Multi-target weapons: diaryl-pyrazoline thiazolidinediones simultaneously targeting VEGFR-2 and HDAC cancer hallmarks

In anticancer drug discovery, multi-targeting compounds have been beneficial due to their advantages over single-targeting compounds. For instance, VEGFR-2 has a crucial role in angiogenesis and cancer management, whereas HDACs are well-known regulators of epigenetics and have been known to contribute significantly to angiogenesis and carcinogenesis. Herein, we have reported nineteen novel VEGFR-2 and HDAC dual-targeting analogs containing diaryl-pyrazoline thiazolidinediones and their in vitro and in vivo biological evaluation. In particular, the most promising compound 14c has emerged as a dual inhibitor of VEGFR-2 and HDAC. It demonstrated anti-angiogenic activity by inhibiting in vitro HUVEC proliferation, migration, and tube formation. Moreover, an in vivo CAM assay showed that 14c repressed new capillary formation in CAMs. In particular, 14c exhibited cytotoxicity potential on different cancer cell lines such as MCF-7, K562, A549, and HT-29. Additionally, 14c demonstrated significant potency and selectivity against HDAC4 in the sub-micromolar range. To materialize the hypothesis, we also performed molecular docking on the crystal structures of both VEGFR-2 (PDB ID: 1YWN) and HDAC4 (PDB-ID: 4CBY), which corroborated the designing and biological activity. The results indicated that compound 14c could be a potential lead to develop more optimized multi-target analogs with enhanced potency and selectivity.

Intermediate Cu-O-Si Phase in the Cu-SiO2/Si(111) System: Growth, Elemental, and Electrical Studies

We investigate here the strain-induced growth of Cu at 600 °C and its interactions with a thermally grown, 270 nm-thick SiO₂ layer on the Si(111) substrate. Our results show clear evidence of triangular voids and formation of triangular islands on the surface via a void-filling mechanism upon Cu deposition, even on a 270 nm-thick dielectric. Different coordination states, oxidation numbers, and chemical compositions of the Cu-grown film are estimated from the core level X-ray photoelectron spectroscopy (XPS) measurements. We find evidence of different compound phases including an intermediate mixed-state of Cu-O-Si at the interface. Emergence of a mixed Cu-O-Si intermediate state is attributed to the new chemical states of Cu ^x+, O ^x , and Si ^x+ observed in the high-resolution XPS spectra. This intermediate state, which is supposed to be highly catalytic, is found in the sample with a concentration as high as ∼41%. Within the Cu-O-Si phase, the atomic percentages of Cu, O, and Si are ∼1, ∼86, and ∼13%, respectively. The electrical measurements carried out on the sample reveal different resistive channels across the film and an overall n-type semiconducting nature with a sheet resistance of the order of 10⁶ Ω.

A high-frequency single nucleotide polymorphism in the MtrB sensor kinase in clinical strains of Mycobacterium tuberculosis alters its biochemical and physiological properties

The DNA polymorphisms found in clinical strains of Mycobacterium tuberculosis drive altered physiology, virulence, and pathogenesis in them. Although the lineages of these clinical strains can be traced back to common ancestor/s, there exists a plethora of difference between them, compared to those that have evolved in the laboratory. We identify a mutation present in ~80% of clinical strains, which maps in the HATPase domain of the sensor kinase MtrB and alters kinase and phosphatase activities, and affects its physiological role. The changes conferred by the mutation were probed by in-vitro biochemical assays which revealed changes in signaling properties of the sensor kinase. These changes also affect bacterial cell division rates, size and membrane properties. The study highlights the impact of DNA polymorphisms on the pathophysiology of clinical strains and provides insights into underlying mechanisms that drive signal transduction in pathogenic bacteria.

Single-crystal-to-single-crystal synthesis of a pseudostarch via topochemical azide-alkyne cycloaddition polymerization

There is high demand for polysaccharide-mimics as enzyme-stable substitutes for polysaccharides for various applications. Circumventing the problems associated with the solution-phase synthesis of such polymers, we report here the synthesis of a crystalline polysaccharide-mimic by topochemical polymerization. By crystal engineering, we designed a topochemically reactive crystal of a glucose-mimicking monomer decorated with azide and alkyne units. In the crystal, the monomers arrange in head-to-tail fashion with their azide and alkyne groups in a ready-to-react antiparallel geometry, suitable for their topochemical azide-alkyne cycloaddition (TAAC) reaction. On heating the crystals, these pre-organized monomer molecules undergo regiospecific TAAC polymerization, yielding 1,4-triazolyl-linked pseudopolysaccharide (pseudostarch) in a single-crystal-to-single-crystal manner. This crystalline pseudostarch shows better thermal stability than its amorphous form and many natural polysaccharides.

A Biocompatible, pH-Sensitive, and Magnetically Separable Superparamagnetic Hydrogel Nanocomposite as an Efficient Platform for the Removal of Cationic Dyes in Wastewater Treatment

A series of environment-friendly cationic dye adsorbents, namely, pH-sensitive superparamagnetic hydrogel nanocomposite AA-VSA-P/SPIONs systems with different concentrations of superparamagnetic iron oxide nanoparticles (SPIONs; 1.2, 3.2, and 5.2 wt %), was synthesized by free-radical polymerization reaction using two pH-sensitive monomers, acrylic acid (AA) and vinylsulfonic acid (VSA), in an optimum ratio, in the presence of presynthesized SPIONs. The structural properties, thermal stability, and chemical configuration of AA-VSA-P/SPIONs systems with different weight percentages of SPIONs were characterized by XRD, TGA, Raman spectroscopy, and FTIR spectroscopy. The systems show substantial efficiency as dye adsorbents for removing cationic dyes (MB dye) from aqueous solution in neutral to alkaline medium. Further, these systems exhibit easy magnetic separation capabilities from aqueous solutions after dye adsorption, even for a very low weight percentage of SPIONs. The adsorption kinetics, mechanism, and isotherms of these systems were evaluated. The study suggests consistency with the pseudo-second-order kinetic model, following an intraparticle diffusion mechanism, where the heterogeneous surface of the system having different activation energies for adsorption plays the crucial role in dye adsorption via chemisorption for higher pH medium, which was further substantiated by excellent data fit with the Freundlich isotherm model. Biocompatibility and regeneration-ability studies establish the environment-friendliness and cost effectivity of the system.

Optical-Property-Enhancing Novel Near-Infrared Active Niosome Nanoformulation for Deep-Tissue Bioimaging

Indocyanine green (ICG) is a clinically approved near-infrared (NIR) contrast agent used in medical diagnosis. However, ICG has not been used to its fullest for biomedical imaging applications due to its low fluorescence quantum yield, aqueous instability, concentration-dependent aggregation, and photo and thermal degradations, leading to quenching of its fluorescence emission. In the present study, a nanosized niosomal formulation, ICGNiosomes (ICGNios), is fabricated to encapsulate and protect ICG from degradation. Interestingly, compared to free ICG, the ICGNios exhibited higher fluorescence quantum yield and fluorescence emission with a bathochromic shift. Also, ICGNios nanoparticles are biocompatible, biodegradable, and readily uptaken by the cells. Furthermore, ICGNios show more enhanced fluorescence intensity through ∼1 cm thick chicken breast tissue compared to free ICG, which showed minimal emission through the same thickness of tissue. Our results suggest that ICGNios could offer a promising platform for deep-tissue NIR in vivo imaging to visualize inaccessible tissue microstructures for disease diagnosis and therapeutics.

Gemini Lipopeptide Bearing an Ultrashort Peptide for Enhanced Transfection Efficiency and Cancer-Cell-Specific Cytotoxicity

Cationic gemini lipopeptides are a relatively new class of amphiphilic compounds to be used for gene delivery. Through the possibility of incorporating short peptides with cell-penetrating functionalities, these lipopeptides may be advantageous over traditional cationic lipids. Herein, we report the design, synthesis, and application of a novel cationic gemini lipopeptide for gene delivery. An ultrashort peptide, containing four amino acids, arginine-cysteine-cysteine-arginine, serves as a cationic head group, and two α-tocopherol moieties act as hydrophobic anchoring groups. The new lipopeptide (ATTA) is incorporated into the conventional liposomes, containing 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) and 1,2-dioleoyl-sn-glycerol-3-phosphoethanolamine (DOPE), at different molar ratios. The formulated liposomes are characterized and screened for better transfection efficiency. Transfection activity in multiple human cell lines from cancerous and noncancerous origins indicates that the inclusion of an optimal ratio of ATTA in the liposomes substantially enhances the transfection efficiency, superior to that of a traditional liposome, DOTAP-DOPE. Cytotoxicity of ATTA-containing formulations against multiple cell lines indicates potentially distinct activity between cancer and noncancer cell lines. Furthermore, lipoplexes of the ATTA-containing formulations with anticancer therapeutic gene, plasmid encoding tumor necrosis factor-related apoptosis-inducing ligand (pTRAIL), induce obviously more cytotoxicity than conventional formulations. The results indicate that arginine-rich cationic lipopeptide appears to be a promising ingredient in gene delivery vector formulations to enhance transfection efficiency and cell-selective cytotoxicity.

Study of the Variation of the Electronic Distribution and Motional Dynamics of Two Independent Molecules of an Asymmetric Unit of Atorvastatin Calcium by Solid-State NMR Measurements

Significant changes in the spin-lattice time and chemical shift anisotropy (CSA) parameters are observed in two independent molecules of an asymmetric unit of atorvastatin calcium (ATC-I) (which is referred to as "a"- and "b"-type molecules by following Wang et al.). The longitudinal magnetization decay curve is fitted by two exponentials-one with longer relaxation time and another with shorter relaxation time for most of the carbon nuclei sites. The local correlation time also varies significantly. This is the experimental evidence of the coexistence of two different kinds of motional degrees of freedom within ATC-I molecule. The solubility and bioavailability of the drug molecule are enhanced due to the existence of two different kinds of dynamics. Hence, the macroscopic properties like solubility and bioavailability of a drug molecule are highly correlated with its microscopic properties. The motional degrees of freedom of "a"- and "b"-type molecules are also varied remarkably at certain carbon nuclei sites. This is the first time the change in the molecular dynamics of two independent molecules of an asymmetric unit of atorvastatin calcium is quantified using solid-state NMR methodology. These types of studies, in which the chemical shift anisotropy (CSA) parameters and spin-lattice relaxation time provide information about the change in electronic distribution and the spin dynamics at the various crystallographic location of the drug molecule, will enrich the field "NMR crystallography". It will also help us to understand the electronic distribution around a nucleus and the nuclear spin dynamics at various parts of the molecule, which is essential to develop the strategies for the administration of the drug.

Interaction of Human C5a with the Major Peptide Fragments of C5aR1: Direct Evidence in Support of "Two-Site" Binding Paradigm

The C5a receptor's (C5aR1) physiological function in various tissues depends on its high-affinity binding to the cationic proinflammatory glycoprotein C5a, produced during the activation of the complement system. However, an overstimulated complement can quickly alter the C5a-C5aR1 function from physiological to pathological, as has been noted in the case of several chronic inflammation-induced diseases like asthma, lung injury, multiorgan failure, sepsis, and now COVID-19. In the absence of the structural data, the current study provides the confirmatory biophysical validation of the hypothesized "two-site" binding interactions of C5a, involving (i) the N-terminus (NT) peptide ("Site1") and (ii) the extracellular loop 2 (ECL2) peptide of the extracellular surface (ECS) of the C5aR1 ("Site2"), as illustrated earlier in the reported model structural complex of C5a-C5aR1. The biophysical and computational data elaborated in the study provides an improved understanding of the C5a-C5aR1 interaction at an atomistic resolution, highlighting the energetic importance of the aspartic acids on the NT-peptide of C5aR1 toward binding of C5a. The current study can potentially advance the search and optimization of new-generation alternative "antibodies" as well as "neutraligands" targeting the C5a to modulate its interaction with C5aR1.

New concepts of inverse fuzzy mixed graphs and its application

Fuzzy mixed graph (FMG) can be used to model some graphical intercommunication network systems if there are many directed and undirected relations between some vertices. In inverse fuzzy graph, the membership value of edges are greater than or equal to the minimum of the membership value of the corresponding vertices. In inverse fuzzy mixed graph (IFMG), directed and undirected relations exist between some vertices and it can be used to analyze many graphical problems of real life such that the membership values of edges are greater than or equal to the minimum of the membership value of the corresponding pair of vertices. In this article, the concept of IFMG is introduced first with some of its properties. Then some isomorphic properties are studied and complement of IFMG is given. Different types of operations like union, intersection, product and join between two IFMGs are defined and investigated some of their related results. An algorithm of the proposed method is executed to identify some vertices. An application is depicted using the concept IFMG to examine the order of vertices in a social network group according to communication gaps.

TRIMs: selective recruitment at different steps of the NF-κB pathway-determinant of activation or resolution of inflammation

TNF-α-induced NF-κB pathway is an essential component of innate and adaptive immune pathway, and it is tightly regulated by various post-translational modifications including ubiquitination. Oscillations in NF-κB activation and temporal gene expression are emerging as critical determinants of inflammatory response, however, the regulators of unique outcomes in different patho-physiological conditions are not well understood. Tripartite Motif-containing proteins (TRIMs) are RING domain-containing E3 ligases involved in the regulation of cellular homeostasis, metabolism, cell death, inflammation, and host defence. Emerging reports suggest that TRIMs are recruited at different steps of TNF-α-induced NF-κB pathway and modulate via their E3 ligase activity. TRIMs show synergy and antagonism in the regulation of the NF-κB pathway and also regulate it in a feedback manner. TRIMs also regulate pattern recognition receptors (PRRs) mediated inflammatory pathways and may have evolved to directly regulate a specific arm of immune signalling. The review emphasizes TRIM-mediated ubiquitination and modulation of TNF-α-regulated temporal and NF-κB signaling and its possible impact on unique transcriptional and functional outcomes.

Short-Range Structural Insight into Lithium-Substituted Barium Vanadate Glasses Using Raman and EPR Spectroscopy as Probes

We present a corroborative study of the structural characterization of lithium-substituted barium vanadate glasses using Raman and electron paramagnetic resonance (EPR) spectroscopy. Investigation of the thermal and physical properties of these glasses showed a gradual increase in the concentration of nonbridging oxygen. Raman and EPR analysis gave an insight into the changing structure of the glasses. Both the spectroscopic techniques confirmed that vanadium is present in the glasses as distorted VO₆ octahedra. From the analysis of both spectroscopic techniques, it is proposed that the lithium ion prefers to occupy planar positions of the VO₆ octahedra, thus reducing the tetragonal distortion and making the environment around the network-forming unit in the glass matrix more homogeneous as we increase the lithium content. The concentration of V⁴⁺ showed a non-monotonic variation with an increase in Li₂O as indicated by Raman studies and confirmed by EPR, which indicates a structural change in the distorted VO₆ octahedra.

Association of IRS1 (Gly972Arg) and IRS2 (Gly1057Asp) genes polymorphisms with OSA and NAFLD in Asian Indians

AIM AND OBJECTIVE

The aim of the study was to investigate the relationships between insulin receptor substrate (IRS) 1 (Gly972Arg) and IRS2 (Gly1057Asp) genes with obstructive sleep apnea (OSA) and non-alcoholic fatty liver disease (NAFLD) in Asian Indians.

METHOD

A total of 410 overweight/obese subjects (130 with OSA with NAFLD, 100 with OSA without NAFLD, 95 without OSA and with NAFLD and 85 without OSA and without NAFLD) were recruited. Degree of NAFLD was based on liver ultrasound and of OSA on overnight polysomnography. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism and confirmed by gene sequencing.

RESULT

Mean values of blood pressure, body fat markers, blood glucose, lipids, liver function, and markers of insulin resistance were significantly increased in OSA and NAFLD subjects (p<0.05). In addition, according to age (years) categories, blood pressure, blood glucose, lipids, obesity markers, and markers of insulin resistance were significantly higher in 45-60 years group as compared to 20-45 years group (p<0.05). In IRS1 gene, the genotype frequency (%) of Arg/Arg was significantly higher in NAFLD and OSA subjects. In addition, Gly/Arg genotype of IRS1 gene was associated with significantly higher body mass index, fat mass, %body fat, triglycerides, cholesterol, alkaline phosphate, aspartate transaminase, fasting insulin and HOMA-IR levels in OSA and NAFLD subjects. No significant difference in genotype frequencies of IRS2 was observed between four groups. Further we found that subjects carrying IRS1 Gly/Arg (OR 4.49, 95% C.I. 1.06-12.52, p = 0.002) genotype possess a much higher risk of OSA and NAFLD compared to IRS2 Gly/Asp (OR 1.01, 95% C.I. 0.8-2.56, p = 0.05). In sub group analysis of IRS1 Gly/Arg have significant differences between the mild, moderate and severe group (P<0.05). In addition, patients with the 'Gly' allele were inclined to develop more severe OSA.

CONCLUSION

We concluded that Asian Indian subject carrying the allele Gly972Arg polymorphism of IRS1 is predisposed to develop OSA and NAFLD.

Thermoelectric Properties of Pristine Graphyne and the BN-Doped Graphyne Family

In this paper, we have investigated the thermoelectric properties of BN-doped graphynes and compared them with respect to their pristine counterpart using first-principles calculations. The effect of temperature on the thermoelectric properties has also been explored. Pristine γ-graphyne is an intrinsic band gap semiconductor and the band gap significantly increases due to the incorporation of boron and nitrogen atoms into the system, which simultaneously results in high electrical conductivity, a large Seebeck coefficient, and low thermal conductivity. The Seebeck coefficient for all these systems is significantly higher than that of conventional thermoelectric materials, suggesting their potential in thermoelectric applications. Among all the considered systems, the "graphyne-like BN sheet" has the highest electrical conductance and lowest thermal conductance, ensuring its superiority in thermoelectric properties over the other studied systems. We find that a maximum full ZT of ∼6 at room temperature is accessible in the "graphyne-like BN sheet".

Enrichment of Crystal Field Modification via Incorporation of Alkali K+ Ions in YVO4:Ho3+/Yb3+ Nanophosphor and Its Hybrid with Superparamagnetic Iron Oxide Nanoparticles for Optical, Advanced Anticounterfeiting, Uranyl Detection, and Hyperthermia Applications

In this work, we report a polyol route for easy synthesis of upconversion (UC) phosphor nanoparticles, YVO₄:Ho³⁺-Yb³⁺-K⁺, which enables large-scale production and enhancement of luminescence. Upon 980 nm laser excitation, the UC emission spectrum shows a sharp bright peak at ∼650 nm of Ho³⁺ ion; and the luminescence intensity increases twofold upon K⁺ codoping. Upon 300 nm excitation, the downconversion emission spectrum shows a broad peak in the 400-500 nm range (related to the charge transfer band of V-O) along with Ho³⁺ peaks. In addition, the polyethylene glycol-coated UC nanoparticles are highly water-dispersible and their hybrid with Fe₃O₄ nanoparticles shows magnetic-luminescence properties. A hyperthermia temperature is achieved from this hybrid. Both UC and hybrid nanoparticles show interesting security ink properties upon excitation by a 980 nm laser. The particles are invisible in normal light but visible upon 980 nm excitation and are useful in display devices, advanced anticounterfeiting purposes, and therapy of cancer via hyperthermia and bioimaging (since it shows red emission at ∼650 nm). Using UC nanoparticles, detection of uranyl down to 20 ppm has been achieved.

Brilliant Nonlinear Optical Response of Ho3+ and Yb3+ Activated YVO4 Nanophosphor and Its Conjugation with Fe3O4 for Smart Anticounterfeit and Hyperthermia Applications

YVO4:Ho3+/Yb3+ nanophosphors prepared by an effective polyol-mediated route show dual-mode behavior in photoluminescence. Upon 980 nm excitation, the upconversion red emission spectrum exhibits a bright red peak at ∼650 nm, characteristic of the electronic transition of the Ho3+ ion via involvement of two-photon absorption, which has been confirmed by the power-dependent luminescence study. Moreover, at 300 nm excitation, downconversion emission peaks are observed at 550, 650, and ∼755 nm. The nonradiative resonant energy transfer occurs from the V-O charge transfer band to Ho3+ ions, resulting in an improved emission of Ho3+ ions. Moreover, polyethylene glycol-coated nanoparticles make it suitable for water dispersibility; and these particles are conjugated with Fe3O4 nanoparticles to form magnetic-luminescent hybrid nanoparticles. Highly water-dispersible magnetic-luminescent hybrid material attained the hyperthermia temperature (∼42 °C) under an applied AC magnetic field. The specific absorption rate value is found to be high (138 W/g), which is more than that of pure superparamagnetic Fe3O4 nanoparticles. At 300 nm excitation, the high quantum yield value of ∼27% is obtained from YVO4:Ho3+/Yb3+, which suggests that it is a good phosphor material. By employing the neutron activation analysis technique, it is shown that nanophosphor particles can absorb Au3+ up to the ppm level. Interestingly, such nanophosphor also shows the potentiality for anticounterfeiting applications.

Association of eNOS and MCP-1 Genetic Variants with Type 2 Diabetes and Diabetic Nephropathy Susceptibility: A Case-Control and Meta-Analysis Study

Type 2 diabetes (T2D) and its secondary complications result from the complex interplay of genetic and environmental factors. To understand the role of these factors on disease susceptibility, the present study was conducted to assess the association of eNOS and MCP-1 variants with T2D and diabetic nephropathy (DN) in two ethnically and geographically different cohorts from North India. A total of 1313 subjects from two cohorts were genotyped for eNOS (rs2070744, rs869109213 and rs1799983) and MCP-1 (rs1024611 and rs3917887) variants. Cohort-I (Punjab) comprised 461 T2D cases (204 T2D with DN and 257 T2D without DN) and 315 healthy controls. Cohort-II (Jammu and Kashmir) included 337 T2D (150 T2D with DN and 187 T2D without DN) and 200 controls. Allele, genotype and haplotype frequencies were compared among the studied participants, and phenotype-genotype interactions were determined. Meta-analysis was performed to investigate the association between the selected variants and disease susceptibility. All three eNOS variants were associated with 1.5-4.0-fold risk of DN in both cohorts. MCP-1 rs1024611 conferred twofold risk towards DN progression in cohort-II, while rs3917887 provided twofold risk for both T2D and DN in both cohorts. eNOS and MCP-1 haplotypes conferred risk for T2D and DN susceptibility. Phenotype-genotype interactions showed significant associations between the studied variants and anthropometric and biochemical parameters. In meta-analysis, all eNOS variants conferred risk towards DN progression, whereas no significant association was observed for MCP-1 rs1024611. We show evidences for an association of eNOS and MCP-1 variants with T2D and DN susceptibility.

Rabeprazole has efficacy per se and reduces resistance to temozolomide in glioma via EMT inhibition

PURPOSE

Epithelial to mesenchymal transition (EMT) is pivotal in embryonic development and wound healing, whereas in cancer it inflicts malignancy and drug resistance. The recognition of an EMT-like process in glioma is relatively new and its clinical and therapeutic significance has, as yet, not been fully elucidated. Here, we aimed to delineate the clinical significance of the EMT-like process in glioma and its therapeutic relevance to rabeprazole.

METHODS

We investigated the expression profiles of EMT-associated proteins in primary glioma biopsies through Western blotting and immunohistochemistry, and correlated them with various clinicopathological features and data listed in the cancer genome atlas (TCGA). In addition, the anticancer efficacy of rabeprazole and its therapeutic relevance to EMT along with temozolomide chemo-sensitization were assessed using multiple cell-based assays, Western blotting and confocal imaging. For in vivo assessment, we used a stereotaxic C6-rat glioma model.

RESULTS

Expression analysis of EMT-associated proteins in glioma biopsies, in conjunction with clinicopathological and TCGA dataset analyses, revealed non-canonical expression of E/N-cadherin and upregulation of GFAP, vimentin and β-catenin. The increased expression of EMT-associated proteins may attribute to glioma malignancy and a poor patient prognosis. Subsequent in vitro studies revealed that rabeprazole treatment attenuated glioma cell growth and migration, and induced apoptosis. Rabeprazole suppressed EMT by impeding AKT/GSK3β phosphorylation and/or NF-κB signaling and sensitized temozolomide resistance. Additional in vivo studies showed restricted tumor growth and inhibited expression of EMT-associated proteins after rabeprazole treatment.

CONCLUSIONS

Our data revealed (i) a clinical association of the EMT-like process with glioma malignancy and a poor survival and (ii) an anticancer and temozolomide sensitizing effect of rabeprazole by repressing EMT.

Enzymatic approaches in the bioprocessing of shellfish wastes

Several tonnes of shellfish wastes are generated globally due to the mass consumption of shellfish meat from crustaceans like prawn, shrimp, lobster, crab, Antarctic krill, etc. These shellfish wastes are a reservoir of valuable by-products like chitin, protein, calcium carbonate, and pigments. In the present scenario, these wastes are treated chemically to recover chitin by the chitin and chitosan industries, using hazardous chemicals like HCl and NaOH. Although this process is efficient in removing proteins and minerals, the unscientific dumping of harmful effluents is hazardous to the ecosystem. Stringent environmental laws and regulations on waste disposal have encouraged researchers to look for alternate strategies to produce near-zero wastes on shellfish degradation. The role of enzymes in degrading shellfish wastes is advantageous yet has not been explored much, although it produces bioactive rich protein hydrolysates with good quality chitin. The main objective of the review is to discuss the potential of various enzymes involved in shellfish degradation and their opportunities and challenges over chemical processes in chitin recovery.

State of the Art and Prospects for Halide Perovskite Nanocrystals

Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of perovskite nanocrystals and understanding of their properties and applications. In this comprehensive review, researchers having expertise in different fields (chemistry, physics, and device engineering) of metal-halide perovskite nanocrystals have joined together to provide a state of the art overview and future prospects of metal-halide perovskite nanocrystal research.

Aflatoxin B1 Induced Structural and Conformational Changes in Bovine Serum Albumin: A Multispectroscopic and Circular Dichroism-Based Study

Aflatoxin B₁ (AFB₁) is a mutagen that has been categorized as a group 1 human carcinogen by the International Agency for Research on Cancer. It is produced as a secondary metabolite by soil fungi Aspergillus flavus and Aspergillus parasiticus . Here, in this study, the effect of AFB₁ on the structure and conformation of bovine serum albumin (BSA) using multispectroscopic tools like fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy, and circular dichroism spectropolarimetry has been ascertained. Ultraviolet absorption spectroscopy revealed hyperchromicity in the absorption spectra of BSA in the presence of AFB₁. The binding constant was calculated in the range of 10⁴ M^-1, by fluorescence spectroscopy suggesting moderate binding of the toxin to BSA. The study also confirms the static nature of fluorescence quenching. The stoichiometry of binding sites was found to be unity. The competing capability of warfarin for AFB₁ was higher than ibuprofen as calculated from site marker displacement assay. Förster resonance energy transfer confirmed the high efficiency of energy transfer from BSA to AFB₁. Circular dichroism spectropolarimetry showed a decrease in the α-helix in BSA in the presence of AFB₁. The melting temperature of BSA underwent an increment in the presence of a mycotoxin from 62.5 to 70.3 °C. Molecular docking confirmed the binding of AFB₁ to subdomain IIA in BSA.

Mycobacterium tuberculosis Cell Wall Permeability Model Generation Using Chemoinformatics and Machine Learning Approaches

The drug-resistant strains of Mycobacterium tuberculosis (M.tb) are evolving at an alarming rate, and this indicates the urgent need for the development of novel antitubercular drugs. However, genetic mutations, complex cell wall system of M.tb, and influx-efflux transporter systems are the major permeability barriers that significantly affect the M.tb drugs activity. Thus, most of the small molecules are ineffective to arrest the M.tb cell growth, even though they are effective at the cellular level. To address the permeability issue, different machine learning models that effectively distinguish permeable and impermeable compounds were developed. The enzyme-based (IC₅₀) and cell-based (minimal inhibitory concentration) data were considered for the classification of M.tb permeable and impermeable compounds. It was assumed that the compounds that have high activity in both enzyme-based and cell-based assays possess the required M.tb cell wall permeability. The XGBoost model was outperformed when compared to the other models generated from different algorithms such as random forest, support vector machine, and naïve Bayes. The XGBoost model was further validated using the validation data set (21 permeable and 19 impermeable compounds). The obtained machine learning models suggested that various descriptors such as molecular weight, atom type, electrotopological state, hydrogen bond donor/acceptor counts, and extended topochemical atoms of molecules are the major determining factors for both M.tb cell permeability and inhibitory activity. Furthermore, potential antimycobacterial drugs were identified using computational drug repurposing. All the approved drugs from DrugBank were collected and screened using the developed permeability model. The screened compounds were given as input in the PASS server for the identification of possible antimycobacterial compounds. The drugs that were retained after two filters were docked to the active site of 10 different potential antimycobacterial drug targets. The results obtained from this study may improve the understanding of M.tb permeability and activity that may aid in the development of novel antimycobacterial drugs.

Detection of the Chilli Leaf Curl Virus Using an Attenuated Total Reflection-Mediated Localized Surface-Plasmon-Resonance-Based Optical Platform

The development of a nanoparticle-based optical platform has been presented as a biosensor for detecting target-specific plant virus DNA. The binding dynamics of gold nanoparticles has been studied on the amine-functionalized surface by the attenuated total reflection (ATR)-based evanescent wave absorption method monitoring the localized surface plasmon resonance (LSPR). The developed surface was established as a refractive index sensor by monitoring the LSPR absorption peak of gold nanoparticles. This nanoparticle-immobilized surface was explored to establish as a biosensing platform with target-specific immunoglobulin (IgG) antibody-antigen interaction. The IgG concentration-dependent variation of absorbance was correlated with the refractive index change. After successfully establishing this ATR configuration as an LSPR-based biosensor, the single-stranded DNA of the chilli leaf curl virus was detected using its complementary DNA sequence as a receptor. The limit of detection of this sensor was determined to be 1.0 μg/mL for this target viral DNA. This ATR absorption technique has enormous potential as an LSPR based nano-biosensor for the detection of other begomoviruses.

Modelling the Service Experience Encounters Using User-Generated Content: A Text Mining Approach

Among services, the immense growth of Indian tourism in the last years has attracted the interest of practitioners, researchers, and governments. Service experiences at the point of encounter can impact the consumption of these tourism services extensively. However, measuring the service experience at the point of service encounter becomes a bit difficult. The tourists who visit India often share their experiences immediately regarding their service encounter in social media. These tweets often have high sentiments and emotional content. In this study, we attempt to identify factors which impact customer service experience, at the point of service encounter, by mining social media discussions. After removing spurious tweets, 7,91,804 tweets were identified and analysed in this study. Factors such as accessibility, accommodation, assurance, cultural attraction, Jugaadu service flexibility, cleanliness, hospitality, price, restaurant, and security were identified using topic modelling, topic association mining, and sentiment analysis. We attempt to model these experiences and their drivers across five zones of India, namely North, South, East, West, and North-East India. Our inferential analysis highlights that the importance and impact of these factors differ significantly zone wise across India, which indicates high location specificity of factors which impact the customer service experience. The study elaborates implications for theory and practice based on our findings.

Aggregation-Induced Emission-Based Material for Selective and Sensitive Recognition of Cyanide Anions in Solution and Biological Assays

Cyanide is one of the highly poisonous pollutants to our environment and toxic to human health. It is important to develop the widely applicable methods for their recognition to secure safe uses for people coming into contact and handling cyanide and their derivatives. In this regard, the aggregation-induced emission materials possess high potential for the development of simple, fast, and convenient methods for cyanide detection through either "turn-off" or "turn-on". Among the AIE-based materials, tetraphenylethylene is a promising sensor for various sensing applications. In this paper, we have designed and synthesized a TPE-based chemosensor, which shows high sensitivity and displays good selectivity for cyanide (CN-) over others in the presence of interfering Cl-, I-, F-, Br-, HSO4 -, H2PO4 -, NO3 -, HCO3 -, and ClO4 - anions employed. The naked-eye, UV-vis, and fluorescence methods are employed to evaluate the performance of probe 1 toward CN- detection. From these experiments, CN- ions can be detected with a limit of detection as low as 67 nM, which is comparatively lower than that of the World Health Organization (WHO) permissible limit of the cyanide anion, that is, 1.9 μM. From the Job's plot, the 1:1 stoichiometric complexation reaction between probe 1 and CN- was found. The probe was efficiently applied for the detection of CN- ions using a paper strip method. The probe 1 also showed the potential of detecting CN- ions in various food items and in the cell line.

Strategies to target SARS-CoV-2 entry and infection using dual mechanisms of inhibition by acidification inhibitors

Many viruses utilize the host endo-lysosomal network for infection. Tracing the endocytic itinerary of SARS-CoV-2 can provide insights into viral trafficking and aid in designing new therapeutic strategies. Here, we demonstrate that the receptor binding domain (RBD) of SARS-CoV-2 spike protein is internalized via the pH-dependent CLIC/GEEC (CG) endocytic pathway in human gastric-adenocarcinoma (AGS) cells expressing undetectable levels of ACE2. Ectopic expression of ACE2 (AGS-ACE2) results in RBD traffic via both CG and clathrin-mediated endocytosis. Endosomal acidification inhibitors like BafilomycinA1 and NH4Cl, which inhibit the CG pathway, reduce the uptake of RBD and impede Spike-pseudoviral infection in both AGS and AGS-ACE2 cells. The inhibition by BafilomycinA1 was found to be distinct from Chloroquine which neither affects RBD uptake nor alters endosomal pH, yet attenuates Spike-pseudovirus entry. By screening a subset of FDA-approved inhibitors for functionality similar to BafilomycinA1, we identified Niclosamide as a SARS-CoV-2 entry inhibitor. Further validation using a clinical isolate of SARS-CoV-2 in AGS-ACE2 and Vero cells confirmed its antiviral effect. We propose that Niclosamide, and other drugs which neutralize endosomal pH as well as inhibit the endocytic uptake, could provide broader applicability in subverting infection of viruses entering host cells via a pH-dependent endocytic pathway.

Interpretations on the Interaction between Protein Tyrosine Phosphatase and E7 Oncoproteins of High and Low-Risk HPV: A Computational Perception

The most prevalent and common sexually transmitted infection is caused by human papillomavirus (HPV) among sexually active women. Numerous genotypes of HPV are available, among which the major oncoproteins E6 and E7 lead to the progression of cervical cancer. The E7 oncoprotein interacts with cytoplasmic tumor suppressor protein PTPN14, which is the key regulator of cellular growth control pathways effecting the reduction of steady-state level. Disrupting the interaction between the tumor suppressor and the oncoprotein is vital to cease the development of cancer. Hence, the mechanism of interaction between E7 and tumor suppressor is explored through protein-protein and protein-ligand binding along with the conformational stability studies. The obtained results state that the LXCXE domain of HPV E7 of high and low risks binds with the tumor suppressor protein. Also, the small molecules bind in the interface of E7-PTPN14 that disrupts the interaction between the tumor suppressor and oncoprotein. These results were further supported by the dynamics simulation stating the stability over the bounded complex and the energy maintained during postdocking as well as postdynamics calculations. These observations possess an avenue in the drug discovery that leads to further validation and also proposes a potent drug candidate to treat cervical cancer caused by HPV.

Grape Seed Extract Assisted Synthesis of Dual-Functional Anatase TiO2 Decorated Reduced Graphene Oxide Composite for Supercapacitor Electrode Material and Visible Light Photocatalytic Degradation of Bromophenol Blue Dye

The grape extract is a potential natural reducing agent because of its high phenolic content. The extracts of seeds, skin, and pulp of grape were prepared by digestion, grinding, and soxhlet methods and used for reducing graphene oxide (GO). The reduced GO made using the soxhlet extract of grape seed (GRGO) was hydrothermally treated with titanium dioxide (TiO₂) for the synthesis of GRGO-TiO₂ nanocomposite. The X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), UV-vis, photoluminescence, and Raman spectra studies further confirmed the formation of GRGO and the GRGO-TiO₂ hybrid. Scanning electron microscope and transmission electron microscope studies showed the decoration of spherical TiO₂ particles (<100 nm) on the few-layered GRGO sheets. The GRGO-TiO₂ hybrid was explored as a working electrode for supercapacitors and visible light photocatalyst for water decontamination. GRGO-TiO₂ showed higher specific capacitance (175 F g^-1) than GRGO (150 F g^-1) and TiO₂ (125 F g^-1) in an aqueous electrolyte. GRGO-TiO₂ exhibited 83.6% capacitance retention even after 2000 cycles, indicating the good stability of the material. Further, under visible light irradiation (λ > 400 nm), GRGO-TiO₂ showed ∼30% higher photo-oxidation of the bromophenol blue (BPB) dye than TiO₂. Also, GRGO-TiO₂ decreased the total organic carbon content of BPB from 92 to 18 ppm. Overall, the soxhlet extract of grape seed was found to be a cost-effective reducing agent for the preparation of GRGO, which is a suitable material to be used in supercapacitors and photocatalysis.

Effect of Concomitant Hydroxyurea Therapy with Rutin and Gallic Acid: Integration of Pharmacokinetic and Pharmacodynamic Approaches

Hydroxyurea (HU) is the first-ever approved drug by USFDA for sickle cell anemia (SCA). However, its treatment is associated with severe side effects like myelosuppression. Current studies are focused on the supplementation therapy for symptomatic management of SCA. In the present study, we aimed to explore rutin's and gallic acid's potential individually, for concomitant therapy with HU using pharmacokinetic and pharmacodynamic approaches since there is no such precedent till date. In vivo pharmacokinetic studies of HU in rats showed that rutin could be safely co-administered with HU, while gallic acid significantly raised the plasma concentration of HU. Both the phytochemicals did not have any marked inhibitory effect on urease but have considerable effects on horseradish peroxidase enzyme. The experimental phytoconstituents displayed a very low propensity to cause in vitro hemolysis. Gallic acid markedly enhanced the HU-induced decrease in lymphocyte proliferation. A substantial improvement by rutin or gallic acid was observed in HU-induced reduction of the main hematological parameters in rats. Combined treatment of HU with rutin and gallic acid reduced serum levels of both IL-6 and IL-17A. Overall, both rutin and gallic acid are found to have promising phytotherapy potential with HU. Further exploration needs to be done on both candidates for use as phytotherapeutics for SCA.

Trace-Level Humidity Sensing from Commercial Organic Solvents and Food Products by an AIE/ESIPT-Triggered Piezochromic Luminogen and ppb-Level "OFF-ON-OFF" Sensing of Cu2+: A Combined Experimental and Theoretical Outcome

Selective and sensitive moisture sensors have attracted immense attention due to their ability to monitor the humidity content in industrial solvents, food products, etc., for regulating industrial safety management. Herein, a hydroxy naphthaldehyde-based piezochromic luminogen, namely, 1-{[(2-hydroxyphenyl)imino]methyl}naphthalen-2-ol (NAP-1), has been synthesized and its photophysical and molecular sensing properties have been investigated by means of various spectroscopic tools. Owing to the synergistic effect of both aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) along with the restriction of C=N isomerization, the probe shows bright yellowish-green-colored keto emission with high quantum yield after the interaction with a trace amount of water. This makes NAP-1 a potential sensor for monitoring water content in the industrial solvents with very low detection limits of 0.033, 0.032, 0.034, and 0.033% (v/v) from tetrahydrofuran (THF), acetone, dimethyl sulfoxide (DMSO), and methanol, respectively. The probe could be used in the food industry to detect trace moisture in the raw food samples. The reversible switching behavior of NAP-1 makes it suitable for designing an INHIBIT logic gate with an additional application in inkless writing. In addition, an Internet of Things-(IoT) based prototype device has been proposed for on-site monitoring of the moisture content by a smartphone via Bluetooth or Wi-Fi. The aggregated probe also has the ability to recognize Cu²⁺ from a purely aqueous medium via the chelation-enhanced quenching (CHEQ) mechanism, leading to ∼84% fluorescence quenching with a Stern-Volmer quenching constant of 1.46 × 10⁴ M^-1 and with an appreciably low detection threshold of 57.2 ppb, far below than recommended by the World Health Organization (WHO) and the United States Environmental Protection Agency (U.S. EPA). The spectroscopic and theoretical calculations (density functional theory (DFT), time-dependent DFT (TD-DFT), and natural bond orbital (NBO) analysis) further empower the understanding of the mechanistic course of the interaction of the host-guest recognition event.

Chemical Space Exploration of DprE1 Inhibitors Using Chemoinformatics and Artificial Intelligence

Tuberculosis (TB), entrained by Mycobacterium tuberculosis, continues to be an enfeebling disease, killing nearly 1.5 million people in 2019, with 2 billion people worldwide affected by latent TB. The multidrug-resistant and totally drug-resistant emerging strains further exacerbate the TB infection. The cell wall of bacteria provides critical virulence components such as cell surface proteins, regulators, signal transduction proteins, and toxins. The cell wall biosynthesis pathway of Mycobacterium tuberculosis is exhaustively studied to discover novel drug targets. Decaprenylphosphoryl-β-d-ribose-2'-epimerase (DprE1) is an important enzyme involved in the arabinogalactan biosynthetic pathway of Mycobacterium tuberculosis cell wall and is essential for both latent and persistent bacterial infection. We analyzed all known ∼1300 DprE1 inhibitors to gain deep insights into the chemogenomic space of DprE1-ligand complexes. Physicochemical descriptors of the DprE1 inhibitors showed a marked lipophilic character forming a cluster distinct from the existing TB drugs, as revealed by the principal component analysis. Similarity analysis using Murcko scaffolds and rubber band scaling revealed scarce representation of the chemical space. Further, Murcko scaffold analysis uncovered favorable and unfavorable scaffolds, where benzo and pyridine-based core scaffolds exhibit the highest biological activity, as evidenced by their MIC and IC₅₀ values. Automatic SAR and R-group decomposition analysis resulted in the identification of substructures responsible for the inhibitory activity of the DprE1 enzyme. Further, with activity cliff analysis, we observed prominent discontinuity in the SAR of DprE1 inhibitors, where even simple structural modification in the chemical scaffold resulted in significant potency difference, presumably due to the binding orientation and interaction in the active site. Thiophene, 6-membered aromatic rings, and unsubstituted benzene ring-based toxicophores were identified in the DprE1 chemical space using an artificial intelligence approach based on inductive logic programming. This paper, hence, ushers in new insights for the design and development of potent covalent and non-covalent DprE1 inhibitors and guides hit and lead optimization for the development of non-hazardous small molecule therapeutics for Mycobacterium tuberculosis.

Exploring the therapeutic potential of forkhead box O for outfoxing COVID-19

The COVID-19 pandemic has wreaked unprecedented societal havoc worldwide. The infected individuals may present mild to severe symptoms, with nearly 20% of the confirmed patients impaired with significant complications, including multi-organ failure. Acute respiratory distress imposed by SARS-CoV-2 largely results from an aggravated cytokine storm and deregulated immune response. The forkhead box O (FoxO) transcription factors are reported to play a significant role in maintaining normal cell physiology by regulating survival, apoptosis, oxidative stress, development and maturation of T and B lymphocytes, secretion of inflammatory cytokines, etc. We propose a potent anti-inflammatory approach based on activation of the FoxO as an attractive strategy against the novel coronavirus. This regime will be focused on restoring redox and inflammatory homeostasis along with repair of the damaged tissue, activation of lymphocyte effector and memory cells. Repurposing FoxO activators as a means to alleviate the inflammatory burst following SARS-CoV-2 infection can prove immensely valuable in the ongoing pandemic and provide a reliable groundwork for enriching our repertoire of antiviral modalities for any such complication in the future. Altogether, our review highlights the possible efficacy of FoxO activation as a novel arsenal for clinical management of COVID-19.

Catalytic C-H Bond Activation and Knoevenagel Condensation Using Pyridine-2,3-Dicarboxylate-Based Metal-Organic Frameworks

Three 1D coordination polymers (CPs) [M(pdca)(H2O)2] n (M = Zn, Cd, and Co; 1-3), and a 3D coordination framework {[(CH3)2NH2][CuK(2,3-pdca)(pa)(NO3)2]} n (4) (2,3-pdca = pyridine-2,3-dicarboxylate and pa = picolinic acid), have been synthesized adopting a solvothermal reaction strategy. The CPs have been thoroughly characterized using various spectral techniques, that is, elemental analyses, FT-IR, TGA, DSC, UV/vis, and luminescence. Structural information on 1-4 was obtained by PXRD and X-ray single-crystal analyses, whereas morphological insights were attained through FESEM, AFM, EDX, HRTEM, and BET surface area analyses. Roughness parameters were calculated from AFM analysis, whereas dimensions of small domains and interplanar spacing were defined with the aid of HRTEM. CPs 1-3 are 1D isostructural networks, whereas 4 is a 3D framework. Moreover, 1-4 display moderate luminescence at rt. In addition, 1-4 have been applied as economic and efficient porous catalysts for the Knoevenagel condensation reaction and C-H bond activation under mild conditions with good yields (95-98 and 97-99%), respectively. Notably, 1-3 can be reused up to seven cycles, whereas 4 can be reused up to five catalytic cycles with retained catalytic efficiency. Relative catalytic efficacy toward the Knoevenagel condensation reaction follows in the order 2 > 1 > 3 > 4, whereas 2 > 4 > 1 > 3 for C-H activation. The present result demonstrates synthetic, structural, optical, morphological, and catalytic aspects of 1-4.

Synthesis and Antimalarial Activity of 4-Methylaminoquinoline Compounds against Drug-Resistant Parasite

A series of novel 4-aminoquinoline analogues bearing a methyl group at 4-aminoquinoline moiety were synthesized via a new and robust synthetic route comprising in situ tert-butoxycarbonyl (Boc) deprotection-methylation cascade resulting in the corresponding N-methylated secondary amine using Red-Al and an efficient microwave-assisted strategy for the fusion of N-methylated secondary amine with 4-chloroquinoline nucleus to access the series of novel 4-N-methylaminoquinoline analogues. The new series of compounds were evaluated for their antimalarial activity in in vitro and in vivo models. Among 21 tested compounds, 9a-i have shown a half-maximal inhibitory concentration (IC₅₀) value less than 0.5 μM (i.e., <500 nM) against both chloroquine-sensitive strain 3D7 and chloroquine-resistant strain K1 of Plasmodium falciparum with acceptable cytotoxicity. Based on the in vitro antimalarial activity, selected compounds were screened for their in vivo antimalarial activity against Plasmodium yoelii nigeriensis (a multidrug-resistant) parasite in Swiss mice. Most of the compounds have shown significant inhibition on day 4 post infection at the oral dose of 100 mg/kg. Compound 9a has shown 100% parasite inhibition on day 4, and out of five treated mice, two were cured till the end of the experiment. The present study suggests that 4-methylamino substitution is well tolerated for the antiplasmodial activity with reduced toxicity and therefore will be highly useful for the discovery of a new antimalarial agent against drug-resistant malaria.

PEPN-GRN: A Petri net-based approach for the inference of gene regulatory networks from noisy gene expression data

The inference of gene regulatory networks (GRNs) from expression data is a challenging problem in systems biology. The stochasticity or fluctuations in the biochemical processes that regulate the transcription process poses as one of the major challenges. In this paper, we propose a novel GRN inference approach, named the Probabilistic Extended Petri Net for Gene Regulatory Network (PEPN-GRN), for the inference of gene regulatory networks from noisy expression data. The proposed inference approach makes use of transition of discrete gene expression levels across adjacent time points as different evidence types that relate to the production or decay of genes. The paper examines three variants of the PEPN-GRN method, which mainly differ by the way the scores of network edges are computed using evidence types. The proposed method is evaluated on the benchmark DREAM4 in silico data sets and a real time series data set of E. coli from the DREAM5 challenge. The PEPN-GRN_v3 variant (the third variant of the PEPN-GRN approach) sought to learn the weights of evidence types in accordance with their contribution to the activation and inhibition gene regulation process. The learned weights help understand the time-shifted and inverted time-shifted relationship between regulator and target gene. Thus, PEPN-GRN_v3, along with the inference of network edges, also provides a functional understanding of the gene regulation process.

Photoinduced Enhanced Decomposition of TBHP: A Convenient and Greener Pathway for Aqueous Domino Synthesis of Quinazolinones and Quinoxalines

Catalyst-free photoinduced processes in aqueous medium represent significant advancement toward development of green and sustainable pathways in organic synthesis. tert-Butyl hydroperoxide (TBHP) is a widely used oxidant in organic reactions, where the decomposition of TBHP into its radicals by metal catalysts or other reagents is a key factor for efficient catalytic outcome. Herein, we report a simple and environmentally friendly visible light-promoted synthetic pathway for the synthesis of N-heterocyclic moieties, such as quinazolinones and quinoxalines, in the presence of TBHP as an oxidizing agent in aqueous medium that requires no catalysts/photocatalysts. The enhanced rate of decomposition to generate free radicals from TBHP upon visible light irradiation is the driving force for the domino reaction.

Investigations of plastic contamination of seawater, marine and coastal sediments in the Russian seas: a review

Twelve seas with an integral coastline length of about 38,000 km wash upon the Russian coasts. They belong to the basins of the Atlantic, the Arctic, and the Pacific Oceans and stretch over temperate, subpolar, and polar climate zones. This review of 32 studies published between 2015 and August 2020 analyses the available peer-reviewed scientific publications related to the topic of plastic contamination. At present, plastic contamination of the marine environments is confirmed by field investigations in 7 out of 12 Russian seas. Pollution levels vary widely: from 0.6 to 336,000 items/m3 for microplastics in water and from 1.3 to 10,179 items/kg (DW)-in sediments, while median macroplastics abundance is around 1.0 item/m2 at the coast. One monitoring survey of the Barents Sea reported mean macroplastics concentration in the upper 60 m as 0.011 mg/m3 and 2.9 kg/km2 at the sea floor. The identification of the polymer types with spectroscopy techniques is performed only in 9 studies (28%); most researchers use visual identification which makes the results difficult to compare. Most projects aimed at the plastic contamination research use their own collection and extraction methods that poorly agree with other studies. Since the pollution levels in most of the areas are relatively low, sampling is inhomogeneous in space and time. The most extensively studied areas are the beaches of the Baltic Sea, while the least examined is the Arctic region. Our study highlights the need for a discussion on harmonizing sampling methodology and identification techniques among different studies.

Melatonin Provides Neuroprotection Following Traumatic Brain Injury-Promoted Mitochondrial Perturbation in Wistar Rat

Excessive mitochondrial fission has been implicated in the etiology of neuronal cell death in traumatic brain injury (TBI). In the present study, we examined the efficacy of melatonin (Mel) as a neuroprotective agent against TBI-induced oxidative damage and mitochondrial dysfunction. We assessed the impact of Mel post-treatment (10 mg/kg b.wt., i.p.) at different time intervals in TBI-subjected Wistar rats. We found that the Mel treatment significantly attenuated brain edema, oxidative damage, mitochondrial fission, and promoted mitochondrial fusion. Additionally, Mel-treated rats showed restoration of mitochondrial membrane potential and oxidative phosphorylation with a concomitant reduction in cytochrome-c release. Further, Mel treatment significantly inhibited the translocation of Bax and Drp1 proteins to mitochondria in TBI-subjected rats. The restorative role of Mel treatment in TBI rats was supported by the mitochondrial ultra-structural analysis, which showed activation of mitochondrial fusion mechanism. Mel enhanced mitochondrial biogenesis by upregulation of PGC-1α protein. Our results demonstrated the remedial role of Mel in ameliorating mitochondrial dysfunctions that are modulated in TBI-subjected rats and provided support for mitochondrial-mediated neuroprotection as a putative therapeutic agent in the brain trauma.

Designing of a nanoscale zerovalent iron@fly ash composite as efficient and sustainable adsorbents for hexavalent chromium (Cr(VI)) from water

The present study encompasses a unique concept involving the formation of core-shell particles with surface-activated fly ash (FA) as core and nanoscale zerovalent iron (nZVI) particles as shell, which not only imparts high adsorption efficiency for Cr(VI) but also contributes to fruitful utilization of FA while overcoming the drawbacks associated with ZVI nanoparticles (aggregation, rapid oxidation and less durability). The otherwise inert surface of FA has been modified and activated to achieve a uniform and stable layer of nZVI over FA. The functionalized particles were studied using FE-SEM/EDAX, HR-TEM, XRD and FT-IR studies for its physical, functional and morphological characteristics. The results indicate the strong adsorption ability of nZVI@FA particles, with 100% removal efficiency within 10 min at low initial concentrations of Cr(VI), which is appreciably higher than that of pure fly ash (26%) after 60 min of reaction. Besides, the so-formed structure of composite aids to improve its life, as the synthesized nZVI@FA particles could be efficiently regenerated and reused up to 5 subsequent adsorption-desorption cycles, which is in contrast with the ability of fly ash considering its low desorption potential. Hence, the composite material proves to be an effective and sustainable alternative for treatment of a waste using a waste.

TNF-α differentially modulates subunit levels of respiratory electron transport complexes of ER/PR +ve/-ve breast cancer cells to regulate mitochondrial complex activity and tumorigenic potential

BACKGROUND

Tumor necrosis factor-α (TNF-α) is an immunostimulatory cytokine that is consistently high in the breast tumor microenvironment (TME); however, its differential role in mitochondrial functions and cell survival in ER/PR +ve and ER/PR -ve breast cancer cells is not well understood.

METHODS

In the current study, we investigated TNF-α modulated mitochondrial proteome using high-resolution mass spectrometry and identified the differentially expressed proteins in two different breast cancer cell lines, ER/PR positive cell line; luminal, MCF-7 and ER/PR negative cell line; basal-like, MDA-MB-231 and explored its implication in regulating the tumorigenic potential of breast cancer cells. We also compared the activity of mitochondrial complexes, ATP, and ROS levels between MCF-7 and MDA-MB-231 in the presence of TNF-α. We used Tumor Immune Estimation Resource (TIMER) webserver to analyze the correlation between TNF-α and mitochondrial proteins in basal and luminal breast cancer patients. Kaplan-Meier method was used to analyze the correlation between mitochondrial protein expression and survival of breast cancer patients.

RESULTS

The proteome analysis revealed that TNF-α differentially altered the level of critical proteins of mitochondrial respiratory chain complexes both in MCF-7 and MDA-MB-231, which correlated with differential assembly and activity of mitochondrial ETC complexes. The inhibition of the glycolytic pathway in the presence of TNF-α showed that glycolysis is indispensable for the proliferation and clonogenic ability of MDA-MB-231 cells (ER/PR -ve) as compared to MCF-7 cells (ER/PR +ve). The TIMER database showed a negative correlation between the expressions of TNF-α and key regulators of mitochondrial OXPHOS complexes in basal breast vs lobular carcinoma. Conversely, patient survival analysis showed an improved relapse-free survival with increased expression of identified proteins of ETC complexes and survival of the breast cancer patients.

CONCLUSION

The evidence presented in our study convincingly demonstrates that TNF-α regulates the survival and proliferation of aggressive tumor cells by modulating the levels of critical assembly factors and subunits involved in mitochondrial respiratory chain supercomplexes organization and function. This favors the rewiring of mitochondrial metabolism towards anaplerosis to support the survival and proliferation of breast cancer cells. Collectively, the results strongly suggest that TNF-α differentially regulates metabolic adaptation in ER/PR +ve (MCF-7) and ER/PR -ve (MDA-MB-231) cells by modulating the mitochondrial supercomplex assembly and activity.

Bioinspired Brønsted Acid-Promoted Regioselective Tryptophan Isoprenylations

Tryptophan-containing isoprenoid indole alkaloid natural products are well known for their intricate structural architectures and significant biological activities. Nature employs dimethylallyl tryptophan synthases (DMATSs) or aromatic indole prenyltransferases (iPTs) to catalyze regio- and stereoselective prenylation of l-Trp. Regioselective synthetic routes that isoprenylate cyclo-Trp-Trp in a 2,5-diketopiperazine (DKP) core, in a desymmetrizing manner, are nonexistent and are highly desirable. Herein, we present an elaborate report on Brønsted acid-promoted regioselective tryptophan isoprenylation strategy, applicable to both the monomeric amino acid and its dimeric l-Trp DKP. This report outlines a method that regio- and stereoselectively increases sp3 centers of a privileged bioactive core. We report on conditions involving screening of Brønsted acids, their conjugate base as salt, solvent, temperature, and various substrates with diverse side chains. Furthermore, we extensively delineate effects on regio- and stereoselection of isoprenylation and their stereochemical confirmation via NMR experiments. Regioselectively, the C3-position undergoes normal-isoprenylation or benzylation and forms exo-ring-fused pyrroloindolines selectively. Through appropriate prenyl group migrations, we report access to the bioactive tryprostatin alkaloids, and by C3-normal-farnesylation, we access anticancer drimentines as direct targets of this method. The optimized strategy affords iso-tryprostatin B-type products and predrimentine C with 58 and 55% yields, respectively. The current work has several similarities to biosynthesis, such as-reactions can be performed on unprotected substrates, conditions that enable Brønsted acid promotion, and they are easy to perform under ambient conditions, without the need for stoichiometric levels of any transition metal or expensive ligands.

Crossover of positive and negative magnetoconductance in composites of nanosilica glass containing dual transition metal oxides

A facile sol-gel approach to prepare composites of nanosilica glass containing dual transition metal oxides with compositions xCoO·(20 - x)NiO·80SiO2 comprising x values 5 (NC-1), 10 (NC-2) and 15 (NC-3) within hexagonal pores of SBA-15 template has been demonstrated. The synergistic effect of dual transition metal oxide ions on MD properties and crossover of positive and negative magnetoconductance phenomena were observed in these nanocomposite systems. The physical origin of magnetoconductance switching is explained based on the factors: nanoconfinement effect, wave-function shrinkage and spin polarized electron hopping. DFT calculations were performed to understand the structural correlation of the nanoconfined system. The static (dc) and dynamic (ac) responses of magnetization revealed the spin-glass behaviour of the investigated samples. Both scaling law and Vogel-Fulcher law provide a satisfactory fit to our experimental results which are considered as a salient feature of the spin-glass system. Our studies indicate the possibilities of fabricating magnetically controlled multifunctional devices.

Coordination between nucleotide excision repair and specialized polymerase DnaE2 action enables DNA damage survival in non-replicating bacteria

Translesion synthesis (TLS) is a highly conserved mutagenic DNA lesion tolerance pathway, which employs specialized, low-fidelity DNA polymerases to synthesize across lesions. Current models suggest that activity of these polymerases is predominantly associated with ongoing replication, functioning either at or behind the replication fork. Here we provide evidence for DNA damage-dependent function of a specialized polymerase, DnaE2, in replication-independent conditions. We develop an assay to follow lesion repair in non-replicating Caulobacter and observe that components of the replication machinery localize on DNA in response to damage. These localizations persist in the absence of DnaE2 or if catalytic activity of this polymerase is mutated. Single-stranded DNA gaps for SSB binding and low-fidelity polymerase-mediated synthesis are generated by nucleotide excision repair (NER), as replisome components fail to localize in the absence of NER. This mechanism of gap-filling facilitates cell cycle restoration when cells are released into replication-permissive conditions. Thus, such cross-talk (between activity of NER and specialized polymerases in subsequent gap-filling) helps preserve genome integrity and enhances survival in a replication-independent manner.

COVID-19 outbreak: history, mechanism, transmission, structural studies and therapeutics

PURPOSE

The coronavirus outbreak emerged as a severe pandemic, claiming more than 0.8 million lives across the world and raised a major global health concern. We survey the history and mechanism of coronaviruses, and the structural characteristics of the spike protein and its key residues responsible for human transmissions.

METHODS

We have carried out a systematic review to summarize the origin, transmission and etiology of COVID-19. The structural analysis of the spike protein and its disordered residues explains the mechanism of the viral transmission. A meta-data analysis of the therapeutic compounds targeting the SARS-CoV-2 is also included.

RESULTS

Coronaviruses can cross the species barrier and infect humans with unexpected consequences for public health. The transmission rate of SARS-CoV-2 infection is higher compared to that of the closely related SARS-CoV infections. In SARS-CoV-2 infection, intrinsically disordered regions are observed at the interface of the spike protein and ACE2 receptor, providing a shape complementarity to the complex. The key residues of the spike protein have stronger binding affinity with ACE2. These can be probable reasons for the higher transmission rate of SARS-CoV-2. In addition, we have also discussed the therapeutic compounds and the vaccines to target SARS-CoV-2, which can help researchers to develop effective drugs/vaccines for COVID-19. The overall history and mechanism of entry of SARS-CoV-2 along with structural study of spike-ACE2 complex provide insights to understand disease pathogenesis and development of vaccines and drugs.

Elucidating Methods for Isolation and Quantification of Exosomes: A Review

Exosomes are the smallest extracellular vesicles present in most of the biological fluids. They are found to play an important role in cell signaling, immune response, tumor metastasis, etc. Studies have shown that these vesicles also have diagnostic and therapeutic roles for which their accurate detection and quantification is essential. Due to the complexity in size and structure of exosomes, even the gold standard methods face challenges. This comprehensive review discusses the various standard methods such as ultracentrifugation, ultrafiltration, size-exclusion chromatography, precipitation, immunoaffinity, and microfluidic technologies for the isolation of exosomes. The principle of isolation of each method is described, as well as their specific advantages and disadvantages. Quantification of exosomes by nanoparticle tracking analysis, flow cytometry, tunable resistive pulse sensing, electron microscopy, dynamic light scattering, and microfluidic devices are also described, along with the applications of exosomes in various biomedical domains.

Magnetic gas sensing: working principles and recent developments

Gas sensors work on the principle of transforming the gas adsorption effects on the surface of the active material into a detectable signal in terms of its changed electrical, optical, thermal, mechanical, magnetic (magnetization and spin), and piezoelectric properties. In magnetic gas sensors, the change in the magnetic properties of the active materials is measured by one of the approaches such as Hall effect, magnetization, spin orientation, ferromagnetic resonance, magneto-optical Kerr effect, and magneto-static wave oscillation effect. The disadvantages of different types of gas sensors include their chemical selectivity and sensitivity to humidity and high-temperature operation. For example, in the case of chemiresistive-type gas sensors, the change in the sensor resistance can drastically vary in the real environment due to the presence of other gas species and the overall electrical effect is quite complex due to simultaneous surface reactions. Further, it is not easy to make stable contacts for powdered samples for the conventional electrical property-based gas sensors. Fire hazard is another issue for the electrical property-based hydrogen gas sensors due to their flammable nature at higher operating temperature. In this regard, to solve these issues, magnetic gas sensor concepts have emerged, in which the magnetic properties of the materials get modified when exposed to gas molecules. In this review article, the working principles, fundamentals, recent developments, and future perspectives in magnetic gas sensors are reviewed. Finally, the prospects and opportunities in these exciting fields are also commented upon based on their current progress.

Compromised base excision repair pathway in Mycobacterium tuberculosis imparts superior adaptability in the host

Tuberculosis caused by Mycobacterium tuberculosis (Mtb) is a significant public health concern, exacerbated by the emergence of drug-resistant TB. To combat the host’s dynamic environment, Mtb encodes multiple DNA repair enzymes that play a critical role in maintaining genomic integrity. Mtb possesses a GC-rich genome, rendering it highly susceptible to cytosine deaminations, resulting in the occurrence of uracils in the DNA. UDGs encoded by ung and udgB initiate the repair; hence we investigated the biological impact of deleting UDGs in the adaptation of pathogen. We generated gene replacement mutants of uracil DNA glycosylases, individually (RvΔung, RvΔudgB) or together (RvΔdKO). The double KO mutant, RvΔdKO exhibited remarkably higher spontaneous mutation rate, in the presence of antibiotics. Interestingly, RvΔdKO showed higher survival rates in guinea pigs and accumulated large number of SNPs as revealed by whole-genome sequence analysis. Competition assays revealed the superior fitness of RvΔdKO over Rv, both in ex vivo and in vivo conditions. We propose that compromised DNA repair results in the accumulation of mutations, and a subset of these drives adaptation in the host. Importantly, this property allowed us to utilize RvΔdKO for the facile identification of drug targets.

Mutation in the genome of bacteria contributes to the acquisition of drug resistance. Mutations in bacteria can arise due to exposures to antibiotics, oxidative, reductive, and many other stresses that bacteria encounter in the host. Mtb has multiple DNA repair mechanisms, including a base excision repair pathway to restore the damaged genome. Here we set out to determine the impact of deleting the Uracil DNA base excision pathway on pathogen adaptability to both antibiotic and host induced stresses. Combinatorial mutant of Mtb UDGs showed higher spontaneous rates of mutations when subjected to antibiotic stress and showed higher survival levels in the guinea pig model of infection. Whole-genome sequence analysis showed significant accumulation of SNPs, suggesting that mutations providing survival advantage may have been positively selected. We also showed that double mutant of Mtb UDGs would be an excellent means to identify antibiotic targets in the bacteria. Competition experiments wherein we pitted wild type and double mutant against each other demonstrated that double mutant has a decisive edge over the wild type. Together, data suggest that the absence of a base excision repair pathway leads to higher mutations and provides a survival advantage under stress. They could be an invaluable tool for identifying targets of new antibiotics.

Antagonistic roles for Ataxin-2 structured and disordered domains in RNP condensation

Ataxin-2 (Atx2) is a translational control molecule mutated in spinocerebellar ataxia type II and amyotrophic lateral sclerosis. While intrinsically disordered domains (IDRs) of Atx2 facilitate mRNP condensation into granules, how IDRs work with structured domains to enable positive and negative regulation of target mRNAs remains unclear. Using the Targets of RNA-Binding Proteins Identified by Editing technology, we identified an extensive data set of Atx2-target mRNAs in the Drosophila brain and S2 cells. Atx2 interactions with AU-rich elements in 3'UTRs appear to modulate stability/turnover of a large fraction of these target mRNAs. Further genomic and cell biological analyses of Atx2 domain deletions demonstrate that Atx2 (1) interacts closely with target mRNAs within mRNP granules, (2) contains distinct protein domains that drive or oppose RNP-granule assembly, and (3) has additional essential roles outside of mRNP granules. These findings increase the understanding of neuronal translational control mechanisms and inform strategies for Atx2-based interventions under development for neurodegenerative disease.

Biodiversity of meatborne Listeria spp. in Himachal Pradesh and their interaction with indigenous probiotics

This study determined the anti-listerial activity of indigenous probiotics from traditional fermented foods of Western Himalaya against meat borne Listera monocytogens isolates from Himachal Pradesh. One hundred samples of meat and meat products like chicken (n = 25), chevon (goat meat, n = 20), fish (n = 20) and pork (n = 30) were collected and were analyzed for the presence of Listeria spp. by recommended culture and biochemical methods. L. monocytogens isolates were confirmed by PCR targeting the virulence gene hlyA (haemolysin A) and by16S rRNA sequencing. Anti-listerial activity of probiotic bacteria isolated from indigenous fermented foods of Himachal Pradesh was determined by well diffusion method using Lactobacillus rhamnosus GG (ATCC 53103) as the reference strain. Five percent of tested samples were found positive for L. monocytogens with incidence of 8.0% in chicken (2/25), 10.0% in fish (2/20) and 4.0% in chevon meat (1/25). None of the tested pork samples were found contaminated with L. monocytogenes. Among 11 indigenous probiotics used in this study, highest antagonistic activity was exhibited by Lactobacillus plantarum (ADF 10) and Enterococcus faecium (ADF1) which was equivalent to the reference strain.

Factors Affecting Bacterial Adhesion on Selected Textile Fibres

In sectors like healthcare and hospitality, it has been realized that fabrics play a pivotal role in transfer of nosocomial infections. However, there is a major gap in drawing correlation between different fibre types and their interaction with microorganisms. Such information is important to formulate guidelines for textile materials for use in these sectors. In the current study, the adherence of four important bacteria, Staphylococcus aureus, Acinetobacter calcoaceticus, Escherichia coli, and Pseudomonas aeruginosa was studied on six different fibre types namely polyester, wool, polypropylene, viscose, silk and cotton. Among these fibres, viscose showed maximum adherence while silk fibres showed the least attachment of bacterial strains. Bacterial adhesion was correlated with the surface characteristics (surface charge, hydrophobicity etc.) of bacteria, and nanoroughness of fibres. Adhesion of these bacteria was tested on five hydrocarbons of different hydrophobicities. E. coli, the weakest biofilm producer, and with the highest surface energy and lowest hydrophobicity amongst the bacteria compared in the study, had the lowest load on all fibres. Scanning electron microscopy revealed non-uniform binding of gram-negative and gram-positive bacteria. Nanoroughness of fibres favored bacterial adhesion. The study showed correlation between surface properties and adherence of bacteria on fibres, with the results being of direct significance to medical and hospitality sectors.