Isolation of enamelinlike proteins from blue shark (Prionace glauca) enameloid

A sequential dissociative extraction scheme was used to extract proteins from developing Blue Shark enameloid. The first extraction solution (4 M guanidine HC1) solubilized the polypeptides, mainly collagenous, not closely associated with the hydroxyapatite. The next extraction solution (4 M guanidine HC1, 0.5 M ethylenediaminetetraacedic acid (EDTA] solubilized the proteins more closely associated with the tooth mineral component. After extraction, the proteins were separated and isolated with gel electrophoresis. Protein molecular weights were determined and selected proteins were isolated for amino acid composition analysis. The two proteins isolated were tested for mammalian enamel protein antigenic determinants by a "Dot" immunobinding assay. The isolated proteins were enamelinlike by extraction criteria and amino acid composition. Further, the two proteins share antigenic determinants with mammalian enamel proteins.     

Transposon donor plasmids, based on ColIb-P9, for use in Pseudomonas putida and a variety of other gram negative bacteria

Summary The properties of pLG221, a derivative of the ColIb plasmid carrying the transposon Tn5 are described. This plasmid can be used to introduce Tn5 by conjugation from Escherichia coli into a variety of Gram negative bacteria outside the host range for maintenance of ColIb. Plasmid pLG221, and a similar plasmid pLG223 carrying Tn10 may be of general utility as vectors for transposon-mediated mutagenesis in a variety of Gram negative bacteria.     

On the low viscosity blood of two cold water,marine sculpins

Summary The viscosities of blood from shorthorn sculpin (Myoxocephalus scorpius), longhorn sculpin (Myoxocephalus octodecemspinosus) and winter flounder (Pseudopleuronectes americanus) were compared using a cone-plate viscometer. Both species of sculpin were almost identical with respect to blood and plasma viscosity at the temperatures (0 and 15°C) and shear rates (2.3–90/s) examined. In contrast, the viscosities of winter flounder blood and plasma were considerably greater than those observed in the sculpins. This difference in blood viscosity between the shorthorn sculpin and the winter flounder persisted over the hematocrit range of 0 to 40% red blood cells. The viscosity of the plasma and the interactions between plasma proteins and red blood cells appeared to be the major reasons for the relatively high viscosity of the flounder blood. Although a proportion of the flounder blood viscosity was attributable to fibrinogen, other plasma proteins also appeared to play a significant role. The relatively low blood viscosity of the sculpin species may confer a circulatory advantage during periods of low water temperatures.     

Hematology of three deep-sea fishes: a reflection of low metabolic rates

Blood was collected from three species of fish, Antimora rostrata (Moridae), Lycodes esmarkii (Zoarcidae), Macrurus berglax (Macrouridae), caught at depths ranging from 280 to 2300 m. Hemoglobin concentrations were low in all three species, ranging from 4.4 to 5.4 g/100 ml. Mean erythrocyte volumes were relatively large, and ranged from 277 micron3 in M. berglax to 672 micron3 in A. rostrata. Blood oxygen dissociation curves were hyperbolic, with relatively low Hill constants (0.95-1.26). Mean P50 values ranged from 10 mmHg in M. berglax to 28 mmHg in L. esmarkii. It is concluded that the hematology and oxygen-binding characteristics of the blood of these three deep-sea fish reflects adaptations to low metabolic rates and low general activity habits.     

Effect of breath-hold time on DLCO(SB) in patients with airway obstruction

The single-breath diffusing capacity of the lung for CO [DLCO(SB)] is considered a measure of the conductance of CO across the alveolar-capillary membrane and its binding with hemoglobin. Although incomplete mixing of inspired gas with alveolar gas could theoretically influence overall diffusion, conventional calculations of DLCO(SB) spuriously overestimate DLCO(SB) during short breath-holding periods when incomplete mixing of gas within the lung might have the greatest effect. Using the three-equation method to calculate DLCO(SB) which analytically accounts for changes in breath-hold time, we found that DLCO(SB) did not change with breath-hold time in control subjects but increased with increasing breath-hold time in both patients with asthma and patients with emphysema. The increase in DLCO(SB) with increasing breath-hold time correlated with the phase III slope of the single-breath N2 washout curve. We suggest that in patients with ventilation maldistribution, DLCO(SB) may be decreased for the shorter breath-hold maneuvers because overall diffusion is limited by the reduced transport of CO from the inspired gas through the alveolar gas prior to alveolar-capillary gas exchange.     

The immunocytochemical demonstration of Toxoplasma antigen in the brains of congenitally infected mice

The peroxidase anti-peroxidase immunocytochemical staining method was used to identify Toxoplasma antigen in paraffin embedded sections of the brains of 22 mice congenitally infected with the parasite. Intact Toxoplasma tissue cysts were readily demonstrated in the brain in all cases. In 4 of the 22 infected mice there was evidence of rupture of the cyst wall and/or presence of extra-cystic Toxoplasma antigen. Further support for the extra-cystic location of Toxoplasma antigen was obtained by electron microscopy of reprocessed tissue which revealed endozoites in the area immediately surrounding a ruptured cyst. The possible implications of these findings in relation to the pathogenesis of congenital toxoplasmic meningo-encephalitis are discussed.     

The effect of ACTH on the blood clearance rate of aldosterone, cortisol, 17 alpha-hydroxyprogesterone and 17 alpha, 20 alpha-dihydroxy-4-pregnen-3-one in the sheep

The blood clearance rate (BCR) of aldosterone, cortisol, 17 alpha-hydroxyprogesterone (17 alpha OHP) and 17 alpha, 20 alpha-dihydroxy-4-pregnen-3-one (17 alpha 20 alpha OHP) has been measured in conscious sheep prior to and after 5 or 6 days ACTH treatment. ACTH increased the BCR of cortisol but did not change the BCR of the other three steroids. 17 alpha OHP had a BCR greater than liver blood flow suggesting extra-hepatic metabolism. In vivo conversion of 17 alpha OHP to 17 alpha 20 alpha OHP by ovine red cells has been shown to be a significant site of this metabolism. It is suggested that this conversion of 17 alpha OHP to 17 alpha 20 alpha OHP may be important in the expression of the "hypertensionogenic" effect of 17 alpha OHP.     

Fatty acid composition of the lipids of Puffinus tenuirostris (Temminck) in relation to its diet

The fatty acid composition of lipids isolated from the depot fat, stomach contents, and proventricular oil of adult and chick Puffinus tenuirostris (Temminck) has been analysed. The diet of both adults and chicks is almost exclusively derived from the euphausiid Nyctiphanes australis Sars, and an attempt was made to determine whether dietary lipid affects the composition of depot fat, and whether individual fatty acids in the stomachs and proventricular oil can be used as markers for the origin of the diet. An apparent selectivity in the deposition of fatty acids in the fat depots can be explained by the conversion of fatty alcohols, derived from the euphausiid wax ester, into fatty acids of equivalent chain length and unsaturation. Hexadecadienoic acid appeared to be the only possible marker fatty acid from the euphausiid, but wide variations in its level limits its usefulness as a reliable index of the diet of Puffinus tenuirostris.