Primary structure of mitochondrial glutamic oxaloacetic transaminase from rat liver: Comparison with that of the pig heart isozyme

The complete amino acid sequence of the mitochondrial glutamic oxaloacetic transaminase isozyme from rat liver is presented. The sequence contained 401 amino acid residues, 10 of which are methionine. Cyanogen bromide cleavage of mitochondrial glutamic oxaloacetic transaminase produced 12 peptides, one of which contained an internal homoserine residue resulting from incomplete cleavage by cyanogen bromide. The calculated molecular weight was 44,358. The sequence showed 94% homology with that of the corresponding isozyme from pig heart. These findings support the conclusion that the rate of evolution of the mitochondrial isozymes is lower than that of their cytosolic isozymes.     

The genetic map of transfer RNA genes of yeast mitochondria: Correction and extension

Summary Ninety five rho^- mitochondrial DNA's of Saccharomyces cerevisiae were compared for their deletion structure by means of 15 genetic markers and 22 tRNA genes. The patterns of co-deletion and coretention of different tRNA genes allowed us to determine their positions with respect to each other. The deduced order of tRNA genes was consistent with the order of the genetic markers established by independent genetic approaches. Our previously proposed mitochondrial tRNA gene map has been revised and extended. Transfer RNA genes, corresponding to all 20 aminoacids, and two isoacceptor tRNA genes were localized. The possible position of each tRNA gene has been indicated on the physical map of mitochondrial DNA. Seventeen tRNA genes are carried by a narrow region representing less than 20% of the wild type genome.Abbreviations tRNA transfer RNA - mRNA messenger RNA - rRNA ribosomal RNA - mitDNA mitochondrial DNA - nucDNA nuclear DNA - EDTA ethylenediaminetetraacetate - C, E, O_I, O_II and P drug resistance genetic loci - Rib I, Rib III O_I, O_II and P_I respectively. The three letter symbols for amino acids (ala, cys, etc...) designate tRNA genes corresponding to each amino acid Formerly Fondation Curie, Institut du Radium     

Two isoaccepting seryl tRNAs coded by separate mitochondrial genes in yeast

Summary In S. cerevisiae four isoacceptor mitochondrial tRNAs for serine have been separated by reversed phase chromatography. At least two of these species are products of different genes. In this work the deletion mapping technique has been used to locate two genes for tRNA^ser. The gene for tRNA^ser previously localized in the oli I region of the mitochondrial genome has been found to code for tRNA _ser ² , and another gene coding for tRNA _ser ¹ has been detected in the region where most of other tRNA genes are found. Results of fine mapping experiments allowed to localize this gene in the proximity of the gene for tRNA^arg.     

Regulation of the production of the agglutination substances responsible for sexual agglutination in Saccharomyces cerevisiae: Changes associated with conjugation and temperature shift

Summary Isolated zygotes showed self-agglutination caused by the sex-specific glycoproteins, the agglutination substances responsible for sexual agglutination. The agglutination substances of both a and mating types were detected in the extracts obtained by the autoclave method from zygotes. Although the first diploid daughter cells from zygotes showed self-agglutinability, the self-agglutinability decreased gradually in the successive diploid daughter cells. The self-agglutination in diploid cells was also brought about by the complementary binding of the sex-specific agglutination substances of opposite mating types.The constitutive sexual agglutinability in a and cells was lost with concomitant loss of the agglutination substances in both cell wall and cytoplasmic fractions when cultured at a temperature higher than 35°C.The repression of the production of the agglutination substances was reversed by the opposite mating type pheromones even at the repressive temperature, 36°C, associated with the appearance of sexual agglutinability. The sex pheromones, a substance-I and substance-I, and the binding substance for substance-I were produced even at 36°C, repressive for the production of the agglutination substances.     

Studies on the cell wall of Chlorella II. Mode of increase of glucosamine in the cell wall during the synchronous growth of Chlorella ellipsoidea

The dry weight and glucosamine content of the alkali-insoluble"rigid wall" of Chlorella ellipsoidea were measured in synchronouslygrowing and dividing cells. The content of glucosamine, the major component of the rigidwall, was measured by the Elson-Morgan and the ninhydrin reactions.The results revealed, in agreement with previous observations,that the amount of the rigid wall, measured in terms of wholedry weight or glucosamine content, remains almost constant duringthe growing phase and increases only in the reproduction phase. (Received February 19, 1979; )     

Developmental changes in soluble proteins during the early development of Dictyostelium discoideum

Changes in the pattern of soluble proteins that accumulatedat the growth phase, interphase and late-aggregation phase ofthe cellular slime mold Dictyostelium discoideum were studiedby two-dimensional polyacrylamide gel electrophoresis. Amongthe 300 proteins detected during the early development, themost soluble do not change during the growth and aggregationphases, but about 90 proteins show changes in their relativeintensities on staining. During the transition from growth tothe interphase, the predominant changes were the disappearanceof 16 spots, the decrease in 30 spots, the appearance of 13new spots, and the increase in 14 spots. In contrast, from theinterphase to the late-aggregation phase, there were remarkableprogressive increases in 13 spots, an overall increase in 6spots, a decrease in 16 spots, the appearance of 8 new spotsand the disappearance of 4 spots. (Received July 13, 1979; )     

Comparative potencies of botulinum toxin for infant and adult mice

Culture fluids of 4 type A, 6 type B, and 1 type EClostridium botulinum strains were compared for their toxicities in 9–11-day-old (infant) and adult mice. In intraperitoneal challenges, most toxins were about equally potent for infants and adults; the exceptions were 4 type B preparations, which were 500 to 5,000 times more lethal for infants. In orogastric challenges, samples were 10 to >15,000 times more toxic for infants, and the previously mentioned type B toxins constituted a group having the highest relative toxicity for infants.     

Fungal contamination and mycotoxin-producing potential of dried beans

A total of 604 samples of about 7 different types of beans was examined to determine their mycological profiles, and suitability for use as solid substrates for mycotoxin production.All of the samples were collected from bean jam makers in Tokyo by the official food examiners.Genera Penicillium and Aspergillus were predominant, and genus Wallemia was also found commonly in all types of beans.Mycotoxin-producing Aspergillus strains were isolated from 52 samples of beans, approximately 9% of the total. The highest incidence of toxigenic Aspergillus (14.1%) was found in kidney beans. Red beans and peas inoculated with Aspergillus ochraceus were found to produce about 7 to 8 times more toxin than was obtained in a liquid medium, and red beans inoculated with A. versicolor produced more toxin than was obtained in yeast extract sucrose broth. Green peas inoculated with Fusarium graminearum produced about 8 times more T-2 toxin than was obtained in 1% peptone containing Czapek solution under comparable culture conditions.