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91.
The effect of alkali extraction on the lignin monomeric composition was examined inEucalyptus camaldulensis andE. globulus by thioacidolysis using extractive-free samples as a control. Results showed that the effect onEucalyptus is different among species and among sample positions in the trunk, although a small amount of lignin is solubilized during the extraction in all samples. In addition, it was proved that lignin extracted by the alkali extraction is not always guaiacyl-rich, probably relating to the original lignin monomeric composition, which depends on the sample species or the sample position in the trunk. 相似文献
92.
Umebayashi T Utsumi Y Koga S Inoue S Shiiba Y Arakawa K Matsumura J Oda K 《Tree physiology》2007,27(7):993-999
To elucidate the water-conducting pathways in living trees by the dye injection method, suitable sample preparation procedures are needed. We evaluated quantitatively the properties and concentrations of three dyes (acid fuchsin, basic fuchsin and safranin) widely used for this purpose, and determined the optimal conditions required to avoid artifacts after dye injection into the sap stream of Pieris japonica D. Don. Among the dyes tested, an aqueous solution of acid fuchsin at a concentration of 0.1% or more was the most useful for delineating water movement. In non-transpiring stem segments, the vertical movement of acid fuchsin by capillarity and diffusion from the dye injection site was limited. However, acid fuchsin moved rapidly in the horizontal direction by capillarity and diffusion, and most xylem cells were stained within 2 h. A delay of more than 2 h between dye injection and examination of the tissues greatly reduces the precision of the method. Use of the dye injection method without appropriate, well-defined experimental procedures may give rise to misleading information about the functional water-conducting pathway in living trees. 相似文献
93.
Hitomi MATSUNARI Toshihiro KOBAYASHI Masahito WATANABE Kazuhiro UMEYAMA Kazuaki NAKANO Takahiro KANAI Taisuke MATSUDA Masaki NAGAYA Manami HARA Hiromitsu NAKAUCHI Hiroshi NAGASHIMA 《The Journal of reproduction and development》2014,60(3):230-237
The development and regeneration of the pancreas is of considerable interest because of the role of these processes in
pancreatic diseases, such as diabetes. Here, we sought to develop a large animal model in which the pancreatic cell lineage
could be tracked. The pancreatic and duodenal homeobox-1 (Pdx1) gene promoter was conjugated to Venus, a
green fluorescent protein, and introduced into 370 in vitro-matured porcine oocytes by intracytoplasmic
sperm injection-mediated gene transfer. These oocytes were transferred into four recipient gilts, all of which became
pregnant. Three gilts were sacrificed at 47–65 days of gestation, and the fourth was allowed to farrow. Seven of 16 fetuses
obtained were transgenic (Tg) and exhibited pancreas-specific green fluorescence. The fourth recipient gilt produced a litter
of six piglets, two of which were Tg. The founder Tg offspring matured normally and produced healthy first-generation (G1)
progeny. A postweaning autopsy of four 27-day-old G1 Tg piglets confirmed the pancreas-specific Venus expression.
Immunostaining of the pancreatic tissue indicated the transgene was expressed in β-cells. Pancreatic islets from Tg pigs were
transplanted under the renal capsules of NOD/SCID mice and expressed fluorescence up to one month after transplantation. Tg
G1 pigs developed normally and had blood glucose levels within the normal range. Insulin levels before and after sexual
maturity were within normal ranges, as were other blood biochemistry parameters, indicating that pancreatic function was
normal. We conclude that Pdx1-Venus Tg pigs represent a large animal model suitable for research on
pancreatic development/regeneration and diabetes. 相似文献
94.
Motoki SASAKI Yoko AMANO Daisuke HAYAKAWA Toshio TSUBOTA Hajime ISHIKAWA Toshihiro MOGOE Seiji OHSUMI Masafumi TETSUKA Akio MIYAMOTO Yutaka FUKUI Teguh BUDIPITOJO Nobuo KITAMURA 《The Journal of reproduction and development》2014,60(1):62-67
In this study, we examined the existence and structure of areolae and the
steroidogenesis of areolar trophoblast cells in the Antarctic minke whale placenta
morphologically and immunohistochemically. Placentas were collected from the 15th, 16th
and 18th Japanese Whale Research Program under Special Permit in the Antarctic (JARPA) and
1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. The opening
and cavity of fetal areolae formed by taller columnar trophoblast cells (areolar
trophoblast cells) with long microvilli and a bright cytoplasm, as compared with the
trophoblast cells of the chorionic villi interdigitating with the endometrial crypts, were
recognized in observations of serial sections. The opening of the areolar cavity was
hidden by chorionic villi with areolar trophoblast cells. Furthermore, a closed pouch-like
structure lined by tall columnar cells similar to areolar trophoblast cells within the
stroma of chorionic villi was noticed and continued to the areolar cavity, with the
opening seen on serial sections. In a surface investigation of the chorion and endometrium
by SEM, maternal (endometrial) areolae irregularly surrounded by endometrial folds were
obvious. Moreover, we distinguished areolar trophoblast cells with long microvilli
attached with many blebs from trophoblast cells. In our immunohistochemical observations,
a steroidogenic enzyme, cytochrome P450 side chain cleavage enzyme (P450scc), was detected
with strong immunoreactivity in trophoblast cells. However, areolar trophoblast cells
showed weak or no immunoreactivity for P450scc. 相似文献
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Nakamura T Noguchi T Tanaka M Zolensky ME Kimura M Tsuchiyama A Nakato A Ogami T Ishida H Uesugi M Yada T Shirai K Fujimura A Okazaki R Sandford SA Ishibashi Y Abe M Okada T Ueno M Mukai T Yoshikawa M Kawaguchi J 《Science (New York, N.Y.)》2011,333(6046):1113-1116
The Hayabusa spacecraft successfully recovered dust particles from the surface of near-Earth asteroid 25143 Itokawa. Synchrotron-radiation x-ray diffraction and transmission and scanning electron microscope analyses indicate that the mineralogy and mineral chemistry of the Itokawa dust particles are identical to those of thermally metamorphosed LL chondrites, consistent with spectroscopic observations made from Earth and by the Hayabusa spacecraft. Our results directly demonstrate that ordinary chondrites, the most abundant meteorites found on Earth, come from S-type asteroids. Mineral chemistry indicates that the majority of regolith surface particles suffered long-term thermal annealing and subsequent impact shock, suggesting that Itokawa is an asteroid made of reassembled pieces of the interior portions of a once larger asteroid. 相似文献