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The dependence of membrane potentials on changes in the extra-cellularK+ concentration [K+]e was investigated in potato tuber sliceswith dripping perfusion, and in growing Vigna hypocotyl segmentswith pressurized intra-organ perfusion methods. Only under anoxiawere the membrane potential of potato tuber slices and the electricpotential difference between the parenchyma symplast and xylem(Vpx) of Vigna hypocotyl segments depolarized markedly (46 mVand 42 mV/log[K+]e unit, respectively) with increasing [K+]eabove the critical values. The electric potential differencebetween the parenchyma symplast and organ surface (Vps of thehypocotyl segments remained nearly unchanged up to 30 mEq [K+]e.Under highly aerobic conditions the membrane potentials wererelatively independent of [K+]e except at very high K+ concentrations.Vps showed even hyperpolarization with the increasing KCl concentrationin the perfusion solution that is not in direct contact withthe surface membrane of the parenchyma symplast. The respiration-dependentelectrogenic components of the membrane potentials regularlyincreased with the increasing [K+]e. A voltage-dependent homeostaticcontrol of membrane potential is discussed. (Received August 13, 1984; Accepted December 21, 1984) 相似文献
34.
Tanaka Kiyoshi; Suda Yoshiko; Kondo Noriaki; Sugahara Kiyoshi 《Plant & cell physiology》1985,26(7):1425-1431
The relationship between O3 tolerance and the chloroplast H2O2scavenging system (PS I 相似文献
35.
The Escherichia coli cytochrome b556 gene, cybA, is assignable as sdhC in the succinate dehydrogenase gene cluster 总被引:2,自引:0,他引:2
Hiroshi Murakami Kiyoshi Kita Hiroshi Oya Yasuhiro Anraku 《FEMS microbiology letters》1985,30(3):307-311
Abstract The cytochrome b556 -deficient mutant Escherichia coli K12 strain TK3D11 [7] could not grow with succinate as the sole carbon source, but could grow well on dl -lactate. This finding suggested that cytochrome b556 is primarily responsible for oxidative metabolism and utilization of succinate. 24 Amino acid residues at the amino-terminal of purified cytochrome b556 were determined. This sequence coincided completely with amino acid residues 4 to 27, predicted from the DNA sequence of the sdhC gene, one of the unassigned open reading frames of the sdh gene cluster recently reported by Wood et al. [16]. Based on these and other results, we concluded that cybA , the gene for cytochrome b556 , is assignable as sdhC . 相似文献
36.
Spider toxin (JSTX) on the glutamate synapse 总被引:1,自引:0,他引:1
A new neurotoxin (JSTX) was separated from spider (Nephila clavata, Joro spider) venom. JSTX irreversibly suppressed the excitatory postsynaptic potential (EPSP) and the glutamate potential in the lobster neuromuscular junction with high degree of specificity. The threshold concentration for suppressing EPSPs corresponds to a small fraction of the toxin in a venom gland, roughly estimated as low as 10(-10) M/l. 10(-10) M/l. In the giant synapse of squid stellate ganglion JSTX suppressed EPSPs without affecting the antidromic response. Glutamate-induced membrane depolarization was blocked by JSTX. In mammalian brain slice preparation, JSTX suppressed the orthodromic spike response but failed to affect on the antidromic spike in the hippocampal pyramidal neuron of CA1 and CA3 region. The above results strongly support the view that the squid giant synapse and synapses in the hippocampal pyramidal neuron are mediated by glutamate. 相似文献
37.
Hiroshi Murakami Kiyoshi Kita Hiroshi Oya Yasuhiro Anraku 《Molecular & general genetics : MGG》1984,196(1):1-5
Summary The amounts of cytochrome b556 in the cytoplasmic membranes of several Escherichia coli K12 strains having F-prime factors and a lambda transducing phage were determined. The amount was amplified about two-fold in strains having F100-12 and F152, but not in strains having F100-11, F8 and psu
+
2glnS
+. The strain TK3D11, which lacks the kdp-gltA region (deletion D-01) of the E. coli chromosome, did not synthesize cytochrome b556 at all. From these results, the gene cybA encoding cytochrome b556 was located in the kdp-gltA region.In the cytochrome b556-deficient mutant, a novel b type cytochrome, cytochrome b561 which is a product of the gene cybB, was identified. It seems to function as a physiological electron transferring cytochrome in place of cytochrome b556 in this mutant.Abbeviations HPLC
high performance liquid chromatography
- EDTA
ethylenediamine tetraacetic acid
- SDS
sodium dodecyl sulfate
- NADH
reduced form of nicotinamide adenine dinucleotide 相似文献
38.
S100a0 (αα) Protein Is Present in Neurons of the Central and Peripheral Nervous System 总被引:2,自引:1,他引:1
The cellular distribution of S100 subunits in human brain and peripheral nerves was studied by means of an immunohistochemical technique using antibodies specific to the alpha subunit or the beta subunit of S100 protein. The results indicate that the distribution of the alpha subunit and the beta subunit is different among cell types in the nervous tissue, and that neurons in the brain and peripheral nerves contain only the alpha subunit, or S100a0 protein. The subunit distribution also appears to be different at an intracellular level, where the immunoreaction products for the alpha subunit show granular arrangement whereas those for the beta subunit are found diffusely in the cytoplasm. 相似文献
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