Glucocorticoid sensitivity depends on expression levels of glucocorticoid receptors in canine neoplastic mast cells

Glucocorticoid (GC) administration with or without other chemotherapeutic reagents is a commonly used option in the treatment of mast cell malignancies. However, the responsiveness of mast cell tumors to GC treatment varies in individuals, and the regulatory mechanisms determining the GC sensitivity of malignant mast cells remain unclear. Since the expression of the GC receptor (GR) has been reported to be associated with GC sensitivity in human neoplastic lymphocytes, we attempted to investigate the relationship between GR levels and GC sensitivity by using neoplastic mast cells derived from canine mast cell tumors (MCTs). To elucidate the regulatory mechanisms involved in GC responsiveness, we analyzed various canine MCT cell lines and tissue samples from dogs with MCT. While the proliferation of canine MCT cells was suppressed by the addition of GC to the culture, we found that MCT cells derived from humans and rodents, as well as canine lymphoma cells, responded poorly to GC. However, there were also some variations in responsiveness to GC treatment among canine MCT cell lines used in this study. Using real-time polymerase chain reaction and Western blot analysis, we elucidated the relationship between GR expression and responsiveness to GC in canine MCT cells. Furthermore, to assess the involvement of GR expression in GC sensitivity in vivo, clinical investigations were conducted on dogs with cutaneous MCT. Written informed consent was obtained from owners, and the affected dogs were treated with prednisolone (0.5-2.0 mg kg(-1)day(-1), administered orally) 1 or 2 weeks prior to the surgical removal of the tumors. Tumor volume was measured according to WHO criteria both before and after prednisolone treatment, and the GC sensitivity of each MCT was determined on the basis of the reduction in tumor volume. Of the 15 dogs with MCT, 11 responded to treatment with prednisolone completely or partially, whereas 4 dogs showed no response. Examination of clinical samples obtained by surgical removal revealed that GR expression levels were significantly lower in GC-resistant MCT tissues than in GC-sensitive MCT tissues. Thus, these results strongly indicate that GR expression may contribute to GC sensitivity in canine MCT.     

Associations between age of gilts at first mating and lifetime performance or culling risk in commercial herds

Age of gilts at first mating (AFM) is a factor associated with reproductive performance of female pigs. The objectives of the present study were to compare AFM and reproductive performance across parity between three herd groups based on a productivity measurement and to determine lifetime performance by AFM and the herd groups. The female data included 38,212 mated gilts entered between 2001 and 2003, and the herd data included mean measurements from 2001 to 2006 in 101 herds. The average female inventory of the 101 herds was 370.2 females. Females were categorized into five groups: AFM 188-208, 209-229, 230-250, 251-271 or 272-365 days. Three herd groups were formed on the basis of the upper and lower 25th percentiles of pigs weaned per mated female over six years: high-, intermediate- and low-performing herds. Multilevel mixed-effects models were performed to analyze comparisons. The AFMs (± SEM) in the high-, intermediate- and low-performing herds were 239.5 ± 0.22, 247.4 ± 0.21 and 256.7 ± 0.35 days, respectively. As the AFM increased from 209-229 to 272-365 days, annualized lifetime pigs born alive (PBA) decreased from 18.2 to 15.3 pigs, and the number of parities at removal decreased from 4.8 to 4.1 (P<0.05). In parity 1, females with an AFM of 209-229 days had fewer PBA, but had a lower culling risk and shorter weaning-to-first mating interval than those with an AFM of 251-271 days (P<0.05). In conclusion, we recommend management practices such as boar exposure to hasten puberty in gilts and decrease AFM.     

Basic biological characterization of feline morbillivirus

Feline morbillivirus (FmoPV) is an emerging virus that was recently discovered in domestic cats with chronic nephritis. Despite the potential role of FmoPV in chronic nephritis, little is known about its biological characteristics. In this study, we established a quantitative assay of FmoPV by using an indirect immunofluorescence technique. Viral titers of FmoPV were determined in one week. Treatment with polybrene^® or trypsin which was previously used in virus isolation did not augment the virus titers. FmoPV was notably stable at 4°C, retaining high titers for at least 12 days. Heat-treatment at 60°C and 70°C effectively inactivated FmoPV in 10 and 2 min, respectively. The biological characteristics of FmoPV reported here will be beneficial for establishing an efficient virus isolation method and will provide important information to take a measure to reduce the risk of FmoPV infection.     

Isolation of endophytic streptomycetes from above- and belowground organs of Quercus serrata

The occurrence and localization of endophytic actinomycetes within diverse organs of host plants provide ecological information that can be used to evaluate the significance of their spatial habitats. The aim of this study was to isolate and characterize endophytic actinomycetes in different organs of Quercus serrata. For this purpose, actinomycete isolates were obtained from surface-sterilized tissues of both symptomless seedlings and aged trees of Q. serrata and rhizosphere soil of the sampled seedlings. Thirty-five isolates with the ability to sporulate, including 4 from leaves of the aged trees, 10, 6, and 15 from leaves, stems, and roots of the seedlings, respectively, and 8 soil-derived isolates, were selected and characterized. The 16S rDNA nucleotide sequence analyses revealed that all of them belonged to the genus Streptomyces. According to a neighbor-joining phylogenetic tree constructed based on the results, the isolates of plant origin were divided into three major clades with high bootstrap values of 98 or 99 %, whereas eight soil-derived isolates were located at different positions from those of the endophyte isolates. Moreover, two larger clades were formed, one of which contained isolates derived only from aboveground parts, while the other contained isolates from all of the organs. These results suggest that the endophytic streptomycetes in Q. serrata may differ in their habitat positions (i.e., either above- or belowground parts).     

Downy mildew of busy lizzie caused by Plasmopara obducens in Japan

In June 2010 and March 2012, busy lizzie (Impatiens sultanii) plants in a glasshouse in Yamagata Prefecture and in nurseries in a plastic house in Shimane Prefecture, Japan were observed with yellowing of the adaxial surface of leaves or cotyledons and a white downy growth on the abaxial surface of leaves or cotyledons. We identified the causal pathogen as Plasmopara obducens based on the morphologies and rDNA-large subunit sequences. This new disease was named “downy mildew of busy lizzie” in Japan.     

Spawning grounds of red sea bream in the east Seto Inland Sea

We surveyed the distribution of red sea bream eggs between 2006 and 2010 in the east Seto Inland Sea to determine the location of the spawning grounds and the characteristics of preferred spawning habitats. We identified early-development stage red sea bream eggs using a monoclonal antibody assay. The early-development stage eggs were present in waters around Awaji Island (AW area) and around Ieshima Island, Shodo Island, and Bisan Seto (collectively the ISB area). The mean red sea bream egg density in the AW area was not significantly different from that in the ISB area. Based on the locations where we observed early-development stage eggs and the density of eggs, the ISB and AW areas appeared to be the primary spawning grounds in the east Seto Inland Sea during the survey period. A quotient analysis suggested that spawning fish had clear preferences for physical conditions. The areas suitable for spawning appear to be those with sandy substrate at a depth of 30–70 m. The temperature range suitable for spawning was between 16.5 and 21.5 °C.     

Utilization patterns of estuarine and marine habitats by the halfbeak Zenarchopterus dunckeri at Iriomote Island,southern Japan,evaluated from otolith microchemistry

Estuarine and marine habitat use patterns in the halfbeak Zenarchopterus dunckeri were examined at Iriomote Island, southern Japan, by analyzing otolith Li/Ca and Sr/Ca ratios. The ranges of both Li/Ca and Sr/Ca ratios in juvenile Z. dunckeri from the maximum (30 psu) to minimum (0.5 psu) salinity levels of brackish water estimated from rearing experiments, were compared with those of wild individuals collected from upstream and downstream stations in the Urauchi River estuary. The majority of wild-caught individuals had invariable Li/Ca and Sr/Ca ratios along an otolith transect from the core to the posterior edge, which fell within the otolith Li/Ca and Sr/Ca ranges estimated for estuarine individuals in the rearing experiments, suggesting that such individuals developed within the estuary without migrating to a marine environment at any time, although some downstream-dwelling fish had higher otolith elemental ratios than the predetermined estuarine ranges in the mid transect section. The latter fish may have been accidentally flushed from the estuary into the sea by heavy flood events, subsequently returning to the estuary. The overall results suggested that Z. dunckeri is essentially an estuarine resident, completing its life cycle within an estuarine system.