DATE: Monday, December 10, 2018
TIME: 11:00 AM - 12:30 PM
LOCATION:Auditorium between Bldg 2&3 - Level 0 - Room 0215
Peter H. Quail UC Berkeley/ARS Plant Gene Expression Center, Albany CA 94710, USA Peter Quail is Professor of Plant and Microbial Biology, University of California, Berkeley, and Research Director, of the ARS/UCB Plant Gene Expression Center, Albany, California. Bio:Professor Quail is a recipient of the American Society of Photobiologists Research Award, the LI-COR Award for Distinguished Contributions to Photochemistry/Photobiology, Corresponding Membership of the Australian Society of Plant Physiologists, recipient of ISI award for top 15 most highly cited authors in the Plant & Animal Science discipline, Fellow of the American Association for the Advancement of Science, recipient of the Stephen Hales Award from the American Society of Plant Biologists and a Member of the U.S. National Academy of Sciences. His research is focused on defining the molecular mechanism by which the phytochrome (phy) family of plant sensory photoreceptors controls gene expression, and thereby plant growth and development, in response to informational light-signals from the environment. His laboratory has provided evidence that the signaling mechanism involves rapid, direct, intranuclear interaction of the light-activated photoreceptor molecule with a sub-family of basic helix-loop-helix (bHLH) transcription factors (called PIFs), with resultant induction of phosphorylation and polyubiqitination of the PIF proteins, as a prelude to degradation of the bHLH factors by the ubiquitin-proteasome system, and consequent genome-wide gene-expression changes. His research program has identified the protein kinases and E3 ubiquitin ligases involved and the genome-wide gene-set that are direct targets of transcriptional regulation by the PIFs. Abstract:Our research interests are in defining the mechanisms by which light signals are perceived and transduced by the phytochrome (phy)-PIF module to Direct-Target Genes (DTGs), focused specifically on the two sequential interfaces (a) between the phy and PIF proteins, and (b) between the PIFs and their DTGs. Existing data suggest that these components engage in dynamic multimolecular complexes comprised variously of (a) protein kinases (that include PPKs (Photoregulatory Protein Kinases)) and E3 ubiquitin ligases (including LRBs, EBFs and COP1-SPA), that sequentially phosphorylate and ubiquitinate the PIFs to regulate their abundance, and (b) a diversity of other interacting components that modulate the intrinsic transcriptional activation activity of the PIFs (including the core clock protein, TOC1). The data suggest yet greater complexity in the system, including potential mechanistic differences among the individual PIFs, as yet unidentified factors that may contribute to the signaling process, and trans-factors that may modulate PIF transcriptional regulatory capacity in situ at the genome interface, independently of the level of promoter occupancy. Our current efforts, using a combination of mass-spectrometric, biochemical and molecular genetic approaches to explore these possibilities will be described.
DATE: Tuesday, December 11, 2018
TIME: 03:00 PM - 04:00 PM
LOCATION:Building 2 - Level 5 - Room 5209
Abstract: Interorganellar communication is an evolutionary necessity for maintenance of cellular homoeostasis in response to prevailing environment that, in part, is exquisitely controlled via retrograde-signaling pathways.We have identified a novel stress-specific plastidial retrograde signalling metabolite, methylerythritol cyclodiphosphate (MEcPP), previously known solely as an intermediate in the isoprenoid biosynthetic pathway. The additional function of MEcPP as a stress sensor and a coordinator of transcriptional and post transcriptional regulation of key stress-responsive nuclear genes, has unraveled the central role of this metabolite in cellular functions in response to a wide range of environmental and developmental cues.To identify the underlying molecular mechanism of the MEcPP-mediated stress responses, we have performed a multi-omics approach. These studies have led to the identification of a transcriptional hub activated by MEcPP, and have further established a previously unrecognized link between this plastidial retrograde signal and the transcriptional reprogramming of endoplasmic reticulum genes critical for readjustment of protein-folding capacity in stressed cells. Lastly, we have gained an insight into the molecular mechanism by which MEcPP regulates plant growth and development in response to stress.In brief we have advanced our understanding of how MEcPP reprograms a repertoire of intricate networks crucial for coordinating the physiological and metabolic processes required for stress- induced developmental responses and stress adaptation. Bio:Prof. Katayoon DeheshInstitute of Integrative Genome Biology and Department of Botany and Plant Sciences UC Riverside, USAMain areas of research: Biosynthetic enzymes, fatty acids, molecular genetics, stress signalling pathways, interorganellar communication and cellular homeostasisK. Dehesh is a molecular biochemist working in the areas of plant stress responses, with a specific emphasis on the mechanisms regulating interorganellar communication required for cellular homoeostasis in response to prevailing environmental conditions.Academic and Professional Career2016- Director, Institute of Integrative Genome Biology, University of California (UC), Riverside, USA2016- Ernst and Helen Leibacher Endowed Chair, UC Riverside2011 - 2016 Endowed Chair of Paul Stumpf in Plant Biochemistry, UC Davis2009 - 2016 Chair of Designated Emphasis in Biotechnology, UC Davis2006 - 2009 Chair of plant biology graduate group, UC Davis2002- Full Professor, UC Davis2000 - 2002 Lipids program leader, Calgene Campus of Monsanto, USA2000 - 2002 Adjunct Professor, Plant Biology, UC Davis, USA1997 - 2000 Senior Research Scientist, Calgene Campus of Monsanto, USA1994 - 1997 Principle Research Scientist, Calgene, USA1989 - 1994 Researcher, Plant Gene Expression/ Department of Plant Biology, UC Berkeley1977 PhD, Plant Physiology, Sussex University, UK1973 Bachelor of Science, Pahlavi University, IranHonours and Awarded Memberships2017 Member of the German National Academy of Sciences Leopoldina2014 College of Biological Sciences (CBS) Teaching Award at UC Davis2013 Fellow of the American Association for the Advancement of Science (AAAS)2012 Honorary Professor, South West University, China2009 Excellence in Education Award, UC Davis2002 Monsanto Fellow1974 Iran National Award
TIME: 04:00 PM - 05:00 PM
LOCATION:Building 4 - Level 5 - Room 5209
PhD Advisor: Professor Peiying HongAbstract:The emergence and rapid spread of antimicrobial resistance (AMR) is a phenomenon that extends beyond clinical settings. AMR has been detected in multiple environmental compartments, including agricultural soils and water bodies impacted by wastewater discharges. The purpose of this research project was to evaluate what factors could influence the environmental persistence of antibiotic resistance genes (ARGs), as well as to identify potential strategies employed by human pathogens to survive in secondary environment outside the host. The first part of this dissertation describes the isolation and characterization of a multi-drug resistant and potentially pathogenic strain of Escherichia coli (Denoted as PI7), which was recovered from a municipal sewage network in Saudi Arabia. In the subsequent section we describe the decay kinetics of E. coli PI7 in microcosm experiments simulating biological treatment units of wastewater treatment plants. We identified that transition to dormancy is the main strategy prolonging the persistence of E. coli PI7 in the microcosm experiments. Additionally, we observed slower decay of E. coli PI7 and prolonged stability of extracellular DNA in anoxic/anaerobic conditions. In the last chapter of this thesis, the fate of extracellular DNA is further explored. Using as a model Acinetobacter baylyi ADP1, we describe the stimulation of natural transformation frequencies in the presence of chlorination disinfection byproducts (DBPs). Moreover, we provide insight on the molecular mechanism explaining the observed dose-response increase of natural transformation frequencies.Bio:In 2010 David Mantilla received his bachelors in microbiology from Los Andes University, Bogota - Colombia. He then relocated to KAUST to pursue a masters in environmental science and engineering. In 2013, he was enrolled as PhD student under the supervision of Dr Peiying Hong. David’s primary research interest and line of work focuses on the strategies for dispersal and persistence of antibiotic resistant pathogens in the environment.
DATE: Thursday, December 20, 2018
TIME: 11:00 AM - 12:00 PM
LOCATION:Building 2 - Level 5 - Room 5220
Abstract: The innate immune system forms an evolutionarily ancient line of defense against invading pathogens and endogenous danger signals. Within certain cells of innate immunity, including epithelial cells and macrophages, intricate molecular machineries named inflammasomes sense a wide array of stimuli to mount inflammatory responses. Inflammasomes are large multiprotein complex which play a key role in innate immunity by participating in the production of the pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18. Dysregulation in inflammasome signaling leads to a wide range of immune disorders such as allergies, Crohn’s disease and sepsis.
NLRP3 is the most extensively studied inflammasome sensor that responds to a broad spectrum of unrelated microbial stimuli and endogenous signals, uric acid crystals, extracellular ATP, including pore-forming toxins and potassium efflux. Recently identified NEK7 protein, a centrosomal protein member of NIMA-related kinases, is an essential mediator of NLRP3 activation and oligomerization downstream of potassium efflux. Cryo- electron microscopy (Cryo-EM) reconstruction of NLRP3 bound with NEK7 at 4.3 Å resolution reveals an earring-like structure of NLRP3 bound to NEK7. NEK7 C-lobe interacts with leucine-rich repeat (LRR), homology domain 2 (HD2) and Nucleotide- binding domain (NBD) of NLRP3. With the structure guided mutations and cellular experimental data combined with prior knowledge of activation mechanism of NLRs, we present a model of activation and oligomerization mechanism of NLRP3 implicated by NEK7.