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This study investigated the antimicrobial and antibiofilm efficacy of separate and combined treatments of Lactobacillus curvatus B67-produced postbiotic and the polyphenolic flavanol quercetin against Listeria monocytogenes and Salmonella enterica ser. Typhimurium. The antimicrobial potentiality of the postbiotic was chiefly associated with organic acids (e.g., lactic and acetic acids). At sub-minimum inhibitory concentration (1/2 MIC), the postbiotic and quercetin effectively reduced the pathogenic biofilm cells on processed pork sausage and meat-processing surfaces (e.g., stainless-steel and rubber). Moreover, the postbiotic exhibited strong residual antimicrobial efficacy over diverse pH and temperature ranges. In addition, the combination of postbiotic with quercetin increased the leakage of pathogenic intracellular metabolites (e.g., nucleic acids and protein) and inhibited pathogenic biofilm formation on both biotic and abiotic surfaces. Therefore, this study confirmed that lactic acid bacteria-derived postbiotic and plant-derived quercetin could be used as potential alternative bioprotective agents in the meat processing industry.

Foodborne pathogen-mediated biofilms in food processing environments are severe threats to human lives. In the interest of human and environmental safety, natural substances with antimicrobial properties and generally regarded as safe (GRAS) status are the futuristic disinfectants of the food industry. In this study, the efficacy of bioactive, soluble products (metabolic by-products) from lactic acid bacteria (LAB) and plant-derived essential oils (EO) were investigated as biocidal agents. The postbiotic produced by kimchi-derived Leuconostoc mesenteroides J.27 isolate was analyzed for its metabolic components to reveal its antimicrobial potential against three pathogenic microorganisms (Vibrio parahaemolyticus, Pseudomonas aeruginosa, and Escherichia coli). Additionally, the efficacy of food-grade EO (eugenol and thymol, respectively) was also assessed in our study. Determination of the minimum inhibitory concentration (MIC) of postbiotic and EO against three tested pathogens revealed that the sub-MIC (0.5 MIC) of postbiotic and EO could efficiently inhibit the biofilm formation on both seafood (squid) and seafood-processing surfaces (rubber and low-density polyethylene plastic). Moreover, the polymerase chain reaction (PCR) analysis confirmed that the LAB J.27 isolate possesses bacteriocin- and enzyme-coding genes. The residual antibacterial activity of the produced postbiotic was maintained over a diverse pH range (pH 1-6) but was entirely abolished at neutral or higher pH values. However, the activity was unaffected by exposure to high temperatures (100 and 121 °C) and storage (30 days). Notably, the leakage of intracellular metabolites, damage to DNA, and the down-regulation of biofilm-associated gene expression in the pathogens increased significantly (p 0.05) following the combination treatment of postbiotic with thymol compared to postbiotic with eugenol. Nonetheless, all in vitro results indicated the prospective use of combining Leu. mesenteroides J.27-derived postbiotic with both EO as a "green preservative" in the seafood industry to inhibit the formation of pathogenic microbial biofilms.

Lactic acid bacteria (LAB) with probiotic potential have become highly sought-after by global consumers due to their wide applicability. Here, two LAB strains (J.27 and M.21) were isolated from a traditional Korean fermented vegetable (kimchi) and identified via 16S rRNA gene sequence analyses. Afterward, the two LAB isolates were evaluated for their antibiofilm activity against three foodborne pathogens (Vibrio parahaemolyticus, Pseudomonas aeruginosa, and Escherichia coli) on a seafood model (squid) and food-contact surfaces (rubber and high-density polyethylene [HDPE] plastic). This study also evaluated the effect of co-culture with LAB isolates on the relative expression of different virulence- and quorum sensing (QS)-associated genes from the three aforementioned pathogens. Our antimicrobial and genetic analyses revealed that the combined LAB isolates exhibited higher planktonic and biofilm cell inhibition on both biotic and abiotic surfaces after co-culture with the three mentioned foodborne pathogens assessed for 24 h. However, the antimicrobial activities of both LAB isolates were higher on abiotic surfaces (HDPE) than on biotic surfaces (squid). Therefore, the results of our in vitro experiments highlighted the potential applicability of both LAB isolates as “green” bioprotective agents against pathogenic microorganisms in the seafood industry.

In 1991 Tratnik derived two systems of multivariable orthogonal Wilson polynomials and considered their limit cases. q-Analogues of these systems are derived, yielding systems of multivariable orthogonal Askey-Wilson polynomials and their special and limit cases., Comment: 9 pages. To appear in Theory and Applications of Special Functions. A volume dedicated to Mizan Rahman, M. E. H. Ismail and E. Koelink, eds., Dev. Math., Kluwer Acad. Publ., Dordrecht

The main goal is to interpret the Askey-Wilson function and the corresponding transform pair on the quantum SU(1,1) group. A weight on the C^*-algebra of continuous functions vanishing at infinity on the quantum SU(1,1) group is studied, which is left and right invariant in a weak sense with respect to a product defined using Wall functions. The Haar weight restricted to certain subalgebras are explicitly determined in terms of an infinitely supported Jackson integral and in terms of an infinitely supported Askey-Wilson type measure. For the evaluation the spectral analysis of explicit unbounded doubly infinite Jacobi matrices and some new summation formulas for basic hypergeometric series are needed. The spherical functions are calculated in terms of Askey-Wilson functions and big q-Jacobi functions. The corresponding spherical Fourier transforms are identified with special cases of the big q-Jacobi function transform and of the Askey-Wilson function transform., Comment: 77 pages, 1 figure. Appendix by Mizan Rahman

Here are the latest errata, etc., to the Gasper and Rahman "Basic Hypergeometric Series" book. Any additional errata will be added to the end of the last list., Comment: Additional errata and material added

We find the raising and lowering operators for orthogonal polynomials on the unit circle introduced by Szeg�� and for their four parameter generalization to ${}_4��_3$ biorthogonal rational functions on the unit circle.