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Salmonella translocate to the gut epithelium via microfold cells lining the follicle-associated epithelium (FAE). How Salmonella localize to the FAE is not well characterized. Here we use live imaging and competitive assays between wild-type and chemotaxis-deficient mutants to show that Salmonella enterica serotype Typhimurium (S. Typhimurium) localize to the FAE independently of chemotaxis in an ex vivo mouse caecum infection model. Electrical recordings revealed polarized FAE with sustained outward current and small transepithelial potential, while the surrounding villus is depolarized with inward current and large transepithelial potential. The distinct electrical potentials attracted S. Typhimurium to the FAE while Escherichia coli (E. coli) localized to the villi, through a process called galvanotaxis. Chloride flux involving the cystic fibrosis transmembrane conductance regulator (CFTR) generated the ionic currents around the FAE. Pharmacological inhibition of CFTR decreased S. Typhimurium FAE localization but increased E. coli recruitment. Altogether, our findings demonstrate that bioelectric cues contribute to S. Typhimurium targeting of specific gut epithelial locations, with potential implications for other enteric bacterial infections.

PurposeDiabetes mellitus causes diabetic keratopathy (DK). This and other ocular surface disorders are underdiagnosed and problematic for affected patients as well as recipients of diabetic donor corneas. Thus, it is important to find noninvasive means to facilitate determination of the potentially vision-threatening DK. It has been reported that diabetic corneas uptake significantly less oxygen (O2) than healthy controls. However, an integral assessment of the ocular surface is missing.MethodsUsing an optic-fiber O2 micro-sensor (optrode) we demonstrated recently that the healthy ocular surface displays a unique spatiotemporal map of O2 consumption. We hypothesize that diabetes impairs the spatiotemporal profile of O2 uptake at the ocular surface.ResultsUsing streptozotocin (STZ)-induced diabetic mice, we found diminished O2 uptake and loss of the unique pattern across the ocular surface. A diabetic cornea consumes significantly less O2 at the bulbar conjunctiva and limbus, but not the central and peripheral cornea, compared to controls. Further, we show that, contrary to the healthy cornea, the diabetic cornea does not increase the O2 consumption at the limbus in the evening as the normal control.ConclusionsAltogether, our measurements reveal a previously unknown impairment in O2 uptake at the diabetic cornea, making it a potential tool to diagnose ocular surface abnormalities and suggesting a new etiology mechanism.

Recent research has elucidated mechanochemical pathways of single cell polarization, but much less is known about collective motility initiation in adhesive cell groups. We used galvanotactic assays of zebrafish keratocyte cell groups, pharmacological perturbations, electric field switches, particle imaging velocimetry, and cell tracking to show that large cell groups initiate motility in minutes toward the cathode. Interestingly, while PI3K-inhibited single cells are biased toward the anode, inhibiting PI3K does not affect the cathode-directed cell group migration. We observed that control groups had the fastest cathode-migrating cell at the front, while the front cells in PI3K-inhibited groups were the slowest. Both control and PI3K-inhibited groups rapidly repolarized when the electric field direction was reversed, and the group migration continued after the electric field was switched off. Inhibiting myosin disrupted the cohesiveness of keratocyte groups and abolished the collective directionality and ability to switch direction when the electric field is reversed. Our data are consistent with a model according to which cells in the group sense the electric field individually and mechanical integration of the cells results in coherent group motility.

Oxygen (O2) uptake by cells and tissues is a critical indicator of metabolic demand, changes in microenvironment, and pathophysiology. O2 uptake from the atmosphere accounts for virtually all the O2 consumption in the avascular cornea; however, a detailed spatiotemporal profile of corneal O2 uptake (COU) remains undetermined. Here, we used a non-invasive self-referencing optical fiber O2 sensor-the scanning micro-optrode technique (SMOT)-to report the O2 partial pressure and flux variations at the ocular surface of rodents and non-human primates. In vivo spatial mapping in mice revealed a distinct COU, characterized by a centripetal gradient with a significantly higher O2 influx at the limbus and conjunctiva regions than at the center of the cornea. This regional COU profile was reproduced ex vivo in freshly enucleated eyes. The centripetal gradient was conserved across the following species analyzed: mice, rats, and rhesus monkeys. In vivo temporal mapping in mice showed a significant increase in the O2 flux in the limbus in the evening compared to other times. Altogether, the data unveiled a conserved centripetal COU profile, which may be associated with the limbal epithelial stem cells residing at the intersection of the limbus and conjunctiva. These physiological observations will serve as a useful baseline for comparative studies with contact lens wear, ocular disease, diabetes, etc. Moreover, the sensor may be applied to understand the responses of the cornea and other tissues to various insults, drugs, or changes in the environment.

Objective: Studying the broader determinants of anterior open bite (AOB) may guide more equitable policies.This study estimates the prevalence of AOB in Brazilian adolescents and its association with contextual and individual determinants. Methodology: The data for dentofacial anomalies in 15- to 19-year-olds from the National Oral Health Survey SBBrasil 2010 were analysed (N = 4748). AOB was based on the Dental Aesthetic Index (AOB = 0; AOB > 0); the contextual variables were the Human Development Index (HDI) and the Gini Index (2010). The individual sociodemographic variables included sex (male, female), self-reported skin colour/race (white, black, brown, and indigenous + yellow), family income (≥4 minimum wage [MW]; 0–3 MW), and educational attainment (ideal, delayed). The individual clinical variables were decayed, missing, and filled teeth (DMFT) (0, ≥1), first permanent molar loss (0, ≤3, 4), and molar relationship (normal, half cusp, full cusp). Multilevel logistic regression models with random intercepts and fixed slopes were used to estimate odds ratios (ORs) and confidence intervals (95% CIs). Results: AOB prevalence in Brazil was 8.78% (95% CI, 6.85–11.20) at 15 to 19 years of age. The lowest prevalence was in São Luis (2.63%; 95% CI, 0.58–11.03) and the highest was in João Pessoa (29.85%; 95% CI, 15.93–48.85), both capitals of the northeast Brazilian region. A higher prevalence of AOB (OR, 1.71; 95% CI, 1.04–2.80) was observed in municipalities with a lower HDI. Adolescents who declared their skin colour black, with lower family income, with delayed education, with DMFT ≥ 1, who lost 4 permanent first molars, and who had a complete molar cusp relationship were more likely to have AOB. Conclusions: AOB varied amongst Brazilian municipalities. The HDI plays an important role in the prevalence of AOB; individual social determinants have also been associated with AOB malocclusion in adolescents.