研究者業績

落合 由嗣

オチアイ ヨシツグ  (Yoshitsugu Ochiai)

基本情報

所属
日本獣医生命科学大学 獣医学部 獣医学科 教授
学位
博士(獣医学)(岐阜大学)

J-GLOBAL ID
200901022994569599
researchmap会員ID
5000017398

経歴

 1

論文

 31
  • Yoshitsugu Ochiai, Yuko Yoshikawa, Takashi Takano, Makoto Mori, Ryo Hondo, Mariko Mochizuki, Fukiko Ueda
    The Journal of veterinary medical science 82(6) 735-739 2020年4月9日  査読有り筆頭著者
    A Japanese resident bird, Phalacrocorax carbo hanedae (Japanese name: Kawa-u), was threatened with extinction due to deterioration of its habitat in the 1970s, but the population has since recovered thanks to environmental protection measures. This study analyzed the genetic diversity of 18 Kawa-u individuals living in the basins of the Abe and Warashina rivers in Shizuoka Prefecture, Japan. We obtained seven haplotypes of mitochondrial D-loop sequences and compared them with 49 European P. carbo D-loop haplotypes. We identified four new haplotypes but no clear genetic evidence distinguishing the Kawa-u as a distinct subspecies of P. carbo. Our results suggest the need for further surveillance of the P. carbo genetic lineage, regardless of the geographical distribution.
  • Yuko Yoshikawa, Kei Sugimoto, Yoshitsugu Ochiai, Norio Ohashi
    Microbiology and immunology 64(4) 270-279 2020年4月  査読有り
    Anaplasma phagocytophilum, an obligate intracellular bacterium that propagates within host granulocytes, is considered to modify the host intracellular environment for pathogenesis. However, the mechanism(s) underlying such host modifications remain unclear. Here, we aimed to investigate the relation between A. phagocytophilum and endoplasmic reticulum (ER) stress in THP-1 cells. A. phagocytophilum activated the three ER stress sensors: inositol-requiring enzyme-1 (IRE1), protein kinase RNA-like endoplasmic reticulum kinase (PERK), and activating transcription factor-6 (ATF6). IRE1 activation occurred immediately after host cell invasion by A. phagocytophilum; however, the activated IRE1-induced splicing of X-box-binding protein 1 was not promoted during A. phagocytophilum infection. This suppression was sustained even after the doxycycline-mediated elimination of intracellular A. phagocytophilum. IRE1 knockdown accelerated A. phagocytophilum-induced apoptosis and decreased intracellular A. phagocytophilum. These data suggest that A. phagocytophilum utilizes IRE1 activation to promote its own intracellular proliferation. Moreover, PERK and ATF6 partially mediated A. phagocytophilum-induced apoptosis by promoting the expression of CCAAT/enhancer-binding protein homologous protein, which induces the transcription of several proapoptotic genes. Thus, A. phagocytophilum possibly manipulates the host ER stress signals to facilitate intracellular proliferation and infection of surrounding cells before/after host cell apoptosis.
  • Yoshitsugu Ochiai, Yuko Yoshikawa, Mariko Mochizuki, Takashi Takano, Fukiko Ueda
    Food microbiology 86 103312-103312 2020年4月  査読有り筆頭著者責任著者
    Some Listeria monocytogenes strains are persistent in food processing environments, where this pathogen may be subjected to various stresses. This study aimed to elucidate the response of persistent strains of L. monocytogenes to low pH and H2O2 exposure. Almost all of the persistent strains examined were highly susceptible to low pH, whereas H2O2 susceptibility was comparable to that of control strains. Two persistent strains isolated from the same sample, however, exhibited lower susceptibility to low pH. These findings suggest an acid-susceptible phenotype predominates in the habitat, indicating that environmental conditions contribute to the establishment of persistence. Representative strains exhibiting acid-susceptible and less acid-susceptible phenotypes were further investigated regarding acid response characteristics. Less acid-susceptible strains exhibited increased survival in acidified brain heart infusion (BHI) broth compared with acidified phosphate-buffered saline (PBS). These strains also exhibited increased survival in acidified PBS containing glucose and glutamate, which are involved in acid response mechanisms, compared with acidified PBS alone. However, neither acidified BHI broth nor exogenous glucose and glutamate increased survival of acid-susceptible strains. An adaptive acid tolerance response of the acid-susceptible phenotype was observed, but this was limited compared with that of the less acid-susceptible phenotype.
  • Yuko Yoshikawa, Yoshitsugu Ochiai, Mariko Mochizuki, Takashi Takano, Ryo Hondo, Fukiko Ueda
    Japanese journal of infectious diseases 71(5) 373-377 2018年9月21日  査読有り
    The level of Listeria monocytogenes contamination of domestic retail meat in Tokyo, Japan, was assessed by comparison of isolates from 2004 to 2007 with those isolated before 2003. The overall prevalence of L. monocytogenes among these samples significantly diminished over time (1998-2003, 28.0%; 2004-2007, 17.6%) reflecting a significant decrease in the frequency of contamination of beef. Serotype 1/2a was isolated most frequently, reflecting a change in the predominant serotype in pork from 1/2c to 1/2a. We performed a simple genetic subtyping method based on 3 genes, iap, sigB, and actA, as well as traditional multilocus sequence typing to classify the allele types (ATs). No extensive variation among sequence types was detected. However, increased genetic diversity among the ATs of the 3 genes in the 2004-2007 isolates was evident. We identified AT 26 of the iap gene, which was not previously reported in Japanese isolates, and 6 ATs of the sigB gene, including 4 with nonsense mutations not currently registered in L. monocytogenes DNA databases. sigB is an evolutionally conserved gene that plays a role in the stress response. Our results indicate that the sigB gene may be relatively unstable among L. monocytogenes strains circulating in Japan.
  • Yoshitsugu Ochiai, Fumiya Yamada, Yuko Yoshikawa, Mariko Mochizuki, Takashi Takano, Ryo Hondo, Fukiko Ueda
    INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY 259 52-58 2017年10月  査読有り筆頭著者責任著者
    The food-borne pathogen Listeria monocytogenes is present persistently in food processing environments, where this bacterium is exposed to various stress factors, including oxidative stress. This study aimed to elucidate the temperature-dependent response of L. monocytogenes to H2O2 exposure and the phenotypic changes in colony formation by H2O2-treated bacteria. Survival curves indicated an increase in the resistance to H2O2 in L. monocytogenes as the temperature decreased during the stress exposure procedure. Transcriptional induction of genes with key roles in response to H2O2, including sigB and kat, was observed at 37 degrees C, but not at 20 degrees C, whereas other stress response genes were induced at both temperatures. Following H2O2 exposure, L. monocytogenes produced small colony phenotypes and the colony size decreased in a stress exposure duration-dependent manner. Resuscitated cells with no ability to form colonies in the absence of sodium pyruvate were also found. Our findings show the possibility that a sequential transition in the injury phenotype from small colony phenotype to resuscitated cells occurred during the course of exposure to H2O2. The higher H2O2 resistance at 20 degrees C than 37 degrees C suggests further investigation of the response to H2O2 exposure under the lower temperatures, including refrigeration temperature, which may contribute to elucidation of bacterial survival over extended time periods in food-processing environments.
  • Yuko Yoshikawa, Yoshitsugu Ochiai, Mariko Mochizuki, Osamu Fujita, Takashi Takano, Ryo Hondo, Fukiko Ueda
    JOURNAL OF VETERINARY MEDICAL SCIENCE 78(12) 1831-1839 2016年12月  査読有り
    Pulse field gel electrophoresis (PFGE) is widely used for listeriosis surveillance. Although this technique is effective for epidemiology, the data among laboratories are inconsistent. We previously reported a method for Listeria monocytogenes subtyping combined with sequence analysis of partial iap and whole genome restriction fragment length polymorphism (RFLP) using XbaI, ClaI (BanIII) and PstI. However, distinguishing subtypes was challenging, because the output comprised complicated fragment patterns. In this study, we aimed to establish a simple genotyping method that does not depend on visual observation, rather it focuses on multi-locus sequence typing (MLST) using three genes, iap, sigB and actA. Sixty-eight strains of L. monocytogenes including EGD-e as a reference strain were investigated to ensure consistency with previous data on the genetic characterization. All strains were grouped into 29 types by both analyses. Although there are some differences in classification, major clades included the same strains. Simpson's indices of diversity (SID) by MLST and iap-RFLP-based typing were 0.967 (95% confidence interval [CI]: 0.955/0.978) and 0.967 (95% CI: 0.955/0.979), respectively. The discriminatory power of both methods can be considered almost identical. Compared with the results of 38 selected strains, the strains within the MLST clusters in this study coincided with those obtained using PFGE. Thus, the MLST strategy could help differentiate among L. monocytogenes isolates during epidemiological studies.
  • T. Takano, Y. Okutomi, M. Mochizuki, Y. Ochiai, F. Yamada, M. Mori, F. Ueda
    ENVIRONMENTAL MONITORING AND ASSESSMENT 187(12) 2015年12月  査読有り
    Lead (Pb) is known to be highly poisonous, and the acute poisoning of Cd causes the abdominal pains, vomiting, and shock. The digestive and nervous symptom is observed in the chronic lead poisoning. It was also known that the defect in hemoglobin synthesis by Pb produce anemia. The release of Pb into the environment presents a source of exposure for wild animals. In this study, we examined the utility of a new Pb-monitoring index in mice administered Pb. A solution containing 0.02, 0.2, 2, or 4 ppm lead chloride (PbCl2) was administered intraperitoneally to mice, and the Pb contents of the kidney and liver were determined at designated time points. The mean Pb content of both organs increased depending on the administered Pb dosage. Although the results of control was near the detection limits, the administration of 4 ppm in 4 weeks resulted in Pb levels of 260 mg ppm/wet weight and 110 ppm wet weight in the kidney and liver, respectively. However, there were no significant relationships among administered dose, duration of Pb treatment, and liver or kidney Pb content. Then, values in all mice administered control or 0.02 mg Pb were located inside the ellipse, representing the confidence area of the new index, and values in all mice administered more than 2 mg Pb were located outside the ellipse. These results confirm that animals exposed to high concentrations of Pb would be detected by this new index.
  • Yoshitsugu Ochiai, Mariko Mochizuki, Fumiya Yamada, Takashi Takano, Ryo Hondo, Fukiko Ueda
    JAPANESE JOURNAL OF INFECTIOUS DISEASES 67(4) 258-263 2014年7月  査読有り筆頭著者責任著者
    A food-borne pathogen, Listeria monocytogenes serotype 4b, has been frequently isolated from patients with listeriosis, and numerous outbreaks of listeriosis are associated with this serotype. In the present study, we performed subtyping of L. monocytogenes serotype 4b strains on the basis of genetic analyses. Thirty-four isolates of serotype 4b were classified into 8 genotypes, namely genotypes 12, 15, 16, 17, 18, 23, 24, and 25, on the basis of the sequence for the partial iap gene. Genetic analyses revealed that genotype 16 and genotypes 24 and 25 belong to epidemic clone I (ECI) and ECII, respectively, which have been frequently associated with listeriosis outbreaks in the United States and Europe. The genotype isolated most frequently from retail meats in the Tokyo metropolitan area was genotype 12 (52%), followed by genotype 16 (29%), which belongs to ECI. We suggest that ECI is a common subtype of L. monocytogenes in retail meat in the area under investigation. On the other hand, ECII isolates were confirmed to be present in retail meat in Japan but were rare.
  • Yoshitsugu Ochiai, Fumiya Yamada, Mariko Mochizuki, Takashi Takano, Ryo Hondo, Fukiko Ueda
    JOURNAL OF FOOD PROTECTION 77(1) 133-140 2014年1月  査読有り筆頭著者責任著者
    Some Listeria monocyto genes strains, termed persistent strains, originate from the same processing plant and have the ability to survive and grow over extended periods of time at contamination sources. In order to evaluate biofilm formation by such persistent strains, we isolated the pathogen from chicken samples collected from the same retail shop in repeated visits over 6 months. Strains that were of serotype 1/2b and were assigned to the same genotype by multi-virulence-locus sequence typing analysis were isolated on repeated occasions from December 1997 to June 1998 and thus were defined as persistent strains. In the present study, biofilm formation by the persistent strains was evaluated using microplates at 30 and 37 degrees C. The biofilm-forming capability was measured after cells attaching to the microplate well were stained with crystal violet. Comparison of biofilm formation at 30 degrees C among the persistent strains showed that a significantly higher amount of the stain was obtained from the persistent strains isolated from December to March than from those isolated from April to June. However, no significant difference in biofilm formation at 30 degrees C was observed between persistent and nonpersistent groups of L. monocyto genes strains. In contrast, biofilm formation at 37 degrees C was consistent among the persistent strains, and they produced significantly more biofilm at 37 degrees C than did the nonpersistent strains. The persistent strains were also found to change their biofilm-forming ability in a temperature-dependent manner, which may suggest that the persistent strains alter their biofilm formation in response to changing environmental factors.
  • Mariko Mochizuki, Hanae Yamamoto, Risa Yamamura, Tomoko Suzuki, Yoshitsugu Ochiai, Jun Kobayashi, Koh Kawasumi, Toshiro Arai, Hiroshi Kajigaya, Fukiko Ueda
    JOURNAL OF VETERINARY MEDICAL SCIENCE 75(5) 667-670 2013年5月  査読有り
    Twenty nine oil-soaked birds were collected from around the Coast of Tsushima Island. The contents of eight elements in the livers and kidneys of the birds were investigated. Statistically higher concentrations of vanadium and thallium in the liver and of titanium in the kidney were found in the birds that were found dead compared with those that died after rescued. A significant correlation (r=0.695, P<0.01) was observed only for the molybdenum content between the kidneys and livers from the birds found dead. Although the controls of the eight elements of birds investigated in the present study remain unexplained, some of lower concentration in rescued birds can be blamed on a decrease in food intake of birds. The relation between oil contamination and concentration of elements need to be further explored.
  • Takashi Takano, Takeharu Kaneda, Masaki Kaneshige, Tomoko Tsutsumi, Yoshitsugu Ochiai, Kazumasa Shimizu, Ryo Hondo, Mariko Mochizuki, Fukiko Ueda
    BIOLOGICAL TRACE ELEMENT RESEARCH 151(2) 209-216 2013年2月  査読有り
    Titanium (Ti) is used in many fields, while cadmium (Cd) is known to cause the itai-itai disease. In the present study, possible interactions between titanium and cadmium were investigated. Aorta, taenia coli, and liver were removed from male guinea pigs. Muscle tension was measured using intact aorta and taenia coli and using beta-escin-permeabilized taenia coli in a physiological salt solution and a hyperpotassium solution containing Cd and/or Ti. Cellular Cd contents were determined using all tissues after washout with EDTA solution. Cadmium-induced relaxation in the hyperpotassium solution recovered significantly (P < 0.01) following Ti treatment in taenia coli, but not in the aorta. In beta-escin-permeabilized taenia coli, the percentage recoveries after Cd treatment and after Ti plus Cd treatment were 67.3 +/- 8.7 % (n = 4) and 87.7 +/- 3.8 % (n = 4), respectively, compared with Ca-induced control contraction. Cellular Cd contents in taenia coli decreased significantly following treatment with Ti 10(-4) M. Although similar results were obtained using the aorta and the liver, there were no significant differences between the control and Ti 10(-5) M. High concentrations of Ti may reduce cellular Cd content.
  • Yoshitsugu Ochiai, Fumiya Yamada, Otgonchimeg Batmunkh, Mariko Mochizuki, Takashi Takano, Ryo Hondo, Fukiko Ueda
    JOURNAL OF FOOD PROTECTION 73(9) 1688-1693 2010年9月  査読有り筆頭著者責任著者
    This study was conducted to decent-line the prevalence of Listen monocytogenes in retailed meats, comprising beef. chicken, and pork. in the Tokyo metropolitan area. A total of 379 samples of retailed meat were collected from 1998 to 2003, most of which were obtained by simultaneously purchasing the three classes of meat from a shop and then making another simultaneous purchase of meat from the same shop a few weeks later The prevalence of L monocytogenes was 28.0%, and the serotypes isolated were mainly 1/2a, 1/2b, 1/2c. and 4b Comparison of the prevalence of each scrotype among the classes of meat showed a predominant distribution of serotypes 1/2a. 1/2b, and 4b in chicken, while serotype 1/2c was dominant in pork. A total of nine cases considered to be due to persistence and/or cross-contamination were found Most of the strains involved in persistence and/or cioss-contamination were of serotypes 1/2c or 4b These results suggest that contamination in retailed meat in Japan is at almost the same level as in other countries and that chicken has the highest potential as a source of contamination and infection In addition, we suggest that the ecological niche of serotype 1/2c is distinct from those of 1/2a. 1/2b. and 4b. which may explain why human hosts have less opportunity to be exposed to serotype 1/2c and why there is a lower rate of isolation of this serotype from cases of human listeriosis.
  • Fukiko Ueda, Makoto Mori, Takashi Takano, Yoshitsugu Ochiai, Ryo Hondo, Mariko Mochizuki
    ENERGY, ENVIRONMENT, ECOSYSTEMS, DEVELOPMENT AND LANDSCAPE ARCHITECTURE 57-+ 2009年  査読有り
    The authors have recently developed a new cadmium (Cd) index (Cd standard regression line; CSRL) based on data from uncontaminated samples from many species. However, the samples from wildlife organs are often, and sometimes, we can not remove the blood in the tissues. The Cd remained in the blood may affect the content of the organ. Thus, preliminary work for an epidemiological study was performed upon a laboratory animal, the rat. After establishment of a constant level of Cd in rat serum, the Cd contents of various organs were compared following perfusion with 0.8% NaCl, with 1mM EDTA, or without any treatment. No significant differences were found among these organs, and the Cd levels in the organs were dependent on the infused Cd concentration. These results suggest that the Cd content in the blood did not affect the evaluation of the Cd content of the organs investigated. After the infusion of Cd, The ratio of liver and renal cortex was separated from the slope of the CSRL and was located at the upper part of the CSRL, while the data for the liver and renal medulla were located on the CSRL. From the results, we assumed that the assessment was correct, even if the content in the kidney cortex was considered to represent the Cd content of the whole kidney, when we could obtain the data only from the cortex. Furthermore, significant correlations were observed among the other organs, and strong multiple correlation was obtained among the Cd contents in liver, renal cortex, adrenal, renal medulla, pancreas, spleen and testis. These results suggest that contamination can be evaluated by measurement of the Cd content in these organs, even if samples of liver and/or kidney cannot be obtained.
  • Yoshitsugu Ochiai, Otgonchirneg Batmunkh, Kunitoshi Ogasawara, Mariko Mochizuki, Ryo Hondo, Fukiko Ueda
    INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY 127(1-2) 12-17 2008年9月  査読有り筆頭著者責任著者
    Phylogenetic analyses were carried out on a total of 118 Listeria monocytogenes isolates from foods or food processing environments, and 7 isolates from listeriosis patients in Japan to evaluate the genetic variation in the pathogen in this country. Isolates of serotypes 1/2a, 1/2b and 4b were mainly examined to assess the risk of exposure of humans to L. monocytogenes from foods in Japan. The nucleotide sequences of the part of the iap gene that contains the region encoding the threonine-asparagine repeat units were determined in order to construct phylogenetic trees of the isolates investigated. A phylogram showed high genetic diversity among lineage 2 isolates. while the lineage I isolates showed clonal characteristics. The results of the genetic analyses suggested the presence of rare putative lineage 3 isolates and epidemic clone I (ECI) isolates in foods in Japan. The results showed that ECI was also isolated from listeriosis patients. The genetic variation in L. monocytogenes in Japan reported here suggests the necessity of monitoring the pathogen in foods and environments in addition to surveillance of listeriosis patients. (C) 2008 Elsevier B.V. All rights reserved.
  • Akikazu Fujima, Yoshitsugu Ochiai, Aya Saito, Yuki Omori, Atsuya Noda, Yukumasa Kazuyama, Hiroshi Shoji, Kiyoshi Tanabayashi, Fukiko Ueda, Yasuhiro Yoshikawa, Ryo Hondo
    JOURNAL OF CLINICAL MICROBIOLOGY 46(1) 56-61 2008年1月  査読有り責任著者
    The antigenic cross-reactive characteristics of herpes B virus and herpes simplex virus (HSV) type 1 (HSV-1) and HSV-2 are responsible for false-positive diagnoses by serological assays in humans and macaques. In the present study, we developed a fluorometric indirect enzyme-linked immunosorbent assay (ELISA) with recombinant herpes B virus glycoprotein D (gD) and HSV-1 and HSV-2 gG (gG-1 and gG-2, respectively) to discriminate between the three primate herpesvirus infections. The secreted form of gD, gDdTM, was used to detect antibody to herpes B virus gD. Sera positive for herpes B virus, HSV-1, and HSV-2 showed specific reactions to gD, gG-1, and gG-2, respectively. Sera collected from humans and rhesus macaques were investigated for the presence of antibodies to the recombinant proteins of the three herpesviruses. The results suggested that the approach is able to discriminate between herpes B virus and HSV infections. The ELISA was also found to be able to detect infections with multiple primate herpesviruses and may have the potential to identify a subsequent infection in individuals that have already been infected with another herpesvirus. In addition, we found evidence of a greater cross-reactivity of herpes B virus with HSV-1 than with HSV-2. It is suggested that the ELISA with the recombinant antigens is useful not only for the serodiagnosis of primate herpesvirus infections but also for elucidation of the seroprevalence of herpesviruses in humans and primates.
  • C. Oya, Y. Ochiai, Y. Taniuchi, T. Takano, A. Fujima, F. Ueda, R. Hondo, Y. Yoshikawa
    LABORATORY ANIMALS 42(1) 99-103 2008年1月  査読有り
    Herpes B virus infection is almost asymptomatic in macaques (Macaca spp.), which are the natural hosts of this pathogen, but is the cause of high mortality in humans. Reactivation of the latent virus in the trigeminal ganglia (TG) results in the shedding of infectious particles into the oral mucosal membrane. Saliva contaminated with the reactivated virus from the ganglia of the natural host is considered to be important for viral transmission to humans and other monkeys. In the present study, we investigated the prevalence of the herpes B virus genome in the left and right TG of seropositive asymptomatic cynomolgus macaques. The latent virus genome was detected using a polymerase chain reaction and microplate hybridization assay. We found that the virus DNA was present in one or both TG of 12 of the 30 macaques (40%) tested, with the virus being detected from both TG in five of the 12 macaques and from a single TG in the remaining seven.
  • Tomoko Takahashi, Yoshitsugu Ochiai, Hiroki Matsudate, Kazuhiro Hasegawa, Toshio Segawa, Masafumi Fukuda, Ryo Hondo, Fukiko Ueda
    JOURNAL OF VETERINARY MEDICAL SCIENCE 69(10) 1077-1079 2007年10月  査読有り責任著者
    We attempted to isolate Listeria monocytogenes from skin, contents of large intestines and carcasses of cattle introduced to a slaughterhouse in order to identify source of contamination for this pathogen. Sixty skin samples, 60 samples of the contents of large intestines and 30 carcass samples were colleted in June, August and November 2003 for use in this study. Listeria spp. and L. monocytogenes were isolated from 30 (50%) and 3 (5%) of the cattle skin samples, respectively. However, no Listeria spp., including L. monocytogenes, were isolated from intestinal contents or carcasses. Seven isolates were obtained, of which five and two strains were serotypes 1/2a and 1/2b, respectively. Genetic analysis suggested that there was persistent inhabitation of the pathogen around the area investigated in this study.
  • A. Desiree LaBeaud, Yoshitsugu Ochiai, C. J. Peters, Eric M. Muchiri, Charles H. King
    AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE 76(5) 795-800 2007年5月  査読有り
    Rift Valley fever virus (RVFV) is an emerging pathogen that maintains high biodefense priority based on its threat to livestock, its ability to cause human hemorrhagic fever, and its potential for aerosol spread. To define the range of human transmission during inter-epidemic and epidemic periods in Kenya, we tested archived sera from defined populations (N = 1,263) for anti-RVFV IgG by ELISA and plaque reduction neutralization testing. RVFV seroprevalence was 10.8% overall and varied significantly by location, sex, and age. In NW Kenya, high seroprevalence among those born before 1980 indicates that an undetected epidemic may have occurred then. Seroconversion documented in highland areas suggests previously unsuspected inter-epidemic transmission. RVFV seroprevalence is strikingly high in certain Kenyan areas, suggesting endemic transmission patterns that may preclude accurate estimation of regional acute outbreak incidence. The extent of both epidemic and inter-epidemic RVFV transmission in Kenya is greater than previously documented.
  • F Yamada, F Ueda, Y Ochiai, M Mochizuki, H Shoji, K Ogawa-Goto, T Sata, K Ogasawara, A Fujima, R Hondo
    JOURNAL OF MICROBIOLOGICAL METHODS 66(1) 96-103 2006年7月  査読有り
    The invasion ability of Listeria monocytogenes into cultured cells has been used to evaluate its pathogenicity. In this study, invasive ability was investigated using Vero and Caco-2 cell lines. The form of invasion showed no morphological differences between both cell lines inoculated with L. monocytogenes L89-H2 or L96-23C1 strains when double fluorescence stained with rhodamine and FITC or with Giemsa staining. Recovery count and recovery rate of L. monocytogenes from Vero cells was related to the number of inoculated bacteria (2 x 10(5) to 2 X 10(7)/ml) in a bell-shape pattern, though the relationship was unclear in Caco-2 cells. Recovery rate of L. monocytogenes was higher in Vero cells than Caco-2 cells at a multiplicity of infection (MOI) 10, though the rates in both cells showed different stable stages over a considerably wide range of MOI. The recovery rate of all five L. monocytogenes strains from listeriosis patients was 15% at MOI 10 from infected Vero cells, while meat-derived strains showed variable rates regardless of the serovar. These results suggest that the Vero cell line is suitable for an invasion assay and that a recovery rate of 15% may be the critical limit for the expression of pathogenicity in the host. (c) 2005 Elsevier B.V. All rights reserved.
  • F Ueda, R Anahara, F Yamada, M Mochizuki, Y Ochiai, R Hondo
    INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY 105(3) 455-462 2005年12月  査読有り
    Discrimination was attempted on 14 Listeria monocytogenes strains isolated from commercially available Japanese pork and chicken. Examination of the isolates was performed by restriction fragment length polymorphism (RFLP) analysis of the chromosomal DNA and amplified products and comparison of the nucleotide sequences of the amplified products. A polymorphism region containing the repeated sequences in the iap gene was amplified by the polymerase chain reaction (PCR). The genetic analyses could discriminate the 14 isolates in combination with traditional serotyping, and some strains isolated from different meats were confirmed to have a genetically close relationship. Genetic analyses used in the present study would be useful for the elucidation of the pathogen tracks from contaminated sources to humans and of the ecological niche in the food environment. (C) 2005 Elsevier B.V. All rights reserved.
  • Y Ochiai, C Takada, M Hosaka
    APPLIED AND ENVIRONMENTAL MICROBIOLOGY 71(2) 898-903 2005年2月  査読有り筆頭著者責任著者
    Cryptosporidium parvum and C. hominis have been the cause of large and serious outbreaks of waterborne cryptosporidiosis. A specific and sensitive recovery-detection method is required for control of this pathogen in drinking water. In the present study, nested PCR-restriction fragment length polymorphism (RFLP), which targets the divergent Cpgp40/15 gene, was developed. This nested PCR detected only the gene derived from C. parvum and C. hominis strains, and RFLP was able to discriminate between the PCR products from C. parvum and C. hominis. To evaluate the sensitivity of nested PCR, C. parvum oocysts inoculated in water samples of two different turbidities were recovered by immunomagnetic separation (IMS) and detected by nested PCR and fluorescent antibody assay (FA). Genetic detection by nested PCR and oocyst number confirmed by FA were compared, and the results suggested that detection by nested PCR depends on the confirmed oocyst number and that nested PCR in combination with IMS has the ability to detect a single oocyst in a water sample. We applied an agitation procedure with river water solids to which oocysts were added to evaluate the recovery and detection by the procedure in environmental samples and found some decrease in the rate of detection by IMS.
  • C Oya, Y Ochiai, Y Taniuchi, T Takano, F Ueda, Y Yoshikawa, R Hondo
    JOURNAL OF CLINICAL MICROBIOLOGY 42(5) 1869-1874 2004年5月  査読有り
    Herpes B virus DNA was specifically amplified by PCR, targeting the regions that did not cross-react with herpes simplex virus (HSV). The amplified products, which were shown to be highly genetic polymorphisms among herpes B virus isolates, were identified by microplate hybridization with probes generated by PCR. The products immobilized in microplate wells were hybridized with the biotin-labeled probes derived from the SMHV strain of herpes B virus. The amplified products derived from the SMHV and E2490 strains of herpes B virus were identified by microplate hybridization. PCR products amplified from the trigeminal ganglia of seropositive cynomolgus macaques were identified as herpes B virus DNA. The utility of the PCR-microplate hybridization assay for genetic detection and identification of the polymorphic region of herpes B virus was determined.
  • Y Ochiai, H Fukushi, C Yan, T Yamaguchi, K Hirai
    JOURNAL OF VETERINARY MEDICAL SCIENCE 62(9) 941-945 2000年9月  査読有り筆頭著者
    The nucleotide sequences of the gene encoding chlamydial heat shock protein 60 (cHSP60) of 7 Chlamydia psittaci strains were determined. Comparison of sequences of the cHSP60 gene among chlamydiae showed high identities of the nucleotide sequences by 81.0% or greater and of the deduced amino acid sequences by 92.2% or greater. Comparison of the amino acid sequences between chlamydia and the other bacterial HSP60s resulted in the finding of three highly conserved regions, suggesting that these regions play a role in some function. In addition, 26- or 27-functional residues in the Escherichia coli GroEL out of the 28-residues are conserved in the amino acid sequences of the cHSP60. The data suggest that the function of the cHSP60 may be the same as that of the E. coli GroEL.
  • Y Ochiai, H Fukushi, Y Cai, T Yamaguchi, K Hirai
    MICROBIOLOGY AND IMMUNOLOGY 43(5) 419-424 1999年  査読有り筆頭著者
    A highly conserved 40-nucleotide sequence was identified. Two completely conserved sequences, TAGATT and TAAACT, separated by 17 nucleotides resemble the consensus sequence recognized by the Escherichia coli major sigma factor and sequence found in other chlamydial promoters. In addition, the adenine-rich sequence present in many chlamydial promoters was also conserved upstream of the putative -35 element. These findings suggest that the conserved sequence may play a role in the regulatory function at the transcriptional level, Multiple ATG codons were found at the 5'-terminal region of the chlamydial sigA ORFs except for Chlamydia pneumoniae, although the putative Shine-Dargarno sequence was absent.
  • 石原 加奈子, 松舘 宏樹, 安田 恵子, 小川 基彦, 水谷 美穂, 堀田 明豊, 落合 由嗣, 山口 剛士, 福士 秀人, 平井 克哉
    日本獣医学会学術集会講演要旨集 126回 122-122 1998年8月  査読有り
  • Pudjiatmoko, Fukushi Hideto, Ochiai Yoshitsugu, YAMAGUCHI Tsuyoshi, HIRAI Katsuya
    Microbiology and Immunology Vol. 42 pp. 61-63(1) 61-63 1998年1月  査読有り
    The in vitro susceptibility of Chlamydia pecorum to two macrolides (clarithromycin and erythromycin), two tetracyclines (doxycycline and minocycline), two quinolones (ofloxacin and ciprofloxacin) and one β-lactam (ampicillin) was determined. The MICs were 0.004 to 0.008μg/ml for clarithromycin, 0.008 to 0.031μg/ml for doxycycline and minocycline, 0.063 to 0.125μg/ml for erythromycin, 0.25 to 0.5μg/ml for ofloxacin and 0.25 to 1.0μg/ml for ciprofloxacin. The MIC for ampicillin was greater than 1, 024μg/ml. The results show clarithromycin and doxycycline are the two most effective drugs against C. pecorum.
  • Pudjiatmoko, H Fukushi, Y Ochiai, T Yamaguchi, K Hirai
    INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY 47(2) 425-431 1997年4月  査読有り
    The phylogenetic relationships among Chlamydia spp. were investigated by comparing 16S rRNA gene sequences. In this analysis we used 14 strains of Chlamydia psittaci, including seven feline isolates, two avian isolates, two human isolates, one bovine isolate, one ovine isolate, and one guinea pig isolate; five strains of Chlamydia pecorum, including three bovine isolates, one ovine isolate, and one koala isolate; and nine strains of Chlamydia trachomatis, including six human isolates, two swine isolates, and one mouse isolate. A phylogenetic analysis of the 16S rRNA gene sequences of these organisms and seven previously published sequences revealed eight genetic groups which formed two clusters. The first cluster was composed of C. pecorum, Chlamydia pneumoniae, and C. psittaci and included three genetic groups (one group containing avian: human, and ovine strains, one group containing feline strains, and one group containing guinea pig strains). The second cluster was composed of C. trachomatis and also included three genetic groups (one group containing human strains, one group containing swine isolates, and one group containing rodent strains). The strains in each genetic group exhibited similar genetic distances. The results of the phylogenetic analysis agreed with the results of previous genomic DNA, ompA gene allele, and biotyping studies. Therefore, the genetic groups based on genetic distances may be considered a criterion for species identification.
  • Pudjiatmoko, H Fukushi, Y Ochiai, T Yamaguchi, K Hirai
    VETERINARY MICROBIOLOGY 54(1) 73-83 1997年1月  査読有り
    DNA samples from C. psittaci including 6 strains of feline origin, 10 strains of avian origin, 1 strain of ovine origin and 1 strain of guinea pig origin were amplified each with three 10-nucleotide (nt) primers and four > 18-nt primers. Amplified products were separated by polyacrylamide gel electrophoresis. Eight patterns were recognized by random amplification of polymorphic DNA (RAPD) fingerprinting of C. psittaci: 2 patterns of feline origin, 5 patterns of avian origin acid 1 pattern of guinea pig origin. DNA of feline or guinea pig origin was clearly distinguished from the other strains of C. psittaci by RAPD analysis, as shown by the absence of any common fragments in electrophoresis. The RAPD analysis indicated at least 2 types of feline C. psittaci. The RAPD typing is suggested as a convenient tool for molecular epidemiology of chlamydial infection.
  • H Fukushi, T Tomita, A Taniguchi, Y Ochiai, R Kirisawa, T Matsumura, T Yanai, T Masegi, T Yamaguchi, K Hirai
    VIROLOGY 227(1) 34-44 1997年1月  査読有り
    A herpesvirus was isolated from Thomson's gazelle (Gazella thomsoni) kept al a zoological garden in Japan during an outbreak of epizootic acute encephalitis. The virus, gazelle herpesvirus 1 (GHV-1), was serologically related to equine herpesvirus 1 (EHV-1). However, DNA fingerprints of GHV-1 were different from those of EHV-l and other equine herpesviruses. Southern hybridization with probes of cloned BamHI fragments derived from U-L and U-s segments of EHV-I revealed differences in the DNA restriction profiles throughout the entire genome. Nucleotide sequences were determined for a conserved region of an essential envelope glycoprotein B (gB) gene and a type-specific glycoprotein G (gG) homologue gene. The predicted amino acid sequence of GHV-1 gB showed 97, 92, 61, and 57% identity to EHV-I, EHV-4, feline herpesvirus, and pseudorabies virus, respectively, indicating that GHV-1 was closer to EHV-1 than any other herpesvirus. The GHV-1 gG gene showed 93.2, 92.3, and 53% identity to EHV-I, EHV-8, and EHV-4 gGs, respectively. GHV-1 was virulent to suckling mice of the ICR strain by intracerebral inoculation and was Virulent to 4-week-old BALB/c mice by intranasal inoculation, causing neurological symptoms and death. We conclude that GHV-1 is a new type of equine herpesvirus with strong neurotropism. (C) 1997 Academic Press
  • H To, N Kako, GQ Zhang, H Otsuka, M Ogawa, O Ochiai, SV Nguyen, M Akiyama, T Yamaguchi, H Fukushi, N Nagaoka, K Amano, K Hirai
    JOURNAL OF CLINICAL MICROBIOLOGY 34(3) 647-651 1996年3月  査読有り
    The prevalence of Q fever pneumonia among children with atypical pneumonia from whom only an acute-phase serum sample was available was traced by using an indirect immunofluorescence (IF) test, nested PCR, and isolation. Twenty (34.5%) of 58 sera were found to have both polyvalent and immunoglobulin M antibodies to the phase II antigen of Coxiella burnettii by the IF test, Q fever pneumonia wets present in 23 (39.7%) of 58 patients as determined by both the nested PCR and isolation and in 20 patients as determined by the IF test, The sensitivities for nested PCR and isolation were 100%, and that for the IF test was 87%, Our results indicate that nested PCR was faster and more sensitive than isolation and the IF test in the diagnosis of acute Q fever when a single acute-phase serum was available. These findings suggest that C. burnetii is an important cause of atypical pneumonia in children in Japan.
  • Pudjiatmoko, H Fukushi, Y Ochiai, T Yamaguchi, K Hirai
    MICROBIOLOGY AND IMMUNOLOGY 40(10) 755-759 1996年  査読有り
    The prevalence of anti-chlamydia antibodies was examined in 232 cat sera collected in 1985 and from 1993 to 1995 from laboratories and veterinary hospitals located in 11 prefectures of Japan. The antibodies were determined by an indirect microimmunofluorescence test using six strains of feline Chlamydia: one strain each of avian- and guinea pig-derived C. psittaci and one strain each of C. pecorum, C. pneumoniae and C. trachomatis. Positive rates of IgG antibodies to chlamydiae were 34.4% in 1985 and 16.5-21.4% from 1993 to 1995. Positive rates of IgM antibodies to chlamydiae were 8.2% in 1985 and 6.6-14.3% from 1993 to 1995. Variations in antibody reactivity to the different feline strains were observed. The results suggest the wide prevalence of chlamydial infection in cats in Japan, and antigenic diversity in the feline strains of C. psittaci.

MISC

 4
  • Mariko Mochizuki, Mayumi Shiozawa, Makoto Mori, Hiroshi Kajigaya, Shin ichi Hayama, Yoshitsugu Ochiai, Ryo Hondo, Fukiko Ueda
    Energy, Environment and Economics Research Compendium 197-205 2013年2月1日  
    © 2013 by Nova Science Publishers, Inc. All rights reserved. The cadmium (Cd) content in the kidneys and livers of wild birds was compared after classification based on the type of migration and the breeding area. A high Cd content was detected in the organs of Pacific loons breeding in North America, but these birds were thought to have been affected by oil contamination. The Cd content of organs from spotbill ducks, which are birds that are resident in Japan, tended to be higher than those of other birds that breed outside Japan. The rank order of the mean Cd level with respect to location was "only in Eurasia" < "both Eurasia and North America" < "only in North America". The type of migration did not affect the Cd content of the organs. We also investigated the relationship between the Cd content of the organs and the Japanese environmental concentration of Cd. The Cd contents of organs from birds collected on the shore of the Japan Sea were generally higher than those of the birds collected near the Pacific Ocean. These results seem to be related to the concentration of Cd in the soil. From these results, we showed that the differences in the Cd content in organs from Japanese wild birds were related to their breeding area but not to the type of migration. Further, the area from which the wild birds were collected was strongly related to the Cd content of the organs. This demonstrated the relationship between the environmental and soil conditions in Japan and the level of pollution of the birds studied.
  • Mariko Mochizuki, Mayumi Shiozawa, Makoto Mori, Hiroshi Kajigaya, Shin Ichi Hayama, Yoshitsugu Ochiai, Ryo Hondo, Fukiko Ueda
    Advances in Environmental Research. Volume 4 269-278 2010年1月1日  
    © 2010 by Nova Science Publishers, Inc. All rights reserved. The cadmium (Cd) content in the kidneys and livers of wild birds was compared after classification based on the type of migration and the breeding area. A high Cd content was detected in the organs of Pacific loons breeding in North America, but these birds were thought to have been affected by oil contamination. The Cd content of organs from spotbill ducks, which are birds that are resident in Japan, tended to be higher than those of other birds that breed outside Japan. The rank order of the mean Cd level with respect to location was "only in Eurasia" < "both Eurasia and North America" < "only in North America". The type of migration did not affect the Cd content of the organs. We also investigated the relationship between the Cd content of the organs and the Japanese environmental concentration of Cd. The Cd contents of organs from birds collected on the shore of the Japan Sea were generally higher than those of the birds collected near the Pacific Ocean. These results seem to be related to the concentration of Cd in the soil. From these results, we showed that the differences in the Cd content in organs from Japanese wild birds were related to their breeding area but not to the type of migration. Further, the area from which the wild birds were collected was strongly related to the Cd content of the organs. This demonstrated the relationship between the environmental and soil conditions in Japan and the level of pollution of the birds studied.
  • 保坂 三継, 落合 由嗣, 矢野 一好
    用水と廃水 Vol. 44 pp. 295-303(4) 295-303 2002年  
  • 保坂 三継, 落合 由嗣, 矢野 一好
    東京都立衛生研究所研究年報 Vol. 52 pp. 254-259(52) 254-259 2001年  

講演・口頭発表等

 2

担当経験のある科目(授業)

 7

共同研究・競争的資金等の研究課題

 5