Use of PCR-restriction fragment length polymorphism for the identification of zoonotic mycobacteriosis in zebrafish caused by Mycobacterium abscessus and Mycobacterium chelonae

Skin ulcers, scoliosis, and dropsy-like scale edema were observed in laboratory-maintained zebrafish. Affected fish had multifocal granulomas not only in internal organs such as the liver, intestine, genital organs, kidney, muscle, and spleen but also in the fin, epithelium, gills, and sclera of the eyes. Large numbers of acid-fast-rod-shaped bacteria were observed within the necrotic centers of well-demarcated, multifocal granulomas with Gram's stain and Ziehl-Neelson's stain. The size of the Mycobacterium spp. was 1-2 microm x 2-3 microm with a double-layered cell wall, based upon electron-microscopical features. Definitive diagnosis of these outbreaks was obtained by culture on selective media followed by PCR-restriction fragment length polymorphism analysis (PRA) of the rpoB gene for species identification. The amplified 360-bp products of the rpoB gene of mycobacteria isolated from zebrafish were digested with MspI restriction enzyme, which revealed unique band patterns matching those of Mycobacterium abscessus and Mycobacterium chelonae which are responsible for skin and soft tissue infection caused by rapidly growing mycobacteria in humans. This is the first documentation of the precise identification of zoonotic non-tuberculous mycobacteria isolated from laboratory-maintained zebrafish by the PRA of the rpoB gene; this study thus provides a great deal of useful epidemiological information and reduces the likelihood that epizootics will occur.     

Immunomodulatory effects of human amniotic membrane-derived mesenchymal stem cells

Human amniotic membrane-derived mesenchymal stem cells (hAM-MSCs) are capable of differentiating into several lineages and possess immunomodulatory properties. In this study, we investigated the soluble factor-mediated immunomodulatory effects of hAM-MSCs. Mitogen-induced peripheral blood mononuclear cell (PBMC) proliferation was suppressed by hAM-MSCs in a dose-dependent manner as well as hAM-MSC culture supernatant. Moreover, interferon-gamma and interleukin (IL)-17 production significantly decreased from PBMC, whereas IL-10 from PBMCs and transforming growth factor beta (TGF-β) production from hAM-MSCs significantly increased in co-cultures of hAM-MSCs and PBMCs. Production of several MSC factors, including hepatocyte growth factor (HGF), TGF-β, prostaglandin E2 (PGE2), and indoleamine 2, 3 dioxygenase (IDO), increased significantly in hAM-MSCs co-cultured with PBMCs. These results indicate that the immunomodulatory effects of hAM-MSCs may be associated with soluble factors (TGF-β, HGF, PGE2, and IDO), suggesting that hAM-MSCs may have potential clinical use in regenerative medicine.     

Effects of modified tall oil and vitamin E on growth performance,carcass characteristics,and meat quality of growing-finishing pigs

Crossbred barrows (n = 72) were used to evaluate effects of diet supplementation with modified tall oil (MTO; 0.0 or 0.50%) and vitamin E (0, 22, or 110 IU/kg) on growth performance, carcass traits, and longissimus muscle (LM) quality traits of finishing pigs. Pigs were blocked by ancestry and initial BW and allotted randomly to treatments in a 2 x 3 factorial. Corn-soybean meal-based diets were fed in two phases: 45.5 to 81.6 (1.00% lysine) and 81.6 to 114.6 (0.75% lysine) kg BW with no added fat. From 45.5 to 81.6 kg, pigs fed MTO had greater ADG (P = 0.03) regardless of added vitamin E; otherwise, treatment did not affect growth performance. Carcasses from pigs fed MTO had reduced (P < 0.05) average backfat (2.76 vs 2.92 cm) and firmer bellies compared to those fed no MTO. Boneless loins were cut into 2.54-cm chops at 7 d postmortem and evaluated for display color, thiobarbituric acid-reactive substance (TBARS), Warner-Bratzler shear force (WBSF), and sensory panel ratings. Visual color was similar (P > 0.05) among treatments at 0 and 1 d of display. At 4 and 6 d of display chops from pigs fed MTO with 110 IU vitamin E/kg had less deterioration (P < 0.05) than chops from pigs fed MTO with 0 IU vitamin E/kg and 0.0% MTO with 22 or 110 IU vitamin E/kg. The CIE L*, a*, b* and spectral values also suggested a delay in color deterioration for chops from pigs fed MTO with 110 IU vitamin E/kg. At 6 and 8 d of display, chops from pigs fed 110 IU vitamin E/kg had lower (P < 0.05) L* values than those from pigs fed 0 or 22 IU vitamin E/kg, and higher (P < 0.05) a* values than those from pigs fed 0 IU vitamin E/kg feed. A higher (P < 0.05) %R630/%R580 (indicator of more oxymyoglobin) was observed for chops from pigs fed MTO with 110 IU vitamin E/kg than those from pigs fed 0.0% MTO with 22 or 110 IU vitamin E/kg and MTO with 0 IU vitamin E/kg. Chops from pigs fed MTO with 110 IU vitamin E/kg had lower (P < 0.05) TBARS values than those from pigs fed MTO with 0 IU vitamin E/kg. No differences (P > 0.05) were detected among treatments for WBSF or sensory evaluations. The addition of MTO in swine diets improved belly firmness and reduced backfat, and feeding MTO with high levels of vitamin E extended display life without affecting palatability of LM chops.     

Analysis of the seroprevalence of bovine paratuberculosis and the application of modified absorbed ELISA to field sample testing in Korea

Paratuberculosis (PTB) is a major disease problem worldwide, and causes major economic losses in the dairy industry. Although PTB has been reported in Korea, no studies have been conducted to determine its prevalence and no program has been developed to control the disease. In this study, the sera of beef (n = 1,056) and dairy cattle (n = 1,105) from all provinces in Korea were tested to determine the prevalence of PTB using two different ELISA: an ''in house'' modified absorbed ELISA (P-ELISA) based on sonicated antigen from Mycobacterium avium subsp. paratuberculosis ATCC 19698, and a commercial ELISA (C-ELISA). Receiver operating characteristic analysis was used to determine the cutoff point for P-ELISA. Based on C-ELISA results, the area under the curve for P-ELISA was 0.913 (95% CI, 0.883 to 0.943). Using a cutoff point of 0.100, P-ELISA showed a sensitivity of 62.0% and a specificity of 93.7%. The kappa value and the percent agreement between the two ELISAs were 0.322 and 92.5%, respectively. Both ELISAs showed a significant correlation between age and seropositivity (p < 0.01). According to C-ELISA, 71 of 2,161 sera (3.3%, 95 CI, 2.6% to 4.1%) were test-positive. The national true prevalence of PTB was estimated to be 7.1%. The findings suggest that a control program should be implemented to limit the spread of this disease, and that P-ELISA could be used as a screening test that produces results similar to C-ELISA.     

Parvalbumin‐immunoreactive cells in the olfactory bulb of the pigeon: Comparison with the rat

The olfactory bulb (OB) shows special characteristics in its phylogenetic cortical structure and synaptic pattern. In the OB, gamma‐aminobutyric acid (GABA), as an inhibitory neurotransmitter, is secreted from GABAergic neurons which contain parvalbumin (a calcium‐binding protein). Many studies on the distribution of parvalbumin‐immunoreactive neurons in the rodent OB have been published but poorly reported in the avian OB. Therefore, in this study, we compared the structure of the OB and distribution of parvalbumin‐immunoreactive neurons in the OB between the rat and pigeon using cresyl violet staining and immunohistochemistry for parvalbumin, respectively. Fundamentally, the pigeon OB showed layers like those of the rat OB; however, some layers were not clear like in the rat OB. Parvalbumin‐immunoreactive neurons in the pigeon OB were predominantly distributed in the external plexiform layer like that in the rat OB; however, the neurons did not have long processes like those in the rat. Furthermore, parvalbumin‐immunoreactive fibres were abundant in some layers; this finding was not shown in the rat OB. In brief, parvalbumin‐immunoreactive neurons were found like those in the rat OB; however, parvalbumin‐immunoreactive fibres were significantly abundant in the pigeon OB compared to those in the rat OB.     

Treadmill exercise prevents diabetes-induced increases in lipid peroxidation and decreases in Cu,Zn-superoxide dismutase levels in the hippocampus of Zucker diabetic fatty rats

In the present study, we investigated the effects of treadmill exercise on lipid peroxidation and Cu,Zn-superoxide dismutase (SOD1) levels in the hippocampus of Zucker diabetic fatty (ZDF) rats and lean control rats (ZLC) during the onset of diabetes. At 7 weeks of age, ZLC and ZDF rats were either placed on a stationary treadmill or made to run for 1 h/day for 5 consecutive days at 16~22 m/min for 5 weeks. At 12 weeks of age, the ZDF rats had significantly higher blood glucose levels and body weight than the ZLC rats. In addition, malondialdehyde (MDA) levels in the hippocampus of the ZDF rats were significantly higher than those of the ZLC rats whereas SOD1 levels in the hippocampus of the ZDF rats were moderately decreased. Notably, treadmill exercise prevented the increase of blood glucose levels in ZDF rats. In addition, treadmill exercise significantly ameliorated changes in MDA and SOD1 levels in the hippocampus although SOD activity was not altered. These findings suggest that diabetes increases lipid peroxidation and decreases SOD1 levels, and treadmill exercise can mitigate diabetes-induced oxidative damage in the hippocampus.     

spa typing and enterotoxin gene profile of Staphylococcus aureus isolated from bovine raw milk in Korea

Staphylococcus aureus is a major etiological pathogen of bovine mastitis, which triggers significant economic losses in dairy herds worldwide. In this study, S. aureus strains isolated from the milk of cows suffering from mastitis in Korea were investigated by spa typing and staphylococcal enterotoxin (SE) gene profiling. Forty-four S. aureus strains were isolated from 26 farms in five provinces. All isolates grouped into five clusters and two singletons based on 14 spa types. Cluster 1 and 2 isolates comprised 38.6% and 36.4% of total isolates, respectively, which were distributed in more than four provinces. SE and SE-like toxin genes were detected in 34 (77.3%) isolates and the most frequently detected SE gene profile was seg, sei, selm, seln, and selo genes (16 isolates, 36.3%), which was comparable to one of the genomic islands, Type I νSaβ. This is a first report of spa types and the prevalence of the recently described SE and SE-like toxin genes among S. aureus isolates from bovine raw milk in Korea. Two predominant spa groups were distributed widely and recently described SE and SE-like toxin genes were detected frequently.     

Influence of Ovulation Status,Seasonality and Embryo Transfer Method on Development of Cloned Porcine Embryos

To improve pig cloning efficiency, the present study evaluated the effect of ovulation status, seasonality and embryo transfer (ET) method on in vivo development of cloned porcine embryos. Cloned embryos were transferred to surrogate mothers on the same day of somatic cell nuclear transfer. In pre‐ovulation stage (PO), pregnancy rate (PR) and delivery rate (DR) were 36.3% and 9.4%, respectively. In post‐ovulation stage, 22.7% PR and 2.1% DR were recorded (both PR and DR are significantly higher in PO). When ET was performed during winter (December–February), spring (March–May), summer (June–August) and autumn (September–November), the PRs were 13.4%, 37.3%, 24.6% and 51.0%, while DRs were 0%, 12.7%, 4.3% and 7.8%, respectively. The highest PRs were recorded in autumn groups. However, DRs were significantly lower in autumn (7.8%) group compared with spring (12.7%) group. The PR was the lowest and no piglets were born in winter group, which might be because of the effect of low temperature during ET. To overcome the low PR in winter group, 0.25 ml straws were used for ET to minimize exposure time of embryos to ambient temperature. The straw ET group showed significantly higher PR in the winter group (23. 9%) compared with the conventional catheter‐loading group (7.7%). We suggest that using PO recipient and ET in spring is the best condition for pig cloning. In addition, alternative method to reduce cold shock during ET in winter is necessary.     

Inoculation of seven pine species or hybrid seedlings with Korean isolates of pinewood nematode under greenhouse conditions

? Seedlings of seven pine species or hybrids, Pinus densiflora, Pinus thunbergii, Pinus virginiana, Pinus echinata, Pinus koraiensis, Pinus thunbergii × Pinus massoniana and Pinus × rigitaeda, were inoculated in a greenhouse with 100, 1 000 and 10 000 pathogenic nematodes, Bursaphelenchus xylophilus, to compare initial symptom development and to evaluate susceptibility to pinewood nematodes.

? Genetic types were significantly different in the starting day of needle discoloration (χ² = 43.48; P < 0.001) and the period from nematode inoculation to seedling death (χ² = 32.85; P > 0.001), but treatment groups were not statistically different in the days from inoculation to seedling death in any of the pine species.

? There was no relationship between seedling mortality and the number of nematodes recovered from infected seedlings. Only eight of the nematode-inoculated seedlings remained alive by day 83 after inoculation, including four seedlings each of P. echinata and P. × rigitaeda grown from bulked seed collections.

? Seedlings from the bulk lots were likely more genetically diverse than those from the single-source lots. A broader genetic representation of pine species or hybrids is suggested for screening for planting stocks resistant to B. xylophilus.