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1.
Oecologia ; 205(1): 191-201, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38782789

RESUMO

The transmission of resistance traits to herbivores across subsequent generations is an important strategy employed by plants to enhance their fitness in environments with high herbivore pressure. However, our understanding of the impact of maternal herbivory on direct and indirect induced chemical defenses of progeny, as well as the associated costs, is currently limited to herbivory by leaf-chewing insects. In this study, we investigated the transgenerational effects of a sap-feeding insect, the green peach aphid Myzus persicae, on direct and indirect chemical defenses of bell pepper plants (Capsicum annuum), and whether the effects entail costs to plant growth. Aphid herbivory on parental plants led to a reduced number of seeds per fruit, which exhibited lower germination rates and produced smaller seedlings compared to those from non-infested parental plants. In contrast, the progeny of aphid-infested plants were less preferred as hosts by aphids and less suitable than the progeny of non-infested plants. This enhanced resistance in the progeny of aphid-infested plants coincided with elevated levels of both constitutive and herbivore-induced total phenolic compounds, compared to the progeny of non-infested plants. Furthermore, the progeny of aphid-infested plants emitted herbivore-induced plant volatiles (HIPVs) that were more attractive to the aphid parasitoid Aphidius platensis than those emitted by the progeny of non-infested plants. Our results indicate that herbivory by sap-feeding insect induces transgenerational resistance on progeny bell pepper plants, albeit at the expense of vegetative growth.


Assuntos
Afídeos , Capsicum , Herbivoria , Animais , Afídeos/fisiologia , Defesa das Plantas contra Herbivoria
2.
Materials (Basel) ; 17(3)2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38591660

RESUMO

Self-healing cementitious materials containing microcapsules filled with healing agents can autonomously seal cracks and restore structural integrity. However, optimising the microcapsule mechanical properties to survive concrete mixing whilst still rupturing at the cracked interface to release the healing agent remains challenging. This study develops an integrated numerical modelling and machine learning approach for tailoring acrylate-based microcapsules for triggering within cementitious matrices. Microfluidics is first utilised to produce microcapsules with systematically varied shell thickness, strength, and cement compatibility. The capsules are characterised and simulated using a continuum damage mechanics model that is able to simulate cracking. A parametric study investigates the key microcapsule and interfacial properties governing shell rupture versus matrix failure. The simulation results are used to train an artificial neural network to rapidly predict the triggering behaviour based on capsule properties. The machine learning model produces design curves relating the microcapsule strength, toughness, and interfacial bond to its propensity for fracture. By combining advanced simulations and data science, the framework connects tailored microcapsule properties to their intended performance in complex cementitious environments for more robust self-healing concrete systems.

5.
Materials (Basel) ; 15(14)2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35888417

RESUMO

Intelligent cementitious materials integrated with carbon nanofibers (CNFs) have the potential to be used as sensors in structural health monitoring (SHM). The difficulty in dispersing CNFs in cement-based matrices, however, limits the sensitivity to deformation (gauge factor) and strength. Here, we synthesise CNF by chemical vapour deposition on the surface of calcium oxide (CaO) and, for the first time, investigate this amphiphilic carbon nanomaterial for self-sensing in mortar. SEM, TEM, TGA, Raman and VSM were used to characterise the produced CNF@CaO. In addition, the electrical resistivity of the mortar, containing different concentrations of CNF with and without CaO, was measured using the four-point probe method. Furthermore, the piezoresistive response of the composite was quantified by means of compressive loading. The synthesised CNF was 5-10 µm long with an average diameter of ~160 nm, containing magnetic nanoparticles inside. Thermal decomposition of the CNF@CaO compound indicated that 26% of the material was composed of CNF; after CaO removal, 84% of the material was composed of CNF. The electrical resistivity of the material drops sharply at concentrations of 2% by weight of CNF and this drop is even more pronounced for samples with 1.2% by weight of washed CaO. This indicates a better dispersion of the material when the CaO is removed. The sensitivity to deformation of the sample with 1.2% by weight of CNF@CaO was quantified as a gauge factor (GF) of 1552, while all other samples showed a GF below 100. Its FCR amplitude can vary inversely up to 8% by means of cyclic compressive loading. The method proposed in this study provides versatility for the fabrication of carbon nanofibers on a tailored substrate to promote self-sensing in cementitious materials.

6.
Life Sci ; 305: 120758, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-35798071

RESUMO

AIMS: To investigate the effects of endurance training on stress-induced cardiometabolic perturbations given the elevated release of stress hormones and subsequent glucose homeostasis perturbations. MATERIALS AND METHODS: Rats were randomized into non-trained rats, rats submitted to endurance training, non-trained rats submitted to stress, and trained rats submitted to stress. Endurance training was applied for 8 weeks, while chronic stress was applied at the 4th, 5th, and 6th weeks of the training period. Two weeks after the last stressor stimuli, rats were euthanized, and blood and heart were collected for biochemical tests. KEY FINDINGS: Exacerbated corticosterone levels were observed in both stressed groups, and chronic stress per se impaired glucose tolerance and insulin sensitivity. Training reduced circulating adrenaline, even though noradrenaline levels were elevated in the blood and heart of trained rats. While stress-induced high circulating serotonin levels were further increased by endurance training, cardiac serotonin levels were attenuated in trained rats. Endurance training mitigated the stress-induced higher circulating lipids. Cardiac TBARs and GPx activity increased in trained rats while CAT and GPx were reduced in response to chronic stress. Endurance training not only attenuated the stress-induced higher circulating ACE/ACE2 ratio but also reduced ACE/ACE2 balance in the heart. Glucose intolerance, insulin resistance, and altered stress hormones release were linked to impairment of cardiometabolic responses, elevated oxidative stress, and dysregulation of ACE/ACE2 ratio. SIGNIFICANCE: Endurance training mitigated the stress-related pathophysiological responses, which could be related to improvements in the antioxidant capacity and the balance of ACE/ACE2 activity.


Assuntos
Doenças Cardiovasculares , Treino Aeróbico , Enzima de Conversão de Angiotensina 2 , Animais , Hormônios , Humanos , Estresse Oxidativo , Peptidil Dipeptidase A/metabolismo , Ratos , Serotonina
7.
Life Sci ; 301: 120616, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35533758

RESUMO

AIMS: We aimed to investigate whether Saccharomyces boulardii strain might exert renoprotective effects by modulating renal renin angiotensin system, oxidative stress and intestinal microbiota in streptozotocin-diabetic mice. MAIN METHODS: Thirty-six C57BL/6 male mice were divided into four groups: control (C), control + probiotic (CP), diabetes (D), diabetes + probiotic (DP). Diabetes was induced by one intraperitoneal injection of streptozotocin and Saccharomyces boulardii was administered by oral gavage for 8 weeks. Blood glucose, albuminuria and urinary volume were measured. Renal levels of angiotensin peptides (angiotensin I, II and 1-7) and the activities of angiotensin-converting enzyme (ACE) and ACE2 were determined, besides that, renal morphology, serotonin and dopamine levels and also microbiota composition were analyzed. KEY FINDINGS: Probiotics significantly increased C-peptide secretion and reduced blood glucose of diabetic animals. Saccharomyces boulardii also improved renal antioxidant defense, restored serotonin and dopamine concentration, and activated the renin-angiotensin system (RAS) vasodilator and antifibrotic axis. The modulation of these markers was associated with a beneficial impact on glomerular structure and renal function of diabetic treated animals. The phenotypic changes induced by Saccharomyces boulardii were also related to modulation of intestinal microbiota, evidenced by the decreased abundance of Proteus and Escherichia-Shigella, considered diabetic nephropathy biomarkers. SIGNIFICANCE: Therefore, probiotic administration to streptozotocin-induced diabetic mice improves kidney structure and function in a murine model and might represent a reasonable strategy to counteract nephropathy-associated maladaptive responses in diabetes.


Assuntos
Diabetes Mellitus Experimental , Nefropatias Diabéticas , Microbiota , Saccharomyces boulardii , Angiotensina I/metabolismo , Animais , Glicemia/metabolismo , Diabetes Mellitus Experimental/metabolismo , Nefropatias Diabéticas/metabolismo , Modelos Animais de Doenças , Dopamina/metabolismo , Rim/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Estresse Oxidativo , Sistema Renina-Angiotensina/fisiologia , Saccharomyces boulardii/metabolismo , Serotonina/metabolismo , Estreptozocina/metabolismo
8.
Life Sci ; 298: 120517, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35367239

RESUMO

AIMS: To investigate whether a specific endothelium-derived microparticles (EMPs) phenotype could be associated with birth weight and microvascular endothelial function in children. MATERIALS AND METHODS: A total of 95 children aged 6-14 years were recruited. Anthropometric measurements, blood pressure measurement, microvascular endothelial function testing, and biochemical profile analyses were performed. Standardized flow cytometry methods were used to identify and quantify the circulating CD144+, CD31+/annexin V+, and CD62E+ EMPs. KEY FINDINGS: The circulating number of CD31+/annexin V+ EMPs and CD144+ EMP levels were correlated with birth weight, systolic blood pressure, microvascular endothelial function, total cholesterol, and low-density lipoprotein cholesterol (LDL-C) level. In the multivariable logistic regression models, we identified strong evidence of a higher risk of microvascular endothelial dysfunction among children with low birth weight (LBW) and increased levels of both CD31+/annexin V+ EMPs and LDL-C; LBW and elevated LDL-C levels were independent predictors of high circulating numbers of CD31+/annexin V+ and CD144+ > 75th percentile EMPs. SIGNIFICANCE: Our data provide evidence that children with LBW values showed greater numbers of circulating CD31+/annexin V+ and CD144+ EMPs. In addition, LBW and high levels of CD31+/annexin V+ and LDL-C were significant risk factors for the presence of microvascular endothelial dysfunction.


Assuntos
Micropartículas Derivadas de Células , Anexina A5 , Peso ao Nascer , LDL-Colesterol , Endotélio Vascular , Humanos
9.
Obes Res Clin Pract ; 16(2): 115-121, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35177373

RESUMO

BACKGROUND: Obesity perturbs endothelium integrity, leading to endothelial activation, which predisposes the release of endothelium-derived microparticles (EMP). We measured the CD31+/annexin V+ and CD62E+ EMP levels to improve our understanding of their contribution to endothelial damage in children with overweight/obesity. SUBJECT AND METHODS: In this cross-sectional study, 107 children with normal weight and 35 children with overweight/obesity were evaluated. Anthropometric measurement, blood pressure, biochemical profile was performed. Standardized flow cytometry methods were used to identify and quantify circulating CD31+/annexin V+ and CD62E+ EMP. RESULTS: Children with overweight/obesity had significantly higher circulating levels of CD31+/annexin V+ (750 [600]) and CD62E+ (1400 [700]) EMP than those with normal weight (P < 0.001 for both). We found that EMP levels were positively correlated with body mass index (BMI), waist circumference, blood pressure, total cholesterol, low-density lipoprotein cholesterol (LDLc), and triglycerides. The multivariable logistic regression model revealed that the risks of having high EMP levels (> 75th percentile) were high in children with both large waist circumference and elevated LDLc level. Receiver operating characteristic (ROC) curves demonstrated that the LDLc levels showed significantly greater discrimination than waist circumference for both CD31+/annexin V+ (P = 0.031) as CD62E+ EMPs (P = 0.041). CONCLUSIONS: Children with overweight/obesity have high circulating CD31+/annexin V+ and CD62E+ EMP levels, which may be an early sign of endothelial apoptosis and inflammatory activation in response to injury. These EMP levels were positively associated with several cardiometabolic risk factors. Our data underscore the negative influence of high-risk metabolic profiles on endothelial integrity in the early stages of childhood obesity.


Assuntos
Sobrepeso , Obesidade Infantil , Anexina A5/metabolismo , Criança , LDL-Colesterol , Estudos Transversais , Endotélio Vascular , Humanos , Sobrepeso/complicações , Sobrepeso/metabolismo , Obesidade Infantil/complicações
10.
Am J Hum Biol ; 34(1): e23595, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-33709521

RESUMO

BACKGROUND: There is increasing evidence that low birth weight has a negative effect on physical fitness, muscle strength, and cardiorespiratory endurance, although the findings are inconsistent. OBJECTIVES: This study aimed to evaluate whether birth weight acts as a prenatal determinant of physical fitness parameters and to determine the role of environmental or biological variables on this effect. METHODS: One hundred and sixty-seven children aged 6-14 years were included in this study. The anthropometric data, physical activity index, standing long jump, flexibility, handgrip strength, and cardiorespiratory fitness were evaluated. RESULTS: A positive correlation was found between birth weight and cardiorespiratory fitness (r = .349; p < .001), right handgrip strength (r = .337; p < .001), and left handgrip strength (r = .320; p < .001), suggesting that children with low birth weight had the worst performance in both cardiorespiratory endurance and grip strength tests. These findings remained significant after adjustment for prematurity, sex, age, physical activity index, and body mass index (BMI). Stepwise multiple regression analyses revealed a significant interaction of high birth weight, older age, and low BMI in predicting better cardiorespiratory endurance (R2  = .308). When handgrip strength was tested as the dependent variable, we found that high birth weight, male sex, and older age emerged as important determinants for both sides. CONCLUSION: Children aged 6-14 years born with a birth weight < 2.5 kg have low handgrip strength and cardiorespiratory fitness, which seems to be mediated partially by influences of both prenatal environment (e.g., birth weight) and biological variables (e.g., age, sex, BMI).


Assuntos
Aptidão Cardiorrespiratória , Força da Mão , Idoso , Índice de Massa Corporal , Criança , Feminino , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Masculino , Força Muscular , Resistência Física , Aptidão Física , Gravidez
11.
Lab Chip ; 21(23): 4652-4659, 2021 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-34734612

RESUMO

Capsule-based self-healing of cementitious materials is an effective way of healing cracks, significantly extending the life of structures, without imposing changes due to the incorporation of capsules into products during mixing. The methodologies currently being used for the development of capsules with a liquid core as a healing agent yield a wide range of sizes and shell thicknesses for the microcapsules, preventing a detailed assessment and optimisation of the microcapsule size and its effects. Uniquely, microfluidic technology offers precise control over the size and shell thickness through the formation of double emulsions. The drawback is that only small quantities of material can be typically produced. Here, by using paralleled junctions in a microfluidic device, high throughput production of materials was achieved, focusing for the first time on self-healing of cementitious materials. A microfluidic chip was assembled with 4 channels in parallel and selected hydrophobicity for the formation of the double emulsions. A coefficient of variation below 2.5% was observed for the 4 junctions, demonstrating the formation of monodisperse capsules. The control over the size and shell thickness by adjusting the flow rates was demonstrated, yielding capsules with an outer diameter of 615-630 µm and a shell thickness varying between 50 and 127 µm. By using triethanolamine as a surfactant, capsules with an aqueous core were produced. Furthermore, by selecting PEA, an acrylate with low tensile strength, the capsules embedded in the cement paste were successfully triggered to release the healing agent by crack formation. Capsules were successfully produced continuously for 7 h, with inner and outer diameters of 500 ± 31 µm and 656 ± 9 µm at a production rate of ∼13 g h-1 and a yield of around 80%. With these results and considering up to 6 chips in parallel, the production rate could be up to 1.5 kg per day. This demonstrates the huge potential of the microfluidic device with unique features to produce sufficiently large quantities of microcapsules for laboratory-scale assessment of self-healing performance.


Assuntos
Microfluídica , Água , Cápsulas , Emulsões
12.
J Therm Biol ; 99: 103010, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34420640

RESUMO

Irisin is an adipomyokine that increases browning of adipose tissue and thermogenesis, thereby protecting against obesity and insulin resistance. However, the correlation between irisin, brown adipose tissue (BAT), and childhood obesity, as well as its association with an increased risk of developing metabolic diseases, has not been completely elucidated. This study aimed to investigate the association between irisin levels and BAT activity measured by infrared thermography among children and verify their correlation with anthropometric and metabolic parameters. This study included 42 children with normal weight and 18 overweight/obese children. Anthropometric data, irisin levels, lipid and glucose profile were evaluated. The percentage of the thermally active portion of the supraclavicular area (%AreaSCR) before and after a cold stimulus was measured by infrared thermography, and the differences between the percentages of thermally active (Δ%AreaSCR) was calculated as an index of BAT activation. The results were correlated with anthropometric and metabolic parameters. Circulating irisin levels was positive correlated with age (rho=0.327, P= 0.011), body mass index (BMI) (rho=0.707, P<0.001), waist circumference (rho=0.624, P<0.001), total cholesterol (rho=0.361, P=0.044), triglycerides (rho=0.419, P=0.001), and low-density lipoprotein cholesterol (LDLc) (rho=0.381, P= 0.003). Active BAT was negatively correlated with BMI, waist circumference, triglycerides, LDLc and irisin levels. We observed that normal weight children increased significantly the Δ% AreaSCR as compared to overweight/obese children. In conclusion, circulating irisin levels and BAT activity appear to have opposing roles, since normal weight children had greater BAT activity and lower circulating levels of irisin.


Assuntos
Tecido Adiposo Marrom/metabolismo , Fibronectinas/metabolismo , Obesidade Infantil/metabolismo , Criança , Feminino , Fibronectinas/sangue , Humanos , Masculino , Metaboloma , Obesidade Infantil/sangue , Termografia
13.
Materials (Basel) ; 13(24)2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33353221

RESUMO

Soil mix cut-off walls have been increasingly used for containment of organic contaminants in polluted land. However, the mixed soil is susceptible to deterioration due to aggressive environmental and mechanical stresses, leading to crack-originated damage and requiring costly maintenance. This paper proposed a novel approach to achieve self-healing properties of soil mix cut-off wall materials triggered by the ingress of organic contaminants. Oil sorbent polymers with high absorption and swelling capacities were incorporated in a cementitious grout and mixed with soil using a laboratory-scale auger setup. The self-healing performance results showed that 500 µm-wide cracks could be bridged and blocked by the swollen oil sorbents, and that the permeability was reduced by almost an order of magnitude after the permeation of liquid paraffin. It was shown by micro-CT scan tests that the network formed by the swollen oil sorbents acted as attachments and binder, preventing the cracked mixed soil sample from crumbling, and that the oil sorbents swelled three times in volume and therefore occupied the air space and blocked the cracks in the matrix. These promising results exhibit the potential for the oil sorbents to provide soil mix cut-off walls in organically-contaminated land with self-healing properties and enhanced durability.

15.
PLoS One ; 15(10): e0240665, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33057449

RESUMO

The management of germplasm banks is complex, especially when many accessions are involved. Microsatellite markers are an efficient tool for assessing the genetic diversity of germplasm collections, optimizing their use in breeding programs. This study genetically characterizes a large collection of 410 grapevine accessions maintained at the Agronomic Institute of Campinas (IAC) (Brazil). The accessions were genotyped with 17 highly polymorphic microsatellite markers. Genetic data were analyzed to determine the genetic structure of the germplasm, quantify its allelic diversity, suggest the composition of a core collection, and discover cases of synonymy, duplication, and misnaming. A total of 304 alleles were obtained, and 334 unique genotypes were identified. The molecular profiles of 145 accessions were confirmed according to the literature and databases, and the molecular profiles of more than 100 genotypes were reported for the first time. The analysis of the genetic structure revealed different levels of stratification. The primary division was between accessions related to Vitis vinifera and V. labrusca, followed by their separation from wild grapevine. A core collection of 120 genotypes captured 100% of all detected alleles. The accessions selected for the core collection may be used in future phenotyping efforts, in genome association studies, and for conservation purposes. Genetic divergence among accessions has practical applications in grape breeding programs, as the choice of relatively divergent parents will maximize the frequency of progeny with superior characteristics. Together, our results can enhance the management of grapevine germplasm and guide the efficient exploitation of genetic diversity to facilitate the development of new grape cultivars for fresh fruits, wine, and rootstock.


Assuntos
Variação Genética , Melhoramento Vegetal , Banco de Sementes , Vitis/genética , Algoritmos , Alelos , Brasil , Ecótipo , Repetições de Microssatélites/genética , Filogenia , Reprodutibilidade dos Testes
16.
Anat Histol Embryol ; 48(3): 264-267, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30772943

RESUMO

The vertebral heart score or size (VHS) measurement is routinely used to provide a more objective measurement of cardiomegaly in dogs. However, breed or body conformation can influence the VHS. To assess the specific VHS for the Australian Cattle Dog, left-to-right lateral, right-to-left lateral, dorsoventral and ventrodorsal thoracic radiographs from 20 individuals free from cardiac and pulmonary disease were obtained. The mean VHS was significantly higher in Australian Cattle Dog (10.5 ± 0.4 vertebrae), when compared with the average VHS for 100 normal dogs of different breeds that had been initially published (9.7 ± 0.5 vertebrae). This emphasizes the importance of breed-specific VHS ranges. In our study group of normal Australian Cattle Dogs, the mean VHS was 10.5 ± 0.5 vertebrae (mean ±SD) on right lateral and 10.3 ± 0.5 vertebrae on left lateral radiographs. The VHS on right lateral views was significantly larger than on left lateral views. The VHS was 10.5 ± 0.6 vertebrae on dorsoventral and 11.1 ± 0.6 vertebrae on ventrodorsal radiographs. The VHS on ventrodorsal views was significantly larger than on dorsoventral views.


Assuntos
Cães/anatomia & histologia , Coração/anatomia & histologia , Animais , Cães/classificação , Cães/fisiologia , Ecocardiografia/veterinária , Eletrocardiografia/veterinária , Feminino , Coração/diagnóstico por imagem , Auscultação Cardíaca/veterinária , Masculino , Valores de Referência , Restrição Física/veterinária
17.
BMC Plant Biol ; 18(1): 223, 2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30305095

RESUMO

BACKGROUND: Rubber tree is cultivated in mainly Southeast Asia and is by far the most significant source of natural rubber production worldwide. However, the genetic architecture underlying the primary agronomic traits of this crop has not been widely characterized. This study aimed to identify quantitative trait loci (QTLs) associated with growth and latex production using a biparental population established in suboptimal growth conditions in Brazil. RESULTS: A full-sib population composed of 251 individuals was developed from crossing two high-producing Asiatic rubber tree cultivars, PR 255 and PB 217. This mapping population was genotyped with microsatellite markers from enriched genomic libraries or transcriptome datasets and single-nucleotide polymorphism (SNP) markers, leading to construction of a saturated multipoint integrated genetic map containing 354 microsatellite and 151 SNP markers. Height and circumference measurements repeated over a six-year period and registration of cumulative latex production during six consecutive months on the same individuals allowed in-depth characterization of the genetic values of several growth traits and precocious latex production. Growth traits, circumference and height, were overall positively correlated, whereas latex production was not correlated or even negatively correlated with growth traits. A total of 86 distinct QTLs were identified, most of which were detected for only one trait. Among these QTLs, 15 were linked to more than one phenotypic trait (up to 4 traits simultaneously). Latex production and circumference increments during the last wintering period were associated with the highest numbers of identified QTLs (eleven and nine, respectively), jointly explaining the most significantly observed phenotypic variances (44.1% and 44.4%, respectively). The most important QTL for latex production, located on linkage group 16, had an additive effect of the male parent PB 217 and corresponded to a QTL at the same position detected in a previous study carried out in Thailand for the biparental population RRIM 600 x PB 217. CONCLUSIONS: Our results identified a set of significant QTLs for rubber tree, showing that the performance of modern Asiatic cultivars can still be improved and paving the way for further marker-assisted selection, which could accelerate breeding programs.


Assuntos
Hevea/genética , Látex/metabolismo , Locos de Características Quantitativas , Brasil , Clima , Hevea/metabolismo , Repetições de Microssatélites , Fenótipo , Polimorfismo de Nucleotídeo Único
18.
Front Plant Sci ; 9: 1255, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30197655

RESUMO

Rubber tree (Hevea brasiliensis) cultivation is the main source of natural rubber worldwide and has been extended to areas with suboptimal climates and lengthy drought periods; this transition affects growth and latex production. High-density genetic maps with reliable markers support precise mapping of quantitative trait loci (QTL), which can help reveal the complex genome of the species, provide tools to enhance molecular breeding, and shorten the breeding cycle. In this study, QTL mapping of the stem diameter, tree height, and number of whorls was performed for a full-sibling population derived from a GT1 and RRIM701 cross. A total of 225 simple sequence repeats (SSRs) and 186 single-nucleotide polymorphism (SNP) markers were used to construct a base map with 18 linkage groups and to anchor 671 SNPs from genotyping by sequencing (GBS) to produce a very dense linkage map with small intervals between loci. The final map was composed of 1,079 markers, spanned 3,779.7 cM with an average marker density of 3.5 cM, and showed collinearity between markers from previous studies. Significant variation in phenotypic characteristics was found over a 59-month evaluation period with a total of 38 QTLs being identified through a composite interval mapping method. Linkage group 4 showed the greatest number of QTLs (7), with phenotypic explained values varying from 7.67 to 14.07%. Additionally, we estimated segregation patterns, dominance, and additive effects for each QTL. A total of 53 significant effects for stem diameter were observed, and these effects were mostly related to additivity in the GT1 clone. Associating accurate genome assemblies and genetic maps represents a promising strategy for identifying the genetic basis of phenotypic traits in rubber trees. Then, further research can benefit from the QTLs identified herein, providing a better understanding of the key determinant genes associated with growth of Hevea brasiliensis under limiting water conditions.

19.
Front Plant Sci ; 9: 815, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30018620

RESUMO

Among rubber tree species, which belong to the Hevea genus of the Euphorbiaceae family, Hevea brasiliensis (Willd. ex Adr.de Juss.) Muell. Arg. is the main commercial source of natural rubber production worldwide. Knowledge of the population structure and linkage disequilibrium (LD) of this species is essential for the efficient organization and exploitation of genetic resources. Here, we obtained single-nucleotide polymorphisms (SNPs) using a genotyping-by-sequencing (GBS) approach and then employed the SNPs for the following objectives: (i) to identify the positions of SNPs on a genetic map of a segregating mapping population, (ii) to evaluate the population structure of a germplasm collection, and (iii) to detect patterns of LD decay among chromosomes for future genetic association studies in rubber tree. A total of 626 genotypes, including both germplasm accessions (368) and individuals from a genetic mapping population (254), were genotyped. A total of 77,660 and 21,283 SNPs were detected by GBS in the germplasm and mapping populations, respectively. The mapping population, which was previously mapped, was constructed with 1,062 markers, among which only 576 SNPs came from GBS, reducing the average interval between two adjacent markers to 4.4 cM. SNPs from GBS genotyping were used for the analysis of genetic structure and LD estimation in the germplasm accessions. Two groups, which largely corresponded to the cultivated and wild populations, were detected using STRUCTURE and via principal coordinate analysis. LD analysis, also using the mapped SNPs, revealed that non-random associations varied along chromosomes, with regions of high LD interspersed with regions of low LD. Considering the length of the genetic map (4,693 cM) and the mean LD (0.49 for cultivated and 0.02 for wild populations), a large number of evenly spaced SNPs would be needed to perform genome-wide association studies in rubber tree, and the wilder the genotypes used, the more difficult the mapping saturation.

20.
Horm Behav ; 97: 14-17, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28987550

RESUMO

Genetic, social, and environmental conditions contribute to the development of depression, but the pathophysiological mechanisms are still unclear. Data accumulated in recent years provide significant evidence for a direct role of galanin (GAL). This study aimed to investigate the relation between SNPs in the galaninergic system and depressive symptoms in adolescents. A total of112 adolescents aged 10-18years participated in this study. The Children Depression Inventory (CDI) was used to evaluate depressive symptoms. The effects of rs948854 and rs4432027 SNPs, both located within the promoter region of the GAL gene, rs11665337 in the GALR1 receptor, and rs8836 in the GALR2 receptor on depressive symptoms were examined. The results indicated that 30.4% of the participants had depression. We found that girls were significantly more likely to be depressive than boys. Furthermore, rs948854 minor (G) allele was associated with depressive symptoms. Adolescents carrying the GG and AG genotype for the A/G (rs948854) SNP showed higher CDI scores than those carrying homozygous AA. The binomial logistic regression analysis revealed that adolescents carrying the GG genotype at SNP rs948854 had a higher likelihood of being depressive than adolescents carrying the AA or AG genotypes (P=0.033). Moreover, individuals whose mothers had a positive history for depression and who were sedentary were more likely to display depressive symptoms (P=0.013 and P=0.032, respectively). In conclusion, the SNP rs948854 in the GAL gene seems to be involved in the modulation of depressive state, especially in individuals with GG genotype.


Assuntos
Alelos , Depressão/genética , Galanina/genética , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único , Adolescente , Criança , Feminino , Estudos de Associação Genética , Genótipo , Humanos , Masculino , Fatores Sexuais
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