An interneuronal chemoreceptor required for olfactory imprinting in C. elegans

Animals alter their behavioral patterns in an experience-dependent manner. Olfactory imprinting is a process in which the exposure of animals to olfactory cues during specific and restricted time windows leaves a permanent memory ("olfactory imprint") that shapes the animal's behavior upon encountering the olfactory cues at later times. We found that Caenorhabditis elegans displays olfactory imprinting behavior that is mediated by a single pair of interneurons. To function in olfactory imprinting, this interneuron pair must express a G protein-coupled chemoreceptor family member encoded by the sra-11 gene. Our study provides insights into the cellular and molecular basis of olfactory imprinting and reveals a function for a chemosensory receptor family member in interneurons.     

Antarctic soft-bottom benthos in oligotrophic and eutrophic environments

The benthos of the east and west sides of McMurdo Sound, Antarctica, is characterized by dramatically different infaunal assemblages. The eutrophic East Sound has higher infaunal densities than almost any other benthic assemblage in the world. In contrast, the oligotrophic West Sound, bathed by currents from beneath the Ross Ice Shelf, has patterns of mobile epifauna and low infauna density similar to bathyl deep-sea communities.     

Probing the structure of the deep continental crust

Old, buried, deformed, crystalline rocks apparently make up most of the 40-kilometer-thick continental crust. This part of the earth is poorly explored and constitutes a major frontier of modern earth science. Two techniques, seismic reflection profiling and drilling, which were developed by industry for other purposes, offer special potential for such exploration. Seismic profiling of the deep crust by COCORP (the Consortium for Continental Reflection Profiling) has already produced important information, including evidence for extensive thin-skinned thrusting of older rocks over a continental margin as the corresponding ocean basin closed. Deep drilling of crystalline rocks of the continents for scientific purposes is so far relatively unexploited in the United States but is already being carried on elsewhere. In general, big science is likely to become more important in basic geology as this frontier is explored.     

Mantophasmatodea: a new insect order with extant members in the Afrotropics

A new insect order, Mantophasmatodea, is described on the basis of museum specimens of a new genus with two species: Mantophasma zephyra gen. et sp. nov. (one female from Namibia) and M. subsolana sp. nov. (one male from Tanzania). This is the first time since 1914 that a newly described extant insect taxon has proved unplaceable within a recognized order. Mantophasmatodeans are apterous carnivores. Their closest phylogenetic relationships may be to Grylloblattodea (ice-crawlers) and/or Phasmatodea (stick insects), but the morphological evidence is ambiguous. Raptophasma Zompro from Baltic amber is assigned to the Mantophasmatodea, revealing a wider previous range for the lineage.     

Preparing protein microarrays by soft-landing of mass-selected ions

Intact, multiply protonated proteins of particular mass and charge were selected from ionized protein mixtures and gently landed at different positions on a surface to form a microarray. An array of cytochrome c, lysozyme, insulin, and apomyoglobin was generated, and the deposited proteins showed electrospray ionization mass spectra that matched those of the authentic compounds. Deposited lysozyme and trypsin retained their biological activity. Multiply charged ions of protein kinase A catalytic subunit and hexokinase were also soft-landed into glycerol-based liquid surfaces. These soft-landed kinases phosphorylated LRRASLG oligopeptide and D-fructose, respectively.     

Functional conversion between A-type and delayed rectifier K+ channels by membrane lipids

Voltage-gated potassium (Kv) channels control action potential repolarization, interspike membrane potential, and action potential frequency in excitable cells. It is thought that the combinatorial association between distinct alpha and beta subunits determines whether Kv channels function as non-inactivating delayed rectifiers or as rapidly inactivating A-type channels. We show that membrane lipids can convert A-type channels into delayed rectifiers and vice versa. Phosphoinositides remove N-type inactivation from A-type channels by immobilizing the inactivation domains. Conversely, arachidonic acid and its amide anandamide endow delayed rectifiers with rapid voltage-dependent inactivation. The bidirectional control of Kv channel gating by lipids may provide a mechanism for the dynamic regulation of electrical signaling in the nervous system.