Short-term Temperature Increase Research Articles

Different response of females and males Neotropical catfish (Rhamdia quelen) upon short-term temperature increase.

Climate change has been one of the most discussed topics in the world. Global warming is characterized by an increase in global temperature, also in aquatic environments. The increased temperature can affect aquatic organisms with lethal and sublethal effects. Thus, it is necessary to understand how different species respond to temperature. This study aimed to evaluate how the Neotropical catfish species Rhamdia quelen responds to temperature increases. The fish were exposed to temperatures of 25°C (control) and 30°C after gradual temperature increase for 7days. After 96h in each temperature, the fish were anesthetized, blood was collected, and after euthanasia, brain, liver, posterior kidney, gills, muscle, and gonads were collected. The gonads were used for sexing, while other tissues were used for the hematological, biochemical, genotoxic, and histopathological biomarkers analysis. Hepatic proteomic analysis with a focus on energy production was also carried out. Blood parameter changes in both sexes, including an increase in glucose in males, leukopenia in females, and genotoxicity in both sexes. Hepatic proteins related to energy production were altered in both sexes, but mainly in males. Others biomarker alterations, such as histopathological, were not observed in other tissues; however, the antioxidant system was affected differently between sexes. These showed that R. quelen juveniles, at temperatures higher than its optimum temperature such as 30°C, has several sublethal changes, such as hematological alterations, antioxidant system activation, and energetic metabolism alteration, especially in males. Thus, short-term temperature rise can affect females and males of R. quelen differently.

Effects of a short-term temperature increase on arthropod communities associated with pastures.

The impact of climate change on islands is expected to cause dramatic consequences on native biodiversity. However, limited data are available for arthropod communities in island agroecosystems. In this study, we simulate a small-scale climatic change (average of +1.2°C), using Open Top Chambers (OTCs) in forage crops in the Azores Archipelago (Portugal) and test the responses of arthropod communities associated with intensively-managed pastures. At three sites, twenty 1 x 1 m plots were established: 10 treatment plots with OTCs and 10 control plots. Arthropods were sampled with pitfall traps on two sampling events (winter and summer of 2020). When considering all species collected, arthropods' abundance was lower in OTCs. Specific taxa, namely spiders and beetles, showed a fast response to the OTCs' presence. The assemblage of non-indigenous spiders well adapted to pastures showed a significant difference in diversity with a slightly greater richness, but lower abundance inside the warmer plots. However, the presence of OTCs resulted in a decrease in beetle richness and abundance. This decline may be attributed to the multiple effects of warming. Therefore, it is imperative to conduct further investigations to elucidate the ecological processes that underlie the observed patterns.

Labile substrate input weakens the memory effect of soil microbial functions under global warming

The feedback between soil carbon (C) and climate change has the potential to decrease over time, which is mainly due to the thermal acclimation of microbial decomposition of soil organic matter (SOM). The adaption and stabilization mechanisms of microbial functions in response to long-term warming in agroecosystems, however, remain intensive debate. Therefore, we explored the controls of thermal acclimation based on an 8-year field warming (ambient, +1.6 °C, +3.2 °C) in agroecosystem and a short-term incubation at five constant temperature levels (from 5 to 25 °C with 5 °C intervals) under microbial steady-state (without glucose, non-activated microbial community) and activate microbial growth induced by sufficient glucose addition. At the steady-state, field warming (+3.2 °C) increased the specific growth rate whilst decreased the portion of growing microbial biomass as compared to ambient soils. This indicated that 8-year field warming facilitated the consumption of labile organics due to faster microbial growth. Consequently, microbial growth, activities of β-glucosidase and leucine aminopeptidase, as well as microbial respiration acclimated to field warming (+1.6 °C, +3.2 °C) over 8-year, responded up to 40% weaker to further short-term temperature increase (above 15 °C). Also, the temperature sensitivity of enzyme activity decreased with field warming magnitude under higher incubation temperatures, which further indicated enzyme acclimation. Under activation mode, however, the higher enzyme activities suggested that the increased labile C remarkably relieved the substrate limitation of microbial growth and activated dormant microorganisms in field warmed soils, and weaken the thermal acclimation of soil microbial functions. We thus found experimental evidence that the transition between microbial physiological states (i.e., dormant vs. active) owing to variations in C availability is the most plausible explanation for the alterations in temperature sensitivity of enzyme activities and microbial respiration. The compensating effect of the increased labile substrate under climate warming on the thermal acclimation of soil microbe-driven CO2 may thus be larger than that currently predicted, with important consequences for atmospheric CO2 concentrations.

The impact of daily mean air temperature on the proportion of time in hypoglycemia in 2,582 children and adolescents with type 1 diabetes – Is this association clinically relevant?

ObjectivesTo study the potential association between increases in daily mean air temperature and time below range (TBR <54 mg/dl) and time above range (TAR >250 mg/dl) in children and adolescents with type 1 diabetes. Research design and methodsIndividuals with type 1 diabetes <21 years with information on daily glucose profiles from the diabetes prospective follow-up study (DPV) were included (n = 2582). Further inclusion criteria were age at least 6 months at diabetes onset, diabetes duration for at least one year and treatment years 2020–2021. Mean daily air temperature and other meteorological parameters from 78 measurement stations in Germany were linked to the individual glucose sensor profile via the five-digit postcode areas of residency. We used multivariable repeated measures fractional logistic regression models with a compound symmetry covariance structure to study the association between a 1 °C increase in daily mean temperature and time in specific glucose ranges. ResultsA 1 °C increase in daily mean temperature was associated with an acute (Odds Ratio (OR) 1.009 (95%-CI 1.007, 1.011)) and up to 7 days delayed (OR 1.003 (1.001, 1.005)) increase in TBR <54 mg/dl. Moreover, an acute decrease in TAR >250 mg/dl (OR 0.997 (0.996, 0.997)) was found. ConclusionsResults of the DPV registry showed small, but statistically significant changes in TBR and TAR in association with a short-term temperature increase. Higher blood flow and faster insulin absorption might be one possible mechanism. In times of increasing temperature fluctuations meteorological impacts on time in range could become even more relevant.

Digestive enzyme activity and macromolecule content in the hemolymph of differentially adapted Lymantria dispar L. populations after short-term increases in ambient temperature

Global, unpredictable temperature increases have strong effects on all organisms, especially insects. Elucidating the effects of short-term temperature increases on midgut digestive enzymes (α-glucosidase, lipase, trypsin, and leucine aminopeptidase - LAP) and metabolic macromolecules in the hemolymph (proteins, lipids, and trehalose) of phytophagous pest larvae of Lymantria dispar is important for general considerations of insect adaptation to a warming climate and potential pest control options. We also wanted to determine whether the different adaptations of L. dispar populations to environmental pollution might affect their ability to cope with heat stress using larvae from the undisturbed, Kosmaj forest and disturbed, Lipovica forest. Heat treatments at 28 °C increased α-glucosidase activity in both larval populations, inhibited LAP activity in larvae from the polluted forest, and had no significant effect on trypsin and lipase activities, regardless of larval origin. The concentration of proteins, lipids, and trehalose in the hemolymph of larvae from the disturbed forest increased, whereas the population from the undisturbed forest showed only an increase in proteins and lipids after the heat treatments. Larval mass was also increased in larvae from the undisturbed forest. Our results suggest a higher sensitivity of digestive enzymes and metabolism to short-term heat stress in L. dispar populations adapted to pollution in their forest habitat, although climate warming is not beneficial even for populations from unpolluted forests. The digestive and metabolic processes of L. dispar larvae are substantially affected by sublethal short-term increases in ambient temperature.

Rubisco deactivation and chloroplast electron transport rates co-limit photosynthesis above optimal leaf temperature in terrestrial plants

Net photosynthetic CO2 assimilation rate (An) decreases at leaf temperatures above a relatively mild optimum (Topt) in most higher plants. This decline is often attributed to reduced CO2 conductance, increased CO2 loss from photorespiration and respiration, reduced chloroplast electron transport rate (J), or deactivation of Ribulose-1,5-bisphosphate Carboxylase Oxygenase (Rubisco). However, it is unclear which of these factors can best predict species independent declines in An at high temperature. We show that independent of species, and on a global scale, the observed decline in An with rising temperatures can be effectively accounted for by Rubisco deactivation and declines in J. Our finding that An declines with Rubisco deactivation and J supports a coordinated down-regulation of Rubisco and chloroplast electron transport rates to heat stress. We provide a model that, in the absence of CO2 supply limitations, can predict the response of photosynthesis to short-term increases in leaf temperature.

Effect of Elevated Temperature and Annealing Time on Mechanical Properties of Ti/Cu Bimetal

The paper presents the results of the elastoplastic properties of Ti/Cu bimetallic rods. They were obtained by extrusion and composed of a copper core with a covered titanium layer. Experiments were carried out at room temperature on virgin samples, and samples were subjected to prior annealing in the temperature range of 600-900 °C for 30, 60, and 90 min. The modern technique of impulse excitation of vibration was used to analyze the elastic properties of bimetal, obtaining the temperature and time characteristics of Young's modulus, internal friction, and resonance frequency variability. Subsequently, the samples were stretched to breakage, obtaining information on the values of limit stresses, their deformability, and the energy demand for uniform elastic-plastic deformation in terms of the effect of temperature and annealing time. The influence of thermal processes on the strengthening of the Ti/Cu bimetal was also examined, and microscopic observations and qualitative analysis of the diffusion zone at the interface of the phases were carried out. The research was to answer the question of how a short-term temperature increase in 600-900 °C affects the physical properties of Ti/Cu bimetallic rods. These rods were used as a high-density electric current carrier in metallurgical processes in environments of aggressive chemical compounds. Studies have shown that short-term annealing at elevated temperatures causes a drastic reduction in the strength of the Ti/Cu bimetal, leading to structural changes within the components, and the diffusion zone with the release of intermetallic compounds, leading to structural degradation. Heating at 900 °C for 60 and 90 min caused accelerated interface degradation and destruction of the Ti/Cu bimetal by delamination.

Evaluation of a Long-Term Thermal Load on the Sealing Characteristics of Potential Sediments for a Deep Radioactive Waste Disposal

An in situ and a batch heating experiment were applied on the fine-grained sediments of the Opalinus Clay from Mont Terri (Switzerland) and the Boom Clay of Mol (Belgium), both being currently studied as potential host formations for deep nuclear waste disposal. The purpose was here to test the impact of a 100 °C temperature rise that is expected to be produced by nuclear waste in deep repositories. The experiment on the Opalinus Clay mimicked real conditions with 8-months operating heating devices stored in core drillings into the rock. The comparison of the major, trace, rare-earth elemental contents and of the whole-rock K-Ar data before and after heating shows only a few variations beyond analytical uncertainty. However, the necessary drillings for collecting control samples after the experiment added an unexpected uncertainty to the analyses due to the natural heterogeneity of the rock formation, even if very limited. To overcome this aspect, Boom Clay ground material was subjected to a batch experiment in sealed containers during several years. The drawback being here the fact that controls were limited with, however, similar reproducible results that also suggest limited elemental transfers from rock size into that of the &lt;2 μm material, unless the whole rocks lost more elements than the fine fractions. The analyses generated by the two experiments point to identical conclusions: a visible degassing and dewatering of the minerals that did not induce a visible alteration/degradation of the host-rock safety characteristics after the short-term temperature increase.

Long-Term Warming and Nitrogen Addition Regulate Responses of Dark Respiration and Net Photosynthesis in Boreal Bog Plants to Short-Term Increases in CO2 and Temperature

Boreal bog plants adapted to cold and low available nutrient conditions might be strongly affected by global changes, including elevated CO2 (eCO2), warming (W), and increasing nitrogen (N) availability. Here, we examined responses of dark respiration (Rd) and net photosynthesis (Anet) in four dominant bog plants to five levels of short-term increases in both CO2 and temperature (CTI); and the effects of long-term (6 years) W and N addition on these responses. Results indicated that CTI increased Rd; meanwhile, the increase of these environmental variables decreased Anet in all these boreal bog plants. Long-term nitrogen addition simulated the increases of Rd and decreases of Anet in Trichophorum cespitosum. Long-term warming mitigated the increases of Rd in Andromeda glaucophylla and Gaylussacia bigeloviana, and the decrease of Anet in Gaylussacia bigeloviana. These findings highlight the importance of long-term warming and nitrogen addition in regulating responses of boreal bog plants to short-term CTI, suggesting the necessity to investigate the long-term effects of these environmental changes when projecting responses of boreal bog vegetation to global changes.

Temperature effects on teleost immunity in the light of climate change.

Temperature is an important environmental modulator of teleost immune activity. Susceptibility of teleosts to temperature variation depends on the species-specific adaptive temperature range, and the activity of the teleost immune system is generally temperature-dependent. Similar to many physiological and metabolic traits of ectotherms, temperature modulates the activity of immune traits. At low temperatures, acquired immunity of many teleost species is down-modulated, and their immuno-competence mainly depends on innate immunity. At intermediate temperatures, both innate and acquired immunity are fully active and provide optimal protection, including long-lasting immunological memory. When temperatures increase and reach the upper permissive range, teleost immunity is compromised. Moreover, temperature shifts may have negative effects on teleost immune functions, in particular if shifts occur rapidly with high amplitudes. On the contrary, short-term temperature increase may help teleost immunity to fight against pathogens transiently. A major challenge to teleosts therefore is to maintain immuno-competence throughout the temperature range they are exposed to. Climate change coincides with rising temperatures, and more frequent and more extreme temperature shifts. Both are likely to influence the immuno-competence of teleosts. Nonetheless, teleosts exist in habitats that differ substantially in temperature, ranging from below zero in the Arctic's to above 40°C in warm springs, illustrating their enormous potential to adapt to different temperature regimes. The present review seeks to discuss how changes in temperature variation, induced by climate change, might influence teleost immunity.

Wind-driven retreat of cold water pool and abrupt sea temperature rise off the southwest coast of Korea in summer 2017

Variations in seawater temperature have a critical influence on marine ecosystems and aquaculture industries in coastal regions. From July 25 to August 5, 2017, the sea surface temperature off the southwestern coast of Korea rose rapidly from 17.1 °C to 27.3 °C, which induced environmental stress in marine organisms such as farmed abalone. This study investigated the cause of this abrupt sea temperature rise. Westerly winds from July 1 to 25 were favorable for the upwelling of cold subsurface water along the bottom slope in this coastal region, helping maintain cool surface water temperatures. As the wind changed to easterly, the cold subsurface water moved away and warmer, fresher surface water moved into the coastal region, where the surface currents changed from a southeastward flow to a northeastward flow from July 25 to August 5. Thus, to maintain stable, cool seawater temperatures during summer, both cold water supply and upwelling wind conditions are essential. The analysis of water masses indicated that the cold water was formed by the mixing of the Tsushima Warm Current Water and Yellow Sea Bottom Water in the northern East China Sea. The cold water advected eastward and formed a cold water pool in the intermediate depths (30–80 m) of the northern Jeju Strait, providing cold water to the coastal region during the upwelling period. The westerly winds were disrupted by the approach of a typhoon, which discontinued the supply of bottom cold water. The physical processes identified in this study will help predict short-term increases in water temperature and can assist in the development of countermeasures for the aquaculture industry against the negative effects of abrupt environmental changes.

Short-term exposure to heatwave-like temperatures affects learning and memory in bumblebees.

Global warming has been identified as a key driver of bee declines around the world. While it is clear that elevated temperatures during the spring and summer months—the principal activity period of many bee species—is a factor in this decline, exactly how temperature affects bee survival is unknown. In vertebrates, there is clear evidence that elevated ambient temperatures impair cognition but whether and how heat affects the cognitive abilities of invertebrates remains unclear. Cognitive skills in bees are essential for their survival as, to supply the hive with nutrition, workers must be able to learn and remember the location of the most rewarding floral resources. Here, we investigate whether temperature‐related cognitive impairments could be a driver of bee declines by exploring the effect of short‐term increases in ambient temperature on learning and memory. We found that, in comparison to bees that were tested at 25°C (a temperature that they would typically experience in summer), bees that were exposed to 32°C (a temperature that they will becoming increasingly exposed to during heatwave events) were significantly worse at forming an association between a coloured light and a sucrose reward and that their capacity to remember this association after just 1 h was abolished. This study provides novel experimental evidence that even just a few hours of exposure to heatwave‐like temperatures can severely impair the cognitive performance of insects. Such temperature‐induced cognitive deficits could play an important role in explaining recent and future bee population declines.

Evaluation of Selected Thermal Changes in Textile Materials Arising in the Wake of the Impact of Heat Radiation

The detection of changes in the morphological and chemical structure of four cotton/polyester blend fabrics and their constituent fibres caused by thermal radiation was the purpose of the study. Relatively short exposure times, i.e., 20 s, 25 s, 30 s and 40 s, of fabrics for an incident heat flux density of 10 kW/m2 were applied so that they did not cause changes visible to the naked eye. Such experimental conditions have been selected to resemble the ones that may occur during firefighting, rescue operations, some professional activities as well as during criminal events. The assumption that using the sequence of physicochemical methods, i.e., optical microscopy, scanning electron microscopy and FTIR spectroscopy, will make it possible to identify selected thermal changes in examined materials caused by a short-term temperature increase has been positively verified. Out of applied techniques, scanning electron microscopy showed the highest efficiency in tracking morphological changes in fibres occurring under the influence of heat radiation, while the FTIR method allows for the identification of thermal changes in the chemical structure of cotton fibres. Optical microscopic methods were also characterised by relatively high usefulness in the detection of thermal changes, especially in terms of the physical microstructure of PES fibres. The changes occurring in the fibres due to the action of heat radiation depend not only on the thermal behaviour of a particular type of fibre but also on the structural parameters of the examined textiles, i.e., porosity, and the mutual position of particular types of fibres in the three-dimensional structure of yarns and fabrics. Moreover, the studies revealed the presence of tiny, deformed balls at the ends of the thermoplastic fibres, visible on the surface of some original polyester-cotton textiles, caused by a singeing technological process, which should be taken into account during interpretation of analytical findings.

Embodied carbon assessment using a dynamic climate model: Case-study comparison of a concrete, steel and timber building structure

The enormous environmental impact of construction is becoming increasingly apparent and unacceptable to many structural engineers, whose designs typically account for the majority of a building’s embodied carbon. It is timely, therefore, that consensus is forming around a methodology for calculating embodied carbon. This encourages the inclusion of all life cycle stages, from material production and construction, through use and eventual demolition, disposal and reuse. In practice, however, end-of-life processes are fraught with uncertainty and often ignored, despite the potentially large associated carbon fluxes. Further uncertainty exists when considering bio-based construction materials, which store carbon during use. There are no widely-accepted means of accounting for timing of these carbon fluxes, despite the long service life of most buildings. Could we consider whole-life carbon in a more holistic and climate-focused way?This article uses dynamic life cycle assessment to convert greenhouse gas emission histories to key climate impacts using a simple dynamic model. The implications for structural design decisions are explored by comparing concrete, steel and timber options for a typical medium-rise building structure. Concrete is found to have a higher impact than steel, with the climate response of both options dominated by the large initial emissions of material production and construction. Timber has the smallest impact, for this example, under a typical scenario with sustainable forest management and re-emission of sequestered carbon at end-of-life. The analysis takes a forward-looking approach to sequestration, with timing corresponding to the growth of replanted trees. An optimistic timber scenario, whereby future carbon-capture technology avoids most end-of-life emissions, demonstrates the possibility of structures with small long-term climate cooling effects. Conversely, in a hypothetical worst-case scenario where no replanting or subsequent sequestration occurs, the long-term warming effect of the timber structure is increased by the net emission of biogenic carbon.Although end-of-life processes are important in the long-term, particularly for timber, the analysis also highlights the importance of the initial emissions from material production and construction. These cause high rates of short-term temperature increase and prolonged accumulation of radiative heat for all the buildings, but the impacts are again lowest for timber.Most importantly, the investigation shows how dynamic life cycle assessment can be used to explore climate impacts in a comprehensive, graphical and unbiased way. As a simple extension to established methodologies for calculating embodied carbon, it is a powerful decision making tool in the climate emergency.

Short- and long-term responses of photosynthetic capacity to temperature in four boreal tree species in a free-air warming and rainfall manipulation experiment.

High latitude forests cope with considerable variation in moisture and temperature at multiple temporal scales. To assess how their photosynthetic physiology responds to short- and long-term temperature variation, we measured photosynthetic capacity for four tree species growing in an open-air experiment in the boreal-temperate ecotone `Boreal Forest Warming at an Ecotone in Danger' (B4WarmED). The experiment factorially manipulated temperature above- and below-ground (ambient, +3.2°C) and summer rainfall (ambient, 40% removal). We measured A/Ci curves at 18, 25 and 32°C for individuals of two boreal (Pinus banksiana Lamb., Betula papyrifera Marsh.) and two temperate species (Pinus strobus L., Acer rubrum L.) experiencing the long-term warming and/or reduced-rainfall conditions induced by our experimental treatments. We calculated the apparent photosynthetic capacity descriptors VCmax,Ci and Jmax,Ci and their ratio for each measurement temperate. We hypothesized that (i) VCmax,Ci and Jmax,Ci would be down-regulated in plants experiencing longer term (e.g., weeks to months) warming and reduced rainfall (i.e., have lower values at a given measurement temperature), as is sometimes found in the literature, and that (ii) plants growing at warmer temperatures or from warmer ranges would show greater sensitivity (steeper slope) to short-term (minutes to hours) temperature variation. Neither hypothesis was supported as a general trend across the four species, as there was not a significant main effect (across species) of either warming or rainfall reduction on VCmax,Ci and Jmax,Ci. All species markedly increased VCmax,Ci and Jmax,Ci (and decreased their ratio) with short-term increases in temperature (i.e., contrasting values at 18, 25 and 32°C), and those responses were independent of long-term treatments and did not differ among species. The Jmax,Ci:VCmax,Ci ratio was, however, significantly lower across species in warmed and reduced rainfall treatments. Collectively, these results suggest that boreal trees possess considerable short-term plasticity that may allow homeostasis of VCmax,Ci and Jmax,Ci to a longer term temperature treatment. Our results also caution against extrapolating results obtained under controlled and markedly contrasting temperature treatments to responses of photosynthetic parameters to more modest temperature changes expected in the near-term with climate warming in field conditions.

Short-Term Exposure to High-Temperature Water Causes a Shift in the Microbiome of the Common Aquarium Sponge Lendenfeldia chondrodes

Marine sponges harbor diverse microbiomes that contribute to their energetic and metabolic needs. Although numerous studies on sponge microbial diversity exist, relatively few focused on sponge microbial community changes under different sources of environmental stress. In this study, we assess the impact of elevated seawater temperature on the microbiome of cultured Lendenfeldia chondrodes, a coral reef sponge commonly found in marine aquaria. Lendenfeldia chondrodes exhibits high thermal tolerance showing no evidence of tissue damage or bleaching at 5 °C above control water temperature (26 °C). High-throughput sequencing of the bacterial 16S rRNA V4 region revealed a response of the microbiome of L. chondrodes to short-term exposure to elevated seawater temperature. Shifts in abundance and richness of the dominant bacterial phyla found in the microbiome of this species, namely Proteobacteria, Cyanobacteria, Planctomycetes, and Bacteroidetes, characterized this response. The observed resilience of L. chondrodes and the responsiveness of its microbiome to short-term increases in seawater temperature suggest that this holobiont may be capable of acclimating to anthropogenic-driven sublethal environmental stress via a re-accommodation of its associated bacterial community. This sheds a new light on the potential for resilience of some sponges to increasing surface seawater temperatures and associated projected regime shifts in coral reefs.

Gut microbiota of invasive bullfrog tadpoles responds more rapidly to temperature than a noninvasive congener

Environmental temperature can alter the composition, diversity, and function of ectothermic vertebrate gut microbial communities, which may result in negative consequences for host physiology, or conversely, increase phenotypic plasticity and persistence in harsh conditions. The magnitude of either of these effects will depend on the length of time animals are exposed to extreme temperatures, and how quickly the composition and function of the gut microbiota can respond to temperature change. However, the temporal effects of temperature on gut microbiota are currently unknown. Here, we investigated the length of time required for increased temperature to alter the composition of gut bacterial communities in tadpoles of two frog species, the green frog, Lithobates clamitans, and its congener, the globally invasive American bullfrog, L.catesbeianus. We also explored the potential functional consequences of these changes by comparing predicted metagenomic profiles across temperature treatments at the last experimental time point. Bullfrog-associated microbial communities were more plastic than those of the green frog. Specifically, bullfrog communities were altered by increased temperature within hours, while green frog communities took multiple days to exhibit significant changes. Further, over ten times more bullfrog bacterial functional pathways were temperature-dependent compared to the green frog. These results support our hypothesis that bullfrog gut microbial communities would respond more rapidly to temperature change, potentially bolstering their ability to exploit novel environments. More broadly, we have revealed that even short-term increases in environmental temperature, expected to occur frequently under global climate change, can alter the gut microbiota of ectothermic vertebrates.

E. coli production process yields stable dengue 1 virus-sized particles (VSPs)

Dengue fever is one of the most wide-spread vector-borne diseases in the world. Although dengue-associated mortality is low, morbidity and economic impact are high. Current licensed vaccines are limited and mediate only partial protection, thus a cost-effective vaccine with improved efficacy is strongly needed.In this work, recombinant dengue serotype 1 E protein was produced in E. coli, inclusion bodies were isolated and the E protein solubilized in urea and purified using an immobilized metal chelate affinity column. The protein was refolded by dialysis in order to obtain virus-like particles (VLPs).Particle assembly was confirmed using size-exclusion chromatography, dynamic light scattering (DLS), transmission electron microscopy (TEM), atomic force microscopy and stimulated emission depletion fluorescence (STED) microscopy. Particle diameter was strongly dependent on temperature, pH, buffer salt composition, and addition of L-arginine. Particles were stable in carbonate buffer at pH 9.5 and higher at 4 °C and did not aggregate during short-term temperature increase up to 55 °C.However, on basis of the above analyses, especially the results of DLS, TEM and STED, it was concluded that the particles obtained did not have an optimal virus-like structure and were therefore designated “virus-sized particles” (VSPs) rather than VLPs.Immunization of rabbits with the particles did not induce neutralizing antibodies, despite the recognition of the native virus by rabbit antibodies. As the titers against the immunogen were much higher than against the (heat-inactivated) virus, it is assumed that the conformation of the particles at the time of immunization was not optimal. Studies are currently underway to improve the quality of the E protein virus-sized particles towards true virus-like particles in order to optimize its potential as a dengue vaccine candidate.

Short-term testicular warming under anesthesia causes similar increases in testicular blood flow in Bos taurus versus Bos indicus bulls, but no apparent hypoxia

Bull testes must be 4–5 °C below body temperature, with testicular warming more likely to cause poor-quality sperm in Bos taurus (European/British) versus Bos indicus (Indian/zebu) bulls. Despite a long-standing dogma that testicular hyperthermia causes hypoxia, we reported that increasing testicular temperature in bulls and rams enhanced testicular blood flow and O2 delivery/uptake, without hypoxia. Our objective was to determine effects of short-term testicular hyperthermia on testicular blood flow, O2 delivery and uptake and evidence of testicular hypoxia in pubertal Angus (B. taurus) and Nelore (B. indicus) bulls (nine per breed) under isoflurane anesthesia. As testes were warmed from 34 to 40 °C, there were increases (P < 0.0001, but no breed effects) in testicular blood flow (mean ± SEM, 9.59 ± 0.10 vs 17.67 ± 0.29 mL/min/100 g, respectively), O2 delivery (1.79 ± 0.06 vs 3.44 ± 0.11 mL O2/min/100 g) and O2 consumption (0.69 ± 0.07 vs 1.25 ± 0.54 mL O2/min/100 g), but no indications of testicular hypoxia. Hypotheses that: 1) both breeds increase testicular blood flow in response to testicular warming; and 2) neither breed has testicular hypoxia, were supported; however, the hypothesis that the relative increase in blood flow is greater in Angus versus Nelore was not supported. Although these were short-term increases in testicular temperature in anesthetized bulls, results did not support the long-standing dogma that increased testicular temperature does not increase testicular blood flow and an ensuing hypoxia is responsible for decreases in motile, morphologically normal and fertile sperm.

Broad Thermal Tolerance in the Cold-Water Coral Lophelia pertusa From Arctic and Boreal Reefs.

Along the Norwegian coasts and margins, extensive reefs of the stony coral Lophelia pertusa act as hotspots for local biodiversity. Climate models project that the temperature of Atlantic deep waters could rise by 1–3°C by 2100. In this context, understanding the effects of temperature on the physiology of cold-water species will help in evaluating their resilience to future oceanic changes. We investigated the response of L. pertusa to stepwise short-term increases in temperature. We sampled corals from four reefs, two located north of the Arctic circle and two at the mid-Norwegian shelf (boreal). In on-board experiments (one per reef), the sampled fragments were exposed to increasing temperatures from 5 to 15°C over 58 h. Respiration increased linearly by threefold for a 10°C increase. The short-term temperature increase did not induce mortality, cellular (neutral red assay for lysosome membrane stability; but one exception) or oxidative stress (lipid peroxidation assay) – to a few exceptions. However, the variability of the respiration responses depended on the experiment (i.e., reef location), possibly linked to the genetic structure of the individuals that we sampled (e.g., clones or siblings). The corals from the Arctic and boreal regions appear to have a high tolerance to the rapid temperature fluctuations they experience in the field. Over extended periods of time however, an increased metabolism could deplete the energy stored by the corals, if not met by an increased food availability and/or uptake. Empirical data on organisms’ thermal performance curves, such as the one presented in this study for L. pertusa, will be useful to implement predictive models on the responses of species and populations to climate change.