No abstract

Foodborne pathogens like Listeria monocytogenes can cause various illnesses and pose a serious threat to public health. They produce species-specific microbial volatile organic compounds, i.e., the biomarkers, making it possible to indirectly measure microbial contamination in foodstuff. Herein, highly ordered mesoporous tungsten oxides with high surface areas and tunable pores have been synthesized and used as sensing materials to achieve an exceptionally sensitive and selective detection of trace Listeria monocytogenes. The mesoporous WO-based chemiresistive sensors exhibit a rapid response, superior sensitivity, and highly selective detection of 3-hydroxy-2-butanone. The chemical mechanism study reveals that acetic acid is the main product generated by the surface catalytic reaction of the biomarker molecule over mesoporous WO. Furthermore, by using the mesoporous WO-based sensors, a rapid bacteria detection was achieved, with a high sensitivity, a linear relationship in a broad range, and a high specificity for Listeria monocytogenes. Such a good gas sensing performance foresees the great potential application of mesoporous WO-based sensors for fast and effective detection of microbial contamination for the safety of food, water safety and public health.

In the course of a large-scale program of ENU mutagenesis, we isolated a dominant mutation, called Velvet. The mutation was found to be uniformly lethal to homozygotes, which do not survive E13.5. Mice heterozygous for the Velvet mutation are born with eyelids open and demonstrate a wavy coat and curly vibrissae. The mutation was mapped to the proximal end of chromosome 11 by genome-wide linkage analysis. On 249 meioses, the locus was confined to a 2.7-Mb region, which included the epidermal growth factor receptor gene (Egfr). An A → G transition in the Egfr coding region of Velvet mice was identified, causing the amino acid substitution D833G. This substitution alters an essential triad of amino acids (DFG → GFG) that is normally required for coordination of the ATP substrate. As such, kinase activity is at least mostly abolished, but quaternary structure of the receptor is presumably maintained, accounting for the dominant effect. Velvet is the first known dominant representative of the Egfr allelic series that is fully viable, a fact that makes it particularly useful for developmental studies.T HE mammalian genome is believed to encompass cells. Mutations that disrupt the signaling interactions ‫000,04-000,03ف‬ genes (Lander et al. 2001; Venter between epithelium and the underlying mesenchyme et al. 2001), but the number of phenotypes cataloged can cause eyelid closure defects. Some examples include to date is much smaller than this, and, hence, it may recessive mutations in the Tgf␣, Egfr, MEKK-1, and Fgfr2 be said that the essential function of most genes remains loci (Luetteke et al. 1993(Luetteke et al. , 1994Mann et al. 1993; Yujiri undetermined (Brown and Peters 1996) In the course of a large-scale ENU mutagenesis be resolved by positional cloning. In this report, we screening effort carried out in our laboratory, a domifocus on the development of the eyelids in mice, which nant mutation (Velvet) was identified among a total of undergo specific developmental changes both in utero 16,606 F 1 mice born to mutagenized C57BL/6 males and during early postnatal life.and normal C57BL/6 females. The designation "Velvet" Under normal circumstances, the eyelids begin to grow across the surface of the developing eye at E12.5.refers to the velvet-like texture of the coat of affected Between days 14 and 16 of gestation, the top and bottom animals. However, Velvet mice are born with eyelids eyelids continue to flatten, come to lie in close approxiopen and with curled vibrissae as well. They present a mation to one another, and finally fuse tightly with each phenotype very similar to that of waved-1 and waved-2 other at E16.5. They remain fused until ‫21ف‬ days after mice. Although two similar phenotypes (so far unbirth (Findlater et al. 1993). Failure of fusion leads to mapped) have been observed among 23,221 F 3 animals a readily apparent "open-eyelids-at-birth" defect. Eyelid generated and weaned to date, Velvet was the sole domiclosure is a process involving the migration of epithelial nant mutation of i...

Biofilms, which are complex microbial communities embedded in the protective extracellular polymeric substances (EPS), are difficult to remove in food production facilities. In this study, the use of acidic electrolyzed water (AEW) to remove foodborne pathogen biofilms was evaluated. We used a green fluorescent protein-tagged Escherichia coli for monitoring the efficiency of AEW for removing biofilms, where under the optimal treatment conditions, the fluorescent signal of cells in the biofilm disappeared rapidly and the population of biofilm cells was reduced by more than 67%. Additionally, AEW triggered EPS disruption, as indicated by the deformation of the carbohydrate C-O-C bond and deformation of the aromatic rings in the amino acids tyrosine and phenylalanine. These deformations were identified by EPS chemical analysis and Raman spectroscopic analysis. Scanning electron microscopy (SEM) images confirmed that the breakup and detachment of biofilm were enhanced after AEW treatment. Further, AEW also eradicated biofilms formed by both Gram-negative bacteria (Vibrio parahaemolyticus) and Gram-positive bacteria (Listeria monocytogenes) and was observed to inactivate the detached cells which are a potential source of secondary pollution. This study demonstrates that AEW could be a reliable foodborne pathogen biofilm disrupter and an eco-friendly alternative to sanitizers traditionally used in the food industry.