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1.
Braz J Biol ; 83: e269165, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37075424

RESUMO

The insect group is one of the most diverse on the planet and due to habitat degradation, many of these species are becoming extinct, leaving a lack of information on the basic biology of each one. In this study, previously unseen information about nesting biology is revealed in Auplopus subaurarius trap nests. This is a solitary ectoparasitoid spider wasp that nests in preexisting cavities. We used a trap-nesting methodology to sample A. subaurarius in two different sampling periods (2017/2018 and 2020/2021) in three types of environment (forest, grassland and Eucalyptus plantation). In our study, the A. subaurarius nest building was more frequent during the hottest months of the year (November to March), with its highest abundance found within natural forest areas and in Eucalyptus plantation than in grassland areas. In addition, the species had two development times: a short one (three months) and a delayed one (up to one year). Moreover, females were larger than males (weight and size) and the species' sex ratio had a tendency toward female production. Auplopus subaurarius presented seven natural enemy species: Ceyxia longispina, Caenochrysis crotonis, Photochryptus sp.1, Photochryptus sp.2, Messatoporus sp., Ephuta icema and Sphaeropthalma sp. We emphasize the importance of wooded environments to maintain the A. subaurarius populations and their associated interactors, both spiders and natural enemies, as these environments can provide better life conditions than grassland areas. Furthermore, other solitary wasps that may have the same lifestyle of A. subaurarius can also be improved by natural forest conservation and by good silviculture plantation planning, which should consider ecological aspects of Atlantic Forest landscapes.


Assuntos
Eucalyptus , Vespas , Feminino , Animais , Masculino , Comportamento de Nidação , Florestas , Ecossistema , Biologia
2.
Braz J Biol ; 83: e266746, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36856250

RESUMO

During an inventory of Ichneumonidae wasps in the urban area of São Carlos, São Paulo, using Malaise traps, was found the first records in Brazil for Lissonota pseudeleboea Ugalde and Gauld, 2002 and Syzeuctus vedoris Ugalde and Gauld, 2002 (Hymenoptera, Ichneumonidae, Banchinae) and was described and illustrated a new species of Zonopimpla Ashmead (Hymenoptera, Ichneumonidae, Pimplinae).


Assuntos
Vespas , Animais , Brasil
3.
Arq. bras. med. vet. zootec. (Online) ; 73(3): 658-664, May-June 2021. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1278358

RESUMO

Most sandy soils have low natural fertility and low levels of organic matter, making nitrogen (N) fertilization essential. Thus, five doses of N were applied (0, 75, 125, 175 and 225mg dm-³) in a randomized block design to evaluate the effects of nitrogen fertilization on the morphogenetic, structural and production characteristics of Brachiaria brizantha cv. Marandu in a Quartzarenic neosoil. The doses of N did not affect the height of the canopy. The leaf elongation rate, final leaf length and number of live leaves increased linearly at the doses of N. Leaf appearance rate, stem elongation rate, leaf lifespan, phyllochron, leaf senescence rate and tiller density showed a quadratic response to the rates There was also an effect of N rates in herbage mass, leaf mass, stem mass, which increased linearly. Brachiaria brizantha cv. Marandu cultivated in Quartzarenic neosoil requires higher doses of N, 175 and 225mg dm-³. Under these conditions, increases in its morphogenetic, structural and productive characteristics are observed. These findings may not be repeated in the most fertile soils with the greatest capacity to supply N.(AU)


A maioria dos solos arenosos tem baixa fertilidade natural e baixos teores de matéria orgânica, tornando a adubação com nitrogênio (N) essencial. Assim, foram aplicadas cinco doses de N (0, 75, 125, 175 e 225mg dm-³) em delineamento de blocos ao acaso, para se avaliarem os efeitos da adubação com nitrogênio nas características morfogênicas, estruturais e produtivas da Brachiaria brizantha cv. Marandu, em um Neossolo Quartzarênico. As doses de N não afetaram a altura do dossel. A taxa de alongamento foliar, o comprimento final da folha e o número de folhas vivas aumentaram linearmente em função das doses de N. A taxa de aparecimento de folhas, a taxa de alongamento do caule, o tempo de vida da folha, o filocrono, a taxa de senescência foliar e a densidade de perfilhos apresentaram resposta quadrática às doses de N. A massa da forragem, a massa foliar e a massa do caule aumentaram linearmente. Brachiaria brizantha cv. Marandu cultivada em Neossolo Quartzarênico requer maiores doses de N, 175 e 225mg dm-³. Nessas condições, são observados aumentos em suas características morfogenéticas, estruturais e produtivas. Esses achados podem não se repetir nos solos mais férteis e com maior capacidade de suprir N.(AU)


Assuntos
Ureia , Brachiaria/anatomia & histologia , Brachiaria/química , Características do Solo/análise , Compostagem
4.
Braz. j. biol ; 80(3): 669-672, July-Sept. 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1132405

RESUMO

Abstract Lymeon Förster, 1869 is a very large genus of the Cryptinae (Ichneumonidae) with predominantly Neotropical distribution where females attack small cocoons of various groups of insects and spider eggs-sac. In the present study, we report the first record the interaction between the parasitoid wasp Lymeon sp. (Ichneumonidae), with eggs-sac of spider Araneus vincibilis (Araneidae) in Northeastern Brazil. We observed that although the female of A. vincibilis cares for the eggs that were attacked by Lymeon sp, the wasp larva consumed about 80% of spider eggs, indicating that both maternal care and the physical barrier offered by the eggs-sac may not provide absolute defense against predators.


Resumo Lymeon Förster, 1869 é um grande gênero de Cryptinae (Ichneumonidae) com distribuição predominantemente neotropical, onde fêmeas atacam pequenos casulos de vários grupos de insetos e ovissacos de aranha. No presente estudo, relatamos o primeiro registro da interação entre a vespa parasitoide Lymeon sp. (Ichneumonidae), com o ovissaco da aranha Araneus vincibilis (Araneidae) no Nordeste do Brasil. Observamos que, embora a fêmea de A. vincibilis cuide dos ovos que foram atacados por Lymeon sp, a larva da vespa consumiu cerca de 80% dos ovos da aranha, indicando que tanto o cuidado maternal quanto a barreira física oferecida pelo ovissaco não podem fornecer defesa absoluta contra predadores.


Assuntos
Animais , Feminino , Aranhas , Vespas , Brasil , Larva
5.
Braz. j. biol ; 80(2): 377-385, Apr.-June 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1132377

RESUMO

Abstract In this study the diversity of Pimplinae at three different altitude zones in the Reserva Biológica da Serra do Japi Jundiaí, SP, Brazil was investigated with a total of 18 genera and 91 morphospecies collected by Malaise traps. Highest abundance and richness of Pimplinae were found in low and high altitudes, respectively. In the intermediate altitude occurred greater diversity and equitability, with greater similarity to high altitude. The genera Pimpla and Neotheronia were the most abundant; Pimpla caerulea Brullé, 1846 was the most frequent species. A new species of the genus Acrotaphus and two new species of the genus Polysphincta were found. Descriptions of the new species and identification keys are presented.


Resumo Neste estudo a diversidade de Pimplinae em três diferentes altitudes na Reserva Biológica da Serra do Japi, Jundiaí, SP, Brasil foi investigada com um total de 18 gêneros e 91 morfoespécies capturadas por armadilhas Malaise. Nas altitudes baixa e alta ocorreram maior abundância e riqueza em gêneros, respectivamente. Na altitude intermediária ocorreu maior diversidade e equitabilidade, com maior similaridade na altitude alta. Os gêneros Pimpla e Neotheronia foram os mais abundantes. Pimpla caerulea Brullé, 1846 foi a espécie mais frequente. Uma nova espécie do gênero Acrotaphus e duas novas espécies do gênero Polysphincta foram encontradas. As descrições das novas espécies e as chaves de identificação são apresentadas.


Assuntos
Animais , Vespas , Himenópteros , Brasil , Altitude
6.
Braz. j. biol ; 80(2): 240-244, Apr.-June 2020. graf
Artigo em Inglês | LILACS | ID: biblio-1132381

RESUMO

Abstract Platydoryctes Barbalho and Penteado-Dias 2000 is a small genus of Neotropical parasitoid wasps (Hymenoptera: Braconidae: Doryctinae) with four described species to date. Two new species of the genus are described from Brazil, and a key to species is presented in this paper.


Resumo Platydoryctes Barbalho and Penteado-Dias 2000 é um pequeno gênero Neotropical de vespas parasitoides (Hymenoptera: Braconidae: Doryctinae), com quatro espécies descritas até o presente. Duas novas espécies do gênero são descritas para o Brasil e uma chave para espécies é apresentada neste trabalho.


Assuntos
Animais , Vespas , Himenópteros , Brasil
7.
Braz J Biol ; 80(2): 240-244, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31291397

RESUMO

Platydoryctes Barbalho and Penteado-Dias 2000 is a small genus of Neotropical parasitoid wasps (Hymenoptera: Braconidae: Doryctinae) with four described species to date. Two new species of the genus are described from Brazil, and a key to species is presented in this paper.


Assuntos
Himenópteros , Vespas , Animais , Brasil
8.
Braz J Biol ; 80(3): 669-672, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31596362

RESUMO

Lymeon Förster, 1869 is a very large genus of the Cryptinae (Ichneumonidae) with predominantly Neotropical distribution where females attack small cocoons of various groups of insects and spider eggs-sac. In the present study, we report the first record the interaction between the parasitoid wasp Lymeon sp. (Ichneumonidae), with eggs-sac of spider Araneus vincibilis (Araneidae) in Northeastern Brazil. We observed that although the female of A. vincibilis cares for the eggs that were attacked by Lymeon sp, the wasp larva consumed about 80% of spider eggs, indicating that both maternal care and the physical barrier offered by the eggs-sac may not provide absolute defense against predators.


Assuntos
Aranhas , Vespas , Animais , Brasil , Feminino , Larva
9.
Braz J Biol ; 80(2): 377-385, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31116298

RESUMO

In this study the diversity of Pimplinae at three different altitude zones in the Reserva Biológica da Serra do Japi Jundiaí, SP, Brazil was investigated with a total of 18 genera and 91 morphospecies collected by Malaise traps. Highest abundance and richness of Pimplinae were found in low and high altitudes, respectively. In the intermediate altitude occurred greater diversity and equitability, with greater similarity to high altitude. The genera Pimpla and Neotheronia were the most abundant; Pimpla caerulea Brullé, 1846 was the most frequent species. A new species of the genus Acrotaphus and two new species of the genus Polysphincta were found. Descriptions of the new species and identification keys are presented.


Assuntos
Himenópteros , Vespas , Altitude , Animais , Brasil
10.
Mycopathologia ; 184(6): 775-786, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31679132

RESUMO

Candida can adhere and form biofilm on biomaterials commonly used in medical devices which is a key attribute that enhances its ability to cause infections in humans. Furthermore, biomaterial-related infections represent a major therapeutic challenge since Candida biofilms are implicated in antifungal therapies failure. The goals of the present work were to investigate the effect of three 5-aminoimidazole-4-carbohydrazonamides, namely (Z)-5-amino-1-methyl-N'-aryl-1H-imidazole-4-carbohydrazonamides [aryl = phenyl (1a), 4-fluorophenyl (1b), 3-fluorophenyl (1c)], on Candida albicans and Candida krusei biofilm on nanohydroxyapatite substrate, a well-known bioactive ceramic material. To address these goals, both quantitative methods (by cultivable cell numbers) and qualitative evaluation (by scanning electron microscopy) were used. Compounds cytocompatibility towards osteoblast-like cells was also evaluated after 24 h of exposure, through resazurin assay. The three tested compounds displayed a strong inhibitory effect on biofilm development of both Candida species as potent in vitro activity against C. albicans sessile cells. Regarding cytocompatibility, a concentration-dependent effect was observed. Together, these findings indicated that the potent activity of imidazole derivatives on Candida spp. biofilms on nanohydroxyapatite substrate, in particular compound 1c, is worth further investigating.


Assuntos
Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Candida , Próteses e Implantes/microbiologia , Infecções Relacionadas à Prótese/tratamento farmacológico , Materiais Biocompatíveis , Biofilmes/crescimento & desenvolvimento , Candida/efeitos dos fármacos , Candida/crescimento & desenvolvimento , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Linhagem Celular/efeitos dos fármacos , Humanos , Imidazóis/farmacologia , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Osteoblastos/efeitos dos fármacos , Infecções Relacionadas à Prótese/microbiologia
12.
Schizophr Res Cogn ; 12: 20-28, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29552509

RESUMO

BACKGROUND: The lack of efficacy of pharmacological treatments for cognitive and negative symptoms in schizophrenia highlights the need for new interventions. We investigated the effects of tDCS on working memory and negative symptoms in patients with schizophrenia. METHOD: Double-blinded, randomized, sham-controlled clinical trial, investigating the effects of 10 sessions of tDCS in schizophrenia subjects. Stimulation used 2 mA, for 20 min, with electrodes of 25 cm2 wrapped in cotton material soaked in saline solution. Anode was positioned over the left DLPFC and the cathode in the contralateral area. Twenty-four participants were assessed at baseline, after intervention and in a three-months follow-up. The primary outcome was the working memory score from MATRICS and the secondary outcome the negative score from PANSS. Data were analyzed using generalized estimating equations. RESULTS: We did not find group ∗ time interaction for the working memory (p = 0.720) score or any other cognitive variable (p > 0.05). We found a significant group ∗ time interaction for PANSS negative (p < 0.001, d = 0.23, CI.95 = -0.59-1.02), general (p = 0.011) and total scores (p < 0.001). Exploratory analysis of PANSS 5 factors suggests tDCS effect on PANSS negative (p = 0.012), cognitive (p = 0.016) and depression factors (p = 0.029). CONCLUSION: The results from this trial highlight the therapeutic effects of tDCS for treatment of persistent symptoms in schizophrenia, with reduction of negative symptoms. We were not able to confirm the superiority of active tDCS over sham to improve working memory performance. Larger sample size studies are needed to confirm these findings.

13.
Schizophr Res ; 195: 591-593, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-28882685

RESUMO

BACKGROUND: Cognitive impairments in schizophrenia are strongly correlated to functional outcome and recovery rates, with no pharmacological agent approved for its treatment. Neurofeedback has emerged as a non-pharmacological approach to enhance neuroplasticity, which consists in inducing voluntary control of brain responses through operant conditioning. METHOD: The effects of hemoencephalography neurofeedback (HEG-NFBK) in 4 brain sites (F7, Fp1, Fp2 and F8) was studied in 8 patients with schizophrenia (SCH, mean age 36.5±9.98) and 12 health controls (mean age 32.17±5.6). We analyzed groups' performance (10 sessions) and cognitive differences in 3 time points (baseline, after training and follow-up) with generalized estimated equations. For SCH we also evaluate the impact on psychopathology. RESULTS: We found a group∗time interaction for HEG-NFBK performance in the left hemisphere sites (F7 an Fp1) and a near-to-significant in the right frontotemporal region (F8), with no group differences and a significant time effect. Most of cognitive domains improved after intervention, including information processing speed, attention processing, working memory, executive functioning, verbal and visual learning. No group∗time interaction was found. Results suggest that both groups benefit from HEG-NFBK training regardless of cognitive differences at baseline. No significant time effects were found for Calgary and PANSS total scale and subscales (positive, negative neither general). CONCLUSION: To our knowledge, this is the first controlled trial showing effects of NFBK on cognitive performance improvement in schizophrenia. Further research investigating the effects of HEG-NFBK training in schizophrenia should be performed.


Assuntos
Transtornos Cognitivos/etiologia , Transtornos Cognitivos/reabilitação , Neurorretroalimentação/métodos , Esquizofrenia/complicações , Psicologia do Esquizofrênico , Adulto , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estatísticas não Paramétricas
14.
Mater Sci Eng C Mater Biol Appl ; 77: 333-341, 2017 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-28532037

RESUMO

This work evaluates the effect of processing variables on some physicochemical and mechanical properties of multi- and unidirectional laminar collagen type I scaffolds. The processing variables considered in this study included microstructure orientation (uni- and multidirectional fiber/pore controlled by freeze-drying methodology), cross-linking (chemical - using genipin and glutaraldehyde, and physical - using a dehydrothermal method), and collagen concentration (2, 5 and 8mg/ml). The biocompatibility of the scaffolds obtained in each of the evaluated manufacturing processes was also assessed. Despite previous research on collagen-based platforms, the effects that these processing variables have on the properties of collagen scaffolds are still not completely understood. Unidirectional scaffolds presented higher resistance to failure under stress than multidirectional ones. The cross-linking degree was found to decrease when the concentration of collagen increased whilst using chemical cross-linkers, and to increase with the concentration of collagen for the dehydrothermal cross-linked scaffolds. Pore orientation indexes of both unidirectional and multidirectional scaffolds were not influenced by collagen concentration. Cross-linked scaffolds were more hydrophobic than non-cross-linked ones, and presented water vapor permeability adequate for use in low-to-moderate exuding wounds. Pore size ranges were compatible with cell in-growth, independently of the employed cross-linking and freezing methodologies. Moreover, scaffolds cross-linked with glutaraldehyde presented higher in-growth of primary oral mucosa fibroblasts than those cross-linked with genipin or with the dehydrothermal treatment. This multi-factor analysis is expected to contribute to the design of collagen type I platforms, which are usable on several potential soft tissue-engineering applications.


Assuntos
Reagentes de Ligações Cruzadas/química , Materiais Biocompatíveis , Colágeno Tipo I , Teste de Materiais , Engenharia Tecidual , Tecidos Suporte
15.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1467284

RESUMO

Abstract In this study the diversity of Pimplinae at three different altitude zones in the Reserva Biológica da Serra do Japi Jundiaí, SP, Brazil was investigated with a total of 18 genera and 91 morphospecies collected by Malaise traps. Highest abundance and richness of Pimplinae were found in low and high altitudes, respectively. In the intermediate altitude occurred greater diversity and equitability, with greater similarity to high altitude. The genera Pimpla and Neotheronia were the most abundant; Pimpla caerulea Brullé, 1846 was the most frequent species. A new species of the genus Acrotaphus and two new species of the genus Polysphincta were found. Descriptions of the new species and identification keys are presented.


Resumo Neste estudo a diversidade de Pimplinae em três diferentes altitudes na Reserva Biológica da Serra do Japi, Jundiaí, SP, Brasil foi investigada com um total de 18 gêneros e 91 morfoespécies capturadas por armadilhas Malaise. Nas altitudes baixa e alta ocorreram maior abundância e riqueza em gêneros, respectivamente. Na altitude intermediária ocorreu maior diversidade e equitabilidade, com maior similaridade na altitude alta. Os gêneros Pimpla e Neotheronia foram os mais abundantes. Pimpla caerulea Brullé, 1846 foi a espécie mais frequente. Uma nova espécie do gênero Acrotaphus e duas novas espécies do gênero Polysphincta foram encontradas. As descrições das novas espécies e as chaves de identificação são apresentadas.

16.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1467288

RESUMO

Abstract Platydoryctes Barbalho and Penteado-Dias 2000 is a small genus of Neotropical parasitoid wasps (Hymenoptera: Braconidae: Doryctinae) with four described species to date. Two new species of the genus are described from Brazil, and a key to species is presented in this paper.


Resumo Platydoryctes Barbalho and Penteado-Dias 2000 é um pequeno gênero Neotropical de vespas parasitoides (Hymenoptera: Braconidae: Doryctinae), com quatro espécies descritas até o presente. Duas novas espécies do gênero são descritas para o Brasil e uma chave para espécies é apresentada neste trabalho.

17.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1467328

RESUMO

Abstract Lymeon Förster, 1869 is a very large genus of the Cryptinae (Ichneumonidae) with predominantly Neotropical distribution where females attack small cocoons of various groups of insects and spider eggs-sac. In the present study, we report the first record the interaction between the parasitoid wasp Lymeon sp. (Ichneumonidae), with eggs-sac of spider Araneus vincibilis (Araneidae) in Northeastern Brazil. We observed that although the female of A. vincibilis cares for the eggs that were attacked by Lymeon sp, the wasp larva consumed about 80% of spider eggs, indicating that both maternal care and the physical barrier offered by the eggs-sac may not provide absolute defense against predators.


Resumo Lymeon Förster, 1869 é um grande gênero de Cryptinae (Ichneumonidae) com distribuição predominantemente neotropical, onde fêmeas atacam pequenos casulos de vários grupos de insetos e ovissacos de aranha. No presente estudo, relatamos o primeiro registro da interação entre a vespa parasitoide Lymeon sp. (Ichneumonidae), com o ovissaco da aranha Araneus vincibilis (Araneidae) no Nordeste do Brasil. Observamos que, embora a fêmea de A. vincibilis cuide dos ovos que foram atacados por Lymeon sp, a larva da vespa consumiu cerca de 80% dos ovos da aranha, indicando que tanto o cuidado maternal quanto a barreira física oferecida pelo ovissaco não podem fornecer defesa absoluta contra predadores.

18.
Braz. j. biol ; 76(3): 750-756, graf
Artigo em Inglês | LILACS | ID: lil-785036

RESUMO

Abstract This is the first description of a species of the genus Tanycarpa Förster (1862) for Brazil. Forty-eight specimens were collected in High Montane Dense Ombrophilous Forest area at National Park of Itatiaia, RJ, using four Malaise traps installed, respectively, at four different altitudes. This study is based on a description of two species of Tanycarpa from Colombia, Tanycarpa edithae and Tanycarpa sarmientoi, which are the only species of this genus recognized for the neotropics.


Resumo Esta é a primeira descrição de uma espécie do gênero Tanycarpa Förster (1862) para o Brasil. Foram coletados 48 espécimes em uma área de Floresta Ombrófila Densa Alto Montana do Parque Nacional do Itatiaia, RJ, com o uso de quatro armadilhas Malaise instaladas, respectivamente, em quatro altitudes diferentes. Este trabalho foi baseado na descrição de duas espécies de Tanycarpa da Colômbia, Tanycarpa edithae e Tanycarpa sarimentoi, as únicas espécies desse gênero reconhecidas para a região Neotropical.


Assuntos
Animais , Himenópteros/classificação , Brasil , Florestas , Altitude , Parques Recreativos
19.
Braz J Biol ; 76(3): 750-6, 2016 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-27097099

RESUMO

This is the first description of a species of the genus Tanycarpa Förster (1862) for Brazil. Forty-eight specimens were collected in High Montane Dense Ombrophilous Forest area at National Park of Itatiaia, RJ, using four Malaise traps installed, respectively, at four different altitudes. This study is based on a description of two species of Tanycarpa from Colombia, Tanycarpa edithae and Tanycarpa sarmientoi, which are the only species of this genus recognized for the neotropics.


Assuntos
Himenópteros/classificação , Altitude , Animais , Brasil , Florestas , Parques Recreativos
20.
Oncogene ; 35(13): 1619-31, 2016 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-26189796

RESUMO

E-cadherin is a central molecule in the process of gastric carcinogenesis and its posttranslational modifications by N-glycosylation have been described to induce a deleterious effect on cell adhesion associated with tumor cell invasion. However, the role that site-specific glycosylation of E-cadherin has in its defective function in gastric cancer cells needs to be determined. Using transgenic mice models and human clinical samples, we demonstrated that N-acetylglucosaminyltransferase V (GnT-V)-mediated glycosylation causes an abnormal pattern of E-cadherin expression in the gastric mucosa. In vitro models further indicated that, among the four potential N-glycosylation sites of E-cadherin, Asn-554 is the key site that is selectively modified with ß1,6 GlcNAc-branched N-glycans catalyzed by GnT-V. This aberrant glycan modification on this specific asparagine site of E-cadherin was demonstrated to affect its critical functions in gastric cancer cells by affecting E-cadherin cellular localization, cis-dimer formation, molecular assembly and stability of the adherens junctions and cell-cell aggregation, which was further observed in human gastric carcinomas. Interestingly, manipulating this site-specific glycosylation, by preventing Asn-554 from receiving the deleterious branched structures, either by a mutation or by silencing GnT-V, resulted in a protective effect on E-cadherin, precluding its functional dysregulation and contributing to tumor suppression.


Assuntos
Caderinas/metabolismo , N-Acetilglucosaminiltransferases/metabolismo , Neoplasias Gástricas/metabolismo , Sequência de Aminoácidos , Animais , Asparagina/genética , Caderinas/química , Caderinas/genética , Caderinas/fisiologia , Domínio Catalítico/genética , Linhagem Celular Tumoral , Cães , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patologia , Glicosilação , Células HT29 , Humanos , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , N-Acetilglucosaminiltransferases/antagonistas & inibidores , N-Acetilglucosaminiltransferases/genética , Homologia de Sequência de Aminoácidos , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia
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