Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 14.667
Filtrar
1.
Gene ; 764: 145090, 2021 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-32861880

RESUMO

Litopenaeus vannamei (L. vannamei) is one of the most widely cultured shrimp species in the world. The species often suffers from cold stress. To understand the molecular mechanism of cold tolerance, we performed transcriptomic analysis on two contrasting cultivars of L. vannamei, namely, cold-tolerant Guihai 2 (GH2) and cold-sensitive Guihai1 (GH1), under a control temperature (28 °C), cold stress (16 °C), and recovery to 28 °C. A total of 84.5 Gb of sequences were generated from 12 L. vannamei hepatopancreas libraries. The de-novo assembly generated a total of 143,029 unigenes with a mean size of 1,052 bp and an N50 of 2,604 bp, of which 34.08% were annotated in the Nr database. We analyzed the differentially expressed genes (DEGs) between nine comparison groups and detected a total of 21,026 DEGs. KEGG pathways, including lysosome, sphingolipid metabolism and nitrogen metabolism, were significantly enriched by DEGs between different temperatures in GH2. Furthermore, eight of the most significantly DEGs under cold stress from the transcriptomic analysis were selected for quantitative real-time PCR (qPCR) validation. Overall, we compared gene expression changes under cold stress in cold-tolerant and cold-sensitive L. vannamei for the first time. The results may further extend our understanding of the cold stress-response mechanism in L. vannamei.


Assuntos
Aclimatação/genética , Resposta ao Choque Frio/genética , Hepatopâncreas/metabolismo , Penaeidae/fisiologia , Frutos do Mar , Animais , Aquicultura , China , Temperatura Baixa/efeitos adversos , Regulação da Expressão Gênica/fisiologia , Anotação de Sequência Molecular , RNA-Seq , Reação em Cadeia da Polimerase em Tempo Real , Transcriptoma/genética
2.
Gene ; 764: 145097, 2021 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-32866589

RESUMO

Tomato (Lycopersicon esculentum Mill) is an important food plant that has been used as a model plant in genetic evolution and molecular biology research. The plant is originated from the tropics; thus, it is sensitive to cold. Its growth and development can be easily affected by cold stress. In this study, cold-regulated gene LeCOR413PM2 was cloned from tomato leaves and then used to generate two types of transgenic tomato plants: LeCOR413PM2-overexpressing transgenic plants and RNA-interference-expressing transgenic plants. The functions and expression of LeCOR413PM2 gene in response to cold stress were subsequently assessed. The results showed that LeCOR413PM2 localized in the plasma membrane. Expression of LeCOR413PM2 gene in the leaf of transgenic tomato plant was highest compared to that in other organs (i.e., root, stem, flower and fruit); it was elevated when plants were treated with cold stress. Overexpression of LeCOR413PM2 gene was found to not only reduce damage to cell membrane, accumulation of ROS, and photoinhibition of PSII, but also maintain high activity of antioxidant enzymes and content of osmotic regulators. The results also reveal that high activities of antioxidant enzymes were caused by the up-regulation of their gene expressions. This study demonstrates that the overexpression of LeCOR413PM2 could increase cold tolerance of transgenic tomato plants, while the suppressed expression of LeCOR413PM2 by RNA interference could increase the sensitivity of plants to cold.


Assuntos
Aclimatação/genética , Resposta ao Choque Frio/genética , Regulação da Expressão Gênica de Plantas , Lycopersicon esculentum/fisiologia , Proteínas de Plantas/genética , Membrana Celular/metabolismo , Clonagem Molecular , Temperatura Baixa/efeitos adversos , Genes de Plantas , Osmose/fisiologia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Interferência de RNA , Espécies Reativas de Oxigênio/metabolismo
3.
Mar Environ Res ; 162: 105192, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33142110

RESUMO

Predicting responses of marine organisms to global change requires eco-physiological assessments across the complex life cycles of species. Here, we experimentally tested the vulnerability of a demersal temperate fish (Sparus aurata) to long-lasting heatwaves, on larval, juvenile and adult life-stages. Fish were exposed to simulated coastal (18 °C), estuarine (24 °C) summer temperatures, and heatwave conditions (30 °C) and their physiological responses were assessed based on cellular stress response biomarkers (heat shock protein 70 kDa, ubiquitin, antioxidant enzymes, lipid peroxidation) and phenotypic measures (histopathology, condition and mortality). Life-stage vulnerability can be ranked as larvae > adults > juveniles, based on mortality, tissue pathology and the capacity to employ cellular stress responses, reflecting the different environmental niches of each life stage. While larvae lacked acclimation capacity, which resulted in damage to tissues and elevated mortality, juveniles coped well with elevated temperature. The rapid induction of cytoprotective proteins maintained the integrity of vital organs in juveniles, suggesting adaptive phenotypic plasticity in coastal and estuarine waters. Adults displayed lower plasticity to heatwaves as they transition to deeper habitats for maturation, showing tissue damage in brain, liver and muscle. Life cycle closure of sea breams in coastal habitats will therefore be determined by larval and adult stages.


Assuntos
Aclimatação , Dourada , Adaptação Fisiológica , Animais , Estágios do Ciclo de Vida , Temperatura
4.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 1962-1965, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018387

RESUMO

Subretinal stimulators help restoring vision to blind people, suffering from degenerative eye diseases. This work aims to reduce patient's efforts to continuously tune his device, by implementing a physiological ambient illumination adaptation system. The parameters of the adaptation to changing illumination conditions are highly customizable, to best fit individual patients requirements.


Assuntos
Iluminação , Próteses Visuais , Aclimatação , Adaptação Fisiológica , Humanos , Visão Ocular
5.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5884-5887, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019313

RESUMO

Predicting one's mood, health, and stress in the future may provide useful feedback before wellbeing related problems become severe. Previously, researchers developed participant-dependent wellbeing prediction models using mobile and wearable sensors, where the models were trained and tested with the same group of people. However, in real-world applications, it is essential to consider the adaptability of the developed models to new users for predicting new users' wellbeing immediately and accurately. In this paper, we built wellbeing prediction models using passively sensed data from wearable sensors, mobile phones, and weather API, and deep learning methods, and evaluated the models with the data from new users. We compared deep long short-term memory (LSTM) network and the combination of convolutional neural network (CNN) and the LSTM model. We found that our deep LSTM model provided performances, in mean absolute error (MAE), as 15.7, 15.6, and 16.8 out of 100 in predicting self-reported mood, health, and stress respectively for new users. Furthermore, we applied a fine-tuning transfer learning method based on our deep LSTM model, which provided new participants with more accurate predictions, especially when the volume of new participants' data was limited. The transfer learning model improved the MAE performances to 13.5, 13.2, and 14.4 out of 100 for mood, health, and stress, respectively.


Assuntos
Aprendizado Profundo , Redes Neurais de Computação , Aclimatação , Previsões , Humanos
6.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5913-5916, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019320

RESUMO

With the quick development of dry electrode electroencephalography (EEG) acquisition technology, EEG-based sleep quality evaluation attracts more attention for its objective and quantitative merits. However, there hasn't been a standard experimental paradigm. This situation hinders the development of sleep quality evaluation method and technique. In this paper, we experimentally examine the performance of four typical experimental paradigms for EEG-based sleep quality evaluation and develop a new EEG dataset recorded by dry-electrode headset. To eliminate individual variation caused by subjects, we evaluate the four experimental paradigms using domain adaptation (DA) methods. Experimental results demonstrate that a relaxing paradigm is more effective than other attention concentration paradigms and achieves the average accuracy of 76.01%. Domain Adversarial Neural Network outperforms other DA methods and obtains 18.69% improvement on accuracy compared with transfer component analysis.


Assuntos
Aclimatação , Eletroencefalografia , Eletrodos , Redes Neurais de Computação , Sono
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 674-677, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018077

RESUMO

Before the operation of a biosignal-based application, long-duration calibration is required to adjust the pre-trained classifier to a new user data (target data). For reducing such time-consuming step, linear domain adaptation (DA) transfer learning approaches, which transfer pooled data (source data) related to the target data, are highlighted. In the last decade, they have been applied to surface electromyogram (sEMG) data with the implicit assumption that sEMG data are linear. However, sEMGs typically have non-linear characteristics, and due to the discrepancy between the assumption and actual characteristics, linear DA approaches would cause a negative transfer. This study investigated how the correlation between the source and target data affects an 8-class forearm movement classification after applying linear DA approaches. As a result, we found significant positive correlations between the classification accuracy and the source-target correlation. Additionally, the source-target correlation depended on the motion class. Therefore, our results suggest that we should choose a non-linear DA approach when the source-target correlation among subjects or motion classes is low.


Assuntos
Algoritmos , Movimento , Aclimatação , Eletromiografia , Humanos , Movimento (Física)
9.
Nat Commun ; 11(1): 4928, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-33004791

RESUMO

High-altitude adaptation of Tibetans represents a remarkable case of natural selection during recent human evolution. Previous genome-wide scans found many non-coding variants under selection, suggesting a pressing need to understand the functional role of non-coding regulatory elements (REs). Here, we generate time courses of paired ATAC-seq and RNA-seq data on cultured HUVECs under hypoxic and normoxic conditions. We further develop a variant interpretation methodology (vPECA) to identify active selected REs (ASREs) and associated regulatory network. We discover three causal SNPs of EPAS1, the key adaptive gene for Tibetans. These SNPs decrease the accessibility of ASREs with weakened binding strength of relevant TFs, and cooperatively down-regulate EPAS1 expression. We further construct the downstream network of EPAS1, elucidating its roles in hypoxic response and angiogenesis. Collectively, we provide a systematic approach to interpret phenotype-associated noncoding variants in proper cell types and relevant dynamic conditions, to model their impact on gene regulation.


Assuntos
Aclimatação/genética , Cromatina/metabolismo , Grupos Étnicos/genética , Redes Reguladoras de Genes , Modelos Genéticos , Altitude , Doença da Altitude/etnologia , Doença da Altitude/genética , Doença da Altitude/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Hipóxia Celular/genética , Células Cultivadas , Cromatina/genética , Sequenciamento de Cromatina por Imunoprecipitação , Resistência à Doença/genética , Feminino , Regulação da Expressão Gênica , Células Endoteliais da Veia Umbilical Humana , Humanos , Hipóxia/genética , Hipóxia/metabolismo , Oxigênio/metabolismo , Polimorfismo de Nucleotídeo Único , Gravidez , Cultura Primária de Células , RNA-Seq , Elementos Reguladores de Transcrição/genética , Seleção Genética , Tibet/etnologia , Fatores de Transcrição/metabolismo , Sequenciamento Completo do Genoma
10.
Nat Commun ; 11(1): 5069, 2020 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-33093493

RESUMO

Ongoing climate change is predicted to trigger major shifts in the geographic distribution of marine plankton species. However, it remains unclear whether species will successfully track optimal habitats to new regions, or face extinction. Here we show that one significant zooplankton group, the radiolaria, underwent a severe decline in high latitude species richness presaged by ecologic reorganization during the late Neogene, a time of amplified polar cooling. We find that the majority (71%) of affected species did not relocate to the warmer low latitudes, but went extinct. This indicates that some plankton species cannot track optimal temperatures on a global scale as assumed by ecologic models; instead, assemblages undergo restructuring and extinction once local environmental thresholds are exceeded. This pattern forewarns profound diversity loss of high latitude radiolaria in the near future, which may have cascading effects on the ocean food web and carbon cycle.


Assuntos
Mudança Climática/história , Ecossistema , Rhizaria/fisiologia , Zooplâncton/fisiologia , Aclimatação/fisiologia , Animais , Regiões Antárticas , Biodiversidade , Evolução Biológica , Extinção Biológica , História Antiga , Modelos Biológicos , Oceanos e Mares , Oceano Pacífico , Temperatura
11.
Sci Total Environ ; 748: 141346, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33113687

RESUMO

Demographic trends will play a role in determining the magnitude of climate disruption and the ability of societies to adapt to it. Yet policy makers largely ignore the potential of fertility changes and population growth when designing policies to limit climate disruption and lessen its impacts. Here we argue that rights-based policy interventions could decrease fertility rates to levels consistent with low population pathways. We review country and global level studies that explore the effects of low population pathways on climate change mitigation and adaptation. We then provide rights-based policy recommendations, such as the expansion of voluntary family planning programs that incorporate elements from successful past programs, and highlight current research gaps. In concert with policies that end fossil fuel use and incentivize sustainable consumption, humane policies that slow population growth should be part of a multifaceted climate response. These policies require attention from scientists, policy analysts and politicians.


Assuntos
Mudança Climática , Crescimento Demográfico , Aclimatação , Coeficiente de Natalidade , Fertilidade
12.
Mar Environ Res ; 162: 105180, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33126112

RESUMO

The intertidal zone is an especially stressful thermal habitat, typically exposing residents to air temperatures for up to 6 h at a time, twice daily. Tolerance to elevated temperatures has been particularly well-studied for a variety of intertidal species, especially with regard to upper thermal limits during summers. However, in recent years, as climates have been changing around the world, temperate zone intertidal organisms have sometimes been exposed to periods of unusually high air temperatures during the winter. The present study sought to examine the impact of elevated temperatures on survival and clearance rates of winter-acclimated intertidal individuals of the sedentary marine suspension-feeding gastropod Crepidula fornicata. Individuals were collected intertidally from Nahant, Massachusetts from late January to early April each year for 5 years, maintained in the laboratory at the acclimation temperature of 6 °C, and exposed in the laboratory for 3 h to temperatures as high as 37 °C in seawater either once or twice, 24 h apart. Although mean clearance rates were substantially reduced for at least the next 12-24 h after individuals were returned to the 6 °C control condition following exposures to elevated temperatures as low as 21-26 °C, we saw little mortality even following two 3 h exposures to 35 °C, or single exposures to 37 °C. Mortality was substantial, however, in one experiment following a double exposure to 37 °C. Smaller individuals (~5-12 mm in shell length) were somewhat more sensitive to the thermal stress than adults were. Intertidal members of C. fornicata in Massachusetts seem well-prepared to deal with the increasing range of winter air temperatures associated with the global climate confusion predicted for future years. Additional studies will be required to understand the physiological and biochemical mechanisms used by winter-acclimated individuals of this species to tolerate such periodic substantial temperature increases of 29-31 °C.


Assuntos
Gastrópodes , Aclimatação , Animais , Temperatura Alta , Humanos , Estações do Ano , Temperatura
13.
Nat Commun ; 11(1): 5155, 2020 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-33056995

RESUMO

The diverse physiological functions of tocotrienols have listed them as valuable supplementations to α-tocopherol-dominated Vitamin E products. To make tocotrienols more readily available, tocotrienols-producing S. cerevisiae has been constructed by combining the heterologous genes from photosynthetic organisms with the endogenous shikimate pathway and mevalonate pathway. After identification and elimination of metabolic bottlenecks and enhancement of precursors supply, the engineered yeast can produce tocotrienols at yield of up to 7.6 mg/g dry cell weight (DCW). In particular, proper truncation of the N-terminal transit peptide from the plant-sourced enzymes is crucial. To further solve the conflict between cell growth and tocotrienols accumulation so as to enable high-density fermentation, a cold-shock-triggered temperature control system is designed for efficient control of two-stage fermentation, leading to production of 320 mg/L tocotrienols. The success in high-density fermentation of tocotrienols by engineered yeast sheds light on the potential of fermentative production of vitamin E tocochromanols.


Assuntos
Fermentação/fisiologia , Microbiologia Industrial/métodos , Engenharia Metabólica , Saccharomyces cerevisiae/metabolismo , Tocotrienóis/metabolismo , Aclimatação/genética , Vias Biossintéticas/genética , Temperatura Baixa/efeitos adversos , Resposta ao Choque Frio/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação Fúngica da Expressão Gênica , Mutação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
14.
Nat Commun ; 11(1): 4897, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32994415

RESUMO

Soil microbial respiration is an important source of uncertainty in projecting future climate and carbon (C) cycle feedbacks. However, its feedbacks to climate warming and underlying microbial mechanisms are still poorly understood. Here we show that the temperature sensitivity of soil microbial respiration (Q10) in a temperate grassland ecosystem persistently decreases by 12.0 ± 3.7% across 7 years of warming. Also, the shifts of microbial communities play critical roles in regulating thermal adaptation of soil respiration. Incorporating microbial functional gene abundance data into a microbially-enabled ecosystem model significantly improves the modeling performance of soil microbial respiration by 5-19%, and reduces model parametric uncertainty by 55-71%. In addition, modeling analyses show that the microbial thermal adaptation can lead to considerably less heterotrophic respiration (11.6 ± 7.5%), and hence less soil C loss. If such microbially mediated dampening effects occur generally across different spatial and temporal scales, the potential positive feedback of soil microbial respiration in response to climate warming may be less than previously predicted.


Assuntos
Carbono/análise , Metagenoma/genética , Microbiota/fisiologia , Microbiologia do Solo , Solo/química , Aclimatação/genética , Archaea/genética , Archaea/isolamento & purificação , Archaea/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Carbono/metabolismo , Ciclo do Carbono , Celulose/metabolismo , DNA Ambiental/genética , DNA Ambiental/isolamento & purificação , Fungos/genética , Fungos/isolamento & purificação , Fungos/metabolismo , Aquecimento Global , Pradaria , Temperatura Alta/efeitos adversos , Metagenômica , Modelos Genéticos , Raízes de Plantas/química , Poaceae/química
15.
PLoS One ; 15(8): e0236186, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866164

RESUMO

AIM: To establish a gene co-expression network for identifying principal modules and hub genes that are associated with drought resistance mechanisms, analyzing their mechanisms, and exploring candidate genes. METHODS AND FINDINGS: 42 data sets including PRJNA380841 and PRJNA369686 were used to construct the co-expression network through weighted gene co-expression network analysis (WGCNA). A total of 1,896,897,901 (284.30 Gb) clean reads and 35,021 differentially expressed genes (DEGs) were obtained from 42 samples. Functional enrichment analysis indicated that photosynthesis, DNA replication, glycolysis/gluconeogenesis, starch and sucrose metabolism, arginine and proline metabolism, and cell cycle were significantly influenced by drought stress. Furthermore, the DEGs with similar expression patterns, detected by K-means clustering, were grouped into 29 clusters. Genes involved in the modules, such as dark turquoise, yellow, and brown, were found to be appreciably linked with drought resistance. Twelve central, greatly correlated genes in stage-specific modules were subsequently confirmed and validated at the transcription levels, including TraesCS7D01G417600.1 (PP2C), TraesCS5B01G565300.1 (ERF), TraesCS4A01G068200.1 (HSP), TraesCS2D01G033200.1 (HSP90), TraesCS6B01G425300.1 (RBD), TraesCS7A01G499200.1 (P450), TraesCS4A01G118400.1 (MYB), TraesCS2B01G415500.1 (STK), TraesCS1A01G129300.1 (MYB), TraesCS2D01G326900.1 (ALDH), TraesCS3D01G227400.1 (WRKY), and TraesCS3B01G144800.1 (GT). CONCLUSIONS: Analyzing the response of wheat to drought stress during different growth stages, we have detected three modules and 12 hub genes that are associated with drought resistance mechanisms, and five of those genes are newly identified for drought resistance. The references provided by these modules will promote the understanding of the drought-resistance mechanism. In addition, the candidate genes can be used as a basis of transgenic or molecular marker-assisted selection for improving the drought resistance and increasing the yields of wheat.


Assuntos
Aclimatação/genética , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Estresse Fisiológico/genética , Triticum/genética , China , Análise por Conglomerados , Conjuntos de Dados como Assunto , Secas , Perfilação da Expressão Gênica , Genes de Plantas , Melhoramento Vegetal/métodos , RNA-Seq , Seleção Genética
16.
Mar Environ Res ; 160: 105048, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32907741

RESUMO

The thermal response of the amphipod Sunamphitoe parmerong was contrasted between unacclimated 'wild' and acclimated populations. Brooding females were allocated to 17 °C or 23 °C treatments and their progeny developed to adulthood at the same temperature. Tolerance to acute thermal challenge (26-36 °C) was determined. The 17 °C and 23 °C acclimated S. parmerong had a 0.45 and 0.64 risk of death compared to the unacclimated individuals. The upper lethal temperature (LT50) was 27.4 °C for the unacclimated group and 29.6 °C and 30.4 °C for the 17 °C and 23 °C acclimated groups, respectively. Acclimation shifted their LT50 by 2.2 °C and 3 °C, respectively. The wild population exhibited high variability in thermal tolerance, potentially due to their environmental history and greater diversity of genotypes. After acclimation S. parmerong had decreased variability in thermal tolerance and that of the 23 °C group shifted by 1 °C compared with the 17 °C group. These results indicate developmental phenotypic plasticity or differential survival of resilient progeny as potential mechanisms to facilitate persistence in a warming ocean.


Assuntos
Aclimatação , Adaptação Fisiológica , Anfípodes , Aquecimento Global , Anfípodes/fisiologia , Animais , Feminino , Temperatura
17.
Aquat Toxicol ; 228: 105617, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32942115

RESUMO

In fish, the study of cholinesterases (ChEs) and carboxylesterases (CEs), apart from their involvement in neural activity and xenobiotic metabolism, respectively, requires to be further explored. The European sea bass (Dicentrarchus labrax) was the fish model used to characterise B-esterases in several matrices and organs, as well as to assess the impacts of the insecticide fipronil at two temperatures: the natural temperature at the time of sampling (13 °C) and at 16 °C (based on climate change-related predictions for the Mediterranean region). Fipronil exerts harmful effects in non-target species; however, some countries are reluctant to implement regulations without additional evidence on their toxicity. A comprehensive study was performed in fish pre-acclimated to the two targeted temperatures for 15 days. B-esterases were evaluated in multiple samples after 7 and 14 day exposures to fipronil in feed (dose of 10 mg/kg) and after a 7-day depurative period. Based on hydrolysis rates, results showed that CEs were measurable in all matrices while ChEs were more abundant in muscle and, particularly, acetylcholinesterase (AChE) in the brain. A + 3 °C increase in temperature had little influence on B-esterase activity; however, fipronil caused a significant increase in brain AChE (1.5-fold) and CE (3-fold) activities. Other matrices and organs also experienced alterations in their B-esterase activities that could compromise their physiological functions.


Assuntos
Aclimatação/efeitos dos fármacos , Bass/metabolismo , Carboxilesterase/metabolismo , Inseticidas/toxicidade , Pirazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Acetilcolinesterase/metabolismo , Animais , Bass/fisiologia , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Temperatura
18.
Mar Environ Res ; 161: 105123, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32882589

RESUMO

Climate warming is altering the distribution of species, producing range shifts and promoting local extinctions. There is an urgent need to understand the underlying mechanisms that influence the persistence of populations across a species' distribution range in the face of global warming. Ocenebra erinaceus is a marine gastropod that exhibits high intraspecific variability in maternal investment and physiological capacity during early stages, which suggests local adaptation to natal environmental conditions. In this study, reproductive traits and trans-generational adaptation were measured in two subtidal populations: one from the middle (the Solent, UK) and another towards the southern end of their geographic distribution (Arcachon, France). Local adaptation was evaluated with a transfer experiment (i.e. Arcachon females transferred to Solent thermal conditions) and trans-generational adaptation was evaluated in the thermal tolerance response of embryos exposed to temperatures between 10 and 20 °C. This study shows that both populations have similar fitness; however, there are adaptive costs to live under their natal location, resulting in trade-offs between reproductive traits. Transferred females show lower reproductive output, which suggests that females are maladapted to live under a new environment. The trans-generational experiment demonstrates contrasting thermal tolerance ranges between populations. Adaptation to local thermal conditions was observed in transferred embryos, showing poor performance and high mortalities under the new environment. Our results provide a better understanding of intraspecific differences and adaptations across a species' distribution range and provide insights into how climate warming will impact encapsulated species exhibiting location-specific adaptation.


Assuntos
Aclimatação , Adaptação Fisiológica , Animais , Feminino , França , Aquecimento Global , Fenótipo
19.
PLoS One ; 15(9): e0239097, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32925956

RESUMO

The eucheumatoids Kappaphycus and Eucheuma are cultivated in tropical or subtropical regions for the production of carrageenan, a hydrocolloid widely used in the food and cosmetic industries. Kappaphycus alvarezii is a highly valued economic crop in the Coral Triangle, with the Philippines, Indonesia and Malaysia ranked among the largest producers. In the absence of measures to mitigate climate change, extreme events including heatwaves, typhoons, severe El Niño and La Niña, are expected to increase in frequency and magnitude. This inadvertently brings adverse effects to the seaweed cultivation industry, especially in the tropics. Temperatures are rapidly reaching the upper limit of biologically tolerable levels and an increase in reports of ice-ice and pest outbreaks is attributable to these shifts of environmental parameters. Nevertheless, few reports on the response of eucheumatoids to a changing environment, in particular global warming, are available. Understanding the responses and possible mechanisms for acclimation to warming is crucial for a sustainable seaweed cultivation industry. Here, the physiological and biochemical responses of K. alvarezii to acute warming indicated that the strain used in the current study is unlikely to survive sudden increases in temperature above 36°C. As temperature increased, the growth rates, photosynthetic performance, phycocolloid quality (carrageenan yield, gel strength and gel viscosity) and pigment content (chlorophyll-a, carotenoid and phycobiliproteins) were reduced while the production of reactive oxygen species increased indicating the occurrence of stress in the seaweeds. This study provides a basis for future work on long term acclimation to elevated temperature and mesocosm-based multivariate studies to identify heat-tolerant strains for sustainable cultivation.


Assuntos
Aquecimento Global , Rodófitas/fisiologia , Aclimatação , Carragenina/análise , Carragenina/metabolismo , Mudança Climática , Fotossíntese , Pigmentos Biológicos/análise , Pigmentos Biológicos/metabolismo , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismo , Rodófitas/química , Rodófitas/crescimento & desenvolvimento , Temperatura
20.
PLoS One ; 15(9): e0238982, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32931518

RESUMO

Over the past decade, pastoralists in Kunene Region, Namibia, have endured recurrent drought and flood events that have culminated in the loss of their primary form of livelihood-pastoralism. Most pastoralists are finding it difficult to sustain their livelihoods, and their communities have fallen into extreme poverty. Ecosystem-based Adaptation (EbA) approaches are increasingly acknowledged as having the potential to enhance the adaptive capacity of vulnerable communities. The first step is to develop an understanding of how affected communities live, their perceptions of and how they respond to climate change and the biophysical impacts of climate change in their communities. This study aims to collect this information in order to explore the use of EbA to help pastoralists adapt to climate change. We examined an isolated pastoral Himba community, to understand their perceptions, experiences and understanding of climate change and its related impacts on their livelihoods. A nested mixed-methods approach using structured interviews was employed to address the study objectives. Interview results revealed that pastoralists lack scientific knowledge of climate change, and they have no access to climate change information. Though pastoralists have coping and adaptation approaches at the community level (such as making gardens, fishing, etc.), these have become ineffective as climatic uncertainty and change persist. Furthermore, pastoralists no longer get benefits from the environment, such as food and fodder. Despite this, there are currently no biodiversity interventions at the community level to address the impacts of climate change. Pastoralists have indicated their adaptation needs, particularly the provision of water supply to grow food. This is an open avenue to explore EbA approaches, specifically ecological restoration, while still addressing the need of the pastoralists. There is an urgent need to develop new practical adaptation strategies, including restoration options that will strengthen their adaptive capacity.


Assuntos
Criação de Animais Domésticos/métodos , Criação de Animais Domésticos/tendências , Aclimatação , Biodiversidade , Mudança Climática , Conservação dos Recursos Naturais/métodos , Secas , Ecossistema , Inundações , Humanos , Conhecimento , Namíbia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA