The structure of nucleosome core particles as revealed by difference Raman spectroscopy.

Raman spectra have been observed of nucleosome core particles (I) prepared from chicken erythrocyte chromatin, its isolated 146 bp DNA (II), and its isolated histone octamer (H2A+H2B+H3+H4)2 (III). By examining the difference Raman spectra, (I)-(II), (I)-(III), and (I)-(II)-(III), several pieces of information have been obtained on the conformation of the DNA moiety, the conformation of the histone moiety, and the DNA-histone interaction in the nucleosome core particles. In the nucleosome core particles, about 15 bp (A.T rich) portions of the whole 146 bp DNA are considered to take an A-form conformation. These are considered to correspond to its bent portions which appear at intervals of 10 bp.     

Fetal hemoglobin variants in 80,000 Japanese neonates: high prevalence of Hb F Yamaguchi (AγT 80 Asp→Asn)

Summary A population-based screening of newborns for the structural variants of fetal hemoglobin was carried out in Osaka Prefecture, Japan, by isoelectric focusing of globin chains using dried blood on filter paper. Of 80,000 newborns, 18 had globin variants and 55 had globin variants. The incidence of globin variants (1/1,455) was much higher than that of globin variants (1/4,444). Structural studies were then carried out on the abnormal globins in 36 samples, and revealed that 25 of them were Hb F Yamaguchi (^AT 80 AspAsn). The prevalence of this variant in Japanese was estimated to be as high as one per 2,100.     

Biosynthesis of Bacillus licheniformis penicillinase in Escherichia coli and in Bacillus subtilis.

Modified prepenicillinase was accumulated in both Escherichia coli and Bacillus subtilis treated with globomycin. Although the inhibitions of processings of prepenicillinase and prolipoprotein by globomycin in E. coli are qualitatively similar, they differ in the degree of inhibition at given concentrations of globomycin. The processing of prepenicillinase proceeds much more rapidly in E. coli than in B. subtilis.     

Determination of molecular weight of membrane proteins by the use of low-angle laser light scattering combined with high-performance gel chromatography in the presence of a non-ionic surfactant

An assessment study was carried out to evaluate the performance of the low-angle laser light scattering technique combined with high-performance gel chromatography in the presence of a nonionic surfactant, octaethyleneglycol n-dodecyl ether, precision differential refractometry and ultraviolet photometry. It was found that the combined technique is highly promising as a method for the determination of the molecular weight of a membrane protein solubilized by the surfactant. For trial, molecular weights of the following membrane proteins of Escherichia coli, both solubilized in oligomeric forms, were measured; porin that forms the transmembrane diffusion pore in the outer membrane, and lambda-receptor protein that facilitates the diffusion of maltose-maltodextrins across the outer membrane. The result obtained indicates that both porin and lambda-receptor protein exist as trimers in the surfactant solution.     

Characterization of a new fetal hemoglobin variant, Hb F Izumi A gamma 6Glu replaced by Gly, by molecular secondary ion mass spectrometry

Molecular secondary ion mass spectrometry has characterized the structure of a new fetal hemoglobin variant, Hb F Izumi, without separation of peptides or amino acid analysis. First, the mass spectrum of a tryptic digest of the abnormal gamma globin revealed a decreased by 72 mass units in the molecular mass of peptide T-1,2, indicating the presence of a Glu leads to Gly substitution. Next, the analysis of the digest produced by the addition of staphylococcal protease, which specifically cleaves glutamyl peptide bonds, determined the site of substitution at 6th glutamic acid residue in peptide T-1,2 which contains two glutamic acid residues. Since this mass spectrometric approach provides digitalized data on peptide analysis, we call it 'digit printing'. The high sensitivity of this technique is especially promising for the analysis of molecular abnormality in various genetic disorders.     

Steady-state kinetics and spectral properties of Corynebacterium sarcosine oxidase

The overall reaction kinetics of Corynebacterium sarcosine oxidase were investigated and the reaction was shown to follow a ping-pong, bi-bi mechanism with two substrates, sarcosine and molecular oxygen. Sarcosine analogs, such as acetate, propionate and methoxyacetate, were competitive inhibitors of the reaction. Acetate caused characteristic alterations in optical and circular dichroic spectra, indicating that the microenvironment of the substrate-binding region of the enzyme increased in hydrophobicity on binding with the substrate analog. The dissociation constants of the analogs calculated from the spectral changes were in agreement with the kinetic inhibition constants. Inorganic metallic ions were also inhibitory. Of interest was the finding that the inhibition by Hg2+ was proportional to the square of its concentration, which suggests that at least two sulfhydryl groups are related to the catalytic activity of the enzyme.     

Nutritional requirements of Schistosoma japonicum eggs

Newly laid eggs of Schistosoma japonicum were cultured in a serum-free, chemically defined medium, RPMI 1640, which contained 20 amino acids, glutathione, 11 vitamins, and glucose in a balanced salt solution. The requirements for these components in the nutrition of the eggs was investigated by the deletion of single component from the medium. The following 14 amino acids were shown to be essential for the full development of the egg in the medium: L-arginine, L-cystine, glycine, L-histidine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-serine, L-threonine, L-tryptophan, L-tyrosine, and L-valine. Choline chloride was the essential vitamin. The omission of nicotinamide from the medium affected maturation adversely. Glucose was also required by the eggs. Minimal concentration of glucose for maturation of the eggs was 0.02 mM, but concentrations ranging from 0.16 to 20.00 mM gave better results while the concentration of the other elements of the medium were kept constant.     

A Highly Sensitive Enzyme Immunoassay for Mouse β Nerve Growth Factor

Abstract: A sensitive two-site enzyme immunoassay system for mouse β nerve growth factor (NGF) was developed, based on the sandwiching of the antigen between anti-mouse β NGF antibody IgG coated to a polystyrene tube and anti-mouse β NGF antibody Fab'-linked β- d -galactosidase (β- d -galactoside hydrolase, EC 3.2.1.23). This method has the following advantages: (a) the procedures are simple and rapid compared to bioassay or two-site radioimmunoassay; (b) antibody Fab'-β- d -galactosidase complex is more stable than ¹²⁵I-labeled antibody; (c) purified β NGF is detectable at a concentration as low as 10 pg/ml. Our enzyme immunoassay was used to examine the levels of NGF in some tissues of mice. The submaxillary gland contained a high concentration of NGF. However, other tissues, such as the heart, brain, and skeletal muscle, and serum did not contain detectable NGF. These results support recent findings by other investigators that NGF was not found in the organs/tissues other than the submaxillary gland of mice.     

Flavanol glucosides from rhubarb and Rhaphiolepis umbellata

Investigations of rhubarb and the bark of Rhaphiolepis umbellata led to the isolation of new flavan-3-ol glucosides. Their structures were elucidated on the basis of ¹H and ¹³C NMR analysis hydrolytic studies as (+)-catechin 5-O-β-d-glucopyranoside and (?)-catechin 7-O-β-d-glucopyranoside.     

Micelle formation of diacylglycerophosphocholines in organic solvents I. effects of the solvents on krafft points

Krafft points of diacylglycerophosphocholines (PC) were measured in alkanes-cyclohexane solutions by differential scanning calorimetry, and it was found that they were regularly increased following the increase in alkane content in the solutions and the chain length of the alkanes. From these results it was deduced that the mixing of PC with alkanes occurred in the gel state of the PC, but not in micelles at higher temperatures above the Krafft points. where micellar solutions are provided. The penetration of alkanes into gel state PC was found to be dominated by Langmuir type interaction, and the affinity of alkanes increases with increasing in chain lengths. Above the Krafft points, the micelle formation was confirmed by using the fluorescence probe technique.