Role of Algal-derived Bioactive Compounds in Human Health.

Algae is emerging as a bioresource with high biological potential. Various algal strains have been used in traditional medicines and human diets worldwide. They are a rich source of bioactive compounds like ascorbic acid, riboflavin, pantothenate, biotin, folic acid, nicotinic acid, phycocyanins, gamma-linolenic acid (GLA), adrenic acid (ARA), docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), etc. Beta-carotene, astaxanthin, and phycobiliproteins are different classes of pigments that are found in algae. They possess antioxidant, anti-inflammatory and anticancer properties. The sulfur-coated polysaccharides in algae have been used as an anticancer, antibacterial, and antiviral agent. Scientists have exploited algal-derived bioactive compounds for developing lead molecules against several diseases. Due to the surge in research on bioactive molecules from algae, industries have started showing interest in patenting for the large-scale production of bioactive compounds having applications in sectors like pharmaceuticals, food, and beverage. In the food industry, algae are used as a thickening, gelling, and stabilizing agent. Due to their gelling and thickening characteristics, the most valuable algae products are macroalgal polysaccharides such as agar, alginates, and carrageenan. The high protein, lipid, and nutrient content in microalgae makes it a superfood for aquaculture. The present review aims at describing various non-energy-based applications of algae in pharmaceuticals, food and beverage, cosmetics, and nutraceuticals. This review attempts to analyze information on algal-derived drugs that have shown better potential and reached clinical trials.

Multidisciplinary approach to community engagement in global public health research.

  Recently, there has been a renewed interest in the role of community engagement in knowledge production and ethical issues such as 'helicopter research', indicating exploitative research activities of some researchers as well as short-term relationships with research communities especially in low- and middle-income countries. This approach is detrimental to both communities and the larger scientific community as this may breed mistrust. Major institutions such as the National Institute of Health and Care Research in the United Kingdom have highlighted the importance of community engagement as a tool to improve the reach, quality, and impact of the research by incorporating the voices and concerns of marginalized communities. Similarly, in its 2022 guidance, the American Society for Human Genetics (ASGH) highlights the need to address underrepresentation in genomics research through community engagement. Establishing ethical and meaningful long-term relationships can be challenging especially for researchers who are not members of the community or those from other countries. This article describes how 'community-engaged research' can address some ethical challenges in global public health in different cultural settings.

Unusual weak and delayed GTPase activity of FtsZ from human pathogenic bacteria Helicobacter pylori.

Actively treadmilling FtsZ acts as the pivotal scaffold for bacterial cell divisome components providing them with a circumferential ride along the site of future division. FtsZ from slow growing Helicobacter pylori (HpFtsZ), a class I carcinogen which thrives abundantly in the acidic environment is poorly understood. We studied HpFtsZ as a function of pH, cations and time and compared it with well-studied E. coli FtsZ (EcFtsZ). HpFtsZ shows pH dependent GTPase activity which is inhibited under acidic conditions. Mg+2 ions play an indispensable role in its GTPase activity, however, higher Mg+2 levels negatively affect its activity. As compared to EcFtsZ, HpFtsZ exhibits lower and slower nucleotide hydrolyzing activity. Molecular Dynamics Simulation studies of FtsZ reveal that GTP binding induces a rewiring of the hydrogen bond network which results in reduction of the binding cleft volume leading to the spontaneous release of GTP. The GTPase activity is linked to the extent of reduction in the binding cleft volume, which is also supported by the binding free energy analysis. Evidently, HpFtsZ is a pH sensitive GTPase with low efficiency that may reflect on the overall slow growth rate of H. pylori.

Modulation of carrier conduction in CsPbBr3 perovskite quantum dots with band-aligned electron and hole acceptors.

The lead halide perovskites have emerged as promising materials with intriguing photo-physical properties and have immense potential for photovoltaic applications. A comprehensive study on the kinetics of charge carrier (electron/hole) generation and transfer across the interface is key to realizing their future scope for efficient device engineering. Herein, we investigate the interfacial charge transfer (CT) dynamics in cesium lead halide (CsPbBr3) perovskite quantum dots (PQDs) with energetically favorable electron acceptors, anthraquinone (AQ) and p-benzoquinone (BQ), and hole acceptors such as pyrene and 4-(dimethylamino)pyridine (DMAP). With various steady-state and time-resolved spectroscopic and microscopic measurements, a faster electron transfer rate is estimated for CsPbBr3 PQDs with BQ compared to that of AQ, while a superior hole transfer for DMAP is divulged compared to pyrene. In concurrence with the spectroscopic measurements, conducting atomic force microscopic studies across the electrode-PQD-electrode junction reveals an increment in the conductance of the PQD in the presence of both the electron and hole acceptors. The variation of the density of states calculation in the presence of the hole acceptors offers strong support and validation for faster CT efficiency. The above findings suggest that a careful selection of simple yet efficient molecular arrangements can facilitate rapid carrier transfer, which can be designed as auxiliary layers for smooth CT and help in the engineering of cost-effective photovoltaic devices.

Unraveling the Relevance of Electron and Hole Transfer in Lead Halide Perovskite Nanocrystals on Current Conduction.

Optimization of perovskite-based optoelectronic performance demands prudent engineering in the device architecture with facile transport of generated charge carriers. Herein, we explore the charge transfer (CT) kinetics in perovskite nanocrystals (PNCs), CsPbBr3, with two redox-active quinones, menadione (MD) and anthraquinone (AQ), and its alteration in halide exchanged CsPbCl3. With a series of spectroscopic and microscopic measurements, we infer that both electron and hole transfer (ET-HT) prevail in CsPbCl3 with quinones, resulting in a faster CT, while ET predominates for CsPbBr3. Furthermore, current-sensing atomic force microscopy measurements demonstrate that the conductance across a metal-PNC-metal nanojunction is improved in the presence of quinones. The contributions of ET and HT to current conduction across PNCs are well supported and validated by theoretical calculations of the density of states. These outcomes convey a new perspective on the relevance of ET and HT in the optimal current conduction and optoelectronic device engineering of perovskites.

Deciphering the Relevance of Quantum Confinement in the Optoelectronics of CsPbBr3 Perovskite Nanostructures.

Perovskites (PVKs) have emerged as an exciting class of semiconducting materials owing to their magnificent photophysical properties and been used in solar cells, light-emitting diodes, photodetectors, etc. The growth of multidimensional nanostructures has revealed many exciting alterations in their optoelectronic properties compared to those of their bulk counterparts. In this work, we have spotlighted the influence of quantum confinement in CsPbBr3 PVKs like the quantum dot (PQD), nanoplatelet (PNPL), and nanorod (PNR) on their charge transfer (CT) dynamics with 1,4-naphthoquinone (NPQ). The energy band alignment facilitates the transfer of both electrons and holes in the PNPL to NPQ, enhancing its CT rate, while only electron transfer in the PQD and PNR diminishes CT. The tunneling current across a metal-nanostructure-metal junction for the PNPL is observed to be higher than others. The higher exciton binding energy in the PNPL results in efficient charge transport by enhancing the mobility of the excited-state carrier and its lifetime compared to those of the PNR and PQD.

Ozonation: an Evolving Disinfectant Technology for the Food Industry.

The food processing industry is currently facing challenges in delivering safe, healthy, and high-quality food. Constant monitoring at each step of the supply chain of food is vital to resolve the issue of food contamination. To achieve this aim and to meet consumer prospects, the technologies promoting the concept of clean label food have been widely cherished. Ozonation is one such advanced technology that assists in maintaining food product quality and safety. Its manifold approach and zero-by-product production make it a promising food disinfectant technique. Ozone due to its oxidative property has been widely used in sanitizing, washing, odor removal, water treatment, and in equipment, fruits, vegetable, and meat processing disinfection. Ozonation in foods is done in such a way that no nutritional, sensory, and physicochemical characteristics are altered. In this review, an attempt is made to give an overview of the impact and contribution of ozone as a disinfectant in food processing while comparing it with conventional disinfectants and its overall application in the food industry.

Social Norms Change and Tobacco Use: A Protocol for a Systematic Review and Meta-Analysis of Interventions.

Tobacco use kills more than eight million individuals each year, and results in substantial economic and human capital loss across nations. While effective supply-side solutions to tobacco control exist, these approaches are less effective at promoting cessation among heavy smokers, and less feasible to implement in countries with weaker tobacco control policy environments. Thus, effective demand-side solutions are needed. Shifting social norms around tobacco use is one such promising approach. To this end, a systematic review and meta-analysis of social norms intervention studies to influence tobacco use will be conducted following PRISMA 2020 guidance. Tobacco intervention studies with at least two time points that explicitly mention social norms or social influence as part of an intervention or set of measured variables will be included. Literature sources will comprise PubMed, Scopus, PsycInfo, and the Cochrane Trial Registry, as well as several grey literature sources. Two reviewers will independently screen studies, and risk of bias will be assessed using the Cochrane Risk of Bias 2 and ROBINS-I tools. The primary outcomes will be change in tobacco use and change in social norms. A random-effects meta-analysis will be conducted for both outcomes. Sources of heterogeneity will be explored using meta-regression with key covariates. Non-reporting biases will be explored using funnel plots. PROSPERO: CRD42021251535.

Modulation of aggregation of silk fibroin by synergistic effect of the complex of curcumin and ß-cyclodextrin.

Amyloid aggregation has been associated with numerous human pathological diseases. A recent study has demonstrated that silk fibroin intermittently endorses amyloidogenesis in vivo. In the current study, we explored the propensity of silk fibroin to undergo amyloid-like aggregation and its prevention using an optimized concoction of curcumin with ß-cyclodextrin. Aggregation of silk fibroin resulted in the formation of fibrils with a diameter of ~3.2 nm. However, addition of the optimized concentration of curcumin and ß-cyclodextrin to silk fibroin inhibited aggregation and preserved the random coil conformation even under aggregation inducing conditions, as demonstrated by CD and FTIR spectroscopy. Benzene rings of curcumin interact with the aromatic residues of fibroin via hydrophobic interactions. However, ß-cyclodextrin preferentially interacts with the non-polar residues, which are the core components for nucleation dependent protein aggregation. The present study demonstrates the ability of the concoction of curcumin and ß-cyclodextrin in tuning the self assembly process of fibroin. It also provides a platform to explore the assembly process of nano-fibril and hierarchical structures in vitro along with a novel insight for designing clinically relevant silk-based functional biomaterials.

Helicobacter pylori shows asymmetric and polar cell divisome assembly associated with DNA replisome.

DNA replication and cell division are two fundamental processes in the life cycle of a cell. The majority of prokaryotic cells undergo division by means of binary fission in coordination with replication of the genome. Both processes, but especially their coordination, are poorly understood in Helicobacter pylori. Here, we studied the cell divisome assembly and the subsequent processes of membrane and peptidoglycan synthesis in the bacterium. To our surprise, we found the cell divisome assembly to be polar, which was well-corroborated by the asymmetric membrane and peptidoglycan synthesis at the poles. The divisome components showed its assembly to be synchronous with that of the replisome and the two remained associated throughout the cell cycle, demonstrating a tight coordination among chromosome replication, segregation and cell division in H. pylori. To our knowledge, this is the first report where both DNA replication and cell division along with their possible association have been demonstrated for this pathogenic bacterium.

Identification of putative Z-ring-associated proteins, involved in cell division in human pathogenic bacteria Helicobacter pylori.

Cell division in bacteria is initiated by FtsZ, which forms a Z ring at the middle of the cell, between the nucleoids. The Z ring is stabilized by Z ring-associated proteins (Zaps), which crosslink the FtsZ filaments and provide strength. The deletion of Zaps leads to the elongation phenotype with an abnormal Z ring. The components of cell division in Helicobacter pylori are similar to other gram negative bacteria except for the absence of few components including Zaps. Here, we used HHsearch to identify homologs of the missing cell division proteins and got potential hits for ZapA and ZapB, as well as for few other cell division proteins. We further validated the function of the putative ZapA homolog by genetic complementation, immuno-colocalization and biochemical analysis.

Evaluation of cytotoxic and tumor targeting capability of (177)Lu-DOTATATE-nanoparticles: a trailblazing strategy in peptide receptor radionuclide therapy.

OBJECTIVE: We propose an innovative strategy of nanoparticle-mediated-peptide receptor radionuclide therapy (PRRT) employing PLGA-nanoparticles together with anti-ß-hCG antibodies that can protect kidneys from radiation damage while simultaneously enhancing its tumor targeting and cytotoxic ability for somatostatin receptor (SSR) positive tumors. METHODS: PEG-coated-(177)Lu-DOTATATE-PLGA-nanoparticles (PEG-LuD-NP) were formulated and characterized. In vitro toxicity of these particles was tested on human glioblastoma cell line U87MG over a radiation dose range of 19-78 Gy, using MTT assay and flow cytometry. To further enhance cytotoxicity and test the feasibility of active tumor targeting, apoptosis-inducing anti-ß-hCG monoclonal antibodies were employed in vitro, after confirming expression of ß-hCG on U87MG. In vivo tumor targeting ability of these particles, in comparison to uncoated particles and un-encapsulated (177)Lu-DOTATATE, was assessed by intravenous administration in tumor-induced wistar rats. Rats were first imaged in a gamma camera followed by euthanasia for organ extraction and counting in gamma counter. RESULTS: The particles were spherical in shape with mean diameter of 300 nm. Highest cytotoxicity that could be achieved with PEG-LuD-NP, on radio-resistant U87MG cells, was 35.8 % due to complex cellular response triggered by ionizing radiation. Interestingly, synergistic action of antibodies and PEG-LuD-NP doubled the cytotoxicity (80 %). PEG-LuD-NP showed the highest tumor uptake (4.3 ± 0.46 % ID/g) as compared to (177)Lu-DOTATATE (3.5 ± 0.31 %) and uncoated-(177)Lu-DOTATATE-nanoparticles (3.4 ± 0.35 %) in tumor-inoculated wistar rats (p < 0.001). Renal uptake/retention was decreased 3-4 folds with these particles, resulting in the highest tumor-to-kidney ratio (8.58; p < 0.01) while tumor-to-liver and tumor-to-bone ratios were comparable to un-encapsulated-drug. CONCLUSION: Nanocarrier-mediated-PRRT is an effective way of targeting SSR positive tumors for enhanced cytoxicity and reduced renal radiation dose associated with conventional PRRT. To our knowledge of literature, this is the first study to establish in vitro and in vivo efficacy profile of nanoparticles in PRRT providing a stepping-stone for undergoing and future research endeavors in the direction of abating associated radiation concerns of radionuclide therapy and may offer a paradigm shift in PRRT strategy.

Modulation of Self-Assembly Process of Fibroin: An Insight for Regulating the Conformation of Silk Biomaterials.

Controlling the mechanism of self-assembly in proteins has emerged as a potent tool for various biomedical applications. Silk fibroin self-assembly consists of gradual conformational transition from random coil to ß-sheet structure. In this work we elucidated the intermediate secondary conformation in the presence of Ca(2+) ions during fibroin self-assembly. The interaction of fibroin and calcium ions resulted in a predominantly α-helical intermediate conformation, which was maintained to certain extent even in the final conformation as illustrated by circular dichroism and attenuated total reflectance-Fourier transform infrared spectroscopy. Further, to elucidate the mechanism behind this interaction molecular modeling of the N-terminal region of fibroin with Ca(2+) ions was performed. Negatively charged glutamate and aspartate amino acids play a key role in the electrostatic interaction with positively charged calcium ions. Therefore, insights about modulation of self-assembly mechanism of fibroin could potentially be utilized to develop silk-based biomaterials consisting of the desired secondary conformation.

A facile and green ultrasonic-assisted synthesis of BSA conjugated silver nanoparticles.

The formation and growth of hybrid nanoparticles of a protein BSA and silver by ultrasonic assistance were tracked by surface plasmon resonance signal of silver nanoparticles and light scattering. The hybrid nanoparticles were characterized by surface plasmon resonance spectra, light scattering, TEM, circular dichroism spectroscopy and zeta potential. Size along with the spherical shape of the nanoparticles could be controlled and nanoparticles with diameters ranging from 8 to 140 nm could be obtained, depending upon the ultrasonication time (15-30 min) and molar ratio of AgNO(3)/BSA (20-200). The role of single free thiol group in the reduction of silver ions was also investigated by using DTNB modified BSA and protein conjugated silver nanoparticles were formed even with thiol modified BSA. The growth and size of the nanoparticles were governed by ultrasonic assisted Ostwald ripening. BSA conjugated with silver nanoparticles showed changes in the secondary structure with an increase in the beta sheet structure to 33% as compared to 7% in native BSA as determined by CD spectra. Zeta potential measurements in the pH range of 2.0-12.0 demonstrated that the surface charges of the BSA conjugated silver nanoparticles were similar to that of native BSA suggesting that surface charges and overall three dimensional structure of BSA did not change much. This approach provides a strategy for completely green synthesis of hybrid nanoparticles consisting of a biological entity and an inorganic material. This is the first application of ultrasonic assistance in formation of such hybrid nanomaterials in aqueous media.

Nucleotide sequencing and identification of some wild mushrooms.

The rDNA-ITS (Ribosomal DNA Internal Transcribed Spacers) fragment of the genomic DNA of 8 wild edible mushrooms (collected from Eastern Chota Nagpur Plateau of West Bengal, India) was amplified using ITS1 (Internal Transcribed Spacers 1) and ITS2 primers and subjected to nucleotide sequence determination for identification of mushrooms as mentioned. The sequences were aligned using ClustalW software program. The aligned sequences revealed identity (homology percentage from GenBank data base) of Amanita hemibapha [CN (Chota Nagpur) 1, % identity 99 (JX844716.1)], Amanita sp. [CN 2, % identity 98 (JX844763.1)], Astraeus hygrometricus [CN 3, % identity 87 (FJ536664.1)], Termitomyces sp. [CN 4, % identity 90 (JF746992.1)], Termitomyces sp. [CN 5, % identity 99 (GU001667.1)], T. microcarpus [CN 6, % identity 82 (EF421077.1)], Termitomyces sp. [CN 7, % identity 76 (JF746993.1)], and Volvariella volvacea [CN 8, % identity 100 (JN086680.1)]. Although out of 8 mushrooms 4 could be identified up to species level, the nucleotide sequences of the rest may be relevant to further characterization. A phylogenetic tree is constructed using Neighbor-Joining method showing interrelationship between/among the mushrooms. The determined nucleotide sequences of the mushrooms may provide additional information enriching GenBank database aiding to molecular taxonomy and facilitating its domestication and characterization for human benefits.

Simultaneous refolding and purification of recombinant proteins by macro-(affinity ligand) facilitated three-phase partitioning.

A strategy called macro-(affinity ligand) facilitated three-phase partitioning (MLFTPP) is described for refolding of a diverse set of recombinant proteins starting from the solubilized inclusion bodies. It essentially consists of: (i) binding of the protein with a suitable smart polymer and (ii) precipitating the polymer-protein complex as an interfacial layer by mixing in a suitable amount of ammonium sulfate and t-butanol. Smart polymers are stimuli-responsive polymers that become insoluble on the application of a suitable stimulus (e.g., a change in the temperature, pH, or concentration of a chemical species such as Ca(2+) or K(+)). The MLFTPP process required approximately 10min, and the refolded proteins were found to be homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The folded proteins were characterized by fluorescence emission spectroscopy, circular dichroism spectroscopy, biological activity, melting temperature, and surface hydrophobicity measurements by 8-anilino-1-naphthalenesulfonate fluorescence. Two refolded antibody fragments were also characterized by measuring K(D) by Biacore by using immobilized HIV-1 gp120. The data demonstrate that MLFTPP is a rapid and convenient procedure for refolding a variety of proteins from inclusion bodies at high concentration. Although establishing the generic nature of the approach would require wider trials by different groups, its success with the diverse kinds of proteins tried so far appears to be promising.

Role of smart polymers in protein purification and refolding.

Affinity precipitation is a non-chromatographic method which is useful for purification and refolding of proteins. Quite often, a stimuli-sensitive polymer can be identified which selectively binds to the desired protein. For separation, the protein can be recovered from the precipitate of the protein-smart polymer complex. In case of a refolding experiment, binding of the solubilized protein (in its denatured form) with the polymer leads to the refolding of the protein.

Smart polymer mediated purification and recovery of active proteins from inclusion bodies.

Obtaining correctly folded proteins from inclusion bodies of recombinant proteins expressed in bacterial hosts requires solubilization with denaturants and a refolding step. Aggregation competes with the second step. Refolding of eight different proteins was carried out by precipitation with smart polymers. These proteins have different molecular weights, different number of disulfide bridges and some of these are known to be highly prone to aggregation. A high throughput refolding screen based upon fluorescence emission maximum around 340 nm (for correctly folded proteins) was developed to identify the suitable smart polymer. The proteins could be dissociated and recovered after the refolding step. The refolding could be scaled up and high refolding yields in the range of 8 mg L(-1) (for CD4D12, the first two domains of human CD4) to 58 mg L(-1) (for malETrx, thioredoxin fused with signal peptide of maltose binding protein) were obtained. Dynamic light scattering (DLS) showed that polymer if chosen correctly acted as a pseudochaperonin and bound to the proteins. It also showed that the time for maximum binding was about 50 min which coincided with the time required for incubation (with the polymer) before precipitation for maximum recovery of folded proteins. The refolded proteins were characterized by fluorescence emission spectra, circular dichroism (CD) spectroscopy, melting temperature (T(m)), and surface hydrophobicity measurement by ANS (8-anilino1-naphthalene sulfonic acid) fluorescence. Biological activity assay for thioredoxin and fluorescence based assay in case of maltose binding protein (MBP) were also carried out to confirm correct refolding.

Non-chromatographic strategies for protein refolding.

Overexpression of recombinant proteins in bacterial systems (such as E. coli) often leads to formation of inactive and insoluble ' inclusion bodies' . Protein refolding refers to folding back the proteins after solubilizing/unfolding the misfolded proteins of the inclusion bodies. Protein aggregation, a concentration dependent phenomenon, competes with refolding pathway. The refolding strategies largely aim at reducing aggregation and/or promoting correct folding. This review focuses on non-chromatographic strategies for refolding like dilution, precipitation, three phase partitioning and macro-(affinity ligand) facilitated three phase partitioning. The nanomaterials which disperse well in aqueous buffers are also discussed in the context of facilitating protein refolding. Apart from general results with these methods, the review also covers the use of non-chromatographic methods in protein refolding in the patented literature beyond 2000. The patented literature generally describes use of cocktail of additives which results in increase in refolding yield. Such additives include low concentration of chaotropic agents, redox systems, ions like SO4(2-) and Cl-, amines, carboxylic acids and surfactants. Some novel approaches like use of a "pressure window" or ionic liquids for refolding and immobilized diselenide compounds for ensuring correct -S-S- bonds pairing have also been discussed in various patents. In most of the patented literature, focus naturally has been on refolding in case of pharmaceutical proteins.