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T Kusakabe

Publications and source records attributed to T Kusakabe.

At least 145 records · Page 8Linked to original sources
PubMed1994

Localization of immunoreactive neuropeptides in the kidney of the bullfrog, Rana catesbeiana, by immunofluorescence.

Indirect double immunofluorescence labelling for demonstrating nine neuropeptides in the kidney of the bullfrog, Rana catesbeiana, revealed for the first time the occurrence, distribution, and coexistence of certain neuropeptides in the kidney of the submammalian vertebrates. Substance P, neuropeptide Y, and calcitonin gene-related peptide were localized in nerve fibers distributed along the afferent arterioles connected with the glomeruli, and along the capillary network between uriniferous tubules. Neuropeptide Y and calcitonin gene-related peptide immunoreactive fibers were more numerous than substance P immunoreactive fibers. In these two regions, about one half of the neuropeptide Y or calcitonin gene-related peptide fibers contained substance P. No immunoreactivity of vasoactive intestinal polypeptide, somatostatin, FMRFamide, or leucine- and methionine-enkephalins was detected in the bullfrog kidney.

Animals↗
PubMed1994

Coexistence of substance P, neuropeptide Y, VIP, and CGRP in the nerve fibers of the carotid labyrinth of the bullfrog, Rana catesbeiana: a double-labelling immunofluorescence study in combination with alternate consecutive sections.

Double immunohistochemical staining with rhodamine- and fluorescein isothiocyanate (FITC)-conjugated antisera revealed the coexistence of substance P (SP) and neuropeptide Y (NPY), and SP and calcitonin gene-related peptide (CGRP) in most nerve fibers in the intervascular stroma of the carotid labyrinth of the bullfrog, Rana catesbeiana, although there were a few fibers which showed only SP- or NPY-immunoreactivity. Approximately one third of SP-immunoreactive fibers also showed coexistence with vasoactive intestinal polypeptide (VIP)-immunoreactivity, and a few fibers contained VIP without SP. The combination of the double immunofluorescence technique and alternate consecutive sections further demonstrated the possible coexistence of SP, VIP, NPY, and CGRP. This coexistence of four different peptides in the same nerve fibers was proved by the following two evident facts: 1) some SP fibers which demonstrated coexistence with NPY-immunoreactivity were assumed to be continuous with those showing VIP-immunoreactivity, and 2) almost all of the SP fibers showed coexistence with CGRP-immunoreactivity. By this reasoning, nearly one third of SP fibers may demonstrate coexistence with NPY-, VIP-, and CGRP-immunoreactivities. These multiple peptides might be involved in vascular regulatory function, which is a possible function of the amphibian carotid labyrinth.

Animals↗
PubMed1994

Human aldolase C: characterization of the recombinant enzyme expressed in Escherichia coli.

To study the structure/function relationship and enzymatic properties of human aldolase C, we have constructed an Escherichia coli expression plasmid, pHAC11, for the isozyme. E. coli cells carrying this plasmid produced enzymatically active human aldolase C. The kcat and Km values for fructose-1,6-bisphosphate (Fru-1,6-P2) and fructose-1-phosphate (Fru-1-P) of the recombinant enzyme were found to be similar to those of authentic aldolase C from human brain. The Fru-1,6-P2/Fru-1-P activity ratio of the recombinant enzyme is approximately 13.5, which is comparable to that of the recombinant rat aldolase C, but is slightly higher than those of rat brain and hepatoma aldolases C. The substitution of Ser for the carboxyl-terminal Tyr (Tyr-363) of the recombinant enzyme caused a marked decrease in that of Fru-1,6-P2, with little change in that of Fru-1-P. The activity ratio changed from 13.5 for the normal enzyme to 3.8 for the engineered enzyme. Human aldolase C was found to form tetrameric hybrids with aldolase B in vivo when these enzymes were coexpressed in E. coli cells.

Base Sequence↗
PubMed1994

Human aldolase B: liver-specific properties of the isozyme depend on type B isozyme group-specific sequences.

A series of chimeric enzymes between two human aldolases A, B or C were constructed to identify the molecular regions responsible for isozyme-specific functions. Chimeras constructed between aldolases A and B were AB34 (an AB chimera connected at position 34), ABA34-306 and ABA212-306 (the ABA chimeras). Those between aldolases B and C are BC243, BC263 and BC306 (the BC chimeras connected at positions as indicated), as well as CB55, CB243, CB263 and CB306 (the CB chimeras connected at positions as indicated), CBC55-263 (a CBC chimera), and BCB55-193, BCB55-306, BCB79-193 and BCB79-306 (the BCB chimeric enzymes). Through the analysis of the properties of these chimeras, it was found that for aldolase B, isozyme B group-specific sequences (IGSs)-1 and -4 were required for exerting type B-specific functions, while the IGSs-2 and -3 enhanced, in collaboration with the IGS-1, the catalytic activity of aldolase B. In addition, the alpha/beta-barrel and the restricted stretches, which were not specified but occupied two distinct regions spanning the amino acid positions 108-137 (designated connector 1) and 243-306 (designated connector 2), were found to be indispensable for showing full catalytic activity of aldolase B.

Amino Acid Sequence↗
PubMed1994

Silent cerebral infarction associated with coronary artery disease.

To investigate the relationship of coronary artery disease and silent cerebral infarction, 50 patients who underwent coronary arteriography and cranial magnetic resonance imaging were studied. The patients were divided into three groups. The incidence of silent cerebral infarction (chiefly lacunar infarction) was significantly higher in patients with old myocardial infarction and in those with angina pectoris than in the control group (80, 78 and 29%, respectively, p < 0.05). Silent cerebral infarction is considered to be a risk factor for symptomatic cerebrovascular disease, so more attention should be focussed on the prevention of stroke in patients with coronary artery disease.

Aged↗
PubMed1994

Distribution of substance P-containing and catecholaminergic nerve fibers in the rabbit carotid body: an immunohistochemical study in combination with catecholamine fluorescent histochemistry.

The distribution of substance P (SP)-immunoreactive nerve fibers in the rabbit carotid body was studied in combination with catecholamine autofluorescence images of sections where SP immunoreactivity was confirmed. Immunoreactivity for SP was found in nerve fibers distributed in the parenchyma of the carotid body. No glomus cells with SP immunoreactivity were observed in the carotid body. On comparing the distribution of SP-immunoreactive fibers with the catecholamine autofluorescence image in a single section, most SP fibers appeared associated with the fluorescent glomus cells, and were located around clusters of them. These results support the suggestion that SP fibers in the cat and rat carotid bodies are involved in chemosensory mechanisms. Furthermore, a survey of the present results and previous ones reported by other workers indicates that SP may be an essential neuropeptide in chemoreceptor organs in most vertebrates from amphibians on upwards evolutionally. In addition, the courses of some catecholaminergic fibers precisely agreed with those of some SP fibers. This suggests that certain sympathetic nerve fibers also contain SP.

Animals↗
PubMed1993

Conformation-selective DNA strand breaks by dynemicin: a molecular wedge into flexible regions of DNA.

We present evidence that the enediyne antitumor antibiotic dynemicin recognizes and cleaves conformationally flexible regions of DNA. This is based on specific strand breaks at mismatches, bulges, and nicks as determined by high-resolution sequencing gels. On the basis of the weak association constant of dynemicin for DNA, it is expected that these more flexible regions would be preferred sites. In addition, the DNA unwinding behavior of dynemicin and the absorption spectrum of the dynemicin-DNA complex are strongly indicative of its intercalative binding with DNA. The results allow us to propose dynemicin as a molecular wedge that binds to the DNA by intercalating into the minor-groove side of conformationally flexible regions of DNA. Presumably, DNA local flexibility is able to create an open pocket in the minor groove, permits facile intercalation of dynemicin, and then increases the chances of its DNA damaging event. Implications for the biological action of dynemicin have also been discussed.

Anthraquinones↗
PubMed1993

Immunohistochemical coexistence of calcitonin gene-related peptide and substance P in the nerve fibers of the internal gills of bullfrog (Rana catesbeiana) larvae.

A double-labelling immunofluorescence study of the internal gills of larval bullfrogs revealed coexistence of calcitonin gene-related peptide (CGRP) and substance P (SP) in the same nerve fibers in the gill tufts. More than about 95% of CGRP fibers showed coexistence of SP, although some fibers contained CGRP without SP. In the branchial muscle, all CGRP fibers demonstrated coexistence of SP. These findings suggest that both CGRP- and SP-containing fibers may use both peptides as neuromodulators of active ion transport and gill movements.

Animals↗
PubMed1993

Coexistence of substance P and calcitonin gene-related peptide in the nerve fibers of the carotid labyrinth of the bullfrog, Rana catesbeiana.

Double immunohistochemical staining with fluorescein isothiocyanate (FITC)- and rhodamine-conjugated antisera revealed the coexistence of substance P (SP) and calcitonin gene-related peptide (CGRP) in most nerve fibers in the intervascular stroma of the carotid labyrinth of the bullfrog, Rana catesbeiana. A few fibers contained SP without CGRP. The results suggest that the vascular regulatory function, which is one of the possible functions of the carotid labyrinth, may be controlled in part by the interaction of SP and CGRP.

Animals↗
PubMed1993

DNA binding and cleavage of a novel antitumor antibiotic dynemicin A: detection of binding and cleavage sites by exonuclease III digestion and alkali-induced cutting reactions.

We found here that dynemicin A effectively breaks DNA strands under alkaline pH condition. Binding of dynemicin A to double-stranded DNA clearly interrupts the digestion reaction of exonuclease III. The DNA association sites of dynemicin A correspond considerably well to its cleavage sites. Dynemicin A seems to intercalate preferentially into the relaxed region of the DNA double helix. On the other hand, the alkali-product of dynemicin A was chromatographically identified with dynemicin N, suggesting a DNA cleavage mechanism similar to the reductant- and light-induced activation systems of dynemicin A. In order to detect drug binding to the relaxation structure in the DNA duplex, the present exonuclease III-digestion-stop-sequence method is useful.

Anthraquinones↗
PubMed1993

Ultrastructure of the glomus cells in the carotid body of chronically hypoxic rats: with special reference to the similarity of amphibian glomus cells.

The ultrastructural characteristics of the glomus cells in the rat carotid body exposed to extremely long-term hypoxia (10-12 weeks) were investigated. The glomus cells could be classified into four distinct types according to the shape of dense-cored vesicles in the glomus cell cytoplasm: 1) small vesicle cells (SVCs, 50 nm in mean diameter), 2) large vesicle cells (LVCs, 80 nm in mean diameter), 3) dilated eccentric vesicle cells (EVCs, 400-800 nm in diameter), and 4) mixed vesicle cells (MVCs, large and eccentric vesicles). Many clusters of glomus cells were found to contain all four categories of cell types. The appearance of EVCs was a unique and common characteristic of glomus cells in this long-term hypoxia model. We also noted other ultrastructural features with chronic hypoxia which are characteristic of the amphibian carotid labyrinth glomus cells: 1) incomplete covering of glomus cells with the supporting cell missing over a wide area, 2) long thin cytoplasmic projections in the intervascular stroma, and 3) intimate apposition of the glomus cells and pericytes (g-p connection), endothelial cells (g-e connection), plasma cells, and fibrocytes. Because arterial PO2 is generally low in amphibia, these may be general features of hypoxic adaptation and facilitate both uptake of oxygen from blood and release of catecholamine into the blood. The g-p and g-e connections may take part in the regulation of the microcirculation in the enlarged carotid body.

Amphibians↗
PubMed1993

Mechanism of inhibitory action of capsaicin on particulate axoplasmic transport in sensory neurons in culture.

The inhibitory effect of capsaicin on axoplasmic transport in cultured dorsal root ganglion cells was analyzed by video-enhanced contrast microscopy. Capsaicin inhibited particle transports in a dose-dependent manner, irrespective of the diameter of axons. The effect of capsaicin was reversible at low concentrations. Capsaicin affected both the anterograde and retrograde transport. Large organelles were more sensitive to capsaicin than small ones in the retrograde transport. An experiment using calcium-sensitive dye, Fura 2, indicated that capsaicin raised the intraneuronal free calcium concentration preceding the inhibition of the transport. Electron microscopy revealed that microtubules and neurofilaments are disorganized and disoriented by capsaicin. We reached a conclusion that capsaicin inhibits fast axoplasmic transport of both anterograde and retrograde directions in all types of somatosensory neurons in culture by disorganizing intraaxonal cytoskeletal structures, through the elevated intracellular Ca2+ concentration.

Animals↗
PubMed1993

Distribution of FMRFamide-immunoreactive nerve fibers in the carotid labyrinth of the bullfrog, Rana catesbeiana in corresponding differential interference-contrast (Nomarski) images.

Immunoreactivities for FMRFamide and substance P (SP) in the carotid labyrinth of the bullfrog were detected using the peroxidase-antiperoxidase method, and the results compared with corresponding differential interference-contrast (Nomarski) images. Colocalization of both peptides was determined by the indirect double immunofluorescence method. Immunoreactivities for FMRFamide and SP were found in nerve fibers distributed in the intervascular stroma of the labyrinth. The FMRFamide-immunoreactive fibers were less numerous than the SP-immunoreactive fibers. In the Nomarski image, FMRFamide-fibers were recognized in relief, with most of them located near the walls of blood vessels. All FMRFamide-fibers coexisted with SP. The results suggest that FMRFamide-immunoreactive fibers are also involved in local vascular regulation of the carotid labyrinth.

Animals↗
PubMed1993

Induced-fit association between DNA and esperamicin. Importance of structural flexibility in host DNA duplex.

In this study, a series of synthetic oligonucleotide duplexes are tested as a substrate for esperamicin. The duplexes contain a typical binding sequence of esperamicin, 5'-GGA/TCC, but have different flexibilities in helix structure from each other. When cleavage activities of these oligonucleotides by esperamicin were estimated by using DNA sequencing method, a substantial increase of the cleavage at 3'-NAGG was observed with increasing the helix flexibility. This observation indicates that structural flexibility of host DNA duplex is important in an induced-fit association between esperamicin and DNA.

Aminoglycosides↗
PubMed1992

Tunicate muscle actin genes. Structure and organization as a gene cluster.

We have isolated and determined the complete nucleotide sequences of two genes, HrMA4a and HrMA2, which encode the same muscle actin protein of the tunicate Halocynthia roretzi. HrMA4a and HrMA2 contain three exons, and the genes have intron-exon splice junctions at the same positions. The 5' flanking region of HrMA4a gene contains several potential regulatory elements. A TATA box is located at -30 and a CArG box found in regulatory region of vertebrate muscle-specific genes is located at -116. Seven E-box consensus sequences (CANNTG) known as binding sites for vertebrate myogenic determination factors are found within a 500 base-pair portion of the 5' flanking region of HrMA4a gene. HrMA4a and HrMA2 are separated by 1600 bases in genomic DNA and transcribed in the same direction. In addition to these genes, we have identified three other actin genes encoding muscle-type actins. All five actin genes are located in a 30 x 10(3) base-pair region of the genome and aligned in the same direction. This is the first report of a cluster of "vertebrate-type" muscle actin genes. The consensus sequences of 5' flanking region are conserved among these five genes, suggesting that the expression of the genes is controlled coordinately. This may be advantageous for the accumulation of considerable amounts of actin proteins in rapidly developing embryos of this animal.

Actins↗
PubMed1992

Ultrastructural characteristics of glomus cells in the external carotid artery during larval development and metamorphosis in bullfrogs, Rana catesbeiana.

Electron microscopic observations of the external carotid artery in the larvae of the bullfrog, Rana catesbeiana, showed that glomus cells are present in the subendothelial stroma of the septum between the expanded region of the external carotid artery and the carotid arch. There were some differences in the ultrastructure of the glomus cells at each stage of larval development. At the early stages (stages I, III, V, X), most glomus cells were isolated and free from the covering of a supporting cell. The cytoplasm of the glomus cells contained fewer dense-cored vesicles. No synaptic junctions were observed. At the middle stages (stages XV, XX, XXI), some glomus cells showed a tendency to form small clusters. Between adjacent cells in a cluster, gap junctions were often observed. The number of dense-cored vesicles increased remarkably. Intimate apposition of the glomus and smooth muscle cells (g-s connection) was also observed. Nerve terminals containing clear vesicles were observed in synaptic contact with glomus cells at this phase. At the metamorphic climax (stages XXII-XXV), in addition to g-s connections, the glomus cells made intimate apposition to the cells around the glomus cells. The afferent synapses described in other amphibians were not encountered in this study. These findings suggest that the glomus cells at the early stages of development are nonfunctional, the vascular regulation via the g-s connection starts at the middle stages, and the chemoreception starts after metamorphosis.

Animals↗