Biosynthesis of intestinal microvillar proteins Rapid expression of cytoskeletal components in microvilli of pig small intestinal mucosal explants

AbstractUsing alkaline extraction to separate cytoskeletal and membrane proteins of intestinal microvilli, the kinetics of assembly of these two microvillar protein compartments was studied by pulse-chase labelling of pig small intestinal mucosal explants, kept in organ culture. Following a 10 min pulse of [35S]methionine, the membrane proteins did not appear in the microvillar fraction until after 40–60 min of chase. In contrast, the cytoskeletal components, of which the 110-kDa protein and villin were immunologically identified, were expressed in the microvillar fraction immediately after the 10 min pulse. These different kinetics of appearance indicate that the two microvillar protein compartments have separate mechanisms of biosynthesis and microvillar expression

Gaining insight into the role of serine 282 in B. napus FAE1 condensing enzyme

AbstractTo gain some insight whether there is an absolute requirement for the serine 282 to yield a functional fatty acid elongase 1 condensing enzyme we have introduced point mutations in the FAE1 coding sequence which led to the substitution of serine 282 with several aliphatic or aromatic amino acids. The mutated FAE1 polypeptides were expressed in yeast. Gas chromatography analyses of the fatty acid methyl esters from yeast lysates and fatty acid elongase activity assays demonstrated that there is not an absolute requirement for serine at position 282 to yield a functional FAE1 condensing enzyme

The Dardanelles Campaign

Effectiveness in five warfare elements is necessary for the United States Navy to achieve the maritime dominance discussed in the strategic vision of littopral warfare, Forward…from the Sea : surface warfare, undersea warfare, amphibious warfare, combat logistics, and mine warfare. The fifth element , mine warfare, has been elevated from its traditional, often neglected, supporting role

Magnetic Characterization of Rare-Earth Barium Cuprate Superconductors

We report magnetic characterization of barium rare-earth cuprate superconductors to determine critical current densities as a function of rare-earth constituent. A vibrating sample magnetometer was used to measure M-H loops for fields to 15 kOe of oriented single crystals. Critical current densities are insensitive to rare-earth constituent despite the magnetic moment on the rare-earth ion. Values of critical current densities in the a-b plane vary from 3×105 A/cm2 at 10 K to 2×104 A/cm2 at 77 K. Anisotropy in the critical current density in the a-b plane and perpendicular to this plane was a factor of 2 in a Ba2YbCu3O7 crystal at T=38 K. Aluminum impurities lower critical currents but also reduce the superconducting transition temperature

Low-Field Flux-Flow Resistivity in Bi2.2Sr2Ca0.8Cu2BO8+

Current-voltage characteristics of single crystals of the 84-K superconducting phase Bi2.2Sr2Ca0.8Cu2BO8+ show no threshold behavior in small magnetic fields at 5080 K, despite large zero-field critical currents which are only weakly field-dependent at low temperatures (\u3c20 K). We attribute this to a low-field flux-flow resistivity which shows an empirical scaling behavior near Tc and which we can use to infer some basic properties of the superconductor. This behavior is intrinsic to Bi2.2Sr2Ca0.8Cu2BO8+ and has crucial implications for its technological potential of the compound

Magnetic Behavior of Diluted Lanthanoid-Pnictide Systems

We describe a new class of low-carrier-density magnetic materials based on lanthanide-substituted scandium and yttrium pnictides. In general, these III-V compounds have energy gaps in the vicinty of 1 eV, and like most of the lanthanide pnictides, form in the B1 (rocksalt) structure. Substitution of rare earths for Y or Sc to form solid solutions is readily achieved. For example, we have produced GdxY1-xN by reactive magnetron cosputtering, and obtained epitaxial growth on sapphire substrates resulting in high-quality single-crystal thin films. These films exhibit moderately low carrier densities and high mobilities, and have interesting magnetic properties at low temperatures. In this paper we present a preliminary look at some of the properties of these materials

Critical Current Densities in Single-Crystal Bi2.2Sr 2Ca0.8Cu2O8+Δ

We report transport and magnetic measurements of critical current densities in single crystals of high Tc superconductors in the Bi-Sr-Ca-Cu-O system. Transport measurements of Jc were made using a pulse method, while a vibrating sample magnetometer was used to measure M-H loops of oriented crystals in fields up to 15 kOe. Values for transport Jc in zero applied field are higher than those of Ba2YCu3O 7 single crystals at comparable temperatures. Also we observe a strong magnetic field dependence for Jc at temperatures above ∼20 K