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Biomedical subjects

S Murakami

Publications and source records attributed to S Murakami.

At least 19 recordsLinked to original sources
PubMed1997

Novel genes encoding 2-aminophenol 1,6-dioxygenase from Pseudomonas species AP-3 growing on 2-aminophenol and catalytic properties of the purified enzyme.

2-Aminophenol 1,6-dioxygenase was purified from the cell extracts of Pseudomonas sp. AP-3 grown on 2-aminophenol. The product from 2-aminophenol by catalysis of the purified enzyme was identified as 2-aminomuconic 6-semialdehyde by gas chromatographic and mass spectrometric analyses. The molecular mass of the native enzyme was 140 kDa based on gel filtration. It was dissociated into molecular mass subunits of 32 (alpha-subunit) and 40 kDa (beta-subunit) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicating that the dioxygenase was a heterotetramer of alpha2beta2. The genes coding for the alpha- and beta-subunits of the enzyme were cloned and sequenced. Open reading frames of the genes (amnA and amnB) were 816 and 918 base pairs in length, respectively. The amino acid sequences predicted from the open reading frames of amnA and amnB corresponded to the NH2-terminal amino acid sequences of the alpha-subunit (AmnA) and beta-subunit (AmnB), respectively. The deduced amino acid sequences of AmnB showed identities to some extent with HpaD (25.4%) and HpcB (24.4%) that are homoprotocatechuate 2,3-dioxygenases from Escherichia coli W and C, respectively, belonging to class III in the extradiol dioxygenases. On the other hand, AmnA had identity (23.3%) with only AmnB among the enzymes examined.

Amino Acid Sequence↗
PubMed1997

Inhaled nitric oxide attenuates reperfusion injury in non-heartbeating-donor lung transplantation. Paris-Sud University Lung Transplantation Group.

BACKGROUND: Non-heartbeating-donor (NHBD) lung transplantation could help reduce the current organ shortage. Polymorphonuclear neutrophil (PMN) activation plays a pivotal role in ischemia-reperfusion injury (I-R), and can be inhibited by nitric oxide (NO). We hypothesized that inhaled NO might be beneficial in NHBD lung transplantation. METHODS: The effect of inhaled NO on PMNs was studied by measuring in vivo PMN lung sequestration (myeloperoxidase activity) and adhesion of recipient circulating PMNs to cultured pulmonary artery endothelial cells (PAECs) in vitro. Pigs were randomly assigned to an NO or a control group (n=9 each). In the NO group, cadavers and recipients were ventilated with oxygen and 30 parts per million of NO. After 3 hr of postmortem in situ warm ischemia and 2 hr of cold ischemia, left allotransplantation was performed. The right pulmonary artery was ligated, and hemodynamic and gas exchange data were recorded hourly for 9 hr. Recipient PMN adherence to tumor necrosis factor-alpha- and calcium ionophore-stimulated PAECs was measured before and after reperfusion, and lung PMN sequestration was determined after death. RESULTS: NO-treated animals exhibited lowered pulmonary vascular resistance (P<0.01), as well as improved oxygenation (P<0.01) and survival (P<0.05). Adhesion of PMNs to PAECs was inhibited in the NO group before (P<0.001) and after reperfusion (P<0.0001). Lung PMN sequestration was reduced by NO (P<0.05). CONCLUSIONS: Inhaled NO attenuates I-R injury after NHBD lung transplantation. This is likely due to the prevention of I-R-induced pulmonary vasoconstriction and to the direct effect on peripheral blood PMN adhesion to endothelium, which results in reduced sequestration and tissue injury.

Administration, Inhalation↗
PubMed1997

Chemonucleolysis with human stromelysin-1.

STUDY DESIGN: Immunohistologic analysis was performed on surgically removed samples of herniated nucleus pulposus to examine the expression of stromelysin-1. We performed in vitro and in vivo experiments to determine whether recombinant human (rh) stromelysin-1 is capable of degrading nucleus pulposus. OBJECTIVE: To analyze the production of stromelysin-1 in various types of herniated nucleus pulposus, and to examine the effects of this recombinant protein on nucleus pulposus tissues. SUMMARY OF BACKGROUND DATA: The authors previously demonstrated a progressive decrease in herniated nucleus pulposus size in some of the transligamentous and sequestration types of herniated nucleus pulposus using magnetic resonance imaging. An increased production of stromelysin-1, a cartilage proteoglycan degrading enzyme, in herniated nucleus pulposus was reported recently. The authors speculated that if stromelysin-1 is involved in the degradation of herniated nucleus pulposus, stromelysin-1 itself may be used as a chemonucleolytic agent. METHODS: Immunohistologic analysis using streptoavidin-biotin method was performed on 20 herniated nucleus pulposus samples to investigate the expression of stromelysin-1. Five herniated nucleus pulposus samples were incubated in a tissue culture medium in the presence or absence of rh stromelysin-1. After 24 hours of incubation, their weight changes were measured, and the loss of proteoglycan was assessed by Safranin O staining. Rat nucleus pulposus tissues were obtained from coccygeal intervertebral discs, and autologous subcutaneous transplantation was performed. Rh stromelysin-1 was injected into the grafted materials, and the reduction in size was followed by two-dimensional measurements from the skin surface, using engineer's calipers. RESULTS: Immunohistologic analysis demonstrated the production of stromelysin-1 in the granulation tissues of herniated nucleus pulposus. When stromelysin-1 was injected into the murine nucleus pulposus tissues, they reduced in size more rapidly than the control group. In addition, human herniated nucleus pulposus materials obtained at surgery showed significant weight loss when treated with stromelysin-1 in an organ culture system. Safranin O staining revealed extensive depletion of proteoglycan in these herniated nucleus pulposus samples. CONCLUSIONS: Stromelysin-1 is a possible key enzyme in herniated nucleus pulposus resorption, and stromelysin-1 may be a good candidate for use in chemonucleolysis. Administration of human stromelysin-1 may physiologically facilitate the resorption process of herniated nucleus pulposus, increase the healing rate and decrease complications after chemonucleolysis.

Adult↗
PubMed1997

Delineation of regions important for heteromeric association of hepatitis C virus E1 and E2.

Hepatitis C virus (HCV) is the major causative agent of blood-borne non-A non-B hepatitis. The persistence of HCV infection is believed to reflect escape from the host immunosurveillance system by mutations in hypervariable region 1 (HVR1) of the envelope protein 2 (E2). Two envelope proteins of HCV, E1 and E2, have been reported to form a heteromeric complex but the exact organization of the viral envelope proteins remains uncertain. We examined the interaction of E1 and E2 by far- Western blotting using the bacterial recombinant proteins and also by pull-down assay using mammalian expressed proteins. The major E1-interacting site of E2 was mapped within the N-terminal part of E2 (NCD1) (aa 415 to 500 of the polyprotein). Both HVR1 and HVR2, located at the N-terminal part of E2, were dispensable for the interaction. Although several discontinuous regions within NCD1 seemed to contribute to the strong binding to E1, the highly conserved amino acid sequences flanking HVR2 had the most significant effect. The amino acid residues "WHY" from 489 to 491 of E2 played an especially crucial role since the constructs with the internal deletion or substitution of the residues showed severely impaired E1-binding. The N-terminal part of E1 is important for the E2-binding as determined by far-Western blotting using the mammalian- and bacterial-expressed E2 proteins as probes. The mammalian-expressed, glycosylated forms of the E1 and E2 proteins exhibited E1-E2 binding activities similar to those of the bacterial-expressed, nonglycosylated forms in pull-down assays, suggesting that glycosylation is not prerequisite for the heteromeric complex formation of E1 and E2.

Amino Acid Sequence↗
PubMed1997

Kinetic evaluation of beta-neoendorphin hydrolysis by the somatic and testicular isozymes of human angiotensin-converting enzyme.

Angiotensin-converting enzyme (ACE) has both somatic and testicular isozymes, the former possessing two catalytically active domains, amino-terminal and carboxyl-terminal, while the latter has only the carboxyl-terminal one. We compared hydrolysis processes of the nonapeptide beta-neoendorphin by the two isozymes of human ACE. Both isozymes hydrolyzed the peptide to Tyr1-Gly2-Gly3 by the sequential removal of carboxyl-terminal dipeptides in three consecutive steps. The rate constant values for the second step, conversion of beta-neoendorphin1-7 to Leu-enkephalin, by the somatic isozyme in the presence of 10 or 200 mM NaCl were 4-fold higher than those for the first step, conversion of beta-neoendorphin1-9 to beta-neoendorphin1-7. The k(cat) values of the somatic isozyme for beta-neoendorphin1-7 were 2-fold higher than those for beta-neoendorphin1-9, indicating that beta-neoendorphin1-7 is more rapidly hydrolyzed than beta-neoendorphin1-9. The rate constant value for the second step at 10 mM NaCl was 5-fold higher than that for the testicular isozyme. Similar extent of difference was also observed in k(cat) values for beta-neoendorphin1-7 between the two isozymes. These results suggest that the amino-terminal domain of the somatic isozyme mainly contributes to the conversion of beta-neoendorphin1-7 to Leu-enkephalin at a low NaCl concentration. Optimal chloride concentrations for the individual steps of beta-neoendorphin1-9 hydrolysis differed between the two isozymes.

Humans↗
PubMed1997

Distinct phenotype of leukemic T cells with various tissue tropisms.

There is an emerging concept, the validity of which remains to be proven, that preferential expression of selective adhesion molecules on particular T cell subsets may result in tissue-specific migration. L-selectin, cutaneous lymphocyte-associated Ag (CLA), and integrin alpha4beta7 are proposed to be involved in selective migration of T cell subsets into peripheral lymph nodes, skin, and gastrointestinal mucosa, respectively. Adult T cell leukemia (ATL) is associated with lymphoid infiltration of tissues and secondary lymphoid organs. To clarify the role of these putative homing molecules in vivo, we assessed their expression on circulating ATL cells from patients with lymph node, skin, and gut involvement. L-selectin expression was significantly higher on peripheral ATL cells in patients with lymphadenopathy than in patients without it. CLA was highly expressed on peripheral ATL cells compared with normal T cells: its expression was also significantly higher on peripheral ATL cells from patients with skin involvement compared with cells from patients without it. beta7 was particularly highly expressed on peripheral ATL cells from patients with gastrointestinal involvement. In summary, the differential expression of beta7 and beta1 on peripheral ATL cells correlates with the presence of gastrointestinal involvement. Similarly, the presence of skin involvement is associated with the expression of CLA(high)beta7low on peripheral ATL cells. These results, which are consistent with the molecules CLA and alpha4beta7 mediating preferential T cell migration to the skin and gastrointestinal mucosa, respectively, may allow for a refinement of the classification of lymphoid neoplasms on the basis of differential expression of homing molecules.

Adult↗
PubMed1997

Hepatitis B virus X protein is a transcriptional modulator that communicates with transcription factor IIB and the RNA polymerase II subunit 5.

Hepatitis B virus X protein (HBx) transactivates viral and cellular genes through a wide variety of cis-elements. However, the mechanism is still obscure. Our finding that HBx directly interacts with RNA polymerase II subunit 5 (RPB5), a common subunit of RNA polymerases, implies that HBx directly modulates the function of RNA polymerase (Cheong, J. H., Yi, M., Lin, Y., and Murakami, S. (1995) EMBO J. 14, 142-150). In this context, we examined the possibility that HBx and RPB5 interact with other general transcription factors. HBx and RPB5 specifically bound to transcription factor IIB (TFIIB) in vitro, both of which were detected by either far-Western blotting or the glutathione S-transferase-resin pull-down assay. Delineation of the binding regions of these three proteins revealed that HBx, RPB5, and TFIIB each has two binding regions for the other two proteins. Co-immunoprecipitation using HepG2 cell lysates that express HBx demonstrated trimeric interaction in vivo. Some HBx substitution mutants, which had severely impaired transacting activity, exhibited reduced binding affinity with either TFIIB or RPB5 in a mutually exclusive manner, suggesting that HBx transactivation requires the interactions of both RPB5 and TFIIB. These results indicated that HBx is a novel virus modulator that facilitates transcriptional initiation by stabilizing the association between RNA polymerase and TFIIB through communication with RPB5 and TFIIB.

Gene Expression Regulation, Viral↗
PubMed1997

Classification of catechol 1,2-dioxygenase family: sequence analysis of a gene for the catechol 1,2-dioxygenase showing high specificity for methylcatechols from Gram+ aniline-assimilating Rhodococcus erythropolis AN-13.

Gram+ aniline-assimilating Rhodococcus erythropolis AN-13 (AN-13) produces catechol 1,2-dioxygenase (C12O) showing high enzymatic activities for 3- and 4-methylcatechols [Aoki et al. (1984) Agric. Biol. Chem. 48, 2087-2095]. A 3.0 kb Sau3AI fragment carrying a gene encoding C12O(catA) was cloned by selection of transformants showing C12O activity from a gene library of AN-13. Furthermore, we specified a 1.6 kb SalI fragment containing catA from the Sau3AI fragment by subcloning. Sequence analysis revealed that the 1.6 kb SalI fragment carried a 855 bp open reading frame (ORF) encoding the entire AN-13 catA, preceded by a potential ribosome binding site (RBS). From comparison of the deduced amino acid (aa) sequence of C12O from AN-13 with other C12O reported previously, it was found that the AN-13 enzyme shares 56.0% aa sequence identity with C12o from Arthrobacter sp. mA3 (mA3) [Eck and Belter (1991) Gene 123, 87-92] compared with less than 36.4% aa sequence identities with others. In conclusion, we classified all C12O including the AN-13 enzyme into three subfamilies on the basis of similarity of aa sequences, numbers of aa residues, and substrate specificity.

Amino Acid Sequence↗
PubMed1997

Treatment of Ramsay Hunt syndrome with acyclovir-prednisone: significance of early diagnosis and treatment.

Although the antiviral agent acyclovir is currently used for the treatment of Ramsay Hunt syndrome, its effects on facial nerve and hearing recovery remain controversial. We retrospectively analyzed the effects of acyclovir-prednisone treatment in 80 Ramsay Hunt patients. Of 28 patients for whom treatment was begun within 3 days of the onset of facial paralysis, the recovery from paralysis was complete in 21 (75%). By comparison, of 23 patients for whom treatment was begun more than 7 days after onset, recovery from facial paralysis was complete in only 7 (30%). A significant difference in facial nerve recovery was found between these groups. Early administration of acyclovir-prednisone was proved to reduce nerve degeneration by nerve excitability testing. Hearing recovery also tended to be better in patients with early treatment. There was no significant difference in facial nerve outcome between intravenous and oral acyclovir treatment.

Acyclovir↗
PubMed1997

Inhaled nitric oxide and pentoxifylline in rat lung transplantation from non-heart-beating donors. The Paris-Sud University Lung Transplantation Group.

BACKGROUND: In non-heart-beating donor lung transplantation, postmortem warm ischemia poses a special challenge. Inhaled nitric oxide and pentoxifylline have been shown to attenuate ischemia-reperfusion injury after lung transplantation. We hypothesized that concomitant administration of inhaled nitric oxide and pentoxifylline would result in a synergistic effect on ischemia-reperfusion lung injury. METHODS: Lungs were harvested from non-heart-beating donors after 30 minutes of in situ warm ischemia, flushed, and stored for 2 hours at 4 degrees C before left lung transplantation in rats. Inhaled nitric oxide (30 ppm) was added during cadaver ventilation and reperfusion; pentoxifylline was given intravenously throughout reperfusion. The following groups were studied (n = 8 each): control, pentoxifylline, nitric oxide, and nitric oxide+pentoxifylline. Hemodynamic indices and arterial blood gases were obtained after ligation of the right pulmonary artery. Lung myeloperoxidase and wet/dry ratio were measured after death. RESULTS: All rats that did not receive nitric oxide died within 10 minutes after ligation. Inhaled nitric oxide significantly decreased pulmonary vascular resistance and improved recipient survival. Nitric oxide + pentoxifylline improved pulmonary vascular resistance, arterial oxygen tension, and survival even further and reduced lung myeloperoxidase as compared with the group that received nitric oxide only. Preservation solution flush time was significantly decreased in both groups receiving nitric oxide, suggesting that inhaled nitric oxide used during cadaver ventilation allows for a more even distribution of the preservation solution. CONCLUSIONS: We conclude that treatment with inhaled nitric oxide + pentoxifylline results in a synergistic protection from ischemia-reperfusion injury after non-heart-beating donor lung transplantation. This is likely the result of a dual action on the graft vasculature and neutrophil sequestration.

Animals↗
PubMed1997

Augmentation of immune response by an analog of the antigenic peptide in a human T-cell clone recognizing mutated Ras-derived peptides.

T-cells that recognize mutated p21 Ras are relevant to immune surveillance systems against cancer. We report here evidence that immune responses of a T-cell clone recognizing mutated p21 Ras can be augmented by an analog peptide. Using spleen cells from a gastric cancer patient, we established the CD4+ alpha beta Th1-like clone C27 that recognizes wild-type (3EYKLVVVGAGGVGKS17) and mutated p21 Ras protein molecules and peptides, in an HLA-DR1-restricted manner. C27 responded prominently to mutated Ras peptides carrying Val or Ala at position 12, as compared to wild-type and other mutated peptides. C27 also exhibited a much stronger response to a mutated p21 Ras whole-protein molecule-carrying Val at position 12, as compared with the wild-type protein. The proliferative response and production of GM-CSF, TNF-alpha, and IFN-gamma by C27 were further augmented by replacing the possible first DR anchor 4Tyr of the mutated Ras peptide with Trp, a more potent anchor residue for the DR1 molecule. Enhancement of peptide antigenicity by substituting the HLA anchor residue of an antigenic peptide recognized by tumor-reactive T-cells may prove to be a novel strategy for antigen-specific cancer immunotherapy.

Adjuvants, Immunologic↗
PubMed1997

Mucus escape reaction that involves the mandible: a case report and diagnostic imaging considerations.

We present a case of mucus escape reaction in which we encountered difficulty in interpreting the images acquired by plain radiography, computed tomography, and magnetic resonance imaging. The 48-year-old male Japanese patient was referred for evaluation of a gradual swelling subjacent to the inferior border of the left mandible. At the early imaging examinations, magnetic resonance imaging provided information crucial to resolving the issue of whether the lesion consisted of a central malignant disease process or a malignant disease in the submandibular space or both of these two separate disease entities. Magnetic resonance imaging demonstrated no evidence of tumorous lesion, but rather showed a fluid-containing cavity that was also confirmed by the subsequent intrasurgical inspection. On further consideration of these imaging findings, we concluded that the entity was mucus escape reaction with simultaneous occurrence of an intraconnective tissue hemorrhage adjacent to the left submandibular gland, concomitant extensive bony defect of the left mandible and lingual cortical defect, and chronic sialoadenitis of the left submandibular gland.

Diagnosis, Differential↗
PubMed1997

Serum thrombopoietin levels in patients undergoing autologous peripheral blood stem cell transplantation.

Recently, the ligand for c-mpl has been cloned and initial studies have shown it to be the platelet regulatory factor, thrombopoietin (TPO). To elucidate the role of TPO in the reconstitution of megakaryopoiesis and platelet production after stem cell transplantation, we measured serum TPO levels in nine patients undergoing autologous peripheral blood stem cell transplantation (PBSCT) and in healthy volunteers. Serum TPO levels significantly correlated with the degree of peripheral thrombocytopenia and a strong inverse correlation between serum TPO level and platelet count was observed (r = -0.700, P < 0.001). Serum TPO levels began to rise as the platelet count decreased after chemotherapy, TPO levels peaked at over 25.00 fmoles/ml between days 0 and 10; TPO levels then decreased gradually as the platelet count began to rise. One patient with multiple myeloma received purified CD34+ peripheral blood stem cells. No difference was observed in the kinetics of serum TPO levels between unfractionated and purified PBSCT. These observations suggest that TPO plays a critical role in the reconstitution of megakaryopoiesis and platelet production after PBSCT.

Adolescent↗
PubMed1997

Immunoregulatory roles of adhesive interactions between lymphocytes and gingival fibroblasts.

Chronic adult periodontitis is usually characterized by inflammatory cell accumulation in the extravascular periodontal connective tissue. In order to reveal how the lymphocyte migration and retention in periodontal lesions is regulated, we have focused on the molecular basis for the adhesive interactions between lymphocytes and human gingival fibroblasts (HGF). In this study, we investigated the involvement of cell adhesion molecules in adhesive interactions between lymphocytes and HGF. We found that activated lymphocytes bound strongly to HGF and VLA integrins, extracellular matrix receptors, play crucial roles in the binding. Interestingly, we first revealed that CD44 molecules (hyaluronate receptor) on lymphocytes also participated in lymphocyte-HGF interactions and that hyaluronate anchored on the surface of HGF functioned as the ligand for CD44. In addition, when HGF were stimulated with inflammatory cytokines such as IL-1, TNF alpha and IFN gamma, the binding avidity between lymphocytes and HGF was significantly increased and the adhesion was mainly mediated by LFA-1/ICAM-1 pathway. We then examined the possibility whether lymphocyte-HGF interaction may cause activation of HGF. When HGF directly interacted with lymphocytes for 3 h, IL-1 beta mRNA expression was clearly increased in HGF. These findings suggested that the adhesive interactions between lymphocytes and HGF was mediated at least by VLA integrins, LFA-1/ICAM-1 and CD44/hyaluronate and that the heterotypic cell-cell interactions could mutually cause intracellular signal transduction.

Cell Adhesion↗
PubMed1997

Lymphocyte-fibroblast interactions.

Chronic inflammatory reactions are usually characterized by inflammatory cell accumulation in the extravascular connective tissue. In such sites, inappropriate activation of circulating or resident lymphocytes becomes self-perpetuating and can lead to chronic tissue destruction. In addition to that, the locally infiltrated lymphocytes should have an opportunity to interact directly with fibroblasts composing the connective tissue. The direct interactions of those different cell types seem to play important roles in lymphocyte lodging and retention in such sites. Thus, for clarification of the immunopathogenesis of the chronic inflammatory diseases, including periodontitis, it is important that the molecular mechanisms involved in the heterotypic cell-cell interactions be revealed. In fact, it has been demonstrated that lymphocytes interact with various non-hematopoietic cells, such as epithelial cells and endothelial cells. Regarding interactions with fibroblasts, it has been shown that IFN gamma-stimulated fibroblasts can regulate the proliferative responses of T-lymphocytes both positively and negatively. Furthermore, activated lymphocytes have demonstrated strong binding ability to various fibroblast cell lines. Blocking experiments utilizing monoclonal antibodies specific to various cell adhesion molecules revealed that very late antigen (VLA) integrins, lymphocyte-function-associated antigen (LFA-1)/intercellular adhesion molecule-1 (ICAM-I), CD44/hyarulonate are, at least in part, involved in lymphocyte-fibroblast interactions. In addition, recent findings raised the possibility that the adhesive interactions between lymphocytes and fibroblasts influenced the various cellular functions of each cell type. In fact, it was recently demonstrated that the adhesive interactions stimulated fibroblasts to increase expression of inflammatory cytokine mRNA. These results strongly suggest that fibroblasts are not merely innocent bystanders but actively participate in local inflammatory reactions by directly interacting with locally infiltrated lymphocytes.

Animals↗
PubMed1997

Expression of Indian hedgehog in osteoblasts and its posttranscriptional regulation by transforming growth factor-beta.

Indian hedgehog (Ihh) was recently reported to be expressed in chondrocytes and to regulate chondrocyte differentiation. This report examined the expression of Ihh in osteoblastic cells and its regulation by calcitropic cytokines. We found that Ihh messenger RNA (mRNA) was expressed as a single 2.5-kilobase band at a modest level in rat osteoblastic osteosarcoma ROS17/2.8 cells. In sharp contrast to the previous observation of dpp regulation of hedgehog expression in Drosophila embryos, bone morphogenetic protein-2 did not affect Ihh expression in these cells. On the other hand, treatment with 2 ng/ml transforming growth factor-beta1 (TGFbeta1) increased the steady state level of Ihh mRNA 2- to 4-fold. Western blot analysis of the cell lysates using antisera also showed enhancement of the Ihh protein level by TGFbeta1 treatment. The effect of TGFbeta1 on Ihh mRNA abundance started within 3 h, peaked at 24 h and lasted at least 48 h after the initiation of the treatment. The effect of TGFbeta1 on the increase in Ihh mRNA was dose dependent, starting at 0.2 ng/ml and saturating at 2 ng/ml. Neither actinomycin D nor cycloheximide blocked this effect. Experiments using 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole showed an enhancement of Ihh mRNA stability by TGFbeta1, indicating the presence of posttranscriptional regulation. We then examined the effects of TGFbeta1 on Ihh mRNA in osteoblast-enriched cells isolated from neonatal rat calvariae. TGFbeta1 also enhanced Ihh mRNA expression in these cells. Our data indicate for the first time that Ihh is one of the members of the cytokines produced by osteoblastic cells and that the expression of Ihh is regulated posttranscriptionally by TGFbeta.

Animals↗
PubMed1997

Purification and characterization of a thermostable pyruvate kinase from the actinomycete Microbispora thermodiastatica.

The pyruvate kinase of Microbispora thermodiastatica was purified to homogeneity and some properties of the enzyme were characterized. The molecular weight of the enzyme by gel filtration is 277,000. The subunit molecular weight is 55,000 by SDS-polyacrylamide gel electrophoresis, and only one N-terminal amino acid sequence was obtained. It had a pH optimum around pH 4.5 to 7.0 and was stable over the range of pH 4.0-8.0. The enzyme is thermostable and no activity was lost after heat treatment at 55 degrees C for 60 min. AMP activated this enzyme and the saturation curve of the enzyme for PEP changed from sigmoidal type to hyperbolic type in the presence of AMP.

Actinomycetales↗