Temporal and spatial trends in allozyme frequencies in house fly populations,Musca domestica L.

Summary Allelic and genotypic frequencies were sampled from a single age class of the common house fly, Musca domestica L., at five farms on six dates from July 6 to October 12, 1982. Allozymes at six loci were resolved with vertical polyacrylamide gel electrophoresis. No consistent departures from random mating were detected. No consistent linkage disequilibrium was observed. Allele frequencies at the farms changed in independent and unpredictable ways. Gene frequencies at the five farms were initially divergent, converged in midsummer, and then progressively diverged. The divergence occured in mid-August when fly populations were large. Variation in gene frequencies at adjacent farms accounted for a large proportion of the variance in allele frequencies among all farms. These observations are consistent with the hypothesis that allele frequencies in young adult flies reflected the habitat in which they matured as larvae.Journal Paper No. 11718 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project No. 2411     

Kinetic model of a multienzyme system of blood prostanoid synthesis. I. Mechanism of stabilization of thromboxane and prostacyclin levels

A kinetic scheme of the prostacyclin-thromboxane system has been evolved on the basis of the authors experimental data and the results described elsewhere. The kinetic behavior of the model has been analysed with the aid of computer technology by varying the following parameters: phospholipase activities, free arachidonic acid exchange rates between platelets and endothelium, PGH-synthetase biosynthesis rates, velocities of arachidonic acid pathways other than the cyclooxygenase ones. It has been demonstrated that the biological system is capable of sustaining prostacyclin and thromboxane concentrations at steady fixed levels within a wide range of kinetic parameters.     

The molecular and metabolic program by which white adipocytes adapt to cool physiologic temperatures

Although visceral adipocytes located within the body’s central core are maintained at approximately 37°C, adipocytes within bone marrow, subcutaneous, and dermal depots are found primarily within the peripheral shell and generally exist at cooler temperatures. Responses of brown and beige/brite adipocytes to cold stress are well studied; however, comparatively little is known about mechanisms by which white adipocytes adapt to temperatures below 37°C. Here, we report that adaptation of cultured adipocytes to 31°C, the temperature at which distal marrow adipose tissues and subcutaneous adipose tissues often reside, increases anabolic and catabolic lipid metabolism, and elevates oxygen consumption. Cool adipocytes rely less on glucose and more on pyruvate, glutamine, and, especially, fatty acids as energy sources. Exposure of cultured adipocytes and gluteal white adipose tissue (WAT) to cool temperatures activates a shared program of gene expression. Cool temperatures induce stearoyl-CoA desaturase-1 (SCD1) expression and monounsaturated lipid levels in cultured adipocytes and distal bone marrow adipose tissues (BMATs), and SCD1 activity is required for acquisition of maximal oxygen consumption at 31°C.

Adipocytes in bone marrow, subcutaneous and dermal sites generally exist at temperatures below 37°C. This study identifies the molecular and metabolic program that adapts white adipocytes to these cooler environments.     

Apparatus for the automated measurement of the responses of humans to odorants

An automated system for the measurement of the psychophysicaland physiological responses of humans to odorant stimulationof the nose and eyes is described. All aspects of the generationand production of odor stimuli, the recording of physiologicaland psychophysical responses of the subjects and the storageof data are managed by an Apple He computer. Both the nasaland ocular olfactometers are based on electronic mass flow controllerswhich are used to control the ratios of volume flow rates ofclean and odorant-saturated air. The output of each olfactometeris measured by a photo-ionization detector. Odor stimuli aredelivered to custom-fitted face masks, that allow separate stimulationof the nose and eyes, through Teflon (rtm) flow valves. A videocamera records the responses of the eyes and a pneumotachograph,in combination with a pressure transducer, records changes inrespiratory behavior. An electronic mouse is used to enter thesubject's psychophysical responses directly into the computer.The advantages of this methodology and its current and potentialapplications are discussed.