RESUMEN
Following up on a chapter on the Correlative Light and Electron Microscopy of Early Caenorhabditis elegans Embryos in Mitosis (MCB 79, 101-119), we present an adaptation of our established protocol for the ultrastructural analysis of either permeabilized or injected embryonic systems. We prepared both drug-treated early C. elegans embryos and fluorescently labeled sea urchin embryos of Lytechinus pictus for ultrastructural studies on animal cytokinesis. Here we focus on the initial preparation steps of postmitotic embryos for high-pressure freezing and subsequent electron microscopy with an emphasis on electron tomography. The advantages and limitations of our extended protocol will be discussed.
Asunto(s)
Citocinesis/genética , Tomografía con Microscopio Electrónico/métodos , Embrión no Mamífero/ultraestructura , Microscopía Electrónica/métodos , Animales , Caenorhabditis elegans/ultraestructura , Desarrollo Embrionario/genética , Mitosis/genética , Erizos de Mar/genética , Erizos de Mar/crecimiento & desarrollo , Erizos de Mar/ultraestructuraRESUMEN
Despite favorable thermodynamics, high-molecular weight and low-dispersity polyesters are difficult to synthesize biocatalytically in organic solvents. We have reported previously that the elimination of solvent can improve the kinetics and apparent equilibrium significantly (Chaudhary et al., 1997a). We now present the design and use of a batch-stirred enzyme reactor to control the biocatalytic polymerization. Using the reactor, polyester having a molecular weight of 23,400 Da and a polydispersity of 1.69 was synthesized in only 1 h at 60 degrees C. Additional factors like enzyme-deactivation kinetics, enzyme specificity, and initial exothermicity were investigated to develop a better understanding of this complex reaction system.
