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Shu-ichi Nakano Yuuki Uotani Yuichi Sato Hirohito Oka Masayuki Fujii Naoki Sugimoto 《Nucleic acids research》2013,41(18):8581-8590
DNA lesions produced by aromatic isocyanates have an extra bulky group on the nucleotide bases, with the capability of forming stacking interaction within a DNA helix. In this work, we investigated the conformation of the 2′-deoxyadenosine and 2′-deoxycytidine derivatives tethering a phenyl or naphthyl group, introduced in a DNA duplex. The chemical modification experiments using KMnO4 and 1-cyclohexyl-3 -(2-morpholinoethyl) carbodiimide metho-p-toluenesulfonate have shown that the 2′-deoxycytidine lesions form the base pair with guanine while the 2′-deoxyadenosine lesions have less ability of forming the base pair with thymine in solution. Nevertheless, the kinetic analysis shows that these DNA lesions are compatible with DNA ligase and DNA polymerase reactions, as much as natural DNA bases. We suggest that the adduct lesions have a capability of adopting dual conformations, depending on the difference in their interaction energies between stacking of the attached aromatic group and base pairing through hydrogen bonds. It is also presented that the attached aromatic groups change their orientation by interacting with the minor groove binding netropsin, distamycin and synthetic polyamide. The nucleotide derivatives would be useful for enhancing the phenotypic diversity of DNA molecules and for exploring new non-natural nucleotides. 相似文献
144.
Hiroshi Fukayama Chisato Masumoto Yojiro Taniguchi Akiko Baba-Kasai Yuuki Katoh Hiroshi Ohkawa 《Bioscience, biotechnology, and biochemistry》2013,77(3):402-409
To verify the presence of enolase related to the chloroplastic glycolysis in rice, database search was carried out and identified seven putative enolase genes in the rice genome. Among them, OsEno1 and OsEno3 encode long proteins with N-terminal extensions. GFP protein fusions of these N-terminal extensions were both targeted to plastids of onion epidermal cell. Promoter::GUS analysis showed that OsEno3 was highly expressed in young developing leaves, but its expression was drastically decreased during leaf development and greening. On the other hand, the expression of OsEno1 was low and detected in limited portions such as leaf sheath at the tiller base. Recombinant OsEno1 protein showed enolase activity with a pH optimum at pH 8.0, whereas OsEno3 did not exhibit detectable activity. Although it remains obscure if OsEno3 encodes a functional enolase in vivo, our results demonstrate that the entire glycolytic pathway does not operate in rice chloroplasts. 相似文献
145.
Maki Sato Dominika Kanikowska Junichi Sugenoya Yoko Inukai Yuuki Shimizu Naoki Nishimura Satoshi Iwase 《International journal of biometeorology》2011,55(2):229-234
Physiological functions are impaired in various organs in aged people, as manifest by, e.g., renal and cardiac dysfunction
and muscle atrophy. The elderly are also at increased risk of both hypothermia and hyperthermia in extreme temperatures. The
majority of those over 65 years old have elevated serum osmolality. Our hypothesis is that the elderly have suppressed osmolality
control in different seasons compared to the young. Eight healthy young men and six healthy older men participated in this
study. The experiments were performed during spring, summer, autumn and winter in Japan, with average atmospheric temperatures
of 15–20°C in spring, 25–30°C in summer, 15–23°C in autumn and 5–10°C in winter. Each subject immersed his lower legs in warm
water at 40°C for 30 min. Core (tympanic) temperature and sweat rate at chest were recorded continuously. Blood was taken
pre-immersion to measure the concentrations of antidiuretic hormone, serum osmolality, plasma renin activity, angiotensin
II, aldosterone, leptin, thyroid stimulating hormone, fT3 and fT4. The results suggested that the elderly have suppressed osmolality control compared to the young; osmolality was especially
elevated in winter compared to the summer in elderly subjects. Therefore, particularly in the elderly, balancing fluid by
drinking water should be encouraged to maintain euhydration status in winter. 相似文献
146.
Watanabe YY Sato K Watanuki Y Takahashi A Mitani Y Amano M Aoki K Narazaki T Iwata T Minamikawa S Miyazaki N 《The Journal of animal ecology》2011,80(1):57-68
1. Breath-hold divers are widely assumed to descend and ascend at the speed that minimizes energy expenditure per distance travelled (the cost of transport (COT)) to maximize foraging duration at depth. However, measuring COT with captive animals is difficult, and empirical support for this hypothesis is sparse. 2. We examined the scaling relationship of swim speed in free-ranging diving birds, mammals and turtles (37 species; mass range, 0·5-90,000 kg) with phylogenetically informed statistical methods and derived the theoretical prediction for the allometric exponent under the COT hypothesis by constructing a biomechanical model. 3. Swim speed significantly increased with mass, despite considerable variations around the scaling line. The allometric exponent (0·09) was statistically consistent with the theoretical prediction (0·05) of the COT hypothesis. 4. Our finding suggests a previously unrecognized advantage of size in divers: larger animals swim faster and thus could travel longer distance, search larger volume of water for prey and exploit a greater range of depths during a given dive duration. 5. Furthermore, as predicted from the model, endotherms (birds and mammals) swam faster than ectotherms (turtles) for their size, suggesting that metabolic power production limits swim speed. Among endotherms, birds swam faster than mammals, which cannot be explained by the model. Reynolds numbers of small birds (<2 kg) were close to the lower limit of turbulent flow (~ 3 × 10(5) ), and they swam fast possibly to avoid the increased drag associated with flow transition. 相似文献
147.
Each symbiotic Chlorella of the ciliate Paramecium bursaria is enclosed in a perialgal vacuole membrane derived from the host digestive vacuole membrane. Alga-free paramecia and symbiotic
algae can grow independently. Mixing them experimentally can cause reinfection. Earlier, we reported that the symbiotic algae
appear to push the host trichocysts aside to become fixed beneath the host cell cortex during the algal reinfection process.
Indirect immunofluorescence microscopy with a monoclonal antibody against the trichocysts demonstrates that the trichocysts
change their locality to form algal attachment sites and decrease their density beneath the host cell cortex through algal
reinfection. Transmission electron microscopy to detect acid phosphatase activity showed that some trichocysts near the host
cell cortex are digested by the host lysosomal fusion during algal reinfection. Removal of algae from the host cell using
cycloheximide recovers the trichocyst's arrangement and number near the host cell cortex. These results indicate that symbiotic
algae compete for their attachment sites with preexisting trichocysts and that the algae have the ability to ensure algal
attachment sites beneath the host cell cortex. 相似文献
148.
In higher plants, many extracellular proteins are involved in developmental processes, including cell-cell signaling and cell wall construction. Xylogen is an extracellular arabinogalactan protein (AGP) isolated from Zinnia elegans xylogenic culture medium, which promotes xylem cell differentiation. Xylogen has a unique structure, containing a non-specific lipid transfer protein (nsLTP) domain and AGP domains. We searched for xylogen-type genes in the genomes of land plants, including Arabidopsis thaliana, to further our knowledge of xylogen-type genes as functional extracellular proteins in plants. We found that many xylogen-type genes, including 13 Arabidopsis genes, comprise a gene family in land plants, including Populus trichocarpa, Vitis vinifera, Lotus japonicus, Oryza sativa, Selaginella moellendorffii and Physcomitrella patens. The genes shared an N-terminal signal peptide sequence, a distinct nsLTP domain, one or more AGP domains and a glycosylphosphatidylinositol (GPI)-anchored sequence. We analyzed transgenic plants harboring promoter::GUS (β-glucuronidase) constructs to test expression of the 13 Arabidopsis xylogen-type genes, and detected a diversity of gene family members with related expression patterns. AtXYP2 was the best candidate as the Arabidopsis counterpart of the Zinnia xylogen gene. We observed two distinct expression patterns for several genes, with some anther specific and others preferentially expressed in the endodermis/pericycle. We conclude that xylogen-type genes, which may have diverse functions, form a novel chimeric AGP gene family with a distinct nsLTP domain. 相似文献
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