Ultraviolet sensitivity and photoproducts in spore-like bodies of an excision-repair-deficient and dipicolinic-acid-less strain of Bacillus subtilis

1975 ◽  
Vol 21 (7) ◽  
pp. 1129-1132 ◽  
Author(s):  
N. Munakata ◽  
P. C. Fitz-James ◽  
I. E. Young
Keyword(s):  
Bacillus Subtilis ◽  
Ultraviolet Light ◽  
Uv Irradiation ◽  
Excision Repair ◽  
Dipicolinic Acid ◽  
Subtilis Strain ◽  
Sporulation Medium ◽  
Ultraviolet Sensitivity ◽  
Cyclobutane Dimers ◽  
Spore Photoproduct

Bacillus subtilis strain UVS-42DPA is defective in both excision-repair capability and dipicolinic acid (DPA) accumulation. In sporulation medium, it forms spore-like bodies, which are as sensitive to ultraviolet light (UV) as the vegetative cells and produce mostly cyclobutane dimers instead of "spore photoproduct" upon UV irradiation. The results suggest that the drastic change in the photochemical reactivity of DNA during sporulation might be induced and (or) maintained by the accumulation of DPA.

scholarly journals SENSITIVITY OF MEIOTIC YEAST CELLS TO ULTRAVIOLET LIGHT

Genetics ◽  
1973 ◽  
Vol 73 (4) ◽  
pp. 531-541
Author(s):  
G Simchen ◽  
Y Salts ◽  
R Piñon
Keyword(s):  
Dna Repair ◽  
Dna Synthesis ◽  
Ultraviolet Light ◽  
Uv Irradiation ◽  
Ultraviolet Irradiation ◽  
Meiotic Prophase ◽  
Yeast Cells ◽  
Repair System ◽  
Sporulation Medium ◽  
Sporulation Process

ABSTRACT Sporulating cells of Szccharomyces cereuisiae show an increasing sensitivity to ultraviolet irradiation. Maximum sensitivity is reached at a time comparable to meiotic prophase. Sensitivity is expressed as reduced sporulation after the irradiation. The uv effect can be efficiently reversed by photoreactivating light. Viability is also morc severely affected during premeiotic DNA synthesis and during meiosis than in earlier stages in sporulation. Cells left in sporulation medium after the irradiation show a reduced viability compared with the cells plated immediately after the irradiation. Non-sporulating diploids do not acquire sensitivity when exposed to sporulation medium, hence the sensitivity is related to the sporulation process. That meiosis itself is affected, rather than spore formation alone, is evident from experiments in which the uv irradiation interferes with the uncovering of a recessive marker and with commitment to meiosis. It is proposed that during meiotic prophase, the DNA repair system is different from that found in vegetative cells.

Ultraviolet light induced thymine dimers and repair processes in the alga Eudorina elegans

1972 ◽  
Vol 18 (12) ◽  
pp. 1809-1815 ◽  
Author(s):  
C. L. Kemp ◽  
M. S. Tsao ◽  
G. Thorson
Keyword(s):  
Visible Light ◽  
Ultraviolet Light ◽  
Green Alga ◽  
Uv Irradiation ◽  
Excision Repair ◽  
Uv Exposure ◽  
Dark Repair ◽  
Thymine Dimer ◽  
Thymine Dimers ◽  
Cellular Dna

A fraction of the cellular DNA of the colonial green alga Eudorina elegans strain 1193 can be specifically labeled with 3H-thymidine but not by 3H-thymine. Ultraviolet (UV) irradiation of E. elegans leads to the production of thymine dimers as determined by extraction, hydrolysis, and chromatography of 3H-thymidine-labeled cells. Removal of dimers occurs by processes involving visible light (photoreactivation), but dark repair (excision repair) has not been detected in the labeled fraction. A relationship between UV exposure and thymine dimer production has been determined.

scholarly journals Properties of Spores of Bacillus subtilis Blocked at an Intermediate Stage in Spore Germination

2001 ◽  
Vol 183 (16) ◽  
pp. 4894-4899 ◽  
Author(s):  
Barbara Setlow ◽  
Elizabeth Melly ◽  
Peter Setlow
Keyword(s):  
Enzyme Activity ◽  
Bacillus Subtilis ◽  
Uv Irradiation ◽  
Spore Germination ◽  
Dipicolinic Acid ◽  
Intermediate Stage ◽  
Stage I ◽  
Wild Type ◽  
Resistance To Heat

ABSTRACT Germination of mutant spores of Bacillus subtilisunable to degrade their cortex is accompanied by excretion of dipicolinic acid and uptake of some core water. However, compared to wild-type germinated spores in which the cortex has been degraded, the germinated mutant spores accumulated less core water, exhibited greatly reduced enzyme activity in the spore core, synthesized neither ATP nor reduced pyridine or flavin nucleotides, and had significantly higher resistance to heat and UV irradiation. We propose that the germinated spores in which the cortex has not been degraded represent an intermediate stage in spore germination, which we term stage I.

scholarly journals Maturation of Released Spores Is Necessary for Acquisition of Full Spore Heat Resistance during Bacillus subtilis Sporulation

2011 ◽  
Vol 77 (19) ◽  
pp. 6746-6754 ◽  
Author(s):  
Jose-Luis Sanchez-Salas ◽  
Barbara Setlow ◽  
Pengfei Zhang ◽  
Yong-qing Li ◽  
Peter Setlow
Keyword(s):  
Bacillus Subtilis ◽  
Heat Resistance ◽  
Uv Radiation ◽  
Dipicolinic Acid ◽  
Sporulation Medium ◽  
Content Type ◽  
Dry Heat ◽  
Lower Resistance ◽  
Wet Heat ◽  
Spore Maturation

ABSTRACTThe first ∼10% of spores released from sporangia (early spores) duringBacillus subtilissporulation were isolated, and their properties were compared to those of the total spores produced from the same culture. The early spores had significantly lower resistance to wet heat and hypochlorite than the total spores but identical resistance to dry heat and UV radiation. Early and total spores also had the same levels of core water, dipicolinic acid, and Ca and germinated similarly with several nutrient germinants. The wet heat resistance of the early spores could be increased to that of total spores if early spores were incubated in conditioned sporulation medium for ∼24 h at 37°C (maturation), and some hypochlorite resistance was also restored. The maturation of early spores took place in pH 8 buffer with Ca2+but was blocked by EDTA; maturation was also seen with early spores of strains lacking the CotE protein or the coat-associated transglutaminase, both of which are needed for normal coat structure. Nonetheless, it appears to be most likely that it is changes in coat structure that are responsible for the increased resistance to wet heat and hypochlorite upon early spore maturation.

scholarly journals DNA repair and the evolution of transformation in Bacillus subtilis. II. Role of inducible repair.

Genetics ◽  
1989 ◽  
Vol 121 (3) ◽  
pp. 411-422
Author(s):  
M F Wojciechowski ◽  
M A Hoelzer ◽  
R E Michod
Keyword(s):  
Dna Repair ◽  
Bacillus Subtilis ◽  
Plasmid Dna ◽  
Excision Repair ◽  
Physiological State ◽  
Transformation Rate ◽  
Exogenous Dna ◽  
Expression Of Genes ◽  
Cell Subpopulations ◽  
Experimental Treatments

Abstract In Bacillus subtilis, DNA repair and recombination are intimately associated with competence, the physiological state in which the bacterium can bind, take up and recombine exogenous DNA. Previously, we have shown that the homologous DNA transformation rate (ratio of transformants to total cells) increases with increasing UV dosage if cells are transformed after exposure to UV radiation (UV-DNA), whereas the transformation rate decreases if cells are transformed before exposure to UV (DNA-UV). In this report, by using different DNA repair-deficient mutants, we show that the greater increase in transformation rate in UV-DNA experiments than in DNA-UV experiments does not depend upon excision repair or inducible SOS-like repair, although certain quantitative aspects of the response do depend upon these repair systems. We also show that there is no increase in the transformation rate in a UV-DNA experiment when repair and recombination proficient cells are transformed with nonhomologous plasmid DNA, although the results in a DNA-UV experiment are essentially unchanged by using plasmid DNA. We have used din operon fusions as a sensitive means of assaying for the expression of genes under the control of the SOS-like regulon in both competent and noncompetent cell subpopulations as a consequence of competence development and our subsequent experimental treatments. Results indicate that the SOS-like system is induced in both competent and noncompetent subpopulations in our treatments and so should not be a major factor in the differential response in transformation rate observed in UV-DNA and DNA-UV treatments. These results provide further support to the hypothesis that the evolutionary function of competence is to bring DNA into the cell for use as template in the repair of DNA damage.

scholarly journals Molecular Physiological Characterization of a High Heat Resistant Spore Forming Bacillus subtilis Food Isolate

2021 ◽  
Vol 9 (3) ◽  
pp. 667
Author(s):  
Zhiwei Tu ◽  
Peter Setlow ◽  
Stanley Brul ◽  
Gertjan Kramer
Keyword(s):  
Bacillus Subtilis ◽  
Heat Resistance ◽  
Dipicolinic Acid ◽  
Laboratory Strain ◽  
High Heat ◽  
High Heat Resistance ◽  
Vegetative Cells ◽  
Heat Resistant ◽  
Food Isolate ◽  
Wet Heat

Bacterial endospores (spores) are among the most resistant living forms on earth. Spores of Bacillus subtilis A163 show extremely high resistance to wet heat compared to spores of laboratory strains. In this study, we found that spores of B. subtilis A163 were indeed very wet heat resistant and released dipicolinic acid (DPA) very slowly during heat treatment. We also determined the proteome of vegetative cells and spores of B. subtilis A163 and the differences in these proteomes from those of the laboratory strain PY79, spores of which are much less heat resistant. This proteomic characterization identified 2011 proteins in spores and 1901 proteins in vegetative cells of B. subtilis A163. Surprisingly, spore morphogenic protein SpoVM had no homologs in B. subtilis A163. Comparing protein expression between these two strains uncovered 108 proteins that were differentially present in spores and 93 proteins differentially present in cells. In addition, five of the seven proteins on an operon in strain A163, which is thought to be primarily responsible for this strain’s spores high heat resistance, were also identified. These findings reveal proteomic differences of the two strains exhibiting different resistance to heat and form a basis for further mechanistic analysis of the high heat resistance of B. subtilis A163 spores.

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