• Title, Summary, Keyword: biotype

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Isolation of Verocytotoxin Producing Escherichia coli O157:H7 Due to Fcal Contamination on Carcass Surfaces (도체표면의 분변오염과 Verotoxin 생성 Escherichia coli O157:H7 분리에 관한 연구)

  • 홍종해;고주언
    • Journal of Food Hygiene and Safety
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    • v.12 no.1
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    • pp.78-82
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    • 1997
  • Surface swab samples from beef (188), pork (240) and chicken (95) carcasses were collected from slaughterhouse in Kangwon and Kyunggi areas from March through July 1996. The samples were examined on the level of E. coli biotype I relevant to fecal contamination due to unsanitary processing control and the existence of verocytotoxin-producing E. coli (VTEC). E. coli biotype I were confirmed from 38.8% of beef, 40.0% of pork, and 69.5% of chicken carcasses. Little variation was noted among three sampling points; rump, flank and neck of beef, ham, belly and jowls of pork. coli O157:H7 was only confirmed from 2 of 188 beef carcasses. E. coli biotype I. All the isolated E. coli O157 showed positive for vero cell cytotoxicity test. Isolation rate of E. coli O157 in summer was higher than in spring. In case of pork and chicken carcasses, E. coli O157 was isolated in summer only.

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Herbicidal Response and Control of Scirpus juncoides Roxb. Resistant to Sulfonylurea Herbicides (Sulfonyurea계 제초제 저항성 올챙이고랭이(Scirpus juncoides Roxb.)의 제초제 반응과 방제)

  • Park, Tae-Seon;Kang, Dong-Kyun;Kim, Kil-Ung
    • The Korean Journal of Pesticide Science
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    • v.9 no.3
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    • pp.250-261
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    • 2005
  • This study was conducted to investigate the herbicidal response and effective control strategy of sulfonylurea(SU)-resistant Scirpus juncoides Roxb. occurred in the paddy fields of Korea. A biotype of Scirpus juncoides Roxb. resistant to SU was identified in the paddy fields treated with SU herbicide-based mixtures for seven consecutive years. The apparent SU resistance observed in Scirpus juncoides Roxb. was completely confirmed in greenhouse tests. The susceptible biotype was almost controlled at the recommended dose of all the tested, but the resistant biotype was survived 20 to 30% even at 10 times higher dose of each the recommended dose of SU herbicides. The $GR_{50}$ values of 4 SU herbicides for the resistant biotype were 53 to 88 times higher than those for the susceptible biotype. The acetolactate synthase(ALS) isolated from the resistant biotype against bensulfuron-methyl and pyrazosulfuron-ethyl was less sensitive than that of the susceptible biotype. The $I_{50}$ values of the resistant biotype against bensulfuron-methyl and pyrazosulfuron-ethyl were 498 and 126 times higher than those for the susceptible biotype. A rapid diagnosis for identifying resistance of Scirpus juncoides Roxb. was possible within at least 3 days after SU herbicides. Three herbicides having different mode of action from SU herbicide, carfentrazone-ethyl, pyrazolate and simetryne exhibited excellent controlling effects on the resistant biotype of Scirpus juncoides Roxb. till 3.5 leaf stage. Among the SU-based herbicides, pyriminobac-methyl+pyrazosulfuroil-ethyl+carfentrazone-ethyl GR and azimsulfuron+carfentrazone-ethyl+pyriminobac-methyl GR were very effective to control resistant biotype of Scirpus juncoides Roxb. without rice injury. The resistant biotype which were not controlled with SU herbicise-based herbicides survived from the fields were effectively controlled by bentazone SL.

Mechanism of Sulfonylurea Herbicide Resistance in Broadleaf Weed, Monochoria korsakowii (광엽잡초 물옥잠의 Sulfonylurea 제초제에 대한 저항성 작용기작)

  • Park, Tae-Seon;Lhm, Yang-Bin;Kyung, Kee-Sung;Lee, Su-Heon;Park, Jae-Eup;Kim, Tae-Wan;Kim, Kil-Ung
    • The Korean Journal of Pesticide Science
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    • v.7 no.4
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    • pp.239-247
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    • 2003
  • This experiment was carried out to study the resistant mechanism of sulfonylurea(SU) herbicides to Monochoria korsakowii occurring in the rice fields of Korea. The activity of acetolactate synthase(ALS), absorption and translocation of $[^{14C}]$bensulfuron-methyl, and DNA sequence of ALS genes were studied. The apparent SU resiatance to Monochoria korsakowii was confirmed in greenhouse testes. Fresh weight accumulation$(GR_{50})$ in the resistant biotype was about 5- to 64-fold higher in the presence of six SU herbicides compared to the susceptible biotype. The ALS activity isolated from the resistant biotype to herbicides tested was less sensitive than that of susceptible biotype. The concentration of herbicide required for 50% inhibition of ALS activity$(I_{50})$ was 14- to 76-fold higher as compared to the susceptible biotype. No differences were observed in the rates of $[^{14C}]$bensulfuron uptake and translocation. However, the DNA sequence from the resistant biotype differed from that of the susceptible biotype by single nucleotide substitution at three amino acid each in the middle region excluding the ends of ALS genes. We found three point mutations causing substitution of serine for threonine at amino acid 168, arginine for histidine at amino acid 189, and a aspartic acid for phenylalanine at amino acid 247, respectively, in the resistant biotype.

Preference, Development and Fecundity of the Brown Planthopper(Nilaparvata lugens St${\aa}$l) Biotypes Fed on Different Cultivars of Rice with Various Resistance Gence (벼의 품종저항성이 벼멸구 각 생태형의 선호성, 발육 및 증식능력에 미치는 영향)

  • 박영도;송유한
    • Korean journal of applied entomology
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    • v.27 no.2
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    • pp.87-93
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    • 1988
  • Some attempts were made to investigate the biological characteristics of the brown planthopper(BPH), Nilaparvata lugens St${\aa}$l, biotypes in terms of perference in feeding oviposition on rice field, egg and nymphal periods, egg hatchability, emergemce ratio, growth index, adult lingevity and gecundity fed on 60-day-old rece cultivaes with different resistance genes. Feeding and oviposition perference of the three BPH biotypes on Dongjinbyeo with no resistance gene were shown very higher than on rice cultivars with resistance genes. Those of biotype-2 on Cheongcheongbyeo with bph 1 gene and bitype-3 on Milyang 63 with bph 2 gene were relatively high, however, they were still remarkably lower than those of Dongjibyeo. The egg and nymphal periods of the three BPH biotyes on Milyang 23 were shorter than on the other rice cultivars. The periods of biotype-2 on Cheongcheongbyeo and biotype-3 on Milyang 63 were as short as those of the three BPH biotypes on Milyang 23. The egg hachability, emergence ratio, and growth index of the three BPH bioyoes on Milyang 23 were higher than on the other rice cultivars and those of biotype-2 on Cheongcheongbyeo and biotyoe-3 on Milyang 63 were as high as on Milyang 23. The female adult longevity of the BPH biotype-1 on Milyang 23 was longer than on the other cultivaes, and that of biotype-2 on Cheongcheongbyeo and bioty-3 an Milyang 63 were as ling as on Milyang 23. The number of egg laid by a female of the three BPH biotypes were greatly increased on Milyang 23. Those of biotype-2 on Cheongcheongbyeo and biotype-3 an Milyang 63 were also greatly increased.

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Influence of gingival biotype on the amount of root coverage following the connective tissue graft (치은의 biotype이 결합조직이식 후 치근피개도에 미치는 영향)

  • Joo, Ji-Young;Lee, Ju-Youn;Kim, Sung-Jo;Choi, Jeom-Il
    • Journal of Periodontal and Implant Science
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    • v.39 no.2
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    • pp.111-118
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    • 2009
  • Purpose: The integrity of interproximal hard/soft tissue has been widely accepted as the key determinant for success or degree of root coverage following the connective tissue graft. However, we reason that the gingival biotype of an individual, defined as the distance from the interproximal papilla to gingiva margin, may be the key determinant that influence the extent of root coverage regardless of traditional classification of gingival recession. Hence, the present study was performed with an aim to verify that individual gingival scalloping pattern inherent from biotype influence the level of gingival margin following the connective tissue graft for root coverage. Methods: Test group consisted of 43 single-rooted teeth from 21 patients (5 male and 16 female patients, mean age: 36.6 years) with varying degrees of gingival recession requiring connective tissue graft; 20 teeth of Miller class I and 23 teeth of Miller class III gingival recession, respectively. The control group consisted of contralateral teeth which did not demonstrate apparent gingival recession, and thus not requiring root coverage. For a biotype determination, an imaginary line connecting two adjacent papillae of a test tooth was drawn. The distance from this line to gingival margin at mid-buccal point and this distance (P-M distance) was designated as "gingival biotype" for a given individual. The distance was measured at baseline and 3 to 6 months examinations postoperatively both in test and control groups. The differences in the distance between Miller class I and III were subject to statistical analysis by using Student.s t-test while those between the test and control groups within a given patient were by using paired t-test. Results: The P-M distance at 3 to 6 months postoperatively was not significantly different between Miller class I and Miller class III. It was not significantly different between the test and control group in a given patient, either, both in Miller class I and III. Conclusions: The amount of root coverage following the connective tissue graft was not dependent on Miller's classification, but rather was dependent on P-M distance, strongly implying that the gingival biotype of a given patient may play a critical impact on the level of gingival margin following connective tissue graft.

Occurrence of the B- and Q-biotypes of Bemisia tabaci in Korea (담배가루이 B와 Q 계통의 국내 발생 상황)

  • Lee, Min-Ho;Kang, Seok-Young;Lee, Sun-Young;Lee, Heung-Su;Choi, June-Yeol;Lee, Gwan-Seok;Kim, Whang-Yong;Lee, Si-Woo;Kim, Seon-Gon;Uhm, Ki-Baik
    • Korean journal of applied entomology
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    • v.44 no.3
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    • pp.169-175
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    • 2005
  • The occurrence of tobacco whiteflies, Bemisia tabaci, in greenhouses was monitored in Korea in 2005. Bemisia tabaci occurred in the rose, sweet pepper, tomato, and cucumber greenhouses of Chungbuk, Chungnam, Gyongnam, and Jeonnam Provinces, but not in Jeonbuk and Gyongbuk Provinces. The biotypes and genetic differentiation of the whiteflies collected in each regions were analyzed by mitochondrial 16S DNA sequences. The 16S DNA sequences of Jincheon (Chungbuk Province) samples were similar to DNA data reported from Japan and Israel which were known as the B biotype. However, the DNA sequences of the Buyeo (Chungnam), Geoje (Gyongnam) and Boseong (Jeonnam) collections, which were 100% homologous showed over 99% similarity to the DNA of Q biotype from Spain and Egyrt. Here we report the first founding of the Q biotype in Korea. It is assumed that, unlike the B biotype reported from Jincheon since 1998, the Q biotype might have been introduced recently from the certain foreign region/country to the greenhouses in those provinces.

Relationship between the facial bone thickness and gingival biotype of the anterior maxilla in Koreans (한국인의 상악 전치부 순측골 두께와 치은 생체형(gingival biotype)의 상관관계)

  • Park, Ji-Hun;Kim, Yeun-Kang;Kim, Hyoung-Min;Joo, Ji-Young;Lee, Ju-Youn
    • Journal of Dental Rehabilitation and Applied Science
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    • v.31 no.3
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    • pp.169-177
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    • 2015
  • Purpose: The objects of this study were to examine the thickness of labial plate of anterior maxillary teeth and the gingival biotype in Koreans and to evaluate whether there is a correlation between the gingival biotype and the thickness of labial plate. Materials and Methods: This study was performed on 335 teeth of 57 subjects at the Pusan National University Dental Hospital. Cone Beam Computed Tomography (CBCT) was used to measure the thickness of labial plate at 4 mm, 6 mm, 8 mm from the cementoenamel junction and the gingival biotype was determined by the visibility of periodontal probe. Results: Thin facial bone less than 1 mm was observed in 87% at 4 mm, 88% at 6 mm and 90% at 8 mm. In 21% of total objects, thin gingival biotype was observed. There is no correlation between the thickness of labial plate and gingival biotype. Conclusion: Additional thorough radiographic examination such as CBCT was mandatory for aesthetic dental implant in the anterior dentition besides clinical oral examination.

Distribution of thermophilic Campylobacters in animals and transfer of drug resistance factor of isolates to related bacteria I. Distribution and drug resistance of thermophilic Campylobacters isolated from animals (동물(動物)에서의 thermophilic Campylobacter의 분포(分布) 및 분리세균(分離細菌)의 약제내성(藥劑耐性) 전달(傳達)에 관(關)한 연구(硏究) I. 동물(動物)에서 thermophilic Campylobacter의 분포(分布) 및 분리세균(分離細菌)의 약제(藥劑)에 대한 내성(耐性))

  • Kim, Yong-hwan;Mah, Jum-sool
    • Korean Journal of Veterinary Research
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    • v.29 no.3
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    • pp.291-301
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    • 1989
  • To investigate the epidemiological trait of intestinal diseases of animals caused by thermophilic Campylobacter spp., isolation of etiological agent was carried out. Isolated Campylobacter spp. were biotyped, serotyped and the susceptibility of the isolates to antimicrobial agents were examined. Th results were as follows. 1. Isolation rates of Campylobacter spp. from 649 fecal materials of 208 cattle, 300 pigs and 141 chickens were 25.5%, 23.7% and 38.3%, respectively. 2. The majority of the 130 isolates of C jejuni was classified as biotype I(50.6%) and biotype II (34.6%). Most of the 46 isolates of C coli were biotype I (71.7%). 3. Isolated C jejuni strains showed 14 different serotype, and serotype 4, 26, 36 were most frequent. Isolated C coli strains showed 5 different serotype and serotype 31 and 21 were relatively common. 4. Isolated Campylobacter spp. were highly susceptible to nalidixic acid, amikacin, gentamicin, colistin and chlorampehnocol.

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Molecular Variation of Endosymbiotic Bacteria Wolbachia in Bemisia tabaci and Related Whiteflies

  • Jahan, S.M. Hemayet;Lee, Kyeong-Yeoll
    • Current Research on Agriculture and Life Sciences
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    • v.30 no.2
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    • pp.115-123
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    • 2012
  • Whiteflies harbor several secondary endosymbionts, which are maternally inherited from mother to offspring, that have major effects on host preferences, biology, and evolution. Here, we identified Wolbachia bacteria in sweetpotato whitefly (Bemisia tabaci) as well as whitefly popluations from other countries by comparison of 16S rDNA sequences. Wolbachia were detected in all tested indigenous B. tabaci populations (Bangladesh, Myanmar, Nepal, and the Philippines) as well as Q1 biotype of Korea, whereas they were absent from B biotype of Korea and Q biotype of China. Wolbachia were also detected in all five tested Aleurodicus dispersus populations as well as Tetraleurodes acaciae, whereas they were not detected in all seven Trialeurodes vaporariorum populatuions. In addiiton, Wolbachia were detected in parasitic wasp (Encarsia formosa) of B. tabaci as well as honeybee (Apis mellifera). Among the 19 whitefly populations from different countries, our analysis identified four phylogenetic groups of Wolbachia, thereby demonstrating the high diversity of this genus. Wolbachia phylogeny suggests a correlation of geographical range with ecological variation at the species level.

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Study on the Contamination of Pseudomonas tolaasii in Oyster Mushroom (느타리버섯에서의 Pseudomonas tolaasii오염 연구)

  • 이혜영;장금일;김광엽
    • Journal of Food Hygiene and Safety
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    • v.16 no.3
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    • pp.232-240
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    • 2001
  • One hundred twenty five bacterial isolates were obtained from the brown blotch-diseased oyster mushrooms collected from markets. Among them, 45 were determined as pathogenic bacteria and white line forming organisms(WLFO) were 6 strains and white line reaction organisms (WLRO) were 6 strains. All of the white line forming isolates were identified as Pseudomonas tolaasii which is a known pathogen of brown blotch disease of oyster mushroom by GC-MIS(Gas chromatography-microbial identification system). Six of the white line reacting organisms were identified as P. chlomraphis, P. fluorescens biotype A and type C. The rest of them were P gingeri, P. agarici, P. fluorescens biotype B, P. chloroyaphis, non-pathogenic P. tolaasii, P. putida biotype A and B etc. For spectrum of activity of tolaasin, culture filtrates from pathogenic isolates were examined by browning of mushroom tissue and pitting of mushroom caps. The weak pathogenic bacteria didn't induce browning or pitting of mushroom tissue. On the other hand, strong pathogenic isolates showed browning and pitting reaction on mushroom. An extracellular toxin produced by P. tolaasii, was investigated. The hemolysis activity test of 6 strains identified as P. tolaasii were 0.8∼0.9 at 600 nm and 3 strains of WLRO were 0.9∼1.0 and Pseudomonas app. were 1.0∼1.2. Observation of fresh mushroom tissue using confocal laser scanning microscopy was carried out for images of optical sectioning and vertical sectioning. Also images of brown blotch diseased oyster mushroom tissue after contamination P. tolaasii was obtained by CLSM.

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