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51.
Solubilization and reconstitution of ca pump from corn leaf plasma membrane 总被引:1,自引:0,他引:1 下载免费PDF全文
The Ca2+ transport system of corn (Zea mays) leaf plasma membrane is composed of Ca2+ pump and Ca2+/H+ antiporter driven by H+ gradient imposed by a H+ pump (M Kasai, S Muto [1990] J Membr Biol 114: 133-142). It is necessary for characterization of these Ca2+ transporters to establish the procedure for their solubilization, isolation, and reconstitution into liposomes. We attempted to solubilize and reconstitute the Ca2+ pump in the present study. A nonionic detergent octaethyleneglycol monododecyl ether (C12E8) was the most effective detergent for a series of extraction and functional reconstitution of the Ca2+ pump among seven detergents examined. This was judged from activities of ATP-dependent 45Ca2+ uptake into liposomes reconstituted with the respective detergent-extract of the plasma membrane by the detergent dilution method. C12E8-extract of the plasma membrane was subjected to high performance liquid chromatography using a DEAE anion exchange column. Ca2+-ATPase was separated from VO43−-sensitive Mg2+-ATPase. These ATPases were separately reconstituted into liposomes, and their ATP-dependent Ca2+ uptake was measured. The liposomes reconstituted with the Ca2+-ATPase, but not with the VO43−-sensitive Mg2+-ATPase, showed ATP-dependent Ca2+ uptake. Nigericin-induced pH gradient (acid inside) caused only a little Ca2+ uptake into liposomes reconstituted with the Ca2+-ATPase, suggesting that the Ca2+/H+ antiporter was not present in the preparation. These results indicate that the Ca2+-ATPase actually functions as Ca2+ pump in the corn leaf plasma membrane. 相似文献
52.
Yoshiyuki Manabe Satomi Kasahara Yohei Takakura Xiaoxiao Yang Shinji Takamatsu Yoshihiro Kamada Eiji Miyoshi Daisuke Yoshidome Koichi Fukase 《Bioorganic & medicinal chemistry》2017,25(11):2844-2850
We developed α1,6-fucosyltransferase (FUT8) inhibitors through a diversity-oriented synthesis. The coupling reaction between the fucose unit containing alkyne and the guanine unit containing sulfonyl azide under various conditions afforded a series of Guanosine 5′-diphospho-β-l-fucose (GDP-fucose) analogs. The synthesized compounds displayed FUT8 inhibition activity. A docking study revealed that the binding mode of the inhibitor synthesized with FUT8 was similar to that of GDP-fucose. 相似文献
53.
Double overexpression of DREB and PIF transcription factors improves drought stress tolerance and cell elongation in transgenic plants 下载免费PDF全文
54.
Abscisic acid (ABA) is not a plant-specific compound but one found in organisms across kingdoms from bacteria to animals,
suggesting that it is a ubiquitous and versatile substance that can modulate physiological functions of various organisms.
Recent studies have shown that plants developed an elegant system for ABA sensing and early signal transduction mechanisms
to modulate responses to environmental stresses for survival in terrestrial conditions. ABA-induced increase in stress tolerance
has been reported not only in vascular plants but also in non-vascular bryophytes. Since bryophytes are the key group of organisms
in the context of plant evolution, clarification of their ABA-dependent processes is important for understanding evolutionary
adaptation of land plants. Molecular approaches using Physcomitrella patens have revealed that ABA plays a role in dehydration stress tolerance in mosses, which comprise a major group of bryophytes.
Furthermore, we recently reported that signaling machinery for ABA responses is also conserved in liverworts, representing
the most basal members of extant land plant lineage. Conservation of the mechanism for ABA sensing and responses in angiosperms
and basal land plants suggests that acquisition of this mechanism for stress tolerance in vegetative tissues was one of the
critical evolutionary events for adaptation to the land. This review describes the role of ABA in basal land plants as well
as non-land plant organisms and further elaborates on recent progress in molecular studies of model bryophytes by comparative
and functional genomic approaches. 相似文献
55.
56.
The evolution of between‐species reproductive interference capability under different within‐species mating regimes 下载免费PDF全文
Daisuke Kyogoku Teiji Sota 《Evolution; international journal of organic evolution》2017,71(11):2721-2727
Sexual selection sometimes favors male traits that benefit their bearers, but harm their mates. The harmful effects of male traits may also extend to females of other species via heterospecific mating interactions. This could affect the coexistence of closely related species during secondary contact. We examined the evolution of the interspecific interfering capability of a beetle (Callosobruchus chinensis) with a congener (C. maculatus) using C. chinensis males reared under conditions of monogamy and polygamy for 17 generations. After experimental evolution, C. chinensis males reared under polygamous conditions imposed greater impacts on offspring production by C. maculatus females than did C. chinensis males reared under monogamous conditions. However, the mechanism by which differential mating regimes altered the effect of C. chinensis males on C. maculatus females was unclear, because we did not find evidence for the expected genital evolution in C. chinensis, despite their body size divergence. Our findings suggest that traits that originally evolved through sexual selection in two allopatric species could influence the coexistence of these species or the likelihood of reinforcement during secondary contact. 相似文献
57.
Masuda K Tamagake K Okuda Y Torigoe F Tsuzuki D Isobe T Hichiya H Hanioka N Yamamoto S Narimatsu S 《Chirality》2005,17(1):37-43
The functional roles of phenylalanine at position 120 in drug oxidation by cytochrome P450 2D6 (CYP2D6) were examined using a yeast cell expression system and bufuralol (BF) enantiomers as a chiral substrate. Two mutated cDNAs, one encoding a CYP2D6 mutant having alanine instead of Phe-120 (F120A) and another encoding a mutant having alanine instead of Glu-222 (E222A), were prepared by site-directed mutagenesis and transformed into yeast cells via pGYRI vectors. The enantiomeric BF 1'-hydroxylase activities of the mutants were compared with those of the wild type. When enantiomeric BF 1'-hydroxylase activities at a substrate concentration of 100 microM were compared, the CYP2D6 wild type showed substrate enantioselectivity of (R-BF > S-BF) and the F120A mutant exhibited substrate enantioselectivity of (R-BF < or = S-BF), whereas the product diastereoselectivity of (1'R-OH-BF < 1'-S-OH-BF) was similar between the wild type and the mutant. The activities of the other mutant (E222A) were much lower than those of the wild type and the F120A mutant, while its substrate enantioselectivity and product diastereoselectivity were the same as those of the wild type. The kinetics demonstrated that apparent K(m) values were similar among the recombinant enzymes, and V(max) values clearly reflected the selectivity described above. These results indicate that Phe-120 has a key role in the enantioselective BF 1'-hydroxylation by CYP2D6. 相似文献
58.
Minyoung Jung Maria Mody Daisuke N. Saito Akemi Tomoda Hidehiko Okazawa Yuji Wada Hirotaka Kosaka 《PloS one》2015,10(11)
Autism spectrum traits exist on a continuum and are more common in males than in females, but the basis for this sex difference is unclear. To this end, the present study draws on the extreme male brain theory, investigating the relationship between sex difference and the default mode network (DMN), both known to be associated with autism spectrum traits. Resting-state functional magnetic resonance imaging (MRI) was carried out in 42 females (mean age ± standard deviation, 22.4 ± 4.2 years) and 43 males (mean age ± standard deviation, 23.8 ± 3.9 years) with typical development. Using a combination of different analyses (viz., independent component analysis (ICA), fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and seed-based analyses), we examined sex differences in the DMN and the relationship to autism spectrum traits as measured by autism-spectrum quotient (AQ) scores. We found significant differences between female and male subjects in DMN brain regions, with seed-based analysis revealing a significant negative correlation between default-mode resting state functional connectivity of the anterior medial prefrontal cortex seed (aMPFC) and AQ scores in males. However, there were no relationships between DMN sex differences and autism spectrum traits in females. Our findings may provide important insight into the skewed balance of functional connectivity in males compared to females that could serve as a potential biomarker of the degree of autism spectrum traits in line with the extreme male brain theory. 相似文献
59.
Kağan Eryürük Daisuke Suzuki Shin'ya Mizuno Tetsuji Akatsuka Takayuki Tsuchiya Suyin Yang 《Geomicrobiology journal》2016,33(8):690-698
The hydraulic conductivity of a paddy field (Anthraquic Dystrustept), a silty clay soil containing more than 29% (w/w) of gravel, in Nagoya University Farm was reduced by in situ treatment of subsurface soil using bentonite and biocalcification (microbial calcium carbonate precipitation) through the addition of CaCl2, urea, and corn steep liquor (CSL). The treatment decreased the hydraulic conductivity of the field from an average of 10?3 cm/s to a range of 10?5 to 10?7 cm/s during 69 days, with reducing the proportion of pores of subsurface soil larger than 75 µm in diameter. The biocalcification effect was observed at 10-cm thickness from the treated subsurface. Laboratory soil core experiments demonstrated that the decrease in the hydraulic conductivity was not attributed to the effect of bentonite but mainly to the effect of biocalcification. The addition of CSL enhanced the urease activity of soil required for biocalcification, even at 4°C, as indicated by a decrease in urease activation energy temperature sensitivity. These experimental results agreed with the gradual decrease in hydraulic conductivity observed in the field when the average daily temperature was 7°C (days 24–69). It was suggested that the biocalcification is a potential technique to reduce the hydraulic conductivity of paddy field. 相似文献
60.
Nakahara Y Watanabe M Fujita A Kanamori Y Tanaka D Iwata K Furuki T Sakurai M Kikawada T Okuda T 《Journal of insect physiology》2008,54(8):1220-1225
Strategies to combat desiccation are critical for organisms living in arid and semi-arid areas. Larvae of the Australian chironomid Paraborniella tonnoiri resist desiccation by reducing water loss. In contrast, larvae of the African species Polypedilum vanderplanki can withstand almost complete dehydration, referred to as anhydrobiosis. For successful anhydrobiosis, the dehydration rate of P. vanderplanki larvae has to be controlled. Here, we desiccated larvae by exposing them to different drying regimes, each progressing from high to low relative humidity, and examined survival after rehydration. In larvae of P. vanderplanki, reactions following desiccation can be categorized as follows: (I) no recovery at all (direct death), (II) dying by unrepairable damages after rehydration (delayed death), and (III) full recovery (successful anhydrobiosis). Initial conditions of desiccation severely affected survival following rehydration, i.e. P. vanderplanki preferred 100% relative humidity where body water content decreased slightly. In subsequent conditions, unfavorable dehydration rate, such as more than 0.7 mg water lost per day, resulted in markedly decreased survival rate of rehydrated larvae. Slow dehydration may be required for the synthesis and distribution of essential molecules for anhydrobiosis. Larvae desiccated at or above maximum tolerable rates sometimes showed temporary recovery but died soon after. 相似文献