Evidence for a Diagenetic Origin of Vera Rubin Ridge, Gale Crater, Mars: Summary and Synthesis of Curiosity's Exploration Campaign.

This paper provides an overview of the Curiosity rover's exploration at Vera Rubin ridge (VRR) and summarizes the science results. VRR is a distinct geomorphic feature on lower Aeolis Mons (informally known as Mount Sharp) that was identified in orbital data based on its distinct texture, topographic expression, and association with a hematite spectral signature. Curiosity conducted extensive remote sensing observations, acquired data on dozens of contact science targets, and drilled three outcrop samples from the ridge, as well as one outcrop sample immediately below the ridge. Our observations indicate that strata composing VRR were deposited in a predominantly lacustrine setting and are part of the Murray formation. The rocks within the ridge are chemically in family with underlying Murray formation strata. Red hematite is dispersed throughout much of the VRR bedrock, and this is the source of the orbital spectral detection. Gray hematite is also present in isolated, gray-colored patches concentrated toward the upper elevations of VRR, and these gray patches also contain small, dark Fe-rich nodules. We propose that VRR formed when diagenetic event(s) preferentially hardened rocks, which were subsequently eroded into a ridge by wind. Diagenesis also led to enhanced crystallization and/or cementation that deepened the ferric-related spectral absorptions on the ridge, which helped make them readily distinguishable from orbit. Results add to existing evidence of protracted aqueous environments at Gale crater and give new insight into how diagenesis shaped Mars' rock record.

Pigeon and dove eggwhite protect mice against renal infection due to P fimbriated Escherichia coli.

Pigeon and dove eggwhite exhibit high level P1 antigenic activity and are potent and specific inhibitors of adherence mediated by P fimbriae of uropathogenic Escherichia coli. To evaluate pigeon and dove eggwhite as P fimbrial receptor analogues in the prevention of ascending renal infection, mice were challenged with a P fimbriated E. coli urosepsis isolate suspended in saline alone or in saline plus various inhibitors of adherence, including D-mannose, globoside, and chicken, dove, and pigeon eggwhite. D-mannose inhibited mannose-sensitive adherence but not P fimbrial adherence, and failed to prevent renal infection. Globoside and chicken eggwhite also failed to inhibit P fimbrial adherence; chicken eggwhite had little and globoside had no impact on renal infection. In contrast, dove and pigeon eggwhite eliminated P fimbrial adherence and significantly reduced the incidence and intensity of renal infection. These findings suggest that pigeon and dove eggwhite provide P1-antigen-specific protection against ascending renal infection in mice due to P fimbriated uropathogenic E. coli.

Avian P1 antigens inhibit agglutination mediated by P fimbriae of uropathogenic Escherichia coli.

Whole egg white from pigeon, dove, and cockatiel eggs, as well as the ovomucoid fraction of pigeon egg white, exhibited strong P1 antigenic activities and inhibited agglutination of human P1 erythrocytes and of digalactoside-coated latex beads by P-fimbriated Escherichia coli strains. In contrast, chicken egg white exhibited only weak P1 antigenic activity and had little impact on P-fimbrial agglutination. These preparations did not affect hemagglutination by E. coli strains expressing mannose-resistant adhesins other than P fimbriae, i.e., Dr, F1845, and S adhesins. Human anti-P1 serum diminished the P-fimbrial inhibitory activities of pigeon egg white and pigeon ovomucoid. Pigeon ovomucoid was equipotent on a molar basis with globoside, and the pigeon, dove, and cockatiel egg white preparations were equipotent with each other in P-fimbrial inhibition. Incubation of p erythrocytes in whole egg whites or in pigeon ovomucoid did not render them agglutinable by P-fimbriated bacteria, whereas incubation in globoside did. These data demonstrate that whole egg whites (and their ovomucoid fraction) from members of the families Columbidae (pigeons and doves) and Psittacidae (parrots) specifically and potently inhibit P-fimbrial agglutination, probably by providing P1 antigen as a receptor for the P-fimbrial adhesin. Avian egg white preparations may facilitate adhesin characterization of wild-type uropathogenic strains and may useful in preventing upper urinary tract infections due to P-fimbriated E. coli.