In vitro reconstruction of the mitochondrial translation system of yeast.

We have isolated the translation system from yeast mitochondria and have reconstructed it in vitro. This submitochondrial system, composed of mitochondrial ribosomes, tRNA, pH 5 fraction and mRNA, is maximally active at 10 mM Mg2+ and 100 mM KCl or NH4Cl. NH4+ is more stimulatory than K+.

Intraspecific variation in the structural organization and redundancy of chloroplast ribosomal DNA cistrons in Euglena gracilis.

Chloroplast DNAs from six different laboratory collections of Euglena gracilis "strain Z" and var. bacillaris were analyzed with restriction endonucleases EcoRI and Bam HI. The most variable portion of the organelle genome is the region containing the ribosomal cistrons.

Gel Electrophoresis of Chloroplast Polypeptides: Comparison of One-Dimensional and Two-Dimensional Gel Analyses of Chloroplast Polypeptides From Euglena gracilis.

Euglena chloroplast polypeptides are resolved by an adaptation of the two-dimensional gel electrophoretic technique of O'Farrell (1975 J Biol Chem 250: 4007-4021). The present results are compared with those obtained by our earlier two-dimensional gel analyses as well as those obtained by one-dimensional gel analyses. Up to 75 micrograms of Euglena chloroplast polypeptides are resolved on one-dimensional sodium dodecylsulfate linear gradient 7.

The proportion of ribosomes active in protein synthesis and the content of polyribosomal poly(A)-containing RNA in adult and senescent rat livers.

The proportion of ribosomes active in protein synthesis and the content of polyribosomal poly(A)-containing RNA are unchanged when adult and senescent rat livers are compared. Therefore, the decreased protein synthesizing activity of senescent liver microsomes observed previously is not due to a deficiency in total mRNA content.

Total free amino acid levels in adult and senescent rat liver.

The total free amino acid content per gram of liver wet weight does not differ significantly between adult and senescent female rats, being 28.8 +/- 3.3 mumol in adult (13-17 months) and 26.

Phylogenetic origin of the chloroplast.

The 16S ribosomal RNA of the chloroplast of Euglena gracilis strain Z has been characterized in terms of its 2-dimensional electrophoretic "fingerprint" (T1 ribonuclease). Over 100 spots were resolved on the "fingerprint" and each spot was characterized as to which RNA oligonucleotide fragment(s) is contained. When compared to similar analyses of prokaryotic 16S rRNAs and eukaryotic cytoplasmic 18S rRNAs, the chloroplast 16S rRNA was a typically prokaryotic RNA, but bore little if any relationship to eukaryotic 18S rRNAs.

Hydrolytic enzymes of Euglena gracilis: characterization and activity as a function of culture age and carbon deprivation.

Optimal assay conditions are described for 8 hydrolases of Euglena gracilis var. bacillaris, SM-L1 (streptomycin-bleached) strain, 7 of which have an acid pH-optimum. Acid-phosphatase, beta-galactosidase, beta-glucosidase, b-fucosidase, cathepsin D, RNase, DNase, and an esterase are active in cell homogenates.

Phylogenetic origin of the chloroplast and prokaryotic nature of its ribosomal RNA.

The 16S ribosomal RNA of the Euglena gracilis chloroplast has been characterized in terms of its two-dimensional electrophoretic "fingerprint" (T1 ribonuclease). Results show it to be a typically prokaryotic 16 S rRNA. By the present criterion, different chloroplasts are shown to be related to one another and at least distantly to blue-green algae and perhaps to Bacillaceae.

Mitochondrial and cytoplasmic ribosomes. Distinguishing characteristics and a requirement for the homologous ribosomal salt-extractable fraction for protein synthesis.

1. Mitochondrial and cytoplasmic ribosomes of Euglena gracilis differ in their total RNA and protein content. 2.

Isolation of active polyribosomes from the cytoplasm, mitochondria and chloroplasts of Euglena gracilis.

1. A procedure is described for the isolation of intact polyribosomes from the cytoplasm, chloroplasts and mitochondria of Euglena gracilis. 2.