Aldehyde Pheromones in Lepidoptera: Evidence for an Acetate Ester Precursor in Choristoneura fumiferana

Labeling studies of the eastern spruce budworm in vivo indicate that trans-11-tetradecenyl acetate is synthesized specifically in the pheromone-producing gland and is degraded in concert with pheromone release; hence it may be a precursor to the trans-11-tetradecenal pheromone. Radioactivity from exogenously added labeled fatty acids did not appear to be directly incorporated into the ester, suggesting that de novo biosynthesis from acetate is the major route of ester biosynthesis. Conversion of the acetate ester to alcohol and aldehyde functional groups may be the principal method of regulating pheromone specificity between species of Choristoneura.     

Human T-cell receptor alpha-chain genes: location on chromosome 14

The genes encoding the alpha chain of the human T-cell receptor have been mapped to chromosome 14, the chromosome on which the human immunoglobulin heavy chain locus resides. Thus, genes encoding two different classes of antigen receptor are present on the same chromosome. Furthermore, breaks involving chromosome 14 are frequently seen in tumors of T-cell origin. The potential relation of these chromosome abnormalities to alpha-chain genes is discussed.     

Ultrafast x-ray Thomson scattering of shock-compressed matter

Spectrally resolved scattering of ultrafast K-alpha x-rays has provided experimental validation of the modeling of the compression and heating of shocked matter. The elastic scattering component has characterized the evolution and coalescence of two shocks launched by a nanosecond laser pulse into lithium hydride with an unprecedented temporal resolution of 10 picoseconds. At shock coalescence, we observed rapid heating to temperatures of 25,000 kelvin when the scattering spectra show the collective plasmon oscillations that indicate the transition to the dense metallic plasma state. The plasmon frequency determines the material compression, which is found to be a factor of 3, thereby reaching conditions in the laboratory relevant for studying the physics of planetary formation.     

The 18O/16O and 17O/16O ratios in atmospheric nitrous oxide: A mass-independent anomaly

Measurements of the oxygen isotope ratios (18O/16O and 17O/16O) in atmospheric nitrous oxide (N2O) from La Jolla, Pasadena, and the White Mountain Research Station (elevation, 3801 meters) in California and the White Sands Missile Range in New Mexico show that N2O has a mass-independent composition. These data suggest the presence of a previously undefined atmospheric process. The La Jolla samples can be explained by a mixing between an atmospherically derived source of mass-independent N2O and biologically derived mass-dependent N2O. Possible origins of the mass-independent anomaly in N2O are discussed.