X-ray equatorial diffraction studies on the cross-sectional structure of Salmonella flagella

X-ray diffraction studies have been made on the cross-sectional structure of the normal Salmonella flagella. Two approaches have been made: one based upon small-angle equatorial scatterings (2θ 3°) and the other upon moderate-angle angle equatorial diffractions (3° 2θ 10°).Analysis of small-angle scattering data gives the radius of gyration of the flagella as 68 Å. Cylindrically averaged electron density of the cross-section of the flagella is obtained by means of the Fourier-Bessel transformation method. The average radius of the flagella is about 65 Å.In the investigation of the moderate-angle diffraction pattern, validity is examined of the model that a flagellum consits annularly arranged strands, of which each has a cylindrically symmetric structure. Features of the pattern observed in the range of 3° < 2θ < 10° can be interpreted fairly well by this model. Average radii of the flagella obtained for the 11 and 13 strands models are close to that obtained by the analysis of the small-angle scattering data.     

Role of microstructure of nerve impulse train in relation to transmission of neuronal activity and coding mechanism of neural information

Input-output relation were of giant neurons of a marine mollusc, Onchidium verruculatum, and a computer-simulated neuron investigated in terms of microstructure of nerve impulse train. The microstructure of input impulse train, the size of a unitary EPSP, and the extent of spontaneous firing activity of a single neuron had an important influence upon the effective summation of arriving synaptic inputs, the elicitation of output spikes, and intervals between succeeding output spikes. The neuron responded differently to respective input trains with different time structures, i.e. it discriminated input time pattern to various degrees. The manner in discrimination of input time pattern was dependent on the size of the unitary EPSP and the extent of the spontaneous firing activity, if it had. Some discussions were made with regard to possible coding systems of neural signal, assuming a frequency code and/or a pattern code.     

Clinical Use of a New Mitral Disc Valve

A disc valve of new design was used successfully for the replacement of the mitral valve in patients with rheumatic mitral valve disease. This valve would appear to have the following advantages over the mitral ball valve prosthesis:• Lower left atrial pressure after replacement.• Elimination of the hazard of left ventricular outflow tract obstruction with mitral valve replacement.• Decreased incidence of thromboembolization.• Abolition of possibility of ventricular septal irritation.Despite the better outlook for this valve compared with the ball valve for mitral valve substitution, the mitral valve should always be repaired whenever feasible. Repair is possible in the majority of patients.     

Establishment of five human myeloma cell lines

Summary Five human myeloma cell lines, KMM-1, KMS-5, KMS-11, KMS-12- PE, and KMS-12-BM, have been established at Kawasaki Medical School since 1980. As the KMS-12-PE and KMS-12-BM lines were obtained from the same patient, these five cell lines have been derived from four patients with multiple myeloma. The five myeloma cell lines are stably growing at present in RPMI 1640 medium supplemented with 10% fetal bovine serum. They can also grow in a defined culture medium without serum. That these cell lines were, human myeloma cells was confirmed by the following findings. Ultranstructually, all five cell lines showed features characteristic of plasma cells. KMM-1 and KMS-11 cells secreted lambda and kappa chains into the culture medium, respectively, but the other cell lines produced no immunoglobulins. KMM-1 expressed cytoplasmic lambda antigen, KMS-5 showed cytoplasmic delta, and KMS-11 expressed surface kappa, whereas KMS-12-PE and KMS-12-BM cells showed no surface or cytoplasmic immunoglobulins. Regarding reaction with a monoclonal plasma cell antibody (PCA-1), four of the five lines were positive, the exception being KMS-5. Another monoclonal antibody (CD38), which also recognizes plasma cells, reponded to KMM-1, KMS-12-PE, and KSM-12-BM. KMS-5 cells expressed acute lymphoblastic leukemia antigens (CALLA). These data suggest that such lines as KMM-1, KMS-11, KMS-12-PE, and KMS-12-BM represent later stages of B-cell differentiation, and that KMS-5 represents a relatively early stage of B-cell differentiation. All the cell lines lacked Epstein-Barr virus nuclear antigen, showed abnormal karyotypes of human origin, and differed from each other in the isozyme patterns examined. Only KMS-5 was tumorigenic when transplanted subcutaneously into nude mice.     

Identification of membrane anchoring site of human renal dipeptidase and construction and expression of a cDNA for its secretory form

The chemical properties of human renal dipeptidase (hrDP) purified from the membrane fraction of kidney have been characterized. When treated with phosphatidylinositol-specific phospholipase C, hrDP was released from renal membrane fractions. After digestion with trypsin, carboxyl-terminal peptide was isolated employing anhydrotrypsin-agarose column chromatography and reversed-phase high performance liquid chromatography. The amino acid sequence of the peptide was identified at positions 363-369 in the primary structure deduced from the cDNA sequence (Adachi, H., Tawaragi, Y., Inuzuka, C., Kubota, I., Tsujimoto, M., Nishihara, T., And Nakazato, H. (1990) J. Biol. Chem. 265, 3992-3995). Further examination of the chemical composion of the peptide showed that it contained, respectively, 2, 1, 5, 1, and 1 mol of ethanolamine, glucosamine, mannose, inositol, and phosphate in addition to amino acids. These results suggest that the mature hrDP molecule lacks the carboxyl-terminal hydrophobic peptide extension predicted from the cDNA sequence and is anchored at Ser369 via glycosylphosphatidylinositol to the membrane. To characterize further the action of the enzyme, we have established expression systems for both secretory and membrane anchored forms of hrDP using COS-1 cells and found that both recombinant forms were as active as natural enzyme. Our expression system made it possible to prepare large amounts of soluble enzyme, and will contribute toward elucidation of the physiological roles of the enzyme.     

The Large Isoform of Myelin-Associated Glycoprotein Is Scarcely Expressed in the Quaking Mouse Brain

Two polypeptide isoforms of myelin-associated glycoprotein (MAG) with molecular masses of 72 and 67 kDa are produced by alternative splicing of the exon 12 portion. Our previous work has demonstrated that in the quaking mouse brain this alternative splicing is lacking and that the mRNA coding the large MAG isoform (L-MAG) is scarcely expressed, whereas that of small MAG isoform (S-MAG) is overexpressed. In the present study, we prepared antisera specific to the S-MAG and L-MAG amino acid residues, respectively. Immunoblots showed that the L-MAG band was scarcely detectable in the quaking mouse brain, whereas the S-MAG band had an apparently higher molecular mass than in the normal control. Our immunohistochemical study also showed that L-MAG was scarcely stained in the quaking mouse brain. These results seemed to reflect a reduction in content of L-MAG mRNA and abnormal glycosylation in the quaking mouse brain.     

Effects of a New Calcium Channel Blocker, KB-2796, on Protein Synthesis of the CA1 Pyramidal Cell and Delayed Neuronal Death Following Transient Forebrain Ischemia

The effects of a new calcium channel blocker, 1-[bis(4-fluorophenyl)methyl]-4-(2,3,4-trimethoxybenzyl)-piperazine dihydrochloride (KB-2796), on delayed neuronal death (DND) in the hippocampus were examined in gerbils in comparison with those of pentobarbital and flunarizine. The neuronal density in the hippocampal CA1 subfield was counted on the seventh day of recirculation following 5 min of bilateral carotid occlusion, and protein biosynthesis in the brain was also determined at 1, 2, 4, 24, and 72 h following occlusion. The drugs were intraperitoneally administered after recirculation. KB-2796 (10 mg/kg) significantly prevented DND in the CA1 subfield. Pentobarbital (40 mg/kg), but not flunarizine (3 and 10 mg/kg), inhibited DND. Protein synthetic activity in the CA1 subfield was reduced by ischemia and the reduction was not restored even at 72 h after recirculation. KB-2796 did not ameliorate the reduction of protein synthesis in the CA1 subfield by 24 h after recirculation, but in one of three animals restoration of protein synthesis was observed at 72 h of recirculation. Pentobarbital also restored the reduced protein synthesis in two of three animals at 72 h. These results suggest that calcium influx into neurons participates in the pathogenesis of DND, and also that KB-2796 might prevent both morphological and functional cell damage in CA1 neurons induced by transient ischemia.