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41.
Roger Wigren Hans Elwing Ragnar Erlandsson Stefan Welin Ingemar Lundstrm 《FEBS letters》1991,280(2):225-228
It is shown that scanning force microscopy (SFM), operated in the attractive mode, can be used to obtain high resolution pictures of adsorbed fibrinogen molecules on solid surfaces, without the need for staining or special microscope grids. SFM also reveals the three-dimensional structure of the adsorbed molecules. Two forms of adsorbed fibrinogen are demonstrated on hydrophobic silicone dioxide surfaces; a trinodular about 60 nm long and a globular with about a 40 nm diameter. Polymeric networks formed after storage of the surface with adsorbed fibrinogen in PBS for 11 days are also shown. The SFM-results for the trinodular structure suggest the existence of loops or peptide chains extending outside the basic structure of the fibrinogen molecule. 相似文献
42.
Stephen R. Cohen 《Journal of neurochemistry》1980,35(4):1008-1012
Concentrative influx of γ-aminobutyric acid (GABA) and α-aminoisobutyric acid (AIB) into incubated mouse cerebrum slices is decreased when pyruvate is substituted for glucose. Influx of GABA from pyruvate medium is not increased by presence of glucose, 2-deoxy-d -glucose (2-DOG), or 3-O-methyl-d -glucose (3-O-MeG). Influx of AIB is restored to the rate from glucose medium if 2-DOG is present initially, but is not restored if 2-DOG is added with AIB. Influx is not restored if 3-O-MeG is present initially, but is restored if 3-O-MeG is added with AIB. Influx is restored if glucose is present initially or is added with AIB. 相似文献
43.
The ATPase complex of submitochondrial particles exhibits activity transitions that are controlled by the natural ATPase inhibitor (Gómez-Puyou, A., Tuena de Gómez-Puyou, M. and Ernster, L. (1979) Biochim. Biophys. Acta 547, 252–257). The ATPase of intact heart mitochondria also shows reversible activity transitions; the activation reaction is induced by the establishment of electrochemical gradients, whilst the inactivation reaction is driven by collapse of the gradient. In addition it has been observed that the influx of Ca2+ into the mitochondria induces a rapid inactivation of the ATPase; this could be due to the transient collapse of the membrane potential in addition to a favorable effect of Ca2+-ATP on the association of the ATPase inhibitor peptide to F1-ATPase. This action of Ca2+ may explain why mitochondria utilize respiratory energy for the transport of Ca2+ in preference to phosphorylation. It is concluded that the mitochondrial ATPase inhibitor protein may exert a fundamental regulatory function in the utilization of electrochemical gradients. 相似文献
44.
B. Labedan K.B. Heller A.A. Jasaitis T.H. Wilson E.B. Goldberg 《Biochemical and biophysical research communications》1980,93(2):625-630
DNA penetration from T4 phage adsorbed to was measured at different membrane potentials. There was a precipitous reduction in DNA penetration between 110 mV and 60 mV. This threshold of membrane potential for DNA penetration is independent of ΔpH and rather insensitive to external pH between 6 and 8. 相似文献
45.
Michael L. May Peter J. Wilkin James E. Heath Bill A. Williams 《Journal of insect physiology》1980,26(4):257-265
The tethered and free flight of Manduca sexta were studied during period 1,2, and 0 times normal gravity (g) produced in an aeroplane by flying through parabolic trajectories. Moths in tethered flight did not change their aerodynamic output in response to increases or decreases in gravity. Some moths in free flight at 0 g maintained a position in the box by flying against a surface, or into the angle between two surfaces. In the absence of gravity as an orienting stimulus, the positive dorsophotic response to light was dominant. As the period of 0 g continued, moths were increasingly likely to periodically reduce the amplitude of their wingbeat and/or stop flying, for the equivalent of a few wingbeats. Only at 0 g, moths very occasionally spread their wings and floated freely for a few seconds. At 0 g moths retained control of rolling and yawing movements but stability in pitch was greatly reduced or absent. 相似文献
46.
Changes in the proton-motive force cause a transient change in the motile behavior of Bacillus subtilis cells. Both an increase and a decrease in the proton-motive force cause transient tumbling. Simultaneous decrease of proton-motive force and increase of attractant concentration lessens the response toward the attractant. A simultaneous increase of proton-motive force and increase of attractant concentration prolonges the response toward attractant. A hypothesis explaining the various effects is given.Abbreviations KT medium
potassium taxis medium
- NaT medium
sodium taxis medium
- HT medium
acidic taxis medium
- OHT medium
alkaline taxis medium
- DNP
2,4-dinitrophenol 相似文献
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All motile stages of Pratylenchus coffeae infected mature and immature tissues of Citrus jambhiri (rough lemon) seedling tap roots. The nematodes fed primarily in the cortex and colonized in pockets or cavities. Intra- and intercellular migration within the cortex occurred in either direction from the point of entry. When P. coffeae invaded a root tip the meristem often was destroyed and lateral root initiation usually occurred near the destroyed root tip. Males were essential for reproduction and survived at least 2 1/2 months within root tissues, but with males alone used as inoculum, no cortical pockets were formed. On infected trees in the field P. coffeae were most numerous in C. jambhiri feeder roots. 相似文献
50.