Mapping the global interactome of the ARF family reveals spatial organization in cellular signaling pathways

The ADP-ribosylation factors (ARFs) and ARF-like (ARLs) GTPases serve as essential molecular switches governing a wide array of cellular processes. In this study, we utilized proximity-dependent biotin identification (BioID) to comprehensively map the interactome of 28 out of 29 ARF and ARL proteins in two cellular models. Through this approach, we identified ~3000 high-confidence proximal interactors, enabling us to assign subcellular localizations to the family members. Notably, we uncovered previously undefined localizations for ARL4D and ARL10. Clustering analyses further exposed the distinctiveness of the interactors identified with these two GTPases. We also reveal that the expression of the understudied member ARL14 is confined to the stomach and intestines. We identified phospholipase D1 (PLD1) and the ESCPE-1 complex, more precisely SNX1, as proximity interactors. Functional assays demonstrated that ARL14 can activate PLD1 in cellulo and is involved in cargo trafficking via the ESCPE-1 complex. Overall, the BioID data generated in this study provide a valuable resource for dissecting the complexities of ARF and ARL spatial organization and signaling.

PTP-PEST couples membrane protrusion and tail retraction via VAV2 and p190RhoGAP

Cell motility is regulated by a balance between forward protrusion and tail retraction. These phenomena are controlled by a spatial asymmetry in signals at the front and the back of the cell. We show here that the protein-tyrosine phosphatase, PTP-PEST, is required for the coupling of protrusion and retraction during cell migration. PTP-PEST null fibroblasts, which are blocked in migration, exhibit exaggerated protrusions at the leading edge and long, unretracted tails in the rear. This altered morphology is accompanied by changes in the activity of Rho GTPases, Rac1 and RhoA, which mediate protrusion and retraction, respectively. PTP-PEST null cells exhibit enhanced Rac1 activity and decreased RhoA activity. We further show that PTP-PEST directly targets the upstream regulators of Rac1 and RhoA, VAV2 and p190RhoGAP. Moreover, we demonstrate that the activities of VAV2 and p190RhoGAP are regulated by PTP-PEST. Finally, we present evidence indicating the VAV2 can be regulated by integrin-mediated adhesion. These data suggest that PTP-PEST couples protrusion and retraction by acting on VAV2 and p190RhoGAP to reciprocally modulate the activity of Rac1 and RhoA.

Effectiveness of oxibendazole against benzimidazole-resistant strongyles in horses

Twenty-eight horses with a residual burden of strongyle eggs in the faces after treatment with mebendazole (MBZ) paste were treated with a suspension of either MBZ or oxibendazole (OBZ). Fecal samples were collected before and 14 days after these treatments. The number of strongyle eggs/g (epg) of feces for each horse was estimated using the Cornell-McMaster dilution and the Cornell-Wisconsin double centrifugation procedures. The epg for each horse was transformed using log (x + 1) and in an analysis of variance of the reduction in egg count for each horse on the logarithmic scale, there was a highly significant difference between the treatments. The mean epg was increased in the MBZ-treated horses and reduced in the OBZ-treated horses, but the reduction was only by 82% with an upper confidence limit of 89%. Subsequently, the horses were retreated with MBZ and OBZ suspensions without significant reduction in the mean epg for OBZ-treated horses.

Effectiveness of an ivermectin liquid formulation given by nasogastric tube against strongyles in horses

Twenty horses were treated with ivermectin either by nasogastric tube with a liquid formulation for sheep or per os with a paste formulation for horses at a dosage of 200 mug/kg of body weight. Fecal samples were collected from these horses and from ten untreated horses at the time of treatment and every 2 wk thereafter for up to 10 wk. The samples were examined for nematode eggs using the Cornell-McMaster dilution and the Cornell-Wisconsin Double Centrifugation procedures.There were no signs of toxicosis in horses treated with ivermectin. Strongyle eggs were found in the feces of all horses before treatment. Subsequently, they were found in untreated horses, but not in treated horses at 2 wk nor in most of them for up to 8 wk after treatment. At 10 wk most of these horses had strongyle eggs in their feces, but in general fewer than at pretreatment.

Effectiveness of ivermectin paste for removal of nematodes in the horse

Thirteen Standardbred horses, two to five years of age, were treated with ivermectin paste per os at 200 mug/kg of body weight and 13 were untreated. Two weeks after treatment, previously untreated horses were given the paste. Fecal samples were collected from all horses at the time of treatment and periodically thereafter up to 14 weeks and were examined for nematode eggs using the Cornell-McMaster dilution and the Cornell-Wisconsin double centrifugation procedures.All horses consumed the paste readily and had no signs of toxicosis. Strongyle eggs were found in the feces of all horses before treatment but not at two to three weeks after treatment. At five to six weeks after treatment only two horses had eggs in the feces. At eight, ten, 12 and 14 weeks after treatment 27, 69, 88 and 100% of the horses examined, respectively, had a few strongyle eggs but these were no greater than 18% of that of the pretreatment samples. Ivermectin oral paste, therefore, appeared to be highly effective against both adult and immature strongyles.

Reproductive performance in dairy cows following postpartum treatment with gonadotrophin releasing hormone and/or prostaglandin: a field trial

Three hundred and five Holstein Friesian cows were given either 250 micrograms gonadotrophin releasing hormone (GnRH) or saline on day 15 postpartum followed by 500 micrograms cloprostenol or saline on day 24 postpartum. Four treatment groups were formed using random allocation: Group I -- placebo (Day 15)/placebo (Day 24), Group II -- GnRH (Day 15)/placebo (Day 24), Group III -- placebo (Day 15)/cloprostenol (Day 24), Group IV -- GnRH (Day 15)/cloprostenol (Day 24). Double blind techniques were used during the follow-up period. Rectal palpation, to assess uterine involution and ovarian activity was performed just prior to each treatment and again at 28 days postpartum. In addition blood samples were collected at 15, 24 and 28 days postpartum for measurement of plasma progesterone. There were no significant differences among treatment groups with respect to services per conception, number of heats detected before first service and culling for infertility. Cows treated only with GnRH had an increased calving to first estrus and calving to first breeding interval, and tended to have an increased calving to conception interval. Treatment with cloprostenol significantly decreased calving to conception and calving to first observed estrus intervals. Treatment with GnRH on day 15 postpartum resulted in a significant increase in the subsequent incidence of pyometra and prebreeding anestrus. On the other hand, cloprostenol treatment on day 24 postpartum resulted in a decreased incidence of pyometra, regardless of GnRH treatment and a decreased incidence of prebreeding anestrus in GnRH treated cows compared to cows receiving only GnRH at day 15 postpartum.(ABSTRACT TRUNCATED AT 250 WORDS)

Twenty years of experience with dairy herd health in Ontario

This article expresses observations on planned herd health for dairy cattle, based on experience gained in the Ambulatory Clinic practice of the Ontario Veterinary College. The author and his colleagues, especially Dr. R.A. Curtis, have initiated and delivered a preventive medicine approach to veterinary practice in the teaching program and teaching practice for the past 20 years. In addition, herd health presentations have been made to veterinary associations in every province in Canada and to many breed associations and producer organizations. The Canadian food animal veterinarian and his clients have been informed at meetings and by the media of the need, objectives, methods and benefits of dairy herd health and many veterinary practices now offer programs to their clients. Herd health has become a household word in Canada's dairy practices and dairy farms.A formal herd health program is an important step to achieving total health management; but maximum returns on investment can only be realized after three or four generations of cattle have been reared on the program. In conclusion, herd health practice has been a very satisfying aspect of veterinary medicine and a profitable and valued service for our clients. Maintenance of health involves the application of all knowledge and procedures which veterinarians have to offer.

The effect of retained placenta and metritis complex on reproductive performance in dairy cattle -- a case control study

A study of the computer stored records of 293 dairy cows and 652 calvings reveals the effects of retained placenta and metritis complex on reproductive performance. The overall incidence rate of retained placenta was 11.2%. Retained placenta was 4.6 times more likely to occur following twin births than following single births. Most cases of retained placenta occurred during the fall. Forty-five percent of that seasonal increase was explained by an increased number of calvings. Metritis complex was diagnosed following 54.8% of retained placenta cases. Retained placenta alone did not significantly impair reproductive performance. Metritis complex, in the presence or absence of retained placenta, caused a significant (P</=0.05) increase in days open, services per conception, calving to first heat intervals and days from calving to first service. There is an indication (interaction P</=0.1) that cows with both retained placenta and metritis complex are more severely affected than cows with either retained placenta or metritis complex alone. The influence of retained placenta on fertility appears to depend on the proportion of cows with retained placenta that have metritis complex.