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Biology

Dissertations and Theses

Diapause

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Full-Text Articles in Life Sciences

Connecting Environment And Phenotype: Deciphering Mechanisms Of Diapause Entry And Exit In The Annual Killifish Austrofundulus Limnaeus, Erin Monica Davis Apr 2021

Connecting Environment And Phenotype: Deciphering Mechanisms Of Diapause Entry And Exit In The Annual Killifish Austrofundulus Limnaeus, Erin Monica Davis

Dissertations and Theses

Embryonic development is complex, dynamic, and dependent on environmental factors. Mechanisms of sensing and integrating environmental stimuli are diverse, and understanding these mechanisms in extant species can elucidate how complex phenotypes emerge from genomic information expressed in an environmental context. In Austrofundulus limnaeus, an annual killifish with alternative developmental trajectories, light and temperature are vital factors that determine if an embryo will enter a state of diapause. We hypothesize that embryos of A. limnaeus use the vitamin D3 signaling pathway as a vehicle to incorporate these ecological signals into their developmental programing. Here we provide evidence of …


No Oxygen, No Water: The Unique Physiology Of Annual Killifish Embryos Across Development, Daniel Erik Zajic Jul 2020

No Oxygen, No Water: The Unique Physiology Of Annual Killifish Embryos Across Development, Daniel Erik Zajic

Dissertations and Theses

For most vertebrates, an abundance of oxygen is necessary for the production of ATP and the maintenance of cellular homeostasis. The absence of oxygen, even for brief periods, quickly leads to ATP depletion which can lead to irreparable damages to sensitive organs, such as the brain and heart. However, certain vertebrates demonstrate an extraordinary ability to thrive and recover fully from periods of no oxygen (anoxia). The annual killifish (Austrofundulus limnaeus) lives in ephemeral ponds in the Maracaibo basin of Venezuela and their embryos have the remarkable ability to not only survive anoxic periods for months, but also …


Transcriptomic Regulation Of Alternative Phenotypic Trajectories In Embryos Of The Annual Killifish Austrofundulus Limnaeus, Amie L. Romney Nov 2017

Transcriptomic Regulation Of Alternative Phenotypic Trajectories In Embryos Of The Annual Killifish Austrofundulus Limnaeus, Amie L. Romney

Dissertations and Theses

The Annual Killifish, Austrofundulus limnaeus, survives the seasonal drying of their pond habitat in the form of embryos entering diapause midway through development. The diapause trajectory is one of two developmental phenotypes. Alternatively, individuals can "escape" entry into diapause and develop continuously until hatching. The alternative phenotypes of A. limnaeus are a form of developmental plasticity that provides this species with a physiological adaption for surviving stressful environments. The developmental trajectory of an embryo is not distinguishable morphologically upon fertilization and phenotype is believed to be influenced by maternal provisioning within the egg based on observations of offspring phenotype …


Developmental Mechanisms That Support Genome Stability And Embryonic Survival In Stress-Tolerant Embryos Of The Annual Killifish Austrofundulus Limnaeus, Josiah Tad Wagner Sep 2015

Developmental Mechanisms That Support Genome Stability And Embryonic Survival In Stress-Tolerant Embryos Of The Annual Killifish Austrofundulus Limnaeus, Josiah Tad Wagner

Dissertations and Theses

In order to complete their life cycles, vertebrates require oxygen and water. However, environments are not always forgiving when it comes to constantly providing these basic needs for vertebrate life. The annual killifish Austrofundulus limnaeus is possibly the most well described extremophile vertebrate and its embryos have been shown to tolerate extremes in oxygen, salinity, and water availability. This phenotype is likely a result of the annual killifish life history, which includes periods of temporary habitat desiccation and oxygen deprivation, and requires the production of stress-tolerant embryos that depress metabolism in a state of suspended animation, known as diapause. Over …