Film Reviews

Vision of Juazeiro . 1970. Directed by Eduardo Escorel
Chichicastenango . 1987. A video by Claudia Feldmar
Comalapa: Traditions and Textures . 1987. A video by Claudia Feldmar
Holy Week in Antigua, Guatemala . 1987. A video by Claudia Feldmar
Sacred Games: Ritual Warfare in a Maya Village . 1988. A film by Thor Anderson
Peru—When the World Turned Dark . 1988. Produced by Maria Luisa Lobo and directed by Gianfranco Annichini     

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.     

Purification and characterization of a protein inhibitor of calcium-dependent proteases from rat liver

Soluble extracts of rat liver contain a protein inhibitor of calcium-dependent proteases. The inhibitor has an apparent M_r = 250,000 and is separated from the calcium-dependent proteases by gel-filtration chromatography in the presence of EGTA. The inhibitor has been purified by affinity chromatography using a calcium-dependent protease covalently linked to Affi-Gel 15. The inhibitor specifically binds to this affinity resin in a calcium-dependent manner and elutes in the presence of EDTA or EGTA. The purified inhibitor appears as a single protein with M_r = 125,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Presumably it is a dimer under nondenaturing conditions. The inhibitor inhibits each of two calcium-dependent proteases from rat liver and from other tissues and species. However, it has no effect on any other protease tested.     

Immunoglobulin classes of human serum antibodies in vaginal candidiasis

The titre and immunoglobulin class of antibodies against Candida albicans in serum from 60 non-pregnant women was determined. IgG titres up to 132, IgA titres up to 18, and IgM titres up to 14 were detected in 30 women with vaginal candidiasis. Similar titres were found in 20 women harbouring yeasts in the mouth or rectum, and in 10 women who were not harbouring yeasts in the vagina, mouth or rectum. Serum fractionation confirmed that antibodies to C. albicans are found in the three immunoglobulin classes and that these antibodies reside in highest titre in the IgG class. No secretory IgA antibodies against C. albicans were detected in the serum of these women.     

Immunospecificity of nuclear antigens in chicken erythroid cells

Summary Specific antisera were produced against chicken reticulocyte dehistonized chromatin. The antisera reacts strongly with chicken reticulocyte chromatin, but only marginally with chicken erythrocyte chromatin. There is no reticulocyte antigen detected in chicken liver. Reticulocyte maturation is accompanied by a gradual decrease in the chromatin immunological activity and template capacity. The reduction of immunological activity is due to the change of chromatin conformation during erythrocyte maturation. Dehistonization and sonication of erythrocyte chromatin raises the erythrocyte chromatin immunological activity to levels similar to those of reticulocyte chromatin. The erythrocyte nuclear antigens are class specific, not being found in frog erythroid cell or murine Friend leukemia cell chromatins.     

Cyanine dye structural and voltage-induced variations in photo-voltages of bilayer membranes

Summary Flash illumination alters the voltage across bilayer lipid membranes in the presence of certain cyanine dyes. The waveforms of the photo-voltage vary systematically with dye structure and imposed transmembrane voltage. Experimental results are reported for 27 positively charged cyanine dyes, primarily oxazole derivatives, using lecithin/oxidized cholesterol bilayer membranes and 10-mm sodium chloride solutions. Several dyes do not induce any photo-voltages. Examples are 3,3 diethyl 9 ethyl 2,2 oxacarbocyanine iodide, 3,3 diethyl 2 oxa 2 thiacyanine iodide, and 3,3 dimethyl 2,2 indocarbocyanine iodide. Several dyes, when added to one side of the membranes, induce monophasic waveforms. Examples are 3,3 dimethyl 2,2 oxacarbocyanine chloride, and 3,4,3,4 tetramethyl 2,2 oxazalinocarbocyanine iodide. Other dyes induce a photo-voltage only if transmembrane voltages are imposed. These waveforms are biphasic with some dyes (3,3 diethyl 2,2 oxacarbocyanine iodide, for example) and monophasic with other dyes (3,3 dibutyl 2,2 oxacarbocyanine iodide, for example).The photo-voltage waveforms are explained by models that consider the movement of charged dye molecules within the membrane, following optical excitation. The dye movements are probably induced through charge rearrangements in the dye associated with long-lived triplet states, isomerization, or through excimer formation. These results provide information on the location and orientation of the dye molecules within bilayer membranes. The variations which occur in the waveforms with applied voltage indicate that these membranes are fluid in the direction perpendicular to the membrane plane.