ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00115.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00116.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00117.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00118.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe principles of photoacoustic spectroscopy are outlined. This new and still developing technique enables one to detect non‐radiative de‐excitation processes. It is possible to distinguish between signals emenating from different depths of the sample. In plant science photoacoustic spectroscopy has mainly been applied in photosynthesis research. Here it allows the detection of gross oxygen evolution and gives information about the energy balance of the primary photosynthetic react

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00119.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractHomeostasis of a cytosolic substrate (e.g. H+) can be achieved by transmembrane transport. Control theory implies that the involved activation and deactivation of a transport molecule (as observed in patch clamp experiments) requires input of energy. This energy can be provided by a so‐called non‐consuming binding site or by other sources and is necessary in order to achieve asymmetric rate‐constants required for an efficient integral controller. Another important prediction of control theory is the involvement of two different binding sites for the substrate and its antagonist in order to define a non‐zero set‐point.The kinetic behavior of a homeostatic feed‐back loop is calculated. The system can generate weakly damped oscillations or exponential responses. Numerical calculations using data from the pH‐controller ofNitellashow that a buffer is necessary in order to explain the observed long periods of 1 hour/cycle. Theoretically, the damping factor can originate from shunting transporters or from special terms of the biochemical reaction schemes. The effect of shunting transport systems is demonstrated in the case of data from the light‐effect on H+

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00120.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractDimensions and area densities of membrane particles were studied by electron microscopy of replicas of freeze‐fractured suspensions of tonoplast vesicles ofMesembryanthemum crystallinumL. in the C‐3 state and after induction of crassulacean acid metabolism (CAM) by salinity. The results are compared with the relative contribution of tonoplast‐ATPase protein to total membrane protein obtained from integration of elution profiles in size‐exclusion chromatography. Coverage of tonoplast area by globular membrane particles was 20% and 36 % and ATPase in relation to total membrane protein was 33 % and 35 % in C‐3 and CAMM. crystallinum, respectively. Thus, by order of magnitude, it is most likely that the particles represent the ATPase. InKalanchoë daigremontianaHamet et Perrier de la Bâthie the ATPase also constituted 36% of total tonoplast protein. Induction of CAM inM. crystallinumwas associated with an increase in specific ATPase activity of the tonoplast and an increase of the size and area coverage of tonoplast particles, whereas the relative contribution of ATPase protein to total tonoplast protein and the molecular mass of the ATPase holoenzyme, as seen in size‐exclusion chromatography, remained alm

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00121.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractTonoplast preparations were obtained from leaves ofHordeum vulgare(C3),Kalanchoë daigremontiana(obligate CAM) andMesembryanthemum crystallinum(C3and inducible CAM). Lipid analyses showed reproducible patterns comprising free sterols, glycolipids of plastidic origin, glucose‐containing lipids (steryl glucoside, acylated steryl glucoside, cerebroside) and phospholipids. Predominant components were sterols, cerebrosides, phosphatidyl choline and phosphatidyl ethanolamine. Very long chain fatty acids were found in phosphatidyl serine and hydroxy fatty acids in cerebrosides. Isolation of tonoplasts via protoplasts and vacuoles may have resulted in reduced levels of free sterols. The data show a similarity between tonoplasts and plasma membranes with respect to lipid profiles. Lipid composition was neither affected by different CO2‐fixation mechanisms nor by salt‐induced changes inMesembryanthemum crysta

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00122.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe functional molecular weight of the plasma membrane Ca2+‐ATPase of radish (Raphanus sativusL.) seeds was determined by measuring the Ca2+‐dependent ATPase activity and the MgATP‐dependent Ca2+transport activity of membrane samples irradiated, in the lyophilized state, with γ rays from [60Co] source. The results gave a target size of about 270,000 dalton for both the measured activities, thus confirming (i) that both activities are catalyzed by the same enzyme and (ii) the similarity between the plasma membrane Ca2+‐ATPase of higher plants and that of the eryt

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00123.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractSubcellular concentrations of free amino acids in internodal cells of a Characeae,Chara corallina, were measured in the dark and in the light. Using an intracellular perfusion technique, we measured concentrations of amino acids in the vacuole, in the flowing sol endoplasm and in the cortical gel layer. The sol endoplasm was predominantly the cytosol. On the basis of microscopic observations, the gel layer appeared to be occupied predominantly by a layer of chloroplasts, while the sol endoplasm was free from chloroplasts.Both in the light and in darkness, the major amino acids in the internodal cells were isoasparagine, glutamic acid, aspartic acid, serine, glycine and alanine, as reported by Sakano and Tazawa (1984). The same major amino acids are found in each of the three compartments. The pattern of distribution of amino acids in the vacuole was similar to that in the sol endoplasm, but quite different from that in the gel layer. The total level of amino acids in the light was lower than that in darkness. The amino acid composition did not change very much, but the subcellular distribution of amino acids differed significantly between cells subjected to illumination and those kept in the dark. Concentrations of amino acids in both the vacuole and the gel layer decreased, whereas those in the sol endoplasm were almost constant.

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00124.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY