ABSTRACT
Bal31 deletion experiments on clones of the PaeR7 restriction-modification system from Pseudomonas aeruginosa demonstrate that it is arranged as an operon, with the methylase gene preceding the endonuclease gene. The DNA sequence of this operon agrees with in vitro transcription-translation assays which predict proteins of 532 amino acids, Mr = 59,260 daltons, and 246 amino acids, Mr = 27,280 daltons, coincident with the methylase and endonuclease genes, respectively. These predicted values coincide with the measured molecular weights of the purified, denatured PaeR7 endonuclease and methylase proteins. The first twenty amino acids from the amino-terminus of the purified endonuclease exactly match those predicted from the DNA sequence. Finally, potential regulatory mechanisms for the expression of phage restriction are described based on the properties of several PaeR7 subclones.
Subject(s)
DNA Restriction Enzymes/genetics , DNA-Cytosine Methylases , Deoxyribonucleases, Type II Site-Specific , Methyltransferases/genetics , Pseudomonas aeruginosa/genetics , Amino Acid Sequence , Base Sequence , Cell-Free System , Cloning, Molecular , DNA Restriction Enzymes/isolation & purification , Escherichia coli , Genes , Genes, Bacterial , Methyltransferases/isolation & purification , Plasmids , Protein Biosynthesis , Transcription, GeneticABSTRACT
The oxidation of methanol follows a well-defined pathway and is similar for several methylotrophic yeasts. The use of methanol as the sole carbon source for the growth of Pichia pastoris stimulates the expression of a family of genes. Three methanol-responsive genes have been isolated; cDNA copies have been made from mRNAs of these genes, and the protein products from in vitro translations have been examined. The identification of alcohol oxidase as one of the cloned, methanol-regulated genes has been made by enzymatic, immunological, and sequence analyses. Methanol-regulated expression of each of these three isolated genes can be demonstrated to occur at the level of transcription. Finally, DNA subfragments of two of the methanol-responsive genomic clones from P. pastoris have been isolated and tentatively identified as containing the control regions involved in methanol regulation.
Subject(s)
Alcohol Oxidoreductases/genetics , Ascomycota/genetics , Genes, Fungal , Methanol/pharmacology , Pichia/genetics , Base Sequence , DNA/genetics , DNA, Fungal/isolation & purification , Gene Expression Regulation/drug effects , Genes, Regulator , Methanol/metabolism , Pichia/enzymology , Promoter Regions, Genetic , Transcription, Genetic/drug effectsABSTRACT
The cardiorespiratory effects of etomidate were measured in two groups of six patients with aortic or mitral valve disease. The induction of anaesthesia with etomidate 0.3 mg kg-1 was followed by a second dose 10 min later. After the first dose, a 19% decrease in systemic arterial pressure was associated with a decrease in systemic vascular resistance and left ventricular heart work. Cardiac index, pulmonary artery pressure and wedge pressure all decreased slightly. Central venous pressure and heart rate did not change. A slight increase in respiratory frequency failed to prevent an increase in PACO2. Changes after the second dose were similar. The two groups of patients did not differ significantly in their response to etomidate. No patient complained of pain during injection, nor did myoclonic movements occur.
