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81.
Watanabe M Ohshima M Morohashi M Maéno M Izutsu Y 《Development, growth & differentiation》2003,45(1):77-84
Results from previous studies using an inbred strain of Xenopus laevis have led to the proposition that metamorphosis includes the events by which the newly differentiating adult immune system, including T lymphocytes, recognizes and eliminates larval skin cells as 'non-self'. More recently, a larval antigen targeted by adult T cells was identified as a 59 kDa protein with a specific peptide sequence. Using antisera directed against the larval antigen and the peptide, immunohistochemistry and western blotting were done to examine expression of the 59 kDa larval antigen in the skin during larval and metamorphic periods. There was no expression before Nieuwkoop and Faber stage 53. Expression was first seen at the beginning of metamorphic stage 54, when hind limbs appear, and increased thereafter, in apical and skein cells of both trunk and tail regions. In the trunk region, expression started to decrease at stage 58, until it completely disappeared at stage 62 (metamorphic climax). In the tail skin, however, expression persisted throughout the metamorphic stages. Treatment of larvae with thyroid hormone (TH) resulted in repression of expression of the 59 kDa molecule in a dose-dependent manner. Downregulation occurred earlier in the trunk than in the tail skin. These results suggest involvement in metamorphic events of an immunological mechanism: differential expression of the larval antigen in the trunk and tail skin cells due to their differing concentration of TH results in the tail, but not the trunk skin, being selectively attacked by the newly differentiating adult-type immune system. 相似文献
82.
Growth and differentiation potential of main- and side-population cells derived from murine skeletal muscle 总被引:9,自引:0,他引:9
Tamaki T Akatsuka A Okada Y Matsuzaki Y Okano H Kimura M 《Experimental cell research》2003,291(1):83-90
Skeletal muscle-derived CD34+/45- (Sk-34) cells were identified as a new candidate for stem cells. However, the relationship between Sk-34 cells and side-population (SP) cells is unknown. Here, we demonstrate that Sk-34 cells prepared from murine skeletal muscles consist wholly of main-population (MP) cells. The Sk-34 cells included only a few SP cells (1:1000, SP:MP). Colony-forming units of Sk-34 cells of both SP and MP possessed the same potential to differentiate into adipocytes, endothelial, and myogenic cells and showed the same colony-forming activity (1.6%). In addition, the colony-forming units of the CD34-/45- (double negative: DN) population were found to begin CD34 expression and to possess the potential to differentiate into myogenic and endothelial cells. We also found that expression of CD34 antigen precedes MyoD expression during the myogenic process of DN cells. Furthermore, both Sk-34 and DN cell populations were mostly negative for CD73 (93-95%), whereas the CD45+ cell population was >25% positive for CD73, and this trend was also seen in bone marrow-derived CD45+ cells. These results indicate that the MP cell population is about 99.9% responsible for the reported in vitro myogenic-endothelial responses of skeletal muscle-derived cells. 相似文献
83.
Fas is the death receptor, transducing cell death signaling upon stimulation by Fas ligand. During Fas-initiated cell death signaling, the formation of Fas-death inducing signaling complex (Fas-DISC) is the first step. Here we have identified a new component of Fas-DISC which we call 'small-accelerator for death signaling' (SADS). SADS cDNA encodes a 150 amino acid polypeptide (Mr = 16,700). During Fas-mediated cell death, SADS enhances the interaction of Fas-death domain-interactive factors (FADD) and procaspase-8, and deletion mutant analysis has identified FADD- and caspase-8-interactive domains in SADS. Inhibition or removal of SADS delays Fas-mediated cell death. In addition, we demonstrate the deletion or mutation of SADS in patients with colon carcinoma and that exogenous SADS expression in human colon carcinoma SW480 cells that lack SADS leads to re-acquisition of Fas-mediated cell death. Here, we propose that SADS is one of the cell death-associated factors and enhances Fas-DISC formation, especially FADD and procaspase-8 recruitment. 相似文献
84.
85.
Takeuchi H Fujiyuki T Shirai K Matsuo Y Kamikouchi A Fujinawa Y Kato A Tsujimoto A Kubo T 《FEBS letters》2002,513(2-3):230-234
To clarify the molecular basis underlying the neural function of the honeybee mushroom bodies (MBs), we identified three genes preferentially expressed in MB using cDNA microarrays containing 480 differential display-positive candidate cDNAs expressed locally or differentially, dependent on caste/aggressive behavior in the honeybee brain. One of the cDNAs encodes a putative type I inositol 1,4,5-trisphosphate (IP(3)) 5-phosphatase and was expressed preferentially in one of two types of intrinsic MB neurons, the large-type Kenyon cells, suggesting that IP(3)-mediated Ca(2+) signaling is enhanced in these neurons. 相似文献
86.
Ukeda H Hasegawa Y Harada Y Sawamura M 《Bioscience, biotechnology, and biochemistry》2002,66(1):36-43
Glycolaldehyde, an intermediate of the Maillard reaction, and fructose, which is mainly derived from the polyol pathway, rapidly inactivate human Cu,Zn-superoxide dismutase (SOD) at the physiological concentration. We employed this inactivation with these carbonyl compounds as a model glycation reaction to investigate whether carnosine and its related compounds could protect the enzyme from inactivation. Of eight derivatives examined, histidine, Gly-His, carnosine and Ala-His inhibited the inactivation of the enzyme by fructose (p<0.001), and Gly-His, Ala-His, anserine, carnosine, and homocarnosine exhibited a marked protective effect against the inactivation by glycolaldehyde (p<0.001). The carnosine-related compounds that showed this highly protective effect against the inactivation by glycolaldehyde had high reactivity with glycolaldehyde and high scavenging activity toward the hydroxyl radical as common properties. On the other hand, the carnosine-related compounds that had a protective effect against the inactivation by fructose showed significant hydroxyl radical-scavenging ability. These results indicate that carnosine and such related compounds as Gly-His and Ala-His are effective anti-glycating agents for human Cu,Zn-SOD and that the effectiveness is based not only on high reactivity with carbonyl compounds but also on hydroxyl radical scavenging activity. 相似文献
87.
Matsui T Kobayashi M Hayashida S Matsumoto K 《Bioscience, biotechnology, and biochemistry》2002,66(3):689-692
In order to clarify the postprandial glucose suppression via alpha-glucosidase (AGH) inhibitory action by natural compounds, flavonoids were examined in this study. Among the flavonoids (luteolin, kaempferol, chrysin, and galangin), luteolin showed the potent maltase inhibitory activity with the IC50 of 2.3 mM, while less inhibitions were observed against sucrase. In addition, the effects of maltase inhibition by flavonoids were observed in the descending order of potency of luteolin > kaempferol > chrysin > galangin. Apparently, the AGH inhibition power greatly increased with the replacement of hydroxyl groups at 3' and 4'-position of the B-ring. However, the inhibitory power of luteolin was poorer than a therapeutic drug (acarbose: IC50; 430 nM). As a result of a single oral administration of maltose or sucrose (2 g/kg) in SD rats, no significant change in blood glucose level with the doses of 100 and 200 mg/kg of luteolin was observed. These findings strongly suggested that luteolin given at less than 200 mg/kg did not possess the ability to suppress the glucose production from carbohydrates through the inhibition of AGH action in the gut. 相似文献
88.
CHO1, a mammalian kinesin-like protein, interacts with F-actin and is involved in the terminal phase of cytokinesis 总被引:5,自引:0,他引:5 下载免费PDF全文
CHO1 is a kinesin-like protein of the mitotic kinesin-like protein (MKLP)1 subfamily present in central spindles and midbodies in mammalian cells. It is different from other subfamily members in that it contains an extra approximately 300 bp in the COOH-terminal tail. Analysis of the chicken genomic sequence showed that heterogeneity is derived from alternative splicing, and exon 18 is expressed in only the CHO1 isoform. CHO1 and its truncated isoform MKLP1 are coexpressed in a single cell. Surprisingly, the sequence encoded by exon 18 possesses a capability to interact with F-actin, suggesting that CHO1 can associate with both microtubule and actin cytoskeletons. Microinjection of exon 18-specific antibodies did not result in any inhibitory effects on karyokinesis and early stages of cytokinesis. However, almost completely separated daughter cells became reunited to form a binulceate cell, suggesting that the exon 18 protein may not have a role in the formation and ingression of the contractile ring in the cortex. Rather, it might be involved directly or indirectly in the membrane events necessary for completion of the terminal phase of cytokinesis. 相似文献
89.
Yamada M Tohno Y Takakura Y Tohno S Moriwake Y Minami T 《Biological trace element research》2003,91(1):57-66
To elucidate compositional changes of the tendons with aging, the authors investigated age-related changes of element contents
in the tendon of the iliopsoas muscle by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of
14 men and 14 women, ranging in age from 4 to 102 yr. The insertion tendons of the iliopsoas were removed from the cadavers
after ordinary dissection and also surgically from patients with congenital dislocation of the hip. It was found that both
Mg and P in the tendon of the iliopsoas muscle increased significantly with aging, but the other elements, such as S, Ca,
Na, Zn, Fe, and Si, hardly changed with aging.
With regard to the relationship among element contents, extremely significant correlations were found between P and S contents,
between Mg and Na contents, and between S and Zn contents. In addition, very significant correlations were found between Si
and either S or Zn contents. However, there was no significant correlation between Ca and P contents. These results revealed
that with regard to age-related changes of element contents and the relationships among element contents, the tendon of the
iliopsoas muscle was different from the Achilles tendon, in which both Mg and P decreased significantly with aging and there
were significant correlations each other among the contents of S, Mg, and P. 相似文献
90.
The novel gene, gamma2-COP (COPG2), in the 7q32 imprinted domain escapes genomic imprinting 总被引:5,自引:0,他引:5
Yamasaki K Hayashida S Miura K Masuzaki H Ishimaru T Niikawa N Kishino T 《Genomics》2000,68(3):330-335