Graduate Students Mini-Symposium II 2022

Program:

16:00 Ismath Sadhir, AG Murray
"A mechanistic understanding of chromosome organization in E. coli"

In E. coli following replication, the duplicated Ori region of the chromosome move to the quarter positions. In the first part of my study we attempted to find the sequence identity that marks Ori for its positioning. In the second part of my study, we looked at the dynamics of terminus region of the E. coli chromosome. It is characterized by the presence of a protein known as MatP. It is not entirely known what events or factors influence the dynamics of MatP. We used a high-throughput single cell approach to delineate the events involved in MatP relocalization as well as to gain a better understanding of different chromosome reorganization events during a cell cycle.

16:30 Marco Herfurth, AG Sogaard-Andersen
"A noncanonical cytochrome c stimulates calcium binding by PilY1 for type IVa pili formation"

Type IVa pili (T4aP) are versatile bacterial cell surface structures that undergo extension/adhesion/retraction cycles powered by the cell envelope-spanning T4aP machine. In this machine, a complex composed of four minor pilins and PilY1 primes T4aP extension and is also present at the pilus tip mediating adhesion. Similar to many other bacteria, Myxococcus xanthus contains multiple minor pilins/PilY1 sets that are incompletely understood. Here, we report that minor pilins and PilY1 (PilY1.1) of cluster_1 form priming and tip complexes contingent on a noncanonical cytochrome c (TfcP) and calcium. Further, we provide evidence that cluster_1 employs TfcP to overcome calcium limitations and thereby broadens the range of environmental conditions at which cluster_1 can function.

17:00 Xin Li, RG Liesack
"Methanogenic community dynamics in Philippine rice field soil: a metagenomic and metatranscriptomic analysis"

Methanogenesis is the final step in anaerobic decomposition of biopolymers. The anaerobic food chain involves various functional guilds of bacteria and archaea, finally yielding methane and carbon dioxide. Rice field soils are a major anthropogenic source of methane, but particularly the late responses of methanogenic communities in rice field soils to the addition of complex carbon are not yet well studied. Here, we used a combination of metabolite measurements, quantitative real-time PCR and RT-PCR of particular bio-markers, and meta-omics (metatranscriptomics and metagenomics) to unravel the structural and functional responses of the methanogenic community in Philippine paddy soil to a long-term anoxic incubation period.