Demonstration of high opioid-like activity in isolated peptides from wheat gluten hydrolysates

Because of a possible relationship between schizophrenia and celiac disease, a condition in some individuals who are sensitive to wheat gluten proteins in the diet, there has been interest in observations that peptides derived from wheat gluten proteins exhibit opioid-like activity in in vitro tests. To determine the origin of the peptides exhibiting opioid activity, wheat proteins were fractionated by size (gel filtration), by charge differences (ion exchange chromatography) and by differences in hydrophobicity (reversed-phase HPLC). These fractions were hydrolyzed by pepsin or pepsin and trypsin and the resulting peptides separated by gel filtration chromatography. The separated peptides were tested for opioid-like activity by competitive binding to opioid receptor sites in rat brain tissue in the presence of tritium-labeled dihydromorphine. The peptides showed considerable differences in activity; while some peptides exhibited no activity, 0.5 mg of the most active peptides were equivalent to 1 nM of morphine in the binding assay. The most active peptides were derived from the gliadin fraction of the gluten complex.     

Effects of forskolin and cholera toxin on cyclic AMP release in a neurotensin-secreting rat C-cell line

The effects of forskolin and cholera toxin on the regulation of cAMP release were studied in a neurotensin-secreting rat C-cell line. The interaction of these agents with norepinephrine, a potent neurotensin secretagogue, was also investigated. Forskolin stimulated cAMP release 10(2)-10(3) fold while it increased neurotensin release 2-3 fold. Cholera toxin caused a 10(2)-10(3) fold increase in cAMP release and had no effect on neurotensin release. We conclude that the 44-2 C-cells provide a new model for studying the regulation of the concomitant (via forskolin) or independent (via cholera toxin) secretion of cyclic AMP and/or neurotensin.     

Isolation and complete nucleotide sequence of the gene for bovine parathyroid hormone

The structure of the bovine parathyroid hormone (PTH) gene has been analyzed by Southern blot hybridization of genomic DNA and by nucleotide sequence analysis of a cloned PTH gene. In the Southern analysis, several restriction enzymes produced single fragments that hybridized to PTH cDNA suggesting that there is a single bovine PTH gene. The restriction map of the cloned gene is the same as that determined by Southern blot analysis of bovine DNA. The sequence of 3154 bp of the cloned gene has been determined including 510 bp and 139 bp in the 5' and 3' flanking regions, respectively. The gene contains two introns which separate three exons that code primarily for: (i) the 5' untranslated region, (ii) the pre-sequence of preProPTH, and (iii) PTH and the 3' untranslated region. The gene contains 68% A + T and unusually long stretches of 100- to 150-bp sequences containing alternating A and T nucleotides in the 5' flanking region and intron A. The 5' flanking region contains two TATA sequences, both of which appear to be functional as determined by S1 nuclease mapping. Compared to the rat and human genes, the locations of the introns are identical but the sizes differ. Comparable human and bovine sequences in the flanking regions and introns are about 80% homologous.     

Rat and human embryo and post-natal sera contain a potent endogenous competitor of estrogen-rat alpha-fetoprotein interactions

A highly active inhibitor of the binding of estrone and estradiol-17β to rat alpha-fetoprotein is demonstrated for the first time in embryo, immature and adult rat sera as well as in fetal and adult human sera. The competitive character and the narrow specificity of this inhibition effect is shown. The major compound responsible for this activity is isolated by successive column Sephadex LH₂₀ and thin layer chromatography : it is characterized as a nonpolar, nonphenolic, dialysable and thermostable substance, unreactive towards anti-estrone and anti-estradiol-17β anti-bodies. The possible biological role of an endogenous non-estrogen ligand of rodent fetoproteins is discussed.     

Second-harmonic generation in monolayers of hemicyanine dyes at the air/water interface: Observation of chemical degradation

In situ studies of second-harmonic generation (SHG) in monolayers of pure hemicyanine dyes and their mixtures with arachidic acid at the air/water interface were performed. The studies revealed an unexpected chemical instability of the hemicyanine dyes involving a cleavage of the stilbene double bond when deposited onto the water surface. This reaction occurred especially rapidly in the presence of the arachidic acid. Dilution with arachidic acid did not lead to a significant enhancement of the harmonic intensity.     

Role in hemolysis of the interaction of tellurium compounds with glutathione

We have shown that tellurite and tellurate require the interaction with reduced glutathione (GSH) to hemolyze human erythrocytes. The study of the nature of this interaction is the main object of this paper. The degree of hemolysis was determined by the method of Angelone. The addition of extracellular 1 mM GSH or cysteine increased the rate of hemolysis. Concanavalin A (0.3 mg/mL) and/or 4 mg/mL adenosine did not affect the hemolysis by 0.1 mM tellurite. One tenth to 1 mM 4-acetamido-4′-isothiocyanostilbene-2,2′-disulfonate (SITS) inhibited this hemolysis by 60–100%. Millimolar GSH released this inhibition. Incubation of 0.1 mM tellurite with 1 mM GSH for 90 min at 37°C, produced a hemolytic agent when prepared and tested under nitrogen, but one that was not active when prepared in air. The hemolysis byp-hydroxymercuribenzoate orp-hydroxymercuriphenylsulfonate did not involve GSH. Scanning electron micrographs showed a sphero-echinocyte transformation, in the pre-hemolytic stage, with all the agents tested. The rate of penetration of tellurite plays a role in determining the rate of hemolysis, as shown by the effect of SITS. The release by GSH of the inhibition by SITS poses questions concerning the site of action and cell membrane penetration of the hemolytic agent. Telluride or some intermediate in the interaction of GSH with tellurite is the actual hemolytic agent.     

Electrokinetic study of the reactions of peritoneal macrophages and eosinophils with IgG immune complexes

Electrophoretic light scattering (laser Doppler electrophoresis) has been employed to study the effects of guinea pig IgG immune complexes on the electrophoretic mobility distributions of guinea pig resident peritoneal cells. The resident population of cells is composed of macrophages (approximately 75%) and eosinophils (approximately 25%). These cells were separated according to the well-established method of Boyum. Populations of resident macrophages, eosinophils, and the unfractionated samples were incubated with soluble immune complexes, antigen alone, or antibody alone. The mean mobility of the resident macrophages decreased approximately 60% when incubated in the presence of immune complexes, although no effect could be discerned in the presence of antigen or antibody alone. The width of the resulting macrophage mobility distribution was larger than that of the control distributions, with a broad shoulder on the high-mobility side, indicating a heterogeneous response of the macrophages to the immune complexes. Eosinophils react in two distinct fashions. One population of eosinophils is present near the control experiments. The second population reacts in a manner very similar to that of macrophages. This suggest that at least two populations of eosinophils are present in the unstimulated guinea pig peritoneal cavity. Results that are intermediate between these two cases are found when unfractionated samples are studied.     

Separation of two HMM-S1 species from white muscle myosin

Heavy meromyosin subfragment 1 was resolved by chromatography on DEAE-cellulose into two fractions characterized by the nature of the alkali light chains present. It was shown that even in an HMM-S1 preparation with an extensive fragmentation of the heavy chain a polyacrylamide gel electrophoresis analysis differentiates alkali light chains among the light fragmentation components. A non-fragmented HMM-S1 was obtained from a papain digest of myofibrils and the chromatographic analysis supplied further evidence of the separation of the two species of HMM-S1 present in rabbit white muscle myosin.