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51.
George Imataka Osamu Sakamoto Hideo Yamanouchi Shigemi Yoshihara Yuki Omura-Hasegawa Go Tajima Osamu Arisaka 《Cell biochemistry and biophysics》2013,67(1):185-187
We report herein a 1.5-year-old girl with methylmalonic acidemia (MMA) in whom two missense mutations were found: a novel I739T mutation located in exon 13 and the L494X mutation in exon 8. The results of organic acid test showed a pronounced increase in methylmalonate excretion with increased methylcitrate and 3-OH-propionate excretion, leading to a diagnosis of MMA, and Vitamin B12 administration was started. Analysis of the mut gene confirmed a T-to-A substitution at nucleotide position 1481 in exon 8 and a T-to-C substitution at nucleotide position 2216 in exon 13, leading to the amino acid isoleucine at position 739 being changed to threonine, resulting in c.2216T > C (p.I739T). The patient has now been on high-dose oral administration of Vitamin B12 and carnitine therapy (900 mg of levocarnitine chloride) for 5 years without experiencing further attacks, and her cognitive and motor development is normal. Further tests on residual enzyme activity, as well as experience with more cases, may shed light on the relationship between gene mutations and phenotypes in MMA. 相似文献
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Sun Hee Choi Yuka Hagiwara-Komoda Kenji S. Nakahara Go Atsumi Ryoko Shimada Yusuke Hisa Satoshi Naito Ichiro Uyeda 《Journal of virology》2013,87(13):7326-7337
In pea carrying cyv1, a recessive gene for resistance to Clover yellow vein virus (ClYVV), ClYVV isolate Cl-no30 was restricted to the initially infected cells, whereas isolate 90-1 Br2 overcame this resistance. We mapped the region responsible for breaking of cyv1-mediated resistance by examining infection of cyv1 pea with chimeric viruses constructed from parts of Cl-no30 and 90-1 Br2. The breaking of resistance was attributed to the P3 cistron, which is known to produce two proteins: P3, from the main open reading frame (ORF), and P3N-PIPO, which has the N-terminal part of P3 fused to amino acids encoded by a small open reading frame (ORF) called PIPO in the +2 reading frame. We introduced point mutations that were synonymous with respect to the P3 protein but nonsynonymous with respect to the P3N-PIPO protein, and vice versa, into the chimeric viruses. Infection of plants with these mutant viruses revealed that both P3 and P3N-PIPO were involved in overcoming cyv1-mediated resistance. Moreover, P3N-PIPO quantitatively affected the virulence of Cl-no30 in cyv1 pea. Additional expression in trans of the P3N-PIPO derived from Cl-no30, using White clover mosaic virus as a vector, enabled Cl-no30 to move to systemic leaves in cyv1 pea. Susceptible pea plants infected with chimeric ClYVV possessing the P3 cistron of 90-1 Br2, and which were therefore virulent toward cyv1 pea, accumulated more P3N-PIPO than did those infected with Cl-no30, suggesting that the higher level of P3N-PIPO in infected cells contributed to the breaking of resistance by 90-1 Br2. This is the first report showing that P3N-PIPO is a virulence determinant in plants resistant to a potyvirus. 相似文献
56.
Yong-Hak Kim Woo-Seok Song Hayoung Go Chang-Jun Cha Cheolju Lee Myeong-Hee Yu Peter C. K. Lau Kangseok Lee 《Journal of bacteriology》2013,195(2):180-192
2-Nitrobenzoate 2-nitroreductase (NbaA) of Pseudomonas fluorescens strain KU-7 is a unique enzyme, transforming 2-nitrobenzoic acid (2-NBA) and 2,4-dinitrobenzoic acid (2,4-DNBA) to the 2-hydroxylamine compounds. Sequence comparison reveals that NbaA contains a conserved cysteine residue at position 141 and two variable regions at amino acids 65 to 74 and 193 to 216. The truncated mutant Δ65-74 exhibited markedly reduced activity toward 2,4-DNBA, but its 2-NBA reduction activity was unaffected; however, both activities were abolished in the Δ193-216 mutant, suggesting that these regions are necessary for the catalysis and specificity of NbaA. NbaA showed different lag times for the reduction of 2-NBA and 2,4-DNBA with NADPH, and the reduction of 2,4-DNBA, but not 2-NBA, failed in the presence of 1 mM dithiothreitol or under anaerobic conditions, indicating oxidative modification of the enzyme for 2,4-DNBA. The enzyme was irreversibly inhibited by 5,5′-dithio-bis-(2-nitrobenzoic acid) and ZnCl2, which bind to reactive thiol/thiolate groups, and was eventually inactivated during the formation of higher-order oligomers at high pH, high temperature, or in the presence of H2O2. SDS-PAGE and mass spectrometry revealed the formation of intermolecular disulfide bonds by involvement of the two cysteines at positions 141 and 194. Site-directed mutagenesis indicated that the cysteines at positions 39, 103, 141, and 194 played a role in changing the enzyme activity and specificity toward 2-NBA and 2,4-DNBA. This study suggests that oxidative modifications of NbaA are responsible for the differential specificity for the two substrates and further enzyme inactivation through the formation of disulfide bonds under oxidizing conditions. 相似文献
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Hossam El-Sheikh Ali Go Kitahara Kazumi Nibe Ryoji Yamaguchi Yoichiro Horii Samy Zaabel Takeshi Osawa 《Theriogenology》2013
Granulosa-theca cell tumors (GTCTs) are the most frequently reported ovarian tumors in cattle. Clinically, GTCTs could be confused with other ovarian abnormalities; therefore, the only definitive diagnosis for such tumors is histopathology of a biopsy from the affected ovary. However, this is an invasive technique and unsuitable for farm conditions. As a result, the key aim of this study was to evaluate the diagnostic value of anti-Müllerian hormone (AMH), a glycoprotein hormone that is synthesized exclusively by ovarian granulosa cells, as a sensitive noninvasive biomarker for diagnosing GTCTs in cattle. To achieve this aim, we conducted two experiments. In experiment 1, four clinically healthy Japanese Black cows had blood samples taken daily over one estrous cycle to characterize their AMH profiles throughout the estrous cycle. Additionally, single blood samples were collected from 21 cyclic cows to clarify the physiological range of AMH. In experiment 2, cows with histologically confirmed GTCT (GTCT group, n = 9) and cows affected with cystic ovarian disease (COD group, n = 8) had one blood sample taken before extraction of the tumorous ovary or therapeutic treatment for the COD. Blood samples (n = 105) from cyclic cows (n = 25) in experiment 1 were assigned as a physiologically cyclic group (PC group). Plasma AMH, immunoreactive inhibin (ir-INH), estradiol-17β (E2), testosterone (T), and progesterone (P4) concentrations were assayed in all samples. In experiment 1, the mean plasma AMH concentration was 0.09 ± 0.003 ng/mL and did not show substantial fluctuation throughout the estrous cycle. In experiment 2, plasma AMH, ir-INH, and E2 concentrations were significantly elevated in the GTCT group in comparison with the PC group; among these parameters, only the AMH concentrations were significantly higher in the GTCT group than in the COD group. The area under the receiver operating characteristic curve of AMH for diagnosis of GTCT was 0.99 and was significantly higher than that of ir-INH (P < 0.001) and E2 (P < 0.01). Moreover, the AMH at a cutoff point of ≥0.36 ng/mL had the highest diagnostic accuracy (99.2%), sensitivity (100%), and specificity (99.1%) compared with the other tested parameters. In conclusion, plasma AMH concentration is probably a more reliable and sensitive biomarker for bovine GTCTs than the concentrations of ir-INH or ovarian steroids. 相似文献
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Multiple data are available on the self-assembly of mixtures of bilayer-forming amphiphiles, particularly phospholipids and micelle-forming amphiphiles, commonly denoted detergents. The structure of such mixed assemblies has been thoroughly investigated, described in phase diagrams, and theoretically rationalized in terms of the balance between the large spontaneous curvature of the curvophilic detergent and the curvophobic phospholipids. In this critical review, we discuss the mechanism of this process and try to explain the actual mechanism involved in solubilization. Interestingly, membrane solubilization by some detergents is relatively slow and the common attribute of these detergents is that their trans-bilayer movement, commonly denoted flip-flop, is very slow. Only detergents that can flip into the inner monolayer cause relatively rapid solubilization of detergent-saturated bilayers. This occurs via the following sequence of events: 1), relatively rapid penetration of detergent monomers into the outer monolayer; 2), trans-membrane equilibration of detergent monomers between the two monolayers; 3), saturation of the bilayer by detergents and consequent permeabilization of the membrane; and 4), transition of the whole bilayer to thread-like mixed micelles. When the detergent cannot flip to the inner monolayer, the outer monolayer becomes unstable due to mass imbalance between the monolayers and inclusion of the curvophilic detergent molecules in a flat surface. Consequently, the outer monolayer forms mixed micellar structures within the outer monolayer. Shedding of these micelles into the aqueous solution results in partial solubilization. The consequent leakage of detergent into the liposome results in trans-membrane equilibration of detergent and subsequent micellization through the rapid bilayer-saturation mechanism. 相似文献
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