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61.
Prof. Salomon Bartnicki-Garcia Ildiko Bartnicki Rafael Sentandreu 《Current microbiology》1985,12(3):141-145
Whether intact or dissociated with digitonin, chitosomes isolated from the fungusMucor rouxii lack the ability to bind concanavalin A. The absence of external or internal concanavalin A-binding sites distinguishes the chitosome membrane no only from plasma membrane but also from membranes of other organelles (endoplasmic reticulum, mitochondrion, vacuole). This differential binding ability was used to partially separate chitosomal chitin synthetase from major membranes in a crude cell-free extract ofM. rouxii. 相似文献
62.
Animal community structure as a function of stream size 总被引:1,自引:1,他引:0
Christer Brönmark Jan Herrmann Björn Malmqvist Christian Otto Per Sjöström 《Hydrobiologia》1984,112(1):73-79
The species-area relationship of the island biogeography theory was calculated for macroinvertebrates in 22 coastal, adjacent streams. A z-value of 0.19 was obtained. The low z-value was probably a consequence of the short distances between streams as well as high dispersal rates. In addition, a cluster analysis based on the dissimilarity of species assemblages showed that stream size was of prime importance in categorizing the streams. To a smaller extent water quality affected the community structure in the streams. 相似文献
63.
Jan Dahmén Torbjörn Frejd Göran Magnusson Ghazi Noori Anne-Sofie Carlström 《Carbohydrate research》1984,125(2):237-245
The applicability of 2-bromoethyl glycosides in carbohydrate synthesis is demonstrated by the synthesis of glycosides of alpha-L-Fuc-(1----2)-D-Gal and beta-D-Gal-(1----4)-D-GlcNAc. The bromoethyl aglycon was transformed into the methoxycarbonylethylthioethyl spacer, which allowed coupling of the sugars to proteins (BSA and KLH). 相似文献
64.
Lars Olof Björn 《Physiologia plantarum》1984,60(3):369-372
Experiments by several authors on the effects of polarized light on phytochromemediated responses in fern gametophytes and in the green alga Mougeotia have earlier been interpreted as showing that the transition moment of phytochrome in the Pr form is parallel to the plasmalemma, but perpendicular to the plasmalemma for the Pfr form of phytochrome. It is now shown that the experimental results can be interpreted differently, and that they are also consistent with a chromophore rotation of about 30° (instead of 90°), as found for immobilized phytochrome molecules in vitro. Thus there is no evidence for a rotation of the whole phytochrome protein. For the gametophyte of Adiantum it is calculated that the Pr transition moment is inclined 17° to the plasmalemma, and the Pfr transition moment ca 50°, corresponding to an in vivo chromophore rotation of ca 33°; however, these values are very approximate. 相似文献
65.
Photosynthesis and nitrogen utilization in exponentially growing nitrogen-limited cultures of Lemna gibba 总被引:2,自引:0,他引:2
The photosynthetic performance and nitrogen utilization of Lemna gibba L. G3 adapted to limited nitrogen supply was studied. The plants were adapted to two levels of nitrogen limitation where the nitrogen addition rates were calculated to sustain relative growth rates (RGR) of 0.15 day?1 and 0.25 day?1, respectively. The photosynthetic performance of these cultures was compared to nitrogen-sufficient cultures with an average RGR of 0.32 day?1. Plants transferred from nitrogen-sufficient conditions attained RGR values corresponding to the nitrogen addition rates after 6 to 10 days. Light-saturated net photosynthesis declined during adaptation according to the drop in growth rate, and a concomitant decrease in the respiration rate was recorded. The efficiency of net photosynthesis on a dry weight basis increased with increased nitrogen supply, whereas it was the same in all cultures when expressed on a chlorophyll basis. The light compensation point was unaffected by the nitrogen regime. Limited nitrogen supply resulted in an increased proportion of dry matter in the roots, which led to decreased leaf area ratios. The net assimilation rates also decreased, but not to the same extent as the leaf area ratios. Growth-limiting amounts of nitrogen were added to the cultures once daily, and the net influx of N was higher than the requirement for N, also in adapted cultures with a steady growth rate. This resulted in transient, periodic fluctuations in the NO3?, NH4+ and amino acid pools. Also the rates of NO3? reduction and NH4+ assimilation fluctuated as did the amino acid assimilation which paralleled NH4+ assimilation. The role of flux rates over the plasmalemma and tonoplast for control of nitrogen assimilation rates are discussed. 相似文献
66.
Conidiation in Alternaria cichorii Nattras is reversibly stimulated by near ultraviolet radiation (NUV, ca 313 nm) and inhibited by blue light (ca 450 nm) and seems to be a mycochrome-mediated process. After induction with plane-polarized NUV, blue light polarized perpendicularly to the NUV was more effective in counteracting the induction than was blue light polarized parallel to the NUV. From this the conclusions are drawn that (a) both the blue-absorbing component (presumably a flavo-protein) and the PNUV of the mycochrome system are membrane-bound and that (b) the transition moment associated with blue light absorption in the presumed flavoprotein forms an angle of at least 53° with the transition moment associated with NUV absorption in PNUV . 相似文献
67.
T cell synergy in the primary MLR: proliferative kinetics, effector cell generation, and IL 2 production 总被引:1,自引:0,他引:1
D R Salomon D J Cohen J M Williams C B Carpenter 《Journal of immunology (Baltimore, Md. : 1950)》1984,133(6):3075-3083
A primary rat MLR was initiated, and on each of 8 consecutive days during the evolving culture, an aliquot of cells was separated into its constitutive helper/inducer (W3/25+) and suppressor/cytotoxic (OX8+) T cell subsets by a monoclonal antibody, Degalan-bead immunoadsorbent column technique. This allowed a detailed kinetic analysis of T cell proliferation, the generation of effector cells, and the production of IL 2 by each subset relative to net whole culture supernatant IL 2 activity. The primary MLR demonstrates an early period of helper/inducer cell proliferation, IL 2 production and accumulation, followed by a period of suppressor/cytotoxic cell (OX8+) proliferation and IL 2 consumption during which there are distinct waves of allospecific suppressor, followed by cytotoxic activity. If fresh T cells of the helper/inducer or suppressor/cytotoxic phenotype were preseparated and then cultured alone with irradiated allogeneic stimulator cells, proliferation was noted in both subsets despite no demonstrable IL 2 activity in cultures of the suppressor/cytotoxic cells. Finally, a suppressed primary MLR exhibited proliferative inhibition of both T cell subsets. 相似文献
68.
Isaksson Axel Philips Anna–Carin Göransson Eva Björkenfeldt Henrik 《Acta veterinaria Scandinavica》1987,28(3-4):455-457
The electrical conductivity (EC) of milk is mainly a function of the electrolyte concentration in the milk and therefore raised in mastitis. The present investigation was aimed at elaborating, if possible, a diagnostic model for screening purposes based on EC determinations and consistent with the diagnostic procedures and interpretations commonly used in laboratory milk diagnosis in the Nordic countries (Klastrup 1975). According to this diagnosis (here called reference diagnosis) cell numbers above 300,000/ml (cell count or the corresponding CMT-score) in foremilk quarter samples during the main part of the lactation period and significantly above the lowest value on within-udder comparison during late lactation are considered indicative of mastitis and bacteriological examinations are made when called for. 相似文献
69.
Four major prostanoids (6-keto-PGF1 alpha, PGE2, PGF2 alpha and TXB2) were measured by specific radioimmunoassays in the outputs from human umbilical vessels perfused in vitro. As evaluated by scanning electron microscopy (SEM) only few blood platelets were attached to the vessel wall. After an initial flush with decreasing concentrations of all four prostanoids, a stable stage was reached, lasting for 4-5 hours. During this stage the production could be inhibited by indomethacin and only slightly stimulated with arachidonic acid. The TXA2 synthetase inhibitor UK 38485 depressed the TXB2 production, while only slightly affecting the other three prostanoids at very high concentrations. The arteries produced relatively more 6-keto-PGF1 alpha than did the vein. 相似文献
70.
Johan Kumlien Torbjörn Frejd Göran Magnusson David Zopf Arne Lundblad 《Glycoconjugate journal》1986,3(1):85-94
The tetrasaccharide, Glc1-6Glc1-4Glc1-4Glc, denoted (Glc)4, is a limit dextrin formed by amylolytic degradation of glycogen. In order to evaluate the possible clinical importance of (Glc)4 excretion as an indicator of certain physiological and pathological conditions, we have developed a new rapid and inexpensive immunoassay using a monoclonal antibody raised against (Glc)4 glycosidically-linked to a carrier protein. As the antibody is highly specific, it can be used to measure native (Glc)4 directly, without the chemical reduction step required in previous methods. A new type of non-equilibrium ELISA inhibition test was developed based on the capacity of free (Glc)4 to decrease initial rates of antibody binding to (Glc)4-coated microtiter wells. The method is highly reproducible and is as sensitive and accurate as the gas chromatography method or radioimmunoassay used previously.Abbreviations (Glc)4
Glc1-6Glc1-4Glc1-4Glc
- KLH
keyhole limpet hemacyanin
- BSA
bovine serum albumin
- PEG
polyethylene glycol 相似文献