scholarly journals Daphnia magna trade‐off safety from UV radiation for food

2021 ◽  
Author(s):  
Marcus Lee ◽  
Lars‐Anders Hansson
Keyword(s):  
Daphnia Magna ◽  
Uv Radiation ◽  
Trade Off

UV radiation influences covering behaviour in the urchin Lytechinus variegatus

2007 ◽  
Vol 87 (5) ◽  
pp. 1257-1261 ◽  
Author(s):  
Jessica E. Sigg ◽  
Karena M. Lloyd-Knight ◽  
Jean Geary Boal
Keyword(s):  
Uv Radiation ◽  
Functional Significance ◽  
Sea Urchins ◽  
Uv Exposure ◽  
Lytechinus Variegatus ◽  
Energetic Costs ◽  
Trade Off ◽  
Familiar Objects

Many species of sea urchins cover their bodies with a variety of materials. One hypothesis for this behaviour is that the urchins are reducing their exposure to UV radiation. The effect of UV radiation on the covering behaviour of twelve sea urchins, Lytechinus variegatus, was recorded and the shells used as covering materials were quantified. During UV exposure, urchins used significantly greater numbers, areas and masses of shells than did urchins during non-UV exposure. Results suggest that not only were L. variegatus covering in response to UV exposure, but they were also making distinct choices regarding preferred covering items. Unlike in previous studies, the urchins did not simply choose familiar objects or even the lightest objects; rather, when exposed to UV radiation they selected intermediate-sized objects, perhaps demonstrating a trade-off between the energetic costs of carrying objects and the physiological costs of exposure to UV radiation. While there appear to be many reasons for why urchins cover, these results indicate that urchin covering is non-random and has important functional significance.

Co-exposure of ZnO nanoparticles and UV radiation to Daphnia magna and Danio rerio : Combined effects rather than protection

2015 ◽  
Vol 35 (2) ◽  
pp. 458-467 ◽  
Author(s):  
Sofia L. Azevedo ◽  
Fabianne Ribeiro ◽  
Kerstin Jurkschat ◽  
Amadeu M.V.M. Soares ◽  
Susana Loureiro
Keyword(s):  
Daphnia Magna ◽  
Uv Radiation ◽  
Danio Rerio ◽  
Zno Nanoparticles ◽  
Combined Effects

Influence of Food Quantity and Lead Exposure on Maturation in Daphnia magna; Evidence for a Trade-Off Mechanism

1995 ◽  
Vol 9 (2) ◽  
pp. 175 ◽  
Author(s):  
E. L. Enserink ◽  
M. J. J. Kerkhofs ◽  
C. A. M. Baltus ◽  
J. H. Koeman
Keyword(s):  
Daphnia Magna ◽  
Lead Exposure ◽  
Trade Off ◽  
Food Quantity ◽  
Influence Of Food

scholarly journals Nano-TiO2 Phototoxicity in Fresh and Seawater: Daphnia magna and Artemia sp. as Proxies

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 55
Author(s):  
Ana C. Soler de la Vega ◽  
Alberto Cruz-Alcalde ◽  
Carmen Sans Mazón ◽  
Carlos Barata Martí ◽  
M. Silvia Diaz-Cruz
Keyword(s):  
Daphnia Magna ◽  
Uv Radiation ◽  
Engineered Nanoparticles ◽  
Indicator Organisms ◽  
Nano Tio2 ◽  
Micron Size ◽  
Reactive Halogen Species ◽  
Negative Impacts ◽  
Different Characteristics ◽  
Halogen Species

Nowadays, the industry is quite commonly using nanoparticles of titanium dioxide (nTiO2) especially in sunscreens, due to its higher reflective index in comparison to micron size TiO2. Its high demand causes its widespread environmental occurrence, thus damaging the environment. The aquatic ecosystems are the most vulnerable to contamination by nTiO2. Like other engineered nanoparticles, nTiO2 has demonstrated generation of reactive oxygen species (ROS) and reactive halogen species (RHS) in the aquatic environment under UV radiation. This study investigated the toxicity of nTiO2 towards two aquatic indicator organisms, one from freshwater (Daphnia magna) and the other from seawater (Artemia sp.), under simulated solar radiation (SSR). Daphnia magna and Artemia sp. were co-exposed in 16 h SSR and 8 h darkness cycles to different concentrations of nTiO2. The estimated EC50 at 48 h for D. magna was 3.16 mg nTiO2/L, whereas for A. sp. no toxic effects were observed. When we exposed these two organisms simultaneously to 48 h of prolonged SSR using higher nTiO2 concentrations, EC50 values of 7.60 mg/L and 5.59 mg/L nTiO2 for D. magna and A. sp., respectively, were obtained. A complementary bioassay was carried out with A. sp., by exposing this organism to a mixture of nTiO2 and organic UV filters (benzophenone 3 (oxybenzone, BP3), octocrylene (OC), and ethyl 4-aminobenzoate (EtPABA)), and then exposed to SSR. The results suggested that nTiO2 could potentially have negative impacts on these organisms, also this work outlines the different characteristics and interactions that may contribute to the mechanisms of environmental (in salted and freshwater) phototoxicity of nTiO2 and UV radiation, besides their interaction with organic compounds.

scholarly journals Responses of the Ecological Characteristics and Antioxidant Enzyme Activities in Rotaria Rotatoria to UV-B Radiation

2020 ◽  
Author(s):  
Ling-yun Zhu ◽  
Rong Huang ◽  
Ye Chen ◽  
Li-bin Zhou ◽  
Yi-long Xi ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Antioxidant Enzyme ◽  
Uv Radiation ◽  
Enzyme Activities ◽  
Life History Strategies ◽  
Antioxidant Enzyme Activities ◽  
Uvb Radiation ◽  
Bdelloid Rotifer ◽  
Trade Off ◽  
Energy Trade

Abstract Background: UVB radiation is an increasing threat to aquatic organisms, and also a potential driving force for zooplankton population dynamics. The bdelloid rotifer, for its parthenogenesis and high resistance to stress, can be used as an excellent model in ecology and evolutionary biology. Given the strong tolerance of bdelloid rotifer to stressors, we hypothesized that it could hold the ability to tolerate significant UV radiation, and this capacity may be associated with the trade-off strategies among life historic components. With this study, to estimate the ecological effects and responses of antioxidant system against UV radiation, the acute lethal, life history strategies, population growth, and antioxidant enzyme activities were assessed in the bdelloid Rotaria rotatoria after exposure to UV-B radiation. Results: The persistence of tolerance (evaluating by LT50) in rotifer to stress was playing a more vital role than the radiation dose (LD50) in survival, with a significant negative correlation between the radiation intensity and LT50. The larger the culture volume, the weaker the lethal effect. Rotifers prolonged their first reproductive time (JP), and shortened their reproductive period (RP) and longevity with the increasing of radiation dose, and the fecundity was significant inhibited by UV-B radiation. These responses can be taken as energy trade-off to retard their mortality. The population density of rotifers increased at the lowest dose of radiation, and then descended with the increasing of UVR dose, and this pattern was also corroborated by detecting the content of SOD and CAT, which suggested that hormesis also applies to R. rotatoria under UV-B radiation stress. The enzyme SOD has higher level of content and more sensitive to low UVR than CAT.Conclusions: The lethal effects of UV-B radiation to organisms depends not only on the conditions they exposed to, like as intensity and time of exposure, but also combination of factors namely, the type and effectiveness of the strategy they employ to cope with the changed environment. The species specificity, ages and physiological status also could be the regulating factors under the stresses, also in this case there was the strategy of energy trade-off between reproduction and survival in rotifers.

Membrane-bound vesicles associated with the microvilli in the midgut of the freshwater microcrustacean, Daphnia magna

1983 ◽  
Vol 41 ◽  
pp. 480-481
Author(s):  
Patricia L. Jansma
Keyword(s):  
Daphnia Magna ◽  
Intestinal Epithelial Cells ◽  
Uranyl Acetate ◽  
Intestinal Epithelial ◽  
Chlamydomonas Reinhardii ◽  
Thin Sections ◽  
Saturated Water ◽  
Cacodylate Buffer ◽  
Membrane Bound ◽  
Ethanol Series

The presence of the membrane bound vesicles or blebs on the intestinal epithelial cells has been demonstrated in a variety of vertebrates such as chicks, piglets, hamsters, and humans. The only invertebrates shown to have these microvillar blebs are two species of f1ies. While investigating the digestive processes of the freshwater microcrustacean, Daphnia magna, the presence of these microvillar blebs was noticed.Daphnia magna fed in a suspension of axenically grown green alga, Chlamydomonas reinhardii for one hour were narcotized with CO2 saturated water. The intestinal tracts were excised in 2% glutaraldehyde in 0.2 M cacodyl ate buffer and then placed in fresh 2% glutaraldehyde for one hour. After rinsing in 0.1 M cacodylate buffer, the sample was postfixed in 2% OsO4, dehydrated with a graded ethanol series, infiltrated and embedded with Epon-Araldite. Thin sections were stained with uranyl acetate and Reynolds lead citrate before viewing with the Philips EM 200.

Computer Reconstruction of the Cellular Architecture of the Daphnia Magna Optic Ganglion

1975 ◽  
Vol 33 ◽  
pp. 284-285
Author(s):  
E. R. Macagno ◽  
C. Levinthal
Keyword(s):  
Daphnia Magna ◽  
Genetic Background ◽  
Compound Eye ◽  
Synaptic Connectivity ◽  
Serial Sections ◽  
Cross Sectional ◽  
Small Crustacean ◽  
Optic Ganglion ◽  
Structural Invariance ◽  
High Degree

The optic ganglion of Daphnia Magna, a small crustacean that reproduces parthenogenetically contains about three hundred neurons: 110 neurons in the Lamina or anterior region and about 190 neurons in the Medulla or posterior region. The ganglion lies in the midplane of the organism and shows a high degree of left-right symmetry in its structures. The Lamina neurons form the first projection of the visual output from 176 retinula cells in the compound eye. In order to answer questions about structural invariance under constant genetic background, we have begun to reconstruct in detail the morphology and synaptic connectivity of various neurons in this ganglion from electron micrographs of serial sections (1). The ganglion is sectioned in a dorso-ventra1 direction so as to minimize the cross-sectional area photographed in each section. This area is about 60 μm x 120 μm, and hence most of the ganglion fit in a single 70 mm micrograph at the lowest magnification (685x) available on our Zeiss EM9-S.

Neutrophil Myeloperoxidase Destruction by Ultraviolet Irradiation

1988 ◽  
Vol 46 ◽  
pp. 138-139
Author(s):  
J. Hanker ◽  
B. Giammara ◽  
G. Strauss
Keyword(s):  
Uv Radiation ◽  
Myeloid Leukemia ◽  
Stratospheric Ozone ◽  
Psoriasis Patient ◽  
Whole Body ◽  
Human Neutrophils ◽  
Cupric Nitrate ◽  
The Earth ◽  
Routine Handling ◽  
Uvb Phototherapy

Only a fraction of the UV radiation emitted by the sun reaches the earth; most of the UVB (290-320nm) is eliminated by stratospheric ozone. There is increasing concern, however, that man-made chemicals are damaging this ozone layer. Although the effects of UV on DNA or as a carcinogen are widely known, preleukemia and acute myeloid leukemia (AML) have only rarely been reported in psoriasis patients treated with 8-methoxypsoralen and UV (PUVA). It was therefore of interest to study the effects of UV on the myeloperoxidase (MP) activity of human neutrophils. The peroxidase activity of enriched leukocyte preparations on coverslips was shown cytochemically with a diaminobenzidine medium and cupric nitrate intensification.Control samples (Figs. 1,4,5) of human bloods that were not specifically exposed to UV radiation or light except during routine handling were compared with samples which had been exposed in one of several different ways. One preparation (Fig. 2) was from a psoriasis patient who had received whole-body UVB phototherapy repeatedly.

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