http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : N.Sasaki (검색결과 23 건)
- 무료
- 기관 내 무료
- 유료
-
Coupling of Lever Arm Swing and Biased Brownian Motion in Actomyosin
Nie, Qing-Miao,Togashi, Akio,Sasaki, Takeshi N.,Takano, Mitsunori,Sasai, Masaki,Terada, Tomoki P. Public Library of Science 2014 PLoS computational biology Vol.10 No.4
<▼1><P>An important unresolved problem associated with actomyosin motors is the role of Brownian motion in the process of force generation. On the basis of structural observations of myosins and actins, the widely held lever-arm hypothesis has been proposed, in which proteins are assumed to show sequential structural changes among observed and hypothesized structures to exert mechanical force. An alternative hypothesis, the Brownian motion hypothesis, has been supported by single-molecule experiments and emphasizes more on the roles of fluctuating protein movement. In this study, we address the long-standing controversy between the lever-arm hypothesis and the Brownian motion hypothesis through <I>in silico</I> observations of an actomyosin system. We study a system composed of myosin II and actin filament by calculating free-energy landscapes of actin-myosin interactions using the molecular dynamics method and by simulating transitions among dynamically changing free-energy landscapes using the Monte Carlo method. The results obtained by this combined multi-scale calculation show that myosin with inorganic phosphate (P<SUB>i</SUB>) and ADP weakly binds to actin and that after releasing P<SUB>i</SUB> and ADP, myosin moves along the actin filament toward the strong-binding site by exhibiting the biased Brownian motion, a behavior consistent with the observed single-molecular behavior of myosin. Conformational flexibility of loops at the actin-interface of myosin and the N-terminus of actin subunit is necessary for the distinct bias in the Brownian motion. Both the 5.5–11 nm displacement due to the biased Brownian motion and the 3–5 nm displacement due to lever-arm swing contribute to the net displacement of myosin. The calculated results further suggest that the recovery stroke of the lever arm plays an important role in enhancing the displacement of myosin through multiple cycles of ATP hydrolysis, suggesting a unified movement mechanism for various members of the myosin family.</P></▼1><▼2><P><B>Author Summary</B></P><P>Myosin II is a molecular motor that is fueled by ATP hydrolysis and generates mechanical force by interacting with actin filament. Comparison among various myosin structures obtained by X-ray and electron microscope analyses has led to the hypothesis that structural change of myosin in ATP hydrolysis cycle is the driving mechanism of force generation. However, single-molecule experiments have suggested an alternative mechanism in which myosin moves stochastically in a biased direction along actin filament. Computer simulation serves as a platform for assessing these hypotheses by revealing the prominent features of the dynamically changing landscape of actin-myosin interaction. The calculated results show that myosin binds to actin at different locations of actin filament in the weak- and strong-binding states and that the free energy has a global gradient from the weak-binding site to the strong-binding site. Myosin relaxing into the strong-binding state therefore necessarily shows the biased Brownian motion toward the strong-binding site. Lever-arm swing is induced during this relaxation process; therefore, lever-arm swing and the biased Brownian motion are coupled to contribute to the net displacement of myosin. This coupling should affect the dynamical behaviors of muscle and cardiac systems.</P></▼2>
-
Sasaki, O.,Yamamoto, N.,Togashi, K.,Minezawa, M. Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.12
The aim of this study was to identify useful secondary traits for estimating genetic ability of milk production traits. We investigated the value of using plasma metabolites concentrations. Two hundred and nineteen cattle out of 271 had only milk production traits records (G1), 33 had only metabolites records (G2), and 19 had both milk production traits and metabolites records (G3). Fifty two calves with metabolites records (G2 and G3) were born from 1992 to 1997. Forty three calves (29 females, 14 males) were used from 10 to 90 d of age and the others (3 females, 6 males) from 10 to 60 d of age. A total of 566 records of milk yield, fat yield and protein yield for 240 to 305 d on 238 heads (G1 and G2) were collected The collected blood samples were divided into three age groups: AG1, 10 to 30 d; AG2, 40 to 60 d; and AG3, 70 to 90 d. Heritabilities of milk yield, fat yield and protein yield were $0.45{\pm}0.04$, $0.50{\pm}0.04$ and $0.38{\pm}0.04$, respectively. Heritability of plasma glucose concentration at AG1 was $0.45{\pm}0.08$. Genetic correlations between plasma glucose concentration and milk yield, fat yield and protein yield were -$0.35{\pm}0.28$, $0.64{\pm}0.24$ and $0.36{\pm}0.35$, respectively. When the plasma glucose concentration at AG1 was used to estimate genetic ability of these milk production traits, reliability of milk yield of animals without milk record increased 8.2%, fat yield increased 24.2% and protein yield increased 9.5%. Heritability of plasma total cholesterol concentration at AG3 was $0.83{\pm}0.04$. Genetic correlation between plasma total cholesterol concentration and milk yield, fat yield and protein yield were $0.58{\pm}0.21$, $0.42{\pm}0.20$ and $0.45{\pm}0.22$, respectively. When the plasma total cholesterol concentration at AG3 was using to estimate genetic ability of these milk production traits, reliability of milk yield of animals without milk record increased 19.0%, fat yield increased 9.6%, and protein yield increased 13.5%. The annual genetic gain is in proportion to the reliability of selection. These results show that the plasma metabolite concentrations would be useful for improvement of genetic ability for milk production traits in the genetic improvement in herd of cows, where half of the animals selected are from a herd without its own milk record.
-
-
N. Sinsamutpadung,E. Sasaki 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.3
This study aims to investigate the eff ects of strain rate on the low-cycle fatigue strength of steel welded joints. Load-carrying cruciform joints with diff erent material mismatch ratios were fabricated in order to observe the eff ects of material mismatching. A series of displacements that generate low-cycle fatigue damage were applied to the specimens. The experiment was conducted by fast cyclic loading and displacement control, using feedback from a displacement transducer. The feedback control algorithm was found to be critical. Thus, a non-linear feedback control algorithm, i.e., PID control, was implemented in the testing machine. An experimental setup capable of fast cyclic loading was developed. Fatigue life based on the load drop curve indicated that higher strain rates caused lower fatigue life. Failure behavior regarding the strain rate eff ects of steel welded joints was observed.
-
Effects of Age, Environments and Sex on Plasma Metabolite Levels in Young Holstein Calves
Sasaki, O.,Yamamoto, N.,Togashi, K.,Minezawa, M. Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.5
Thirty Holstein calves were used to determine effects of age, environment and sex on blood metabolite concentrations during 1 to 90 d of age. Calves were weaned at 75 d of age. Environmental effects are grouped by the difference in month at birth and site of feeding. Blood samples were obtained every 2 or 3 d. The mean metabolite concentration every 3 d was used for the statistical analysis. Dairy bodyweight gain was not affected by environmental group and sex effect. Concentrations of plasma glucose, nonesterified fatty acids (NEFA), triglyceride, total cholesterol and total ketone changed with growth. These developmental changes in metabolite levels would be caused by ruminal maturation with increment of grain intake. Levels of plasma urea nitrogen, glucose, NEFA, triglyceride and total cholesterol drastically changed during a few weeks after birth, indicating that the physiological state in calves greatly changed during that time. Effects of the environmental group and sex were significant in almost all metabolites. Temperature influenced plasma metabolite concentrations. The plasma metabolite concentrations were affected more intensely by heat stress in the infant period than in the neonatal period.
-
Contamination and Bioconcentration of Perfluorinated Compounds in Main River Ecosystems of Korea
N. H. Lam,C.R. Cho,M.S. Chang,B.C. Lee,P.J. Kim,K. Sasaki,H.S. Cho 한국해양환경·에너지학회 2012 한국해양환경공학회 학술대회논문집 Vol.2012 No.11
Water, sediment, plankton, blood and liver of crucian carp (Carassius carassius) and mandarin fish (Siniperca cherzeri) samples from 5 freshwater ecosystems in 3 major rivers of Korea including Nam Han River, Nakdong River and Yeongsan River were collected together with medaka fish (Oryzias latipes) and water in their 5 natural habitats. The samples were analyzed to determine the occurrence and contamination level of perfluorinated compounds (PFCs). The mean total concentration of detected PFCs was in the ascending order of water, sediment, plankton, crucian carp and mandarin fish. Longchain PFCs (≥C8) was widely detected and occupied 99.32% of total PFCs concentration. Perfluorooctane sulfonate (PFOS) was the dominant PFC in most of the ecosystem components with a maximum concentration in water of 6.25 ng/L and in fish of 273 ng/g wet wt. The results also demonstrated that concentration of PFOS and total PFCs in blood of crucian carp and mandarin fish were higher than those in their liver. PFOS concentrations detected in water samples were lower than the water quality criteria values for aquatic organisms protection, which were reported in Giesy et al., 2010. A positive linear regression (r²=0.99, p<0.05) and a trophic magnification factor of 28.25 were observed between PFOS concentrations and trophic levels of collected biota. The mean bioconcentration factor (BCF) of PFOS were extended from 14,745±21,366 (in plankton) to 517,476±705,036 (in crucian carp blood). According to the method of Moermond et al., 2010 and the received BCF of sensitive medaka fish in this study, we suggested the MPCsp,water of 0.083 ng/L for PFOS in Korea freshwater ecosystems.
-
-
-
-
Mapping of Quantitative Trait Loci Affecting Growth Traits in a Japanese Native Chicken Cross
Rikimaru, K.,Sasaki, O.,Koizumi, N.,Komatsu, M.,Suzuki, K.,Takahashi, Hideaki Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.10
The Hinai-dori is a breed of chicken native to Akita Prefecture, Japan. An $F_2$ resource population produced by crossing low- and high-growth lines of the Hinai-dori breed was analyzed to detect quantitative trait loci (QTL) for growth traits. Highly significant QTLs for body weight at 10 and 14 weeks of age and average daily gain between 4 and 10 weeks and between 10 and 14 weeks of age were accordingly mapped in a common region between ADL0198 and ABR0287 on chromosome 1 and between MCW0240 and ABR0622 on chromosome 4, respectively. A significant QTL for body weight at 4 weeks of age and a significant QTL for average daily gain between 0 and 4 weeks of age were mapped for the first time to the same region flanking ABR0204 and ABR0284 on chromosome 1. These QTLs are good candidates for application in the development of marker-assisted selection strategies for increasing growth efficiencies in the Hinai-dori breed and native breeds of chickens in Asia.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
