The modifying effects of green tea polyphenols on acute colitis and inflammation-associated colon carcinogenesis in male ICR mice.

Reactive oxygen species (ROS) have been implicated as mediators of intestinal inflammation and carcinogenesis. Although green tea polyphenols (GTP) have anticancer property as antioxidants they also generate ROS in vitro. In this study, we investigated the modifying effects of GTP on dextran sulfate sodium (DSS)-induced acute colitis and on 1,2-dimethylhydrazine (DMH) and DSS-induced colon carcinogenesis in male ICR mice. At sacrifice after 6 days, the colon shortening induced by 2% DSS was unchanged by 0.1% and 0.25% GTP, but increased by 0.5% and 1% GTP-containing diet. The expression of interleukin-1beta and macrophage-migration inhibitory factor in the DSS + 0.1% GTP group were lower than the DSS alone group, whereas the expression levels were increased in the DSS + 0.5% GTP and DSS + 1% GTP groups when compared with the DSS alone group. In a subsequent experiment to determine the effects of 0.01-1% GTP on inflammation-associated colon carcinogenesis induced by DMH/DSS, 0.5 and 1% doses of GTP failed to prevent the development of multiple colon tumors, rather, they tended to increase it. Our results thus indicate that the modifying effects of GTP on DSS-induced acute colitis and DMH/DSS-induced colon carcinogenesis depends upon its dosage and the expression of proinflammatory cytokines

Effects of improved sodium uptake ability on grain yields of rice plants under low potassium supply

Sodium uptake is a factor that determines potassium use efficiency in plants as sodium can partially replace potassium in plant cells. Rice (Oryza sativa) roots usually exclude sodium but actively take it up when the plant is deficient in potassium. In rice roots, a sodium transporter OsHKT2;1 mediates active sodium uptake. We previously revealed that variation in the expression of OsHKT2;1 underlies the variation in sodium accumulation between a low-sodium-accumulating indica cultivar, IR64, and a high-sodium-accumulating japonica cultivar, Koshihikari. In the present study, we evaluated IR64 and its near-isogenic line IR64-K carrying OsHKT2;1 and neighboring genes inherited from Koshihikari for grain yield. IR64-K had a greater average grain yield and harvest index than IR64 in a pot culture experiment with three levels of potassium fertilizer. The differences were most significant under treatment without the potassium fertilizer. IR64-K also showed a slightly higher grain yield than IR64 when grown in a paddy field without applying the potassium fertilizer. These results suggest that enhanced sodium uptake ability improves the grain yield of rice plants under low-potassium-input conditions

MYB-mediated regulation of lignin biosynthesis in grasses

Recent analyses of cell wall components of various grass mutant and transgenic lines have provided information on characteristic transcriptional regulation of cell wall formation in grasses, although its knowledge yet remains limited compared with that for eudicot cell wall formation. MYB transcription factors, which are regarded as downstream regulators operating under NAM, ATAF1/2, and CUC2 (NAC) domain transcription factors, have been suggested to be involved in direct regulation of cell wall biosynthesis. In this review, we discuss MYB-mediated transcriptional regulation of the biosynthesis of grass lignins, including grass-specific lignin components such as γ-acyl groups and flavone tricin units. Grass mutant and transgenic lines harboring modified cell-wall-associated MYB genes display altered composition of the γ-acylated and tricin-incorporated lignin units and/or modified expression of enzyme genes involved in the formation of these grass-specific lignin components along with conserved monolignol biosynthetic genes. These findings implicate important roles for MYB transcription factors in coordinated regulation of grass lignin biosynthesis including γ-acylated and tricin-incorporated lignin biosynthesis

Study on Dynamic Characteristics of a Pile Group Foundation

The earthquake response of a structure on group of piles is investigated. The test model, which is employed in this study, is a foundation on four piles. Three conditions are prepared for examination of the contact effects of the foundation bottom and the backfilling effects on dynamic characteristics of the foundation on the piles. Forced vibration tests are carried out for ascertaining the impedance functions as the inertial interaction, and earthquake observations for the earthquake input motion as the kinematic interaction. On the basis of the test and the observation results, the correlation analyses are executed for examining the applicability of the analytical method based on the substructure method in which the three-dimensional wave propagation theory is applied for calculation of the Green\u27s functions. The analytical method is concluded to have sufficient applicability for the practical design procedure of a structure on pile group

Structural basis of lignocellulose deconstruction by the wood-feeding anobiid beetle Nicobium hirtum

The details of the lignocellulose deconstruction processes in the digestive systems of wood-feeding insects remain elusive. This study aimed to examine the biochemical conversion of lignocellulose in the digestive system of a wood-feeding anobiid beetle, Nicobium hirtum, one of the most important pests of wooden products in Japan. To this end, N. hirtum larvae were fed with Japanese red pine (softwood) and Japanese beech (hardwood) sapwood diets, as well as an artificial diet containing Shorea wood (hardwood) sapwood sawdust. The structural differences between the original and digested (feces) lignocellulose samples were examined using wet-chemical and two-dimensional (2D) nuclear magnetic resonance (NMR) methods. Cellulose and hemicelluloses, especially mannan in the softwood diet, were preferentially degraded over lignin in the larval digestive system. As a result, lignin was enriched in the digested lignocellulose residues. Lignin compositional analyses based on thioacidolysis and 2D NMR determined that the proportions of oxidized lignin aromatic units were notably increased after digestion. Further, the 2D NMR analyses revealed the accumulation of aldehyde and hydroxypropiovanillone/syringone end-unit structures in lignin, indicating that oxidative and/or reductive modifications of lignin polymers occur in the larval digestive system. Such structural alterations of lignin may facilitate the dissociation of the lignin barrier, thereby liberating polysaccharides for subsequent enzymatic conversion for assimilation and energy

Altered lignocellulose chemical structure and molecular assembly in CINNAMYL ALCOHOL DEHYDROGENASE-deficient rice

Lignin is a complex phenylpropanoid polymer deposited in plant cell walls. Lignin has long been recognized as an important limiting factor for the polysaccharide-oriented biomass utilizations. To mitigate lignin-associated biomass recalcitrance, numerous mutants and transgenic plants that produce lignocellulose with reduced lignin contents and/or lignins with altered chemical structures have been produced and characterised. However, it is not fully understood how altered lignin chemistry affects the supramolecular structure of lignocellulose, and consequently, its utilization properties. Herein, we conducted comprehensive chemical and supramolecular structural analyses of lignocellulose produced by a rice cad2 mutant deficient in CINNAMYL ALCOHOL DEHYDROGENASE (CAD), which encodes a key enzyme in lignin biosynthesis. By using a solution-state two-dimensional NMR approach and complementary chemical methods, we elucidated the structural details of the altered lignins enriched with unusual hydroxycinnamaldehyde-derived substructures produced by the cad2 mutant. In parallel, polysaccharide assembly and the molecular mobility of lignocellulose were investigated by solid-state 13C MAS NMR, nuclear magnetic relaxation, X-ray diffraction, and Simon’s staining analyses. Possible links between CAD-associated lignin modifications (in terms of total content and chemical structures) and changes to the lignocellulose supramolecular structure are discussed in the context of the improved biomass saccharification efficiency of the cad2 rice mutant

Nav1.1 haploinsufficiency in excitatory neurons ameliorates seizure-associated sudden death in a mouse model of Dravet syndrome

Dravet syndrome is a severe epileptic encephalopathy mainly caused by heterozygous mutations in the SCN1A gene encoding a voltage-gated sodium channel Nav1.1. We previously reported dense localization of Nav1.1 in parvalbumin (PV)-positive inhibitory interneurons in mice and abnormal firing of those neurons in Nav1.1-deficient mice. In the present study, we investigated the physiologic consequence of selective Nav1.1 deletion in mouse global inhibitory neurons, forebrain excitatory neurons or PV cells, using vesicular GABA transporter (VGAT)-Cre, empty spiracles homolog 1 (Emx1)-Cre or PV-Cre recombinase drivers. We show that selective Nav1.1 deletion using VGAT-Cre causes epileptic seizures and premature death that are unexpectedly more severe than those observed in constitutive Nav1.1-deficient mice. Nav1.1 deletion using Emx1-Cre does not cause any noticeable abnormalities in mice; however, the severe lethality observed with VGAT-Cre-driven Nav1.1 deletion is rescued by additional Nav1.1 deletion using Emx1-Cre. In addition to predominant expression in PV interneurons, we detected Nav1.1 in subpopulations of excitatory neurons, including entorhino-hippocampal projection neurons, a subpopulation of neocortical layer V excitatory neurons, and thalamo-cortical projection neurons. We further show that even minimal selective Nav1.1 deletion, using PV-Cre, is sufficient to cause spontaneous epileptic seizures and ataxia in mice. Overall, our results indicate that functional impairment of PV inhibitory neurons with Nav1.1 haploinsufficiency contributes to the epileptic pathology of Dravet syndrome, and show for the first time that Nav1.1 haploinsufficiency in excitatory neurons has an ameliorating effect on the pathology

A Molecular Variant of the Angiotensinogen Gene and Hypertension in a Case-Control Study in Japanese

In order to examine the distribution of M235T (the substitution of threonine for 0methionine at position 235 codon) polymorphism genotypes of the angiotensinogen (AGT) gene and the relationship between M235T polymorphism of the AGT gene and hypertension, a descriptive study and a case-control study were performed among Japanese workers. The subjects were 2042 workers at an occupational site in Shimane Prefecture in Japan. The database was set up for the workers' regular health examination in 1998. The M235T polymorphism of the AGT gene for each worker was defined by the mutant allele specific amplification (MASA) method. The rates of M235M (MM), M235T (MT) and T235T (TT) genotypes were 3.9%, 30.7% and 65.5%, respectively. The odds ratios of MT and TT against MM for hypertension by univariate analysis were 0.77 [95% confidence interval (CI) 0.27-2.18] and 0.77 (95% CI 0.28-2.14), respectively. The odds ratios of MT and TT against MM for hypertension, adjusted for body mass index, fasting blood sugar, drinking habits, cigarette smoking and exercise in a logistic regression model, were 0.90 (95% CI 0.29-2.74) and 0.87 (95% CI 0.30-2.58), respectively. The data from this study suggests that there may be no relationship between the M235T polymorphism of the AGT gene and hypertension. Further prospective studies are needed to resolve this issue