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941.
Nishida Y Adachi K Kasai H Shizuri Y Shindo K Sawabe A Komemushi S Miki W Misawa N 《Applied and environmental microbiology》2005,71(8):4286-4296
A carotenoid biosynthesis gene cluster mediating the production of 2-hydroxyastaxanthin was isolated from the marine bacterium Brevundimonas sp. strain SD212 by using a common crtI sequence as the probe DNA. A sequence analysis revealed this cluster to contain 12 open reading frames (ORFs), including the 7 known genes, crtW, crtY, crtI, crtB, crtE, idi, and crtZ. The individual ORFs were functionally analyzed by complementation studies using Escherichia coli that accumulated various carotenoid precursors due to the presence of other bacterial crt genes. In addition to functionally identifying the known crt genes, we found that one (ORF11, named crtG) coded for a novel enzyme, carotenoid 2,2'-beta-hydroxylase, which showed intriguingly partial homology with animal sterol-C5-desaturase. When this crtG gene was introduced into E. coli accumulating zeaxanthin and canthaxanthin, the resulting transformants produced their 2-hydroxylated and 2,2'-dihydroxylated products which were structurally novel or rare xanthophylls, as determined by their nuclear magnetic resonance and high-performance liquid chromatography/photodiode array detector/atmospheric pressure chemical ionization mass spectrometry spectral data. The new carotenoid produced was suggested to have a strong inhibitory effect on lipid peroxidation. 相似文献
942.
Masuda K Kubagawa H Ikawa T Chen CC Kakugawa K Hattori M Kageyama R Cooper MD Minato N Katsura Y Kawamoto H 《The EMBO journal》2005,24(23):4052-4060
T cells are produced in the thymus from progenitors of extrathymic origin. As no specific markers are available, the developmental pathway of progenitors preceding thymic colonization remains unclear. Here we show that progenitors in murine fetal liver and blood, which are capable of giving rise to T cells, NK cells and dendritic cells, but not B cells, can be isolated by their surface expression of paired immunoglobulin-like receptors (PIR). PIR expression is maintained until the earliest intrathymic stage, then downregulated before the onset of CD25 expression. Unlike intrathymic progenitors, generation of prethymic PIR(+) progenitors does not require Hes1-mediated Notch signaling. These findings disclose a prethymic stage of T-cell development programmed for immigration of the thymus, which is genetically separable from intrathymic stages. 相似文献
943.
Ishihara K Nakata K Yamagishi N Iwasaki S Kiriike N Hatayama T 《Molecular and cellular biochemistry》2005,276(1-2):21-29
Although neurochemical changes have been reported in the brain in animal models of binge eating, biochemical changes of specific proteins in the brain are unknown. Our aim was to elucidate brain proteins altered in rats during enhanced rebound hyperphargia. Rats were deprived of food for 22 h/day for 6 days, then allowed free access to food for 24 h in normal cages (rebound hyperphargia) or in space-restricted cages (enhanced rebound hyperphargia). Proteins extracted from the rat brain were separated by two-dimensional gel electrophoresis, and compared with those from control rats freely fed for 7 days in normal cages. Proteins expressed differently from controls were identified by N-terminal amino acid sequencing and mass fingerprinting using a MALDI-TOF mass spectrometer. Among proteins in the corpus striatum, frontal lobe, hippocampus and thalamus/hypothalamus, ubiquitin C-terminal hydrolase L1 and peroxiredoxin 2 decreased in the hippocampus and phosphatidylethanolamine-binding protein increased in the thalamus/hypothalamus of rats with the enhanced rebound hyperphargia induced by space-restriction. In this study, we first demonstrated that three brain proteins changed in rats during enhanced rebound hyperphagia. These proteins might have pathophysiologic relevance to binge eating. (Mol Cell Biochem 276: 21–29, 2005) 相似文献
944.
Choi SK Nishida Y Matsuda S Adachi K Kasai H Peng X Komemushi S Miki W Misawa N 《Marine biotechnology (New York, N.Y.)》2005,7(5):515-522
A complementation analysis was performed in Escherichia coli to evaluate the efficiency of β-carotene ketolases (CrtW) from the marine bacteria Brevundimonas sp. SD212, Paracoccus sp. PC1 (Alcaligenes PC-1), and Paracoccus sp. N81106 (Agrobacterium aurantiacum), for astaxanthin production. Each crtW gene was expressed in Escherichia coli synthesizing zeaxanthin due to the presence of plasmid pACCAR25ΔcrtX. Carotenoids that accumulated in the resulting E. coli transformants were examined by chromatographic and spectroscopic analyses. The transformant carrying the Paracoccus sp. PC1 or N81106 crtW gene accumulated high levels of adonixanthin, which is the final astaxanthin precursor for CrtW, and astaxanthin, while the
E. coli transformant with crtW from Brevundimonas sp. SD212 did not accumulate any adonixanthin and produced a high level of astaxanthin. These results show efficient conversion
by CrtW of Brevundimonas sp. SD212 from adonixanthin to astaxanthin, which is a new-found characteristic of a bacterial CrtW enzyme. The phylogenetic
positions between CrtW of the two genera, Brevundimonas and Paracoccus, are distant, although they fall into α-Proteobacteria. 相似文献
945.
New analogs of desmosdumotin C (1), in which other aromatic rings replaced the terminal phenyl group and the A-ring was modified, were synthesized. Compounds 2-9, 13, and 16 were evaluated in vitro against human tumor cell replication. The 4-bromophenyl analog (2) showed potent cytotoxic activity in four different tumor cell lines. 相似文献
946.
Synthesis of potent and selective inhibitors of Candida albicans N-myristoyltransferase based on the benzothiazole structure 总被引:1,自引:0,他引:1
Yamazaki K Kaneko Y Suwa K Ebara S Nakazawa K Yasuno K 《Bioorganic & medicinal chemistry》2005,13(7):2509-2522
Two parallel synthetic methods using solid-supported reagents were established to examine the rapid optimization of weak hit compound 1. Several compounds showed high potency in the low nanomolar range against N-myristoyltransferase. The structure-activity relationship (SAR) and antifungal activities of a series of novel 2-aminobenzothiazole N-myristoyltransferase inhibitors are presented. 相似文献
947.
948.
Hoshina Y Ikegami S Okuyama A Fukui H Inoguchi K Maruyama T Fujimoto K Matsumura Y Aoyama A Harada T Tanaka H Nakamura T 《Bioorganic & medicinal chemistry letters》2005,15(1):217-220
The discovery and SAR of 2,3-diphenylpropionic acid derivatives as highly potent VLA-4 antagonists are described. One representative compound, 9cc has inhibited intercellular adhesion by a VCAM-1/VLA-4 interaction with an IC(50) of 1.7 nM, and has good pharmacokinetics and oral bioavailability. 相似文献
949.
Kawakami Y Tsurugasaki W Nakamura S Osada K 《The Journal of nutritional biochemistry》2005,16(4):205-212
The effects of dietary soy isoflavones aglycone and glucoside on lipid metabolism were compared in male Sprague-Dawley rats (4 weeks old) given purified diets containing 0.3% cholesterol. The rats were fed a diet supplemented with either isoflavone aglycone-rich powder (IF-A group) or isoflavone glucoside-rich powder (IF-G group) or isoflavone-free diet (control group) for 40 days. The additional level of isoflavone aglycone moiety in the diet was prepared to the same level (approximately 0.096 g/100 g: approximately 0.1% in diet). The activity of hepatic cholesterol 7alpha-hydroxylase tended to be slightly higher in the rats fed isoflavones than in those fed the isoflavone-free diet. On the other hand, the activity of hepatic Delta6 desaturase in the IF-A group was lower than that of the control group. Reflecting this effect, the Delta6 desaturation indices [(20:3n-6+20:4n-6)/18:2n-6] in liver phospholipids of the IF-A group were lower than those in the control group. Liver and serum total cholesterol levels and liver TG level were also reduced by consumption of isoflavone aglycone. Moreover, serum TG level was lowered by consumption of both isoflavones aglycone and glucoside. The level of serum total isoflavones in the IF-A group was significantly higher than that in the IF-G group. Therefore, we speculate that the absorption speed of isoflavone aglycones might be faster than that of isoflavone glucosides in rats. This study suggests that dietary soy isoflavones, particularly their aglycone form, may exert a beneficial effect on lipid metabolism in rats fed cholesterol. 相似文献
950.
Suzuki H Motohara M Miyake A Ibuki K Fukazawa Y Inaba K Masuda K Minato N Kawamoto H Hayami M Miura T 《Microbiology and immunology》2005,49(7):667-679
We intrarectally infected newborn macaques with a pathogenic simian/human immunodeficiency virus (SHIV) that induced rapid and profound CD4 (+) T cell depletion, and examined the early effects of this SHIV on the thymus. After intrarectal infection, viral loads were much higher in the thymus than in other lymphoid tissues in newborns. In contrast, no clear difference was seen in the viral loads of different tissues in adults. Histological and immunohistochemical observations showed severe thymic involution. Depletion of CD4 (+) thymocytes began in the medulla at 2 weeks post infection and spread over the whole thymus. After in vivo infection, the CD2 (+) subpopulation, which represents a relatively later stage of T cell progenitors, was selectively reduced and development of thymocytes from CD3 (-) CD4 (-) CD8 (-) cells to CD4 (+) CD8 (+) cells was impaired. These results suggest that profound and irreversible loss of CD4 (+) cells that are observed in the peripheral blood of SHIV-infected monkeys are due to destruction of the thymus and impaired thymopoiesis as a result of SHIV infection in the thymus. 相似文献