Effect of amino acid starvation on UV sensitivity of Lactobacillus acidophilus cells

Journal Article · Thu Nov 01 04:00:00 EST 1973 · Folia Microbiologica

DOI:https://doi.org/10.1007/BF02876792· OSTI ID:4343266

Soška, J.; Nečasová, J.

In Lactobacillus acidophilus cultures uv irradiated in the exponential phase of growth, the dose-survival curve was of the simple exponential type, without any shoulder. If the bacteria were subjected to amino acid starvation prior to irradiation, a shoulder corresponding to a quasi-threshold dose (D) of about 780 ergs/mm/sup 2/ appeared in the curve. The administration of protein- or RNA-synthesis inhibitors prior to irradiation had the same effect. The effect of pre-irradiation amino acid starvation was abolished by simuitaneous thymidine starvation. It was likewise abolished if amino acid starvation was followed by incubation in the presence of amino acids (without thymidine) and then by irradiation of the cells. Post-irradiation amino acid starvation did not lead to the formation of a shoulder but if combined with thymidine starvation it did. It can be concluded from the results that post-irradiation repair processes are facilitated or promoted if, during the post-irradiation interval DNA synthesis is delayed. This delay represents a compensation of the pre-irradiation increase of cellular DNA-content, taking place during inhibition of proteosynthesis. The post-irradiation administration of caffeine did not abolish the formation of the shoulder induced by pre-irradiation amino acid starvation; on the contrary, it induced its formation even in exponentially growing, irradiated control bacteria. (auth)

• Research Organization: Inst. of Biophysics, Brno
• Sponsoring Organization: USDOE
• NSA Number: NSA-29-015904
• OSTI ID: 4343266
• Journal Information: Folia Microbiologica, Journal Name: Folia Microbiologica Journal Issue: 6 Vol. 18; ISSN 0015-5632
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

*AMINO ACIDS-- RADIOSENSITIVITY EFFECTS
*CAFFEINE-- RADIOSENSITIVITY EFFECTS
*LACTOBACILLUS-- RADIOSENSITIVITY
*THYMIDINE-- RADIOSENSITIVITY EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOSYNTHESIS
DNA
FASTING
GROWTH
N48310* --Life Sciences--Radiation Effects on Microorganisms- -Basic Studies
PHOTON BEAMS
RESPONSE MODIFYING FACTORS
ULTRAVIOLET RADIATION