Teaching in the Time of COVID-19: Creation of a Digital Internship to Develop Scientific Thinking Skills and Create Science Literacy Exercises for Use in Remote Classrooms.

The extreme academic and social disruption caused by COVID-19 in the spring and summer of 2020 led to the loss of many student internships. We report here our creation of a novel internship for students majoring in the biological sciences. Student interns worked together to systematically categorize multiple episodes of This Week in Microbiology (TWiM). They annotated episodes by labeling relevant ASM fundamental curricular guidelines and the microbiology techniques described in several podcast episodes. Interns worked together, which advanced their written and oral communication skills while improving their scientific thinking skills. Faculty then enhanced each annotation by adding short figure-reading exercises that can be used in a variety of educational settings to teach science literacy. When surveyed, students reported greater confidence in analyzing and interpreting results from a variety of microbiological methods, improved communication of fundamental microbiology concepts in written and oral form, and enhanced ability to collaborate with others. Combined, this digital internship provided a unique opportunity for students to develop critical technical and scientific thinking skills and generated useful open education resources for teaching general microbiology in the form of annotated podcasts.

Using Virtual Simulations in Online Laboratory Instruction and Active Learning Exercises as a Response to Instructional Challenges during COVID-19.

The onset of the COVID-19 pandemic in the spring of 2020 thrust instructors into a world of frenzy, presenting unique challenges to delivering course content. A particular challenge was determining suitable substitutes for wet lab experiments that are often comprised in science labs. Recognizing that this problem was not short-term, I started to look into virtual substitutions to be implemented in the 2020-2021 academic year. Virtual simulations can replace labs, be incorporated as pre-lab assignments, or used as active-learning or experiential learning exercises in a traditional classroom setting while providing low-cost, safe, and acceptable solutions to the current problem. Virtual simulations were examined on different platforms, including Labster, McGraw Hill Connect Virtual Labs, HHMI BioInteractive, Learn.Genetics, Virtual Interactive Bacteriology Laboratory, and Biology Corner. The goal was to provide faculty around the world with a reference list of virtual simulations that are aligned to specific AAAS and ASM student learning outcomes. These simulations are discussed in terms of content, features, and advantages of use. A list of lab exercises aligned to biology courses (microbiology, genetics, and cell biology) is also provided.

Pathogenomics of Culex quinquefasciatus and meta-analysis of infection responses to diverse pathogens.

The mosquito Culex quinquefasciatus poses a substantial threat to human and veterinary health as a primary vector of West Nile virus (WNV), the filarial worm Wuchereria bancrofti, and an avian malaria parasite. Comparative phylogenomics revealed an expanded canonical C. quinquefasciatus immune gene repertoire compared with those of Aedes aegypti and Anopheles gambiae. Transcriptomic analysis of C. quinquefasciatus genes responsive to WNV, W. bancrofti, and non-native bacteria facilitated an unprecedented meta-analysis of 25 vector-pathogen interactions involving arboviruses, filarial worms, bacteria, and malaria parasites, revealing common and distinct responses to these pathogen types in three mosquito genera. Our findings provide support for the hypothesis that mosquito-borne pathogens have evolved to evade innate immune responses in three vector mosquito species of major medical importance.

Distinct melanization pathways in the mosquito Aedes aegypti.

Serine protease cascades are involved in blood coagulation and immunity. In arthropods, they regulate melanization, which plays an important role in immune defense and wound healing. However, the mechanisms underlying melanization pathways are not completely characterized. We found that in the mosquito Aedes aegypti, there are two distinct melanization activation pathways carried out by different modules of serine proteases and their specific inhibitors serpins. Immune melanization proteases (IMP-1 and IMP-2) and Serpin-1 mediate hemolymph prophenoloxidase cleavage and immune response against the malaria parasite. Tissue melanization, exemplified by the formation of melanotic tumors, is controlled by tissue melanization protease (CLIPB8), IMP-1, and Serpin-2. In addition, serine proteases CLIPB5 and CLIPB29 are involved in activation of Toll pathway by fungal infection or by infection-independent manner, respectively. Serpin-2 is implicated in the latter activation of Toll pathway. This study revealed the complexity underlying melanization and Toll pathway in mosquitoes.

The role of NF-kappaB factor REL2 in the Aedes aegypti immune response.

Mosquitoes transmit numerous diseases that continue to be an enormous burden on public health worldwide. Transgenic mosquitoes impervious to vector-borne pathogens, in concert with vector control and drug and vaccine development, comprise an arsenal of means anticipated to defeat mosquito-spread diseases in the future. Mosquito transgenesis allows tissue-specific manipulation of their major immune pathways and enhances the ability to study mosquito-pathogen interactions. Here, we report the generation of two independent transgenic strains of Aedes aegypti overexpressing the NF-?B transcriptional factor REL2, a homologue of Drosophila Relish, which is shown to be under the control of the vitellogenin promoter in the mosquito fat body after a blood meal. We show that this REL2 overexpression in the fat body results in transcriptional activation of Defensins A, C, and D, and Cecropins A and N, as well as translation and secretion of Defensin A protein into the hemolymph. We also demonstrate that induction of REL2 results in the increased resistance of the mosquito to tested Gram-negative and Gram-positive bacteria. Importantly, induction of transgenic REL2 leads to the significant decrease in susceptibility of A. aegypti to Plasmodium gallinaceum infection. Consistently, RNAi knockdown of REL2 in wild-type mosquitoes results in a delay in Defensin A and Cecropin A expression in response to infection and in increased susceptibility to both bacteria and P. gallinaceum. Moreover, our transgenic assays demonstrate that the N-terminus of the mosquito REL2, which includes the His/Gln-rich and serine-rich regions, plays a role in its transactivation properties.

Mosquito RUNX4 in the immune regulation of PPO gene expression and its effect on avian malaria parasite infection.

Prophenoloxidases (PPOs) are key enzymes of the melanization reaction, which is a prominent defense mechanism of arthropods. The mosquito Aedes aegypti has ten PPO genes in the genome, four of which (PPO1, PPO3, PPO5, and PPO8) were expressed in response to microbial infection. Cactus depletion resulted in transcriptional activation of these four genes, suggesting this up-regulation to be under the control of the Toll pathway. The silencing of Cactus also led to developmental arrest and death of the avian malaria parasite, Plasmodium gallinaceum. We discovered that RUNT-related transcription factor 4 (RUNX4), the orthologue of Drosophila Lozenge, bound to the RUNT binding motif in the promoter of mosquito PPO genes and stimulated the expression of Drosophila PPO-A1 and PPO3 in S2 cell line. The immune effects caused by Cactus depletion were eliminated by double knockdown of Cactus/RUNX4. These findings suggest that RUNX4 regulates PPO gene expression under the control of the Toll pathway and plays a critical role in restricting parasite development.

Evolutionary dynamics of immune-related genes and pathways in disease-vector mosquitoes.

Mosquitoes are vectors of parasitic and viral diseases of immense importance for public health. The acquisition of the genome sequence of the yellow fever and Dengue vector, Aedes aegypti (Aa), has enabled a comparative phylogenomic analysis of the insect immune repertoire: in Aa, the malaria vector Anopheles gambiae (Ag), and the fruit fly Drosophila melanogaster (Dm). Analysis of immune signaling pathways and response modules reveals both conservative and rapidly evolving features associated with different functional gene categories and particular aspects of immune reactions. These dynamics reflect in part continuous readjustment between accommodation and rejection of pathogens and suggest how innate immunity may have evolved.