From biotechnology principles to functional and low-cost metallic bionanocatalysts

Chemical, physical and mechanical methods of nanomaterial preparation are still regarded as mainstream methods, and the scientific community continues to search for new ways of nanomaterial preparation. The major objective of this review is to highlight the advantages of using green chemistry and bionanotechnology in the preparation of functional low-cost catalysts. Bionanotechnology employs biological principles and processes connected with bio-phase participation in both design and development of nano-structures and nano-materials, and the biosynthesis of metallic nanoparticles is becoming even more popular due to; (i) economic and ecologic effectiveness, (ii) simple one-step nanoparticle formation, stabilisation and biomass support and (iii) the possibility of bio-waste valorisation. Although it is quite difficult to determine the precise mechanisms in particular biosynthesis and research is performed with some risk in all trial and error experiments, there is also the incentive of understanding the exact mechanisms involved. This enables further optimisation of bionanoparticle preparation and increases their application potential. Moreover, it is very important in bionanotechnological procedures to ensure repeatability of the methods related to the recognised reaction mechanisms. This review, therefore, summarises the current state of nanoparticle biosynthesis. It then demonstrates the application of biosynthesised metallic nanoparticles in heterogeneous catalysis by identifying the many examples where bionanocatalysts have been successfully applied in model reactions. These describe the degradation of organic dyes, the reduction of aromatic nitro compounds, dehalogenation of chlorinated aromatic compounds, reduction of Cr(VI) and the synthesis of important commercial chemicals. To ensure sustainability, it is important to focus on nanomaterials that are capable of maintaining the important green chemistry principles directly from design inception to ultimate application.     

A Mycobacterial Phosphoribosyltransferase Promotes Bacillary Survival by Inhibiting Oxidative Stress and Autophagy Pathways in Macrophages and Zebrafish

Mycobacterium tuberculosis employs various strategies to modulate host immune responses to facilitate its persistence in macrophages. The M. tuberculosis cell wall contains numerous glycoproteins with unknown roles in pathogenesis. Here, by using Concanavalin A and LC-MS analysis, we identified a novel mannosylated glycoprotein phosphoribosyltransferase, encoded by Rv3242c from M. tuberculosis cell walls. Homology modeling, bioinformatic analyses, and an assay of phosphoribosyltransferase activity in Mycobacterium smegmatis expressing recombinant Rv3242c (MsmRv3242c) confirmed the mass spectrometry data. Using Mycobacterium marinum-zebrafish and the surrogate MsmRv3242c infection models, we proved that phosphoribosyltransferase is involved in mycobacterial virulence. Histological and infection assays showed that the M. marinum mimG mutant, an Rv3242c orthologue in a pathogenic M. marinum strain, was strongly attenuated in adult zebrafish and also survived less in macrophages. In contrast, infection with wild type and the complemented ΔmimG:Rv3242c M. marinum strains showed prominent pathological features, such as severe emaciation, skin lesions, hemorrhaging, and more zebrafish death. Similarly, recombinant MsmRv3242c bacteria showed increased invasion in non-phagocytic epithelial cells and longer intracellular survival in macrophages as compared with wild type and vector control M. smegmatis strains. Further mechanistic studies revealed that the Rv3242c- and mimG-mediated enhancement of intramacrophagic survival was due to inhibition of autophagy, reactive oxygen species, and reduced activities of superoxide dismutase and catalase enzymes. Infection with MsmRv3242c also activated the MAPK pathway, NF-κB, and inflammatory cytokines. In summary, we show that a novel mycobacterial mannosylated phosphoribosyltransferase acts as a virulence and immunomodulatory factor, suggesting that it may constitute a novel target for antimycobacterial drugs.     

Regeneration of commercial nucleic acid extraction columns without the risk of carryover contamination

Nucleic acid extraction is a basic requirement in a molecular biology laboratory. In terms of purity and yield, commercial nucleic acid extraction columns are superior; however they are expensive. We report here an efficient strategy to regenerate diverse commercial columns for several rounds without altering the binding capacity of the columns or changing the properties of the nucleic acids purified. Plasmids purified with regenerated columns were functionally identical in super-coiled nature, restriction analysis, expression of the encoded reporter genes, or amplification of the viral RNA in real-time PCR. To ensure that the regenerated columns were free of the residual DNA, we used two different plasmids with different drug-resistance markers. By colony plating and PCR amplification of the encoded genes, we show that the regeneration process is absolute. Using radiolabeled DNA, we demonstrate that DNA exposed to the regeneration reagent is fragmented to molecular weight below 36 bp. Our data collectively prove regeneration of the commercial columns without the concern of carryover contamination. A procedure to permit safe and efficient regeneration of the commercial columns is not only of great advantage to extend the lifetime of these columns but also makes them commercially more affordable, especially in a resource-poor setting.     

Discovery of novel dialkyl substituted thiophene inhibitors of HCV by in silico screening of the NS5B RdRp

A novel 5,4-dialkyl substituted thiophene was discovered by in silico screening of the 3D polymerase crystal structure (1GX6) that demonstrated single digit micromolar HCV inhibition activity in the replicon assay and dose-dependent inhibition in the replicase complex assay. Subsequently, SAR was explored with a small set of dialkyl and tetrahydro-benzo thiophenes. Since these thiophenes inhibit synthesis of both, single- and double-stranded RNAs, their mechanism of action is distinct from other known HCV inhibitors.     

Evaluating the potential for reintroducing the endangered wild water buffalo (Bubalus arnee) in Kanha National Park,central India

Reintroducing megafauna to their historic range is an effective strategy to halt their extinctions and restore ecosystems. Wild water buffalo (Bubalus arnee) is an endangered megaherbivore that is lost from 95% of its range. About 90% of its global population (less than 4000) resides within India, in two isolated populations: northeast and central India. The central Indian population is on the verge of extinction and warrants urgent conservation interventions. We assess the potential and provide a strategy for reintroducing buffaloes in Kanha National Park, India. Habitat suitability using the global occurrence of buffalo revealed low-lying grasslands with least human pressure found in Kanha (390 km²) to be suitable. Within this suitable range, we evaluated vegetation composition, forage biomass, and potential carrying capacity. Multidimensional ordination classified these suitable sites into moist and dry grassland clusters. Moist grasslands were found to better suit reintroduction due to lower grazing pressure, higher productivity, and availability of perennial water sources. Distinct matriarchal clades of swamp and river buffalo were observed. Within the river buffalo clade, Indian wild buffaloes formed a distinct cluster with close proximity between northeast and central Indian samples, suggesting northeast buffaloes could be sourced for a founding population in Kanha. Following IUCN guidelines, we discuss the reintroduction strategy that could sustain approximately 200 buffaloes in the area and subsequently expand to other suitable habitats in central India. If implemented as proposed, recovery of this lost ecosystem engineer will help to restore grasslands, and swamp habitats, as well as contribute to its global conservation efforts.     

Barcoded Asaia bacteria enable mosquito in vivo screens and identify novel systemic insecticides and inhibitors of malaria transmission

This work addresses the need for new chemical matter in product development for control of pest insects and vector-borne diseases. We present a barcoding strategy that enables phenotypic screens of blood-feeding insects against small molecules in microtiter plate-based arrays and apply this to discovery of novel systemic insecticides and compounds that block malaria parasite development in the mosquito vector. Encoding of the blood meals was achieved through recombinant DNA-tagged Asaia bacteria that successfully colonised Aedes and Anopheles mosquitoes. An arrayed screen of a collection of pesticides showed that chemical classes of avermectins, phenylpyrazoles, and neonicotinoids were enriched for compounds with systemic adulticide activity against Anopheles. Using a luminescent Plasmodium falciparum reporter strain, barcoded screens identified 48 drug-like transmission-blocking compounds from a 400-compound antimicrobial library. The approach significantly increases the throughput in phenotypic screening campaigns using adult insects and identifies novel candidate small molecules for disease control.

This study presents a barcoding strategy that enables high-throughput phenotypic screens of blood-feeding insects against small molecules in microtiter plate-based arrays and applies this to the discovery of novel systemic insecticides and compounds that block malaria parasite development in the mosquito vector.     

Role of nanotechnology in agriculture with special reference to management of insect pests

Nanotechnology is a promising field of interdisciplinary research. It opens up a wide array of opportunities in various fields like medicine, pharmaceuticals, electronics and agriculture. The potential uses and benefits of nanotechnology are enormous. These include insect pests management through the formulations of nanomaterials-based pesticides and insecticides, enhancement of agricultural productivity using bio-conjugated nanoparticles (encapsulation) for slow release of nutrients and water, nanoparticle-mediated gene or DNA transfer in plants for the development of insect pest-resistant varieties and use of nanomaterials for preparation of different kind of biosensors, which would be useful in remote sensing devices required for precision farming. Traditional strategies like integrated pest management used in agriculture are insufficient, and application of chemical pesticides like DDT have adverse effects on animals and human beings apart from the decline in soil fertility. Therefore, nanotechnology would provide green and efficient alternatives for the management of insect pests in agriculture without harming the nature. This review is focused on traditional strategies used for the management of insect pests, limitations of use of chemical pesticides and potential of nanomaterials in insect pest management as modern approaches of nanotechnology.     

Chromosome catastrophes involve replication mechanisms generating complex genomic rearrangements

Complex genomic rearrangements (CGRs) consisting of two or more breakpoint junctions have been observed in genomic disorders. Recently, a chromosome catastrophe phenomenon termed chromothripsis, in which numerous genomic rearrangements are apparently acquired in one single catastrophic event, was described in multiple cancers. Here, we show that constitutionally acquired CGRs share similarities with cancer chromothripsis. In the 17 CGR cases investigated, we observed localization and multiple copy number changes including deletions, duplications, and/or triplications, as well as extensive translocations and inversions. Genomic rearrangements involved varied in size and complexities; in one case, array comparative genomic hybridization revealed 18 copy number changes. Breakpoint sequencing identified characteristic features, including small templated insertions at breakpoints and microhomology at breakpoint junctions, which have been attributed to replicative processes. The resemblance between CGR and chromothripsis suggests similar mechanistic underpinnings. Such chromosome catastrophic events appear to reflect basic DNA metabolism operative throughout an organism's life cycle.