Cell Culture Adaptive Amino Acid Substitutions in FMDV Structural Proteins: A Key Mechanism for Altered Receptor Tropism.

The foot-and-mouth disease virus is a highly contagious and economically devastating virus of cloven-hooved animals, including cattle, buffalo, sheep, and goats, causing reduced animal productivity and posing international trade restrictions. For decades, chemically inactivated vaccines have been serving as the most effective strategy for the management of foot-and-mouth disease. Inactivated vaccines are commercially produced in cell culture systems, which require successful propagation and adaptation of field isolates, demanding a high cost and laborious time. Cell culture adaptation is chiefly indebted to amino acid substitutions in surface-exposed capsid proteins, altering the necessity of RGD-dependent receptors to heparan sulfate macromolecules for virus binding. Several amino acid substations in VP1, VP2, and VP3 capsid proteins of FMDV, both at structural and functional levels, have been characterized previously. This literature review combines frequently reported amino acid substitutions in virus capsid proteins, their critical roles in virus adaptation, and functional characterization of the substitutions. Furthermore, this data can facilitate molecular virologists to develop new vaccine strains against the foot-and-mouth disease virus, revolutionizing vaccinology via reverse genetic engineering and synthetic biology.

Punicalagin, a pomegranate polyphenol sensitizes the activity of antibiotics against three MDR pathogens of the Enterobacteriaceae.

BACKGROUND: Multidrug resistance (MDR) in the family Enterobacteriaceae is a perniciously increasing threat to global health security. The discovery of new antimicrobials having the reversing drug resistance potential may contribute to augment and revive the antibiotic arsenal in hand. This study aimed to explore the anti-Enterobacteriaceae capability of bioactive polyphenols from Punica granatum (P. granatum) and their co-action with antibiotics against clinical isolates of Enterobacteriaceae predominantly prevalent in South Asian countries. METHODS: The Kandhari P. granatum (Pakistani origin) extracts were tested for anti-Enterobacteriaceae activity by agar well diffusion assay against MDR Salmonella enterica serovar Typhi, serovar Typhimurium and Escherichia coli. Predominant compounds of active extract were determined by mass spectrometry and screened for bioactivity by agar well diffusion and minimum inhibitory concentration (MIC) assay. The active punicalagin was further evaluated at sub-inhibitory concentrations (SICs) for coactivity with nine conventional antimicrobials using a disc diffusion assay followed by time-kill experiments that proceeded with SICs of punicalagin and antimicrobials. RESULTS: Among all P. granatum crude extracts, pomegranate peel methanol extract showed the largest inhibition zones of 25, 22 and 19 mm, and the MICs as 3.9, 7.8 and 7.8 mg/mL for S. typhi, S. typhimurium and E. coli, respectively. Punicalagin and ellagic acid were determined as predominant compounds by mass spectrometry. In plate assay, punicalagin (10 mg/mL) was active with hazy inhibition zones of 17, 14, and 13 mm against S. typhi, S. typhimurium and E. coli, respectively. However, in broth dilution assay punicalagin showed no MIC up to 10 mg/mL. The SICs 30 µg, 100 µg, and 500 µg of punicalagin combined with antimicrobials i.e., aminoglycoside, ß-lactam, and fluoroquinolone act in synergy against MDR strains with % increase in inhibition zone values varying from 3.4 ± 2.7% to 73.8 ± 8.4%. In time-kill curves, a significant decrease in cell density was observed with the SICs of antimicrobials/punicalagin (0.03-60 µg/mL/30, 100, 500 µg/mL of punicalagin) combinations. CONCLUSIONS: The P. granatum peel methanol extract exhibited antimicrobial activity against MDR Enterobacteriaceae pathogens. Punicalagin, the bacteriostatic flavonoid act as a concentration-dependent sensitizing agent for antimicrobials against Enterobacteriaceae. Our findings for the therapeutic punicalagin-antimicrobial combination prompt further evaluation of punicalagin as a potent activator for drugs, which otherwise remain less or inactive against MDR strains.

Inhibition of NS2B-NS3 protease from all four serotypes of dengue virus by punicalagin, punicalin and ellagic acid identified from Punica granatum.

Despite a major threat to the public health in tropical and subtropical regions, dengue virus (DENV) infections are untreatable. Therefore, efforts are needed to investigate cost-effective therapeutic agents that could cure DENV infections in future. The NS2B-NS3 protease encoded by the genome of DENV is considered a critical target for the development of anti-dengue drugs. The objective of the current study was to find out a specific inhibitor of the NS2B-NS3 proteases from all four serotypes of DENV. To begin with, nine plant extracts with a medicinal history were evaluated for their role in inhibiting the NS2B-NS3 proteases by Fluorescence Resonance Energy Transfer (FRET) assay. Among the tested extracts, Punica granatum was found to be the most effective one. The metabolic profiling of this extract revealed the presence of several active compounds, including ellagic acid, punicalin and punicalagin, which are well-established antiviral agents. Further evaluation of IC50 values of these three antiviral molecules revealed punicalagin as the most potent anti-NS2B-NS3 protease drug with IC50 of 0.91 ± 0.10, 0.75 ± 0.05, 0.42 ± 0.03, 1.80 ± 0.16 µM against proteases from serotypes 1, 2, 3 and 4, respectively. The docking studies demonstrated that these compounds interacted at the active site of the enzyme, mainly with His and Ser residues. Molecular dynamics simulations analysis also showed the structural stability of the NS2B-NS3 proteases in the presence of punicalagin. In summary, this study concludes that the punicalagin can act as an effective inhibitor against NS2B-NS3 proteases from all four serotypes of DENV.Communicated by Ramaswamy H. Sarma.

Genomic analysis and biodesulfurization potential of a new carbon-sulfur bond cleaving Tsukamurella sp. 3OW.

Direct combustion of sulfur-enriched liquid fuel oil causes sulfur oxide emission, which is one of the main contributors to air pollution. Biodesulfurization is a promising and eco-friendly method to desulfurize a wide range of thiophenic compounds present in fuel oil. Previously, numerous bacterial strains from genera such as Rhodococcus, Corynebacterium, Gordonia, Nocardia, Mycobacterium, Mycolicibacterium, Paenibacillus, Shewanella, Sphingomonas, Halothiobacillus, and Bacillus have been reported to be capable of desulfurizing model thiophenic compounds or fossil fuels. In the present study, we report a new desulfurizing bacterium, Tsukamurella sp. 3OW, capable of desulfurization of dibenzothiophene through the carbon-sulfur bond cleavage 4S pathway. The bacterium showed a high affinity for the hydrocarbon phase and broad substrate specificity towards various thiophenic compounds. The overall genome-related index analysis revealed that the bacterium is closely related to Tsukamurella paurometabola species. The genomic pool of strain 3OW contains 57 genes related to sulfur metabolism, including the key dszABC genes responsible for dibenzothiophene desulfurization. The DBT-adapted cells of the strain 3OW displayed significant resilience and viability in elevated concentrations of crude oil. The bacterium showed a 19 and 37% reduction in the total sulfur present in crude and diesel oil, respectively. Furthermore, FTIR analysis indicates that the oil's overall chemistry remained unaltered following biodesulfurization. This study implies that Tsukamurella paurometabola species, previously undocumented in the context of biodesulfurization, has good potential for application in the biodesulfurization of petroleum oils.

Identification of additional mechanistically important residues in the multidrug transporter styMdtM of Salmonella Typhi.

Multidrug efflux is a well-established mechanism of drug resistance in bacterial pathogens like Salmonella Typhi. styMdtM (locus name; STY4874) is a multidrug efflux transporter of the major facilitator superfamily expressed in S. Typhi. Functional assays identified several residues important for its transport activity. Here, we used an AlphaFold model to identify additional residues for analysis by mutagenesis. Mutation of peripheral residue Cys185 had no effect on the structure or function of the transporter. However, substitution of channel-lining residues Tyr29 and Tyr231 completely abolished transport function. Finally, mutation of Gln294, which faces peripheral helices of the transporter, resulted in the loss of transport of some substrates. Crystallization studies yielded diffraction data for the wild-type protein at 4.5 Å resolution and allowed the unit cell parameters to be established as a = b = 64.3 Å, c = 245.4 Å, α = ß = γ = 90°, in space group P4. Our studies represent a further stepping stone towards a mechanistic understanding of the clinically important multidrug transporter styMdtM.Communicated by Ramaswamy H. Sarma.

Itraconazole Loaded Biosurfactin Micelles with Enhanced Antifungal Activity: Fabrication, Evaluation and Molecular Simulation.

Itraconazole (ITZ) is a broad-spectrum antifungal for superficial subcutaneous and systemic fungal infections. This study aimed to enhance the antifungal activity of ITZ using surfactin A (SA), a cyclic lipopeptide produced by the SA-producing Bacillus strain NH-100, possessing strong antifungal activity. SA was extracted, and ITZ-loaded SA micelles formulations were prepared via a single-pot rinsing method and characterized by particle size, zeta potential, and infrared spectroscopy. In vitro dissolution at pH 1.2, as well as hemolysis studies, was also carried out. The fabricated formulations were stable and non-spherical in shape, with an average size of about 179 nm, and FTIR spectra depicted no chemical interaction among formulation components. ITZ-loaded micelles showed decreased hemolysis activity in comparison to pure ITZ. The drug released followed the Korsmeyer-Peppas model, having R2 0.98 with the diffusion release mechanism. In an acidic buffer, drug release of all prepared formulations was in the range of 73-89% in 2 h. The molecular simulation showed the outstanding binding and stability profile of the ITZ-SA complex. The aromatic ring of the ITZ mediates a π-alkyl contact with a side chain in the SA. It can be concluded that ITZ-loaded micelles, owing to significant enhanced antifungal activity up to 6-fold due to the synergistic effect of SA, can be a promising drug delivery platform for delivery of poorly soluble ITZ.

Genomic characterization and comparative genomic analysis of HS-associated Pasteurella multocida serotype B:2 strains from Pakistan.

BACKGROUND: Haemorrhagic septicaemia (HS) is a highly fatal and predominant disease in livestock, particularly cattle and buffalo in the tropical regions of the world. Pasteurella multocida (P. multocida), serotypes B:2 and E:2, are reported to be the main causes of HS wherein serotype B:2 is more common in Asian countries including Pakistan and costs heavy financial losses every year. As yet, very little molecular and genomic information related to the HS-associated serotypes of P. multocida isolated from Pakistan is available. Therefore, this study aimed to explore the characteristics of novel bovine isolates of P. multocida serotype B:2 at the genomic level and perform comparative genomic analysis of various P. multocida strains from Pakistan to better understand the genetic basis of pathogenesis and virulence. RESULTS: To understand the genomic variability and pathogenomics, we characterized three HS-associated P. multocida serotype B:2 strains isolated from the Faisalabad (PM1), Peshawar (PM2) and Okara (PM3) districts of Punjab, Pakistan. Together with the other nine publicly available Pakistani-origin P. multocida strains and a reference strain Pm70, a comparative genomic analysis was performed. The sequenced strains were characterized as serotype B and belong to ST-122. The strains contain no plasmids; however, each strain contains at least two complete prophages. The pan-genome analysis revealed a higher number of core genes indicating a close resemblance to the studied genomes and very few genes (1%) of the core genome serve as a part of virulence, disease, and defense mechanisms. We further identified that studied P. multocida B:2 strains harbor common antibiotic resistance genes, specifically PBP3 and EF-Tu. Remarkably, the distribution of virulence factors revealed that OmpH and plpE were not present in any P. multocida B:2 strains while the presence of these antigens was reported uniformly in all serotypes of P. multocida. CONCLUSION: This study's findings indicate the absence of OmpH and PlpE in the analyzed P. multocida B:2 strains, which are known surface antigens and provide protective immunity against P. multocida infection. The availability of additional genomic data on P. multocida B:2 strains from Pakistan will facilitate the development of localized therapeutic agents and rapid diagnostic tools specifically targeting HS-associated P. multocida B:2 strains.

Duodenal ulcer perforation and its consequences.

Duodenal ulcer perforation, a frequent surgical emergency, needs simple closure with indirect Graham's Omentopexy which is effective with excellent results in majority of cases despite patients' late presentation. The objective of the study was to determine the frequency of postoperative complications of perforated duodenal ulcer, conducted in the Surgery Department, Jinnah Postgraduate Medical Centre, Karachi, from March 20, 2018 to September 20, 2018. The study was a descriptive case series of 108 patients of both genders with perforated duodenal ulcer > 1 week old with ASA score I & II. Patients with trauma and comorbidities were excluded. The patients underwent laparotomy and peritoneal toilet, and after noting the site of perforation indirect Graham's Omentopexy was performed. Complications like duodenal fistula, peritonitis, and paralytic ileus, and patient's death within 10 days of surgery were noted. Age ranged from 18 to 50 years with mean age of 35.027±5.13 years, mean weight 71.120±12.77 kg, mean height 1.541 ±0.09 metres, mean BMI 29.975±4.99 kg/m2, and the mean duration of complaint was 4.194±1.30 weeks. Male predominance in 75 (69.4%) patients. Duodenal fistula was seen in 10 (9.3%) patients, peritonitis 12 (11.1%), paralytic ileus 14 (13%) and mortality was in 11 (10.2%) patients.

In-vitro assessment of a novel plant rhizobacterium, Citrobacter freundii, for degrading and biocontrol of food mycotoxin deoxynivalenol.

Deoxynivalenol (DON) is one of the most harmful and well-known toxins present in food and animal feed throughout the world. Citrobacter freundii (C. freundii-ON077584), a novel DON-degrading strain, was isolated from rice root-linked soil samples. The degrading properties, including DON concentrations, incubation pH, incubation temperatures, bacterial concentrations, and acid treatment effect on degradation, were evaluated. At pH 7 and an incubation temperature of 37 °C, C. freundii demonstrated the capability to degrade more than 90% of DON. The degraded products of DON were identified as 3-keto-DON and DOM-1, which were confirmed by High Performance Liquid Chromatography (HPLC) and Ultra-Performance Liquid Chromatography hyphenated with Tandem Mass Spectrometry (UPLC-MS/MS) analyses. The mechanism of DON degradation into 3-keto-DON and DOM-1 by this bacterial strain will be further explored to identify and purify novel degrading enzymes that can be cloned to the microorganism and added to the animal feed to degrade the DON in the digestion tract.

Exploiting the co-crystal ligands shape, features and structure-based approaches for identification of SARS-CoV-2 Mpro inhibitors.

SARS-CoV-2 enters the host cell through the ACE2 receptor and replicates its genome using an RNA-Dependent RNA Polymerase (RDRP). The functional RDRP is released from pro-protein pp1ab by the proteolytic activity of Main protease (Mpro) which is encoded within the viral genome. Due to its vital role in proteolysis of viral polyprotein chains, it has become an attractive potential drug target. We employed a hierarchical virtual screening approach to identify small synthetic protease inhibitors. Statistically optimized molecular shape and color-based features (various functional groups) from co-crystal ligands were used to screen different databases through various scoring schemes. Then, the electrostatic complementarity of screened compounds was matched with the most active molecule to further reduce the hit molecules' size. Finally, five hundred eighty-seven molecules were docked in Mpro catalytic binding site, out of which 29 common best hits were selected based on Glide and FRED scores. Five best-fitting compounds in complex with Mpro were subjected to MD simulations to analyze their structural stability and binding affinities with Mpro using MM/GB(PB)SA models. Modeling results suggest that identified hits can act as the lead compounds for designing better active Mpro inhibitors to enhance the chemical space to combat COVID-19.Communicated by Ramaswamy H. Sarma.

Comparing Water Transport Properties of Janus Membranes Fabricated from Copper Mesh and Foam Using a Femtosecond Laser.

One of the important aspects of manipulating and controlling liquid transport is the design of membrane surfaces. Janus membranes with opposite wettability characteristics can be manufactured for efficient directional water transfer. In this work, two types of materials were used to fabricate membranes with an asymmetric wettability behavior: copper foam and copper mesh. One side of the membranes was treated by scanning with a femtosecond laser beam, as a result of which it was converted to a superhydrophilic state, while the untreated side remained hydrophobic. Both membranes demonstrated excellent properties of a water diode through which water droplets could easily pass from the hydrophobic side to the hydrophilic side, but not vice versa. This behavior was achieved by finding the optimal laser scanning speed. This type of Janus membrane has found applications in collecting water droplets from fog; therefore, the samples obtained were also tested in terms of harvesting micro-droplets. The Janus mesh-based structure has demonstrated a higher water collection efficiency (3.9 g/cm2 h) compared to the foam-based membrane (2.5 g/cm2 h). Since the fog-water conversion efficiency decreased over time (to 0.5 g/cm2 h in 2 weeks) due to the absorbance of organic pollutants, a coating of titanium oxide was applied to the laser-treated side of the Janus membranes. As a result, the effective function of the systems became distinctly long-lasting and was well maintained for at least 60 days. Moreover, the fabricated systems were protected from further degradation by simply placing them under sunlight for several hours. Our results prove to be useful in developing asymmetric hydrophobic-superhydrophilic membranes, which have potential applications in high-precision drop control and in harvesting water from arid environments.

Development of ELISA-based diagnostic methods for the detection of haemorrhagic septicaemia in animals.

Haemorrhagic septicaemia (HS) is an acute infection of cattle and buffaloes caused by the B:2 serotype of Pasteurella multocida. This disease is highly endemic in South Asia. In some peracute cases, there is 100% mortality in infected animals within a few hours of infection. Therefore, timely diagnosis of infection may contribute to its treatment and control to minimize economic losses. The current work reported the development of ELISA-based assays for the detection of anti-P. multocida antibodies and pathogen i.e. P. multocida. Owing to high immunogenicity, membrane proteins (MPs) extracted from local isolates of P. multocida serotype B:2 (PM1, PM2, and PM3) were employed as a potential diagnostic antigen for the development of indirect ELISA (i-ELISA) to detect HS antibodies in animals. MPs extracted from PM1, PM2 and PM3 isolates showed very low heterogeneity; hence MPs from the PM3 isolate were selected for the development of i-ELISA. The concentration of MPs (as coating antigen) of 3.13 µg/well and test sera dilution 1:100 was found to be optimal to perform i-ELISA. The developed method was validated through the detection of anti-P. multocida antibodies in sera of mice, immunized with MPs and formalin killed cells from the three local isolates (PM1, PM2 and PM3) of P. multocida. The significantly higher antibody titer in immunized mice was determined compared to unimmunized mice with the cut off value of 0.139. To detect P. multocida directly from the blood of infected animals, whole cell-based ELISA (cb-ELISA) assay was developed. A better detection signal was observed in the assay where bacterial cells were directly adsorbed on plate wells as compared to poly L-lysine (PLL) assisted attachment at a cell concentration of 106 CFU and 107 CFU respectively. The developed assays can be scaled up and potentially be used for the rapid detection of HS antibodies to gauge the immune status of the animal as well as vaccination efficacy and pathogen detection.

Sustainability of phytoremediation: Post-harvest stratagems and economic opportunities for the produced metals contaminated biomass.

Heavy metals (HMs) are indestructible and non-biodegradable. Phytoremediation presents an opportunity to transfer HMs from environmental matrices into plants, making it easy to translocate from one place to another. The ornate features of HMs' phytoremediation are biophilia and carbon neutrality, compared to the physical and chemical remediation methods. Some recent studies related to LCA also support that phytoremediation is technically more sustainable than competing technologies. However, one major post-application challenge associated with HMs phytoremediation is properly managing HMs contaminated biomass generated. Such a yield presents the problem of reintroducing HMs into the environment due to natural decomposition and release of plant sap from the harvested biomass. The transportation of high yields can also make phytoremediation economically inviable. This review presents the design of a sustainable phytoremediation strategy using an ever-evolving life cycle assessment tool. This review also discusses possible post-phytoremediation biomass management strategies for the HMs contaminated biomass management. These strategies include composting, leachate compaction, gasification, pyrolysis, torrefaction, and metal recovery. Further, the commercial outlook for properly utilizing HMs contaminated biomass was presented.

First Detection of Extensively Drug-Resistant Salmonella Typhi Isolates Harboring VIM and GES Genes for Carbapenem Resistance from Faisalabad, Pakistan.

Rapid emergence of resistance in Salmonella enterica serovar Typhi (Salmonella Typhi) against most of the available therapeutic options for typhoid has rendered its treatment more difficult. This study sought to determine the current scenario of antimicrobial resistance in local isolates of Faisalabad following several treatment failure reports. Out of 300 clinical specimens collected in 2018, 45 isolates were identified as Salmonella Typhi. To assess changes, we compared their antibiogram profile with 31 Salmonella Typhi strains isolated in 2005. The isolates collected during 2018 showed a significant rise in antimicrobial drug resistance as compared with isolates revived from the cultures of 2005, including 15 multidrug-resistant (MDR), 20 extensively drug-resistant, and 14 pan drug-resistant isolates compared with only 8 MDRs from 2005. Notably, in 2018 isolates, resistance to azithromycin was seen in 75% of the isolates. Extended-spectrum beta-lactamase production was detected in 47% of Salmonella Typhi isolates and 18% isolates showed resistance against carbapenems. The sequences of two carbapenemase genes, VIM and GES, found in Salmonella Typhi were submitted in NCBI. The carbapenem resistance is rare in Enterobacteriaceae and probably first time reported in Salmonella Typhi. H58 haplotype was identified in the 2018 Salmonella Typhi isolates and PCR-restriction fragment length polymorphism method identified 16.7% of H58 strains that belonged to lineage I, 19.4% of H58 strains that belonged to lineage II, and the remaining 63.9% that belonged to the node. The regional difference in the antimicrobial resistance trend needs effective epidemiological studies.

High levels of blood glutamic acid and ornithine in children with intellectual disability.

Objectives: Aminoacidopathies are inborn errors of metabolism (IEMs) that cause intellectual disability in children. Luckily, aminoacidopathies are potentially treatable, if diagnosed earlier in life. The focus of this study was the screening of aminoacidopathies in a cohort of patients suspected for IEMs. Methods: Blood samples from healthy (IQ > 90; n = 391) and intellectually disabled (IQ < 70; n = 409) children (suspected for IEMs) were collected from different areas of Northern Punjab, Pakistan. An analytical HPLC assay was used for the screening of plasma amino acids. Results: All the samples (n = 800) were analyzed on HPLC and forty-three out of 409 patient samples showed abnormal amino acid profiles mainly in the levels of glutamic acid, ornithine and methionine. Plasma concentration (Mean ± SD ng/mL) were significantly high in 40 patients for glutamic acid (patients: 165 ± 38 vs. controls: 57 ± 8, p < 0.00001) and ornithine (patients: 3177 ± 937 vs. controls: 1361 ± 91, p < 0.0001). Moreover, 3 patients showed abnormally high (53.3 ± 8.6 ng/mL) plasma levels of methionine. Conclusion: In conclusion, biochemical analysis of samples from such patients at the metabolites level could reveal the underlying diseases which could be confirmed through advanced biochemical and genetic analyses. Thus, treatment to some of such patients could be offered. Thus burden of intellectual disability caused by such rare metabolic diseases could be reduced from the target populations.

Highly soluble and stable 'insertion domain' of the capsid penton base protein provides complete protection against infections caused by fowl adenoviruses.

In the current study, we have evaluated the protective efficacy of the 'insertion domain' which is commonly found in the capsid penton base protein of many adenoviruses. Using the 'insertion domain' of the penton base protein of a representative fowl adenovirus, fowl adenovirus serotype 4 (FAdV-4), we find that the 'insertion domain' can readily be expressed in a soluble form in the bacterial system, and can be purified in sufficient quantities through simple chromatographic methods. We demonstrate that the 'insertion domain', when employed as a subunit vaccine candidate, provides complete protection against hydropericardium syndrome, caused by FAdV-4, in chickens. The data presented here indicate that the protein, adjuvanted with Montanide™ ISA71 VG, provides complete protection in chickens against a lethal FAdV-4 challenge after administration of two doses (100 µg of the protein per dose) two weeks apart (the first dose at the 7th day of life and a booster dose at the age of 21 days). Furthermore, the purified protein can be stored at low temperatures without any observable loss in the protein integrity up to one year, tested so far. Due to the conserved nature of the 'insertion domain' across the penton base protein of fowl adenoviruses, it is suggested that homologous insertion domains could be employed as highly stable and cost-effective subunit vaccine candidates against infections caused by respective fowl adenoviruses.

Retraction Note: Screening and identification of bioactive compounds from citrus against non-structural protein 3 protease of hepatitis C virus genotype 3a by fluorescence resonance energy transfer assay and mass spectrometry.

[This retracts the article on p. 976 in vol. 12, PMID: 33312423.].

Enhancing Gas Solubility in Water via Femtosecond Laser-Induced Plasma.

The generation of laser-induced plasma at the gas-liquid interface provides many fundamental and interesting scientific phenomena such as ionization, sharp explosion, shock wave radiation, bubble creation, and water splitting. However, despite the extensive research in this area, there is no reference on the effect of the surrounding environment on the chemical processes that occur during the laser-induced plasma-water interaction. In this work, we investigate the effect of the surrounding gas environment on femtosecond laser-induced plasma when generated at the pure water-gas interface. Ultrashort laser pulses were applied to water in the presence of air and N2 and Ar gas environments. Formation of a significant number of nitrate-based species in water was observed after exposure to femtosecond laser-induced plasma in air and N2 environments. The detected NO3 ions formed in the laser-treated water led to the appearance of an absorption peak in the UV range, a significant decrease in the water pH value, and a significant increase in water's electrical conductivity. All induced properties of water were stable for 3 months of monitoring after laser treatment. Our work shows that the generation of laser-induced plasma in water propagating into a gaseous medium facilitates the interaction between the two media, as a result of which the compositions of substances present in the gaseous medium can be dissolved in water without increasing the gas pressure. The presented approach may find applications in areas such as water purification, material synthesis, and environmental stewardship.

In vitro evaluation of antiviral activity of Sisybrium irio (Khaksi) against SARS-COV-2.

SARS-CoV-2 pandemic, drawn attention to the need of virus culture. In vitro SARS-COV-2 culture was performed to carry out therapeutic, environmental and virus genome studies. Isolation of virus from nasopharyngeal swab was performed by inoculating virus positive samples in available cell lines. SARS-CoV-2 topography was observed by using Scanning Electron Microscopy (SEM). Virus specificity was defined by serological confirmation through neutralization assay with COVID 19 convalescent sera. The SARS-COV-2 virus replicated successfully in Vero cell lines (both in E6 and CCL-81). The TCID50 and PFUs of isolated virus were defined as 107 TCID50/mL and 1.4 Х 106 pfu/mL respectively. The virus particles with the SARS-CoV morphology was <150ɳM size. Virus inhibition in presence of convalescent sera of COVID-19 patients was observed. Sisybrium irio (Khaksi) was found cytotoxic on Vero E6 cell line and its antiviral activity could not be established against SARS-COV-2 virus in vitro. Successful isolated and archived native SARS-COV-2 may be utilized further for therapeutic, environmental and virus genome sequencing studies.

Dynamics of metal binding and mutation in yybP-ykoY riboswitch of Lactococcus lactis.

Riboswitch is a regulatory segment of messenger RNA (mRNA), which by binding to various cellular metabolites regulates the activity of mRNA via modulating transcription, translation, alternative splicing, and stability of the mRNA. yybP-ykoY riboswitch of Lactococcus lactis, which is present upstream of the yoaB gene, functions as a Mn2+-specific genetic ON-switch, and modulates expression of proteins which are significant for Mn2+ homeostasis. The P1.1 switch helix of the aptamer domain of the riboswitch contains an intrinsic transcription terminator structure, which gets stabilized with Mn2+ binding and causes disruption of terminator structure and allows the continuation of transcription. The current research work involved the evaluation of structural and dynamical properties of the yybP-ykoY riboswitch of L. lactis in its Mn2+-free, Mn2+-bound (wild-type), and Mn2+-bound mutant (A41U) states by applying molecular dynamics simulations. Based on the simulations, the effects of Mn2+ absence and A41U mutation were evaluated on the structure and dynamics of the riboswitches followed by the computation of the free energy of metal binding in the wild-type and the mutant riboswitches. The simulation results provided insights into the properties of the riboswitch with the focus on the dynamics of the P1.1 switch helix, and the manganese binding site designated as MB site, as well as the relative stability of the wild-type and the mutant riboswitches, which helped to understand the structural and dynamical role of the metal ion involved in the function of Mn2+-sensing riboswitch.