Growth of a human yolk sac tumor cell line with yolk sac-derived functions in selenium-supplemented chemically defined synthetic medium

Summary A human yolk sac tumor cell line, TG1, which was established from a testicular yolk sac tumor, was found to replicate continuously in a chemically defined medium supplemented with Na₂SeO₃ (ISRPMI). TG1 produced several plasma proteins and growth factors: albumin, alpha-fetoprotein (AFP), ferritin, carcinoembryonic antigen, beta-2-microglobulin, polyamine, neuron specific enolase, tissue polypeptide antigen, transferrin (Tf), epidermal growth factor, and platelet derived growth factor. By analysis of lectin (LcHA)-affinity electrophoresis, to examine the microheterogeneity of carbohydrate chains of synthetic glycoproteins, TG1 cells cultured with ISRPMI produced only LcHA reactive Tf and AFP based on core fucose attached to asparagine-linkedN-acetylglucosamine residues instead of LcHA-nonreactive Tf and AFP produced by TG1 cells cultured with fetal bovine serum (FBS)-containing medium.α1-6 Fucosyltransferase activity was significantly greater in the TG1 cells cultured with ISRPMI (39.9±1.5 pmol · h⁻¹ · mg⁻¹ protein) than cultured with FBS-containing media (18.2±1.2 pmol · h⁻¹ · mg⁻¹ protein). These results have indicated that the selective increase ofα1-6 fucosyltransferase occurred when the cells were cultured with the FBS-free synthetic media.     

Determination of eperisone in human plasma by gas chromatography—mass spectrometry

A gas chromatographic—mass spectrometric method was developed to determine eperisone hydrochloride, 4′-ethyl-2-methyl-3-piperidinopropiophenone hydrochloride, in human plasma over the concentration range 0.2–40 ng/ml. Excellent sensitivity was achieved by selection of a favorable fragment ion, m/z 98, of eperisone and reduction of heat decomposition of eperisone by using a splitless injector and a shortened capillary column. The method described here allows the determination of plasma concentrations as low as 0.2 ng/ml, the concentration attained 6 h after a single oral administration of 50 mg. At eperisone hydrochloride concentrations higher than 0.5 ng/ml, the mean inter-day variation of accuracy of the assay was less than 12%.     

Fitness and its components in Drosophila melanogaster

Fitness and its components in Drosophila melanogaster were estimated under the homozygous condition. All of these parameters, except for egg-to-adult viability and female fecundity, were measured under interspecific competition with D. hydei. The following results were obtained: (1) Significant genetic variation was detected in fitness, productivity, adult viability, total egg-to-adult viability and female fecundity. (2) Significant correlation was obtained between fitness and productivity (rp = 0.792 for phenotypic correlation, rg = 0.945 for genotypic correlation), between fitness and total egg-to-adult viability (rp = 0.355, rg = 0.395), and between fitness and female fecundity (rp = 0.451, rg = 0.511). (3) There was no significant correlation between total egg-to-adult viability and fecundity (rp = -0.046). The biological implications of the interrelationship between fitness and its components are discussed.     

An epidemic of echovirus 18 in 1988 in Japan--high association with clinical manifestation of exanthem. A report of the National Epidemiological Surveillance of Infectious Agents in Japan

Laboratory reports of isolation of echovirus serotype 18 (E18) slightly increased in the summer of 1987 followed by a sharp increase with a peak in July, 1988. A total of 1,094 isolations were reported during these two years from 39 laboratories participating in the National Epidemiological Surveillance of Infectious Agents in Japan. When compared with the previous E18 outbreaks, a higher proportion of children at two years of age or under (58.3%) and a much higher incidence of exanthem (46.4%) were remarkable. Meningitis-associated isolations were reported in 30.6%, less than half of the percentage of the previous epidemic.     

Cytological studies on the mosaic silkworms induced by low temperature treatment

Mosaic silkworms were induced when the hybrid eggs of two strains with different egg color and larval markings were exposed to low temperature. Cytological studies were conducted to find out the relation between mosaic larval pattern and ploidy in reproductive cells along with demonstration of chromosomes in the mosaic embryos. — Mosaic eggs eith the characters of both the father and the hybrid were two types, one with large serosa nuclei (LN-mosaic) and the other with small serosa nuclei (SN-mosaic). The cytological studies demonstrated that LN-mosaic individuals were 2n/4n, while SN-mosaic ones were n/2n. In both types of silkworms, cell ploidy level in nuclei of synkaryon origin was two times that of androgenic ones. — From the results obtained in the present studies as well as in the previous studies, a possible mechanism of induction of mosaicism in silkworms by cold shock is contemplated.     

Kinetic analysis of the acid-alkaline conversion of horseradish peroxidases.

The nature of the acid-alkaline conversion of horseradish peroxidases was studied by measuring four rate constants in reactions, E + H+ (k1) in equilibrium (k2) EH+ and E + H2O (k3) in equilibrium (k4) EH+ + OH-, where EH+ and E denote the acid and alkaline forms of the enzymes. The values of k1, (k2 + k3), and k4 were obtained by measuring the relaxation rates of the acid leads to alkaline and alkaline leads to acid conversions by means of th pH jump method with a stopped-flow apparatus. The value of k3 could also be obtained by measuring the rate of reactions between hydrogen peroxide and peroxidases at alkaline pH. The measurements were conducted with four peroxidases having different pKa values: peroxidase A )pKa = 9.3), peroxidase C (pKa = 11.1), diacetyldeuteroperoxidase A (pKa = 7.7), and diacetyldeuteroperoxidase C (pKa = 9.1). The value of k1 was about 10(10) M-1 s-1 in the reaction of the four enzymes while k4 was quite different between the enzymes. The pKa was determined by k3 and k4 for the natural peroxidases and by k1 and k2 for the diacetyldeuteroperoxidases. The mechanism of the acid-alkaline conversion was discussed in comparison with that of metmyoglobin.     

Plant growth-promoting activities of alkoxycarbonylisoureas in relation to their chemical structures

A number of alkoxycarbonylisourea derivatives were synthesized and their plant growth-promoting activities examined by the rice (Oryza sativa) seedling test. Isourea compounds with an appropriate substituent such as a halogen atom or a methyl, ethyl or methoxy group at the para-position on a benzene ring in 1-alkoxycarbonyl-2-alkyl-3-phenylcarbamoylisoureas promoted the growth of rice seedlings and acted as a highly active gibberellic acid-synergist when used in combination with gibberellic acid. The common structural requirements of isourea derivatives applied well for a growth promoter and a gibberellic acid-synergist.     

Hereditary respiration deficiency in Saccharomycodes ludwigii

Saccharomycodes ludwigii, supposed to be petite-negative, gave rise to respiration-deficient mutants when acriflavine and ultraviolet irradiation, respectively, were applied to this yeast, strain IFO 1194. The frequency of such mutants was very low as compared with that in Saccharomyces cerevisiae and other petite-positive yeasts. Cytochrome composition was characterized by spectrophotometry at the temperature of liquid nitrogen. The respiratory mutants examined contained cytochrome c unaltered in quality and quantity. Cytochrome b was often present only in small amounts though never absent, while cytochrome a+a₃ was either present or absent. The respiratory mutants could form zygotes after conjugation with a wild-type culture of opposite mating type ( vs. a). The hybridization and segregation analysis of spore tetrads showed the inheritance of respiratory mutant character to be either Mendelian or non-Mendelian and similar to that of pet (nuclear) and rho^- (cytoplasmic) mutants, respectively, in Saccharomyces cerevisiae.     

Effects of 2,4-substituents of deuteroheme upon the stability of the oxy-form and compound I of horseradish peoxidases.

The stability of oxyperoxidases increased in the order meso- < proto < chlorocruoro- < diacetylperoxidases, which was an increasing order of electron-withdrawing capacities of 2,4-substituents of deuteroheme and the ratio of Δlogk₁toΔpK₃ was approximately 0.6 in the two series of isoenzyme preparations, horseradish peroxidases A and (B + C), where k₁andpK₃ represent a rate constant for conversion from an oxyperoxidase to the ferric enzyme and a measure of basicity of pyrrole nitrogen of the substituted deuterohemes, respectively. Deutero-oxyperoxidases A and (B + C) were definitely more stable than expected from the above linear relationship. The stability of peroxidase Compound I also varied with the 2,4-substituents, but it did not necessarily correlate with electron-withdrawing capacities of the substituents. Natural peroxidases formed relatively stable Compound I in both series of the isoenzymes. From these results it was concluded that the stability of oxyperoxidases was affected by the electron density at the iron atom of the enzyme while steric factors might be involved in stabilizing Compound I.