Asunto(s)
Zinc/análisis , Animales , Enzimas/análisis , Humanos , Indicadores y Reactivos , Microquímica , Espectrofotometría Atómica/métodos , Zinc/sangre , Zinc/orinaRESUMEN
Iron-, manganese-, or magnesium-deficiency has been induced in Euglena gracilis. Each arrests cell proliferation, decreases the intracellular content of the deficient metal, and increases that of several other metals. Light and electron microscopy of stationary phase cells reveal that Fe-deficient (-Fe) cells are similar in size and shape to control organisms. Magnesium-deficient (-Mg) cells, however, are larger, and approximately 14% are multilobed, containing 2 to 12 lobes of equal size emanating from a central region. Individual (-Mg) cells and each lobe of multilobed cells contain a single nucleus. Manganese-deficient (-Mn) organisms are morphologically more heterogeneous than (-Fe) or (-Mg) cells. Most are spherical and larger than controls. Approximately 15% are multilobed but, unlike (-Mg) cells, contain lobes of unequal size with either zero, one, or several nuclei present in each. Nuclei of (-Mn) cells differ in size and shape from those of control, (-Fe), or (-Mg) cells. All three deficient cell types accumulate large quantities of paramylon. Other cytoplasmic structures, however, appear normal. Addition of Fe, Mn, or Mg to the respective deficient stationary phase cultures reverses growth arrest and restores normal morphology. The results suggest that Fe-, Mn-, and Mg-deficiencies affect different stages of the E. gracilis cell cycle.
Asunto(s)
Euglena gracilis/crecimiento & desarrollo , Hierro/metabolismo , Magnesio/metabolismo , Manganeso/metabolismo , Núcleo Celular/ultraestructura , Medios de Cultivo , Gránulos Citoplasmáticos/ultraestructura , Euglena gracilis/análisis , Euglena gracilis/citología , Euglena gracilis/ultraestructura , Hierro/análisis , Magnesio/análisis , Manganeso/análisis , Metales/análisis , Microscopía Electrónica , Organoides/ultraestructuraRESUMEN
The effects induced by Fe, Mn, or Mg deficiency or cold shock on the DNA content and histones of Euglena gracilis have been examined and compared to those produced by Zn deficiency. The DNA content of the stationary-phase organisms used as controls is 2.1 micrograms/10(6) cells. The DNA of stationary-phase iron-deficient (-Fe), magnesium-deficient (-Mg), manganese-deficient (-Mn), zinc-deficient (-Zn), and cold-shocked (CS) cells is increased to 3.0, 4.6, 6.2, 3.8, and 3.8 micrograms/10(6) cells, respectively. The electrophoretic mobilities of proteins solubilized with 0.4 N H2SO4 from CS, -Fe, -Mg, and -Mn cells are nearly identical and are characteristic of the five histone classes, H1, H2A, H2B, H3, and H4. In contrast, no histones are found in the equivalent acid extract from -Zn cells. The effect of micrococcal nuclease on chromatin from control, CS, and -Zn cells was examined. The chromatin of CS cells is 1.2-fold while that from -Zn cells is 10-30-fold more resistant to micrococcal nuclease digestion than is the chromatin of control cells. Thus, the chromatin of cells grown in Zn-deficient conditions differs markedly from that of organisms cultured in media deficient in Fe, Mn, or Mg or exposed to cold shock.