Harnessing Population Genetics for Pest Management: Theory and Application for Urban Rats

Effective management of rodent pests requires an ecological understanding of how they move through their environment and how those movements influence the invasion, persistence, or reinvasion of problematic colonies. Traditional methodologies used to describe rodent movement patterns, such as mark-recapture, are hindered by their time-consuming nature and limited geographic scope. As such, our understanding of how rodents interact with urban environments remains limited. Population genetic principles and tools have the capacity to greatly increase our understanding of rodent population dynamics, ecological relationships, and movements across space, but this field is often unapproachable to non-scientist pest management professionals (PMPs). In this commentary, we aim to promote collaborative and integrative rodent pest management by introducing relevant population genetic principles, providing examples of their applications in studies of urban brown rats (Rattus norvegicus), and proposing future initiatives that link scientific, private, and government entities. We reinterpret results from a 2018 study of brown rats in Vancouver, British Columbia, Canada to show how genetic relationships among individual brown rats can be used to understand the geographic distribution of genetic clusters (i.e., colonies), natural barriers to migration, and the spatial scale of dispersal. While the 2018 study originally aimed to describe patterns of population genetic structure to understand the influence of urban landscapes on rats, here we describe how these results can be exploited by PMPs to directly inform the creation of management units and decrease the likelihood of rapid post-treatment reinvasion. Further, we discuss the difficulties inherent in population genetic studies and the potential for high-quality model sites to develop generalizable strategies. Overall, we hope to expand the toolbox of PMPs, foster collaboration, and move toward more informed and sustainable management strategies

Pseudophosphorylation of tau at S422 enhances SDS-stable dimer formation and impairs both anterograde and retrograde fast axonal transport

AbstractIn Alzheimer's disease (AD), tau undergoes numerous modifications, including increased phosphorylation at serine-422 (pS422). In the human brain, pS422 tau protein is found in prodromal AD, correlates well with cognitive decline and neuropil thread pathology, and appears associated with increased oligomer formation and exposure of the N-terminal phosphatase-activating domain (PAD). However, whether S422 phosphorylation contributes to toxic mechanisms associated with disease-related forms of tau remains unknown. Here, we report that S422-pseudophosphorylated tau (S422E) lengthens the nucleation phase of aggregation without altering the extent of aggregation or the types of aggregates formed. When compared to unmodified tau aggregates, the S422E modification significantly increased the amount of SDS-stable tau dimers, despite similar levels of immunoreactivity with an oligomer-selective antibody (TOC1) and another antibody that reports PAD exposure (TNT1). Vesicle motility assays in isolated squid axoplasm further revealed that S422E tau monomers inhibited anterograde, kinesin-1 dependent fast axonal transport (FAT). Unexpectedly, and unlike unmodified tau aggregates, which selectively inhibit anterograde FAT, aggregates composed of S422E tau were found to inhibit both anterograde and retrograde FAT. Highlighting the relevance of these findings to human disease, pS422 tau was found to colocalize with tau oligomers and with a fraction of tau showing increased PAD exposure in the human AD brain. This study identifies novel effects of pS422 on tau biochemical properties, including prolonged nucleation and enhanced dimer formation, which correlate with a distinct inhibitory effect on FAT. Taken together, these findings identify a novel mechanistic basis by which pS422 confers upon tau a toxic effect that may directly contribute to axonal dysfunction in AD and other tauopathies

Wnt/β-catenin signaling is required for development of the exocrine pancreas

BACKGROUND: β-catenin is an essential mediator of canonical Wnt signaling and a central component of the cadherin-catenin epithelial adhesion complex. Dysregulation of β-catenin expression has been described in pancreatic neoplasia. Newly published studies have suggested that β-catenin is critical for normal pancreatic development although these reports reached somewhat different conclusions. In addition, the molecular mechanisms by which loss of β-catenin affects pancreas development are not well understood. The goals of this study then were; 1] to further investigate the role of β-catenin in pancreatic development using a conditional knockout approach and 2] to identify possible mechanisms by which loss of β-catenin disrupts pancreatic development. A Pdx1-cre mouse line was used to delete a floxed β-catenin allele specifically in the developing pancreas, and embryonic pancreata were studied by immunohistochemistry and microarray analysis. RESULTS: Pdx1-cre floxed β-catenin animals were viable but demonstrated small body size and shortened median survival. The pancreata from knockout mice were hypoplastic and histologically demonstrated a striking paucity of exocrine pancreas, acinar to duct metaplasia, but generally intact pancreatic islets containing all lineages of endocrine cells. In animals with extensive acinar hypoplasia, putative hepatocyte transdifferention was occasionally observed. Obvious and uniform pancreatic hypoplasia was observed by embryonic day E16.5. Transcriptional profiling of Pdx1-cre floxed β-catenin embryonic pancreata at E14.5, before there was a morphological phenotype, revealed significant decreases in the β-catenin target gene N-myc, and the basic HLH transcription factor PTF1, and an increase of several pancreatic zymogens compared to control animals. By E16.5, there was a dramatic loss of exocrine markers and an increase in Hoxb4, which is normally expressed anterior to the pancreas. CONCLUSION: We conclude that β-catenin expression is required for development of the exocrine pancreas, but is not required for development of the endocrine compartment. In contrast, β-catenin/Wnt signaling appears to be critical for proliferation of PTF1+ nascent acinar cells and may also function, in part, to maintain an undifferentiated state in exocrine/acinar cell precursors. Finally, β-catenin may be required to maintain positional identity of the pancreatic endoderm along the anterior-posterior axis. This data is consistent with the findings of frequent β-catenin mutations in carcinomas of acinar cell lineage seen in humans

Radical Interrelated Qualitative Space in the Midst of Multipandemics: A Collaborative Scholarly Personal Narrative

Given the current unprecedented multiple pandemics of COVID-19, anti-Black and anti-Asian violence, and white supremacy, we—a group of graduate students and a faculty member who hold diverse identities across disciplines, race, gender, nationality, and additional categories—came together to focus on qualitative research as an ontological, epistemological, and axiological space toward community and culture change. Specifically, we took up scholarly personal narrative, which centers postmodernism and focuses on the reality that “we see what we believe; we observe what we narrate; we transform what we reframe. ”What emerged were radical interrelated understandings of privilege, guilt, and the importance of kinship. As such, this vulnerable group reflected on graduate student experiences with multiple pandemics and how the academy may enact transformative change, reframing our own understandings of qualitative space

Global population divergence and admixture of the brown rat (Rattus norvegicus)

Native to China and Mongolia, the brown rat (Rattus norvegicus) now enjoys a worldwide distribution. While black rats and the house mouse tracked the regional development of human agricultural settlements, brown rats did not appear in Europe until the 1500s, suggesting their range expansion was a response to relatively recent increases in global trade. We inferred the global phylogeography of brown rats using 32 k SNPs, and detected 13 evolutionary clusters within five expansion routes. One cluster arose following a southward expansion into Southeast Asia. Three additional clusters arose from two independent eastward expansions: one expansion from Russia to the Aleutian Archipelago, and a second to western North America. Westward expansion resulted in the colonization of Europe from which subsequent rapid colonization of Africa, the Americas and Australasia occurred, and multiple evolutionary clusters were detected. An astonishing degree of fine-grained clustering between and within sampling sites underscored the extent to which urban heterogeneity shaped genetic structure of commensal rodents. Surprisingly, few individuals were recent migrants, suggesting that recruitment into established populations is limited. Understanding the global population structure of R. norvegicus offers novel perspectives on the forces driving the spread of zoonotic disease, and aids in development of rat eradication programmes

Investigating the Impact of an Innovative Intergenerational Physical Activity Program

There is limited evidence in the current body of literature regarding the implementation of an intergenerational programs that include physical activity as a key component. PURPOSE: The goal of this study was to evaluate an intergenerational program, Grow and Play, with an emphasis in physical activity for older adults and children during an afterschool program at the local community center. METHODS: Eight community-dwelling older adults (mean age: 80.7) and nine children (mean age: 9.77) joined Grow and Play at the Winter Park Community Center for nine weeks for a total of 16 sessions. The Grow and Play protocol consisted of baseline measurements, including fall-risk assessments, a twice-weekly 90-minute intervention over nine weeks, and post-assessments after the intervention was completed. Measures were analyzed via paired t-tests through SPSS using an alpha level of 0.1. RESULTS: The data highlights high feasibility and acceptability for Grow and Play, as well as treatment adherence, fidelity to the program, and session evaluations are outlined. CONCLUSION: This article guides future creation of intergenerational programs by highlighting the importance of physical activity as a main component, but also the ability to improve adherence and benefits of these programs

Harnessing Population Genetics for Pest Management: Theory and Application for Urban Rats (Abstract)

Effective management of rodent pests requires an ecological understanding of how they move through their environment, and how those movements influence the invasion, persistence, or reinvasion of problematic colonies. Traditional methodologies used to describe rodent movement patterns, such as mark-recapture, are hindered by their time-consuming nature and limited geographic scope. As such, our understanding of how rodents interact with urban environments remains limited. Population genetic principles and tools have the capacity to greatly increase our understanding of rodent population dynamics, ecological relationships, and movements across space but this field is often unapproachable to non-scientist pest management professionals. In this paper we aim to promote collaborative and integrative rodent pest management by introducing relevant population genetic principles, providing examples of their applications in studies of urban brown rats, and proposing future initiatives that link scientific, private, and government entities. Using a densely-sampled brown rat population in the city of Vancouver, BC we show how genetic relationships among individual brown rats can be leveraged to understand the geographic distribution of genetic clusters (i.e., colonies), natural barriers to migration, and the spatial scale of dispersal. We describe how these results can be exploited by PMPs to directly inform the creation of management units and decrease the likelihood of rapid post-treatment reinvasion. Further, we discuss the difficulties inherent in population genetic studies and the potential for high-quality model sites to develop generalizable strategies. Overall, we hope to expand the toolbox of pest management professionals, foster collaboration, and move towards more informed and sustainable management strategies

Data from: Urban rat races: spatial population genomics of brown rats (Rattus norvegicus) compared across multiple cities

Urbanization often substantially influences animal movement and gene flow. However, few studies to date have examined gene flow of the same species across multiple cities. In this study, we examine brown rats (Rattus norvegicus) to test hypotheses about the repeatability of neutral evolution across four cities: Salvador, Brazil; New Orleans, USA; Vancouver, Canada; New York City, USA. At least 150 rats were sampled from each city and genotyped for a minimum of 15,000 genome-wide SNPs. Levels of genome-wide diversity were similar across cities, but varied across neighborhoods within cities. All four populations exhibited high spatial autocorrelation at the shortest distance classes (< 500 m) due to limited dispersal. Coancestry and evolutionary clustering analyses identified genetic discontinuities within each city that coincided with a resource desert in New York City, major waterways in New Orleans, and roads in Salvador and Vancouver. Such replicated studies are crucial to assessing the generality of predictions from urban evolution, and have practical applications for pest management and public health. Future studies should include a range of global cities in different biomes, incorporate multiple species, and examine the impact of specific characteristics of the built environment and human socioeconomics on gene flow

PLINK .map file for Salvador, Brazil rat SNP Genotypes

PLINK .map file for Salvador, Brazil SNP genotypes. The genotypes themselves are in the .ped file of the same name, and the .map file contains the chromosomal coordinates for each SNP