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1982 (1)
1979 (1)
1Author    Stefan AntohiRequires cookie*
 Title    Polycation-Bacterium Interactions and Wall Subunits as Endocytosis Factors. Topoisomeraselike Action of Basic Polypeptides Suggesting a 7th Class of Enzymes: The Stereases  
 Abstract    Lysine rich histone and polylysine are bacteriolytic for Bacillus subtilis and Escherichia coli cells, whereas histones H2A, H2B and H3, assayed separately are not. Polyarginine bacteriolysis of E. coli with polycation 10 ug/ml decreased with higher concentrations, the killed nonlysed cells exhibiting wall alterations. All bacteriolytic polycations were lytically effective under reciprocal shaking, but not under magnetic stirring conditions, demonstrating the requirement for cell lysis of mechanical fields developed in oscillatory movements. Scanning electron microscopy o f histone HI treated B. subtilis cells showed the formation of globular bodies (polionosomes) in the cell surface. The interference of Ca2+ and 0 °C exposure with the polycation action observed especially in E. coli, the polionosomes, and the dynamics in polycationic cell lysis, considered together, suggest the existence o f wall supramolecular subunits (murameres), defined by their ability to form polionosomes. The murameres undergoing reversible conformational transitions induced by ectobiological signals, e.g., Ca2+, would make up an uptake system. The involvement of this system in environmental interactions and D N A uptaking, as well as the general stereo-enzyme like nature o f the conformational changes caused by polycations are discussed. 
  Reference    Z. Naturforsch. 37c, 985—9 (1982); received December 10 1981/April 14 1982 
  Published    1982 
  Keywords    Polionosome, Muramere, Sterease, Ca2+, Uptaking System 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0985.pdf 
 Identifier    ZNC-1982-37c-0985 
 Volume    37 
2Author    Jürgen Van Der Bosch, Ilse Sommer, Heinz Maier, Willy RahmigRequires cookie*
 Title    Density-Dependent Growth Adaptation Kinetics in 3T 3 Cell Populations Following Sudden [Ca2+] and Temperature Changes. A Comparison with SV40-3T3 Cells  
 Abstract    Lowered extracellular [Ca2+ ] causes low growth rates and low stationary cell densities in 3T3 cell cultures as compared to physiological [Ca2+ ]. Under otherwise constant conditions the extra­ cellular [Ca2+ ] determines a stable stationary cell density, which can be readied by increase of net cell number or decrease of net cell number, depending on cell density at the time of [Ca2+ ] adjustment. SV40-3T3 cells do not show this [Ca2+] dependency. At 39 °C 3T3 and SV40-3T3 cell populations show an increased growth rate at low cell densities as compared to cell popula­ tions at 35 °C. Approaching the stationary density the growth rate of both cell sorts is reduced faster at 39 °C than at 35 °C, leading to lower stationary cell densities at 39 °C than at 35 °C. A temperature change from 39 °C to 35 °C or in the opposite direction can affect the stationary cell density of 3T3 cell populations only if applied before reduction of growth rate by density-dependent growth-inhibiting principles has taken place. 
  Reference    Z. Naturforsch. 34c, 279 (1979); received December 19 1978 
  Published    1979 
  Keywords    Ca2+, Temperature, Growth Control, 3T3 Cell, SV40-3T3 Cell 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0279.pdf 
 Identifier    ZNC-1979-34c-0279 
 Volume    34