Differential phosphorylation of multiple sites in protein 4.1 and protein 4.9 by phorbol ester-activated and cyclic AMP-dependent protein kinases

The phosphorylation of the membrane skeleton components protein 4.1 and protein 4.9 in intact erythrocytes is shown to increase in the presence of either 1 microM 12-O-tetradecanoyl phorbol 13-acetate or 2 mM dibutyryl cAMP. The phosphorylation induced by these protein kinase activators is compared by two-dimensional tryptic peptide mapping. In both proteins, the pattern of peptides phosphorylated in the presence of 12-O-tetradecanoyl phorbol 13-acetate differs from the pattern of peptides phosphorylated in the presence of dibutyryl cAMP. The relative locations of the phosphorylated sites on protein 4.1 have been determined using limited proteolysis by alpha-chymotrypsin.     

Physiological adaptations of an under-ice population of Pseudocalanus in Barrow Strait (N.W.T) to increasing food supply in spring

Summary Zooplankton and water samples were collected at weekly intervals between April 25 and May 30, 1986 in Barrow Strait, N.W.T. (Canadian Arctic Archipelago). In tows from 0–30 m, the zooplankton community (>202 m) was dominated by Pseudocalanus. The population was apparently growing and developing as shown by an increase in the proportion of adults (stage VI) and decreases in the proportion of stages III, IV, and V as the season progressed. Respiration and excretion rates of the Pseudocalanus populations were probably linked, there being an immediate increase in excretion rate, accompanying an increase in feeding rate when chlorophyll concentrations increased, which was followed by a smaller increase in respiration rate after a time lag. Hence, there was a large decrease in the ON ratio. Increased metabolism coincided with changes in the population structure, as did protease and bodily protein, but could not be clearly linked to dietary acclimation. Only laminarinase activity could be statistically related to an identifiable fraction of potential nutritional value in the water, particulate soluble carbohydrate, but neither showed overall seasonal change.     

Molecular cloning of a cDNA for human pregnancy-specific beta 1-glycoprotein:homology with human carcinoembryonic antigen and related proteins

Human pregnancy-specific beta 1-glycoprotein (SP1) plays an essential role in normal pregnancy. It is also a well-characterized oncodevelopmental antigen, expressed aberrantly by all trophoblastic tumors and some other malignant cell types. Here we report the identification of a human placental cDNA encoding the SP1 polypeptide sequence. The coding sequence shows 95% identity at the nucleotide level with a distinct, recently published SP1 cDNA sequence (PSG16). Unexpectedly, the sequence is also highly homologous to the published sequence of human carcinoembryonic antigen (CEA). SP1, CEA and CEA-related nonspecific cross-reacting species thus belong to a group of closely related though antigenically diverse tumor-associated glycoproteins. Comparison of the deduced amino acid sequence of the SP1 cDNA with that of CEA provides insight into the modular nature of these related proteins. This may have implications for the genomic organization and evolution of the CEA gene family.     

Maternal age at last birth in Egypt

To assess the effects of women's education, residence, and marital experience on their age at the birth of their last child, a proportional hazards regression model was applied to 1980 Egyptian Fertility Survey (EFS) data. The detailed data include the date of birth of each child for every women interviewed, and the woman's date of birth and age at interview. Age at last birth was examined by regression analysis on birth history and socioeconomic information. 4 hypotheses were tested: women who are well educated have a greater probability of ending childbearing earlier than women with less education; women in rural areas have a higher probability of having their last child at older ages than urban women; marital disruption without remarriage lowers the probability of older maternal age at last birth; and marital disruption with remarriage increases the probability that a woman stops reproducing at an older age. The overall chi-square indicates a significant regression. All coefficients were significant, except the coefficient for women with intact 1st marriages. Women with more education had a greater probability of ending childbearing earlier than women with less education. Rural women tended to have their last children at ages significantly older than overall age at last birth. Current residence in urban areas had the opposite effect. The coefficient for those with intact 1st marriages was insignificant, meaning that the mean age at last birth for this group of women was not much different from the overall mean. Remarried women tended to end childbearing at ages significantly older than the overall average age at last birth, suggesting that these women tended to have children by their new husbands. Those with dissolved 1st marriages who had not remarried had a higher probability of ending childbearing earlier than did older women. Marriage age and final parity had highly significant negative coefficients; as marriage age and number of children born increased, so did the "survival" time or the age at last birth. Results from the hazards model indicate that the effects were as anticipated. The median age at last birth for the total sample of women aged 45-49 was 45-49 years. The median age at last birth was about 2 years older for rural compared to urban women. Illiterate women had the oldest median age at last birth of the education groups. There was little differences between median ages at last birth for women with intact 1st marriages and those whose 1st unions were dissolved and who had remarried. The median age at last birth increased with final parity.     

Direct determination of homovanillic acid release from the human brain, an indicator of central dopaminergic activity

The plasma concentration of the dopamine (DA) metabolite, homovanillic acid (HVA), is used as an indicator of central nervous system dopaminergic activity. Using percutaneously inserted catheters we were able to obtain blood samples simultaneously from the right and left internal jugular veins. Veno-arterial HVA plasma concentration differences combined with adjusted organ plasma flows were used, according to the Fick Principle, to determine the HVA overflow from the brain. The HVA overflow from the liver was also measured. HVA overflow from the brain represented 12% of the total body HVA production. A similar amount was released from the liver, illustrating the limited validity of peripheral plasma HVA measurements as an indicator of central dopaminergic activity. HVA release from the human brain displayed a degree of asymmetry, the overflow into the left internal jugular vein being 36% greater than that into the right. Cerebral venous blood flow scans indicated that cortical cerebral regions drained preferentially into the right internal jugular; by inference the higher HVA overflow on the left originated from dopamine-rich subcortical brain areas. Since HVA in plasma may arise from the metabolism of DA existing either as a neurotransmitter or a norepinephrine (NE) precursor we measured the internal jugular vein plasma concentrations of NE, and its metabolite dihydroxyphenylglycol (DHPG), to determine whether they displayed a similar pattern of release to HVA. The overflow of both NE and DHPG into the right internal jugular vein was approximately double that on the left. Since the overflow of HVA did not parallel that of NE and DHPG it may be inferred that the origin of much of the subcortically produced HVA is from dopaminergic neurons and not from the metabolism of precursor DA in noradrenergic neurones or cerebrovascular sympathetic nerves.     

Correlation of immune assays with protection in rainbow trout, Salmo gairdneri, immersed in Vibrio bacterins

One hundred kg of Rainbow trout, Salmo gairdneri, weighing 80–100g each were immersed in a formalized, bivalent vaccine of Vibrio anguiliárum (VA) and Vibrio ordalii (VO), at a1/10 dilution for 30s at 10°C. The protection levels achieved at 8 and 10 weeks post vaccination were assessed by intraperitoneal challenge with 10⁵ live V. anguillarnm or V. ordalii. No decline in protection due to antigen depletion was found between batches throughout the procedure. The protection conferred by one component of the vaccine was slightly better than the other (80% against VO and 42 % against VA). A number of measures of immunity were monitored before and after challenge. These included serum and mucus antibody litres, bactericidal effects of serum and mucus and phagocytosis by peritoneal exudate cells. Serum antibody was present (peak litre of-log₂ 3.25 for VO, and 4.4 for VA) but had declined to background levels by the time of challenge, whereas bactericidal effects and phagocytosis rate of 40% were not increased by vaccination. The most likely immune mechanism responsible for the observed protection was discussed and suggested to be a cellular mechanism where serum antibody acts as an opsonin to increase phagocytosis.     

Relationship between the level of estrone sulfate in the plasma and the number of fetuses during pregnancy in the gilt

Estrone sulfate was measured in the plasma of pregnant and nonpregnant gilts between Days 10 and 32 after estrus. Estrone sulfate was found to rise sharply in pregnant gilts beginning at Day 18 and to decline at Day 30 to Day 32. Estrone levels were not related to litter size. The level of estrone sulfate on Days 20, 22, 24 and 26 was significantly correlated with litter size at slaughter on Day 32. Reduction of the number of live fetuses by crushing them in utero at Day 40 or between Days 30 to 60 did not cause a subsequent reduction in the level of estrone sulfate, whereas reduction at Day 24 did cause a decline in estrone sulfate. The level of estrone sulfate in plasma of gilts at 20 to 28 days after mating was higher in pregnant than in nonpregnant gilts. The relative level of estrone sulfate would enable one to estimate litter size at Days 20 to 28 days but not later. Because of the limitations of the assay in exact quantitation of the levels of estrone sulfate, the results can only be considered qualitative.     

Reassociation of Purified Lipopolysaccharide and Phospholipid of the Bacterial Cell Envelope: Electron Microscopic and Monolayer Studies

Phosphatidyl ethanolamine and lipopolysaccharide were extracted and purified from the cell envelope fractions of Escherichia coli and Salmonella typhimurium. The two components were studied separately and after recombination, by use of electron microscopy and monolayer techniques, and by measuring their ability to participate in the enzyme-catalyzed uridine diphosphate-galactose:lipopolysaccharide alpha, 3 galactosyl transferase reaction, which requires a lipopolysaccharide-phospholipid complex as substrate. Electron microscopy of purified lipopolysaccharide showed a uniform population of hollow spheres, with each sphere bounded by a continuous leaflet. The diameter of the spheres was approximately 500 to 1,000 A, and the thickness of the enveloping leaflet was approximately 30 A. Phosphatidyl ethanolamine showed a regular lamellar structure. When lipopolysaccharide and phosphatidyl ethanolamine were mixed under conditions of heating and slow-cooling, the leaflet of the lipopolysaccharide spheroids appeared to extend directly into the phosphatidyl ethanolamine structure, with continuity between the two leaflets. Various stages of penetration were seen. At high concentrations of lipopolysaccharide, there were disruptive changes in phosphatidyl ethanolamine leaflets similar to those seen when saponin acts on cholesterol-lecithin leaflets. Monolayer experiments indicated that lipopolysaccharide penetrated a monomolecular film of phosphatidyl ethanolamine at an air-water interface, as revealed by an increase in surface pressure. The results indicate that a common leaflet structure containing lipopolysaccharide and phosphatidyl ethanolamine may be formed in vitro, and suggest that a similar leaflet may exist in the intact bacterial cell envelope.