Involvement of Cell Wall-Bound Diferulic Acid in Light-Induced Decrease in Growth Rate and Cell Wall Extensibility of Oryza Coleoptiles

Irradiation of white fluorescent light (5 W m^–2) inhibitedthe growth of Oryza coleoptiles. Light irradiation increasedstress-relaxation parameters of coleoptile cell walls, minimumstressrelaxationtime and relaxation rate, and decreased cellwall extensibility (strain/load). Under light conditions, thecontents of ferulic and diferulic acids ester-linked to thehemicellulosic arabinose residue in cell walls increased andcorrelated with the modification of the cell wall mechanicalproperties. These results suggest that light irradiation enhancesthe formation of diferulic acid bridges in hemicelluloses, makingcell walls mechanically rigid and thus inhibits cell elongationin rice coleoptiles. Also, irrespective of coleoptile age orthe presence of light, the ratio of diferulic acid to ferulicacid was almost constant, suggesting that the rate limitingstep in the formation of diferulic acid bridges in Oryza cellwalls is in the step of feruloylation. (Received September 24, 1991; Accepted December 3, 1991)     

Conformational Change of a Natto Mucin in Solution

The mucin obtained from a natto sample was found to be composed of 58 % of γ-polyglutamic acid and 40% of polysaccharide. The ratio of l- and d-glutamic acid was determined to be 58:42 using l-glutamic acid decarboxylase. The weight- and z-average molecular weight were 2.08 × 10⁵ and 2.22 × 10⁵, respectively. The distribution curve of the sedimentation coefficient showed a small heterogeneity. The mucin molecule was considered to be randomly coiled at pH 5.0 ~ 8.8 and to be a rod-like molecule in the lower pH region.     

Purification and Chemical Analysis of Microbial Cell Flocculant Produced by Aspergillus sojae AJ7002

A bio-flocculant was isolated from the culture broth of Asp. sojae AJ 7002. It was partially purified by acetone or ethanol precipitation, by ion-exchange and gel chromatography, and by dialysis. The isolated polymer possessed chemical characteristics of a poly-hexosamine and a protein. Glucosamine and galactosamine were not acetylated. The flocculant contained 2-ketogluconic acid, but sulfur or phosphorus was not detected. This flocculant was thermo-stable and its activity varied with pH. It was suggested that the hexosamine moiety in the polymer played a major role in bio-flocculation, assisted by protein portion in enlargement of the molecular weight of the flocculant, and by 2-ketogluconic acid in endowing it with amphoteric character.     

Unique T Cells with Unconventional Cytokine Profiles Induced in the Livers of Mice during Schistosoma mansoni Infection

During infection with Schistosoma, serious hepatic disorders are induced in the host. The liver possesses unique immune systems composed of specialized cells that differ from those of other immune competent organs or tissues. Host immune responses change dramatically during Schistosoma mansoni infection; in the early phase, Th1-related responses are induced, whereas during the late phase Th2 reactions dominate. Here, we describe unique T cell populations induced in the liver of mice during the period between Th1- and Th2-phases, which we term the transition phase. During this phase, varieties of immune cells including T lymphocytes increase in the liver. Subsets of CD4⁺ T cells exhibit unique cytokine production profiles, simultaneously producing both IFN-γ and IL-13 or both IFN-γ and IL-4. Furthermore, cells triply positive for IFN-γ, IL-13 and IL-4 also expand in the S. mansoni-infected liver. The induction of these unique cell populations does not occur in the spleen, indicating it is a phenomenon specific to the liver. In single hepatic CD4⁺ T cells showing the unique cytokine profiles, both T-bet and GATA-3 are expressed. Thus, our studies show that S. mansoni infection triggers the induction of hepatic T cell subsets with unique cytokine profiles.     

Properties of Nucleoside Phosphorylase from Enterobacter aerogenes

The properties of uridine Phosphorylase (UPase) and purine nucleoside Phosphorylase (PNPase) at high temperature were investigated. Both enzymes were found to be distributed in a wide range of bacteria and were partially purified from Enterobacter aerogenes AJ 11125 by heat treatment, ammonium sulfate fractionation and column chromatographies onDEAE-cellulose and Sephadex G-150. The UPase was purified 109-fold, and it showed an optimum pH of 8.5 and optimum temperature of 65°C, and activity toward uridine, 2′-deoxyuridine, thymidine and uracil arabinoside but not cytidine. The Km values of UPase for uridine were 0.7 mm at 40°C and 1.8 mm at 60°C. The PNPase was purified 83-fold, and it showed an optimum pH of 6.8 and optimum temperature of 60°C, and significant activity toward purine arabinosides as well as purine ribosides. The Km values of PNPase for inosine were 0.8 mm at 40°C and 2.2 mm at 60°C.     

Pdx-1 and Ptf1a concurrently determine fate specification of pancreatic multipotent progenitor cells

The pancreas is derived from a pool of multipotent progenitor cells (MPCs) that co-express Pdx-1 and Ptf1a. To more precisely define how the individual and combined loss of Pdx-1 and Ptf1a affects pancreatic MPC specification and differentiation we derived and studied mice bearing a novel Ptf1a^YFP allele. While the expression of Pdx-1 and Ptf1a in pancreatic MPCs coincides between E9.5 and 12.5 the developmental phenotypes of Pdx-1 null and Pdx-1; Ptf1a double null mice are indistinguishable, and an early pancreatic bud is formed in both cases. This finding indicates that Pdx-1 is required in the foregut endoderm prior to Ptf1a for pancreatic MPC specification. We also found that Ptf1a is neither required for specification of Ngn3-positive endocrine progenitors nor differentiation of mature β-cells. In the absence of Pdx-1 Ngn3-positive cells were not observed after E9.5. Thus, in contrast to the deletion of Ptf1a, the loss of Pdx-1 precludes the sustained Ngn3-based derivation of endocrine progenitors from pancreatic MPCs. Taken together, these studies indicate that Pdx-1 and Ptf1a have distinct but interdependent functions during pancreatic MPC specification.     

Structural characterization of lipid A component of Erwinia carotovora lipopolysaccharide

The chemical structure of the lipid A component of lipopolysaccharide excreted into the liquid medium by the plant pathogenic enterobacterium Erwinia carotovora FERM P-7576 was characterized. It consists of a -1, 6-linked glucosamine disaccharide which carries ester-and amide-bound fatty acids and phosphate similar to the lipid A from other gram-negative bacteria. The lipid A preparation was not uniform in the number and composition of the fatty acids linked to the disaccharide. Four prominent lipids A were involved, they were composed of five to seven residues of fatty acid. Among them the major component was hexa-acyl lipid A, in which the hydroxyl group at position 3 and the amino group of the non-reducing glucosamine unit carry 3-dodecanoyl-oxytetradecanoyl residues. Positions 2 and 3 of the reducing glucosamine unit were substituted by 3-hydroxytetradecanoic acid. In the hepta-acyl lipid A, an additional hexadecanoic acid was linked to the hydroxyl group of the 3-hydroxytetradecanoyl residue at position 2 of the hexa-acyl lipid A. Two penta-acyl lipids A were the homologs of the hexa-acyl lipid A with decreasing acylation. Dodecanoic acid was missing from one, and 3-hydroxytetradecanoic acid from another. 3-Dodecanoyloxytetradecanoyl residue at position 3 differentiates E. carotovora lipid A from that of other gram-negative bacteria.Abbreviations LPS lipopolysaccharide - GlcN glucosamine - KDO 3-deoxy-d-manno-octulosonic acid - FAB-MS fast atom bombardment mass spectrometry - u atomic mass unit     

Kinetic analyses for bindings of concanavalin A to dispersed and condensed mannose surfaces on a quartz crystal microbalance

A biotinylated mannotriose (Man3-bio) was dispersively immobilized in the matrix of biotinylated lactose (Gal-Glc-bio) on a streptavidin-covered, 27-MHz quartz crystal microbalance (QCM), and binding kinetics of concanavalin A (Con A) to Man3-bio in the Gal-Glc-bio matrix could be obtained from frequency decreases (mass increases) of the QCM. Association constants (K_a) and binding and dissociation rate constants (k_on and k_off) could be determined separately as the 1:1 and 1:2 bindings of Con A to Man3-bio on the surface. When Man3-bio was immobilized with content of 1 to 5 mol% in the matrix, the 1:1 binding of Con A to Man3-bio was obtained as K_a = (4 ± 1) × 10⁶ M⁻¹, k_on = (4 ± 1) × 10⁴ M⁻¹ s⁻¹, and k_off = (12 ± 2) × 10^–3 s⁻¹. On the contrary, when Man3-bio was immobilized with content of 20 to 100 mol% in the matrix, the 1:2 binding of Con A to Man3-bio was obtained as K_a = (14 ± 2) × 10⁶ M⁻¹, k_on = (14 ± 2) × 10⁴ M⁻¹ s⁻¹, and k_off = (7 ± 2) × 10^–3 s⁻¹. Thus, K_a for the 1:2 binding was 10 times larger than that for the 1:1 binding, with a three times larger binding rate constant (k_on) and a three times smaller dissociation rate constant (k_off). This is the first example to obtain separate kinetic parameters for the 1:1 and 1:2 bindings of lectins to carbohydrates on the surface.     

Effect of Caffeine-Containing Beverage Consumption on Serum Alanine Aminotransferase Levels in Patients with Chronic Hepatitis C Virus Infection: A Hospital-Based Cohort Study

Introduction

To date, there have been no prospective studies examining the effect of coffee consumption on serum alanine aminotransferase (ALT) level among individuals infected with the hepatitis C virus (HCV). We conducted a hospital-based cohort study among patients with chronic HCV infection to assess an association between baseline coffee consumption and subsequent ALT levels for 12 months.

Materials and Methods

From 1 August 2005 to 31 July 2006, total 376 HCV-RNA positive patients were recruited. A baseline questionnaire elicited information on the frequency of coffee consumption and other caffeine-containing beverages. ALT level as a study outcome was followed through the patients’ medical records during 12 months. The association between baseline beverage consumption and subsequent ALT levels was evaluated separately among patients with baseline ALT levels within normal range (≤45 IU/L) and among those with higher ALT levels (>45 IU/L).

Results

Among 229 patients with baseline ALT levels within normal range, 186 (81%) retained normal ALT levels at 12 months after recruitment. Daily drinkers of filtered coffee were three times more likely to preserve a normal ALT level than non-drinkers (OR=2.74; P=0.037). However, decaffeinated coffee drinkers had a somewhat inverse effect for sustained normal ALT levels, with marginal significance (OR=0.26; P=0.076). In addition, among 147 patients with higher baseline ALT levels, 39 patients (27%) had ALT reductions of ≥20 IU/L at 12 months after recruitment. Daily drinkers of filtered coffee had a significantly increased OR for ALT reduction (OR=3.79; P=0.034). However, in decaffeinated coffee drinkers, OR could not be calculated because no patients had ALT reduction.

Conclusion

Among patients with chronic HCV infection, daily consumption of filtered coffee may have a beneficial effect on the stabilization of ALT levels.