Optimization of Piper betle L. extraction under ultrasound and its effects on chitosan/polyvinyl alcohol film properties for wound dressing.

This study aimed to prepare Piper betle L. extract-load chitosan/polyvinyl alcohol (CS/PVA) film potential for wound dressing and investigate the effects of PLE and PLE-loading methods on physicochemical and biological properties of CS/PVA films. First, Piper betle L.

Investigation on cost-effective composites for CO adsorption from post-gasification residue and metal organic framework.

Cost-effective CO adsorbents are gaining increasing attention as viable solutions for mitigating climate change. In this study, composites were synthesized by electrochemically combining the post-gasification residue of Macadamia nut shell with copper benzene-1,3,5-tricarboxylate (CuBTC). Among the different composites synthesized, the ratio of 1:1 between biochar and CuBTC (B 1:1) demonstrated the highest CO adsorption capacity.

Effects of montmorillonite on the loading and release of Piper betle L. extract applied for wound dressing based on chitosan/polyvinyl alcohol.

In this study, we investigate the influence of montmorillonite (MMT) on the loading and release of Piper betle L. extract (PLE)-a medicinal herb containing active secondary metabolites with antibacterial, antioxidant, and anti-inflammatory effects. MMT (1 %, 3 %, 5 %) was blended into the chitosan/polyvinyl alcohol (CS/PVA) biocomposite film by the solution evaporation method, and then PLE was loaded onto this biocomposite using the immersion method.

Removal of Cu (II) by calcinated electroplating sludge.

Electroplating sludge consists of various heavy metal oxides, which may be utilized as adsorbent to remove Cu (II) present in aqueous environment. This study evaluated the adsorption performance of calcinated electroplating sludge. The adsorption isotherm based on Langmuir equation proved that calcinated electroplating sludge had a higher adsorption performance than raw electroplating sludge, with maximum adsorption capacity 92 mg/g and 76.

A conserved lysine residue controls iron-sulfur cluster redox chemistry in Escherichia coli fumarate reductase.

The Escherichia coli respiratory complex II paralogs succinate dehydrogenase (SdhCDAB) and fumarate reductase (FrdABCD) catalyze interconversion of succinate and fumarate coupled to quinone reduction or oxidation, respectively. Based on structural comparison of the two enzymes, equivalent residues at the interface between the highly homologous soluble domains and the divergent membrane anchor domains were targeted for study. This included the residue pair SdhB-R205 and FrdB-S203, as well as the conserved SdhB-K230 and FrdB-K228 pair.

Out of plane distortions of the heme b of Escherichia coli succinate dehydrogenase.

The role of the heme b in Escherichia coli succinate dehydrogenase is highly ambiguous and its role in catalysis is questionable. To examine whether heme reduction is an essential step of the catalytic mechanism, we generated a series of site-directed mutations around the heme binding pocket, creating a library of variants with a stepwise decrease in the midpoint potential of the heme from the wild-type value of +20 mV down to -80 mV. This difference in midpoint potential is enough to alter the reactivity of the heme towards succinate and thus its redox state under turnover conditions.

Type IV pilin is glycosylated in Pseudomonas syringae pv. tabaci 6605 and is required for surface motility and virulence.

Type IV pilin (PilA) is a major constituent of pilus and is required for bacterial biofilm formation, surface motility and virulence. It is known that mature PilA is produced by cleavage of the short leader sequence of the pilin precursor, followed by methylation of N-terminal phenylalanine. The molecular mass of the PilA mature protein from the tobacco bacterial pathogen Pseudomonas syringae pv.

Escherichia coli succinate dehydrogenase variant lacking the heme b.

The Escherichia coli enzyme succinate:ubiquinone oxidoreductase [(succinate dehydrogenase (SdhCDAB)] couples succinate oxidation to ubiquinone reduction and is structurally and functionally equivalent to mitochondrial complex II, an essential component of the aerobic respiratory chain and tricarboxylic acid cycle. All such enzymes contain a heme within their membrane anchor domain with a highly contentious, but as-yet-undetermined, function. Here, we report the generation of a complex II that lacks heme, which is confirmed by both optical and EPR spectroscopy.

The quinone binding site in Escherichia coli succinate dehydrogenase is required for electron transfer to the heme b.

We have examined the role of the quinone-binding (Q(P)) site of Escherichia coli succinate:ubiquinone oxidoreductase (succinate dehydrogenase) in heme reduction and reoxidation during enzyme turnover. The SdhCDAB electron transfer pathway leads from a cytosolically localized flavin adenine dinucleotide cofactor to a Q(P) site located within the membrane-intrinsic domain of the enzyme. The Q(P) site is sandwiched between the [3Fe-4S] cluster of the SdhB subunit and the heme b(556) that is coordinated by His residues from the SdhC and SdhD subunits.