Background Environmental pollutants, which coexist with allergens, have been associated with the exacerbation of asthma. However, the underlying molecular mechanisms remain elusive. We sought to determine whether benzo(a)pyrene (BaP) co‐exposure with dermatophagoides group 1 allergen (Der f 1) can potentiate Der f 1‐induced asthma and its underlying mechanisms. Methods The effect of BaP was investigated in Der f 1‐induced mouse model of asthma, including airway hyper‐responsiveness, allergic inflammation, and epithelial‐derived cytokines. The impact of BaP on Der f 1‐induced airway epithelial cell oxidative stress (ROS) and cytokine release was further analyzed. The role of aryl hydrocarbon receptor (AhR) signaling in BaP‐promoted Der f 1‐induced ROS, cytokine production, and allergic inflammation was also investigated. Results Compared with Der f 1, BaP co‐exposure with Der f 1 led to airway hyper‐responsiveness and increased lung inflammation in mouse model of asthma. Increased expression of TSLP, IL‐33, and IL‐25 was also found in the airways of these mice. Moreover, BaP co‐exposure with Der f 1 activated AhR signaling with increased expression of AhR and CYP1A1 and promoted airway epithelial ROS generation and TSLP and IL‐33, but not IL‐25, expression. Interestingly, AhR antagonist CH223191 or cells with AhR knockdown abrogated the increased expression of ROS, TSLP, and IL‐33. Furthermore, ROS inhibitor N‐acetyl‐L‐cysteine (NAC) also suppressed BaP co‐exposure‐induced expression of epithelial TSLP, IL‐33, and IL‐25. Finally, AhR antagonist CH223191 and NAC inhibited BaP co‐exposure with Der f 1‐induced lung inflammation. Conclusions Our findings suggest that BaP facilitates Der f 1‐induced epithelial cytokine release through the AhR‐ROS axis.

Using genetic markers defined previously in the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA (rDNA), isotopic, and non-isotopic polymerase-chain-reaction-coupled single-strand conformation polymorphism (SSCP) were utilized to identify each of three anisakid species [Anisakis simplex (s.l.), Contracaecum osculatum (s.l.), and Hysterothylacium aduncum] from different host species and geographical locations in Poland and Sweden. While subtle microheterogeneity was observed within each of Anisakis simplex (s.l.) and H. aduncum, distinct SSCP profiles were displayed for each of the three species, allowing identification and differentiation of the three taxa. Subsequent sequencing of the ITS-1 and ITS-2 rDNA revealed that A. simplex (s.l.) represented Anisakis simplex s.s. and Contracaecum osculatum (s.l.) represented C. osculatum C. Application of the non-isotopic SSCP assay of ITS-2 to larval anisakid samples from different hosts and geographical locations in China revealed three distinct SSCP profiles, one of which was consistent with that of A. simplex (s.l.), and the other two had different SSCP profiles from that of C. osculatum C and H. aduncum. Sequencing of the ITS-1 and ITS-2 rDNA for representative Chinese anisakid samples examined revealed three anisakid species in China, i.e., Anisakis typica, Anisakis pegreffii, and Hysterothylacium sp. These molecular tools will be useful for identification and investigation of the ecology of anisakid nematodes in China and elsewhere.

Cronobacter spp. is an emerging pathogen that causes meningitis, sepsis, bacteremia, and necrotizing enterocolitis in neonates and children. The present study developed an assay integrating real-time PCR and high resolution melting (HRM) analysis targeting the OmpA gene for the specific detection and rapid identification of Cronobacter spp. (formerly Enterobacter sakazakii) in powdered infant formula. Eleven Cronobacter field isolates and 25 reference strains were examined using one pair of primers, having the accuracy of 100% in reference to conventional methods. The assay was proved to be highly sensitive with a detection limit of 102 CFU/ml without pre-enrichment, and highly concordant (100%) when compared with ISO-IDF 22964 in 89 actual samples. The method performed for Cronobacter spp. detection was less than 24 h, drastically shortened, compared to several days using standard culturing method, it is probe-free and reduces a risk of PCR carryover. Moreover, all Cronobacter strains examined in this study were genotyped into two species according to their HRM profiles. The established method should provide a molecular tool for direct detection and simultaneous genotyping of Cronobacter spp. in powdered infant formula.