Biosynthesis of immunoglobulin G-binding factor in cattle lymphocytes

Synthesis of the IgG-binding factor was estimated by the amount of labeled [14C]hydrolysate of proteins in the total synthesized de novo protein. The obtained data showed that the IgG binding factor which was synthesized by blood lymphocytes of the normal cattle and that suffered from chronic leukemia had a molecular weight of 72 kDa and was revealed before and after restoration of S-S bonds as one peptide.     

Determination of quantitative parameters of Escherichia coli phagocytosis by mouse peritoneal macrophages

The fluorometric method was used to study guantitative parameters of phagocytosis of fluorescein-labeled Escherichia coli cells by mouse peritoneal macrophages. E. coli cells were conjugated with fluoresceinisothiocyanate (FITC) and then incubated with macrophages. At the end of the assay phagocytosis was arrested with a lysing solution (0.5% Triton X-100 in 0.01 M phosphate-buffered 0.15 M saline, pH 7.4). Trypan blue at a concentration of 0.04% was used as a quenching agent to differentiate between attachment and ingestion of E. coli cells. The time course analysis within this method showed that phagocytosis of E. coli cells was temperature and opsonin dependent. The number of E. coli cells ingested by macrophages increased rapidly during the initial 60 min of incubation at 37 degrees C. E. coli cells required opsonization with 5% native serum to achieve their optimal uptake. The uptake of nonopsonized bacteria by macrophages was significantly lower that that of opsonized ones (P < 0.05). It was demonstrated that sodium azide inhibited phagocytosis of E. coli cells by mouse peritoneal macrophages in a dose-dependent manner.     

Prediction of the three-dimensional structure of aflatoxin of Aspergillus flavus by homology modelling

Aflatoxins are polyketide-derived secondary metabolites produced by Aspergillus spp. The toxic effects of aflatoxins have adverse consequences for human health and agricultural economics. The aflR gene, a regulatory gene for aflatoxin biosynthesis, encodes a protein containing a zinc-finger DNA-binding motif. AFLR-Protein three-dimensional model was generated using Robetta server. The modeled AFLR-Protein was further optimization and validation using Rampage. In the simulations, we monitored the backbone atoms and the C-α-helix of the modeled protein. The low RMSD and the simulation time indicate that, as expected, the 3D structural model of AFLR-protein represents a stable folding conformation. This study paves the way for generating computer molecular models for proteins whose crystal structures are not available and which would aid in detailed molecular mechanism of inhibition of aflatoxin.     

Mapping the amino acid properties of constituent nucleoporins onto the yeast nuclear pore complex

Visualization of molecular structures aids in the understanding of structural and functional roles of biological macromolecules. Macromolecular transport between the cell nucleus and cytoplasm is facilitated by the nuclear pore complex (NPC). The ring structure of the NPC is large and contains several distinct proteins (nucleoporins) which function as a selective gate for the passage of certain molecules into and out of the nucleus. In this note we demonstrate the utility of a python code that allows direct mapping of the physiochemical properties of the constituent nucleoporins on the scaffold of the yeast NPC׳s cytoplasmic view. We expect this tool to be useful for researchers to visualize the NPC based on their physiochemical properties and how it alters when specific mutations are introduced in one or more of the nucleoporins. The code developed using Python is available freely from the authors.     

Interaction of blood lymphocyte Fc receptors with IgG during in vitro cultivation

Bovine blood lymphocytes taken from normal cows and those suffering from chronic lymphocytic leukemia were cultured in complete medium 199 with 10% of heat-inactivated fetal bovine serum. After a 48 hour culturing an enhanced quantity of the Fc-receptor bound fluoresceinated immunoglobulin G (IgG) was established. When lymphocyte fractions enriched with T- or B-cells were cultured, the binding capacity of Fc-receptors for IgG (48 hours after culture) increased in both the cell populations. A study of the kinetics of interactions of Fc-receptors with IgG showed that the increased number of Fc-receptors after culturing was followed by an enhanced affinity of Fc-receptors towards IgG. The affinity of Fc-receptors of blood lymphocytes of cows with chronic lymphocytic leukemia was lower than that of normal lymphocytes.     

The treatment of isolated genera

Problems presented by genera, or small groups of genera, which have been given family rank are reviewed, and the genera are divided into a number of categories according to the closeness of their affinity to other genera or families. Satellite genera that stand in close relation to families should be united with them. Binary families, that have been divided into two (or more) related families, should be re–united. Families connected by linking genera, should, logically, be united but practical considerations usually prevent this. Clusters of diverse but more or less distantly related genera present unusual problems, being treated either as several, often monogeneric families or as a loosely structured family. Truly isolated genera must be given family and often ordinal rank.     

Isolation of immunoglobulin G-binding factor from blood lymphocytes of cows with lymphocytic leukemia

Incubation of bovine blood lymphocytes in the medium without serum at 37 degrees C caused the spontaneous release of immunoglobulin G-binding factor (IBF-IgG), which was isolated from the medium by the affinity chromatography on IgG, immobilized on sepharose 4B. The electrophoretic analysis showed one polypeptide chain with a molecular weight of 72000 Dalton. The biological activity of IBF-IgG was tested using the EA-rosette inhibition technique. The antibodies, obtained against IBF-IgG, inhibited both the binding of fluoresceinizotiocianate-labeled IgG to lymphocytes and the EA-rosette formation.     

Effect of short-term culture of blood lymphocytes in vitro on the ability of Fcgamma-receptors to bind IgG1 and IgG2 and mediation of antibody-dependent cytotoxicity

The comparative study incubation influence at 37 degrees C on the lymphocyte Fc gamma-receptor (Fc gamma R) binding ability to IgG1 and IgG2 and on the antibody-dependent cell mediated cytotoxicity (ADCC) was performed. By means of the fluorometric binding assay it was determined that during 30 min of incubation the binding ability of Fc gamma R decreased while after 180 min of incubation it increased. Upon comparing both IgG1 and IgG2 binding abilities to lymphocytes no statistically important changes were noticed (p < 0.05). The changes in the binding ability of Fc gamma R for IgG1 and IgG2 had a similar pattern to the changes.