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91.
92.
Introduction
Although transforming growth factor β1 (TGFβ1) is known to be a potent inhibitor of proliferation in most cell types, it accelerates proliferation in certain mesenchymal cells, such as articular chondrocytes and nucleus pulposus cells. The low ability for self-renewal of nucleus pulposus cells is one obstacle in developing new therapeutic options for intervertebral disc diseases, and utilizing cytokines is one of the strategies to regulate nucleus pulposus cell proliferation. However, the precise cell cycle progression and molecular mechanisms by which TGFβ1 stimulates cell growth remain unclear. The aim of this study was to elucidate a mechanism that enables cell proliferation with TGFβ1 stimulation. 相似文献93.
Joji Mima 《Biophysical reviews》2021,13(4):531
Small GTPases of the Ras superfamily, which include Ras-, Rho-, Rab-, Arf-, and Ran-family isoforms, are generally known to function as a nucleotide-dependent molecular switch in eukaryotic cells. In the GTP-loaded forms, they selectively recruit their cognate interacting proteins or protein complexes, termed “effectors,” to the cytoplasmic face of subcellular membrane compartments, thereby switching on the downstream effector functions, which are vital for fundamental cellular events, such as cell proliferation, cytoskeletal organization, and intracellular membrane trafficking. Nevertheless, in addition to acting as the classic nucleotide-dependent switches for the effectors, recent studies have uncovered that small GTPases themselves can be self-assembled specifically into homo-dimers or higher-order oligomers on membranes, and these assembly processes are likely responsible for their physiological functions. This Review focuses particularly on the self-assembly processes of Rab- and Arf-family isoforms during membrane tethering, the most critical step to ensure the fidelity of membrane trafficking. A summary of the current experimental evidence for self-assemblies of Rab and Arf small GTPases on lipid bilayers in chemically defined reconstitution system is provided 相似文献
94.
Kazuhiko Mochida Katsutoshi Ito Hiroya Harino Hiroyuki Tanaka Toshimitsu Onduka Akira Kakuno Kazunori Fujii 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2009,149(4):624-630
In a previous study, we demonstrated that exposure to an antifouling biocide, copper pyrithione (CuPT), early during life induced vertebral deformity in the larvae of a marine fish, the mummichog (Fundulus heteroclitus). Skeletal deformities may be caused by inhibition by of acetylcholiensterase (AChE) activity, and to elucidate the mechanism underlying the CuPT-associated vertebral deformity, we first examined whether CuPT, zinc pyrithione (ZnPT), and their degradation products could inhibit AChE activity in the fish. Two of the degradation products, 2,2′-dipyridyldisulfide [(PS)2] and 2,2′-dithiobispyridine-N-oxide [(PT)2], but neither CuPT nor ZnPT, exhibited prominent AChE-inhibiting activity. Secondly, thin-layer chromatography revealed that mummichog hepatic microsomes metabolized CuPT to produce (PS)2 in a microsome-dependent manner. The AChE inhibition induced in CuPT-exposed fish is likely due to (PS)2 that was produced through metabolism of acquired CuPT. (PS)2 may cause therefore skeletal deformity in CuPT-exposed fish by means of its neuromuscular blocking properties, through a mechanism similar to that proposed for animals exposed to organophosphorous pesticides. 相似文献
95.
Background
Many butterfly species have been experiencing the northward range expansion and physiological adaptation, probably due to climate warming. Here, we document an extraordinary field case of a species of lycaenid butterfly, Zizeeria maha, for which plastic phenotypes of wing color-patterns were revealed at the population level in the course of range expansion. Furthermore, we examined whether this outbreak of phenotypic changes was able to be reproduced in a laboratory. 相似文献96.
Species‐dependent microarchitectural traits of iridescent scales in the triad taxa of Ornithoptera birdwing butterflies
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Makoto Kazama Mai Ichinei Saori Endo Masaki Iwata Akiya Hino Joji M. Otaki 《Entomological Science》2017,20(1):255-269
Ornithoptera birdwing butterflies have blue, green, or orange iridescent scales in different species or subspecies. To understand the species‐ or subspecies‐dependent scale color differences, we performed comparative morphometric analyses of iridescent scales from three closely related taxa: O. priamus priamus (green), O. priamus urvillianus (blue), and O. croesus (orange). The three types of Ornithoptera wings exhibited reversible color changes to longer wavelengths with different kinetics upon immersion in methanol, suggesting that their color differences are at least partly based on differences in the size of air cavities made by nanostructures. Cover scales of all three color types were visually semi‐transparent glass scales that exhibited color when placed on a dark background. The dorsoventral differences in coloration were observed in single scales, suggesting the optical importance of scale surfaces. Scanning electron microscopy of cover scales in cross section revealed that all color types exhibited finely sculpted tapered ridges and thick, irregular basal multilayers containing tandemly clustered granular objects and air cavities. Scale thickness, ridge height, and multilayer thickness were significantly different among the three color types, and granular object size was significantly different between orange scales and blue and green scales. We conclude that each of the three taxa of Ornithoptera butterflies possesses unique quantitative size values on tapered ridges and irregular multilayers with granular objects and air cavities to express unique structural color. These species‐ or subspecies‐dependent structural colors might have evolved via quantitative shifts in these microarchitectural traits rather than via changes in the basic developmental or architectural plan for color expression. 相似文献
97.
Essential role of tissue-specific proline synthesis and catabolism in growth and redox balance at low water potential 总被引:2,自引:0,他引:2
To better define the still unclear role of proline (Pro) metabolism in drought resistance, we analyzed Arabidopsis (Arabidopsis thaliana) Δ(1)-pyrroline-5-carboxylate synthetase1 (p5cs1) mutants deficient in stress-induced Pro synthesis as well as proline dehydrogenase (pdh1) mutants blocked in Pro catabolism and found that both Pro synthesis and catabolism were required for optimal growth at low water potential (ψ(w)). The abscisic acid (ABA)-deficient mutant aba2-1 had similar reduction in root elongation as p5cs1 and p5cs1/aba2-1 double mutants. However, the reduced growth of aba2-1 but not p5cs1/aba2-1 could be complemented by exogenous ABA, indicating that Pro metabolism was required for ABA-mediated growth protection at low ψ(w). PDH1 maintained high expression in the root apex and shoot meristem at low ψ(w) rather than being repressed, as in the bulk of the shoot tissue. This, plus a reduced oxygen consumption and buildup of Pro in the root apex of pdh1-2, indicated that active Pro catabolism was needed to sustain growth at low ψ(w). Conversely, P5CS1 expression was most highly induced in shoot tissue. Both p5cs1-4 and pdh1-2 had a more reduced NADP/NADPH ratio than the wild type at low ψ(w). These results indicate a new model of Pro metabolism at low ψ(w) whereby Pro synthesis in the photosynthetic tissue regenerates NADP while Pro catabolism in meristematic and expanding cells is needed to sustain growth. Tissue-specific differences in Pro metabolism and function in maintaining a favorable NADP/NADPH ratio are relevant to understanding metabolic adaptations to drought and efforts to enhance drought resistance. 相似文献
98.
99.
Honda K Okamoto K Mochida Y Ishioka K Oka M Maesato K Ikee R Moriya H Hidaka S Ohtake T Doi K Fujita T Kobayashi S Noiri E 《American journal of physiology. Cell physiology》2011,301(6):C1423-C1430
Maggot debridement therapy (MDT) is effective for treating intractable wounds, but its precise molecular mechanism, including the association between MDT and growth factors, remains unknown. We administered MDT to nine patients (66.3 ± 11.8 yr, 5 male and 4 female) with intractable wounds of lower extremities because they did not respond to conventional therapies. Significant increases of hepatocyte growth factor (HGF) levels were observed in femoral vein blood during 48 h of MDT (P < 0.05), but no significant change was found for vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), transforming growth factor-β1 (TGF-β1), or tumor necrosis factor-α (TNF-α). We conducted NIH-3T3 cell stimulation assay to evaluate the relation between HGF and protease activity in excretion/secretion (ES) derived from maggots. Compared with the control group, HGF was significantly higher in the 0.05 μg/ml ES group (P < 0.01). Furthermore, protease inhibitors suppressed the increase of HGF (P < 0.05). The HGF expression was increased in proportion to the ES protein concentration of 0.025 to 0.5 μg/ml. In fact, ES showed stronger capability of promoting HGF production and less cytotoxicity than chymotrypsin or bromelain. HGF is an important factor involved in cutaneous wound healing. Therefore, these results suggest that formation of healthy granulation tissue observed during MDT results from the increased HGF. Further investigation to identify molecules enhancing HGF expression by MDT will contribute greatly to drug target discovery for intractable wound healing therapy. 相似文献
100.
Lakshmi Mahadevan Ancy Yesudas P. K. Sajesh S. Revu Prasanna Kumar Devi Santhosh Sam Santhosh J. M. Sashikumar V. K. Gopalakrishnan Joji Boben Changanamkandath Rajesh 《Indian journal of human genetics》2014,20(2):175-184