Wildfire-induced pollution and its short-term impact on COVID-19 cases and mortality in California.

Globally, wildfires have seen remarkable increase in duration and size and have become a health hazard. In addition to vegetation and habitat destruction, rapid release of smoke, dust and gaseous pollutants in the atmosphere contributes to its short and long-term detrimental effects. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has emerged as a public health concern worldwide that primarily target lungs and respiratory tract, akin to air pollutants. Studies from our lab and others have demonstrated association between air pollution and COVID-19 infection and mortality rates. However, current knowledge on the impact of wildfire-mediated sudden outburst of air pollutants on COVID-19 is limited. In this study, we examined the association of air pollutants and COVID-19 during wildfires burned during August-October 2020 in California, United States. We observed an increase in the tropospheric pollutants including aerosols (particulate matter [PM]), carbon monoxide (CO) and nitrogen dioxide (NO2) by approximately 150%, 100% and 20%, respectively, in 2020 compared to the 2019. Except ozone (O3), similar proportion of increment was noticed during the peak wildfire period (August 16 - September 15, 2020) in the ground PM2.5, CO, and NO2 levels at Fresno, Los Angeles, Sacramento, San Diego and San Francisco, cities with largest active wildfire area. We identified three different spikes in the concentrations of PM2.5, and CO for the cities examined clearly suggesting wildfire-induced surge in air pollution. Fresno and Sacramento showed increment in the ground PM2.5, CO and NO2 levels, while San Diego recorded highest change rate in NO2 levels. Interestingly, we observed a similar pattern of higher COVID-19 cases and mortalities in the cities with adverse air pollution caused by wildfires. These findings provide a logical rationale to strategize public health policies for future impact of COVID-19 on humans residing in geographic locations susceptible to sudden increase in local air pollution.

Determination of lansoprazole in pharmaceuticals using flow injection with rhodamine 6G-diperiodatoargentate(III) chemiluminescence detection.

A chemiluminescence (CL) method based on rhodamine 6G (R6G)-diperiodatoargentate(III) (silver(III) complex) reaction in acid solution is reported for the determination of lansoprazole (LNP) combined with a flow injection (FI) technique. The most likely mechanism for CL reaction was elucidated considering reported data, spectrophotometric and spectrofluorimetric studies. The weak CL reaction between R6G and silver(III) complex could be magnanimously increased in the presence of LNP with a limit of detection (LOD) of 0.002 mg L-1 (S/N = 3), a linear range of 0.01 to 10 mg L-1 (R2 = 0.9997, n = 7), a relative standard deviation (RSD) of 1.2 to 3.2% (n = 4) and an injection throughput of 140 h-1 . No interference activity of commonly found excipients in LNP was detected. After LNP extraction from pharmaceutical samples, the recovery rate ranging from 93 to 110% (RSD, 1.4-3.3%, n = 4) was calculated. The results of the proposed flow CL method were assessed with a spectrophotometric approach applying paired Student's t-test and the calculated value (0.178) was lower than the distributed value (2.20) at a 95% confidence limit.

Effect of Y50H and S187G substitutions on thermostability and exonuclease activity of TK1646 from Thermococcus kodakarensis.

TK1646 is a highly thermostable single strand specific 3'-5' exonuclease. Exonucleases play important role in maintaining the genome integrity at elevated temperatures. Therefore, it is important to examine the factors contributing to thermostability of these exonucleases. In this study we report on production, purification and characterization of S187G and Y50H mutants of TK1646, focusing on the factors leading to thermostability of TK1646. Characterization of the recombinant proteins indicated that these substitutions did not drastically affect the catalysis of single stranded DNA. However, both of these substitutions reduced the thermostability of the recombinant proteins. Half-lives of Y50H and S187G mutants were 95 and 155 min, respectively, at 100 °C in comparison to 180 min of the wild type. Bioinformatics analysis indicated an increase in solvent accessibility of the mutated residues and disruption of hydrogens bonds. Molecular modelling and superimposition of the 3D structures of the mutants and the wild type demonstrated that one of the active site residues, Glu145, was shifted away from the metal ion in both the mutants which may be responsible for the decrease in catalytic activity. Compact secondary structure, hydrophobicity and hydrogen bonding might be the major factors contributing to the thermostability of TK1646.

Molecular characterization of a highly efficient and thermostable phosphoribosyl anthranilate isomerase from Geobacillus thermopakistaniensis.

Phosphoribosyl anthranilate isomerase is involved in the isomerization of phosphoribosyl anthranilate to 1-(o-carboxyphenylamino)-1-deoxyribulose 5-phosphate. In the present study, trpFGt, a gene encoding phosphoribosyl anthranilate isomerase from Geobacillus thermopakistaniensis, was cloned and expressed in Escherichia coli. The gene product, TrpFGt, was produced in E. coli in soluble and active form. Molecular characterization revealed that recombinant TrpFGt was highly efficient and stable. The apparent Vmax and Km values were 480 µmol min-1 mg-1 and 1.15 µM, respectively. The half-life of the enzyme was 90 min at 60 °C. Apart from thermostability, TrpFGt was highly stable against protein denaturants such as urea. There was no significant change in activity even after treatment with 8 M urea. To the best of our knowledge, TrpFGt, is the most active and stable phosphoribosyl anthranilate isomerase characterized to date and this is the first characterization of TrpF from the genus Geobacillus.

Flow-injection determination of manganese (II) using surfactant enhanced diperiodatonickelate (IV)-rhodamine 6G chemiluminescence.

Chemiluminescence (CL) of the rhodamine 6-G-diperiodatonickelate (IV) (Rh6-G-Ni(IV) complex) in the presence of Brij-35 was examined in an alkaline medium and implemented using flow-injection analysis to analyze Mn(II) in natural waters. Brij-35 was identified as the surfactant of choice that enhanced CL intensity by about 62% of the reaction. The calibration curves were linear in the range 1.7 × 10-3 - 0.2 (0.9990, n = 7) and 8.0 × 10-4 - 0.1 µg ml-1 (0.9990, n = 7) with limits of detection (LODs) (S:N = 3) of 5.0 × 10-4 and 2.4 × 10-4 µg ml-1 without and with using an in-line 8-hydroxyquinoline (8-HQ) resin mini-column, respectively. The sample throughput and relative standard deviation were 200 h-1 and 1.7-2.2% in the range studied respectively. Mn(II) concentrations in certified reference materials and natural water samples was successfully determined. A brief discussion about the possible CL reaction mechanism is also given. In addition, analysis of V(III), Cr(III) and Fe(II) was also performed without and with using an in-line 8-HQ column and selective elution of each metal ion was achieved by adjusting the pH of the sample carrier stream with aqueous HCl solution.

Pcal_0632, a phosphorylating glyceraldehyde-3-phosphate dehydrogenase from Pyrobaculum calidifontis.

Genome sequence of the hyperthermophilic archaeon Pyrobaculum calidifontis contains an open reading frame, Pcal_0632, annotated as glyceraldehyde-3-phosphate dehydrogenase, which is partially overlapped with phosphoglycerate kinase. In the phylogenetic tree, Pcal_0632 clustered with phosphorylating glyceraldehyde-3-phosphate dehydrogenases characterized from hyperthermophilic archaea and exhibited highest identity of 54% with glyceraldehyde-3-phosphate dehydrogenase from Sulfolobus tokodaii. To examine biochemical function of the protein, Pcal_0632 gene was expressed in Escherichia coli and the gene product was purified. The recombinant enzyme catalyzed the conversion of glyceraldehyde 3-phosphate and inorganic phosphate into 1,3-bisphosphoglycerate utilizing both NAD and NADP as cofactor with a marked preference for NADP. The enzyme was highly stable against temperature and denaturants. Half-life of the enzyme was 60 min at 100 °C. It retained more than 60% of its activity even after an incubation of 72 h at room temperature in the presence of 6 M urea. High thermostability and resistance against denaturants make Pcal_0632 a novel glyceraldehyde-3-phosphate dehydrogenase.

Identification of a novel copper-activated and halide-tolerant laccase in Geobacillus thermopakistaniensis.

Genome search of Geobacillus thermopakistaniensis, formerly Geobacillus sp. SBS-4S, revealed the presence of an open reading frame (ESU71923) annotated as laccase. However, the gene product did not display any laccase-like activity against the substrates examined. The laccase activity was, therefore, purified from G. thermopakistaniensis cells and N-terminal amino acid residues of the enzyme were determined. These residues matched the N-terminal sequence of an open reading frame annotated as a copper oxidase (ESU72270). In order to characterize the enzyme, recombinant ESU72270 was prepared in Escherichia coli. The recombinant protein was found to exhibit a negligible amount of laccase activity when produced in the absence of copper in the growth medium. However, the recombinant protein exhibited significantly high laccase activity when produced in the presence of copper. The recombinant enzyme showed highest activity at 60 °C and a pH of 7-7.5. The purified enzyme was highly tolerant to various halides and organic solvents, thus having a potential for various industrial applications. To the best of our knowledge, this is the first characterization of a laccase from genus Geobacillus which identifies a gene responsible for functional laccase in this genus.

Truncated Type II isopentenyl diphosphate isomerase from hyperthermophilic Achaeon Thermococcus kodakaraensis implicates the necessity of its N-terminal amino acid residues in protein thermostability.

The enzyme isopentenyl diphosphate isomerase (IDI, EC 5.3.3.2) interconverts isopentenyl diphosphate and dimethylallyl diphosphate. We had previously cloned Tk-idi gene encoding the thermostable Tk-IDI enzyme from Thermococcus kodakaraensis KOD1. Four putative start codons were found on Tk-idi gene at 123, 213, 297 and 321 positions downstream of the first start codon. In the present work four mutants were obtained by deleting 123, 213, 297 and 321 nucleotides from the 5'-end of Tk-idi gene to obtain Tk-idim, Tk-idim1, Tk-idim2, and Tk-idim3, respectively. When we tried to express these truncated genes in Escherichia coli only Tk-idim was expressed in the active form. The product, Tk-IDIM, was purified and characterized. The molecular mass of the enzyme, estimated by gel filtration chromatography, was 300 kDa which indicated that the truncated enzyme retained the octameric form. The removal of 41 N-terminal amino acids did not exhibit a significant effect on the enzyme activity however, the thermostability of the enzyme decreased. The decrease in thermostability of Tk-IDIM correlated well with the results of circular dichroism (CD) analysis and structural modeling.

Monitoring built-up area expansion led by industrial transformation in Delhi using geospatial techniques.

Historically, industrialization has been a catalyst for built-up expansion generated by economic growth that transforms a landscape. In India, there is a paucity of exploration into how the economic shift transforms the cityscape. Therefore, the objective of current research work was to monitor built-up growth induced by industrialization using Landsat datasets and registered industry data. The k-means clustering technique was applied for assessing land use/land cover, Shannon entropy for sprawl, and Pearson for correlation between industrial growth and built-up expansion. The results manifest exponential trend in industrialization with 102-year registered industry record along with increase in built-up density from 0.30 in 1989 to 0.69 by 2019 and in the entire Delhi; it rose from 0.16 to 0.39. Furthermore, Shannon entropy confirmed the sprawl and the strong positive correlation was found among built-up of industrial areas and built-up of Delhi and registered industries. The striking chorological change in industrial as well as city's landscape was observed co-occurring with the dynamics of economic reforms. The outcome of current research could be utilized for the sustainable planning of industrial landscape in Delhi and cities with alike geographical conditions.

Wetland health assessment using DPSI framework: a case study in Kolkata Metropolitan Area.

Wetlands are among the most valuable components of the ecosystem, playing an important role in preventing floods, maintaining the hydrological cycle, protecting against natural hazards, and controlling local weather conditions and ecological restoration. The Kolkata Metropolitan Area (KMA) is considered one of the most ecologically valuable regions in terms of wetland ecosystem, but due to haphazard development and human activities, the wetlands of the city are under constant threat of degradation. Therefore, this study aims to assess the factors responsible for wetland health and their dynamics using Driving Force-Pressure-State-Impact (DPSI) framework. To assess wetland health during 2011-2020, seventeen indicators and four sub-indicators were selected to calculate weights using the analytic hierarchy process (AHP). The results showed that most of the municipalities in the healthy category were in the pressure (P) section in 2011, while fluctuations were observed in the impact (I) section in several wards during 2011-20. The condition section (S) showed the overall change in the water, vegetation, and built-up categories from 2011 to 2020, so the most dominant category was "healthy," followed by "unhealthy" and "poor." The highly significant factors worsening wetland health were population density (B1), road density (B3), per capita wastewater generation (B5), per capita solid waste generation (B7), biological oxygen demand (D1a), dissolved oxygen (D1b), pH (D1c), and total coliform (D1d). The results of the study can help develop sustainable conservation and management of the wetland ecosystem in the KMA urban area and at the global level with similar geographical conditions.

Analysing the role of gender and place of residence in acceptability and satisfaction towards e-learning among university students' during COVID-19 pandemic in India.

This paper has two broad objectives; the first is to examine the challenges of e-learning faced by the students keeping in view their place of residence and gender in India, particularly during the second-wave of Covid-19. The second objective is to examine the role of place of residence and gender of students in the acceptance and satisfaction towards e-learning. The data has been obtained through an online survey of the students of University of Jamia Millia Islamia, New Delhi, India, in which a total of 490 students participated. Selection of students has been done through stratified sampling technique. Initially the obtained data was analysed and discussed through simple statistical analysis. Later, a chi-square test of independence was applied to find out the dependency of psychological stress, level of acceptance and level of satisfaction towards e-learning on the place of residence and the gender. The major finding of the paper reveals that the gender and the place of residence of the students is significantly associated with their psychological stress, acceptance and satisfaction towards e-learning. Extra money spent on the purchase of online learning resources was greater in case of rural students.

Spatio-temporal analysis of air quality and its relationship with major COVID-19 hotspot places in India.

The COVID-19 pandemic spread worldwide, such as wind, with more than 400,000 documented cases as of March 24th, 2020. In this regard, strict lockdown measures were imposed in India on the same date to stop virus spread. Thereafter, various lockdown impacts were observed, and one of the immediate effects was a reduction in air pollution levels across the world and in India as well. In this study, we have observed approximately 40% reduction in air quality index (AQI) during one month of lockdown in India. The detailed investigations were performed for 14 major hotspot places where the COVID-19 cases were >1000 (as of 1st June 2020) and represents more than 70% associated mortality in India. We assessed the impact of lockdown on different air quality indicators, including ground (PM2.5, PM10, NO2, SO2, O3, and AQI) and tropospheric nitric oxide (NO2) pollutants, through ground monitoring stations and Sentinel-5 satellite datasets respectively. The highest reductions were noticed in NO2 (-48.68%), PM2.5 (-34.84%) and PM10 (-33.89%) air pollutant (unit in µg/m3) post-lockdown. Moreover, tropospheric NO2 (mol/m2) concentrations were also improved over Delhi, Mumbai, Kolkata, Thane, and Ahmedabad metro cities. We found strong positive correlation of COVID-19 mortality with PM10 (R2 = 0.145; r = 0.38) and AQI (R2 = 0.17; r = 0.412) pollutant indicators that significantly improved next time point. The correlation finding suggests that long-term bad air quality may aggravate the clinical symptoms of the disease.

Optimization of state-of-the-art fuzzy-metaheuristic ANFIS-based machine learning models for flood susceptibility prediction mapping in the Middle Ganga Plain, India.

This study is an attempt to quantitatively test and compare novel advanced-machine learning algorithms in terms of their performance in achieving the goal of predicting flood susceptible areas in a low altitudinal range, sub-tropical floodplain environmental setting, like that prevailing in the Middle Ganga Plain (MGP), India. This part of the Ganga floodplain region, which under the influence of undergoing active tectonic regime related subsidence, is the hotbed of annual flood disaster. This makes the region one of the best natural laboratories to test the flood susceptibility models for establishing a universalization of such models in low relief highly flood prone areas. Based on highly sophisticated flood inventory archived for this region, and 12 flood conditioning factors viz. annual rainfall, soil type, stream density, distance from stream, distance from road, Topographic Wetness Index (TWI), altitude, slope aspect, slope, curvature, land use/land cover, and geomorphology, an advanced novel hybrid model Adaptive Neuro Fuzzy Inference System (ANFIS), and three metaheuristic models-based ensembles with ANFIS namely ANFIS-GA (Genetic Algorithm), ANFIS-DE (Differential Evolution), and ANFIS-PSO (Particle Swarm Optimization), have been applied for zonation of the flood susceptible areas. The flood inventory dataset, prepared by collected flood samples, were apportioned into 70:30 classes to prepare training and validation datasets. One independent validation method, the Area-Under Receiver Operating Characteristic (AUROC) Curve, and other 11 cut-off-dependent model evaluation metrices have helped to conclude that the ANIFS-GA has outperformed other three models with highest success rate AUC = 0.922 and prediction rate AUC = 0.924. The accuracy was also found to be highest for ANFIS-GA during training (0.886) & validation (0.883). Better performance of ANIFS-GA than the individual models as well as some ensemble models suggests and warrants further study in this topoclimatic environment using other classes of susceptibility models. This will further help establishing a benchmark model with capability of highest accuracy and sensitivity performance in the similar topographic and climatic setting taking assumption of the quality of input parameters as constant.

Improved air quality and associated mortalities in India under COVID-19 lockdown.

India enforced stringent lockdown measures on March 24, 2020 to mitigate the spread of the Severe Acute Respiratory Syndrome Coronovirus-2 (SARS-CoV-2). Here, we examined the impact of lockdown on the air quality index (AQI) [including ambient particulate matter (PM10 and PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), ozone (O3), and ammonia (NH3)] and tropospheric NO2 and O3 densities through Sentinel-5 satellite data approximately 1 d post-lockdown and one month pre-lockdown and post-lockdown. Our findings revealed a marked reduction in the ambient AQI (estimated mean reduction of 17.75% and 20.70%, respectively), tropospheric NO2 density, and land surface temperature (LST) during post-lockdown compared with the pre-lockdown period or corresponding months in 2019, except for a few sites with substantial coal mining and active power plants. We observed a modest increase in the O3 density post-lockdown, thereby indicating improved tropospheric air quality. As a favorable outcome of the COVID-19 lockdown, road accident-related mortalities declined by 72-folds. Cities with poor air quality correlate with higher COVID-19 cases and deaths (r = 0.504 and r = 0.590 for NO2; r = 0.744 and r = 0.435 for AQI). Conversely, low mortality was reported in cities with better air quality. These results show a correlation between the COVID-19 vulnerable regions and AQI hotspots, thereby suggesting that air pollution may exacerbate clinical manifestations of the disease. However, a prolonged lockdown may nullify the beneficial environmental outcomes by adversely affecting socioeconomic and health aspects.

Surface histidine residue of archaeal histone affects DNA compaction and thermostability.

Archaeal histone, which possesses only the core domain part of eukaryal histone, induced DNA compaction by binding to DNA. Based on structural modeling, tetramer formation by dimer-dimer interaction is considered to require two intermolecular ion pairs formed between histidine and aspartate. To examine the role of the ion pairs on DNA compaction, mutant histones were constructed and analyzed using HpkB from Thermococcus kodakaraensis KOD1 as a model protein. The mutant histones, HpkB-H50A, HpkB-H50V, and HpkB-H50G were constructed by replacing conserved surface His50 with Ala, Val, and Gly, respectively. Circular dichroism analysis indicated no significant difference between wild-type and mutants in their structures. Gel mobility shift assays showed that all mutants possessed DNA binding ability, like wild-type HpkB, however all mutants compacted DNA less efficiently than the wild-type. Moreover, all mutants could not maintain the nucleosome-like structure (compacted form of DNA) above 80 degrees C. These results suggest that surface ion pairs between His and Asp play an important role in maintenance of nucleosome structure and DNA stabilization at high temperature.

An instant measurement of oxidoreductase activity above 100 degrees C by monitoring the absorbance change.

A conventional absorbance monitoring method using a cuvette covered with a tight rubber cap was found to be applicable for measuring oxidoreductase activity at temperatures up to 115 degrees C. Using this method, the optimal temperatures of the enzymes, including oxygen-sensitive enzymes from a hyperthermophilic archaeon Thermococcus profundus, were determined.

Draft Genome Sequence of Geobacillus thermopakistaniensis Strain MAS1.

Geobacillus thermopakistaniensis strain MAS1 was isolated from a hot spring located in the Northern Areas of Pakistan. The draft genome sequence was 3.5 Mb and identified a number of genes of potential industrial importance, including genes encoding glycoside hydrolases, pullulanase, amylopullulanase, glycosidase, and alcohol dehydrogenases.

Indolepyruvate ferredoxin oxidoreductase: An oxygen-sensitive iron-sulfur enzyme from the hyperthermophilic archaeon Thermococcus profundus.

Thermococcus profundus is a strictly anaerobic sulfur-dependent archaeon that grows optimally at 80°C by peptide fermentation. Indolepyruvate ferredoxin oxidoreductase (IOR), an enzyme involved in the peptide fermentation pathway, was purified to homogeneity from the archaeon under strictly anaerobic conditions. The maximal activity was obtained above the boiling temperature of water (105°C), with a half-life of 62min at 100°C and 20min at 105°C. IOR was oxygen-sensitive with a half-life of 7h at 25°C under aerobic conditions. The specific activity of T. profundus IOR was found to be dependent on the number of [4Fe-4S] clusters in the enzyme.

Antibiotic susceptibility profiling and virulence potential ofCampylobacter jejuni isolates from different sources in Pakistan

Objective:To determine antibiotic resistance patterns and virulence potential ofCampylobacter jejuni (C. jejuni) isolates from clinical human diarrheal infections, cattle and healthy broilers. Methods:Antibiotic sensitivity patterns ofC. jejuni isolates were determined by Kirby Bauer Disc Diffusion assay. These isolates were then subjected to virulence profiling for the detection ofmapA (membrane-associated protein),cadF (fibronectin binding protein),wlaN (beta-1,3-galactosyltransferase) andneuAB (sialic acid biosynthesis gene). FurtherC. jejuni isolates were grouped by random amplification of polymorphic DNA (RAPD) profiling.Results: A total of 436 samples from poultry (n=88), cattle (n=216) and humans (n=132) from different locations were collected. Results revealed percentage ofC. jejuni isolates were 35.2% (31/88), 25.0% (54/216) and 11.3% (15/132) among poultry, cattle and clinical human samples respectively. Antibiotic susceptibility results showed that similar resistance patterns to cephalothin was ie. 87.0%, 87.1% and 89%among humans, poultry and cattle respectively, followed by sulfamethoxazole+trimethoprim 40.0%, 38.7% and 31.0% in humans, poultry and cattle and Ampicillin 40%, 32% and 20% in humans, poultry and cattle respectively. Beta-lactamase activity was detected in 40.00% humans, 20.37% cattle and 32.25% in poultryC. jejuni isolates. CadF andmapA were present in all poultry, cattle and humanC. jejuni isolates,wlaN was not detected in any isolate andneuAB was found in 9/31 (36%) poultry isolates. RAPD profiling results suggested high diversity ofC. jejuni isolates.Conclusions:Detection of multidrug resistantC. jejuni strains from poultry and cattle is alarming as they can be potential hazard to humans. Moreover, predominant association of virulence factors,cadF andmapA (100 % each) inC. jejuni isolates from all sources andneuAB (36%) with poultry isolates suggest the potential source of transmission of diverse types ofC. jejuni to humans.