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81.
Yumiko I. Matsuishi Hiroki Kato Keiji Masuda Haruyoshi Yamaza Yuta Hirofuji Hiroshi Sato Hiroko Wada Tamotsu Kiyoshima Kazuaki Nonaka 《Biochemical and biophysical research communications》2018,495(2):1655-1660
Undifferentiated odontogenic epithelium and dental papilla cells differentiate into ameloblasts and odontoblasts, respectively, both of which are essential for tooth development. These differentiation processes involve dramatic functional and morphological changes of the cells. For these changes to occur, activation of mitochondrial functions, including ATP production, is extremely important. In addition, these changes are closely related to mitochondrial fission and fusion, known as mitochondrial dynamics. However, few studies have focused on the role of mitochondrial dynamics in tooth development. The purpose of this study was to clarify this role. We used mouse tooth germ organ cultures and a mouse dental papilla cell line with the ability to differentiate into odontoblasts, in combination with knockdown of the mitochondrial fission factor, dynamin related protein (DRP)1. In organ cultures of the mouse first molar, tooth germ developed to the early bell stage. The amount of dentin formed under DRP1 inhibition was significantly larger than that of the control. In experiments using a mouse dental papilla cell line, differentiation into odontoblasts was enhanced by inhibiting DRP1. This was associated with increased mitochondrial elongation and ATP production compared to the control. These results suggest that DRP1 inhibition accelerates dentin formation through mitochondrial elongation and activation. This raises the possibility that DRP1 might be a therapeutic target for developmental disorders of teeth. 相似文献
82.
83.
Itoh Hiroya Miura Ai Matsui Makoto Arazoe Takayuki Nishida Keiji Kumagai Toshitaka Arita Masanori Tamano Koichi Machida Masayuki Shibata Takashi 《Applied microbiology and biotechnology》2018,102(3):1393-1405
Applied Microbiology and Biotechnology - In the production of useful microbial secondary metabolites, the breeding of strains is generally performed by random mutagenesis. However, because random... 相似文献
84.
Shinozaki F Minami M Chiba T Suzuki M Yoshimatsu K Ichikawa Y Terasawa K Emori Y Matsumoto K Kurosaki T Nakai A Tanaka K Minami Y 《The Journal of biological chemistry》2006,281(24):16361-16369
Hsp90 participates in many distinct aspects of cellular functions and accomplishes these roles by interacting with multiple client proteins. To gain insight into the interactions between Hsp90 and its clients, here we have reduced the protein level of Hsp90 in avian cells by gene targeting in an attempt to elicit the otherwise undetectable (because of the vast amount of cellular Hsp90) Hsp90-interacting proteins. Hsp90beta-deficient cells can grow, albeit more slowly than wild-type cells. B cell antigen receptor signaling is multiply impaired in these mutant cells; in particular, the amount of immunoglobulin M heavy chain protein is markedly reduced. Furthermore, serum activation does not promote ERK phosphorylation in Hsp90beta-deficient cells. These multifaceted depressive effects seem to be provoked independently of each other and possibly recapitulate the proteome-wide in vivo functions of Hsp90. Reintroduction of the Hsp90beta gene efficiently restores all of the defects. Unexpectedly, however, introducing the Hsp90alpha gene is also effective in restoration; thus, these defects might be caused by a reduction in the total expression of Hsp90 rather than by loss of Hsp90beta-specific function. 相似文献
85.
Tadashi Miyashita Maki Suzuki Mayura Takada Go Fujita Keiji Ochiai Masahiko Asada 《Population Ecology》2007,49(3):185-190
Evaluating the quality of wildlife habitat is essential for understanding and predicting population dynamics in heterogeneous
environments. We used fecal nitrogen levels as an indicator of habitat quality of sika deer (Cervus nippon) and explored important landscape elements influencing nitrogen levels, taking deer density into account. We established
92 plots differing in deer density and landscape structure on the Boso Peninsula, central Japan, and collected fecal samples
along a 1-km transect at each plot. The regression models involving two independent variables, i.e., deer density and the
length of forest edge within an area of 100 or 200 m from the transect, were selected based on the Akaike’s Information Criterion
(AIC). Levels of fecal nitrogen were positively correlated with the length of the forest edge and negatively correlated with
population density of deer. The area of 100 or 200 m from the transect most likely reflected the behavioral scale of the deer.
Coverage of palatable understory vegetation increased with proximity to forest edge and decreased with deer density. Variability
in the level of fecal nitrogen could thus be explained by food availability in the landscape. These results suggest that landscape
alterations increase the carrying capacity of sika deer and thereby increase impacts upon the ecosystem. 相似文献
86.
Kajiya M Hirota M Inai Y Kiyooka T Morimoto T Iwasaki T Endo K Mohri S Shimizu J Yada T Ogasawara Y Naruse K Ohe T Kajiya F 《American journal of physiology. Heart and circulatory physiology》2007,292(6):H2737-H2744
Pulmonary hypertension (PH) causes right ventricular (RV) hypertrophy and, according to the extent of pressure overload, eventual heart failure. We tested the hypothesis that the mechanical stress in PH-RV impairs the vasoreactivity of the RV coronary microvessels of different sizes with increased superoxide levels. Five-week-old male Sprague-Dawley rats were injected with monocrotaline (n=126) to induce PH or with saline as controls (n=114). After 3 wk, coronary arterioles (diameter = 30-100 microm) and small arteries (diameter = 100-200 microm) in the RV were visualized using intravital videomicroscopy. We evaluated ACh-induced vasodilation alone, in the presence of N(omega)-nitro-L-arginine methyl ester (L-NAME), in the presence of tetraethylammonium (TEA) or catalase with or without L-NAME, and in the presence of SOD. The degree of suppression in vasodilation by L-NAME and TEA was used as indexes of the contributions of endothelial nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF), respectively. In PH rats, ACh-induced vasodilation was significantly attenuated in both arterioles and small arteries, especially in arterioles. This decreased vasodilation was largely attributable to reduced NO-mediated vasoreactivity, whereas the EDHF-mediated vasodilation was relatively robust. The suppressive effect on arteriolar vasodilation by catalase was similar to TEA in both groups. Superoxide, as measured by lucigenin chemiluminescence, was significantly elevated in the RV tissues in PH. SOD significantly ameliorated the impairment of ACh-induced vasodilation in PH. Robust EDHF function will play a protective role in preserving coronary microvascular homeostasis in the event of NO dysfunction with increased superoxide levels. 相似文献
87.
Hirano Y Kaneko T Okamoto K Bai M Yashiroda H Furuyama K Kato K Tanaka K Murata S 《The EMBO journal》2008,27(16):2204-2213
The 20S proteasome is the catalytic core of the 26S proteasome. It comprises four stacked rings of seven subunits each, alpha(1-7)beta(1-7)beta(1-7)alpha(1-7). Recent studies indicated that proteasome-specific chaperones and beta-subunit appendages assist in the formation of alpha-rings and dimerization of half-proteasomes, but the process involved in the assembly of beta-rings is poorly understood. Here, we clarify the mechanism of beta-ring formation on alpha-rings by characterizing assembly intermediates accumulated in cells depleted of each beta-subunit. Starting from beta2, incorporation of beta-subunits occurs in an orderly manner dependent on the propeptides of beta2 and beta5, and the C-terminal tail of beta2. Unexpectedly, hUmp1, a chaperone functioning at the final assembly step, is incorporated as early as beta2 and is required for the structural integrity of early assembly intermediates. We propose a model in which beta-ring formation is assisted by both intramolecular and extrinsic chaperones, whose roles are partially different between yeast and mammals. 相似文献
88.
Recessive Nonsense Suppressors in SACCHAROMYCES CEREVISIAE : Action Spectra, Complementation Groups and Map Positions 总被引:1,自引:3,他引:1 下载免费PDF全文
Bun-Ichiro Ono Yumiko Ishino-Arao Masahiro Tanaka Ikuko Awano Sumio Shinoda 《Genetics》1986,114(2):363-374
Three genes SUP111, SUP112 and SUP113 of Saccharomyces cerevisiae have been identified that can mutate to give recessive omnipotent nonsense suppressors. Alleles of these loci can also act as allosuppressors; that is, different phenotypes, due apparently to different efficiencies of suppression, can result from different alleles at a given locus. The SUP111, SUP112 and SUP113 loci map to the right arms of chromosomes VIII, VII and XIII, respectively. 相似文献
89.
Laboratory experiments were carried out to investigate byssal thread production by the intertidal mytilid mussel Hormomya mutabilis in response to effluent from the predatory crab Eriphia smithii and the starfish Coscinasterias acutispina. During the early period of the experiment, large H. mutabilis exposed to crab effluent produced a significantly smaller number of functional byssal threads than mussels in crab-free water.
No significant difference in the diameter of threads produced in the two treatments was detected. The number of functional
byssal threads produced by small H. mutabilis exposed to crab effluent did not differ significantly from that of mussels in crab-free water. However, small H. mutabilis exposed to crab effluent tended to discard fewer byssal bundles, that is, they shifted their attaching sites less frequently
than similar mussels in crab-free water. In the presence of waterborne cues from the crab, H. mutabilis tended to reduce both the secretion of byssal threads and movement across the substratum. No significant differences in behaviour
were observed between large mussels exposed to effluent from the starfish and those unexposed. The adaptive significance of
the responses shown by H. mutabilis is discussed in terms of protection against predators differing in foraging behaviour.
Electronic Publication 相似文献
90.
Takeshita H Kitano M Iwasaki T Kitano S Tsunemi S Sato C Sekiguchi M Azuma N Miyazawa K Hla T Sano H 《Biochemical and biophysical research communications》2012,419(2):154-159
Sphingosine 1-phosphate (S1P)/S1P receptor 1 (S1P1) signaling plays an important role in synovial cell proliferation and inflammatory gene expression by rheumatoid arthritis (RA) synoviocytes. The purpose of this study is to clarify the role of S1P/S1P1 signaling in the expression of receptor activator of NF-κB ligand (RANKL) in RA synoviocytes and CD4(+) T cells. We demonstrated MH7A cells, a human RA synovial cell line, and CD4(+) T cells expressed S1P1 and RANKL. Surprisingly, S1P increased RANKL expression in MH7A cells and CD4(+) T cells in a dose-dependent manner. Moreover, S1P enhanced RANKL expression induced by stimulation with TNF-α in MH7A cells and CD4(+) T cells. These effects of S1P in MH7A cells were inhibited by pretreatment with PTX, a specific Gi/Go inhibitor. These findings suggest that S1P/S1P1 signaling may play an important role in RANKL expression by MH7A cells and CD4(+) T cells. S1P/S1P1 signaling of RA synoviocytes is closely connected with synovial hyperplasia, inflammation, and RANKL-induced osteoclastogenesis in RA. Thus, regulation of S1P/S1P1 signaling may become a novel therapeutic target for RA. 相似文献