ZnO nanoparticles impose a panmetabolic toxic effect along with strong necrosis, inducing activation of the envelope stress response in Salmonella enterica serovar Enteritidis.

In this study, we tested the antimicrobial activity of three metal nanoparticles (NPs), ZnO, MgO, and CaO NPs, against Salmonella enterica serovar Enteritidis in liquid medium and on solid surfaces. Out of the three tested metal NPs, ZnO NPs exhibited the most significant antimicrobial effect both in liquid medium and when embedded on solid surfaces. Therefore, we focused on revealing the mechanisms of surface-associated ZnO biocidal activity. Using the global proteome approach, we report that a great majority (79%) of the altered proteins in biofilms formed by Salmonella enterica serovar Enteritidis were downregulated, whereas a much smaller fraction (21%) of proteins were upregulated. Intriguingly, all downregulated proteins were enzymes involved in a wide range of the central metabolic pathways, including translation; amino acid biosynthetic pathways; nucleobase, nucleoside, and nucleotide biosynthetic processes; ATP synthesis-coupled proton transport; the pentose phosphate shunt; and carboxylic acid metabolic processes, indicating that ZnO NPs exert a panmetabolic toxic effect on this prokaryotic organism. In addition to their panmetabolic toxicity, ZnO NPs induced profound changes in cell envelope morphology, imposing additional necrotic effects and triggering the envelope stress response of Salmonella serovar Enteritidis. The envelope stress response effect activated periplasmic chaperones and proteases, transenvelope complexes, and regulators, thereby facilitating protection of this prokaryotic organism against ZnO NPs.

Long-term survival of women with epithelial ovarian cancer detected by ultrasonographic screening.

OBJECTIVE: To estimate the effect of ultrasonographic screening on stage at detection and long-term disease-specific survival of women with epithelial ovarian cancer. METHODS: Eligibility included all asymptomatic women aged 50 years and older and women aged 25 years and older with a documented family history of ovarian cancer. From 1987 to 2011, 37,293 women received annual ultrasonographic screening. Women with abnormal screens underwent tumor morphology indexing, serum biomarker analysis, and surgery. RESULTS: Forty-seven invasive epithelial ovarian cancers and 15 epithelial ovarian tumors of low malignant potential were detected. No women with low malignant potential tumors experienced recurrent disease. Stage distribution for invasive epithelial cancers was: stage I, 22 (47%); stage II, 11 (23%); stage III, 14 (30%), and stage IV, 0 (0%). Follow-up varied from 2 months to 20.1 years (mean, 5.8 years). The 5-year survival rate for invasive epithelial ovarian cancers detected by screening was: stage I, 95%±4.8%; stage II, 77.1%±14.5%; and stage III, 76.2%±12.1%. The 5-year survival rate for all women with invasive epithelial ovarian cancer detected by screening as well as interval cancers was 74.8%±6.6% compared with 53.7%±2.3% for unscreened women with ovarian cancer from the same institution treated by the same surgical and chemotherapeutic protocols (P<.001). CONCLUSION: Annual ultrasonographic screening of asymptomatic women achieved increased detection of early-stage ovarian cancer cases and an increase in 5-year disease-specific survival rate for women with ovarian cancer. LEVEL OF EVIDENCE: II.