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1.
Plant J ; 115(6): 1699-1715, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37300848

RESUMO

Plant architecture, lodging resistance, and yield are closely associated with height. In this paper, we report the identification and characterization of two allelic EMS-induced mutants of Zea mays, xyl-1, and xyl-2 that display dwarf phenotypes. The mutated gene, ZmXYL, encodes an α-xylosidase which functions in releasing xylosyl residue from a ß-1,4-linked glucan chain. Total α-xylosidase activity in the two alleles is significantly decreased compared to wild-type plants. Loss-of-function mutants of ZmXYL resulted in a decreased xylose content, an increased XXXG content in xyloglucan (XyG), and a reduced auxin content. We show that auxin has an antagonistic effect with XXXG in promoting cell divisions within mesocotyl tissue. xyl-1 and xyl-2 were less sensitive to IAA compared to B73. Based on our study, a model is proposed that places XXXG, an oligosaccharide derived from XyG and the substrate of ZmXYL, as having a negative impact on auxin homeostasis resulting in the dwarf phenotypes of the xyl mutants. Our results provide a insight into the roles of oligosaccharides released from plant cell walls as signals in mediating plant growth and development.


Assuntos
Xilosidases , Zea mays , Zea mays/genética , Ácidos Indolacéticos , Oligossacarídeos/química , Plantas/genética
2.
Anal Chem ; 95(15): 6271-6278, 2023 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-37017609

RESUMO

Sensitive and high-throughput analysis of trace elements in volume-limited biological samples is highly desirable for clinical research and health risk assessments. However, the conventional pneumatic nebulization (PN) sample introduction is usually inefficient and not well-suited for this requirement. Herein, a novel high-efficiency (nearly 100% sample introduction efficiency) and low-sample-consumption introduction device was developed and successfully coupled with inductively coupled plasma quadrupole mass spectrometry (ICP-QMS). It consists of a micro-ultrasonic nebulization (MUN) component with an adjustable nebulization rate and a no-waste spray chamber designed based on fluid simulation. The proposed MUN-ICP-QMS could achieve sensitive analysis at a low sampling rate of 10 µL min-1 with an extremely low oxide ratio of 0.25% where the sensitivity is even higher comparing to PN (100 µL min-1). The characterization results indicate that the higher sensitivity of MUN is attributed to the smaller aerosol size, higher aerosol transmission efficiency, and improved ion extraction. In addition, it offers a fast washout (20 s) and reduced sample consumption (as low as 7 µL). The absolute LODs of the studied 26 elements by MUN-ICP-QMS are improved by 1-2 orders of magnitude compared with PN-ICP-QMS. The accuracy of the proposed method was validated by the analysis of human serum, urine, and food-related certified reference materials. Furthermore, preliminary results of serum samples from patients with mental illnesses demonstrated its potential in the field of metallomics.


Assuntos
Oligoelementos , Ultrassom , Humanos , Espectrometria de Massas/métodos , Oligoelementos/análise , Análise Espectral , Limite de Detecção
3.
Hum Mol Genet ; 29(3): 459-470, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31943016

RESUMO

Autism spectrum disorders are associated with some degree of developmental regression in up to 30% of all cases. Rarely, however, is the regression so extreme that a developmentally advanced young child would lose almost all ability to communicate and interact with her surroundings. We applied trio whole exome sequencing to a young woman who experienced extreme developmental regression starting at 2.5 years of age and identified compound heterozygous nonsense mutations in TMPRSS9, which encodes for polyserase-1, a transmembrane serine protease of poorly understood physiological function. Using semiquantitative polymerase chain reaction, we showed that Tmprss9 is expressed in various mouse tissues, including the brain. To study the consequences of TMPRSS9 loss of function on the mammalian brain, we generated a knockout mouse model. Through a battery of behavioral assays, we found that Tmprss9-/- mice showed decreased social interest and social recognition. We observed a borderline recognition memory deficit by novel object recognition in aged Tmprss9-/- female mice, but not in aged Tmprss9-/- male mice or younger adult Tmprss9-/- mice in both sexes. This study provides evidence to suggest that loss of function variants in TMPRSS9 are related to an autism spectrum disorder. However, the identification of more individuals with similar phenotypes and TMPRSS9 loss of function variants is required to establish a robust gene-disease relationship.


Assuntos
Transtornos de Ansiedade/patologia , Transtorno do Espectro Autista/patologia , Códon sem Sentido , Sequenciamento do Exoma/métodos , Proteínas de Membrana/metabolismo , Transtornos da Memória/patologia , Serina Endopeptidases/metabolismo , Serina Endopeptidases/fisiologia , Adolescente , Adulto , Animais , Transtornos de Ansiedade/etiologia , Transtorno do Espectro Autista/etiologia , Transtorno do Espectro Autista/genética , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Proteínas de Membrana/genética , Transtornos da Memória/etiologia , Camundongos , Camundongos Knockout , Atividade Motora , Fenótipo , Serina Endopeptidases/genética
4.
Am J Hum Genet ; 102(2): 296-308, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29395075

RESUMO

15q13.3 microdeletion syndrome is characterized by a wide spectrum of neurodevelopmental disorders, including developmental delay, intellectual disability, epilepsy, language impairment, abnormal behaviors, neuropsychiatric disorders, and hypotonia. This syndrome is caused by a deletion on chromosome 15q, which typically encompasses six genes. Here, through studies on OTU deubiquitinase 7A (Otud7a) knockout mice, we identify OTUD7A as a critical gene responsible for many of the cardinal phenotypes associated with 15q13.3 microdeletion syndrome. Otud7a-null mice show reduced body weight, developmental delay, abnormal electroencephalography patterns and seizures, reduced ultrasonic vocalizations, decreased grip strength, impaired motor learning/motor coordination, and reduced acoustic startle. We show that OTUD7A localizes to dendritic spines and that Otud7a-null mice have decreased dendritic spine density compared to their wild-type littermates. Furthermore, frequency of miniature excitatory postsynaptic currents (mEPSCs) is reduced in the frontal cortex of Otud7a-null mice, suggesting a role of Otud7a in regulation of dendritic spine density and glutamatergic synaptic transmission. Taken together, our results suggest decreased OTUD7A dosage as a major contributor to the neurodevelopmental phenotypes associated with 15q13.3 microdeletion syndrome, through the misregulation of dendritic spine density and activity.


Assuntos
Transtornos Cromossômicos/enzimologia , Transtornos Cromossômicos/genética , Enzimas Desubiquitinantes/genética , Endopeptidases/genética , Deficiência Intelectual/enzimologia , Deficiência Intelectual/genética , Convulsões/enzimologia , Convulsões/genética , Potenciais de Ação , Animais , Sequência de Bases , Comportamento Animal , Deleção Cromossômica , Cromossomos Humanos Par 15/enzimologia , Cromossomos Humanos Par 15/genética , Espinhas Dendríticas/metabolismo , Modelos Animais de Doenças , Eletroencefalografia , Endopeptidases/deficiência , Epilepsia/enzimologia , Epilepsia/genética , Epilepsia/fisiopatologia , Feminino , Homozigoto , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Sinapses/metabolismo
5.
Nature ; 526(7573): 430-4, 2015 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-26469053

RESUMO

Deep brain stimulation (DBS) has improved the prospects for many individuals with diseases affecting motor control, and recently it has shown promise for improving cognitive function as well. Several studies in individuals with Alzheimer disease and in amnesic rats have demonstrated that DBS targeted to the fimbria-fornix, the region that appears to regulate hippocampal activity, can mitigate defects in hippocampus-dependent memory. Despite these promising results, DBS has not been tested for its ability to improve cognition in any childhood intellectual disability disorder. Such disorders are a pressing concern: they affect as much as 3% of the population and involve hundreds of different genes. We proposed that stimulating the neural circuits that underlie learning and memory might provide a more promising route to treating these otherwise intractable disorders than seeking to adjust levels of one molecule at a time. We therefore studied the effects of forniceal DBS in a well-characterized mouse model of Rett syndrome (RTT), which is a leading cause of intellectual disability in females. Caused by mutations that impair the function of MeCP2 (ref. 6), RTT appears by the second year of life in humans, causing profound impairment in cognitive, motor and social skills, along with an array of neurological features. RTT mice, which reproduce the broad phenotype of this disorder, also show clear deficits in hippocampus-dependent learning and memory and hippocampal synaptic plasticity. Here we show that forniceal DBS in RTT mice rescues contextual fear memory as well as spatial learning and memory. In parallel, forniceal DBS restores in vivo hippocampal long-term potentiation and hippocampal neurogenesis. These results indicate that forniceal DBS might mitigate cognitive dysfunction in RTT.


Assuntos
Estimulação Encefálica Profunda , Fórnice/fisiologia , Hipocampo/fisiologia , Hipocampo/fisiopatologia , Memória/fisiologia , Síndrome de Rett/psicologia , Síndrome de Rett/terapia , Animais , Cognição/fisiologia , Transtornos Cognitivos/complicações , Transtornos Cognitivos/fisiopatologia , Transtornos Cognitivos/psicologia , Transtornos Cognitivos/terapia , Modelos Animais de Doenças , Medo/fisiologia , Medo/psicologia , Feminino , Fórnice/citologia , Fórnice/fisiopatologia , Hipocampo/citologia , Potenciação de Longa Duração/fisiologia , Camundongos , Neurogênese , Síndrome de Rett/genética , Síndrome de Rett/fisiopatologia , Aprendizagem Espacial/fisiologia
6.
Gene ; 933: 148927, 2024 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-39255860

RESUMO

Cadmium (Cd) is a harmful heavy metal that is highly toxic to plants and animals. Expansins are cell wall proteins inducing cell wall loosening and participate in all plant growth and development processes which are associated with cell wall modifications. We investigated lettuce's expansin gene LsEXPA6 and found that LsEXPA6 overexpression Arabidopsis lines were much more resistant to cadmium stress. Our results revealed that the root system of the expa6 mutant was suppressed under cadmium stress, resulting in shorter plant height, reduced biomass, and a significant increase in cadmium content in the plants compared with wild-type plants, whereas LsEXPA6 overexpression lines had a well-developed root system and reduced cadmium accumulation in the roots and shoots of the plants. The above results indicated that overexpression of LsEXPA6 affected root development and reduced Cd absorption in Arabidopsis. In addition, the higher absorption capacity of nutrients, increased antioxidant enzymes activities, improved chlorophyll and photosynthetic function in the overexpression Arabidopsis plants, supported the Cd stress tolerance mechanism. Taken together, these results provided a new insight on the role of expansin proteins in the tolerance of plants to Cd stress by root cell elongation.

7.
eNeuro ; 6(6)2019.
Artigo em Inglês | MEDLINE | ID: mdl-31562178

RESUMO

Rett Syndrome is a neurological disorder caused by mutations in the gene encoding methyl CpG binding protein 2 (MeCP2) and characterized by severe intellectual disability. The cholinergic system is a critical modulator of cognitive ability and is affected in patients with Rett Syndrome. To better understand the importance of MeCP2 function in cholinergic neurons, we studied the effect of selective Mecp2 deletion from cholinergic neurons in mice. Mice with Mecp2 deletion from cholinergic neurons were selectively impaired in assays of recognition memory, a cognitive task largely mediated by the perirhinal cortex (PRH). Deletion of Mecp2 from cholinergic neurons resulted in profound alterations in baseline firing of L5/6 neurons and eliminated the responses of these neurons to optogenetic stimulation of cholinergic input to PRH. Both the behavioral and the electrophysiological deficits of cholinergic Mecp2 deletion were rescued by inhibiting ACh breakdown with donepezil treatment.


Assuntos
Neurônios Colinérgicos/metabolismo , Proteína 2 de Ligação a Metil-CpG/metabolismo , Córtex Perirrinal/metabolismo , Reconhecimento Psicológico/fisiologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Animais , Neurônios Colinérgicos/efeitos dos fármacos , Inibidores da Colinesterase/farmacologia , Modelos Animais de Doenças , Donepezila/farmacologia , Proteína 2 de Ligação a Metil-CpG/genética , Camundongos , Camundongos Knockout , Optogenética , Córtex Perirrinal/efeitos dos fármacos , Fenótipo , Reconhecimento Psicológico/efeitos dos fármacos , Síndrome de Rett/genética , Síndrome de Rett/metabolismo
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