Cytochrome bd oxidase: an emerging anti-tubercular drug target

Cytochrome bd (cyt-bd) oxidase, one of the two terminal oxidases in the Mycobacterium tuberculosis (Mtb) oxidative phosphorylation pathway, plays an indispensable role in maintaining the functionality of the metabolic pathway under stressful conditions. However, the absence of this oxidase in eukaryotic cells allows researchers to select it as a potential drug target for the synthesis of anti-tubercular (anti-TB) molecules. Cyt-bd inhibitors have often been combined with cytochrome bcc/aa3 super-complex inhibitors in anti-TB drug regimens to achieve a desired bactericidal response. The functional redundancy between both the terminal oxidases is responsible for this. The cryo-EM structure of cyt-bd oxidase from Mtb (PDB ID: 7NKZ) further accelerated the research to identify its inhibitor. Herein, we have summarized the reported anti-TB cyt-bd inhibitors, insight into the rationale behind targeting cyt-bd oxidase, and an outline of the architecture of Mtb cyt-bd oxidase.

Synthesis of imidazole-fused nitrogen-bridgehead heterocycles catalysed by lipase and their antifungal and antimicrobial bioactivity

An effective approach for selective C-N bond formation for synthesising imidazo[1,2-a] pyridine-based heterocycles using porcine pancreatic lipase (PPL) as a biocatalyst has been devised. Under moderate conditions, a series of imidazo[1,2-a]pyridine-based heterocycle derivatives were synthesised with remarkable selectivity in good-to-excellent yields (89-95%). Further, the antimicrobial and antifungal activities of derivatives 3ha, 3ka, 3fa, 3hc, and 3eb were observed, and they were found to be biologically active in antimicrobial susceptibility tests for Gram-positive bacteria (Enterococcus faecalis ATCC 29212 and Staphylococcus auris ATCC 25923), Gram-negative bacteria (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853) and fungal strains (Candida albicans ATCC 90028 and Candida tropicalis ATCC 750).

Delineating the Structure-Dynamics-Binding Differences among BA.1, BA.4/5, and BF.7 SARS-CoV-2 Variants through Atomistic Simulations: Correlation with Structural and Epidemiological Features

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an RNA virus possessing a spike (S) protein that facilitates the entry of the virus into human cells. The emergence of highly transmissible and fit SARS-CoV-2 variants has been driven by the positive selection of mutations within the S-protein. Notable among these variants are alpha, beta, gamma, delta, and omicron (BA.1), with the latter contributing to significant global health challenges and impacting populations worldwide. Recently, a novel subvariant of BA.1, named BF.7, has surfaced, purportedly exhibiting elevated transmissibility and infectivity rates. In order to comprehend and compare the transmissibility and disease progression characteristics of distinct SARS-CoV-2 variants, we performed an extensive comparative analysis utilizing all-atom molecular dynamics (MD) simulations (in triplicate) to investigate the structural, dynamic, and binding features of BA.1, BA.4/5, and BF.7. Our simulation findings, energetic analysis, and assessment of physicochemical properties collectively illuminate the dominance of the BA.1 variant over the others, a trend that is further substantiated by the sustained global prevalence of BA.1 relative to BA.4/5 and BF.7. Additionally, our simulation results align well with the reported cryoelectron microscopy (cryo-EM) structural data and epidemiological characteristics obtained from the Global Initiative on Sharing All Influenza Data (GISAID). This study presents a comprehensive comparative elucidation of the critical structural, dynamic, and binding attributes of these variants, providing insights into the predominance of BA.1 and its propensity to continuously generate numerous novel subvariants.

Conjugated Nanoparticles for Solid Tumor Theranostics: Unraveling the Interplay of Known and Unknown Factors

Cancer diagnoses have been increasing worldwide, and solid tumors are among the leading contributors to patient mortality, creating an enormous burden on the global healthcare system. Cancer is responsible for around 10.3 million deaths worldwide. Solid tumors are one of the most prevalent cancers observed in recent times. On the other hand, early diagnosis is a significant challenge that could save a person's life. Treatment with existing methods has pitfalls that limit the successful elimination of the disorder. Though nanoparticle-based imaging and therapeutics have shown a significant impact in healthcare, current methodologies for solid tumor treatment are insufficient. There are multiple complications associated with the diagnosis and management of solid tumors as well. Recently, surface-conjugated nanoparticles such as lipid nanoparticles, metallic nanoparticles, and quantum dots have shown positive results in solid tumor diagnostics and therapeutics in preclinical models. Other nanotheranostic material platforms such as plasmonic theranostics, magnetotheranostics, hybrid nanotheranostics, and graphene theranostics have also been explored. These nanoparticle theranostics ensure the appropriate targeting of tumors along with selective delivery of cargos (both imaging and therapeutic probes) without affecting the surrounding healthy tissues. Though they have multiple applications, nanoparticles still possess numerous limitations that need to be addressed in order to be fully utilized in the clinic. In this review, we outline the importance of materials and design strategies used to engineer nanoparticles in the treatment and diagnosis of solid tumors and how effectively each method overcomes the drawbacks of the current techniques. We also highlight the gaps in each material platform and how design considerations can address their limitations in future research directions.

Recent advances of nanocrystals in cancer theranostics

Emerging cancer cases across the globe and treating them with conventional therapies with multiple limitations have been challenging for decades. Novel drug delivery systems and alternative theranostics are required for efficient detection and treatment. Nanocrystals (NCs) have been established as a significant cancer diagnosis and therapeutic tool due to their ability to deliver poorly water-soluble drugs with sustained release, low toxicity, and flexibility in the route of administration, long-term sustainable drug release, and noncomplicated excretion. This review summarizes several therapies of NCs, including anticancer, immunotherapy, radiotherapy, biotheranostics, targeted therapy, photothermal, and photodynamic. Further, different imaging and diagnostics using NCs are mentioned, including imaging, diagnosis through magnetic resonance imaging (MRI), computed tomography (CT), biosensing, and luminescence. In addition, the limitations and potential solutions of NCs in the field of cancer theranostics are discussed. Preclinical and clinical data depicting the importance of NCs in the spotlight of cancer, its current status, future aspects, and challenges are covered in detail.

Morphological dependent exciton dynamics and thermal transport in MoSe2 films

Thermal transport and exciton dynamics of semiconducting transition metal dichalcogenides (TMDCs) play an immense role in next-generation electronic, photonic, and thermoelectric devices. In this work, we synthesize distinct morphologies (snow-like and hexagonal) of a trilayer MoSe₂ film over the SiO₂/Si substrate via the chemical vapor deposition (CVD) method and investigated their morphological dependent exciton dynamics and thermal transport behaviour for the first time to the best of our knowledge. Firstly, we studied the role of spin-orbit and interlayer couplings both theoretically as well as experimentally via first-principles density functional theory and photoluminescence study, respectively. Further, we demonstrate morphological dependent thermal sensitive exciton response at low temperatures (93-300 K), showing more dominant defect-bound excitons (E_L) in snow-like MoSe₂ compared to hexagonal morphology. We also examined the morphological-dependent phonon confinement and thermal transport behaviour using the optothermal Raman spectroscopy technique. To provide insights into the nonlinear temperature-dependent phonon anharmonicity, a semi-quantitative model comprising volume and temperature effects was used, divulging the dominance of three-phonon (four-phonon) scattering processes for thermal transport in hexagonal (snow-like) MoSe₂. The morphological impact on thermal conductivity (k_s) of MoSe₂ has also been examined here by performing the optothermal Raman spectroscopy, showing k_s ∼ 36 ± 6 W m^-1 K^-1 for snow-like and ∼41 ± 7 W m^-1 K^-1 for hexagonal MoSe₂. Our research will contribute to the understanding of thermal transport behaviour in different morphologies of semiconducting MoSe₂, finding suitability for next-generation optoelectronic devices.

Intranasally Co-administered Berberine and Curcumin Loaded in Transfersomal Vesicles Improved Inhibition of Amyloid Formation and BACE-1

Selective permeability of the blood-brain barrier restricts the treatment efficacy of neurologic diseases. Berberine (BBR) and curcumin (CUR)-loaded transferosomes (TRANS) were prepared for the effective management of Alzheimer's disease (AD). The study involved the syntheses of BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS by the film hydration method. Vesicles were characterized to ensure the formation of drug-loaded vesicles and their in vivo performance. The particle sizes of BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS were 139.2 ± 7, 143.4 ± 8, and 165.3 ± 6.5 nm, respectively. The presence of diffused rings in the SED image indicates the crystalline nature of the payload. Low surface roughness in an AFM image could be associated with the presence of a surface lipid. BBR-CUR-TRANS showed 41.03 ± 1.22 and 47.79 ± 3.67% release of BBR and 19.22 ± 1.47 and 24.67 ± 1.94% release of CUR, respectively, in phosphate buffer saline (pH 7.4) and acetate buffer (pH 4.0). Formulations showed sustained release of both loaded drugs. BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS exhibited a lower percentage of hemolysis than pure BBR and CUR, indicating the safety of the payload from delivery vesicles. Lower percentages of binding were recorded from BBR-CUR-TRANS than BBR-TRANS and CUR-TRANS. Acetylcholinesterase inhibition activity of the prepared transferosomes was greater than that of pure drugs, which are thought to have good cellular penetration. The spatial memory was improved in treated mice models. The level of malondialdehyde decreased in AD animals treated with BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS, respectively, as compared to the scopolamine-induced AD animals. BBR-CUR-TRANS-treated animals showed the highest decrease in the NO level. The catalase level was significantly restored in scopolamine-intoxicated animals treated with BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS. The immunohistochemistry result suggested that the BBR-TRANS, CUR-TRANS, and BBR-CUR-TRANS have significantly decreased the regulation of expression of BACE-1 through antioxidant activity. In conclusion, the study highlights the utility of formulated transferosomes as promising carriers for the co-delivery of drugs to the brain.

Evaluation of (Anti)androgenic Activities of Environmental Xenobiotics in Milk Using a Human Liver Cell Line and Androgen Receptor-Based Promoter-Reporter Assay

The recent reports on milk consumption and its associated risk with hormone related disorders necessitates the evaluation of dairy products for the presence of endocrine disrupting chemicals (EDCs) and ensure the safety of consumers. In view of this, we investigated the possible presence of (anti)androgenic contaminants in raw and commercialized milk samples. For this purpose, a novel HepARE-Luc cell line that stably expresses human androgen receptor (AR) and the androgen responsive luciferase reporter gene was generated and used in the present study. Treatment of this cell line with androgens and corresponding antiandrogen (flutamide) stimulated or inhibited expression of reporter luciferase, respectively. Real time polymerase chain reaction and immunostaining results exhibited transcription response and translocation of AR from the cytoplasm to the nucleus in response to androgen. Observations implied that a cell-based xenobiotic screening assay via AR response can be conducted for assessing the (anti)androgenic ligands present in food chain including milk. Therefore, the cell line was further used to screen the (anti)androgenic activity of a total of 40 milk fat samples procured as raw or commercial milk. Some of the raw and commercial milk fat samples distinctly showed antiandrogenic activities. Subsequently, some commonly used environmental chemicals were also evaluated for their (anti)androgenic activities. Initial observations with molecular docking studies of experimental compounds were performed to assess their interaction with AR ligand binding domain. Furthermore, (anti)androgenic activities of these compounds were confirmed by performing luciferase assay using the HepARE-Luc cell line. None of the test compounds showed androgenic activities rather some of them like Bisphenol A (BPA) and rifamycin showed antiandrogenic activities. In conclusion, our results provide a valuable information about the assessment of (anti)androgenic activities present in milk samples. Overall, it is proposed that a robust cell-based CALUX assay can be used to assess the (anti)androgenic activities present in milk which can be attributed to different environmental chemicals present therein.

Antiproliferative Potential of Gloriosine: A Lead for Anticancer Drug Development

Gloriosine, a colchicine-like natural product, is widely obtained from Gloriosa superba roots. Despite having remarkable anticancer potential, colchicine could not pave its way to the clinic, while gloriosine is yet to be investigated for its pharmacological effects. In the present work, 14 compounds, including gloriosine, were isolated from the G. superba roots and were characterized by NMR spectroscopy. Gloriosine (11) was evaluated for its antiproliferative activity against a panel of 15 human cancer cell lines of different tissues and normal breast cells. Gloroisine (11) displayed significant antiproliferative activity against various cancer cell lines selectively, with IC₅₀ values ranging from 32.61 to 100.28 nM. Further, gloriosine (11) was investigated for its apoptosis-inducing ability and found to form apoptotic bodies. It also inhibited A549 cell migration in the wound healing assay. Finally, molecular docking studies were performed to explore the possible binding modes of gloriosine with the colchicine-binding site of tubulin protein. Our findings suggested that gloriosine might be a potential lead for anticancer drug discovery.

Exploring the Potential of Chemical Inhibitors for Targeting Post-translational Glycosylation of Coronavirus (SARS-CoV-2)

The Spike (S) protein of SARS-CoV-2 expressed on the viral cell surface is of particular importance as it facilitates viral entry into the host cells. The S protein is heavily glycosylated with 22 N-glycosylation sites and a few N-glycosylation sites. During the viral surface protein synthesis via the host ribosomal machinery, glycosylation is an essential step in post-translational modifications (PTMs) and consequently vital for its life cycle, structure, immune evasion, and cell infection. Interestingly, the S protein of SARS-CoV-2 and the host receptor protein, ACE2, are also extensively glycosylated and these surface glycans are critical for the viral-host cell interaction for viral entry. The glycosylation pathway of both virus (hijacked from the host biosynthetic machinery) and target cells crucially affect SARS-CoV-2 infection at different levels. For example, the glycosaminoglycans (GAGs) of host cells serve as a cofactor as they interact with the receptor-binding domain (RBD) of S-glycoprotein and play a protective role in host immune evasion via masking the viral peptide epitopes. Hence, the post-translational glycan biosynthesis, processing, and transport events could be potential targets for developing therapeutic drugs and vaccines. Especially, inhibition of the N-glycan biosynthesis pathway amplifies S protein proteolysis and, thus, blocks viral entry. The chemical inhibitors of SARS-CoV-2 glycosylation could be evaluated for Covid-19. In this review, we discuss the current status of the chemical inhibitors (both natural and synthetically designed inhibitors) of viral glycosylation for Covid-19 and provide a future perspective. It could be an important strategy in targeting the various emerging SARS-CoV-2 variants of concern (VOCs), as these inhibitors are postulated to aid in reducing the viral load as well as infectivity.

Functionalized polyurethane composite gel electrolyte with cosensitized photoanode for higher solar cell efficiency using a passivation layer

Graphene oxide was chemically tagged with thermoplastic polyurethane, chain extended using butanediol to obtain the varying molecular weight of the polymer. Graphene-tagged polyurethane was functionalized using propane sultone to introduce the polar sulphonate groups in the main chain. The chain extension, tagging of GO and functionalization have been verified through spectroscopic techniques such as NMR, FTIR, UV and gel permeation chromatography. Thermal stability and the nature of the interaction were explored through thermal measurements to understand the effect of GO and functionalization. Electrical conduction was improved by the chemical attachment of graphene with the polymer (5.08 × 10^-7 S cm^-1), which further increases through functionalization and subsequent use of the additive (1.07 × 10^-3 S cm^-1) and make them suitable for gel electrolyte, being in the range of semiconductors. Quantum dots of CdS and CdSe were prepared using a capping agent and their characteristic properties and dimensions were worked out for their suitability as active materials in a solar cell. The optical band gap of quantum dots and HOMO/LUMO band structure of functionalized polyurethanes were measured using UV-vis and cyclic voltammetry, and thereby, constructing the overall energy diagrams for a possible combination of materials. Conducting carbon has been incorporated in the gel electrolyte to modulate the conductivity, while the ZnSe layer has been inserted as a passivation layer between the active material and the gel electrolyte. Solar cell devices were fabricated using the suitable materials, through the suitable energy diagram, and found a significantly high power conversion efficiency of 1.71%. The reason behind the improved efficiency is understood from the greater light harvesting behaviour, higher level of conductivity and blocking capacity of the various layered structures to reduce the electron-hole pair recombination.

Synthesis, Characterization, and Ionic Conductivity Studies of Simultaneously Substituted K- and Ga-Doped BaZrO3

Ceramic fuel cells possess tremendous advantages over PMFCs due to their fuel flexibility and requirement of low-purity hydrogen. Despite high conversion efficiency, the high cost of ultra high-purity hydrogen required for the operation limits the application of PMFCs. Although ceramic fuel cells operate at elevated temperature, high performance coupled with multifuel flexibility makes ceramic fuel cells a superior option as a static power source to generate electricity compared to thermal coal-fired power plants. BaZr_1-x Y _x O_3-x/2 based protonic conductors get a high degree of interest due to their superior structural stability, but their poor conductivity at higher temperature limits the performance of ceramic fuel cells. To overcome the low ionic conductivity issues of BaZrO₃ based materials at elevated temperature, the simultaneous doping of smaller Ga on the Zr site and K on the Ba site was employed here to create higher concentration of oxide-ion vacancies for the realization of superior conductivities. The simultaneous substitution of K and Ga created the oxygen vacancy-type point defects resulting in higher ionic conductivity ∼10^-2 S/cm above 650 °C. The conductivity represented here for the Ba_0.8K_0.2Zr_0.8Ga_0.2O_2.8 sample is superior or equivalent to the conductivity obtained for yttria-stabilized zirconia, a well-known ceramic oxide-ion electrolyte.