Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Trends Plant Sci ; 29(6): 630-637, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38485646

RESUMO

Dioecious plant species exhibit sexual dimorphism in various aspects, including morphology, physiology, life history, and behavior, potentially influencing sex-specific interactions. While it is generally accepted that intersexual interactions in dioecious species are less intense compared with intrasexual interactions, the mechanisms underlying belowground facilitation in intersexual combinations remain less understood. Here, we explore these mechanisms, which encompass resource complementarity, mycorrhizal fungal networks, root exudate-mediated belowground chemical communication, as well as plant-soil feedback. We address the reason for the lack of consistency in the strength of inter- and intrasexual interactions. We also propose that a comprehensive understanding of the potential positive consequences of sex-specific interactions can contribute to maintaining ecological equilibrium, conserving biodiversity, and enhancing the productivity of agroforestry.


Assuntos
Micorrizas , Micorrizas/fisiologia , Plantas/microbiologia , Raízes de Plantas/fisiologia , Raízes de Plantas/microbiologia , Ecossistema , Fenômenos Fisiológicos Vegetais , Solo
2.
Hum Brain Mapp ; 45(2): e26583, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38339902

RESUMO

Although it has been established that cross-modal activations occur in the occipital cortex during auditory processing among congenitally and early blind listeners, it remains uncertain whether these activations in various occipital regions reflect sensory analysis of specific sound properties, non-perceptual cognitive operations associated with active tasks, or the interplay between sensory analysis and cognitive operations. This fMRI study aimed to investigate cross-modal responses in occipital regions, specifically V5/MT and V1, during passive and active pitch perception by early blind individuals compared to sighted individuals. The data showed that V5/MT was responsive to pitch during passive perception, and its activations increased with task complexity. By contrast, widespread occipital regions, including V1, were only recruited during two active perception tasks, and their activations were also modulated by task complexity. These fMRI results from blind individuals suggest that while V5/MT activations are both stimulus-responsive and task-modulated, activations in other occipital regions, including V1, are dependent on the task, indicating similarities and differences between various visual areas during auditory processing.


Assuntos
Lobo Occipital , Percepção da Altura Sonora , Humanos , Lobo Occipital/diagnóstico por imagem , Percepção da Altura Sonora/fisiologia , Percepção Auditiva/fisiologia , Cegueira/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Mapeamento Encefálico/métodos
3.
Pestic Biochem Physiol ; 194: 105516, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37532331

RESUMO

Helicoverpa armigera is a worldwide pest that has been efficiently controlled by transgenic plants expressing Bt Cry toxins. To exert toxicity, Cry toxins bind to different receptors located in larval midgut cells. Previously, we reported that GATA transcription factor GATAe activates the expression of multiple H. armigera Cry1Ac receptors in different insect cell lines. Here, the mechanism involved in GATAe regulation of HaABCC2 gene expression, a key receptor of Cry1Ac, was analyzed. HaGATAe gene silencing by RNAi in H. armigera larvae confirmed the activation role of HaGATAe on the expression of HaABCC2 in the midgut. The contribution of all potential GATAe-binding sites was analyzed by site-directed mutagenesis using Hi5 cells expressing a reporter gene under regulation of different modified HaABCC2 promoters. DNA pull-down assays revealed that GATAe bound to different predicted GATA-binding sites and mutations of the different GATAe-binding sites identified two binding sites responsible for the promoter activity. The binding site B9, which is located near the transcription initiator site, has a major contribution on HaABCC2 expression. Also, DNA pull-down assays revealed that all other members of GATA TF family in H. armigera, besides GATAe, HaGATAa, HaGATAb, HaGATAc and HaGATAd also bound to the HaABCC2 promoter and decreased the GATAe dependent promoter activity. Finally, the potential participation in the regulation of HaABCC2 promoter of several TFs other than GATA TFs expressed in the midgut cells was analyzed. HaHR3 inhibited the GATAe dependent activity of the HaABCC2 promoter, while two other midgut-related TFs, HaCDX and HaSox21, also bound to the HaABCC2 promoter region and increased the GATAe dependent promoter activity. All these data showed that GATAe induces HaABCC2 expression by binding to HaGATAe binding sites in the promoter region and that additional TFs participate in modulating the HaGATAe-driven expression of HaABCC2.


Assuntos
Helicoverpa armigera , Inseticidas , Fatores de Transcrição GATA , Proteína 2 Associada à Farmacorresistência Múltipla/genética , Animais , Inseticidas/toxicidade
4.
New Phytol ; 240(4): 1519-1533, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37615210

RESUMO

Little is known about how sex differences in root zone characteristics, such as contents of allelochemicals and soil microbial composition, mediate intra- and intersexual interactions in dioecious plants. We examined the processes and mechanisms of sex-specific belowground interactions mediated by allelochemicals and soil microorganisms in Populus cathayana females and males in replicated 30-yr-old experimental stands in situ and in a series of controlled experiments. Female roots released a greater amount and more diverse phenolic allelochemicals into the soil environment, resulting in growth inhibition of the same sex neighbors and deterioration of the community of soil microorganisms. When grown with males, the growth of females was consistently enhanced, especially the root growth. Compared with female monocultures, the presence of males reduced the total phenolic accumulation in the soil, resulting in a shift from allelopathic inhibition to chemical facilitation. This association was enhanced by a favorable soil bacterial community and increased bacterial diversity, and it induced changes in the orientation of female roots. Our study highlighted a novel mechanism that enhances female performance by males through alterations in the allelochemical content and soil microbial composition. The possibility to improve productivity by chemical mediation provides novel opportunities for managing plantations of dioecious plants.


Assuntos
Populus , Animais , Populus/fisiologia , Solo/química , Feromônios , Plantas , Raízes de Plantas
5.
J Gastrointest Oncol ; 14(1): 265-277, 2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36915438

RESUMO

Background: To study the curative effect of sclerotherapy with lauromacrogol on a rabbit VX2 implanted liver tumor model, the effect of ultrasound-guided sclerotherapy with different doses of lauromacrogol in the treatment of the rabbit VX2 implanted liver tumor model and the degree of damage to the surrounding liver tissue was compared and observed. The relationship between the sclerosing effect and drug dose of lauromacrogol in the treatment of liver cancer is preliminarily discussed. Methods: Thirty rabbit models of liver cancer were randomly divided into 5 groups. Control Group A was injected with normal saline, control Group B was injected with absolute ethanol, experimental Group C was injected with lauromacrogol (Z =2.885D); the injection volume in experimental Group D was 1.5-fold higher than that in Group C; and the injection volume in experimental Group E was 2-fold higher than that in Group C. Changes in tumor volume were followed up by ultrasound before and 7 and 14 days after the operation; contrast-enhanced ultrasonography was used to measure the volume of the ablation area and volume rate. For pathological anatomy, hematoxylin and eosin (H&E) staining were used to observe tumor cell necrosis and the degree of damage to surrounding normal liver cells. The expression levels of the apoptosis-related protein cleaved-caspase 3 and the cell proliferation antigen Ki67 were examined by immunohistochemistry. Results: The volumes in Groups A and C increased significantly. The volumes in Groups B, D, and E remained the same or slightly expanded, tumor growth in the three groups was significantly inhibited after sclerotherapy. Contrast-enhanced ultrasonography showed that the ablation volume and ablation volume rate in Groups B, D, and E were similar. Group C were smaller than those in the other treatment groups. Large coagulative necrotic foci were observed in the central area of tumors in Groups B, D, and E. Conclusions: The experiment demonstrates that lauromacrogol can inhibit tumor growth in the rabbit VX2 tumor model and cause VX2 tumor cell apoptosis. The sclerosing effect of the 1.5-fold amount of lauromacrogol is equivalent to that of absolute ethanol, with little effect on normal liver tissue.

6.
Anal Chim Acta ; 1241: 340803, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36657875

RESUMO

Variations of malondialdehyde (MDA) level in biological samples often induce pathological changes, which is associated with various diseases. Here, we developed a combined surface-enhanced Raman spectroscopy (SERS) and colorimetric strategy for MDA quantitation. The methodology is based on the condensation reaction between 4-aminothiophenol (4-ATP)-modified Au nanoflowers (Au NFs) with the aldehyde groups of MDA, which causes the aggregation of the Au NFs and a concomitant change in the solution color from purple to blue and shifts in the local surface plasmon resonance band to longer wavelengths compared with monodisperse NFs. Additionally, after the condensation reaction, a new Raman peak ascribable to the CN vibration appeared at 1630 cm-1. The intensity of this peak was directly related to the concentration of MDA in solution, which allowed establishing the quantitative measurement of MDA based on SERS. The developed SERS assay displayed satisfactory sensitivity and selectivity with a broad linear range from 1.0 × 10-12 to 1.0 × 10-7 M and a low detection limit (∼3.6 × 10-13 M), outperforming other reported optical and electrochemical methods. Furthermore, the use of 4-ATP-modified Au NF probes to monitor MDA in human serum demonstrates the applicability of this combined SERS/colorimetric approach in a real environment.


Assuntos
Nanopartículas Metálicas , Análise Espectral Raman , Humanos , Análise Espectral Raman/métodos , Colorimetria , Malondialdeído , Nanopartículas Metálicas/química , Ouro/química , Trifosfato de Adenosina
7.
Environ Pollut ; 313: 120123, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36087893

RESUMO

Dioecious plants show sexual differences in resistance traits to abiotic stresses. However, the effects of exogenous pesticide application on female and male plant growth and their associated adaptation mechanisms are unclear. Our study investigated the effects of the broad-spectrum pesticide lambda-cyhalothrin (λ-CY) on dioecious Populus cathayana growth and explored the factors through which λ-CY changed the rhizosphere bacterial community and physicochemical soil properties via sex-specific metabolomics. The sequential application of λ-CY significantly suppressed male shoot- and root biomass, with little effect on the growth of females. Females possessed a higher intrinsic chemo-diversity within their root exudates, and their levels of various metabolites (sugars, fatty acids, and small organic acids) increased after exposure to λ-CY with consequences on bacterial community composition. Maintaining high bacterial alpha diversity and recruiting specific bacterial groups slowed down the loss of rhizosphere nutrients in females. In contrast, the reduction in bacterial alpha diversity and network structure stability in males was associated with lower rhizosphere nutrient availability. Spearman's correlation analysis revealed that several bacterial groups were positively correlated with the root secretion of lipids and organic acids, suggesting that these metabolites can affect the soil bacterial groups actively involved in the nutrient pool. This study provided novel insights that root exudates and soil microbial interactions may mediate sex-specific differences in response to pesticide application.


Assuntos
Praguicidas , Populus , Bactérias , Exsudatos e Transudatos , Ácidos Graxos/metabolismo , Lipídeos , Nitrilas , Praguicidas/metabolismo , Raízes de Plantas/microbiologia , Populus/metabolismo , Piretrinas , Rizosfera , Solo/química , Microbiologia do Solo , Açúcares
8.
Ecol Evol ; 12(7): e9103, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35845380

RESUMO

Deciduous and evergreen trees differ in their responses to drought and nitrogen (N) demand. Whether or not these functional types affect the role of the bacterial community in the N cycle during drought remains uncertain. Two deciduous tree species (Alnus cremastogyne, an N2-fixing species, and Liquidambar formosana) and two evergreen trees (Cunninghamia lanceolata and Pinus massoniana) were used to assess factors in controlling rhizosphere soil bacterial community and N cycling functions. Photosynthetic rates and biomass production of plants, 16S rRNA sequencing and N-cycling-related genes of rhizosphere soil were measured. The relative abundance of the phyla Actinobacteria and Firmicutes was higher, and that of Proteobacteria, Acidobacteria, and Gemmatimondaetes was lower in rhizosphere soil of deciduous trees than that of evergreen. Beta-diversity of bacterial community also significantly differed between the two types of trees. Deciduous trees showed significantly higher net photosynthetic rates and biomass production than evergreen species both at well water condition and short-term drought. Root biomass was the most important factor in driving soil bacterial community and N-cycling functions than total biomass and aboveground biomass. Furthermore, 44 bacteria genera with a decreasing response and 46 taxa showed an increased response along the root biomass gradient. Regarding N-cycle-related functional genes, copy numbers of ammonia-oxidizing bacteria (AOB) and autotrophic ammonia-oxidizing archaea (AOA), N2 fixation gene (nifH), and denitrification genes (nirK, nirS) were significantly higher in the soil of deciduous trees than in that of the evergreen. Structural equation models explained 50.2%, 47.6%, 48.6%, 49.4%, and 37.3% of the variability in copy numbers of nifH, AOB, AOA, nirK, and nirS, respectively, and revealed that root biomass had significant positive effects on copy numbers of all N-cycle functional genes. In conclusion, root biomass played key roles in affecting bacterial community structure and soil N cycling. Our findings have important implications for our understanding of plants control over bacterial community and N-cycling function in artificial forest ecosystems.

9.
Langmuir ; 38(20): 6454-6463, 2022 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-35549353

RESUMO

Plasmonic sensors are promising for ultrasensitive chemical and biological analysis. Gold nanoplates (Au NPLs) show unique geometrical structures with high ratios of surface to bulk atoms, which display fascinating plasmonic properties but require optimization. This study presented a systematic investigation of the influence of different parameters (shape, aspect ratio, and resonance mode) on localized surface plasmon resonance properties, refractive index (RI, n) sensitivities, and surface-enhanced Raman scattering (SERS) enhancement ability of different types of Au NPLs through finite-difference time-domain (FDTD) simulations. As a proof of concept, triangular, circular, and hexagonal Au NPLs with varying aspect ratios were fabricated via a three-step seed-mediated growth method by the experiment. Both FDTD-simulated and measured experimental results confirm that the RI sensitivities increase with the aspect ratio. Furthermore, choosing a lower order resonance mode of Au NPLs benefits higher RI sensitivities. The SERS enhancement abilities of Au NPLs also predicted to be highly dependent on the shape and aspect ratio. The triangular Au NPLs showed the highest SERS enhancement ability, while it drastically decreased for circular Au NPLs after the rounding process. The SERS enhancement ability gradually became more intense as the hexagonal Au NPLs overgrown on circular Au NPLs with increasing volumes of HAuCl4 solution. The results are expected to help develop effective biosensors.


Assuntos
Ouro , Nanopartículas Metálicas , Refratometria , Ouro/química , Nanopartículas Metálicas/química , Refratometria/instrumentação , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/métodos
10.
Eur J Neurosci ; 55(3): 806-826, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35032071

RESUMO

Effortless print-sound integration is essential to reading development, and the superior temporal cortex (STC) is the most critical brain region. However, to date, the conclusion is almost restricted to alphabetic orthographies. To examine the neural basis in non-alphabetic languages and its relationship with reading abilities, we conducted a functional magnetic resonance imaging study in typically developing Chinese children. Two neuroimaging-based indicators of audiovisual processing-additive enhancement (higher activation in the congruent than the average activation of unimodal conditions) and neural integration (different activations between the congruent versus incongruent conditions)-were used to investigate character-sounds (opaque) and pinyin-sounds (transparent) processing. We found additive enhancement in bilateral STCs processing both character and pinyin stimulations. Moreover, the neural integrations in the left STC for the two scripts were strongly correlated. In terms of differentiation, first, areas beyond the STCs also showed additive enhancement in processing pinyin-sounds. Second, while the bilateral STCs, left inferior/middle frontal and parietal regions manifested a striking neural integration (incongruent > congruent) for character-sounds, no significant clusters were revealed for pinyin-sounds. Finally, the neural integration in the left middle frontal gyrus for characters was specifically associated with silent reading comprehension proficiency, indicating automatic semantic processing during implicit character-sound integration. In contrast, the neural integration in the left STC for pinyin was specifically associated with oral reading fluency that relies on grapho-phonological mapping. To summarize, this study revealed both script-universal and script-specific neurofunctional substrates of print-sound integration as well as their processing- and region-dependent associations with reading abilities in typical Chinese children.


Assuntos
Idioma , Fonética , Encéfalo/fisiologia , Mapeamento Encefálico , Criança , China , Humanos , Imageamento por Ressonância Magnética/métodos , Leitura
11.
ACS Appl Nano Mater ; 5(9): 12897-12906, 2022 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-37552747

RESUMO

Coronavirus disease 2019 (COVID-19) remains an ongoing issue worldwide and continues to disrupt daily life. Transmission of infection primarily occurs through secretions when in contact with infected individuals, but more recent evidence has shown that fomites are also a source of virus transmission, especially in cold-chain logistics. Traditional nucleic acid testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contamination in cold-chain logistics is time-consuming and inaccurate because of the multiplex sampling sites. Surface-enhanced Raman spectroscopy (SERS) provides a rapid, sensitive, and label-free detection route for various molecules, including viruses, through the identification of the characteristic peaks of their outer membrane proteins. In this study, we embedded arbitrarily orientated gold nanoplates (Au NPLs) in polydimethylsiloxane (PDMS) elastomer and used it as biosensor for the ultrasensitive detection of the SARS-CoV-2 spike protein in cold-chain logistics. This transparent and flexible substrate can be wrapped onto arbitrary surfaces and permits light penetration into the underlying contact surface, enabling in situ and point-of-care SERS diagnostics. The developed assay displayed high reproducibility (8.7%) and a low detection limit of 6.8 × 10-9 g mL-1, indicating its potential to serve as a promising approach with increased accuracy and sensitivity for the detection of the S protein.

12.
Dev Sci ; 25(3): e13216, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34910843

RESUMO

While the close relationship between the brain system for speech processing and reading development is well-documented in alphabetic languages, whether and how such a link exists in children in a language without systematic grapheme-phoneme correspondence has not been directly investigated. In the present study, we measured Chinese children's brain activation during an auditory lexical decision task with functional magnetic resonance imaging. The results showed that brain areas distributed across the temporal and frontal lobes activated during spoken word recognition. In addition, the left occipitotemporal cortex (OTC) was recruited, especially under the real word condition, thus confirming the involvement of this orthographic-related area in spoken language processing in Chinese children. Importantly, activation of the left temporoparietal cortex (TPC) in response to words and pseudowords was positively correlated with children's reading ability, thus supporting the salient role phonological processing plays in Chinese reading in the developing brain. Furthermore, children with higher reading scores also increasingly recruited the left anterior OTC to make decisions on the lexical status of pseudowords, indicating that higher-skill children tend to search abstract lexical representations more deeply than lower-skill children in deciding whether spoken syllables are real. In contrast, the precuneus was more related to trial-by-trial reaction time in lower-skill children, suggesting that effort-related neural systems differ among pupils with varying reading abilities. Taken together, these findings suggest a strong link between the neural correlates of speech processing and reading ability in Chinese children, thus supporting a universal basis underlying reading development across languages.


Assuntos
Idioma , Leitura , Encéfalo/fisiologia , Mapeamento Encefálico , Criança , China , Humanos , Imageamento por Ressonância Magnética/métodos
13.
Hum Brain Mapp ; 42(14): 4580-4596, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34219304

RESUMO

The importance of (inherited) genetic impact in reading development is well established. De novo mutation is another important contributor that is recently gathering interest as a major liability of neurodevelopmental disorders, but has been neglected in reading research to date. Paternal age at childbirth (PatAGE) is known as the most prominent risk factor for de novo mutation, which has been repeatedly shown by molecular genetic studies. As one of the first efforts, we performed a preliminary investigation of the relationship between PatAGE, offspring's reading, and brain structure in a longitudinal neuroimaging study following 51 children from kindergarten through third grade. The results showed that greater PatAGE was significantly associated with worse reading, explaining an additional 9.5% of the variance after controlling for a number of confounds-including familial factors and cognitive-linguistic reading precursors. Moreover, this effect was mediated by volumetric maturation of the left posterior thalamus from ages 5 to 8. Complementary analyses indicated the PatAGE-related thalamic region was most likely located in the pulvinar nuclei and related to the dorsal attention network by using brain atlases, public datasets, and offspring's diffusion imaging data. Altogether, these findings provide novel insights into neurocognitive mechanisms underlying the PatAGE effect on reading acquisition during its earliest phase and suggest promising areas of future research.


Assuntos
Dislexia , Rede Nervosa , Idade Paterna , Leitura , Tálamo , Criança , Pré-Escolar , Estudos Transversais , Dislexia/diagnóstico por imagem , Dislexia/etiologia , Dislexia/patologia , Dislexia/fisiopatologia , Feminino , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Rede Nervosa/anatomia & histologia , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/crescimento & desenvolvimento , Pulvinar/anatomia & histologia , Pulvinar/diagnóstico por imagem , Pulvinar/crescimento & desenvolvimento , Tálamo/anatomia & histologia , Tálamo/diagnóstico por imagem , Tálamo/crescimento & desenvolvimento
14.
Insect Biochem Mol Biol ; 135: 103608, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34119653

RESUMO

Bacillus thuringiensis (Bt) bacteria produce Cry toxins that kill insect pests. Insect specificity of Cry toxins relies on their binding to larval gut membrane proteins such as cadherin and ATP-binding cassette (ABC) transporter proteins. Mutations in ABC transporters have been implicated in high levels of resistance to Cry toxins in multiple pests. Spodoptera frugiperda is an insect pest susceptible to Cry1Fa and Cry1Ab toxins while Mythimna separata is tolerant to Cry1Fa and less susceptible to Cry1Ab. Here, we analyzed the potential role of ABCC2 in determining the susceptibility of S. frugiperda to Cry1Fa and Cry1Ab, by expressing SfABCC2 or MsABCC2 in Hi5 insect cell line and by the systematic replacements of extracellular loops (ECLs) between these two proteins. Expression of SfABCC2 in Hi5 conferred susceptibility to both Cry1Fa and Cry1Ab, in contrast to the expression of MsABCC2 that mediated low toxicity to Cry1Ab and no toxicity to Cry1Fa in agreement with their larvicidal toxicities. The SfABCC2 and MsABCC2 amino acid sequences showed differential residues among ECL1, ECL2, ECL4 and ECL6 loops, while ECL3 and ECL5 share the same primary sequence. The exchange of ECLs between SfABCC2 and MsABCC2 demonstrated that ECL4 and ECL2 contribute to Cry1Fa toxicity, where ECL4 plays a major role. The medium region (named M2) of ECL4 was identified as the most important region of SfABCC2 involved in Cry1Fa toxicity as shown by point mutations in this region. These findings will be helpful to understand the mechanisms of action of Bt toxins in S. frugiperda.


Assuntos
Toxinas de Bacillus thuringiensis/farmacologia , Resistência a Inseticidas/genética , Mariposas , Proteínas Associadas à Resistência a Múltiplos Medicamentos , Animais , Proteínas de Bactérias/farmacologia , Linhagem Celular , Endotoxinas/farmacologia , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Mariposas/genética , Mariposas/metabolismo , Proteína 2 Associada à Farmacorresistência Múltipla , Proteínas Associadas à Resistência a Múltiplos Medicamentos/química , Spodoptera/efeitos dos fármacos , Spodoptera/genética , Spodoptera/metabolismo
15.
Front Psychol ; 12: 748644, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35145448

RESUMO

Conquering print-sound mappings (e.g., grapheme-phoneme correspondence rules) is vital for developing fluent reading skills. In neuroimaging research, this ability can be indexed by activation differences between audiovisual congruent against incongruent conditions in brain areas such as the left superior temporal cortex. In line with it, individuals with dyslexia have difficulty in tasks requiring print-sound processing, accompanied by a reduced neural integration. However, existing evidence is almost restricted to alphabetic languages. Whether and how multisensory processing of print and sound is impaired in Chinese dyslexia remains underexplored. In this study, we applied a passive audiovisual integration paradigm with functional magnetic resonance imaging to investigate the possible dysfunctions in processing character-sound (opaque; semantics can be automatically accessed) and pinyin-sound associations (transparent; no particular meaning can be confirmed) in Chinese dyslexic children. Unexpectedly, the dyslexic group did not show reduced neural integration compared with typically developing readers in either character or pinyin experiment. However, the results revealed atypical correlations between neural integration and different reading abilities in dyslexia. Specifically, while the neural integration in the left inferior frontal cortex in processing character-sound pairs correlated with silent reading comprehension in both children with and without dyslexia, it was associated with morphological awareness (semantic-related) in controls but with rapid naming (phonological-related) in dyslexics. This result indicates Chinese dyslexic children may not use the same grapho-semantic processing strategy as their typical peers do. As for pinyin-sound processing, while a stronger neural integration in the direction of "congruent > incongruent" in the left occipito-temporal cortex and bilateral superior temporal cortices was associated with better oral reading fluency in the control group, an opposite pattern was found in dyslexia. This finding may reflect dyslexia's dysfunctional recruitment of the regions in grapho-phonological processing, which further impedes character learning.

16.
Front Hum Neurosci ; 14: 567541, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33192396

RESUMO

The role of visual skills in reading acquisition has long been debated and whether there is shared neurobiological basis between visual skills and reading is not clear. This study investigated the relationship between Visual Matching and reading and their shared neuroanatomical basis. Two hundred and ninety-three typically developing Mandarin-speaking children were followed in a longitudinal study from ages 4 to 11 years old. A subsample of 79 children was further followed up at 14 years old when the MRI data were collected. Results showed that the development of Visual Matching from ages 6 to 8 predicted reading accuracy at age 11. In addition, both the development of Visual Matching and reading accuracy were associated with cortical surface area of a cluster located in fusiform gyrus. These findings suggested that the mapping from visual codes to phonological codes is important in learning to read and that left fusiform gyrus provided neural basis for such mapping. Implications of these findings in light of a new approach toward the neurocognitive mechanisms underlying reading development are discussed.

17.
New Phytol ; 225(2): 782-792, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31487045

RESUMO

Soil phosphorus (P) availability and its distribution influence plant growth and productivity, but how they affect the growth dynamics and sex-specific P acquisition strategies of dioecious plant species is poorly understood. In this study, the impact of soil P availability and its distribution on dioecious Populus cathayana was characterized. P. cathayana males and females were grown under three levels of P supply, and with homogeneous or heterogeneous P distribution. Females had a greater total root length, specific root length (SRL), biomass and foliar P concentration under high P supply. Under P deficiency, males had a smaller root system than females but a greater exudation of soil acid phosphatase, and a higher colonization rate and arbuscular mycorrhizal hyphal biomass, suggesting a better capacity to mine P and a stronger association with arbuscular mycorrhizal fungi to forage P. Heterogeneous P distribution enhanced growth and root length density (RLD) in females. Female root proliferation in P-rich patches was related to increased foliar P assimilation. Localized P application for increasing P availability did not enhance the biomass accumulation and the morphological plasticity of roots in males, but it raised hyphal biomass. The findings herein indicate that sex-specific strategies in P acquisition relate to root morphology, root exudation and mycorrhizal symbioses, and they may contribute to sex-specific resource utilization patterns and niche segregation.


Assuntos
Fósforo/metabolismo , Populus/metabolismo , Solo/química , Fosfatase Ácida/metabolismo , Disponibilidade Biológica , Biomarcadores/metabolismo , Biomassa , Ácidos Graxos/metabolismo , Concentração de Íons de Hidrogênio , Fosfolipídeos/metabolismo , Folhas de Planta/metabolismo , Raízes de Plantas/anatomia & histologia , Populus/anatomia & histologia , Rizosfera
18.
Neuroimage ; 201: 116021, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31310862

RESUMO

Learning to read transforms the brain, building on children's existing capacities for language and visuospatial processing. In particular, the development of print-speech convergence, or the spatial overlap of neural regions necessary for both auditory and visual language processing, is critical for literacy acquisition. Print-speech convergence is a universal signature of proficient reading, yet the antecedents of this convergence remain unknown. Here we examine the relationship between spoken language proficiency and the emergence of the print-speech network in beginning readers (ages 5-6). Results demonstrate that children's language proficiency, but not their early literacy skill, explains variance in their print-speech neural convergence in kindergarten. Furthermore, print-speech convergence in kindergarten predicts reading abilities one year later. These findings suggest that children's language ability is a core mechanism guiding the neural plasticity for learning to read, and extend theoretical perspectives on language and literacy acquisition across the lifespan.


Assuntos
Idioma , Aprendizagem/fisiologia , Plasticidade Neuronal/fisiologia , Leitura , Fala/fisiologia , Criança , Pré-Escolar , Feminino , Humanos , Estudos Longitudinais , Masculino
19.
Front Hum Neurosci ; 13: 133, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31057382

RESUMO

Behavioral and imaging studies in alphabetic languages have shown that morphological processing is a discrete and independent element of lexical access. However, there is no explicit marker of morphological structure in Chinese complex words, such that the extent to which morpheme meaning is related to word meaning is unknown. Event-related potentials (ERPs) were used in the present study to investigate the dissociation of morphemic and whole-word meaning in an auditory-auditory primed lexical decision task. All the prime and target words are compounds consisting of two Chinese morphemes. The relationship between morpheme and whole-word meaning was manipulated while controlling the phonology and orthography of the first syllable in each prime-target pair. A clear dissociation was found between morphemic and whole-word meaning on N400 amplitude and topography. Specifically, sharing a morpheme produced a larger N400 in the anterior-central electrode sites, while sharing whole-word meaning produced a smaller N400 in central-posterior electrode sites. In addition, the morphological N400 effect was negatively correlated with the participants' reading ability, with better readers needing less orthographic information to distinguish different morphemes in compound words. These findings indicate that morphological and whole-word meaning are dissociated in spoken Chinese compound word recognition and that even in the spoken language modality, good readers are better able to access the meaning of individual morphemes in Chinese compound word processing.

20.
Tree Physiol ; 39(8): 1342-1357, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30977829

RESUMO

There is a limited understanding of the impacts of global warming on intra- and interspecific plant competition. Resolving this knowledge gap is important for predicting the potential influence of global warming on forests, particularly on high-altitude trees, which are more sensitive to warming. In the present study, effects of intra- and interspecific competition on plant growth and associated physiological, structural and chemical traits were investigated in Abies faxoniana and Picea purpurea seedlings under control (ambient temperature) and elevated temperature (ET, 2 °C above ambient temperature) conditions for 2 years. We found that A. faxoniana and P. purpurea grown under intra- and interspecific competition showed significant differences in dry matter accumulation (DMA), photosynthetic capacity, nutrient absorption, non-structural carbohydrate (NSC) contents and leaf ultrastructure under ET conditions. ET increased leaf, stem and root DMA of both conifers under both competition patterns. Moreover, under ET and interspecific competition, P. purpurea had overall superior competitive capacity characterized by higher organ (leaf, stem and root) and total DMA, height growth rate, net photosynthetic rate, specific leaf area, water use efficiency (δ13C), leaf and root N and NSC concentrations and greater plasticity for absorption of different soil N forms. Thus, the growth of P. purpurea benefitted from the presence of A. faxoniana under ET. Our results demonstrated that ET significantly affects the asymmetric competition patterns in subalpine conifer species. Potential alteration of plant competitive interactions by global warming can influence the composition, structure and functioning of subalpine coniferous forests.


Assuntos
Abies , Picea , Ecologia , Nutrientes , Folhas de Planta , Temperatura , Árvores
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...