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51.
Hiroyuki Uno Yumiko Ohno Tsuneo Yamada Kensaku Miyamoto 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1991,169(2):231-239
Summary The responses of neurons in field L in the auditory neostriatum of the mynah bird, Gracula religiosa, were recorded during presentation of intact or manipulated mimic voices. A typical mimic voice konnichiwa elicited responses in most of the neurons. Neurons in the input layer (L2) of field L showed many peaks on peristimulus time histograms while those in other layers (L1 and L3) exhibited only one or two peaks. Several neurons in L1 and L3 responded only to the affricative consonant /t/ in the intact mimic voices. They did not respond to the affricative consonant in the isolated segment or to the one in the playbacked voice in reverse. Forty-five percent of the neurons (33/ 73) decreased in firing rates at the affricative consonant in the isolated segment compared with in the intact voice. Some of these neurons, in which neither the affricative consonant in the isolated segment nor bursts of noise alone elicited responses, exhibited clear phasic responses to /t/ in the case when bursts of noise with particular central frequencies preceded the affricative consonant. The responsiveness of these neurons appears to receive temporal facilitation. These results suggest that these neurons code the temporal relationship of speech sound.Abbreviations
HVc
hyperstriatum ventrale, pars caudale
-
TFN
temporally facilitated neuron
-
TSN
temporally suppressed neuron 相似文献
52.
A prospective study of the value of sputum cytology in the diagnosis of squamous cell carcinoma of the larynx and hypopharynx is reported. Sputum cytology established the diagnosis in 63.5% of the patients with laryngeal lesions and in 77.4% of the patients with hypopharyngeal lesions. In laryngeal cancer, a positive diagnosis by sputum cytology was related to clinical T factors (according to the TNM classification): while only 29.4% of T1 lesions were positively detected by sputum cytology, 63.3% of T2 lesions, 69.7% of T3 lesions and 79.2% of T4 lesions were so detected. In hypopharyngeal cancer, there was no discernible relationship between sputum cytodiagnosis and clinical T factors. Generally, there was only a small number of cancer cells present in the sputum in these cases. Some of the squamous cancer cells were not very conspicuous and would require careful screening of the sputum specimens to be detected. 相似文献
53.
Type B nucleoside-diphosphatase of rat brain. Purification and properties of an enzyme with high thiamin pyrophosphatase activity 总被引:1,自引:0,他引:1
Type B nucleoside-diphosphatase was purified from membranes of rat brain by solubilization with a non-ionic detergent and successive column chromatographies on DEAE-cellulose DE-52, concanavalin-A-Sepharose, Bio-Gel HT, blue-Sepharose CL-6B, chelating Sepharose 6B, Ultrogel AcA44 and TSK gel G3000 SW. The purified enzyme gave a single protein band on SDS/polyacrylamide gel electrophoresis and its molecular mass was estimated to be 75 kDa. It hydrolyzed thiamin diphosphate as well as GDP, IDP and UDP. Thiamin diphosphate (TPP) was hydrolyzed twice as efficiently as nucleoside diphosphates in the presence of Mn2+ at pH 7.4. The Km values for TPP, GDP, IDP and UDP were 0.66, 0.40, 0.54 and 1.06 mM respectively. ATP, ADP and pyridoxal 5'-phosphate inhibited thiamin-pyrophosphatase activity competitively and their Ki values were 2.3 mM, 1.0 mM and 0.59 mM respectively. The optimum pH of thiamin-pyrophosphatase activity was 7.4 in the presence of Mn2+ and that of GDP-hydrolytic activity was 6.5 in the presence of Mg2+. 相似文献
54.
S Matsuda 《Journal of biochemistry》1988,104(6):989-990
Ca2+-binding of S-100 protein was studied using a Ca2+ electrode at pH 6.80. In the presence of 0.1 M KCl and 10 mM MgCl2 (ionic strength 0.13), Ca2+-binding to S-100 protein occurred in three steps with positive cooperativity. The numbers of bound Ca2+ ions in the three steps were 2, 2, and 4. The Ca2+-binding constants were 6.9 x 10(3) M-1, 2.9 x 10(3) M-1, and 3.7 x 10(2) M-1, respectively. The Ca2+-binding constants of the first and second steps obtained in the presence of 33.3 mM MgCl2 or 0.1 M KCl (ionic strength 0.10) were 1.4 times larger than those described above. This suggests that Mg2+ does not inhibit Ca2+-binding of S-100 protein. The increase of KCl concentration from 0.1 to 0.2 M caused a decrease of the Ca2+-binding constants to ca. 50%. 相似文献
55.
Sequence and over-expression of subunits of adenosine triphosphate synthase in thermophilic bacterium PS3 总被引:8,自引:0,他引:8
S Ohta M Yohda M Ishizuka H Hirata T Hamamoto Y Otawara-Hamamoto K Matsuda Y Kagawa 《Biochimica et biophysica acta》1988,933(1):141-155
The primary structures of all the subunits of thermophilic ATP synthase were determined, and its alpha, beta and gamma subunits could be over-expressed in Escherichia coli, because these subunits were stable and reconstitutable. DNA of 7500 base pairs in length was found to contain a cluster of nine genes for subunits of ATP synthase. The order of their reading frames (size in base pairs) was: I(381): a(630): c(216): b(489): delta(537): alpha(1507): gamma(858): beta(1419): epsilon(396), I being a gene for a small hydrophobic, basic protein expressed in vitro. All the termini of TF0F1 subunits were confirmed by peptide sequencing. Large quantities of the overexpressed thermophilic alpha, beta and gamma subunits were prepared from the extract of E. coli, by a few purification steps. 相似文献
56.
Temperature effect of the photocyle of sensory rhodopsin (sR) was studied by nanosecond spectroscopy. Though the formation yield of sRM (sR370) was sharply decreased with temperature, those of sRK (sR680) and sRL were insensitive to temperature changes. These results show the existence of the branching process back to sR from sRL. The absorption maxima for sRK and sRL were 595 ± 5 and 555 ± 15 nm, respectively. 相似文献
57.
Y Wada T Matsuo I Katakuse T Suzuki T Azuma S Tsujino S Kishimoto H Matsuda A Hayashi 《Biochimica et biophysica acta》1986,873(2):316-319
A plasma prealbumin variant with a methionine-for-valine substitution at position 30 is closely associated with familial amyloidotic polyneuropathy (FAP) type I. Secondary ion mass spectrometry of the tryptic digest of a carrier's prealbumin could easily detect an abnormal peptide containing the substitution besides the normal peptide. This is a sensitive and reliable method for the diagnosis of FAP. 相似文献
58.
The effect of phospholipase C on two isozymes (alpha (+) and alpha forms) of rat brain (Na+ + K+)-ATPase and the temperature-dependence of their activities were investigated. Phospholipase C from Clostridium welchii inhibited the activities of the enzymes treated with and without pyrithiamin or N-ethylmaleimide, a preferential inhibitor of the alpha (+) form, but the extent of the inhibition was higher in the control enzyme than in the treated enzymes. The treatment of the (Na+ + K+)-ATPase with phospholipase C altered a ratio between high- and low-affinity components for ouabain inhibition. It also caused the similar change in a ratio between the alpha (+) and alpha forms of Na+-stimulated phosphorylation from [gamma-32P]ATP. These findings indicate that the alpha (+) form of rat brain (Na+ + K+)-ATPase is more sensitive to phospholipase C than the alpha form. Analysis of Arrhenius plots of the activities of the control and pyrithiamin-treated enzymes showed that there was a difference between the two enzymes in a break point. We suggest that two isozymes of rat brain (Na+ + K+)-ATPase differ in the interaction with phospholipids or in the lipid-environment. 相似文献
59.
Takeshi Murakami Hiroyuki Anzai Satoshi Imai Atsuyuki Satoh Kozo Nagaoka Charles J. Thompson 《Molecular & general genetics : MGG》1986,205(1):42-53
Summary We have isolated and studied the organization ofStreptomyces hygroscopicus genes responsible for the biosynthesis of the antibiotic herbicide bialaphos. Bialaphos production genes were cloned from
genomic DNA using a plasmid vector (pIJ702). Three plasmids were isolated which restored productivity toS. hygroscopicus mutants blocked at different steps of the biosynthetic pathway. Subcloning experiments using other nonproducing mutants showed
that four additional bialaphos production genes were also contained on these plasmids. A gene conferring resistance to bialaphos,
which was independently cloned using the plasmid vector pIJ61, and an antibiotic-sensitive host (S. lividans), was also linked to the production genes. Cosmids were isolated which defined the location of these genes in a 16 kb cluster. 相似文献
60.
Changes in lipoxygenase (LOX) activity were followed duringthe germination of rice seeds. The enzyme activity of 3-day-oldseedlings was 20 times higher than that of ungerminated seeds.Sixty per cent of the increased activity was found in shoots.The increase in LOX activity was mainly due to an increase inlipoxygenase-2 (LOX-2), a minor component in ungerminated seeds;this increase was inhibited by cycloheximide. LOX-2 was isolatedfrom the 3-day-old seedlings and compared for its enzymologicalproperties with rice lipoxygenase-3 (LOX-3), a major componentin ungerminated seeds. Both LOX-2 and LOX-3 were stable at pH5 to 8, but LOX-2 was more heatstable than LOX-3. Apparent Kmvalues of LOX-2 and LOX-3 for linoleic acid were 170 and 59µM, and those for linolenic acid were 5,300 and 88 µM,respectively. Both LOXs were inhibited by some metal ions andantioxidants. (Received February 5, 1986; Accepted May 9, 1986) 相似文献