The nonstructural component of the Abelson murine leukemia virus polyprotein P120 is encoded by newly acquired genetic sequences.

The Abelson leukemia virus (AbLV) polyprotein P120 is compared to translational products representing the entire Moloney murine leukemia virus (MuLV) genome on the basis of [35S]methionine tryptic peptide composition. Three methionine-containing tryptic peptides present in Moloney Pr65gag are each shown to be present in both Pr75gag and in Pr180gag-pol. Of these, one peptide, corresponding to Moloney MuLV p12, but neither of two p30-specific peptides are present in AbLV P120. Among the 12 remaining methionine-containing peptides present in AbLV P120, many, if not all, are unique to AbLV P120 and not shared by either Moloney MuLV Pr180gag-pol or Pr82gag.     

Habitat selection and territorial defense behaviors in juvenile cortez angelfish,Pomacanthus zonipectus (gill)

Scuba diving observations in the Gulf of California (Mexico) on juvenile Cortez angelfishes, Pomacanthus zonipectus (Gill), indicate that these fish select and defend territories centered about a rock crevice. By day, they make brief feeding excursions, venturing even over open sandy areas near the rocks. They are substrate feeders, and will remove ectoparasites from other fishes, even attempting to clean human divers. At night they remain in their rock crevices. Laboratory experiments, conducted to quantify habitat-selection and territorial-defense behaviors in juvenile P. zonipectus, revealed that they spend 75% of their time during the day near rocks and 25% over sand in a divided experimental tank. The frequency of attacks on a mirror image increased as the mirror was moved closer to the rock crevice which was the territorial focus.     

Thermoregulatory behavior of the pink shrimp Penaeus duorarom Burkenroad

Measurements of Balanus balanoides (L.) distribution at Dipper Harbour, New Brunswick, Canada, indicate as individuals per unit area increase, external morphology changes. This trend is reflected largely by height increase. Directional aspect of substrate effects numbers of barnacles as well as their shapes.     

Isolation of human nerve growth factor from placental tissue

Nerve growth factor (NGF) has been isolated from human placental tissue. Using the chicken embryo dorsal root ganglia assay, we determined levels of NGF activity for the amnion, placental cotyledons, cord serum, fetal serum, and maternal serum. The highest levels of NGF activity were measured in placental cotyledons. After homogenization and centrifugation of the placental cotyledons, the supernatant was sequentially chromatographed, at neutral pH, on Sephadex G-100, DEAE-11, and Sephadex G-150. A high-molecular-weight protein fraction (150,000), which contained all the biological activity, was isolated in this fashion. Analytical isoelectric focusing of this fraction revealed a basic protein component (pI 9.5) of the high-molecular-weight species. Assays for NGF activity of all protein components separated by analytical isoelectric focusing showed that NGF activity was associated only with the basic protein component. Correspondingly, preparative isoelectric focusing of the high-molecular-weight species yielded a basic protein with very high biological activity (1–3 ng per biological unit) that was immunochemically active against rabbit IgG made against mouse -NGF.To whom reprint requests should be addressed.     

Indole reactions of mast cells and enterochromaffin cells related to fixations with and without aldehydes

Summary Survey of a considerable number of rat, mouse and hog tissues which presented large numbers of mast cells in preparations stained with toluidine blue and other metachromatic or basic dyes at low pH levels, revealed numbers of oval bodies of about the same size as mast cells which reacted weakly or even moderately to the postcoupled benzylidene indole reaction. The numbers of these were always less than that of mast cells in toluidine blue sections of the same blocks. They never occurred in clusters of perhaps 15–20 in a single high power field, as mast cells often do. Smooth and especially striated muscle which often formed the background tissue where most mast cells are found with metachromatic stains, regularly present indole reactions due to protein tryptophan. This is usually equal to or stronger than that in the supposed mast cells.Indole reactive bodies whose morphology suggests mast cells are also present in similar numbers in formaldehyde and glutaraldehyde fixed tissue as well as with aldehyde free fixations. Glutaraldehyde and formaldehyde are known to inhibit the benzylidene reaction of 5-HT in vitro (30 min for glutaraldehyde, 3 h for formaldehyde) (Lillie, 1977). This action was avoided in mercury and lead heavy metal fixations and in acetone, Carnoy, chloroform methanol and similar fixations.The mast cell-like bodies are best explained as tangential or oblique sections of individual muscle fibers. We have described the same phenomenon with the ferric ferricyanide (Golodetz-Unna, 1909) reaction (Lillie et al., 1978a), and the PCB reaction is that of tryptophan in these muscle cell sections.In contrast to the DMAB type reaction failure acid diazosafranin successfully demonstrated mast cells with both aldehyde and aldehyde free fixations. This reaction has been shown to occur with 5-HT and 5-HTP (Lillie et al., 1973).     

Evidence that latent collagenases are enzyme-inhibitor complexes.

Specific collagenase from the culture media of various rabbit tissues and cells exists in active and latent forms. Latent collagenase is most effectively activated with 4-aminophenylmercuric acetate, a thiol-blocking reagent, strongly suggesting that latent forms are enzyme-inhibitor complexes. A collagenase inhibitor from bone cultures, which may be closely related to the inhibitor of such latent enzyme complexes, was partially characterized.     

Radar-based studies of the migratory flight of grasshoppers in the middle Niger area of Mali.

Some grasshopper species are pests of subsistence agriculture in the Sahelian zone of West Africa. Formulation of effective control strategies against these pests requires some knowledge of their migratory ability. In this paper a study is described in which radar was used to observe aspects of the nocturnal migratory behaviour of grasshoppers in the middle Niger delta. Mass take-off at dusk, layering and common orientation were regularly observed. Layering appeared to be related to air temperature. Mean orientation was often downwind but at other times crosswind headings occurred which added to the southerly component of the insects' displacement. Probable source areas of insects overflying the radar were identified by calculations of the insects' back-trajectories.     

Fast reactions in carbon monoxide binding to heme proteins.

Using fast flash photolysis, we have measured the binding of CO to carboxymethylated cytochrome c and to heme c octapeptide as a function of temperature (5 degrees-350 degreesK) over an extended time range (100 ns(-1) ks). Experiments used a microsecond dye laser (lambda = 540 nm), and a mode-locked frequency-doubled Nd-glass laser (lambda = 530 nm). At low temperatures (5 degrees-120 degreesK) the rebinding exhibits two components. The slower component (I) is nonexponential in time and has an optical spectrum corresponding to rebiding from an S = 2, CO-free deoxy state. The fast component (I*) is exponential in time with a lifetime shorter than 10 mus and an optical spectrum different from the slow component. In myoglobin and the separated alpha and beta chains of hemoglobin, only process I is visible. The optical absorption spectrum of I* and its time dependence suggest that it may correspond to recombination from an excited state in which the iron has not yet moved out of the heme plane. The temperature dependences of both processes have been measured. Both occur via quantum mechanical tunneling at the lowest temperatures and via over-the-barrier motion at higher temperatures.