Periodicity in the rise and fall of the numbers of the principal Staphylococcus aureus phage groups

The results of the phage typing of 5, 168 Staph. aureus strains isolated in a surgical hospital between 1959 and 1977 are analyzed for each year of this period. The wave of increase in the number of staphylococci belonging to phage group II which began, as discovered in this study, in 1965 and still showed no tendency towards decrease in 1977, as well as the periodicity of rises and falls in the number of staphylococci belonging to phage groups I and III are discussed and compared with the data contained in the literature. The authors come to the conclusion that Staph. aureus is subject to wave-like rises and falls in the number of strains belonging to the main phage groups of the species, and among them the strains belonging to phage groups I and III seem to be inversely related in respect of rises and falls in number, such changes occurring periodically at an interval of 10-12 years, while in the strains belonging to phage group II changes in number occur at a slower rate. The constant account of the percentage of phage groups I, II and III is recommended to ensure rational antibiotic therapy.     

Production of tetanolysin preparations and characteristics of their properties

As the result of the study of tetanolysin-producing Clostridium tetani strains, their populations have been found to be markedly heterogeneous with respect to the hemolytic activity of clone cultures. On the basis of normal and dialyzed cultures of selected variants with maximum activity the preparations of tetanolysin have been obtained, and their hemolytic activity and antigenic properties have been studied. Antihemolytic rabbit sera have also been obtained and characterized. Partially purified preparations of tetanolysin with high hemolytic activity have been obtained by the fractionation of C. tetani dialyzed cultures with ammonium sulfate.     

Purification of recombinant proteins with an example of tumor necrosis factor thymosin-α1

Hybrid protein, cancer necrosis factor thymosin-α1 (TNF-T), when synthesizing in strain-producer of Escherichia coli SG200-50 with plasmid pThy315, was a part of “inclusion bodies” mostly in the form of a high-molecular complex with other proteins due to the S-S bonds formation. An approach of purification of TNF-T has been proposed, which is based on the destruction of the complex in the presence of sodium dodecylsulfate (DDS-Na) and dithiotreitol (DDT) followed by gel-filtration on Sephadex G-100 and renaturation by ultrafiltration on hollow fibers. The method allows the isolation of electrophoretically homogeneous TNF-T containing no DDS-Na and having high cytotoxic activity against cancer cells of mouse adenocarcinome L-929. The yield of TNF-T achieved 80% relative its content in biomass and 30% relative the total protein.     

Preface

Molecular and Cellular Biochemistry -     

An efficient chemical approach to bispecific antibodies and antibodies of high valency

Irreversible chemical programming of monoclonal aldolase antibody (mAb) 38C2 has been accomplished with β-lactam equipped mono- and bifunctional targeting modules, including a cyclic-RGD peptide linked to either the peptide (d-Lys⁶)-LHRH or another cyclic RGD unit and a small-molecule integrin inhibitor SCS-873 conjugated to (d-Lys⁶)LHRH. We also prepared monofunctional targeting modules containing either cyclic RGD or (d-Lys⁶)-LHRH peptides. Binding of the chemically programmed antibodies to integrin receptors α(v)β(3) and α(v)β(5) and to the luteinizing hormone releasing hormone receptor were evaluated. The bifunctional and bivalent c-RGD/LHRH and SCS-783/LHRH, the monofunctional and tetravalent c-RGD/c-RGD, and the monofunctional bivalent c-RGD chemically programmed antibodies bound specifically to the isolated integrin receptor proteins as well as to integrins expressed on human melanoma M-21 cells. c-RGD/LHRH, SCS-783/LHRH, and LHRH chemically programmed antibodies bound specifically to the LHRH receptors expressed on human ovarian cancer cells. This approach provides an efficient, versatile, and economically viable route to high-valency therapeutic antibodies that target defined combinations of specific receptors. Additionally, this approach should be applicable to chemically programmed vaccines.     

The cost of mutualism in a fly-fungus interaction

The movement ability of individuals has become increasingly important to a variety of ecological questions. In this study, I investigate how plant structure and changes in body size through development affect the movement ability of a predaceous stinkbug, Podisus maculiventris, on three species of goldenrod (Solidago spp.) representing a wide range of surface complexities. I adapt existing techniques for quantifying movement in two dimensions to the study of movement on natural plant structures in three dimensions. These experiments indicate that plant structure and insect size are significant factors affecting the movement ability of P. maculiventris. Changes in movement ability due to factors of ontogeny and different habitat structures suggest that the scale of an individual’s ambit or ecological sphere of influence may vary within its lifespan. Considering the influence of ontogeny and habitat structure on movement ability may be useful to investigations of population dynamics, foraging behavior, and pest management. Received: 14 July 1999 / Accepted: 23 March 2000     

New Gene Crt(Curly Roots) Controlling Pea (Pisum sativum L.) Root Development

Using ethyl methane sulfonate (EMS) treatment of the seeds ofline SGE, a new mutant of pea (Pisum sativum L.) with alterationsin root development was obtained. The mutant phenotype dependson the density of the growth substrate: on sand (a high densitysubstrate) the mutant forms a small compact curly root systemwhereas on vermiculite (a low density substrate) differencesbetween the root systems of the mutant and wild type plantsare less pronounced. Genetic analysis revealed that the mutantcarries a mutation in a new pea gene designedcrt (curly roots).Gene crt has been localized in pea linkage group V. The mutantline named SGEcrt showed increased sensitivity to exogenousauxin and an increased concentration of endogenous indole-3-aceticacid (IAA) in comparison with the wild type line SGE. Copyright2000 Annals of Botany Company Pisum sativum L., root development, garden pea mutant, curly roots, auxin, environmental stimulus response     

Amphiphilic cationic peptides mediate cell adhesion to plastic surfaces

Four amphiphilic peptides, each with net charges of +2 or more at neutrality and molecular weights under 4 kilodaltons, were found to mediate the adhesion of normal rat kidney fibroblasts to polystyrene surfaces. Two of these peptides, a model for calcitonin (peptide 1, MCT) and melittin (peptide 2, MEL), form amphiphilic alpha-helical structures at aqueous/nonpolar interfaces. The other two, a luteinizing hormone-releasing hormone model (peptide 3, LHM) and a platelet factor model (peptide 4, MPF) form beta-strand structures in amphiphilic environments. Although it contains only 10 residues, LHM mediated adhesion to surfaces coated with solutions containing as little as 10 pmoles/ml of peptide. All four of these peptides were capable of forming monolayers at air-buffer interfaces with collapse pressures greater than 20 dynes/cm. None of these four peptides contains the tetrapeptide sequence Arg-Gly-Asp-Ser, which has been associated with fibronectin-mediated cell adhesion. Ten polypeptides that also lacked the sequence Arg-Gly-Asp-Ser but were nonamphiphilic and/or had net charges less than +2 at neutrality were all incapable of mediating cell adhesion (Pierschbacher and Ruoslahti, 1984). The morphologies of NRK cells spread on polystyrene coated with peptide LHM resemble the morphologies on fibronectin-coated surfaces, whereas cells spread on surfaces coated with MCT or MEL exhibit strikingly different morphologies. The adhesiveness of MCT, MEL, LHM, and MPF implies that many amphiphilic cationic peptides could prove useful as well defined adhesive substrata for cell culture and for studies of the mechanism of cell adhesion.