Search results

1

A new look at adaptive mutations in bacteria.

100%

Janion C.

|

2000

|

vol. 47

|

issue 2

451-457

EN

This is a short survey of the adaptive mutation processes that arise in non- or slowly- dividing bacterial cells and includes: (i) bacterial models in which adaptive mutations are studied; (ii) the mutagenic lesions from which these mutations derive; (iii) the influence of DNA repair processes on the spectrum of adaptive mutations. It is proposed that in starved cells, likely as during the MFD phenomenon, lesions in tRNA suppressor genes are preferentially repaired and no suppressor tRNAs are formed as a result of adaptive mutations. Perhaps the most provocative proposal is (iv) a hypothesis that the majority of adaptive mutations are selected in a pre-apoptotic state where the cells are either mutated, selected, and survive, or they die.

2

Some aspects of the SOS response system - A critical survey.

100%

Janion C.

|

2001

|

vol. 48

|

issue 3

599-610

EN

The SOS system and SOS mutagenesis are frequently studied, or exploited to obtain an increase in mutagenicity of bacteria. Here a short survey is made of the phenomenon of SOS response with special attention to latest and less discussed data, especially the induction of the SOS system in response to cell starvation or mutation of certain genes and the role of inducible DNA polymerases.

3

Mutator specificity of Escherichia coli alkB117 allele

51%

Nieminuszczy J., Janion C., Grzesiuk E.

|

2006

|

vol. 53

|

issue 2

425-428

EN

The Escherichia coli AlkB protein encoded by alkB gene was recently found to repair cytotoxic DNA lesions 1-methyladenine (1-meA) and 3-methylcytosine (3-meC) by using a novel iron-catalysed oxidative demethylation mechanism that protects the cell from the toxic effects of methylating agents. Mutation in alkB results in increased sensitivity to MMS and elevated level of MMS-induced mutations. The aim of this study was to analyse the mutational specificity of alkB117 in a system developed by J.H. Miller involving two sets of E. coli lacZ mutants, CC101-106 allowing the identification of base pair substitutions, and CC107-CC111 indicating frameshift mutations. Of the six possible base substitutions, the presence of alkB117 allele led to an increased level of GC→AT transitions and GC→TA and AT→TA transversions. After MMS treatment the level of GC→AT transitions increased the most, 22-fold. Among frameshift mutations, the most numerous were -2CG, -1G, and -1A deletions and +1G insertion. MMS treatment appreciably increased all of the above types of frameshifts, with additional appearance of the +1A insertion.

4

On the different response of Salmonella typhimurium hisG46 and TA1530 to mutagenic action of base analogues

50%

Janion C.

Acta Biochimica Polonica

|

1979

|

vol. 26

|

issue 1-2

171-177

5

Are Escherichia Coli dam^- as compared to dam^+ hypermutable by base analogs?

45%

Janion C., Bębenek K., Plewako S.

|

issue 2

183-193

6

Do DNA repair systems affect N^4-hydroxycytidine-induced mutagenesis?

44%

Śledziewska-Gójska E., Janion C.

Acta Biochimica Polonica

|

1983

|

vol. 30

|

issue 2

149-157

7

The N4-hydroxycytidine reduction system in toluenized cells of Salmonella typhimurium

38%

Popowska E., Janion C.

Acta Biochimica Polonica

|

1977

|

vol. 24

|

issue 3

197-205

8

Is the tRNA ochre suppressor supX derived from gltT?

32%

Płachta A., Janion C.

Acta Biochimica Polonica

|

1992

|

vol. 39

|

issue 3

265-269

9

Some problems of mutagenssis induced by base analogues

32%

Janion C.

|

Refine search results

9 Acta Biochimica Polonica

1 2006

1 2001

1 2000

1 1992

1 1987

1 1984

1 1983

1 1979

1 1977

9 Janion C.

1 Bębenek K.

1 Grzesiuk E.

1 Nieminuszczy J.

1 Plewako S.

1 Popowska E.

1 Płachta A.

1 Śledziewska-Gójska E.

A new look at adaptive mutations in bacteria.

Some aspects of the SOS response system - A critical survey.

Mutator specificity of Escherichia coli alkB117 allele

On the different response of Salmonella typhimurium hisG46 and TA1530 to mutagenic action of base analogues

Are Escherichia Coli dam^- as compared to dam^+ hypermutable by base analogs?

Do DNA repair systems affect N^4-hydroxycytidine-induced mutagenesis?

The N4-hydroxycytidine reduction system in toluenized cells of Salmonella typhimurium

Is the tRNA ochre suppressor supX derived from gltT?

Some problems of mutagenssis induced by base analogues