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Makoto Miyaji

Publications and source records attributed to Makoto Miyaji.

At least 19 recordsLinked to original sources
PubMed2006

Reexamination of Coccidioides spp. reserved in the Research Center for Pathogenic Fungi and Microbial Toxicoses, Chiba University, based on a multiple gene analysis.

The Research Center for Pathogenic Fungi and Microbial Toxicoses, Chiba University is the only organization in Japan to possess a series isolates of Coccidioides spp., which are the most virulent pathogenic fungi and which are treated as biosafety level 3 microorganisms. Recently, the genus Coccidioides has been classified into two species, C. immitis and C. posadasii, based on their endemic areas and genotyping; the former species is endemic to the state of California, and the latter is endemic to other parts of North and South America. We reevaluated 19 isolates of Coccidioides immitis stored in our center using a multiple gene analysis. Five isolates were identified as C. immitis and 14 as C. posadasii. Their sequence information in GenBank will help to identify the two genospecies of Coccidioides spp.

Coccidioides↗
PubMed2005

Rapid identification of Ochroconis gallopava by a loop-mediated isothermal amplification (LAMP) method.

Ochroconis gallopava is a species of dematiaceous fungi recognized as a causative agent of zoonotic and emerging fungal infections. It affects the central nervous system and respiratory tracts of humans, birds and cats. We designed O. gallopava species-specific primer sets to aid in its identification by a loop-mediated isothermal amplification (LAMP) method based on the D1/D2 domain of the LSU rDNA sequence. The LAMP method successfully detected the gene from both fungal DNA and experimentally infected brains and spleens of mice and will be helpful in the diagnosis of O. gallopava infection.

Animals↗
PubMed2004

Detection of gp43 of Paracoccidioides brasiliensis by the loop-mediated isothermal amplification (LAMP) method.

Paracoccidioidomycosis is a deep mycosis caused by the thermo-dependent dimorphic fungus Paracoccidioides brasiliensis and is prevalent in Latin American countries. We detected the species specific gp43 gene of P. brasiliensis by loop-mediated isothermal amplification (LAMP) in 22 clinical and seven armadillo-derived isolates. The amplified DNA appeared as a ladder with a specific banding pattern. The advantage of the LAMP method is speed; only 3 h were necessary for identification of the organism and diagnosis of the disease. We were also able to obtain positive results from DNA extracted from a paraffin-embedded tissue sample of paracoccidioidomycosis, suggesting that this method may achieve clinical application in the near future.

Animals↗
PubMed2004

New decalin derivatives, eujavanoic acids A and B, from Eupenicillium javanicum.

Two new decalin derivatives, eujavanoic acids A (1) and B (2), were isolated from Eupenicillium javanicum, along with several compactin derivatives. The structures of 1 and 2 were determined by spectroscopic methods and modified Mosher's method. The side chain (2-methylbutanoyloxy) and acid functionalities of compactin derivatives were necessary to show the antifungal activity.

Antifungal Agents↗
PubMed2004

Effect of aeration on gliotoxin production by Aspergillus fumigatus in its culture filtrate.

Gliotoxin, one of the mycotoxins produced by Aspergillus fumigatus, has various, potent bioactivities. However, it has not been considered to be a toxic (or virulence) factor because of its slow production. The aim of the present study was to investigate the effects of aeration on the cytotoxicity of A. fumigatus culture filtrate, and to determine the optimal condition for the rapid production of gliotoxin from this fungus. Fungal culture filtrates were made in three different containers under various conditions of aeration and O2 concentration. These filtrates were compared in terms of their cytotoxicity on murine macrophages and analyzed by gas chromatography. The culture filtrate showed high cytotoxicity when it was made under highly aerated conditions, but it was significantly less cytotoxic when prepared under non-aerated conditions. The cytotoxic activity became evident within 15 h of culture at 20% O2, when the fungus had already started producing gliotoxin. The culture filtrates also contained some other as yet unidentified substances that might also to some extent contribute to the cytotoxicity. In light of these results, the authors propose that a highly aerated condition is responsible for the rapid production of gliotoxin, and that gliotoxin might play an important role in the respiratory infection by A. fumigatus, with other toxic substances acting additively or synergistically.

Animals↗
PubMed2004

Effect of aeration on gliotoxin production by Aspergillus fumigatus in its culture filtrate.

Gliotoxin, one of the mycotoxins produced by Aspergillus fumigatus, has various, potent bioactivities. However, it has not been considered to be a toxic (or virulence) factor because of its slow production. The aim of the present study was to investigate the effects of aeration on the cytotoxicity of A. fumigatus culture filtrate, and to determine the optimal condition for the rapid production of gliotoxin from this fungus. Fungal culture filtrates were made in three different containers under various conditions of aeration and O2 concentration. These filtrates were compared in terms of their cytotoxicity on murine macrophages and analyzed by gas chromatography. The culture filtrate showed high cytotoxicity when it was made under highly aerated conditions, but it was significantly less cytotoxic when prepared under non-aerated conditions. The cytotoxic activity became evident within 15 h of culture at 20% O2, when the fungus had already started producing gliotoxin. The culture filtrates also contained some other as yet unidentified substances that might also to some extent contribute to the cytotoxicity. In light of these results, the authors propose that a highly aerated condition is responsible for the rapid production of gliotoxin, and that gliotoxin might play an important role in the respiratory infection by A. fumigatus, with other toxic substances acting additively or synergistically.

Aerobiosis↗
PubMed2003

Diagnosis of histoplasmosis by detection of the internal transcribed spacer region of fungal rRNA gene from a paraffin-embedded skin sample from a dog in Japan.

The lesions of histoplasmosis in dogs in Japan differ from those in dogs in North America. Affected dogs in Japan have had multiple granulomatous or ulcerated foci in skin or gingiva and have not had pulmonary or gastrointestinal lesions. The present report introduces a polymerase chain reaction (PCR) diagnosis of canine histoplasmosis and the characteristic of disease in Japan. The surgically removed skin ulcerate samples from a 5-years-old female Shiba-inu native to Japan without traveling out of the country were evaluated. Tissue samples had many yeast-like organisms in the macrophages. DNA was extracted from paraffin-embedded tissue samples. A nested PCR technique was applied. The detected sequence of the internal transcribed spacer of ribosomal RNA gene had 99.7% in homology with Ajellomyces capsulatus (the teleomorph of Histoplasma capsulatum). Clinical manifestations, historical background of equine epizootic lymphangitis in Japan, and a human autochthonous case of histoplasmosis farciminosi indicated that this dog might have been infected with H. capsulatum var. farciminosum as a heteroecism.

Animals↗
PubMed2003

The trend of imported mycoses in Japan.

Pathogenic fungi that are non-native in Japan are highly virulent and present a significant health hazard to persons in the environment into which they are introduced. Little is known, however, about the precise trend of infection by imported mycoses in Japan. To clarify this issue, all available cases were collected through a search of MEDLINE and Japana Centra Revuo Medicine and analyzed. Also included in this analysis were cases not reported in the literature for which the authors provided identification of the fungi, diagnosis, or treatment. The analysis revealed that, for three diseases, the number of imported mycoses cases in Japan is much higher than previously reported: 31 cases of coccidioidomycosis, 34 cases of histoplasmosis, and 17 cases of paracoccidioidomycosis. Additionally, one case of penicilliosis marneffei was found. The most rapid increase in the incidence of these mycoses occurred from 1991 to 1995. Analysis of the patients' profiles provided the following information: (1) coccidioidomycosis infection in Japan is increasing very rapidly, (2) Japan might be an endemic area of histoplasmosis infection, (3) histoplasmosis is a potentially fatal disease; and (4) reliable serodiagnostic methods have been used only infrequently. Because of the increase of international travel and immigration, the incidence of imported mycoses in Japan is expected to continue rising, and mycoses that have never been reported in Japan, such as blastomycosis, might also be encountered in the near future. To cope with this newly emerging health problem to residents of Japan, the Japanese medical system must train its members to identify and treat mycoses.

Adolescent↗
PubMed2003

Immunosuppressive substances in Aspergillus fumigatus culture filtrate.

Invasive aspergillosis has become a serious problem in clinical practice, but the actual factor that confers virulence on the fungus has not been thoroughly elucidated. To identify and isolate the immunosuppressive substances produced by the fungus, the bioactivity of culture filtrates was assessed, and analyses of the culture filtrates were carried out. Culture filtrates from different strains of Aspergillus fumigatus were assessed for their effect on human polymorphonuclear leukocytes and murine macrophages. To assess their activities in vivo, their effect on the survival of mice infected by the fungus was also studied. Subsequently, the composition of the culture filtrates was analyzed by gas chromatography-mass spectrometry. The analyses revealed that the culture filtrates contained gliotoxin at concentrations of 3 to 4 microgram/ml, and some other unidentified compounds. The bioactivities of the culture filtrates were similar to those of gliotoxin. The fungal culture filtrate reduced the survival of infected mice, but the filtrate itself did not cause the death of mice. However, all the bioactivities could not be accounted for by gliotoxin itself. These results indicate that gliotoxin in the culture filtrates may be responsible for part of the immunosuppressive activity, but some other components produced by A. fumigatus contribute, in an additive or synergistic manner, to the virulence of the fungus.

Animals↗
PubMed2003

In vitro antifungal activity of Micafungin (FK463) against dimorphic fungi: comparison of yeast-like and mycelial forms.

The characteristics of in vitro micafungin (FK463) antifungal activity against six species of dimorphic fungi were investigated in accordance with the NCCLS M27-A microdilution methods. MICs of micafungin, amphotericin B, itraconazole, and fluconazole for Histoplasma capsulatum var. capsulatum, Blastomyces dermatitidis, Paracoccidioides brasiliensis, Penicillium marneffei, and Sporothrix schenckii were determined both for the yeast-like form and mycelial form. Coccidioides immitis was tested only in its mycelial form. We have clearly demonstrated that the in vitro activity of micafungin depends considerably on the growth form of dimorphic fungi. Micafungin exhibited potent activity against the mycelial forms of H. capsulatum, B. dermatitidis, and C. immitis (MIC range, 0.0078 to 0.0625 micro g/ml), while it was very weakly active against their yeast-like forms (MIC range, 32 to >64 micro g/ml). Micafungin was also more active against the mycelial forms than the yeast-like forms of Paracoccidioides brasiliensis, Penicillium marneffei, and S. schenckii. The MICs of amphotericin B were 2 to 5 dilutions lower for the mycelial forms than for the yeast-like forms of B. dermatitidis and Paracoccidioides brasiliensis. There was no apparent difference in the activity of itraconazole between the two forms. The MICs of fluconazole for the yeast-like forms were generally lower than those for the mycelial forms, and considerably so for B. dermatitidis. These results suggest that the growth form employed in antifungal susceptibility testing of dimorphic fungi can considerably influence the interpretation of results. At present, it cannot be judged whether micafungin has clinical usefulness for dimorphic fungus infections, since for most fungi it remains uncertain which growth form correlates better with therapeutic outcome. However, the results of this study warrant further investigations of micafungin as a therapeutic agent for infections caused by dimorphic fungi.

Antifungal Agents↗
PubMed2003

Rapid identification of the genus fonsecaea by PCR with specific oligonucleotide primers.

An oligonucleotide primer set based on internal transcribed spacer regions of ribosomal DNA for PCR which gives the amplicon for only the DNA from Fonsecaea species was designed. This set yielded an amplicon with 333 bp for all strains of Fonsecaea pedrosoi and Fonsecaea compacta examined but no amplicons for related dematiaceous fungi and pathogenic yeasts. PCR using this primer set was considered to be a useful method for the rapid identification of the genus FONSECAEA:

Ascomycota↗
PubMed2003

The role of chlamydospores of Paracoccidioides brasiliensis.

The role of chlamydospores in the conversion process from a mycelial-to-yeast form using the slide culture method was studied. Three clinical isolates and two other isolates from armadillo, belonging to the fungal species Paracoccidioides brasiliensis, were cultured on Sabouraud dextrose agar (SDA), potato dextrose agar (PDA) and brain heart infusion dextrose agar (BHIDA). Initially, the mycelial forms of each isolate were grown at 25 degrees C for 7, 14, 30 or 60 days on slide cultures and then the temperature was shifted to 35 degrees C. Interestingly, the slide cultures of all the isolates at 25 degrees C formed chlamydospores on either SDA or BHIDA, whereas, on PDA medium, aleurioconidia were formed. If the slide cultures on BHIDA were incubated at 35 degrees C for 7 to 14 days, multiple budding forms could be observed. This phenomenon was not evident in the slide cultures of SDA or PDA. The results of this morphological study indicate that in P. brasiliensis, chlamydospores may play an important role in the conversion process from a mycelial-to-yeast form.

Animals↗
PubMed2003

Direct invasion of bones by highly pathogenic fungi in an in vitro model and its ecological significance.

Animal bones after being devitalized at death are strongly resistant to wear and tear and remain in the soil or environment much longer than other organic components from dead animals. Yet over the course of time they seem to disappear and thus our ecological surroundings are not cluttered with bone remnants. Mechanical factors creating compression or friction and chemical factors like pH of the soil and surroundings must together have provided concerted degrading effects. Microorganisms in the soil also help in this process by utilizing the organic components of devitalized bones. Certain highly pathogenic fungi that have been collected from soil from time to time and many other environmental fungi may take part in the degrading of the bone remnants. In this study, several strains from the highly pathogenic dimorphic fungi Coccidioides immitis, Blastomyces dermatitidis, Histoplasma spp., Paracoccidioides brasiliensis and also some strains of dematiaceous fungi (Exophiala spp. and Foncecaea pedrosoi) were inoculated to dissected and devitalized murine long bones that had been placed on solidified water agar plates to see if they would survive, grow and invade the bones. After being kept for 12 weeks at 25 degrees C all the parts of the histological sections of these bones showed invasion by most of the strains used in this study, although the cortical component of the bony architecture seemed to be comparatively resistant to invasion. Their ability to grow and sporulate in the aforementioned nutrient-limiting condition hinted at a possible role of these fungi in the degradation of devitalized bones.

Animals↗
PubMed2003

[Canine histoplasmosis in Japan].

Histoplasmosis is a fungal infection caused by Histoplasma capsulatum and is distributed a worldwide. Although the disease has been treated as an imported mycosis, some autochthonous human, 1 equine and 4 canine cases suggested that the disease is endemic. Histoplasmosis is classified depending on the variety of causative agent. Histoplasmosis farciminosi known as pseudofarcy, is manifested only in Perissodactyla where it invades lymph nodes and lymph ducts, and is recognized by isolation from horses. Historically, Japan was one of the endemic areas of pseudofarcy before World War II, and more than 20,000 cases were recorded in horses used by the military. Interestingly, Japanese canine histoplasmosis uniformly showed skin ulcers and granulomatous lesions on the skin without pulmonary or gastrointestinal involvement, both of which were very similar to pseudofarcy. It was diagnosed as histoplasmosis by the detection of internal transcribed spacer legions of rRNA gene of H. capsulatum from paraffin embedded tissue samples. Furthermore, the fungal isolate from the human case with no history of going abroad or immigrating was identified as H. capsulatum var. farciminosum by a gene sequence. These facts indicated that pseudofarcy is not only an infectious disease in horses, but also a zoonotic fungal infection. Japanese autochthonous canine histoplasmosis might be a heteroecism of pseudofarcy because of its likeness to the human case, the similarity of clinical manifestations and the historical background at this stage.

Animals↗
PubMed2003

Analysis of serotype AD strains from F1 progenies between urease-positive- and negative-strains of Cryptococcus neoformans.

Cryptococcus neoformans is a pathogenic basidiomycete with a defined sexual cycle involving mating between haploid yeast cells with a transient diploid state. We examined F1 progeny from a crossing between the urease-negative strain (environmental isolate, serotype A, mating type alfa, haploid) and a tester strain (B 3502 from NIH of USA; urease-positive, serotype D, mating type a, haploid) for serotype, mating type, ploidy and urease activity, and performed partial sequencing of the urease gene. Phenotypes of the F1 progeny and results of SSCP analyses suggested that the serotype AD strain of the F1 progeny is a hybrid of the parental serotype A and D strains.

Cryptococcus neoformans↗
PubMed2003

Histoplasma capsulatum variety duboisii isolated in Japan from an HIV-infected Ugandan patient.

A strain of Histoplasma capsulatum var. duboisii (deposited as IFM 50954 in Chiba University) was isolated from the cerebrospinal fluid of a female Ugandan patient infected with HIV. The isolate had in vitro urease activity on Christensen's urea agar slants, although the common belief is that H. capsulatum var. duboisii is urease negative, and is, considered one of the characteristic markers that distinguishes the three varieties of H. capsulatum. Forty H. capsulatum var. capsulatum, five H. capsulatum var. duboisii, and five H. capsulatum var. farciminosum isolates were evaluated for urease activity on Christensen's urea agar slants and for other qualitative and quantitative urease assays of activity. All 50 isolates of H. capsulatum used in this study were positive for urease activity, suggesting that urease activity may be universal characteristic of H. capsulatum. We also compared the urease activity and pathogenicity of seven H. capsulatum isolates that convert into yeast-form cells. Although isolate IFM 50954 showed moderate virulence in mice and moderate urease activity among tested H. capsulatum isolates, there was no correlation between level of urease activity and pathogenicity. In addition, scanning electron microscopy revealed that some microconidia of isolate IFM 50954 formed "double-cell" configurations that were attached to each other by narrow bases.

Animals↗
PubMed2003

The epidemiology and mating behavior of Arthroderma benhamiae var. erinacei in household four-toed hedgehogs (Atelerix albiventris) in Japan.

An epidemiological survey of Trichophyton mentagrophytes var. erinacei in the household hedgehog and other rodents was made between January 17, 2002 and February 28, 2002 in Japan. Quills and hairs were collected from sources identified via the internet. The fungus was isolated only from the quills of four-toed hedgehogs (7/18; 39%) from Kanto to Kyushu regions. Isolates were examined morphologically, physiologically and genetically, and identified as T. mentagrophytes var. erinacei anamorph. The isolates were also genetically compared with European hedgehog (Erinaceus europeus)-borne T. mentagrophytes var. erinacei and Kenyan hedgehog (Aterelix albiventris)-borne Arthroderma benhamiae, and their genotypes of the ITS1-5.8S-ITS2 rDNA were all identical. The isolates were crossed with A. benhamiae Americano-European race and African race, A. vanbreuseghemii and A. simii, with the result that they mated only with African race (+) or (-). Mating types of the isolates were (+) in 6 isolates and (-) in one. An intra-isolate mating between one of the 6 plus isolates and the minus one formed abundant mature gymnothesia, the mating type ratio of the F1 progeny was approximately 1:1, and the sib crossings of F1 progeny produced abundant fertile gymnothesia. The present study revealed that the intra-Japanese hedgehog-borne isolate crossing showed complete fertility and that the sexual degeneration pointed out by Takashio (Mycologia 71: 968-976, 1979) did not exist. Two pairs of mating, (+) and (-) mating types of Japanese isolates with (-) and (+) tester strains of A. benhamiae African race formed less gymnothesia, mating type ratios were unbalanced, and sib crossings of F1 progeny produced small gymnothesia containing a low number of asci, pseudogymothesia, or none, respectively. These results show that A. benhamiae var. erinacei, the teleomorph of T. mentagrophytes var. erinacei, belongs to a different mating group (e.g. hedgehog race) than the Americano-European and African races in A. benhamiae.

Animals↗