Shashi Kant Shukla

Prediction and validation of gold nanoparticles (GNPs) on plant growth promoting rhizobacteria (PGPR): a step toward development of nano-biofertilizers

Abstract Several soil microbes are present in the rhizosphere zone, especially plant growth promoting rhizobacteria (PGPR), which are best known for their plant growth promoting activities. The present study reflects the effect of gold nanoparticles (GNPs) at various concentrations on the growth of PGPR. GNPs were synthesized chemically, by reduction of HAuCl4, and further characterized by UV-Vis spectroscopy, X-ray diffraction technique (XRD), and transmission electron microscopy (TEM), etc. The impact of GNPs on PGPR was investigated by Clinical Laboratory Standards Institute (CLSI) recommended Broth-Microdilution technique against four selected PGPR viz., Pseudomonas fluorescens, Bacillus subtilis, Paenibacillus elgii, and Pseudomonas putida. Neither accelerating nor reducing impact was observed in P. putida due to GNPs. On the contrary, significant increase was observed in the case of P. fluorescens, P. elgii, and B. subtilis, and hence, GNPs can be exploited as nano-biofertilizers.

Copper oxide nanoparticles: an antidermatophytic agent for Trichophyton spp.

Abstract Copper oxide (CuO) is one of the most important transition metal oxides due to its unique properties. It is used in various technological applications such as high critical temperature, superconductors, gas sensors, in photoconductive applications and so on. Recently, it has been used as an antimicrobial agent against various pathogenic bacteria. In the present investigation, we studied the structural and antidermatophytic properties of CuO nanoparticles (NPs) synthesized by a precipitation technique. Copper sulfate was used as a precursor and sodium hydroxide as a reducing agent. Scanning electron microscopy (SEM) showed flower-shaped CuO NPs and X-ray diffraction (XRD) pattern showed the crystalline nature of CuO NPs. These NPs were evaluated against two prevalent species of dermatophytes, i.e. Trichophyton rubrum and T. mentagrophytes by using the broth microdilution technique. Further, the NPs activity was also compared with synthetic sertaconazole. Although better antidermatophytic activity was exhibited with sertaconazole as compared to NPs, being synthetic, sertaconazole may not be preferred, as it shows different adverse effects. Trichophyton mentagrophytes is more susceptible to NPs than T. rubrum. A phylogenetic approach was applied for predicting differences in susceptibility of pathogens.

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.

A comparative analysis of in vitro growth inhibition of waterborne bacteria with bioactive plant Lippia nodiflora L. and camphor

AbstractIn the current scenario, due to global deterioration of the environment and climate change, among them water pollution possesses serious threat to most of the populace. Waterborne pathogenic bacteria like Escherichia coli, Vibrio cholerae, Salmonella typhimurium, Klebsiella pneumoniae, etc. are responsible for several diseases such as diarrhoea, cholera, salmonellosis, etc. In order to overcome these waterborne bacterial diseases and for purification of water, plants have been of great use for their potential role from very ancient times. The present study deals with the Clinical & Laboratory Standards Institute (CLSI)-recommended broth microdilution antibacterial susceptibility assay of waterborne bacterial pathogens against Lippia nodiflora L. petroleum ether (LNPE) and ethanolic extracts (LNEE) prepared from the leaves and flowers together of Lippia nodiflora (Verbenaceae), in comparison to camphor. Growth inhibition of tested bacterial pathogens was recorded in from of IC50 and MIC values were...

In vitro evaluation of antidermatophytic activity of five lichens

Abstract Lichens (a composite organism) are known for their secondary metabolites and have several properties as photoprotection, allelopathy, antioxidant, antimicrobial, and antiviral. In this study, based on alarming situation of prevalence and developing resistance in dermatophytes, the new biological source in the form of lichens was screened for their antidermatophytic potential. Three dermatophytes viz. Microsporum canis, Trichophyton mentagrophytes, and Trichophyton rubrum were procured from Microbial Type Cell Culture, Chandigarh, India and susceptibility of aforementioned pathogens were tested via Clinical Laboratory and Standard Institute recommended broth microdilution procedure for filamentous fungi. Five lichens viz. Bulbothrix setschwanensis, Myelochroa aurulenta, Parmotrema nilgherrense, Parmotrema reticulatum, and Ramalina conduplicans were tested for their antidermatophytic activity (fungistatic and fungicidal concentrations) in the form of MIC and MFC values. M. aurulenta exhibited most promising MIC and MFC values against all dermatophytes and provides new leads in the form of secalonic acid A and leucotylic acid for future investigations.

Introduction of Nanotechnology in the Field of Biofuel Production

Nanotechnology has an increasingly large impact on a wide range of industries, but its current use in the production of electricity and heat from biomass is limited. The potential impact of nanotechnology on bioenergy production through a literature review and interviews with industry members. Current technologies and methods in use were reviewed, with a focus on fuel handling and combustion systems. Areas in which problems existed were identified and nanotechnologies with properties relevant to those problems were examined. Basic economic analyses were also performed to determine the conditions for the economic viability of the nanotechnology solutions. Biodiesel can be used as a substitute for fossil fuels and successful studies have been carried out in different applications. Butchery wastes were used for the production of hydrocarbon gases and biodiesel. The economics of this novel process is much more cost competitive due to the cheap raw material (butchery waste) that contains high levels of fatty acids. Photocatalysis gave hydrocarbons of prime importance. The study reported an interesting finding that butchery waste could be used for not only the production of biodiesel but also for hydrocarbons. This technology differs from others in that it uses low energy input, cheap and reusable catalyst, with low sulfur and nitrogenous waste gases than petro-diesel and is environment-friendly.

Exploring Application of Nanoparticles in Production of Biodiesel

In spite of the limited sources of fossil fuels, energy demand has been considerably increased since the last century. The problems associated with global warming due to rising atmospheric greenhouse gas levels and scarcity of fossil fuels make it imperative to reduce our heavy dependency on fossil fuels. These reasons forced countries throughout the world to search for new fuel alternatives. Biofuel have gathered considerable attention due to their inherent benefits, like lower greenhouse gas emission, renewability, and sustainability. Commercially, biofuels are produced from vegetable oils, animal fats, and carbohydrates by using transesterification and fermentation. However, biofuel production suffers from high production costs and other technical barriers. Considering the environmental and economic issues, use of nanotechnology seems to be a viable solution. The rapidly depleting energy resources is the greatest challenge that the world is currently facing and mankind is forced towards exploring the various alternatives that are available to meet the rising energy demands. Biofuel is one of the alternative sources of energy and is basically the energy stored in materials that is made with the help of living things. To improve the biodiesel production rate nanocatalysts and nanomaterial bound microbial enzymes are used and on the other hand, several types and kinds of nanomaterial additives are used to increase the biogas production yield. On the basis of various review studied, it was found that the lipase enzyme from Pseudomonas cepacia were relatively more efficient in the production of biodiesel.

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.

Synthesis and antimicrobial effects of colloidal gold nanoparticles against prevalent waterborne bacterial pathogens

Abstract Gold is being used therapeutically since 2500 BC in Chinese medical history. Red colloidal gold is still used in the Indian Ayurvedic medicine for rejuvenation and revitalization during old age under the name of Swarna Bhasma. The present research describes a more reliable method for assaying growth inhibition of some waterborne bacterial pathogens by gold nanoparticles. The gold nanoparticles were synthesized by chemical method using auric chloride as a precursor salt and sodium citrate as a reducing as well as stabilizing agent. Characterization of Au NPs was performed using UV–Vis, X-ray diffraction (XRD) and TEM (transmission electron microscope). Further, these nanoparticles were tested against four well-explored waterborne bacterial pathogens viz., E. coli, V. cholerae, S. typhimurium, S. dysenteriae, using globally accepted broth microdilution method recommended by CLSI, which exhibited a good antibacterial potency demonstrated in the form of IC50 and MIC. Subsequently, a novel phylogenetic approach for reducing the cost of experimentation was also carried out. In future, Au NPs can be used in making a water purifier system or kit.