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During the COVID-19 pandemic, many businesses displayed signs to promote preventive behaviors, such as wearing masks in public, but the effectiveness of this practice largely remains unknown. This ...

Internet users experience a variety of online security threats that require them to enact safety precautions. Protection motivation theory (PMT) provides a theoretical framework for understanding Internet users' security protection that has informed past research. Ongoing research on online safety recommends new motivational factors that are integrated here in a PMT framework for the first time. Using PMT, a cross-sectional survey (N?=?988) of Amazon Mechanical Turk (MTurk) users was conducted to examine how classical and new PMT factors predicted security intentions. Coping appraisal variables were the strongest predictors of online safety intentions, especially habit strength, response efficacy, and personal responsibility. Threat severity was also a significant predictor. Incorporating additional factors (i.e., prior experiences, subjective norms, habit strength, perceived security support, and personal responsibility) into the conventional PMT model increased the model's explanatory power by 15%. Findings are discussed in relation to advancing PMT within the context of online security for home computer users.

A putative laccase gene was cloned from Shigella dysenteriae W202 and expressed in Escherichia coli as a soluble fusion protein with high yield. The purified product ( Wlac ) was characterized as the CueO-like laccase from E. coli , a monomer of molecular mass 55 kDa, with a maximum activity of 24.4 U/mg ( K m = 0.086) and a pH optimum of 2.5, in a standard assay using ABTS (2,2′-azino-di(3-ethyl-benzthiazoline-6-sulfonate) as the substrate. Activity was stable at 0–25 °C but inhibited above 40 °C. Purified Wlac was completely inhibited by 200 mM EDTA and partially by 32 mM SDS, 50 mM NaN 3 and 60 mM thioglycolic acid. Activity was stimulated by Cu 2+ ; other metal ions had only slight or negative effects. Two mutated variants, WlacS and WlacD , were obtained by substituting Glu 106 with Phe 106, and adding a deletion of an α-helix domain (from Leu 351 to Gly 378). WlacS had a 2.2-fold (52.9 U/mg) and WlacD a 3.5-fold (85.1 U/mg) higher enzyme activity than the wild-type laccase and WlacD showed greater thermostability at higher temperatures. Sce VMA intein-associated fusion proteins maintained ∼80% of total enzyme activity. Thus, deletion and site-directed mutagenesis of laccases are capable of promoting both enzymatic activity and thermostability.

An improved surface-immobilisation system was engineered to target heterologous proteins onto vegetative cells and spores of Bacillus thuringiensis plasmid-free recipient strain BMB171. The sporulation-dependent spore cortex-lytic enzyme from B. thuringiensis YBT-1520, SceA, was expressed in vegetative cells and used as the surface anchoring motif. Green fluorescent protein (GFP) and a Bacillus endo-β-1,3-1,4-glucanase (BglS) were used as the fusion partners to test the binding efficiency and the functional activities of immobilised surface proteins. The surface localisation of the SceA-GFP fusion protein on vegetative cells and spores was confirmed by Western blot, immunofluorescence microscopy and flow cytometry. The GFP fluorescence intensity from both vegetative cells and spores was measured and compared to a previously characterised surface display system using a peptidoglycan hydrolase anchor (Mbg). Results demonstrated comparable efficiency of SceA- and Mbg-mediated immobilisation on vegetative cells but a more efficient immobilisation on spores using the SceA anchor, suggesting SceA has greater potential for spore-based applications. The SceA protein was then applied to target BglS onto vegetative cells and spores, and the surface immobilisation was verified by the substantial whole-cell enzymatic activity and enhanced whole-spore enzymatic activity compared to vegetative cells. A dually active B. thuringiensis vegetative cell and spore display system could prove especially valuable for the development of regenerable and heat-stable biocatalysts that function under adverse environmental conditions, for example, an effective feed additive for improved digestion and nutrient absorption by livestock.