observed through Propidium Iodide (PI) internalization after treatment of SNPs extracted from SNDC fibers with concentration 31.25 µg/mL. Generation of ROS and free radical has also been observed which leads to cell death. Excellent Escherichia coli deactivation efficacy suggested that SNDC fibers could be used as potentially safe disinfectants for cleaning of medical equipment, hand, wound, water and preservation of food and beverages.

Nitric Oxide Ameliorates Zinc Oxide Nanoparticles Phytotoxicity in Wheat Seedlings: Implication of the Ascorbate-Glutathione Cycle.

The present study investigates ameliorative effects of nitric oxide (NO) against zinc oxide nanoparticles (ZnONPs) phytotoxicity in wheat seedlings. ZnONPs exposure hampered growth of wheat seedlings, which coincided with reduced photosynthetic efficiency (Fv/Fm and qP), due to increased accumulation of zinc (Zn) in xylem and phloem saps. However, SNP supplementation partially mitigated the ZnONPs-mediated toxicity through the modulation of photosynthetic activity and Zn accumulation in xylem and phloem saps. Further, the results reveal that ZnONPs treatments enhanced levels of hydrogen peroxide and lipid peroxidation (as malondialdehyde; MDA) due to severely inhibited activities of the following ascorbate-glutatione cycle (AsA-GSH) enzymes: ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase and dehydroascorbate reductase, and its associated metabolites ascorbate and glutathione. In contrast to this, the addition of SNP together with ZnONPs maintained the cellular functioning of the AsA-GSH cycle properly, hence lesser damage was noticed in comparison to ZnONPs treatments alone. The protective effect of SNP against ZnONPs toxicity on fresh weight (growth) can be reversed by 2-(4carboxy-2-phenyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxide, a NO scavenger, and thus suggesting that NO released from SNP ameliorates ZnONPs toxicity. Overall, the results of the present study have shown the role of NO in the reducing of ZnONPs toxicity through the regulation of accumulation of Zn as well as the functioning of the AsA-GSH cycle.

Uptake, Accumulation and Toxicity of Silver Nanoparticle in Autotrophic Plants, and Heterotrophic Microbes: A Concentric Review.

Nanotechnology is a cutting-edge field of science with the potential to revolutionize today's technological advances including industrial applications. It is being utilized for the welfare of mankind; but at the same time, the unprecedented use and uncontrolled release of nanomaterials into the environment poses enormous threat to living organisms. Silver nanoparticles (AgNPs) are used in several industries and its continuous release may hamper many physiological and biochemical processes in the living organisms including autotrophs and heterotrophs. The present review gives a concentric know-how of the effects of AgNPs on the lower and higher autotrophic plants as well as on heterotrophic microbes so as to have better understanding of the differences in effects among these two groups. It also focuses on the mechanism of uptake, translocation, accumulation in the plants and microbes, and resulting toxicity as well as tolerance mechanisms by which these microorganisms are able to survive and reduce the effects of AgNPs. This review differentiates the impact of silver nanoparticles at various levels between autotrophs and heterotrophs and signifies the prevailing tolerance mechanisms. With this background, a comprehensive idea can be made with respect to the influence of AgNPs on lower and higher autotrophic plants together with heterotrophic microbes and new insights can be generated for the researchers to understand the toxicity and tolerance mechanisms of AgNPs in plants and microbes.

Reactive Oxygen Species (ROS): Beneficial Companions of Plants' Developmental Processes.

Reactive oxygen species (ROS) are generated inevitably in the redox reactions of plants, including respiration and photosynthesis. In earlier studies, ROS were considered as toxic by-products of aerobic pathways of the metabolism. But in recent years, concept about ROS has changed because they also participate in developmental processes of plants by acting as signaling molecules. In plants, ROS regulate many developmental processes such as cell proliferation and differentiation, programmed cell death, seed germination, gravitropism, root hair growth and pollen tube development, senescence, etc. Despite much progress, a comprehensive update of advances in the understanding of the mechanisms evoked by ROS that mediate in cell proliferation and development are fragmentry and the matter of ROS perception and the signaling cascade remains open. Therefore, keeping in view the above facts, an attempt has been made in this article to summarize the recent findings regarding updates made in the regulatory action of ROS at various plant developmental stages, which are still not well-known.

Titanium dioxide nanoparticles augment allergic airway inflammation and Socs3 expression via NF-κB pathway in murine model of asthma.

Titanium dioxide nanoparticles (nTiO2) previously considered to possess relatively low toxicity both in vitro and in vivo, although classified as possibly carcinogenic to humans. Also, their adjuvant potential has been reported to promote allergic sensitization and modulate immune responses. Previously, in OVA induced mouse model of asthma we found high expression of Socs3 and low expression of Stat3 and IL-6. However, a clear understanding regarding the signaling pathways associated with nTiO2 adjuvant effect in mouse model of asthma is lacking. In the present study we investigated the status of Stat3/IL-6 and Socs3 and their relationship with NF-κB, with nTiO2 as an adjuvant in mouse model of asthma. nTiO2 when administered with ovalbumin (OVA) during sensitization phase augmented airway hyper-responsiveness (AHR), biochemical markers of lung damage and a mixed Th2/Th1 dependent immune response. At the same time, we observed significant elevation in the levels of Stat3, Socs3, NF-κB, IL-6 and TNF-α. Furthermore, transient in vivo blocking of NF-κB by NF-κB p65 siRNA, downregulated the expression of Socs3, IL-6 and TNF-α. Our study, thus, shows that nTiO2 exacerbate the inflammatory responses in lungs of pre-sensitized allergic individuals and that these changes are regulated via NF-κB pathway.

Exploration of anti-Malassezia potential of Nyctanthes arbor-tristis L. and their application to combat the infection caused by Mala s1 a novel allergen.

BACKGROUND: Malassezia commensal yeasts along with multitude of antigens have been found to be associated with various skin disorders including Pityriasis versicolor (PV). Amongst them Mala s1, a 37 kDa protein has been proved to be a major allergen reacting with a large panel of sera. However, there exists no therapeutic alternative to combat such problems in form of plant based natural compounds. The purpose of this study is in the first place, to determine the anti-Malassezia activity of Nyctanthes arbor-tristis L. (NAT) ethanolic leaf extract through turbidimetric growth curves, disruption of plasma membrane and secondly, it aims to present in silico validation of its active constituents over Mala s1a novel allergen. METHODS: The antifungal susceptibility 50 % ethanolic extract of NAT was determined by broth microdilution method according to CLSI guidelines. Further MICs and IC50 were determined spectrophotometrically using the software SoftMax® Pro-5 (Molecular Devices, USA). Active constituents mediated disruption of plasma membrane was studied through flowcytometry by permeabilization of fluorescent dye Propidium Iodide (PI). Antioxidant activity of the extract was determined using the DPPH stable radical. Molecular validation of fungal DNA from the extract was observed using PCR amplification. In silico analysis of its active constituents over Mala s1 was performed using HEX software and visualized through Pymol. RESULTS: The anti-Malassezia potential of NAT leaf extracts reflected moderate MIC 1.05 µg/µl against M. globosa, while least effective against M. restricta with MIC 1.47 µg/µl. A linear correlation coefficient R (2) = 0.866 was obtained in case of M. globosa while minimum was observed in M. restricta with R (2) = 0.732. The flow cytometric data reveal ~ 75 % cell death when treated with active constituents ß-Sitosterol and Calceolarioside A. The docking confirmations and the interaction energies between Mala s1 and the active constituents (ß-Sitosterol and Calceolarioside A) from extracts showed an effective binding which suggests Mala s1 as efficient allergen for site specific targeting. CONCLUSIONS: This study revealed that Nyctanthes arbor-tristis L. (NAT) extracts possess high anti-Malassezia potential which is driven mainly by disruption of plasma membrane. Also in silico validation and molecular modeling studies establishes Mala s1 as a novel allergen that could be a potential target in disease treatment. Our results would also provide a foundation for the development of new therapeutic approach using NAT extract as lead compound with high antioxidant property as an added trait for skin care.

Pharmaco-Phylogenetic Investigation of Methyl Gallate Isolated from Acacia nilotica (L.) Delile and Its Cytotoxic Effect on NIH3T3 Mouse Fibroblast.

Present exploration deals with the therapeutic perspective of methyl gallate isolated from the leaf extract of Acacia nilotica (L.) Delile in contrast to food-borne bacterial pathogen's viz., Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, Pseudomonas aeruginosa and Staphylococcus aureus with their evolutionary succession. The extract was subjected to phytochemical analysis and isolated compound was identified as methyl gallate using UV-vis, IR and NMR spectra. It was found most potent against K. pneumoniae with its minimum inhibition concentration (MIC) of 0.32 mg/ml and minimum bactericidal concentration (MBC) at 0.62 mg/ml. The correlation of MIC values with an evolutionary succession assists the relationship between their genetic and toxic properties. The cytotoxic pursuit of methyl gallate was additionally assessed over NIH3T3 mouse fibroblast by Neutral red (NR) uptake, MTT cell proliferation assay and did not disclose any relevant influence on cell viability as well as cell proliferation. As such, the methyl gallate extracted from the leaf of A. nilotica holds massive antibacterial aptitude and hands out towards a new paradigm for food and pharmaceutical industries.

Management of cosmetic embarrassment caused by Malassezia spp. with fruticose lichen Cladia using phylogenetic approach.

During anti-Malassezia screening of plants by CLSI broth microdilution method, Cladia aggregata (Swartz) Nyl. (family Cladoniaceae), a fruticose lichen from Sikkim (northeast Himalayan region), has been found effective at minimum inhibitory concentrations (mg/mL) of 2.72, 0.63, and 1.28 against yeast-like fungi namely, M. furfur, M. globosa and M. sympodialis, respectively. These test pathogens are responsible for pityriasis versicolor (PV) and seborrheic dermatitis (SD) in humans. We tried to establish the reason for variable MICs against various Malassezia spp. using bioinformatical tools, thereby reducing the cost of the experimentation. This is the first report on anti-Malassezia activity of C. aggregata and thus can serve as a potential source for the development of cosmaceuticals.

Comparison of two ferns (Adiantum capillus-veneris Linn. and Microsorium punctatum (Linn.) Copel) for their Cr accumulation potential and antioxidant responses.

Study was undertaken to compare Cr accumulation in two ferns (Adiantum capillus-veneris Linn. and Microsorium punctatum (Linn.) Copel) and the role of antioxidants were also investigated towards metal tolerance in order to assess the use of ferns in phytomediation/ phytostabilization. Different concentrations (0, 50, 100, 150 microg g(-1) dw) of Cr were added to fern planted in pot containing 1 kg soil. In both the ferns, Cr accumulation increased with increase in metal concentration and maximum accumulation of 800.5 microg g(-1) (fronds) and 1457.4 microg g(-1) (roots) in M. punctatum and 660.8 microg g(-1) (fronds) and 1259.6 microg g(-1) (roots) in A. capillus-veneris was recorded. The increase in the levels of malondialdehyde, antioxidants and antioxidant enzymes (superoxide dismutase, glutathione peroxidase) in A. capillus-veneris was less pronounced than M. punctatum under Cr exposure as compared to their respective controls. In view of less decrease in chlorophyll content and antioxidants along with higher accumulation of Cr in the fronds M. punctatum, is indicative of its higher tolerance towards Cr. However, bioaccumulation factor (concentration of Cr in fronds/concentration of Cr in the soil) of both the ferns was recorded > 1 which qualifies the plants as potential Cr hyperaccumulator and suitable for phytoremediaton.