• Asian-Australasian Journal of Animal Sciences
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• 제14권2호
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• pp.163-169
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• 2001

Despite the high potency of the retrovirus vector system in gene transfer, one of the main drawbacks of has been difficulty in preparing highly concentrated virus stock. Numerous efforts to boost the virus titer have ended in unsatisfactory results mainly due to fragile property of retrovirus envelope protein. In this study, to overcome this problem, we constructed our own retrovirus vector system producing vector viruses encapsulated with VSV-G (vesicular stomatitis virus G glycoprotein). Concentration process of the virus stock by ultracentrifuge did not sacrifice the virus infectivity, resulting in more than 108 to 109 CFU (colony forming unit) per ml on most of the target cell lines tested. Application of this high-titer retrovirus vector system was tested on chicken embryos. Injection of virus stock beneath the blastoderms of pre-incubated fertilized eggs resulted in chick embryos expressing E. coli LacZ gene with 100% efficiency. Therefore, our results suggest that it is possible to transfer the foreign gene into chicken embryo using our high-titer retrovirus vector.

• 한국수산과학회지
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• 제51권2호
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• pp.121-126
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• 2018

The purpose of this study was to assess bacteriological hazards in the following 7 kinds of minimally processed shellfish products purchased from Korean seafood retail outlets: raw oysters stored with seawater in polyethylene bags, frozen oysters, raw mussels, frozen mussels, boiled mussels, raw short-necked clam, and frozen short-necked clams, obtained from Korean seafood retail outlets. The total coliform and Escherichia coli counts determined in all samples were detected below regulation limit of the Korean government guidelines (Food Code). In addition, the high-risk bacterial pathogens, Listeria monocytogenes, Salmonella spp., and E. coli O157:H7 were not detected in any samples. Low-risk pathogens such as Staphylococcus aureus and Vibrio parahaemolyticus were detected at levels above $1.0{\times}10^2$ colony forming unit (CFU)/g in some minimally processed shellfish products. Notably, S. aureus was detected in all samples. Raw oysters stored with seawater in polyethylene bags, frozen oysters, and boiled blue mussels are commonly ingested without heating, and therefore these minimally processed shellfish products pose bacteriological hazards. The detection of S. aureus in all shellfish products, an organism indicative of poor personal hygiene, which can grow and multiply during distribution, indicates the necessity of improving the food safety of minimally processed shellfish products.

• 한국축산시설환경학회지
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• 제7권3호
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• pp.191-195
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• 2001

양돈.양계농장에서 가축음용수 수질향상을 위하여 이용이 확대되고 있는 오존발생기의 이용효과를 구명하고자 가축음용수에 3종의 표준균주를 접종 후 $O_3$A, $O_3$, UVL 등 3종류의 오존발생기를 공시하여 처리하였으며 그 결과는 다음과 같다. 1.가축음용수 오존처리시 pH는 $O_3$A구 6.84에서 8.01로, $O_3$구 6.81에서 7.59로 증가 했으나 UVL, Control구는 변화가 없었다. 2. 용존산소량은 $O_3$A구 6.43ppm에서 8.43 ppm으로, $O_3$구 6.40ppm에서 8.40ppm 으로 증가 했으나 UVL, Control구는 변화가 없었다. 3. 산화환원전위차는 $O_3$A구는 처리전 168.7 mV에서 502.3mV로 증가하였으며 $O_3$구는 164.3mV에서 409.7mV로 급격히 증가하였으나 UVL구나 Control구는 완만찬 증가를 보였다. 4. 가축음용수에 E. coli 08:$H^-$, Salmonella typhimurium, Staphylococcus aureus를 접종 후 오존처리시 처리 30분 후 세균수는 급격하게 감소하였다.

• Journal of Microbiology
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• 제35권1호
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• pp.1-9
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• 1997

Distribution of airborne microorganisms was determined with two different types of air samplers, the Anderson cascade sampler and the Aerobioscope sampler, in the vicinity of Taejon. The size distribution of particles carrying bacteria and fungi was concurrently measured. The concentration of detected viable airborne particles was greatly varied. It was observed that the number of microbial particles increased in April and October. The most isze o particles carrying bacteria was larger than 4.7 .mu.m in mean aerodiameter, which made up 69.8% of the total particle fraction. About 63.2% of fungi-carrying particles were smaller than 4.7 .mu.m in aerodiameter. The distribution of particles on Yellow Sand Phenomena days was also analyzed. The number of fine particles having mass median aero-diameter from 1.0 to 10.mu.m increased on Yellow Sand Phenomena days to about 6 times that on normal days and the n umber of colony forming unit (CFU/$\textrm{m}^3$) of airborne bacteria also increased by 4.3 times in April. The reuslts from the Anderson sampler showed that the concentration of bacteria increased greatly on the fraction of fine particles ranging from 0.6 $\mu$m to 4.7 $\mu$m in diameter. Unlike the increase in bacterial floraon Yellow Sand Phenomena days, the fungal concentration slightly decreased and showed a normal size distribution parttern. This study suggests that a long-range transmission of bacteria results form bacteria adsorbing onto the fine particles during the Yellow Sand Phenomena.

• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.234-243
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• 2007

Vibrio vulnificus is an opportunistic pathogen that causes septicemia in humans. To identify the genes associated with its pathogenicity, in vivo expression technology (IVET) was used to select genes specifically expressed in a host, yet not significantly in vitro. Random lacZ-fusions in the genome of V vulnificus strain MO6-24/O were constructed using an IVET vector, pSG3, which is a suicide vector containing promoterless-aph and -lacZ as reporter genes. A total of ${\sim}18,000$ resulting library clones were then intraperitoneally injected into BALB/c mice using a colony forming unit (CFU) of $1.6{\times}10^6$. Two hours after infection, kanamycin was administered at $200{mu}g$ per gram of mouse weight. After two selection cycles, 11 genes were eventually isolated, which were expressed only in the host. Among these genes, VV20781 and VV21007 exhibiting a homology to a hemagglutinin gene and tolC, respectively, were selected based on having the highest frequency. When compared to wild-type cells, mutants with lesions in these genes showed no difference in the rate of growth rate, yet a significant decrease in cytotoxicity and the capability to form a biofilm.

• The Plant Pathology Journal
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• 제32권5호
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• pp.469-480
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• 2016

Bacterial wilt and grey mould in tomato plants are economically destructive bacterial and fungal diseases caused by Ralstonia solanacearum and Botrytis cinerea, respectively. Various approaches including chemical and biological controls have been attempted to arrest the tomato diseases so far. In this study, in vitro growths of bacterial R. solanacearum and fungal B. cinerea were evaluated using four different vitamins including thiamine (vitamin B1), niacin (vitamin B3), pyridoxine (vitamin B6), and menadione (vitamin K3). In planta efficacies of the four vitamin treatments on tomato protection against both diseases were also demonstrated. All four vitamins showed different in vitro antibacterial activities against R. solanacearum in dose-dependent manners. However, treatment with 2 mM thiamine was only effective in reducing bacterial wilt of detached tomato leaves without phytotoxicity under lower disease pressure ($10^6$ colony-forming unit [cfu]/ml). Treatment with the vitamins also differentially reduced in vitro conidial germination and mycelial growth of B. cinerea . The four vitamins slightly reduced the conidial germination, and thiamine, pyridoxine and menadione inhibited the mycelial growth of B. cinerea. Menadione began to drastically suppress the conidial germination and mycelial growth by 5 and 0.5 mM, respectively. Grey mould symptoms on the inoculated tomato leaves were significantly reduced by pyridoxine and menadione pretreatments one day prior to the fungal challenge inoculation. These findings suggest that disease-specific vitamin treatment will be integrated for eco-friendly management of tomato bacterial wilt and grey mould.

• 한국식생활문화학회지
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• 제36권5호
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• pp.512-521
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• 2021

This study investigated the quality characteristics of sweet pumpkin after blanching. Sweet pumpkins were blanched in distilled water, 2% citric acid and 2% NaCl water at 100℃ for 3 min. The cooking loss of sweet pumpkin in the blanching groups was lower than that in the control group, and greenness and yellowness in the blanching groups were higher than those in the control group (p<0.001). Total polyphenol content (TPC) of sweet pumpkin increased after blanching (p<0.05), and TPC true retention (TR) was measured with the highest NB. CON and NB were significantly higher in ?-carotene content (p<0.001). Lutein content in the blanching treatment groups was lower than that in the control group, but NB was the highest between the blanching groups (p<0.001). DPPH and ABTS⁺ radical scavenging activity assays revealed higher antioxidant activity in the NB groups among the blanching groups (p<0.001). The CON was 2.44 log colony-forming unit (CFU)/ g in the total bacterial count, but there were no microorganisms in the blanching groups. In conclusion, blanching with the addition of 2% NaCl can inhibit the growth of microorganisms and improve TR and antioxidant activities in sweet pumpkin.

• 한국식생활문화학회지
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• 제39권2호
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• pp.119-126
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• 2024

This study was conducted to examine the microbiological quality indicators (total bacterial count and coliform count) and physicochemical quality indicators (pH, redness, volatile basic nitrogen [VBN] content) of meat according to various storage temperatures (-20~15℃) and packaging methods (wrap, vacuum). Based on these results, we proposed a safe consumption period. Redness, pH, and VBN content were not considered appropriate for setting the expiration date, as the redness and pH of the meat after spoilage were better than the standard values for both vacuum and wrap packaging (p<0.05). Additionally, the VBN content at 2 and 4℃ increased slightly (fresh level) until the initial time of spoilage (1.0×10⁶ colony-forming unit [CFU]/cm²) and then increased rapidly thereafter. Therefore, the results were not consistent with microbial spoilage. When the decay point was evaluated based on the presence of microorganisms, vacuum packaging extended the storage period approximately 2.5-fold when compared with wrap packaging, and the meat could be stored at 2 or 4℃ for 40 or 23 days, respectively. Therefore, to evaluate meat quality, microbial indicators should be considered first. The microbiological standards proposed in this study can be used for safety management during the distribution of meat. However, to ensure meat safety, additional investigations of appropriate indicators of freshness must be conducted.

• 농업과학연구
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• 제22권2호
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• pp.188-196
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• 1995

장류제조에 유용성이 높은 곰팡이를 분리할 목적으로 재래식 메주를 수집하여 aflatoxin 생성 유무를 확인하고 재래식 메주의 미생물 분포와 효소 역가를 측정한 후 효소역가가 높은 균주로 Aspergillus oryzae O4-5를 분리 선정한 결과를 요약하면 다음과 같다. 1. 1994년 12월에서 1995년 2월 사이에 전국 각 지역에서 수집한 메주 중의 mycotoxin 생성을 검출하기 위하여 EZ-Screen Test Kit와 HPLC에 의해 분석한 결과 aflatoxin은 검출되지 않았다. 2. 메주 중의 곰팡이 수는 $1.3{\times}10^4-2.8{\times}10^6CFU/g$ 이었으며 효모수는 $1{\times}10^2-1.5{\times}10^6CFU/g$으로 시료별 차이가 대단히 컸다. 또한 호기성 세균수는 $2.0{\times}10^7-8.0{\times}10^7CFU/g$, 혐기성 세균은 $3.0{\times}10^6-7.3{\times}10^8CFU/g$ 이었다. 3. 메주 19 중의 ${\alpha}$-amylase는 5 - 80 units, gluco-amylase는 2 - 34 units로 지역별 메주 간의 차이가 심하였다. 4. 메주 1g 중의 산성 protease, 중성 protease 및 알칼리성 protease 역가는 5 - 33 units, 5 - 302 units 및 5- 363 units였으며 시중제품인 D회사의 개량메주는 산성 protease가 66 unitts로 재래식 메주 보다 높았다. 5. 재래식 메주로 부터 amylase와 protease가 높아 유용성이 높은 CNU O4-5는 Aspergillus oryzae로 동정되었다. 6. 우수 균주인 CNU O4-5균주의 산성 및 중성 protease는 장류공업에서 실제 이용하고 있는 Aspergillus oryzae JM 보다 10%정도 높게 나타났으며 amlylase 역가는 비슷 하였다.

• 한국균학회지
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• 제27권2호통권89호
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• pp.132-137
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• 1999

본 연구는 느타리버섯 갈반병 병원균인 pseudomonas tolaasii의 진단을 위한 분자 marker를 개발하기 위해 수행되었다. 세균의 반복염기서열과 펙틴 분해효소 유전자로부터 제작된 여러개의 primer들을 이용해 식용버섯으로부터 분리된 Pseudomonas종들로부터 DNA 다형성을 유도한 바펙틴 분해 효소로부터 제작된 PEU1 primer는 다른 Pseudomonas종들로부터 P. tolaasii를 구분시키는 다형성 밴드를 생성하였다. P. tolaasii 6균주에 공통적으로 나타나는 1.0kb와 0.4kb의 두 가지 밴드를 pGEM-T에 클로닝하고 이들을 각기 pPTOP1과 pPTOP2로 명명하고 probe로 이용하였다. 0.4kb 크기의 pPTOP2의 삽입 DNA는 P. tolaasii 6균주와 hybridization이 이루어진 반면 다른 Pseudomonas종과는 반응하지 않았다. 0.4kb크기의 pPTOP2의 삽입 DNA를 probe로 이용해 dot blot hybridization한 결과 P. tolaasii는 $1.5{\times}10^3\;cfu$까지 검출이 가능함을 확인하였다.