Role of the carboxy-terminal region of the GluR epsilon2 subunit in synaptic localization of the NMDA receptor channel

The synaptic localization of the N-methyl-D-aspartate (NMDA) type glutamate receptor (GluR) channel is a prerequisite for synaptic plasticity in the brain. We generated mutant mice carrying the carboxy-terminal truncated GluR epsilon2 subunit of the NMDA receptor channel. The mutant mice died neonatally and failed to form barrelette structures in the brainstem. The mutation greatly decreased the NMDA receptor-mediated component of hippocampal excitatory postsynaptic potentials and punctate immunofluorescent labelings of GluR epsilon2 protein in the neuropil regions, while GluR epsilon2 protein expression was comparable. Immunostaining of cultured cerebral neurons showed the reduced punctate staining of the truncated GluR epsilon2 protein at synapses. These results suggest that the carboxy-terminal region of the GluRepsilon2 subunit is important for efficient clustering and synaptic localization of the NMDA receptor channel.     

Characterization of two restriction endonucleases, SenPT14bI and SenPT16I, in standard phage-type strains of Salmonella enteritidis

Two restriction endonucleases (ENases) were found by screening 38 standard phage strains of Salmonella (S.) Enteritidis. An isoschizomer of SacII ENase that recognizes the sequence 5'-CCGC/GG-3' was identified in S. Enteritidis PT14b, and an isoschizomer of XmaIII ENase (5'-C/GGCCG-3') was found in S. Enteritidis PT16. It is of special interest that the recognition specificities of all known ENases in Salmonella, including those of the S. Enteritidis ENases, are very similar to each other.     

Growth of InxGa(1−x)N compound semiconductors and high-power InGaN/AlGaN double heterostructure violet-light-emitting diodes

In_xGa(_1−x)N films were grown on GaN films with an indium mole fraction x up to X = 0.33 at temperatures between 720°C and 850°C. The growth rate of InGaN films had to be decreased sharply to obtain high-quality InGan films when the growth temperature was decreased. Band-gap energies between 2.67 eV and 3.40 eV obtained by room-temperature photoluminescence measurements fit quite well to parabolic forms previously obtained by Osamura et al. on the indium mole fraction x assuming that the band-gap energies for GaN and InN are 3.40 and 1.95 eV, respectively. High-power InGaN/AlGaN double-heterostructure violet-light-emitting diodes were fabricated. The typical output power was 1000 μW and the external quantum efficiency was as high as 1.5% at a forward current of 20 mA at room temperature. The peak wavelength and the full width at half-maximum of the electroluminescence were 380 nm and 17 nm, respectively.     

Dynamic properties of 1.3 μm semi-insulating-BHlight-emission-and-detection (LEAD)-diode module for subscriber TCMtransmission systems

The dynamic properties of a 1.3 μm light-emission-and-detection (LEAD)-diode module that has a high mesa semi-insulating buried heterostructure (SI-BH) to reduce the capacitance of the chip (0.6-0.8 pF) are described. A modulation bandwidth of 12 GHz in laser diode (LD) operation, and detection bandwidth of ~1.9 GHz in photodetector (PD) operation are achieved using a chip and a module, respectively. In bit error rate (BER) performance at 30 Mbit/s, a receiver sensitivity (BER=10^-8) of -37.4 dBm is confirmed, and a switching time of under 1 μs from LD to PD operation is estimated using a circuit simulator     

Influence of the renal sympathetic nerves on renal renin and angiotensinogen gene expression in spontaneously hypertensive rats during development

OBJECTIVE: To investigate the influence of renal sympathetic denervation on renin and angiotensinogen gene expression in the kidney during growth and the development of hypertension in spontaneously hypertensive rats (SHR). Comparative studies were undertaken in age-matched normotensive Wistar rats. DESIGN: Four-week-old SHR and Wistar rats were subjected to either denervation of the left kidney or sham operation. At age 5, 7 or 9 weeks the rats were lightly anaesthetized, carotid blood pressure was measured, a blood sample was taken and both kidneys were removed. METHOD: Plasma renin activity was measured by radioimmunoassay, and renal renin and angiotensinogen messenger RNA (mRNA) levels were measured by Northern blot hybridization followed by densitometric analysis. RESULTS: In 5- and 7-week-old SHR the renin mRNA level in the left kidney was significantly suppressed compared with that in the sham-operated right kidney and with the level in 9-week-old SHR. The renal renin mRNA level in sham-operated SHR decreased significantly with increasing age, whereas in the Wistar rats the renal renin mRNA level did not change at any age and was not affected by renal denervation. The renal angiotensinogen mRNA level gradually increased with age in both rat strains and was not affected by denervation, but much higher levels were attained in the Wistar rats than in the SHR. CONCLUSION: Renal angiotensinogen gene expression was depressed in the SHR, with little evidence of neural regulation at any age in the SHR or the Wistar rats. However, in the SHR the renal sympathetic nerves elevated renal renin gene expression in the prehypertensive stage, but their influence decreased as hypertension developed.     

An effect of sudden circumferential strain on the laminar boundary layer on a rotating cylinder in an axial flow

Summary The laminar boundary layer which develops on a rotating thin cylinder fitted with an aft-section rotating with an angular velocity different from that of a fore-section is examined numerically. This problem concerns a relaxation process of the boundary layer subjected to a sudden circumferential rate of strain. Two methods are adopted: one is to regard the flow on the aft-cylinder as perturbations of that on the fore-section, and the other is to approximate the discontinuous change in the angular velocity by the cumulative normal distribution function. It is shown that the flow fields are largely influenced by the degree of favorable pressure gradient produced in the boundary layer. Especially, in case of flow passing onto the aft-section with a smaller angular velocity, adverse pressure gradient is induced immediately after the junction between two cylinders, and when the degree of the discontinuity is increased, flow separation can be provoken.With 11 Figures     

Thiol-mediated redox regulation of apoptosis. Possible roles of cellular thiols other than glutathione in T cell apoptosis

Thiol redox status modulates various aspects of cellular function. We demonstrate that oxidation of cellular sulfhydryl (SH) groups induces apoptosis. In Jurkat T cells and human PBL blasts, the fraction of apoptotic nuclei increased after treatment with an SH-specific oxidant, diamide. Analysis of DNA fragmentation and nuclear morphology also indicated that SH oxidation could induce apoptosis. In the apoptosis induced by SH oxidation, the decrease of cellular glutathione was transient and the increase of glutathione disulfide was observed only after apoptotic changes had occurred. Depletion of cellular glutathione with buthionine sulfoximine failed to induce apoptosis, despite a marked decrease of cellular glutathione, which was greater than that observed in apoptosis induced by diamide. Thus, the changes of cellular glutathione or glutathione disulfide may not be the major cause of apoptosis induced by diamide. Intracellular adult T cell leukemia-derived factor/human thioredoxin, another thiol-related antioxidant protein, was oxidized by incubation with diamide. These results suggest that thiol redox status is one of the key factors of the apoptotic pathway in which thiols other than glutathione may play even more critical roles.     

STOICHIOMETRIC RELATIONS OF CHEMICAL OSCILLATION SYSTEMS AND STOICHIOMETRIC NUMBER THEORY

The stoichiometry of chemical oscillation systems, especially that of the Oregonator proposed by Field and Noyes (1974), is discussed with use of the generalized stoichiometric number theory by Horiuti and Nakamura (1957). The independent stoichiometric equations derived by Noyes (1976) are shown to correspond to Horiuti and Nakamura's reaction routes, each of which was expressed in terms of a set of stoichiometric numbers. It is found that the relations derived by Noyes are partly incorrect.     

Alpha 2-macroglobulin of rabbits inhibits the habutobin activity

We have investigated whether alpha 2-macroglobulin (alpha 2M) of rabbits inhibits the activity of habutobin, a thrombin-like enzyme from Trimeresurus flavoviridis venom. Rabbit alpha 2M was purified with ultracentrifugation, gel filtration on Sepharose 6B and ion exchange chromatography on DEAE-Sephacel. Inhibitory effects of rabbit alpha 2M on habutobin was determined by the fibrin forming activity, digestion of A alpha chain of fibrinogen, and the release of fibrinopeptide A from fibrinogen. As a results, purified alpha 2M showed a single band with high molecular weight, around 800,000 mol. wt by means of polyacrylamide gel electrophoresis using PhastSystem. Besides inhibiting amidolytic and caseinolytic activity of porcine trypsin, it has inhibited the activity of habutobin: that is, in the presence of rabbit alpha 2M, fibrin forming activity of habutobin was decreased and habutobin-induced digestion of A alpha chain was inhibited. In addition, rabbit alpha 2M reduced habutobin-induced release of fibrinopeptide A from rabbit fibrinogen.