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Background Blood-feeding insects are important vectors for an array of zoonotic pathogens. While previous efforts toward generating molecular resources have largely focused on major vectors of global medical and veterinary importance, molecular data across a large number of hematophagous insect taxa remain limited. Advancements in long-read sequencing technologies and associated bioinformatic pipelines provide new opportunities for targeted sequencing of insect mitochondrial (mt) genomes. For engorged hematophagous insects, such technologies can be leveraged for both insect mitogenome genome assembly and identification of vertebrate blood-meal sources. Methods We used nanopore adaptive sampling (NAS) to sequence genomic DNA from four species of field-collected, blood-engorged mosquitoes ( Aedes and Culex spp. ) and one deer fly ( Chrysops sp.). NAS was used for bioinformatical enrichment of mtDNA reads of hematophagous insects and potential vertebrate blood-meal hosts using publically available mt genomes as references. We also performed an experimental control to compare results of traditional non-NAS nanopore sequencing to the mt genome enrichment by the NAS method. Results Complete mitogenomes were assembled and annotated for all five species sequenced with NAS: Aedes trivittatus, Aedes vexans , Culex restuans , Culex territans and the deer fly, Chrysops niger . In comparison to data generated during our non-NAS control experiment, NAS yielded a substantially higher proportion of reference-mapped mtDNA reads, greatly streamlining downstream mitogenome assembly and annotation. The NAS-assembled mitogenomes ranged in length from 15,582 to 16,045 bp, contained between 78.1% and 79.0% A + T content and shared the anticipated arrangement of 13 protein-coding genes, two ribosomal RNAs, and 22 transfer RNAs. Maximum likelihood phylogenies were generated to further characterize each insect species. Additionally, vertebrate blood-meal analysis was successful in three samples sequenced, with mtDNA-based phylogenetic analyses revealing that blood-meal sources for Chrysops niger , Culex restuans and Aedes trivittatus were human, house sparrow ( Passer domesticus ) and eastern cottontail rabbit ( Sylvilagus floridanus ), respectively. Conclusions Our findings show that NAS has dual utility to simultaneously molecularly identify hematophagous insects and their blood-meal hosts. Moreover, our data indicate NAS can facilitate a wide array of mitogenomic systematic studies through novel ‘phylogenetic capture’ methods. We conclude that the NAS approach has great potential for broadly improving genomic resources used to identify blood-feeding insects, answer phylogenetic questions and elucidate complex pathways for the transmission of vector-borne pathogens. Graphical Abstract

Glycosylation of proteins is a post-translational process where oligosaccharides are attached to proteins, potentially altering their folding, epitope availability, and immune recognition. In Porcine reproductive and respiratory syndrome virus-type 2 (PRRSV-2), positive selection pressure acts on amino acid sites potentially associated with immune escape through glycan shielding. Here, we describe the patterns of potential N-glycosylation sites over time and across different phylogenetic lineages of PRRSV-2 to better understand how these may contribute to patterns of coexistence and emergence of different lineages. We screened 19,179 PRRSV GP5 sequences (2004–2021) in silico for potential N-glycosylated sites. The emergence of novel combinations of N-glycosylated sites coincided with past PRRSV epidemics in the U.S. For lineage L1A, glycosylation at residues 32, 33, 44, 51, and 57 first appeared in 2012, but represented >62% of all L1A sequences by 2015, coinciding with the emergence of the L1A 1-7-4 strain that increased in prevalence from 8 to 86% of all L1A sequences from 2012 to 2015. The L1C 1-4-4 strain that emerged in 2020 also had a distinct N-glycosylation pattern (residues 32, 33, 44, and 51). From 2020 to 2021, this pattern was responsible for 44–47% of the L1C sequences, contrasting to <5% in years prior. Our findings support the hypothesis that antigenic evolution contributes to the sequential dominance of different PRRSV strains and that N-glycosylation patterns may partially account for antigenic differences amongst strains. Further studies on glycosylation and its effect on PRRSV GP5 folding are needed to further understand how glycosylation patterns shape PRRSV occurrence.

The development and implementation of a fine-scale classification system for PRRSV-2 genetic variants represent a significant advancement for monitoring PRRSV-2 occurrence in the swine industry. Based on systematically applied criteria for variant identification using national-scale sequence data, this system addresses the shortcomings of existing classification methods by offering higher resolution and adaptability to capture emerging variants. This system provides a stable and reproducible method for classifying PRRSV-2 variants, facilitated by a freely available and regularly updated webtool for use by veterinarians and diagnostic labs. Although currently based on U.S. PRRSV-2 ORF5 sequences, this system can be expanded to include sequences from other countries, paving the way for a standardized global classification system. By enabling accurate and improved discrimination of PRRSV-2 genetic variants, this classification system significantly enhances the ability to monitor, research, and respond to PRRSV-2 outbreaks, ultimately supporting better management and control strategies in the swine industry.

Despite extensive use of vaccination, porcine reproductive and respiratory syndrome virus type 2 (PRRSV-2) continues to evolve, likely driven by escape from natural or vaccine-derived immunity. However, direct evidence of vaccine-induced evolutionary pressure remains limited. Here, we tracked the evolution of PRRSV-2 sublineage 1A strain IA/2014 (variant 1A-unclassified) genome from infection chains of sequentially infected pigs under different immune conditions. Weaned pigs were divided into three groups: a non-immunized control group and two groups vaccinated with different modified live virus (MLV) vaccines, namely Prevacent® PRRS MLV (variant 1D.2) and Ingelvac PRRS® MLV (variant 5A.1). Sixty-four days post-vaccination, the pigs were challenged with IA/2014 PRRSV-2. Virus infection chains (which used serum from pigs in batch to infect batch  + 1) were maintained across six sequential batches of roughly seven pigs each, allowing for virus evolution to occur across the ~ 84 days of the infection chain. A total of 110 serum samples were successfully sequenced. Vaccinated groups exhibited over twice the genetic divergence from the original challenge virus (0.3%-0.4% mean nucleotide distance) compared to non-immunized group (0.15%). Variability was concentrated in ORF1a and ORF1b. Deep sequencing revealed more rapid shifts of viral quasispecies composition in vaccinated pigs, and more homogeneous viral populations over batches compared to non-immunized pigs. Selection pressure analyses indicated strong purifying selection in one vaccinated group, though without clear signals at known antigenic sites in all treatment groups. However, vaccinated pigs had significantly higher cycle threshold values ( <.001), indicating lower viral loads and suggesting potential fitness limitations for highly diverged viruses in immunized pigs. These findings demonstrate that MLV vaccination can exert substantial evolutionary pressure on PRRSV-2, driving genetic diversification and highlighting the need for continuous PRRS monitoring and adaptive control strategies.

Abstract Despite extensive use of vaccination, porcine reproductive and respiratory syndrome virus type 2 (PRRSV-2) continues to evolve, likely driven by escape from natural or vaccine-derived immunity. However, direct evidence of vaccine-induced evolutionary pressure remains limited. Here, we tracked the evolution of PRRSV-2 sublineage 1A strain IA/2014 (variant 1A-unclassified) genome from infection chains of sequentially infected pigs under different immune conditions. Weaned pigs were divided into three groups: a non-immunized control group and two groups vaccinated with different modified live virus (MLV) vaccines, namely Prevacent® PRRS MLV (variant 1D.2) and Ingelvac PRRS® MLV (variant 5A.1). Sixty-four days post-vaccination, the pigs were challenged with IA/2014 PRRSV-2. Virus infection chains (which used serum from pigs in batch n to infect batch n + 1) were maintained across six sequential batches of roughly seven pigs each, allowing for virus evolution to occur across the ~ 84 days of the infection chain. A total of 110 serum samples were successfully sequenced. Vaccinated groups exhibited over twice the genetic divergence from the original challenge virus (0.3%–0.4% mean nucleotide distance) compared to non-immunized group (0.15%). Variability was concentrated in ORF1a and ORF1b. Deep sequencing revealed more rapid shifts of viral quasispecies composition in vaccinated pigs, and more homogeneous viral populations over batches compared to non-immunized pigs. Selection pressure analyses indicated strong purifying selection in one vaccinated group, though without clear signals at known antigenic sites in all treatment groups. However, vaccinated pigs had significantly higher cycle threshold values (P<.001), indicating lower viral loads and suggesting potential fitness limitations for highly diverged viruses in immunized pigs. These findings demonstrate that MLV vaccination can exert substantial evolutionary pressure on PRRSV-2, driving genetic diversification and highlighting the need for continuous PRRS monitoring and adaptive control strategies.

The Summer Chemistry Workshop at Armstrong Atlantic State University is a graduate course designed to meet a broad spectrum of needs of in-service secondary science teachers. The workshop addresses multiple challenges faced by in-service science teachers and provides them with the tools required for effective laboratory instruction. It incorporates a number of topics related to laboratory instruction, including keeping chemistry content current and highlighting its universal relevance, learning (usually for the first time) how to safely store and dispose of hazardous chemicals, and establishing a synergistic relationship between secondary and university science faculty. An overview of the workshop and its advantages are presented.

Existing genetic classification systems for porcine reproductive and respiratory syndrome virus 2 (PRRSV-2), such as restriction fragment length polymorphisms (RFLPs) and sub-lineages, are unreliable indicators of genetic relatedness or lack sufficient resolution for epidemiological monitoring routinely conducted by veterinarians. Here, we outline a fine-scale classification system for PRRSV-2 genetic variants in the U.S. Based on >25,000 U.S. open-reading-frame 5 (ORF5) sequences, sub-lineages were divided into genetic variants using a clustering algorithm. Through classifying new sequences every three months and systematically identifying new variants across eight years, we demonstrated that prospective implementation of the variant classification system produced robust, reproducible results across time and can dynamically accommodate new genetic diversity arising from virus evolution. From 2015 and 2023, 118 variants were identified, with ∼48 active variants per year, of which 26 were common (detected >50 times). Mean within-variant genetic distance was 2.4% (max: 4.8%). The mean distance to the closest related variant was 4.9%. A routinely updated webtool (https://stemma.shinyapps.io/PRRSLoom-variants/) was developed and is publicly available for end-users to assign newly generated sequences to a variant ID. This classification system relies on U.S. sequences from 2015 onwards; further efforts are required to extend this system to older or international sequences. Finally, we demonstrate how variant classification can better discriminate between previous and new strains on a farm, determine possible sources of new introductions into a farm/system, and track emerging variants regionally. Adoption of this classification system will enhance PRRSV-2 epidemiological monitoring, research, and communication, and improve industry responses to emerging genetic variants. The development and implementation of a fine-scale classification system for PRRSV-2 genetic variants represents a significant advancement for monitoring PRRSV-2 occurrence in the swine industry. Based on systematically-applied criteria for variant identification using national-scale sequence data, this system addresses the shortcomings of existing classification methods by offering higher resolution and adaptability to capture emerging variants. This system provides a stable and reproducible method for classifying PRRSV-2 variants, facilitated by a freely available and regularly updated webtool for use by veterinarians and diagnostic labs. Although currently based on U.S. PRRSV-2 ORF5 sequences, this system can be expanded to include sequences from other countries, paving the way for a standardized global classification system. By enabling accurate and improved discrimination of PRRSV-2 genetic variants, this classification system significantly enhances the ability to monitor, research, and respond to PRRSV-2 outbreaks, ultimately supporting better management and control strategies in the swine industry.

The Summer Chemistry Workshop at Armstrong Atlantic State University was designed to meet the needs of secondary school science teachers and focuses on the comprehensive laboratory component of science instruction. This workshop is discussed.

A core question in evolutionary biology is whether convergent phenotypic evolution is driven by convergent molecular changes in proteins or regulatory regions.We combined phylogenomic, developmental, and epigenomic analysis of 11 new genomes of paleognathous birds, including an extinct moa, to show that convergent evolution of regulatory regions, more so than protein-coding genes, is prevalent among developmental pathways associated with independent losses of flight. A Bayesian analysis of 284,001 conserved noncoding elements, 60,665 of which are corroborated as enhancers by open chromatin states during development, identified 2355 independent accelerations along lineages of flightless paleognaths, with functional consequences for driving gene expression in the developing forelimb. Our results suggest that the genomic landscape associated with morphological convergence in ratites has a substantial shared regulatory component.

The gut microbiota is a complex consortium of microorganisms with the ability to influence important aspects of host health and development. Harnessing this \"microbial organ\" for biomedical applications requires clarifying the degree to which host and bacterial factors act alone or in combination to govern the stability of specific lineages. To address this issue, we combined bacteriological manipulation and light sheet fluorescence microscopy to monitor the dynamics of a defined two-species microbiota within a vertebrate gut. We observed that the interplay between each population and the gut environment produces distinct spatiotemporal patterns. As a consequence, one species dominates while the other experiences sudden drops in abundance that are well fit by a stochastic mathematical model. Modeling revealed that direct bacterial competition could only partially explain the observed phenomena, suggesting that a host factor is also important in shaping the community. We hypothesized the host determinant to be gut motility, and tested this mechanism by measuring colonization in hosts with enteric nervous system dysfunction due to a mutation in the ret locus, which in humans is associated with the intestinal motility disorder known as Hirschsprung disease. In mutant hosts we found reduced gut motility and, confirming our hypothesis, robust coexistence of both bacterial species. This study provides evidence that host-mediated spatial structuring and stochastic perturbation of communities can drive bacterial population dynamics within the gut, and it reveals a new facet of the intestinal host-microbe interface by demonstrating the capacity of the enteric nervous system to influence the microbiota. Ultimately, these findings suggest that therapeutic strategies targeting the intestinal ecosystem should consider the dynamic physical nature of the gut environment.