Coral bleaching, i.e. the loss of photosynthetic algal symbionts, caused by ocean warming is now the main factor driving reef decline, but not all corals are affected equally. Corals from the Arabian Seas have unusually high temperature tolerances, and recently studies implicated salinity as one of the contributing factors. In particular, a recent heat stress experiment at different salinities using the model system Aiptasia and Red Sea corals, showed that cnidaria at large bleach less at heat stress under high salinities and that this is associated with an increase of the osmolyte, floridoside Here we were interested to assess microbial community changes under heat stress at different salinity levels and whether this could help to explain the increase in thermal tolerance of the metaorganism at high salinities. We determined microbial community composition via HiSeq 16S rRNA gene amplicon sequencing of two anemone strains that differ in their associated symbionts, namely H2-SSB01 (type B1) and CC7-SSA01 (type A4), after six days under ambient (25 °C) and heat stress (34 °C) temperatures at salinities of 36, 39, and 42. Both anemones harbored distinct microbial communities, irrespective of temperature or salinity, that were also different from the bacteria in surrounding seawater. Within both host-endosymbiont pairings, the bacterial community composition at low (36) and intermediate (39) salinities did not differ between ambient and heat stress, but was significantly different at high (42) salinities. Subsequent elucidation of bacterial indicator species revealed several taxa that could be associated with a response to temperature and salinity. Our results underline that microbial community composition adjusts under different environmental settings. Importantly, microbial community dynamics of H2-SSB01 aligned with observed differences in bleaching susceptibility and thermal tolerance, whereas the pattern remains unclear for CC7-SSA01, which harbors an intrinsically higher thermal tolerance. Such responses could argue for a contribution of the microbiome to the observed increase in temperature tolerance of the Aiptasia metaorganism at increased salinities. An alternative interpretation is that the microbiome changes denotes a parallel response to changing salinities.

Drought and temperature stress are the two most important factors limiting crop productivity. A physiological and proteomic analysis of soybean was performed to investigate the negative impact of these variables. The previous studies reported the beneficial effect of silicon under stress conditions. Silicon supplementation may promote plant growth under drought stress, although the mechanism to alleviate drought stress is uncertain. The proteomic analysis of chloroplast proteins was carried out to study the response of silicon supplementation under drought stress. Similarly, temperature stress, mainly heat stress, has an adverse effect on soybean plants. The comparative analysis of two soybean cultivars, DS25-1 and DS31-243 was examined under ambient and elevated CO2 levels. The proteomic study employed two-dimensional gel analysis and mass spectrometry techniques to identify differentially expressed proteins under drought and temperature stress. The identified proteins are involved in metabolic processes, photosynthesis, signaling, redox homeostasis, and other cellular pathways. Most of these proteins were involved in metabolism, response to heat and photosynthesis showing significant cross-tolerance mechanisms. The physiological parameters like stomatal conductance, transpiration, photosynthesis, and chlorophyll pigments were also studied. Silicon application improved plant growth under drought stress. However, at the elevated CO2 level, plants showed better growth under heat stress. Together, these findings suggested the role of silicon and elevated CO2 concentration in drought and temperature stress in soybean. The differentially expressed proteins helped mitigate the negative impact of these stress, mainly the photosynthetic, antioxidant and heat shock proteins, and enhance crop growth and productivity under drought and heat stress.

Previous findings showed that Listeria monocytogenes exhibits higher heat tolerance to thermal exposure at 60°C when pre-exposed to sublethal heat stress at 48°C for 30/60 min. The objective of this study was to investigate the morphological changes that occurred in L. monocytogenes serotype 1/2a cells as visualized by transmission electron microscopy (TEM) after exposure to sublethal heat stress at 48°C for 60 min and in combination with lethal concentration of carvacrol for 30 min. The TEM micrographs revealed thickening of cell wall and cell membrane, and clumping of cytoplasm when subjected to sublethal heat stress followed by carvacrol treatment. These studies indicate that L. monocytogenes cells when adapted to heat stress may alter its morphology to protect themselves against carvacrol. Further studies will investigate the effect of increased contact time with carvacrol and with other essential oils on the ultrastructural changes in L. monocytogenes cells adapted to heat stress.

The objective of this study was to investigate the differences in survival of L. monocytogenes EGD (Bug600) (serotype 1/2a) in various disinfectants and essential oils after sublethal heat stress at 48°C for 60 min. The survival of heat stressed L. monocytogenes cells was decreased in lethal acid (HCl or H3PO4 pH 2.5), lethal oxidative stress (H2O2 1000 ppm) and lethal quaternary ammonium compounds (QAC 2.5-3.5 ppm) compared to non-stressed control cells. By contrast, the survival of heat stressed L. monocytogenes cells was higher in lethal alkali (NaOH or KOH pH 12) than the control cells. Also, the survival of heat stressed L. monocytogenes cells was higher in lethal carvacrol (428 ppm) and bay oil (1100 ppm) but was decreased in lethal red thyme oil (300 pm) compared to control. These findings indicate that the heat stressed cells of L. monocytogenes are not easily killed by alkali-based disinfectants and essential oils containing carvacrol and bay oil. Therefore, disinfectants and essential treatments should be carefully considered when heat stressed cells of L. monocytogenes may be present.

Abiotic stress tolerance and biotic stress resistance have long been targets for trait improvement in the field of plant breeding. To date, much of the target crop focus has been centered on commodity crops such as corn, soybean, wheat, and rice. However, little work has been conducted on improvement of these traits in forage grasses. This is due to a number of issues, particularly that most species are obligately outcrossing, the traits are governed by many genes at unknown loci, and are greatly affected by environmental variation. This creates major complications in successfully selecting and breeding populations of forage grasses tolerant to extreme high or low temperatures, as well as disease resistance. Recurrent phenotypic selection was used to select elite individuals of annual ryegrass (Lolium multiflorum Lam.) and orchardgrass (Dactylis glomerata L.) that expressed improved germination at high temperature. Selections were conducted within growth chambers at fixed temperature and light regimes (40/30 DEGREES C, 12/12 hr, light/darkness) to eliminate environmental variation. Following three cycles of selection, we observed gains (P LESSTHAN 0.001) in selection over the base population for both species. Annual ryegrass mean cumulative germination for cycle 3 peaked at 45.8%, and orchardgrass mean cumulative germination for cycle 3 peaked at 82.67%. Further selection of annual ryegrass for freezing tolerance was also conducted. Flats of unselected germplasm were grown to the three-leaf stage, then frozen for nine hours. Significant differences (P LESSTHAN 0.05) in freezing tolerance were observed between selected germplasm in both cycle 1 (0.076%) and cycle 2 (0.125%) over the unselected cycle 0 (0.025%). Finally, initial stages of resistance breeding work were conducted involving gray leaf spot (causal agent Pyricularia grisea Cke. [Sacc.]) on annual ryegrass. Isolates of the pathogen were obtained and stored for future use. It was determined that the actual pathogen species responsible was Pyricularia oryzae Cavara. Future work for annual ryegrass and orchardgrass germplasm that germinates at high temperatures will involve variety testing and cultivar release. Freezing tolerance and disease resistance work will require larger-scale screening methodology that was able to be conducted in this work to acquire sufficient population sizes for breeding.

The primary goals of this research were to develop an improved design for measuring tympanic temperature in groups of beef cattle, determine the ideal operating parameters of the new device, and to verify its effectiveness in a research application. Development of the continuous tympanic temperature logger (CTTL) consisted of two steps: identifying a small temperature logger capable of adequate data storage and constructing a probe to hold the logger and fit in the ear canal of a bovine animal. The minimum sampling interval needed to measure tympanic temperature in beef cattle was calculated using Fourier analysis. In addition, the differences in core body temperature between three measurement locations (left ear, right ear, and vagina) were quantified. The CTTL was also used to record the thermoregulatory responses of feedlot heifers with access to shade provided by three different materials.

Objective 1 was to investigate effects of heat stress and breed on milk and component yield for Holstein and Jersey cows on the same farm. Objective 2 was to determine the effects of breed on udder health as measured by somatic cell count (SCC) during times of heat stress. Data were collected from DHIA records of 142 Jersey cows and 586 Holstein cows from the University herd at Mississippi State University. During heat stress Jersey milk yield and 4% fat corrected milk (FCM) increased (P<0.01). Holstein milk yield and FCM decreased during heat stress (P<0.01). Heat stress affected somatic cell count (SCC) although effects varied by intensity of heat stress. Breed did not have an affect on SCC. Milk fat and protein percentages declined for both breeds in heat stress conditions. Milk fat but not milk protein of Jersey cows increased as stress increased from mild to severe.

In vitro and animal studies indicate that the response to heat stress is associated with beneficial adaptations that promote cell health and survival. Few studies to date have examined this finding in human subjects, and it is unclear how the adaptation compares in magnitude to exercise training. The purpose of this study was to investigate the skeletal muscle adaptations (namely mitochondrial biogenesis and capillarization) of 6 weeks of deep-muscle heat treatment relative to exercise training. We hypothesized that heat treatment (HT), applied through pulsed shortwave diathermy (2 hr, 3 days/week) over a 6-week intervention period would lead to increased mitochondrial content and capillarity within skeletal muscle, though to a lesser extent than single-leg knee extension exercise training (EX; 40 min, 3 days/week). We randomized 28 sedentary but otherwise healthy, young adults (ages 18–36; n = 13 female, n = 15 male) to receive either HT, EX, or sham heating sessions (CON; 2 hr, 3 days/week) over 6 weeks. Diathermy increased muscle temperature by 3.2 ± 0.33 C (P < 0.0001) within 20 minutes. Muscle biopsies were taken from the vastus lateralis at baseline, after 3 weeks of intervention and again after 6 weeks of intervention. Following 3 and 6 weeks of heat treatment, we did not observe significant changes in mitochondrial biogenesis or capillarization. However, exercise training was sufficient to elicit an increase in individual capillary-to-fiber ratio (P = 0.0003), capillary density (P = 0.0428), and the Capillary to Fiber Perimeter Exchange Index (P = 0.0089). Significant increases in the expression of mitochondrial protein Complexes I (P = 0.0073) and IV (P = 0.0015), were observed in the exercise group, but not the heat or control groups. These results indicate that 6 weeks of localized HT, when applied to young healthy individuals, is insufficient to induce mitochondrial biogenesis or capillarization in skeletal muscle. Additionally, our findings provide support for the extensive body of literature that connect exercise training to beneficial skeletal muscle adaptations.

The sea squirts Ciona intestinalis and C. savignyi have disparate distribution patterns, which may result from differences in their thermal tolerance limits. Because C. intestinalis, an almost cosmopolitan species, has a more widespread distribution, it is thought that it is better adapted to endure a wide range of temperatures. In order to compare the heat stress response between these two congeners, we studied global changes in protein expression, using a proteomics approach. To characterize the response to extreme heat stress, animals of both species were exposed to temperatures of 22°C, 25°C, and 28°C for 6 h, and then were left to recover at a control temperature (13°C) for 16 h. An additional experiment was conducted to assess the effect of mild-to-moderate heat stress including a 6 h exposure to temperatures of 18°C, 20°C, and 23°C, and a 16 h recovery at a control temperature (16°C). A quantitative analysis, using 2D gel electrophoresis and gel-image analysis, showed that in the high heat stress (HHS) experiment, 15% and 18% of the all protein spots detected demonstrated changes in expression in C. intestinalis and C. savignyi, respectively. In the low heat stress (LHS) experiment, 4% of the total number of proteins detected changed significantly in both C. intestinalis and C. savignyi. Using matrix-assisted laser desorption ionization (MALDI) tandem time-of-flight mass spectrometry, we were able to identify proteins with a 65-100% success rate, depending on species. Our results indicate that C. intestinalis maintains higher baseline levels of molecular chaperones and launches a quicker response to thermal stress than C. savignyi, suggesting it may be the more thermally tolerant of the two. In addition, actins, tubulins, and ATP-synthase F1 β-subunits were the most susceptible to proteolytic degradation, which may indicate that they have relatively higher thermal sensitivities.

Increases in seawater temperatures have imposed physiological constraints which are partially thought to contribute to recently observed shifts in biogeographic distribution among closely related intertidal ectotherms. For instance, Mytilus galloprovincialis an introduced warm-adapted species from the Mediterranean, has displaced the native cold-adapted congener, M. trossulus, over large latitudinal expanses off the California coast. Several comparative physiological studies have revealed interspecific differences in thermal tolerance, including variation in aerobic metabolism and gape behavior, which suggest the invasive congener is better adapted to acclimate to increasing seawater conditions as predicted due to climate change. However, current analyses seek to discover the cellular process which contribute to thermal plasticity at the level of the whole organism in response to temperature stress. Since proteins represent the primary molecular machinery capable of responding to thermal stress, we quantified the proteomic response of the adductor muscles (AM) of M. galloprovincialis and M. trossulus to acute heat stress. After acclimation to 13°C, we exposed mussels to 24°C, 28°C and 32 °C (at a heating rate of 6C/h), kept mussels at the temperature for 1 h and then added a 24-h recovery period. Posterior adductor muscle samples were then excised and utilized for proteomic analysis. We were able to detect 273 protein spots within M. galloprovincialis and 286 protein spots within M. trossulus. Roughly 33% of these protein spots exhibited significant changes in abundance in response to heat stress within M. trossulus as compared to only 19% in M. galloprovincialis. In both data sets, most proteins changing abundance are part of the cytoskeleton or proteins controlling actin thin filament dynamics and stress fiber formation. Specifically, M. galloprovincialis increased the abundance of proteins involved in thin filament stabilization and cytoskeletal maintenance. In contrast, M. trossulus increased proteins involved in thin filament destabilization and filament turnover. In addition, only M. trossulus increased proteins involved in the cellular stress response at the highest temperature, suggesting its AM proteome is more thermolabile. In return, our results suggest that cytoskeletal architecture is more thermally stable in M. galloprovincialis. The differences in the proteomic responses suggest that M. galloprovincialis is capable of protecting itself from heat stress through valve closure at a higher temperature due to the increase in actin stabilizing proteins.