Synthesis of thymine and alpha-putrescinylthymine in bacteriophage phi W-14-infected Pseudomonas acidovorans.

Host DNA synthesis stopped about 10 min after the infection of Pseudomonas acidovorans with bacteriophage phi W-14, but host DNA was not degraded to acid-soluble fragments. The synthesis of host but not of phage DNA was inhibited by 5-fluorodeoxyuridine. The nucleotide pools of infected cells did not contain dTTP, and infection resulted in the appearance of dTTPase activity. Although ornithine labeled the alpha-putrescinylthymine residues of phi W-14 DNA, ornithine-labeled nucleotides were not detected in infected cells. A new deoxynucleoside triphosphate did appear in infected cells, but it was not labeled by ornithine. It is concluded that the thymine and alpha-putrescinylthymine in phi W-14 DNA are synthesized at the polynucleotide level.     

Terpenes from pittosporaceae

The monoterpenes of the fruits of Pittosporum resiniferum and P. undulatum have been identified. The essential oil of P. resiniferum contai     

Inhibition of selected fungi by bacterial isolates fromTripsacum dactyloides L.

Summary In an incubation study addition of green manure caused a reduction in the ammonia volatilized initially from both sodic and reclaimed soils but extensive volatilization occurred from the sodic soil, amended with green manure, after the tenth day till the conclusion of the experiment after 9 weeks. Volatilization from the reclaimed soil was much less. There was a slight build up of organic carbon and ammoniacal nitrogen in both the soils though greater in the reclaimed soil. More of nitrate and nitrite accumulated in the sodic soil.     

Endogenous respiration and regulation in a primitive marine fungus

The relationship between the respiration and the presence and utilization of endogenous and exogenous substrates was studied in the non-filamentous obligately marine fungus Thraustochytrium aureum. Using isotopic and manometric methods, it was shown that almost all exogenous glucose is assimilated, whilst almost all the oxygen consumption in the presence of exogenous glucose was due to oxidation of endogenous reserves. In contrast, exogenous glutamate, which cannot serve as the sole carbon source for growth, inhibits respiration of endogenous materials, and is itself rapidly oxidized. The uncoupler 2,4-dinitrophenol stimulates the oxidation of endogenous reserves without affecting the uptake and use of exogenous glucose. These data strongly support the idea of physiologic compartmentation in this organism.     

Amino acid deprivation induces synthesis of four proteins in chick embryo cells

Amino acid deprivation of chick embryo cells enhances the synthesis of four proteins whose molecular weights are approx. 89000, 73000, 35000 and 27000. This enhancement, which is seen in medium completely free of amino acids, can be prevented by the addition of any single amino acid. Furthermore, in the absence of amino acids in the medium, DNA and RNA synthesis is markedly inhibited, an effect which is similarly prevented by the addition of single amino acids. These new proteins synthesized in the amino acid-free medium co-migrate on one-dimensional gels with the ‘stress proteins’ induced by a variety of agents such as heavy metals, sulfhydryl reagents, heat shock, and amino acid analogues.     

Isolation and partial chemical characterization of the three major yolk polypeptides from Drosophila melanogaster.

The three major yolk polypeptides of Drosophila melanogaster have been isolated from yolk spheres of early embryos. Their molecular weights, as determined by SDS-polyacrylamide electrophoresis, are 44,000, 45,000, and 46,000. A number of approaches have been used to show that each of these yolk polypeptides are different. They have different isoelectric points, they have different digestion products upon peptide mapping by limited proteolysis, and they show three different antigen-antibody systems when each polypeptide is reacted with an antisera made to a mixture of all three. Both the digestion with chymotrypsin and the immunoelectrophoresis studies indicate similarities between two of the polypeptides while the third appears unique. This is the first example of multiple yolk polypeptides of similar molecular weight.     

Incompatibility group P-1 bla+ plasmids do not increase penicillin resistance of Pseudomonas acidovorans.

Incompatibility group P-1 plasmids with the bla+ genotype were transferred from various Escherichia coli strains to Pseudomonas acidovorans strain 29. When resistance to ampicillin was used as the criterion, none of these plasmids appeared able to express their Bla+ phenotype in this host. When the plasmids were subsequently transferred back from these ampicillin-sensitive P. acdiovorans transcipients to E. coli strains, it was found that the Bla+ phenotype was again expressed. Although beta-lactamase was not detected in cultures of P. acidovorans transcipients, macroiodometric determinations of beta-lactamase activity made on broken cell suspensions revealed that beta-lactamase was indeed synthesized. It was concluded that P. acidovorans strain 29 allows expression of the bla gene within the cell but that this organism is unable to excrete the enzyme.     

Ochratoxin A-induced iron deficiency anemia.

Ochratoxin A at 8 micrograms per g of diet, but not at lower doses, fed to chickens from 1 day to 3 weeks of age resulted in significantly (P less than 0.05) decreased packed blood cell volume and hemoglobin concentration without altering the number of circulating erythrocytes. Serum iron and percentage of transferrin saturation were lowered at 4 and 8 micrograms/g. Therefore, anemia was characteristic of severe ochratoxicosis of young chickens, and the anemia was categorized as a hypochromic-microcytic anemia of the iron deficiency type. These data indicate that ochratoxin A by itself does not cause hemorrhagic anemia syndrome of chickens and that an anemia caused by a nutritional deficiency can be elicited by a mycotoxin.