Linkage analysis and allelic imbalance in human breast cancer kindreds using microsatellite markers from the short arm of chromosome 3

Eight Icelandic breast cancer kindreds were subjected to linkage analyses with respect to 28 microsatellite loci dispersed along the short arm of chromosome 3. Breast tumors derived from these kindreds were concurrently scored for allelic imbalance with ten of the markers. Linkage to most markers could be excluded on the basis of negative LOD scores and haplotype analyses, although some moderately positive LOD scores resulted. A high frequency of imbalance in the familial tumors was seen with two of the markers in comparison with results obtained from sporadic material. The highest frequency (68%) of imbalance was detected with the marker D3S1217, which is located on 3p14.2-p14.1. Imbalance at the D3S1211 locus, which is more telomeric (3p24.2-p22), was not significantly elevated in the familial tumors. We suggest that the genetic defect responsible for breast cancer susceptibility in these families either promotes instability in the 3p14.2-p14.1 region or enhances the selective advantage of such changes.     

Internally quenched fluorogenic protease substrates: Solid-phase synthesis and fluorescence spectroscopy of peptides containing ortho-aminobenzoyl/dinitrophenyl groups as donor-acceptor pairs

Summary A general procedure, using the commonly employed solid-phase peptide synthesis methodology for obtaining internally quenched fluorogenic peptides with ortho-aminobenzoyl/dinitrophenyl groups as donor-acceptor pairs, is presented. The essential feature of this procedure is the synthesis of an N -Boc or-Fmoc derivative of glutamic acid with the -carboxyl group bound to N-(2,4-dinitrophenyl)-ethylenediamine (EDDnp), which provides the quencher moiety attached to the C-terminus of the substrate. The fluorescent donor group, ortho-aminobenzoic acid (Abz), is incorporated into the resin-bound peptide in the last coupling cycle. Depending on the resin type used, Abz-peptidyl-Gln-EDDnp or Abz-peptidyl-Glu-EDDnp is obtained. Using the procedure described above, substrates for human renin and tissue kallikreins were synthesised. Spectrofluorimetric measurements of Abz bound to the -amino group of proline showed that strong quenching of Abz fluorescence occurs in the absence of any acceptor group.     

Expression of platelet membrane glycoproteins and alpha-granule proteins by a human erythroleukemia cell line (HEL)

We demonstrate that HEL, a human erythroleukemic cell line, has numerous megakaryocytic markers which were markedly enhanced following the addition of the inducers dimethyl sulfoxide or 12-O-tetradecanoylphorbol-13-acetate to the culture medium. Ultrastructural and cytochemical studies showed: (i) the presence of organelles morphologically resembling the platelet alpha-granules; and (ii) a peroxidase activity with the same characteristics as that specifically found in platelets. The platelet alpha-granule proteins (von Willebrand factor, platelet factor-4 and beta-thromboglobulin) were immunologically detected in the HEL cell cytoplasm and their amounts increased after induction. Of particular interest was the presence of platelet membrane proteins. A monoclonal antibody specific for glycoprotein Ib bound to HEL cells. Platelet membrane glycoproteins IIb and IIIa were identified on intact cells using specific antibodies in a binding assay or in cell lysates using either crossed immunoelectrophoresis or an immunoblotting procedure following SDS-polyacrylamide gel electrophoresis. Most HEL cells also expressed the platelet alloantigen PIA1. All of the platelet membrane proteins were present in higher amounts after induction. Glycophorin A, specific for the erythroid lineage, was also detected on HEL cells. Thus, while confirming the presence of erythroid markers, our studies provide evidence that the HEL cell line also expresses platelet antigens. As such, HEL cells represent a unique system with which to study the biosynthesis of platelet-specific proteins and glycoproteins.     

Mutant hemoglobin stability depends upon location and nature of single point mutation

The temperature dependence of the rates of heme release from the beta subunits of methemoglobin A and 5 beta mutant methemoglobins has been determined. The rates were largest for two hemoglobins with mutations distal to heme, previously known to be unstable. The other 3 mutants also released heme faster than A. These hemoglobins, with single point mutations at the alpha 1/beta 2 interface, were previously thought to be stable. The low reported yields of the 5 mutant proteins covaries with the relative rates of heme release from the met species.     

The C4 and Slp genes of the complement region of the murine H-2 major histocompatibility complex

Recent analyses, at the protein and DNA levels of structure, of the murine complement components C4 and the closely related sex-limited protein, Slp have led to new insights into the H-2/S region-linked C4 and Slp genes and their products. The primary products are 200 000 Da precursors which are cleaved, intracellularly and extracellularly, into the the mature alpha-beta-gamma-subunit molecules of plasma. Precursor order of subunits is beta-alpha-gamma; a complementary DNA clone spanning the alpha-gamma junction has been extensively analysed. The C-terminal of the alpha-chain is of particular interest because of post-secretion processing which differentiates 'secreted' and 'plasma' forms of C4, both apparently functional, and because allelic variants of C4 and the Slp protein, which differ substantially in molecular masses, owe their differences principally to different levels of glycosylation of the alpha-chain. Allelic variations in rate of C4 synthesis (C4-high compared with C4-low) have been analysed in cultures of hepatocytes and macrophages. Three distinct modes of genetic regulation of the expression of the Slp protein have been identified.     

The biosynthetic pathway of new polyamines in Caldariella acidophila

A spontaneous mutant of Escherichia coli (strain AB2847), selected for resistance to the aminoglycoside antibiotic neamine, shows severe restriction of amber suppressors in vivo. Ribosomes isolated from the mutant exhibit only low misreading in vitro in the presence of the antibiotic. Genetic and biochemical analyses indicate that the neamine-resistant phenotype is the result of two distinct mutations. The first, res3128, appears to affect the gene (strA) coding for the ribosomal protein S12. Although it leads to a restrictive phenotype it does not, however, confer resistance to streptomycin. The second mutation, X3128, is located between the sirA and AROB loci and is lethal when segregated from the res3128 mutation. It may affect the ribosome at the level of a post-translational modification.     

ON THE MECHANISM OF ELECTROSHOCK-INDUCED INHIBITION OF PROTEIN SYNTHESIS IN RABBIT CEREBRAL CORTEX

Abstract— The mechanism of electroshock (ES)-induced inhibition of protein synthesis in rabbit cerebral cortex has been investigated by using a cell-free system. The protein biosynthetic activity of the post-mitochondrial supernatant (PMS) obtained from the cerebral cortex of ES-treated animals was found to be markedly lower than in controls (C). This inhibition was accompanied by a decrease of polysomes and an increase of monomers. In addition, a relative increase in light polysomes was evident at short intervals after ES treatment. No difference was found in the total soluble activity and in the activity of the elongation factors and ribonuclease present in the cell sap of C and ES animals. The biosynthetic activity of ES-total. free and membrane-bound ribosomes was approx 45% lower than that of the corresponding C fractions: polysome/monomer ratios were similarly reduced. The total content of cortical ribosomes was not affected by ES. Following ES treatment there was no change in the ribo-somal ability to elongate, terminate and release polypeptide chains, nor a decrease in the polysomal content of poly(A)-containing mRNA. These data strongly suggest that the ES-induced inhibition of protein synthesis results from a defect in the initiation process. The possible mechanisms mediating this defect have been discussed.     

The action of cyclic somatostatin on hypoglycemia due to prolonged fasting in normal animals]

The authors have examined the action of cyclic Somatostatin on blood glucose levels in normal rats and in rats starved for 36 and 50 hours. The infusion of 0,235 gamma/min. of Somatostatin for thirty minutes in the normals induced a slight increase in blood glucose levels that was statistically non significative. Under the same condition, the cyclic Somatostatin increased, in a statistically significant way, the levels of plasma glucose in both starved groups of rats.     

Banding patterns of the chromosomes ofCercopithecus neglectus: Comparison withMiopithecus talapoin andErythrocebus patas

The G, Q, and C bands and the location of the nucleolar organizing regions (NORs) of the chromosomes of two male Cercopithecus neglectusare described. The diploid number of the species is 2n =62. Comparison with the karyotypes of Miopithecus talapoin (2n =54), and Erythrocebus patas (2n =54)showed the presence of total banding homeology for only 10 chromosome pairs.     

Serological analysis and pathogenic potentials of Wangiella dermatitidis isolated from bats

Methods for the preparation of antigens from clinically isolated cultures of Aspergillus were standardized. Sera from 25 suspected cases of pulmonary aspergillosis were tested against antigens prepared by us, from 4 strains of A. fumigatus and one strain of A. flavus, using the Ouchterlony double diffusion and immunoelectrophoretic techniques.Of the 25 sera tested, 18 reacted positively with antigens of A. fumigatus, one with A. flavus and 2 with both these species. Antigens of two non-pathogenic Aspergilli included in the study failed to react with any of the sera. Our antigen preparations gave more numerous as well as sharper precipitin lines than the commercial Bencard antigens which were used for comparison. Moreover, mycelial antigens from 48 to 96 h old cultures revealed precipitin lines comparable to that of the routine, 4 week old culture filtrate antigens, thus suggesting that the incubation period for obtaining antigens could be cut down considerably.Memoir No. 323 from the Centre of Advanced Study in Botany.Deceased