Role of metal-nanoparticles in farming practices: an insight.

Nanotechnology introduces revolutionary approaches for agriculture in the form of nano-based pesticides, fertilizers, sensors, weed-controlling agents, enhanced seed germination materials, etc. Even though metal-nanoparticles (NPs) have shown their potential to improve crop yield, the mode of action at the cellular level and fate in the human body and the environment are not well understood yet. Several metal-nanoparticles have been studied extensively by researchers for their active role in enhancing the rate of seed germination and crop quality augmentation which may happen due to several mechanisms such as increased porosity in nano-primed seeds inducing up-regulation of the expression of aquaporin and Reactive Oxygen Species (ROS) genes involved in water uptake, improving the root dehydrogenase activity to enhance the water absorption capability, etc. However, researchers have also demonstrated and reported the possible toxicity of NPs in the environment due to their agricultural practices. But the fate of NPs and their environmental impact are still unclear and largely vary based on several factors such as the size of NPs, coating material, mode of discharge and locations, etc. This review thoroughly focuses on the mode of action of various NPs in seed germination and accumulation, translocation through cells, and potential environmental and health risks.

Spatio-temporal diversity of biological aerosols over Northeast India: a metagenomic approach.

Northeast India is considered as one of the major biodiversity hotspots in the world, but the region is underexplored for their microbial biodiversity. Extensive characterization of biological aerosol (bioaerosol) samples collected from various locations of Northeast India was carried out for all four seasons in a year. These were characterized in terms of their constituents, such as pollens, fungal spores, animal debris, and non-biological components, and particulate matters, such as inhalable, thoracic, and alveolic, and finally, the bacterial diversity was determined by DNA-based metagenomic approach. The non-biological (non-viable) component of aerosols is found to vary from 30 to 89% in the pre-monsoon season, which coexists with pollens (4-20%), animal debris (1-24%), and fungal spores (1-17%). The highest number of culturable microbial populations in terms of CFU count was observed in the pre-monsoon samples (i.e., 125.24-632.45 CFU/m3), and the lowest CFU was observed in monsoon season (i.e., 20.83-319.0 CFU/m3). The metagenomic approach with the samples collected during pre-monsoon season showed a total of bacterial 184 OTUs (operational taxonomic units) with 28,028 abundance count comprising 7 major phylum, 6 classes, 10 orders, 15 families, 13 genus, and 8 species of bacteria. The species-level distribution clearly shows the presence of Gammaproteobacteria (52%) most abundantly, followed by Bacilli (21%), Alphaproteobacteria (14%), Betaproteobacteria (5%), Flavobacteria (5%), and Sphingobacteria (3%). It is the first report from the entire Northeast India to uncover spatio-temporal distribution of biological components and bacterial diversity in aerosol samples through a DNA-based metagenomic approach.

Bioremediation of motor oil-contaminated soil and water by a novel indigenous Pseudomonas otitidis strain DU13 and characterization of its biosurfactant.

Production of biosurfactant by a novel indigenous isolate Pseudomonas otitidis strain DU13 and its role in bioremediation of petroleum hydrocarbon is reported. The identity of the isolate was confirmed by 16S rDNA gene sequencing analysis (Genbank accession: MK177190). The biosurfactant produced by the isolate could reduce the surface tension of petroleum supplemented medium by 46% just after 7 days of treatment. The emulsification index (E 24 ) of the surfactant was found 37, 35, and 20%, respectively, against used motor oil, diesel, and kerosene. The FTIR spectrum of the crude biosurfactant showed the presence of υC-H stretch, υCH2, υ-C=C stretch and υC-H bonding. The isolated strain could degrade 26% of TPH content of used motor oil in liquid culture. Whereas, ex situ pilot-scale field trial demonstrated very high bioremediation potential of the isolate in terms of germination rate of Vigna radiata and Cicer arietinum seeds and plant growth just after 20 days of treatment.

Potential anti-viral activity of approved repurposed drug against main protease of SARS-CoV-2: an in silico based approach.

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) which was first reported in Wuhan province of China, has become a deadly pandemic causing alarmingly high morbidity and mortality. In the absence of new targeted drugs and vaccines against SARS-CoV-2 at present, the choices for effective treatments are limited. Therefore, considering the exigency of the situation, we focused on identifying the available approved drugs as potential inhibitor against the promising Coronavirus drug target, the Main Protease, using computer-aided methods. We created a library of U. S. Food and Drug Administration approved anti-microbial drugs and virtually screened it against the available crystal structures of Main Protease of the virus. The study revealed that Viomycin showed the highest -CDocker energy after docking at the active site of SARS-CoV-2 Main Protease. It is noteworthy that Viomycin showed higher -CDocker energy as compared to the drugs currently under clinical trial for SARS-CoV-2 treatment viz. Ritonavir and Lopinavir. Additionally, Viomycin formed higher number of H-bonds with SARS-CoV-2 Main Protease than its co-crystallised inhibitor compound N3. Molecular dynamics simulation further showed that Viomycin embedded deeply inside the binding pocket and formed robust binding with SARS-CoV-2 Main Protease. Therefore, we propose that Viomycin may act as a potential inhibitor of the Main Protease of SARS-CoV-2. Further optimisations with the drug may support the much-needed rapid response to mitigate the pandemic.Communicated by Ramaswamy H. Sarma.

Accumulating Impact of Smoking and Co-morbidities on Severity and Mortality of COVID-19 Infection: A Systematic Review and Meta-analysis.

Background: High prevalence, severity, and formidable morbidity have marked the recent emergence of the novel coronavirus disease (COVID-19) pandemic. The significant association with the pre-existing co-morbid conditions has increased the disease burden of this global health emergency, pushing the patients, healthcare workers and facilities to the verge of complete disruption. Methods: Meta-analysis of pooled data was undertaken to assess the cumulative risk assessment of multiple co-morbid conditions associated with severe COVID-19. PubMed, Scopus, and Google Scholar were searched from January 1st to June 27th 2020 to generate a well-ordered, analytical, and critical review. The exercise began with keying in requisite keywords, followed by inclusion and exclusion criteria, data extraction, and quality evaluation. The final statistical meta-analysis of the risk factors of critical/severe and non-critical COVID-19 infection was carried out on Microsoft Excel (Ver. 2013), MedCalc (Ver.19.3), and RevMan software (Ver.5.3). Results: We investigated 19 eligible studies, comprising 12037 COVID-19 disease patients, representing the People's Republic of China (PRC), USA, and Europe. 18.2% (n = 2200) of total patients had critical/severe COVID-19 disease. The pooled analysis showed a significant association of COVID-19 disease severity risk with cardiovascular disease (RR: 3.11, p < 0.001), followed by diabetes (RR: 2.06, p < 0.001), hypertension (RR: 1.54, p < 0.001), and smoking (RR: 1.52, p < 006). Conclusion: The review involved a sample size of 12037 COVID-19 patients across a wide geographical distribution. The reviewed reports have focussed on the association of individual risk assessment of co-morbid conditions with the heightened risk of COVID-19 disease. The present meta-analysis of cumulative risk assessment of co-morbidity from cardiovascular disease, diabetes, hypertension, and smoking signals a novel interpretation of inherent risk factors exacerbating COVID-19 disease severity. Consequently, there exists a definite window of opportunity for increasing survival of COVID-19 patients (with high risk and co-morbid conditions) by timely identification and implementation of appropriately suitable treatment modalities.

A Simple Work-Up-free, Solvent-free Approach to Novel Amino Acid Linked 1,4-Disubstituted 1,2,3-Triazoles as Potent Antituberculosis Agents.

An efficient, green strategy for synthesis of 1,4-disubstituted-1,2,3-triazole has been developed using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) acetate ionic liquid (200 µL) under a solvent- and external base-free condition. This protocol is further applied for the synthesis of novel amino acid containing 1,2,3-triazole molecules, which were then evaluated for potential antitubercular and antibacterial activities. Cytotoxicity assay of the compounds was also performed. In silico analysis of the promising compounds selected through experimental analysis was thereafter performed for visualizing molecular interactions and predicting binding affinities between our synthesized molecules, which exhibited good activity in experimental studies and the DprE1 target protein of Mycobacterium tuberculosis. Durg-likeness studies also show potential of the synthesized molecules as drug candidates.

Antimicrobial activity of silver nanoparticles synthesised by using microbial biosurfactant produced by a newly isolated Bacillus vallismortis MDU6 strain.

Microbial biosurfactants has evolved as green molecules and their chemical diversity has gained momentum in recent time not only in the field of environmental and industrial sectors but also in the pharmaceutical sector. In this study, an effort was made for the biosynthesis of silver nanoparticle (AgNPs) having antimicrobial and non-cytotoxic activities with the help of microbial biosurfactant extracted from a novel Bacillus vallismortis strain MDU6 (Genbank accession no. MH382951) from petroleum oil logged soil sample in Dibrugarh, Assam. The isolate shows excellent potential for the production of biosurfactant by reducing the surface tension of diesel supplemented medium up to 56.57% only within 5 days. FTIR spectra of the crude biosurfactant show the presence of ʋCH2 (asymmetric stretching), ʋCH2 (symmetric stretching), ʋC=C (stretch), ʋC-C (stretch), ʋC-H (bending), ʋC-O (stretch) and ʋC-H (bending) functional groups and LC-MS/MS analysis confirms it as a cyclic lipopeptide which is a mixture of surfactin and iturin. The synthesized AgNPs showed excellent antimicrobial activities against Escherichia coli (ATCC no. 25922), Listeria monocytogenes (ATCC No. BAA-751), Staphylococcus aureus (ATCC No. 9542) and Bacillus subtilis (ATCC no. 6051) and showed no cytotoxicity against primary mouse liver cell lines.

A newly isolated strain of Serratia sp. from an oil spillage site of Assam shows excellent bioremediation potential.

A hydrocarbon-degrading strain was isolated from a petroleum oil-contaminated site which was identified on the basis of 16S rDNA gene sequencing as a member of the genus Serratia. The isolate reduced surface tension of petroleum oil supplemented medium by 48.35% with respect to control after 7 days of treatment. Fluorescence microscopy revealed that its chemotaxis was towards hydrocarbon. The isolate degraded 87.54 and 85.48% of diesel and kerosene in liquid culture, respectively, after 28 day incubation at 37 ± 2 °C. The ex situ pilot scale bioremediation experiment in which artificially contaminated soil (10 and 20% v/w kerosene) was treated for 7 days showed a germination rate of Vigna radiate seeds of 52% and 72%, respectively. Interestingly, a germination rate of 31% was obtained with the heavily contaminated soil samples collected from the oil spillage site after 20 days of bioremediation treatment. The presence of υCH3 (asymmetric stretching), υC=C (stretch), and υC-C (stretch) in the crude biosurfactant produced by the isolate was revealed by FTIR analysis, and emulsification index (E 24) was found 60 and 56.6%, respectively, against diesel and kerosene oil. The non-cytotoxicity nature of the biosurfactant also supports its potential application in field trial.

Characterization of a Newly Isolated Probiotic Strain from Oecophylla smaragdina, an Edible Insect Popular Among the Indigenous Communities of Northeast India.

Northeast India is amongst the 34 Biodiversity Hot Spots of the world with large number of unexplored flora and fauna. A total of 74 potential isolates with probiotic properties were isolated from Oecophylla smaragdina, an edible insect used by local tribes as a nutritious medicinal food source out of which, the most potential probiotic candidate was identified as Bacillus sp. PD6 by 16S rRNA sequencing. Cell surface trait analysis shows hydrophobicity and auto-aggregation percentage of 46.2 ± 0.32% and 61.41 ± 0.28% respectively. The cell free extract (CFE) of the isolate shows the presence of essential amino acids viz, lysine, valine, leucine, isoleucine, and threonine indicating its nutritional value. It survives significantly at pH range from 1 to 10 and capable of hydrolyzing bile salt. The CFE shows antagonistic effect against B. cereus ATCC 11778, E. coli ATCC 25922 and L. monocytogenes ATCC BAA751. FTIR spectra of bacterial exo-polysaccharide shows the presence of νC=C-H stretch, νN-H stretch, νC-H stretch, νC-H bending and νC=O stretch bonds. It was found to be non-cytotoxic against primary mouse liver cell line and sheep erythrocytes and also, sensitive against wide range of broad and narrow spectrum antibiotics making it recommendable for human consumption.

Biogenic synthesis of palladium nanoparticles and their applications as catalyst and antimicrobial agent.

This paper describes a simple in-situ process of synthesizing highly dispersed palladium nanoparticles (PdNPs) using aqueous leaf extract of GarciniapedunculataRoxb as bio-reductant and starch (0.3%) as bio-stabilizer. The PdNPs are characterized by techniques like FTIR, TEM, SEM-EDX, XRD and XPS analysis. It is worthnoting thatwhen the synthesis of nanoparticles was carried out in absence of starch, agglomeration of particles has been noticed.The starch-assisted PdNPs showed excellent aqueous-phase catalytic activities for three important reactions: the Suzuki-Miyaura cross-coupling reactions of aryl halides (aryl bromides and iodides) with arylboronic acids; selective oxidations of alcohols to corresponding carbonyl compounds; and reduction of toxic Cr(VI) to nontoxic Cr(III). Our catalyst could be reused up to four cycles without much compromising with its activity. Furthermore, the material also demonstrated excellent antimicrobial and anti-biofilm activities against a novel multidrug resistant clinical bacterial isolate Cronobactersakazakii strain AMD04. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of PdNPswere found to be 0.06 and 0.12 mM respectively.