Conversion of pyridylamino sugar chains to corresponding reducing sugar chains

Pyridylamino sugar chains were converted to the corresponding reducing sugar chains by first converting them to 1-amino-1-deoxy derivatives using the method previously reported [S. Hase, J. Biochem. 112, 266-268 (1992)] and then converting the products to the corresponding reducing sugar chains using the Sommlet reaction. The reaction conditions were optimized so as to obtain the maximal product yield using 1-amino-1-deoxylactose and 1-amino-1-deoxy-N-acetylglucosamine. When the established procedure was successively applied to pyridylamino high-mannose and complex-type sugar chains, the corresponding reducing sugar chains were obtained in yields of 30%.     

Ubiquitin in chains

The ubiquitin-proteasome system fulfills an essential function in eukaryotes by controlling the levels of crucial intracellular regulatory proteins. In this system, a specific type of polyubiquitin chain acts as the proximal signal for targeting substrates to 26S proteasomes for degradation. Recent results have revealed important determinants of polyubiquitin-chain recognition by proteasomes, helping to explain the biological rationale behind this novel signaling mechanism.     

Linear polyubiquitin chains

The ubiquitin conjugation system regulates a wide variety of biological phenomena, including protein degradation and signal transduction, by regulating protein function via polyubiquitin conjugation in most cases. Several types of polyubiquitin chains exist in cells, and the type of polyubiquitin chain conjugated to a protein seems to determine how that protein is regulated. We identified a novel linear polyubiquitin chain and the ubiquitin-protein ligase complex that assembles it, designated LUBAC. Both were shown to have crucial roles in the canonical NFκB activation pathway. This year, three groups, including our laboratory, identified SHARPIN as a new subunit of LUBAC. Of great interest, Sharpin was identified as a causative gene of chronic proliferative dermatitis in mice (cpdm), which is characterized by numerous inflammatory symptoms including chronic dermatitis, arthritis and immune disorders. Deletion of SHARPIN drastically reduces the amount of LUBAC and attenuates signal-induced NFκB activation. The pleomorphic symptoms of cpdm mice suggest that LUBAC-mediated NFκB activation may play critical roles in mammals and be involved in various disorders. A forward look into the linear polyubiquitin research is also discussed.     

Monitoring of trophic chains

In the paper simple trophic chains of the type resource-producer-primary consumer are considered. For an analysis of the dynamic state monitoring of this system, the concept of observability of mathematical systems theory is proposed. Using a linearization method of non-linear observation systems, biologically interpretable sufficient conditions are obtained to guarantee local observability. The latter means that based on the dynamic observation of a single component, the state of the whole system can be uniquely recovered, at least near a positive equilibrium.     

Stories about acyl chains

The effect of dietary polyunsaturated fatty acids and alpha-tocopherol supplementation on erythrocyte lipid peroxidation and immunocompetent cells in mice was studied comparatively using seven dietary oils (15% oil/diet, w/w) including fish oil rich in eicosapentaenoic acid (EPA, 20:5, n-3) and docosahexaenoic acid (DHA, 22:6, n-3). A 43% increase in spleen weight, about twice as many spleen cells and no change in the subpopulations of spleen cells, as well as a significant depression of mitogen-induced blastogenesis of both T and B cells in the spleen were observed in mice fed fish oil for 30 days in comparison with soybean oil diet-fed mice. In the fish oil diet-fed mice, membranous lipid hydroperoxide (hydroperoxides of phosphatidylcholine and phosphatidylethanolamine) accumulation as a marker of oxidative senescence in red blood cells (RBC) was 2.7-3.5 times higher than that in mice fed soybean oil, although there was no difference in the plasma phosphatidylcholine hydroperoxide concentration. In spite of the supplementation of alpha-tocopherol to up to 10 times the level in the basal diet, the degeneration of spleen cells and the stimulated oxidative senescence of RBC found by the fish oil feeding could not be prevented. The results suggest that oral intake of excess polyunsaturated fatty acids, i.e. EPA and DHA, in a fish oil diet can lead to acceleration of membrane lipid peroxidation resulting in RBC senescence linked to the lowering of immune response of spleen cells, and that supplementation of alpha-tocopherol as antioxidant does not always effectively prevent such oxidative degeneration as observed in spleen cells and RBC in vivo.     

Living macrophages phosphorylate the 20,000 dalton light chains and heavy chains of myosin

Brief incubation of rabbit alveolar macrophages in medium containing ³²Pi results in the incorporation of radioactivity into the 20 KD light chains and into the 220 KD heavy chains of myosin. Phosphorylation of the heavy chain is mediated by a kinase that is probably not myosin light chain kinase. Limited proteolysis of the phosphorylated myosin shows that radioactivity is associated with the rod portion of the heavy chain.     

Mouse pre-B cells synthesize and secrete mu heavy chains but not light chains

The immunoglobulins produced by the earliest recognizable B cell precursors (pre-B cells) were characterized in the mouse and human. Immunofluorescent analysis revealed no evidence of surface IgM components, and only mu heavy chains could be detected intracytoplasmically in pre-B cells. Surface IgM components could not be isolated from intact fetal liver cells that lacked sIgM+ B lymphocytes but possessed pre-B cells. Pre-B cells were shown to synthesize and secrete mu heavy chains but not light chains by immunochemical analysis. These mu chains constituted less than 0.01% of TCA precipitable protein synthesized and secreted by fetal liver cells during an 8 hr labelling period. Migration of both intracellular and secreted mu chains on SDS-PAGE suggested that they were smaller than mu chains secreted by mouse and human plasmacytomas. These data indicate that mu chain synthesis precedes light chain expression during B cell ontogeny and suggest a new role for pre-B cells in the generation and expression of a diverse immunoglobulin repertoire.     

Phosphorylation of vertebrate nonmuscle and smooth muscle myosin heavy chains and light chains

In this article we review the various amino acids present in vertebrate nonmuscle and smooth muscle myosin that can undergo phosphorylation. The sites for phosphorylation in the 20 kD myosin light chain include serine-19 and threonine-18 which are substrates for myosin light chain kinase and serine-1 and/or-2 and threonine-9 which are substrates for protein kinase C. The sites in vertebrate smooth muscle and nonmuscle myosin heavy chains that can be phosphorylated by protein kinase C and casein kinase II are also summarized.Original data indicating that treatment of human T-lymphocytes (Jurkat cell line) with phorbol 12-myristate 13-acetate results in phosphorylation of both the 20 kD myosin light chain as well as the 200 kD myosin heavy chain is presented. We identified the amino acids phosphorylated in the human T-lymphocytes myosin light chains as serine-1 or serine-2 and in the myosin heavy chains as serine-1917 by 1-dimensional isoelectric focusing of tryptic phosphopeptides. Untreated T-lymphocytes contain phosphate in the serine-19 residue of teh myosin light chain and in a residue tentatively identified as serine-1944 in the myosin heavy chain.Abbreviations MLC myosin light chain - MHC myosin heavy chain - Tris tris(hydroxymethyl)aminomethane - EGTA [ethylenebis(oxyethylenenitrilo)]tetraacetic acid - EDTA ethylenediaminetetraacetate - TPCK N-tosyl-L-phenylalanine chloromethyl ketone - PMA phorbol 12-myristate 13-acetate     

Different asparagine-linked sugar chains on the two polypeptide chains of human chorionic gonadotropin

Human chorionic gonadotropin (hCG) purified from placenta, like urinary hCG, is shown to have the sialylated forms of three neutral oligosaccharides: Galβ1→4GlcNAcβ1→2Manα1→6(Galβ1→4GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAcβ1→4(Fucα1→6)GlcNAc (N-1), Galβ1→4GlcNAcβ1→2Manα1→6(Galβ1→4GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAcβ1→4GlcNAc (N-2) and Manα1→6(Galβ1→4GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAcβ1→4GlcNAc (N-3). Gel permeation chromatographic analysis of oligosaccharides released from α- and β-subunits of placental hCG has revealed that the α-subunit has one each of sialylated N-2 and N-3, while the β-subunit has one each of sialylated N-1 and N-2.     

Constructing side chains on near-native main chains for ab initio protein structure prediction

Is there value in constructing side chains while searching protein conformational space during an ab initio simulation? If so, what is the most computationally efficient method for constructing these side chains? To answer these questions, four published approaches were used to construct side chain conformations on a range of near-native main chains generated by ab initio protein structure prediction methods. The accuracy of these approaches was compared with a naive approach that selects the most frequently observed rotamer for a given amino acid to construct side chains. An all-atom conditional probability discriminatory function is useful at selecting conformations with overall low all-atom root mean square deviation (r.m.s.d.) and the discrimination improves on sets that are closer to the native conformation. In addition, the naive approach performs as well as more sophisticated methods in terms of the percentage of chi(1) angles built accurately and the all-atom r. m.s.d., between the native and near-native conformations. The results suggest that the naive method would be extremely useful for fast and efficient side chain construction on vast numbers of conformations for ab initio prediction of protein structure.     

A component of the fraction of porcine light chains structurally related to heavy chains

In the previous paper (Rejneket al., 1967) we described the fractionation of light chains (L) by Zn ions resulting in an accumulation of antigenic determinants of the heavy chain (H) in the Zn precipitate. Peptide maps of the obtained fractions of the L chains differ considerably from each other. Peptides of the L chains, the position of which corresponds within the experimental error to peptides of the H chain may be detected by comparing them with the peptide map of the H chains. The number of such peptides increases with qualitatively assayed accumulation of the component precipitated with anti-H serum during fractionation. The concentration of N-terminal glutamic acid, characteristic for the H chains increases at the same time.     

Developing sustainable food supply chains

This paper reviews the opportunities available for food businesses to encourage consumers to eat healthier and more nutritious diets, to invest in more sustainable manufacturing and distribution systems and to develop procurement systems based on more sustainable forms of agriculture. The important factors in developing more sustainable supply chains are identified as the type of supply chain involved and the individual business attitude to extending responsibility for product quality into social and environmental performance within their own supply chains. Interpersonal trust and working to standards are both important to build more sustainable local and many conserved food supply chains, but inadequate to transform mainstream agriculture and raw material supplies to the manufactured and commodity food markets. Cooperation among food manufacturers, retailers, NGOs, governmental and farmers' organizations is vital in order to raise standards for some supply chains and to enable farmers to adopt more sustainable agricultural practices.     

On chains of related sets

IfK is a partition of a setK which is partially ordered by the relationR andR is a collection of pairs of sets ofK such that the sets of each pair are related byR in the sense of Rashevsky, thenR is a relation which partially ordersK. Necessary and sufficient conditions thatK be a chain are obtained, and ifK is a chain under these conditions, it is shown thatK is unique.