538 research outputs found

    Characteristics of Photosynthate Partitioning during Chloroplast Development in Avena

    Full text link

    Contributions of Three Starch Branching Enzyme Isozymes to the Fine Structure of Amylopectin in Rice Endosperm

    Get PDF
    Three starch branching enzyme (BE) isozymes, BEI, BEIIa, and BEIIb, are involved in starch biosynthesis in rice endosperm. Past in vivo and in vitro studies have suggested that each BE isozyme plays a distinct role in forming the fine structure of amylopectin. To elucidate more details of their roles, we prepared DNA constructs in which all the possible combinations of the expressions of these three isozymes were suppressed in developing rice endosperm. Analysis of the chain-length distributions of amylopectin produced under these various conditions confirmed the contributions of the individual BE isozymes to the fine structure of amylopectin in rice endosperm. Among these isozymes, the impact of loss of BEIIb activity on amylopectin fine structure was most remarkable and indicated that it plays a specific role in the synthesis of short chains with a 6–13 degree of polymerization (DP). The contribution of BEI to the amylopectin synthesis was unclear when only BEI activity was reduced. It was clear, however, when both BEI and BEIIb activities were substantially inhibited. The DP11-22 intermediate chains were markedly reduced in the ΔBEI/BEIIb line compared with the ΔBEIIb line, indicating that BEI plays a distinct role in the synthesis of these intermediate chains. Although no substantial change in amylopectin chain profile was detected in the ΔBEIIa line, the role of BEIIa could be deciphered by analyzing amylopectin fine structure from the ΔBEI/BEIIa/BEIIb line in comparison to that from ΔBEI/BEIIb line. This strongly suggests that BEIIa compensates for the role of BEI, rather than that of BEIIb, by forming intermediate chains of DP11-22. In addition, the new possibility that BEIIa is involved in the formation of starch granules in rice endosperm was suggested because the onset temperature for gelatinization of starch granules in the ΔBEIIa/BEIIb line was significantly higher than that in the ΔBEIIb line. In summary, the present study highlights the distinct roles of BEI, BEIIa, and BEIIb in the synthesis of amylopectin in developing rice endosperm

    A new crystal plasticity constitutive equation based on crystallographic misorientation theory

    Get PDF
    Since plastic deformation of polycrystal sheet metal is greatly affected by its initial and plastic deformed textures, multi-scale finite element (FE) analysis based on homogenization with considering micro-polycrystal morphology is required [1]. We formulated a new crystal plasticity constitutive equation to introduce not only the effect of crystal orientation distribution, but also the size of crystal grain and/or the effect of crystal grain boundary for the micro-FE analysis. The hardening evolution equation based on strain gradient theory [2], [3] was modified to introduce curvature of crystal orientation based on crystallographic misorientation theory. We employed two-scale structure, such as a microscopic polycrystal structure and a macroscopic elastic/plastic continuum. Our analysis code predicts the plastic deformation of polycrystal metal in the macro-scale, and simultaneously the crystal texture and misorientation evolutions in the micro-scale. In this study, we try to reveal the relationship between the plastic deformation and the microscopic crystal misorientation evolution by using the homogenized FE procedure with the proposed crystal plasticity constitutive equation. The crystallographic misorientation evolution, which affects on the plastic deformation of FCC polycrystal metal, was investigated by using the multi-scale FE analysis. We confirmed the availability of our analysis code employing the new constitutive equation through the comparison of a uniaxial tensile problem with the numerical result and the experimental one

    Regulation of ADP-Glucose Pyrophosphorylase from Chlorella vulgaris

    Full text link

    The relation between mindfulness and the fatigue of women with breast cancer: path analysis

    Get PDF
    Background: Although fatigue is a common and distressing symptom in cancer survivors, the mechanism of fatigue is not fully understood. Therefore, this study aims to investigate the relation between the fatigue and mindfulness of breast cancer survivors using anxiety, depression, pain, loneliness, and sleep disturbance as mediators. Methods: Path analysis was performed to examine direct and indirect associations between mindfulness and fatigue. Participants were breast cancer survivors who visited a breast surgery department at a university hospital in Japan for hormonal therapy or regular check-ups after treatment. The questionnaire measured cancer-related-fatigue, mindfulness, anxiety, depression, pain, loneliness, and sleep disturbance. Demographic and clinical characteristics were collected from medical records. Results: Two-hundred and seventy-nine breast cancer survivors were registered, of which 259 answered the questionnaire. Ten respondents with incomplete questionnaire data were excluded, resulting in 249 participants for the analyses. Our final model fit the data well (goodness of fit index = .993; adjusted goodness of fit index = .966; comparative fit index = .999; root mean square error of approximation = .016). Mindfulness, anxiety, depression, pain, loneliness, and sleep disturbance were related to fatigue, and mindfulness had the most influence on fatigue (β = − .52). Mindfulness affected fatigue not only directly but also indirectly through anxiety, depression, pain, loneliness, and sleep disturbance. Conclusions: The study model helps to explain the process by which mindfulness affects fatigue. Our results suggest that mindfulness has both direct and indirect effects on the fatigue of breast cancer survivors and that mindfulness can be used to more effectively reduce their fatigue. It also suggests that health care professionals should be aware of factors such as anxiety, depression, pain, loneliness, and sleep disturbance in their care for fatigue of breast cancer survivors. Trial registration: This study was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN number. 000027720) on June 12, 2017

    AN AUTOPSY CASE OF PORTOPULMONARY HYPERTENSION ASSOCIATED WITH ALCOHOLIC LIVER CIRRHOSIS

    Get PDF
    We report an autopsy case of pulmonary pexogenic arteriopathy associated with portal hypertension due to alcoholic liver cirrhosis, termed portopulmonary hypertension (PPHT). A 49-year-old man who has had alcoholic liver cirrhosis for 10 years complained of severe dyspnea (Fletcher-Hugh-Jones V). Chest CT revealed marked enlargement of bilateral hilar pulmonary arteries and cardiomegaly associated with right ventricular hypertrophy. The patient died from hepatic. encephalopathy and respiratory failure. Autopsy c1early revealed the wall thickness of pulmonary small vessels diffusely in peripheral fields on cut surfaces and marked dilatation of the main pulmonary artery, together with liver cirrhosis. Microscopically, the pulmonary small arteries demonstrated grade 5 pulmonary plexogenic arteriopathy inc1uding plexiform lesions and a micronodule resembling an arachnoid granulation or meningioma throughout the lungs. This case suggested that a typical plexogenic arteriopathy morphologically and definitely contributed to confirm PPHT, although the patient was c1inically suspected of hepatopulmonary syndrome (HPS)

    Molecular regulation of starch metabolism

    Get PDF
    Starch is the second most abundant biomass next to cellulose and composed of amylopectin, a highly branched glucan, and amylose, an essentially linear glucan. The former and the latter glucans usually account for approximately 65–85% and 15–35% of the total starch, respectively. During the last three decades the basic scheme of starch biosynthesis has been established based on numerous biochemical, genetic, and molecular biological approaches worldwide using a variety of higher plants and algae. It is well known that after the synthesis of ADPglucose by ADPglucose pyrophosphorylase (AGPase), amylopectin’s fne structure is formed by concerted actions of multiple isozymes from three classes of enzymes, starch synthase (SS), starch branching enzyme (BE), and starch debranching enzyme (DBE), and that amylose is synthesized by mainly granule-bound SS (GBSS). In addition to the roles of starch biosynthetic isozymes, the contributions of α-glucan phosphorylase, α-glucan, water dikinase, phosphoglucan, water dikinase, pyruvate, phosphate dikinase, α-amylase, and carbohydrate-binding modules have been documented. Information on the whole genome sequence and omics analyses are available in main plant species. All these results revealed the roles of key biosynthetic isozymes of SS, GBSS, BE, and DBE and subunits of AGPase to starch biosynthesis, and presently we know to what extent the fne structure of starch molecules and the internal structure and physicochemical properties of starch granules as well as starch amounts can be modifed in accord with the activity levels of these isozymes and subunits. However, in spite of numerous past investigations, the regulation of the network of enzymatic reactions has not been fully understood. To resolve the complex mechanisms, we need to examine several topics such as redundancy and supplementary functions of multiple isozymes, enzymeenzyme interaction(s), and regulatory factors controlling catalytic and specific activities of individual isozymes, temporal and spatial co-expression of multiple isozymes, post-translational modifcation of enzymatic capacities such as phosphorylation, glycosylation, and redox state. There are still lots of uncertainties in the understanding of the initiation of starch biosynthesis.Fil: Nakamura, Yasunori. Akita Prefectural University; JapónFil: Steup, Martin. Universitat Potsdam; AlemaniaFil: Colleoni, Christophe. Université de Lille; FranciaFil: Iglesias, Alberto Alvaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Bao, Jinsong. Zhejiang University; ChinaFil: Fujita, Naoko. University of Guelph; CanadáFil: Tetlow, Ian. University of Guelph; Canad

    Optimization of Ladle Tilting Speed for Preventing Temperature Drops in the Die Casting Process

    Get PDF
    In die casting, molten metal poured into a shot sleeve is pressed into a mold by a plunger at high speed. The temperature of the metal drops significantly while it is being poured from the ladle to the shot sleeve, resulting in casting defects such as misrun flow lines. Although it is important to control the temperature at all stages of the process, a method for minimizing temperature loss has not yet been clarified to date. In this study, the cause of the temperature drop in the shot sleeve was clarified, and a method of optimizing the ladle tilting speed was proposed to prevent temperature drop. First, experiments were conducted to measure the decrease in metal temperature in the sleeve during pouring. These experiments revealed that the metal cools significantly from the moment it touches the shot sleeve. Therefore, the time from the first contact between the shot sleeve and the metal to the start of pouring was set as the objective function. A genetic algorithm was then used to derive the optimal ladle tilting speed pattern to suppress the temperature drop. This analysis confirmed that the metal was poured without flowing out or running ahead and that the immediate liquid level vibration after pouring was suppressed, thus ensuring stable pouring
    corecore