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1.
Blaney Davidson EN Scharstuhl A Vitters EL van der Kraan PM van den Berg WB 《Arthritis research & therapy》2005,7(6):R1338-R1347
Osteoarthritis (OA) is a common joint disease, mainly effecting the elderly population. The cause of OA seems to be an imbalance
in catabolic and anabolic factors that develops with age. IL-1 is a catabolic factor known to induce cartilage damage, and
transforming growth factor (TGF)-beta is an anabolic factor that can counteract many IL-1-induced effects. In old mice, we
observed reduced responsiveness to TGF-beta-induced IL-1 counteraction. We investigated whether expression of TGF-beta and
its signaling molecules altered with age. To mimic the TGF-beta deprived conditions in aged mice, we assessed the functional
consequence of TGF-beta blocking. We isolated knee joints of mice aged 5 months or 2 years, half of which were exposed to
IL-1 by intra-articular injection 24 h prior to knee joint isolation. Immunohistochemistry was performed, staining for TGF-beta1,
-2 or -3, TGF-betaRI or -RII, Smad2, -3, -4, -6 and -7 and Smad-2P. The percentage of cells staining positive was determined
in tibial cartilage. To mimic the lack of TGF-beta signaling in old mice, young mice were injected with IL-1 and after 2 days
Ad-LAP (TGF-beta inhibitor) or a control virus were injected. Proteoglycan (PG) synthesis (35S-sulfate incorporation) and PG content of the cartilage were determined. Our experiments revealed that TGF-beta2 and -3 expression
decreased with age, as did the TGF-beta receptors. Although the number of cells positive for the Smad proteins was not altered,
the number of cells expressing Smad2P strongly dropped in old mice. IL-1 did not alter the expression patterns. We mimicked
the lack of TGF-beta signaling in old mice by TGF-beta inhibition with LAP. This resulted in a reduced level of PG synthesis
and aggravation of PG depletion. The limited response of old mice to TGF-beta induced-IL-1 counteraction is not due to a diminished
level of intracellular signaling molecules or an upregulation of intracellular inhibitors, but is likely due to an intrinsic
absence of sufficient TGF-beta receptor expression. Blocking TGF-beta distorted the natural repair response after IL-1 injection.
In conclusion, TGF-beta appears to play an important role in repair of cartilage and a lack of TGF-beta responsiveness in
old mice might be at the root of OA development. 相似文献
2.
Fushitani K; Higashiyama K; Moriyama EN; Imai K; Hosokawa K 《Molecular biology and evolution》1996,13(7):1039-1043
To elucidate phylogenetic relationships among amniotes and the evolution of
alpha globins, hemoglobins were analyzed from the Komodo dragon (Komodo
monitor lizard) Varanus komodoensis, the world's largest extant lizard,
inhabiting Komodo Islands, Indonesia. Four unique globin chains (alpha A,
alpha D, beta B, and beta C) were isolated in an equal molar ratio by high
performance liquid chromatography from the hemolysate. The amino acid
sequences of two alpha chains were determined. The alpha D chain has a
glutamine at E7 as does an alpha chain of a snake, Liophis miliaris, but
the alpha A chain has a histidine at E7 like the majority of hemoglobins.
Phylogenetic analyses of 19 globins including two alpha chains of Komodo
dragon and ones from representative amniotes showed the following results:
(1) The a chains of squamates (snakes and lizards), which have a glutamine
at E7, are clustered with the embryonic alpha globin family, which
typically includes the alpha D chain from birds; (2) birds form a sister
group with other reptiles but not with mammals; (3) the genes for embryonic
and adult types of alpha globins were possibly produced by duplication of
the ancestral alpha gene before ancestral amniotes diverged, indicating
that each of the present amniotes might carry descendants of the two types
of alpha globin genes; (4) squamates first split off from the ancestor of
other reptiles and birds.
相似文献
3.
本文用脑室灌注和Fura2测定细胞内游离钙技术观察了地塞米松(dexamethasone,DEX)对家兔乙二醇双(2氨基乙醚)四乙酸性发热效应和下丘脑细胞内游离钙浓度([Ca2+]i)的影响,借此深入探讨地塞米松解热作用的中枢机制。结果发现:脑室灌注乙二醇双(2氨基乙醚)四乙酸(06nmol)引起家兔结肠温度明显升高,静脉注射地塞米松(5mg/kg)显著抑制家兔乙二醇双(2氨基乙醚)四乙酸性发热,地塞米松(60~120μmol/L)并不影响下丘脑细胞内[Ca2+]i,而事先脑室灌注抑制基因转录的放线菌素D(3nmol)则完全取消了地塞米松对乙二醇双(2氨基乙醚)四乙酸性发热的解热作用。这些结果提示:地塞米松显著抑制家兔乙二醇双(2氨基乙醚)四乙酸性发热,其机制与地塞米松激活脑内某些基因的表达有关,而与下丘脑神经细胞跨膜钙离子流无关。 相似文献
4.
竹叶眼子菜(Potamogeton malaianus)、微齿眼子菜(Potamogeton maackianus)、苦草(Vallisneria spiralis)、穗花狐尾藻(Myriophyllum spicatum)、黑藻(Hydrilla verticillata)是长江中下游湖泊主要的沉水植物。在栽培条件下,它们的无性繁殖速率(单位时间内新增个体数)大小顺序为黑藻>微齿眼子菜>竹叶眼子菜>苦草>穗花狐尾藻。同时采用抛掷实验的方法观察研究了这5种沉水植物及其无性繁殖体的存活和生根情况;完整植株存活率为黑藻>穗花狐尾藻>微齿眼子菜>竹叶眼子菜>苦草,无性繁殖体部分存活率为黑藻>苦草>穗花狐尾藻>微齿眼子菜>竹叶眼子菜。生根能力和其存活时间长短相关,而且生根能力与存活率大小基本一致。在实验中,只有穗花狐尾藻的断枝存活率和生根能力存在差异,故无性繁殖体生根能力为黑藻>苦草>微齿眼子菜>竹叶眼子菜>穗花狐尾藻。 相似文献
5.
Matrix metalloproteinases (MMPs) degrade components of the extracellular matrix of the disc, but the presence of MMP-19 has not been explored. In other tissues, MMP-19 is known to act in proteolysis of the insulin-like growth factor (IGF) binding protein-3, thereby exposing this protein to make it available to influence cell behavior. MMP-19 also has been shown to inhibit capillary-like formation and thus play a role in the avascular nature of the disc. Using immunohistochemistry, normal discs from six subjects aged newborn through 10 years and 20 disc specimens from control donors or surgical patients aged 15-76 (mean age 40.2 years) were examined for immunolocalization of MMP-19; six Thompson grade I discs, five Thompson grade II, eight Thompson grade III, five Thompson grade IV, and one Thompson grade V discs were analyzed. The results indicate that in discs from young subjects, MMP-19 was uniformly localized in the outer annulus. In discs from adult donors and surgical patients, outer and inner annulus cells only occasionally showed MMP-19 localization. The greatest expression of MMP-19 was observed in young discs, and little expression was seen in older or degenerating discs. Because MMP-19 has been shown to regulate IGF-mediated proliferation in other tissues, its decline in the aging/degenerating disc may contribute to the age-related decrease in disc cell numbers. 相似文献
6.
Kitova EN Kitov PI Paszkiewicz E Kim J Mulvey GL Armstrong GD Bundle DR Klassen JS 《Glycobiology》2007,17(10):1127-1137
The binding stoichiometry and affinities of the Shiga toxins, Stx1 and Stx2, for a series of uni- and oligovalent analogs of the Pk-trisaccharide were measured using the direct electrospray ionization mass spectrometry (ES-MS) assay. Importantly, it is shown that, for a given ligand, Stx1 and Stx2 exhibit similar affinities. The binding data suggest a high degree of similarity in the spatial arrangement and structural characteristics of the Pk binding sites in Stx1 and Stx2. The results confirm that both toxins recognize the alpha-D-Galp(1-->4)-beta-D-Galp(1-->4)-beta-D-Glcp carbohydrate motif of the cell surface glycolipid Gb3. This, taken together with the results of the chemical mapping study, suggests that the nature of the Pk binding interactions with Stx1 and Stx2 are similar. The affinities of Stx1-B(5) and Stx2 for the multivalent ligands reveals that site 2 of Stx2, which shares the same spatial arrangement as site 2 in Stx1, is the primary Pk binding site and that site 1 of Stx1 and of Stx2 can also participate in Pk binding. 相似文献
7.
Tarasov S. E. Plekhanova Yu. V. Kitova A. E. Bykov A. G. Machulin A. V. Kolesov V. V. Klenova N. A. Revin V. V. Ponamoreva O. N. Reshetilov A. N. 《Applied Biochemistry and Microbiology》2022,58(4):468-477
Applied Biochemistry and Microbiology - Bacterial cellulose (BC) produced by the Komagateibacter sucrofermentas VKPM B-11267 bacteria was used as a carrier for immobilization of acetic acid... 相似文献
8.
Landscape-scale variation in the seed banks of floodplain wetlands with contrasting hydrology in China 总被引:3,自引:0,他引:3
1. At a local scale, the species composition, diversity and spatial variation of wetland plant communities are determined primarily by spatial and temporal heterogeneity in their environments. Less is known about variation at a landscape‐level. The floodplain of the Changjiang (Yangtze) River in China includes hydrologically connected, subtropical wetlands with different hydrological characteristics. 2. We examined seed‐bank species composition and richness in marshes of two contrasting hydrological types: permanent marshes, fed by local runoff, and lakeshore marshes more closely connected to the regulated river. Lakeshore marshes are flooded annually to depth of approximately 1 m and during flooding they support an alternate, aquatic vegetation type. The soil seed bank in March was a comparative estimator of species diversity. At the beginning of the growing season it included seeds from both phases of alternating vegetation types associated with the annual hydrological cycle. 3. A regional pool of 101 species was detected in the seed banks of six wetlands associated with the river and its tributaries: 56 occurred in permanent marshes and 59 in lakeshore marshes, with only 15 common to both. Species rarefaction curves indicated that more species occurred in permanent than lakeshore marshes at equal numbers of individuals sampled. However, the more heterogeneous lakeshore seed banks were estimated (Chao 2) to have greater total species richness (81) than permanent marsh (60). 4. Analysis using Sørensen's coefficient of similarity and DCA ordination revealed complex variation, with much greater differences between hydrological types than within them, irrespective of geographical distance. The types also differed significantly in the composition of four functional groups of species. 5. Despite the potential for dispersal of propagules via the annually pulsing river system (hydrochory), at a regional and landscape scale, diversity is maintained largely by large‐scale temporal hydrological heterogeneity and smaller scale spatial and topographic heterogeneity. 相似文献
9.
NMR spectroscopy was applied for studying the products of glucose and sorbitol oxidation by cells of Gluconobacter oxydans. An analysis of 1H NMR spectra showed that the transformation of glucose results in the formation of diketogluconic acid, and sorbitol is oxidized to sorbose. In the 32P NMR spectra, only a signal of inorganic phosphate was detected, which accumulated in the medium as a result of cell lysis. 相似文献
10.