scholarly journals Effects of ultraviolet-B radiation on physiology, immune function and survival is dependent on temperature: implications for amphibian declines

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Niclas U Lundsgaard ◽  
Rebecca L Cramp ◽  
Craig E Franklin
Keyword(s):  
Low Temperature ◽  
Immune Function ◽  
Disease Susceptibility ◽  
Environmental Changes ◽  
Amphibian Declines ◽  
Ultraviolet B ◽  
Environmental Drivers ◽  
Conservation Strategies ◽  
Ultraviolet B Radiation ◽  
Mechanistic Basis

Abstract Multiple environmental changes are thought to be contributing to the widespread decline of amphibians in montane regions, but interactions between drivers of decline are not well understood. It has been proposed previously that elevated ultraviolet-B radiation (UBVR) and low temperatures may interact in their negative effects on health, immune function and disease susceptibility in exposed amphibians. In the present study, we chronically exposed larvae of the striped-marsh frog (Limnodynastes peronii) to a factorial combination of high and low UVBR and high and low temperature to assess interactive effects on growth, survival and indices of immune function. The high UVBR treatment reduced growth and survival of larvae compared to the low UVBR treatment at both temperatures, but the effects were significantly enhanced at low temperature. High UVBR exposure also induced a chronic inflammatory response as evidenced by an increase in the leucocyte proportion of total cells and altered the ratio of neutrophils to lymphocytes in the blood, highlighting a potential mechanistic basis for increased disease susceptibility in amphibians living at high altitudes. Our findings stress the importance of investigating environmental factors in combination when assessing their effects and highlight the mechanistic basis for how key environmental drivers in montane regions affect amphibian health. Continuation of this work is necessary for the development of targeted conservation strategies that tackle the root causes of montane amphibian declines.

scholarly journals Interactions Between Ultraviolet B Radiation, Warming, and Changing Nitrogen Source May Reduce the Accumulation of Toxic Pseudo-nitzschia multiseries Biomass in Future Coastal Oceans

2021 ◽  
Vol 8 ◽  
Author(s):  
Kyla J. Kelly ◽  
Fei-Xue Fu ◽  
Xiaowen Jiang ◽  
He Li ◽  
Dong Xu ◽  
...  
Keyword(s):  
Nitrogen Source ◽  
Carbon Fixation ◽  
Toxin Production ◽  
Ultraviolet B ◽  
Interactive Effects ◽  
Environmental Drivers ◽  
Near Surface ◽  
Ultraviolet B Radiation ◽  
Bloom Formation ◽  
Uvb Exposure

Understanding the environmental conditions that trigger Pseudo-nitzschia bloom formation and domoic acid (DA) production is critical as the frequency and severity of these toxic blooms increases in the face of anthropogenic change. However, predicting the formation of these harmful blooms in a future ocean remains a challenge. Previous studies have examined the effects of single environmental drivers on Pseudo-nitzschia spp. growth and toxin production, but few have considered the interactions between them. In this multiple driver study with Pseudo-nitzschia multiseries, we used a full factorial matrix experimental design to examine the simultaneous effects of temperature (20 and 25°C), nitrogen source (nitrate and urea), and irradiance (photosynthetically active radiation with and without ultraviolet B radiation; UVB). This strain of P. multiseries was unable to withstand prolonged exposures (>0.5 h) to 0.06 mw⋅cm–2 UVB light, with implications for near-surface bloom formation if future shallower mixed layers increase UVB exposure. Growth rates were inhibited by UVB, but photosynthesis and carbon fixation continued at a reduced capacity. Additionally, DA synthesis continued despite UVB-induced growth inhibition. Warming by 5°C enhanced cellular DA quotas three-fold. Within these warmer treatments, urea-grown cultures exposed to UVB had the highest amount of DA per cell, suggesting that interactive effects between UVB exposure, warming, and urea can synergistically enhance toxin production. However, overall production of toxic biomass was low, as growth-integrated DA production rates were near zero. This indicates that although Pseudo-nitzschia multiseries cell-specific toxicity could worsen in an anthropogenically-altered future ocean, bloom formation may be inhibited by increased exposure to UVB. This multi-variable experimental approach revealed previously unknown interactions that could not have been predicted based on combined effects of single-variable experiments. Although P. multiseries DA production may be enhanced in a future ocean, inherent sensitivity to prolonged UVB exposure may moderate trophic transfer of toxin to coastal food webs.

scholarly journals Allergic disease: understanding how in utero events set the scene

2010 ◽  
Vol 69 (3) ◽  
pp. 366-372 ◽  
Author(s):  
Susan L. Prescott
Keyword(s):  
Immune Function ◽  
Allergic Disease ◽  
Disease Susceptibility ◽  
Environmental Changes ◽  
Environmental Exposures ◽  
Immune Gene ◽  
Ongoing Research ◽  
Individual Vulnerability ◽  
Environmental Interactions ◽  
In Pregnancy

Events and exposures in pregnancy can have critical effects on fetal development with lasting implications for subsequent health and disease susceptibility. There is growing interest in how modern environmental changes influence fetal immune development and contribute to the recent epidemic of allergy and other immune disorders. Rising rates of allergic disease in early infancy, together with pre-symptomatic differences in immune function at birth, suggest that antenatal events play a predisposing role in the development of disease. A number of environmental exposures in pregnancy can modify neonatal immune function including diet, microbial exposure and maternal smoking, and there is emerging evidence from animal models that these factors may have epigenetic effects on immune gene expression and disease susceptibility. Furthermore, functional genetic polymorphisms also alter individual vulnerability to the effects of these environmental exposures, highlighting the complexity of gene–environmental interactions in this period. All these observations underscore the need for ongoing research to understand the pathogenesis and rising incidence of disease in the hope of better strategies to reverse this.

scholarly journals Early exposure to ultraviolet-B radiation decreases immune function later in life

2016 ◽  
Vol 4 (1) ◽  
pp. cow037 ◽  
Author(s):  
Emma Ceccato ◽  
Rebecca L. Cramp ◽  
Frank Seebacher ◽  
Craig E. Franklin
Keyword(s):  
Immune Function ◽  
Ultraviolet B ◽  
Early Exposure ◽  
Ultraviolet B Radiation

scholarly journals Physiology provides a window into how the multi-stressor environment contributes to amphibian declines

2020 ◽  
pp. 165-182
Author(s):  
Michel E.B. Ohmer ◽  
Lesley A. Alton ◽  
Rebecca L. Cramp
Keyword(s):  
Immune Function ◽  
Fungal Pathogens ◽  
Biodiversity Loss ◽  
Amphibian Declines ◽  
Stress Physiology ◽  
Amphibian Conservation ◽  
Environmental Drivers ◽  
Amphibian Disease ◽  
And Shifts ◽  
Conservation And Management

The amphibian disease chytridiomycosis, caused by two fungal pathogens in the genus Batrachochytrium, has caused the greatest vertebrate biodiversity loss due to disease in recorded history. Both the pathogens and their amphibian hosts are impacted by biotic and abiotic conditions that are rapidly changing due to anthropogenic causes, challenging our understanding of how the host–pathogen relationship will shift in the future. By examining this problem through a physiological lens, we can elucidate the mechanisms driving increased susceptibility to disease. This chapter first examines the physiological tools that can be used by amphibian biologists to measure aspects of immune function, stress physiology, and energy expenditure, and the main environmental drivers of these physiological shifts. Then, we explore case studies that have linked environmental change, immune function, and shifts in disease susceptibility to inform amphibian conservation and management.

Activation of HIV in Human Skin by Ultraviolet B Radiation and its Inhibition by NFκB Blocking Agents¶

2001 ◽  
Vol 74 (6) ◽  
pp. 805 ◽  
Author(s):  
Joan Breuer-McHam ◽  
Eric Simpson ◽  
Irene Dougherty ◽  
Makoto Bonkobara ◽  
Kiyoshi Ariizumi ◽  
...  
Keyword(s):  
Human Skin ◽  
Ultraviolet B ◽  
Ultraviolet B Radiation ◽  
Blocking Agents
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