Pathogenic Neisseria Hitchhike on the Uropod of Human Neutrophils

Polymorphonuclear neutrophils (PMNs) are important components of the human innate immune system and are rapidly recruited at the site of bacterial infection. Despite the effective phagocytic activity of PMNs, Neisseria gonorrhoeae infections are characterized by high survival within PMNs. We reveal a novel type IV pilus-mediated adherence of pathogenic Neisseria to the uropod (the rear) of polarized PMNs. The direct pilus-uropod interaction was visualized by scanning electron microscopy and total internal reflection fluorescence (TIRF) microscopy. We showed that N. meningitidis adhesion to the PMN uropod depended on both pilus-associated proteins PilC1 and PilC2, while N. gonorrhoeae adhesion did not. Bacterial adhesion elicited accumulation of the complement regulator CD46, but not I-domain-containing integrins, beneath the adherent bacterial microcolony. Electrographs and live-cell imaging of PMNs suggested that bacterial adherence to the uropod is followed by internalization into PMNs via the uropod. We also present data showing that pathogenic Neisseria can hitchhike on PMNs to hide from their phagocytic activity as well as to facilitate the spread of the pathogen through the epithelial cell layer

Limits and possibilities in the geolocation of humans using multiple isotope ratios (H, O, N, C) of hair from east coast cities of the USA

NoWe examined multiple natural abundance isotope ratios of human hair to assess biological variability within and between geographic locations and, further, to determine how well these isotope values predict location of origin. Sampling locations feature differing seasonality and mobile populations as a robust test of the method. Serially-sampled hair from Cambridge, MA, USA, shows lower δ2 H and δ18 O variability over a one-year time course than model-predicted precipitation isotope ratios, but exhibits considerable differences between individuals. Along a ∼13° northsouth transect in the eastern USA (Brookline, MA, 42.3 ° N, College Park, MD, 39.0 ° N, and Gainesville, FL, 29.7 ° N) δ18 O in human hair shows relatively greater differences and tracks changes in drinking water isotope ratios more sensitively than δ2 H. Determining the domicile of humans using isotope ratios of hair can be confounded by differing variability in hair δ18 O and δ2 H between locations, differential incorporation of H and O into this protein and, in some cases, by tap water δ18 O and δ2 H that differ significantly from predicted precipitation values. With these caveats, randomly chosen people in Florida are separated from those in the two more northerly sites on the basis of the natural abundance isotopes of carbon, nitrogen, hydrogen, and oxygen.This work was partially supported by the National Geospatial Agency under grant [HM1582-08-0024].Originally presented at the IAEA International Symposium on Isotope Hydrology: Revisiting Foundations and Exploring Frontiers, 11–15 May 2015, Vienna, Austri

A geochemical study of the impact of irrigation and aquifer lithology on groundwater in the Upper Yakima River Basin, Washington, USA

The Yakima River, a major tributary of the Columbia River, is currently overallocated in its surface water usage in part because of large agricultural water use. As a result, groundwater availability and surface water/groundwater interactions have become an important issue in this area. In several sub-basins, the Yakima River water is diverted and applied liberally to fields in the summer creating artificial recharge of shallow groundwater. Major ion, trace element, and stable isotope geochemistry of samples from 26 groundwater wells from a transect across the Yakima River and 24 surface waters in the Kittitas sub-basin were used to delineate waters with similar geochemical signatures and to identify surface water influence on groundwater. Major ion chemistry and stable isotope signatures combined with principal component analysis revealed four major hydrochemical groups. One of these groups, collected from shallow wells within the sedimentary basin fill, displays temporal variations in NO3 and SO4 along with high δ18O and δD values, indicating significant contribution from Yakima River and/or irrigation water. Two other major hydrochemical groups reflect interaction with the main aquifer lithologies in the basin: the Columbia River basalts (high-Na groundwaters), and the volcaniclastic rocks of the Ellensburg Formation (Ca–Mg–HCO3 type waters). The fourth major group has interacted with the volcaniclastic rocks and is influenced to a lesser degree by surface waters. The geochemical groupings constrain a conceptual model for groundwater flow that includes movement of water between underlying Columbia River basalt and deeper sedimentary basin fill and seasonal input of irrigation water