Complete genome sequence of Streptococcus troglodytae TKU31 isolated from the oral cavity of a chimpanzee (Pan troglodytes)

Streptococcus troglodytae TKU31 was isolated from the oral cavity of a chimpanzee (Pan troglodytes) and was found to be the most closely related species of the mutans group streptococci to Streptococcus mutans. The complete sequence of TKU31 genome consists of a single circular chromosome that is 2,097,874 base pairs long and has a G + C content of 37.18%. It possesses 2082 coding sequences (CDSs), 65 tRNAs and five rRNA operons (15 rRNAs). Two clustered regularly interspaced short palindromic repeats, six insertion sequences and two predicted prophage elements were identified. The genome of TKU31 harbors some putative virulence associated genes, including gtfB, gtfC and gtfD genes encoding glucosyltransferase and gbpA, gbpB, gbpC and gbpD genes encoding glucan‐binding cell wall‐anchored protein. The deduced amino acid identity of the rhamnose‐glucose polysaccharide F gene (rgpF), which is one of the serotype determinants, is 91% identical with that of S. mutans LJ23 (serotype k) strain. However, two other virulence‐associated genes cnm and cbm, which encode the collagen‐binding proteins, were not found in the TKU31 genome. The complete genome sequence of S. troglodytae TKU31 has been deposited at DDBJ/European Nucleotide Archive/GenBank under the accession no. AP014612.     

Detection of Ubiquitinated Dermcidin in Gingival Crevicular Fluid in Periodontal Disease

Periodontal disease is an inflammatory disease caused by gram-negative bacteria, such as Porphyromonas gingivalis and Actinobacllus actinomycetemcomitans. Antimicrobial peptides kill organisms, such as gram-negative and gram-positive bacteria, mycobacteria, enveloped viruses, and fungi. We previously identified the antimicrobial peptide dermcidin (DCD) in the gingival crevicular fluid (GCF) using proteomic analyses. Moreover, western blot analysis revealed that the molecular weights of GCF protein bands considerably varied (approximately 27 kDa). We attempted to explore the considerable variation in the molecular weights of protein bands using on-membrane digestion and liquid chromatography–tandem mass spectrometry (LC–MS/MS) analyses. We examined ubiquitin among the DCD-interacting proteins. In immunoprecipitation experiments, ubiquitinated DCD was detected by western blotting and by immunoprecipitation with an antibody against DCD and mono- or poly-ubiquitinated proteins. These analyses indicated the possible involvement of the ubiquitination reaction. Ubiquitinated DCD may protect against periodontal bacterial pathogen invasion in GCF.     

A relation between osteoclastogenesis inhibition and membrane-type estrogen receptor GPR30

Disruption of the cooperative balance between osteoblasts and osteoclasts causes various bone disorders, some of which are because of abnormal osteoclast recruitment. Osteoporosis, one of the bone disorders, is not effectively treated by currently available medicines. In addition to the development of novel drugs for palliative treatment, the exploitation of novel compounds for preventive treatment is important in an aging society. Quercetin, a major flavonoid found in many fruits and vegetables, has been expected to inhibit cancer and prevent several diseases because of its anti-inflammatory and estrogenic functions. It has been reported that quercetin has the potential to reduce bone resorption, but the mechanism by which this compound affects the differentiation of osteoclasts remains unknown. Here, using a bone marrow cell-based in vitro osteoclast differentiation system from bone marrow cells, we found that the ability of quercetin to inhibit osteoclastogenesis was related to its estrogenic activity. The inhibition was partially blocked by a specific antagonist for the nuclear receptor estrogen receptor α, but a specific antagonist of the membrane-type receptor GPR30 completely ablated this inhibition. Furthermore, quercetin suppressed the transient increase of Akt phosphorylation induced by the stimulation of macrophage colony-stimulating factor and receptor activator of NF-κB ligand with no effect on MAPK phosphorylation, suggesting exquisite crosstalk between cytokine receptor and G-protein coupled receptor signaling. These results indicate the important role of GPR30 in osteoclast differentiation and provide new insights to the development of new treatments for osteoporosis.     

A monoclonal antibody against horse kidney (Na+ + K+)-ATPase inhibits sodium pump and E2K to E1 conversion of (Na+ + K+)-ATPase from outside of the cell membrane

Monoclonal antibodies against horse kidney outer medulla (Na+ + K+)-ATPase were prepared. One of these antibodies (M45-80), was identified as an IgM, recognized the alpha subunit of the enzyme. M45-80 had the following effects on horse kidney (Na+ + K+)-ATPase: (1) it inhibited the enzyme activity by 50% in 140 mM Na+ and by 80% in 8.3 mM Na+; (2) it increased the Na+ concentration necessary for half-maximal activation (K0.5 for Na+) from 12.0 to 57.6 mM, but did not affect K0.5 for K+; (3) it slightly increased the K+-dependent p-nitrophenylphosphatase (K-pNPPase) activity; (4) it inhibited phosphorylation of the enzyme with ATP by 30%, but did not affect the step of dephosphorylation; and (5) it enhanced the ouabain binding rate. These data are compatible with a stabilizing effect on the E2 form of (Na+ + K+)-ATPase. M45-80 was concluded to bind to the extracellular surface of the plasmamembrane, based on the following evidence: (1) M45-80 inhibited by 50% the ouabain-sensitive 86Rb+ uptake in human intact erythrocytes from outside of the cells; (2) the inhibition of (Na+ + K+)-ATPase activity in right-side-out vesicles of human erythrocytes was greater than that in inside-out vesicles; and (3) the fluorescence intensity due to FITC-labeled rabbit anti-mouse IgM that reacted with M45-80 bound to the right-side-out vesicles was much greater than that in the case of the inside-out vesicles.     

Induction of the Acrosome Reaction of Hemicentrotus pulcherrimus Spermatozoa by the Egg Jelly Molecules, Fucose-Rich Glycoconjugate and Spem-Activating Peptide I

A fucose-rich glycoconjugate (FRG) was isolated from egg jelly of the sea urchin Hemicentrotus pulcherrimus by gel filtration. FRG induced the acrosome reaction in H. pulcherrimus spermatozoa in a concentration-dependent manner, although it showed about half the activity of the original unfractionated jelly. Synthetic sperm-activating peptide I (SAP-I: Gly-Phe-Asp-Leu-Asn-Gly-Gly-Gly-Val-Gly) increased the rate of the acrosome reaction induced by FRG; the maximal rate of the acrosome reaction with FRG and SAP-I being that of the unfractionated jelly. The half-maximal increase in induction of the acrosome reaction by SAP-I with FRG occurred at 4 × 10⁻¹⁰ M SAP-I, which was almost the same concentration inducing half-maximal stimulation of sperm respiration. Pronase digestion of FRG resulted in an 50% decrease in induction of the acrosome reaction and also in the elevation of cAMP in sperm. Some reagents (monensin and 3-isobutyl-1-methylxanthine) which increase intracellular pH, Ca²⁺ and cyclic nucleotides also increased the rates of the acrosome reaction induced by FRG or pronase-digested FRG. However, the rates did not reach those with FRG or pronase-digested FRG with SAP-I. These results indicate that SAP-I promotes induction of the acrosome reaction by acting as a specific co-factor of FRG.     

Implications of the Hiroshima-Nagasaki genetic studies for the estimation of the human "doubling dose" of radiation

Since 1946 a continuous effort to evaluate the potential genetic effects of the atomic bombs has been sustained. Observations on children born in Hiroshima and Nagasaki include sex ratio, congenital malformations, stillbirths, survival of liveborn infants, chromosomal abnormalities (sex chromosomal abnormalities and balanced chromosomal rearrangements), mutations altering protein structure or activity, and physical growth and development. There are no statistically significant differences between the children of parents who received increased amounts of radiation at the time of the bombings and those whose parents did not. However, the difference between the two sets of children is consistent with the hypothesis of a genetic effect of the exposure, but its magnitude suggests humans are not as sensitive to the genetic effects of radiation as projected from the mouse paradigm.     

Interleukin-1α: Its possible roles in cancer therapy

Our studies on recombinant human IL-1 polypeptide were summarized with respect to molecular cloning, production, quantitative assay systems, antitumor activity, myelorestorative activity and augmentation of host resistance to infections.Recombinant human IL-1 (18 kDa) was produced through the expression of the cloned human IL-1 cDNA inEscherichia coli and purified to an endotoxin-free homogeneous polypeptide. The human IL-1 inhibited dose-dependently the growth of syngeneic murine tumors transplanted in mice and completely regressed the tumors in some cases, and its antitumor activity was significantly enhanced in combination with indomethacin. The human IL-1 accelerated the recovery of the numbers of peripheral leukocytes and neutrophils in a dose-dependent manner at a dose as low as 10 ng/mouse/day in myelo suppressed mouse model produced by administering anticancer chemotherapeutic drugs. The myelorestorative effect of IL-1 was observed not only on leukocytes/neutrophils, but also on platelets in myelosuppressed mice. In addition, the human IL-1 markedly augmented dose-dependently resistance of normal and leukopenic mice to various microbial infections.These results suggested that recombinant human IL-1 might be useful for cancer therapy from the viewpoints of improving adverse effects such as myelosuppression caused by chemotherapy and/or radiation therapy and preventing infections. In addition, use of IL-1 may permit more intensive chemo- and radiation therapies using higher doses. Finally, the antitumor activity of the IL-1 itself may play an important role.     

Endothelin: a potent vasoconstrictor associated with coronary vasospasm

Endothelin, administered into the coronary arteries of anesthetized dogs, produced a profound and long-lasting reduction in coronary blood flow with electrocardiographical evidence of myocardial ischemia. Coronary angiography revealed delayed filling of the distal branches and, in some cases, cessation of the blood flow distal to the epicardial portions of coronary arteries. The coronary vasoconstriction induced by endothelin subsided after intracoronary administration of nitroglycerin. Pretreatment with the Ca2+-channel antagonist, nitrendipine, suppressed endothelin-induced vasoconstriction. These findings suggest that endothelin, produced by vascular endothelial cells, may contribute to the pathogenesis of coronary vasospasm.