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941.
Embryonic development of the liver is closely associated with vascular organization. However, little is known about the mechanisms of vascular differentiation during liver development. Our previous study showed that the maturation of sinusoidal endothelial cells (SECs) occurred during embryonic day 13.0 (E13.0) to E15.0. To improve our understanding of SEC differentiation, we examined here the expression of maturation markers, SE-1 and stabilin-2, in fetal livers and also attempted to establish an in vitro SEC differentiation system by culturing E13.5 fetal liver cells. Immunohistochemical examination of SE-1 and stabilin-2 expression during fetal rat liver development revealed that these differentiation markers were co-expressed in SECs in the late stage of liver development, although stabilin-2 was expressed in almost all vascular endothelial cells in the early stage. Liver cells from the E13.5 rat fetus were cultured in EBM-2 medium containing vascular endothelial growth factor (VEGF), transforming growth factor β1 (TGF-β1) and VEGF plus SB-431542 (an inhibitor of the TGF-β1 receptor, activin receptor-like kinase 5 [ALK-5]). In vitro SEC differentiation, as indicated by the appearance of cells co-expressing SE-1 and stabilin-2 and of cells with cytoplasmic fenestrae in endothelial sheets, was induced by the addition of both VEGF and SB-431542, an inhibitor of the phosphorylation of Smad2/3 but not that of Smad1/5/8 in the cultured cells. These results indicate for the first time that both VEGF signaling and the blocking of the ALK-5-Smad2/3 signal pathway are important for the fetal differentiation of SECs.  相似文献   
942.
External and internal flavonoids were isolated from 12 Uncarina taxa (Pedaliaceae), endemic to Madagascar. Four flavone aglycones, tricetin 7,3′,5′-trimethyl ether, tricetin 7,4′,5′-trimethyl ether, 5,3′-dihydroxy-6,7,4′,5′-tetramethoxyflavone and eupatorin were isolated from leaf wax of seven Uncarina taxa, Uncarina grandidieri, Uncarina decaryi, Uncarina abbreviata, Uncarina turicana, Uncarina platycarpa, Uncarina leandrii var. leandrii and Uncarina peltata, but not Uncarina stellulifera, Uncarina perrieri, Uncarina sakalava, Uncarina leptocarpa and U. leandrii var. rechbergeri. Furthermore, eight flavonoid glycosides were isolated from the leaves. Major glycosides were apigenin and luteolin 7-O-glucuronides and occurred in all the Uncarina taxa examined, except the absence of the former compound in U. peltata. Other glycosides were identified as hispidulin, jaceosidin, chrysoeriol and tricin 7-O-glucuronides, and luteolin 7,4′-di-O-glucuronide and a flavonol, isorhamnetin 3-O-diglucoside. From the results described above, methylated flavone aglycones and glucuronides were chemical characters of the leaves of Uncarina species, and also may be those of the family Pedaliaceae. Besides, an anthocyanin, two flavonols and three flavones were isolated from the flowers of U. grandidieri, and identified as cyanidin 3-O-rutinoside (anthocyanin), quercetin and isorhamnetin 7-O-glucuronides (flavonols) and apigenin, luteolin and jaceosidin 7-O-glucuronides (flavones).  相似文献   
943.
944.
Rhodococcus erythropolis N9T-4, which was isolated from crude oil, showed extremely oligotrophic growth and formed its colonies on a minimal salt medium solidified using agar or silica gel without any additional carbon source. N9T-4 did not grow under CO(2)-limiting conditions but could grow on a medium containing NaHCO(3) under the same conditions, suggesting that the oligotrophic growth of N9T-4 depends on CO(2). Proteomic analysis of N9T-4 revealed that two proteins, with molecular masses of 45 and 55 kDa, were highly induced under the oligotrophic conditions. The primary structures of these proteins exhibited striking similarities to those of methanol: N,N'-dimethyl-4-nitrosoaniline oxidoreductase and an aldehyde dehydrogenase from Rhodococcus sp. These enzyme activities were three times higher under oligotrophic conditions than under n-tetradecane-containing heterotrophic conditions, and gene disruption for the aldehyde dehydrogenase caused a lack of growth on the minimal salt medium. Furthermore, 3-hexulose 6-phosphate synthase and phospho-3-hexuloisomerase activities, which are key enzymes in the ribulose monophosphate pathway in methylotrophic bacteria, were detected specifically in the cell extract of oligotrophically grown N9T-4. These results suggest that CO(2) fixation involves methanol (formaldehyde) metabolism in the oligotrophic growth of R. erythropolis N9T-4.  相似文献   
945.
The overall structure of type IV collagen is the same at neutral and acidic pH, as determined by circular dichroism spectra. The heating rate dependence of denaturation midpoint temperature (T(m)) shows that type IV collagen is unstable at body temperature, similarly to type I collagen. The heating rate dependence of T(m) at neutral pH has two phases, but that at acidic pH apparently has a single phase. The T(m) of the first phase (lower T(m)) at neutral pH is consistent with that at acidic pH, and the activation energy of these phases is consistent, within experimental error. The triple helix region of type IV collagen corresponding to the second phase (higher T(m)) at neutral pH is thermally stable when compared to the triple helical structure at acidic pH. At acidic pH, as the loosely packed and unstable region has spread throughout the whole molecule, the thermal transition is thought to be cooperative and is observed as a single phase. Structural flexibility is related to protein function and assembly; therefore, the unstable structure and increased flexibility of type IV collagen induced at acidic pH may affect diseases accompanied by type IV collagen disorder.  相似文献   
946.
Here we provided the first genetic evidence for an association between the degree of apocrine colostrum secretion and human earwax type. Genotyping at the earwax-type locus, rs17822931 within the ABCC11 gene, revealed that 155 of 225 Japanese women were dry-type and 70 wet-type. Frequency of women without colostrum among dry-type women was significantly higher than that among wet-type women (P < 0.0002), and the measurable colostrum volume in dry-type women was significantly smaller than in wet-type women (P = 0.0341).  相似文献   
947.
We designed and synthesized hydroxamic acid derivatives bearing a 4-(3-pyridyl)phenyl group as a cap structure, and found that they exhibit potent histone deacetylase (HDAC) inhibitory activity. A representative compound, 17a, showed more potent growth-inhibitory activity against pancreatic cancer cells and greater upregulation of p21(WAF1/CIP1) expression than the clinically used HDAC inhibitor suberoylanilide hydroxamic acid (Zolinza).  相似文献   
948.
He K  Gou X  Yuan T  Lin H  Asami T  Yoshida S  Russell SD  Li J 《Current biology : CB》2007,17(13):1109-1115
Brassinosteroids (BRs) are phytosteroid hormones controlling various physiological processes critical for normal growth and development. BRs are perceived by a protein complex containing two transmembrane receptor kinases, BRASSINOSTEROID INSENSITIVE 1 (BRI1) and BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1) [1-3]. BRI1 null mutants exhibit a dwarfed stature with epinastic leaves, delayed senescence, reduced male fertility, and altered light responses. BAK1 null mutants, however, only show a subtle phenotype, suggesting that functionally redundant proteins might be present in the Arabidopsis genome. Here we report that BAK1-LIKE 1 (BKK1) functions redundantly with BAK1 in regulating BR signaling. Surprisingly, rather than the expected bri1-like phenotype, bak1 bkk1 double mutants exhibit a seedling-lethality phenotype due to constitutive defense-gene expression, callose deposition, reactive oxygen species (ROS) accumulation, and spontaneous cell death even under sterile growing conditions. Our detailed analyses demonstrate that BAK1 and BKK1 have dual physiological roles: positively regulating a BR-dependent plant growth pathway, and negatively regulating a BR-independent cell-death pathway. Both BR signaling and developmentally controlled cell death are critical to optimal plant growth and development, but the mechanisms regulating early events in these pathways are poorly understood. This study provides novel insights into the initiation and crosstalk of the two signaling cascades.  相似文献   
949.
This paper describes the process of encapsulating hair growing ingredients in the PLGA nanospheres by emulsion solvent diffusion method and investigates the feasibility of using the PLGA nanospheres as the DDS (Drug delivery System) carriers for delivering various hair growing ingredients to hair follicles. In-vitro and in-vivo tests were conducted to verify the performances of encapsulated PLGA nanospheres with three different hair growing ingredients. In the in-vitro tests, the scalp-pore permeability of hair growing ingredient encapsulated PLGA nanospheres (dispersed in the PBS solution) was examined using human scalp biopsies in a modified Bronaugh diffusion chamber in comparison to that of the control samples containing the hair growing ingredient in the PBS solution. Furthermore, the hair growing effect of the encapsulated PLGA nanospheres was evaluated with the C3H mice in the in-vivo tests. By observing the fluorescence intensity of the ingredients, as shown in the cross-section photographs of the human scalp biopsies, it was found that the dispersion liquids containing hair growing ingredient encapsulated PLGA nanospheres exerted a scalp-pore permeability 2.0- to 2.5-fold more marked than that of the control samples. Also, the hair growing activities were enhanced by using the encapsulated PLGA nanospheres, which transformed the hair growth cycle from the resting phase to the growing phase. As a result, the degree of hair growth was improved significantly. These results suggested that the PLGA nanosphere can be a new DDS carrier for delivering hair growing ingredients and drugs to the hair follicles.  相似文献   
950.
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