Evidence for chain molecules enriched in carbon, hydrogen, and oxygen in comet halley

In situ measurements of the composition and spatial distribution of heavy thermal positive ions in the coma of comet Halley were made with the heavy-ion analyzer RPA2-PICCA aboard the Giotto spacecraft. Above 50 atomic mass units an ordered series of mass peaks centered at 61, 75, 91, and 105 atomic mass units were observed. Each peak appears to be composed of three or more closely spaced masses. The abundances decrease and the dissociation rates increase smoothly with increasing mass. These observations suggest the presence of chain molecules that are enriched in carbon, oxygen, and hydrogen, such as polyoxymethylene (polymerized formaldehyde), in comet Halley.     

"Coulomb Staircase" at Room Temperature in a Self-Assembled Molecular Nanostructure

Double-ended aryl dithiols [alpha,alpha'-xylyldithiol (XYL) and 4,4'-biphenyldithiol] formed self-assembled monolayers (SAMs) on gold(111) substrates and were used to tether nanometer-sized gold clusters deposited from a cluster beam. An ultrahigh-vacuum scanning tunneling microscope was used to image these nanostructures and to measure their current-voltage characteristics as a function of the separation between the probe tip and the metal cluster. At room temperature, when the tip was positioned over a cluster bonded to the XYL SAM, the current-voltage data showed "Coulomb staircase" behavior. These data are in good agreement with semiclassical predictions for correlated single-electron tunneling and permit estimation of the electrical resistance of a single XYL molecule (approximately18 ± 12 megohms).     

Hydrolysis at arginylproline in polypeptides by clostridiopeptidase B

Clostridiopeptidase B, a sulfhydryl protease from Clostridium histolyticum, hydrolyzes the arginylproline bond in the synthetic polypeptide methionyllysyl-bradykinin. Hydrolysis also occurs at a reduced rate at the lysylarginine bond, further delineating the environment necessary for the minor proteolysis seen with this enzyme at lysine residues. The specificity of clostridiopeptidase B differs from trypsin, which hydrolyzes this synthetic polypeptide only at the lysylarginine bond.     

Radio Tracking of a Fin Whale (Balaenoptera physalus)

A tagged whale of the genus Balaenoptera was intermittently tracked by radio for 27.8 hours over a distance of about 145 kilometers. Data on breathing and movement show that during that time the whale took 58 breaths in 130 minutes and traveled 20 kilometers at more than 9 kilometers per hour. Precise measurements of such parameters and of other features of the life history of great whales, which travel long distances over the high seas, often in groups, are now possible through radio tagging.     

The vaccine adjuvant monophosphoryl lipid A as a TRIF-biased agonist of TLR4

The inflammatory toxicity of lipopolysaccharide (LPS), a component of bacterial cell walls, is driven by the adaptor proteins myeloid differentiation factor 88 (MyD88) and Toll-interleukin 1 receptor domain-containing adapter inducing interferon-beta (TRIF), which together mediate signaling by the endotoxin receptor Toll-like receptor 4 (TLR4). Monophosphoryl lipid A (MPLA) is a low-toxicity derivative of LPS with useful immunostimulatory properties, which is nearing regulatory approval for use as a human vaccine adjuvant. We report here that, in mice, the low toxicity of MPLA's adjuvant function is associated with a bias toward TRIF signaling, which we suggest is likely caused by the active suppression, rather than passive loss, of proinflammatory activity of this LPS derivative. This finding may have important implications for the development of future vaccine adjuvants.     

Interaction of calcitonin and calcitonin gene-related peptide at receptor sites in target tissues

Discrete receptor sites for calcitonin (CT) and calcitonin gene-related peptide (CGRP) were found in the nervous system and in peripheral tissues. Each peptide was capable of cross-reacting with the specific receptor of the other. In contrast to CT receptors, CGRP receptors were not linked to adenylate cyclase. However, CGRP could stimulate adenylate cyclase in CT target tissues apparently by interacting with CT receptors. The relative abilities of CGRP and mammalian CT to inhibit CT binding suggest that CGRP could serve as an endogenous ligand for CT receptors in the central nervous system.     

Sex pheromones and reproductive isolation of the lesser peachtree borer and the peachtree borer

(E,Z)-3,13-octadecadien-1-ol acetate, and (Z,Z)-3,13-octadecadien-1-ol acetate, isolated from the female lesser peachtree borer, Synanthedon pictipes (Grote and Robinson), and the female peachtree borer, Sanninoidea exitiosa (Say), respectively, strongly attract the respective males of these species in field bioassays. These compounds are the largest pheromones isolated thus far from a lepidopterous species. Sanninoidea exitiosa males did not respond to the synthesized (E,Z)-isomer, and low concentrations of it in the synthesized (Z,Z)-isomer did not interfere with their response to the (Z,Z)-isomer. In contrast, even very low concentrations of the (Z,Z)-isomer (1 percent) in the (E,Z)-isomer significantly inhibited the response of Synanthedon pictipes males.