• Korean Journal of Food Science and Technology
• /
• v.50 no.6
• /
• pp.594-600
• /
• 2018

Shiga toxin-producing Escherichia coli (STEC) is an important pathogenic bacterium. To control STEC, the characteristics of the ECP33 and NOECP91 coliphages, which belong to the Myoviridae family, were analyzed. The host inhibition range for a total of 44 STEC strains was 45.5% for ECP33 and 65.9% for NOECP91. ECP33 and NOECP91 were relatively stable at $65^{\circ}C$, 50 ppm of sodium hyperchlorite, and a pH value of 4-10. However, the two phages were susceptible to a temperature of $70^{\circ}C$. NOECP91 was killed within 1 h after exposure to 30% ethanol, but ECP33 showed high tolerance even after exposure to 70% ethanol for 1 h. Interestingly, the inhibition of STEC growth according to the multiplicity of infection of 0.1 was confirmed until no growth was observed after 10 hours of culture with the phages. Therefore, the ECP33 and NOECP91 phages may be applied as a biological control agent for Shiga toxin-producing E. coli.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2002.02a
• /
• pp.335-342
• /
• 2002

건고추 꼭지 제거 장치를 설계·제작하고 실험을 통하여 성능을 검증하였다. 원료 함수율 22%(wb)의 경우 꼭지 제거율은 60∼78%, 파지 발생율은 약 4% 정도로 나타났으며, 함수율 19%(wb)의 경우는 꼭지 제거율 90∼97%, 파지 발생율 약 7% 정도를 나타났다. 원료 투입량에 따른 실험 결과 꼭지 제거율 및 파지 발생율 변화가 나타나지 않아 개발된 장치의 안정성을 확인할 수 있었다.

• Korean Journal of Food Science and Technology
• /
• v.43 no.2
• /
• pp.176-181
• /
• 2011

Cronobacter sakazakii and Salmonella enterica Typhimurium are hazardous pathogens, especially for ready-toeat foods. For control of pathogens, the virulent bacteriophages were isolated, identified, and applied to infant formula milk and vegetable juice. The phages were isolated from swine feces and identified by morphology and molecular characteristics. ES2 phage for C. sakazakii and ST2 phage for S enterica Typhimurium were identified as Myoviridae and Siphoviridae, respectively. Their burst sizes were $52{\pm}5PFU/cell$ for ES2 phage and $21{\pm}3PFU/cell$ for ST2 phage after latent period of 30-40 minutes. ST2 phage showed higher heat stability at $60^{\circ}C$ than ES2 phage. ES2 phage held the growth of C. sakazakii untill 6 hr afterwhich the number decreased when applied to the infant formula milk and vegetable juice. ST2 phage also showed growth inhibition so that the number of S. enterica Typhimurium decreased. Therefore, virulent bacteriophages might be an agent for the growth inhibition of C. sakazakii and S. enterica Typhimurium in such the ready-to-eat foods.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2001.11a
• /
• pp.67-68
• /
• 2001

제지공장은 에너지 다소비 업종이며 고도의 장치산업이기 때문에 초지 설비의 효과적 운영을 통한 생산성 극대화가 경제성과 직결되어 었다. 또한 24시간 연속생산을 하는 초지 설비로 소비자가 선호하는 품질의 종이를 생산하기 위해서는 공정의 안정성 이 매우 중요하다. 이는 공정의 불안정화는 생산제품의 품질 변화를 유발함으로써 균일 성을 저하시키는 악영향을 미치기 때문이다. 제지 공정의 안정화를 저해하는 인자에는 지절, 지종 변화, 조업중단, 조업재개 둥과 공정의 특성상 수반되는 돌발사태 등이 있을 수 있다. 이들 인자 가운데 가장 심각하게 공정의 안정성을 악화시키는 것은 지절의 발 생이라 할 수 있다. 지절이 발생되면 생산성 저하 등의 여러 문제점이 발생하기도 하지 만 다량의 파지가 발생되기 때문에 공정 안정성 면에서 볼 때에도 부득이하게 생성된 다량의 파지를 공정에 재투입하기 위해 재해리해야하므로 많은 양의 백수가 소모되며 이에 따라 예기치 않은 공정 백수의 사용으로 전체 백수계에 갑작스런 변동이 생기게 된다. 백수가 파지의 해리에 사용됨에 따라 공정 내에는 추가적인 청수가 공급되어야 하므로 전체적으로는 청수의 사용량도 늘어난다. 또한 증가된 파지의 재사용도 대부분 의 공장에서 broke chest의 용량이 한정되어 있으므로 이의 적절한 컨트롤은 중요하다. 더욱이 점차 공정이 고폐쇄화됨에 따라 공정 컨트롤에 대한 여유가 적으므로 백수와 공정의 관리는 점차 어려워지고 있다. 공정 시율레이션은 현존하는 공정을 수학적으로 모델화하여 이를 컴퓨터 하드 왜어를 이용해 실제 공장에서 일어나는 상황을 모사하는 것이다. 이러한 공정 모사는 새로운 공장을 설계하기 전에 타당성 조사와 여러 가지 사례조사를 실시할 때, 기존 공 장의 개조나 증설 또는 기존 공장의 운전조건을 실제로 변경하기 전에도 미리 모사를 함으로써 실제 시험 운전을 하는 경우 보다 많은 비용과 시간을 절약할 수 있다. 본 연 구는 백상지 생산 공정 설계도면을 참고하여 상용 시율레이터로 시율레이션 모델을 구 축하고 이를 기반으로 지절 상황을 모사하였으며, 지절 후의 공정 불안정화 상황을 파 악하였다. 또한 이러한 상황의 대책을 강구하기 위해 다양한 공정 조절 방안을 시율레이션 모댈에 적용하여 그 결과를 해석하였다.

• Korean Journal of Microbiology
• /
• v.34 no.4
• /
• pp.236-242
• /
• 1998

While bacteriophage P2-P4 system is very useful experimental tool for the study of viral capsid assembly, there is no useful plasmid vector for the DNA manipulation in bacteriophage P2-P4 system. In this study, a new vector plasmid, P4 ash8 (sid71) kmr, was constructed by swapping the non-essential region of P4 DNA for kanamycin resistance(kmr) gene cassette of plasmid pUC4-K. P4 ash8 sid71 was starting material for the construction, since it tends to be maintained as a plasmid in the absence of the helper phage. The total size of this chimera was designed to be packaged into P4 or P2 size heads with induction by P2 infection. The conversion of plasmid P4 ash8 (sid71) kmr to bacteriophage was proved by burst size determination experiment and CsCl buoyant equilibrium density gradient experiment. Integrase destructed P4 derivative, P4 ash8 sid71 kmr intS, was able to be constructed easily by in vitro DNA manipulation of P4 ash8 sid71 kmr. The plasmid stability experiment with P4 ash8 sid71 kmr if/tS showed that the integrase of P4 affects the stable maintenance of plasmid P4 state.

• Research in Plant Disease
• /
• v.17 no.1
• /
• pp.90-94
• /
• 2011

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice growing regions of the world. There are no effective ways of protecting rice from the disease. In this study, the bacteriophage (phage) mixtures infecting Xoo were investigated as biological control agent on BLB. The effects of pH, heat and ultraviolet on the stability of phages were investigated to check and increase the possibility of practical use in the field. Phages were rather stable between pH 5 and pH 10. The infectivity dropped sharply when the phages were incubated at $50^{\circ}C$ and more than 90% of the phages were inactivated after two minutes of ultraviolet treatment. The phages were stable for 7 days at the rice plant leaves, and the phages survived 10 times more than other treatments when mixed with skim milk. Although the skim milk increased the stability of the phages, the control efficacy was not effective. However, the phage mixtures reduced the occurrence of BLB when they were treated with Tecloftalam WP or Acibenzolar-S-methyl simultaneously. The results indicated that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

• Journal of Advanced Marine Engineering and Technology
• /
• v.30 no.3
• /
• pp.428-437
• /
• 2006

This paper attempts to derive and analyze the dynamic system of grasping a rigid object by means of two multi-degrees-of-freedom robot flngers with soft and deformable tips. It is shown firstly that a set of differential equation describing dynamics system of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. It is shown secondly that the problems of controlling both the forces of pressing object and the rotation angle of the object under the geometric constraints are discussed. In this paper. the control method for dynamic stable grasping and enhancing dexterity in manipulating things is proposed. It is illustrated by computer simulation that the control system gives the performance improvement in the dynamic stable grasping of the dual fingers robot with soft tips.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.6
• /
• pp.175-182
• /
• 1998

An advanced visual tracking and stable grasping algorithm for a moving object is proposed. The stable grasping points for a moving 2D polygonal object are obtained through the visual tracking system with the Kalman filter and image prediction technique. The accuracy and efficiency are improved more than any other prediction algorithms for the tracking of an object. In the processing of a visual tracking. the shape predictors construct the parameterized family and grasp planner find the grasping points of unknown object through the geometric properties of the parameterized family. This algorithm conducts a process of ‘stable grasping and real time tracking’.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.10a
• /
• pp.217-218
• /
• 2012

• Korean Journal of Microbiology
• /
• v.54 no.1
• /
• pp.79-80
• /
• 2018

Citrobacter freundii is a facultative anaerobic and a Gram-negative bacterium of Enterobacteriaceae family, and is an opportunistic pathogen. Bacteriophages infecting C. freundii can be an effective treatment for C. freundii infections. Here, the complete genomic sequence is announced for a lytic bacteriophage CF1 infecting C. freundii isolates.