• Title/Summary/Keyword: Strain-control

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A Plant Growth-Promoting Pseudomonas fluorescens GL20: Mechanism for Disease Suppression, Outer Membrane Receptors for Ferric Siderophore, and Genetic Improvement for Increased Biocontrol Efficacy

  • LIM, HO SEONG;JUNG MOK LEE;SANG DAL KIM
    • Journal of Microbiology and Biotechnology
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    • v.12 no.2
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    • pp.249-257
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    • 2002
  • Pseudomonas fluorescens GL20 is a plant growth-promoting rhizobacterium that produces a large amount of hydroxamate siderophore under iron-limited conditions. The strain GL20 considerably inhibited the spore germination and hyphal growth of a plant pathogenic fungus, Fusarium solani, when iron was limited, significantly suppressed the root-rot disease on beans caused by F. solani, and enhanced the plant growth. The mechanism for the beneficial effect of strain GL20 on the disease suppression was due to the siderophore production, evidenced by mutant strains derived from the strain. Analysis of the outer membrane protein profile revealed that the growth of strain GL20 induced the synthesis of specific iron-regulated outer membrane proteins with molecular masses of 85- and 90 kDa as the high-affinity receptors for the ferric siderophore. In addition, a cross-feeding assay revealed the presence of multiple inducible receptors for heterologous siderophores in the strain. In order to induce increased efficacy and potential in biological control of plant disease, a siderophore-overproducing mutant, GL20-S207, was prepared by NTG mutagenesis. The mutant GL20-S207 produced nearly 2.3 times more siderophore than the parent strain. In pot trials of beans with F. solani, the mutant increased plant growth up to 1.5 times compared with that of the parent strain. These results suggest that the plant growth-promoting P. fluorescens GL20 and the genetically bred P. fluorescens GL20-S207 can play an important role in the biological control of soil-borne plant diseases in the rhizosphere.

Stress-strain behaviour of reinforced dredged sediment and expanded polystyrenes mixture under cyclic loading

  • Zhou, Yundong;Li, Mingdong;Wen, Kejun;Tong, Ruiming
    • Geomechanics and Engineering
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    • v.17 no.6
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    • pp.507-513
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    • 2019
  • Reinforced soil and Expanded Polystyrenes (EPS) mixture (RSEM) is a geomaterial which has many merits, such as light weight, wide strength range, easy for construction, and economic feasibility. It has been widely applied to improve soft ground, solve bridge head jump, fill cavity in pipeline and widen highway. Reutilizing dredged sediment to produce RSEM as earthfill can not only consume a large amount of waste sediment but also significantly reduce the construction cost. Therefore, there is an urgent need understand the basic stress-strain characteristics of reinforced dredged sediment-EPS mixture (RDSEM). A series of cyclic triaxial tests were then carried out on the RDSEM and control clay. The effects of cement content, EPS beads content and confining pressure on the cyclic stress-strain behaviour of RDSEM were analyzed. It is found that the three stages of dynamic stress-strain relationship of ordinary soil, vibration compaction stage, vibration shear stage and vibration failure stage are also applicative for RDSEM. The cyclic stress-strain curves of RDSEM are lower than that of control clay in the vibration compaction stage because of its high moisture content. The slopes of backbone curves of RDSEMs in the vibration shear stage are larger than that of control clay, indicating that the existence of EPS beads provides plastic resistance. With the increase of cement content, the cyclic stress-strain relationship tends to be steeper. Increasing cement content and confining pressure could improve the cyclic strength and cyclic stiffness of RDSEM.

Application of Statistical Analysis to Analyze the Spatial Distribution of Earthquake-induced Strain Data (지진유발 변형률 데이터의 분포 특성 분석을 위한 응용통계기법의 적용)

  • Kim, Bo-Ram;Chae, Byung-Gon;Kim, Yongje;Seo, Yong-Seok
    • The Journal of Engineering Geology
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    • v.23 no.4
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    • pp.353-361
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    • 2013
  • To analyze the distribution of earthquake-induced strain data in rock masses, statistical analysis was performed on four-directional strain data obtained from a ground movement monitoring system installed in Korea. Strain data related to the 2011 Tohoku-oki earthquake and two aftershocks of >M7.0 in 2011 were used in x-MR control chart analysis, a type of univariate statistical analysis that can detect an abnormal distribution. The analysis revealed different dispersion times for each measurement orientation. In a more comprehensive analysis, the strain data were re-evaluated using multivariate statistical analysis (MSA) considering correlations among the various data from the different measurement orientations. $T_2$ and Q-statistics, based on principal component analysis, were used to analyze the time-series strain data in real-time. The procedures were performed with 99.9%, 99.0%, and 95.0% control limits. It is possible to use the MSA data to successfully detect an abnormal distribution caused by earthquakes because the dispersion time using the 99.9% control limit is concurrent with or earlier than that from the x-MR analysis. In addition, the dispersion using the 99.0% and 95.0% control limits detected an abnormal distribution in advance. This finding indicates the potential use of MSA for recognizing abnormal distributions of strain data.

Parametric Analysis on the Viral Infection in The Rat Circardian Control Center (흰쥐의 일주기조절중추내 바이러스 감염에 대한 매개변수 분석)

  • Kim Jin-Sang
    • The Journal of Korean Physical Therapy
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    • v.10 no.2
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    • pp.113-125
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    • 1998
  • The neurotropic psudorabies virus(PRV) to replicate within neurons is very useful pathogen for neuronal tracing. I carried out this study to investigate the parametric analysis on the viral infection in the rat circadian control center with two genetically engineered strains out of PRV. The two strains are isogenic with the attenuated Bartha strain of PRV ; in one strain a lacZ reporter gene was inserted into the gC locus (PRV-BaBlu ; $4.75\times10^8pfu/ml$) and the other strain contained a PRV envelope glycoprotein gene(PRV-D ; $2.5\times10^8pfu/ml$) theat is absent in PRV-BaBlu. simultaneous or temporally separated sequential injection of$2{\mu}l$ of each strain into the vetreous body of eye produced a course of transsynaptic infection of retinohypothalamic circuitry. The results were as follows; 1. PRV-BaBlu and PRV-D infected the suprachiasmatic nucleus in hypothalamus and intergeniculate leaflet in lateral geniculate nucleus of thalamus. 2. The rate of PRV infection was dependent upon PRV strain. 3. Pre-infected neurons by PRV-D were interfered with the replication of PRV-BaBlu. 4. Dual injection of PRV-D and PRV-BaBlu showed more virulent than the parental strain.

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Complete genome sequence of serotype 3 Streptococcus suis INT-01, isolated from a domestic pig in Korea

  • Park, Seon Young;Kim, In Hwang;Yu, Hyun Jin;Paik, Hyoung Rok;Son, Jee Soo;Kim, Ji Hyung
    • Journal of Animal Science and Technology
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    • v.63 no.3
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    • pp.662-665
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    • 2021
  • Streptococcus suis is a major pig pathogen causing severe economic losses to the swine industry. This study aimed to analyze the genome of S. suis strain INT-01 isolated from a domestic pig in Korea. We found that the genome of strain INT-01 contains 2,092,054 bp, with a guanine (G) + cytosine (C) content of 41.3%, and the capsular polysaccharide synthesis locus of this strain is almost identical to that of serotype 3 S. suis strain 4961 isolated from China, suggesting that these isolates can be classified as serotype 3. Genomic analyses revealed that strain INT-01 is an extracellular protein factor (epf)-/ muraminidase-released protein (mrp)+/ suilysin (sly)- S. suis, which is the most prevalent genotype in Korea, and several virulence-related genes associated with the pathogenicity of S. suis were also detected. The genomic information of strain INT-01 may provide important insights into the development of control strategies against S. suis infections in Korea.

Biological Control of Arge Captiva, Arge Pagana Papana, and Arge Similis with Entomopathogenic Nematodes (곤충병원성 선충을 이용한 홍가슴루리등에잎벌(Arge captiva), 장미등에잎벌(Arge pagana papana) 및 극동등에잎벌(Arge similis)의 생물적 방제)

  • Yang, Jae Yun;Kim, Hyeong Hwan;Lee, DongWoon;Lee, Sang Myeong;Shin, Hyeon Chul;Choo, Ho Yul
    • Journal of Korean Society of Forest Science
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    • v.96 no.1
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    • pp.1-6
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    • 2007
  • Entomopathogenic nematodes (Heterorhabditis sp. Gyeongsan strain, Steinernema carpocapsae GSN1 strain, S. feltiae Monteri strain, S. glaseri Dongrae strain, S. longicaudum Nonsan strain and S. monticolum Jiri strain) were evaluated for the environmentally sound control of sawfly, Arge captiva, A. pagana pagana and A. similis in the laboratory and pot. The corrected mortality of 3rd instar of Arge captiva larva was 100% at 5 days after treatment with S. carpocapsae GSN1 strain and S. feltiae Monteri strain in Petri dish. The mean numbers of established infective juveniles (Ijs) of S. glaseri Dongrae and S. carpocapsae GSN1 strain in a Arge captiva larva were 10.2 and 4.2 Ijs/larva, respectively. Pathogenicity of S. carpocapsae GSN1 strain was different larval stage, i.e., $LC_{50}$ value of S. carpocapsae GSN1 strain against 2nd, 3rd and 4th instar of A. pagana pagana was 11.5, 9.3, and 8.4 Ijs, respectively. Mortality of Arge captiva, A. pagana pagana and A. similis were 72.5, 85.0 and 85.0% by S. carpocapsae GSN1 strain at the $2{\times}10^9Ijs/ha$, respectively, in the pot.

Development of Optical Strain Sensor with Nanostructures on a Poly-dimethylsiloxane (PDMS) Substrate (Poly-dimethylsiloxane (PDMS) 기판 위에 형성된 나노구조를 이용한 시각 인장센서의 개발)

  • Kim, Geon Hwee;Woo, Hyeonsu;Lim, Geunbae;An, Taechang
    • Journal of Sensor Science and Technology
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    • v.27 no.6
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    • pp.392-396
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    • 2018
  • Structural color has many advantages over pigment based color. In recent years, researches are being conducted to apply these advantages to applications such as wearable devices. In this study, strain sensor, a kind of wearable device, was developed using structural color. The use of structural color has the advantage of not using energy and complex measuring equipment to measure strain rate. Wrinkle structure was fabricated on the surface of Poly-dimethylsiloxane (PDMS) and used it as a sensor which color changes according to the applied strain. In addition, a transmittance-changing sensor was developed and fabricated by synthesizing additional glass nanoparticles. Furthermore, a strain sensor was developed that is largely transparent at the target strain and opaque otherwise.

Sensor and actuator design for displacement control of continuous systems

  • Krommer, Michael;Irschik, Hans
    • Smart Structures and Systems
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    • v.3 no.2
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    • pp.147-172
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    • 2007
  • The present paper is concerned with the design of distributed sensors and actuators. Strain type sensors and actuators are considered with their intensity continuously distributed throughout a continuous structure. The sensors measure a weighted average of the strain tensor. As a starting point for their design we introduce the concept of collocated sensors and actuators as well as the so-called natural output. Then we utilize the principle of virtual work for an auxiliary quasi-static problem to assign a mechanical interpretation to the natural output of the sensors to be designed. Therefore, we take the virtual displacements in the principle of virtual work as that part of the displacement in the original problem, which characterizes the deviation from a desired one. We introduce different kinds of distributed sensors, each of them with a mechanical interpretation other than a weighted average of the strain tensor. Additionally, we assign a mechanical interpretation to the collocated actuators as well; for that purpose we use an extended body force analogy. The sensors and actuators are applied to solve the displacement tracking problem for continuous structures; i.e., the problem of enforcing a desired displacement field. We discuss feed forward and feed back control. In the case of feed back control we show that a PD controller can stabilize the continuous system. Finally, a numerical example is presented. A desired deflection of a clamped-clamped beam is tracked by means of feed forward control, feed back control and a combination of the two.

Development of strain-specific polymerase chain reaction primers to detect Fusobacterium hwasookii strains

  • Lim, Yun Kyong;Kook, Joong-Ki
    • International Journal of Oral Biology
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    • v.46 no.4
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    • pp.155-159
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    • 2021
  • This study aimed to develop strain-specific polymerase chain reaction (PCR) primers to detect Fusobacterium hwasookii KCOM 1249T, F. hwasookii KCOM 1253, F. hwasookii KCOM 1256, F. hwasookii KCOM 1258, and F. hwasookii KCOM 1268 on the basis of nucleotide sequences of a gene specific to each strain. The unique genes for each F. hwasookii strain were determined on the basis of their genome sequences using Roary. The strain-specific PCR primers based on each strain-specific gene were designed using PrimerSelect. The specificity of each PCR primer was determined using the genomic DNA of the 5 F. hwasookii strains and 25 strains of oral bacterial species. The detection limit and sensitivity of each strain-specific PCR primer pair were determined using the genomic DNA of each target strain. The results showed that the strain-specific PCR primers correspond to F. hwasookii KCOM 1249T, F. hwasookii KCOM 1253, F. hwasookii KCOM 1258, F. hwasookii KCOM 1256/F. nucleatum subsp. polymorphum KCOM 1260, or F. hwasookii KCOM 1268/Fusobacterium sp. oral taxon 203 were developed. The detection limits of these strain-specific PCR primers ranged from 0.2 to 2 ng of genomic DNA for each target strain. The results suggest that these strain-specific PCR primers are valuable in quality control for detecting specific F. hwasookii strains.

Antibiotic Resistance of Salmonella spp. After Exposure to Mild Heat Treatment (살모넬라 균주들에서 열처리에 의한 항생제 내성 연구)

  • Su-Jin Kim;Woo-Suk Bang;Se-Hun Kim
    • Journal of Food Hygiene and Safety
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    • v.39 no.1
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    • pp.1-8
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    • 2024
  • Salmonella is widely prevalent in various environments and often detected in poultry. In this study, we investigated the effect of heat treatment on heat resistance via measuring the minimum inhibitory concentration (MIC) values of antibiotics after 3, 6, and 9 min of acclimatization to mild heat treatment (50℃) against 11 strains of Salmonella spp. Most strains were susceptible to chloramphenicol and their MIC values were maintained or decreased after heat treatment compared to the control. Most control and heat-treated strains showed susceptibility or intermediate resistance to ciprofloxacin. All isolates were susceptible to tetracycline, with the MIC increasing after heat treatment for S. Gaminara BAA 711. In the control, three, two, and six strains were susceptible, intermediate resistance, and resistant to gentamicin, respectively. Among them, S. Heidelberg ATCC 8326 had an intermediate MIC breakpoint of 8 ㎍/mL in the control; however, after 3 and 9 min of heat treatment, the MIC value increased to 16 ㎍/mL, indicating it to be resistant. The results of this study revealed the changes in antibiotic resistance in some of the 11 strains after heat treatment. MIC values of ciprofloxacin increased when S. Montevideo BAA 710 was heat treated for 3 and 6 min. MIC values of gentamicin increased after 3 min of heat treatment for S. Enteritidis 109 D1 and after 3 and 9 minutes of heat treatment for S. Heidelberg ATCC 8326. The MIC value of tetracycline increased when S. Gaminara BAA 711 was heat treated for 6 and 9 min.