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排序方式: 共有3499条查询结果,搜索用时 312 毫秒
991.
Sei-Young Lim Kosuke Yamaguchi Masanori Itakura Miho Chikazawa Tomonari Matsuda Koji Uchida 《The Journal of biological chemistry》2022,298(2)
Lysine N-pyrrolation, a posttranslational modification, which converts lysine residues to Nε-pyrrole-L-lysine, imparts electronegative properties to proteins, causing them to mimic DNA. Apolipoprotein E (apoE) has been identified as a soluble receptor for pyrrolated proteins (pyrP), and accelerated lysine N-pyrrolation has been observed in apoE-deficient (apoE−/−) hyperlipidemic mice. However, the impact of pyrP accumulation consequent to apoE deficiency on the innate immune response remains unclear. Here, we investigated B-1a cells known to produce germline-encoded immunoglobulin M (IgM) from mice deficient in apoE and identified a particular cell population that specifically produces IgM antibodies against pyrP and DNA. We demonstrated an expansion of B-1a cells involved in IgM production in the peritoneal cavity of apoE−/− mice compared with wild-type mice, consistent with a progressive increase of IgM response in the mouse sera. We found that pyrP exhibited preferential binding to B-1a cells and facilitated the production of IgM. B cell receptor analysis of pyrP-specific B-1a cells showed restricted usage of gene segments selected from the germline gene set; most sequences contained high levels of non-templated-nucleotide additions (N-additions) that could contribute to junctional diversity of B cell receptors. Finally, we report that a subset of monoclonal IgM antibodies against pyrP/DNA established from the apoE−/− mice also contained abundant N-additions. These results suggest that the accumulation of pyrP due to apoE deficiency may influence clonal diversity in the pyrP-specific B cell repertoire. The discovery of these unique B-1a cells for pyrP/DNA provides a key link connecting covalent protein modification, lipoprotein metabolism, and innate immunity. 相似文献
992.
993.
The nature of the chiasma as a cytological parameter for analysing cross-over was reexamined quantitatively by an improved chiasma graph method. It was reconfirmed in Mus platythrix (n =13) that interstitial chiasmata at diakinesis are distributed randomly and almost uniformly along bivalents except for the centromere and telomere regions. The size of these chiasma blank regions was consistently 0.8% of the total length of haploid autosomes in all chromosomes. There was a minimum value of chiasma interference distance between two adjacent chiasmata, which was constantly 1.8% in all chromosomes. The chiasma frequency at diakinesis was 20.1+/-2. 0 by the conventional method including terminal chiasmata. However, the primed in situ labeling technique revealed that terminal chiasmata were mostly telomere-telomere associations. From these data and also from recent molecular data we concluded that the terminal chiasma is cytologically functional for ensuring the normal disjunction of bivalents at anaphase I, but genetically non-functional for shuffling genes. The chiasma frequency excluding terminal chiasmata was 14.6+/-1.8. Reexamination of the chiasma frequency of 106 animal species revealed that the chiasma frequency increased linearly in proportion to the haploid chromosome number in spite of remarkable difference in their genome size. The increase in chiasma frequency would be evolution-adaptive, because gene shuffling is expected to be accelerated in species with high chromosome numbers. 相似文献
994.
The Starch-Debranching Enzymes Isoamylase and Pullulanase Are Both Involved in Amylopectin Biosynthesis in Rice Endosperm 总被引:20,自引:1,他引:19
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Akiko Kubo Naoko Fujita Kyuya Harada Toshiaki Matsuda Hikaru Satoh Yasunori Nakamura 《Plant physiology》1999,121(2):399-410
The activities of the two types of starch debranching enzymes, isoamylase and pullulanase, were greatly reduced in endosperms of allelic sugary-1 mutants of rice (Oryza sativa), with the decrease more pronounced for isoamylase than for pullulanase. However, the decrease in isoamylase activity was not related to the magnitude of the sugary phenotype (the proportion of the phytoglycogen region of the endosperm), as observed with pullulanase. In the moderately mutated line EM-5, the pullulanase activity was markedly lower in the phytoglycogen region than in the starch region, and isoamylase activity was extremely low or completely lost in the whole endosperm tissue. These results suggest that both debranching enzymes are involved in amylopectin biosynthesis in rice endosperm. We presume that isoamylase plays a predominant role in amylopectin synthesis, but pullulanase is also essential or can compensate for the role of isoamylase in the construction of the amylopectin multiple-cluster structure. It is highly possible that isoamylase was modified in some sugary-1 mutants such as EM-273 and EM-5, since it was present in significant and trace amounts, respectively, in these mutants but was apparently inactive. The results show that the Sugary-1 gene encodes the isoamylase gene of the rice genome. 相似文献
995.
Y Takeuchi K Nishimura N Aoki T Adachi C Sato K Kitajima T Matsuda 《European journal of biochemistry》1999,260(3):736-742
996.
Two cytosolic cyclophilin genes of Arabidopsis thaliana differently regulated in temporal- and organ-specific expression. 总被引:2,自引:0,他引:2
T Saito K Tadakuma N Takahashi H Ashida K Tanaka M Kawamukai H Matsuda T Nakagawa 《Bioscience, biotechnology, and biochemistry》1999,63(4):632-637
We have previously isolated two closely related genes (ATCYP1 and ATCYP2) each encoding a cytosolic cyclophilin of Arabidopsis thaliana. Here we tested expression patterns of these two genes by Northern analysis and by histochemical analysis with transgenic plants carrying the promoter: beta-glucuronidase (GUS) fusion. The results showed that ATCYP1 is predominantly transcribed in vascular tissue and flowers, but ATCYP2 is at higher levels in younger leaves. The different expression patterns seemed to be conferred by the quite different promoter structures carrying various cis elements. Our finding suggests that the two cyclophilins have different roles in Arabidopsis thaliana cells. 相似文献
997.
Abstract The promoting effects on cell proliferation of the 105K glycoprotein (105Kgp), purified from sera of chickens to which a Marek's disease (MD) lymphoblastoid cell line, MDCC-MSB1-41C (MSB1-41C), had been transplanted, were examined using culture cells from various sources. The MSB1-41C line as well as the other chicken lymphoblastoid cell lines examined were sensitive to the 105Kgp. The growth-promoting effects of 105Kgp showed a biphasic pattern depending upon the amount of 105Kgp added into the culture medium.
These findings indicate that the 105Kgp may be a promoting factor for chicken growing cells, especially lymphoblastoid cell lines. 相似文献
These findings indicate that the 105Kgp may be a promoting factor for chicken growing cells, especially lymphoblastoid cell lines. 相似文献
998.
T Matsuda H Tonomura A Baba H Iwata 《The International journal of biochemistry》1991,23(10):1111-1114
1. Thiamine triphosphatase activity in particulate fraction, but not in soluble, of rat skeletal muscle was stimulated by several anions. 2. The stimulative effect of anions was dependent on pH of reaction medium and was reversible. 3. The activities of ATPase in rat muscle particulate preparation and thiamine triphosphatase in the brain were inhibited by the anions. 相似文献
999.
1000.
Takuya Tsumita Ryo Takeda Nako Maishi Yasuhiro Hida Michihito Sasaki Yasuko Orba Akihiko Sato Shinsuke Toba Wataru Ito Takahito Teshirogi Yuya Sakurai Tomohiro Iba Hisamichi Naito Hitoshi Ando Haruhisa Watanabe Amane Mizuno Toshiki Nakanishi Aya Matsuda Ren Zixiao Ji-Won Lee Tadahiro Iimura Hirofumi Sawa Kyoko Hida 《Aging cell》2024,23(2):e14050