Effect of hydromechanical forces on the production of filamentous haemagglutinin and pertussis toxin ofBordetella pertussis

Summary The production ofBordetella pertussis extracytoplasmic filamentous haemagglutinin (FHA) and pertussis toxin (PT) in a bioreactor under stirring conditions was studied in order to investigate the effect of hydromechanical forces on yields of both antigens. It was shown that FHA loses its haemagglutinin activity when the power transmitted by the agitator and the aerator per unit volume increases, whereas PT production is not affected. The loss of FHA activity can be explained by the action of shear forces on the filamentous structure of this antigen.Nomenclature C^* dissolved oxygen saturation concentration - C₁ dissolved oxygen concentration - D impeller diameter - power transmitted by the agitator and the aerator per unit of liquid volume - E_m maximum local energy dissipation rate per unit of liquid volume - K_La volumetric oxygen transfer coefficient - N impeller speed - Pg power input in aerated system - qO₂m maximum specific oxygen consumption rate - R_e Reynold number (D²N /) - VVM volume of air per volume of fermentation broth per minute - Xm maximum of biomass concentration - o Kolmogorov-microscale - fermentation broth viscosity - fermentation broth kinematic viscosity - fermentation broth density - expt experiment     

Plasmid pKM101 sensitization of Escherichia coli strains to the action of ionizing radiation: the effect of the plasmid on survivability and induced mutagenesis

The wild type Escherichia coli K-12 has been shown to be sensitized to inactivation by gamma-irradiation by the plasmid pKM101. The dnaA strains of E. coli are more sensitive to gamma-rays killing effect, as compared with the wild type E. coli, pKM101 plasmid showing only slight sensitizing effect. "Cis" or "trans" position of the plasmid in relation to the chromosome plays no role in sensitization, while the plasmid effect on UV-induced killing and mutability depends on "trans" position of the plasmid before irradiation. gamma-Rays induced mutability to prototrophy is completely dependent on the presence of pKM101 in "trans" in wild type and dnaA strains before irradiation.     

Effect of methyl-cyclodextrin on adenylate cyclase activity of Bordetella pertussis

The activity of Bordetella pertussis extracytoplasmic adenylate cyclase (AC) decreased during decelerating growth phase in a Stainer-Scholte medium. Neither proteolytic activity nor virulence variation (phase variation; antigenic modulation) appears to be responsible for the observed activity fall. The addition of methyl--cyclo-dextrin enhances AC activity and prevents the inhibition of AC activity by fatty acids. Cyclodextrin could entrap inhibitors increasing in this way the AC activity. These results show that the inclusion of cyclodextrin in the culture medium increases the AC activity.D.F. Hozbor and O.M. Yantorno are with the Centro de Investigación y Desarrollo en Fermentaciones Industriales (CINDEFI), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, (1900) La Plata, Argentina. A. Samo is with the Comisión de Investigaciones Cientificas de la Provincia de Buenos Aires.     

Glycoprotein desorption from the surface of human peripheral blood lymphocytes after irradiation with short-wave UV rays

The vital quantitative method of the cell coat (outer perimembraneous layer-OPML) identification with alcian blue (AB), which was earlier developed for the rat hepatoma cells and human erythrocytes, has been adopted for human blood lymphocytes. AB is bind by glycoproteins, glycolipids and acid mucopolysaccharides of the cell surface. Under experimental condition to be used each lymphocyte adsorbed 1.1 X 10(-10) g of AB. Irradiation with non-lethal doses of UV light induced a decrease in AB sorption by 8-13%. At the same time, the release of substances took place, some properties of which are similar to those of glycoproteins. A conclusion is made that the lymphocyte OPML was destroyed by UV rays and its components released into the extracellular space. The role of this phenomenon is discussed in terms of the therapeutic effect of UV light.     

Characteristics of the composition of higher fatty acids in methicillin-resistant and methicillin-sensitive Staphylococci

The composition of fatty acids of methicillin-resistant (MR) and methicillin-sensitive (MS) strains of Staph. aureus and Staph. epidermidis was determined with the method of reactive gas liquid chromatography. The MS staphylococci of the above species differed by the content of acids with branched chains of iso- and anteisostructures and straight chains. Anteisoacids in the cells of Staph. epidermidis amounted almost to 80 per cent of the total number of the acids, while in the cells of Staph. aureus, their total number amounted only to a half of the fatty acid pool. Comparison of the composition of the fatty acids of the MS and MR strains of Staph. aureus revealed differences in the proportions of the anteiso- and isoacids. The total number of the long-chain C20.0 acid in the cells of Staph. epidermidis resistant to methicillin was lower as compared to that in the sensitive cells.     

Role of the product of recB-gene in the thymine-less death and characteristics of this phenomenon in a thy-recB--mutant of Escherichia coli K-12]

Thymine requiring mutants of rec+ and recB- Escherichia coli strains have been tested for their response to thymine deprivation. Exonuclease V-deficient mutant is less sensitive to thymine deprivation than the wild type strain, because there is no lag period at thymineless death of recB- thy- cells. However, the mechanism of thymineless death of thy- rec+ and thy- recB- cells may be different. Two types of thymineless death are proposed to exist. The first type is due to DNA primary structure damages (single-strand breaks or gaps), accompanied by DNA degradation. The restoration of the balance disturbed by the thymine deprivation between DNA and protein synthesis rates by their balanced inhibition promotes a complete repair of structural damages in DNA and prevents the death of rec+ cells. The second type of thymineless death is not linked with the formation of DNA damages, and this is observed in recB- thy- mutant, defective in exonuclease V.     

Functional and structural changes in the surface of human erythrocytes after irradiation by different wave lengths of UV rays. III. The immediate effect of the autotransfusion of UV-irradiated blood

The autotransfusion of UV-irradiated blood (70-200 ml) results in the structural modification of cell surface in all the circulating erythrocytes of cardiological patients. The effect is registered within 1 hour after transfusion and involves some decrease in the distribution coefficient of erythrocytes registered in two-phase polymer system dextran-poly(ethylene glycol), which depends on membrane surface properties other than charge. This effect is suggested to be responsible for the main peculiarities of the therapeutic effect of UV-irradiated blood autotransfusion--high rate of appearance, prolongation and wide spectrum of the therapeutic action.     

Effects of experimental factors on the tinctorial properties of structural elements of the mammalian cerebral cortex (intravital microscopic study)]

Effects of a vital dye--methylene blue--on brain neuronal structures were investigated in the alive preparations of mammal brains by means of contact optical microscope in falling polarization light. Tinctorial properties of neuronal cortical structures were studied under the influence of a number of experimental factors (illumination conditions, dye concentration, temperature regime and oxygen supply to the preparation). A certain dependence in the character of dyeing and bleaching neuronal cells on the factors mentioned above was stated. Conditions for appearance of the alternating photodynamical effect and measures to prevent it were clarified. Practical recommendations were given for application methylene blue in prevital morphological investigations of mammal central nervous system.     

Cultivation of human plasmacytoma cells

Current knowledge of primary culturing and establishment of continuous cell lines from human plasmacytomas are reviewed. The cells derived from chronic monoclonal tumors are capable of proliferating in culture no more than for 3 weeks. The enrichment of the media with nutrient supplements and growth factors does not improve the cell survival. Most of the described stable cell lines were derived from malignancies of the late stages of tumor progression. Cell lines producing complete molecules of immunoglobulins were established with the aid of sophisticated culturing methods. The microenvironment and growth factors in culture system favoured the survival of transformed plasma cells which retained a high level of differentiation.     

Effect of UV-irradiated donor blood on the colony-forming ability of human bone marrow cells in culture

A possible mechanism of the hemopoiesis stimulation by UV and solar radiation was studied. The UV irradiation of leucocyte-enriched donor serum results in increasing the colony formation activity of the serum. The addition of such a serum but depleted of leucocytes to human bone marrow cells in semisolid agar culture stimulates its colony formation by 1.5-3 times. A serum depleted of leucocytes before the irradiation has not this property. It is supposed that cell surface glycoproteins, desorbing into the serum under UV irradiation, induce the colony formation activity of UV-irradiated blood.