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D Watanabe

Publications and source records attributed to D Watanabe.

At least 19 recordsLinked to original sources
PubMed2006

Significant change of alignment effect by dimer formation in the dissociative energy transfer reaction of Ar(3P2)+(N2O)n and (H2O)n.

An alignment effect in the dissociative energy transfer reaction of Ar((3)P(2))+(X(2)O)(n)(X=N,H) was directly measured using an oriented Ar((3)P(2),M(J)=2) beam. The chemiluminescence intensity of N(2)(B,(3)Pi(g)) for (N(2)O)(n) and OH(A,(2)Sigma(+)) for (H(2)O)(n) was measured as a function of the magnetic orientation field direction in the collision frame. The relative reaction cross section for each magnetic substate in the collision frame, sigma(M(J) (') ), was determined. In both the reaction systems, it is observed that the dimer formation significantly enhances the alignment effect and decreases the reactivity, especially for sigma|1| and sigma|2|. A significant contribution of rank 4 moment is recognized in the dimer reaction.

Journal Article↗
PubMed2006

Transition of mouse de novo methyltransferases expression from Dnmt3b to Dnmt3a during neural progenitor cell development.

Dnmt3a and Dnmt3b, which are known as functional de novo methyltransferases, are responsible for creating genomic methylation patterns during mammalian development. Recently, we have shown that specific expression of Dnmt3b in epiblast, embryonic ectoderm, hematopoietic progenitor cells and spermatogonia cells is followed by Dnmt3a expression (Watanabe D, Suetake I, Tada T, Tajima S (2002) Stage- and cell-specific expression of Dnmt3a and Dnmt3b during embryogenesis. Mech Dev 118:187-190; Watanabe D, Suetake I, Tajima S, Hanaoka K (2004) Expression of Dnmt3b in mouse hematopoietic progenitor cells and spermatogonia at specific stages. Gene Expr Patterns 5:43-49). In this study, we analyzed the expression of mouse de novo methyltransferases during development of the nervous systems. In the embryonic olfactory epithelium (OE), Dnmt3b was specifically expressed in Mash1 positive globose basal cells (i.e. transiently amplifying neural progenitor cells), while Dnmt3a was expressed in immature olfactory receptor neurons. Dnmt3b-positive cells were rarely observed in the adult OE, but were increased in regenerating OE with intranasal ZnSO(4) administration. Dnmt3b was also detected in the E8.5 neural plate, E10.5 spinal cord and retina cells, while Dnmt3a was expressed in postmitotic young neurons. Furthermore, Dnmt3b was specifically expressed in ES cells, while Dnmt3a was transiently expressed during neural cell differentiation of ES cells. Dnmt3b is specifically expressed in progenitor cells during hematopoiesis, spermatogenesis and neurogenesis, suggesting an important role in the initial steps of progenitor cell differentiation. Dnmt3a is expressed in postmitotic young neurons following the Dnmt3b expression. Dnmt3a may be required for the establishment of tissue-specific methylation patterns of the genome. The coordinated expression of de novo methyltransferases from Dnmt3b to Dnmt3a suggests conserved mechanisms of de novo methylation of the genome and different functions for Dnmt3b and Dnmt3a during progenitor cell development.

Animals↗
PubMed2006

Steric effect in the energy transfer reaction of Ar(3P2)+N2.

Steric effect for N2(C,3Piu) formation in the energy transfer reaction of Ar(3P2)+N2 was directly measured by using an oriented Ar(3P2,MJ=2) beam at a collision energy of 0.06 eV. The N2(C,3Piu) chemiluminescence intensity was measured as a function of the magnetic orientation field direction in the collision frame. A significant alignment effect on the energy transfer probability was observed. The relative reactivity for each magnetic substate in the collision frame sigma|MJ'|was determined to be sigma|2|:sigma|1|:sigma(0)=0.50:0.60:1.00. It is suggested that the observed steric effect is primarily due to the favorable configuration of the 3p orbital for the efficient overlap with the 2sigma(u) molecular orbital of N(2).

Journal Article↗
PubMed2006

Analysis of gene mutations in four cases of dermatofibrosarcoma protuberans.

Fusion of the collagen type I alpha 1 (COL1A1) gene with the platelet-derived growth factor B-chain (PDGFB) gene has been described in dermatofibrosarcoma protuberans (DFSP). Various exons of the COL1A1 gene have been shown to be involved in the fusion with exon 2 of the PDGFB gene. We examined the breakpoints of the COL1A1 gene using the tumour specimens from four patients with DFSP. The COL1A1-PDGFB fusion transcripts were detected from the cultured tumour cells by reverse transcriptase polymerase chain reaction. Sequence analysis revealed that the ends of exons 23, 25, 26 and 36 in the COL1A1 gene were fused with the start of exon 2 in the PDGFB. This study identified three novel COL1A1 breakpoints: exons 23, 26 and 36 of the COL1A1 gene. In one case, the tumour was composed of two areas that differed in cytological atypia, cellularity and mitotic activity, indicating the dedifferentiation of the tumour. In tumour cells from two different areas the same aberrant fusion transcripts were identified. These results suggest that the dedifferentiation of tumour cells has nothing to do with the specific breakpoints of the COL1A1 gene, but depends on other unknown factors.

Adult↗
PubMed2001

Increased sensitivity to cocaine by cholinergic cell ablation in nucleus accumbens.

Chronic exposure to cocaine causes long-lasting behavioral changes associated with cocaine reinforcement and addiction. An important neural substrate for cocaine addiction is the nucleus accumbens (NAc), which receives dopaminergic input from the ventral tegmental area. Although the neural circuit of the NAc is controlled by several other neurotransmitters, their involvement in cocaine addiction remains elusive. In this investigation, we ablated cholinergic interneurons from the adult NAc with immunotoxin-mediated cell targeting and examined the role of acetylcholine transmitter in adaptive behavioral changes associated with cocaine reinforcement and addiction. Acute exposure to cocaine induced abnormal rotation in unilaterally cholinergic cell-eliminated mice. This abnormal turning was enhanced by repeated exposure of cocaine. In bilaterally cholinergic cell-eliminated mice, chronic cocaine administration induced a prominent and progressive increase in locomotor activity. Moreover, these mice showed robust conditioned place preference with a lower dose of cocaine, compared with wild-type littermates. This investigation demonstrates that acetylcholine in the NAc plays a key role in both acute and chronic actions of cocaine.

Acetylcholine↗
PubMed2001

Effect of the deletion of US2 and US3 from herpes simplex virus type 2 on immune responses in the murine vagina following intravaginal infection.

We investigated the effects of US2 and US3 deficiencies of herpes simplex virus type 2 (HSV-2) on host immunity in a murine model of genital herpes infection. Viral clearance from the vaginal mucosa was more rapid in mice infected with a US3-deficient mutant L1BR1 as compared with a wild-type 186 or YY2 (US2-deficient mutant) infection, although there was no significant difference among them in initial growth in the early stage of infection. Flow cytometric studies revealed that the number of vaginal mononuclear cells in L1BR1-infected mice was significantly greater than that in 186- or YY2-infected mice. Dendritic cells, macrophages and T cells were induced more rapidly and in greater numbers within the vaginas of L1BR1-infected mice. Moreover, the levels of IL-12 and IFN-gamma increased in L1BR1-infected mice over levels in 186-infected mice. These results indicate that a US3 deficiency alters the induction of the host immune response; therefore, the inactivation of US3 may be a promising strategy in the development of novel vaccines for genital herpes.

Administration, Intravaginal↗
PubMed2001

Four tyrosine residues in phospholipase C-gamma 2, identified as Btk-dependent phosphorylation sites, are required for B cell antigen receptor-coupled calcium signaling.

Activation of phospholipase C-gamma2 (PLCgamma2) is the critical step in B cell antigen receptor (BCR)-coupled calcium signaling. Although genetic dissection experiments on B cells have demonstrated that Bruton's tyrosine kinase (Btk) and Syk are required for activating PLCgamma2, the exact activation mechanism of PLCgamma2 by these kinases has not been established. We identify the tyrosine residues 753, 759, 1197, and 1217 in rat PLCgamma2 as Btk-dependent phosphorylation sites by using an in vitro kinase assay. To evaluate the role of these tyrosine residues in phosphorylation-dependent activation of PLCgamma2, PLCgamma2-deficient DT40 cells were reconstituted with a series of mutant PLCgamma2s in which the phenylalanine was substituted for tyrosine. Substitution of all four tyrosine residues almost completely eliminated the BCR-induced PLCgamma2 phosphorylation, indicating that these residues include the major phosphorylation sites upon BCR engagement. Cells expressing PLCgamma2 with a single substitution exhibited some extent of reduction in calcium mobilization, whereas those expressing quadruple mutant PLCgamma2 showed greatly reduced calcium response. These findings indicate that the phosphorylations of the tyrosine residues 753, 759, 1197, and 1217, which have been identified as Btk-dependent phosphorylation sites in vitro, coordinately contribute to BCR-induced activation of PLCgamma2.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed2001

BLNK mediates Syk-dependent Btk activation.

Btk is a critical molecule in B cell antigen receptor (BCR)-coupled signaling, and its activity is regulated by Lyn and Syk. Although the molecular mechanism of Lyn-dependent Btk activation has been investigated, that of Syk-dependent Btk activation has remained unidentified. We have demonstrated that BLNK mediates Syk-dependent Btk activation. In a reconstitution cell system, coexpression of BLNK allows Syk to phosphorylate Btk on its tyrosine 551, leading to the enhancement of Btk activity. This phosphorylation depends on the interaction of Btk and BLNK by means of the Btk-Src homology 2 domain. The existence of such an activation mechanism is supported by the observation that the BCR-induced Btk phosphorylation and activation are significantly reduced in BLNK-deficient B cells as well as in Syk-deficient B cells. Although previous observations have identified the function of BLNK as the linker that integrates the action of Btk and Syk into downstream effectors such as phospholipase Cgamma2, our present study indicates another function of BLNK that connects the activity of Syk to that of Btk.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Yeast Lrg1p acts as a specialized RhoGAP regulating 1,3-beta-glucan synthesis.

Selection of an extragenic suppressor of fks1-1154 Deltafks2, mutations in the catalytic subunits of yeast 1,3-beta-glucan synthase (GS) conferring temperature-sensitivity, led to the LRG1 gene, which was originally identified as a LIM-RhoGAP homologous gene. Mutations in the LRG1 gene restore impaired 1,3-beta-glucan synthesis in the fks1-1154 Deltafks2 mutant as well as that in rho1-2, a temperature-sensitive mutant of Rho-type GTPase that functions as a regulatory subunit of GS. Two-hybrid analyses of Lrg1p, which contains a sequence conserved among Rho GTPase-activating proteins (GAPs), revealed its specific interactions with the active form of Rho1p. Among eight potential yeast RhoGAPs, Lrg1p is the only member that negatively regulates GS activity: mutations in the rest of GAPs, including bem2, Deltabem3, Deltasac7, Deltabag7, Deltarga1, Deltarga2 and Deltargd1, do not suppress impairment of 1,3-beta-glucan synthesis. Analyses of Mpk1p phosphorylation revealed the inability of Lrg1p to regulate the Pkc1p-MAP kinase cascade, a distinct Rho1p-regulating signalling pathway known to be affected by the GAPs, Bem2p and Sac7p. Thus, different groups of Rho1p GAPs control the activity of different Rho1p-effector proteins.

DNA-Binding Proteins↗
PubMed2001

The US2 gene product of herpes simplex virus type 2 interacts with cytokeratin 18.

In order to clarify the biological role of US2 gene product of herpes simplex virus type 2 (HSV-2), a HeLa cDNA library was screened in the yeast two-hybrid system using US2 protein as bait, and several interacting proteins were identified, including cytokeratin 18. US2 protein was co-immunoprecipitated with cytokeratin 18 from HSV-2 infected cell lysates. Analysis of infected orA431 cells by immunofluorescence showed that US2 protein gave filamentous or dot-like cytoplasmic staining pattern, and that it co-localized with cytokeratin 18. When US2 protein was expressed alone, it co-localized with cytokeratin 18. To define the domain interacting with cytokeratin 18, deletion mutant proteins were constructed and cells transfected with mutants were analyzed by indirect immunofluorescence. These results suggest that the N-terminal half of the US2 protein, especially the region containing amino acids 42-77, is important for interaction with cytokeratin 18.

Animals↗
PubMed2001

A key role of starburst amacrine cells in originating retinal directional selectivity and optokinetic eye movement.

The directional selectivity of retinal ganglion cell responses represents a primitive pattern recognition that operates within a retinal neural circuit. The cellular origin and mechanism of directional selectivity were investigated by selectively eliminating retinal starburst amacrine cells, using immunotoxin-mediated cell targeting techniques. Starburst cell ablation in the adult retina abolished not only directional selectivity of ganglion cell responses but also an optokinetic eye reflex derived by stimulus movement. Starburst cells therefore serve as the key element that discriminates the direction of stimulus movement through integrative synaptic transmission and play a pivotal role in information processing that stabilizes image motion.

Acetylcholine↗
PubMed2001

Identification of the acid phosphatase (acpA) gene homologues in pathogenic and non-pathogenic Burkholderia spp. facilitates TnphoA mutagenesis.

Burkholderia pseudomallei and Burkholderia mallei are pathogens responsible for disease in both humans and animals. Burkholderia thailandensis, while phylogenetically similar, is considered avirulent in comparison. These three species exhibit phosphatase activity when grown on media containing chromogenic substrates such as 5-bromo-4-chloro-3-indolyl phosphate (XP). Tn5-OT182 mutagenesis has been utilized to isolate mutants of B. pseudomallei and B. thailandensis unable to hydrolyse XP. Sequence analysis of these mutants revealed an ORF of 1734 nucleotides demonstrating a high degree of homology to the acpA gene product of Francisella tularensis. PCR primers were designed based on the B. pseudomallei acpA gene sequence and were used to amplify an acpA homologue from B. mallei. The predicted amino acid sequence of B. pseudomallei AcpA differed from those of the predicted B. thailandensis AcpA and B. mallei AcpA by 15 and 3 amino acids, respectively. Allelic exchange was used to construct DeltaacpA mutants in each of these Burkholderia spp. These mutants were shown to be devoid of phosphatase activity and have subsequently allowed for the implementation of phoA fusion transposon mutagenesis systems. Two such systems have been successfully utilized in Burkholderia spp. for the identification of several genes encoding exported proteins.

Acid Phosphatase↗
PubMed2001

Proliferation stage-dependent expression of DNA methyltransferase (Dnmt1) in mouse small intestine.

In cultured cells, the maintenance-type DNA methyltransferase (Dnmt1) is highly expressed during the proliferation stage. In the present study, we detected significant expression of Dnmt1 protein in the nuclear fraction of mouse small intestine. From its mobility in SDS polyacrylamide gel electrophoresis and the specific antibodies against the somatic cell-type Dnmt1, Dnmt1 was determined as a somatic cell type. Immunofluorescence study revealed that the Dnmt1 was highly expressed in the proliferating stem cells in crypts, and was localized in the nuclei. The present results indicate that the expression of Dnmt1 in vivo is also under the control of cell proliferation as in cultured cells.

Animals↗
PubMed2001

The nature of the delocalized cations in azulenic bacteriorhodopsin analogs.

Depending on the size and shape of their azulenic chromophores, azulenic bacteriorhodopsin (bR) pigment analogs can exist as either an initial pigment P1, a more red-shifted final pigment P2 or an equilibrium mixture of both. The absorption spectra of red-shifted bR analogs exhibit characteristic narrow-band shapes similar to charge fully delocalized cyanine-like dyes. Therefore, all such red-shifted pigments are believed to be highly delocalized, bond-equalized carbocations. We have determined structural requirements that facilitate their formation. To describe fully the red-shift potentials of these retinal analogs, we have introduced a new parameter-percent red-shift (PRS). A large PRS value not only reflects the extent of red-shift, but is also suggestive of extensive delocalization of the positive charge. Relevance of these findings in consideration of the possibility of forming stable O-intermediates is presented. The postulated resonance hybrid-like structures for different cations of the positively charged protonated Schiff base chromophores are in fact structurally distinct species, equilibrating in response to local perturbations within the supramolecular protein environment.

Bacteriorhodopsins↗
PubMed2001

Acute phase response in toxicity studies. II. Findings in beagle dogs injected with endotoxin or subjected to surgical operation.

Occurrence of characteristic transient changes in WBC counts and fibrinogen values in beagle dogs subjected to single-dose toxicity studies was pointed out in the previous survey (Hoshiya et al., 2001). These changes were thought to belong to the category of "Acute Phase Response (APR)". The purpose of the present study is to compare the APR found in the single-dose toxicity studies surveyed in our previous report with those experimentally produced by intravenous injection of 1 microgram/kg endotoxin (Experiment 1), and surgical treatment (Experiment 2) (intravenous indwelling catheterization). The animals used in Experiment 2 were intravenously injected with 1 microgram/kg endotoxin 2 weeks after the operation (Experiment 3), and the results were compared with those of Experiments 1 and 2. Each experimental group consisted of 5 dogs, and clinical, hematological and blood chemical examinations were performed. Essentially the same changes were observed in response to the intravenous injection with endotoxin and the surgical operation for intravenous indwelling catheterization in beagle dogs. The most remarkable changes common to both treatments were transient increases in the fibrinogen values and WBC counts during the 2 days from Day 1 to Day 2 of the treatment. These changes were preceded by decreases in WBC counts and fibrinogen in Experiments 1 and 3. Increased erythrocyte sedimentation rates were recorded in parallel with the increase in fibrinogen. The results obtained in the present study were similar to those found in dogs treated with various xenobiotic substances in our laboratory. These changes due to different causes were thought to belong to the category of "APR" with the same biological significance as a non-specific defense mechanism.

Acute-Phase Reaction↗
PubMed2001

Acute phase response in toxicity studies. I. Survey of beagle dogs subjected to single-dose toxicity studies.

In the field of routine single-dose toxicity studies, we occasionally meet with transient leukocytosis associated with an increase in fibrinogen in beagle dogs within a few days after treatment with the test article. Only a little is known, however, about the toxicological significance of these changes. However, these changes were thought to belong to the category of "Acute Phase Response, APR," which has been known for a long time in connection with injury, trauma or infection. Aiming at proper understanding of these experiences, we surveyed 25 single-dose toxicity studies (7 intravenous bolus, 5 intravenous infusion, 12 oral and 1 subcutaneous treatment, hereafter referred to simply as i.v. bolus, i.v. infusion, oral and s.c.) in beagle dogs, provided with data from hematological examinations. We set the following criteria as a positive response in the present survey: increases of 50% or more in either or both WBC or fibrinogen compared to the predosing value, transiently from Day 1 to Day 3 of the study. Among 25 studies surveyed, about 1/2 of the studies exhibited increases of 50% or more in either or both fibrinogen or WBC counts compared to the predosing values showing dose-dependency transiently on Day 1 or Day 2. These changes were remarkable after intravenous application. Oral application produced similar effects, although the incidence and severity were low compared to the i.v. routes. Regarding blood chemical and hematological changes other than changes in fibrinogen and WBC counts, there were no essential differences between the groups of studies with and without the changes in fibrinogen and WBC counts. These changes were thought to be characteristic and to have occurred as incidents unrelated to other changes. The reported changes seen in single-dose toxicity studies may belong to the category of APR as the non-specific mechanism of living bodies as stated by Burns et al. (1996).

Acute-Phase Reaction↗
PubMed2001

[A clear cell type meningioma in the upper eyelid ascertained by immunohistochemical examination].

BACKGROUND: We encountered a rare case of clear cell meningioma in the upper eyelid. CASE: A 66-year-old man presented with a slow by progressive, well-defined, soft globelar tumor in the left upper eyelid. The tumor showed homogeneous isodensity and was contrasty in a computed tomograph. Histologically, oval-shaped cells with clear cytoplasm had both streamed and whorl configurations, but showed neither psammomas nor calcification. Immunohistochemically, vimentin, epithelial membrane antigen, and protein S-100 were expressed by the tumor cells. CONCLUSIONS: Eyelid meningioma may originate from embryonal remains of the arachnoid in the sheath around the trigeminal nerve, and may vary histologically. Immunohistochemical examination helps to define cases of uncommon subtypes of meningioma.

Aged↗