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1.
Planta ; 260(1): 4, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38775846

RESUMO

MAIN CONCLUSION: Natural selection influenced adaptive divergence between Cereus fernambucensis and Cereus insularis, revealing key genes governing abiotic stress responses and supporting neoteny in C. insularis. Uncovering the molecular mechanisms driving adaptive divergence in traits related to habitat adaptation remains a central challenge. In this study, we focused on the cactus clade, which includes Cereus sericifer F.Ritter, Cereus fernambucensis Lem., and Cereus insularis Hemsley. These allopatric species inhabit distinct relatively drier regions within the Brazilian Atlantic Forest, each facing unique abiotic conditions. We leveraged whole transcriptome data and abiotic variables datasets to explore lineage-specific and environment-specific adaptations in these species. Employing comparative phylogenetic methods, we identified genes under positive selection (PSG) and examined their association with non-synonymous genetic variants and abiotic attributes through a PhyloGWAS approach. Our analysis unveiled signatures of selection in all studied lineages, with C. fernambucensis northern populations and C. insularis showing the most PSGs. These PSGs predominantly govern abiotic stress regulation, encompassing heat tolerance, UV stress response, and soil salinity adaptation. Our exclusive observation of gene expression tied to early developmental stages in C. insularis supports the hypothesis of neoteny in this species. We also identified genes associated with abiotic variables in independent lineages, suggesting their role as environmental filters on genetic diversity. Overall, our findings suggest that natural selection played a pivotal role in the geographic range of these species in response to environmental and biogeographic transitions.


Assuntos
Adaptação Fisiológica , Cactaceae , Florestas , Perfilação da Expressão Gênica , Filogenia , Brasil , Cactaceae/genética , Cactaceae/fisiologia , Adaptação Fisiológica/genética , Seleção Genética , Transcriptoma , Estresse Fisiológico/genética , Regulação da Expressão Gênica de Plantas
2.
Plant Physiol ; 192(1): 222-239, 2023 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-36756804

RESUMO

Abscission, known as shattering in crop species, is a highly regulated process by which plants shed parts. Although shattering has been studied extensively in cereals and a number of regulatory genes have been identified, much diversity in the process remains to be discovered. Teff (Eragrostis tef) is a crop native to Ethiopia that is potentially highly valuable worldwide for its nutritious grain and drought tolerance. Previous work has suggested that grain shattering in Eragrostis might have little in common with other cereals. In this study, we characterize the anatomy, cellular structure, and gene regulatory control of the abscission zone (AZ) in E. tef. We show that the AZ of E. tef is a narrow stalk below the caryopsis, which is common in Eragrostis species. X-ray microscopy, scanning electron microscopy, transmission electron microscopy, and immunolocalization of cell wall components showed that the AZ cells are thin walled and break open along with programmed cell death (PCD) at seed maturity, rather than separating between cells as in other studied species. Knockout of YABBY2/SHATTERING1, documented to control abscission in several cereals, had no effect on abscission or AZ structure in E. tef. RNA sequencing analysis showed that genes related to PCD and cell wall modification are enriched in the AZ at the early seed maturity stage. These data show that E. tef drops its seeds using a unique mechanism. Our results provide the groundwork for understanding grain shattering in Eragrostis and further improvement of shattering in E. tef.


Assuntos
Morte Celular , Eragrostis , Grão Comestível/genética , Eragrostis/genética , Sementes/genética
3.
Heredity (Edinb) ; 132(6): 296-308, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38637723

RESUMO

Here we use population genomic data (ddRAD-Seq) and ecological niche modeling to test biogeographic hypotheses for the divergence of the island-endemic cactus species Cereus insularis Hemsl. (Cereeae; Cactaceae) from its sister species C. fernambucensis Lem. The Cereus insularis grows in the Fernando de Noronha Islands (FNI), a Neotropical archipelago located 350 km off the Brazilian Atlantic Forest (BAF) coast. Phylogeographic reconstructions support a northward expansion by the common ancestor of C. insularis and C. fernambucensis along the mainland BAF coast, with C. insularis diverging from the widespread mainland taxon C. fernambucensis after colonizing FNI in the late Pleistocene. The morphologically distinct C. insularis is monophyletic and nested within C. fernambucensis, as expected from a progenitor-derivative speciation model. We tested alternative biogeographic and demographic hypotheses for the colonization of the FNI using Approximate Bayesian Computation. We found the greatest support for a stepping-stone path that emerged during periods of decreased sea level (the "bridge" hypothesis), in congruence with historical ecological niche modeling that shows highly suitable habitats on stepping-stone islands during glacial periods. The outlier analyses reveal signatures of selection in C. insularis, suggesting a putative role of adaptation driving rapid anagenic differentiation of this species in FNI.


Assuntos
Teorema de Bayes , Cactaceae , Ilhas , Filogenia , Filogeografia , Cactaceae/genética , Brasil , Ecossistema , Genética Populacional
4.
Eur J Appl Physiol ; 124(1): 147-218, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37796290

RESUMO

This review is the final contribution to a four-part, historical series on human exercise physiology in thermally stressful conditions. The series opened with reminders of the principles governing heat exchange and an overview of our contemporary understanding of thermoregulation (Part 1). We then reviewed the development of physiological measurements (Part 2) used to reveal the autonomic processes at work during heat and cold stresses. Next, we re-examined thermal-stress tolerance and intolerance, and critiqued the indices of thermal stress and strain (Part 3). Herein, we describe the evolutionary steps that endowed humans with a unique potential to tolerate endurance activity in the heat, and we examine how those attributes can be enhanced during thermal adaptation. The first of our ancestors to qualify as an athlete was Homo erectus, who were hairless, sweating specialists with eccrine sweat glands covering almost their entire body surface. Homo sapiens were skilful behavioural thermoregulators, which preserved their resource-wasteful, autonomic thermoeffectors (shivering and sweating) for more stressful encounters. Following emigration, they regularly experienced heat and cold stress, to which they acclimatised and developed less powerful (habituated) effector responses when those stresses were re-encountered. We critique hypotheses that linked thermoregulatory differences to ancestry. By exploring short-term heat and cold acclimation, we reveal sweat hypersecretion and powerful shivering to be protective, transitional stages en route to more complete thermal adaptation (habituation). To conclude this historical series, we examine some of the concepts and hypotheses of thermoregulation during exercise that did not withstand the tests of time.


Assuntos
Regulação da Temperatura Corporal , Sudorese , Humanos , Regulação da Temperatura Corporal/fisiologia , Aclimatação , Exercício Físico/fisiologia , Estremecimento , Temperatura Alta
5.
Eur J Appl Physiol ; 124(1): 1-145, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37796292

RESUMO

In this third installment of our four-part historical series, we evaluate contributions that shaped our understanding of heat and cold stress during occupational and athletic pursuits. Our first topic concerns how we tolerate, and sometimes fail to tolerate, exercise-heat stress. By 1900, physical activity with clothing- and climate-induced evaporative impediments led to an extraordinarily high incidence of heat stroke within the military. Fortunately, deep-body temperatures > 40 °C were not always fatal. Thirty years later, water immersion and patient treatments mimicking sweat evaporation were found to be effective, with the adage of cool first, transport later being adopted. We gradually acquired an understanding of thermoeffector function during heat storage, and learned about challenges to other regulatory mechanisms. In our second topic, we explore cold tolerance and intolerance. By the 1930s, hypothermia was known to reduce cutaneous circulation, particularly at the extremities, conserving body heat. Cold-induced vasodilatation hindered heat conservation, but it was protective. Increased metabolic heat production followed, driven by shivering and non-shivering thermogenesis, even during exercise and work. Physical endurance and shivering could both be compromised by hypoglycaemia. Later, treatments for hypothermia and cold injuries were refined, and the thermal after-drop was explained. In our final topic, we critique the numerous indices developed in attempts to numerically rate hot and cold stresses. The criteria for an effective thermal stress index were established by the 1930s. However, few indices satisfied those requirements, either then or now, and the surviving indices, including the unvalidated Wet-Bulb Globe-Thermometer index, do not fully predict thermal strain.


Assuntos
Hipotermia , Humanos , Hipotermia/etiologia , Regulação da Temperatura Corporal/fisiologia , Temperatura Baixa , Temperatura Corporal/fisiologia , Exercício Físico/fisiologia
6.
Ann Bot ; 132(5): 989-1006, 2023 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-37815357

RESUMO

BACKGROUND AND AIMS: Cactaceae are succulent plants, quasi-endemic to the American continent, and one of the most endangered plant groups in the world. Molecular phylogenies have been key to unravelling phylogenetic relationships among major cactus groups, previously hampered by high levels of morphological convergence. Phylogenetic studies using plastid markers have not provided adequate resolution for determining generic relationships within cactus groups. This is the case for the tribe Cereeae s.l., a highly diverse group from tropical America. Here we aimed to reconstruct a well-resolved phylogenetic tree of tribe Cereeae and update the circumscription of suprageneric and generic groups in this tribe. METHODS: We integrated sequence data from public gene and genomic databases with new target sequences (generated using the customized Cactaceae591 probe set) across representatives of this tribe, with a denser taxon sampling of the subtribe Cereinae. We inferred concatenated and coalescent phylogenetic trees and compared the performance of both approaches. KEY RESULTS: Six well-supported suprageneric clades were identified using different datasets. However, only genomic datasets, especially the Cactaceae591, were able to resolve the contentious relationships within the subtribe Cereinae. CONCLUSIONS: We propose a new taxonomic classification within Cereeae based on well-resolved clades, including new subtribes (Aylosterinae subtr. nov., Uebelmanniinae subtr. nov. and Gymnocalyciinae subtr. nov.) and revised subtribes (Trichocereinae, Rebutiinae and Cereinae). We emphasize the importance of using genomic datasets allied with coalescent inference to investigate evolutionary patterns within the tribe Cereeae.


Assuntos
Evolução Biológica , Cactaceae , Filogenia , Análise de Sequência de DNA , Genômica , Cactaceae/genética
7.
Am J Bot ; 110(3): 1-17, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36708517

RESUMO

PREMISE: Pilosocereus (Cactaceae) is an important dry forest element in all subregions and transitional zones of the neotropics, with the highest diversity in eastern Brazil. The genus is subdivided into informal taxonomic groups; however, most of these are not supported by recent molecular phylogenetic inferences. This lack of confidence is probably due to the use of an insufficient number of loci and the complexity of cactus diversification. Here, we explored the species relationships in Pilosocereus in more detail, integrating multilocus phylogenetic approaches with the assessment of the ancestral range and the effect of geography on diversification shifts. METHODS: We used 28 nuclear, plastid, and mitochondrial loci from 54 plant samples of 31 Pilosocereus species for phylogenetic analyses. We used concatenated and coalescent phylogenetic trees and Bayesian models to estimate the most likely ancestral range and diversification shifts. RESULTS: All Pilosocereus species were clustered in the same branch, except P. bohlei. The phylogenetic relationships were more associated with the geographic distribution than taxonomic affinities among taxa. The genus began diversifying during the Plio-Pleistocene transition in the Caatinga domain and experienced an increased diversification rate during the Calabrian age. CONCLUSIONS: We recovered a well-supported multispecies coalescent phylogeny. Our results refine the pattern of rapid diversification of Pilosocereus species across neotropical drylands during the Pleistocene and highlight the need for taxonomic rearrangements in the genus. We recovered a pulse of diversification during the Pleistocene that was likely driven by multiple dispersal and vicariance events within and among the Caatinga, Cerrado, and Atlantic Forest domains.


Assuntos
Florestas , Filogenia , Filogeografia , Teorema de Bayes , Brasil
8.
Eur J Appl Physiol ; 123(11): 2379-2459, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37702789

RESUMO

This contribution is the first of a four-part, historical series encompassing foundational principles, mechanistic hypotheses and supported facts concerning human thermoregulation during athletic and occupational pursuits, as understood 100 years ago and now. Herein, the emphasis is upon the physical and physiological principles underlying thermoregulation, the goal of which is thermal homeostasis (homeothermy). As one of many homeostatic processes affected by exercise, thermoregulation shares, and competes for, physiological resources. The impact of that sharing is revealed through the physiological measurements that we take (Part 2), in the physiological responses to the thermal stresses to which we are exposed (Part 3) and in the adaptations that increase our tolerance to those stresses (Part 4). Exercising muscles impose our most-powerful heat stress, and the physiological avenues for redistributing heat, and for balancing heat exchange with the environment, must adhere to the laws of physics. The first principles of internal and external heat exchange were established before 1900, yet their full significance is not always recognised. Those physiological processes are governed by a thermoregulatory centre, which employs feedback and feedforward control, and which functions as far more than a thermostat with a set-point, as once was thought. The hypothalamus, today established firmly as the neural seat of thermoregulation, does not regulate deep-body temperature alone, but an integrated temperature to which thermoreceptors from all over the body contribute, including the skin and probably the muscles. No work factor needs to be invoked to explain how body temperature is stabilised during exercise.


Assuntos
Regulação da Temperatura Corporal , Temperatura Cutânea , Humanos , Regulação da Temperatura Corporal/fisiologia , Homeostase , Pele , Exercício Físico/fisiologia
9.
Eur J Appl Physiol ; 123(12): 2587-2685, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37796291

RESUMO

In this, the second of four historical reviews on human thermoregulation during exercise, we examine the research techniques developed by our forebears. We emphasise calorimetry and thermometry, and measurements of vasomotor and sudomotor function. Since its first human use (1899), direct calorimetry has provided the foundation for modern respirometric methods for quantifying metabolic rate, and remains the most precise index of whole-body heat exchange and storage. Its alternative, biophysical modelling, relies upon many, often dubious assumptions. Thermometry, used for >300 y to assess deep-body temperatures, provides only an instantaneous snapshot of the thermal status of tissues in contact with any thermometer. Seemingly unbeknownst to some, thermal time delays at some surrogate sites preclude valid measurements during non-steady state conditions. To assess cutaneous blood flow, immersion plethysmography was introduced (1875), followed by strain-gauge plethysmography (1949) and then laser-Doppler velocimetry (1964). Those techniques allow only local flow measurements, which may not reflect whole-body blood flows. Sudomotor function has been estimated from body-mass losses since the 1600s, but using mass losses to assess evaporation rates requires precise measures of non-evaporated sweat, which are rarely obtained. Hygrometric methods provide data for local sweat rates, but not local evaporation rates, and most local sweat rates cannot be extrapolated to reflect whole-body sweating. The objective of these methodological overviews and critiques is to provide a deeper understanding of how modern measurement techniques were developed, their underlying assumptions, and the strengths and weaknesses of the measurements used for humans exercising and working in thermally challenging conditions.


Assuntos
Regulação da Temperatura Corporal , Sudorese , Humanos , Regulação da Temperatura Corporal/fisiologia , Temperatura Corporal/fisiologia , Pele/irrigação sanguínea , Exercício Físico/fisiologia , Temperatura Alta
10.
An Acad Bras Cienc ; 95(suppl 1): e20220460, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37646712

RESUMO

Cereus jamacaru is a cactus distributed in Northeastern Brazil, with high symbolic value to this region. However, the interaction, behavior and the role of pollinators remains poorly understood. Here, we investigate the reproductive biology, addressing the ecological significance of floral attributes, including details about floral signaling. The study was carried at three areas of the Caatinga, in 2015, 2017 and 2021. We analyzed the floral morphometry, volume and concentration of the nectar, and characterized the colour and scent of flowers. Additionally, we described the pollinator behavior and performed controlled pollination experiments. The 'Mandacaru' is self-incompatible, has nocturnal anthesis and the nectar is accumulated as droplets in a long hypanthial tube. The flowers have a reflective pattern with a dark outer surface and a white inner surface. (E)-nerolidol is the major component (87.4%) of its floral perfume. We registered the sphingid moth Cocytius antaeus visiting the flowers. The floral attributes, attractants and rewards drives to a sphingophily, and the pollination treatments showed the dependence to fruit set by C. antaeus, the pollinator registered. In this case, if the apparent lack of pollinator diversity encompasses its entire range, the loss of the hawkmoth could severely impact the reproductive success of the cactus.


Assuntos
Cactaceae , Brasil , Florestas , Néctar de Plantas
11.
Plant Mol Biol ; 109(3): 283-299, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32270429

RESUMO

KEY MESSAGE: Among the five cassava isoforms (MeAPL1-MeAPL5), MeAPL3 is responsible for determining storage root starch content. Degree of storage root postharvest physiological deterioration (PPD) is directly correlated with starch content. AGPase is heterotetramer composed of two small and two large subunits each coded by small gene families in higher plants. Studies in cassava (Manihot esculenta) identified and characterized five isoforms of Manihot esculenta ADP-glucose pyrophosphorylase large subunit (MeAPL1-MeAPL5) and employed virus induced gene silencing (VIGS) to show that MeAPL3 is the key isoform responsible for starch and dry matter accumulation in cassava storage roots. Silencing of MeAPL3 in cassava through stable transgenic lines resulted in plants displaying significant reduction in storage root starch and dry matter content (DMC) and induced a distinct phenotype associated with increased petiole/stem angle, resulting in a droopy leaf phenotype. Plants with reduced starch and DMC also displayed significantly reduced or no postharvest physiological deterioration (PPD) compared to controls and lines with high DMC and starch content. This provides strong evidence for direct relationships between starch/dry matter content and its role in PPD and canopy architecture traits in cassava.


Assuntos
Manihot , Manihot/genética , Folhas de Planta/genética , Raízes de Plantas/fisiologia , Amido
12.
Plant Mol Biol ; 109(3): 271-282, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34825349

RESUMO

KEY MESSAGE: Cassava genetic transformation has mostly been reported for African cassava varieties, but not for Asian varieties. This is the first report of cassava transformation in Asian elite varieties using friable embryogenic calli. Agrobacterium-mediated cassava transformation via friable embryogenic calli (FEC) has enabled the robust production of transgenic cassava. So far, mostly the model cassava variety 60444 and African varieties have been transformed because of their good production and regeneration from embryogenic tissues. It is important to develop transformation methods for elite Asian cassava varieties to meet the changing needs in one of the world's major cassava production areas. However, a suitable transformation method for the Asian elite variety Kasetsart 50 (KU50) has not been developed. Here, we report a transformation method for KU50, the cultivar with the highest planting area in Thailand and Vietnam. In cassava transformation, the preparation of FEC as the target tissue for transgene integration is a key step. FEC induction from KU50 was improved by using media with reduced nutrients and excess vitamin B1, and somatic embryo and plant regeneration optimized by manipulation of naphthalene acetic acid (NAA), and benzylamino purine (BAP). The transformation efficiency for KU50 was 22%, approximately half that of 60444 at 45%. Transcriptome analysis indicated that the expression of genes related to cell-wall loosening was upregulated in FEC from KU50 compared with 60444, indicating that cell-wall production and assembly were disproportionate in the Asian variety. The transformation system for KU50 reported here will contribute to the molecular breeding of cassava plants for Asian farmers using transgenic and genome-editing technologies.


Assuntos
Manihot , Agrobacterium/genética , Manihot/genética , Plantas Geneticamente Modificadas/genética , Transformação Genética , Transgenes
13.
Plant Biotechnol J ; 20(9): 1716-1729, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35560779

RESUMO

Tef is a staple food and a valuable cash crop for millions of people in Ethiopia. Lodging is a major limitation to tef production, and for decades, the development of lodging resistant varieties proved difficult with conventional breeding approaches. We used CRISPR/Cas9 to introduce knockout mutations in the tef orthologue of the rice SEMIDWARF-1 (SD-1) gene to confer semidwarfism and ultimately lodging resistance. High frequency recovery of transgenic and SD-1 edited tef lines was achieved in two tef cultivars by Agrobacterium-mediated delivery into young leaf explants of gene editing reagents along with transformation and regeneration enhancing morphogenic genes, BABY BOOM (BBM) and WUSCHEL2 (WUS2). All of the 23 lines analyzed by next-generation sequencing had at least two or more alleles of SD-1 mutated. Of these, 83% had tetra-allelic frameshift mutations in the SD-1 gene in primary tef regenerants, which were inherited in subsequent generations. Phenotypic data generated on T1 and T2 generations revealed that the sd-1 lines have reduced culm and internode lengths with no reduction in either panicle or peduncle lengths. These characteristics are comparable with rice sd-1 plants. Measurements of lodging, in greenhouse-grown plants, showed that sd-1 lines have significantly higher resistance to lodging at the heading stage compared with the controls. This is the first demonstration of the feasibility of high frequency genetic transformation and CRISPR/Cas9-mediated genome editing in this highly valuable but neglected crop. The findings reported here highlight the potential of genome editing for the improvement of lodging resistance and other important traits in tef.


Assuntos
Eragrostis , Genes de Plantas , Alelos , Sistemas CRISPR-Cas , Eragrostis/genética , Edição de Genes , Mutação , Melhoramento Vegetal , Plantas Geneticamente Modificadas/genética
14.
Plant Biotechnol J ; 19(4): 844-854, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33190345

RESUMO

Delivering the benefits of agricultural biotechnology to smallholder farmers requires that resources be directed towards staple food crops. To achieve effect at scale, beneficial traits must be integrated into multiple, elite farmer-preferred varieties with relevance across geographical regions. The staple root crop cassava (Manihot esculenta) is consumed for dietary calories by more than 800 million people, but its tuberous roots provide insufficient iron and zinc to meet nutritional needs. In Africa, cassava yields are furthermore limited by the virus diseases, cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). In this study, we strove to develop cassava displaying high-level resistance to CBSD and CMD to attain food and economic security for cassava farmers, along with biofortified levels of iron and zinc to enhance consumer health. RNAi-mediated technology was used to achieve resistance to CBSD in two East African and one Nigerian farmer-preferred cultivars that harboured resistance to CMD. The Nigerian cvs. TMS 95/0505 and TMS 91/02324 were modified with T-DNA imparting resistance to CBSD, along with AtIRT1 (major iron transporter) and AtFER1 (ferritin) transgenes to achieve nutritionally significant levels of iron and zinc in cassava storage roots (145 and 40 µg/g dry weight, respectively). The inherent resistance to CMD was maintained in all four disease resistant and mineral enhanced cassava cultivars described here, demonstrating that this technique could be deployed across multiple farmer-preferred varieties to benefit the food and nutritional security of consumers in Africa.


Assuntos
Manihot , África , Biofortificação , Resistência à Doença/genética , Humanos , Manihot/genética , Minerais , Doenças das Plantas
15.
Eur J Appl Physiol ; 121(1): 193-208, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33011890

RESUMO

PURPOSE: In tachymetabolic species, metabolic rate increases disproportionately with body mass, and that inter-specific relationship is typically modelled allometrically. However, intra-specific analyses are less common, particularly for healthy humans, so the possibility that human metabolism would also scale allometrically was investigated. METHODS: Basal metabolic rate was determined (respirometry) for 68 males (18-40 years; 56.0-117.1 kg), recruited across five body-mass classes. Data were collected during supine, normothermic rest from well-rested, well-hydrated and post-absorptive participants. Linear and allometric regressions were applied, and three scaling methods were assessed. Data from an historical database were also analysed (2.7-108.9 kg, 4811 males; 2.0-96.4 kg, 2364 females). RESULTS: Both linear and allometric functions satisfied the statistical requirements, but not the biological pre-requisite of an origin intercept. Mass-independent basal metabolic data beyond the experimental mass range were not achieved using linear regression, which yielded biologically impossible predictions as body mass approached zero. Conversely, allometric regression provided a biologically valid, powerful and statistically significant model: metabolic rate = 0.739 * body mass0.547 (P < 0.05). Allometric analysis of the historical male data yielded an equivalent, and similarly powerful model: metabolic rate = 0.873 * body mass0.497 (P < 0.05). CONCLUSION: It was established that basal and resting metabolic rates scale allometrically with body mass in humans from 10-117 kg, with an exponent of 0.50-0.55. It was also demonstrated that ratiometric scaling yielded invalid metabolic predictions, even within the relatively narrow experimental mass range. Those outcomes have significant physiological implications, with applications to exercising states, modelling, nutrition and metabolism-dependent pharmacological prescriptions.


Assuntos
Metabolismo Basal , Variação Biológica da População , Adolescente , Adulto , Temperatura Corporal , Peso Corporal , Interpretação Estatística de Dados , Exercício Físico , Humanos , Masculino , Padrões de Referência , Decúbito Dorsal
16.
Eur J Appl Physiol ; 121(10): 2925-2938, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34212218

RESUMO

PURPOSE: The first aim of this experiment was to evaluate the appropriateness of linear and non-linear (allometric) models to scale peak aerobic power (oxygen consumption) against body mass. The possibilities that oxygen consumption would scale allometrically across the complete metabolic range, and that the scaling exponents would differ significantly between basal and maximal-exercise states, were then evaluated. It was further hypothesised that the scaling exponent would increase in a stepwise manner with elevations in exercise intensity. Finally, the utility of applying the scaling exponent derived for peak aerobic power to another population sample was evaluated. METHODS: Basal, steady-state walking and peak (treadmill) oxygen-consumption data were measured using 60 relatively homogeneous men (18-40 year; 56.0-117.1 kg), recruited across five mass classes. Linear and allometric regressions were applied, with the utility of each scaling method evaluated. RESULTS: Oxygen consumption scaled allometrically with body mass across the complete metabolic range, and was always superior to both ratiometric analysis and linear regression. The scaling exponent increased significantly from rest (mass0.57) to maximal exercise (mass0.75; P < 0.05), but not between steady-state walking (mass0.87) and maximal exercise (P > 0.05). When used with an historical database, the maximal-exercise exponent successfully removed the mass bias. CONCLUSION: It has been demonstrated that the oxygen consumption of healthy humans scales allometrically with body mass across the entire metabolic range. Moreover, only two scaling exponents (rest and exercise) were required to produce mass-independent outcomes from those data. Accordingly, ratiometric and linear regression analyses are not recommended as scaling methods.


Assuntos
Exercício Físico/fisiologia , Consumo de Oxigênio/fisiologia , Corrida/fisiologia , Caminhada/fisiologia , Adolescente , Adulto , Metabolismo Basal/fisiologia , Peso Corporal/fisiologia , Teste de Esforço , Humanos , Adulto Jovem
17.
J Therm Biol ; 97: 102858, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33863427

RESUMO

The Asia-Pacific contains over half of the world's population, 21 countries have a Gross Domestic Product <25% of the world's largest economy, many countries have tropical climates and all suffer the impact of global warming. That 'perfect storm' exacerbates the risk of occupational heat illness, yet first responders must perform physically demanding work wearing personal-protective clothing and equipment. Unfortunately, the Eurocentric emphasis of past research has sometimes reduced its applicability to other ethnic groups. To redress that imbalance, relevant contemporary research has been reviewed, to which has been added information applicable to people of Asian, Melanesian and Polynesian ancestry. An epidemiological triad is used to identify the causal agents and host factors of work intolerance within hot-humid climates, commencing with the size dependency of resting metabolism and heat production accompanying load carriage, followed by a progression from the impact of single-layered clothing through to encapsulating ensembles. A morphological hypothesis is presented to account for inter-individual differences in heat production and heat loss, which seems to explain apparent ethnic- and gender-related differences in thermoregulation, at least within thermally compensable states. The mechanisms underlying work intolerance, cardiovascular insufficiency and heat illness are reviewed, along with epidemiological data from the Asia-Pacific. Finally, evidence-based preventative and treatment strategies are presented and updated concerning moisture-management fabrics and barriers, dehydration, pre- and post-exercise cooling, and heat adaptation. An extensive reference list is provided, with >25 recommendations enabling physiologists, occupational health specialists, policy makers, purchasing officers and manufacturers to rapidly extract interpretative outcomes pertinent to the Asia-Pacific.


Assuntos
Aquecimento Global , Resposta ao Choque Térmico , Estresse Ocupacional , Roupa de Proteção , Ásia , Humanos
18.
J Cancer Educ ; 36(6): 1285-1289, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-32448924

RESUMO

The aim of this study was to assess the levels of awareness of oral cancer in healthcare staff at a district general hospital in the UK. This excluded those staff involved in head and neck cancer management. The study identified the areas where there was a deficiency in knowledge and quantified any differences across the professions. Following a literature review utilising the National Institute for Health and Care Excellence (NICE) Healthcare Databases Advanced Research (HDAS) tool, a questionnaire was designed, which was piloted amongst healthcare professionals on one ward. The feedback from the respondents was used to test the suitability of the survey format and modified before implementation across the hospital. One hundred fifty-five completed surveys were collected. The respondents were divided into doctors, nursing staff, and healthcare assistants (HCAs). There were generally low to middle levels of subjective individual confidence in identifying oral cancer. There was confusion on the clinical signs of oral cancer, with 29% of respondents believing that toothache was a sign. Almost half of all the respondents believed that dental decay was a risk factor for oral cancer. Although the significance of an early diagnosis was recognised as being important, a number of respondents were not aware of the likely differences in morbidity and mortality based on the stage of disease on diagnosis. This study has demonstrated that the healthcare workforce has gaps in knowledge both in of the presentation of oral cancer and the morbidity and mortality associated with a delay in diagnosis. Further learning opportunities for all healthcare staff will help to reduce future disease burden.


Assuntos
Hospitais Gerais , Neoplasias Bucais , Atenção à Saúde , Pessoal de Saúde , Humanos , Neoplasias Bucais/diagnóstico , Reino Unido
19.
Reg Environ Change ; 21(2): 33, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33776560

RESUMO

Wetlands are critically important for biodiversity and human wellbeing, but face a range of challenges. This is especially true in the Mediterranean region, where wetlands support endemic and threatened species and remain integral to human societies, but have been severely degraded in recent decades. Here, in order to raise awareness of future challenges and opportunities for Mediterranean wetlands, and to inform proactive research and management, we identified (a) 50 key issues that might affect Mediterranean wetlands between 2020 and 2050, and (b) 50 important research questions that, if answered, would have the greatest impact on the conservation of Mediterranean wetlands between 2020 and 2050. We gathered ideas through an online survey and review of recent literature. A diverse assessment panel prioritised ideas through an iterative, anonymised, Delphi-like process of scoring, voting and discussion. The prioritised issues included some that are already well known but likely to have a large impact on Mediterranean wetlands in the next 30 years (e.g. the accumulation of dams and reservoirs, plastic pollution and weak governance), and some that are currently overlooked in the context of Mediterranean wetlands (e.g. increasing desalination capacity and development of antimicrobial resistance). Questions largely focused on how best to carry out conservation interventions, or understanding the impacts of threats to inform conservation decision-making. This analysis will support research, policy and practice related to environmental conservation and sustainable development in the Mediterranean, and provides a model for similar analyses elsewhere in the world. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10113-020-01743-1.

20.
Mol Phylogenet Evol ; 151: 106896, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32562821

RESUMO

The reconstruction of relationships within recently radiated groups is challenging even when massive amounts of sequencing data are available. The use of restriction site-associated DNA sequencing (RAD-Seq) to this end is promising. Here, we assessed the performance of RAD-Seq to infer the species-level phylogeny of the rapidly radiating genus Cereus (Cactaceae). To examine how the amount of genomic data affects resolution in this group, we used datasets and implemented different analyses. We sampled 52 individuals of Cereus, representing 18 of the 25 species currently recognized, plus members of the closely allied genera Cipocereus and Praecereus, and other 11 Cactaceae genera as outgroups. Three scenarios of permissiveness to missing data were carried out in iPyRAD, assembling datasets with 30% (333 loci), 45% (1440 loci), and 70% (6141 loci) of missing data. For each dataset, Maximum Likelihood (ML) trees were generated using two supermatrices, i.e., only SNPs and SNPs plus invariant sites. Accuracy and resolution were improved when the dataset with the highest number of loci was used (6141 loci), despite the high percentage of missing data included (70%). Coalescent trees estimated using SVDQuartets and ASTRAL are similar to those obtained by the ML reconstructions. Overall, we reconstruct a well-supported phylogeny of Cereus, which is resolved as monophyletic and composed of four main clades with high support in their internal relationships. Our findings also provide insights into the impact of missing data for phylogeny reconstruction using RAD loci.


Assuntos
Evolução Biológica , Cactaceae/genética , Genoma de Planta , Análise de Sequência de DNA , Sequência de Bases , Bases de Dados Genéticas , Loci Gênicos , Especiação Genética , Funções Verossimilhança , Filogenia , Polimorfismo de Nucleotídeo Único/genética , Análise de Componente Principal
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