Genetic and evolutionary relationships among Asian Macaques

Published gene frequency data, checked for consistency of allele definitions across laboratories and for comparability of geographically identical samples, were pooled into a data set containing frequencies at nine loci for each of 20 populations that encompassed 10 macaque species. Genetic distances were calculated by the methods of Kidd and Cavalli-Sforza (1974). These distances were used to construct phylogenetic trees and to evaluate the relationships between divergence times and effective population sizes. Inter-and intraspecific genetic distances and the groupings defined by phenetic tree analyses support Fooden’s (1976) classification of the genus Macacainto four species groups. A paleozoogeographical model of Asia including the known times of major sea-level changes allows us to explain Macacainto four species groups. A paleozoogeographical model of Asia including the known times of major sea-level changes allows us to explain qualitatively the inferred evolutionary relationships among macaque species. Many assumptions are required in order to estimate the variables necessary in the quantitative prediction of genetic differences for a comparison between any two populations. Examination of those assumptions demonstrates the need for more accurate genetic as well as paleozoogeographic information. An erratum to this article is available at .     

Comparison of methods for estimating Erwinia carotovora numbers on potato tubers

Two methods for estimation of the numbers of Erwinia carotovora on potato tubers were compared using 17 naturally infected stocks. The 'wash' method estimates the surface count, whereas the 'peel' method is based on a subcuticular count. A correlation of 0.79 was obtained. Comparisons between methods were also made using a bactericide, Myacide As, and on stocks during chitting. Erwinia carotovora counts were reduced in treated tubers with the 'wash' method, but not with the 'peel' method.     

Aeromedical transport: its hidden problems.

Air transport can move patients safely and rapidly over long distances. However, changes in altitude can have disastrous effects because diminished ambient air pressure may allow gases in closed spaces and tissues to expand rapidly. Even pressurized commercial aircraft do not maintain sea-level pressure: cabin pressures equal to those at yp to 8000 ft may be experienced, diminishing oxygen tension in proportion. Air transport is absolutely contraindicated for patients with untreated pneumothorax, gas gangrene, or air trapped in the cranium and those who have recently undergone abdominal surgery. Special considerations including a planned low-altitude flight are warrented for patients who are anemic, in respiratory or cardiac distress, or immobilized in casts, or who have been engaged in underwater diving immediately before the flight.     

Effects of pressure on uptake and release of calcium by brain synaptosomes

Uptake of radioactive calcium from guinea pig brain fractions enriched in synaptosomes could be significantly and reproducibly decreased by exposure to high pressure. Calcium efflux from preloaded synaptosomes was unaffected by pressure exposure. It was hypothesized that the development of pressure-induced encephalopathy may be related to an effect of pressure on the central nervous system calcium transport system.     

Effects of phorbol dibutyrate on M currents and M current inhibition in bullfrog sympathetic neurons

1. Effects of bath-applied phorbol dibutyrate (PDBu) on M currents (IM) and on the inhibition of IM by muscarine and luteinizing hormone-releasing hormone (LHRH) were recorded in voltage-clamped bullfrog lumbar sympathetic ganglion cells. 2. PDBu (0.1-30 microM) produced a slowly developing, irreversible and partial (less than or equal to 60%) inhibition of IM. This effect was not replicated by 4-alpha-phorbol or by vehicle. 3. After treatment with PDBu, residual IM showed a reduced sensitivity to inhibition by muscarine or LHRH but not by Ba2+. The reduced response to muscarine appeared to result from a 10-fold shift in the concentration dependence for inhibition. 4. PDBu did not clearly reproduce the ability of muscarine to inhibit the slow, Ca-activated K current IAHP or to increase the leak conductance at hyperpolarized potentials. The latter effect of muscarine was enhanced, rather than inhibited, by PDBu. 5. IM and IAHP were not inhibited by 1 mM dibutyryl cyclic AMP or by 20 microM forskolin. 6. It is concluded that activation of protein kinase C, but not protein kinase A, partly replicates the effect of muscarine on frog sympathetic neurons.     

Intracellular mitochondrial membrane potential as an indicator of hepatocyte energy metabolism: further evidence for thermodynamic control of metabolism

The lipophilic triphenylmethylphosphonium cation (TPMP+) has been employed to measure delta psi m, the electrical potential across the inner membrane of the mitochondria of intact hepatocytes. The present studies have examined the validity of this technique in hepatocytes exposed to graded concentrations of inhibitors of mitochondrial energy transduction. Under these conditions, TPMP+ uptake allows a reliable measure of delta psi m in intracellular mitochondria, provided that the ratio [TPMP+]i/[TPMP+]e is greater than 50:1 and that at the end of the incubation more than 80% of the hepatocytes exclude Trypan blue. Hepatocytes, staining with Trypan blue, incubated in the presence of Ca2+, do not concentrate TPMP+. The relationships between delta psi m and two other indicators of cellular energy state, delta GPc and Eh, or between delta psi m and J0, were examined in hepatocytes from fasted rats by titration with graded concentrations of inhibitors of mitochondrial energy transduction. Linear relationships were generally observed between delta psi m and delta GPc, Eh or J0 over the delta psi m range of 120-160 mV, except in the presence of carboxyatractyloside or oligomycin, where delta psi m remained constant. Both the magnitude and the direction of the slope of the observed relationships depended upon the nature of the inhibitor. Hepatocytes from fasted rats synthesized glucose from lactate or fructose, and urea from ammonia, at rates which were generally linear functions of the magnitude of delta psi m, except in the presence of oligomycin or carboxyatractyloside. Linear relationships were also observed between delta psi m and the rate of formation of lactate in cells incubated with fructose and in hepatocytes from fed rats. The linear property of these force-flow relationships is taken as evidence for the operation of thermodynamic regulatory mechanisms within hepatocytes.