Biomedical subjects

C Kato

Publications and source records attributed to C Kato.

At least 73 records · Page 4Linked to original sources

PubMed1999

[Clinical evaluation of acute and chronic pulmonary thromboembolism using intravascular ultrasound and angioscopy].

Pulmonary artery thrombi and parietal lesions were observed in 13 patients (mean age 58 +/- 18 years) with acute pulmonary thromboembolism (n = 4) and chronic pulmonary thromboembolism (n = 9) using intravascular ultrasound and angioscopy at the time of right heart catheterization. Patients with acute pulmonary thromboembolism without underlying disease mainly had non-echogenic intraluminal mass, and good pulsatile vessel without intimal thickening. Angioscopy directly showed red thrombi with white fibrin coating, and no parietal lesions. Patients with chronic pulmonary thromboembolism could be classified into 3 groups: 1) Poor extensibility of the vessel wall and intimal thickening with non-echogenic thrombi on intravascular ultrasound, and relatively fresh parietal thrombi consisting of a mixture of red blood cell and fibrin, and spider web-like fibrin net on angioscopy (6 patients). 2) Crescent parietal thrombi and wall irregularity on intravascular ultrasound, and probably organized thrombi with a mixture of red and white surface on angioscopy (one patient). 3) Marked and echogenic intimal thickening and poor extensibility on intravascular ultrasound, and intimal surface irregularities and yellowish changes on angioscopy (one patient). All patients suffering acute deterioration in the chronic phase belonged to groups 1) or 2). Intravascular ultrasound and angioscopy are useful for characterizing the thrombi and related pulmonary artery lesions in patients with pulmonary thromboembolism. The pulmonary artery intima and thrombus differ between acute and chronic pulmonary thromboembolism.

Acute Disease↗

PubMed1999

Pressure response in deep-sea piezophilic bacteria.

Several piezophilic bacteria have been isolated from deep-sea environments under high hydrostatic pressure. Taxonomic studies of the isolates showed that the piezophilic bacteria are not widely distributed in terms of taxonomic positions, and all were assigned to particular branches of the Proteobacteria gamma-subgroup. A pressure-regulated operon from piezophilic bacteria of the genus Shewanella, S. benthica and S. violacea, was cloned and sequenced, and downstream of this operon another pressure regulated operon, cydD-C, was found. The cydD gene was found to be essential for the bacterial growth under high-pressure conditions, and the product of this gene was found to play a role in their respiratory system. Results obtained later indicated that the respiratory system in piezophilic bacteria may be important for survival in a high-pressure environment, and more studies focusing on other components of the respiratory chain have been conducted. These studies suggested that piezophilic bacteria are capable of changing their respiratory system in response to pressure conditions, and a proposed respiratory chain model has been suggested in this regard.

Bacterial Proteins↗

PubMed1998

Distribution of the pressure-regulated operons in deep-sea bacteria.

DNA regions corresponding to portions of two different pressure-regulated operons previously identified in two deep-sea barophilic bacteria were separately PCR amplified from a variety of deep-sea microorganisms and sequenced. With the two sets of primers employed, amplification was particularly successful from the more barophilic bacteria examined. 16S rRNA sequence analysis revealed that these bacteria are all phylogenetically related and belong in a sub-branch of the genus Shewanella containing only the deep-sea Shewanella barophilic bacteria. We define this sub-branch as the 'Shewanella barophile branch' containing at least two different species. Our results suggest that the DNA sequences of the pressure-regulated operons can be regarded as marker sequences to identify the Shewanella barophilic strains.

Amino Acid Sequence↗

PubMed1998

Taxonomic studies of deep-sea barophilic Shewanella strains and description of Shewanella violacea sp. nov.

Several barophilic Shewanella species have been isolated from deep-sea sediments at depths of 2,485-6,499 m. From the results of taxonomic studies, all of these isolates have been identified as strains of Shewanella benthica except for strain DSS12. Strain DSS12 is a member of a novel, moderately barophilic Shewanella species isolated from the Ryukyu Trench at a depth of 5,110 m. On Marine Agar 2216 plates, this organism produced a violet pigment, whereas the colonies of other isolates (S. benthica) were rose-colored. Phylogenetic analysis based on 16 S ribosomal RNA gene sequences showed that strain DSS12 represents a separate lineage within the genus Shewanella that is closely related to S. benthica and particularly to the members of the Shewanella barophiles branch. The temperature range for growth and some of the biochemical characteristics indicate that strain DSS12 differs from other Shewanella species. Furthermore, strain DSS12 displayed a low level of DNA similarity to the Shewanella type strains. Based on these differences, it is proposed that strain DSS12 represents a new deep-sea Shewanella species. The name Shewanella violacea (JCM 10179) is proposed.

Bacteria, Anaerobic↗

PubMed1998

Photobacterium profundum sp. nov., a new, moderately barophilic bacterial species isolated from a deep-sea sediment.

A novel, moderately barophilic bacterium was isolated from a sediment sample obtained from the Ryukyu Trench, at a depth of 5110 m. The isolate, designated strain DSJ4, is a Gram-negative rod capable of growth between 4 degrees C and 18 degrees C under atmospheric pressure, with optimum growth displayed at 10 degrees C, and capable of growth at pressures between 0.1 MPa and 70 MPa at 10 degrees C, with optimum growth displayed at 10 MPa. Strain DSJ4 is a moderately barophilic bacterium, and shows no significant change in growth at pressures up to 50 MPa. Phylogenetic analysis of the 16S rRNA sequence of strain DSJ4 places this strain within the Photobacterium subgroup of the family Vibrionaceae, closely related to the strain SS9 that was independently isolated from the Sulu Trough. The temperature and pressure ranges for growth, cellular fatty acid composition, and assorted physiological and biochemical characteristics indicate that these strains differ from other Photobacterium species. Furthermore, both SS9 and DSJ4 displayed a low level of DNA similarity to other Photobacterium type strains. Based on these differences, these strains are proposed to represent a new deep-sea-type species. The name Photobacterium profundum (JCM10084) is proposed.

Base Composition↗

PubMed1998

Purification of a ccb-type quinol oxidase specifically induced in a deep-sea barophilic bacterium, Shewanella sp. strain DB-172F.

We investigated for the first time the respiratory chain system of a deep-sea barophilic bacterium, Shewanella sp. strain DB-172F. A membrane-bound ccb-type quinol oxidase, from cells grown at 60 MPa pressure, was purified to an electrophoretically homogeneous state. The purified enzyme complex consisted of four kinds of subunits with molecular masses of 98, 66, 18.5, and 15kDa, and it contained 0.96 mol of protoheme and 1.95mol of covalently bound heme c per mol of enzyme. Only protoheme in the enzyme reacted with CO and CN-, and the catalytic activity of the enzyme was 50% inhibited by 4 microM CN-. The isoelectric point of the native enzyme complex was determined to be 5.0. This enzyme was specifically induced only under conditions of elevated hydrostatic pressure, and high levels were expressed in cells grown at 60 MPa. The membranes isolated from cells grown at atmospheric pressure (0.1 MPa) exhibited high levels of both cytochrome c oxidase and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPDH2)-oxidase activity. These results suggest the presence of two kinds of respiratory chains regulated in response to pressure in the deep-sea bacterium DB-172F.

Bacteria↗

PubMed1998

Pyrococcus horikoshii sp. nov., a hyperthermophilic archaeon isolated from a hydrothermal vent at the Okinawa Trough.

A hyperthermophilic, anaerobic archaeon was isolated from hydrothermal fluid samples obtained at the Okinawa Trough vents in the NE Pacific Ocean, at a depth of 1395m. The strain is obligately heterotrophic, and utilizes complex proteinaceous media (peptone, tryptone, or yeast extract), or a 21-amino-acid mixture supplemented with vitamins, as growth substrates. Sulfur greatly enhances growth. The cells are irregular cocci with a tuft of flagella, growing optimally at 98 degrees C (maximum growth temperature 102 degrees C), but capable of prolonged survival at 105 degrees C. Optimum growth was at pH 7 (range 5-8) and NaCl concentration 2.4% (range 1%-5%). Tryptophan was required for growth, in contrast to the closely related strains Pyrococcus furiosus and P. abyssi. Thin sections of the cell, viewed by transmission electron microscopy, revealed a periplasmic space similar in appearance to the envelope of P. furiosus. The predominant cell membrane component was tetraether lipid, with minor amounts of diether lipids. Treatment of the cells by mild osmotic shock released an extract that contained a Zn(2+)-dependent alkaline phosphatase. Phylogenetic analysis of the sequences encoding 16S rRNA and glutamate dehydrogenase places the isolate with certainty within the genus Pyrococcus although there is relatively low DNA-DNA hybridization (< 63%) with described species of this genus. Based on the reported results, we propose a new species, to be named Pyrococcus horikoshii sp.nov.

Japan↗

PubMed1998

Mechanisms of gene expression controlled by pressure in deep-sea microorganisms.

A pressure-regulated operon has been cloned and sequenced from deep-sea barophilic Shewanella strains. To understand pressure-regulated mechanisms of gene expression, a regulatory element upstream of the pressure-regulated operon from Shewanella sp. strain DSS12 was studied. Regions A and B were classified by sequence analysis. A unique octamer motif, AAGGTAAG, was found to be repeated in tandem 13 times in region B. An electrophoretic mobility shift assay demonstrated that a O54-like factor recognizes region A and other unknown factors recognize region B. Different shift patterns of the protein-DNA complexes were observed when extracts of cells cultured at 0.1 MPa or 50 MPa were incubated with a DNA probe specific for region B. These results indicate that the deep-sea strain DSS12 expresses different DNA-binding factors under different pressure conditions.

Bacterial Proteins↗

PubMed1998

Taxonomy and biotransformation activities of some deep-sea actinomycetes.

Deep-sea soft sediments from trench systems and depths in the northwestern Pacific Ocean ranging from less than 300 to 10,897 m in depth have been analyzed for three target genera of actinomycetes: Micromonospora, Rhodococcus, and Streptomyces. Only culturable strains, recovered at atmospheric pressure on selective isolation media, have been examined to date. Maximum recoveries of culturable bacteria were greater that 10(7)/ml wet g sediment, but actinomycetes comprised a small proportion of this population (usually less than 1%). The target actinomycetes were isolated at all depths except from the Mariana Trench sediments. Actinomycete colonies were defined initially on the basis of colony morphologies, and preliminary identification then was made by chemotaxonomic tests. Pyrolysis mass spectrometry (PyMS) of deep-sea mycolic acid-containing actinomycetes gave excellent correspondence with numerical (phenetic) taxonomic analyses and subsequently was adopted as a rapid procedure for assessing taxonomic diversity. PyMS analysis enabled several clusters of deep-sea rhodococci to be distinguished that are quite distinct from all type strains. 16S rRNA gene sequence analysis has revealed that several of these marine rhodococci have sequences that are very similar to certain terrestrial species of Rhodococcus and to Dietzia. There is evidence for the intrusion of terrestrial runoff into these deep trench systems, and the inconsistency of the phenotypic and molecular taxonomies may reflect recent speciatiion events in actinomycetes under the high-pressure conditions of the deep sea. The results of DNA-DNA pairing experiments point to the novelty of Rhodococcus strains recovered from hadal depths in the Izu Bonin Trench. Biotransformation studies of deep-sea bacteria have focused on nitrile compounds. Nitrile-metabolizing bacteria, closely related to rhodococci, have been isolated that grow well at low temperature, high salt concentrations, and high pressures, suggesting that they are of marine origin or have adapted to the deep-sea environment.

Actinomycetales↗

PubMed1998

Extremely barophilic bacteria isolated from the Mariana Trench, Challenger Deep, at a depth of 11,000 meters.

Two strains of obligately barophilic bacteria were isolated from a sample of the world's deepest sediment, which was obtained by the unmanned deep-sea submersible Kaiko in the Mariana Trench, Challenger Deep, at a depth of 10,898 m. From the results of phylogenetic analysis based on 16S rRNA gene sequences, DNA-DNA relatedness study, and analysis of fatty acid composition, the first strain (DB21MT-2) appears to be most highly similar to Shewanella benthica and close relatives, and the second strain (DB21MT-5) appears to be closely related to the genus Moritella. The optimal pressure conditions for growth of these isolates were 70 MPa for strain DB21MT-2 and 80 MPa for strain DB21MT-5, and no growth was detected at pressures of less than 50 MPa with either strain. This is the first evidence of the existence of an extreme-barophile bacterium of the genus Moritella isolated from the deep-sea environment.

Bacteria↗

PubMed1998

A rapid method for disrupting genes in the Escherichia coli genome.

The entire genomic sequence of Escherichia coli has recently been completed. To gain insight into the function of the vast array of yet uncharacterized open reading frames (ORFs), a variety of new genetic tools will be required. Here we examined a genetic system, using an integration plasmid vector (named pINT007), for rapid construction of disruption mutants of any ORF in E. coli. It was found that the vector allows us to rapidly construct a disruption mutant for any gene on the chromosome as a cointegrate, furthermore, resolution of the resulting cointegrate can be surely accomplished by using a pair of the bla (ampicillin resistant) genes on the vector as a positive-selection marker.

Escherichia coli↗

PubMed1998

[Outcomes of 50 leukemia patients who received bone marrow transplants from unrelated donors].

Fifty leukemia patients were given bone marrow transplants (BMTs) from unrelated donors at Meitetsu Hospital. We studied the outcomes of their transplants from two perspectives: leukemia disease stage and acute graft versus host disease (GVHD). The probability of disease-free survival for standard-risk, high-risk, and super-high risk patients was 65%, 29%, and 8%, respectively. The main causes of death were septicemia, cardiac and renal failure, and relapse of leukemia in the high- and super-high risk patients, and grade III-IV acute GVHD in the standard-risk patients. The incidence of grade II-IV and grade III-IV acute GVHD was 32% and 17%, respectively. All 7 patients in whom grade III-IV severe acute GVHD developed died. We conclude that better control of acute GVHD and treatment of early stage complications are clearly important to improving the outcome of BMTs from unrelated donors, especially for high and super-high risk patients.

Acute Disease↗

PubMed1997

Cloning of cDNAs encoding G protein-coupled receptor expressed in human endothelial cells exposed to fluid shear stress.

A cDNA library of human umbilical vein endothelial cells exposed to fluid shear stress was constructed to search for functional endothelial genes expressed under flow conditions, and cDNAs encoding members of the G protein-coupled receptor (GPCR) family were cloned by a polymerase chain reaction (PCR) method using degenerate oligonucleotide primers. One of the two GPCR clones obtained was edg-1, and the other clone is a novel gene named FEG-1 that encodes a 375-amino acid protein similar to the receptors for both angiotensin II and chemokines. Reverse transcriptase-PCR showed that the FEG-1 and edg-1 mRNA levels in endothelial cells increased markedly in response to fluid flow. This suggests that FEG-1 and edg-1 may be receptor genes that play important roles in the regulation of endothelial function under physiological blood flow conditions.

Amino Acid Sequence↗

PubMed1997

Pressure and temperature effects on growth and viability of the hyperthermophilic archaeon Thermococcus peptonophilus.

We studied the effects of high temperatures and elevated hydrostatic pressures on the physiological behavior and viability of the extremely thermophilic deep-sea archaeon Thermococcus peptonophilus. Maximal growth rates were observed at 30 and 45 MPa although no significant increases in cell yields were detected. Growth at 60 MPa was slower. The optimal growth temperature shifted from 85 degrees C at 30 MPa to 90-95 degrees C at 45 MPa. Cell viability during the stationary phase was also enhanced under high pressure. A trend towards barophily at pressures greater than those encountered in situ at the sea floor was demonstrated at increasing growth temperatures. The viability of cells during starvation, at high temperature (90, 95 degrees C), and at low temperature (10 degrees C) was enhanced at 30 and 45 MPa as compared to atmospheric pressure. These results show that the extremely thermophilic archaeon T. peptonophilus is a barophile.

Adenosine Triphosphate↗

PubMed1997

The molecular biology of barophilic bacteria.

Many microorganisms from the deep-sea display high-pressure-adapted--also described as barophilic or piezophilic--growth characteristics. Phylogenetic studies have revealed that a large proportion of the barophilic bacteria currently in culture collections belong to a distinct subgroup of the genus Shewanella, referred to as the "barophile branch." Many of the basic properties of barophiles that enable their survival at extremes of pressure remain to be elucidated. However, several genes whose expression is regulated by pressure, or which appear to be critical to baroadaptation, have been uncovered. One such operon, whose presence appears to be restricted to the "barophile branch," has been identified in DNA samples obtained from sediments recovered in the deepest ocean trench. In the case of another set of pressure-regulated genes, regulatory elements required for pressure signaling have been uncovered. The nature and regulation of these genes is discussed.

Genes, Bacterial↗

PubMed1997

Molecular analyses of the sediment of the 11,000-m deep Mariana Trench.

We have obtained sediment samples from the world's deepest sea-bottom, the Mariana Trench challenger point at a depth of 10,898 m, using the new unmanned submersible Kaiko. DNA was extracted from the sediment, and DNA fragments encoding several prokaryotic ribosomal RNA small-subunit sequences and pressure-regulated gene clusters, typically identified in deep-sea adapted bacteria, were amplified by the polymerase chain reaction. From the sequencing results, at least two kinds of bacterial 16S rRNAs closely related to those of the genus Pseudomonas and deep-sea adapted marine bacteria, and archaeal 16S rRNAs related to that of a planktonic marine archaeon were identified. The sequences of the amplified pressure-regulated clusters were more similar to those of deep-sea barophilic bacteria than those of barotolerant bacteria. These results suggest that deep-sea adapted barophilic bacteria, planktonic marine archaea, and some of the world's most widespread bacteria (the genus Pseudomonas) coexist on the world's deepest sea-bottom.

Base Sequence↗

PubMed1997

A denitrifying bacterium from the deep sea at 11,000-m depth.

The denitrifying bacterium strain MT-1 was isolated from the mud of the Mariana Trench. The optimal temperature and pressure for growth of this bacterium were found to be 30 degrees C and 0.1 MPa, respectively. However, it showed greater tolerance to low temperature (4 degrees C) and high hydrostatic pressure (50 MPa) as compared with denitrifiers obtained from land. From the results, it can be said that this organism is adapted to the environment of the deep sea. Strain MT-1 was shown to belong to the genus Pseudomonas by analysis of its 16S rDNA. The cytochrome contents of the bacterium were similar to those of Ps. stutzeri in spectrophotometric studies.

Cytochromes↗

PubMed1997

Increase of heat-shock protein and induction of gamma/delta T cells in peritoneal exudate of mice after injection of live Fusobacterium nucleatum.

Fusobacterium nucleatum and Actinobacillus actinomycetemcomitans are Gram-negative rod periodontal pathogens. The peritoneal cavity of Institute of Cancer Research (ICR) mice was used as the local infection model. In vivo production of heat-shock proteins (hsp) was studied by injection of 1/10 minimum lethal dose (MLD) of each live bacteria into mice. Heat-shock proteins 70 and 60 were examined in the extract of peritoneal exudate cells (PEC) from mice injected intraperitoneally with either F. nucleatum or A. actinomycetemcomitans by using sodium dodecylsulphate-polyacrylamide gel electrophoresis and immunoblotting analysis. Although hsp are present in PEC without injection of the bacteria, both hsp increased and reached a peak on day 3 after F. nucleatum injection but not after A. actinomycetemcomitans. Kinetic study of gamma/delta cells in PEC after injection of bacteria showed that the increase of gamma/delta T cells was observed only in the PEC from mice injected with F. nucleatum but not A. actinomycetemcomitans. The gamma/delta T cells in PEC were either CD3+ and CD4+ or CD3+ and CD8+. The differential cell count of PEC suggested that gamma/delta T-cell induction is related to the expansion of the macrophage population. The phagocytic and chemiluminescence responses of macrophages against the same bacteria were compared after intensive immunization with live F. nucleatum and A. actinomycetemcomitans. Elevations of chemiluminescence response and phagocytic function by immunization were observed in the macrophages of mice immunized with F. nucleatum. These results suggest the sequential appearance of hsp, gamma/delta T cells and macrophage activation after fusobacterial infection.

Actinobacillus Infections↗