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Please join us on Wednesday, March 5, at 4 pm in Room 2-190 for the C.C. Mei Distinguished Speaker Series with Dr. Trent Northen.Abstract Title: The Chemical Underground: Are Rhizosphere Microbes Hooked on Root Exudates?Abstract:Plants release a large fraction of the carbon they fix into the soil surrounding roots (the rhizosphere), shaping soil microbial communities to support plant health and productivity. Understanding rhizosphere processes is critical for sustainable agriculture and managing soil carbon cycling. However, these interactions remain poorly understood due to the inherent complexity and inaccessibility of these ecosystems. Progress has been further hindered by the lack of standard, replicable experimental systems, making it difficult for scientists to build on each other’s findings.In this talk, I will describe our approach to constructing fabricated rhizosphere ecosystems and share results from the first multilaboratory microbiome reproducibility study. Additionally, I will highlight recent discoveries from our work, including the unexpected exudation of dopamine—a key human neurotransmitter—by plant roots, and discuss the potential role of catecholamines in directing rhizosphere microbial community assembly.Bio:Dr. Trent Northen is Deputy Division Director and a Senior Scientist within the Environmental Genomics and Systems Biology Division at Berkeley Lab. His laboratory focuses on understanding the role of exogenous small molecule metabolites in mediating microbial interactions with other microbes and plant hosts and how these processes impact soil carbon cycling. A long-term goal of the Northen lab is to help harness plants and microbes for sustainable agriculture—including to restore soil carbon and improve soil health. Towards these goals the Northen lab has developed a range of metabolomic, cheminformatic, and bioinformatic capabilities for metabolite identification and analysis. Dr. Northen has also championed the development of fabricated ecosystems spanning scales and complexity.The C.C. Mei Distinguished Speaker Series was founded and has been organized in honor of Prof. Chiang C. Mei. It aims to provide a vibrant forum for highly distinguished speakers, from around the world, to share their research with the CEE, MIT, and local Boston community.

Speaker: Hao Peng (MIT)

Date: Wednesday, March 5, 2025 Location: 46-3002 (Singleton Auditorium)Speaker: Haitham Amal, PhD Affiliation: Associate Professor (Tenured), The School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem; Visiting Professor, Boston Children’s Hospital, Harvard Medical School, Harvard UniversityHost: Dr. Alan JasanoffTalk title: The NO Answer for Autism Spectrum DisorderAbstract: Autism spectrum disorder (ASD) is a neurodevelopmental disorder that shares core behavioral deficits. A few molecular mechanisms have been identified in ASD when most of the studies focus on a single pathway/target. To date, no effective single-drug treatment has been found for ASD, which raises the need for new drug targets. We hypothesize that multi-molecular pathways parallelly may lead to synaptic/neuronal dysfunctions and eventually to ASD phenotype. Our multi-proteomic approach using clinical and mouse model samples identified three novel potential targets possibly orchestrating in ASD: (1) de novo S-nitrosylation (NO-mediated protein modification) of the TSC2 protein. In this talk, I will focus on the role of NO (nitric oxide) in ASD. (2) Upregulation of Gephyrin phosphorylation at specific sites, which affects synaptic plasticity and functions. (3) An abnormal upregulation of the catalytic subunit of the mitochondrial ATP synthase, which may affect the integrity of the inner mitochondrial membrane. Here, we used ASD human plasma samples, human induced pluripotent stem cells (hiPSCs), and mouse models to perform a comprehensive study of the mechanisms underlying ASD pathology. The three-way pathological mechanisms were investigated using a state-of-the-art multi-proteomics platform coupled with sophisticated systems biology analyses to filter out ASD-relevant molecular changes. Pharmacological and CRISPR/Cas9 tools were used to validate the targets and explore the molecular and synaptic features following interventions. Three mouse models of ASD (Shank3, Cntnap2, and Nlgn3) were used to evaluate the behavioral outcomes of the pharmacological treatment. This talk will focus on deciphering unknown multi-way molecular mechanisms underlying ASD pathology that may uncover novel drug targets for ASD.

Speaker: Serena An (MIT) & Katherine Tung (Harvard)Title: Newton polytopes of dual Schubert polynomialsAbstract: The M-convexity of dual Schubert polynomials was first proven by Huh, Matherne, Mészáros, and St. Dizier in 2022. We give a full characterization of the supports of dual Schubert polynomials, which yields an elementary alternative proof of the M-convexity result, and furthermore strengthens it by explicitly characterizing the vertices of their Newton polytopes combinatorially. Using this characterization, we give a polynomial-time algorithm to determine if a coefficient of a dual Schubert polynomial is zero, analogous to a result of Adve, Robichaux, and Yong for Schubert polynomials. This is a joint work with Yuchong Zhang, and there is a companion paper titled “Postnikov–Stanley Polynomials are Lorentzian.”