نتایج جستجو برای: embryonic diapause
تعداد نتایج: 82098 فیلتر نتایج به سال:
Male and female embryonic stem (ES) cell lines were derived from the area pellucidae of Stage X (EG&K) chicken embryos. These ES cell lines were grown in culture for extended periods of time and the majority of the cells retained a diploid karyotype. When reintroduced into Stage VI-X (EG&K) recipient embryos, the cES cells were able to contribute to all somatic tissues. By combining irradiation...
Seasonal environments present fundamental physiological challenges to a wide range of insects. Many temperate insects surmount the exigencies of winter by undergoing photoperiodic diapause, in which photoperiod provides a token cue that initiates an alternative developmental programme leading to dormancy. Pre-diapause is a crucial preparatory phase of this process, preceding developmental arres...
Diapause, a strategy to endure unfavourable conditions (e.g. cold winters) is commonly found in ectothermic organisms and is characterized by an arrest of development and reproduction, a reduction of metabolic rate, and an increased resistance to adversity. Diapause, in addition to adaptations for surviving low winter temperatures, significantly influences phenology, voltinism and ultimately po...
Some organisms can adapt to seasonal and other environmental challenges by entering a state of dormancy, diapause. Thus, insects exposed to decreased temperature and short photoperiod enter a state of arrested development, lowered metabolism, and increased stress resistance. Drosophila melanogaster females can enter a shallow reproductive diapause in the adult stage, which drastically reduces o...
The beet webworm, Loxostege sticticalis (L.) (Lepidoptera: Pyralidae), uses both diapause and migration as life history strategies. To determine the role of diapause plays in the population dynamics of L. sticticalis, the reproductive and flight potentials of adults originating from diapause and nondiapause larvae were investigated under controlled laboratory conditions. Preoviposition period,...
Adults of the cabbage beetle Colaphellus bowringi display a summer diapause in response to the exposure of their larvae to long photoperiods. In the present study, the inheritance of the photoperiodic response controlling summer diapause in C. bowringi by crossing a high diapause strain (D strain) with a laboratory selected nondiapause strain (N strain) was investigated under different photoper...
Life cycle delays are beneficial for opportunistic species encountering suboptimal environments. Many animals display a programmed arrest of development (diapause) at some stage(s) of their development, and the diapause state may or may not be associated with some degree of metabolic depression. In this review, we will evaluate current advancements in our understanding of the mechanisms respons...
Mouse embryonic stem cells (ESCs) are maintained in a naive ground state of pluripotency in the presence of MEK and GSK3 inhibitors. Here, we show that ground-state ESCs express low Myc levels. Deletion of both c-myc and N-myc (dKO) or pharmacological inhibition of Myc activity strongly decreases transcription, splicing, and protein synthesis, leading to proliferation arrest. This process is re...
Diapause, a programmed developmental arrest, is common in insects, enabling them to survive adverse seasons. It is well established that pupal diapause is regulated by ecdysteroids secreted by the prothoracic glands (PGs), with cessation of ecdysteroid secretion after pupal ecdysis leading to pupal diapause. A major factor regulating the gland activity is prothoracicotropic hormone (PTTH) secre...
In Drosophila melanogaster, exposure of females to low temperature and shortened photoperiod can induce the expression of reproductive quiescence or diapause. Diapause expression is highly variable within and among natural populations and has significant effects on life-history profiles, including patterns of longevity, fecundity, and stress resistance. We hypothesized that if diapause expressi...
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