RESUMO
We report on the electronic and magnetic properties of superconductor-ferromagnet heterostructures fabricated by electron beam evaporation on to unheated thermally oxidised Si substrates. Polycrystalline Nb thin films (5 to 50 nm thick) were shown to possess reliably high superconducting critical temperatures ([Formula: see text]), which correlate well with the residual resistivity ratio (RRR) of the film. These properties improved during ex-situ annealing, resulting in [Formula: see text] and [Formula: see text]RRR increases of up 2.2 K ([Formula: see text] 40% of the pre-annealed [Formula: see text]) and 0.8 ([Formula: see text] 60% of the pre-annealed RRR) respectively. Nb/Pt/Co/Pt heterostructures showed substantial perpendicular anisotropy in the ultrathin limit (≤ 2.5 nm), even in the extreme limit of Pt(0.8 nm)/Co(1 nm)/Pt(0.6 nm). These results point to the use of electron beam evaporation as route to line-of-sight deposited, low-thickness, high quality Nb-based superspintronic multilayers.
RESUMO
The Spontaneously Hypertensive Heart Failure (SHHF) rat mimics the human progression of hypertension from hypertrophy to heart failure. However, it is unknown whether SHHF animals can exercise at sufficient levels to observe beneficial biochemical adaptations in skeletal muscle. Thirty-seven female SHHF and Wistar-Furth (WF) rats were randomized to sedentary (SHHFsed and WFsed) and exercise groups (SHHFex and WFex). The exercise groups had access to running wheels from 6-22 months of age. Hindlimb muscles were obtained for metabolic measures that included mitochondrial enzyme function and expression, and glycogen utilization. The SHHFex rats ran a greater distance and duration as compared to the WFex rats (P<0.05), but the WFex rats ran at a faster speed (P<0.05). Skeletal muscle citrate synthase and beta-hydroxyacyl-CoA dehydrogenase enzyme activity was not altered in the SHHFex group, but was increased (P<0.05) in the WFex animals. Citrate synthase protein and gene expression were unchanged in SHHFex animals, but were increased in WFex rats (P<0.05). In the WFex animals muscle glycogen was significantly depleted after exercise (P<0.05), but not in the SHHFex group. We conclude that despite robust amounts of aerobic activity, voluntary wheel running exercise was not sufficiently intense to improve the oxidative capacity of skeletal muscle in adult SHHF animals, indicating an inability to compensate for declining heart function by improving peripheral oxidative adaptations in the skeletal muscle.
Assuntos
Metabolismo Energético , Insuficiência Cardíaca/etiologia , Hipertensão/complicações , Contração Muscular , Músculo Esquelético/metabolismo , Esforço Físico , 3-Hidroxiacil-CoA Desidrogenases/genética , 3-Hidroxiacil-CoA Desidrogenases/metabolismo , ATP Citrato (pro-S)-Liase/genética , ATP Citrato (pro-S)-Liase/metabolismo , Adaptação Fisiológica , Animais , Modelos Animais de Doenças , Feminino , Glicogênio/metabolismo , Glicólise , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Membro Posterior , Hipertensão/genética , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Músculo Esquelético/fisiopatologia , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WF , Corrida , Fatores de TempoRESUMO
Exaggerated male ornaments are predicted to be costly to their bearers, but these negative effects may be offset by the correlated evolution of compensatory traits. However, when locomotor systems, such as wings in flying species, evolve to decrease such costs, it remains unclear whether functional changes across related species are achieved via the same morphological route or via alternate changes that have similar function. We conducted a comparative analysis of wing shape in relation to eye-stalk elongation across 24 species of stalk-eyed flies, using geometric morphometrics to determine how species with increased eye span, a sexually selected trait, have modified wing morphology as a compensatory mechanism. Using traditional and phylogenetically informed multivariate analyses of shape in combination with phenotypic trajectory analysis, we found a strong phylogenetic signal in wing shape. However, dimorphic species possessed shifted wing veins with the result of lengthening and narrowing wings compared to monomorphic species. Dimorphic species also had changes that seem unrelated to wing size, but instead may govern wing flexion. Nevertheless, the lack of a uniform, compensatory pattern suggests that stalk-eyed flies used alternative modifications in wing structure to increase wing area and aspect ratio, thus taking divergent morphological routes to compensate for exaggerated eye stalks.
Assuntos
Evolução Biológica , Dípteros/anatomia & histologia , Filogenia , Asas de Animais/anatomia & histologia , Animais , Dípteros/classificação , MasculinoRESUMO
Selective-breeding of house mice for increased voluntary wheel-running has resulted in multiple physiological and behavioral changes. Characterizing these differences may lead to experimental models that can elucidate factors involved in human diseases and disorders associated with physical inactivity, or potentially treated by physical activity, such as diabetes, obesity, and depression. Herein, we present ethological data for adult males from a line of mice that has been selectively bred for high levels of voluntary wheel-running and from a non-selected control line, housed with or without wheels. Additionally, we present concentrations of central monoamines in limbic, striatal, and midbrain regions. We monitored wheel-running for 8 weeks, and observed home-cage behavior during the last 5 weeks of the study. Mice from the selected line accumulated more revolutions per day than controls due to increased speed and duration of running. Selected mice exhibited more active behaviors than controls, regardless of wheel access, and exhibited less inactivity and grooming than controls. Selective-breeding also influenced the longitudinal patterns of behavior. We found statistically significant differences in monoamine concentrations and associated metabolites in brain regions that influence exercise and motivational state. These results suggest underlying neurochemical differences between selected and control lines that may influence the observed differences in behavior. Our results bolster the argument that selected mice can provide a useful model of human psychological and physiological diseases and disorders.
Assuntos
Comportamento Animal/fisiologia , Monoaminas Biogênicas/metabolismo , Química Encefálica/genética , Química Encefálica/fisiologia , Corrida/fisiologia , Corrida/psicologia , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Análise de Variância , Animais , Peso Corporal , Cruzamento , Dopamina/metabolismo , Ácido Hidroxi-Indolacético/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Motivação , Atividade Motora/genética , Atividade Motora/fisiologia , Seleção Genética , Serotonina/metabolismoRESUMO
We investigated the effects of genetic selection and prolonged wheel access (8 wk) on food consumption and body composition in lines of rats selected for high and low intrinsic (untrained) endurance running capacity (HCR and LCR, respectively) to test the generality of phenotypic correlations between physical activity levels, aerobic capacity, and body composition. HCR rats ran more minutes per day on activity wheels than LCR rats, supporting the hypothesis that voluntary activity and physiological capacity are genetically correlated (self-induced adaptive plasticity). Both treatments (selection and wheel access) significantly affected food consumption. HCR rats consumed and digested more food than LCR rats. Access to running wheels did not result in changes in overall body mass, but lean body mass increased and percent body fat decreased in both lines. Selection for high endurance capacity resulted in hypertrophy of the heart and kidneys and decreased long intestine length. We found significant phenotypic flexibility in a number of organ masses after wheel running. Specifically, access to running wheels resulted in hypertrophy of the heart, liver, kidney, stomach, and small and large intestines in LCR and HCR rats. The selected line×wheel access interaction was significantly greater in HCR rats in relative mass for the heart and lung. Compared with LCR rats, HCR rats fortify wheel running with increased food consumption along with greater hypertrophy of key organs for O2 transport.
Assuntos
Comportamento Animal , Composição Corporal/genética , Atividade Motora/genética , Resistência Física/genética , Animais , Cardiomegalia/genética , Cardiomegalia/patologia , Ingestão de Alimentos/genética , Feminino , Genótipo , Hipertrofia , Intestinos/patologia , Análise dos Mínimos Quadrados , Fígado/patologia , Masculino , Fenótipo , Ratos , Ratos Endogâmicos , Seleção Genética , Estômago/patologia , Fatores de Tempo , VoliçãoRESUMO
A positive genetic relationship between aerobic capacity and voluntary exercise has been suggested from earlier studies of mice selected for increased wheel-running activity. To further investigate the relationship between aerobic capacity and exercise behavior, wheel-running activity was studied in female rats bidirectionally selected for intrinsic aerobic capacity (high capacity runners - HCR; low capacity runners - LCR). Aerobic capacity was measured using a forced treadmill paradigm; the subpopulations of animals used in this experiment exhibited a 471% difference in endurance capacity. Rats were housed individually, with or without access to running wheels. Wheel-running activity was recorded and analyzed from weeks two through seven during an eight-week trial to determine voluntary activity levels. HCR animals exhibited 33% greater total wheel-running distance per day compared to LCR rats (16,838.7+1337.30 m versus 12,665.8+893.88 m), which was due to the HCR rats exhibiting increases in both running speed and duration over LCR rats. Differences in the intermittency of wheel running were also observed. HCR rats engaged in more bouts of running per day than LCR rats, and trended towards running faster, for more time, and for longer distances during bouts of running than LCR rats. Following the running trial, measurement of plasma corticosterone concentration and striatal dopaminergic activity showed differences between HCR and LCR rats, suggesting a divergence of physiological systems that could potentially influence locomotor behaviors in these lines. These results are consistent with earlier work, and suggest an evolutionarily conserved relationship between physiological capacity and behavioral activity of exercise.
Assuntos
Monoaminas Biogênicas/metabolismo , Corticosterona/sangue , Movimento/fisiologia , Condicionamento Físico Animal/métodos , Seleção Genética , Análise de Variância , Animais , Comportamento Animal , Índice de Massa Corporal , RatosRESUMO
Evolutionary biologists have long been interested in the processes influencing population differentiation, but separating the effects of neutral and adaptive evolution has been an obstacle for studies of population subdivision. A recently developed method allows tests of whether disruptive (ie, spatially variable) or stabilizing (ie, spatially uniform) selection is influencing phenotypic differentiation among subpopulations. This method, referred to as the F(ST) vs Q(ST) comparison, separates the total additive genetic variance into within- and among-population components and evaluates this level of differentiation against a neutral hypothesis. Thus, levels of neutral molecular (F(ST)) and quantitative genetic (Q(ST)) divergence are compared to evaluate the effects of selection and genetic drift on phenotypic differentiation. Although the utility of such comparisons appears great, its accuracy has not yet been evaluated in populations with known evolutionary histories. In this study, F(ST) vs Q(ST) comparisons were evaluated using laboratory populations of house mice with known evolutionary histories. In this model system, the F(ST) vs Q(ST) comparisons between the selection groups should reveal quantitative trait differentiation consistent with disruptive selection, while the F(ST) vs Q(ST) comparisons among lines within the selection groups should suggest quantitative trait differentiation in agreement with drift. We find that F(ST) vs Q(ST) comparisons generally produce the correct evolutionary inference at each level in the population hierarchy. Additionally, we demonstrate that when strong selection is applied between populations Q(ST) increases relative to Q(ST) among populations diverging by drift. Finally, we show that the statistical properties of Q(ST), a variance component ratio, need further investigation.
Assuntos
Evolução Molecular , Variação Genética , Genética Populacional , Camundongos/genética , Característica Quantitativa Herdável , Animais , Feminino , Frequência do Gene , Deriva Genética , Marcadores Genéticos , Genótipo , Masculino , Modelos Genéticos , Fenótipo , Seleção GenéticaRESUMO
A complete understanding of the mode of evolution of molecular markers is important for making inferences about different population genetic parameters, especially because a number of studies have reported patterns of allelic variation at molecular markers that are not in agreement with neutral evolutionary expectations. In the present study, house mice (Mus domesticus) from the fourteenth generation of a selection experiment for increased voluntary wheel-running activity were used to test how selection on a complex behavior affects the distribution of allelic variation by examining patterns of variation at six microsatellite and four allozyme loci. This population had a hierarchical structure that allowed for simultaneous testing of the effects of selection and genetic drift on the distribution of allelic variation by comparing observed patterns of allele frequencies and estimates of genetic divergence at multiple hierarchical levels to expectations under models of neutral evolution. The levels of genetic divergence among replicate lines and between selection groups, estimated from microsatellite data or pooled microsatellite and allozyme data, were not significantly different from expectations under neutral evolution. Furthermore, the pattern of change of allele frequencies between the base population and generation 14 was largely in agreement with expectations under neutral evolution (although the PGM locus exhibited a pattern of change within populations that was difficult to explain under neutral evolution). Overall the results generally provide support for the neutral evolution of molecular markers.
Assuntos
Evolução Biológica , Marcadores Genéticos , Variação Genética , Atividade Motora/genética , Animais , Cruzamentos Genéticos , Feminino , Frequência do Gene , Genótipo , Isoenzimas/genética , Masculino , Camundongos , Camundongos Endogâmicos ICR , Repetições de MicrossatélitesRESUMO
Pain following tonsillectomy in children is a significant problem that tends to be underestimated. We audited post-operative pain in 33 children and found significant proportions of children in moderately severe to severe pain, particularly at, or soon after returning to the ward. These findings led to changes in practice that included the administration of pre-operative paracetamol and diclofenac as well as the uniform post-operative prescription of them, with printed instructions to reduce the scope for mistakes by medical staff. Other changes included a uniform policy, with which the nursing staff could become familiar, and the regular formal recording of pain to assist in the recognition of pain and analgesic requirements. On re-auditing two years later, in a group of 100 children, post-operative pain was significantly improved. The proportion experiencing moderately severe to severe pain on returning to the ward, as their maximum pain score and pain score at discharge fell from 70 per cent to 48 per cent, 85 per cent to 56 per cent, and six per cent to two per cent respectively.
Assuntos
Analgesia , Auditoria Médica , Dor Pós-Operatória/prevenção & controle , Tonsilectomia , Acetaminofen/uso terapêutico , Adolescente , Anti-Inflamatórios não Esteroides/administração & dosagem , Criança , Pré-Escolar , Codeína/uso terapêutico , Diclofenaco/uso terapêutico , Humanos , Medição da Dor , Pré-MedicaçãoRESUMO
To test the hypothesis that selective breeding for high voluntary wheel running negatively affects maternal performance in house mice, we observed maternal behavior and compared litter size and mass, in replicate lines of selected (N=4) and control (N=4) mice from generations 20 and 21 of an artificial selection experiment. At generation 21, selected-line females ran 2.8-times more revolutions per day than females from random-bred control lines, when tested at approximately 6 weeks of age as part of the normal selection protocol. After giving birth, dams from selected and control lines exhibited similar frequencies of maternal behaviors and also spent similar amounts of time in general locomotor activity at litter ages of both 9 and 16 days. Dams from selected lines also performed equally well as controls in repeated pup-retrieval trials. At first parturition, selected-line dams averaged 2.4 g smaller in body mass as compared with dams from the control lines; however, neither litter size nor litter mass at birth (generation 20) or at weaning (generation 21) differed significantly between selected and control lines. We conclude that, at least under the husbandry conditions employed, maternal behavior and reproductive output at first parturition are genetically independent of wheel-running behavior.
RESUMO
The objective of this study was to examine the correlated response of anti-oxidant enzyme activity to selective breeding for increased voluntary wheel running in house mice. Activity of liver superoxide dismutase-2 (Sod-2), a free radical scavenger, was measured in four groups of mice. 'Active' individuals were housed in cages with attached wheels for 8 weeks beginning at weaning; 'sedentary' individuals were housed in cages with attached wheels that were prevented from rotating. Both of these treatments were applied to male and female mice from generation 14 of a replicated artificial selection experiment, which is composed of four lines selected for high wheel running and four randomly bred lines that serve as controls. In females, Sod-2 activity was significantly lower in selected vs control animals, regardless of presence/absence of a free-turning wheel. This difference suggests a trade-off between early-age voluntary wheel-running activity and Sod-2 activity. In males, Sod-2 activity was significantly affected by an interaction between selection group and activity group, with males from selected lines having lower Sod-2 activity relative to control males only in the sedentary treatment. These negative correlated responses of Sod-2 activity to selection on wheel running are discussed in the context of antagonistic pleiotropy models of aging and with respect to potential effects on lifespan.
Assuntos
Esforço Físico , Seleção Genética , Superóxido Dismutase/metabolismo , Análise de Variância , Animais , Cruzamento , Feminino , Locomoção , Masculino , Camundongos , Estresse OxidativoRESUMO
Open-field behavioral assays are commonly used to test both locomotor activity and emotionality in rodents. We performed open-field tests on house mice (Mus domesticus) from four replicate lines genetically selected for high voluntary wheel-running for 22 generations and from four replicate random-bred control lines. Individual mice were recorded by video camera for 3 min in a 1-m2 open-field arena on 2 consecutive days. Mice from selected lines showed no statistical differences from control mice with respect to distance traveled, defecation, time spent in the interior, or average distance from the center of the arena during the trial. Thus, we found little evidence that open-field behavior, as traditionally defined, is genetically correlated with wheel-running behavior. This result is a useful converse test of classical studies that report no increased wheel-running in mice selected for increased open-field activity. However, mice from selected lines turned less in their travel paths than did control-line mice, and females from selected lines had slower travel times (longer latencies) to reach the wall. We discuss these results in the context of the historical open-field test and newly defined measures of open-field activity.
Assuntos
Nível de Alerta/genética , Comportamento Exploratório/fisiologia , Camundongos/genética , Atividade Motora/fisiologia , Seleção Genética , Animais , Feminino , Masculino , Tempo de Reação/genética , Fatores SexuaisRESUMO
Effects of genetic selection for high wheel-running activity (17th generation) and access to running wheels on skeletal muscle glucose uptake were studied in mice with the following treatments for 8 wk: 1) access to unlocked wheels; 2) same as 1, but wheels locked 48 h before glucose uptake measurement; or 3) wheels always locked. Selected mice ran more than random-bred (nonselected) mice (8-wk mean +/- SE = 8,243 +/- 711 vs. 3,719 +/- 233 revolutions/day). Body weight was 5-13% lower for selected vs. nonselected groups. Fat pad/body weight was ~40% lower for selected vs. nonselected and unlocked vs. locked groups. Insulin-stimulated glucose uptake and fat pad/body weight were inversely correlated for isolated soleus (r = -0.333; P < 0.005) but not extensor digitorum longus (EDL) or epitrochlearis muscles. Insulin-stimulated glucose uptake was higher in EDL (P < 0.02) for selected vs. nonselected mice. Glucose uptake did not differ by wheel group, and amount of running did not correlate with glucose uptake for any muscle. Wheel running by mice did not enhance subsequent glucose uptake by isolated muscles.
Assuntos
Glucose/farmacocinética , Camundongos Endogâmicos ICR/genética , Músculo Esquelético/metabolismo , Esforço Físico/fisiologia , Animais , Antimetabólitos/farmacocinética , Glicemia/metabolismo , Cruzamento , Desoxiglucose/farmacocinética , Feminino , Glicogênio/metabolismo , Hematócrito , Hipoglicemiantes/sangue , Hipoglicemiantes/farmacologia , Insulina/sangue , Insulina/farmacologia , Fígado/anatomia & histologia , Fígado/metabolismo , Masculino , Camundongos , Atividade Motora/fisiologia , Músculo Esquelético/anatomia & histologia , Tamanho do ÓrgãoRESUMO
The pain experienced at home and the burden this places on primary care resources is considerable following tonsillectomy in children. This was audited by postal questionnaire in 52 patients (36 responders). We found a significant proportion of patients experiencing moderately severe to severe pain and a high rate of consultation with general practitioners (50 per cent) for pain-related issues. These findings lead to changes in practice which included the provision of five days discharge medication (paracetamol/ibuprofen in non-asthmatics; paracetamol/dihydrocodeine in asthmatics) and improved written discharge advice. On re-auditing a year later in 100 patients (56 responders), we found reduced rates of consultation with general practitioners (27 per cent). However, the proportion of children experiencing moderately severe to severe pain was not reduced probably because most children were given the recommended analgesia during the first audit. We also found that paracetamol and ibuprofen was superior to paracetamol and dihydrocodeine for analgesia (p <0.05). Suggestions for further improvements are discussed.
Assuntos
Codeína/análogos & derivados , Auditoria Médica , Dor Pós-Operatória/tratamento farmacológico , Tonsilectomia/métodos , Acetaminofen/uso terapêutico , Adolescente , Analgésicos não Narcóticos/uso terapêutico , Analgésicos Opioides/uso terapêutico , Distribuição de Qui-Quadrado , Criança , Pré-Escolar , Codeína/uso terapêutico , Quimioterapia Combinada , Humanos , Ibuprofeno/uso terapêutico , Lactente , Medição da Dor , Folhetos , Educação de Pacientes como Assunto/métodos , Atenção Primária à Saúde/estatística & dados numéricos , Encaminhamento e ConsultaRESUMO
We studied house mice (Mus domesticus) that had been artificially selected for high activity to test the hypothesis that a high capacity for energy assimilation in cold-exposed endotherms could evolve as a correlated response to selection for increased locomotor activity. After 10 generations of selection for increased voluntary wheel-running, mice from four selected lines ran 75 % more wheel revolutions per day than did mice from four random-bred, control lines. The maximum cold-induced rates of food consumption (C(max); mean 10.6 g day(-1)) and energy assimilation (A(max); mean 141 kJ day(-1)) were not significantly higher in the selected than in the control mice. However, in cold-exposure trials, mice from the selected lines maintained body mass better than did mice from the control lines. C(max) and A(max) were positively correlated with the amount of wheel-running activity measured before cold-exposure and also with the rates of food consumption measured when the mice had access to running wheels. In females at least, the correlation was significant not only among individuals but also among adjusted means of the replicate lines, which suggests the presence of a positive genetic correlation between the traits. Thus, despite the lack of a significant difference between the selected and control lines in maximum rate of food consumption, the remaining results conform to the hypothesis that a selection for increased locomotor activity could be a factor behind the evolution of the ability to sustain activity and maintain energy balance during prolonged cold-exposure, as occurred during the evolution of mammalian and avian endothermy.
Assuntos
Evolução Biológica , Temperatura Baixa , Ingestão de Alimentos , Metabolismo Energético , Camundongos/fisiologia , Atividade Motora/fisiologia , Animais , TermogêneseRESUMO
The effects of genetic selection for high wheel running (13th generation) and prolonged access (8 weeks) to running wheels on food consumption and body composition were studied in house mice (Mus domesticus). Mice from four replicate lines selected for high wheel-running activity ran over twice as many revolutions per day on activity wheels as did mice from four replicate control lines. At approximately 49 days of age, all mice were placed individually in cages with access to wheels and monitored for 6 days, after which wheels were prevented from rotating for the "sedentary" individuals. During the experiment, five feeding trials were conducted and body mass was measured weekly. After 8 weeks, body composition was measured by hydrogen isotope dilution. Across the five feeding trials, mice in the "active" group (wheels free to rotate) consumed 22.4% more food than mice in the "sedentary" group (wheels locked); mice from the selected lines consumed 8.4% more food than mice from the control lines (average of all trials; body mass-corrected values). In females, but not males, we found a significant interaction between selection and wheel access treatments: within the "active" group the difference in food consumption between selected and control animals was greater than in the "sedentary" group. At the end of the study, mice from the "active" and "sedentary" groups did not differ significantly in body mass; however, mice from the selected lines were approximately 6% smaller in body mass. Estimated lean body mass did not differ significantly either between selected and control lines or between wheel-access groups (P>0.3). Mice from selected lines had lower total body fat compared to mice from control lines (P=0.05; 24.5% reduction; LSMEANS) as did mice from the "active" compared to "sedentary" group (P= 0.03; 29.2% reduction; LSMEANS). Under these conditions, a sufficient explanation for the difference in body mass between the selected and control lines was the difference in fat content.
Assuntos
Composição Corporal/fisiologia , Ingestão de Alimentos/fisiologia , Atividade Motora/fisiologia , Animais , Peso Corporal , Feminino , Masculino , Camundongos , Camundongos Endogâmicos ICR , Caracteres SexuaisRESUMO
Stalk-eyed flies have eyes placed laterally away from the head on elongated peduncles. The elongation of eye span may increase the energetic cost of flight, reduce flight performance via aerodynamic effects or via increased load, or necessitate compensatory changes in other body dimensions. Body mass and body dimensions were measured to test the hypothesis that elongation of eye span is correlated with increased head mass in two closely related species of stalk-eyed flies. Cyrtodiopsis whitei is sexually dimorphic, with the eye span of larger males exceeding body length. Cyrtodiopsis quinqueguttata is sexually monomorphic with eye span substantially less than body length. Although eye span was significantly longer in C. whitei, head mass did not differ between species after accounting for differences in body mass. C. whitei males had longer wings, heavier thoraxes, and lighter abdomens in relation to body mass than did female C. whitei or C. quinqueguttata of either sex. Three-dimensional tracking of flight paths showed that path velocity and the horizontal component of velocity did not differ according to species or sex, but the long-eyed C. whitei males showed reduced overall aerial performance by flying at shallower ascent angles and reduced vertical velocity. Although increased mass loading does not occur in C. whitei males, increased drag, aerodynamic effects from the wake of the eye stalks, and constrained visual processing are possible mechanisms which could cause their reduced performance.
Assuntos
Dípteros/fisiologia , Voo Animal/fisiologia , Fenômenos Fisiológicos Oculares , Animais , Dípteros/anatomia & histologia , Feminino , Masculino , Caracteres SexuaisRESUMO
Selective breeding is an important tool in behavioral genetics and evolutionary physiology, but it has rarely been applied to the study of exercise physiology. We are using artificial selection for increased wheel-running behavior to study the correlated evolution of locomotor activity and physiological determinants of exercise capacity in house mice. We studied enzyme activities and their response to voluntary wheel running in mixed hindlimb muscles of mice from generation 14, at which time individuals from selected lines ran more than twice as many revolutions per day as those from control (unselected) lines. Beginning at weaning and for 8 wk, we housed mice from each of four replicate selected lines and four replicate control lines with access to wheels that were free to rotate (wheel-access group) or locked (sedentary group). Among sedentary animals, mice from selected lines did not exhibit a general increase in aerobic capacities: no mitochondrial [except pyruvate dehydrogenase (PDH)] or glycolytic enzyme activity was significantly (P < 0.05) higher than in control mice. Sedentary mice from the selected lines exhibited a trend for higher muscle aerobic capacities, as indicated by higher levels of mitochondrial (cytochrome-c oxidase, carnitine palmitoyltransferase, citrate synthase, and PDH) and glycolytic (hexokinase and phosphofructokinase) enzymes, with concomitant lower anaerobic capacities, as indicated by lactate dehydrogenase (especially in male mice). Consistent with previous studies of endurance training in rats via voluntary wheel running or forced treadmill exercise, cytochrome-c oxidase, citrate synthase, and carnitine palmitoyltransferase activity increased in the wheel-access groups for both genders; hexokinase also increased in both genders. Some enzymes showed gender-specific responses: PDH and lactate dehydrogenase increased in wheel-access male but not female mice, and glycogen phosphorylase decreased in female but not in male mice. Two-way analysis of covariance revealed significant interactions between line type and activity group; for several enzymes, activities showed greater changes in mice from selected lines, presumably because such mice ran more revolutions per day and at greater velocities. Thus genetic selection for increased voluntary wheel running did not reduce the capability of muscle aerobic capacity to respond to training.
Assuntos
Mitocôndrias Musculares/enzimologia , Atividade Motora/fisiologia , Músculo Esquelético/fisiologia , Seleção Genética , Animais , Carnitina O-Palmitoiltransferase/metabolismo , Citrato (si)-Sintase/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Feminino , Glicólise , Heterozigoto , Hexoquinase/metabolismo , L-Lactato Desidrogenase/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Fosfofrutoquinase-1/metabolismo , Complexo Piruvato Desidrogenase/metabolismo , CorridaRESUMO
Nest building was measured in "active" (housed with access to running wheels) and "sedentary" (without wheel access) mice (Mus domesticus) from four replicate lines selected for 10 generations for high voluntary wheel-running behavior, and from four randombred control lines. Based on previous studies of mice bidirectionally selected for thermoregulatory nest building, it was hypothesized that nest building would show a negative correlated response to selection on wheel-running. Such a response could constrain the evolution of high voluntary activity because nesting has also been shown to be positively genetically correlated with successful production of weaned pups. With wheel access, selected mice of both sexes built significantly smaller nests than did control mice. Without wheel access, selected females also built significantly smaller nests than did control females, but only when body mass was excluded from the statistical model, suggesting that body mass mediated this correlated response to selection. Total distance run and mean running speed on wheels was significantly higher in selected mice than in controls, but no differences in amount of time spent running were measured, indicating a complex cause of the response of nesting to selection for voluntary wheel running.
Assuntos
Genótipo , Camundongos/genética , Atividade Motora/genética , Comportamento de Nidação , Seleção Genética , Animais , Peso Corporal/genética , Feminino , MasculinoRESUMO
The ultimate safety of drinking water depends upon protection of source waters and construction and maintenance of reliable drinking water treatment and distribution systems. These objectives require public support. Physicians can encourage their patients to call their water suppliers and advocate for investment in effective treatment systems and support zoning that will protect water supply watersheds and wellheads. The Consumer Confidence Reports are meant to inform consumers about their drinking water supply. Consumers should use the reports to verify that their drinking water meets all health standards and to understand some of the potential threats to their drinking water quality. Physicians may use the reports as an opportunity to discuss the many types of environmental exposures and ways to reduce these exposures. As a crucial component of the public health community, this is your opportunity to encourage your patients to become more aware of their environment and its impact on their health.