Fucosyl-GM1a, an endoglycoceramidase-resistant ganglioside of porcine brain

The use of bovine brain has been prohibited in many countries because of the world-wide prevalence of mad cow disease, and thus porcine brain is expected to be a new source for the preparation of gangliosides. Here, we report the presence of a ganglioside in porcine brain which is strongly resistant to hydrolysis by endoglycoceramidase, an enzyme capable of cleaving the glycosidic linkage between oligosaccharides and ceramides of various glycosphingolipids. Five major gangliosides (designated PBG-1, 2, 3, 4, 5) were extracted from porcine brain by Folch's partition, followed by mild alkaline hydrolysis and PBA column chromatography. We found that PBG-2, but not the others, was strongly resistant to hydrolysis by the enzyme. After the purification of PBG-2 with Q-Sepharose, Silica gel 60 and Prosep-PB chromatographies, the structure of PBG-2 was determined by GC, GC-MS, FAB-MS and NMR spectroscopy as Fucalpha1-2Galbeta1-3GalNAcbeta1-4(NeuAcalpha2-3)Galbeta1-4Glcbeta1-1'Cer (fucosyl-GM1a). The ceramide was mainly composed of C18:0 and C20:0 fatty acids and d18:1 and d20:1 sphingoid bases. The apparent kcat/Km for fucosyl-GM1a was found to be 30 times lower than that for GM1a, indicating that terminal fucosylation makes GM1a resistant to hydrolysis by the enzyme. This report indicates the usefulness of endoglycoceramidase to prepare fucosyl-GM1a from porcine brain.     

Complete genome sequence of Sphingobium sp. strain SYK-6, a degrader of lignin-derived biaryls and monoaryls

Sphingobium sp. strain SYK-6 is able to grow on an extensive variety of lignin-derived biaryls and monoaryls, and the catabolic genes for these compounds are useful for the production of industrially valuable metabolites from lignin. Here we report the complete nucleotide sequence of the SYK-6 genome which consists of the 4,199,332-bp-long chromosome and the 148,801-bp-long plasmid.     

Solution structure of paralytic peptide of silkworm,Bombyx mori

Paralytic peptide of Bombyx mori (BmPP) is one of the multifunctional ENF-peptides; the name of “ENF” is the consensus N-terminal amino acid sequence of the family peptides. We revealed that BmPP significantly possesses growth-blocking activity and plasmatocyte-spreading activity and that its activity profiles are different from those of another ENF-family peptide, namely, the growth-blocking peptide of Pseudaletia separata (PsGBP). We also determined the NMR structures of BmPP and PsGBP under the same conditions, which revealed the structural differences of the first and second β-turn regions between the two peptides. On the basis of our results, it can be considered that the tertiary structural difference in these peptides may cause their different profiles of growth-blocking activity.     

IL-1 beta breaks tolerance through expansion of CD25+ effector T cells

IL-1 is a key proinflammatory driver of several autoimmune diseases including juvenile inflammatory arthritis, diseases with mutations in the NALP/cryopyrin complex and Crohn's disease, and is genetically or clinically associated with many others. IL-1 is a pleiotropic proinflammatory cytokine; however the mechanisms by which increased IL-1 signaling promotes autoreactive T cell activity are not clear. Here we show that autoimmune-prone NOD and IL-1 receptor antagonist-deficient C57BL/6 mice both produce high levels of IL-1, which drives autoreactive effector cell expansion. IL-1beta drives proliferation and cytokine production by CD4(+)CD25(+)FoxP3(-) effector/memory T cells, attenuates CD4(+)CD25(+)FoxP3(+) regulatory T cell function, and allows escape of CD4(+)CD25(-) autoreactive effectors from suppression. Thus, inflammation or constitutive overexpression of IL-1beta in a genetically predisposed host can promote autoreactive effector T cell expansion and function, which attenuates the ability of regulatory T cells to maintain tolerance to self.     

Insect Cytokine Paralytic Peptide (PP) Induces Cellular and Humoral Immune Responses in the Silkworm Bombyx mori

In the blood (hemolymph) of the silkworm Bombyx mori, the insect cytokine paralytic peptide (PP) is converted from an inactive precursor to an active form in response to the cell wall components of microorganisms and contributes to silkworm resistance to infection. To investigate the molecular mechanism underlying the up-regulation of host resistance induced by PP, we performed an oligonucleotide microarray analysis on RNA of blood cells (hemocytes) and fat body tissues of silkworm larvae injected with active PP. Expression levels of a large number of immune-related genes increased rapidly within 3 h after injecting active PP, including phagocytosis-related genes such as tetraspanin E, actin A1, and ced-6 in hemocytes, and antimicrobial peptide genes cecropin A and moricin in the fat body. Active PP promoted in vitro and in vivo phagocytosis of Staphyloccocus aureus by the hemocytes. Moreover, active PP induced in vivo phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) in the fat body. Pretreatment of silkworm larvae with ML3403, a pharmacologic p38 MAPK inhibitor, suppressed the PP-dependent induction of cecropin A and moricin genes in the fat body. Injection of active PP delayed the killing of silkworm larvae by S. aureus, whereas its effect was abolished by preinjection of the p38 MAPK inhibitor, suggesting that p38 MAPK activation is required for PP-dependent defensive responses. These findings suggest that PP acts on multiple tissues in silkworm larvae and acutely activates cellular and humoral immune responses, leading to host protection against infection.     

Coating of a surface with 2-methacryloyloxyethyl phosphorylcholine (MPC) co-polymer significantly reduces retention of human pathogenic microorganisms

The present study compares the retention of four species that are often isolated in association with biomedical device-related infections - Staphylococcus aureus, Streptococcus mutans, Pseudomonas aeruginosa, and Candida albicans - to three different surfaces. All four bacterial species were found to bind significantly less well to MPC-coated surfaces than to non-coated surfaces. We attribute this effect to the "superhydrophilicity" of MPC-coated surfaces, whereas hydrophobic surfaces are well known to reduce bacterial retention and thus to inhibit a crucial step in the formation of bacterial biofilms that lead to biomedical device-related infections and complications.     

Identification of a gene encoding a tetrathionate hydrolase in Acidithiobacillus ferrooxidans

Tetrathionate is one of the most important intermediates in dissimilatory sulfur oxidation and can itself be utilized as a sole energy source by some sulfur-oxidizing microorganisms. Tetrathionate hydrolase (4THase) plays a significant role in tetrathionate oxidation and should catalyze the initial step in the oxidative dissimilation when sulfur-oxidizing bacteria are grown on tetrathionate. 4THase activity was detected in tetrathionate-grown Acidithiobacillus ferrooxidans ATCC 23270 cells but not in iron-grown cells. A 4THase having a dimeric structure of identical 50kDa polypeptides was purified from tetrathionate-grown cells. The 4THase showed the maximum activity at pH 3.0 and high stability under acidic conditions. An open reading frame (ORF) encoding the N-terminal amino acid sequence of the purified 4THase was identified by a BLAST search using the database for the A. ferrooxidans ATCC 23270 genome. Heterologous expression of the gene in Escherichia coli resulted in the formation of inclusion bodies of the protein in an inactive form. Antisera against the recombinant protein clearly recognized the purified native 4THase, indicating that the ORF encoded the 4THase.