Proteobacterial Antimicrobial Compound Efflux (PACE) family proteins are one of seven types of multidrug efflux pumps in Gram-negative bacteria. PACE proteins can actively efflux synthetic biocides, including the antiseptic chlorhexidine, whilst their physiological substrates are polyamines. PACE proteins contain four putative transmembrane-spanning alpha-helices, and experimental evidence suggests that they mainly exist and function in a dimeric state, but the high-resolution structural organisation and molecular mechanism of PACE proteins are yet to be elucidated experimentally. As an essential first step to achieve this, we employed a strategy for gene cloning, expression screening and large-scale purification of representative PACE proteins. The genes of 24 proteins were successfully cloned into IPTG-inducible plasmid pTTQ18 directly upstream from a His6-tag coding sequence and transformed into E. coli BL21(DE3) cells. Small-scale expression tests identified seven proteins amplified at a sufficient level for larger-scale cultures and purification. Based on results from 30-litre fermentor cultures and inner membrane preparations, four proteins (A1S_2063, Fbal_3166, STY_3166, Tmarg_opt) representing distinct phylogenetic groups of the PACE family, were progressed to detergent solubilisation and purification. These proteins had purities of 86, 84, 80 and 78%, and purification yields of 1.1, 1.1, 1.3 and 1.0 mg/litre cell culture, respectively. The detergent-solubilised purified proteins had far-UV circular dichroism spectra consistent with alpha-helical secondary structure, producing melting temperatures of 46.7, 34.2, 32.6 and 37.6 C, respectively. A1S_2063 was most stable and might be best for structure elucidation. Secondary structure in all purified proteins appeared reasonably stable for performing biochemical and biophysical experiments up to 25 C.

The trace metal zinc is essential in all types of organisms, where it has many catalytic, structural and regulatory functions. Zinc homeostasis in cells and organelles is maintained by various types of zinc transport protein. These include Cation Diffusion Facilitator (CDF) family proteins, which export zinc to the extracellular space or to the cytoplasm. Homologous CDF proteins are found in both prokaryotes and eukaryotes, where the human variants are the ZnTs or SLC30 family. One of the first and best characterised prokaryotic CDFs is the Escherichia coli zinc exporter ZitB, which is driven by the proton motive force in an antiport manner. In this article we provide an analytical review and expand on the biochemical and computational characterisation of ZitB and assess its potential for high-resolution three-dimensional structure determination. Consistent with structures determined for other CDF proteins (YiiP, ZnTs 3, 4, 7 and 8), the 313 residues of ZitB are predicted to form six transmembrane spanning α-helices with a long cytoplasmic C-terminal tail. An unusual feature of ZitB is an exceptionally high (8.0%) content of histidine residues. Using the IPTG-inducible plasmid pTTQ18, we demonstrate the cloning and amplified expression in E. coli of non-tagged, wild-type ZitB at levels of ~15% of total protein in preparations of inner membranes. ZitB was solubilised in the mild detergent n-dodecyl-β-D-maltoside (DDM) and purified by immobilised metal affinity chromatography in yields of ~1.8 mg per litre of culture medium. The structural integrity of purified ZitB was confirmed by mass spectrometry and circular dichroism spectroscopy.

Tribulus terrestris is a member of the family Zygophyllaceae commonly known as “puncture vine”. The plant has been used traditionally as an analgesic and to relieve rheumatic pain, eye problems, sexual dysfunction and edema. The aim of this work was to test the use of T. terrestris fruit extract as a reducing agent in synthesizing gold nanoparticles (AuNPs), test their biological activities, and assess their suitability as a therapeutic agent by testing them for potential adverse effects on human cells. Indeed, we have performed the most comprehensive biological testing of AuNPs produced using T. terrestris extracts to date. The aqueous extract of dried powdered T. terrestris fruits was used for the reduction of hydrogen tetrachloroaurate (III) trihydrate (AuCl4·3H2O). The fruit extract's phytochemical components effectively served as reducing, capping and stabilizing agents, resulting in the production of consistent and round-shaped AuNPs with a size range of less than 100 nm. The synthesized AuNPs were subjected to various physicochemical analyses, then evaluated for antibacterial, antifungal and antileishmanial activity, and subjected to hemagglutination, cytotoxicity and antioxidant bioassays. The AuNPs showed inhibition zones against several bacterial and fungal strains, and exhibited antileishmanial activity at high doses. The AuNPs demonstrated positive hemagglutination activity against human Red Blood Cells (RBCs) of blood groups A and B at 10 and 20 µg/mL, but no hemagglutination activity against groups AB and O at up to 40 µg/mL. The AuNPs showed no cytotoxicity against human RBCs at up to 40 µg/mL, suggesting that they may be suitable for use in a clinical setting. The antioxidant activity of the AuNPs was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and the results indicated a high antioxidant potential.

Microscale thermophoresis (MST) is an analytical technique for measuring biomolecular interactions. It is based on the physical phenomenon that particles move within temperature gradients, which is affected by their size, charge, hydration shell and conformation. The MST sample must contain a fluorescent target molecule used to observe the movement of particles, and this can be titrated with an unlabelled binding partner for quantifying the interaction. MST is highly sensitive, using relatively small amounts of sample, and it has no limitations on the size of the target biomolecule, on the affinity of the interaction or on the composition of the buffer and other sample components. This makes MST ideally suited to characterising interactions with membrane proteins, which can be studied in cell lysates, native membranes, solubilised in detergents or reconstituted in lipids. The intrinsic aromatic residues of membrane proteins have been used as the fluorophore for MST (label-free MST) or membrane proteins have been labelled with a range of fluorescent dyes or conjugated with fluorescent proteins (labelled MST). The different types of membrane proteins that have had biomolecular interactions characterised by MST include the SARS-CoV-2 spike protein, GPCRs and other receptors, sensor kinases, ion channels, aquaporins, and transport proteins.

The nucleoside transporter NupG is one of the two principal transport proteins in the inner membrane of Escherichia coli that enable the organism to scavenge nucleosides from its external environment. NupG functions in a symport manner driven by the proton motive force and is a member of the Nucleoside:H+ Symporter (NHS) subfamily of the Major Facilitator Superfamily (MFS) of transporters. NupG has broad substrate specificity, transporting all naturally occurring purine and pyrimidine nucleosides. In studies over many years the nupG gene has been cloned and amplified, and the NupG protein has been purified, subjected to biochemical, biophysical and computational analysis, and its X-ray structure determined in the apo state at 3.0 Å resolution. The NupG structure had a typical MFS fold with twelve transmembrane spanning α-helices and distinct N- and C-terminal domains linked by a flexible loop. Preliminary site-directed mutagenesis and molecular docking studies on NupG identified nine putative nucleoside binding pocket residues (R136, T140, F143, Q225, N228, Q261, E264, Y318, F322) and a mutant (D323A) with 20-fold enhanced uridine binding activity. Further biochemical and structural investigations are necessary to better understand the substrate recognition and molecular mechanism of E. coli NHS family proteins (NupG, XapB, YegT).

Nuclear magnetic resonance (NMR) spectroscopy is a powerful non-invasive analytical technique with wide applications that can observe multiple nuclear species at a site-resolved level. Despite this, NMR has inherent low sensitivity compared to other analytical techniques. A principal approach to improve the sensitivity and resolution of the NMR experiment is to increase the strength of the external static magnetic field (B0), for which the upper practicable limit has gradually increased over five decades. The relatively recent use of high-temperature superconducting materials, such as Bi2Sr2Ca2Cu3Ox (Bi-2223), Bi2Sr2CaCu2Ox (Bi-2212) or REBa2Cu3O7-x (REBCO, RE = rare earth), has enabled construction of ultra-high field NMR magnets. Over twenty commercial ultra-high field NMR instruments at 1.0, 1.1 and 1.2 GHz (23.5, 25.9 and 28.2 Tesla, respectively) have been installed worldwide in the past several years, with more to come. NMR at ultra-high fields benefits both solution-state and solid-state NMR applications. The potential improvements in sensitivity and resolution in NMR spectra are particularly important for studying the structure, dynamics and ligand interactions of biomolecules, which can suffer from poor sensitivity and prohibitive signal crowding. The benefits of using ultra-high field NMR have begun to be demonstrated on various sample types, including intrinsically disordered proteins, membrane proteins, amyloid fibrils, viral capsids, bacterial chlorosomes, fungal cell walls, and whole human cells. Alongside optimisations in sample preparation, probe design and pulse sequences, and exploitation of dynamic nuclear polarisation (DNP), ultra-high field magnets are contributing to an exciting period for improving the sensitivity and resolution of NMR spectra in the study of more complex biomolecules and other samples.

The present study primarily focuses on "Polarising Agents and Spin Tags for Dynamic Nuclear Polarisation (DNP)-Enhanced Solid-State Nuclear Magnetic Resonance (ssNMR) Analysis of Biological Samples". For biological materials that are frozen or have a solid-like consistency, ssNMR spectroscopy can provide structural, functional, and ligand-binding information. ssNMR spectra can be greatly improved with the application of dynamic nuclear polarisation (DNP). Through microwave irradiation at or near the electron Larmor frequency, polarisation transfer from high-gyromagnetic ratio (Y) unpaired electrons to neighboring nuclei occurs in DNP. This produces an absolute increase in the signal-to-noise ratio and allows experiments on much smaller quantities of sample and/or using much shorter acquisition times. Along with necessary instrumentation an essential requirement for DNP-ssNMR is a sample with an endogenous free radical or an exogenous free radical polarising agent must be added to the sample. The polarising agent must be soluble in the sample matrix and compatible with the biological sample. The free radical(s) of the polarising agent also must be stable for the lifetime of DNP-ssNMR experiments. Nitroxides have been most used as polarising agents, including the biradical compounds TOTAPOL and AMUPol with a wide range of biological samples to produce DNP enhancement factors (\(\varepsilon\)) of up to 250. Derivatives of TOTAPOL and AMUPol and many other different polarising agents have also been used. Whilst conventional polarising agents are mixed throughout the sample, others are targeted at specific sites to provide a more localised signal enhancement. Here we review the different polarising agents and spin tags that have been used in DNP-ssNMR studies on biological samples. Targeted polarising agents enable use of matrix-free samples to concentrate the sample, whilst others can be covalently bound to provide signal enhancement at highly specific sites. The continued development of novel polarising agents and labelling and sample preparation strategies for DNP-ssNMR can open many biological samples to NMR studies that were not previously possible.

AbstractMembers of the concentrative nucleoside transporter (CNT) family of proteins mediate uptake of nucleosides into cells driven by a cation gradient, which then enter salvage pathways for nucleic acid synthesis. In humans, they also transport hydrophilic anticancer and antiviral nucleoside analogue drugs into cells and tissues where they exert their pharmacological effects.Escherichia coliCNT NupC (400 residues) is pyrimidine-specific and driven by a proton gradient. We have used computational, biochemical, and biophysical methods to characterize evolutionary relationships, conservation of residues, structural domains, transmembrane helices, and residues involved in nucleoside binding and/or transport activity in NupC compared with those of sodium-drivenVibrio cholerae CNT (vcCNT) and human CNTs (hCNT1−3). As in the crystal structure of vcCNT, NupC appears to contain eight transmembrane-spanning α-helices. Wild-type NupC and single-cysteine-containing mutants were tested for transport activity in energizedE. coliwhole cells and for binding of nucleosides in non-energized native inner membranes using novel cross-polarization magic-angle spinning solid-state nuclear magnetic resonance methods. Wild-type NupC had an apparent affinity of initial rate transport (Kmapp) for [14C]uridine of 22.2 ± 3.7μM and an apparent binding affinity (Kdapp) for [1′-13C]uridine of 1.8−2.6 mM. Mutant S142C retained transport and binding affinities similar to those of the wild type. Mutants G146C and E149C had no transport activity but retained varying degrees of partial binding activity with affinities decreasing in the following order: wild type > S142C > G146C > E149C. Results were explained with respect to a homology model of NupC based on the structure of vcCNT and a hypothetical elevator-type mechanism of alternating access membrane transport in NupC.

Members of the concentrative nucleoside transporter (CNT) family of proteins mediate uptake of nucleosides into cells driven by a cation gradient, which then enter salvage pathways for nucleic acid synthesis. In humans, they also transport hydrophilic anticancer and antiviral nucleoside analogue drugs into cells and tissues where they exert their pharmacological effects. Escherichia coli CNT NupC (400 residues) is pyrimidine-specific and driven by a proton gradient. We have used computational, biochemical, and biophysical methods to characterize evolutionary relationships, conservation of residues, structural domains, transmembrane helices, and residues involved in nucleoside binding and/or transport activity in NupC compared with those of sodium-driven Vibrio cholera e CNT (vcCNT) and human CNTs (hCNT1−3). As in the crystal structure of vcCNT, NupC appears to contain eight transmembrane-spanning α-helices. Wild-type NupC and single-cysteine-containing mutants were tested for transport activity in energized E. coli whole cells and for binding of nucleosides in non-energized native inner membranes using novel cross-polarization magic-angle spinning solid-state nuclear magnetic resonance methods. Wild-type NupC had an apparent affinity of initial rate transport ( K mapp) for [14C]uridine of 22.2 ± 3.7 μ M and an apparent binding affinity ( K dapp) for [1′-13C]uridine of 1.8−2.6 mM. Mutant S142C retained transport and binding affinities similar to those of the wild type. Mutants G146C and E149C had no transport activity but retained varying degrees of partial binding activity with affinities decreasing in the following order: wild type > S142C > G146C > E149C. Results were explained with respect to a homology model of NupC based on the structure of vcCNT and a hypothetical elevator-type mechanism of alternating access membrane transport in NupC.### Competing Interest StatementThe authors have declared no competing interest.

Solid-state nuclear magnetic resonance (ssNMR) spectroscopy can obtain structural, functional and ligand-binding information about frozen and solid-like biological samples. ssNMR spectra can be enhanced by orders of magnitude using the technique of dynamic nuclear polarisation (DNP). In DNP there is polarisation transfer from high-gyromagnetic ratio (γ) unpaired electrons to neighbouring nuclei using microwave irradiation at or near the electron Larmor frequency. This produces an absolute increase in the signal-to-noise ratio and allows experiments on much smaller quantities of sample and/or using much shorter acquisition times. Along with necessary instrumentation an essential requirement for DNP-ssNMR is a sample with an endogenous free radical or an exogenous free radical polarising agent must be added to the sample. The polarising agent must be soluble in the sample matrix and compatible with the biological sample. The free radical(s) of the polarising agent also must be stable for the lifetime of DNP-ssNMR experiments. Nitroxides have been most used as polarising agents, including the biradical compounds TOTAPOL and AMUPol with a wide range of biological samples to produce DNP enhancement factors (e) of up to 250. Derivatives of TOTAPOL and AMUPol and many other different polarising agents have also been used. Whilst conventional polarising agents are mixed throughout the sample, others are targeted at specific sites to provide a more localised signal enhancement. Here we review the different polarising agents and spin tags that have been used in DNP-ssNMR studies on biological samples.

The aim of this work was to test polyamines as potential natural substrates of the Acinetobacter baumannii chlorhexidine efflux protein AceI using near-UV synchrotron radiation circular dichroism (SRCD) spectroscopy. The Gram-negative bacterium A. Baumannii is a leading cause of hospital-acquired infections and an important foodborne pathogen. A. Baumannii strains are becoming increasingly resistant to antimicrobial agents, including the synthetic antiseptic chlorhexidine. AceI (144-residues) was the founding member of the recently recognised PACE family of bacterial multidrug efflux proteins. Using the plasmid construct pTTQ18-aceI(His6) containing the A. baumannii aceI gene directly upstream from a His6-tag coding sequence, expression of AceI(His6) was amplified in E. coli BL21(DE3) cells. Near-UV (250–340 nm) SRCD measurements were performed on detergent-solubilised and purified AceI(His6) at 20 °C. Sample and SRCD experimental conditions were identified that detected binding of the triamine spermidine to AceI(His6). In a titration with spermidine (0–10 mM), this binding was saturable and fitting of the curve for the change in signal intensity produced an apparent binding affinity (KD) of 3.97 ± 0.45 mM. These SRCD results were the first experimental evidence obtained for polyamines as natural substrates of PACE proteins.

Despite ongoing vaccination programs against COVID-19 around the world, cases of infection are still rising with new variants. This infers that an effective antiviral drug against COVID-19 is crucial along with vaccinations to decrease cases. A potential target of such antivirals could be the membrane components of the causative pathogen, SARS-CoV-2, for instance spike (S) protein. In our research, we have deployed in vitro screening of crude extracts of seven ethnomedicinal plants against the spike receptor-binding domain (S1-RBD) of SARS-CoV-2 using an enzyme-linked immunosorbent assay (ELISA). Following encouraging in vitro results for Tinospora cordifolia, in silico studies were conducted for the 14 reported antiviral secondary metabolites isolated from T. cordifolia-a species widely cultivated and used as an antiviral drug in the Himalayan country of Nepal-using Genetic Optimization for Ligand Docking (GOLD), Molecular Operating Environment (MOE), and BIOVIA Discovery Studio. The molecular docking and binding energy study revealed that cordifolioside-A had a higher binding affinity and was the most effective in binding to the competitive site of the spike protein. Molecular dynamics (MD) simulation studies using GROMACS 5.4.1 further assayed the interaction between the potent compound and binding sites of the spike protein. It revealed that cordifolioside-A demonstrated better binding affinity and stability, and resulted in a conformational change in S1-RBD, hence hindering the activities of the protein. In addition, ADMET analysis of the secondary metabolites from T. cordifolia revealed promising pharmacokinetic properties. Our study thus recommends that certain secondary metabolites of T. cordifolia are possible medicinal candidates against SARS-CoV-2.

A biofilm is a community of stable microorganisms encapsulated in an extracellular matrix produced by themselves. Many types of microorganisms that are found on living hosts or in the environment can form biofilms. These include pathogenic bacteria that can serve as a reservoir for persistent infections, and are culpable for leading to a broad spectrum of chronic illnesses and emergence of antibiotic resistance making them difficult to be treated. The absence of biofilm-targeting antibiotics in the drug discovery pipeline indicates an unmet opportunity for designing new biofilm inhibitors as antimicrobial agents using various strategies and targeting distinct stages of biofilm formation. The strategies available to control biofilm formation include targeting the enzymes and proteins specific to the microorganism and those involved in the adhesion pathways leading to formation of resistant biofilms. This review primarily focuses on the recent strategies and advances responsible for identifying a myriad of antibiofilm agents and their mechanism of biofilm inhibition, including extracellular polymeric substance synthesis inhibitors, adhesion inhibitors, quorum sensing inhibitors, efflux pump inhibitors, and cyclic diguanylate inhibitors. Furthermore, we present the structure–activity relationships (SAR) of these agents, including recently discovered biofilm inhibitors, nature-derived bioactive scaffolds, synthetic small molecules, antimicrobial peptides, bioactive compounds isolated from fungi, non-proteinogenic amino acids and antibiotics. We hope to fuel interest and focus research efforts on the development of agents targeting the uniquely complex, physical and chemical heterogeneous biofilms through a multipronged approach and combinatorial therapeutics for a more effective control and management of biofilms across diseases.

The agent responsible for the COVID-19 pandemic was the newly discovered coronavirus SARS-CoV-2. A trimeric spike protein on the SARS-CoV-2 virion binds to the ACE2 receptor on host cells. In this study we performed a structure-based virtual screening and molecular docking of existing drugs against a high-resolution structure of the SARS-CoV-2 spike protein-ACE2 receptor complex. The 2.5-Å crystal structure of the C-terminal domain of the SARS-CoV-2 spike protein (residues 319-541) in complex with human ACE2 (SARS-CoV-2-S-CTD/hACE2) (PDB ID: 6LZG) was used as the target for screening 4,374 FDA-approved drugs from the ZINC15 database using PyRx software. Molecular docking was performed using BIOVIA Discovery Studio Visualizer. The top twenty highest affinity drugs had binding energies of -7.0 to -8.8 kcal/mol. The highest affinity drug was the selective vasopressin V2-receptor antagonist Tolvaptan, for which molecular docking identified drug-amino acid residue interactions with ACE2. Other drugs displaying binding energies better than -8.0 kcal/mol were Nizoral, Amaryl, Accolate, Sorafenib, Glipizide and Azelastine. The predicted interactions of these highest affinity drugs with residues in ACE2 were at positions that could disrupt the spike protein-ACE2 complex, so these drugs have the potential to be repurposed as inhibitors of the SARS-CoV-2 virus.

The Rhodococcus erythropolis gene DYC18_RS18060 (1437 bp) putatively codes for a secondary transporter of the Nucleobase Cation Symporter-1 (NCS-1) protein family (478 amino acids). The DYC18_RS18060 gene was successfully cloned from R. erythropolis genomic DNA with addition of EcoRI and PstI restriction sites at the 5′ and 3′ ends, respectively, using PCR technology. The amplified gene was introduced into IPTG-inducible plasmid pTTQ18 immediately upstream of the sequence coding for a His6-tag. The construct was transformed into Escherichia coli BL21(DE3), then amplified expression of the DYC18_RS18060-His6 protein was achieved with detection by SDS-PAGE and western blotting. Computational methods predicted that DYC18_RS18060 has a molecular weight of 51.1 kDa and isoelectric point of 6.58. The protein was predicted to be hydrophobic in nature (aliphatic index 113.24, grand average of hydropathicity 0.728) and to form twelve transmembrane spanning α-helices with both N- and C-terminal ends at the cytoplasmic side of the membrane. Whilst database sequence similarity searches and phylogenetic analysis suggested that the substrate of DYC18_RS18060 could be cytosine, this was not certain based on comparisons of residues involved in substrate binding in experimentally characterised NCS-1 proteins. This study has laid foundations for further structural and functional studies of DYC18_RS18060 and other NCS-1 proteins. Copyright(c) The Authors

This study analyzed raw (unpasteurized) dairy milk samples from farms, milk vendors, and shops in the Peshawar region of Pakistan for the prevalence of pathogenic multidrug-resistant (MDR) Escherichia coli. During August 2018-September 2019, 100 cow ' s milk samples from 10 subregions of the Town-3 district were tested for the prevalence of E. coli and of Shiga toxin-producing serotype O157: H7 using various biochemical, morphological, and molecular tests. MDR was tested using the disc diffusion method, while Shiga toxin and antibiotic resistance genes were identified by polymerase chain reaction. Twenty eight samples contained E. coli, of which six were positive for O157: H7. The O157: H7 isolates had resistances of 16.7% to amoxicillin-clavulanic acid, 66.7% to ampicillin, 66.7% to ceftriaxone, 50.0% to kanamycin, 83.3% to streptomycin, 83.3% to trimethoprim sulfamethoxazole, and 83.3% to vancomycin. All O157: H7 isolates contained the bla(CTXM) resistance gene, three of which also contained the bla(TEM1) and bla(NDM1) resistance genes, and were resistant to six or seven out of the seven antibiotics tested in a disc diffusion assay with 10 mu g or 30 mu g of antibiotic. Our observations are of high concern to public health in Pakistan, so appropriate measures should be implemented to minimize E. coli O157: H7 cross-contamination and infection, including screening for E. coli O157: H7 in foods, equipment, and storage vessels; testing of isolates for antibiotic resistance; implementation of rigorous hygiene protocols in milk production and storage; training of farmers and milk production workers; and education of the public about hygiene and food practices.

Abstract The COVID‐19 pandemic has introduced a new battle in human history for a safe and fearless life. Therefore, this cross‐sectional survey was conducted (Punjab, Pakistan) on healthy recovered, home quarantined COVID‐19 patients to draw conclusive health support guidelines in the fight against this pandemic. COVID‐19 recovered patients (n = 80) of age ≥14 years were randomly selected during the period November 2020 to February 2021. A nutrition and lifestyle changes questionnaire, containing ten sections and seventy questions, was completed through the telephone/WhatsApp. Data were transferred into an Excel spreadsheet and statistically analyzed by applying chi‐square, correlation, and a t test of independent values using SPSS‐16 software. The patients had an age range of 14 to 80 years, of which 52 (65%) were male and 28 (35%) were female, and 32 (40%) had a normal BMI. The patients had a peak COVID‐19 recovery period of 2 weeks, and a mean recovery period of 2.8 ± 1.4 weeks. Certain variables, including gender (males), age (>40 years), sleep (≤5 hr), less/no physical activity, obesity, diabetes mellitus, and autoimmune diseases, were significantly associated with delayed recovery. Poor nutritional outcomes, including lower intakes of water, legumes, nuts, meat, and milk/yogurt; and higher consumption of fast/fried/junk/spicy foods and cold water/drinks, were also significantly associated with a longer recovery period. The results were similar for not taking daily doses of multivitamins, and vitamins C, D, E, and zinc. This study identified that staying physically active, maintaining sensible body weight, having a sleep of 7 hr, consuming more foods of plant origin especially plant‐based proteins from nuts and legumes, taking supplemental doses of multivitamins, vitamin D, E, and zinc, along with drinking ≥2 L of water daily can provide a significant role in early and safe recovery from COVID‐19.

Nickel(II) complexes of the following Schiff base ligands derived from 4-(dimethylamino)benzaldehyde were synthesised: (Z)-1-(4-(dimethylamino)benzylideneamino)-propan-1-ol through condensation with 1-amino-propan-1-ol, ((NE)-E-1,(NE)-E-2)-N-1,N-2-bis(4-dimethylamino)benzylidene)benzene-1,2-diamine through condensation with benzene-1,2-diamine and 2-((4-dimethylamino)benzylidene)amino)phenol through condensation with 2-aminophenol. The synthesised Schiff bases and the resultant Ni(II) complexes were all isolated as crystals and characterized by melting point, elemental analysis, infrared spectroscopy, NMR spectroscopy, mass spectrometry and by conductance measurements. Antioxidant activity of the Ni(II) complexes was tested by assay with the free radical compound 2,2-diphenyl-1-picrylhydrazyl (DPPH).