Selective Removal of Nitrogen from Quinoline and Petroleum by Pseudomonas ayucida IGTN9m

Enrichment culture experiments employing soil and water samples obtained from petroleum-contaminated environments succeeded in the isolation of a pure culture possessing the ability to utilize quinoline as a sole nitrogen source but did not utilize quinoline as a carbon source. This culture was identified as Pseudomonas ayucida based on a partial 16S rRNA gene sequence, and the strain was given the designation IGTN9m. Examination of metabolites using thin-layer chromatography and gas chromatography-mass spectrometry suggests that P. ayucida IGTN9m converts quinoline to 2-quinolinone and subsequently to 8-hydroxycoumarin. Resting cells of P. ayucida IGTN9m were shown to be capable of selectively removing about 68% of quinoline from shale oil in a 16-h treatment time. These results suggest that P. ayucida IGTN9m may be useful in petroleum biorefining for the selective removal of organically bound nitrogen from petroleum.     

Resibufogenin corrects hypertension in a rat model of human preeclampsia

The study of the pathogenesis of preeclampsia has been hampered by a relative dearth of animal models. We developed a rat model of preeclampsia in which the excretion of a circulating inhibitor of Na/K ATPase, marinobufagenin (MBG), is elevated. These animals develop hypertension, proteinuria, and intrauterine growth restriction. The administration of a congener of MBG, resibufogenin (RBG), reduces blood pressure to normal in these animals, as is the case when given to pregnant animals rendered hypertensive by the administration of MBG. Studies of Na/K ATPase inhibition by MBG and RBG reveal that these agents are equally effective as inhibitors of the enzyme.     

Deadly teamwork: neural cancer stem cells and the tumor microenvironment

Neural cancers display cellular hierarchies with self-renewing tumorigenic cancer stem cells (CSCs) at the apex. Instructive cues to maintain CSCs are generated by both intrinsic networks and the niche microenvironment. The CSC-microenvironment relationship is complex, as CSCs can modify their environment and extrinsic forces induce plasticity in the cellular hierarchy.     

Using maximum entropy to predict the potential distribution of an invasive freshwater snail

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Global change‐driven effects on dissolved organic matter composition: Implications for food webs of northern lakes

Northern ecosystems are experiencing some of the most dramatic impacts of global change on Earth. Rising temperatures, hydrological intensification, changes in atmospheric acid deposition and associated acidification recovery, and changes in vegetative cover are resulting in fundamental changes in terrestrial–aquatic biogeochemical linkages. The effects of global change are readily observed in alterations in the supply of dissolved organic matter (DOM)—the messenger between terrestrial and lake ecosystems—with potentially profound effects on the structure and function of lakes. Northern terrestrial ecosystems contain substantial stores of organic matter and filter or funnel DOM, affecting the timing and magnitude of DOM delivery to surface waters. This terrestrial DOM is processed in streams, rivers, and lakes, ultimately shifting its composition, stoichiometry, and bioavailability. Here, we explore the potential consequences of these global change‐driven effects for lake food webs at northern latitudes. Notably, we provide evidence that increased allochthonous DOM supply to lakes is overwhelming increased autochthonous DOM supply that potentially results from earlier ice‐out and a longer growing season. Furthermore, we assess the potential implications of this shift for the nutritional quality of autotrophs in terms of their stoichiometry, fatty acid composition, toxin production, and methylmercury concentration, and therefore, contaminant transfer through the food web. We conclude that global change in northern regions leads not only to reduced primary productivity but also to nutritionally poorer lake food webs, with discernible consequences for the trophic web to fish and humans.