Aberrant CpG methylation of the imprinting control region KvDMR1 detected in assisted reproductive technology-produced calves and pathogenesis of large offspring syndrome

Although somatic cell nuclear transfer (NT) and in vitro fertilization (IVF) have the potential to produce genetically superior livestock, considerable numbers of abnormally large animals, including sheep and cattle affected by "large offspring syndrome" (LOS), have been produced by these assisted reproductive technologies (ART). Interestingly, these phenotypes are reminiscent of Beckwith-Wiedemann syndrome (BWS) in humans, which is an imprinting disorder characterized by pre- and/or postnatal overgrowth. The imprinting control region KvDMR1, which regulates the coordinated expression of growth control genes such as Cdkn1c, is known to be aberrantly hypomethylated in BWS. Therefore, we hypothesized that aberrant imprinting in this region could contribute to LOS. In this study, we analyzed the DNA methylation status of the Kcnq1ot1/Cdkn1c and Igf2/H19 domains on bovine chromosome 29 and examined the coordinated expression of imprinted genes surrounding them in seven calves derived by NT (which showed signs of developmental abnormality), two calves conceived by IVF (both developmentally abnormal), and three conventional calves that died of unrelated causes. Abnormal hypomethylation status at an imprinting control region of Kcnq1ot1/Cdkn1c domain was observed in two of seven NT-derived calves and one of two IVF-derived calves in almost all organs. Moreover, increased expression of Kcnq1ot1 and diminished expression of Cdkn1c were observed by RT-PCR analysis. This study is the first to describe the abnormal hypomethylation of the KvDMR1 domain and subsequent changes in the gene expression of Kcnq1ot1 and Cdkn1c in a subset of calves produced by ART. Our findings provide strong evidence for a role of altered imprinting control in the development of LOS in bovines.     

Dosing-time dependent effect of dexamethasone on bone density in rats

AimsWhile glucocorticoids are widely used to treat patients with various diseases, they often cause adverse effects such as bone fractures. In this study, we investigated whether the decrease in bone density induced by glucocorticoid therapy was ameliorated by optimizing a dosing-time.Main methodsRats were administered with dexamethasone (Dex) orally (1 mg/kg/day) for 6 weeks at a resting or an active period. After the end of the treatment, bone density of femur, biomarkers of bone formation and resorption, and other biomedical variables were measured.Key findingsBone density of femur was significantly decreased by the 6-week treatment with Dex, and the degree of decrease in the 14 HALO (hours after light on) dosing group (an active period) was larger than that in the 2 HALO dosing group (a resting period). Although urinary calcium excretion was accelerated by Dex treatment, secondary hyperparathyroidism was not detected. Histomorphometry analysis showed that Dex suppressed bone resorption, which was larger in the 2 HALO than in the 14 HALO groups. These data indicate that Dex equally suppressed bone formation in the 2 and 14 HALO groups, but inhibited bone resorption more in the 2 HALO than in the 14 HALO groups.SignificanceThis study shows that the decrease in bone density induced by Dex was changed by its dosing-time.     

Adaptive significance of egg size plasticity in response to temperature in the migrant skipper, Parnara guttata guttata (Lepidoptera: Hesperiidae)

Females of the migrant skipper, Parnara guttata guttata, that are reared under lower temperatures lay smaller eggs. The adaptive significance of egg size plasticity in response to temperature is unknown in this species. We suggest, based on the following experimental results, that P. g. guttata uses temperature as an indirect cue to predict the host condition (leaf toughness) of the next generation. First, larvae were reared under the typical conditions of temperature and photoperiod experienced during the immature stages in the first, second, and overwintering (third) generations (LD 16:8 at 25°C, LD 14:10 at 25°C and LD 14:10 at 20°C). Females reared under LD14:10 at 20°C produced more, smaller eggs than those reared under LD14:10 and LD16:8 at 25°C. Secondly, survival rates of first instar larvae derived from females reared under the three photoperiod/temperature treatments were measured on young soft rice leaves (soft), or tough, old rice leaves (tough). Survival rates of hatchlings reared on soft and tough leaves did not differ when females were reared under LD16:8 and LD14:10 at 25°C. However, hatchling survival was significantly higher on soft than on tough leaves when females were reared under LD14:10 at 20°C. Thirdly, we found that egg size plasticity in response to temperature in P. g. guttata may be a threshold response. Temperatures below 20°C experienced during the immature stages may be effective for production of smaller and more eggs in the overwintering generation of P. g. guttata.     

The genus Ponticulomyces (Physalacriaceae, Agaricales) from Japan

Two species of the genus Ponticulomyces collected from Japan for the first time are described and illustrated. Ponticulomyces kedrovayae is characterized by its lamellae staining yellow when bruised and in age, stipe lacking an annulus and a pseudorhiza, scattered pileal hairs, and large amygdaliform basidiospores. It mainly occurs on dead wood of Fagus crenata. Ponticulomyces orientalis is characterized by its scattered pileal hairs and broadly ellipsoid to ellipsoid basidiospores. It was collected mostly on dead wood of Cameria japonica.