Obtaining monoclonal antibodies to Bordetella pertussis antigens

The immunization of mice with the protein fraction of B. pertussis strain 305 has made it possible to obtain hybridomas producing monoclonal antibodies to B. pertussis antigens. Ascitic fluids containing monoclonal antibodies react in the ELISA in high titers and actively agglutinate B. pertussis strains 305 and 475.     

Antigen-binding activity,structural characteristics and use of monoclonal antibodies to human alpha-1-microglobulin

Four monoclonal antibodies (mAbs), G6, F9, H8, and B2, against human alpha-1-microglobulin (A1M) have been produced and characterized. The parameters of affinity (K_p ～ 10⁹ M^?1), epitope specificity (the additively binding G6/F9, G6/H8, G6/B2, F9/H8, and F9/B2 pairs), and the observed effect of reversibility of structural changes induced by chemical agents allow use of these mAbs in biospecific methods of A1M purification and quantitative determination. The application of mAbs to an A1M enzyme immunoassay (analytical sensitivity—0.5 μg/l) and one step isolation of pure A1M by immunoaffinity chromatography was described.     

A case of experimental transmission of the causative agent of plague from Ornithodoros tartakovskyi ticks to fleas of the great gerbil

Biological interrelations between ectoparasites from the colonies of great gerbil were studied experimentally. Hungry fleas Coptopsylla lamellifer are able to feed on the ticks Ornithodoros tartakovskyi infected with plague and in so doing be infected with plague agent. Such feeding is identified as "heterovampirism".     

Synthetic studies in the series of polyene macrolide antibiotics. 5. Synthesis of methyl-2,4,6-trideoxy-2,4-di-C-methyl-alpha-L- gluco-hexopyranoside and methyl-2,4,6-trideoxy-2,4-di-C-methyl- alpha-L-manno-hexopyranoside, the stereoisomers of the C33-C38 fragment of amphotericin B

The synthesis of the gluco- and manno-stereoisomers of amphotericin B is described.     

Elemental distribution in striated muscle and the effects of hypertonicity: Electron probe analysis of cryo sections

A method of rapid freezing in supercooled Freon 22 (monochlorodifluoromethane) followed by cryoultramicrotomy is described and shown to yield ultrathin sections in which both the cellular ultrastructure and the distribution of diffusible ions across the cell membrane are preserved and intracellular compartmentalization of diffusabler ions can be quantitated. Quantitative electron probe analysis (Shuman, H., A.V. Somlyo, and A.P. Somlyo. 1976. Ultramicros. 1:317-339.) of freeze-dried ultrathin cryto sections was found to provide a valid measure of the composition of cells and cellular organelles and was used to determine the ionic composition of the in situ terminal cisternae of the sarcoplasmic reticulum (SR), the distribution of CI in skeletal muscle, and the effects of hypertonic solutions on the subcellular composition if striated muscle. There was no evidence of sequestered CI in the terminal cisternae of resting muscles, although calcium (66mmol/kg dry wt +/- 4.6 SE) was detected. The values of [C1](i) determined with small (50-100 nm) diameter probes over cytoplasm excluding organelles over nuclei or terminal cisternae were not significantly different. Mitochondria partially excluded C1, with a cytoplasmic/ mitochondrial Ci ratio of 2.4 +/- 0.88 SD. The elemental concentrations (mmol/kg dry wt +/- SD) of muscle fibers measured with 0.5-9-μm diameter electron probes in normal frog striated muscle were: P, 302 +/- 4.3; S, 189 +/- 2.9;C1, 24 +/- 1.1;K, 404 +/- 4.3, and Mg, 39 +/- 2.1. It is concluded that: (a) in normal muscle the "excess CI" measured with previous bulk chemical analyses and flux studies is not compartmentalized in the SR or in other cellular organelles, and (b) the cytoplasmic C1 in low [K](0) solutions exceeds that predicted by a passive electrochemical distribution. Hypertonic 2.2 X NaCl, 2.5 X sucrose, or 2.2 X Na isethionate produced: (a) swollen vacuoles, frequently paired, adjacent to the Z lines and containing significantly higher than cytoplasmic concentrations of Na and Cl or S (isethionate), but no detectable Ca, and (b) granules of Ca, Mg, and P = approximately (6 Ca + 1 Mg)/6P in the longitudinal SR. It is concluded that hypertonicity produces compartmentalized domains of extracellular solutes within the muscle fibers and translocates Ca into the longitudinal tubules.     

Studies on the Interaction of Ca2+ Ions with Some Fractions of the Neurospecific S-100 Protein

Abstract: Fractions of neurospecific S-100 protein were purified from bovine brain and their physicochemical properties were studied. Conformational changes caused by the binding of calcium to S-100 protein fractions were detected by means of differential and fluorescence spectroscopy. Fractions demonstrating opposite shifts of their spectra also differ in the distribution in double-phase system. The number of calcium-binding centers and their association constants were determined by means of equilibrium dialysis and gel filtration. The nature of the differences in the interaction of various S-100 protein fractions with calcium is discussed.     

A 13c-n.m.r. study of 1,6:2,3- and 1,6:3,4-dianhydro-β-D-hexo-pyranoses and their O-acetyl and deoxy derivatives

¹³C-N.m.r. spectra of all possible 1,6:2,3- and 1,6:3,4-dianhydro-β-D-hexo-pyranoses and their O-acetyl and deoxy derivatives are presented. Relations between chemical shifts of certain carbon atoms and the structure of the dianhydrides are outlined, and their application in structural analysis is discussed. Inversion of configuration of the oxirane ring from the endo to the exo position is associated with typical upfield-shifts for oxirane-ring carbon atoms C-2 or C-4, respectively. Possible inter-relationships between ¹³C-chemical shifts and steric and polar interactions in the dianhydro derivatives are discussed.     

Cholesterol transport between red blood cells and lipoproteins contributes to cholesterol metabolism in blood

Lipoproteins play a key role in transport of cholesterol to and from tissues. Recent studies have also demonstrated that red blood cells (RBCs), which carry large quantities of free cholesterol in their membrane, play an important role in reverse cholesterol transport. However, the exact role of RBCs in systemic cholesterol metabolism is poorly understood. RBCs were incubated with autologous plasma or isolated lipoproteins resulting in a significant net amount of cholesterol moved from RBCs to HDL, while cholesterol from LDL moved in the opposite direction. Furthermore, the bi-directional cholesterol transport between RBCs and plasma lipoproteins was saturable and temperature-, energy-, and time-dependent, consistent with an active process. We did not find LDLR, ABCG1, or scavenger receptor class B type 1 in RBCs but found a substantial amount of ABCA1 mRNA and protein. However, specific cholesterol efflux from RBCs to isolated apoA-I was negligible, and ABCA1 silencing with siRNA or inhibition with vanadate and Probucol did not inhibit the efflux to apoA-I, HDL, or plasma. Cholesterol efflux from and cholesterol uptake by RBCs from Abca1^+/+ and Abca1^−/− mice were similar, arguing against the role of ABCA1 in cholesterol flux between RBCs and lipoproteins. Bioinformatics analysis identified ABCA7, ABCG5, lipoprotein lipase, and mitochondrial translocator protein as possible candidates that may mediate the cholesterol flux. Together, these results suggest that RBCs actively participate in cholesterol transport in the blood, but the role of cholesterol transporters in RBCs remains uncertain.