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151.
Lucy J Leiper Petr Walczysko Romana Kucerova Jingxing Ou Lynne J Shanley Diane Lawson John V Forrester Colin D McCaig Min Zhao Martin J Collinson 《BMC biology》2006,4(1):27-14
Background
Congenital aniridia caused by heterozygousity at the PAX6 locus is associated with ocular surface disease including keratopathy. It is not clear whether the keratopathy is a direct result of reduced PAX6 gene dosage in the cornea itself, or due to recurrent corneal trauma secondary to defects such as dry eye caused by loss of PAX6 in other tissues. We investigated the hypothesis that reducing Pax6 gene dosage leads to corneal wound-healing defects. and assayed the immediate molecular responses to wounding in wild-type and mutant corneal epithelial cells. 相似文献152.
Solmi R. Rossetti A. Talassi O. Tomasini G. L. Fato R. Estornell E. Lucarini G. Lenaz G. Simonelli L. Brunelli M. A. Biagini G. 《Cytotechnology》1993,11(1):S59-S61
Gingival fibroblast cultures from four patients with Down's Syndrome (DS) and periodontal disease were compared with four in vitro age-matched fibroblast cultures of handicapped subjects (ND) also affected by periodontitis. The extra copy of cromosome 21 could alter growth regulation and biochemical mechanisms, so we examined quantitatively some DS phenotypical aspects to detect possible differences from those of controls. The growth properties of gingival fibroblast cultures from DS patients were more elevated than their ND age-matched controls. There were no differences in plasma membrane polarization and in neutral endopeptidase activity. The succinate-cytochrome C reductase activity decreases in DS fibroblasts compared with ND. Our results outline the difficulties to inusing fibroblast cultures as an in vitro system to study premature ageing Down's Syndrome. 相似文献
153.
AMPK is known to be activated by oxidative stress. Addition of glucose oxidase to cells generates H2O2 at a constant rate that is opposed by enzymic degradation, providing a good model for physiological oxidative stress. AMPK activation by glucose oxidase correlated with increases in cellular AMP:ATP and was greatly reduced in cells expressing an AMP-insensitive AMPK mutant, although a small degree of activation remained. The effects of increased AMP were partly due to inhibition of Thr172 dephosphorylation. These results suggest that changes in adenine nucleotides, rather than direct oxidative modification, are the major drivers of AMPK activation during oxidative stress. 相似文献
154.
We have investigated the production of reactive oxygen species (ROS) by Complex I in isolated open bovine heart submitochondrial membrane fragments during forward electron transfer in presence of NADH, by means of the probe 2′,7′-Dichlorodihydrofluorescein diacetate. ROS production by Complex I is strictly related to its inhibited state. Our results indicate that different Complex I inhibitors can be grouped into two classes: Class A inhibitors (Rotenone, Piericidin A and Rolliniastatin 1 and 2) increase ROS production; Class B inhibitors (Stigmatellin, Mucidin, Capsaicin and Coenzyme Q2) prevent ROS production also in the presence of Class A inhibitors. Addition of the hydrophilic Coenzyme Q1 as an electron acceptor potentiates the effect of Rotenone-like inhibitors in increasing ROS production, but has no effect in the presence of Stigmatellin-like inhibitors; the effect is not shared by more hydrophobic quinones such as decyl-ubiquinone. This behaviour relates the prooxidant CoQ1 activity to a hydrophilic electron escape site. Moreover the two classes of Complex I inhibitors have an opposite effect on the increase of NADH-DCIP reduction induced by short chain quinones: only Class B inhibitors allow this increase, indicating the presence of a Rotenone-sensitive but Stigmatellin-insensitive semiquinone species in the active site of the enzyme. The presence of this semiquinone was also suggested by preliminary EPR data. The results suggest that electron transfer from the iron-sulphur clusters (N2) to Coenzyme Q occurs in two steps gated by two different conformations, the former being sensitive to Rotenone and the latter to Stigmatellin. 相似文献
155.
The variation in tenacity of single tube feet from three sea urchin species with contrasted habitats was assessed and correlated with the ultrastructure of their adhesive secretory granules. The tube feet of Arbacia lixula and Sphaerechinus granularis have larger discs and more complex adhesive granules than those of Paracentrotus lividus, but A. lixula attaches to glass with significantly lower tenacity (0.05-0.09 MPa) than the other two species (0.10-0.20 and 0.11 -0.29 MPa, respectively). However, the estimated maximal attachment force one tube foot can produce is similar for all three species investigated. No clear relationship between tube foot size, tenacity, adhesive secretory granule ultrastructure and species habitat can therefore be established. For P. lividus the tenacity of single tube foot discs on four different smooth substrata was also compared, which showed that both the total surface energy and the ratio of polar to non-polar forces at the surface influence tube foot attachment strength. This influence of the surface characteristics of the substratum appears to affect the cohesiveness of the adhesive secretion more than its adhesiveness. 相似文献
156.
Pavel Macek Josef Chmelík Ivana K?í?ová Pavel Kade?ávek Lukáš ?ídek Romana Hadravová Iva Pichová Michaela Rumlová Vladimír Sklená? 《Journal of molecular biology》2009,392(1):100-652
The high-resolution structure of the N-terminal domain (NTD) of the retroviral capsid protein (CA) of Mason-Pfizer monkey virus (M-PMV), a member of the betaretrovirus family, has been determined by NMR. The M-PMV NTD CA structure is similar to the other retroviral capsid structures and is characterized by a six α-helix bundle and an N-terminal β-hairpin, stabilized by an interaction of highly conserved residues, Pro1 and Asp57. Since the role of the β-hairpin has been shown to be critical for formation of infectious viral core, we also investigated the functional role of M-PMV β-hairpin in two mutants (i.e., ΔP1NTDCA and D57ANTDCA) where the salt bridge stabilizing the wild-type structure was disrupted. NMR data obtained for these mutants were compared with those obtained for the wild type. The main structural changes were observed within the β-hairpin structure; within helices 2, 3, and 5; and in the loop connecting helices 2 and 3. This observation is supported by biochemical data showing different cleavage patterns of the wild-type and the mutated capsid-nucleocapsid fusion protein (CANC) by M-PMV protease. Despite these structural changes, the mutants with disrupted salt bridge are still able to assemble into immature, spherical particles. This confirms that the mutual interaction and topology within the β-hairpin and helix 3 might correlate with the changes in interaction between immature and mature lattices. 相似文献
157.
158.
Nintasen R Riches K Mughal RS Viriyavejakul P Chaisri U Maneerat Y Turner NA Porter KE 《Biochemical and biophysical research communications》2012,420(4):828-833
Coronary heart disease (CHD) is a condition characterized by increased levels of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α). TNF-α can induce vascular endothelial cell (EC) and smooth muscle cell (SMC) dysfunction, central events in development of neointimal lesions. The reduced incidence of CHD in young women is believed to be due to the protective effects of estradiol (E2). We therefore investigated the effects of TNF-α on human neointima formation and SMC/EC functions and any modulatory effects of E2. Saphenous vein (SV) segments were cultured in the presence of TNF-α (10 ng/ml), E2 (2.5 nM) or both in combination. Neointimal thickening was augmented by incubation with TNF-α, an effect that was abolished by co-culture with E2. TNF-α increased SV-SMC proliferation in a concentration-dependent manner that was optimal at 10 ng/ml (1.5-fold increase), and abolished by E2 at all concentrations studied (1-50 nM). Surprisingly, E2 itself at low concentrations (1 and 5 nM) stimulated SV-SMC proliferation to a level comparable to that of TNF-α alone. SV-EC migration was significantly impaired by TNF-α (42% of control), and co-culture with E2 partially restored the ability of SV-EC to migrate and repair the wound. In contrast, TNF-α increased SV-SMC migration by 1.7-fold, an effect that was completely reversed by co-incubation with E2. Finally, TNF-α potently induced ICAM-1 and VCAM-1 expression in both SV-EC and SV-SMC. However there was no modulation by E2 in either cell-type. In conclusion, TNF-α induced SV neointima formation, increased SMC proliferation and migration, impaired SV-EC migration and increased expression of adhesion molecules. E2 exerted distinct cell-type and function-specific modulation, the mechanisms underlying which are worthy of further detailed study. 相似文献
159.
160.
Plant Ecology - Lowland forests in Europe went through dramatic changes in the last century. Data accumulated from the nature reserve Buky u Vysokého Chvojna in the Czech Republic provide a... 相似文献