Functional and physiological consequences of genetic variation at phosphoglucose isomerase: Heat shock protein expression is related to enzyme genotype in a montane beetle

Allele frequency variation at the phosphoglucose isomerase (PGI) locus in Californian populations of the beetle Chrysomela aeneicollis suggests that PGI may be undergoing natural selection. We quantified (i) apparent Michaelis-Menten constant (Km) of fructose 6-phosphate at different temperatures and (ii) thermal stability for three common PGI genotypes (1–1, 1–4, and 4–4). We also measured air temperature (Ta) and beetle body temperature (Tb) in three montane drainages in the Sierra Nevada, California. Finally, we measured 70-kDa heat shock protein (Hsp70) expression in field-collected and laboratory-acclimated beetles. We found that PGI allele 1 predominated in the northernmost drainage, Rock Creek (RC), which was also significantly cooler than the southernmost drainage, Big Pine Creek (BPC), where PGI allele 4 predominated. Allele frequencies and air temperatures were intermediate in the middle drainage, Bishop Creek (BC). Differences among genotypes in Km (1–1 > 1–4 > 4–4) and thermal stability (4–4 > 1–4 > 1–1) followed a pattern consistent with temperature adaptation. In nature, Tb was closely related to Ta. Hsp70 expression in adult beetles decreased with elevation and differed among drainages (BPC > BC > RC). After laboratory acclimation (8 days, 20°C day, 4°C night) and heat shock (4 h, 28–36°C), Hsp70 expression was greater for RC than BPC beetles. In RC, field-collected beetles homozygous for PGI 1–1 had higher Hsp70 levels than heterozygotes or a 4–4 homozygote. These results reveal functional and physiological differences among PGI genotypes, which suggest that montane populations of this beetle are locally adapted to temperature.

Biological clocks

Circadian rhythms describe biological phenomena that oscillate with an ≈24-hour cycle. These rhythms include blood pressure, body temperature, hormone levels, the number of immune cells in blood, and the sleep-wake cycle. In this paper, we will focus on common genes between species that are responsible for determining the circadian behavior, especially some transcription factors (i.e., switch genes) that serve to regulate many circadian rhythm genes. The intent of this summary is to introduce the common molecular mechanism of biological clocks between flies and humans and then to describe the research from three laboratories that was presented in the session.

Potentiation of capsaicin receptor activity by metabotropic ATP receptors as a possible mechanism for ATP-evoked pain and hyperalgesia

The capsaicin (vanilloid) receptor, VR1, is a sensory neuron-specific ion channel that serves as a polymodal detector of pain-producing chemical and physical stimuli. It has been proposed that ATP, released from different cell types, initiates the sensation of pain by acting predominantly on nociceptive ionotropic purinoceptors located on sensory nerve terminals. In this study, we examined the effects of extracellular ATP on VR1. In cells expressing VR1, ATP increased the currents evoked by capsaicin or protons through activation of metabotropic P2Y1 receptors in a protein kinase C-dependent pathway. The involvement of Gq/11-coupled metabotropic receptors in the potentiation of VR1 response was confirmed in cells expressing both VR1 and M1 muscarinic acetylcholine receptors. In the presence of ATP, the temperature threshold for VR1 activation was reduced from 42°C to 35°C, such that normally nonpainful thermal stimuli (i.e., normal body temperature) were capable of activating VR1. This represents a novel mechanism through which the large amounts of ATP released from damaged cells in response to tissue trauma might trigger the sensation of pain.

A mechanism for the inhibition of fever by a virus.

Poxviruses encode proteins that block the activity of cytokines. Here we show that the study of such virulence factors can contribute to our understanding of not only virus pathogenesis but also the physiological role of cytokines. Fever is a nonspecific response to infection that contributes to host defense. Several cytokines induce an elevation of body temperature when injected into animals, but in naturally occurring fever it has been difficult to show that any cytokine has a critical role. We describe the first example of the suppression of fever by a virus and the molecular mechanism leading to it. Several vaccinia virus strains including smallpox vaccines express soluble interleukin 1 (IL-1) receptors, which bind IL-1 beta but not IL-1 alpha. These viruses prevent the febrile response in infected mice, whereas strains that naturally or through genetic engineering lack the receptor induce fever. Repair of the defective IL-1 beta inhibitor in the smallpox vaccine Copenhagen, a more virulent virus than the widely used vaccine strains Wyeth and Lister, suppresses fever and attenuates the disease. The vaccinia-induced fever was inhibited with antibodies to IL-1 beta. These findings provide strong evidence that IL-1 beta, and not other cytokines, is the major endogenous pyrogen in a poxvirus infection.

Thermosensitive phenotype of transgenic mice overproducing human glutathione peroxidases.

Exposure of humans and other mammals to hyperthermic conditions elicits many physiological responses to stress in various tissues leading to profound injuries, which eventually result in death. It has been suggested that hyperthermia may increase oxidative stress in tissues to form reactive oxygen species harmful to cellular functions. By using transgenic mice with human antioxidant genes, we demonstrate that the overproduction of glutathione peroxidase (GP, both extracellular and intracellular) leads to a thermosensitive phenotype, whereas the overproduction of Cu,Zn-superoxide dismutase has no effect on the thermosensitivity of transgenic mice. Induction of HSP70 in brain, lung, and muscle in GP transgenic mice at elevated temperature was significantly inhibited in comparison to normal animals. Measurement of peroxide production in regions normally displaying induction of HSP70 under hyperthermia revealed high levels of peroxides in normal mice and low levels in GP transgenic mice. There was also a significant difference between normal and intracellular GP transgenic mice in level of prostaglandin E2 in hypothalamus and cerebellum. These data suggest direct participation of peroxides in induction of cytoprotective proteins (HSP70) and cellular mechanisms regulating body temperature. GP transgenic mice provide a model for studying thermoregulation and processes involving actions of hydroxy and lipid peroxides in mammals.

Conhecimento dos pais perante a criança com febre

Enquadramento – A febre na criança é reconhecida como uma manifestação de doença e encarada por muitos pais com uma conotação negativa, causando grande ansiedade e obsessão pela apirexia. Objetivos – Determinar o nível do conhecimento dos pais/acompanhantes perante a criança com febre; verificar se as variáveis sociodemográficas, contextuais da febre e de caraterização da criança interferem no conhecimento dos pais/acompanhantes perante a criança com febre. Métodos – Estudo quantitativo, transversal, descritivo e correlacional, realizado numa amostra não probabilística por conveniência, constituída por 360 pais/acompanhantes de crianças na consulta de Saúde Infantil, em instituições de saúde públicas, na região centro de Portugal. Recorreu-se a um questionário de autopreenchimento, com caracterização sociodemográfica, da febre, da criança e do conhecimento sobre a febre. Resultados – Amostra com idade média de 34.7 anos ± 7.9, maioritariamente feminina (51.7%). Com fracos conhecimentos perante a criança com febre prevalecem os participantes com idade ≥ 38 anos (36.2%), que coabitam com companheiro(a) (77.0%), em zona rural (69.3%) e com escolaridade até ao 3º ciclo (53.9%). Os participantes com idade até 37 anos (68,2%), com companheiro(a) (89.0%), residentes em zona urbana (53.0%) e com o ensino superior (43.3%) revelaram bons conhecimentos. As principais fontes de informação sobre a febre foram o médico (65.8%) e o enfermeiro (50.6%). As mulheres, os acompanhantes de crianças com menos idade e com melhores atitudes revelaram melhores conhecimentos perante a criança com febre. Conclusão: Os resultados apontam para a importância da realização de sessões de educação para a saúde aos pais/acompanhantes, de modo a aumentar o conhecimento perante a febre na criança. Palavras-chave: Conhecimento - Febre - Criança.

Masking odour when regrouping rabbit does: Effect on aggression, stress and lesions.

Regrouping female rabbits (Oryctolagus cuniculus) in group housing systems is a common management practice in Swiss rabbit breeding which may, however, induce agonistic interactions resulting in social stress and severe lesions. On farms using artificial insemination, does are usually kept singly for 12 days after parturition to avoid pseudopregnancy and fighting for nests. The integration of new group members usually occurs after this isolation phase. This study was conducted with 128 gravid does of the Hycole hybrid, housed in pens covering a floor area of 5.7 m2 that was bedded with straw and furnished with elevated areas, hiding places and eight compartments with nest boxes. In the experiment, the fur of 16 groups of 8 does each was sprayed with either alcohol or vinegar to mask the pre-existing group odours, or with water (control groups) shortly before regrouping. Lesion scores, stress parameters (body temperature and blood glucose level) and behaviour were assessed before and after the isolation phase. Effects of treatment and time on all collected parameters were analysed using mixed models. On the second day after regrouping 43% of the does showed new lesions. In the first five days after regrouping, new lesions occurred in 60% of the does; 32% had severe lesions. After regrouping, more agonistic interactions were observed and body temperature and blood glucose levels were higher than before regrouping (P<0.001 each). Body temperature increased less in groups treated with vinegar compared to the other two treatments on the first day after regrouping (P=0.017). In all other parameters no influence of the treatment with alcohol or vinegar was found. These findings suggest that masking the group odours with alcohol or vinegar had little effect on lesions, stress and agonistic interactions. Therefore, alternative management procedures need to be developed to reduce lesions and stress caused by aggressive behaviour.

An essay concerning the generation of heat in animals /

Mode of access: Internet.

Ueber das Verhalten der Körpertemperatur vor, während und nach der Geburt bei Pferd, Schwein und Hund ...

Lebenslauf.

Heat stress, heat strain, and productivity in Washington State tree fruit harvesters

Thesis (Master's)--University of Washington, 2016-06

The relationship between diurnal type and time duration estimation at morning and evening times of day

This study investigates whether different diurnal types (morning versus evening) differ in their estimation of time duration at different times of the day. Given that the performance of morning and evening types is typically best at their preferred times of day, and assuming different diurnal trends in subjective alertness (arousal?) for morning and evening types, and adopting the attentional gate model of time duration estimation, it was predicted that morning types would tend to underestimate and be more accurate in the morning compared to evening types where the opposite pattern was expected. Nineteen morning types, 18 evening types and 18 intermediate types were drawn from a large sample (N=1175) of undergraduates administered the Early/Late Preference Scale. Groups performed a time duration estimation task using the production method for estimating 20-s unfilled intervals at two times of day: 0800/1830. The median absolute error, median directional error and frequency of under- and overestimation were analysed using repeated-measures ANOVA. While all differences were statistically non-significant, the following trends were observed: morning types performed better than evening types; participants overestimated in the morning and underestimated in the evening; and participants were more accurate later in the day. It was concluded that the trends are inconsistent with a relationship between subjective alertness and time duration estimation but consistent with a possible relationship between time duration estimation and diurnal body temperature fluctuations. (C) 2002 Elsevier Ltd. All rights reserved.

Prostaglandins are important in thermoregulation of a reptile (Pogona vitticeps)

The effectiveness of behavioural thermoregulation in reptiles is amplified by cardiovascular responses, particularly by differential rates of heart beat in response to heating and cooling (heart-rate hysteresis). Heart-rate hysteresis is ecologically important in most lineages of ectothermic reptile' and we demonstrate that heart-rate hysteresis in the lizard Pogona vitticeps is mediated by prostaglandins. In a control treatment (administration of saline), heart rates during heating were significantly faster than during cooling at any given body temperature. When cyclooxygenase 1 and 2 enzymes were inhibited, heart rates during heating were not significantly different from those during cooling. Administration of agonists showed that thromboxane B-2 did not have a significant effect on heart rate, but prostacyclin and prostaglandin F-2alpha caused a significant increase (3.5 and 13.6 beats min(-1), respectively) in heart rate compared with control treatments. We speculate that heart-rate hysteresis evolved as a thermoregulatory mechanism that may ultimately be controlled by neurally induced stimulation of nitric oxide production, or maybe via photolytically induced production of vitamin D.

Physiological thermoregulation in a crustacean? Heart rate hysteresis in the freshwater crayfish Cherax destructor

Differential heart rates during heating and cooling (heart rate hysteresis) are an important thermoregulatory mechanism in ectothermic reptiles. We speculate that heart rate hysteresis has evolved alongside vascularisation, and to determine whether this phenomenon occurs in a lineage with vascularised circulatory systems that is phylogenetically distant from reptiles, we measured the response of heart rate to convective heat transfer in the Australian freshwater crayfish, Cherax destructor. Heart rate during convective heating (from 20 to 30 degreesC) was significantly faster than during cooling for any given body temperature. Heart rate declined rapidly immediately following the removal of the heat source, despite only negligible losses in body temperature. This heart rate 'hysteresis' is similar to the pattern reported in many reptiles and, by varying peripheral blood flow, it is presumed to confer thermoregulatory benefits particularly given the thermal sensitivity of many physiological rate functions in crustaceans. (C) 2004 Published by Elsevier Inc.

Cot-nursing using a heated, water-filled mattress and incubator care: a randomized clinical trial

Aims: To evaluate the thermal responses and weight gain in preterm infants nursed in a cot on a heated, water-filled mattress (HWM) compared with infants receiving care in an air-heated incubator and to compare mothers' stress, anxiety levels and perceptions of their infants in the two groups. Methods: Stable preterm infants weighing 1300 to 1500 g were enrolled, being randomly allocated to either the study group (n = 41) receiving care in a cot on an HWM, or the control group ( n = 33) receiving incubator care. The mean daily body temperature and episodes of cold stress and hyperthermia were recorded. Weight gain (g kg(-1) body weight d(-1)) was also calculated. The mothers completed questionnaires on their perceptions of their infants, and their anxiety and stress levels before randomization, and 2 - 3 wk later during the trial. Results: The mean body temperature was similar for the first week of the trial ( study group 36.9degreesC vs controls 36.9degreesC). There were no significant differences in the incidence of cold stress, while more hyperthermic episodes were seen in the study group ( p = 0.03). There were no significant differences in weight gain during the first ( study group 21.4 g vs controls 19.6 g) or second weeks of the trial ( study group 20.5 g vs controls 19.2 g). Neonatal morbidity did not differ between the groups. There were no differences in mothers' perceptions of their babies, or feelings of stress or anxiety. Conclusion: There were no differences between infants cot-nursed on an HWM and those receiving incubator care, with the exception of episodes of high temperature. The results suggest that the HWM may be used safely for low-weight preterm infants.

Wetting and the physiological responses of grain-fed cattle in a heated environment

A controlled crossover experimental design was used to determine the effect of altered water sprinkling duration on heifers subjected to heat stress conditions. Heifers were subjected to 3 days of thermoneutral conditions followed by 3 days of hot conditions accompanied by water sprinkling between 1300 and 1500 h (HOT1-3). Then on the following 2 days (HOT4-5), environmental conditions remained similar, but 3 heifers were sprinkled between 1200 and 1600 h ( WET) and 3 were not sprinkled (NONWET). This was followed by a 1-day period (HOT6) in which environmental conditions and sprinkling regimen were similar to HOT1-3. Rectal temperature (RT) was collected hourly, and respiration rate (RR) was monitored every 2 h on HOT Days 2, 4, 5, and 6. Dry matter intake and rate of eating were also determined. Sprinkling reduced RR and RT (P < 0.01) of all heifers during HOT1-3. During HOT4-5, WET heifers had lower (P < 0.05) RT than NONWET from 1300 to 700 h and lower RR from 1400 to 2000 h. Dry matter intake of NONWET heifers was reduced by 30.6% (P < 0.05) during HOT4-5 and by 51.2% on HOT6. On HOT4-5 the dry matter intakes of WET heifers were similar to intakes under thermoneutral conditions. During HOT6, RT was again reduced following sprinkling in all heifers. Comparison of RT and RR of NONWET and WET heifers on HOT1-3 v. HOT6 revealed that under similar environmental conditions, NONWET heifers had increased RT, partially due to carry-over from HOT4-5. However, NONWET heifers had 40% lower feed intake but tended to have lower RR on HOT6 v. HOT1-3. Only RR of WET heifers was greater on HOT6, possibly a result of switching from a 4-h back to a 2-h sprinkling period, while maintaining a 62% greater intake (5.80 v. 3.58 kg/day) than NONWET heifers during this time. Results suggest that inconsistent cooling regimens may increase the susceptibility of cattle to heat stress and elicit different physiological and metabolic responses.