Biomedical subjects

N Kikuchi

Publications and source records attributed to N Kikuchi.

At least 37 records · Page 2Linked to original sources

PubMed2001

Morphometrical study of the arterial perforators of the deep inferior epigastric perforator flap.

Although abdominal perforator flaps based on a cutaneous branch of the deep inferior epigastric artery (DIEP flaps) have many advantages, preparing these flaps is technically difficult and requires great skill, especially as the portion of the artery running under the anterior rectus abdominis sheath must be operated upon "blind". To allow easier preparation and elevation of a DIEP flap pedicle, we propose that the arterial perforator should: 1) be more than 1.0 mm large; 2) run a straight intramuscular course, parallel to the rectus abdominis m. fibers, with no large muscular branches; and 3) have only a short portion running immediately under the anterior rectus abdominis sheath. We examined 329 perforators (more than 0.5 mm in diameter at the anterior sheath) in 66 rectus abdominis mm. from 33 cadavers among them: 1) 52 "large" perforators were over 1.0 mm in diameter; 2) 107 "suitable" perforators ran parallel to the muscle fibers without giving off large muscular branches; and 3) 35 "ideal" perforators combined these characteristics. The ideal perforators were usually located in the mid-abdominal region, 10-30 mm lateral to the umbilicus. The suitable perforators were usually present, often in combination with the ideal perforator(s), in a restricted area 20 mm cranial and 40-50 mm lateral to the umbilicus. We classified the course and ramification pattern of the deep inferior epigastric a. into six patterns, depending on whether the anastomosis was sited in the medial or lateral branch and the level at which the branches originated.

Aged↗

PubMed2001

Comparative analyses of the distribution of various transposable elements in Pyricularia and their activity during and after the sexual cycle.

We examined the distribution and activity of six transposable elements found in the blast fungus, Pyricularia spp. Sixty-eight isolates from various gramineous plants were used for the survey, and the elements were plotted on a dendrogram constructed on the basis of their rDNA-ITS2 sequences. MGR586 and Pot2 (Class II elements), Mg-SINE (SINE-like element) and MGR583 (LINE-like retrotransposon) were widely distributed among the Pyricularia isolates, suggesting that they are old elements which arose in, or invaded, the Pyricularia population at very early stages in its evolution. By contrast, the distribution of the LTR-retrotransposons MAGGY and Grasshopper was limited or sporadic, suggesting that they are relatively new elements which recently invaded the Pyricularia population by means of horizontal transfer events. The activity of these elements was evaluated by Southern analysis in progenies derived from a cross between a Setaria isolate and a Triticum isolate. Many new MAGGY signals were observed, which were absent in the parental isolates, at various stages of the sexual cycle and following vegetative growth. In contrast, the other elements yielded few, if any, such signals. Analysis of the sequences flanking the new MAGGY insertions revealed that they were each associated with a 5-bp target-site duplication at both ends of the insertion. These data suggested that MAGGY was the most active of the elements tested for transposition in Pyricularia.

Blotting, Southern↗

PubMed2001

The Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes (JSGIT): initial aims and impact of the family history of type 1 diabetes mellitus in Japanese children.

The Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes (JSGIT) was established in July 1994 with the chief aim to improve the quality of therapy for type 1 diabetes in children, an entity far less common in Japan than in Europe. We proposed four initial research topics: (i) to determine the current status of medical care and glycemic control in Japanese children with type 1 diabetes mellitus; (ii) to standardize the measurement of hemoglobin A1c; (iii) to establish a registry of a large cohort of patients in order to enable prospective studies to improve the quality of therapy for children with type 1 diabetes in Japan; and (iv) to enable participants of the JSGIT to hold a workshop twice annually. We registered a total of 736 patients from 45 hospitals throughout Japan. Intervention via insulin treatment was instituted after 2 yr for those patients whose hemoglobin A1c level was more than 8.1%. The proportion of patients receiving multiple insulin injections increased after intervention; however, average hemoglobin A1c in females remained significantly higher than in males. We identified two forms of diabetes in Japanese children: a rapidly progressive form and a more slowly progressive form. There was a significantly higher prevalence of a family history of diabetes in first-degree relatives in the slowly progressive form. These preliminary findings are the result of the first collaborative study of childhood diabetes in Japan.

Journal Article↗

PubMed2001

Isolation and characterization of three genes paralogous to mouse Ring3.

Syntenic chromosomal areas share paralogous genes which are believed to have been generated by repeated duplication of an ancestral gene. The human RING3 gene is known to have paralogous relationships with the ORFX, BRDT, and HUNK1 genes. In addition to the mouse Ring3 cDNA clones previously reported, we isolated mouse Orfx, Brdt, and Hunk1 cDNA clones using mouse testis RNA. Among these four paralogous genes, structure and expression profiles were compared. The proteins encoded by these genes exhibited similar amino acid sequences including two conserved bromodomains. While the Ring3, Orfx, and Hunk1 genes were ubiquitously expressed in various tissues of adult mouse, the Ring3, Orfx, and Brdt genes produced testis-specific transcripts and the Hunk1 gene produced a striated muscle-specific transcript. The diversification of expression patterns of Ring3-related genes during evolution may reflect nucleotide variations in regulatory elements associated with ubiquitous or tissue-specific gene expression.

Animals↗

PubMed2001

Inhibitory action of leptin on early follicular growth differs in immature and adult female mice.

In order to investigate the action of leptin on early follicular growth, preantral follicles, 95-115 microm in diameter were mechanically isolated from the ovaries of BDF1 hybrid immature (11-day-old) and adult (8-wk-old) mice, and cultured for 4 days in vitro. Follicular growth was assessed by daily changes in follicular diameter and by the amount of estradiol and immunoreactive (IR)-inhibin released into the culture medium at Day 4. Preantral follicles from immature mice showed a significant development in follicular growth as a result of stimulation by GH (1 mIU/ml), insulin-like growth factor (IGF)-I (100 ng/ml) + FSH (100 mIU/ml), and GH (1 mIU/ml) + FSH (100 mIU/ml). Although leptin at concentrations of 1-1000 ng/ml did not have any significant effect on follicular growth stimulated by IGF-I or GH, it significantly inhibited follicular growth in a dose-related manner when follicles were stimulated by IGF-I + FSH and GH + FSH, respectively, suggesting that leptin attenuated the additive effect of FSH. On the other hand, preantral follicles from adult mice were cultured in the presence of FSH, and FSH-dependent follicular growth was inhibited by leptin in a dose-related manner. Because FSH stimulates cAMP production, we investigated the involvement of cAMP in the inhibitory mechanisms of leptin. Preantral follicles from immature and adult mice were cultured in the presence of either 8-Br-cAMP or forskolin. Both 8-Br-cAMP and forskolin significantly increased follicular diameter and hormone secretion in both immature and adult mice. However, 8-Br-cAMP and forskolin-stimulated follicle growth and hormone secretion were significantly inhibited in immature mice by coadministration of leptin, whereas growth of preantral follicles from adult mice was not inhibited by addition of leptin to cultures. These results indicate that leptin causes an inhibitory effect on the early follicular development of both immature and adult mice, but the inhibitory mechanisms of leptin are different.

Aging↗

PubMed2001

Effect of adrenal and ovarian androgens on type 4 follicles unresponsive to FSH in immature mice.

The present study investigates the physiological significance of dehydroepiandrosterone, dehydroepiandrosterone sulfate, T, androstenedione (Delta(4)), dihydrotestosterone (DHT), estrone (E1), and E2 on recombinant human FSH- (rhFSH) resistant type 4 follicles obtained from immature mice. Type 4 follicles of a diameter of 100-120 microm with one or two granulosa cell layers around the oocyte and an intact basal lamina with theca cells were isolated from the ovaries of 11-d-old BDF-1 mice and cultured with medium alone (control) or with dehydroepiandrosterone, dehydroepiandrosterone sulfate, T, Delta(4), DHT, E1, or E2 at concentrations ranging from 1 x 10(-11) to 1 x 10(-7) M for 4 d. We examined the mean diameters of type 4 follicles, levels of immunoreactive (IR)-inhibin, and E2 and progesterone in the culture media on day 4. In addition, we evaluated follicular cell proliferation by immunofluorescence staining with 5-bromo-2'-deoxyuridine. All tested androgens significantly increased the diameter of type 4 follicles in a dose-dependent manner without the production of IR-inhibin and E2. The nuclei of granulosa cells in type 4 follicles cultured with all tested androgens exhibited intense 5-bromo-2'-deoxyuridine-positive staining, compared with those of controls. In contrast, neither E1 nor E2 had any stimulatory effects. The stimulatory effects of T, Delta(4), or DHT were inhibited by an AR antagonist in a dose-related fashion but not by an aromatase inhibitor. Furthermore, all tested androgens had a synergistic effect with rhFSH on follicular growth and the production of IR-inhibin and E2. These results demonstrated that neither adrenal nor ovarian androgens are arteriogenic but that they stimulate type 4 follicles unresponsive to rhFSH and augment the responsiveness of these follicles to rhFSH.

Adrenal Glands↗

PubMed2000

The Saccharomyces cerevisiae RuvB-like protein, Tih2p, is required for cell cycle progression and RNA polymerase II-directed transcription.

Two highly conserved RuvB-like putative DNA helicases, p47/TIP49b and p50/TIP49a, have been identified in the eukaryotes. Here, we study the function of Saccharomyces cerevisiae TIH2, which corresponds to mammalian p47/TIP49b. Tih2p is required for vegetative cell growth and localizes in the nucleus. Immunoprecipitation analysis revealed that Tih2p tightly interacts with Tih1p, the counterpart of mammalian p50/TIP49a, which has been shown to interact with the TATA-binding protein and the RNA polymerase II holoenzyme complex. Furthermore, the mutational study of the Walker A motif, which is required for nucleotide binding and hydrolysis, showed that this motif plays indispensable roles in the function of Tih2p. When a temperature-sensitive tih2 mutant, tih2-160, was incubated at the nonpermissive temperature, cells were rapidly arrested in the G(1) phase. Northern blot analysis revealed that Tih2p is required for transcription of G(1) cyclin and of several ribosomal protein genes. The similarities between the mutant phenotypes of tih2-160 and those of taf145 mutants suggest a role for TIH2 in the regulation of RNA polymerase II-directed transcription.

Bacterial Proteins↗

PubMed2000

Morphological assessment of the effect of growth hormone on preantral follicles from 11-day-old mice in an in vitro culture system.

The present study was carried out to verify that the cells attached to the outside of the basement membrane of mechanically isolated follicles are theca cells and to evaluate the effect of growth hormone (GH) on these cells. Preantral follicles, 100-140 micrometer in diameter, were mechanically isolated from 11-day-old BDF1 hybrid immature mice, divided randomly into two groups, and cultured in vitro. One group was treated with 0.1% collagenase immediately after mechanical isolation in an attempt to remove theca cells attached to the outside of the basement membrane. The other group was untreated. Morphological examination revealed that 86.1% of mechanically isolated follicles before collagenase treatment had at least one theca cell around the basement membrane on the single section. However, after collagenase treatment no theca cells remained on the basement membrane of the follicles. Androstenedione secretion as a result of stimulation by 100 ng/ml hCG was significantly higher in the culture medium of the follicles with theca cells than in those of collagenase-pretreated follicles (p < 0.0001), indicating that the cells attached to the outside of the basement membrane were actually functional theca cells, not interstitial cells. To elucidate the effect of GH on theca cells, preantral follicles cultured in the presence of 1.0 mIU/ml GH were morphologically examined. Preantral follicles mechanically isolated from immature mice showed significant proliferation of not only granulosa cells but also theca cells in the presence of GH. In particular, theca cells, which remained dotted on the basement membrane in a small number just after isolation, proliferated and finally formed complete layers after the culture with GH. This is the first report that GH induced the proliferation of theca cells to form morphologically complete layers around the preantral follicle from 11-day-old mice.

Androstenedione↗

PubMed2000

Coronary artery bypass grafting with gastroepiploic artery composite graft.

BACKGROUND: To achieve better results after coronary artery bypass grafting (CABG), arterial conduits are the first choice in multiple CABG for younger patients. We present here the early results of CABG with gastroepiploic artery (GEA) composite graft with free radial artery (RA) to revascularize right coronary artery or left circumflex artery in addition to internal thoracic artery to left anterior descending artery. METHODS: Between July 1997 and June 1998, 13 patients received CABG with GEA (larger caliber than 2.0 mm) composite graft. We have assessed the early results. RESULTS: There was no postoperative death or major morbidity. Postoperative angiogram was performed in 11 patients and all conduits were patent. Postoperative exercise stress test was done in 13 cases and showed no ischemia. CONCLUSIONS: Multiple CABG with arterial conduit can be performed by this procedure. The free RA functioned from secondary branches derived from proximal GEA. In conclusion, this procedure seems to be safe and effective, and both long-term patency and better quality of life may be expected.

Abdominal Muscles↗

PubMed2000

Effects of recombinant human FSH (rhFSH), urinary purified FSH (uFSH), and hMG on small preantral follicles and tertiary follicles from normal adult and androgen-sterilized female mice.

OBJECTIVE: To examine the stage-specific follicular response to recombinant human FSH (rhFSH), urinary FSH (uFSH), and hMG preparations. SETTING: In vitro follicle culture. INTERVENTION(S): Small preantral and tertiary follicles isolated from adult normal BDF-1 mice and androgen-sterilized mice were cultured with rhFSH, uFSH, and hMG for 4 days. MAIN OUTCOME MEASURE(S): Follicular diameter. Immunoreactive inhibin, E2, and progesterone concentrations in cultured medium. RESULT(S): The minimal effective dose of rhFSH, uFSH, and hMG for the follicular growth of small preantral follicles from normal mice was 10 mIU/mL, 1 mIU/mL, and 0.1 mIU/mL, respectively. For tertiary follicles from normal mice, the minimal effective dose of rhFSH, uFSH, and hMG was 10 mIU/mL, 10 mIU/mL, and 1 mIU/mL, respectively. The minimal effective dose of hMG for the follicular growth of small preantral follicles from androgen-sterilized mice was 0.01 mIU/mL, and that of rhFSH and uFSH on tertiary follicles from androgen-sterilized mice was 1 mIU/mL and 10 mIU/mL, respectively. No significant increase was found in the follicular diameter of the tertiary follicles from androgen-sterilized mice as a result of stimulation by hMG, but an hMG dose of >10 mIU/mL produced a significant increase in progesterone secretion. CONCLUSION(S): Human menopausal gonadotropin preparation acts detrimentally on follicles from androgen-sterilized mice by increasing the sensitivity of small preantral follicles to FSH and by inducing the luteinization of tertiary follicles.

Age Factors↗

PubMed2000

Pathogenic factors of glucose intolerance in obese Japanese adolescents with type 2 diabetes.

We attempted to identify the pathogenic factors involved in the progression to type 2 diabetes in obese Japanese adolescents. Subjects included 18 nondiabetic obese adolescents, 12 obese adolescents with type 2 diabetes on diet therapy, 10 obese adolescents with type 2 diabetes manifesting ketosis at onset or with a history of treatment with hypoglycemic agents, and 26 non-obese adolescent control subjects. The first-phase insulin response (FPIR), glucose disappearance constant (Kg), glucose effectiveness (Sg), and insulin sensitivity (S(I)) were obtained using an insulin-modified frequently sampled intravenous glucose tolerance test (FSIGT) and a minimal model analysis. The disposition index (DI, by FPIR x S(I)) was determined to assess any endogenous insulin effect. The results showed that Kg was decreased significantly (P = .0006) with the progression to severe diabetes in the obese groups. Although S(I) and Sg did not differ significantly among the 3 obese groups, both parameters were significantly lower in each obese group versus the non-obese controls. As a result of the significant decrease in FPIR (P < .0001), the DI decreased (P = .0006) with the progression to severe diabetes in the obese groups. In conclusion, an early manifestation of type 2 diabetes with occasional ketosis at onset may result from beta-cell dysfunction to glucose stimulation. This finding is demonstrated by the relatively low FPIR to decreased S(I) in obese Japanese adolescents, as well as the low Sg as a synergic role in glucose intolerance. The present findings from a Japanese population for pathogenic factors aside from obesity may help us to gain a better understanding of the progression to adolescent, early-onset, obese type 2 diabetes and its severity.

Adolescent↗

PubMed2000

Partial left ventriculectomy, ventriculoplasty or valvular surgery for idiopathic dilated cardiomyopathy - the role of intra-operative echocardiography.

BACKGROUND: The partial left ventriculectomy (PLV) is known to work in some patients with dilated cardiomyopathy (DCM), although this procedure does not work well in all patients and the operative mortality is higher than the other cardiac surgeries. In addition to PLV, left ventriculoplasty to exclude antero-septal wall or valvular surgery without left ventricle (LV) surgery can be also effective in patients with DCM. To improve the surgical results for dilated cardiomyopathy, we introduced echo-guided volume reduction test and evaluated the surgical procedures and the results on the surgery for DCM. METHODS: Between December 1996 and July 1999, 56 patients with DCM (50 with idiopathic DCM, six with dilated hypertrophic cardiomyopathy) were surgically treated. Under the standard cardiopulmonary bypass, left ventricular motion was determined with color kinesis of echocardiogram and the lesion of akinetic wall was removed or excluded. RESULTS: After the initial PLV in 18 patients (initial group), operative procedures were selected in 21 with PLV, five with LV plasty, or 12 with valve surgery without LV surgery according to the findings of the LV wall motion by intraoperative echogram (select group). There were six hospital deaths and late follow-up deaths within 1 year in initial group, however, the mortality decreased significantly after the selection of the operative procedures; three hospital deaths and two late deaths in the select-group (P<0.05). Significant decrease of left ventricular diameter, the LV ejection fraction and endosystolic volume index were demonstrated after the LV surgery. The survival rate improved significantly after the selection of the operative procedures; 14 months survival rates was 50.0% in initial group and 73.1% in select group (P<0.05). CONCLUSION: Operative mortality decreased and late follow-up results improved after the selection of operative procedures according to the intraoperative volume reduction test.

Adolescent↗

PubMed2000

Nontransplant cardiac surgery for end-stage cardiomyopathy.

OBJECTIVE: To treat end-stage cardiomyopathy, we evaluated endoventricular circular patch plasty, partial left ventriculectomy, and valvular reconstruction alone in our 2-year experience. METHODS: Among 86 patients with heart failure evaluated between December 1996 and February 1999, 33 patients with ischemic cardiomyopathy (25 men and 8 women; mean age 61 +/- 7.8 years; New York Heart Association class 3.5 +/- 0.5) were treated with endoventricular circular patch plasty combined with coronary bypass grafting (84%) and mitral reconstruction (36%). The other 53 patients with nonischemic cardiomyopathy (45 men and 8 women; mean age 48 +/- 14.3 years, New York Heart Association class 3.7 +/- 0.5), were treated by left ventricular reduction by partial left ventriculectomy (n = 37) or patch plasty (n = 3) and valve reconstruction alone (n = 13). The first 24 patients (group I) underwent ventriculectomy with or without valve reconstruction; the more recent 29 patients (group II) underwent left ventricular reduction (n = 16) or valve reconstruction alone (n = 13) on the basis of the intraoperative echocardiographic evaluation to observe changes of wall motion and thickness during cardiopulmonary bypass. RESULTS: Ischemic Group: Hospital mortality in elective (n = 26) and emergency (n = 7) operations was 4% and 43%, and 3 patients died in the late postoperative period. Mean New York Heart Association class and ejection fraction improved from 3.5 +/- 0.5 to 1.5 +/- 0.7 and from 23% +/- 7.7% to 36% +/- 8.6%, respectively. Left ventricular end-diastolic and end-systolic volume indexes decreased from 162 +/- 46 mL/m(2) to 110 +/- 39 mL/m(2) and from 130 +/- 47 mL/m(2) to 70 +/- 32 mL/m(2), respectively. Nonischemic Group: In 40 patients with left ventricular reduction, hospital mortality in elective (n = 33) and emergency (n = 7) operations was 6% and 86%, and 5 patients died in the late postoperative period. Mean New York Heart Association class and ejection fraction improved from 3.7 +/- 0.5 to 1.7 +/- 0.6 and from 18% +/- 6.4% to 31% +/- 5.9%. Left ventricular end-diastolic and end-systolic volume indexes decreased from 203 +/- 45 mL/m(2) to 110 +/- 37 mL/m(2) and from 164 +/- 40 mL/m(2) to 79 +/- 33 mL/m(2), respectively. In 13 patients undergoing valve reconstruction alone (12 mitral with or without tricuspid and 1 tricuspid plus left ventricular assist device), hospital mortality in elective (n = 9) and emergency (n = 4) operations was 0% and 50% with no late deaths. Mean New York Heart Association class and ejection fraction improved from 3.6 +/- 0.5 to 2.0 +/- 0.5 and from 22% +/- 6.0% to 30% +/- 14.5%, respectively. Mean left ventricular end-diastolic and end-systolic volume indexes decreased from 170 +/- 34 mL/m(2) to 150 +/- 50 mL/m(2) and from 140 +/- 38 mL/m(2) to 104 +/- 40 mL/m(2), respectively. Overall mortality decreased from 50% in group I to 10% in group II. The survival estimates at 2 years were 77% (confidence limits 57%-88%) in the ischemic group and 63% (confidence limits 47%-75%) in the nonischemic group (no significant difference). The analysis of our data showed that the factors influencing the surgical results for dilated cardiomyopathy were presence of severe mitral regurgitation, preoperative New York Heart Association functional class IV with emergency operation, and operative procedures with randomly performed partial left ventriculectomy without an intraoperative echo test. CONCLUSION: Endoventricular circular patch plasty, partial left ventriculectomy, and solo valve reconstruction can be performed with an acceptably low risk as elective operations. The selection of operative procedures in idiopathic dilated cardiomyopathy and avoidance of emergency surgery improved operative mortality and morbidity. Among patients who survived at least 1 year, there were no late deaths up to 30 months' follow-up.

Adolescent↗

PubMed2000

Umbilical reconstruction with an inverted C-V flap.

We have created a method for umbilical reconstruction with satisfactory results. The C-V flap developed for nipple reconstruction was used in an inverted fashion. The inverted C-V flap can produce a satisfactory reconstruction of umbilical structures, especially the ring.

Child↗

PubMed2000

Effect of estrogen and progesterone on gene expression of growth regulatory molecules and proto-oncogene in vascular smooth muscle cells.

We examined influences of estrogen and progestogen on gene expression of the growth regulatory molecules: platelet-derived growth factor (PDGF), interleukin-1 (IL-1), interleukin-6 (IL-6) and proto-oncogene c-myc in vascular smooth muscle cells (VSMC) by reverse transcription-polymerase chain reaction (RT-PCR) and Southern-blotting. VSMC were exposed to estrone-sulfate (E1-S) and medroxyprogesterone acetate (MPA) to induce differentiation. E1-S inhibited the expression of PDGF-A chain, IL-1, IL-6 and c-myc mRNA, whereas MPA had no effect. Inhibition by E1-S was not affected by treatment combined with MPA. These findings suggest that estrogen modulates these growth regulatory molecules and c-myc gene expression in VSMC but not progestogen. We concluded that estrogen may have a direct atheroprotective effect through inhibition of growth regulatory factors.

Arteriosclerosis↗

PubMed1999

Similarity relations of DNA and RNA polymerases investigated by the principal component analysis of amino acid sequences.

The principal component analysis based on the physicochemical properties of amino acid residues is applied to DNA and RNA polymerases to assign the sequence motifs for the polymerization activities of these proteins. After the reconfirmation of the sequence motifs of families A and B of DNA polymerases indicated previously, it elucidates the sequence motifs for the polymerization activity of DNA polymerase III (family C) by the similarity to the polymerization center of multimeric DNA dependent RNA polymerases. This identification proceeds to clarify the sequence motifs for polymerization activities of primases; eukaryotic and archaebacterial primases carry motifs similar to those of family C, while the motifs of eubacterial primase fall into the category of the motifs in family B DNA polymerases such as alpha, delta, epsilon and II. This finding means that DNA dependent RNA polymerases are also divided into groups corresponding to three families, A, B and C, because the monomeric DNA dependent RNA polymerases in phages are reconfirmed to carry sequence motifs similar to those of family A DNA polymerases. Furthermore, the three families of polymerization motifs are found to fall within the variation range of polymerization motifs displayed by many RNA dependent RNA polymerases, suggesting a close evolutionary relation between them. The sequence motifs for polymerization activities of reverse transcriptase and telomerase seem to be the intermediate between family A DNA polymerase and some RNA dependent RNA polymerases, e.g., from Leviviridae. On the contrary, the sequence fragments similar to the nucleotidyltransferase superfamily including DNA polymerase beta are not found in any RNA dependent RNA polymerase, suggesting their other lineage of polymerization motifs.

Amino Acid Sequence↗

PubMed1999

Molecular shape and ATP binding activity of rat p50, a putative mammalian homologue of RuvB DNA helicase.

Based on partial amino acid sequences of p50 purified from a high-salt buffer extract of a rat liver nuclear matrix fraction, p50 cDNA was cloned and sequenced, and its amino acid sequence was predicted. The sequence contained helicase motifs, and showed homology with RuvB DNA helicase of Thermus thermophilus and an open reading frame for an unknown 50.5 k protein of Saccharomyces cerevisiae. p50 was expressed as a GST-fusion protein and antiserum against the protein was generated. p50 was localized to the nuclear matrix by cell fractionation and immunoblotting. p50 bound to ATP-Sepharose beads. Ultracentrifugation and gel filtration analyses showed that p50 in rat liver and Xenopus egg mitotic extracts exists as large complexes corresponding to 697 k and 447 k, respectively. A 50 k protein reactive with p50 antibodies was detected not only in rat liver nuclei, but also in a Xenopus egg cytoplasm fraction and a S. cerevisiae extract. This suggests that this putative DNA helicase is present in a wide variety of species ranging from yeast to mammals.

ATPases Associated with Diverse Cellular Activitie↗

PubMed1999

Phylogenetic relationships of 38 taxa of the genus Staphylococcus based on 16S rRNA gene sequence analysis.

The nucleotide sequences of the 16S rRNA gene (rDNA) in 38 taxa of the genus Staphylococcus were compared phylogenetically. Based on phylogenetic tree analysis, staphylococcal species were divided into 12 cluster groups. These cluster groups were in very good agreement with species groups determined by DNA-DNA reassociation studies. These genealogical classifications were consistent with the results of the production of coagulase or oxidase and with resistance to novobiocin. These suggest that the phylogenetic relationship of the genus Staphylococcus is accurately represented by the results obtained from the sequence analysis of 16S rDNA.

DNA, Bacterial↗