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1.
Cell Rep ; 43(3): 113864, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38421870

RESUMO

The neural mechanisms underlying novelty detection are not well understood, especially in relation to behavior. Here, we present single-unit responses from the primary auditory cortex (A1) from two monkeys trained to detect deviant tones amid repetitive ones. Results show that monkeys can detect deviant sounds, and there is a strong correlation between late neuronal responses (250-350 ms after deviant onset) and the monkeys' perceptual decisions. The magnitude and timing of both neuronal and behavioral responses are increased by larger frequency differences between the deviant and standard tones and by increasing the number of standard tones preceding the deviant. This suggests that A1 neurons encode novelty detection in behaving monkeys, influenced by stimulus relevance and expectations. This study provides evidence supporting aspects of predictive coding in the sensory cortex.


Assuntos
Córtex Auditivo , Potenciais Evocados Auditivos , Potenciais Evocados Auditivos/fisiologia , Estimulação Acústica/métodos , Córtex Auditivo/fisiologia , Neurônios/fisiologia
2.
J Agric Food Chem ; 68(50): 14739-14747, 2020 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-33264024

RESUMO

Carbaryl is a widely used carbamate pesticide in agriculture. The strain Rhizobium sp. X9 possesses the typical carbaryl degradation pathway in which carbaryl is mineralized via 1-naphthol, salicylate, and gentisate. In this study, we cloned a carbaryl hydrolase gene cehA and a novel two-component 1-naphthol hydroxylase gene cehC1C2. CehA mediates carbaryl hydrolysis to 1-naphthol and CehC1, an FMNH2 or FADH2-dependent monooxygenase belonging to the HpaB superfamily, and hydroxylates 1-naphthol in the presence of reduced nicotinamide-adenine dinucleotide (FMN)/flavin adenine dinucleotide (FAD), and the reductase CehC2. CehC1 has the highest amino acid similarity (58%) with the oxygenase component of a two-component 4-nitrophenol 2-monooxygenase, while CehC2 has the highest amino acid similarity (46%) with its reductase component. CehC1C2 could utilize both FAD and FMN as the cofactor during the hydroxylation, although higher catalytic activity was observed with FAD as the cofactor. The optimal molar ratio of CehC1 to CehC2 was 2:1. The Km and Kcat/Km values of CehC1 for 1-naphthol were 74.71 ± 16.07 µM and (8.29 ± 2.44) × 10-4 s-1·µM-1, respectively. Moreover, the enzyme activities and substrate spectrum between CehC1C2 and previously reported 1-naphthol hydroxylase McbC were compared. The results suggested that McbC had a higher 1-naphthol hydroxylation activity, while CehC1C2 had a broader substrate spectrum.


Assuntos
Proteínas de Bactérias/metabolismo , Carbaril/metabolismo , Hidrolases/metabolismo , Oxigenases de Função Mista/metabolismo , Rhizobium/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Biodegradação Ambiental , Coenzimas/metabolismo , Mononucleotídeo de Flavina/metabolismo , Flavina-Adenina Dinucleotídeo/metabolismo , Hidrolases/química , Hidrolases/genética , Cinética , Oxigenases de Função Mista/química , Oxigenases de Função Mista/genética , Naftóis/metabolismo , Praguicidas/química , Praguicidas/metabolismo , Rhizobium/química , Rhizobium/enzimologia , Rhizobium/genética
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