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1.
Chem Commun (Camb) ; 2024 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-39248075

RESUMEN

X-ray photoelectron spectroscopy (XPS) and ab initio calculations show that fully alkylated onium cation electronic structure can be tuned using both the alkyl chains and the central onium atom. The key for tuning the central onium atom is methyl versus longer alkyl chains, allowing selection of the optimum cation for a wide range of applications, including catalysis and biocides.

2.
J Exp Biol ; 2024 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-39206634

RESUMEN

It is widely accepted that birds can adaptively regulate body mass in different ecological contexts, but little is known about how birds monitor and interpret their body mass or the mechanisms that allow for rapid changes in mass. Using captive zebra finches (Taeniopygia guttata), we experimentally increased perceived mass via attachment of weighted backpacks and provided birds with either an ad libitum mixed-seed diet or supplementary high-fat diet to investigate (a) how birds assess their own body mass and (b) the physiological and/or behavioral mechanisms birds may employ to rapidly adjust body mass. In both experiments, and independent of diet treatment, birds with weighted backpacks rapidly lost mass within two days of backpack attachment while reducing overall activity and maintaining food intake. Additionally, our data suggest that birds interpret body mass via a physical mechanosensory pathway rather than a physiological pathway: rapid loss of mass between days 0 and 2 was not linked to changes in plasma metabolites (glycerol or triglyceride concentrations). We found no evidence that mass loss was a consequence of stress associated with attachment of weighted backpacks (based on plasma corticosterone measures). Our results suggest that the processes of energy balance and mass regulation involve a greater array of mechanisms than simply matching energy in through the amount of food consumed to energy out, dictated by activity: zebra finches were able to decrease body mass through other, unidentified, mechanisms even while maintaining dietary intake and reducing overall activity.

3.
J Equine Vet Sci ; 141: 105167, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39151810

RESUMEN

Historically, 8 × 0.5 ml straws, containing approximately 800 million sperm and 250 million progressively motile sperm were provided as a single 'breeding dose' of cryopreserved stallion semen. With the use of deep horn artificial insemination, there is a trend to reduce the number of 0.5 ml straws sold as a breeding dose, sometimes down to as little as one straw. Our aims were to determine if the number of straws provided as a breeding dose, as well as other mare, stallion and management factors, have an impact on pregnancy outcome in mares inseminated with cryopreserved semen. Unexpectedly, we identified no effect of the number of 0.5 ml straws on pregnancy outcome. We also identified no difference in pregnancy outcome for those mares inseminated once post-ovulation compared to mares inseminated once pre- and once post- ovulation. Additionally, for mares inseminated once post-ovulation, we identified no benefit of breeding 0-3 hours post-ovulation vs. breeding 0-6 hours post-ovulation. Other factors not associated with pregnancy outcome included: whether an endometrial sample was obtained for bacteriologic culture, whether the endometrial sample produced bacterial growth, whether a mare developed fluid after breeding, whether a mare was treated for bacterial endometritis and/or uterine fluid, and post-thaw progressive sperm motility. These results suggest the existence of an effective industry self-selection process in which only semen from the most fertile stallions is marketed in these 'ultra-low' doses and that breeding mares within 3 hours post- ovulation provides no benefit to pregnancy outcome compared to breeding mares within 6 hours post-ovulation.


Asunto(s)
Criopreservación , Inseminación Artificial , Preservación de Semen , Caballos , Femenino , Animales , Embarazo , Preservación de Semen/veterinaria , Preservación de Semen/métodos , Inseminación Artificial/veterinaria , Índice de Embarazo , Masculino , Semen
4.
J Virol ; 98(9): e0099324, 2024 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-39162432

RESUMEN

The cucumber mosaic virus (CMV) 2b protein is a potent counter-defense factor and symptom determinant that inhibits antiviral silencing by titrating short double-stranded RNAs. Expression of the CMV subgroup IA strain Fny-CMV 2b protein in transgenic Arabidopsis thaliana plants disrupts microRNA-mediated cleavage of host mRNAs by binding Argonaute 1 (AGO1), leading to symptom-like phenotypes. This also triggers AGO2-mediated antiviral resistance and resistance to CMV's aphid vectors. However, in authentic viral infections, the Fny-CMV 1a protein modulates 2b-AGO1 interactions, inhibiting induction of AGO2-mediated virus resistance and aphid resistance. Contrastingly, 2b proteins encoded by the subgroup II strain LS-CMV and the recently discovered subgroup IA strain Ho-CMV induce no symptoms. Confocal laser scanning microscopy, bimolecular fluorescence complementation, and co-immunoprecipitation showed that Fny-CMV and Ho-CMV 2b proteins interact with Fny-CMV and LS-CMV 1a proteins, while the CMV-LS 2b protein cannot. However, Fny-CMV, Ho-CMV, and LS-CMV 2b proteins, all interacted with AGO1, but while AGO1-Fny2b complexes occurred in the nucleus and cytoplasm, corresponding AGO1-2b complexes for LS-CMV and Ho-CMV accumulated almost exclusively in nuclei. AGO2 transcript accumulation was used to assess the inhibition of AGO1-mediated mRNA degradation. Fny-CMV 2b induced a fivefold increase in AGO2 accumulation, but LS-CMV and Ho-CMV 2b proteins induced only twofold increases. Thus, these 2b proteins bind AGO1 but are less effective at inhibiting AGO1 activity. We conclude that the intracellular localization of 2b-AGO1 complexes influences the degree to which a 2b protein inhibits microRNA-mediated host mRNA degradation and that cytoplasmic AGO1 has the strongest influence on miRNA-mediated cellular mRNA turnover. IMPORTANCE: The cucumber mosaic virus (CMV) 2b protein was among the first discovered viral suppressors of RNA silencing. It has additional pro-viral functions through effects on plant defensive signaling pathways mediated by salicylic acid and jasmonic acid, the abscisic acid pathway and virus-induced drought resistance, and on host plant interactions with insect vectors. Many of these effects occur due to interaction with the important host RNA silencing component Argonaute 1 (AGO1). It was thought that only 2b proteins of "severe" CMV strains interacted with AGO1 and inhibited its microRNA-mediated "slicing" of cellular mRNAs and that the lack of interaction with AGO1 explained the moderate symptoms typically seen in plants infected with mild CMV strains. Our work overthrows this paradigm by showing that mild strain CMV 2b proteins can interact with AGO1, but their in vivo localization prevents them from interacting with AGO1 molecules present in the infected cell cytoplasm.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Proteínas Argonautas , Cucumovirus , Proteínas Virales , Proteínas Argonautas/metabolismo , Proteínas Argonautas/genética , Cucumovirus/metabolismo , Arabidopsis/virología , Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas Virales/metabolismo , Proteínas Virales/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Enfermedades de las Plantas/virología , Interacciones Huésped-Patógeno , Plantas Modificadas Genéticamente , MicroARNs/metabolismo , MicroARNs/genética , Metiltransferasas
5.
Transl Psychiatry ; 14(1): 273, 2024 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-38961071

RESUMEN

Depression is the leading cause of disability worldwide, exerting a profound negative impact on quality of life in those who experience it. Depression is associated with disruptions to several closely related neural and cognitive processes, including dopamine transmission, fronto-striatal brain activity and connectivity, reward processing and motivation. Physical activity, especially aerobic exercise, reduces depressive symptoms, but the mechanisms driving its antidepressant effects are poorly understood. Here we propose a novel hypothesis for understanding the antidepressant effects of exercise, centred on motivation, across different levels of explanation. There is robust evidence that aerobic exercise decreases systemic inflammation. Inflammation is known to reduce dopamine transmission, which in turn is strongly implicated in effort-based decision making for reward. Drawing on a broad range of research in humans and animals, we propose that by reducing inflammation and boosting dopamine transmission, with consequent effects on effort-based decision making for reward, exercise initially specifically improves 'interest-activity' symptoms of depression-namely anhedonia, fatigue and subjective cognitive impairment - by increasing propensity to exert effort. Extending this framework to the topic of cognitive control, we explain how cognitive impairment in depression may also be conceptualised through an effort-based decision-making framework, which may help to explain the impact of exercise on cognitive impairment. Understanding the mechanisms underlying the antidepressant effects of exercise could inform the development of novel intervention strategies, in particular personalised interventions and boost social prescribing.


Asunto(s)
Ejercicio Físico , Motivación , Humanos , Motivación/fisiología , Recompensa , Dopamina/metabolismo , Dopamina/fisiología , Toma de Decisiones/fisiología , Depresión/terapia , Depresión/fisiopatología , Animales , Disfunción Cognitiva/fisiopatología , Disfunción Cognitiva/terapia , Terapia por Ejercicio/métodos , Inflamación , Trastorno Depresivo/terapia , Trastorno Depresivo/fisiopatología
6.
J Dairy Sci ; 107(9): 6658-6670, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38825143

RESUMEN

The present work aims to evaluate the dissociation of casein micelles in diluted skim milk (SM) systems after undergoing solvent- or emulsifying salt-based dissociation coupled with ultra-high-pressure homogenization (UHPH). Specifically, part I evaluated dilute SM solutions combined with varying ethanol concentrations (0%-60%) at varying temperatures (5-65°C) in combination with UHPH (100-300 MPa), and part II evaluated dilute SM solutions combined with varying concentrations (0-100 mM) of either sodium hexametaphosphate (SHMP) or sodium citrate (SC) in combination with UHPH (100-300 MPa). In part I, high concentrations of ethanol (40%-60% vol/vol) at elevated temperatures (45-65°C) achieved extensive dissociation of casein micelles, especially in combination with UHPH at ≥200 MPa, as shown by a reduction in sample absorbance and in casein particle size compared with the control (dilute SM, 65°C) under optimum conditions (dilute SM, 60% ethanol, 65°C, ≥200 MPa). In part II, the level of casein micelle dissociation using emulsifying salts (ES) was dependent on the ES type and concentration. Considerable casein micelle dissociation in dilute SM systems was achieved with SHMP concentrations ≥1 mM and SC concentrations ≥10 mM, resulting in decreased sample absorbance, bimodal casein size distributions, and increased hydrophobicity (∼2-fold increase in intrinsic fluorescence) compared with the control (dilute SM). This dissociation was further enhanced with UHPH (≥200 MPa). These results indicate that both solvent- and ES-based casein dissociation techniques can be optimized when used in combination with UHPH. Together, these processing techniques can be used to extensively dissociate casein micelles with the potential to use these altered systems for value-added applications such as functional ingredients or encapsulation agents.


Asunto(s)
Caseínas , Micelas , Leche , Caseínas/química , Leche/química , Animales , Tamaño de la Partícula , Interacciones Hidrofóbicas e Hidrofílicas
7.
Mol Ecol ; 33(12): e17365, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38733214

RESUMEN

When populations colonise new environments, they may be exposed to novel selection pressures but also suffer from extensive genetic drift due to founder effects, small population sizes and limited interpopulation gene flow. Genomic approaches enable us to study how these factors drive divergence, and disentangle neutral effects from differentiation at specific loci due to selection. Here, we investigate patterns of genetic diversity and divergence using whole-genome resequencing (>22× coverage) in Berthelot's pipit (Anthus berthelotii), a passerine endemic to the islands of three north Atlantic archipelagos. Strong environmental gradients, including in pathogen pressure, across populations in the species range, make it an excellent system in which to explore traits important in adaptation and/or incipient speciation. First, we quantify how genomic divergence accumulates across the speciation continuum, that is, among Berthelot's pipit populations, between sub species across archipelagos, and between Berthelot's pipit and its mainland ancestor, the tawny pipit (Anthus campestris). Across these colonisation timeframes (2.1 million-ca. 8000 years ago), we identify highly differentiated loci within genomic islands of divergence and conclude that the observed distributions align with expectations for non-neutral divergence. Characteristic signatures of selection are identified in loci associated with craniofacial/bone and eye development, metabolism and immune response between population comparisons. Interestingly, we find limited evidence for repeated divergence of the same loci across the colonisation range but do identify different loci putatively associated with the same biological traits in different populations, likely due to parallel adaptation. Incipient speciation across these island populations, in which founder effects and selective pressures are strong, may therefore be repeatedly associated with morphology, metabolism and immune defence.


Asunto(s)
Flujo Génico , Variación Genética , Genética de Población , Passeriformes , Selección Genética , Animales , Passeriformes/genética , Islas , Flujo Genético , Especiación Genética , Adaptación Fisiológica/genética , Genómica
8.
Ecol Evol ; 14(5): e11343, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38746548

RESUMEN

Urbanization modifies ecosystem conditions and evolutionary processes. This includes air pollution, mostly as tropospheric ozone (O3), which contributes to the decline of urban and peri-urban forests. A notable case are fir (Abies religiosa) forests in the peripheral mountains southwest of Mexico City, which have been severely affected by O3 pollution since the 1970s. Interestingly, some young individuals exhibiting minimal O3-related damage have been observed within a zone of significant O3 exposure. Using this setting as a natural experiment, we compared asymptomatic and symptomatic individuals of similar age (≤15 years old; n = 10) using histologic, metabolomic, and transcriptomic approaches. Plants were sampled during days of high (170 ppb) and moderate (87 ppb) O3 concentration. Given that there have been reforestation efforts in the region, with plants from different source populations, we first confirmed that all analyzed individuals clustered within the local genetic group when compared to a species-wide panel (Admixture analysis with ~1.5K SNPs). We observed thicker epidermis and more collapsed cells in the palisade parenchyma of needles from symptomatic individuals than from their asymptomatic counterparts, with differences increasing with needle age. Furthermore, symptomatic individuals exhibited lower concentrations of various terpenes (ß-pinene, ß-caryophylene oxide, α-caryophylene, and ß-α-cubebene) than asymptomatic trees, as evidenced through GC-MS. Finally, transcriptomic analyses revealed differential expression for 13 genes related to carbohydrate metabolism, plant defense, and gene regulation. Our results indicate a rapid and contrasting phenotypic response among trees, likely influenced by standing genetic variation and/or plastic mechanisms. They open the door to future evolutionary studies for understanding how O3 tolerance develops in urban environments, and how this knowledge could contribute to forest restoration.


La urbanización altera tanto las condiciones del ecosistema como los procesos evolutivos, siendo la contaminación del aire, principalmente el ozono troposférico (O3), un factor que contribuye al declive de los bosques urbanos y periurbanos. Un ejemplo destacado son los bosques de oyamel (Abies religiosa) en las montañas periféricas al suroeste de la Ciudad de México, que han sufrido graves afectaciones por la contaminación de O3 desde la década de 1970. Resulta curioso observar que algunos individuos jóvenes presentan un daño mínimo relacionado con el O3 dentro de zonas con una exposición significativa a este contaminante. Aprovechando este entorno como un experimento natural, hemos comparado individuos asintomáticos y sintomáticos de edad similar (≤15 años; n = 10) mediante enfoques histológicos, metabolómicos y transcriptómicos. Las muestras de plantas se recolectaron durante días con concentraciones altas (170 ppb) y moderadas (87 ppb) de O3. Dado que se han llevado a cabo esfuerzos de reforestación en la región con plantas de diferentes poblaciones, primero confirmamos que todos los individuos analizados se organizaron dentro del grupo genético local en comparación con un amplio panel poblacional de esta misma especie (Análisis de Admixture con ~1.5 K SNPs). Observamos una epidermis más gruesa y más células colapsadas en el parénquima en empalizada de las agujas de los individuos sintomáticos que de sus contrapartes asintomáticas, y estas diferencias aumentaban con la edad de la aguja. Además, los individuos sintomáticos exhibieron concentraciones más bajas de varios terpenos (ß­pineno, óxido de ß­cariofileno, α­cariofileno y ß­α­cubebeno) que los árboles asintomáticos, según se evidenció mediante GC­MS. Por último, los análisis transcriptómicos revelaron una expresión diferencial para trece genes relacionados con el metabolismo de carbohidratos, la defensa de plantas y la regulación génica. Nuestros resultados indican una respuesta fenotípica rápida y contrastante entre los árboles, probablemente influenciada por la variación genética presente y/o mecanismos plásticos. Estos hallazgos abren la puerta a futuros estudios evolutivos para comprender cómo se desarrolla la tolerancia al O3 en entornos urbanos y cómo este conocimiento podría contribuir a la restauración forestal.

9.
Mol Ecol Resour ; 24(5): e13969, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38747336

RESUMEN

A major aim of evolutionary biology is to understand why patterns of genomic diversity vary within taxa and space. Large-scale genomic studies of widespread species are useful for studying how environment and demography shape patterns of genomic divergence. Here, we describe one of the most geographically comprehensive surveys of genomic variation in a wild vertebrate to date; the great tit (Parus major) HapMap project. We screened ca 500,000 SNP markers across 647 individuals from 29 populations, spanning ~30 degrees of latitude and 40 degrees of longitude - almost the entire geographical range of the European subspecies. Genome-wide variation was consistent with a recent colonisation across Europe from a South-East European refugium, with bottlenecks and reduced genetic diversity in island populations. Differentiation across the genome was highly heterogeneous, with clear 'islands of differentiation', even among populations with very low levels of genome-wide differentiation. Low local recombination rates were a strong predictor of high local genomic differentiation (FST), especially in island and peripheral mainland populations, suggesting that the interplay between genetic drift and recombination causes highly heterogeneous differentiation landscapes. We also detected genomic outlier regions that were confined to one or more peripheral great tit populations, probably as a result of recent directional selection at the species' range edges. Haplotype-based measures of selection were related to recombination rate, albeit less strongly, and highlighted population-specific sweeps that likely resulted from positive selection. Our study highlights how comprehensive screens of genomic variation in wild organisms can provide unique insights into spatio-temporal evolutionary dynamics.


Asunto(s)
Variación Genética , Polimorfismo de Nucleótido Simple , Pájaros Cantores , Animales , Pájaros Cantores/genética , Pájaros Cantores/clasificación , Genética de Población/métodos , Europa (Continente) , Passeriformes/genética , Passeriformes/clasificación , Haplotipos/genética , Recombinación Genética , Selección Genética
10.
Ecol Evol ; 14(5): e11313, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38694756

RESUMEN

Small, isolated populations are often characterised by low levels of genetic diversity. This can result in inbreeding depression and reduced capacity to adapt to changes in the environment, and therefore higher risk of extinction. However, sometimes these populations can be rescued if allowed to increase in size or if migrants enter, bringing in new allelic variation and thus increasing genetic diversity. This study uses experimental manipulation of population size and migration to quantify their effects on fitness in a challenging environment to better understand genetic rescue. Using small, replicated populations of Tribolium castaneum experimentally evolved to different temperature regimes we tested genetic and demographic rescue, by performing large-scale manipulations of population size and migration and examining fitness consequences over multiple generations. We measured fitness in high temperature (38°C) thermal lines maintained at their usual 'small' population size of N = 100 individuals, and with 'large' scaled up duplicates containing N≈10,000 individuals. We compared these large lines with and without migration (m = 0.1) for 10 generations. Additionally, we assessed the effects of outcrossing at an individual level, by comparing fitness of hybrid (thermal line × stock) offspring with within-line crosses. We found that, at the population level, a rapid increase in the number of individuals in the population resulted in reduced fitness (represented by reproductive output and survival through heatwave conditions), regardless of migration. However, at an individual level, the hybrid offspring of migrants with native individuals generally demonstrated increased longevity in high temperature conditions compared with individuals from thermal selection lines. Overall, these populations showed no evidence that demographic manipulations led to genetic or evolutionary rescue. Following the effects of migration in individuals over several generations may be the next step in unravelling these conflicting results. We discuss these findings in the context of conservation intervention.

11.
J Phys Chem B ; 128(20): 5030-5043, 2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-38727250

RESUMEN

Using a combination of experiments and calculations, we have gained new insights into the nature of anion-cation interactions in ionic liquids (ILs). An X-ray photoelectron spectroscopy (XPS)-derived anion-dependent electrostatic interaction strength scale, determined using XPS core-level binding energies for IL cations, is presented here for 39 different anions, with at least 18 new anions included. Linear correlations of experimental XPS core-level binding energies for IL cations with (a) calculated core binding energies (ab initio molecular dynamics (AIMD) simulations were used to generate high-quality model IL structures followed by single-point density functional theory (DFT) to obtain calculated core binding energies), (b) experimental XPS core-level binding energies for IL anions, and (c) other anion-dependent interaction strength scales led to three main conclusions. First, the effect of different anions on the cation can be related to ground-state interactions. Second, the variations of anion-dependent interactions with the identity of the anion are best rationalized in terms of electrostatic interactions and not occupied valence state/unoccupied valence state interactions or polarizability-driven interactions. Therefore, the XPS-derived anion-dependent interaction strength scale can be explained using a simple electrostatic model based on electrostatic site potentials. Third, anion-probe interactions, irrespective of the identity of the probe, are primarily electrostatic, meaning that our electrostatic interaction strength scale captures some inherent, intrinsic property of anions independent of the probe used to measure the interaction strength scale.

12.
J Evol Biol ; 37(7): 748-757, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38654518

RESUMEN

Dispersal is an important facet of the life history of many organisms and is, therefore, subject to selective pressure but does not evolve in isolation. Across nature, there are examples of dispersal syndromes and life history strategies in which suites of traits coevolve and covary with dispersal in combinations that serve to maximize fitness in a given ecological context. The red rust flour beetle, Tribolium castaneum, is a model organism and globally significant post-harvest pest that relies on dispersal to reach new patches of ephemeral habitat. Dispersal behaviour in Tribolium has a strong genetic basis. However, a robust understanding of the relationship between dispersal and other life-history components, which could elucidate evolutionary processes and allow pest managers to control their spread and reduce the impact of infestation, is currently lacking. Here, we use highly replicated lines of T. castaneum previously artificially selected for divergent small-scale dispersal propensity to robustly test several important life history components: reproductive strategy, development time, and longevity. As predicted, we find that a suite of important changes as a result of our selection on dispersal: high dispersal propensity is associated with a lower number of longer mating attempts by males, lower investment in early life reproduction by females, slower development of later-laid offspring, and longer female life span. These findings indicate that correlated intraspecific variation in dispersal and related traits may represent alternative life history strategies in T. castaneum. We therefore suggest that pest management efforts to mitigate the species' agro-economic impact should consider the eco-evolutionary dynamics within multiple life histories. The benefits of doing so could be felt both through improved targeting of efforts to reduce spread and also in forecasting how the selection pressures applied through pest management are likely to affect pest evolution.


Asunto(s)
Distribución Animal , Tribolium , Animales , Tribolium/genética , Tribolium/fisiología , Masculino , Femenino , Selección Genética , Rasgos de la Historia de Vida , Longevidad , Reproducción , Evolución Biológica
13.
iScience ; 27(5): 109581, 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38638576

RESUMEN

How individuals balance costs and benefits of group living remains central to understanding sociality. In relation to diet, social foraging provides many advantages but also increases competition. Nevertheless, social individuals may offset increased competition by broadening their diet and consuming novel foods. Despite the expected relationships between social behavior and dietary decisions, how sociality shapes individuals' novel food consumption remains largely untested in natural populations. Here, we use wild great tits to experimentally test how sociality predicts dietary decisions. We show that individuals with more social connections have higher propensity to use novel foods compared to socially peripheral individuals, and this is unrelated to neophobia, observations, and demographic factors. These findings indicate sociable individuals may offset potential costs of competition by foraging more broadly. We discuss how social environments may drive behavioral change in natural populations, and the implications for the causes and consequences of social strategies and dietary decisions.

14.
Sci Rep ; 14(1): 7298, 2024 03 27.
Artículo en Inglés | MEDLINE | ID: mdl-38538653

RESUMEN

A paradox of avian long-distance migrations is that birds must greatly increase their body mass prior to departure, yet this is presumed to substantially increase their energy cost of flight. However, here we show that when homing pigeons flying in a flock are loaded with ventrally located weight, both their heart rate and estimated energy expenditure rise by a remarkably small amount. The net effect is that costs per unit time increase only slightly and per unit mass they decrease. We suggest that this is because these homing flights are relatively fast, and consequently flight costs associated with increases in body parasite drag dominate over those of weight support, leading to an improvement in mass-specific flight economy. We propose that the relatively small absolute aerodynamic penalty for carrying enlarged fuel stores and flight muscles during fast flight has helped to select for the evolution of long-distance migration.


Asunto(s)
Columbidae , Vuelo Animal , Animales , Vuelo Animal/fisiología , Columbidae/fisiología , Metabolismo Energético/fisiología , Músculos
15.
Sci Adv ; 10(10): eadj3823, 2024 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-38446876

RESUMEN

Mutations that perturb leptin-melanocortin signaling are known to cause hyperphagia and obesity, but energy expenditure has not been well studied outside rodents. We report on a common canine mutation in pro-opiomelanocortin (POMC), which prevents production of ß-melanocyte-stimulating hormone (ß-MSH) and ß-endorphin but not α-MSH; humans, similar to dogs, produce α-MSH and ß-MSH from the POMC propeptide, but rodents produce only α-MSH. We show that energy expenditure is markedly lower in affected dogs, which also have increased motivational salience in response to a food cue, indicating increased wanting or hunger. There was no difference in satiety at a modified ad libitum meal or in their hedonic response to food, nor disruption of adrenocorticotropic hormone (ACTH) or thyroid axes. In vitro, we show that ß-MSH signals comparably to α-MSH at melanocortin receptors. These data implicate ß-MSH and ß-endorphin as important in determining hunger and moderating energy expenditure and suggest that this role is independent of the presence of α-MSH.


Asunto(s)
betaendorfina , beta-MSH , Humanos , Perros , Animales , betaendorfina/genética , Metabolismo Basal , Proopiomelanocortina/genética , Hambre , alfa-MSH/genética
16.
Mol Ecol ; 33(8): e17329, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38533805

RESUMEN

Patterns of pathogen prevalence are, at least partially, the result of coevolutionary host-pathogen interactions. Thus, exploring the distribution of host genetic variation in relation to infection by a pathogen within and across populations can provide important insights into mechanisms of host defence and adaptation. Here, we use a landscape genomics approach (Bayenv) in conjunction with genome-wide data (ddRADseq) to test for associations between avian malaria (Plasmodium) prevalence and host genetic variation across 13 populations of the island endemic Berthelot's pipit (Anthus berthelotii). Considerable and consistent spatial heterogeneity in malaria prevalence was observed among populations over a period of 15 years. The prevalence of malaria infection was also strongly positively correlated with pox (Avipoxvirus) prevalence. Multiple host loci showed significant associations with malaria prevalence after controlling for genome-wide neutral genetic structure. These sites were located near to or within genes linked to metabolism, stress response, transcriptional regulation, complement activity and the inflammatory response, many previously implicated in vertebrate responses to malarial infection. Our findings identify diverse genes - not just limited to the immune system - that may be involved in host protection against malaria and suggest that spatially variable pathogen pressure may be an important evolutionary driver of genetic divergence among wild animal populations, such as Berthelot's pipit. Furthermore, our data indicate that spatio-temporal variation in multiple different pathogens (e.g. malaria and pox in this case) may have to be studied together to develop a more holistic understanding of host pathogen-mediated evolution.


Asunto(s)
Malaria Aviar , Passeriformes , Plasmodium , Animales , Malaria Aviar/epidemiología , Malaria Aviar/genética , Plasmodium/genética , Flujo Genético , Passeriformes/genética , Genotipo
17.
Evol Lett ; 8(1): 18-28, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38370545

RESUMEN

The recognition that climate change is occurring at an unprecedented rate means that there is increased urgency in understanding how organisms can adapt to a changing environment. Wild great tit (Parus major) populations represent an attractive ecological model system to understand the genomics of climate adaptation. They are widely distributed across Eurasia and they have been documented to respond to climate change. We performed a Bayesian genome-environment analysis, by combining local climate data with single nucleotide polymorphisms genotype data from 20 European populations (broadly spanning the species' continental range). We found 36 genes putatively linked to adaptation to climate. Following an enrichment analysis of biological process Gene Ontology (GO) terms, we identified over-represented terms and pathways among the candidate genes. Because many different genes and GO terms are associated with climate variables, it seems likely that climate adaptation is polygenic and genetically complex. Our findings also suggest that geographical climate adaptation has been occurring since great tits left their Southern European refugia at the end of the last ice age. Finally, we show that substantial climate-associated genetic variation remains, which will be essential for adaptation to future changes.

18.
Biol Lett ; 19(9): 20230152, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37727077

RESUMEN

There is considerably greater variation in metabolic rates between men than between women, in terms of basal, activity and total (daily) energy expenditure (EE). One possible explanation is that EE is associated with male sexual characteristics (which are known to vary more than other traits) such as musculature and athletic capacity. Such traits might be predicted to be most prominent during periods of adolescence and young adulthood, when sexual behaviour develops and peaks. We tested this hypothesis on a large dataset by comparing the amount of male variation and female variation in total EE, activity EE and basal EE, at different life stages, along with several morphological traits: height, fat free mass and fat mass. Total EE, and to some degree also activity EE, exhibit considerable greater male variation (GMV) in young adults, and then a decreasing GMV in progressively older individuals. Arguably, basal EE, and also morphometrics, do not exhibit this pattern. These findings suggest that single male sexual characteristics may not exhibit peak GMV in young adulthood, however total and perhaps also activity EE, associated with many morphological and physiological traits combined, do exhibit GMV most prominently during the reproductive life stages.


Asunto(s)
Pubertad , Conducta Sexual , Adolescente , Adulto Joven , Femenino , Humanos , Masculino , Adulto , Reproducción , Metabolismo Energético , Fenotipo
19.
R Soc Open Sci ; 10(9): 230713, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37680495

RESUMEN

Many researchers presume greater variability between female participants than between males due to the menstrual cycle. This view has encouraged a sex bias in health and medical research, resulting in considerable knowledge gaps with important clinical implications. Yet in another field-evolutionary biology-the received wisdom is the reverse: that men are more variable, possibly due to male heterogamety. To test these competing hypotheses, we compared variance between the sexes for 50 morphological and physiological traits, analysing data from the NHANES database. Nearly half the traits did not exhibit sexual dimorphism in variation, while 18 exhibited greater female variation (GFV), indicating GFV does not dominate human characteristics. Only eight traits exhibited greater male variation (GMV), indicating GMV also does not dominate, and in turn offering scant support for the heterogamety hypothesis. When our analysis was filtered to include only women with regular menstrual cycles (and men of equivalent age), the number of traits with GFV and GMV were low and not statistically different, suggesting that the menstrual cycle does not typically explain GFV when it occurs. In practical terms, health and medical researchers should no longer simply assume that female participants will induce additional variation in the traits of interest.

20.
Int J Sports Phys Ther ; 18(4): 800-806, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37547832

RESUMEN

This clinical commentary explores the significance of a comprehensive approach to core training in sports physical therapy, focusing on optimizing performance and minimizing injuries. The core, encompassing multiple regions from the scapula to the glutes and beyond, plays a vital role in athletic performance and injury prevention. The commentary provides a thorough understanding of the various "cores" in the body, highlighting their primary functions and the importance of core stability. The commentary delves into the anatomy of the core, its primary functions, common injuries, and clinical evaluation techniques. It aims to define the role of core stability in athletic activities and discusses the prevalence and characteristics of core injuries in various sports such as baseball, basketball, football, hockey, and soccer. Furthermore, the clinical evaluation section describes subjective and objective assessments, functional testing, and special tests used to identify core injuries and determine their root causes. The author introduces a personalized dynamic core assessment to evaluate multiplanar stabilization and proposes a four-phase intervention program called the "Core Four Pyramid Principles." This program includes activation, stabilization, integration, and perturbation phases, each with specific entry criteria, goals, and targeted exercises. This commentary contributes to the body of literature by providing a comprehensive overview of core training in sports physical therapy, highlighting the significance of a systematic and evidence-based approach, and introducing the "Core Four Pyramid Principles" as a guideline for designing effective core training programs for sports therapists to optimize core function, stability and overall athletic performance while reducing the risk of injuries amongst their athletes.

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