Genotype of Yupik Eskimos with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Summary An A-to-G transition in the second intron was the sole mutation detected in four Yupik Eskimo patients with salt-wasting congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency. Allele-specific hybridization should be an efficient means of performing prenatal diagnosis of the disease in this highly inbred population.     

Phenylketonuria—Experience at One Center in the First Year of Screening in California

One year''s experience with phenylketonuria during the calendar year 1966, the first year for compulsory newborn screening in California, was reviewed. The over-all prevalence rate from reported cases in California during this period was one case per 19,500 persons tested. Fifty-seven persons suspected of having pku were evaluated, and 25 of them were determined to be phenylketonuric. Eleven of the 25 were infants in whom the abnormality was detected through the newborn screening program or because it was detected in a sibling through a screening program. All the newborn phenylketonuric patients were developing normally at the time of last report (although the follow-up periods were short).In nine of the other children, pku was detected because they were retarded. Five retarded children who were diagnosed as phenylketonuric at another clinic were given dietary assistance.Five additional infants had elevated serum phenylalanines but did not have the classic biochemical findings of pku and are being evaluated further. Nine infants with positive screening tests exhibited biochemical and clinical findings consistent with transient tyrosinemia. Eighteen other children were evaluated and found to have no metabolic abnormality.The newborn screening program for pku is of decided benefit in early identification of a group of infants who have a high rate of potentially serious metabolic disease. Early identification permits treatment soon enough to prevent mental retardation. Newly identified patients should be evaluated in a medical setting capable of careful pediatric, biochemical and nutritional surveillance.     

Isolation of High-Frequency Recombining Strains from Escherichia coli Containing the V Colicinogenic Factor

The isolation and characterization of high-frequency recombining strains from different Escherichia coli host cells containing either the F factor or the Col V factor are described. The strains (with one exception) formed from three of the V⁺ parents showed the same origin and polarity of transfer (xyl-arg-pro-trp-his-mal). The Hfr strains formed from the one remaining V⁺ and the F⁺ host cells showed a greater variety in their points of origin. In addition, several Hfr strains isolated from V⁺ parents lost the ability to produce colicin V. F_v⁺ segregants of these were isolated, and the F_v factors appeared to retain their preferential site for Hfr formation, but they lacked other propertes controlled by the Col V factor. Chromosomal integration of episomes and its relation to the fertility of F⁺ and V⁺ strains are discussed. Production of colicin V appeared to be uninfluenced by the state of the Col V factor within the cell.     

Intracellular aminopeptidases inStreptomyces lividans 66

Summary We have investigated the aminopeptidase activities present inStreptomyces lividans strains. The majority of these activities proved to be intracellular with multiple active species. Two aminopeptidase P genes were identified to be responsible for the ability to hydrolyze amino terminal peptide bonds adjacent to proline residues. Two other broad spectrum aminopeptidases were found to display homology at both the DNA and protein levels. One showed significant homology to PepN proteins, particularly around the putative zinc-binding residues which are important for catalysis. The second broad spectrum activity was not analyzed in detail but showed a different spectrum of substrate specificity to that of PepN.     

Characterization and immunocytochemical demonstration of glucocorticoid receptor using antisera specific to transformed receptor

Cytosolic and nuclear forms of the glucocorticoid receptor were characterized using immunochemical techniques. Antibodies were raised in rabbits to an M_r 58,000 fragment of the transformed (DNA-binding) glucocorticoid receptor purified from rat liver cytosol by DNA-cellulose chromatography and polyacrylamide gel electrophoresis. Antibodies reacted with the transformed receptor form in a radioimmunoassay for glucocorticoid receptor. Western blot analysis of antibody reactivity revealed a single M_r 185,000 receptor form in rat liver cytosol but a smaller M_r 85,000 form in nucleosol, indicating the M_r 85,000 form is the transformed receptor. Furthermore, western blot analysis indicates that the M_r 185,000 receptor undergoes proteolysis during receptor purification and in vitro transformation processes by generating immunochemically similar proteins of smaller molecular weights. An identical M_r 185,000 glucocorticoid receptor was detected in cytosols of four rat tissues; liver, brain, adrenal medulla, and thymus. The glucocorticoid receptor was localized to the cytoplasm and nucleus of rat adrenal medulla cells by immunohistochemistry, demonstrating the existence in vivo of the transformed receptor and translocation of the receptor from cytoplasm to nucleus.     

Enhanced virulence effect of K1 polysaccharide in neonatal rats challenged withE. coli

Purified K1 polysaccharide enhanced the virulence of non-K1Escherichia coli species when given by orogastric feeding to neonatal rats. Neonatal rats developedE. coli bacteremia when K1 polysaccharide was given concomitantly with non-K1E. coli, whereasE. coli bacteremia did not develop when non-K1E. coli was given alone.E. coli K1 species did cause bacteremia and meningitis when fed to neonatal rats. The mechanism by which k1 polysaccharide enhances virulence can be studied with this model of bacteremia development in neonatal rats.     

Evolution of α2-macroglobulin. The structure of a protein homologous with human α2-macroglobulin from plaice (Pleuronectes platessa L.) plasma

The plaice (Pleuronectes platessa L.) papain-binding protein previously demonstrated to be homologous with human alpha(2)-macroglobulin, and designated plaice alpha(2)-macroglobulin homologue or alphaMh, was shown to be a glycoprotein of s(20,w) 11.86S. In polyacrylamide-gel pore-limit electrophoresis under non-denaturing conditions plaice alphaMh migrated to the same position as half-molecules of human alpha(2)-macroglobulin, and treatment with methylamine or a proteinase caused no change in its electrophoretic properties. Either denaturation in urea (4m) or mild reduction by dithiothreitol (1mm) partially dissociated plaice alphaMh into half-molecules. Denaturation with reduction further dissociated the protein into quarter-subunits. In sodium dodecyl sulphate/polyacrylamide-gel electrophoresis under reducing conditions plaice alphaMh dissociated into subunits of M(r) 105000 (I) and 90000 (II). Approximately equal amounts of each subunit were formed, and peptide ;mapping' showed subunits I and II to be distinct polypeptide chains. Under alkaline denaturing conditions, a proportion of the I chains of alphaMh were cleaved into fragments of M(r) about 60000 and 40000. This cleavage was favoured by reducing conditions and prevented by prior inactivation of the alphaMh with methylamine. [(14)C]Methylamine allowed to react with alphaMh became covalently linked to subunit I. These properties suggested the existence of an autolytic site on subunit I analogous to the autolytic site of human alpha(2)-macroglobulin. Reaction of alphaMh with a proteinase resulted in cleavage of a fragment of M(r) 10000-15000 from subunit I. A proportion of the proteinase molecules trapped by alphaMh became covalently linked to the inhibitor. A scheme is proposed for the evolution of human alpha(2)-macroglobulin and plaice alphaMh from a common ancestral protein, which may also have been an ancestor of complement components C3 and C4.     

Reversed-phase liquid chromatographic investigation of UV-absorbing low-molecular-weight compounds in saliva

The reversed-phase mode of high-performance liquid chromatography was used to determine the intra- and inter-individual levels of UV-absorbing low-molecular-weight compounds in saliva. Many of the compounds known to occur in serum were also found in saliva; however, concentrations in saliva are lower. Both the intra- and inter-individual levels of these compounds vary significantly; in most cases, the inter-individual variance is 2–3 times the intra-individual variance.

Caffeine and its metabolites in saliva are also reported. A greater number of metabolites were found in the saliva of habitual coffee drinkers. After caffeine was administered orally, paraxanthine, theobromine, theophylline, 1-methylxanthine, and 1-methyluric acid were found in the saliva of an individual who did not drink coffee regularly. In this subject, the serum half-life for caffeine was 3.49 h and the saliva half-life was 3.27 h. The half-life of caffeine in an habitual coffee drinker who had refrained from caffeine products for four days was 4.39 h.