Salt-soluble lectins of corn grain

Lectins extracted from corn (Zea mays L.) kernel with Tris-HCl buffer pH 7.5 were isolated from the crude extract by affinity chromatography on Sepharose 6B-N-acetyl-d-galactosamine and Sepharose 6B-methylα-d-mannoside, and also by lectin affinity chromatography using concanavalin A and Lens culinaris lectin as ligands. According to preferential monosaccharide specificity, salt-soluble lectins of corn seed comprise at least two distinct types: N-acetyl-d-galactosamine-interactive and mannose-interactive lectins. The extracted lectins are unstable, with a tendency to form aggregates during storage.     

Different temperature profiles of enzyme secretion by two common strains ofTrichoderma reesei

Summary We have investigated the effects of high and low temperature on the synthesis and secretion of cellulases and other enzymes by two common and readily available strains ofTrichoderma reesei. While some effects were similar in both strains QM9414 and RUT-C30 (a reduction in cellulase production but stimulation of xylanase production at high temperature, and alterations in expression of the cellulase complex at low temperature), some specific differences between the strains were determined, most significantly an enhanced specific secretion rate (secretion/growth) at low growth temperature for QM9414.     

Determination of trace elements in standard reference materials by the ko-standardization method

Biological Trace Element Research - The ko-standardization method is suitable for routine multielement determinations by reactor neutron activation analysis (NAA). Investigation of NIST standard...     

Typing of Verotoxins by DNA Colony Hybridization with Poly- and Oligonucleotide Probes,a Bead-Enzyme-Linked Immunosorbent Assay,and Polymerase Chain Reaction

To identify the type of Verotoxins (VT) produced by Verocytotoxin-producing Escherichia coli (VTEC), a sensitive bead-enzyme-linked immunosorbent assay and polymerase chain reaction with common and specific primers to various VTs (VT1, VT2, VT2vha, VT2vhb, and VT2vp1) were developed. Together with colony hybridization tests with oligo- and polynucleotide probes, these methods were applied to VTEC isolates to type the VT produced. The toxin types of 26 of 37 strains were identified, but the reaction profiles in assays of the remaining 11 strains suggested the existence of new VT2 variants. The application of these identification procedures may be useful as a tool for clinical and epidemiological studies of VTEC infection.     

Structural and functional homology between the 29 kD rat liver nucleoprotein and the high mobility group 1 protein

A 29 kD soluble rat liver nucleoprotein (p29) has increased binding affinity for the hormone responsive element (RE) of the rat haptoglobin (Hp) gene during the acute-phase reaction. In this work the possibility of its structural and functional homology to the high mobility group 1 (HMG1) nonhistone protein constituent of chromatin was examined. The results of two-dimensional gel electrophoresis, Southwestern and Western immunoblot analyses, showed that p29 and HMG1 are homologous protein species. On the basis of in vitro and in vivo phosphorylation/dephosphorylation experiments, we discuss the modulatory role of phosphate groups in view of the structure and function of p29.     

Sialosylcholesterol Effects on Reconstitution of Microfilament and Glia Filament

Abstract: The effects of α-sialosylcholesterol (α-SC) on formation of either microfilament or glia filament of rat astrocytes were investigated using a reconstitution system. Polymerization of the depolymerized microfilament preparation that had been extracted from a crude cytoskeletal fraction of rat astrocytes, in the presence of 100 m M KCI and 10 m M MgCI₂, was suppressed in a dose-dependent manner by α-SC. α-SC inhibited polymerization of G-actin in a similar manner. The intensity of a-SC inhibition of G- actin polymerization was as great as that of microfilament polymerization, suggesting that the inhibition of microfilament polymerization by α-SC was due to the direct action of α-SC on actin, the main component of microfilament. α-SC depolymerized partly the polymerized microfilament preparation, which resembled F-actin (microfilament-like filaments). α-SC suppressed, in a dose-dependent manner, polymerization of a glia filament preparation that had been extracted from astrocyte cytoskeletons in the presence of phalloidin. An increase in the amount of added α-SC (up to 15 n M ) decreased the amount of the larger glia filament-like filaments, which were 10 nm thick and centrifuged down at 16,000 g for 30 min, and increased that of smaller ones precipitated only after centrifugation at 100,000 g for 1 h. The lower the concentration of the depolymerized glia filament extract, the greater was the inhibition by α-SC of the polymerization. α-SC repressed polymerization of vimentin, the dominant component of glia filament. Vimentin polymerization was more strongly inhibited by α-SC than polymerization of glia filament was. The findings suggested that α-SC suppressed polymerization of glia filament through a direct action on vimentin and that the glia filament-associated proteins increased its structural stability in the presence of α-SC.     

The T→C mutation at position +96 of the untranslated region 3′ to the terminating codon of the β-globin gene is a rare polymorphism that does not cause a β-thalassemia as previously ascribed

We have observed a TC mutation at position +96 of the untranslated region 3 to the terminating codon of the -globin gene in members of two Czech families and one black family. Data from initial studies suggested that this change was the cause of a -thalassemia, but continued analyses have provided convincing evidence that this mutation is a simple polymorphism.     

Gibberellin A3 and Abscisic Acid Cause the Reorientation of Cortical Microtubules in Epicotyl Cells of the Decapitated Dwarf Pea

To determine whether or not the changes in the orientation ofmicrotubules (MTs) that are induced by GA₃ and ABA result fromchanges in the rate of epicotyl elongation caused by these hormones,we examined the effects of GA₃ and ABA on the orientation ofMTs in epidermal cells of decapitated epicotyls of the dwarfpea (Pisum sativum cv. Little Marvel), in which neither GA₃nor ABA causes changes in the rate of epicotyl elongation. Cuttings taken from GA₃-pretreated seedlings were decapitatedand treated with ABA. ABA eliminated the GA₃-induced predominanceof transverse MTs and treatment with ABA resulted in a predominanceof longitudinal MTs in the decapitated cuttings. However, ABAdid not reduce the rate of epicotyl elongation in these samples.Cuttings taken from ABA-pretreated seedlings were decapitatedand treated with GA₃. GA₃ caused the orientation of MTs to changefrom longitudinal to transverse in the decapitated cuttings.However, GA₃ had no promotive effect on elongation of theseepicotyls. The results indicate that both ABA and GA₃ have the abilityto change the orientation of MTs by mechanisms that do not involvechanges in the rate of cell elongation. (Received August 18, 1992; Accepted January 18, 1993)