Generation and alteration of norlignans in a transition zone during the drying of a Cryptomeria japonica log     

Kazumasa Yoshida  Mitsuru Nishiguchi  Shojiro Hishiyama  Atsushi Kato  Koetsu Takahashi 《Journal of Wood Science》2006,52(4):372-375

Sugi (Cryptomeria japonica D. Don) produces secondary metabolite norlignans in xylem. Several norlignans are involved in the coloration of heartwood and defense of sapwood against microbial invasion. Their biosynthetic process should be well understood so that their properties can be exploited to improve the quality and utility of C. japonica wood. Unfortunately, information on the norlignan biosynthesis is limited because norlignans are mainly synthesized in a particular season in the transition zone (TZ) along with the heartwood formation, and is difficult to study. Although the generation of two norlignans of C. japonica, agatharesinol and (E)-hinokiresinol, has been reported, systems for producing other norlignans are not yet known. To establish a novel norlignan generating system, we examined the changes occurring in norlignans in a TZ during the process of drying a C. japonica log. On the day of felling, the TZ contained agatharesinol and (E)-hinokiresinol, which increased until they reached a maximum on day 40 after felling. Sequirin-C appeared on day 40 and increased to day 70. The generation of sequirin-C in the TZ can be used to investigate the biosynthetic process of heartwood norlignans. This study describes for the first time the changes that occur in the composition of norlignan during the drying of the TZ.  相似文献   

Preparation and Characterization of Phenolated Wood Using Sulfuric Acid as a Catalyst I: Liquefaction Behavior of Plantation Wood     

Atsushi IKEDA 《中国林业科技(英文版)》2002,(4)

Chinese fir (Cunninghamia lanceolata) and poplar (Populus spp.) wood meal were phenolated in the presence of sulfuric acid used as a catalyst. The effects of reaction time and reaction temperature on the wood liquefaction were investigated. The results showed that the reaction temperature had the greater influence on the residue content than reaction time. Additionally, the liquefaction curve for the Chinese fir and Poplar were similar in general.  相似文献   

Stem water transport of Lithocarpus edulis, an evergreen oak with radial-porous wood     

Hirose S  Kume A  Takeuchi S  Utsumi Y  Otsuki K  Ogawa S 《Tree physiology》2005,25(2):221-228

The stem water conducting system of an evergreen broad-leaved oak, Lithocarpus edulis (Mak.) Nakai, was investigated. Evergreen broad-leaved oaks (Lithocarpus, Castanopsis, Cyclobalanopsis, Quercus) belonging to the Quercoideae are a major component of Asian monsoon forests, and are characterized by the possession of radial-porous wood. A characteristic of radial-porous wood is the development of aggregate rays between radially oriented files of vessels. We measured the distribution of vessel lumen diameters in a stem cross section and calculated the theoretical water conductivity of the wood. The radial profile of the heat pulse velocity (HPV) was measured for an intact whole tree under field conditions and compared with the theoretical distribution of water conductivity. Soft X-ray photographs of frozen stem sections indicated that most of the vessel lumina were filled with water, including those of vessels more than 20 years old. Even when vessels were relatively wide (lumen diameters > 100 microm), cavitation was negligible. The rate of water uptake from the cut stem base correlated closely with HPV (r = 0.96), and HPV closely reflected the mean volume flow per stem sectional area (SFVS) around the sensor probes. However, the ray tissue sharply inhibited heat transfer, and the positioning of the probes strongly affected the absolute value of HPV. It was also found that HPV more closely reflected the mean sap flow velocity in the vessels than did SFVS.  相似文献   

Hydration behavior and compressive strength of cement mixed with exploded wood fiber strand obtained by the water-vapor explosion process     

Yi Min Wei  Bunichiro Tomita  Yasushi Hiramatsu  Atsushi Miyatake  Tsuyoshi Fujii  Tomoyuki Fujii  Shuichiro Yoshinaga 《Journal of Wood Science》2003,49(4):317-326

Poor compatibility was found between exploded wood fiber strand (WFS) and cement due to the excessive presence of water-soluble degraded polysaccharides in extractives of exploded WFS obtained from weathered wood waste treated by the water-vapor explosion process (WVEP). This study presents some comparative results from a continuing investigation on the compressive strengths of exploded WFS–cement mixtures. Based on results previously obtained with the hydration test, the relation between hydration behavior and compressive strength of the mixture was explored. In addition, the effect of the curing age on compressive strength development of the mixture with selected additive chemicals was examined. The results supported the results of early studies with hydration tests indicating that adding MgCl₂ to the mixtures of exploded WFS mixed with quick-curing cement or ordinary Portland cement and a composite of MgCl₂ + CaO added to the mixture of exploded WFS and furnace-slag cement effectively improved the hydration behaviors; it greatly enhanced the compressive strengths of mixtures as well. Compressive strengths were strongly correlated to maximum hydration temperatures (T_max) of wood–cement mixtures influenced by the cement type, wood wastes (treated or not with WVEP), additive chemicals, and their content levels. The results also indicated that adding selected chemicals had no significant effect on compressive strength among the mixtures of exploded WFS mixed, respectively, with three types of cement at a curing age of 180 days. X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy were used to identify the hydration products and to probe the element distribution of the mixture in the wood–cement interface zone from a fractured surface.Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002  相似文献   

Structure of xylan from culms of bamboo grass (Sasa senanensis Rehd.)     

Shigeki Yoshida  Atsushi Kuno  Naoto Saito  Masakazu Aoyama  Isao Kusakabe 《Journal of Wood Science》1998,44(6):457-462

Xylan prepared from culms of kumaizasa (Sasa senanensis Rehd.), a representative species of bamboo grass, was hydrolyzed with-xylanase ofStreptomyces olivaceoviridis E-86. Four arabinoxylo-oligosaccharides and two glucuronoxylo-oligosaccharides were isolated from the enzymatic hydrolysate of the xylan by chromatography on a charcoal column, a Dowex 1-x8 column, a Toyo-pearl HW-40S column, and a LiChrospher 100 NH₂ column and on preparative paper chromatography. The results of the structural analyses of the saccharides showed that the isolated oligosaccharides had the structures of 3²--l-arabinofuranosyl-xylobiose, 3²--l-arabinofuranosyl-xylotriose, 3²--[-d-xylopyranosyl-(1 2)-l-arabinofuranosyl]-xylobiose, 3³--[-d-xylopyranosyl-(1 2)-l-arabinofuranosyl]-xylotriose, 2³--4-O-methyl-d-glucuronosyl-xylotriose, and 2³--d-glucuronosyl-xylotriose. From the structural analysis of the oligosaccharides derived from the xylan, kumaizasa xylan was concluded to be a kind of arabinoglucuronoxylan having not only stubs of singlel-arabinose and singled-glucuronic acid but also stubs of disaccharide units such as-d-xylopyranosyl-(1 2)-l-arabinofuranose.  相似文献   

Effects of current-year and previous-year PPFDs on shoot gross morphology and leaf properties in Fagus japonica     

Kimura K  Ishida A  Uemura A  Matsumoto Y  Terashima I 《Tree physiology》1998,18(7):459-466

We investigated how shoot gross morphology and leaf properties are determined in Fagus japonica Maxim., a deciduous species with flush-type shoot phenology, in which all leaves are produced in a single flush at the start of each season. We examined relationships between current-year shoot properties and local light environment in a 14-m tall beech tree growing in a deciduous forest. Leaf number (LN), total leaf area (TLA), and total leaf length (SL) of the current-year shoot increased with increasing photosynthetic photon flux density (PPFD). Leaf thickness, dry mass per leaf area and nitrogen content on a leaf area basis increased, whereas the chlorophyll/N ratio decreased with increasing PPFD. To separate the effects of current-year PPFD from those of previous year(s), we artificially shaded a part of the uppermost leaf tier. Reciprocal transfers of beech seedlings between controlled PPFD regimes were also made. Characteristics of shoot gross morphology such as LN, TLA and SL were largely determined by the PPFD of the previous year. The exception was the length of the longest "long shoots" with many leaves, in which elongation appeared to be influenced by both previous-year and current-year PPFD. In contrast, leaf properties were determined by current-year PPFD. The ecological implications of our findings are discussed.  相似文献   

Lipopolysaccharide induces expression of collagen VI in the rat lung     

Sayuri Okawa  Kana Unuma  Atsushi Yamada  Toshihiko Aki  Koichi Uemura 《Journal of toxicologic pathology》2015,28(1):37-41

The involvement of the lung during the septic systemic inflammatory response elicited by administration of lipopolysaccharide (LPS) was investigated. Eight-week-old male Sprague–Dawley rats were injected i.p. with 15 mg/kg LPS. After 24 h, the lungs were excised to evaluate the cellular responses to LPS. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) analysis revealed that type VI collagen (ColVI) was extremely upregulated during sepsis in the rat lung within the first 24 h of LPS administration. Upregulation of ColVI protein and its mRNA was demonstrated by Western blot analysis, real time PCR, and immunohistochemistry. To the best of our knowledge, this is the first report demonstrating the activation of ColVI in the rat lung at the early stage of systemic inflammation. Activation of ColVI might be involved in sepsis-mediated lung fibrosis at an early stage.  相似文献   

Time course of the incidence/multiplicity and histopathological features of murine colonic dysplasia,adenoma and adenocarcinoma induced by benzo[a]pyrene and dextran sulfate sodium     

Jiro Sonoda  Yuki Seki  Atsushi Hakura  Satoru Hosokawa 《Journal of toxicologic pathology》2015,28(2):109-120

Benzo[a]pyrene (BP) is mutagenic but noncarcinogenic in the murine colon. Recently, we reported rapid induction of colonic tumors by treatment of CD2F₁ mice with BP (125 mg/kg for 5 days) followed by a colitis inducer, dextran sulfate sodium (DSS) (4% in drinking water for 1 or 2 weeks). However, there are no reports on detailed time course and histopathological features of colonic proliferative lesions in this model. Here, we show the detailed time course of colonic dysplasia, adenoma and adenocarcinoma induced by treatment with BP, DSS, and a combination of the two (BP/DSS). In the colon of mice exposed to BP/DSS, 14.6 dysplastic foci per mouse were present one week after DSS treatment (week 4). The number of dysplastic foci decreased with time to 3.1 at week 9 and thereafter remained almost constant. At week 4, 1.5 adenocarcinomas were also observed, with a marked increase in numbers with time, reaching 29.3 at week 14. In contrast, the number of dysplastic foci induced by DSS alone showed a time course similar to that following BP/DSS treatment; however, only a few tumors appeared. Neither dysplastic foci nor neoplastic lesions were induced by BP only. In mice exposed to BP/DSS, β-catenin was demonstrated immunohistochemically in the nucleus and/or cytoplasm of the tumor cells, and this translocation from the cell membrane was evident in subsets of dysplastic foci. In dysplastic foci induced by DSS alone, β-catenin was absent in the nucleus/cytoplasm. These finding suggest that aberrant β-catenin accumulation in dysplastic foci is associated with tumor progression in this BP/DSS model.  相似文献   

Anethole inhibits growth of recently emerged multidrug resistant toxigenic Vibrio cholerae O1 El Tor variant strains in vitro     

M. Shamim Hasan ZAHID  Sharda Prasad AWASTHI  Atsushi HINENOYA  Shinji YAMASAKI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(5):535-540

To search natural compounds having inhibitory effect on bacterial growth is important, particularly in view of growing multidrug resistant (MDR) strains of bacterial pathogens. Like other bacterial pathogens, MDR Vibrio cholerae, the causative agent of diarrheal disease cholera, is becoming a great concern. As an approach of searching new antimicrobial agents, here, we show that anethole, a well-studied natural component of sweet fennel and star anise seeds, could potentially inhibit the growth of MDR O1 El Tor biotype, the ongoing 7th cholera pandemic variant strains of toxigenic V. cholerae. The minimum inhibitory concentration (MIC) of anethole against diverse O1 El Tor biotype strains is evaluated as 200 µg/ml. Moreover, the effect of anethole is bactericidal and exerts rapid-killing action on V. cholerae cells. This study is the first report which demonstrates that anethole, purified from natural compound, is a potent inhibitor of growth of toxigenic V. cholerae. Our data suggest that anethole could be a potential antimicrobial drug candidate, particularly against MDR V. cholerae mediated infections.  相似文献   

Plasma fluctuation in estradiol-17β and bone resorption markers around parturition in dairy cows     

Bhuminad DEVKOTA  Masahiro TAKAHASHI  Saori SATO  Kouya SASAKI  Atsushi UEKI  Takeshi OSAWA  Masahiro TAKAHASHI  Norio YAMAGISHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(7):875-878

Blood samples were obtained sequentially from 10 dairy cows around the time of parturition to assess plasma fluctuations in estradiol-17β (E₂) levels in association with those of several bone resorption markers. Plasma E₂ concentration increased sharply a few days prepartum and decreased quickly after parturition. In terms of bone resorption markers, the plasma level of tartrate-resistant acid phosphatase isoform 5b (TRAP5b) rose significantly, commencing 1 week prepartum, and was maintained at this level to a few days postpartum. The plasma concentration of carboxyterminal collagen cross-links of type-I collagen (CTx) increased significantly after parturition. These observations suggest that osteoclast-mediated bone resorption was activated after parturition when plasma E₂ concentrations decreased.  相似文献