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Biology Postdoc Minisymposium II

J. Cerchiara, S. Conway, A. Leydon
University of Washington, Department of Biology
Seminar date:
Monday, November 20, 2017 - 11:45
HCK 132

Name: Jack Cerchiara, PhD

Title: Telomere maintenance and corticosterone in Magellanic penguins

Abstract: Telomeres shorten with age in most species, and may affect adult survival. Corticosterone, and stress, has been linked to telomere shortening in other species. Magellanic penguins are a particularly good model organism as they are an unusually long-lived species, exceeding their mass-adjusted predicted lifespan by 26%. Contrary to our hypothesis, we found adults aged 5 years to over 24 years of age had similar telomere lengths. Neither telomere length, nor the rate at which the telomeres changed over these 3 years, correlated with breeding frequency or investment. Corticosterone was not correlated with telomere length in adults and suggests that low basal corticosterone may play a role in the telomere maintenance observed. Corticosterone also declined during the breeding season and was positively correlated with the age of adult penguins. Our results demonstrate that telomere maintenance may be a component of longevity even with increased reproductive effort, investment, and basal corticosterone.

Lab Information: BERG/Boersma Lab

Intro:  Jack obtained his PhD in Dee Boersma's lab here at the University of Washington studying the relationship between telomeres, aging and reproduction in very long lived Magellanic penguins. Jack continued as a PostDoc in Dr. Boersma’s Lab studying baseline corticosterone and telomeres in wild and captive Spheniscus penguins. Jack recently joined the Biology Education Research Group as a PostDoc using machine learning to assess student learning of technical physiology.

Name: Stephanie Conway

Title: Using the model fern Ceratopteris richardii to reconstruct the ancestral role of a flowering  gene.

Abstract: LEAFY (LFY) is a transcription factor with an important role in floral meristem identity in angiosperms. LFY orthologs are found across non-flowering land plants suggesting an important ancestral function beyond flower development. Recent stable transgenesis of the model fern Ceratopteris richardii presents a golden opportunity to examine LFY function in this early-diverging vascular plant. Preliminary experiments on validated loss-of-function transgenic lines suggest that CrLFY plays a role in the early germination and growth of the gametophyte, as well as a later role in the sporophyte, possibly in the establishment of its shoot meristem, and in the development of the dissected leaf morphology. Based on our results, our working hypothesis is that LFY’s floral meristem identity function in angiosperms was recruited from a broader meristematic role in earlier vascular plants.

Lab information: Di Stilio Lab

Name: Alexander Leydon

Title: Hacking phytohormone signaling to reprogram plant development

Abstract: Maintaining food security requires the development of genetic tools to re-design morphological traits of crop plants for greater productivity and robustness to climatic variability. Plant hormone circuitry is an obvious target for engineering as it regulates most developmental programs. The Nemhauser lab has developed a set of synthetic and modular hormone activated Cas9-based repressors (HACRs) that respond to phytohormones. HACRs can be used to reprogram development to improve yield-associated traits under the control of the phytohormone gibberellic acid (GA). We have programmed GA-HACRs to target GA biosynthesis in order to reduce the total output of the GA hormone-signaling pathway. To create predictions about the effects of programmed GA-HACRs we implemented a mathematical model of GA production and signaling with and without GA-HACRs. Tuning GA signaling by GA-HACR integration into the endogenous hormone pathway allows specific targeting of agriculturally relevant GA-responses such as cell elongation, flowering time, and male fertility. 
Lab information: Nemhauser Lab

Intro: Alex obtained his PhD in Mark Johnson’s lab at Brown University studying the transcriptional network controlling pollen tube development, gametophyte cell-signaling and sperm release. He joined the Nemhauser lab in 2017 to study how phytohormone signaling converges on nuclear gene expression, and how synthetic biology can integrate into endogenous transcriptional networks.

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