Combined genomic and structural analyses of a cultured magnetotactic bacterium reveals its niche adaptation to a dynamic environment.

BACKGROUND: Magnetotactic bacteria (MTB) are a unique group of prokaryotes that have a potentially high impact on global geochemical cycling of significant primary elements because of their metabolic plasticity and the ability to biomineralize iron-rich magnetic particles called magnetosomes. Understanding the genetic composition of the few cultivated MTB along with the unique morphological features of this group of bacteria may provide an important framework for discerning their potential biogeochemical roles in natural environments. RESULTS: Genomic and ultrastructural analyses were combined to characterize the cultivated magnetotactic coccus Magnetofaba australis strain IT-1. Cells of this species synthesize a single chain of elongated, cuboctahedral magnetite (Fe3O4) magnetosomes that cause them to align along magnetic field lines while they swim being propelled by two bundles of flagella at velocities up to 300 µm s-1. High-speed microscopy imaging showed the cells move in a straight line rather than in the helical trajectory described for other magnetotactic cocci. Specific genes within the genome of Mf. australis strain IT-1 suggest the strain is capable of nitrogen fixation, sulfur reduction and oxidation, synthesis of intracellular polyphosphate granules and transporting iron with low and high affinity. Mf. australis strain IT-1 and Magnetococcus marinus strain MC-1 are closely related phylogenetically although similarity values between their homologous proteins are not very high. CONCLUSION: Mf. australis strain IT-1 inhabits a constantly changing environment and its complete genome sequence reveals a great metabolic plasticity to deal with these changes. Aside from its chemoautotrophic and chemoheterotrophic metabolism, genomic data indicate the cells are capable of nitrogen fixation, possess high and low affinity iron transporters, and might be capable of reducing and oxidizing a number of sulfur compounds. The relatively large number of genes encoding transporters as well as chemotaxis receptors in the genome of Mf. australis strain IT-1 combined with its rapid swimming velocities, indicate that cells respond rapidly to environmental changes.

Going Online in Pandemic Time: A DivulgaMicro Workshop Experience.

DivulgaMicro is a Brazilian science communication and outreach project run by three young female scientists. In 2020, due to the COVID-19 pandemic, we promoted the first virtual edition of the DivulgaMicro Workshop. Here, we describe adaptations implemented to deliver the virtual edition and its assessment by the participants. We offered a 3-day workshop addressing manuscript writing and publishing, poster design and oral presentations, and strategies for effectively communicating with the lay public on Days 1, 2, and 3, respectively. Each daily session was divided into short lectures and active learning through interactive and cooperative activities. We applied pre- and postsession surveys daily to assess participants' learning, with an opinion questionnaire at the end of the workshop. We selected 50 of 221 applicants, but only 38 of those selected participated in the workshop. Correct answers were significantly higher (p < 0.01) in the postsession surveys each day. Most of the 34 participants who answered the opinion questionnaire (97%) would recommend the workshop to their colleagues. Participants stated that the workshop content was transmitted in a clear and straightforward manner, and they considered the online format suitable for knowledge acquisition. Participants were satisfied with the organization, dynamics, and interactivity. Topics addressed on Day 3 (61.8%) and Day 1 (23.5%) were most liked and were considered most useful in the participants' careers. We believe that the overall success of the workshop is due to the combination of short lectures with active-learning activities, the use of virtual platforms that enabled effective communication between participants and instructors, and the support of our collaborators.