Molecular characteristics of horse phospholipase C zeta (PLCζ)

A sperm‐specific phospholipase C (PLC), PLCzeta (PLCζ), is thought to underlie the initiation of calcium ([Ca²⁺]_i) oscillations that induce egg activation in mammals. In large domestic species, only bovine, porcine and recently equine PLCζ have been cloned, and the physiological functions of these molecules have not been fully characterized. Here, we evaluated the physiological functions of equine PLCζ (ePLCζ) in mouse oocytes. ePLCζ was cloned from testis using RT‐PCR. The expression of ePLCζ messenger RNA was confirmed in testis but not in other tissues. Microinjection of ePLCζ complementary RNA (cRNA) into mouse oocytes induced long‐lasting [Ca²⁺]_i oscillations, and most of the injected oocytes formed pronuclei (PN). The injection of cRNAs encoding horse, mouse, human and cow PLCζ into mouse oocytes showed that ePLCζ had the highest [Ca²⁺]_i oscillation‐inducing activity among the species tested. Mutation of D202R, which renders the protein inactive, abrogated the activity of ePLCζ. The nuclear translocation ability of ePLCζ was defective when expressed in mouse oocytes. Taken together, our findings show for the first time that ePLCζ has highest activity of the mammalian species studied to date. Our findings will be useful for the improvement of reproductive technologies in the horse.     

Epidermoid cyst of the ileum in a miniature dachshund dog

A 13-year-old castrated male miniature dachshund dog was presented with chronic vomiting and diarrhea. Contrast radiography and surgical exploration revealed an ileal cyst, which was excised. A diagnosis of epidermoid cyst was made from a combination of the clinical findings and histological examination of the surgical specimen.     

Adsorption effect of activated charcoal on enterohemorrhagic Escherichia coli

The adsorption property of activated charcoal on verotoxin (VT)-producing Escherichia coli (VTEC) was examined using E. coli O157:H7. In the present study, E. coli O157:H7 strains were effectively adsorbed by activated charcoal. Adsorption was dose-dependent, and the maximum adsorption occurred within 5 min. At 10 mg of activated charcoal, bacteria tested were completely adsorbed. Activated charcoal also had the capacity to adsorb toxin (verotoxin 2) activity from the bacterial extract. Furthermore, the adsorption efficiency of activated charcoal for the normal bacterial flora in the intestine was assessed using Enterococcus faecium, Bifidobacterium thermophilum, and Lactobacillus acidophilus. Activated charcoal showed lower binding capacity to the normal bacterial flora tested than that to E. coli O157:H7 strains. These results suggest that activated charcoal could be a good adsorbent system for the removal of VTEC and verotoxin.     

Development of Babesia gibsoni in the midgut of larval tick, Rhipicephalus sanguineus.

Studies were made on the development of Babesia gibsoni in the midgut of the larval tick, Rhipicephalus sanguineus. Six hr after repletion, merozoites of B. gibsoni, freed from erythrocytes, were observed in the midgut contents of the tick. After that, within 24 hr, those merozoites were transformed into the ring-forms which were relatively large, 2-3 microns in diameter. Later, the ring forms developed into the spherical forms which were subelliptical in shape and 4-6 microns in diameter. Within 2-4 days, the elongated forms, 5-8 microns in length, were found. At this time, some of the binucleated fusion form has assumed a form intermediate between the spherical and elongated-forms. About 5-6 days after repletion, large round or elliptic zygotes, 8-10 microns in diameter, were observed in the tick gut.     

Evaluation of inbreeding and genetic diversity in Japanese Shorthorn cattle by pedigree analysis

The Japanese Shorthorn is a Japanese Wagyu breed maintained at a small population size. We assessed the degree of inbreeding and genetic diversity among Japanese Shorthorn cattle using pedigree analysis. We analyzed the pedigree records of registered Japanese Shorthorn born between 1980 and 2018, after evaluating the pedigree completeness. The average of the actual inbreeding coefficients increased at the same rates annually from approximately 1.5% in 1980 to 4.2% in 2018 and was higher than the expected inbreeding coefficients over time. The effective population size based on the individual coancestry rate largely decreased from 127.8 in 1980 to 82.6 in 1999, and then remained almost constant at approximately 90. Three effective numbers of ancestors decreased over time until 1995, then remained almost constant. In particular, the effective number of founder genomes (N_ge) decreased from 43.8 in 1980 to 11.9 in 2018. The index of genetic diversity based on N_ge decreased from 0.99 in 1980 to 0.96 in 2018 due to genetic drift in non-founder generations. Changes in inbreeding and genetic diversity parameters were similar between Japanese Shorthorn and other Japanese Wagyu breeds, but the magnitude of the changes was lower in the Japanese Shorthorn.     

Equine nonneoplastic abnormal ovary in a draft mare with high serum anti-Müllerian hormone: a case study

We performed a standing hand-assisted laparoscopic ovariectomy in a draft mare that presented with high serum anti-Müllerian hormone (AMH) level and had an enlarged single cystic ovary. Histopathological examination revealed no tumor cell proliferation in the ovary, but the presence of a large ovarian cyst was confirmed. In the diagnosis of abnormal ovaries in mares, a comprehensive assessment should be performed, including the monitoring of ovarian morphology and biomarkers over time, to determine the disease prognosis and treatment plan. The case of this mare with a nonneoplastic abnormal ovary and increased serum AMH level was rare. We suggest that standing hand-assisted laparoscopic ovariectomy is useful for the removal of large ovaries in draft mares.     

Abnormal development of nephrons in claudin-16-defective Japanese black cattle

The kidneys of 37 Japanese Black calves aged 2 to 65 months diagnosed with Claudin 16 (CL-16) defect by the DNA-based test were examined pathologically. The animals exhibited clinical symptoms such as growth impairment, renal failure, overgrowth of hooves, and anemia at a young age. There was no correlation between the time of onset and age. Kidney weights relative to body weight were similar to those in normal animals, but both kidney net weights and size were reduced due to atrophy in animals that showed severe renal dysfunction. Histopathological examination of the kidneys showed reduction in the number of glomeruli, compensatory hypertrophy of glomeruli and tubules, and glomerular and tubular atrophy accompanied by interstitial fibrosis and lymphocytic infiltration. Glomeruli were clearly less in number in the kidneys of CL-16-defective animals than those of normal animals even in the cases with mild lesions. A small number of immature glomeruli and tubules were also detected, suggesting that there were fewer nephrons developed at birth in CL-16-defective animals. It was suggested that a defect of the CL-16 gene is involved in the "abnormal development of nephrons". Immunohistopathological examination of the kidneys showed that the epithelium of thick ascending limb of Henle was stained with anti-CL-16 antibody in the control animals, but not in the affected animals, suggesting a defect of CL-16 in the epithelium of renal tubules in the affected animals.     

Cardiopulmonary bypass influences the plasma levels of calcitonin gene-related peptides in dogs: effects of hemofiltration and hemodilution

Calcitonin gene-related peptides (CGRP), which are potent vasodilators, are elevated during cardiopulmonary bypass (CPB) in humans. We evaluated the plasma levels of CGRP in dogs during CPB with hemofiltration with and without hemodilution. Female beagles were divided into control (n=5) and hemodilution (n=5) groups. The CPB with hemofiltration was performed with or without hemodilution. For the measurement of CGRP, blood samples were collected pre-CPB, during CPB, and post-CPB. The concentrations of CGRP in the hemofiltration solution were measured. Although the CPB elevated the plasma CGRP levels in both groups, its elevation was significant in the hemodilution group when compared to the pre-CPB levels. CGRP levels returned to normal post-CPB. Significant differences were found between the two groups in the CGRP amount in hemofiltration. The results show that hemofiltration should be used during CPB to decrease the plasma levels of CGRP.