Neural coding of speech sound in the telencephalic auditory area of the mynah bird

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     

Killer cells induced by stimulation with allogeneic tumor cells and subsequent culture with recombinant interleukin-2

Summary Peripheral blood lymphocytes were cultured for 5 days with allogeneic tumor cells (allogeneic mixed lymphocyte/tumor cell culture), and subsequently cultured with recombinant interleukin-2 for 12 days. These cultured cells were found to be cytotoxic to autologous tumor cells. Results of two-color analysis using monoclonal antibodies to cell markers showed that more than 80% of their cultured cells were CD3⁺ cells, and CD4⁺ cells showed a higher distribution than CD8⁺ cells. However, CD8⁺ cells had a much higher killing activity with autologous tumor than did CD4⁺ cells, when estimated by an elimination study using monoclonal antibodies to T cell phenotypes and complement. The cold-target inhibition test showed that the cytotoxicity of these cells for autologous tumor cells was inhibited by unlabeled autologous tumor cells but not by unlabeled stimulator cells. Furthermore, about 40% of the cytotoxicity was suppressed by blocking of HLA class I antigen with a monoclonal antibody on autologous tumor cells. Thus, cytotoxic activity of lymphocytes to autologous tumor restricted by target cell HLA class I antigen is possibly induced by allogeneic tumor-stimulation.     

Sensitive sandwich enzyme immunoassay of human growth hormone (hGH) in serum and urine using monoclonal antibody-coated polystyrene balls

A sensitive sandwich enzyme immunoassay for human growth hormone (hGH) using monoclonal antibody is described. A monoclonal anti-hGH IgG-coated polystyrene ball was incubated with hGH and subsequently with affinity-purified rabbit anti-hGH Fab'-horseradish peroxidase conjugate. Peroxidase activity bound to the polystyrene ball was assayed by fluorimetry using 3-(4-hydroxyphenyl) propionic acid as a substrate. The detection limits of hGH in serum and urine were 1.5 ng/l using 20 microliters of serum and 0.2 ng/l using 0.15 ml of urine, respectively. The specificity and assay precision were satisfactory. hGH levels in serum and urine determined by the present sandwich enzyme immunoassay using monoclonal anti-hGH IgG-coated polystyrene balls were well correlated to those determined by the previous sandwich enzyme immunoassay using rabbit anti-hGH IgG-coated polystyrene balls. Levels of hGH in urine collected as first morning voids from healthy subjects aged 19-28 yr were 6.4 +/- 3.2 (SD) ng/g creatinine. However, the present assay gave lower hGH levels than the previous assay. This was at least partly explained by the fact that hGH in urine was less efficiently bound to monoclonal anti-hGH IgG-polystyrene balls than standard hGH, while the binding of hGH in urine and standard hGH to rabbit anti-hGH IgG-coated polystyrene balls was equally efficient. In addition, gel filtration showed that 22K hGH, a major component, in urine was less efficiently bound to monoclonal anti-hGH IgG-coated polystyrene balls than standard 22K hGH. The nature of hGH in serum and urine remains to be investigated.     

The subunit structure of a major glutathione S-transferase form, MT, in rat testis. Evidence for a heterodimer consisting of subunits with different isoelectric points

A major glutathione S-transferase form (pI 5.7) in rat testis (MT) purified by S-hexyl-glutathione affinity chromatography, followed by chromatofocusing, showed two polypeptide of pI 6.7 (Yn1) and 6.0 (Yn2), having apparently the same molecular mass of 26 kDa on two-dimensional gel electrophoresis. Rechromatofocusing of the MT preparation after 4 M guanidine hydrochloride treatment revealed two additional protein peaks (pI 6.2 and 5.4). These were identified as the two homodimers consisting of the subunits of MT, Yn1Yn1 and Yn2Yn2, respectively. Furthermore, MT could be reconstituted from Yn1Yn1 and Yn2Yn2. These results indicate that MT is a heterodimer, Yn1Yn2, consisting of subunits with very similar molecular masses but different isoelectric points. The Yn1Yn1 form had glutathione S-transferase activities towards 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene. However, the Yn2Yn2 form had no activity towards any of the substrates examined. N-terminal amino acid sequences of subunits Yn1 and Yn2 revealed differences at two positions in the first 20 residues; the amino acid compositions of these subunits were also similar but not identical, indicating that these two subunits are different in the primary structure. Subunits Yn1 and Yn2 are immunologically related to each other and also to subunits 3 (Yb1) and 4 (Yb2) but they are not identical. These four subunits also showed a high degree of similarity in N-terminal amino acid sequences. Subunits Yn1 and Yn2 seem to belong to the rat GST 3-4 family or class mu. Subunits Yn1 and 4 can make a heterodimer, which is detectable not only in rat testis, but also in the heart, kidney and lung. The Yn1Yn1 form was not detected in the testis, but is present in rat brain [Tsuchida et al. (1987) Eur. J. Biochem. 170, 159-164]. The Yn2Yn2 form seemed to differ from GST 5-5 and may be a new form of rat glutathione S-transferase.     

Localization of the regulatory subunit of cAMP-dependent protein kinase in Saccharomyces cerevisiae

The subcellular distribution of the regulatory subunit of cAMP-dependent protein kinase in Saccharomyces cerevisiae cells was determined by subcellular fractionation and indirect immunofluorescence microscopy using the bcy1 mutant deficient in the regulatory subunit as control. The regulatory subunit of cAMP-dependent protein kinase showing cAMP-binding activity was identified as a single protein of 50 kDa by photoaffinity labeling and immunoblotting. The regulatory subunit was concentrated in a nuclear fraction in addition to a cytoplasmic fraction. By comparison of the regulatory subunit distribution with the DNA localization, the area detected by the indirect immunofluorescence was identified as the nucleus.     

Movement of water in conjunction with plant movement visualized by NMR imaging

The water distribution in the pulvinus of Mimosa can be visualized by an NMR imaging technique. After stimulation of a Mimosa plant, water in the lower half of the main pulvinus disappeared, the water previously contained in this area seeming to be transferred to the upper half of the main pulvinus. Movement of the water in conjunction with Mimosa movement was visualized sequentially by a non-invasive NMR imaging procedure.     

The effect of inosine on the post ischemic heart as bio-energy recovering factor in 31P-MRS

Perfused guinea-pig hearts, which were analyzed by 31P-MRS, were subjected to 30 and 60 minute ischemia and reperfused using two perfusates, one containing 200 microM inosine, and the other without inosine. After 4 hour reperfusion with inosine, ATP levels increased to 95.5% of preischemic value (30 minute ischemia) and 76.2% (60 minute ischemia). However, after 4 hour reperfusion without inosine, ATP levels increased only to 72.2% (30 minute ischemia) and to 48.2% (60 minute ischemia). In 60 minute ischemic hearts reperfused with inosine, left ventricular maximal positive dp/dt (LV dp/dt) was improved significantly to 82.4% after 6 hour reperfusion in contrast to hearts reperfused without inosine (43.1%). Administration of inosine was very useful for increasing myocardial gross energy product and improving cardiac performance.     

The major isozyme of rat cardiac glutathione transferases. Its correspondence to hepatic transferase X

A major isozyme of rat heart glutathione transferase was purified to homogeneity by Sephadex G-200 gel filtration, ammonium sulfate precipitation, CM-cellulose chromatography and affinity chromatography on S-hexylglutathione-linked Sepharose 6B. The purified isozyme was a dimer with an apparent relative molecular mass of 50 000 composed of two Yb-size subunits (Mr = 26 500). The isozyme is immunologically related to rat liver glutathione transferase X and 3-3, especially closely to transferase X, and no immunological cross-reactivity with subunits 1 and 2 of hepatic glutathione transferases was observed. The isoelectric point (pI = 6.9) of the isozyme was identical with and the substrate specificity was very similar to transferase X. Thus, the cardiac near-neutral isozyme is considered to be identical to glutathione transferase X recognized in rat liver. The amount of this near-neutral isozyme estimated to be present in heart tissue is 70 micrograms/g. The isozyme has relatively high activities towards alpha, beta-unsaturated carbonyl compounds such as trans-4-phenyl-3-buten-2-one and trans-4-hydroxynon-2-enal. The latter is a cytotoxic product resulting from lipid peroxidation of polyunsaturated fatty acids, and the cardiac isozyme may play a physiologically significant role with glutathione conjugation of this compound. In addition to the near-neutral isozyme, acidic forms with isoelectric points of 4.9, 5.2 and 5.5 were partially purified; some of them are considered to consist of subunits immunologically related to transferase X.     

Recessive Nonsense Suppressors in SACCHAROMYCES CEREVISIAE : Action Spectra, Complementation Groups and Map Positions

Three genes SUP111, SUP112 and SUP113 of Saccharomyces cerevisiae have been identified that can mutate to give recessive omnipotent nonsense suppressors. Alleles of these loci can also act as allosuppressors; that is, different phenotypes, due apparently to different efficiencies of suppression, can result from different alleles at a given locus. The SUP111, SUP112 and SUP113 loci map to the right arms of chromosomes VIII, VII and XIII, respectively.