Biomedical subjects

T Nakase

Publications and source records attributed to T Nakase.

At least 37 records · Page 2Linked to original sources

PubMed2001

Distribution and identification of red yeasts in deep-sea environments around the northwest Pacific Ocean.

We isolated 99 yeast strains, including 40 red yeasts, from benthic animals and sediments collected from the deep-sea floor in various areas in the northwest Pacific Ocean. Comparing the yeast isolates from animals and sediments collected from shallow locations, the proportion of red yeasts differed considerably, comprising 81.5% and 10.6% of the isolates from animals and sediments, respectively. All of the red yeast isolates belonged to the genera Rhodotorula and Sporobolomyces. On the basis of morphological and physiological characteristics, the isolates were identified as R. aurantiaca, R. glutinis, R. minuta and R. mucilaginosa of the genus Rhodotorula, and S. salmonicolor and S. shibatanus of the genus Sporobolomyces. Only R. glutinis and R. mucilaginosa were isolated from sediments. All of the others were isolated from animal sources. Phylogenetic analyses based on internal transcribed spacer (ITS) regions and 5.8S rRNA gene sequences allowed us to establish the precise taxonomic placement of each of the isolates and thereby investigate the intraspecific relationships among the isolates. Twenty-two strains identified as members of R. glutinis, which showed a wide distribution in the deep-sea, and five isolates identified as R. minuta, which were isolated only from benthic animals, showed substantial heterogeneity within the species. The isolates phenotypically identified as Sporobolomyces species and R. mucilaginosa phylogenetically occupied the placements corresponding to these species. Some strains assigned to known species on the basis of phenotypic features should be regarded as new species as suggested by the results of molecular analysis.

Ascomycota↗

PubMed2001

Rhodotorula lamellibrachii sp. nov., a new yeast species from a tubeworm collected at the deep-sea floor in Sagami bay and its phylogenetic analysis.

A new species of the genus Rhodotorula was isolated from a tubeworm (Lamellibrachia sp.) collected at a depth of 1156 m in Sagami Bay, Japan. Strain SY-89 had physiological properties quite similar to R. aurantiaca. Two phylogenetic trees, one based on internal transcribed spacer (ITS) regions and 5.8S rDNA sequences and the other based on the D1/D2 region of the large subunit (26S) rDNA sequences, united strain SY-89 to the type strain of Sakaguchia dacryoides through a considerable evolutionary distance. Strain SY-89 was differentiated from S. dacryoides by the G+C content of the nuclear DNA and differences in the ability to utilize specific carbon and nitrogen compounds. The low complementarity of strain SY-89 DNA to that of the type strain of S. dacryoides confirmed that this strain was genetically unrelated to previously known species. The tubeworm isolates are described as R. lamellibrachii sp. nov. The type strain of R. lamellibrachii is strain SY-89 (= JCM 10907). R. lamellibrachii formed a cluster with Erythrobasidium hasegawianum, R. lactosa, S. dacryoides and Sporobolomyces elongatus on the ITS and 5.8S rDNA phylogenetic tree. These five species shared a signature sequence in 26S rDNA, although this relationship was not supported by phylogeny based on the D1/D2 region of 26S rDNA.

Animals↗

PubMed2001

Expression of proteinases and inflammatory cytokines in subchondral bone regions in the destructive joint of rheumatoid arthritis.

OBJECTIVE: We previously described abnormalities in the bone marrow of patients with rheumatoid arthritis (RA), but were able to shed little light on the pathogenic roles of inflammatory cytokines and proteinases in joint destruction in the subchondral region in RA. This is the first report to describe the co-localization of cytokines and proteinases in this area. METHODS: Decalcified paraffin-embedded sections from 10 patients with RA and five patients with osteoarthritis (OA) were examined for the immunolocalization of cathepsins B, K and L and the localization of messenger RNAs for interleukin 1beta (IL-1beta), tumour necrosis factor alpha (TNF-alpha) and matrix metalloproteinase 9 (MMP-9). The cells were double-stained with anti-CD68 or anti-prolyl 4-hydroxylase (PH) antibody. RESULTS: An immunohistochemical study confirmed the expression of cathepsins B and L by CD68-positive mononuclear cells at the sites of significant cartilage and bone erosion from the subchondral region in all RA specimens. Osteoclast-like cells showed intense staining for cathepsin K and MMP-9. Osteoblast-like cells strongly expressed MMP-9. Analysis of serial sections revealed that expression of the IL-1beta and TNF-alpha genes occurred near that of the cathepsins and MMP-9 in the subchondral region. CONCLUSION: We conclude that inflammatory cytokines and tissue-damaging proteinases play important roles in joint destruction in the subchondral region in RA.

Adult↗

PubMed2001

Sporobolomyces yunnanensis sp. nov., a Q-10(H2)-containing yeast species with a close phylogenetic relationship to Erythrobasidium hasegawianum.

A ballistoconidia-forming yeast strain, CH 2.141T, isolated from a semi-dried leaf sample collected in Yunnan, China, was found to have Q-10(H2) as its major ubiquinone. Molecular phylogenetic analysis based on the nucleotide sequences of small subunit (18S) rDNA and the internal transcribed spacer region (including 5.8S rDNA) indicated that the strain was closely related to the two described Q-10(H2)-containing yeast species, Erythrobasidium hasegawianum and Sporobolomyces elongatus, with a closer relationship to the former. A DNA-DNA reassociation experiment showed that strain CH 2.141T represents a new yeast species, for which the name Sporobolomyces yunnanensis sp. nov. is proposed.

Basidiomycota↗

PubMed2001

Bensingtonia thailandica sp. nov., a novel basidiomycetous yeast species isolated from plant leaves in Thailand.

Ten strains which were characterized by the formation of ballistoconidia, the absence of xylose in whole-cell hydrolysates, the presence of Q-9 as the major ubiquinone isoprenologue, the inability to ferment sugars and positive diazonium blue B and urease reactions were isolated from plant samples collected in Thailand. These isolates were closely related to Bensingtonia phyllada based on the analysis of 18S rDNA sequences. On the basis of the morphological, physiological and chemotaxonomic properties, the 10 isolates were assigned to the genus Bensingtonia. DNA complementarity showed that these isolates were genetically distinct from known species of the genus Bensingtonia. The isolates are described as Bensingtonia thailandica sp. nov. The type strain is strain TY-138T (= JCM 10651T).

Basidiomycota↗

PubMed2001

Two new yeasts, Trichosporon debeurmannianum sp. nov. and Trichosporon dermatis sp. nov., transferred from the Cryptococcus humicola complex.

Cryptococcus humicola, as currently defined, shows intraspecific rRNA gene sequence differences. Three strains of this species produced arthroconidia on cornmeal agar and belonged to the genus Trichosporon in a molecular phylogeny. They clustered with the species possessing Q10 as the major ubiquinone and were serotype I. Sequence analyses clearly revealed that they were two new Trichosporon species. The names Trichosporon dermatis sp. nov. (= CBS 2043T) and Trichosporon debeurmannianum sp. nov. (= CBS 1896T) are proposed for these strains.

Antifungal Agents↗

PubMed2001

Natronobacterium nitratireducens sp. nov., a aloalkaliphilic archaeon isolated from a soda lake in China.

Two novel haloalkaliphilic archaea, strains C231T and C42, were isolated from a soda lake in China. Cells of the two strains were rod-shaped and gram-negative and colonies were bright red. They required at least 2.5 M NaCl for growth, with an optimum at 3.5 M NaCl, and grew over a pH range from 8.0 to 10.5, with an optimum at pH 8.5. Hypotonic treatment with less than 1.5 M NaCl caused cell lysis. They had similar polar lipid compositions, possessing the diphytanyl (C20:C20) and phytanyl-sesterterpanyl (C20:C25) diether derivatives of phosphatidylglycerol and phosphatidylglycerophosphate methyl ester and a minor phospholipid, PL1. No glycolipids were detected. Comparison of 16S rDNA sequences and morphological features placed them in the genus Natronobacterium. Detailed phenotypic characterization and DNA-DNA hybridization studies revealed that the two strains belong to a new species in the genus Natronobacterium, for which the name Natronobacterium nitratireducens sp. nov. is proposed. The type strain is C231T (= AS 1.1980T = JCM 10879T).

China↗

PubMed2001

Phylogenetic analysis of strains originally assigned to Bullera variabilis: descriptions of Bullera pseudohuiaensis sp. nov., Bullera komagatae sp. nov. and Bullera pseudoschimicola sp. nov.

Twenty strains previously assigned to the species Bullera variabilis Nakase & Suzuki were reclassified using a molecular taxonomic approach. The strains were regrouped first by nucleotide sequence comparison of the rDNA internal transcribed spacer (ITS) regions, including the 5.8S gene. Phylogenetic positions of B. variabilis strains with different ITS region sequences were then analysed based on their 18S rDNA sequences. The taxonomic status of the original Bullera variabilis strains was clarified further by DNA-DNA hybridization experiments. Of the 20 strains studied, five remained in the species B. variabilis, six strains were reassigned to the species Bullera mrakii and three novel species were proposed for eight of the nine remaining strains, namely Bullera pseudohuiaensis sp. nov. (one strain; type strain JCM 5984T = AS 2.2203T), Bullera komagatae sp. nov. (one strain; type strain JCM 5983T = AS 2.2202T) and Bullera pseudoschimicola sp. nov. (six strains; type strain JCM 391ST = AS 2.2201T). The remaining strain, JCM 6140, was closely related to B. pseudoschimicola. However, differences in ITS region sequences between strain JCM 6140 and strains of B. pseudoschimicola, and the intermediate DNA-DNA relatedness to representative strains of B. pseudoschimicola did not allow a definite taxonomic decision to be made for strain JCM 6140.

Basidiomycota↗

PubMed2001

Reclassification of the Cryptococcus humicola complex.

Ten strains of the Cryptococcus humicola complex were reclassified on the basis of sequence analyses of 18S rDNA and internal transcribed spacer regions and DNA-DNA reassociation experiments. They were differentiated into seven species including C humicola. Five novel species are proposed: Cryptococcus daszewskae sp. nov. (type strain CBS 5123T = JCM 11166T = MUCL 30649T), Cryptococcus fragicola sp. nov. (type strain JCM 1530TT = CBS 88981), Cryptococcus longus sp. nov. (type strain CBS 5920T = JCM 11167T = MUCL 30690T), Cryptococcus musci sp. nov. (type strain JCM 1531T = CBS 8899T) and Cryptococcus pseudolongus sp. nov. (type strain JCM 9712T = CBS 8297T). A syntype of Sporobolomyces albidus JCM 1460T is also revealed to be a distinct species; the name Cryptococcus ramirezgomezianus nom. nov. is therefore proposed for Sporobolomyces albidus Ramírez Gómez (type strain IJFM 502T = CBS 2839T = JCM 1460T = NRRL Y-2478T), since the name Cryptococcus albidus (Saito) C. E. Skinner has already been recognized for a distinct species within the genus Cryptococcus. Strains possessing either Q-9 or Q-10 have been reported to occur in C. humicola; however, after reclassification, the ubiquinone type of the species in each phylogenetic group was shown to be uniform, indicating that it is a useful criterion for the taxonomy of the Trichosporonales.

Base Sequence↗

PubMed2001

Intraspecies diversity of Cryptococcus albidus isolated from humans as revealed by sequences of the internal transcribed spacer regions.

The basidiomycetous yeast, Cryptococcus albidus, shows intraspecies diversity, but it is rarely isolated from immunocompromised patients. Nineteen strains of C. albidus, including nine clinical isolates, were re-classified by sequences of their rRNA internal transcribed spacer (ITS) regions. The nine clinical isolates were genetically diverse and included both C. albidus and C. diffluens. One clinical isolate, recovered from the blood of an AIDS patient, represented a new species. Only small differences were found in the biochemical and serological characteristics of C. albidus and C. diffluens. All isolates were sensitive to amphotericin B, but several isolates were resistant to fluconazole and itraconazole. C. albidus heterogeneity should be taken into consideration when identifying clinical isolates.

AIDS-Related Opportunistic Infections↗

PubMed2001

Description of Bullera kunmingensis sp. nov., and clarification of the taxonomic status of Bullera sinensis and its synonyms based on molecular phylogenetic analysis.

A ballistoconidium-forming yeast strain, CH 2.506, isolated from a semi-dried leaf of Parthenocissus sp. collected near Kunming City in Yunnan, China, was shown to be closely related to the non-ballistoconidium-forming species Cryptococcus luteolus (Saito) C.E. Skinner and the ballistoconidium-forming species Bullera sinensis Li by molecular phylogenetic analysis based on 18S rDNA sequencing. This strain was demonstrated to represent a distinct undescribed yeast species by internal transcribed spacer (ITS) region sequence and G+C content comparison and DNA-DNA relatedness, for which the name Bullera kunmingensis sp. nov. is proposed. Meanwhile, the taxonomic relationships among Bullera sinensis and its synonyms B. derxii Nakase & Suzuki and B. alba (Hanna) Derx var. lactis Li, were clarified on the basis of molecular phylogenetic analysis and DNA-DNA reassociation. B. derxii was confirmed to be conspecific with B. sinensis, while B. alba var. lactis was shown to represent a variety of B. sinensis. A new combination, Bullera sinensis Li var. lactis (Li) Bai, Takashima et Nakase, is therefore proposed. Comparative analysis of different types of molecular criteria employed in the present study suggested that when inferring phylogenetic relationships among sibling taxa, sequence data from ITS regions should be interpreted with caution.

Base Composition↗

PubMed2001

A neuroprotective role for gap junctions.

Glial-neuronal interactions have been implicated in both normal information processing and neuroprotection. One pathway of cellular interactions involves gap junctional intercellular communication (GJIC). In astrocytes, gap junctions are composed primarily of the channel protein, connexin43 (Cx43), and provide a substrate for formation of a functional syncytium implicated in the process of spatial buffering in the CNS. Thus gap junctional communication may be neuroprotective following a CNS insult that entails glutamate cytotoxicity (i.e. ischemia). We have shown that blocking gap junctions during a glutamate insult to co-cultures of astrocytes and neurons results in increased neuronal injury. To assess the effect of reduced Cx43 and GJIC on neuroprotection, we examined brain infarct volume in wild type and Cx43 heterozygote null mice following focal ischemia. Cx43 heterozygous null mice exhibited a significantly larger infarct volume compared to wild type. At the cellular level, a significant increase in TUNEL positive cells was observed in the penumbral region of the Cx43 heterozygote mice. These results suggest that augmentation of GJIC in astrocytes may contribute to neuroprotection following ischemic injury. These findings support the hypothesis that gap junctions play a neuroprotective role against glutamate cytotoxicity.

Animals↗

PubMed2001

Distribution of genes for bone morphogenetic protein-4, -6, growth differentiation factor-5, and bone morphogenetic protein receptors in the process of experimental spondylosis in mice.

OBJECT: Because little is known about the molecular mechanisms underlying the process of spondylosis, the authors examined the extent of genetic localization of several members of bone morphogenetic protein (BMP) and BMP receptors in chondrogenesis during the process of inducing spondylosis in their previously established experimental mice model. METHODS: Experimental spondylosis was induced in 5-week-old ICR mice. The cervical spine was harvested chronologically, and histological sections were prepared. Messenger RNA for BMP-4, growth and differentiation (GDF)-5, BMP-6, and BMP receptors (ALK-3, -6, and BMP-RII) was localized in the tissue sections by in situ hybridization. In the early stage, BMP-4-derived mRNA was localized mainly in cells in the anterior margin of the cervical discs, together with ALK-6 and BMP-RII mRNA. No GDF-5 and BMP-6 mRNA was detected at this stage. In the late stage, cells positive for BMP-4 decreased, whereas GDF-5 and BMP-6 mRNA were localized in cells undergoing chondrogenesis. The ALK-3 mRNA began to appear in this stage, as did ALK-6 and BMP-RII. CONCLUSIONS: The localization of transcripts for BMP-4, -6, and GDF-5 as well as BMP receptors shown during the present experimental model indicate the possible involvement of molecular signaling by these BMPs in the chondrogenic progress in spondylosis.

Animals↗

PubMed2001

Localization of cathepsins G and L in spontaneous resorption of intervertebral discs in a rat experimental model.

To determine the involvement of cathepsins G and L in the mechanism of spontaneous resorption of herniated intervertebral discs, localization of these cathepsins in this process was examined immunohistochemically using a rat model of autologous transplantation of coccygeal discs. Rat coccygeal discs were resected and autotransplanted into the subcutaneous space of the skin of the back. Paraffin-embedded sections of intervertebral disc tissue, harvested at various post-transplantational periods, were immunohistochemically stained with antibodies for cathepsin G, cathepsin L, MMP-1, MMP-3 and ED-2. The number of positive cells was counted in each part of the transplanted discs. Immunolocalization of cathepsins G and L in various types of disc cells was first observed early in the post-transplantation period. From two days after the operation, histology showed invasion by granulation tissue, with many macrophages, in all sections. Subsequently, the number of macrophages in granulation tissue was observed to increase, along with a gradual increase in the percentage of cells positive for MMP-1 and MMP-3. In addition to the ability of cathepsins G and L to degrade major extracellular matrix components of intervertebral discs, cathepsin G is capable of activating latent pro-MMPs. The up-regulation of cathepsins G and L in the intervertebral disc tissue in this spontaneous resorption model suggests that these proteinases may be involved in degradation of extracellular matrix, leading to the natural resorption of herniated discs.

Journal Article↗

PubMed2001

[Bone marrow plays an important role in joint destruction in patients with rheumatoid arthritis].

In iliac bone marrow the absolute number of mononuclear cells (MNCs) was increased in RA patients compared with the non-RA controls. In CD8 positive cell and myeloid cell fractions, significant differences were recognized between RA patients and non-RA controls. The presence of abnormal myeloid lineage cells in epiphyseal bone marrow adjacent to joints affected with severe RA was shown. Stroma cell lines from RA bone marrow with nursing activity were established and shown to play a pivotal role in the pathogenesis in RA bone marrow. Histologic study also shows that subchondral region expressing tissue-damaging proteinases plays an important role in joint destruction in RA.

English Abstract↗

PubMed2000

[Humeral lengthening and deformity correction].

Nine patients with achondroplasia and one patient with Apert syndrome underwent the surgical lengthening of both humerus and simultaneous correction of both associated bone deformity. An unilateral external fixator was applied to the lateral aspect of the humerus with four half-pins and percutaneous predrilling osteotomy was performed at the apex of flexion deformity of the bone. During the waiting period before distraction, the flexion deformity of the distal humerus was corrected using an additional external fixator. Slow gradual distraction was subsequently carried out at a rate of 0. 25 mm every 6 hours. The average lengthening was 8 cm (range 7.5 to 9 cm), the overall treatment time 312 days (range 192 to 406 days), and the average healing index 39.0 days/cm. The average correction of the elbow flexion deformity was 20 degrees. We believe this treatment is useful to improve the function of the arms and the activity of daily living for the patients with bilateral short humeri.

Achondroplasia↗

PubMed2000

Congenital transverse deficiency of the tibia and fibula: a report of two cases.

We report two similar, but unrelated, patients with congenital bilateral partial deficiencies of the tibia and fibula associated with intact feet. In both patients, the tibia and fibula were absent on initial radiographs, while the femur and the tarsal bones were well developed and there was bilateral teratologic dislocation of the hips. Ultrasound and magnetic resonance imaging (MRI) studies suggested the presence of cartilaginous remnants of the tibia and fibula. There were multidirectional instabilities in the knees and ankles. The clinical and radiological features of these cases are distinct from those of congenital longitudinal deficiency of the tibia, in which the fibula is always preserved, and from longitudinal deficiency of the fibula, in which the tibia is present and the foot is usually involved. We suggest that the bilateral partial deficiencies of the tibia and fibula associated with the intact foot and teratologic dislocation of the hips is a single-entity disorder, possibly categorized as an intercalary transverse deficiency of the lower limb.

Abnormalities, Multiple↗

PubMed2000

Pathology of femoral head collapse following transtrochanteric rotational osteotomy for osteonecrosis.

We investigated the pathology of femoral head collapse following transtrochanteric anterior rotational osteotomy. Six femoral heads were obtained during total hip arthroplasty some 2-12 years after osteotomy. In all cases, the preoperatively necrotic lesions exhibited mostly osteonecrosis with accumulation of bone marrow cell debris and trabecular bone with empty lacunae, although repair tissue such as granulation tissue and appositional bone formation were observed in limited areas in some cases. In the transposed intact articular surface of the femoral head, osteoarthritic changes such as fissure penetration to the subchondral bone and osteophyte formation were commonly observed. In newly created subchondral areas at weight-bearing sites, trabecular thickness and the number of trabecular bones had decreased, with few osteoblasts, osteoclasts, and osteocytes being present, resulting in a coarse lamellar structure of the trabecular bone. These findings suggest that transposed areas in cases of failure consist mostly of low-turnover osteoporotic lesions which could cause collapse of the femoral head.

Adult↗