• Applied Microscopy
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• v.29 no.2
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• pp.241-253
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• 1999

Fertilization pattern of north temperate bats is known to be unique for their sperm storage in the female reproductive tract during hibernation (e.g. Korean greater horseshoe bats). They copulate in fall but their ejaculated spermatozoa survive until the next spring. In another words they can persist to survive during long hibernation under the cold condition $(8\sim13^{\circ}C)$ and are to be fertilized with the ovum ovulated in the next spring, so called delayed fertilization. The present study was designed to observe morphological and functional changes of spermatozoa plasma membrane of the bats, hamsters which are hibernators, and mice which are non-hibernators in the room and the cold (bat-hibernation) temperatures and to confirm influence of the temperature on spermatozoa; survival rate, acrosome reaction rate, protein distribution, $Na^+-K^+-ATPase$ activities and scanning electron microscopic histochemistry. Based on the experimental results obtained in the present study, there were no significant morphological and functional differences in the spermatozoa plasma membrane in both the room and cold (bat-hibernation) temperatures and such an absence of difference suggests that the spermatozoa plasma membrane might play a pertinent role as a protector for consistent fertilization during and after hibernation.

• International Journal of Industrial Entomology and Biomaterials
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• v.26 no.2
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• pp.124-130
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• 2013

Bumblebees are widely used to pollinate various greenhouse crops. Among the different bumblebee species, Bombus ignitus is indigenous to Korea, China, Japan and Russia. B. ignitus undergoes one generation per year, and artificial hibernation is essential for year-round rearing of the bumblebee. Keeping the queens under low-temperature conditions for several months is an effective method for terminating their diapause and promoting colony development. In the present study, we investigated how cold temperature affects the artificial hibernation of B. ignitus queens. Under chilling temperatures of $-2.5^{\circ}C$, $0^{\circ}C$, $2.5^{\circ}C$ and $5^{\circ}C$ with constant humidity >80%, the queens stored at $2.5^{\circ}C$ exhibited the highest survival rates, which were 74.0% at one month, 67.0% at two months, 60.0% at three months, 46.0% at 4 months, 33.0% at 5 months and 24.0% at 6 months. Lower survival rates were observed at $0^{\circ}C$, $5^{\circ}C$, $7.5^{\circ}C$ and $12.5^{\circ}C$. At $2.5^{\circ}C$ the colony developmental characteristics after diapause were 1.2- to 1.5-fold greater than those when queens were stored at $5^{\circ}C$. Thus, $2.5^{\circ}C$ and 70% R.H. were the most favorable chilling temperature and humidity conditions for terminating the diapause of B. ignitus queens.

• Korean Journal of Veterinary Research
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• v.36 no.1
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• pp.11-21
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• 1996

Comparing hibernation with active periods, the regional distribution and relative frequencies of gastrointestinal endocrine cells were studied immunohist-ochemically in the GITs of the Rana dybowskii. Six kinds of endocrine cells were identified in this study. In this study, several novel findings were emerged: in hibernation period, the perdominant presence of immunoreactive cells; the widely distributional regions of glucagon-, Gas/CCK- and BPP-immunoreactive cells; the intense reaction of immunostaining against the antiserum; and the existence of 5-HT- and somatostat-in-immunoreactive cells in upper regions of the fundic glands. These results suggest that the gastro-entero-endocrine cells in hibernation period synthesize continuously its gut hormones and accumulate in their cytoplasms.

• Animal cells and systems
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• v.1 no.1
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• pp.99-105
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• 1997

Using three species of Korean frogs (Rana dybowskii, R. rugosa and R. nigromaculata), the annual spermatogenic pattern, the seasonal changes in the steroidogenic competence, and responsiveness of testis to gonadotropins in terms of testosterone secretion in vitro were examined. The spermatogenic pattern of R. dybowskii was classified as a discontinuous type since spermatogenesis stops completely after spawning in late winter (February) until mid-summer (July). In contrast, the pattern of R. nigromaculata and R. rugosa was classified as a potent continuous type since sperm was always present in the seminiferous tubules all year round. In all three species, the levels of testicular testosterone and that of testosterone secreted by testis following in vitro culture were very low in late summer (August), but increased thereafter until winter (hibernation period). Interestingly, responsiveness of testis in vitro to gonadotropins in terms of testosterone secretion increased markedly in November (early hibernation period). Specifically, bullfrog LH was more effective than FSH in stimulating the secretion of testosterone by frog testis in vitro during hibernation period. This fact suggests that testosterone secretion by testis during hibernation is at least regulated by the pituitary gonadotropin rather than environmental factors. Taken together, the data presented here suggest that testicular cycles of three species of Korean frogs are closely linked to their females breeding cycles, and are eventually controlled by various environmental cues.

• 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.

• The Korean Journal of Zoology
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• v.17 no.2
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• pp.69-80
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• 1974

The mucosubstances in the gastrointestinal mucous secreting cells of Rana rugosa were detected histochmeically during pre-hibernating, hibernating, post-hibernating and active phases. The results of the observation were as follows: 1. The mucosubstances in the gastrointestinal mucous secreting cells of active frog were strongly PAS-active in stomach, PAS-active and alcianophilic at pH 2.5 in small intestine and alcianophilic at pH 2.5 in large intestine. 2. The PAS-active mucosubstances in the gastric surface epithelial cells were increased remarkably during hibernation. 3. The alcianophilic mucosubstances at both pH 2.5 and pH 1.0 were decreased remarkably in the goblet cells of small intestine during hibernation, but a little PAS-active ones were increased. 4. The alcianophilic mucosubstances at pH 2.5 were decreased remarkably and a lttle PAS-active ones also were done in the goblet cells of large intestine during hibernation. 5. The increases of the contained quantity of mucosubstances in the gastric surface epithelial cells during hibernationi may have theeffects of preventing cohesions of gastric mucosae and suppressing activities of gastric acid and enzymes. The mucosubstances neutral acidity in the intestine during hibernation may be secreted, because of acidity being done near neutrality in its lumen, due to remarkable decrease of intestinal juices and gastric acids.

• Journal of Ecology and Environment
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• v.32 no.3
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• pp.191-195
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• 2009

We monitored 38 hibernation sites of Myotis formosus in South Korea and recorded the number of bats occupying each site and assessed the micro-climate at the sites during four winters from 2005 to 2009 at. The mean rock temperature of the bat roosting sites was $13.2{\pm}1.4^{\circ}C$ and the mean body temperature of the hibernating bats was $13.3{\pm}1.3^{\circ}C$. The number of hibernating bats was negatively related to the size of the entrance and positively related to the minimum ambient temperature and humidity in the site interior. More bats hibernated in roosts with smaller entrances and higher minimum ambient temperatures, and more bats selected sites presenting a narrow temperature range. This study showed that the internal environments of hibernacula of M. formosus were highly stable despite dramatic variation in the external environment.

• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.1
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• pp.107-109
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• 2004

The present investigation reports a phenomenon hitherto unknown in tropical sericulture, wherein dia-pause nature of bivoltine eggs is overcome through a cross with a non-diapausing race of silkworm, Bombyx mori, L. Eggs of bivoltine silkworm Bombyx mori, L. generally do not hatch under tropical conditions. To prevent diapause, they are subjected to acid treatment or low temperature hibernation scheduled. A race developed at KSSRDI is found to prevent the diapause nature of bivoltine eggs when crossed as male parent, without any acid treatment or hibernation schedule. This phenomenon is reported for the first time, being unique, opens up interesting area of research in silkworm genetics of commercial implications in the industry.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2001.05a
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• pp.57-57
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• 2001

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.12
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• pp.618-629
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• 2007

In this paper, we propose an effective memory test environment, called a virtualized kernel, for 64bit multi-core computing environments. The term of effectiveness means that we can test all of the physical memory space, even the memory space occupied by the kernel itself, without rebooting. To obtain this capability, our virtualized kernel provides four mechanisms. The first is direct accessing to physical memory both in kernel and user mode, which allows applying various test patterns to any place of physical memory. The second is making kernel virtualized so that we can run two or more kernel image at the different location of physical memory. The third is isolating memory space used by different instances of virtualized kernel. The final is kernel hibernation, which enables the context switch between kernels. We have implemented the proposed virtualized kernel by modifying the latest Linux kernel 2.6.18 running on Intel Xeon system that has two 64bit dual-core CPUs with hyper-threading technology and 2GB main memory. Experimental results have shown that the two instances of virtualized kernel run at the different location of physical memory and the kernel hibernation works well as we have designed. As the results, the every place of physical memory can be tested without rebooting.