Tailor-made magnetic nanocomposite with pH and thermo-dual responsive copolymer brush for bacterial separation.

Rapid detection of pathogenic bacteria particularly in food samples demands efficient separation and enrichment strategies. Here, hydrophilic temperature-responsive boronate affinity magnetic nanocomposites were established for selective enrichment of bacteria. The thermo-responsive polymer brushes were developed by surface-initiated atom transfer radical polymerization of N-isopropylacrylamide (NIPAm) and allyl glycidyl ether (AGE), followed by a reaction of epoxy groups, and incorporation of fluorophenylboronic acid. The physical and chemical characteristics of the magnetic nanocomposites were analyzed systematically. After optimization, S. aureus and Salmonella spp. showed high binding capacities of 32.14 × 106 CFU/mg and 50.98 × 106 CFU/mg in 0.01 M PBS (pH 7.4) without bacteria death. Bacterial bindings can be controlled by altering temperature and the application of competing monosaccharides. The nanocomposite was then utilized to enrich S. aureus and Salmonella spp. from the spiked tap water, 25% milk, and turbot extraction samples followed by multiplex polymerase chain reaction (mPCR), which resulted in high bacteria enrichment, and demonstrated great potential in separation of bacteria from food samples.

Extraction, Identification, Modification, and Antibacterial Activity of Histone from Immature Testis of Atlantic salmon.

In the present study, histone from immature testis of Atlantic salmon was extracted and identified, and its antibacterial activity after enzymolysis was investigated. Histone extracted from Atlantic salmon (Salmo salar) testis using the acid extraction method was successfully identified by LC-MS/MS, and revealed significant inhibitory activity on both the Gram-negative and Gram-positive bacteria. With a low concentration of 10 mg/mL, the observed inhibitory zone diameter (IZD) could significantly reach up to 15.23 mm. After modification of enzymatic hydrolysis by pepsin, histone could be digested to three fragments, while the antibacterial activity increased up to 57.7%. All the results suggested the leftovers from commercial fishing could be utilized for the extraction of antimicrobial peptides.

Effect of laccase-catalyzed cross-linking on the structure and allergenicity of Paralichthys olivaceus parvalbumin mediated by propyl gallate.

The aim of the present study was to evaluate Paralichthys olivaceus parvalbumin (PV) following treatment by laccase (LAC) in the presence of propyl gallate (PG) on the structure and potential allergenicity. The structure of LAC + PG treated PV was analyzed through SDS-PAGE, CD, fluorescence, and allergenicity was analyzed by immunological and cell model. Our results showed that LAC + PG treatment can induce structural changes through PV cross-linking. Western blotting and indirect ELISA analysis revealed the decrease in IgG binding capacity of PV, corresponding with the structural changes. The results of in vitro digestion illustrate that LAC + PG treated PV showed more resistance to gastrointestinal digestion compared to untreated PV. The release rate of ß-hexosaminidase and histamine decreased by 35.6% and 66.9%, respectively, with LAC + PG treatment by RBL-2H3 cell assay. Considering the wide utilization of LAC in food industry, our treatment reveals its potential for creation of hypoallergenic fish products under mild reaction conditions.