• The Plant Pathology Journal
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• v.22 no.1
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• pp.51-62
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• 2006

Three strains of Cucumber mosaic virus (CMV) have been found to cause a lethal disease, referred to as fern leaf syndromes and mild mosaic symptoms in tomato (Lycopersicon esculentum Mill.) crops grown in Kuwait. CMV strains were detected and identified based on host range, symptomatology, serology, electron microscopy, and ribonucleic acid (RNA) electrophoresis in polyacrylamide gels. A high degree of viral genomic heterogeneity was detected among CMV strains isolated in Kuwait, with no apparent correlation to symptomatology in tomato host plants. Two different virus satellites of 'CMV associated RNA 5', designated CARNA 5, were detected in two virus strains that caused both lethal disease and mild symptoms, designated CMV-D1 and CMV-S1 respectively. CARNA5 was not detected in the third CMV strain that caused fern leaf syndromes designated CMV-F. All the three isolated strains were serologically indistinguishable from each other and may belong to one serotype according to Ouchterlony gel diffusion tests. These strains transmitted via aphids (Myzus persicae Sulz) in a non-persistent manner. Physical properties of the virus strains were very similar where thermal inactivation test showed that virus withstood heating for 10 min at $70^{/circ}$, dilution end point was $10^{-4}$, and the longevity in vitro at room temperature was less than 5 days for all virus strains. CMV-D1 and CMV-F were the most devastating diseases spreading in both greenhouse and field-grown tomato where aborted flower buds failed on fruit setting due to the viral infection. This is the first report to isolate three different strains of CMV in Kuwait.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.232-236
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• 2004

We investigated hydrogen peroxide resistance of Escherichia coli possessing acetyl xylan esterase(AxeA) of Streptomyces coelicolor A3(2). The induction of AxeA production by isopropyl-$\beta$-thiogalactoside was confirmed by SDS-polyacrylamide gel electrophoresis. The differences in growth between induced and non-induced E. coli were determined by the changes in optical density of cultures after hydrogen peroxide treatment The lethal effect of hydrogen peroxide was observed for non-induced cultures at all concentrations tested in this study (lmM, 2.5mM and 5mM). However, cultures induced for AxeA production resisted the lethal effect, except at 5mM where cells were killed irrespective of the AxeA production. The axeA induction increased survival against 1.5mM hydrogen peroxide from 59% to 74%. In addition, AxeA producing E. coli showed increased survival at $45^{\circ}C$, near maximum growth temperature. Therefore, it was concluded that AxeA conferred a cross-resistance upon the bacterium against both oxidative- and heat stress.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.3
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• pp.204-212
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• 2015

The infrared lock-on range of target aircraft plays a critical role in determining the aircraft survivability. In this investigation, the effects of various UAV engine nozzle configurations on the aircraft lock-on range were theoretically analyzed. A virtual subsonic aircraft was proposed first, based on the mission requirement and the engine performance analysis, and convergent-type nozzles were then designed. After determining thermal flow field and nozzle surface temperature distribution with the CFD code, an additional analysis was conducted to predict the IR signature. Also, atmospheric transmissivity for various latitude and seasons was calculated, using the LOWTRAN code. Finally, the lock-on and lethal envelopes were calculated for different nozzle configurations, assuming the sensor threshold of the given IR guided missile. It was shown that the maximum 55.3% reduction in lock-on range is possible for deformed nozzles with the high aspect ratio.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.45-49
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• 1968

The effect of salinities, temperatures, and turbidities on the mortality of trochophora of oyster, Crassostrea gigas, was investigated at the laboratory. 1. The trochophora of oyster, transferred from normal sea water to sea water of lower or higher salinity, lost their vital activity sooner or later. The mortalities of trochophora were $46\%$ at lower salinity of 15 ppt and $47\%$ at higher salinity of 35 ppt respectively. 2. The high temperature above $40^{\circ}C$ was lethal to trochophora in normal salinity of sea water. Especially all of them died at $45^{\circ}C$ within 30 minutes. However, low temperatures were not lethal to trochophora than higher ones. The differences between two mortality curves at 0.5-and 1-hour treatments at each level of temperatures were not statistically significant as a result of the t-test (P>0.05). 3. It was found that the heavy turbidity (1.0 per cent) did not affect the mortality of the trochophora of oyster in a short period.

• Proceedings of the KAIS Fall Conference
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• 2004.06a
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• pp.311-314
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• 2004

Toxicity test fur various synthetic lubricant oil bases derived from biodiesel was carried out. The earthworms(Eisenia fetida) were maintanied in artificial soil consisting of sand for 14 days. Eisenia fetida was cultivated at temperature of $20{\pm}2^{\circ}C$, pH 6.0 $\pm$ 0.5 and moisture of $31\~37\%$. Pentaerythritol(PE) lubricant oil base was tested for acute toxicities to Eisenia fetida. The earthworms were exposed to each lubricant oil with various concentrations of lubricant oil base. After 14 days, the number of surviving earthworms and thier weight alteration during the test period was determined. $LC_{50}$(lethal concentration when $50\%$ of the population were killed) pentaerythritol was determined to be 1,555 mg/kg soil dry weight.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.599-607
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• 1986

Acute toxicity of crude oil (WSF) on the mortality and respiration rates of Neomysis awatschensis was examined. This experiment was conducted by static and short-term bioassay procedure. In lethal test, the test animals were exposured to 8 different concentrations to determine $LC_{50}$ value (median lethal concentration). The concentrations of total hydrocarbon of 96-hr $LC_{50}$ value at $14^{\circ}C\;and\;20^{\circ}C$ were 1.01 ppm and 0.78 ppm, respectively. $LT_{50}$ (the median lethal time) also was determined. The $LT_{50}$ of 0.56 ppm was found within 100 hours, while the $LT_{50}$ of 5.6 ppm was 21 hours at $14^{\circ}C$. At $20^{\circ}C$, the $LT_{50}$ values of 0.56 ppm and 5.60 ppm were 95 hours and 17 hours, respectively. There was little difference between two temperature experiments. The effect of WSF on respiration rate was more sensitive than that on mortality, but no considerable difference was shown between different concentrations in this experiment. The results of these experiments indicated that relatively low concentration of dissolved crude oil fraction can impact on small crustacean in the marine ecosystem.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2005.04a
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• pp.5-14
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• 2005

Recently, data from several groups have raised the concept of 'checkpoint' in transcription. As capping of nascent RNA transcript is tightly coupled to RNA polymerase II transcription, we seek to obtain direct evidence that transcripiton checkpoint via capping enzyme functions in this early regulatory step. One of temperature sensitive (ts) alleles of ceg1, a guanylyltransferase subunit of the Saccharomyces cerevisiaecapping enzyme, showed 6-azauracil (6AU) sensitivity at the permissive growth temperature, which is a phenotype that is correlated with a transcription elongational defect. This ts allele, ceg1-63 also has an impaired ability to induce PUR5 in response to a 6AU treatment. However, this cellular and molecular defect is not due to the preferential degradation of the transcript attributed from a lack of guanylyltransferase activity. On the contrary, the data suggests that the guanylyltransferase subunit of the capping enzyme plays a role in transcription elongation. First, in addition to the 6AU sensitivity, ceg1-63is synthetically lethal with elongation defective mutations of the largest subunit of RNA polymerase II. Secondly, it exhibited a lower GAL1 mRNA turn-over after glucoseshut off. Third, it decreased the transcription read through a tandem array of promoter proximal pause sites in an orientation dependent manner. Interestingly, this mutant also showed lower pass through a pause site located further downstream of the promoter. Taken together, these results suggest that the capping enzyme plays the role of an early transcription checkpoint possibly in the step of the reversion of repression by stimulating polymerase to escape from the promoter proximal arrest once RNA becomes appropriately capped.

• The Korean Journal of Pharmacology
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• v.2 no.1 s.2
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• pp.83-97
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• 1966

Attempts have been made upon the temperature response of the rat induced by some central nervous system depressants as well as stimulants, so as to secure some hidden facets of Panax Ginseng acting upon central nervous system. Although considerable works have been done with regard to Panax Ginseng, it is quite apparent that neither definite implication in terms of its effective chemical constituents is with us nor its pharmacological activity thus far. The author could, however, arrive at some results through procedures preceded by intraperitoneal administration of various drugs in combination with Panax Ginseng in albino rats, that is: (1) Nembutal and chlorpromazine displayed a highly inhibitory effect upon temperature response in the presence of Panax Ginseng, while meprobamate, reserpine, phenacetin and aspirin exerted potentiation actions upon hypothermia. Phenobarbital, serotonin and histamine, on the contrary, did not appear to produce any effect of significance. (2) Nembutal with Panax Ginseng caused prolongation of hypnosis in rat, whereas sodium phenobarbital did not have any effect on it. (3) $LD_{-50}$ in each experimental group of administration of central nervous system stimulants such as strychnine, picrotoxin with Panax Ginseng, necessitated marked increase in the lethal doses. The observations from this study seemed to imply that the complicated mechanism of action of Panax Ginseng might be referred to both central nervous depressive action and influence to basal metabolic rate of mammalian.

• Korean Journal of Pharmacognosy
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• v.24 no.2
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• pp.177-182
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• 1993

The pericarp of Cornus officinalis is well known famous medicinal drug in oriental countries. In this work, we have tried to evaluate the toxicity and also to find the lectin components from this seed. The lyophilized seed extract was lethal to experimental mouse at $250{\sim}300mg/kg$ and this toxic components were related to proteins. The lectins components were partially purified from the extract by ion exchange column chromatography. These lectins were relatively stable at temperature variations and also stable at pH $4{\sim}7$. The activity of these lectins did not inhibit by common carbohydrates molecules.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.1
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• pp.37-40
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• 2003

The antibacterial action of violet pigment, a mixture of violacein and deoxyviolacein, isolated from phychrotrophic bacterium RT102 strain was examined, and the operational conditions for the effective production of violet pigment were studied. The antibacterial activity of the violet pigment was confirmed for several bacteria such as Bacillus licheniformis, Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, and Pseudomonas aeruginosa, and the high concentration of violet pigment, above about 15mg/L, caused not only growth inhibition but also death of cells. The growth properties of RT102 strain were clarified under various incubation conditions such as pH, temperature, and dissolved oxygen concentration. The maximum violet pigment concentration, i.e. 3.7 g/L, and the maximum productivity of violet pigment, i.e. 0.12 g .L$\^$-1/H$\^$-1/, were obtained in a batch culture of pH 6, 20$^{\circ}C$, and 1 mg/L of dissolved oxygen concentration.