“…In A. mellifera queens, the regenerative cells in the nest periphery are narrowed and tall, whereas the central cells are globular, similar to those described in other bees [41,42], ants [43] and Hemiptera [27]. In adult insects, it has been claimed that the regenerative cells do not divide, and when they onset to differentiate push the digestive cells above them, which are released into the midgut lumen [44]. When these differentiating cells reach the midgut of the lumen, they are columnar-shaped and develop the brush border [18,[44][45][46].…”
Section: Discussionsupporting
confidence: 63%
“…In adult insects, it has been claimed that the regenerative cells do not divide, and when they onset to differentiate push the digestive cells above them, which are released into the midgut lumen [44]. When these differentiating cells reach the midgut of the lumen, they are columnar-shaped and develop the brush border [18,[44][45][46].…”
The honey bee Apis mellifera is a plant-pollinator that produces commercial products. It has female castes with workers performing tasks in the colonies and a queen, it has the longest lifespan, in charge of reproduction. This bee undergoes a population decline worldwide. Therefore, it is important to understand how aging affects the digestive tract of this insect. In the midgut, regenerative cells are organized in nests replacing the dead cells. This study verified the hypothesis that the number of regenerative cells decreases as A. mellifera queen ages. The midgut was evaluated in queens at the age of four days and eight, 11 and 25 months. The midgut of 11-and 25-month-old queens presented signs of epithelial disorganization in comparison with younger queens. The number of regenerative cell nests in the midgut decreases according to the age of the queen, but the number of cells per nest is similar. The decreased number of regenerative cell nests reveals a potential loss in the amount of these cells available for the renewal of the midgut epithelium. The absence of variations in the number of regenerative cells per nest according to the queen age indicates that these cells do not undergo proliferation before the differentiation.
“…In A. mellifera queens, the regenerative cells in the nest periphery are narrowed and tall, whereas the central cells are globular, similar to those described in other bees [41,42], ants [43] and Hemiptera [27]. In adult insects, it has been claimed that the regenerative cells do not divide, and when they onset to differentiate push the digestive cells above them, which are released into the midgut lumen [44]. When these differentiating cells reach the midgut of the lumen, they are columnar-shaped and develop the brush border [18,[44][45][46].…”
Section: Discussionsupporting
confidence: 63%
“…In adult insects, it has been claimed that the regenerative cells do not divide, and when they onset to differentiate push the digestive cells above them, which are released into the midgut lumen [44]. When these differentiating cells reach the midgut of the lumen, they are columnar-shaped and develop the brush border [18,[44][45][46].…”
The honey bee Apis mellifera is a plant-pollinator that produces commercial products. It has female castes with workers performing tasks in the colonies and a queen, it has the longest lifespan, in charge of reproduction. This bee undergoes a population decline worldwide. Therefore, it is important to understand how aging affects the digestive tract of this insect. In the midgut, regenerative cells are organized in nests replacing the dead cells. This study verified the hypothesis that the number of regenerative cells decreases as A. mellifera queen ages. The midgut was evaluated in queens at the age of four days and eight, 11 and 25 months. The midgut of 11-and 25-month-old queens presented signs of epithelial disorganization in comparison with younger queens. The number of regenerative cell nests in the midgut decreases according to the age of the queen, but the number of cells per nest is similar. The decreased number of regenerative cell nests reveals a potential loss in the amount of these cells available for the renewal of the midgut epithelium. The absence of variations in the number of regenerative cells per nest according to the queen age indicates that these cells do not undergo proliferation before the differentiation.
“…As in other insects, it is common the occurrence of a huge amount of nests of regenerative cells at the midgut of N. rotundatus; in this species, the number of mitotic figures was expressive inside the nests. Expressive mitotic activity was also observed in other species of termite (Cruz-Landim & Costa-Leonardo 1996).…”
Section: Discussionmentioning
confidence: 53%
“…Mitotic division of regenerative cells in mature insects happens in few groups such Orthoptera (Zudaire et al 2004) and Heteroptera (Endo1983). In Hymenoptera, the mitosis of regenerative cells was observed in queens (França et al 2006), but not in workers Cruz-Landim & Costa-Leonardo 1996). According to Cruz-Landim & Costa-Leonardo (1996), the occurrence of a considerable number mitosis at the midgut termite workers not must be considered an exception, as this caste (in Isoptera) is not comprised by mature individualswhich are the flying forms -but by immature ones.…”
“…A observação de células em picnose nuclear indica a possibilidade do mecanismo de desintoxicação, pois esta é uma etapa no processo de morte celular programada, na qual há a condensação da cromatina nuclear (Donan & Cotter, 2008). A eliminação de células do intestino médio, em abelhas saudáveis, é uma estratégia natural para a manutenção do epitélio, na qual células digestivas danificadas pelos estresses químicos e físicos do processo de digestão, são eliminadas para o lúmen do órgão, sendo substituídas por novas células digestivas a partir da diferenciação de células regenerativas presentes em ninhos na região basal do epitélio (Cruz-Landim & Costa-Leonardo, 1996).…”
A abelha Apis mellifera desempenha papel como polinizadora de plantas nativas e cultivadas, atuando no aumento da produtividade de diversas culturas, na preservação da flora e na produção de sementes florestais. Um fenômeno que vem preocupando os pesquisadores e agricultores é o declínio da população de abelhas, incluindo A. mellifera que apresentam o Distúrbio do Colapso de Colônias (CCD), tendo como uma das possíveis causas o uso excessivo de agrotóxicos nas plantações. O teflubenzurom é um inseticida do grupo benzoiluréia, que inibe a síntese de quitina, um dos principais componentes do tegumento do inseto na formação do exoesqueleto, entretanto sua ação em órgãos não alvos de insetos é ainda desconhecida. O intestino médio é a principal região do trato digestório com função de secreção de enzimas digestivas e absorção de nutrientes, estando exposto à ação de pesticidas ingeridos com o alimento. O objetivo foi avaliar os efeitos tóxicos e histopatológicos no intestino médio de operárias adultas de A. mellifera causados pela exposição oral crônica ao teflubenzurom. Operárias expostas ao teflubenzurom por oito dias tem alta mortalidade, apresentando 13% de sobrevivência em relação ao grupo controle. Abelhas tratadas com teflubenzurom apresentam o epitélio do intestino médio com excessiva vacuolização, esferocristais, secreção apócrina, picnose nuclear, liberação de fragmentos celulares para o lúmen do órgão, perda do contato celular, danos nos ninhos de células regenerativas e na matriz peritrófica. Os resultados indicam que o inseticida inibidor da síntese de quitina, teflubenzurom, é tóxico para A. mellifera após exposição oral crônica em concentração campo-realista, embora seja classificado como pouco ou não tóxico para insetos adultos e não-alvos. Palavras-chave: Inseticida. Abelha. Histopatologia.
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