Transplacental infection of porcine fetuses following experimental challenge inoculation with encephalomyocarditis virus.

Ten multiparous sows were inoculated between 46 and 50 days of gestation with a fetal swine isolate of encephalomyocarditis virus (EMCV) to investigate the ability of the virus to cause transplacental infection and fetal death. Four sows (group 1) were inoculated IM with EMCV MN-25 that had been passaged 4 times on baby hamster kidney-21 line cell monolayers. Two sows were euthanatized at postinoculation (PI) day 23, and the other 2 sows at PI day 44. An additional 6 sows (group 2) were inoculated IM with the same virus that had been passaged 5 additional times in pigs. Two sows were euthanatized at 14 days, and the remaining 4 sows at PI day 28. Clinical signs were not observed in any of the sows, whereas all sows seroconverted to EMCV. In group 1, only 2 of 50 fetuses were mummified. Virus was not recovered, although EMCV antibodies were detected in the 2 mummified fetuses. In group 2, the 2 sows that were euthanatized at PI day 14 had 26 normal fetuses and there was no evidence of fetal infection. However, in the 4 sows euthanatized at PI day 28, 20 of 48 fetuses were mummified, hemorrhagic, or edematous. Encephalomyocarditis virus was recovered from 21 of 48 fetuses. Transplacental infection and fetal deaths in pregnant sows was achieved following infection with EMCV passaged in pigs.     

Changes in orexin-A and neuropeptide y expression in the hypothalamus of obese and lean Zucker Diabetic Fatty rats

This study was carried out to investigate the changes of orexin-A (OXA) and neuropeptide Y (NPY) expression in the hypothalamus of the obese and lean Zucker Diabetic Fatty (ZDF) rats which have a missense mutation in the leptin receptor gene. The mean body weights (MBW) between the obese and lean ZDF rats were significantly different at 28 and 70 postnatal days. However, at 14 postnatal day, there was no significant difference in the MBW between the obese and lean ZDF rats in both male and female. The OXA immunoreactivities were not significantly different between the obese and lean ZDF rats in both sexes at 14, 28, and 70 postnatal days, respectively. The NPY immunoreactivity was higher in the obese than in the lean ZDF rats in both male and female at 28 and 70 postnatal days, whereas there was no significant difference between the obese and lean ZDF rats at 14 postnatal day. These results indicate that both OXA and NPY might halt their roles for food intake in the obese phenotype of the male and female ZDF rats in the preweaning period of 14 postnatal day, whereas NPY might play a main role in the obesity of these rats in the weaning period of 28 and 70 postnatal days.     

The environmental safety of eprinomectin to earthworms

A study was conducted to assess the environmental safety of the endectocide eprinomectin to the earthworm Lumbricus terrestris under conditions mimicking typical product use on pasture. The LC50 value of eprinomectin in artificial soil after 28 days of exposure is higher than the levels expected in feces from dosed cattle or in soil fertilized with manure from dosed cattle, which indicates a wide margin of safety for this compound to earthworms. However, the no-observed-effect concentration has not been established. Therefore, the current study was conducted to determine whether there would be any effects on earthworms from feces from cattle treated with the commercial formulation of eprinomectin. Feces were collected rectally from grazing cattle on Day 0 before treatment and on Days 2, 4, 7 and 14 after treatment with EPRINEX (eprinomectin) Pour-On for Beef and Dairy Cattle (Merial Limited) at 0.5 mg eprinomectin per kg bodyweight. Assays of eprinomectin B1a (the major component of eprinomectin) were 0, 0.427, 0.152, 0.0512 and 0.00185 mg kg-1 wet weight of feces (equivalent to 0, 3.34, 1.19, 0.40 and 0.010 mg kg-1 on a dry weight basis, respectively). No significant differences (p>0.05) were observed at any day post-treatment in the survival or behavioral effects of any worms fed post-dose feces relative to the worms fed control feces. All post-dose comparisons of weight changes of living earthworms to the control group were not significantly different (p>0.05), indicating that treatment of cattle with EPRINEX (eprinomectin) Pour-On for Beef and Dairy Cattle did not affect feeding or weight gain of the earthworms. The LC50 value and the results of this study establish the wide margin of safety afforded to earthworms by eprinomectin under typical usage conditions.     

Preferential expression of L-type amino acid transporter 1 in ameloblasts during rat tooth development

Certain amino acid transport systems play an important role in supplying organic nutrients to each cell and for cell proliferation during tooth development. However, the mechanisms responsible for such actions are unclear. This study demonstrated for the first time that LAT1 and 4F2hc are expressed during tooth development in prenatal and postnatal rats, and that the transporters show cell-specific expression in ameloblasts, which are the epithelium-derived dental cells. LAT1 and 4F2hc expression was not observed in other dental cells of the developing teeth such as odontoblasts and cementoblasts. Overall, these results suggest that LAT1 and 4F2hc might play an important role in enamel formation.     

Monoclonal antibody analysis of porcine reproductive and respiratory syndrome virus epitopes associated with antibody-dependent enhancement and neutralization of virus infection

Enhanced infection and replication of porcine reproductive and respiratory syndrome (PRRS) virus in the presence of specific antibody has been demonstrated in vitro and in vivo, a phenomenon known as antibody-dependent enhancement (ADE). ADE is considered to be a significant obstacle to developing effective vaccines for many viruses for which ADE has been reported, since virus-specific antibodies of maternal origin or those conferred by vaccination can facilitate the entry of the virus into target cells, sometimes resulting in increased severity of the disease. In this study, the role of specific PRRS viral epitopes in ADE and/or virus neutralization (VN) was assessed in vitro using 14 monoclonal antibodies (mAbs) to 4 PRRS viral proteins: nucleocapsid (N), matrix (M), glycoprotein (GP) 5, and GP3. Each mAb recognized a distinct epitope on one of these proteins. One-way ADE and VN assays were performed in vitro using homologous PRRS virus isolates in the presence or absence of each mAb. ADE activity was determined by detecting a significant increase of progeny virus yield in porcine alveolar macrophage cultures in the presence of individual mAbs. Neutralizing activity was determined by detecting a significant reduction or complete blocking of virus replication in MARC-145 cells in the presence of individual mAbs. mAbs could be categorized into 3 groups: enhancing, neutralizing and neither. Viral epitopes which are capable of inducing neutralizing antibodies appeared to reside on the M, GP3 and GP5 proteins, while epitopes that may induce ADE-mediating antibody were associated with the N and GP5 proteins. Identification of the viral proteins and antigens and epitopes responsible for ADE- and VN-mediating antibodies may provide the basis for developing efficacious second-generation vaccines for the control of PRRS virus; yet, further epitope mapping remains to be done.     

Impaired control of IRES-mediated translation in X-linked dyskeratosis congenita

The DKC1 gene encodes a pseudouridine synthase that modifies ribosomal RNA (rRNA). DKC1 is mutated in people with X-linked dyskeratosis congenita (X-DC), a disease characterized by bone marrow failure, skin abnormalities, and increased susceptibility to cancer. How alterations in ribosome modification might lead to cancer and other features of the disease remains unknown. Using an unbiased proteomics strategy, we discovered a specific defect in IRES (internal ribosome entry site)-dependent translation in Dkc1(m) mice and in cells from X-DC patients. This defect results in impaired translation of messenger RNAs containing IRES elements, including those encoding the tumor suppressor p27(Kip1) and the antiapoptotic factors Bcl-xL and XIAP (X-linked Inhibitor of Apoptosis Protein). Moreover, Dkc1(m) ribosomes were unable to direct translation from IRES elements present in viral messenger RNAs. These findings reveal a potential mechanism by which defective ribosome activity leads to disease and cancer.     

Comparative effects of organic and inorganic selenium on selenium transfer from sows to nursing pigs

To investigate the effects of supplemental Se on the transfer of Se to nursing pigs when sows are fed diets containing a Se level above the NRC recommendation (0.15 ppm), sows were fed diets containing no supplemental Se or supplemental (0.3 ppm) Se from sodium selenite or Se yeast. A nonSe-fortified corn-soybean meal basal diet with a high endogenous Se content served as the negative control (0.20 to 0.23 ppm Se). Fifty-two sows were fed diets from 60 d prepartum until 14 d of lactation. Six sows per treatment were bled at 60 and 30 d prepartum, at farrowing, and at 14 d postpartum to measure serum Se concentrations. Colostrum was collected within 12 h postpartum, and milk was collected at 14 d of lactation. Blood was obtained from 3 pigs each from 12 litters per treatment at birth and at weaning (d 14), and pooled serum was analyzed for Se and immunoglobulin G concentrations and glutathione peroxidase activity. Regardless of treatment, serum Se in sows declined throughout gestation and gradually increased during lactation. Sows fed Se yeast tended (P < 0.06) to have greater serum Se at farrowing than sows fed unsupplemented diets. Colostrum and milk (d 14) Se concentrations increased (P < 0.01) when sows were fed Se from yeast but not from sodium selenite. At birth, serum Se was increased (P < 0.01) for pigs whose dams were fed Se yeast compared with pigs from sows fed the basal diet. At 14 d of age, there was no difference in serum Se concentration of pigs from dams fed any of the treatments. Pig serum immunoglobulin G concentrations and glutathione peroxidase-1 activity were unaffected by dietary Se source. Supplementation of gestating and lactating sow diets with Se (0.3 ppm) from an organic or inorganic source reduced the number of stillbirths per litter. However, only pigs born to sows fed organic Se (Se yeast) had greater serum Se at birth. Organic Se increased Se concentration of colostrum and 14-d milk to a greater degree than inorganic Se.     

Comparative analysis of pathogenesis-related protein 10 (<Emphasis Type="Italic">PR10</Emphasis>) genes between fungal resistant and susceptible peppers

To elucidate the functional roles of PR10 genes from two pepper species during plant-pathogen interactions, PR10 genes were isolated from fungal-resistant (Capsicum baccatum var. PBC80) and fungal-susceptible (C. annuum var. Yeoju) pepper fruits infected with anthracnose fungus (Colletotrichum acutatum). Despite strong nucleotide sequence identity, there were significant differences in the patterns of gene expression and protein accumulation between the genes from the two host species. Induced expression of the PR10 mRNA in PBC80 (bacPR10) was highly maintained from 24 h after infection (HAI) rather than that in Yeoju (annPR10). These mRNA expression patterns were correlated with the level of respective protein that was detected as two or three bands in each species. Substantial induction of bacPR10 proteins was confirmed by 2D-gel analysis followed by immunoblotting. Immunolocalization study showed that deposition of bacPR10 was exclusively observed in the pericarp of PBC80 fruits after fungal infection, suggesting functional significance in defence. Additionally, in vitro analysis of the enzymatic properties of PR10 proteins revealed that recombinant bacPR10 had higher ribonucleolytic activity and exhibited less sensitivity to proteinase treatment than did annPR10. Taken together, these results support the idea that relative abundance and prolonged longevity of bacPR10 in PBC80 fruits may contribute to their increased resistance in response to the anthracnose fungus, as compared with Yeoju fruit.