Although hibernating mammals wake occasionally to eat during torpor, this period represents a state of fasting. Fasting is known to alter the gut microbiota in nonhibernating mammals; therefore, hibernation may also affect the gut microbiota. However, there are few reports of gut microbiota in hibernating mammals. The present study aimed to compare the gut microbiota in hibernating torpid Syrian hamsters with that in active counterparts by using culture-independent analyses. Hamsters were allocated to either torpid, fed active, or fasted active groups. Hibernation was successfully induced by maintaining darkness at 4°C. Flow cytometry analysis of cecal bacteria showed that 96-h fasting reduced the total gut bacteria. This period of fasting also reduced the concentrations of short chain fatty acids in the cecal contents. In contrast, total bacterial numbers and concentrations of short chain fatty acids were unaffected by hibernation. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments indicated that fasting and hibernation modulated the cecal microbiota. Analysis of 16S rRNA clone library and species-specific real-time quantitative PCR showed that the class Clostridia predominated in both active and torpid hamsters and that populations of Akkermansia muciniphila, a mucin degrader, were increased by fasting but not by hibernation. From these results, we conclude that the gut microbiota responds differently to fasting and hibernation in Syrian hamsters.

Aneuploidy in fetal chromosomes is one of the causes of pregnancy loss and of congenital birth defects. It is known that the frequency of oocyte aneuploidy increases with the human maternal age. Recent data have highlighted the contribution of cohesin complexes in the correct segregation of meiotic chromosomes. In mammalian oocytes, cohesion is established during the fetal stages and meiosis-specific cohesin subunits are not replenished after birth, raising the possibility that the long meiotic arrest of oocytes facilitates a deterioration of cohesion that leads to age-related increases in aneuploidy. We here examined the cohesin levels in dictyate oocytes from different age groups of humans and mice by immunofluorescence analyses of ovarian sections. The meiosis-specific cohesin subunits, REC8 and SMC1B, were found to be decreased in women aged 40 and over compared with those aged around 20 years (P<0.01). Age-related decreases in meiotic cohesins were also evident in mice. Interestingly, SMC1A, the mitotic counterpart of SMC1B, was substantially detectable in human oocytes, but little expressed in mice. Further, the amount of mitotic cohesins of mice slightly increased with age. These results suggest that, mitotic and meiotic cohesins may operate in a coordinated way to maintain cohesions over a sustained period in humans and that age-related decreases in meiotic cohesin subunits impair sister chromatid cohesion leading to increased segregation errors.

Strategies to manipulate the gut microbiota in infancy have been considered to prevent the development of allergic diseases later in life. We aimed to elucidate the effects of maternal dietary supplementation with a prebiotic oligosaccharide on gut microbiota and spontaneously developing atopic dermatitis-like skin lesions in the offspring of NC/Nga mice. Female NC/Nga mice were fed diets either with or without fructooligosaccharide supplementation during pregnancy and lactation. After weaning, offspring were fed the diets supplemented with or without fructo-oligosaccharide for 11 weeks in an air-uncontrolled conventional room. Changes in gut microbiota were assessed by denaturing gradient gel electrophoresis of the PCR-amplified 16S rRNA gene. Skin lesions were evaluated by a clinical score and scratching behaviour. Serum antibody levels were measured by ELISA, and expression levels of cytokines and chemokines in lesional tissue were evaluated by quantitative RT-PCR. Maternal supplementation with fructo-oligosaccharide modulated the gut microbiota in sucklings. Although maternal supplementation with fructo-oligosaccharide suppressed the increase in clinical skin severity score and scratching behaviour in offspring, dietary fructooligosaccharide after weaning was less effective. The diminution of skin lesions was accompanied by lower serum concentrations of total IgG1 and lower expression levels of TNF-a in the lesional tissue. These data suggest that maternal consumption of fructo-oligosaccharide diminishes the severity of atopic dermatitis-like skin lesions in the offspring of NC/Nga mice. Fructo-oligosaccharide: Prebiotics: Atopic dermatitis: Gut microbiota: NC/Nga miceThe gut microbiota play an important role in maintaining host health by preventing the colonisation of pathogens, degrading dietary compounds and maintaining normal mucosal immunity. Particularly, the composition of the gut microbiota early in life profoundly influences later immune responses (1 -4) . Therefore, strategies to manipulate the microbiota in infancy have been considered in preventing the onset of allergic diseases. This idea is supported by epidemiological data demonstrating that differences in the composition of gut microbiota in infancy precede the development of atopic dermatitis (AD) (5 -8) . In addition, clinical trials showed that maternal administration of Lactobacillus rhamnosus GG (i.e. probiotics) during pregnancy and lactation was beneficial in preventing the development of AD in at-risk children during the first 4 years of life (9,10) . However, L. rhamnosus GG administration did not benefit adolescents suffering from birch pollen allergy (11) . These findings suggest that the time point for exposure to probiotics is important in preventing the development of allergic diseases.Indigestible oligosaccharides are regarded as prebiotics that affect the host by selectively stimulating the growth and/or activity of beneficial bacteria such as bifidobacteria and lactobacilli in the intestinal tract, and thus improving host...

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