Presentation Title

Shifting Thermal Limits during Drosophila Embryonic Development

Abstract

Environmental temperature is in constant flux, and can pose extreme environmental changes which organisms must be able to cope with in order to survive. Response to changing temperature is particularly difficult for immobile organisms, which cannot escape poor conditions and thus must rely on a cellular response, upregulating protective and essential genes while downregulating energetically costly ones. In the fruit fly Drosophila melanogaster, early embryonic development may be particularly sensitive to temperature, as embryos at this stage are still developing necessary transcriptional machinery. As embryonic development progresses and the embryo becomes more transcriptionally active, however, they may have improved responses to extreme heat and cold. To test whether tolerance of temperature extremes improves across development, survival of 45-minute heat or cold shock temperatures at increasing/decreasing increments were conducted at six or eighteen hours of development, in order to estimate the temperature extreme at which half of embryos fail to hatch (LT50) for each developmental timepoint. Overall, the younger embryos were less tolerant of temperature extremes, with an LT50 of 39oC for heat shocks and -6oC for cold shocks. The more developed eighteen-hour embryos had a higher LT50 score at the hot end of 41.5oC, and a lower LT50 in response to cold, at -8oC. These data support the hypothesis that more developed, and more transcriptionally active, Drosophila embryos are better equipped to face temperature extremes.

Primary Faculty Mentor Name

Sara Helms-Cahan

Status

Undergraduate

Student College

College of Arts and Sciences

Program/Major

Biological Science

Primary Research Category

Biological Sciences

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Shifting Thermal Limits during Drosophila Embryonic Development

Environmental temperature is in constant flux, and can pose extreme environmental changes which organisms must be able to cope with in order to survive. Response to changing temperature is particularly difficult for immobile organisms, which cannot escape poor conditions and thus must rely on a cellular response, upregulating protective and essential genes while downregulating energetically costly ones. In the fruit fly Drosophila melanogaster, early embryonic development may be particularly sensitive to temperature, as embryos at this stage are still developing necessary transcriptional machinery. As embryonic development progresses and the embryo becomes more transcriptionally active, however, they may have improved responses to extreme heat and cold. To test whether tolerance of temperature extremes improves across development, survival of 45-minute heat or cold shock temperatures at increasing/decreasing increments were conducted at six or eighteen hours of development, in order to estimate the temperature extreme at which half of embryos fail to hatch (LT50) for each developmental timepoint. Overall, the younger embryos were less tolerant of temperature extremes, with an LT50 of 39oC for heat shocks and -6oC for cold shocks. The more developed eighteen-hour embryos had a higher LT50 score at the hot end of 41.5oC, and a lower LT50 in response to cold, at -8oC. These data support the hypothesis that more developed, and more transcriptionally active, Drosophila embryos are better equipped to face temperature extremes.