Kevin G Hicks

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Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range of main categories of ecosystems, from arctic and boreal(More)
The functional spectrum of a secretion system is defined by its substrates. Here we analyzed the secretomes of Pseudomonas aeruginosa mutants altered in regulation of the Hcp Secretion Island-I-encoded type VI secretion system (H1-T6SS). We identified three substrates of this system, proteins Tse1-3 (type six exported 1-3), which are coregulated with the(More)
Tropospheric ozone and black carbon (BC) contribute to both degraded air quality and global warming. We considered ~400 emission control measures to reduce these pollutants by using current technology and experience. We identified 14 measures targeting methane and BC emissions that reduce projected global mean warming ~0.5°C by 2050. This strategy avoids(More)
Acidification represents a growing threat to certain developing country ecosystems in tropical and subtropical climates. A methodology investigating the extent of acidification risks from sulfur emissions on a global scale is presented. Atmospheric transfer models have been used to calculate transfer and deposition of sulfur (using emissions for 1990 and a(More)
The larva of the green lacewing Chrysopa slossonae lives in colonies of the wooly alder aphid Prociphilus tesselatus upon which it feeds. It disguises itself as its prey by plucking some of the waxy "wool" from the bodies of the aphids and applying this material to its own back. The investiture protects it from assault by the ants that ordinarily "shepherd"(More)
There is little evidence that nitrogen (N) cycling in the highly weathered, low-phosphorus (P), acidic soils found in Southern Hemisphere continents will differ greatly from that in North America and Europe. Evidence from the 'south' shows: the similarity in forms and temporal patterns in losses of N from different land uses; that the C:N ratios of the(More)
The defensive secretion of larvae of the chrysomelid beetle Plagiodera versicolora contains two unstable, volatile methylcyclopentanoid terpenes: a dialdehyde (chrysomelidial) isomeric with dolichodial and anisomorphal, and a closely related enol lactone (plagiolactone). Chrysomelidial and plagiolactone are shown to have structures III and IV on the basis(More)
pH sensing is crucial for survival of most organisms, yet the molecular basis of such sensing is poorly understood. Here, we present an atomic resolution structure of the periplasmic portion of the acid-sensing chemoreceptor, TlpB, from the gastric pathogen Helicobacter pylori. The structure reveals a universal signaling fold, a PAS domain, with a molecule(More)
Helicobacter pylori moves in response to environmental chemical cues using a chemotaxis two-component signal-transduction system. Autoinducer-2 (AI-2) is a quorum-sensing signal produced by the LuxS protein that accumulates in the bacterial environment in a density-dependent manner. We showed previously that a H. pylori luxS mutant was defective in motility(More)
Productive intercellular delivery of cargo by secretory systems requires exquisite temporal and spatial choreography. Our laboratory has demonstrated that the haemolysin co-regulated secretion island I (HSI-I)-encoded type VI secretion system (H1-T6SS) of Pseudomonas aeruginosa transfers effector proteins to other bacterial cells. The activity of these(More)