• Research in Plant Disease
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• v.22 no.4
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• pp.227-235
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• 2016

Plant disease caused by root-knot nematode is a major problem in crop production. Using of chemical pesticides, one of the most efficient methods to control nematodes, have raised issues in toxicity to humans and animals and environmental pollution. In this study, to select actinomycete strains that have potential to serve as a microbial agent for control of nematodes, we investigated nematicidal activity of culture broth from 670 Streptomyces isolates. A culture filtrate of KRA15-528 isolate that was identified as S. flavogriseus on the basis of 16S rRNA sequence analysis, showed strong nematicidal activity against second stage of juveniles of Meloidogyne incognita and inhibited egg hatching; exposure to 10% of culture filtrate resulted in 71% juvenile mortality at 48 hours afters treatment and suppressed egg hatching by 54% at 9 days after treatment. When the KRA15-528 culture filtrate was partitioned with ethyl acetate and butanol, ethyl acetate layer exclusively showed strong activity; 91%, 53%, 30% of mortality at 1,000, 500, $250{\mu}g/ml$, respectively. Additionally, the culture filtrate suppressed gall formation on cucumber plant by M. incognita with no phytotoxicity. These results suggest that S. flavogriseus KRA15-528 has potential to serve as a microbial nematicide for the control of root-knot nematode disease.

• Research in Plant Disease
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• v.12 no.3
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• pp.298-302
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• 2006

An isolate of Cucumber mosaic virus(CMV), called as Can-CMV, was originally isolated from Canna generalis showing typical streak mosaic foliar symptoms, and its properties were investigated in this study. Whereas all known isolates of CMV could induce symptoms on their systemic hosts(four kinds of Nicotiana spp and a zucchini squash), Can-CMV induced no symptoms on its systemic hosts tested. Replication and movement of the virus on upper leaves as well as inoculated leaves-were confirmed by RT-PCR suggesting that Can-CMV could only infect systemically on N. benthamiana and N. glutinosa. Size of local lesions on the Can-CMV-inoculated leaves of Chenopodium amaranticolor was much smaller than that of Fny-CMV. Whereas Fny-CMV and LS-CMV could induce distinct necrotic local lesions on Vigna unguiculata 2 to 3 days postinoculation(dpi), chlorotic spots symptom was expressed by Can-CMV 4 to 5 dpi. Virus-specific 4 kinds of dsRNAs were isolated from leaves of N. benthamiana infected with Can-CMV, and these dsRNAs corresponded to the viral genomic RNAs and subgenomic RNAs and their patterns were indistinguishable to those of Fny-CMV and LS-CMV. By restriction mapping analysis of 950 bp of RT-PCR amplified products of coat protein gene of the virus as well as by serological analysis of gel diffusion test, Can-CMV belongs to a typical member of CMV subgroup IA. These results suggest that the Can-CMV isolated from C. generalis possesses unique pathological properties to understand further insight into the various interactions between virus and host.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.8 no.2
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• pp.202-212
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• 2005

Purpose: Transfusion transmitted virus (TTV) is a newly discovered virus and to date the contribution of TTV to liver disease remains unclear. Little is known about the frequency of TTV infection in children in Korea. The purpose of this study was to investigate the prevalence and genotypic distribution of TTV carried by healthy children and patients with hepatitis in Korea. Methods: Eighty eight of healthy children and three groups of patients with hepatitis-14 patients with chronic hepatitis B, 12 patients with chronic hepatitis C and 25 patients with hepatitis of unknown etiology-were tested. TTV DNA was detected by semi-nested PCR using primer sets generated from N-22 region and from 5' noncoding region (NCR) of the viral genome. PCR products derived from 8 patients with hepatitis and from 11 healthy children were sequenced and a phylogenetic tree was constructed. Results: TTV was found by PCR with N22 primer in 11.3% of healthy children, 28.5% of children with hepatitis B, 25% of children with hepatitis C, 24% of children with hepatitis of unknown etiology. TTV DNA was found by PCR with 5'NCR primer in 32.9% of healthy children, 71.4% of patients with chronic hepatitis B, in 50% of patients with hepatitis C and in 48% of patients with hepatitis of unknown etiology. TLMV DNA was found in 48.9% of healthy children, 21.4% of patients with hepatitis B, 16.6% of patients with hepatitis C, 40% of patients with hepatitis of unknown etiology. Among the sequenced isolates, 10(52%) belonged to genotype 1 (G1) and others belonged to genotype 2 (G2) or genotype 3 (G3). Among the G1 sequences, 7 were grouped as G1a. Conclusion: TTV infection was common in healthy children and in patients with hepatitis. But, the prevalence of TTV DNA by 5'NCR primer was relatively high in patients with hepatitis B and there may be some association between TTV and hepatitis B virus infection. G1 was the major genotype of the studied population.

• Pediatric Infection and Vaccine
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• v.5 no.2
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• pp.258-266
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• 1998

Purpose : Cases of adenoviral penumonia with rapidly progressive clinical course were experienced. We reviewed these patients in viewpoint of clinical manifestation and adenoviral serotypes. Methods : Culture and indirect immunofluorescence for respiratory viruses including respiratory syncytial virus, influenza virus, parainfluenza virus, adenovirus was done with nasopharyngeal aspirates from patients who admitted due to respiratory infections in Fatima Hospital, Masan from Nov. 1996 to Jul. 1997. Cultured adenovirus was serotyped by both neutralization and hemagglutination inhibition test. Medical records were reviewed for 5 patients with respiratory failure from adenovirus was isolated and serotyped. Results : The total number of examined patients was 460 patients. We isolated respiratory viruses in 143(30.9%) patients. Adenovirus was isolated from 66 out of 143(46.2%) patients. During Jan 1997 to May 1997, five patients with ages of 18 days to 11 months who were infected by adenovirus and had high fever with dyspnea and required assisted mechanical ventilation. One patients discharged against doctor's advice then died. Two of four patients had complications of disseminated intravascular coagulation; two had bronchiolitis obliterans. Two isolates were serotype 7, and one was serotype 5, and two were untyped. Conclusion : Severe pneumonia caused by serotype 7 continued to occur in 1997 following the epidemic in 1996, and severe pneumonia may also be caused by serotype 5 and other serotypes.

• Tuberculosis and Respiratory Diseases
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• v.53 no.6
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• pp.635-643
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• 2002

Background : The Aim of this study was to compare the recovery of mycobacteria from sputum samples of pulmonary tuberculosis patients using the MB/BacT rapid culture system(Organon Teknika, USA) with that obtained using Lowenstein-Jensen solid medium. Methods : The two culture systems were compared using sputum samples of 99 pulmonary tuberculosis patients. Culture media were incubated at $35-37^{\circ}C$ for six weeks in the MB/BacT system and for 12 weeks in Lowenstein-Jensen solid medium. Solid media were examined macroscopically once a week, and the MB/BacT system positive vials were unloaded from the machine as soon as possible after positive signal from the connected computer was detected Confirmation of growth for mycobacteria was done by Ziehl-Neelson stained smears. Isolates were identified to differentiate Mycobacterium tuberculosis from mycobacterium other than tuberculosis(MOTT) by phenotypic and molecular methods. Results : Of the sputum samples of the 99 patients, 58 samples were smear positive and 41 in negative smear. Mycobacteria were recovered from 67(67.7%) samples by using both culture systems. The yield with MB/BacT was higher than that with Lowenstein-Jensen [67(67.7%) vs. 52(52.5%), p<0.001]. Moreover, 15(15.2%) samples were positive only in the MB/BacT, whereas none of samples was positive only in Lowenstein-Jensen. In smear-positive and smear-negative samples, the recovery rate with MB/BacT was also higher than that with Lowenstein-Jensen [sputum-positive; 56/58(96.6%) vs. 46/58(79.3%), p=0.005, sputum-negative; 6/41(14.6%) vs. 5/41(12.2%), p<0.001]. The mean times to detection of Mycobacteria were 13.3 and 27.2 days with MB/BacT and Lowenstein-Jensen respectively(p<0.001). Conclusion : This results indicate that the the MB/BacT is more efficient and faster than Lowenstein-Jensen for the recovery of mycobacteria.

• Journal of Mushroom
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• v.2 no.3
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• pp.115-126
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• 2004

Somatic hybrids of inter-compatible and inter-incompatible strains were obtained by protoplast fusion. The fusion products between compatible strains, Pleurotus ostreatus and P. florida, formed heterokaryons, while fusants between incompatible strains such as P. cornucopiae + P. florida, P. ostreatus + Ganoderma applanatum, P. florida + Ganoderma lucidum, and P. ostreatus + Flammulina velutipes formed synkaryons that retained genes from both parents. The heterokaryons showed the same level of basidioma development. In contrast, the synkaryons showed unique characteristics including clamp connection formation at mitosis, either partner basidioma development, and abnormal segregation and recombination compared with inter-compatible strains. Synkaryons can be classified into homokaryoyic and heterokaryotic type. A comparison of somatic hybrids with compatible and incompatible strains was made using random amplified polymorphic DNA (RAPD) analysis. The heterokaryons between compatible species showed the same level of variability and contained both parental RAPD bands. In contrast, most of the synkaryons between incompatible species showed similarity to those of either parental bands and non-parental RAPD bands. Synkaryons can be classified into microgenome insertion type and macrogenome insertion type. A tetrapolar mating system was found among monospore isolates in somatic hybrids and wild type P. ostreatus. Homokaryons from each somatic hybrid combination were paired with tester homokaryons of the initial wild type of P. ostreatus. The changed mating types were identified in progenies. The pattern of mating type switching in somatic hybrids depends on compatibility of fusion partner. There are several factors related to the mechanism of clamp connection formation and fruiting body development of synkaryons. Of these,the major factor may be associated with self-fertility and mating type switching such as homokaryotic fruiting of wild type P. ostreatus. This review will discuss these aspects.

• Restorative Dentistry and Endodontics
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• v.27 no.5
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• pp.463-472
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• 2002

Bacterial lipopolysaccharide (LPS) plays a major role in stimulating the synthesis and release of the principal osteoclast-activating cytokines, namely, interleukin 1 and tumor necrosis factor-$\alpha$ from immune cells. Although rnonocytes/macrophages are the main producers of these cytokines, recent evidence has indicated that polymorphonuclear leukocytes (PMN) have the ability to release IL-1 and TNF-$\alpha$. Calcium hydroxide has been shown to be an effective medicament in root canal infections, reducing the microbial titre within the canal. It has been proposed that the therapeutic effect of Ca(OH)$_2$ may also be the result of direct inactivation of LPS. The purpose of this study was to investigate whether treatment of Porphyromonas endodontalis LPS with calcium hydroxide alters its biological action as measured by human PMN secretion of IL-1 and TNF-$\alpha$, and it was compared with Escherichia coli LPS. P. endodontalis ATCC 35406 was cultured in anaerobic condition, and LPS was extracted using the hot-phenol water extraction method and purified. Purchased E. coli LPS was also purified. 100 $\mu\textrm{g}$/ml of each LPS in pyrogen free water were incubated with 25mg/ml Ca(OH)$_2$ at 37$^{\circ}C$ for 7 days. The supernatants were subjected to ultrafiltration, and the isolates were lyophilized and weighed. PMNs were obtained from peripheral blood by centrifugation layered over Lymphoprep. The cells were resuspended (4$\times$10$^6$ cells/ml) in RPMI 1640 followed by treatment with various concentrations of LPS (0, 0.1, 1, 10$\mu\textrm{g}$/ml) for 24 hours at 37$^{\circ}C$ in 5% $CO_2$ incubator. The supernatants of cells were collected and the levels of IL-1$\alpha$, IL=1$\beta$ and TNF-$\alpha$ were measured by enzyme-linked immunosorbent assay. The results were as follows ; 1. The levels of IL-1$\alpha$, IL-1$\beta$, TNF-$\alpha$ from PMN treated with each LPS were significantly higher than those released from unstimulated PMN of the control group (p<0.05). 2. The levels of all three cytokines released from PMN stimulated with each calcium hydroxide treated LPS were significantly lower than those released from PMN stimulated with each untreated LPS (p<0.05), while they were not significantly different from those released from unstimulated PMN of the control group (p>0.05) 3. The levels of secretion for all three cytokines were affected in a dose-dependent manner in PMN stimulated with each LPS (p<0.05), but not in PMN stimulated with each calcium hydroxide treated LPS (p>0.05). 4. The levels of all three cytokines released from PMN stimulated with p. endodontalis LPS were significantly lower than those released from PMN stimulated with E coli LPS (p<0.05).

• Clinical and Experimental Pediatrics
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• v.45 no.11
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• pp.1368-1372
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• 2002

Purpose : Group A streptococci have a cell wall which consists of M protein and T protein. T protein is known to be helpful in the understanding of the epidemiology of group A streptococci. To study the epidemiologic characteristics, we serotyped T protein of group A streptococci obtained from patients admitted to hospitals, or who visited OPD in five districts of Seoul the during last three years. Methods : Group A streptococci were obtained in five districts in north, northeast, central, northwest and south Seoul from 1998 through 2000. All isolated group A streptococci were serotyped with T protein antisera(Institute of Sera and Vaccine, Prague, Czech Republic). Results : In 1998, analysis of obtained total number of 92 strains revealed that T12, T4, and NT acounted for 72.2%. Among seven cases of scarlet fever, T12 was isolated in four cases and T4 was found in three cases. Two cases of tonsilar abscess produced T8 and NT. One case of cervical lymphadenitis showed T12. In 1999, 41 cases were studied showing that T12, T4, and T1 contributed 68%. Among five cases of scarlet fever, T12 and T4 make up three case. There were two cases of pneumonia(T4 and T1) and one case of cervical lymphadenitis(T8/25). In 2000, the study was performed in four districts except the central area. Among 83 isolates, T12, T4 and T1 accounted for 63.9%. There were three cases of scarlet fever(T12, T4, T5), one case of tonsillar abscess(T12), one case of pneumonia(NT) and one case of sepsis(T1). Conclusion : Serological analysis of T protein of group A streptococci shows no endemic specificity. The yearly pattern reveals that T12 had been decreasing but T1 had shown the opposite trend.

• Journal of Astronomy and Space Sciences
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• v.22 no.4
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• pp.393-408
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• 2005

We developed and compared two automatic algorithms for moving object detections in the YSTAR-NEOPAT sky survey program. One method, called starlist comparison method, is to identify moving object candidates by comparing the photometry data tables from successive images. Another method, called image subtraction method, is to identify the candidates by subtracting one image from another which isolates sources moving against background stars. The efficiency and accuracy of these algorithms have been tested using actual survey data from the YSTAR-NEOPAT telescope system. For the detected candidates, we performed eyeball inspection of animated images to confirm validity of asteroid detections. Main conclusions include followings. First, the optical distortion in the YSTAR-NEOPAT wide-field images can be properly corrected by comparison with USNO-B1.0 catalog and the astrometric accuracy can be preserved at around 1.5 arcsec. Secondly, image subtraction provides more robust and accurate detection of moving objects. For two different thresholds of 2.0 and $4.0\sigma$, image subtraction method uncovered 34 and 12 candidates and most of them are confirmed to be real. Starlist comparison method detected many more candidates, 60 and 6 for each threshold level, but nearly half of them turned out to be false detections.

• Pediatric Infection and Vaccine
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• v.11 no.1
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• pp.90-100
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• 2004

Objective : Urinary tract infection(UTI) is a frequent serious bacterial infection in young infants. The clinical presentation may be non-specific and variable, depends on factors such as the age and the level of infection. Children with renal involvement may be at risk of permanent renal damage. Experimental studies have shown that renal lesions caused by acute febrile UTI may be prevented or diminished by early diagnosis and treatment. Therefore, it is important to find a method that can permit early diagnosis and identification of patients who are at risk for progressive renal damage. We designed this study to identify related factors in culture positive UTI infants, and also to identify related factors in culture negative UTI infants, who are febrile with pyuria, by using renal imaging and functional studies including renal sonography, DMSA scan and VCUG. Methods : Retrospectively analyzed the medical records of 136 febrile infants with pyuria over 2 years(from January 2001 to February 2003). Urine culture was done in all cases, and regardless of urine culture findings, renal imaging study was done if symptomatic UTI suspected. Results : Total 57 organisms were isolated in 53 patients. E. coli was the most common organism(86%), followed by E. faecalis, M. morganii, Proteus species, P. aeruginosa, S. aureus and E. fergusonii. Most of the isolates had high sensitivity on cephalosporins or amikacin and had low sensitivities on aminopenicillins. Abnormal acute phase DMSA scan or VCUG findings were seen in both urine culture positive and negative group without statistical differences(P>0.05). In febrile infants with pyuria, fever over 48 hours, older age and high CRP related to abnormal acute phase DMSA scan findings regardless urine culture results. Conclusion : 1st or 3rd generation cephalosporins with amikacin could be the first choice of treatment for UTI. Febrile infants with positive urine culture dose mean urinary tract infection but not acute pyelonephritis which directly relates to cortical damage which could be confirmed by acute phase DMSA scan. Even cases with negative urine culture findings, acute pyelonephritis should be concerned in febrile infants with pyuria who are older than 3 months of age, has fever over 48 hours or high CRP level. And in such cases, acute phase DMSA scan and VCUG should be evaluated for early treatment and long term prognosis.