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T Fukatsu

Publications and source records attributed to T Fukatsu.

At least 19 recordsLinked to original sources
PubMed2006

Role of host nutrition in symbiont regulation: impact of dietary nitrogen on proliferation of obligate and facultative bacterial endosymbionts of the pea aphid Acyrthosiphon pisum.

The impact of host nutrition on symbiont regulation in the pea aphid Acyrthosiphon pisum was investigated. The population density of the obligate symbiont Buchnera aphidicola positively correlated with dietary nitrogen levels. In contrast, the population density of the facultative symbiont Serratia symbiotica increased in aphids reared on low-nitrogen diets, indicating distinct regulatory mechanisms in the same insect host.

Animals↗
PubMed2005

Rickettsia infection in natural leech populations.

Field-collected specimens of glossiphoniid leeches, Torix tagoi, Torix tukubana, Hemiclepsis marginata, and Hemiclepsis japonica, were surveyed for Rickettsia infection by using a diagnostic PCR assay. Rickettsia was detected in 96% (69/72) of T. tagoi, 83% (24/29) of T. tukubana, 29% (33/113) of H. marginata, and 0% (0/30) of H. japonica. The frequencies of Rickettsia infection were stably maintained in different seasons. In H. marginata and T. tukubana, distant local populations exhibited remarkably different frequencies of Rickettsia infection. Eggs carried by infected females of T. tagoi and H. marginata were all Rickettsia-positive, indicating nearly 100% vertical transmission. Analysis of 16S rDNA sequences revealed that phylogenetic relationship of the leech-associated Rickettsia reflected the specific and populational divisions of the host leeches. However, circumstantial lines of evidence strongly suggested that horizontal transmission of Rickettsia must have occurred in the ancestors of these leeches. In T. tagoi and T. tukubana, infected individuals were remarkably larger in size than uninfected individuals, wheras in H. marginata, infected and uninfected individuals were almost comparable in size. This study first provides information on ecological aspects of leech-bone endocellular bacteria of the genus Rickettsia. On the basis of these data, we discuss possible mechanisms whereby Rickettsia infection is maintained in natural populations of these leeches in the freshwater ecosystem.

Animals↗
PubMed2005

Characterization of a facultative endosymbiotic bacterium of the pea aphid Acyrthosiphon pisum.

The pea aphid U-type symbiont (PAUS) was investigated to characterize its microbiological properties. Fluorescence in situ hybridization (FISH) and electron microscopy revealed that PAUS was a rod-shaped bacterium found in three different locations in the body of the pea aphid Acyrthosiphon pisum: sheath cells, secondary mycetocytes, and hemolymph. Artificial transfer experiments revealed that PAUS could establish stable infection and vertical transmission when introduced into uninfected pea aphids. When 28 aphid species collected in Japan were subjected to a diagnostic PCR assay, four species of the subfamily Aphidinae (Aphis citricola, Aphis nerii, Macrosiphum avenae, and Uroleucon giganteus) and a species of the subfamily Pemphiginae (Colopha kansugei) were identified to be PAUS-positive. The sporadic incidences of PAUS infection without reflecting the aphid phylogeny can be best explained by occasional horizontal transfers of the symbiont across aphid lineages.

Animals↗
PubMed2002

Maintenance of soldier-producing aphids on an artificial diet.

In our efforts to understand the biology of soldier-producing aphids, we attempted to maintain them in the laboratory using a chemically defined artificial diet. The ability of 16 species from the subfamilies Eriosomatinae and Hormaphidinae, most of which are soldier-producing species, to survive on the artificial diet was examined. Some species neither fed nor grew on the diet, whereas other species accepted the diet, grew to some extent, and managed to produce a small number of short-lived offspring. Although they performed poorly on the diet in general, aphid performance was correlated with the stage in the life cycle and the developmental stadium in that aphids of the gall generation tended to accept the diet and survive on it, whereas aphids of the non-gall generation did not. Also, old insects tended to perform better on the diet than young nymphs. Notably, only one species, Tuberaphis styraci, a gall-forming aphid that produces 2nd instar sterile soldier, showed good performance on the diet. Insects collected from galls (generation G0) survived on the diet, grew well, and produced many progeny. Three successive generations (G1, G2 and G3) were produced on the diet. Developmental period, adult body size, and age of first reproduction were almost constant through G0, G1 and G2 whereas fecundity, adult longevity and daily offspring production declined as the generations proceeded. These results are comparable to previous studies in which pest aphids have been maintained on similar artificial diets for several generations. Therefore, it is suggested that the artificial-diet rearing system will provide a useful tool to investigate various biological aspects of the soldier-producing eusocial aphid, T. styraci.

Journal Article↗
PubMed2001

Genetically distinct populations in an Asian soldier-producing aphid, Pseudoregma bambucicola (Homoptera: Aphididae), identified by DNA fingerprinting and molecular phylogenetic analysis.

To estimate genetic structure of a soldier-producing aphid, Pseudoregma bambucicola, samples from natural populations throughout southeastern Asia were analyzed by a DNA fingerprinting technique. We unexpectedly found that P. bambucicola comprises two geographic groups, the northern group and the southern group, which are genetically distinct from each other but morphologically almost indistinguishable. Molecular phylogenetic and statistical analyses based on mitochondrial ribosomal DNA sequences demonstrated that the northern and southern groups of P. bambucicola are not closely related but constitute distinct lineages in the genus Pseudoregma. Detailed morphological reexamination revealed that the two groups could be distinguished by the number of setae on the 8th abdominal tergite of 1st instar nymphs and soldiers. From these results, it was suggested that P. bambucicola should be divided into two species. The northern group from Japan, Taiwan, Hong Kong, and northern Vietnam retains the name P. bambucicola, whereas we suggest that the name P. carolinensis (R. Takahashi, 1941, Tenthredo 3, 208-220) should be used for the southern group from Thailand, Malay Peninsula, Java, Irian Jaya, and Micronesia. The morphological resemblance between P. bambucicola and P. carolinensis might be due to shared ancestral characters of the genus Pseudoregma.

Animals↗
PubMed2001

Evolutionary dynamics of multiple group I introns in nuclear ribosomal RNA genes of endoparasitic fungi of the genus Cordyceps.

A large number of group I introns were discovered in coding regions of small and large subunits of nuclear ribosomal RNA genes (SSU rDNA and LSU rDNA) in ascomycetous fungi of the genus CORDYCEPS: From 28 representatives of the genus, we identified in total 69 group I introns which were inserted at any of four specific sites in SSU rDNA and four specific sites in LSU rDNA. These group I introns reached sizes of up to 510 bp, occurred in up to eight sites in the same organism, and belonged to either subgroup IB3 or subgroup IC1 based on their sequence and structure. Introns inserted at the same site were closely related to each other among Cordyceps fungi, whereas introns inserted at different sites were phylogenetically distinct even in the same species. Mapped on the host phylogeny, the group I introns were generally not restricted to a particular lineage, but, rather, widely and sporadically distributed among distinct lineages. When the phylogenetic relationships of introns inserted at the same site were compared with the phylogeny of their hosts, the topologies were generally significantly congruent to each other. From these results, the evolutionary dynamics of multiple group I introns in Cordyceps fungi was inferred as follows: (1) most of the group I introns were already present at the eight sites in SSU and LSU rDNAs of the ancestor of the genus Cordyceps; (2) the introns have principally been immobile and vertically transmitted throughout speciation and diversification of Cordyceps fungi, which resulted in the phylogenetic congruence between the introns at the same site and their hosts; (3) in the course of vertical transmission, the introns have repeatedly been lost in a number of lineages independently, which has led to the present sporadic phylogenetic distribution of the introns; and (4) a few acquisitions of new introns, presumably through horizontal transmission, were identified in the evolutionary history of the genus Cordyceps, while no transpositions were detected. Losses of group I introns in SSU rDNA have occurred at least 27 times in the evolutionary course of the 28 Cordyceps members.

Base Sequence↗
PubMed2001

Secondary intracellular symbiotic bacteria in aphids of the genus Yamatocallis (Homoptera: Aphididae: Drepanosiphinae).

A novel secondary intracellular symbiotic bacterium from aphids of the genus Yamatocallis (subfamily Drepanosiphinae) was characterized by using molecular phylogenetic analysis, in situ hybridization, and diagnostic PCR detection. In the aphid tissues, this bacterium (tentatively designated YSMS [Yamatocallis secondary mycetocyte symbiont]) was found specifically in large cells surrounded by primary mycetocytes harboring Buchnera cells. Of nine drepanosiphine aphids examined, YSMS was detected in only two species of the same genus, Yamatocallis tokyoensis and Yamatocallis hirayamae. In natural populations of these aphids, YSMS was present in 100% of the individuals. Phylogenetic analysis based on 16S ribosomal DNA (rDNA) sequences demonstrated that YSMS of Y. tokyoensis and Y. hirayamae constitute a distinct and isolated clade in the gamma subdivision of the class Proteobacteria. No 16S rDNA sequences of secondary endosymbionts characterized so far from other aphids showed phylogenetic affinity to YSMS. Based on these results, I suggest that YSMS was acquired by an ancestor of the genus Yamatocallis and has been conserved throughout the evolution of the lineage. By using the nucleotide substitution rate for 16S rDNA of Buchnera spp., the time of acquisition of YSMS was estimated to be about 13 to 26 million years ago, in the Miocene epoch of the Tertiary period.

Animals↗
PubMed2001

Spiroplasma symbiont of the pea aphid, Acyrthosiphon pisum (Insecta: Homoptera).

From a laboratory strain of the pea aphid, Acyrthosiphon pisum, we discovered a previously unknown facultative endosymbiotic bacterium. Molecular phylogenetic analysis based on 16S ribosomal DNA revealed that the bacterium is a member of the genus Spiroplasma. The Spiroplasma organism showed stable vertical transmission through successive generations of the host. Injection of hemolymph from infected insects into uninfected insects established a stable infection in the recipients. The Spiroplasma symbiont exhibited negative effects on growth, reproduction, and longevity of the host, particularly in older adults. Of 58 clonal strains of A. pisum established from natural populations in central Japan, 4 strains possessed the Spiroplasma organism.

Animals↗
PubMed2001

[No relation between angiotensin-converting enzyme (ACE) inhibitor-induced cough and ACE gene polymorphism, plasma bradykinin, substance P and ACE inhibitor concentration in Japanese patients].

Persistent dry cough is well known as the most common side-effect of angiotensin-converting enzyme (ACE) inhibitors. We examined the relationship between a cough and ACE gene polymorphism, plasma bradykinin (BK), substance P (SP) and ACE inhibitor concentrations in patients with hypertension or chronic nephritis. First, ACE genotyping was carried out in 96 patients, 42 with coughs and 54 without coughs, which had been treated with various kinds of ACE inhibitors. However, no significant difference in the ACE genotypes was observed between the two groups. Second, the plasma concentrations of BK, SP and ACE inhibitor were measured in 12 patients, which were treated with trandolapril at a daily dose of 1 mg for 4-33 weeks. In 3 patients, the cough was induced during the trandolapril therapy, while it was induced not in 9 patients. The plasma levels of BK and SP did not significantly change after trandolapril administration in the patients with and without coughs. Between the two groups, there were no significant differences in the plasma levels of BK and SP either before or after the trandolapril therapy. Also the plasma concentrations of trandolapril and trandolaprilat, the active metabolite of trandolapril, did not significantly differ between the two groups. These results suggest that there is no significant relationship between the ACE inhibitor-induced cough and ACE gene polymorphism, plasma BK, SP and ACE inhibitor concentrations in patients with hypertension or chronic nephritis.

Aged↗
PubMed2001

[Rupture of renal pelvis due to urolithiasis: report of two cases].

Two cases of renal pelvis rupture caused by urolithiasis are reported. The first case was in a 62-year-old male who had left flank pain. Urological examination including drip infusion pyelography (DIP) and abdominal computed tomography (CT) revealed a spontaneous rupture of the left renal pelvis. The rupture was assumed to have been caused by a small ureteral stone. The stone passed spontaneously, and the extravasation disappeared with conservative therapy. The second case was in a 84-year-old male who was admitted with high fever. Urological examination including DIP and abdominal CT showed a suspected rupture of the left renal pelvis due to a renal stone at the ureteropelvic junction. Percutaneous nephrostomy was performed and antegrade pyelography showed extravasation from the left renal pelvis. Extravasation disappeared on the 12th postoperative day. Extracorporeal shock wave lithotripsy was performed three times. The renal stone was completely discharged and the nephrostomy tube was removed successfully.

Aged↗
PubMed2001

[Alkaline phosphatase].

High levels of alkaline phosphatase activity are characteristic of bone disease with increased osteoblastic activity, hepatobiliary disease with partial or complete biliary obstruction and transient hyperphosphatasemia in children. A gamma-glutamyl transpeptidase is often useful to differentiate whether an elevated alkaline phosphatase originates in the bones or the liver. A normal gamma-glutamyl transpeptidase suggests bone origin. A serum alkaline phosphatase isozyme pattern by electrophoresis is also necessary to differentiate various pathological states.

Alkaline Phosphatase↗
PubMed2000

Interkingdom host jumping underground: phylogenetic analysis of entomoparasitic fungi of the genus cordyceps.

Most members of the ascomycetous genus Cordyceps are endoparasitic fungi of insects and other arthropods, but about 20 of the 300 described species are parasitic to hart's truffles, Elaphomyces spp. In order to understand the evolution of host specificity and the process of interkingdom host jumping in Cordyceps, we investigated the phylogenetic relationships of 22 representatives, including 4 truffle parasites and 18 insect parasites, based on nuclear and mitochondrial rDNA sequences. Five monophyletic groups were identified in both nuclear and mitochondrial phylogenies. In three of the five clades, the members utilized hosts from the same insect group, suggesting that the endoparasite-host connections have been conserved to some extent. On the other hand, it was also shown that major host shifts between distantly related insects must have occurred repeatedly. Notably, phylogenetic analyses strongly suggested that parasites of hart's truffles originated from parasites of cicada nymphs during the evolution of the CORDYCEPS: The common habitats of cicada nymphs and hart's truffles, deep underground and associated with tree roots, suggest that the interkingdom host jumping from Animalia to Fungi might have been promoted by the overlapping ecological niche of the unrelated hosts. This finding provides an impressive case of a drastic host shift in favor of the host habitat hypothesis.

Animals↗
PubMed2000

Endosymbiotic microbiota of the bamboo pseudococcid Antonina crawii (Insecta, Homoptera).

We characterized the intracellular symbiotic microbiota of the bamboo pseudococcid Antonina crawii by performing a molecular phylogenetic analysis in combination with in situ hybridization. Almost the entire length of the bacterial 16S rRNA gene was amplified and cloned from A. crawii whole DNA. Restriction fragment length polymorphism analysis revealed that the clones obtained included three distinct types of sequences. Nucleotide sequences of the three types were determined and subjected to a molecular phylogenetic analysis. The first sequence was a member of the gamma subdivision of the division Proteobacteria (gamma-Proteobacteria) to which no sequences in the database were closely related, although the sequences of endosymbionts of other homopterans, such as psyllids and aphids, were distantly related. The second sequence was a beta-Proteobacteria sequence and formed a monophyletic group with the sequences of endosymbionts from other pseudococcids. The third sequence exhibited a high level of similarity to sequences of Spiroplasma spp. from ladybird beetles and a tick. Localization of the endosymbionts was determined by using tissue sections of A. crawii and in situ hybridization with specific oligonucleotide probes. The gamma- and beta-Proteobacteria symbionts were packed in the cytoplasm of the same mycetocytes (or bacteriocytes) and formed a large mycetome (or bacteriome) in the abdomen. The spiroplasma symbionts were also present intracellularly in various tissues at a low density. We observed that the anterior poles of developing eggs in the ovaries were infected by the gamma- and beta-Proteobacteria symbionts in a systematic way, which ensured vertical transmission. Five representative pseudococcids were examined by performing diagnostic PCR experiments with specific primers; the beta-Proteobacteria symbiont was detected in all five pseudococcids, the gamma-Proteobacteria symbiont was found in three, and the spiroplasma symbiont was detected only in A. crawii.

Animals↗
PubMed2000

The secondary endosymbiotic bacterium of the pea aphid Acyrthosiphon pisum (Insecta: homoptera).

The secondary intracellular symbiotic bacterium (S-symbiont) of the pea aphid Acyrthosiphon pisum was investigated to determine its prevalence among strains, its phylogenetic position, its localization in the host insect, its ultrastructure, and the cytology of the endosymbiotic system. A total of 14 aphid strains were examined, and the S-symbiont was detected in 4 Japanese strains by diagnostic PCR. Two types of eubacterial 16S ribosomal DNA sequences were identified in disymbiotic strains; one of these types was obtained from the primary symbiont Buchnera sp., and the other was obtained from the S-symbiont. In situ hybridization and electron microscopy revealed that the S-symbiont was localized not only in the sheath cells but also in a novel type of cells, the secondary mycetocytes (S-mycetocytes), which have not been found previously in A. pisum. The size and shape of the S-symbiont cells were different when we compared the symbionts in the sheath cells and the symbionts in the S-mycetocytes, indicating that the S-symbiont is pleomorphic under different endosymbiotic conditions. Light microscopy, electron microscopy, and diagnostic PCR revealed unequivocally that the hemocoel is also a normal location for the S-symbiont. Occasional disordered localization of S-symbionts was also observed in adult aphids, suggesting that there has been imperfect host-symbiont coadaptation over the short history of coevolution of these organisms.

Animals↗
PubMed2000

[Two cases of abdominal masses caused by foreign bodies which were preoperatively diagnosed as urachal abscess].

A 61-year-old man and a 59-year-old woman were referred to our hospital because of lower abdominal pain and discomfort, pollakisuria and a lower abdominal mass. In both patients, radiological studies and cystoscopy caused us to suspect a urachal abscess. We performed operations transperitoneally. In the male patient, fish bones were detected between the mass and ileum. A partial cystectomy was performed on the female patient, and the histological diagnosis was Sparganosis mansoni. In both cases, it was very difficult to make a correct diagnosis before the operations, but surgical treatment was successfully performed.

Abdominal Abscess↗
PubMed1999

Value of percutaneous transhepatic portography before hepatectomy for hilar cholangiocarcinoma.

BACKGROUND: The diagnostic value of percutaneous transhepatic portography (PTP) for assessing cancer invasion of the portal bifurcation in patients with hilar cholangiocarcinoma has not been studied previously. METHODS: From April 1977 to March 1998 combined hepatobiliary and portal vein resection was performed in 45 patients. In 25 patients, PTP was carried out before operation and the resected portal bifurcation was examined histologically. Correlation between portographic and microscopic findings at the portal bifurcation was studied retrospectively. RESULTS: Portographic and microscopic findings were classified into three groups (type A, B or C, and grade 0, I or II respectively) according to the findings at the portal bifurcation. There was a significant correlation between the portographic type and degree of cancer invasion (P = 0.0001). In seven of the eight patients with type A portograms, there was no microscopic cancer invasion of the portal bifurcation. In 15 of the 17 patients with type B or C portograms, cancer invasion was found microscopically. All patients with microscopic grade II invasion had type C portograms. CONCLUSION: PTP can be used to evaluate cancer invasion of the portal bifurcation with sufficient reliability for preoperative staging of hilar cholangiocarcinoma.

Adult↗
PubMed1999

Acetone preservation: a practical technique for molecular analysis.

In attempts to establish a convenient and reliable method for field collection and archival preservation of insects and their endosymbiotic microorganisms for molecular analysis, acetone, ethanol, and other organic solvents were tested for DNA preservability of the pea aphid Acyrthosiphon pisum and its intracellular symbiotic bacterium Buchnera sp. After 6 months' storage, not only the band of high-molecular-size DNA but also the bands of rRNA were well preserved in acetone, ethanol, 2-propanol, diethyl ether and ethyl acetate. Polymerase chain reaction (PCR) assays confirmed that the DNA of both the insects and their symbionts was well preserved in these solvents. In contrast, methanol and chloroform showed poor DNA preservability. When water-containing series of acetone and ethanol were examined for DNA preservability, acetone was apparently more robust against water contamination than ethanol. Considering that most biological materials contain high amounts of water, acetone may be a more recommendable preservative for DNA analysis than ethanol which has been widely used for this purpose. The DNA of various insects could be preserved in acetone at room temperature in good condition for several years. In addition to the DNA of the host insects, the DNA of their endosymbionts, including Buchnera and other mycetocyte symbionts, Wolbachia, and gut bacteria, was amplified by PCR after several years of acetone storage. The RNA and protein of the pea aphid and its endosymbiont were also preserved for several years in acetone. After 2 years' storage in acetone, proteins of A. pisum could be analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting, and the endosymbiotic bacteria were successfully detected by immunohistochemistry and in situ hybridization on the tissue sections.

Acetone↗