Vani Mishra

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.

Detoxification and Tolerance of Heavy Metals in Plants

Abstract Plant growth and metabolisms are regulated by some heavy metals found in Earths crust because they are active constituents of various enzymes. However, their increased concentration may lead to different toxic effects, inhibiting plant growth and development. There are some plants that are capable of surviving in the presence of heavy metals, apparently by adapting the mechanism that involved in common homeostasis as well as removal of metal ions. Plants have diverse mechanisms for metal detoxification, enabling them to tolerate heavy metal stress. The defense systems against heavy metal stress include mycorrhizae, cellular exudates, plasma membrane, heat shock proteins, phytochelatins (PCs), metallothioneins (MTs), organic acids, and amino acids. All the mechanism involved the tolerance of heavy metal concentration at cellular level to avoid the negative impacts. Extracellular plants include roles for mycorrhizae and extracellular exudates in the plasma membrane either by dropping by absorption of heavy metal or by inducing the efflux pumping of metal ions. On the other hand, intracellularly heat shock proteins, MTs, organic acids, amino acids, and PCs also play a vital role in tolerance of different heavy metals. Few metal transporters have been identified in the past few years that actively participate in tolerance of metal specificity. Enhanced application of molecular genetics has shown their eminent contribution in understanding the mechanism of heavy metal tolerance in plants.

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 pathogens 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.

Interactions of Nanoparticles with Plants

The successful application of nano-structures in biomedicine and agriculture has emerged as an important and new area of research. Crop production and its improvement are essential to maintain a self-sustainable world and to feed its ever-increasing population. This can be widely achieved through “agri-nanotechnology,” which promises natural resource management through novel tools and technological platforms within limited resources of land and water. Nanotechnology has the potential to advance agricultural productivity through designing and fabricating materials, devices and systems at the nano-scale that could exploit the properties (physical, chemical, biological) at the desired dimension. Nanoparticles (NPs) differentiated on the basis of their occurrence, kind, and composition can be employed in various ways to manage growth promotion in plants. These recent developments have opened broader avenues in the advancement of genetically modified crops through site directed delivery of various macromolecules including genes and drugs, smart delivery systems of agrochemicals, early detection of diseases and pathogens, plant protecting chemicals and precision farming techniques. However, this could be successfully facilitated in plants only after enhancing our knowledge about the uptake, transportation, and accumulation of NPs in plants. Since reports reveal contradictory effects of NPs on plants, optimization of experimental conditions like medium of plant growth, size, and shape of NPs, etc. should be performed. This would increase the potential of nano-formulations, nano-genetic manipulations and nano-array-based technologies for plant management. Controlling plant pathogens, their prevention and disease treatments using various nanocides are among other major milestones of nanotechnology. Comprehending the interaction between plants and their environment (soil, water, and atmosphere), it becomes important to study the impact of nanotechnology on agriculture with references to toxicity concerns. Moreover, the growth and metabolic functions in response to a myriad of nanoparticles vary differently among plants. They provide pathways to NPs and result in their bioaccumulation into food chains to reach higher species of ecosystems. The Indian economy largely depends onagriculture, therefore research and development in agricultural nanotechnology is of paramount importance.

Immunotoxicological impact and biodistribution assessment of bismuth selenide (Bi 2 Se 3 ) 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.

Land Reformation Using Plant Growth–Promoting Rhizobacteria in the Context of Heavy Metal Contamination

Abstract Our environment is surrounded with toxic substances that affect everything in several forms, especially green plants, which are the lungs of nature but grown in soil. These noxious things pollute one of the most important medium of life in earth known as the rhizosphere, which is the largest habitat of rhizobacteria on Earth. It is found in and around the roots of crop plants, enhance the crop yield by several mechanisms, and remediate the rhizosphere by eliminating the metal contaminants from soil. These metal toxicants are absorbed mainly by accumulation and biotransformation. Metal contaminations in soil is a major result of human activities such as mining and can be differentiated into three categories on the basis of their properties: reactive oxygen species, overcrowding of functional groups of biomolecules, and displacement of functional groups leading to ecotoxicological risks. The ecotoxic effects of heavy metal contamination have the ability to destroy the receptive parts of the plants and rhizospheric microbes, because once they enter in the soil, they adversely affect the food web due to the biomagnifications. The foremost soil pollutants are Al, arsenic, cadmium, chromium, mercury, lead, antimony, and selenium. The removal of soil contaminants using plant growth–promoting rhizobacteria (PGPR) is believed to be more efficient in comparison to the traditional methods because their activity persists and they have a diversity of soil microorganisms to sustain healthy environment. PGPR are known to affect heavy metals in ways such as phosphate solubilization, chelation, acidification, and redox changes ultimately changing the metal speciation, Production of phytohormones, N2 fixation, siderophores, and conversion of nutrients when they are either applied to seeds or incorporated into the soil to complete the phytoremediation process. Thus, the use of rhizobacteria in combination with plants could be a fast-developing field of research for land reform.