Alterations in the phospholipid composition of Nocardia polychromogenes during growth.

The major phospholipid classes of Nocardia polychromogenes were quantitated at different stages of the growth cycle. Significant differences were observed both in the total lipid phosphorus per g (dry weight) of cells, and in the relative percentages of individual phospholipids. The total amount of lipid-phosphorus increased throughout the growth cycle. Cardiolipin and phosphoinositides contents increased with significant decrease in phosphatidyl ethanolamine and unknown phospholipids.     

Alterations in the phospholipid composition ofNocardia polychromogenes during growth

Summary The major phospholipid classes ofNocardia polychromogenes were quantitated at different stages of the growth cycle. Significant differences were observed both in the total lipid phosphorus per g (dry weight) of cells, and in the relative percentages of individual phospholipids. The total amount of lipid-phosphorus increased throughout the growth cycle. Cardiolipin and phosphoinositides contents increased with significant decrease in phosphatidyl ethanolamine and unknown phospholipids.Acknowledgments. This investigation was supported in part by a grant from the Indian Council of Medical Research. Technical assistance of Mr Adarsh Kumar is acknowledged.     

Correlation between the susceptibility of E. coli to phagocytosis and their ability to invade HeLa cells in vitro.

The susceptibility of several strains of E. coli to phagocytic killing by polymorphonuclear lencocytes and the ability of the same strains to invade HeLa cells were studied. It was found that only the strains resistant to killing by leucocytes were able to penetrate and multiply within HeLa cells.     

Behavior of some microorganisms cultivated in the presence of irradiated maize starch]

The bactericidal effect of water soluble radiolysis products of Maize starch on Escherichia coli cultures declines when the initial population grows. This toxicity varies with the culture environment and the bacterial species: Bacillus subtilis, Lactobacillus plantarum, Streptococcus faecalis, Enterobacter sp. Moreover, for the eucaryote cell Saccharomyces cerevisiae, wild strain or muting "small colonies", only the generating time is altered by the active parts of radiolysis products. The results are analysed with regard to the hypothesis that the hydrogen peroxide is responsible for this toxicity.     

Correlation between the susceptibility of E. coli to phagocytosis and their ability to invade HeLa cells in vitro

Summary The susceptibility of several strains of E. coli to phagocytic killing by polymorphonuclear leucocytes and the ability of the same strains to invade HeLa cells were studied. It was found that only the strains resistant to killing by leucocytes were able to penetrate and multiply within HeLa cells.Acknowledgments. We thank Dr Bianca Pani who supplied us with HeLa cells. Supported by grant No. 75.00695.04 from the National Research Council of Italy (CNR).     

Changes in phospholipid composition ofNocardia polychromogenes during temperature adaptation

Summary The effect of growth temperature on the phospholipid composition of Nocardia polychromogenes has been examined. When the growth temperature was decreased from 37°C to 27°C, there was a large decrease in phosphatidyl ethanolamine with an increase in cardiolipin and phosphoinositides. These changes are discussed in context with the control of membrane fluidity.Acknowledgment. This investigation was financed in part by a grant from the Indian Council of Medical Research. Technical assistance of Mr Adarsh Kumar is acknowledged.     

Bacteriophage T4 mutants which propagate on E. coli K12 but not on E. coli B

Summary We have isolated and characterized 2 mutants of coliphage T4 which are able to propagate on E. coli K12 but not on E. coli B. We have assigned the mutations to genes 8 and 53, both structural genes. The products of genes 8 and 53 are found in the baseplate.Supported by grant No 3.519.75 from the Fonds national Suisse de la Recherche Scientifique.