The isolation and identification of multiple forms of the neutrophil granule peptides from human leukemic cells

HP-1 is a 30-residue cysteine- and arginine-rich peptide of the human neutrophil primary granule and is the most abundant human representative of the family of peptides variously called defensins and corticostatins. Peptides belonging to this family have many biological activities including the non-oxidative destruction of ingested microorganisms, the inhibition of adrenocorticotropin-stimulated synthesis of glucocorticoids, monocyte chemotaxis, the non-cytolytic inhibition of [3H]thymidine incorporation in HL-60 promyelocyte-like cells and the stimulation of nifedipine-sensitive calcium channels. Using a combination of reversed-phase and size-exclusion high performance liquid chromatography and an HP-1 radio-immunoassay, three immunoreactive peptides were detected and isolated from the promyelocyte-like cell line, HL-60, and from leukocytes of patients with chronic myelogenous and chronic lymphocytic leukemias. One of these peptides was HP-1 itself. A second was identified by gas-phase Edman microsequencing as an amino-terminally extended fragment of the HP-1 precursor which we call HP1-56. The third is likely to arise from enzymatic cleavage of the precursor at a dibasic site. Of the leukemic cells the greatest amount of HP1-56 relative to HP-1 was found in cells from a patient in myeloblastic crisis but overall the richest source of HP1-56 relative to HP-1 was found to be in fetal lung tissue. HP1-56 is difficult to detect in normal peripheral neutrophils and its presence in cells that are actively biosynthesizing primary granule components such as HL-60 may make it useful for studying the biosynthesis of granule polypeptides, their ontogeny, and possibly as a marker protein for leukemic diseases.     

Molecular genetic analysis of the Escherichia coli phoP locus.

We have cloned the Escherichia coli phoP gene, a member of the family of environmentally responsive two-component systems, and found its deduced amino acid sequence to be 93% identical to that of the Salmonella typhimurium homolog, which encodes a major virulence regulator necessary for intramacrophage survival and resistance to cationic peptides of phagocytic cells. The phoP gene was mapped to kilobase 1202 on the Kohara map (25-min region) of the E. coli genome (Y. Kohara, K. Akiyama, and K. Isono, Cell 50:495-508, 1987) and found to be transcribed in a counterclockwise direction. Both E. coli and S. typhimurium phoP mutants were more sensitive than their isogenic wild-type strains to the frog-derived antibacterial peptide magainin 2, suggesting a role for PhoP in the response to various stresses in both enteric species.     

Does a cytoplasmic bridge connect the CNS axon with the inner loop of myelin?

Sarah Luse (1959) reported over 30 years ago on the presence of a bridge connecting the axon to the myelin sheath in the central nervous system (CNS). This notion has not been accepted in the literature. Wolman (1992) found that the progress of demyelination in some viral diseases affecting the CNS fits the concept of Luse, as the process occurred primarily along the major dense line of myelin, which is in continuity with the cytoplasm of the oligodendroglial cell. Injection of Lucifer yellow (LY) and horseradish peroxidase (HRP) into the vitreous of guinea pigs, with and without iontophoresis, resulted in labeling of the nerve axons and myelin. Labeling of myelin by HRP occurred along the major dense line which indicated that a transient or permanent cytoplasmic bridge connects axons and myelin in the optic nerve.     

Catabolism of naphthalene and salicylate byPseudomonas fluorescens

Analysis of spent naphthalene growth media ofPseudomonas fluorescens by GC-MS revealed the presence of salicylate. Gentisate 1,2-dioxygenase and pyrocatechol 1,2-dioxygenase were induced by growth on naphthalene, whereas only pyrocatechol 1,2-dioxygenase was induced during growth on salicylate. These results suggest the existence of alternative degradative routes of salicylate,via gentisate and pyrocatechol, which are involved in the catabolism of naphthalene.     

A locus for familial hypertrophic cardiomyopathy is closely linked to the cardiac myosin heavy chain genes, CRI-L436, and CRI-L329 on chromosome 14 at q11-q12

We report that a gene responsible for familial hypertrophic cardiomyopathy (HC) is closely linked to the cardiac alpha and beta myosin heavy chain (MHC) genes on chromosome 14q11. We have recently shown that probe CRI-L436, derived from the anonymous DNA locus D14S26, detects a polymorphic restriction fragment that segregates with familial HC in affected members of a large Canadian family. Using chromosomal in situ hybridization, we have mapped CRI-L436 to chromosome 14 at q11-q12. Because the cardiac MHC genes also map to this chromosomal band, we have determined the genetic distances between the cardiac beta MHC gene, D14S26, and the familial HC locus. Data presented here show that these three loci are linked within 5 centimorgans on chromosome 14 at q11-q12. The possibility that defects in either the cardiac alpha or beta MHC genes are responsible for familial HC is discussed.     

Endogenous respiration and regulation in a primitive marine fungus

The relationship between the respiration and the presence and utilization of endogenous and exogenous substrates was studied in the non-filamentous obligately marine fungus Thraustochytrium aureum. Using isotopic and manometric methods, it was shown that almost all exogenous glucose is assimilated, whilst almost all the oxygen consumption in the presence of exogenous glucose was due to oxidation of endogenous reserves. In contrast, exogenous glutamate, which cannot serve as the sole carbon source for growth, inhibits respiration of endogenous materials, and is itself rapidly oxidized. The uncoupler 2,4-dinitrophenol stimulates the oxidation of endogenous reserves without affecting the uptake and use of exogenous glucose. These data strongly support the idea of physiologic compartmentation in this organism.     

Effects of chronic administration of somatostatin on rat exocrine pancreas

We studied the effects of somatostatin on synthesis of pancreatic DNA, RNA and protein and on pancreatic weight and contents of DNA, protein, amylase and chymotrypsinogen in rats. In short term synthesis studies, rats were injected with 100 micrograms . kg-1 somatostatin or 0.15 M NaCl (control) at times 0, 8 and 16 h. Eight rats from each treatment group were killed 2, 4, 8, 12, 16, 20 and 24 h after beginning treatment. Incorporation rates in vivo of [3H]thymidine into DNA, [3H]uridine into RNA and [14C]phenylalanine into total protein were significantly depressed by somatostatin. In long term studies, four groups of 12 rats were injected every 8 h for 5 days with 0.15 M NaCl or 11, 33 or 100 micrograms . kg-1 somatostatin. Body weight was unaffected but pancreatic contents of DNA, protein and enzymes were significantly decreased by somatostatin. Administration of somatostatin inhibits DNA, RNA and protein synthesis in exocrine pancreas with resulting decreases in DNA and enzyme contents.     

Hormonally sensitive cyclic AMP phosphodiesterase in liver cells. An ecto-enzyme

Ecto-cyclic AMP phosphodiesterase activity was determined from freshly isolated and cultured liver cells. The cells were capable of hydrolyzing cyclic AMP in the medium. The ecto-phosphodiesterase represents a low Km phosphodiesterase which was activated by physiological concentrations of insulin. The product, 5'-AMP, was recovered in the medium and not with the cells. The enzyme was inhibited with aminophylline and trypsin. The ecto-phosphodiesterase activity was proportional to cell number, and total phosphodiesterase activity increased 5- to 10-fold when the cells were ruptured. About one-third of the ecto-phosphodiesterase activity from freshly isolated liver was due to phosphodiesterase in the medium. No phosphodiesterase was in the medium of cultured liver cells.