Estimation of Biologically Damaging UV Levels in Marine Surface Waters with DNA and Viral Dosimeters¶

Wilhelm, Steven W.; Jeffrey, Wade H.; Suttle, Curtis A.; Mitchell, David

doi:10.1562/0031-8655(2002)0760268eobdul2.0.co2

Cited by 21 publications

(23 citation statements)

References 31 publications

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“…Jeffrey et al (1996) demonstrated that UV-B was responsible for 85% of the total leucine inhibition (30% relative to dark controls) when heterotrophic bacteria were exposed to full solar radiation in surface waters. From a linear relationship determined experimentally between the CPD formation in naked calf-thymus DNA dosimeters and the UV-B irradiance at 305 nm (Wilhelm et al 2002), we calculated a mean daily potential production of CPDs within Z m (regardless of photorepair processes): 420, 800 and 760 CPDs (Mb DNA) -1 at MAR, GYR and EGY, respectively. These daily potential productions were in the same range as those measured with DNA dosimeters in the surface waters of other oceanic areas: ~500 CPDs (Mb DNA) -1 in the Gulf of Mexico ) and 1000 CPDs (Mb DNA) -1 in the South coast of Curaçao (Boelen et al 2001, Visser et al 2002.…”

Section: Discussionmentioning

confidence: 99%

Diel variability of heterotrophic bacterial production and underwater UV doses in the eastern South Pacific

Wambeke¹,

Tedetti²,

Duhamel³

et al. 2009

Mar. Ecol. Prog. Ser.

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Diel variability of heterotrophic bacterial production (BP) was investigated in the eastern South Pacific from October to December 2004. Three sites differing by their trophic status were studied: Marquesas Islands, the center (GYR) and the eastern South Pacific Gyre. By using a Lagrangian approach and high frequency measurements, an important increase (2-to 4-fold) in BP was observed at the 3 sites during the afternoon-sunset period within surface layers. To evaluate the impact of solar UV radiation on this variability, we determined, from in situ optical measurements, the mean UV-B (at 305 nm) and UV-A (at 380 nm) doses received within the mixed layer at a daily scale. At GYR, the doses were as high as 0.3 and 11 kJ m -2 nm -1 for the whole day, respectively due to high surface irradiances and very low light attenuations in the water column. The UV-B/UV-A tri-hourly dose ratios (Q) displayed substantial variations during the daytime, with highest values recorded during the periods 9:00 to 12:00 h or 12:00 to 15:00 h. The negative linear correlation observed between Q and BP in the surface waters of GYR suggests that changes in the balance between DNA damages and photorepairs (reflected by changes in the Q-ratio) could have a significant influence on the diel variability of BP in open oceans. However, assessing the effects of UV radiation on diel variability of BP through an in situ measurement approach, independently from other causes like availability of resources, is not so evident, even in these clearest waters of the world ocean. KEY WORDS: Eastern South Pacific · Heterotrophic bacterial production · Diel variability · Ultraviolet radiation · UV-B and UV-A doses · Mixed layer · Leucine Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 387: [97][98][99][100][101][102][103][104][105][106][107][108] 2009 ural assemblages and bacterial cultures exposed to artificial UV-B after secondary irradiation with UV-A and PAR. It appears that UV-A is more efficient than PAR in inducing photoreactivation (Kaiser & Herndl 1997, Joux et al. 1999. Therefore, the rates of CPDs production and PERs in marine microbial assemblages may be related to the UV-B and UV-A doses (irradiances integrated over time) received by cells (Boelen et al. 2001). In the surface ocean, the intensity of UV-B and UV-A doses for a given time period depends on several parameters: (1) the level of surface UV-B and UV-A irradiances, (2) the attenuation of these surface irradiances in the water column, which is mainly controlled by chromophoric dissolved organic matter (CDOM) (Diaz et al. 2000) and (3) the depth of the mixed layer (Z m ), i.e. the depth at which cells can be transported within the upper water column (Boelen et al. 2001).The French project BIogeochemistry and Optics SOuth Pacific Experiment (BIOSOPE) was dedicated to a multidisciplinary exploration of the eastern South Pacific including the hyper-oligotrophic South Pacific Gyre (SPG) as well as its western (Marquesas Islands) and...

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Section: Discussionmentioning

confidence: 99%

Diel variability of heterotrophic bacterial production and underwater UV doses in the eastern South Pacific

Wambeke¹,

Tedetti²,

Duhamel³

et al. 2009

Mar. Ecol. Prog. Ser.

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“…Although estimates of in situ UVR risk are commonly obtained by exposing UV dosimeters to natural irradiance (e.g., Wilhelm et al 2002), the ability of these probes to predict real damage to fish larvae have been the object of only a few explicit experimental tests . Based on the literature, we predicted that (a) the negative effects on yellow perch larvae survival will be due to both UV-B and UV-A, similarly to what observed for the eggs of this species (Williamson et al 1997), (b) UV-B will be associated mostly to the accumulation of photodamage and only to a lesser extent to an increase in cytoplasmatic stress (SOD activity) (Kouwenberg et al 1999;Vetter et al 1999), and (c) UV-A should be associated mostly with an increase in SOD activity (Dong et al 2007;Zagarese and Williamson 2001).…”

Section: Introductionmentioning

confidence: 99%

The effects of UVR irradiance and spectral composition on yellow perch (Perca flavescens) larvae survival

et al. 2011

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The purpose of this study was to determine experimentally the effects of the quality (UV-A/UV-B ratio) and quantity (irradiance) of natural ultraviolet radiation (UVR) on the survival of yellow perch (Perca flavescens) larvae and on the oxidative stress in their cytoplasm, estimated by the activity of the superoxide dismutase (SOD). We also estimated the potential accumulation of photodamage in DNA by using UV dosimeters. Freshly-hatched yellow perch and UV dosimeters were incubated in controlled conditions under a factorial combination of selective and non-selective filters offering different levels of UVR protection and exposed to natural solar light. Larval survival was inversely related to the UVR intensity gradient, and responded similarly to the presence of both UV-A and UV-B or UV-A only. In contrast, the responses of SOD activity and UV dosimeter were stronger in the presence of both UV-A and UV-B than UV-A only, leading to a partial mismatch with the results on survival. Our results, obtained under natural solar light, suggest that incident UV-A radiation, despite its lower energy per unit photon than UV-B, could be a serious threat for yellow perch larvae. They also show that UV dosimeters and SOD activity predict only some components of UVR risk for yellow perch larvae. The partial mismatch between UV dosimeters results and larval survival cautions against the use of UV dosimeters alone as a proxy for UVR risk in the field.

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“…With at least 10 31 bacteriophages in Earth's biosphere (1)(2)(3)(4)(5), these living entities are the most abundant on the planet and play a major role in the evolution of novel genes, horizontal gene transfer, and maintenance of environmental and ecological balance (for recent reviews, see references 6 to 12). However, little is known about the complexity and diversity of these organisms.…”

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confidence: 99%

The Genomes, Proteomes, and Structures of Three Novel Phages That Infect the Bacillus cereus Group and Carry Putative Virulence Factors

Grose

Belnap

Jensen

et al. 2014

J Virol

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This article reports the results of studying three novel bacteriophages, JL, Shanette, and Basilisk, which infect the pathogen Bacillus cereus and carry genes that may contribute to its pathogenesis. We analyzed host range and superinfection ability, mapped their genomes, and characterized phage structure by mass spectrometry and transmission electron microscopy (TEM). The JL and Shanette genomes were 96% similar and contained 217 open reading frames (ORFs) and 220 ORFs, respectively, while Basilisk has an unrelated genome containing 138 ORFs. Mass spectrometry revealed 23 phage particle proteins for JL and 15 for Basilisk, while only 11 and 4, respectively, were predicted to be present by sequence analysis. Structural protein homology to wellcharacterized phages suggested that JL and Shanette were members of the family Myoviridae, which was confirmed by TEM. The third phage, Basilisk, was similar only to uncharacterized phages and is an unrelated siphovirus. Cryogenic electron microscopy of this novel phage revealed a T‫9؍‬ icosahedral capsid structure with the major capsid protein (MCP) likely having the same fold as bacteriophage HK97 MCP despite the lack of sequence similarity. Several putative virulence factors were encoded by these phage genomes, including TerC and TerD involved in tellurium resistance. Host range analysis of all three phages supports genetic transfer of such factors within the B. cereus group, including B. cereus, B. anthracis, and B. thuringiensis. This study provides a basis for understanding these three phages and other related phages as well as their contributions to the pathogenicity of B. cereus group bacteria. IMPORTANCEThe Bacillus cereus group of bacteria contains several human and plant pathogens, including B. cereus, B. anthracis, and B. thuringiensis. Phages are intimately linked to the evolution of their bacterial hosts and often provide virulence factors, making the study of B. cereus phages important to understanding the evolution of pathogenic strains. Herein we provide the results of detailed study of three novel B. cereus phages, two highly related myoviruses (JL and Shanette) and an unrelated siphovirus (Basilisk). The detailed characterization of host range and superinfection, together with results of genomic, proteomic, and structural analyses, reveal several putative virulence factors as well as the ability of these phages to infect different pathogenic species.

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Estimation of Biologically Damaging UV Levels in Marine Surface Waters with DNA and Viral Dosimeters¶

Cited by 21 publications

References 31 publications

Diel variability of heterotrophic bacterial production and underwater UV doses in the eastern South Pacific

Diel variability of heterotrophic bacterial production and underwater UV doses in the eastern South Pacific

The effects of UVR irradiance and spectral composition on yellow perch (Perca flavescens) larvae survival

The Genomes, Proteomes, and Structures of Three Novel Phages That Infect the Bacillus cereus Group and Carry Putative Virulence Factors

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