• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.289-292
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• 2001

The present study revealed that polyphenol induces the hibernation of mammalian cells at the living body temperature. It was found that polyphenol is a cytostatic sleeping agent for mam-malian cells, where almost all cells resume proliferation after the hibernation period and cell death seldom occurs. By changing the concentration for polyphenol, various mammalian cells can be stored under different conditions, such as temporary sleep, and hibernation condi-tions.

• Animal cells and systems
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• v.13 no.2
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• pp.119-125
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• 2009

Mammalian hibernation is a type of natural adaptation that allows organisms to avoid harsh environment and to increase the possibility of survival. To investigate the molecular link between circadian and hibernating rhythms in the greater tube-nosed bats, Murina leucogaster, we set out to identify circadian genes that are expressed in bats, with specific focus on the PAS domain by using PCR-based screens. We could isolate a eDNA clone, designated as LPAS1, that encodes a protein of 521 amino acid residues. LPAS1 is closely related with CLOCK family with the highest homology to human CLOCK. Based on RT-PCR analyses, LPAS1 transcripts are ubiquitously present in tissues from both summer active and winter dormant periods. Given that LPAS1 is a member of the bHLH-PAS protein superfamily but lacks polyglutamine transactivation domains, it is likely to function as a repressor for endogenous CLOCK to hinder its roles in promoting transcription. Our result will open a new avenue to further examine the functional interconnection between the circadian clock and the circannual clock such as mammalian hibernation.

• Applied Microscopy
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• v.21 no.2
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• pp.14-28
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• 1991

The present study was designed in order to clarify ultrastructural characteristies of the spermatogenetic process and to examine survival state of the spermatozoa introduced into the female reproductive tract after autumnal coitus in the Korean greater horseshoe bats(Rhinolophus ferrumeguinum korai). The general morphological characteristics of spermatogenesis were principally similar to those of the other mammalian species; acrosomal formation, flagellar formation, middle piece formation and concentration of the spermatozoan nucleus. The spermatozoa introduced into the vagina were found to be dead forming a vaginal plug, the opaque central core of which consisted of trapped dead spermatozoa. Some spermatozoa introduced into the uterus were observed to be phagocytized by the polymorphonuclear leucocytes infiltrated into the uterine glandular lumen. The oviductal epithelium, consisted of ciliated and secretory cells; the luminal surface of secretory cells were covered by a number of microvilli with well developed glycocalyx, suggesting a close relationship to nutrient (e.g. glycogen) supply for the spermatozoa during hibernation.