Induction of diabetes by PolyI:C and anti-RT6.1 antibody treatment in DR-BB rats.

To determine whether environmental factors could affect the incidence of diabetes in RT6.1+ lymphocytes-depleted diabetes resistant (DR) BB rats, we tested polyinosinic-polycytidylic acid (Poly I:C), as an immune activator, in conjunction with anti-RT6.1 antibody in DR-BB rats which were bred in a specific pathogen free (SPF) condition. Diabetes was induced by the combined administration of poly I:C and anti-RT6.1 antibody. The use of poly I:C or anti-RT6.1 antibody alone did not cause diabetes. These results suggest that RT6.1+ T lymphocytes regulate autoimmune diabetes and that non-specific immune activation caused by environmental factors plays a key role in inducing diabetes in DR-BB rats.     

Synthesis of 2-deoxy-4-O-phosphono-3-O-tetradecanoyl-2-[(3R)- and (3S)-3-tetradecanoyloxytetradecanamido]-D-glucose: a diastereoisomeric pair of 4-O-phosphono-D-glucosamine derivatives (GLA-27) related to bacterial lipid A

The diastereoisomeric, 4-O-phosphono-D-glucosamine derivatives named in the title have been synthesized, starting from benzyl 2-amino-2-deoxy-4,6-O-isopropylidene-beta-D-glucopyranoside and (3RS)-3-hydroxytetradecanoic acid.     

A Simple,Preparative Procedure for N 3-Anisoyluridine and O 6-Diphenylcarbamoylguanosine 2′-O-(Tetrahydropyran-2-YL) Derivatives via The Corresponding 3′,5′-Dibenzoates

Abstract

3′,5′-Di-O-benzoyl-2′-O-(tetrahydropyran-2-yl)uridine and 3′,5′ -di-O-benzoyl-N ²-isobutyryl-2′-O-(tetrahydropyran-2-yl)guanosine are converted into-N ³-anisoyl-2′-O-(tetrahydropyran-2-yl)uridine (less and more polar diastereoisomers in 37% and 42% yields, respectively) and O ⁶-diphenyl carbamoylN ²-isobutyryl-2′-O-(tetrahydropyran-2-yl)- guanosine (less and more polar diastereoisomers in 15% and 59% yields, respectively), respectively, by N ³-anisoylation and O ⁶-diphenylcarbamoylation, followed by 3′,5′-di-O-debenzoylation.     

Antiparallel pleated beta-sheets observed in crystal structures of N,N-bis(trichloroacetyl) and N,N-bis(m-bromobenzoyl) gramicidin S.

Despite intensive efforts, the structures of gramicidin S (GS) [cyclo(-Val-Orn-Leu-d-Phe-Pro-)(2)] and its analogues have not been elucidated by the X-ray diffraction method, except for the GS-urea complex (Hull et al., Nature 275, 206-207, 1978; Tishchenko et al., Acta Cryst. D53, 151-159, 1997). We focused on the acetylation of GS to obtain suitable crystals for X-ray diffraction. The amino groups of Orn residues were capped with trichloroacetic and m-bromobenzoic acids. Both trichloroacetyl and m-bromobenzoyl GSs (TcGS and BzGS, respectively) are hydrophobic and their properties are similar to those of acetyl-GS (AcGS). Although it is well known that AcGS yields hexagonal crystals, TcGS and BzGS yield monoclinic and orthorhombic crystals in aqueous dimethylformamide solution, respectively. Their cell volumes were approximately one-fourth or one-eighth of the hexagonal cell volume. The crystal structures of TcGS and BzGS were determined as the first examples of acetylated GS analogues: TcGS, C(64)H(90)N(12)O(12)Cl(6). 3(C(3)H(7)NO), M(r) = 1651.47, monoclinic, P2(1), a = 15.4366(6) A, b = 18.5312(4) A, c = 16.4774(6) A, beta = 14.160(2) degrees, V = 4300.6(2) A(3), Z = 2; and BzGS, C(64)H(98)N(12)O(12)Br(2). 1.54(H(2)O), M(r) = 1535.21, orthorhombic, P2(1)2(1)2(1), a = 16.748(10) A, b = 18.834(5) A, c = 28.558(10) A, V = 9008(7) A(3), Z = 4. Both these peptide molecules formed an antiparallel pleated beta-sheet, and pseudo twofold symmetries existed in the repeated sequence. beta-Turns formed at the fragments of d-Phe-Pro were classified into type II' based on their characteristics. The peptide conformations of TcGS and BzGS were similar to each other, and these structural features agreed with those of structures proposed by the previous studies.     

ASC-mediated NF-kappaB activation leading to interleukin-8 production requires caspase-8 and is inhibited by CLARP

ASC is an adaptor molecule that mediates apoptotic and inflammatory signals from several Apaf-1-like molecules, including CARD12/Ipaf, cryopyrin/PYPAF1, PYPAF5, PYPAF7, and NALP1. To characterize the signaling pathway mediated by ASC, we established cell lines in which muramyl dipeptide, the bacterial component recognized by another Apaf-1-like molecule, Nod2, induced an interaction between a CARD12-Nod2 chimeric protein and ASC, and elicited cell autonomous NF-kappaB activation. This response required caspase-8, and was suppressed by CLARP/FLIP, an inhibitor of caspase-8. The catalytic activity of caspase-8 was required for the ASC-mediated NF-kappaB activation when caspase-8 was expressed at an endogenous level, although it was not essential when caspase-8 was overexpressed. In contrast, FADD, the adaptor protein linking Fas and caspase-8, was not required for this response. Consistently, ASC recruited caspase-8 and CLARP but not FADD and Nod2 to its speck-like aggregates in cells. Finally, muramyl dipeptide induced interleukin-8 production in MAIL8 cells. These results are the first to indicate that caspase-8 plays an important role in the ASC-mediated NF-kappaB activation, and that the ASC-mediated NF-kappaB activation actually induces physiologically relevant gene expression.     

Brain 5-HT synthesis in the Flinders Sensitive Line rat model of depression: an autoradiographic study

Alterations of serotonin (5-HT) levels and serotonergic transmission have been associated with depression. 5-HT synthesis is an important factor of serotonergic neurotransmission that may also be altered in depression. Many studies of the relationships between brain serotonergic functions and affective disorders have been performed in different animal models. In this study, brain regional 5-HT synthesis was examined using the alpha-[(14)C]methyl-L-tryptophan (alpha-MTrp) autoradiographic method in a genetic rat model of depression, Flinders Sensitive Line (FSL) rats, and was compared to both the Flinders Resistant Line (FRL) rats and the control Sprague-Dawley (SD) rats. The plasma concentration of free tryptophan in the FSL rats was not significantly different (p > 0.05; ANOVA and post-hoc Bonferroni correction) when compared to that of the FRL and SD rats. The FSL rats had significantly lower 5-HT synthesis (one sample two-tailed t-test on the ratio) than both the FRL and SD rats (the mean ratios were 0.78 +/- 0.12 and 0.73 +/- 0.15, respectively). Overall, the 5-HT synthesis in the FRL rats was not significantly different (p > 0.05) from that in the SD rats (one sample two-tailed t-test on the ratio and the mean ratio was 0.93 +/- 0.13). Studies of individual brain structures, such as the raphe nuclei and their many terminal areas, including the nucleus accumbens, cingulate and frontal cortex, hippocampus, amygdala, and thalamus revealed significant reductions (typically 25-50%) in 5-HT synthesis in the FSL rats compared to the non-depressive FRL and SD rats. These results suggest that significantly reduced 5-HT synthesis in the raphe nuclei and limbic areas in FSL rats may contribute to their depressive features.     

Plant lectin can target receptors containing sialic Acid, exemplified by podoplanin, to inhibit transformed cell growth and migration

Cancer is a leading cause of death of men and women worldwide. Tumor cell motility contributes to metastatic invasion that causes the vast majority of cancer deaths. Extracellular receptors modified by α2,3-sialic acids that promote this motility can serve as ideal chemotherapeutic targets. For example, the extracellular domain of the mucin receptor podoplanin (PDPN) is highly O-glycosylated with α2,3-sialic acid linked to galactose. PDPN is activated by endogenous ligands to induce tumor cell motility and metastasis. Dietary lectins that target proteins containing α2,3-sialic acid inhibit tumor cell growth. However, anti-cancer lectins that have been examined thus far target receptors that have not been identified. We report here that a lectin from the seeds of Maackia amurensis (MASL) with affinity for O-linked carbohydrate chains containing sialic acid targets PDPN to inhibit transformed cell growth and motility at nanomolar concentrations. Interestingly, the biological activity of this lectin survives gastrointestinal proteolysis and enters the cardiovascular system to inhibit melanoma cell growth, migration, and tumorigenesis. These studies demonstrate how lectins may be used to help develop dietary agents that target specific receptors to combat malignant cell growth.     

Revision of the theory of phototropism in plants: a new interpretation of a classical experiment

Went's classical experiment on the diffusion of auxin activity from unilaterally illuminated oat coleoptile tips (Went 1928), was repeated as precisely as possible. In agreement with Went's data with theAvena curvature assay, the agar blocks from the illuminated side of oat (Avena sativa L. cv. Victory) coleoptile tips had, on an average, 38% of the auxin activity of those from the shaded side. However, determination of the absolute amounts of indole-3-acetic acid (IAA) in the agar blocks, using a physicochemical assay following purification, showed that the IAA was evenly distributed in the blocks from the illuminated and shaded sides. In the blocks from the shaded and dark-control halves the amounts of IAA were 2.5 times higher than the auxin activity measured by theAvena curvature test, and in those from the illuminated half even 7 times higher. Chromatography of the diffusates prior to theAvena curvature test demonstrated that the amounts of two growth inhibitors, especially of the more polar one, were significantly higher in the agar blocks from the illuminated side than in those from the shaded side and the dark control. These results show that the basic experiment from which the Cholodny-Went theory was derived, does not justify this theory. The data rather indicate that phototropism is caused by the light-induced, local accumulation of growth inhibitors against a background of even auxin distribution, the diffusion of auxin being unaffected.Abbreviation IAA indole-3-acetic acid     

Spectroscopic analysis of the dark relaxation process of a photocycle in a sensor of blue light using FAD (BLUF) protein Slr1694 of the cyanobacterium Synechocystis sp. PCC6803

Slr1694 is a BLUF (sensor of blue light using flavin adenine dinucleotide) protein and a putative photoreceptor in the cyanobacterium Synechocystis sp. PCC6803. Illumination of Slr1694 induced a signaling light state concurrent with a red shift in the UV-visible absorption of flavin, and formation of the bands from flavin and apo-protein in the light-minus-dark Fourier transform infrared (FTIR) difference spectrum. Replacement of Tyr8 with phenylalanine abolished these changes. The light state relaxed to the ground dark state, during which the FTIR bands decayed monophasically. These bands were classifiable into three groups according to their decay rates. The C4=O stretching bands of a flavin isoalloxazine ring had the highest decay rate, which corresponded to that of the absorption red shift. The result indicated that the hydrogen bonding at C4=O is responsible for the UV-visible red shift, consistent with the results of density functional calculation. All FTIR bands and the red shift decayed at the same slower rate in deuterated Slr1694. These results indicated that the dark relaxation from the light state is limited by proton transfer. In contrast, a constrained light state formed under dehydrated conditions decayed much more slowly with no deuteration effects. A photocycle mechanism involving the proton transfer was proposed.