BEGIN:VCALENDAR VERSION:2.0 PRODID:-//wp-events-plugin.com//7.2.2.1//EN TZID:Asia/Jerusalem X-WR-TIMEZONE:Asia/Jerusalem BEGIN:VEVENT UID:1342@biology.technion.ac.il DTSTART;TZID=Asia/Jerusalem:20251222T130000 DTEND;TZID=Asia/Jerusalem:20251222T140000 DTSTAMP:20251216T065203Z URL:https://biology.technion.ac.il/en/seminars/faculty-seminar-dr-jonathan -gropp-university-of-california-berkeley-ca-usa/ SUMMARY:Faculty Seminar-Dr. Jonathan Gropp (University of California\, Be rkeley\, CA\, USA) [No Categories] DESCRIPTION:Location: Faculty Of Biology Auditorium Dr. Jonathan Gropp \ n Affiliation: University of California\, Berkeley\, CA\, USA\n Host:Dr\, Maya Maor-Nof \n Dear Biology Students\, Postdocs\, and Faculty\,\n\n  \;\n\nNext week for our Faculty Seminar Series at 1:00 p.m. on Monday\, De cember 22nd\, we will have a talk by Dr. Jonathan Gropp of the Departmen t of Earth and Planetary Science\, University of California\, Berkeley\, C A\, USA. Dr. Jonathan Gropp will present a talk titled "Decoding microbia l methane production: from genes to ecosystems".\n\n \;\n\nTalk Abstra ct: \n\n \;\n\nMethanogenic archaea (methanogens) have the unique cap ability to couple methane (CH4) production with growth and energy conserva tion\, and they play a key role in the global carbon biogeochemical cycle. Despite this\, significant gaps remain in our understanding of their phys iology\, metabolism\, and ecology. This talk presents a platform for bridg ing this gap by using stable isotopes as probes to decode microbial methan e production from the gene to the ecosystem level.\n\nIn my work\, I study microbial methane metabolism using the stable isotopic ratios of carbon a nd hydrogen (13C/12C and 2H/1H) in methane\, which are widely used to tra ce methanogenic activity in natural environments. We have recently found t hat isotopic signatures of methane produced in laboratory cultures are dis tinct from those in natural environments. We have proposed that growth und er energy-limiting conditions increases enzyme reversibility\, thereby ind ucing isotopic exchange and altering isotopic signatures. To test this  “reversibility hypothesis\,” we used a genetically tractable methanoge nic strain modified via CRISPR-Cas9 to control the expression of methyl– coenzyme M reductase (MCR)\, a key enzyme in the pathway. Our results demo nstrate that MCR down-regulation decreases growth rates and alters the iso topic signature of the methane\, confirming that enzyme reversibility sets isotopic signatures under non-optimal growth conditions. We further found that temperature variations produce similar effects\, indicating that enz yme reversibility is prevalent during methanogenic growth\, especially und er conditions found in natural environments. These findings demonstrate th e utility of novel genome-editing techniques and stable-isotope probing as powerful tracers of biochemical processes in microbial metabolism and phy siology.\n\nFinally\, I will discuss future directions for my work\, using experimental and theoretical approaches\, including\, for example\, devel oping novel metabolic and isotopic biomarkers to track nitrogen fixation by methanogens. Nitrogen fixation first emerged in methanogens\, but their role in the nitrogen cycle remains unclear. I aim to elucidate this enigm a\, linking the carbon and nitrogen biogeochemical cycles. Such studies es tablish mechanistic frameworks to understand the fundamentals of microbial physiology and ecology\, paving the way for targeted strategies to mitiga te climate change and enhance renewable energy production.\n\n \;\n\nL ooking forward to seeing you!\nMaya LOCATION:Faculty Of Biology Auditorium END:VEVENT BEGIN:VTIMEZONE TZID:Asia/Jerusalem X-LIC-LOCATION:Asia/Jerusalem BEGIN:STANDARD DTSTART:20251026T010000 TZOFFSETFROM:+0300 TZOFFSETTO:+0200 TZNAME:IST END:STANDARD END:VTIMEZONE END:VCALENDAR