Carly
Samera
Sponsor: Satoshi Namekawa, Ph.D. Microbiology & Molec Genetics Meiosis is a highly regulated process that must be restricted to germ cells to prevent genomic instability. The molecular mechanisms that prevent premature or inappropriate meiotic entry remain incompletely understood today. MAX is a transcriptional factor known to suppress meiotic gene expression in embryonic stem cells, but its role in the male germline remains unclear. To investigate whether MAX regulates meiosis initiation in germ cells, we analyzed a MAX knockout mouse model. Even after loss of MAX, spermatogenesis took place and sperm were produced; however, the number of sperm counts decreased, and seminiferous tubules showed a size reduction which hints towards defect in germ cell differentiation. Because reduced sperm output suggests disruption at a specific stage of germ cell development, we hypothesize that loss of MAX affects early meiotic progression, particularly during meiotic prophase I. Current work focuses on defining the specific defects in meiotic prophase I caused by loss of MAX, with the goal of focusing on how improper meiotic regulation contributes to reduced sperm output. Molecular Mechanisms Driving Organ Specific Regeneration in Pomacea canaliculata
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Carly Samera
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The golden apple snail is a novel model for sensory organ regeneration, namely eyes and tentacles. After eye amputation, the wound heals, cell proliferation increases, and eye-specific structures develop; however the molecular mechanisms driving eye-specific regeneration remain unknown. I hypothesize that an initial, generic injury-induced response triggering wound-healing and cell proliferation is followed by an organ-specific regeneration program. My goal is to compare tentacle and eye regeneration to determine when regeneration becomes organ- specific. I developed a timeline of tentacle regeneration, using morphological staining. While all tentacle-specific components appear by 9 days post-amputation (dpa), immunofluorescent staining for the mitotic marker Phosphorylated Histone 3 (H3P) demonstrates that dividing cells are still present at 9 dpa, suggesting that complete growth takes longer. Additionally, I observed two waves of intense cell proliferation: one at 8 hours post-amputation at the injury site and one at 3 dpa with H3P+ cells homogeneously dispersed throughout the tissue, possibly supporting my two-phase regeneration hypothesis. This dataset enables stage-matched molecular comparisons of tentacle and eye regeneration using in situ hybridization and qPCR to evaluate the expression dynamic of candidate genes. Overall, my project will identify the factors orchestrating organ-specific regeneration in apple snails, offering novel insights for regenerative medicine. Too Close to Home: A Study of Environmental Racism in Antioch, CA Maris Samsel
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UC Davis / Molecular & Cellular Bio / 2026
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Carly Samera