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Recent Publications and Presentations by IM Students and Faculty - July 2021

Below are recent publications and presentations by IM students, faculty, and affiliates. Would you like your research showcased? Send your paper to in time for the next edition!

Bold Indicates ISU faculty and affiliates 

^Indicates publications by IM students


1. ^Lambrecht N, ^Stevenson Z, Sheik C.S., Pronschinske M.A., Tong H, Swanner E.D. Candidatus Chlorobium masyteum', a novel photoferrotrophic green sulfur bacterium enriched from a ferruginous meromictic lake. Front Microbiol. 2021 Jul 09;

Abstract: Anoxygenic phototrophic bacteria can be important primary producers in some meromictic lakes. Green sulfur bacteria (GSB) have been detected in ferruginous lakes, with some evidence that they are photosynthesizing using Fe(II) as an electron donor (i.e., photoferrotrophy). However, some photoferrotrophic GSB can also utilize reduced sulfur compounds, complicating the interpretation of Fe-dependent photosynthetic primary productivity. An enrichment (BLA1) from meromictic ferruginous Brownie Lake, Minnesota, United States, contains an Fe(II)-oxidizing GSB and a metabolically flexible putative Fe(III)-reducing anaerobe. “Candidatus Chlorobium masyuteum” grows photoautotrophically with Fe(II) and possesses the putative Fe(II) oxidase-encoding cyc2 gene also known from oxygen-dependent Fe(II)-oxidizing bacteria. It lacks genes for oxidation of reduced sulfur compounds. Its genome encodes for hydrogenases and a reverse TCA cycle that may allow it to utilize H2 and acetate as electron donors, an inference supported by the abundance of this organism when the enrichment was supplied by these substrates and light. The anaerobe “Candidatus Pseudopelobacter ferreus” is in low abundance (∼1%) in BLA1 and is a putative Fe(III)-reducing bacterium from the Geobacterales ord. nov. While “Ca. C. masyuteum” is closely related to the photoferrotrophs C. ferroooxidans strain KoFox and C. phaeoferrooxidans strain KB01, it is unique at the genomic level. The main light-harvesting molecule was identified as bacteriochlorophyll c with accessory carotenoids of the chlorobactene series. BLA1 optimally oxidizes Fe(II) at a pH of 6.8, and the rate of Fe(II) oxidation was 0.63 ± 0.069 mmol day–1, comparable to other photoferrotrophic GSB cultures or enrichments. Investigation of BLA1 expands the genetic basis for phototrophic Fe(II) oxidation by GSB and highlights the role these organisms may play in Fe(II) oxidation and carbon cycling in ferruginous lakes.



1. ^Chloe Wasendorf and Audrey McCombs: “Congruence testing to validate narrow-band concept inventories in genetics” Presented at Society for the Advancement of Biology Education Research (SABER 2021); Non-presenting Co-Authors for the project: Nancy Boury, Rebecca Seipelt-Theimann, Brock Couch, Patrick Armstrong

Importance – Creation and implementation of a new statistical method to directly verify the validity of multiple choice questions in a concept inventory.  This increases the usefulness and provides more information about how this multiple choice assessment is capturing student thinking both before and after instruction. 

2. Nancy Boury and Gwendolyn Knapp: “Development and Implementation of a digital Scientific Literacy Internship” Presented at the American Society for Microbiology Conference of Undergraduate Educators (ASMCUE); Non-presenting Co-authors: Kanwal Alverez, Amaya Costas, Rebecca Seipelt-Thiemann

Importance – Described how to use TWiM or other science podcasts to host a capstone or science literacy project.   

3. Nancy Boury: "Use of Learning Games to Increase Student Engagement in General Microbiology Courses" Presented at ASMCUE 2021

Importance – Disseminating curricular innovations to other microbiology educators