Pseudomonas lectin PA-I detects hybrid product of blood group AB genes in saliva

Summary Pseudomonas aeruginosa galactophilic lectin PA-I exhibits an outstanding affinity for soluble hybrid oligosaccharide products of human A and B genes in saliva of heterozygous AB individuals. Neither A nor B salivas, nor an artificial mixture of them, inhibit PA-I hemagglutinating activity to the same extent as saliva from heterozygotes. Other lectins examined do not exhibit this property.     

Differential molecular regulation of processing and membrane expression of Type-I BMP receptors: implications for signaling

The Type-I bone morphogenetic protein receptors (BMPRs), BMPR1A and BMPR1B, present the highest sequence homology among BMPRs, suggestive of functional similitude. However, sequence elements within their extracellular domain, such as signal sequence or N-glycosylation motifs, may result in differential regulation of biosynthetic processing and trafficking and in alterations to receptor function. We show that (i) BMPR1A and the ubiquitous isoform of BMPR1B differed in mode of translocation into the endoplasmic reticulum; and (ii) BMPR1A was N-glycosylated while BMPR1B was not, resulting in greater efficiency of processing and plasma membrane expression of BMPR1A. We further demonstrated the importance of BMPR1A expression and glycosylation in ES-2 ovarian cancer cells, where (i) CRISPR/Cas9-mediated knockout of BMPR1A abrogated BMP2-induced Smad1/5/8 phosphorylation and reduced proliferation of ES-2 cells and (ii) inhibition of N-glycosylation by site-directed mutagenesis, or by tunicamycin or 2-deoxy-d-glucose treatments, reduced biosynthetic processing and plasma membrane expression of BMPR1A and BMP2-induced Smad1/5/8 phosphorylation.     

Effect of acetylcholine on the osmotic fragility of papain-treated and untreated human red blood cells

Résumé L'hémolyse des globules rouges, incubés avec de fortes concentrations d'acétylcholine en conditions isotoniques est due à l'acide acétique libéré dans le milieu. Cette hémolyse est complètement inhibée par l'inactivation de l'acétylcholinestérase érythrocytaire avec la papaïne.

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This work was supported by research grant No. 151-1-31 of the Research Committee of Bar-Ilan University.     

Comparative study of the sensitivity of acetylcholinesterases and cholinesterases from animal and bacterial sources to inhibition by serotonin and its derivatives

Summary Serotonin was found to inhibit human erythrocyte and electric-eel acetylcholinesterase activities. The serotonin amino group, free of negative charges in its vicinity and its hydroxyl group, were important for the inhibition. Serotonin precursors and several related compounds had little or no effect. Human plasma cholinesterase was also inhibited by serotonin and tryptamine. In contrast to these animal enzymes, the cholinesterase ofPseudomonas aeruginosa was refractory to serotonin and its derivatives under the same experimental conditions.     

Comparative study of the sensitivity of acetylcholinesterases and cholinesterases from animal and bacterial sources to inhibition by serotonin and its derivatives.

Serotonin was found to inhibit human erythrocyte and electric-eel acetylcholinesterase activities. The serotonin amino group, free of negative charges in its vicinity and its hydroxyl group, were important for the inhibition. Serotonin precursors and several related compounds had little or no effect. Human plasma cholinesterase was also inhibited by serotonin and tryptamine. In contrast to these animal enzymes, the cholinesterase of Pseudomonas aeruginosa was refractory to serotonin and its derivatives under the same experimental conditions.     

Pseudomonas lectin PA-I detects hybrid product of blood group AB genes in saliva

Pseudomonas aeruginosa galactophilic lectin PA-I exhibits an outstanding affinity for soluble hybrid oligosaccharide products of human A and B genes in saliva of heterozygous AB individuals. Neither A nor B salivas, nor an artificial mixture of them, inhibit PA-I hemagglutinating activity to the same extent as saliva from heterozygotes. Other lectins examined do not exhibit this property.     

Estimation of nonspecific lectin-mediated staining of glutaraldehyde-fixed cells

Summary Lectin-mediated stainings are widely used for the visualization of carbohydrate-carrying cellular components using the electron microscope. The use of glutarladehyde-fixed cells for these stainings introduces the possibility of low nonspecific lectin-trapping by the glutaraldehyde which coats the cells. This trapping was estimated by means of peroxidase-binding to human leukocytes,Tetrahymena pyriformis andEscherichia coli cells and was shown to be prevented by rinsing the glutaraldehyde-fixed cells in an amino acid solution before exposure to the lectin.     

The osmotic fragility of thrombocytes of laboratory animals

Zusammenfassung Die osmotische Resistenz von Thrombozyten fünf verschiedener Tierarten wurde untersucht und mit der osmotischen Resistenz menschlicher Thrombozyten verglichen. Ein Zusammenhang zwischen der osmotischen Resistenz der Thrombozyten und Erythrozyten der gleichen Tierart konnte gezeigt werden.