Circulatory galanin levels increase severalfold with intense orthostatic challenge in healthy humans.

The purpose of this study was to test the hypothesis that plasma galanin concentration (pGal) is regularly increased in healthy humans with extensive orthostatic stress. Twenty-six test persons (14 men, 12 women) were brought to an orthostatic end point via a progressive cardiovascular stress (PCS) protocol consisting of 70 degrees head-up tilt plus increasing levels of lower body negative pressure until either hemodynamically defined presyncope or other signs of orthostatic intolerance occurred (nausea, clammy skin, excessive sweating, pallor of the skin). We further tested for possible gender, gravitational, and muscular training influences on plasma pGal responses: PCS was applied before and after 3 wk of daily vertical acceleration exposure training on a Human Powered Centrifuge. Test persons were randomly assigned to active (with bicycle work) or passive (without work) groups (seven men, six women in each group). Resting pGal was 26+/-3 pg/ml in men and 39+/-15 pg/ml in women (not significant); women had higher galanin responses (4.9-fold increase) than men (3.5-fold, P=0.017) to PCS exposure. Overall, PCS increased pGal to 186+/-5 pg/ml (P=0.0003), without significant differences between presyncope vs. orthostatic intolerance, pre- vs. postcentrifuge, or active vs. passive gravitational training. Increases in pGal were poorly related to synchronous elevations in plasma vasopressin. We conclude that galanin is regularly increased in healthy humans under conditions of presyncopal orthostatic stress, the response being independent of gravity training but larger in women than in men.     

Genetic architecture of growth and early life‐history transitions in anadromous and derived freshwater populations of steelhead

Heritabilities of growth, precocious maturation and smolting were measured in 75 families of juvenile steelhead or rainbow trout Oncorhynchus mykiss , progeny of within and between line matings (crosses) of wild, anadromous steelhead and wild, resident (lake) rainbow trout originally derived from the same anadromous stock 70 years earlier. The tagged yearling progeny were combined by line in common freshwater rearing containers and graded into three categories: mature, smolt or rearing (undifferentiated) at age 2 years. Heritabilities of precocious male maturity, smolting and growth were moderate to high, and the genetic correlation between growth and smolting was low. Smolting and precocious male maturity were highly variable among families within lines and significantly different between lines. Each of the four lines produced significant numbers of smolts at age two. Smolting and maturation were negatively genetically correlated, which may explain the persistence of smolting in the lake population despite strong selection against lake smolts; balancing selection on male maturation age may help to maintain variation for smolting. The high heritability of smolting, coupled with the inability of smolts that leave the lake to return to it indicates that the genetic potential for smolting can lie dormant or be maintained through a dynamic interaction between smolting and early maturation for decades despite complete selection against the phenotype. The results have significant implications for the preservation of threatened anadromous stocks in fresh water and the inclusion of resident fish of formerly anadromous populations, currently trapped behind long‐standing barriers to migration, as one component of the same population.     

The salt relations of Dunaliella

Dunaliella tertiolecta (marine) and D. viridis (halophilic) were each trained by serial transfer to growth at salt concentrations previously regarded as the other's domain. D. viridis then had a salt optimum at 1.0–1.5 M sodium chloride whereas that for D. tertiolecta was less than 0–2 M. Nevertheless D. tertiolecta grew faster than the halophil at all salt concentrations up to 3.5 M, the highest at which they were compared.Both species accumulate glycerol, which is necessary for growth at elevated salinities and which responds in its content to water activity (a _w ) rather than specifically to salt concentration. Variation in glycerol content is a metabolic process which occurs in the dark from accumulated starch as well as photosynthetically. Regulation of glycerol content by a _w does not require protein synthesis. The NADP-specific glycerol dehydrogenase of each of the algae is likely to be directly involved in the regulation of glycerol content. Kinetic studies, together with those described in an earlier publication, show that the enzyme has regulatory properties, and that both glycerol and dihydroxyacetone act as effectors as well as reactants. A mechanism of the reaction is tentatively proposed.     

Aflatoxin localization by the enzyme-linked immunocytochemical technique.

Visualization of aflatoxin deposits within Aspergillus parasiticus ATCC 15517 hyphae was made possible by using an enzyme-linked immunocytochemical technique.     

Duplication,concerted evolution and purifying selection drive the evolution of mosquito vitellogenin genes

Background  

Mosquito vitellogenin (Vtg) genes belong to a small multiple gene family that encodes the major yolk protein precursors required for egg production. Multiple Vtg genes have been cloned and characterized from several mosquito species, but their origin and molecular evolution are poorly understood.     

Effect of polyhydric alcohols on kinetic parameters of enzymes

The effect of glycerol and other polyhydric compounds on the kinetic parameters of sixteen enzymes has been investigated. Substantial changes in K_m and turnover rate were observed. Kinetic values obtained depended on pH as well as on the specific polyhydric compound added and its concentration. No pattern in direction or extent of change in kinetic constants was evident.     

DISTRIBUTION OF FOUR POTENTIAL TRANSMITTER AMINO ACIDS IN MONKEY RETINA

Discrete layers from frozen dried sections of Rhesus monkey retina were analyzed for each of four amino acids. Peak levels of glycine were found near the border of the inner nuclear and inner reticular layers, and were high throughout these two layers. The levels were less than 50% of the peak in the adjacent ganglion cells and outer reticular layers and fell to very low levels elsewhere. GABA was much more sharply restricted to the inner reticular layer and fell off on both sides to levels of 10% or less of the peak in the fiber and photoreceptor cell layers. Glutamate and aspartate were highest in the ganglion cell layer. On a lipid-free dry weight basis the peak aspartate level was about twice that of brain. Moderately high levels of both aspartate and glutamate were found in the inner reticular and fiber layers. Elsewhere the levels ranged from 20 to 50% of the peak, and both amino acids were relatively low in optic nerve. The amino acid distributions are compatible with a transmitter function for GABA in amacrine cells and for glycine in horizontal and amacrine cells. Glutamate and aspartate may be especially high in Müller fibers, ganglion cells or both.