Jacob H Theil

Dr. Jacob H Theil

University of California, Davis, Davis, California, USA
+1
orcid

Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 February 2009 in Ecology
Verified
Journal Article
Open access
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SSSharon Strauss
Sharon Strauss
MSMaureen L. Stanton
Maureen L. Stanton
NENancy C. Emery
Nancy C. Emery
CBCarrie A. Bradley
Carrie A. Bradley
ACAlexandra Carleton
Alexandra Carleton
EYEric M. Yoshizuka
Eric M. Yoshizuka
Although much of the theory on the success of invasive species has been geared at escape from specialist enemies, the impact of introduced generalist invertebrate herbivores on both native and introduced plant species has been underappreciated. The role of nocturnal invertebrate herbivores in structuring plant communities has been examined extensively in Europe, but less so in North America. Many nocturnal generalists (slugs, snails, and earwigs) have been introduced to North America, and 96% of herbivores found during a night census at our California Central Valley site were introduced generalists. We explored the role of these herbivores in the distribution, survivorship, and growth of 12 native and introduced plant species from six families. We predicted that introduced species sharing an evolutionary history with these generalists might be less vulnerable than native plant species. We quantified plant and herbivore abundances within our heterogeneous site and also established herbivore removal experiments in 160 plots spanning the gamut of microhabitats. As 18 collaborators, we checked 2000 seedling sites every day for three weeks to assess nocturnal seedling predation. Laboratory feeding trials allowed us to quantify the palatability of plant species to the two dominant nocturnal herbivores at the site (slugs and earwigs) and allowed us to account for herbivore microhabitat preferences when analyzing attack rates on seedlings. The relationship between local slug abundance and percent cover of five common plant taxa at the field site was significantly negatively associated with the mean palatability of these taxa to slugs in laboratory trials. Moreover, seedling mortality of 12 species in open‐field plots was positively correlated with mean palatability of these taxa to both slugs and earwigs in laboratory trials. Counter to expectations, seedlings of native species were neither more vulnerable nor more palatable to nocturnal generalists than those of introduced species. Growth comparison of plants within and outside herbivore exclosures also revealed no differences between native and introduced plant species, despite large impacts of herbivores on growth. Cryptic nocturnal predation on seedlings was common and had large effects on plant establishment at our site. Without intensive monitoring, such predation could easily be misconstrued as poor seedling emergence.

6 October 2020 in Scientific Reports
Verified
Journal Article
Open access
PDF file
JTJacob H Theil
Jacob H Theil
JDJamie Ahloy Dallaire
Jamie Ahloy Dallaire
EWElin M. Weber
Elin M. Weber
BGBrianna N. Gaskill
Brianna N. Gaskill
KPKathleen R. Pritchett-Corning
Kathleen R. Pritchett-Corning
JGJoseph P. Garner
Joseph P. Garner
Injurious home-cage aggression (fighting) in mice affects both animal welfare and scientific validity. It is arguably the most common potentially preventable morbidity in mouse facilities. Existing literature on mouse aggression almost exclusively examines territorial aggression induced by introducing a stimulus mouse into the home-cage of a singly housed mouse (i.e. the resident/intruder test). However, fighting occurring in mice living together in long-term groups under standard laboratory housing conditions has barely been studied. We performed a point-prevalence epidemiological survey of fighting at a research institution with an approximate 60,000 cage census. A subset of cages was sampled over the course of a year and factors potentially influencing home-cage fighting were recorded. Fighting was almost exclusively seen in group-housed male mice. Approximately 14% of group-housed male cages were observed with fighting animals in brief behavioral observations, but only 14% of those cages with fighting had skin injuries observable from cage-side. Thus simple cage-side checks may be missing the majority of fighting mice. Housing system (the combination of cage ventilation and bedding type), genetic background, time of year, cage location on the rack, and rack orientation in the room were significant risk factors predicting fighting. Of these predictors, only bedding type is easily manipulated to mitigate fighting. Cage ventilation and rack orientation often cannot be changed in modern vivaria, as they are baked in by cookie-cutter architectural approaches to facility design. This study emphasizes the need to invest in assessing the welfare costs of new housing and husbandry systems before implementing them.

1 November 2022 in Viruses
Verified
Journal Article
Open access
PDF file
SCSarah Cook
Sarah Cook
LWLuke A. Wittenburg
Luke A. Wittenburg
VYVictoria Yan
Victoria Yan
JTJacob H Theil
Jacob H Theil
LCLuis Diego Castillo
Luis Diego Castillo
BMBrian Murphy
Brian Murphy
Feline infectious peritonitis (FIP) is a fatal disease of cats that currently lacks licensed and affordable vaccines or antiviral therapeutics. The disease has a spectrum of clinical presentations including an effusive (“wet”) form and non-effusive (“dry”) form, both of which may be complicated by neurologic or ocular involvement. The feline coronavirus (FCoV) biotype, termed feline infectious peritonitis virus (FIPV), is the etiologic agent of FIP. The objective of this study was to determine and compare the in vitro antiviral efficacies of the viral protease inhibitors GC376 and nirmatrelvir and the nucleoside analogs remdesivir (RDV), GS-441524, molnupiravir (MPV; EIDD-2801), and β-D-N4-hydroxycytidine (NHC; EIDD-1931). These antiviral agents were functionally evaluated using an optimized in vitro bioassay system. Antivirals were assessed as monotherapies against FIPV serotypes I and II and as combined anticoronaviral therapies (CACT) against FIPV serotype II, which provided evidence for synergy for selected combinations. We also determined the pharmacokinetic properties of MPV, GS-441524, and RDV after oral administration to cats in vivo as well as after intravenous administration of RDV. We established that orally administered MPV at 10 mg/kg, GS-441524 and RDV at 25 mg/kg, and intravenously administered RDV at 7 mg/kg achieves plasma levels greater than the established corresponding EC50 values, which are sustained over 24 h for GS-441514 and RDV.

1 April 2013 in Journal of Applied Animal Welfare Science
Verified
Journal Article
Closed access
EBEliza Bliss-Moreau
Eliza Bliss-Moreau
JTJacob H Theil
Jacob H Theil
GMGilda Moadab
Gilda Moadab
It is sometimes necessary for nonhuman primates to be restrained during biomedical and psychosocial research. Such restraint is often accomplished using a “primate chair.” The present paper details a method for training adult rhesus macaques to cooperate with a chair restraint procedure using positive and negative reinforcement. Successful training was accomplished rapidly in approximately 14 training days. The success of this training technique suggests that this method represents a refinement to traditional techniques despite the behavioral heterogeneity in the animal sample (which includes animals previously deemed unfit for traditional pole-and-collar training).

1 November 2022 in Journal of the American Association for Laboratory Animal Science
Verified
Journal Article
Closed access
ZHZoe Y Hsi
Zoe Y Hsi
JTJacob H Theil
Jacob H Theil
BMBetty W Ma
Betty W Ma
RORhonda S Oates
Rhonda S Oates
Rabbits are especially susceptible to adverse effects related to surgery, which can lead to inappetence and gastrointestinal (GI) stasis. However, these adverse effects may be related to discomfort from the procedure, anesthesia, the analgesics used, and the stress of restraint for analgesic administration. Opioid and NSAID analgesics which are frequently used in rabbits, can contribute to these adverse effects. This study compared the clinical GI side effects of buprenorphine and carprofen to saline controls in New Zealand White rabbits after a nonsurgical anesthetic event. Nine rabbits (3 females and 6 males, aged 8 to 20 mo) were randomly rotated through 5 treatment groups with a 7-d washout period between treatments: anesthesia control (no treatment), buprenorphine (0.05 mg/kg SC every 12 h for 72 h), carprofen (5 mg/kg SC every 24 h for 72 h), twice daily saline control (equivalent volume to buprenorphine SC every 12 h for 72 h), and once daily saline control (equivalent volume to carprofen SC every 24 h for 72 h). All rabbits were anesthetized 5 times and received initial treatments on the day of anesthesia. Generalized linear mixed models were used to assess food intake, water intake, and fecal output score for 7 days after anesthesia. Analysis showed that buprenorphine-treated rabbits had a significant 4-d decrease in food intake and a 3-d decrease in fecal output score compared with baseline. None of the other treatment groups showed any changes in food intake or fecal output score compared with baseline. These findings demonstrate that in the absence of pain, buprenorphine significantly depresses food intake in rabbits and that restraint and injections have minimal effect on food intake despite the possibility of increased stress.