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261.
Fukuoka K Sawabe A Sugimoto T Koga M Okuda H Kitayama T Shirai M Komai K Komemushi S Matsuda K 《Journal of agricultural and food chemistry》2004,52(20):6326-6329
Atherosclerosis is a vascular disorder involving inflammation, a narrowed vascular lumen in the entire tunica intima, and reduced elasticity of the arterial wall. It has been found that Hsp60 from Chlamydia pneumoniae, an obligate bacterial pathogen associated with atheroma lesions, mimics human Hsp60, thereby causing attacks by immune cells on stressed endothelial cells expressing endogenous Hsp60 on their surface. Furthermore, Hsp60 from C. pneumoniae has been shown to promote the growth of vascular smooth muscle cells (VSMCs). To explore probes that can be used for studying signal transduction elicited by the chlamydial Hsp60, we have tested several natural products for their inhibitory actions on the Hsp60-induced proliferation of rat arterial smooth muscle cells. Sesamol, vanillyl alcohol, and trans-ferulic acid exhibited moderate inhibitory actions on the Hsp60-induced cell proliferation; zerumbone, humulene, and caryophylene effectively inhibited it at low concentrations with IC(50) values of 529, 122, and 110 nM, respectively. The results indicated that the 11-membered alicyclic ring is favorable for interactions with receptors involved in the Hsp60-induced VSMC proliferation. 相似文献
262.
Ikeda I Kobayashi M Hamada T Tsuda K Goto H Imaizumi K Nozawa A Sugimoto A Kakuda T 《Journal of agricultural and food chemistry》2003,51(25):7303-7307
It has been known that tea catechins, (-)-epicatechin (1), (-)-epigallocatechin (2), (-)-epicatechin gallate (3), and (-)-epigallocatechin gallate (4) are epimerized to(-)-catechin (5), (-)-gallocatechin (6), (-)-catechin gallate (7), and (-)-gallocatechin gallate (8), respectively, during retort pasteurization. We previously reported that tea catechins, mainly composed of 3 and 4, effectively inhibit cholesterol absorption in rats. In this study, the effect of heat-epimerized catechins on cholesterol absorption was compared with tea catechins. Both tea catechins and heat-epimerized catechins lowered lymphatic recovery of cholesterol in rats cannulated in the thoracic duct and epimerized catechins were more effective than tea catechins. The effect of purified catechins on micellar solubility of cholesterol was examined in an in vitro study. The addition of gallate esters of catechins reduced micellar solubility of cholesterol by precipitating cholesterol from bile salt micelles. Compounds 7 and 8 were more effective to precipitate cholesterol than 3 and 4, respectively. These observations strongly suggest that heat-epimerized catechins may be more hypocholesterolemic than tea catechins. 相似文献
263.
The diversity of host invasion mechanisms of the causal pathogen of Japanese cedar twig blight (Stromatinia cryptomeriae) was elucidated through detailed investigations of the disease cycle. Scanning electron microscopy (SEM) showed that ascospores
began to germinate, and invade male strobilus tissue, within 24 h after arriving on the strobili. This involved direct penetration
of the cuticle, and examination by SEM showed that cuticle degeneration had occurred around the point of penetration. A mucilage-like-substance
was also observed around the tips of the germ tubes. Meanwhile field studies showed that incipient mycelial mat emerged from
the bases of male strobilus in early June, and ceased growing onto the surface of the twig at the beginning of July. Macroscopically,
the mycelial mat began to shed in mid-July, and disappeared completely during the summer season by the end of August. Immediately
after the mat disappeared the first necrotic symptoms became evident on the twigs. This suggested strongly that these mats
were involved in lesion formation. Observations of the mat’s behavior on the surface of twigs with light and differential
interference microscopy, and SEM, showed thatS. cryptomeriae had two modes of invasion,i.e. stomatal and cuticular invasion. Hyphae from the mat were able to enter twig tissues through the stomata. Additionally, mycelial
mat infected host tissue directly by hyphal penetration of the cuticle at the axes of cedar twigs. The mat was able to grow
along the twig surface, then hyphae forming mat entered the host tissue and caused necrotic lesions. This paper describes
the mechanisms of infection on both a strobilus and twig utilized by the pathogen of Japanese cedar twig blight. 相似文献
264.
Takuya Akiyama Tomoko Sugimoto Yuji Matsumoto Gyosuke Meshitsuka 《Journal of Wood Science》2002,48(3):210-215
Ozonation as a quantitative tool to analyze the stereo structures of arylglycerol--aryl ether linkages was examined using wood meal, milled wood lignin, and a lignin model compound, 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol (veratrylglycerol--guaiacyl ether, VG). The procedure was improved. When mild postreduction was conducted for ozonation products, the total yield of erythronic and threonic acids from this model compound was 74%, which is 15% higher than the yield without postreduction. A decrease in the recovery of these two acids under prolonged ozonation treatment was successfully suppressed by postreduction. Theerythro/threo ratio of VG determined by the ozonation method with postreduction is in good agreement with the ratio determined by1H-nuclear magnetic resonance. Excellent reproducibility of the yield was obtained by adopting a procedure that included trimethylsilylation of ammonium salts of ozonation products using a dimethylsulfoxide-hexamethyldisilazane-trimethylchlorosilane mixture and subjecting it to gas chromatography analysis. It was concluded that arylglycerol--aryl ether structures comprise at least 35% of the C3-C6 structure in birch wood meal, with anerythro/threo ratio of 2.8.This paper was presented at the 43rd Lignin Symposium, Fuchu, Japan, October 1998; and at the 10th ISWPC, Yokohama, Japan, June 1999 相似文献
265.
We investigated the relationship between turgor pressure and diurnal differences in secondary wall formation of differentiating
tracheids. Saplings of Cryptomeria japonica were grown in a growth chamber with 12-h light:12-h dark cycles, and the tangential strain on the inner bark surface was
measured as an indicator of the volumetric changes of differentiating cells. The innermost surface of developing secondary
walls was then observed using field emission scanning electron microscopy at 1-h intervals after both light and dark periods.
Dramatic changes in the aspects of the innermost surface of developing secondary walls occurred 3h after the light was switched
on and 4h after the light was switched off. The amorphous material containing glucomannans became evident when the differentiating
cells became fully turgid during the dark period. Conversely, cellulose microfibrils became clearly visible when the cell
volume was low during the light period. These results suggest that the diurnal periodicity in the supply of hemicellulose-containing
matrix to developing secondary walls is associated with the changes in turgor pressure of differentiating tracheids that result
from the change in light conditions during the photoperiodic cycle. 相似文献
266.
We conducted creep tests to evaluate creep behaviors of conventional Japanese framing (jikugumi) structures as reported in a previous article. We measured beam deflections of two structures: one of them was composed of
only green timbers (G) and the other with only kiln-dried timbers (D). Besides the two structures, we prepared green and kiln-dried
beams to measure moisture content (MC), weight, and dynamic Young’s modulus (E
f) by the longitudinal vibration method. We attempted to predict deflections of beams in the structures by using experimental
data for single beam specimens. The proposed simple predictive model was derived from two equations: a relation between MC
and equilibrium moisture content calculated with temperature and relative humidity, and a relation between MC change and relative
deflection change. Beam deflections were traced for 2.5 years, while the predictions were based on experimental data from
loading to the 11th day of the test. It was assumed that sensitivity of deflection change to MC should differ during desorption
or adsorption. Although annual cyclic changes were observed in E
f, there was no obvious relationship between E
f and beam deflection.
Part of this article was presented at the Annual Meeting of the Architectural Institute of Japan, Kyushu, September 1998 相似文献
267.
Seiichi Yasuda Eri Hamaguchi Yasuyuki Matsushita Hideyuki Goto Takanori Imai 《Journal of Wood Science》1998,44(2):116-124
Highly condensed lignin can be transformed by three reactions — phenolation, hydroxymethylation, and neutral sulfonation — to water-soluble lignosulfonate. To elucidate reactivities and products in the latter two reactions, simple compounds were selected as lignin model compounds. With hydroxymethylation of creosol at 60°C, the yield of a condensed-type product with the diarylmethane structure was less than 10%. Hydroxymethylation of 1-guaiacyl-1-p-hydroxy-phenylethane (compound VI) as a phenolized guaiacyl lignin model compound gave four compounds. The initial reaction introduced the hydroxymethyl group mainly in the guaiacyl nucleus, and the additional reaction created two hydroxymethyl groups in the p-hydroxyphenyl nucleus. Contrary to our estimation, treatment of the models with 13C-labeled formaldehyde (H13CIIO) did not form any diarylmethane structure. Neutral sulfite treatment of hydroxymethylated products gave corresponding sulfonates in high yields. Phenolized guaiacylglycerol--aryl ether (compound XVI) showed a reactivity similar to that of compound VI.This paper was presented at the 45th and 46th annual meetings of the Japan Wood Research Society at Tokyo and Kumamoto, April 1995 and April 1996, respectively 相似文献
268.
Delignified hinoki wood and cellulose as well as hinoki and lauan woods were carbonized at 590°C for 1 h. The dielectric properties
of these specimens were measured at 20°C in a frequency range of 20 Hz to 1 MHz. Inflection points in the dielectric constant
(ε′) versus the logarithm of frequency (log f) curves as well as in the logarithm of the electric conductivity (log σ) versus log f curves for all specimens prepared were recognized. Peaks in the dielectric loss and the imaginary part of the complex conductivity
versus the log f curves were detected in the frequency location corresponding to the inflection point in the ε′ and log σ versus log f curves. It was considered that this relaxation was responsible for the interfacial polarization observed in heterogeneous
materials because no permanent dipoles existed in the specimens carbonized above 500°C. The Cole–Cole circular arc law was
applied to account for this relaxation. Similar average relaxation times were obtained for all specimens. These results suggested
that the observed relaxation was ascribed to interfacial polarization at microscopic levels in the cell walls. 相似文献
269.
Yasuyuki Matsushita Hitomi Sano Masanori Imai Takanori Imai Kazuhiko Fukushima 《Journal of Wood Science》2007,53(1):67-70
To study the behavior of hardwood sulfuric acid lignin (SAL) during phenolization, we compared the product yield, average
molecular weight, methoxy content, and reactions of simple model compounds with those of softwood SAL, focusing on the difference
between syringyl and guaiacyl units. The beech SAL reacted with phenol more readily than red pine SAL and yielded a larger
soluble fraction of phenolized SAL. To investigate the difference in the phenolization activity of the syringyl and guaiacyl
units in beech lignin, we prepared syringyl-nucleus-rich sulfuric acid lignin (S-rich-SAL) and guaiacyl-nucleus-rich sulfuric
acid lignin (G-rich-SAL) from beech, which were subjected to phenolization. The results suggest that the syringyl unit in
SAL had greater phenolization activity and its phenolized products were more soluble in acidic aqueous medium and introduced
less phenol than the guaiacyl unit. Using model compounds, the study also showed that the syringyl unit had higher phenolization
reactivity than the guaiacyl unit. 相似文献
270.
Wen Zhong Zhuang Chihiro Sugimoto Shuichi Kubota Sadao Onoe Misao Onuma 《Veterinary parasitology》1995,60(3-4):191-198
Theileria sergenti piroplasms were purified from different parasitemia peaks of cattle infected with parasitized erythrocytes or sporozoites during persistent infection. Their activities with monoclonal antibodies 13F5 and C9, which recognize 23 kDa and 32 kDa piroplasm surface proteins, respectively, were analyzed. Antigenic differences were observed among parasites from different parasitemia peaks during persistent infection when cattle were infected with sporozoites. Results of two-dimensional polyacrylamide gel electrophoresis showed that the 23 and 32 kDa proteins were expressed in all samples tested, regardless of their reactivities with the monoclonal antobodies. In contrast, parasites obtained from cattle inoculated with parasitized erythrocytes showed no antigenic alteration over a 2 month observation period. The results suggest that antigenic alteration of T. sergenti during persistent infection is related to whether the parasites proliferate through extraerythorocytic schizont stage in cattle or sporozoite and other sexual stages in tick vector. 相似文献