On the structure and chromosome location of the 72- and 92-kDa human type IV collagenase genes.

The 72- and 92-kDa type IV collagenases are members of a group of secreted zinc metalloproteases. Two members of this family, collagenase and stromelysin, have previously been localized to the long arm of chromosome 11. Here we assign both of the two type IV collagenase genes to human chromosome 16. By sequencing, the 72-kDa gene is shown to consist of 13 exons, 3 more than have been reported for the other members of this gene family. The extra exons encode the amino acids of the fibronectin-like domain which has so far been found in only the 72- and 92-kDa type IV collagenase. The evolutionary relationship among the members of this gene family is discussed.     

Correlation of adenosine receptor affinities and cardiovascular activity

Binding affinities of 28 adenosine analogs at A1 adenosine receptors (rat whole brain membranes, [3H]N6-cyclohexyladenosine, CHA), and at A2 adenosine receptors (rat striatal membranes, [3H]NECA) were compared to their EC25 values for decreasing heart rate and increasing coronary flow in the isolated rat heart. Heart rate (an A1 response) correlated with A1 binding affinity (r2 = 0.71, p less than 0.0001) but not with A2 binding affinity (r2 = 0.007, n.s.); conversely, coronary flow (an A2 response) correlated with A2 binding affinity (r2 = 0.83, p less than 0.0001) but not with A1 binding affinity (r2 = 0.05, n.s.). These results confirm that the brain A1 and A2 receptors, studied by binding methods, bear close similarities to their respective counterparts in the heart, studied by means of functional responses.     

Effect of anti-mosquito antibodies on the infectivity of the rodent malaria parasite Plasmodium berghei to Anopheles farauti

The effect of mouse anti-mosquito antibodies, present in the bloodmeal, on the infectivity of Plasmodium berghei Vincke to Anopheles farauti Laveran was investigated. Significantly fewer oocysts developed in mosquitoes feeding on mice immunized with sugar-fed mosquito midgut antigens than in mosquitoes feeding on control mice. Mosquitoes feeding on mice immunized with the midgut antigens derived from sugar-fed mosquitoes also showed reduced mortality and had lower infection rates than those fed on unimmunized mice. Blood-fed midgut antigen was less effective in producing these effects than sugar-fed midgut antigen.     

Human corticotropin releasing hormone gene is located on the long arm of chromosome 8

The chromosomal locus of the human corticotropin releasing hormone (hCRH) gene was assigned to chromosome 8 using Southern blot analysis of human x rodent cell hybrids and was localized to band 8q13 using in situ hybridization to metaphase chromosomes. The absence of secondary hybridization strongly suggests that hypothalamic and placental CRH are transcribed from the same gene.     

Molecular biology of wound-inducible proteinase inhibitors in plants

Abstract. The techniques of molecular biology are being employed to investigate at the gene level the systemically mediated, wound-induced accumulation of two defensive proteinase inhibitor proteins in plant leaves. These techniques have added a new dimension to biochemical and physiological studies already underway to understand the mechanism of induction by wounding. The acquisition of cDNAs from the RNAs coding for the two inhibitors facilitated studies of mRNA synthesis in leaves in response to wounding, and provided probes to obtain wound-inducible proteinase inhibitor genes from tomato ( Lycopersicon esculentum ) and potato (Solarium tuberosum) genomes. Successful transformations of tobacco plants with fused genes, containing the 5' and 3' regions of the inhibitor genes with the open reading frame of the chloramphenicol acelyltransferase ( cat ) gene, have provided a wound-inducible chloramphenicol acetyltransferase (CATase) activity with which to seek cis- and transacting elements that regulate wound-inducibility to help to understand the interaction of cytoplasmic and nuclear components of the intracellular communication systems that activate the proteinase inhibitor genes in response to wounding by insect pests.     

Isolation and characterization of a cDNA that encodes the peptide core of the secretory granule proteoglycan of human promyelocytic leukemia HL-60 cells

A cDNA that encodes the peptide core of the secretory granule proteoglycan of the human promyelocytic leukemic cell line, HL-60, has been isolated and analyzed. When human genomic DNA was digested and probed under conditions of low stringency with a rat cDNA that encodes a Mr = 18,600 serine/glycine-rich proteoglycan peptide core in L2 yolk sac tumor cells (Bourdon, M. A., Oldberg, A., Pierschbacher, M., and Ruoslahti, E. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 1321-1325) and basophilic leukemia-1 cells (Avraham, S., Stevens, R. L., Gartner, M. C., Austen, K. F., Lalley, P. A., and Weis, J. H. (1988) J. Biol. Chem. 263, 7292-7296), a number of DNA fragments were identified. A HL-60 cell-derived cDNA library was therefore screened under conditions of low stringency with the rat probe to identify and isolate a human homologue of this rat proteoglycan peptide core. Analysis of the resulting human cDNA clones indicated that the proteoglycan peptide core that is expressed in HL-60 cells is Mr = 17,600 and contains an 18-amino acid glycosaminoglycan attachment region that consists primarily of alternating serin and glycine. Northern blot analysis of total RNA probed with the human cDNA revealed that the major message for this proteoglycan peptide core in HL-60 cells is approximately 1.3 kilobase pairs in size. When a Southern blot of digested human genomic DNA was probed with the human cDNA, three bands of approximately 6, 9, and 12 kilobase pairs were detected. However, when the Southern blot was probed with the XmnI----3' fragment of this human cDNA, one prominent band was detected, indicating that a single gene encodes this protein in the human. Analysis of the DNA from human/mouse and human/hamster somatic cell hybrids probed with the human cDNA demonstrated that the gene that encodes this molecule resides on human chromosome 10. Because the proteoglycans that are present in the secretory granules of different types of rat and mouse mast cells possess small peptide cores that are rich in serine and glycine, we propose that this HL-60 cell-3 derived cDNA encodes the peptide core of the proteoglycan that is expressed in the secretory granules of this human promyelocytic cell.     

Vitamin D-dependent calcium-binding protein of mouse yolk sac. Biochemical and immunochemical properties and responses to 1,25-dihydroxycholecalciferol

The present studies were performed to further characterize a mouse yolk sac protein which is similar or identical to the vitamin D-dependent intestinal calcium-binding protein (CaBP). Yolk sac protein and purified rat intestinal CaBP displayed full identity upon immunodiffusion (Ouchterlony) using antiserum to the rat intestinal CaBP. Immunoreactive CaBP in yolk sac homogenates eluted from gel permeation columns with the low molecular weight peak of 45Ca2+ binding (Chelex assay), and the electrophoretic mobility of the protein was markedly increased by EDTA. On days 11-13 of gestation, the concentrations of immunoreactive CaBP in yolk sac were 4-5-fold higher than in placenta; by days 16-17, the concentrations in yolk sac and placenta were similar. Incubation of yolk sac with [3H]leucine demonstrated synthesis of immunoprecipitable [3H]CaBP. A single band of 3H-labeled protein was seen on sodium dodecyl sulfate gel electrophoresis of the immunoprecipitate. This protein co-migrated with radioactive placental CaBP with an apparent Mr of 10,050. Addition of 1,25-dihydroxycholecalciferol (calcitriol) to organ culture media with or without serum increased the amount and concentration of CaBP in yolk sac (p less than 0.001) at 48 h. CaBP synthesis in yolk sac appeared to be independent of calcitriol concentrations in the maternal circulation since injection of the hormone into the maternal compartment produced no change in yolk sac CaBP despite increases of maternal intestinal and renal CaBP. These studies demonstrate that yolk sac immunoreactive CaBP is synthesized in yolk sac and has an apparent molecular size and calcium-binding properties characteristic of mammalian vitamin D-dependent calcium-binding proteins. The in vitro response of yolk sac CaBP to calcitriol is the first evidence of a vitamin D effect on the fetal membranes and suggests one function for calcitriol receptors in these tissues.     

Human serum amyloid P component. cDNA isolation, complete sequence of pre-serum amyloid P component, and localization of the gene to chromosome 1

Complementary DNA clones corresponding to the human serum amyloid P component (SAP) were isolated, and the complete nucleotide and derived amino acid sequence of preSAP was determined. PreSAP biosynthesis is directed by a 1.1-kilobase mRNA. Synthesis and postsynthetic processing of preSAP in Xenopus oocytes result in secretion of a protein with mobility similar to native purified SAP when analyzed by sodium dodecyl sulfate gel electrophoresis. The human SAP gene is on chromosome 1, probably closely linked to the gene for C-reactive protein which encodes the related acute phase reactant found in human plasma.     

Chronic exercise and left ventricular structure and function in healthy human subjects

Twelve healthy well-trained participants in a supervised exercise program (mean age, 41.3 yr) were compared with 12 sedentary control subjects (mean age, 38.9 yr) with physical characteristics similar to the exercised group (EG) before training. Resting echocardiograms revealed significantly lower heart rates (HR) in the EG compared with control group (CG) but no evidence for cardiac structural differences between groups. Radionuclide angiograms performed at rest and during two levels of supine cycling (HR targets: 120 and 140 beats X min-1) resulted in increases in background-corrected end-diastolic counts [EDC(bc)] and confirmed use of the Frank-Starling mechanism in the majority of subjects. Mean values (+/- SD) for ejection fraction (EF) and normalized peak systolic ejection rate (PSER) (P greater than 0.05 between groups) were the following. (Formula: see text) The results suggested that fitness training does not induce significant cardiac enlargement as apparent from measurements at rest or important changes in contractile state during exercise. Increases in exercise stroke volume with such training may be the result of an increased end-diastolic volume.