Biomedical subjects

A Galizzi

Publications and source records attributed to A Galizzi.

62 records · Page 4Linked to original sources

PubMed1975

Mutant of Bacillus subtilis with a temperature-sensitive lesion in ribonucleic acid synthesis during germination.

We have isolated a mutant of Baccillus subtilis with a temperature-sensitive lesion in the process of spore germination. The temperature-sensitive mutation affects only germination and outgrowth, and the earliest defect observed is an early block of ribonucleic acid synthesis during germination at 46 C. Upon return to 35 C there is a complete repair of the impaired function, even in the absence of protein synthesis. Protein synthesis inhibition during germination of the mutant spores at 46 C has the effect of increasing the amount of ribonucleic acid made. The temperature-sensitive mutation is located near aroI.

Bacillus subtilis↗

PubMed1973

Interaction between deoxyribonucliec acid and distamycin A studied by transformation in Bacillus subtilis.

Distamycin A inhibits deoxyribonucleic acid (DNA)-mediated transformation and transfection in Bacillus subtilis at doses with little or no antibacterial effect. The inhibition of transformation parallels the inhibition of DNA uptake; further-more, during the transformation process, donor DNA molecules become distamycin and deoxyribonuclease resistant at the same time. This demonstrates that the drug acts by inhibiting DNA uptake. Although the drug is known to bind DNA, the inhibition is not related to affinity of the drug for DNA. This is shown by the lack of dependence of the extent of inhibition on DNA concentration, whereas the degree of inhibition depends upon cell concentration. Supporting this view is the fact that transformation by single-stranded DNA was also inhibited, even though the drug does not bind to denatured DNA. Distamycin A probably interferes with transformation by competing with DNA for some unknown bacterial component involved in transport of DNA into the cell.

Amidines↗

PubMed1973

Mutants of Bacillus subtilis temperature sensitive in the outgrowth phase of spore germination.

Thirteen thermosensitive mutants of Bacillus subtilis defective in the outgrowth phase of spore germination were isolated. The spores of the mutants grow into vegetative cells at 35 C but not at 47 C, whereas the vegetative cells grow equally well at both temperatures. At 47 C all the mutant spores are able to initiate germination, but the process stops at an early phase of outgrowth in one strain and in a late phase in the other 12 strains. The spore of the latter gives rise to a swollen cell unable to divide. In all mutants, the normal phenotype is restored when the spores are grown in the presence of 20% sucrose or 2% NaCl. The synthesis of deoxyribonucleic acid and proteins does not seem to be altered in the mutants giving swollen cells. The mutants were grouped into three distinct genetic classes by transformation.

Amino Acids↗

PubMed1971