scholarly journals Role of Dipicolinic Acid in Survival ofBacillus subtilis Spores Exposed to Artificial and Solar UV Radiation

2001 ◽  
Vol 67 (3) ◽  
pp. 1274-1279 ◽  
Author(s):  
Tony A. Slieman ◽  
Wayne L. Nicholson
Keyword(s):  
Uv Radiation ◽  
Dipicolinic Acid ◽  
Aqueous Suspension ◽  
Dry Weight ◽  
Full Spectrum ◽  
Solar Uv Radiation ◽  
Wet Heat ◽  
Solar Uv ◽  
Uv C

ABSTRACT Pyridine-2,6-dicarboxylic acid (dipicolinic acid [DPA]) constitutes approximately 10% of Bacillus subtilis spore dry weight and has been shown to play a significant role in the survival of B. subtilis spores exposed to wet heat and to 254-nm UV radiation in the laboratory. However, to date, no work has addressed the importance of DPA in the survival of spores exposed to environmentally relevant solar UV radiation. Air-dried films of spores containing DPA or lacking DPA due to a null mutation in the DPA synthetase operon dpaAB were assayed for their resistance to UV-C (254 nm), UV-B (290 to 320 nm), full-spectrum sunlight (290 to 400 nm), and sunlight from which the UV-B portion was filtered (325 to 400 nm). In all cases, air-dried DPA-less spores were significantly more UV sensitive than their isogenic DPA-containing counterparts. However, the degree of difference in UV resistance between the two strains was wavelength dependent, being greatest in response to radiation in the UV-B portion of the spectrum. In addition, the inactivation responses of DPA-containing and DPA-less spores also depended strongly upon whether spores were exposed to UV as air-dried films or in aqueous suspension. Spores lacking the gerA, gerB, and gerK nutrient germination pathways, and which therefore rely on chemical triggering of germination by the calcium chelate of DPA (Ca-DPA), were also more UV sensitive than wild-type spores to all wavelengths tested, suggesting that the Ca-DPA-mediated spore germination pathway may consist of a UV-sensitive component or components.

The role of solar UV radiation in the ecology of alpine lakes

2001 ◽  
Vol 62 (1-2) ◽  
pp. 35-42 ◽  
Author(s):  
Ruben Sommaruga
Keyword(s):  
Uv Radiation ◽  
Alpine Lakes ◽  
Solar Uv Radiation ◽  
Solar Uv

scholarly journals Apoptosis, the Role of Oxidative Stress and the Example of Solar UV Radiation

1999 ◽  
Vol 70 (4) ◽  
pp. 380-390 ◽  
Author(s):  
Charareh Pourzand ◽  
Rex M. Tyrrell
Keyword(s):  
Oxidative Stress ◽  
Uv Radiation ◽  
Solar Uv Radiation ◽  
Solar Uv

Role of urban and suburban aerosols on solar UV radiation over Athens, Greece

1998 ◽  
Vol 32 (12) ◽  
pp. 2193-2201 ◽  
Author(s):  
A. Papayannis ◽  
D. Balis ◽  
A. Bais ◽  
H. Van Der Bergh ◽  
B. Calpini ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Solar Uv Radiation ◽  
Solar Uv

scholarly journals Role of Dipicolinic Acid in Resistance and Stability of Spores of Bacillus subtilis with or without DNA-Protective α/β-Type Small Acid-Soluble Proteins

2006 ◽  
Vol 188 (11) ◽  
pp. 3740-3747 ◽  
Author(s):  
Barbara Setlow ◽  
Swaroopa Atluri ◽  
Ryan Kitchel ◽  
Kasia Koziol-Dube ◽  
Peter Setlow
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Bacillus Subtilis ◽  
Dipicolinic Acid ◽  
Dry Weight ◽  
Definitive Evidence ◽  
Dry Heat ◽  
Spore Resistance ◽  
Wet Heat

ABSTRACT Dipicolinic acid (DPA) comprises ∼10% of the dry weight of spores of Bacillus species. Although DPA has long been implicated in spore resistance to wet heat and spore stability, definitive evidence on the role of this abundant molecule in spore properties has generally been lacking. Bacillus subtilis strain FB122 (sleB spoVF) produced very stable spores that lacked DPA, and sporulation of this strain with DPA yielded spores with nearly normal DPA levels. DPA-replete and DPA-less FB122 spores had similar levels of the DNA protective α/β-type small acid-soluble spore proteins (SASP), but the DPA-less spores lacked SASP-γ. The DPA-less FB122 spores exhibited similar UV resistance to the DPA-replete spores but had lower resistance to wet heat, dry heat, hydrogen peroxide, and desiccation. Neither wet heat nor hydrogen peroxide killed the DPA-less spores by DNA damage, but desiccation did. The inability to synthesize both DPA and most α/β-type SASP in strain PS3664 (sspA sspB sleB spoVF) resulted in spores that lost viability during sporulation, at least in part due to DNA damage. DPA-less PS3664 spores were more sensitive to wet heat than either DPA-less FB122 spores or DPA-replete PS3664 spores, and the latter also retained viability during sporulation. These and previous results indicate that, in addition to α/β-type SASP, DPA also is extremely important in spore resistance and stability and, further, that DPA has some specific role(s) in protecting spore DNA from damage. Specific roles for DPA in protecting spore DNA against damage may well have been a major driving force for the spore's accumulation of the high levels of this small molecule.

Effects of solar UV radiation on birch and pine seedlings in the sub-Arctic

Polar Record ◽  
2002 ◽  
Vol 38 (206) ◽  
pp. 233-240 ◽  
Author(s):  
M. Turunen ◽  
M.-L. Sutinen ◽  
K. Derome ◽  
Y. Norokorpi ◽  
K. Lakkala
Keyword(s):  
Uv Radiation ◽  
Dry Weight ◽  
Growing Season ◽  
Control Treatment ◽  
Daily Maximum ◽  
Solar Uv Radiation ◽  
Growing Seasons ◽  
Acrylic Plate ◽  
Solar Uv ◽  
Uv Exclusion

AbstractThe responses of Betula pubescens Ehr. (European white birch), B. pendula Roth (silver birch) and two provenances of Pinus sylvestris L. (Scots pine) to solar ultraviolet (UV < 400 nm) radiation were investigated in a UV-exclusion field experiment during the 1997–99 growing seasons in Finnish Lapland (68°N). The seedlings were grown from seed under UV-B exclusion (a clear polyester filter) and UV-B/UV-A exclusion (a clear acrylic plate) as compared to control treatment (a polyethene filter) and ambient plants (no plastic filter). The mean daily maximum solar biologically effective UV-B irradiance (UV-BE) was 88 mW m-2, 68 mW m-2, and 91 mW m-2 for 1997, 1998, and 1999. A number of growth and biomass variables, PSII (Photosystem II) efficiency, and total concentration of nitrogen were recorded during and/or at the end of the experiment. Exposure (191 d) to solar UV radiation over three growing seasons did not cause many statistically significant UV effects in the growth or biomass of the seedlings. The only significant impacts of UV exclusion were found in P. sylvestris provenance Enontekiö. During the first growing season, the UVB/ UV-A exclusion treatment significantly accelerated the height increment (18–20%) off. sylvestris, and in the same seedlings, the UV-B exclusion treatment resulted in significantly increased dry weight of one-year-old needles (45–57%) after the second growing season. These UV impacts could not be seen at the end of the experiment or in any other species. The low concentration of N in current foliage was related to increased dry weight, but not to solar UV radiation (control vs UV exclusion). The present study indicated that solar UV radiation had limited, but sometimes transient, impacts on the growth of tree seedlings in the sub-Arctic. Longer-term field studies are needed, however, in order to detect the cumulative characteristics of the UV responses.

scholarly journals The attenuation of solar UV radiation in lakes and the role of dissolved organic carbon

1995 ◽  
Vol 40 (8) ◽  
pp. 1381-1391 ◽  
Author(s):  
Donald P. Morris ◽  
Horatio Zagarese ◽  
Craig E. Williamson ◽  
Esteban G. Balseiro ◽  
Bruce R. Hargreaves ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Uv Radiation ◽  
Solar Uv Radiation ◽  
Solar Uv

Diffuse Solar UV Radiation and Implications for Preventing Human Eye Damage¶

2001 ◽  
Vol 73 (2) ◽  
pp. 135 ◽  
Author(s):  
Alfio V. Parisi ◽  
Adele Green ◽  
Michael G. Kimlin
Keyword(s):  
Uv Radiation ◽  
Human Eye ◽  
Solar Uv Radiation ◽  
Eye Damage ◽  
Solar Uv

scholarly journals Biologically effective doses of ambient solar-UV radiation in Indonesia and Japan

2000 ◽  
pp. 123 ◽  
Author(s):  
Nobuo Munakata ◽  
Santoso Cornain ◽  
Ketut Mulyadi ◽  
Masamitsu Ichihashi ◽  
Joedo Prihartono ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Solar Uv Radiation ◽  
Solar Uv ◽  
Effective Doses

Effects of solar UV radiation on germination of conchospores and morphogenesis of sporelings in Porphyra haitanensis (Rhodophyta)

2007 ◽  
Vol 151 (5) ◽  
pp. 1751-1759 ◽  
Author(s):  
Hongxia Jiang ◽  
Kunshan Gao ◽  
E. Walter Helbling
Keyword(s):  
Uv Radiation ◽  
Porphyra Haitanensis ◽  
Solar Uv Radiation ◽  
Solar Uv
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