The androgen-dependent rat prostate protein,probasin, is a heparin-binding protein that co-purifies with heparin-binding growth factor-1

Summary Rat prostate extracts contain an abundant 20–22 kilodalton heparin-binding protein with near identical chromatographic properties, but only 0.2–1% of the mitogenic activity, of bovine brain heparin-binding growth factor-1 (acidic fibroblast growth factor). Amino terminal amino acid sequence (met-met-thr-asp-lys-asn-leu-lys-lys-lys-ile-glu-gly-asn-trp-arg-thr-val-tyr-leu-ala-ala-ser-?-val-glu-lys-ile-asn-glu-gly-ser-pro) and immunochemical analysis revealed that the protein is identical to the androgen-dependent protein “probasin”. This work was supported in part by NCI grant CA37589 (W. L. M., J. W. C.) and the Medical Research Council of Canada (R. J. M.).     

Effect of aortic balloon inflation on ventilation and brain stem blood flow in piglets

Increases in brain stem blood flow (BBF) during hypoxia may decrease tissue PCO2/[H+], causing minute ventilation (VE) to decrease. To determine whether an increase in BBF, isolated from changes in arterial PO2 and PCO2, can affect respiration, we obstructed the thoracic aorta with a balloon in 31 intact and 24 peripherally chemobarodenervated, anesthetized, spontaneously breathing newborn piglets. Continuous measurements of cardiorespiratory variables were made before and during 2 min of aortic obstruction. Radiolabeled microspheres were used to measure BBF before and approximately 30 s after balloon inflation in eight intact and five denervated animals. After balloon inflation, there was a rapid increase in mean blood pressure in both the intact and denervated animals, followed within 10 s by a decrease in tidal volume and VE. In the intact animals, the decrease in VE after acute hypertension can be ascribed to a baroreceptor-mediated reflex. After peripheral chemobarodenervation, however, acute hypertension continued to produce a decrease in VE, which cannot be explained by baroreceptor stimulation. In these denervated animals, aortic balloon inflation was associated with an increase in BBF (13.1 +/- 2.7%; P less than 0.05). We speculate that the increase in BBF during hypoxia may contribute to the decrease in ventilation observed after carotid body denervation.     

GENETIC RELATEDNESS OF TWO POPULATIONS OF THE SOUTHERN ELEPHANT SEAL, MIROUNGA LEONINA

Blood samples from southern elephant seals ( Mirounga leonina ) from Heard and Macquarie Islands were surveyed electrophoretically for protein variation. Thirty proteins encoded by a minimum of 35 loci were screened, four of which were found to be polymorphic. Statistically significant differences in allele frequencies were found between the two populations at three loci. Heterozygosity estimates for the Heard and Macquarie island populations were 0.034 ± 0.020 (mean ± standard error) and O.029 ± 0.017 respectively, with a Nei distance of 0.007. The findings suggest that the two populations may have diverged genetically and very limited gene flow exists between the islands, a finding consistent with limited information from mark-recapture studies.     

Gustatory sensitivity of the herbivore Tilapia zillii to amino acids

The gustatory sensitivity of the herbivorous fish Tilapia zillii was investigated using electrophysiological techniques. Integrated responses from facial taste nerves were recorded during stimulation by l l amino acids. All compounds proved to be effective stimuli. The relative stimulatory efficacy (RSE) determined at 1 × 10 ⁻³ m indicated that stimuli can be organized into three groups on the basis of similarity of efficacy. Effects of pH which altered the RSE of some amino acids are documented. Amino acid RSE differed to some extent from those of previously studied carnivorous fish. There was concordance between the composition of preferred food, effective feeding stimuli and the peripheral receptor responses. These observations support the hypothesis that peripheral chemosensitivity might serve as a mechanism of feeding specialization in some fish.     

Characterization of envelope proteins of alcelaphine herpesvirus 1.

Alcelaphine herpesvirus 1 is a gammaherpesvirus which causes malignant catarrhal fever, an acute lymphoproliferative disorder of cattle and other susceptible Bovidae, which is almost invariably fatal. A preliminary analysis of proteins induced by the virus indicated that as many as six glycoproteins and one nonglycosylated molecule might be present in the virus envelope. Monoclonal antibodies selected for recognition of virion envelope proteins included two that recognized a complex of infected cell proteins, designated the gp115 complex, and neutralized virus infectivity in the absence of complement. The gp115 complex consisted of five glycoproteins of 115, 110, 105, 78, and 48 kilodaltons (kDa), and all except the 48-kDa species reacted with antibody in Western blots (immunoblots). Pulse-chase experiments analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing and nonreducing conditions suggested that the 110-kDa protein was the precursor molecule which was processed by addition of sugars to 115 kDa. The 115-kDa protein was cleaved to form a disulfide-linked heterodimer of 78 and 48 kDa, which was the mature form of the molecule incorporated into the virion envelope. The glycoprotein contained N-linked sugars, but little or no O-linked sugar was present. The relative abundance of the mature protein and its ability to induce neutralizing antibodies suggest that it will prove useful to studies aimed at elucidating the biology and pathogenesis of alcelaphine herpesvirus 1.     

A novel and remarkably thermostable ferredoxin from the hyperthermophilic archaebacterium Pyrococcus furiosus.

The archaebacterium Pyrococcus furiosus is a strict anaerobe that grows optimally at 100 degrees C by a fermentative-type metabolism in which H2 and CO2 are the only detectable products. A ferredoxin, which functions as the electron donor to the hydrogenase of this organism was purified under anaerobic reducing conditions. It had a molecular weight of approximately 12,000 and contained 8 iron atoms and 8 cysteine residues/mol but lacked histidine or arginine residues. Reduction and oxidation of the ferredoxin each required 2 electrons/mol, which is consistent with the presence of two [4Fe-4S] clusters. The reduced protein gave rise to a broad rhombic electronic paramagnetic resonance spectrum, with gz = 2.10, gy = 1.86, gx = 1.80, and a midpoint potential of -345 mV (at pH 8). However, this spectrum represented a minor species, since it quantitated to only approximately 0.3 spins/mol. P. furiosus ferredoxin is therefore distinct from other ferredoxins in that the bulk of its iron is not present as iron-sulfur clusters with an S = 1/2 ground state. The apoferredoxin was reconstituted with iron and sulfide to give a protein that was indistinguishable from the native ferredoxin by its iron content and electron paramagnetic resonance properties, which showed that the novel iron-sulfur clusters were not artifacts of purification. The reduced ferredoxin also functioned as an electron donor for H2 evolution catalyzed by the hydrogenase of the mesophilic eubacterium Clostridium pasteurianum. P. furiosus ferredoxin was resistant to denaturation by sodium dodecyl sulfate (20%, wt/vol) and was remarkably thermostable. Its UV-visible absorption spectrum and electron carrier activity to P. furiosus hydrogenase were unaffected by a 12-h incubation of 95 degrees C.