In vivo Pathogenicity Test of Oak Wilt Fungus (Raffaelea quercus-mongolicae) on Oriental Chestnut Oak (Quercus acutissima)

Su Hee Yi,Jin Heung Lee,Sang Tae Seo,Jong Kyu Lee 강원대학교 산림과학연구소 2017 Journal of Forest Science Vol.33 No.4

Since the first report of the oak wilt disease at 2004 in Korea, the disease distributed over Korean peninsula and are still giving severe damages. The management of oak wilt disease in Korea has mainly focused on the control of insect vector, Platypus koryoensis. Neverthless the effective method for evaluating the pathogenicity of the pathogen, Raffaelea quercus-mongolicae (Rqm), and for screening chemical or biological agents with strong inhibitory activity against the pathogen, is absolutely necessary, an reliable method is not available so far. This study was conducted to develop the effective method for evaluating the pathogenicity of Rqm in oak trees. The culture suspensions of Rqm were artificially injected to the saplings of Quercus acutissima by using ChemJet tree injector. Three months after treatments, the treated saplings were cut and dipped into 1% fuchsin acid solution. There were significant differences in non-conductive area (%), discoloration area (%) and vertical discoloration length between the pathogen-injected and distilled water-injected control treatments. These results indicated that the pathogen is the causal agent for the dysfunction of water conductive tissue, which will finally result in wilt symptom. Re-isolation of the pathogen and PCR detection using specific primers for the pathogen also confirmed the presence of Rqm in the sapwood chips of the pathogen-injected saplings. These observations would be greatly applied to other related researches for evaluating the pathogenicity of tree wilt pathogens and biocontrol efficacy of the selected antagonistic microorganisms, in case that the wilt symptom is not easily shown by artificial inoculation of the causal agent.

Effects of different NS genes of avian influenza viruses and amino acid changes on pathogenicity of recombinant A/Puerto Rico/8/34 viruses

Kim, Il-Hwan,Kwon, Hyuk-Joon,Lee, Su-Hyung,Kim, Dae-Yong,Kim, Jae-Hong Elsevier 2015 Veterinary microbiology Vol.175 No.1

<P><B>Abstract</B></P> <P>To examine the effects of the NS1 and NEP genes of avian influenza viruses (AIVs) on pathogenicity in mice, we generated recombinant PR8 viruses containing 3 different NS genes of AIVs. In contrast to the reverse genetics-generated PR8 (rPR8) strain and other recombinant viruses, the recombinant virus rPR8-NS(0028), which contained the NS gene of A/chicken/KBNP-0028/2000 (H9N2) (0028), was non-pathogenic to mice. The novel single mutations of 0028 NS1 to corresponding amino acid of PR8 NS1, G139D and S151T increased the pathogenicity of rPR8-NS(0028). The replacement of the PL motifs (EPEV or RSEV) of pathogenic recombinant viruses with that of 0028 (GSEV) did not reduce the pathogenicity of the viruses. However, a recombinant virus with an EPEV-grafted 0028 NS gene was more pathogenic than rPR8-NS(0028) but less than rPR8. The lower pathogenicity of rPR8-NS(0028) might be associated with the lower virus titer and IFN-β level in the lungs of infected mice, and be attributed to G139, S151 and GSEV-PL motif of NS1 gene of 0028. In conclusion we defined new amino acid residues of NS1 related to mice pathogenicity and the presence of pathogenic NS genes among low pathogenic AIVs may encourage continuous monitoring of their mammalian pathogenicity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A mice nonpathogenic NS gene originated from an attenuated H9N2 virus was identified. </LI> <LI> Mice pathogenic NS genes among LPAIVs were identified. </LI> <LI> Novel amino acid changes related to mice pathogenicity were identified. </LI> <LI> A method to generate nonpathogenic PR8-based recombinant virus was suggested. </LI> </UL> </P>

두 개의 새로운 phytotoxin의 Botrytis cinerea 병원성에서의 역할

김금정,윤미영,김흥태,최경자,장경수,최용호,박명수,차병진,김진철 한국식물병리학회 2009 식물병연구 Vol.15 No.2

In the course of study on the roles of phytotoxins in the pathogenicity of Botrytis cinerea, we isolated two novel phytotoxins. They were identified as 3-O-acetyl botcinol and 3-O-acetyl botcinolide. In this study, we investigated correlation between the two phytotoxins and the pathogenicity of B. cinerea. In liquid cultures, the two phytotoxins were not produced by three low pathogenic isolates out of 25 B. cinerea isolates. Among strong or moderate pathogenic isolates, some produced the two phytotoxins, but the others did not. On the other hand, the ethyl acetate extracts of fermentation broths of 10 out of 25 isolates showed phytotoxic activity against various plants tested in a whole plant assay. The phytotoxins were detected in all of the 10 phytotoxic ethyl acetate extracts. In planta, the two phytotoxins were detected in all of the plant tissues infected with strong pathogenic isolates. However, there was no correlation between the ability of B. cinerea isolates to produce the two phytotoxins and their pathogenicities. The two phytotoxins began to detect in tomato plant tissues infected with B. cinerea 2-16 at 3 days after inoculation, increased gradually till 4 days after inoculation, and then decreased. The above results suggest that 3-O-acetyl botcinol and 3-O-acetyl botcinolide are one of pathogenicity factors for B. cinerea, but not a primary determinant of its pathogenicity. In the course of study on the roles of phytotoxins in the pathogenicity of Botrytis cinerea, we isolated two novel phytotoxins. They were identified as 3-O-acetyl botcinol and 3-O-acetyl botcinolide. In this study, we investigated correlation between the two phytotoxins and the pathogenicity of B. cinerea. In liquid cultures, the two phytotoxins were not produced by three low pathogenic isolates out of 25 B. cinerea isolates. Among strong or moderate pathogenic isolates, some produced the two phytotoxins, but the others did not. On the other hand, the ethyl acetate extracts of fermentation broths of 10 out of 25 isolates showed phytotoxic activity against various plants tested in a whole plant assay. The phytotoxins were detected in all of the 10 phytotoxic ethyl acetate extracts. In planta, the two phytotoxins were detected in all of the plant tissues infected with strong pathogenic isolates. However, there was no correlation between the ability of B. cinerea isolates to produce the two phytotoxins and their pathogenicities. The two phytotoxins began to detect in tomato plant tissues infected with B. cinerea 2-16 at 3 days after inoculation, increased gradually till 4 days after inoculation, and then decreased. The above results suggest that 3-O-acetyl botcinol and 3-O-acetyl botcinolide are one of pathogenicity factors for B. cinerea, but not a primary determinant of its pathogenicity.

In vivo Pathogenicity Test of Oak Wilt Fungus (Raffaelea quercus-mongolicae) on Oriental Chestnut Oak (Quercus acutissima)

Yi, Su Hee,Lee, Jin Heung,Seo, Sang Tae,Lee, Jong Kyu Institute of Forest Science 2017 Journal of Forest Science Vol.33 No.4

Since the first report of the oak wilt disease at 2004 in Korea, the disease distributed over Korean peninsula and are still giving severe damages. The management of oak wilt disease in Korea has mainly focused on the control of insect vector, Platypus koryoensis. Neverthless the effective method for evaluating the pathogenicity of the pathogen, Raffaelea quercus-mongolicae (Rqm), and for screening chemical or biological agents with strong inhibitory activity against the pathogen, is absolutely necessary, an reliable method is not available so far. This study was conducted to develop the effective method for evaluating the pathogenicity of Rqm in oak trees. The culture suspensions of Rqm were artificially injected to the saplings of Quercus acutissima by using ChemJet tree injector. Three months after treatments, the treated saplings were cut and dipped into 1% fuchsin acid solution. There were significant differences in non-conductive area (%), discoloration area (%) and vertical discoloration length between the pathogen-injected and distilled water-injected control treatments. These results indicated that the pathogen is the causal agent for the dysfunction of water conductive tissue, which will finally result in wilt symptom. Re-isolation of the pathogen and PCR detection using specific primers for the pathogen also confirmed the presence of Rqm in the sapwood chips of the pathogen-injected saplings. These observations would be greatly applied to other related researches for evaluating the pathogenicity of tree wilt pathogens and biocontrol efficacy of the selected antagonistic microorganisms, in case that the wilt symptom is not easily shown by artificial inoculation of the causal agent.

Simple and label-free pathogen enrichment via homobifunctional imidoesters using a microfluidic (SLIM) system for ultrasensitive pathogen detection in various clinical specimens

Jin, Choong Eun,Koo, Bonhan,Lee, Eun Yeong,Kim, Ji Yeun,Kim, Sung-Han,Shin, Yong Elsevier 2018 Biosensors & bioelectronics Vol.111 No.-

<P><B>Abstract</B></P> <P>Diseases caused by pathogenic microorganisms including bacteria and viruses can cause serious medical issues including death and result in huge economic losses. Despite the myriad of recent advances in the rapid and accurate detection of pathogens, large volume clinical samples with a low concentration of pathogens continue to present challenges for diagnosis and surveillance. We here report a simple and label-free approach via homobifunctional imidoesters (HIs) with a microfluidic platform (SLIM) to efficiently enrich and extract pathogens at low concentrations from clinical samples. The SLIM system consists of an assembled double microfluidic chip for streamlining large volume processing and HIs for capturing pathogens and isolating nucleic acids by both electrostatic and covalent interaction without a chaotropic detergent or bulky instruments. The SLIM system significantly increases the enrichment and extraction rate of pathogens (up to 80% at 10 CFU (colony forming unit) in a 1 mL volume within 50 min). We demonstrated its clinical utility in large sample volumes from 46 clinical specimens including environmental swabs, saliva, and blood plasma. The SLIM system showed higher sensitivity with these samples and could detect pathogens that were below the threshold of detection with other methods. Finally, by combining our SLIM approach with an isothermal optical sensor, pathogens could be detected at a very high sensitivity in blood plasma samples within 80 min via enrichment, extraction and detection steps. Our SLIM system thus provides a simple, reliable, cost-effective and ultrasensitive pathogen diagnosis platform for use with large volume clinical samples and would thus have significant utility for various infectious diseases.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SLIM system significantly increases the enrichment and extraction rate of pathogens. </LI> <LI> Demonstrated its clinical utility in large sample volumes from 46 clinical specimens. </LI> <LI> A simple, reliable, cost-effective and ultrasensitive pathogen diagnosis platform. </LI> </UL> </P>

Oral Pathogens and Their Antibiotics from Marine Organisms: A Systematic Review of New Drugs for Novel Drug Targets

Sehyeok Im,Jun Hyuck Lee,Youn-Soo Shim 한국치위생과학회 2024 치위생과학회지 Vol.24 No.2

Background: Recent studies have elucidated the quorum-sensing mechanisms, biofilm formation, inter-pathogen interactions, and genes related to oral pathogens. This review aims to explore the recent expansion of drug targets against oral pathogens and summarize the current research on novel antibiotic substances derived from marine organisms that target oral pathogens. Methods: A comprehensive literature review summarized the novel mechanisms pertaining to quorum-sensing signal transmission systems, biofilm formation, and metabolite exchange in oral pathogens. The amino acid sequences of the 16 proteins identified as potential drug targets were systematically classified and compared across various oral microorganisms. Results: Through a literature review, we identified nine studies researching quorum sensing signaling inhibitors targeting oral pathogens. A comparison of the amino acid sequences of 16 potential drug targets in oral microorganisms revealed significant differences between oral pathogens and beneficial oral symbiotic microorganisms. These findings imply that it is possible to design drugs that can bind more selectively to oral pathogens. Conclusion: By summarizing the results of recent research on the signaling mechanisms that cause pathogenicity, new drug targets against oral pathogens were proposed. Additionally, the current status of developing new antibiotics for oral pathogens using recently developed quorum sensing inhibitors and natural products derived from marine organisms was introduced. Consequently, marine natural products can be used to develop drugs targeting new proteins in oral pathogens.

급성 중이염의 원인 병원균과 Cefprozil 치료의 임상적 평가

강진한,김종현,박용수,최영철,노해일,양훈식,김규성,문연숙,홍영진,Kang, Jin-Han,Kim, Jong Hyun,Park, Yong-Soo,Choi, Young-Chul,Noh, Heil,Yang, Hoon Shik,Kim, Kyu Sung,Moon, Yeon Sook,Hong, Young Jin 대한소아청소년과학회 2003 Clinical and Experimental Pediatrics (CEP) Vol.46 No.5

목 적 : 국내에서 급성 중이염의 원인 규명에 관한 전향적 연구는 거의 없고, 합의된 진단 기준에 의한 임상 연구 또한 매우 미흡하다. 이에 저자들은 2000년 미국 CDC에서 합의된 급성 중이염의 임상적 진단 기준에 따른 급성 중이염 환아를 대상으로 원인 병원균의 규명과, 2세대 세팔로스포린계 항생제인 cefprozil을 투여하여 임상적 반응을 평가하고자 본 연구를 실시하게 되었다. 방 법 : 2001년 6월부터 2002년 6월까지 가톨릭대학교 성모자애병원과 성빈센트병원, 인하대학교 부속병원, 중앙대학교 성심병원의 응급실 및 소아과 또는 이비인후과 외래를 방문한 생후 6개월 이상 15세 이하 연령의 급성 중이염 환아 33명에게서 고막천자를 실시하여 원인균 규명을 시행하고, 1일 30 mg/kg 용량의 cefprozil을 10-12일간 투여하여 완치, 개선, 실패의 임상적 반응 기준으로 평가하였다. 동시에 분리된 균주에 대한 항균력 감수성 검사를 cefaclor, cefixim을 포함하여 실시하였다. 결 과 : 19명의 환아에서 원인 병원성 세균으로 S. pneumoniae(10례), H. influenzae(5례), S. aureus(2례), M. catarrhalis(1례), group A Streptococccus(1례)가 분리되었고, 14명에서는 세균이 분리되지 않았다. 원인 병원균이 분리된 환아에서 고막천공이 유의하게 많았고, 균이 분리되지 않은 환아에서 이통이 유의하게 많았다. 또한 병원균이 분리된 환아의 연령이 2세 미만이 대부분인 반면, 균분리가 되지 않은 환아들의 연령은 주로 2세 이상이었다. Cefrpozil의 임상반응 평가에서 병원균이 분리된 환아의 84.2%가 호전되었고, 병원균이 분리되지 않은 환아의 85.7%가 호전되었다. Cefprozil에 중등도 내성을 보인 S. pneumoniae가 분리된 환아의 경우에 임상적 호전이 있었던 반면 고도 내성을 보인 S. pneumoniae가 분리된 환아의 경우에는 치료실패를 보였다. Cefaclor, cefixime의 항균력 감수성 결과 분리된 S. pneumoniae에 1례만 감수성이 있고 모두 고도 내성을 보여 cefprozil의 경우와 뚜렷한 차이를 보였다. 결 론 : 새로운 급성 중이염 진단 기준에 의한 대상 환아 연구에서 급성 중이염의 원인이 60% 정도가 세균성 감염임을 확인하였고, 이 병원균 중 S. pneumoniae가 제일 주된 원인균 임을 확인하였다. 세균 감염에 의한 환아와 세균이 분리되지 않은 환아에서 임상적으로 세균성인 환아에서 중이 내 천공이 많았고, 무균성인 경우에는 이통 호소가 많았으며, 세균성인 경우의 환아 연령이 주로 2세 미만인 반면 무균성인 경우는 대부분 2세 이상인 차이점이 있었다. 급성 중이염 환아에 대한 cefprozil의 감수성 및 임상 평가, 이상반응에 대한 연구 결과는 외국의 경우와 유사함을 알 수 있었고, 중등도 내성 S. pneumoniae에는 좋은 반응을 보였으나 고도 내성 S. pneumoniae는 치료되지 않음을 확인하였다. Purpose : AOM is the most common bacterial URI in children. The bacteriology and antibiotic Tx of AOM in children has been studied in many countries. But, there is few study of causative pathogens and antibiotic Tx of AOM in our country. In this aspect, we performed prospective clinical study to confirm the causative pathogens and assess the clinical responses of cefprozil in AOM patients. Methods : Thirty three AOM patients enrolled in this study. Tympanocentesis for isolation of causative pathogens were performed before Tx of cefprozil. The study patients received cefprozil with dose of 15 mg/kg/bid.po/day for 10-12 days, and initially assessed the clinical response at 4-5 days after receiving cefprozil and finally at the end visit. In vitro susceptibility tests of cefprozil to isolated pathogens were done by disc diffusion method, and in vitro susceptibility tests of cefaclor and cefixime to isolated pathogens were simultaneously performed. Results : Bacterial pathogens[S. pneumoniae(10), H. influenzae(5), S. aureus(2), M. catarrhalis(1) and Group A stretococcus(1)] were isolated from 19 patients. Clinically, all patients had history of abrupt high fever except one. Tympanic perforation was dominant in pathogens isolated cases, and otalgia was significantly developed in non-pathogens isolated cases. The ages of pathogens isolated cases were usually below 2 years. Eighty four point nine percent of the patients including two cases with isolation of intermediate resistant S. pneumoniae were clinically improved. Antimicrobial in vitro activity to S. pneumoniae of cefprozil were superior than that of cefacor and cefixime. Conclusion : We confirm that bacteria has the causative role in about 60% cases, and S. pneumoniae is the most common pathogen. Clinically, there were some differences in symptoms, signs and ages between pathogens isolated and non-pathogens isolated cases. The clinical responses of cefprozil in our patients revealed similar outcomes to other countries. And we reconfirm that cefprozil may be clinically effective in cases of AOM due to intermediate resistant S. pneumoniae.

In vivo Pathogenicity Test of Oak Wilt Fungus (Raffaelea quercus-mongolicae) on Oriental Chestnut Oak (Quercus acutissima)

이수희,이진흥,서상태,이종규 강원대학교 산림과학연구소 2017 Journal of Forest Science Vol.33 No.4

Since the first report of the oak wilt disease at 2004 in Korea, the disease distributed over Korean peninsula and are still giving severe damages. The management of oak wilt disease in Korea has mainly focused on the control of insect vector, Platypus koryoensis. Neverthless the effective method for evaluating the pathogenicity of the pathogen, Raffaelea quercus-mongolicae (Rqm), and for screening chemical or biological agents with strong inhibitory activity against the pathogen, is absolutely necessary, an reliable method is not available so far. This study was conducted to develop the effective method for evaluating the pathogenicity of Rqm in oak trees. The culture suspensions of Rqm were artificially injected to the saplings of Quercus acutissima by using ChemJet tree injector. Three months after treatments, the treated saplings were cut and dipped into 1% fuchsin acid solution. There were significant differences in non-conductive area (%), discoloration area (%) and vertical discoloration length between the pathogen-injected and distilled water-injected control treatments. These results indicated that the pathogen is the causal agent for the dysfunction of water conductive tissue, which will finally result in wilt symptom. Re-isolation of the pathogen and PCR detection using specific primers for the pathogen also confirmed the presence of Rqm in the sapwood chips of the pathogen-injected saplings. These observations would be greatly applied to other related researches for evaluating the pathogenicity of tree wilt pathogens and biocontrol efficacy of the selected antagonistic microorganisms, in case that the wilt symptom is not easily shown by artificial inoculation of the causal agent.

Clinical Significance of Various Pathogens in Acute Exacerbations of COPD: Multi-center Study in Korea

( Hyun Woo Ji ),( Ji Ye Jung ),( Soojoung Yu ),( Hyun Woo Lee ),( Yun Su Sim ),( Hyewon Seo ),( Jeong-Woong Park ),( Kyung Hoon Min ),( Jae Ha Lee ),( Byung-Keun Kim ),( Myung Goo Lee ),( Yeon Mok Oh 대한결핵 및 호흡기학회 2021 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.129 No.0

Background One of the major causes of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is respiratory infection. In this study, we investigated types of bacteria and virus identified in AECOPD patients in Korea, and compared clinical difference according to different types of pathogen Methods We reviewed 1186 cases of AECOPD patients recruited at 28 hospitals in Korea from January 2015 to December 2019. Pathogen was identified by microbiological tests. We analyzed bacterial and viral identification rate, along with basic characteristics and clinical presentation of patients associated with the different types of pathogens, and risk factors for potentially drug-resistant (PDR) pathogen. Results The number of patients infected with bacteria, virus, and both bacteria and virus were 262 (22.1%), 265 (22.5%), and 129 (10.9%), respectively. The most common bacteria identified were Pseudomonas aeruginosa (9.8%), Mycoplasma pneumoniae (6.2%), and Streptococcus pneumoniae (5.0%). The most common virus identified Influenza A (10.4%), Rhinovirus (8.7%), and RSV (3.5%) Compared to patients without identified pathogens, patient with identified pathogens had a higher rate of systemic steroid use within six months (22.7% vs 16.9%; P=0.015), presented more cough and sputum (76.4% vs 68.9%; P=0.004, 78.9% vs 68.7%; P=0.015), and required longer period of systemic steroid during AECOPD (11.2days vs 4.4days; P=0.012). Past history of pulmonary tuberculosis (OR 1.66; P=0.046) and bronchiectasis (OR 1.99; P=0.032), and the history of triple inhaler use within six months (OR 2.04; P=0.005) have been confirmed as risk factors for the identification of PDR pathogen. In addition, hospital stay was longer (15.9days vs 12.4days; P=0.018) and ICU admission rate was high (15.9% vs 9.5%; P=0.030) when PDR pathogen was identified Conclusions The various types of pathogens caused AECOPD. In addition, risk factors for the identification of PDR pathogen were past history of pulmonary tuberculosis and bronchiectasis, and history of triple inhaler use.

Prevalence study of respiratory pathogens in Korean cats using real-time polymerase chain reaction

( Mi-jin Lee ),( Jin-ho Park ) 한국동물위생학회 2022 한국동물위생학회지 (KOJVS) Vol.45 No.3

Pathogens such as feline herpesvirus, feline calicivirus, Bordetella bronchiseptica, Chlamydia felis, Mycoplasma felis and Pasteurella multocida usually cause feline upper respiratory tract disease (URTD). Real-time PCR was used to analyze the detection and prevalence of the most common respiratory pathogens in cats with (n=69) and without respiratory signs (n=31). Pathogens were detected in 53 cats, divided into 37 (69.8%) with a single pathogen, 15 (28.3%) with two pathogens, and 1 (1.9%) with three pathogens. M. felis had the highest detection rate in 29 (42.0%) cats, P. multocida was detected in 18 (26.1%), FHV in 10 (14.5%), FCV in 7 (10.1%), B. bronchiseptica in 3 (4.3%), and C. felis in 2 (2.9%). M. felis was the most frequently detected pathogen in cats living outdoors without vaccination. Of the 37 cats infected with single pathogen, nasal discharge was observed in 13 (35.1%), ocular signs in 6 (16.2%), drooling in 5 (13.5%), dyspnea in 3 (8.1%), and asymptomatic in 10 (27.0%). In 51 outdoor and 49 indoor cats, pathogens were detected in 35 (68.6%) and 18 (36.7%) cats, respectively. Of the 29 cats infected with M. felis, 22 (75.9%) showed respiratory signs, and 7 (24.1%) were healthy. In the age of the 53 positive cats, 10 (18.9%) were under the age of 1 year, 26 (49.1%) were aged 1∼3 years, and 17 (32.1%) were aged 3 years or older. Although the number of cats in the study was small, the results can provide valuable data on the prevalence of URTD in Korean cats.