The SARS-CoV2 envelope differs from host cells,exposes procoagulant lipids,and is disrupted in vivo by oral rinses

The lipid envelope of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an essential component of the virus; however, its molecular composition is undetermined. Addressing this knowledge gap could support the design of antiviral agents as well as further our understanding of viral-host protein interactions, infectivity, pathogenicity, and innate immune system clearance. Lipidomics revealed that the virus envelope comprised mainly phospholipids (PLs), with some cholesterol and sphingolipids, and with cholesterol/phospholipid ratio similar to lysosomes. Unlike cellular membranes, procoagulant amino-PLs were present on the external side of the viral envelope at levels exceeding those on activated platelets. Accordingly, virions directly promoted blood coagulation. To investigate whether these differences could enable selective targeting of the viral envelope in vivo, we tested whether oral rinses containing lipid-disrupting chemicals could reduce infectivity. Products containing PL-disrupting surfactants (such as cetylpyridinium chloride) met European virucidal standards in vitro; however, components that altered the critical micelle concentration reduced efficacy, and products containing essential oils, povidone-iodine, or chlorhexidine were ineffective. This result was recapitulated in vivo, where a 30-s oral rinse with cetylpyridinium chloride mouthwash eliminated live virus in the oral cavity of patients with coronavirus disease 19 for at least 1 h, whereas povidone-iodine and saline mouthwashes were ineffective. We conclude that the SARS-CoV-2 lipid envelope i) is distinct from the host plasma membrane, which may enable design of selective antiviral approaches; ii) contains exposed phosphatidylethanolamine and phosphatidylserine, which may influence thrombosis, pathogenicity, and inflammation; and iii) can be selectively targeted in vivo by specific oral rinses.     

Spectroscopic evidence on the interaction of prephenate, a shikimate pathway intermediate, with oxidovanadium(IV) species

The interaction of the oxidovanadium(IV) cation with the sodium salt of prephenic acid was investigated by electron absorption and electronic paramagnetic resonance spectroscopies in aqueous solution at different pH values. The study allows to demonstrate once more the effectiveness of oxidovanadium(IV) to interact with carboxylate groups. The most probable binding modes of the solution complexes were determined by EPR method. Two main coordination environments around the metal center were established: one includes four-carboxylate moieties and the other the set probably involves alkoxide and hydroxide groups.     

Superoxide dismutase activity and electrochemical study of the binuclear [Cu(TSA)2py]2 complex

The superoxide dismutase-mimetic activity and the electrochemical behavior of the binuclear complex [Cu(TSA)₂py]₂ is reported. The complex exhibits a marked SOD activity in the nitroblue tetrazolium assay. Its redox response is in agrement with two copper atoms partially coupled through the carboxylate moieties. The electrode reactions lie in the range of the superoxide/peroxide and oxygen/superoxide couples. This fact is indicative that this complex can act as catalyst for the SOD reaction.     

A spectrophotometric study of the VO2+-glutathione interactions

The interaction of the vanadyl (IV) cation with reduced glutathione (GSH) has been investigated by electronic absorption spectroscopy, at different metal-to-ligand ratios and pH values. The interaction depends strongly on the initial VO2+/GSH ratio. Starting with a tenfold GSH excess, coordination takes place through the two carboxylate groups of the ligand, generating (at pH = 7) a blue 1:2 VO2+/GSH complex; this stoichiometry could be confirmed by photometric titration experiments. Higher GSH concentrations produce a violet complex, which can also be obtained by addition of GSH to the blue species. Some measurements with the three component amino acids of GSH, as well as results obtained from the VO3-/GSH system, allowed a wider insight into the characteristics of this violet complex, in which the cation interacts with S and N atoms of the peptide.     

The Physico-Chemical Properties of Dietary Fibre Determine Metabolic Responses,Short-Chain Fatty Acid Profiles and Gut Microbiota Composition in Rats Fed Low- and High-Fat Diets

The aim of this study was to investigate how physico-chemical properties of two dietary fibres, guar gum and pectin, affected weight gain, adiposity, lipid metabolism, short-chain fatty acid (SCFA) profiles and the gut microbiota in male Wistar rats fed either low- or high-fat diets for three weeks. Both pectin and guar gum reduced weight gain, adiposity, liver fat and blood glucose levels in rats fed a high-fat diet. Methoxylation degree of pectin (low, LM and high (HM)) and viscosity of guar gum (low, medium or high) resulted in different effects in the rats, where total blood and caecal amounts of SCFA were increased with guar gum (all viscosities) and with high methoxylated (HM) pectin. However, only guar gum with medium and high viscosity increased the levels of butyric acid in caecum and blood. Both pectin and guar gum reduced cholesterol, liver steatosis and blood glucose levels, but to varying extent depending on the degree of methoxylation and viscosity of the fibres. The medium viscosity guar gum was the most effective preparation for prevention of diet-induced hyperlipidaemia and liver steatosis. Caecal abundance of Akkermansia was increased with high-fat feeding and with HM pectin and guar gum of all viscosities tested. Moreover, guar gum had distinct bifidogenic effects independent of viscosity, increasing the caecal abundance of Bifidobacterium ten-fold. In conclusion, by tailoring the viscosity and possibly also the degree of methoxylation of dietary fibre, metabolic effects may be optimized, through a targeted modulation of the gut microbiota and its metabolites.     

Tail regenerative capacity and iNOS immunolocalization in <Emphasis Type="Italic">Xenopus laevis</Emphasis> tadpoles

The morphology and the immuno-distribution of the inducible isoform of nitric oxide synthase (iNOS) have been examined in regenerating tails from differently aged Xenopus laevis larvae. By comparing stage-50 and stage-55/56 tadpoles, various morphological aspects and immunoreactivity to anti-iNOS antibody in terms of the number and duration of positive cells have been demonstrated in the regenerating buds. Unlike in stage-50 larvae, the extent of responses to tail amputation in older larvae is more dependent on the individual tadpole and a high percentage (70%-80%) of malformed tails has been seen. The findings indicate that the decline in the efficiency of Xenopus tail regeneration is driven by differences in the inflammatory responses and in the involvement of nitric oxide. This molecule is induced and required for normal tail regeneration, whereas in excess, it is probably associated with progressive loss in the regeneration capability.     

Histidine affinity tags affect MSP1(42) structural stability and immunodominance in mice

Inclusion of affinity tags has greatly facilitated process development for protein antigens, primarily for their recovery from complex mixtures. Although generally viewed as supportive of product development, affinity tags may have unintended consequences on protein solubility, susceptibility to aggregation, and immunogenicity. Merozoite surface protein 1 (MSP1), an erythrocytic stage protein of Plasmodium falciparum and a candidate malaria vaccine, was used to evaluate the impact of a metal ion affinity-tag on both protein structure and the induction of immunity. To this end, codon harmonized gene sequences from the P. falciparum MSP1(42) of FVO and 3D7 parasites were cloned and purified with and without a histidine (His) tag. We report on the influence of His-affinity tags on protein expression levels, solubility, secondary structure, thermal denaturation, aggregation and the impact on humoral and cellular immune responses in mice. While the overall immunogenicity induced by His-tagged MSP1(42) proteins is greater, the fine specificity of the humoral and cellular immune responses is altered relative to anti-parasitic antibody activity and the breadth of T-cell responses. Thus, the usefulness of protein tags may be outweighed by their potential impact on structure and function, stressing the need for caution in their use. See accompanying commentary by Randolph DOI: 10.1002/biot.201100459.