Bf polymorphism. A very fast variant from Nigeria

Summary In a collection of Nigerian serum samples typed for alleles of factor B of the alternative complement pathway, a very high frequency of Bf^F was found (0.69). In addition, a new variant was found in two samples. This variant (F^1.29) moved faster than BfF₁. It was hemolytically active.Supported in part by The Medical Research Council of Canada     

Fucose-containing polysaccharides in the brown algae Ascophyllum nodosum and Fucus vesiculosus

The fucose-containing, sulfated polysaccharides from Ascophyllum nodosum and Fucus vesiculosus were isolated by extraction with water adjusted to pH 2. Pure fractions were carefully separated by fractional precipitation with ethanol from aqueous solutions containing magnesium or calcium chloride. Progress in the fractionation efforts and purity of the fractions isolated were established by free-boundary and cellulose acetate clectrophoresis. Ascophyllan, two “complexes”, and a galactofucan were isolated from A. nodosum. An ascophyllan-like fraction, and a “complex” were isolated from F. vesiculosus. Mild, acid hydrolysis (0.02m hydrochloric acid, 1 h, 80°) converted each of the “complexes” into an electrophoretically faster-moving and a slower-moving component. The “complex” from F. vesiculosus comprised a greater proportion of the extract than did the two “complexes” from A. nodosum. In addition, the Fucus “complex” was richer in fucose*. However, the data suggest that neither species contains a pure fucan sulfate in the native state.     

Production and partial characterization of monoclonal antibodies specific for the gamonts of Eimeria tenella.

Thirteen hybridomas secreting monoclonal antibodies (Mabs) specific for the sexual stages (gamonts) of Eimeria tenella were produced by fusing spleen cells of gamont-immunized RBF/Dn mice with FOX-NY myeloma cells. A Mab subisotype profile revealed 1 IgG2a and 12 IgG1. All Mabs demonstrated a similar binding pattern when incubated with parasitic gamonts as determined by the indirect fluorescent antibody test. Ascitic fluid containing Mab (GD9 (IgG1) was produced and used to immunize chicks passively per os. There was a 34% decrease (P less than 0.05) in oocyst output from immunized chicks when compared to control chicks. Passively immunized chicks also had reduced cecal lesion scores when compared to control chicks. These results suggest that Mab GD9 partially inhibited the fertilization process of E. tenella.     

Modifiers of bx1 alter the distribution of Ubx proteins in haltere imaginal discs of Drosophila.

The bithorax (bx) mutations in the Ultrabithorax (Ubx) gene of Drosophila melanogaster cause homeotic transformations of anterior third thoracic structures (T3a) toward anterior second thoracic structures (T2a) in the adult fly. A corresponding loss of Ubx protein expression in T3a of bx imaginal discs has been observed (White and Wilcox, 1985). We describe two genetic loci which modify the bx-induced transformation. A locus which we map very close to the pink peach (pp) gene suppresses the bx1 phenotype. In contrast, mutations in the suppressor of sable (su(s)) gene enhance the bx1 phenotype. A correlation was observed between patterns of Ubx protein expression and the phenotypic transformations observed.     

Quantitative immunoassay of total cellular GAP junction protein connexin32 during liver regeneration using antibodies specific to the COOH-terminus.

A radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) were used to determine relative concentrations of liver connexin32 (CX32) in rats. The RIA and ELISA utilize synthetic peptides corresponding to regions of the carboxyl-terminus and antibodies raised in rabbits against these peptides. Assuming that affinities of antisera are similar for peptide and native CX32, total cellular CX32 was found to exceed the amount of gap junction protein at the cell surface calculated from morphometric analyses by 1.5-2.0 fold. This finding raises the possibility that some of the protein is present in cytoplasmic compartments or as occult precursors in the plasma membrane. Studies of CX32 content in regenerating rat liver support this conclusion and show a time course of loss and recovery of CX32 that agrees with those reported in studies using other techniques.     

Use of dual wavelength spectrophotometry and continuous enzymatic depletion of oxygen for determination of the oxygen binding constants of hemoglobin

A small stopped-flow cuvette was built into a computer-controlled Cary 210 spectrophotometer. The enzymatic depletion of oxygen in solutions of hemoglobin and myoglobin was initiated by flowing the hemeproteins with the enzyme against a solution of the hemeproteins containing the appropriate substrate. The deoxygenation was homogeneous throughout the solution. Oxygen activity was calculated at each instant of time from the fractional saturation of Mb, determined from observations at the Hb/HbO2 isosbestic wavelength. Fractional saturation of Hb was determined from absorbances at the Mb/MbO2 isosbestic wavelength. The spectrophotometer cycled between these two wavelengths during the deoxygenation. The deoxygenation of HbO2 was largely complete in 20-25 min, whereas the deoxygenation of MbO2 was allowed to proceed for about 1 h. This procedure eliminates equilibration of Hb solutions with a gas phase and replaces oxygen electrode readings with spectrophotometric sensing by Mb, providing essentially instantaneous determinations of oxygen activity and hence 250-500 or more independent data points per run. The Mb and Hb data vectors require several manipulations to correct for small relative displacements in time and for small non-isosbestic effects. Detailed consideration of the enzyme kinetics allowed oxygen activities to be determined in regions where Mb is a poor sensor. Studies of HbO2 deoxygenation as a function of wavelength show that the determination of the four Adair constants requires in addition the determination of three spectroscopic parameters. Values of the apparent Adair constants, determined without these spectroscopic parameters, depend strongly on the monitoring wavelength.     

Chlamydia trachomatis contains a protein similar to the Legionella pneumophila mip gene product

A 27kDa Chlamydia trachomatis L2 protein was characterized by the use of monoclonal antibodies and by two-dimensional gel electrophoresis. The protein was shown to be located in the membrane of reticulate bodies as well as elementary bodies. Its synthesis could be detected from 10 hours post-infection. Cloning and sequence analysis of the distal part of the gene revealed an open reading frame of 175 amino acids. Comparison of the deduced amino acid sequence with the NBRF data base revealed significant homology between the 27 kDa chlamydial membrane protein and the product of the macrophage infectivity potentiator (mip) gene of Legionella pneumophila.