Article 3 (Source: Applied and Environmental Microbiology, 2021, DOI: 10.1128/AEM.02380- 20)       The occurrence of viable-but-nonculturable (VBNC) bacteria poses a potentialrisk to food safety due to failure in conventional colony detection. In this study,induction of VBNC Staphylococeus aureus was conducted by exposure to anatmospheric-pressure air dielectric barrier dischargo-nonthermal-plasma (DBD-NTP)treatment with an applied energy of 8.1 kJ. The stress resistance profiles andpathogenicity of VBNC S. aureus were further evaluated. We found that VBNC S.aureus showed levels of tolerance of heat, acid, and osmosis challenges comparable tothose shown by culturable S. aureus, while VBNC S. aureus exhibited enhancedresistance to oxidative and antibiotic stress, relating to the mechanisms of cellularenergy depletion, antioxidant response initiation, and multidrug efflux pumpupregulation. Regarding pathogenicity, NTP-induced VBNC S. aureus retained thecapacity to infect the HeLa host cells. Compared with the culturable counterparts,VBNC S. aureus caused reduced immune responses (Toll-like receptor [TLR],nucleotide-binding oligomerization domain [NOD]) in HeLa cells, which wasattributed to suppression of biosynthesis of the recognized surface ligands (e.g,peptidoglycan). Additionally, the proteomic analysis revealed that upregulation ofseveral virulence factors (CIB, SdrD, SCIN, SasH, etc.) could ensure that VBNC S.aureus would adhere to and internalize into host cells and avoid the host attack. Thecamouflaged mechanisms described above led to VBNC S. aureus causing less damageto the host cells, and their activity might result in longer intracellular persistence, posingpotential risks during NTP processing        The cons umer demand for freshness and nutrition has accelerated the developmentof mild decont ntamination technologies. The incomplete killing of nonthermal (NT)treatments might induce pathogens to enter into a viable-but-nonculturable (VBNC)status as a survival strategy. The use of nonthermal plasma (NTP) as a novel fooddecontamination technology received increased attention in food industry during recentdecades. Our previous work confirned that the foodborne pathogen S. aureus wasinduced into VBNC status in response to NTP exposure. This work further revealed thedevelopment of stress resistance and vinalence retention of NTP-induced VBNC S.aureus through the mechanisms of energy suppression, oxidative stress defense, andimmune escape. The data provide fundamental knowledge of the potential risks posedby NTP-induced VBNC S. aureus, which require further parameter optimization of theNTP process or combination with other techniques to avoid the occurrence of VBNCbacteria.
【題組】21. Which word is close to the meaning of "camoutlaged" mechanisms in the abstract?
(A) Important
(B) Necessary
(C) Hiding
(D) Internalization.