• Preventive Nutrition and Food Science
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• 제1권2호
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• pp.252-255
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• 1996

As an index of freeze-injury of yeast, the leakage of intracellular substances from yeast cells after freeze-thawing was investigated. It was found that much more ultraviolet-absorbing substances leaked out from non-freeze tolerant yeast (NETY) than from freeze-tolerant yeast. Furthermore, the rate of leakage of cellular substances form NFTY during incubation exceeded that of FTY, indicating that NFTY is more susceptible to freeze-injury than FTY during frozen-storage. An apparent degradation of phospholipid was observed during incubation of perfermented frozen-cells of NFTY, while little change of phospholipid occurred in FTY, These results suggested that the difference in the sensitivity of yeast might be due to the strength of cell membrane in terms of the degradation of phospholipid by enzymes, phospholipases, attached to cell membranes.

• Journal of Microbiology and Biotechnology
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• 제21권9호
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• pp.954-959
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• 2011

There have been a number of studies conducted in order to compare the efficiencies of recovery rates, utilizing different protocols, for the isolation of L. monocytogenes. However, the severity of multiple cell injury has not been included in these studies. In the current study, L. monocytogenes ATCC 19112 was injured by exposure to extreme temperatures ($60^{\circ}C$ and $-20^{\circ}C$) for a one-step injury, and for a two-step injury the cells were transferred directly from a heat treatment to frozen state to induce a severe cell injury (up to 100% injury). The injured cells were then subjected to the US Food and Drug Administration (FDA), the ISO-11290, and the modified United States Department of Agriculture (mUSDA) protocols, and plated on TSAyeast (0.6% yeast), PALCAM agar, and CHROMAgar Listeria for 24 h or 48 h. The evaluation of the total recovery of injured cells was also calculated based on the costs involved in the preparation of media for each protocol. Results indicate that the mUSDA method is best able to aid the recovery of heat-injured, freeze-injured, and heat-freeze-injured cells and was shown to be the most cost effective for heat-freeze-injured cells.

• 식물조직배양학회지
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• 제27권4호
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• pp.339-343
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• 2000

When plants are exposed to subfreezing temperatures ice crystals are forming within extracelluar space in leaves. The growth of ice crystal is closely related to the degree of freezing injury. It was shown that an antifreeze protein binds to an ice nucleator through hydrogen bonds to prevent growth of ice crystal and also reduces freezing damage. The antifreeze proteins in plants are similar to PR proteins but only the PR proteins induced upon cold acclimation were shown to have dual functions in antifreezing as well as antifungal activities. Three of the genes encoded for CLP, GLP, and TLP were isolated from barley and Kentucky bluegrass based on amino acid sequence revealed after purification and low temperature-inducibility as shown in analysis of the protein. The deduced amino acid of the genes cloned showed a signal for secretion into extracellular space where the antifreezing activity sup-posed to work. The western analysis using the antisera raised against the antifreeze proteins showed a positive correlation between the amount of the protein and the level of freeze tolerance among different cultivars of barely. Besides it was revealed that TLP is responsible for a freeze tolerance induced by a treatment of trinexapac ethyl in Kentucky bluegrass. Analysis of an overwintering wild rice, Oryza rufipogon also showed that an acquisition of freeze tolerance relied on accumulation of the protein similar to CLP. The more direct evidence for the role of CLP in freeze tolerance was made with the analysis of the transgenic tobacco showing extracellular accumulation of CLP and enhanced freeze tolerance measured by amount of ion leakage and rate of photosynthetic electron transport upon freezing. These antifreeze proteins genes will be good candidates for transformation into crops such as lettuce and strawberry to develop into the new crops capable of freeze-storage and such as rose and grape to enhance a freeze tolerance for a safe survival during winter.

• 한국환경농학회지
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• 제33권4호
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• pp.403-408
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• 2014

난온대성 낙엽과수인 참다래는 겨울철 동해에 민감하여 주산지역에서도 월동기에 주간을 피복하고 있다. 본 연구는 참다래 재배에서 월동기 주간부 동해 예방을 위해 사용되고 있는 피복재의 온도특성에 대해 알아보고자 하였다. 실험은 경남 사천의 5-6년생 '헤이워드' 과수원에서 이루어 졌다. 사용된 피복재는 볏짚과 은박쿠션 2종류였으며, 낙엽후인 12월 하순에 설치하여 이듬해 4월 중순에 제거하였다. 피복재 내부의 온도 측정은 WatchDog 2450 (Spectrum Technologies, Inc.)을 이용하여 2013-2014년1-3월에 측정 비교하였다. 1월과 2월 최저기온이 각각 $-10.2^{\circ}C$, $-10.9^{\circ}C$로 추웠던 2013년에 은박쿠션 내부의 최저기온은 1, 2월에 각각 $-6.3^{\circ}C$, $-2.6^{\circ}C$로 보온효과가 뛰어났다. 반면, 볏짚 내부의 1, 2월 최저기온은 각각 $-9.8^{\circ}C$, $-9.9^{\circ}C$로 대기 온도와 큰 차이가 없어 보온효과가 미미했다. 측정 시각에 따른 평균기온의 변화에서도 은박쿠션이 볏짚에 비해 낮 동안의 열을 피복재 내부에 잘 간직하여 야간 온도를 상대적으로 높게 유지했다. 따라서 참다래 나무의 월동 피복 자재로써 은박쿠션이 볏짚에 비해 보다 효과적일 것으로 판단되었다.

• 한국식품조리과학회지
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• 제11권1호
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• pp.9-12
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• 1995

냉동내성빵효모의 냉동내성기구를 규명하기위한 일환으로 세포의 막 유동성에 관계되는 지질분석을 행하였다. 그 결과, 냉동내성효모 $D_{2-4}$나 CFY보다 비냉동내성 효모 Saccharomyces cerevisiae 2001이 스테롤 : 인지질의 비율이 비교적 높았다. 또 인지질조성이 조사되었는 데, 세효모 모두에 있어 phosphatidylcholine 함량이 가장 높았다. Phosphatidylcholine : phosphatidylethanolamine의 비율은 냉동내성효모가 비내성효모 보다 높게 나타났다. 인지질에 연결된 지방산 함량을 보면, linoleic acid 함량은 $D_{2-4}$에서 높게 나타났으며 지방산의 불포화도는 $D_{2-4}$가 CFY나 S. cerevisiae보다 높았다. 이 결과에서 yeast 세포막의 유동성은 각 효모마다 다르며, 이것들이 저온에서의 효모의 동결장해에 영향을 주는 것으로 생각된다. 생각된다.

• 한국농림기상학회지
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• 제11권4호
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• pp.213-220
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• 2009

복숭아 나무 '장호원황도' 품종의 결과지에 대한 월동기간 중 생리적 내한성을 가리키는 지표로서 일별 기온에 의해 계산되는 휴면심도를 설정하였다. 휴면심도 추정모형의 최적모수(기준온도, 저온요구도)를 도출하기 위해 2008-2009 겨울 동안 총 12회에 걸친 실험을 수행한 결과, 내생휴면해제에 필요한 '장호원황도'의 기준온도 $5.7^{\circ}C$와 저온요구도 -108을 얻었다. 1992-2008년 기간 중 수원기상대 일 최고 및 최저기온자료를 이용하여 이 모형에 의해 '장호원황도'의 만개기를 예측하고 기존의 DVS모형과 회귀모형에 의한 예상 만개기와 비교한 결과 이 모형의 예측능력이 우수하였다. 이 모형에 의해 추정된 휴면심도를 선행연구에서 얻은 동해유발온도와 결합하여 동해위험확률을 계산할 수 있는 경험식을 도출하였다. 날짜와 최저기온이 주어지면 이 식에 의해 '장호원황도'의 갈변이나 발아장해 등 동해증상이 나타날 수 있는 확률, 즉 동해위험 지수를 미리 알 수 있으므로 복숭아 재배농가의 동해 경감에 기여할 것으로 기대된다.

• 한국농림기상학회지
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• 제11권4호
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• pp.221-232
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• 2009

본 연구는 겨울철 휴면심도와 동해유발온도를 기반으로 작성된 복숭아 나무 '장호원황도' 품종의 휴면지에 대한 동해위험지수 계산식을 고해상도 전자기후도와 결합하여 현재평년(1971-2000년)의 기후조건에서 동해위험의 지역적 분포를 파악하였다. 이를 기준으로 두고 기후변화 시나리오에 근거한 미래 3개 평년(2011-2040년, 2041-2070년, 2071-2100년)의 기온자료에 동일한 방법을 적용하여 얻은 동해위험지수와 비교함으로써 기후변화에 따른 이들 위험지역의 이동을 경관규모에서 추적하였다. 현재평년(1971-2000년) 기후조건에서는 전 국토의 4%가 안전지대, 88%가 동해 위험 경계지대, 8%가 위험지대로 탐색되었다. 시나리오 기후조건에서는 가까운 미래(2011-2040년)와 먼 미래(2041-2100년)에 모두 경계지대가 줄어드는 반면 안전지대와 위험지대가 다같이 증가하였다. 이 방법은 경기도 이천, 경북 청도 등 복숭아 주산지 내의 위험지대를 경관규모에서 탐색하는 데도 이용될 수 있음이 확인되었으므로 앞으로 농업분야 기후변화 영향평가 및 취약성 분석에 기여할 것으로 기대된다.

• 한국식품위생안전성학회지
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• 제3권1호
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• pp.19-26
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• 1988

Most of meat spoilage bacteria area Gram negative, which are very sensitive to freezing ; for instance , 90% of E. coli cells are killed or sub-lethally injured by freezing at -3$0^{\circ}C$, and the freeze-injury rate is dependent upon freezing rate. Since the injured bacterial cells are sensitive to selective agents, they fail to multiply in selective media. Injured bacterial cells are, however, capable of spontaneous repair at appropriate environmental and nutritional conditions . Enumeration of injured bacterial cells involves artificial induction of repair at these conditions. Cubic beef samples(3$\times$3$\times$3cm) were frozen at -6$0^{\circ}C$, -4$0^{\circ}C$, or -18$^{\circ}C$. The samples frozen at each temperature were thawed at 4$^{\circ}C$, 2$0^{\circ}C$, or by microwave . After these respective freezing an thawing treatments, the percentage of sub-lethally injured total coliforms out of total surviving ones was measured and compared. The results were as follows: 1. The interaction between freezing and thawing on injury rate was not significant. 2. The injury rates(as means of all three thawing treatments post-freezing) by freezing at -6$0^{\circ}C$, -4$0^{\circ}C$, or -18$^{\circ}C$ were 32.2$^{\circ}C$ and 19.2$^{\circ}C$ respectively . 3. The injury rates(as means of all three freezing treatments)by thawing at 4$^{\circ}C$, 2$0^{\circ}C$, or by microwave were 49.3%, 11.7% and 21.0% respectively. The highest injury rate was caused by freezing at -6$0^{\circ}C$ and subsequent thawing at 4$^{\circ}C$. However since the injury rates by freezing treatment were not significantly different, freezing at -18$^{\circ}C$ and subsequent thawing at 4$^{\circ}C$ can also be recommended , from an economic perspective.

• Archives of Pharmacal Research
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• 제27권11호
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• pp.1136-1140
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• 2004

Red ginseng and fermented red ginseng were prepared, and their composition of ginsenosides and antiischemic effect were investigated. When ginseng was steamed at 98-$100{\circ}C$ for 4h and dried for 5h at $60{\circ}C$, and extracted with alcohol, its main components were ginsenoside $Rg_3$ > ginsenoside $Rg_1$> ginsenoside $Rg_2$. When the ginseng was suspended in water and fermented for 5 days by previously cultured Bifidobacterium H-1 and freeze-dried (fermented red ginseng), its main components were compound K > ginsenoside $Rg_3{\geq}$ ginsenoside $Rg_2$. Orally administered red ginseng extract did not protect ischemia-reperfusion brain injury. However, fermented red ginseng significantly protected ischemica-reperfusion brain injury. These results suggest that ginsenoside Rh2 and compound K, which was found to be at a higher content in fermented red ginseng than red ginseng, may improve ischemic brain injury.

• International Journal of Industrial Entomology and Biomaterials
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• 제35권2호
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• pp.123-128
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• 2017

Hangover due to alcohol consumption causes social and physical problems. There is a growing interest in edible insects worldwide. We have previously published a new technology to make hard mature silkworm, Bombyx mori, into edible form, steamed and freeze-dried mature silkworm larval powder (SMSP). In this study, AIN-76 or SMSP (0.1 and 1 g/kg rat body weight) containing diets in SD rats were pretreated for 2 weeks, and ethanol (3 g/kg rat body weight) was administered as an oral gavage and sacrificed after 3 hours. As a result, blood alcohol and aldehyde levels were significantly decreased in SMSP fed rats. In addition, liver injury markers, alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were significantly decreased in SMSP group compared to ethanol group. $TNF-{\alpha}$, an inflammatory cytokine, and malondialdehyde (MDA), an oxidative stress marker, also showed a dose-dependent decrease in the group receiving SMSP. Conclusively, consumption of SMSP not only reduced hangover induced by ethanol, but also decreased liver damage, oxidative stress, and inflammatory response.