2022 Symposium for Student Research, Scholarship, and Creative Activity

The study of bacteria has been an ongoing process for hundreds of years. While the field itself covers broad areas, one of the cornerstones is accurate and definitive classification of individual isolates. Through a polyphasic approach, including classical physiology and biochemical testing along with 16S rRNA gene analysis and genome sequencing, a vast number of bacteria have been officially identified, however, in spite of our best efforts, less than 1% of all bacteria have actually been properly taxonomically classified. Over the past several decades, the field of microbiology has made significant advances in the area of molecular analysis which have resulted in much more accurate classification methods. A polyphasic taxonomic study was carried out on strain TSed Te1T, isolated from sediment of a stream contaminated with acid mine drainage. Nearly complete 16S rRNA gene sequence homology related the strain to Gordonia, with 99.52 % and 99.36 % similarity to G. namibiensis and G. rubripertincta, respectively. Computation of average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) with the closest phylogenetic neighbor of TSed Te1T revealed genetic differences at the species level, further substantiated by differences in several physiological characteristics. The dominant fatty acids were C16:0, C18:1 w9c,, and 10 methyl C18:0, very characteristics of the genus Gordonia, as was the DNA G + C content of 67.6 mol %. This isolate was also resistant to very high levels of tellurite, selenite, and vanadate, a unique ability possessed by limited bacterial species. On the basis of results obtained, this bacterium was assigned to the genus Gordonia as a new species with the name Gordonia metalliredigo.

A typical cell cycle is characterized by a growth phase followed by DNA replication and then finally cell division, which produces genetically identical cells. Alternatively, in the process known as endoreduplication, cells grow, and DNA replication occurs, but the cell does not divide. In plants, CDC20 and CCS52 proteins control when a cell undergoes either mitosis or endoreduplication, respectively, via activating the anaphase promoting complex (APC). The APC then targets specific proteins called cyclins for degradation. This research project focuses on a potential third type of APC activator in soybean (Glycine max), Glyma.10G117000.1 or GLYMA10. GLYMA10 shares sequence similarities with CDC20 and CCS52 proteins such as a conserved C- box, MAD2-binding motif, IR tail, RVL motif, and WD40 domain, which indicates that the protein is capable of interacting with the APC, but there are also distinct differences between the proteins. To confirm that GLYMA10 is expressed, polymerase chain reaction (PCR) was used to amplify GLYMA10 from flower cDNA. The PCR product was cloned into a sequencing vector, which was then transformed into E. coli. The plasmid was sequenced confirming that GLYMA10 is expressed in flowers. Quantitative PCR (qPCR) was then used to analyze expression levels of GLYMA10 not only in flowers, but also in apical meristems, trifoliate leaves, unifoliate leaves, stems, roots, seeds, and new and old seed pods. Overall, GLYMA10 was not expressed in trifoliate leaves, unifoliate leaves, roots, or stem tissues and was only very weakly expressed in seeds, flowers and apical meristems. It was, however, very strongly expressed in new and old seed pods, with old seed pods showing the highest expression levels of GLYMA10. In the future, we will continue to study seed pods in an effort to understand the function of this protein.