Biology subjects

Orr, T. J.

Publications and source records attributed to Orr, T. J..

3 recordsLinked to original sources

bioRxiv2023

Science abhors a surveillance vacuum: detection of ticks and tick-borne bacteria in southern New Mexico through passive surveillance

Robust tick surveillance enhances diagnosis and prevention of tick-borne pathogens, yet surveillance efforts in the U.S. are highly uneven, resulting in large surveillance vacuums, one of which spans the state of New Mexico. As part of a larger effort to fill this vacuum, we conducted both active and passive tick sampling in New Mexico, focusing on the southern portion of the state. We conducted active tick sampling using dragging and CO2 trapping at 45 sites across Hidalgo, Dona Ana, Otero, and Eddy counties periodically between June 2021 and August 2022. We also conducted opportunistic, passive tick sampling in 2021 and 2022 from animals harvested by hunters or captured or collected by researchers and animals housed in animal hospitals, shelters, and farms. All pools of ticks were screened for Rickettsia rickettsii, R. parkeri, R. amblyommatis, Ehrlichia ewingii, and E. chaffeensis. Active sampling yielded no ticks. Passive sampling yielded 497 ticks comprising Carios kelleyi from pallid bats, Rhipicephalus sanguineus from dogs, mule deer, and Rocky Mountain elk, Otobius megnini from dogs, cats, horses, and Coues deer, Dermacentor parumapertus from dogs and black-tailed jackrabbits, D. albipictus from domesticated cats, mule deer and Rocky Mountain elk, and Dermacentor spp. from American black bear, Rocky Mountain elk, and mule deer. One pool of D. parumapterus from a black-tailed jackrabbit in Luna County tested positive for R. parkeri, an agent of spotted fever rickettsiosis. Additionally, a spotted fever group Rickettsia was detected in 6 of 7 Carios kelleyi pools. Two ticks showed morphological abnormalities; however, these samples did not test positive for any of the target pathogens, and the cause of the abnormalities is unknown. Passive surveillance yielded five identified species of ticks from three domestic and six wild mammal species. One tick pool from a black-tailed jackrabbit was found to harbor Rickettsia parkeri, and six pools of Carios kelleyi ticks, argasid ticks that have been reported to bite humans, were found to harbor a spotted fever group Rickettsia. Our findings update tick distributions and inform the public, medical, and veterinary communities of the potential tick-borne pathogens present in southern New Mexico.

zoology↗

bioRxiv2021

Trio-binned genomes of the woodrats Neotoma bryanti and N. lepida reveal novel gene islands and rapid copy number evolution of xenobiotic metabolizing cytochrome p450 genes

The genomic architecture underlying the origins and maintenance of biodiversity is an increasingly accessible feature of species, due in large part to third-generation sequencing and novel analytical toolsets. Woodrats of the genus Neotoma provide a unique opportunity to study how vertebrate herbivores respond to climate change, as two sister species (N. bryanti and N. lepida) independently achieved a major dietary feat - switching to the novel and toxic food source creosote bush (Larrea tridentata) - in the aftermath of a natural warming event. To better understand the genetic mechanisms underlying this ability, we employed a trio binning sequencing approach with a N. bryanti x N. lepida F1 hybrid, resulting in phased, chromosome-level, highly complete, haploid genome assemblies for each species from one individual. Using these new assemblies, we explored the genomic architecture of three cytochrome p450 subfamilies (2A, 2B, and 3A) that play key roles in the metabolism of naturally occurring toxic dietary compounds. We found that woodrats show expansions of all three p450 gene families, including the evolution of multiple novel gene islands within the 2B and 3A subfamilies. Our assemblies demonstrate that trio binning from an F1 hybrid rodent effectively recovers parental genomes from species that diverged more than a million years ago. Turnover and novelty in detoxification gene islands in herbivores is widespread within distinct p450 subfamilies, and may have provided the crucial substrate for dietary adaptation during environmental change.

genomics↗

bioRxiv2018

Metagenomic sequencing provides insights into the location of microbial detoxification in the gut of a small mammalian herbivore

Microbial detoxification of plant defense compounds influences the use of certain plants as food sources by herbivores. The location of microbial detoxification along the gut could have profound influences on the distribution, metabolism, and tolerance to toxic compounds. Stephens woodrats (Neotoma stephensi) specialize on juniper, which is heavily defended by numerous defensive compounds, such as oxalate, phenolics, and monoterpenes. Woodrats maintain two gut chambers harboring dense microbial communities: a foregut chamber proximal to the major site of toxin absorption, and a cecal chamber in their hindgut. We performed several experiments to investigate the location of microbial detoxification in the woodrat gut. First, we measured levels of toxins across gut chambers. Compared to food material, oxalate concentrations were immediately lower in the foregut chamber, while concentrations of terpenes remain high in the foregut, and are lowest in the cecal chamber. We also conducted metagenomic sequencing of the foregut and cecal chambers to compare microbial functions. We found that the majority of genes associated with detoxification functions were more abundant in the cecal chamber. However, some genes associated with degradation of oxalate and phenolic compounds were more abundant in the foregut. Thus, it seems that microbial detoxification may take place in various chambers depending on the class of chemical compound. We hypothesize that the location of microbial detoxification could impact the tolerance of animals to these compounds, which may have ecological and evolutionary consequences.

microbiology↗