Distribution of Trichostrongylus colubriformis on common pasture grasses and legumes from the Midwestern United States

Nematodes that infect grazing herbivores rely on the ability of larvae to escape the fecal pat and ascend onto forage in order to be eaten by a subsequent host. However, pastures are polycultures of grasses and forbs that vary with respect to morphology and potential innate defense mechanisms acquired as part of their own co-evolution with nematode parasites. The objectives of this study were to 1) characterize the vertical distribution of Trichostrongylus colubriformis on a variety of plant species found in pastures in the Midwestern United States and 2) to identify plants that enhanced or inhibited larval ascent. Climbing assays were performed under greenhouse conditions whereby L3 were directly recovered from foliage. We found that at least 50% or more of the larvae were distributed on the first 2.5 cm closest to the soil surface for all plant species tested. In contrast, less than 10% of the larvae were distributed 12 cm or higher. For practical purposes, our findings agree with previous studies that suggest limiting grazing below a certain height to decrease parasite consumption. Further nuanced studies are needed to identify individual plant mechanical and chemical defenses that impact the ecology nematodes of veterinary importance.This article is published as Martin, Katy A., Jeba RJ Jesudoss Chelladurai, Christina Lavery, Rachel Shelangoski, Matthew Chaffee, and Matthew T. Brewer. "Distribution of Trichostrongylus colubriformis on common pasture grasses and legumes from the Midwestern United States." PloS one 20, no. 4 (2025): e0321367. doi: https://doi.org/10.1371/journal.pone.0321367

Perineal Urethrostomy Enables Susceptibility of Bull Calves as a Natural Host Model for Bovine Trichomonosis

Tritrichomonas foetus is a sexually transmitted protozoan that causes early embryonic death in cattle. A challenge in trichomonosis research is that in vivo studies of treatments, diagnostic strategies, and vaccines are severely hampered by the logistical challenge and cost of maintaining adult bulls. Since natural infections are diagnosed in postpubescent animals, the paradigm is that only mature breeding bulls can be infected. In this study, we hypothesized that prepubescent bull calves could be artificially infected with T. foetus trophozoites for the purpose of conducting research trials. Initial attempts to directly infect bull calves with two different parasite isolates resulted in the sporadic and transient detection of parasite DNA but not culturable trophozoites. In vitro and in vivo studies suggested that urine directly inhibited trophozoites, likely by osmotic damage and mechanical flushing action. Studies utilizing a perineal urethrostomy to remove urine flow from the prepuce resulted in the ability to colonize the prepuce, with live organisms being cultured for as long as 15 days post-inoculation. Future studies optimizing this technique have the potential to accelerate the pace of bovine trichomonosis research and may have applications in the study of human trichomoniasis.This article is published as Martin, Katy A., Jenna E. Bayne, Krystal Chinchilla-Vargas, Sara L. Reece, Jeba RJ Chelladurai, Tyler A. Harm, Jodi D. Smith, Courtney N. Blake, Douglas E. Jones, and Matthew T. Brewer. "Perineal Urethrostomy Enables Susceptibility of Bull Calves as a Natural Host Model for Bovine Trichomonosis." Microorganisms (2025). doi: https://doi.org/10.3390/microorganisms13051070

Infection of prepubertal heifer calves as a natural host model for Tritrichomonas foetus

IntroductionTritrichomonas foetus is a sexually transmitted flagellate that causes economic loss in the cattle industry throughout the world. In the United States, there are no approved treatments for the parasite. Owing to its transmission strategy, T. foetus typically infects cattle of breeding age. However, in vivo studies of treatment, diagnostic strategies, and vaccination are severely hampered by the maintenance and cost of maintaining adult cattle in research settings. In this study, we investigated the utility of infecting pre-pubescent heifer calves with T. foetus.MethodsFour independent cohorts of cross-bred prepubertal heifer calves were vaginally inoculated with T. foetus trophozoites previously derived from a naturally-infected bull. Infections were assessed by culture, PCR, DNA sequencing, histopathology, gross pathology, and lesion scoring. In addition, reproductive tract tissue was assessed for the presence of galectin-1, a putative receptor for T. foetus trophozoite adhesion.ResultsOur experiments revealed that despite being in anestrus, heifer calves were amenable to infection with trophozoites for as long as 42 days post-infection as determined by PCR and culture of the organism. Histopathology revealed inflammation throughout the reproductive tract of infected calves. Infection resulted in endometritis with lymphoplasmacytic infiltration and demonstrated that trophozoites could pass through the cervix even during anestrus in prepubescent heifers. In addition, immunohistochemistry of the vagina, cervix, and uterus demonstrated robust expression of galectin-1.ConclusionOur experiments demonstrated that prepubertal heifer calves are a suitable natural host model for bovine trichomonosis. This is a significant breakthrough in the field and also has potential for advancing the human trichomoniasis research agenda

Drama and discounting in the relational dynamics of corporate social responsibility

Employing theoretical resources from Transactional Analysis (TA) and drawing from interviews with managers dealing with social or environmental issues in their role, we explain how CSR activity provides a context for dramas in which actors may ignore, or discount aspects of self, others, and the contexts of their work as they maintain and reproduce the roles of Rescuers, Persecutors and Victims. In doing so, we add to knowledge about CSR by providing an explanation for how the contradictions of CSR are avoided in practice even when actors may be aware of them. Specifically, we theorise how CSR work can produce dramatic stories where adversity is apparently overcome, whilst little is actually achieved at the social level. We also add to the range of psychoanalytic tools used to account for organisational behaviours, emphasising how TA can explain the relational dynamics of CSR

Improved magnetization in sputtered dysprosium thin films

50nm thick nanogranular polycrystalline dysprosium thin films have been prepared via ultra-high vacuum DC sputtering on SiO2 and Si wafers. The maximum in-plane spontaneous magnetization at T = 4K was found to be MS4K = 3.28T for samples deposited on wafers heated to 350C with a Neel point of TN = 173K and a ferromagnetic transition at TC = 80K, measured via zero field cooled field cooled magnetization measurements, close to single crystal values. The slightly reduced magnetization is explained in the light of a metastable face centered cubic crystal phase which occurred at the seed interface and granularity related effects, that are still noticeably influential despite an in-plane magnetic easy axis. As deposited samples showed reduced magnetization of MS4K = 2.26T, however their ferromagnetic transition shifted to a much higher temperature of TC = 172K and the antiferromagnetic phase was completely suppressed probably as a result of strain.Comment: 16 pages, 3 figure

Finite Element Model Based Warning Device to Prevent Electrical Hazard

AbstractConstruction workers suffer the most electrocutions among all industries. Major reasons for electrocution in the construction industries are workers contact with the power line or material handling equipment contact with the power line. To prevent the electrical accidents, in the construction or any other industry there is a need for warning devices. Since, there is no electrical contact warning devices available in the market, two different types of warning devices are proposed in the present work for the safety of human workers and equipments. Computer modeling is done in ANSYS to simulate human wrist in electrical proximity and electrical contact conditions. For the prevention of equipment related accidents, a low cost warning device has been developed using IC CD 4033. Warning device for the worker is envisaged by using elastic conductive cuffs around the wrist of the worker. Since, human wrist is analogous to hog leg, several experiments were conducted using hog leg specimen. To amplify the voltage across the pair of cuff fixed in the hog leg specimen an instrumentation amplifier is designed and developed