VLA-5 is expressed by mouse and human long-term repopulating hematopoietic cells and mediates adhesion to extracellular matrix protein fibronectin

Fibronectin (FN), an extracellular matrix protein, is involved in the adhesion and migration of hematopoietic cells and has been shown to enhance retroviral gene transfer into primitive hematopoietic cells by co-localization of target cells and retrovirus when used as a substrate in vitro. We have previously found that mouse hematopoietic stem cells could be transduced on a FN fragment that included the recognition sequence Arg-Gly-Asp (RGD), suggesting that stem cells may express the integrin very late antigen (VLA)-5. To address this, we investigated the binding of mouse and human hematopoietic cells to recombinant peptides that contained one or a combination of the three principle cell-binding domains of FN. These domains included the VLA-5- binding sequence RGD, the VLA-4-binding site CS1, and the high affinity heparin-binding domain. Here we show that mouse long-term in vivo repopulating stem cells, as well as primitive human NOD/SCID mouse repopulating cells, can bind extracellular matrix protein FN by using integrin VLA-5 in vitro. This binding is specific and can be inhibited by antibodies to VLA-5. In addition, preincubation of BM cells with peptide CH-296, which contains all three primary FN-binding domains, decreased the engraftment of cells in the bone marrow in vivo, while intravenous injection of the same peptide induced an increase of progenitor cells in the spleen. In summary, our data demonstrate that VLA-5 is expressed on primitive mouse and human hematopoietic cells and suggest that there may be significant cooperation between integrin receptors and proteoglycan molecules in the engraftment of bone marrow cells and hematopoietic cell adhesion in vivo.

Objective tinnitus caused by an aberrant internal carotid artery

We report the case of a 29 year-old woman who complained of pulsatile tinnitus and impaired hearing. On otoscopic examination, her right tympanic membrane was observed to be in contact with a mass in the middle ear cavity, with the formation of a meniscus at the point of contact. Using a high-sensitivity microphone inserted into the external auditory canal, we recorded pulsatile tinnitus that was synchronous with the electrocardiogram. Magnetic resonance angiography revealed that the middle ear mass was an aberrant internal carotid artery coursing through the hypotympanum.

Suppressive effects of the oral administration of Lactobacillus casei on type II collagen-induced arthritis in DBA/1 mice

We investigated the effects of the oral administration of the viable bacterium Lactobacillus casei strain Shirota (LcS), on the development of type II collagen (CII)-induced arthritis (CIA) in DBA/1 mice. Male DBA/1 mice were immunized with an emulsion of 100 microg of CII and complete Freund's adjuvant (CFA). The mice were then given orally a suspension of LcS or distilled water (DW) during the experiment. We observed the development of CIA in the mice, and determined the in vivo and ex vivo CII-specific immune responses in the control and LcS-administered mice. In the control mice, we observed the onset of arthritis at the 27th day after the CII-immunization, and then the severity of CIA developed gradually. In the tested mice, the LcS-treatment reduced the incidence and the development of CIA and the levels of antibody to CII in serum compared with the control mice. The CII-specific IgG2a and IgG2b antibodies in serum were also down regulated in the tested mice. The administration of this bacterium also inhibited delayed-type hypersensitivity response to CII in DBA/1 mice immunized with CII and CFA. The orally administered-LcS suppressed the CII-specific secretion of interferon-gamma from splenocytes ex vivo. From these results, we concluded that the oral administration of LcS was able to modify the humoral and cellular immune responses to CII, and these modifications could result in the reduction of the development of CIA in DBA/1 mice.

The structures of asparagine-linked oligosaccharides of rat liver cathepsin L reflect the substrate specificity of lysosomal alpha-mannosidase

We have studied the structures of asparagine-linked oligosaccharides of cathepsin L purified from rat liver in detail. The oligosaccharides released from rat liver cathepsin L on glycopeptidase-F treatment were tagged with 2-aminopyridine at their reducing ends. The pyridylamino (PA) derivatives were separated into seven fractions according to molecular size by normal-phase HPLC. The structure of each oligosaccharide thus isolated was analyzed by reversed-phase HPLC and characterized by ion-spray mass spectrometry and high-resolution proton nuclear magnetic resonance (1H-NMR) spectroscopy. Our results indicate that the asparagine-linked oligosaccharides of rat liver cathepsin L are of the oligomannose type, having two to six mannose residues. Among them, the five major ones are Manalpha1-6Manbeta1-4-GlcNAcbeta1-4GlcNAc, Manalpha1 -6Manalpha1-6Manbeta1-4GIcNAcbeta1-4GlcNAc, Manalpha1-6(Manalpha1-3)-Manalpha1-6Manbeta1- 4GlcNAcbeta1-4GlcNAc, Manalpha1-6(Manalpha1-3)Manalpha1-6(Manalpha1-3) Manbeta1-4Glc-NAcbeta1-4GlcNAc, and Manalpha1-6(Manalpha1-3)Manalpha1-6(Manalpha1-++ +2Manalpha1-3)Manbeta1-4GlcNAcbeta1-4Glc-NAc. Their structures are shown to be products of Man6GlcNAc2 hydrolysis with lysosomal alpha-mannosidase.

Autoantibodies against CD38 (ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase) that impair glucose-induced insulin secretion in noninsulin- dependent diabetes patients

Cyclic ADP-ribose (cADPR) has been shown to be a mediator for intracellular Ca2+ mobilization for insulin secretion by glucose in pancreatic beta cells, and CD38 shows both ADP-ribosyl cyclase to synthesize cADPR from NAD+ and cADPR hydrolase to hydrolyze cADPR to ADP-ribose. We show here that 13.8% of Japanese non-insulin-dependent diabetes (NIDDM) patients examined have autoantibodies against CD38 and that the sera containing anti-CD38 autoantibodies inhibit the ADP-ribosyl cyclase activity of CD38 (P </= 0.05). Insulin secretion from pancreatic islets by glucose is significantly inhibited by the addition of the NIDDM sera with anti-CD38 antibodies (P </= 0.04-0.0001), and the inhibition of insulin secretion is abolished by the addition of recombinant CD38 (P </= 0.02). The increase of cADPR levels in pancreatic islets by glucose was also inhibited by the addition of the sera (P </= 0.05). These results strongly suggest that the presence of anti-CD38 autoantibodies in NIDDM patients can be one of the major causes of impaired glucose-induced insulin secretion in NIDDM.

Synthesis of a high-mannose-type glycopeptide analog containing a glucose-asparagine linkage

The title compound was prepared by enzymatic transfer of oligosaccharide to a synthetic pentapeptide containing the Glc-Asn linkage. The compound was not hydrolyzed by glycoamidases from plant and bacterial sources, but it inhibited both enzymes in the micromolar range. Its activity is compared to other potential inhibitors.

Histopathological study of the role of CD4- and CD8-positive T cells on bone resorption induced by Escherichia coli endotoxin

The purpose of this study was to clarify the involvement of CD4+ and CD8+ T cells on bone resorption induced by Escherichia coli endotoxin. Two kinds of monoclonal antibodies, anti-CD4 and/or anti-CD8, were employed for the depletion of each or both T cell subsets. E. coli endotoxin was injected into mouse mesial gingiva of the first molar of the left mandible every 48 hours for up to 14 days (7 injections). The mice were divided into four groups: CD4-depleted, CD8-depleted, T cell-depleted, and normal. The mice were sacrificed on the day after the 1st, 3rd, 4th, 5th, and 7th injection and alveolar bone was examined histopathologically and histomorphometrically. Bone surface in contact with osteoclasts was defined as the site of active resorption and the ratios of active resorption were compared among the four groups. In addition, sections obtained after the 1st, 4th, and 7th injection were immunohistologically stained in order to confirm the presence or absence of CD4+ or CD8+ T cells. Alveolar bone resorption gradually increased in normal mice as the number of injections increased. In contrast, alveolar bone resorption was significantly weaker in each or both subset-depleted mice. For the duration of the experimental period, the number of CD4+ T cells in CD8-depleted and normal mice significantly increased with increasing bone resorption. Considering the function of CD4+ and CD8+ T cells, these results suggest that each subset preferentially acts as a macrophage activator in the early period of bone resorption induced by E. coli endotoxin.

High-efficiency gene transfer into normal and adenosine deaminase-deficient T lymphocytes is mediated by transduction on recombinant fibronectin fragments

Primary human T lymphocytes are powerful targets for genetic modification, although the use of these targets in human gene therapy protocols has been hampered by low levels of transduction. We have shown previously that significant increases in the transduction of hematopoietic stem and progenitor cells with retroviral vectors can be obtained by the colocalization of the retrovirus and target cells on specific fibronectin (FN) adhesion domains (H. Hanenberg, X. L. Xiao, D. Dilloo, K. Hashino, I. Kato, and D. A. Williams, Nat. Med. 2:876-882, 1996). We studied the transfer of genes into primary T lymphocytes by using FN-assisted retroviral gene transfer. Activated T lymphocytes were infected for three consecutive days on the recombinant FN fragment CH-296 with a retroviral vector encoding the murine B7-1 protein. Transduced lymphocytes were analyzed for murine B7-1 expression, and it was found that under optimal conditions, 80 to 89% of the CD3+ lymphocytes were transduced. Gene transfer was predominantly augmented by the interaction between VLA-4 on the T lymphocytes and the FN adhesion site CS-1. Adenosine deaminase (ADA)-deficient primary T lymphocytes transduced on CH-296 with a retrovirus encoding murine ADA (mADA) exhibited levels of mADA activity severalfold higher than the levels of the endogenous human ADA protein observed in normal human T lymphocytes. Strikingly, the long-term expression of the transgene was dependent on the activation status of the lymphocytes. This approach will have important applications in human gene therapy protocols targeting primary T lymphocytes.

Enhancement of retroviral gene transduction on a dish coated with a cocktail of two different polypeptides: one exhibiting binding activity toward target cells, and the other toward retroviral vectors

CH-296, a recombinant fragment of human fibronectin (FN) composed of the cell-binding domain (C-domain), heparin-binding domain II (H-domain), and CS1 site, enhances the retrovirus-mediated gene transduction (GT) of hematopoietic stem cells. The RGD sequence in the C-domain is recognized by a variety of cell types through integrin VLA-5, and the LDV sequence in the CS1-site is recognized by integrin VLA-4. Retrovirus particles were also found to bind to the H-domain. Consequently, the CH-296 fragment can enhance GT through binding to both retrovirus particles and target cells that express integrins VLA-5 and/or VLA-4. In this study, we found that the GT efficiency can be maintained at levels comparable to that of CH-271, a FN fragment similar to CH-296 but lacking the CS1 site, when a cocktail of separated functional domains of CH-271 is used. When a dish was coated with a mixture of the C-domain and H-domain (molar ratio, 1:10), the GT efficiency of NIH3T3 cells reached the same level as that of the mother fragment, CH-271. The H-domain in the cocktail can be replaced with other virus-binding components, polylysine, FGF, and the insulin-binding domain of ColV, without the loss of GT efficiency. With other than FN fragments, a cocktail of erythropoietin and polylysine caused higher GT efficiency of Epo-receptor expressing TF-1 cells than in the case of each component alone.

Identification of the catalytic triad residues of porcine liver acylamino acid-releasing enzyme

Acylamino acid-releasing enzyme (AARE) [EC 3.4.19.1] is a tetrameric serine protease, which belongs to the oligopeptidase family and specifically removes acetyl amino acids from N-terminally acetylated peptides. By using diisopropyl fluorophosphate, we previously identified one of the residues comprising the catalytic triad of this enzyme as Ser587 [Miyagi, M. et al. (1995) J. Biochem. 118, 771-779]. To elucidate the other two residues forming the catalytic triad of this new serine-type protease, wild-type and four mutant AAREs, in which each candidate residue of the catalytic triad deduced from sequence alignment with other oligopeptidases was substituted by site-directed mutagenesis, were expressed in Escherichia coli as fusion proteins with short peptide chains at both N- and C-termini of a subunit of porcine liver enzyme. All of the recombinant AAREs were estimated to have similar conformational and quaternary structures to the native porcine liver enzyme from their CD spectra and behavior on gel-filtration, but the mutants in which Ala587, Asn675, or Tyr707 was substituted for Ser587, Asp675, or His707, respectively, did not show detectable hydrolytic activity toward acetyl-L-methionyl L-alanine. These facts suggest that Ser587, Asp675, and His707 are essential residues for the AARE activity and comprise the catalytic triad of the enzyme in this order. Thus, AARE has been shown to have a protease-like domain in its C-terminal region, as do other proteins classified as members of the oligopeptidase family.

Electrostatic stabilization in methionine aminopeptidase from hyperthermophile Pyrococcus furiosus

The thermostability of methionine aminopeptidase from a hyperthermophile P. furiosus (PfMAP) was extremely high: the denaturation temperature was 106.2 degreesC at pH 10.2. To explore the contribution of electrostatic interaction to the superior thermostability of PfMAP, the thermostability of PfMAP was examined by differential scanning calorimetry (DSC) in various salt concentrations in the acidic region far from the isoelectric point of PfMAP. (1) In 20 mM glycine buffer, the DSC curve of PfMAP exhibited a single peak. Transition temperatures (Tm) were lowered with decreasing pH from 4 to 3. The heat denaturation of PfMAP was not reversible. (2) Denaturation enthalpy (DeltaH) measured at different pHs linearly correlated with Tm up to 102 degreesC, suggesting that the denaturation heat capacity (DeltaCp) for PfMAP is constant up to 100 degreesC. DeltaCp was estimated to be 0.82 J K-1 g-1. (3) In the presence of 10-100 mM KCl at pH 3.2, two peaks appeared on the DSC curves. The first peak shifted to lower temperatures with increasing concentration of KCl and, oppositely, the second one to higher temperatures. It was found that the first and second peaks originated from the heat denaturation of the native form of PfMAP and the melting of the non-native associated form having molten globule-like structure, respectively, judged from the CD spectra and ultracentrifugation analyses. This indicates the following: first, the attractive electrostatic interaction is an important factor in stabilizing the native form of PfMAP; second, the presence of KCl stimulates the formation of the molten globule-like state of PfMAP and stabilizes it. (4) In a comparison of the sequence and crystal structure of PfMAP, which has been recently determined (1xgs.pdb), with those of MAP from Escherichia coli (EcMAP), it was predicted that the extra four short-range ion pairs less than 3 A involved in PfMAP are crucial candidates as determinants for the superior thermostability of PfMAP.

Metabolic labeling of a subset of glial cells by UDP-galactose: implication for astrocyte lineage diversity

Astrocytes are implicated in many aspects of brain function; however, it remains unclear whether astrocytes arise from a single cell lineage. It is therefore important to obtain new markers for the astrocyte cell lineage. We show that exogenously added UDP-galactose (UDP-Gal) can be used to metabolically label a subset of glial fibrillary acidic protein-positive (GFAP+) cells. UDP-Gal was incorporated into the cultured embryonic mouse brain slices in a time-dependent manner. Surprisingly, the transferred sugar moiety was no longer Gal but was mainly glucose. Most of the radioactivity was transferred to a polymer of glucose, most likely to be glycogen, and also to glucosyl ceramide. In the slice culture, the reaction products were distributed densely in the ventricular zone and also on process-like structures extending to the pial surface. In dissociation culture, UDP-Gal labeled some of the GFAP+ cells and some of the vimentin+ cells. Because radial glial cells (RGCs) contain glycogen and change from vimentin+ to GFAP+, it is strongly suggested that UDP-Gal labeled RGCs and their descendants. Only 27% of the GFAP+ cells were labeled with UDP-Gal, which suggests that only a subset of astrocytes are derived from RGCs and that there is a discrete group of GFAP+ cells that is not generated from RGCs.

Role of ABC transporters in aureobasidin A resistance

Aureobasidin A (AbA) has strong antifungal effects arising from an unusual mechanism. We show that AbA interacts with ATP-binding cassette (ABC) transporters in yeast and mammalian cells. We isolated a gene of Saccharomyces cerevisiae that conferred resistance to AbA when the gene was present in multiple copies. The gene was identical to YOR1/YRS1, which confers resistance to oligomycin, reveromycin, and organic anions, none of which have structures similar to that of AbA. We also isolated an aur3R recessive mutant of S. cerevisiae with increased resistance to AbA. Northern hybridization showed that the aur3R mutant expressed not only YOR1 but also the ABC transporter-encoding gene PDR5 at high levels. Genetic studies showed that the aur3R mutant had a mutation in the PDR1 gene, which encodes a transcriptional regulator of PDR5 and YOR1. Analysis of a yor1 disruptant of the aur3/pdr1 mutant showed that both the functional YOR1 gene and the mutation in PDR1 were necessary for AbA resistance. These results suggest that YOR1 is more important than PDR5 for AbA resistance. We found in Candida albicans a novel gene whose sequence was similar to the sequence of YOR1 in S. cerevisiae. The amino acid sequence of the C. albicans YOR1 homolog showed no significant similarity to the sequences of CDR1 and CDR2, which are ABC transporters of C. albicans. Furthermore, AbA inhibited the efflux of the anticancer agent vincristine through P glycoproteins in cancer cells with multidrug resistance.

Differential expression of IFN-gamma, IL-4, IL-10, and IL-1beta mRNAs in decalcified tissue sections of mouse lipopolysaccharide-induced periodontitis mandibles assessed by in situ hybridization

To examine the role of T cell subgroups, Th1 and Th2, in the development of periodontitis, the expression of various cytokines was investigated in a mouse model of alveolar bone resorption using in situ hybridization (ISH) with digoxigenin-labeled oligonucleotides. When mice received repetitive injections with Escherichia coli lipopolysaccharide into the gingiva every 48 h, alveolar bone resorption was detectable after the fourth injection, reaching a maximum after the 13th injection. For the best performance of ISH, we first had to choose a decalcification protocol. Among various decalcification protocols, 10% EDTA (4 degrees C, 5-6 days) was the best for 28S rRNA staining. Positive cells for transcripts of interferon-gamma (Th1 product) were detected after the fourth injection, reaching a maximum after the tenth injection. A similar pattern was obtained for interleukin (IL)-10 mRNA (Th2 product) and IL-1beta, while the positive cell number reached a maximum after the 13th and 10th injections, respectively. The number of IL-4 mRNA (Th2 product)-positive cells remained low till the tenth injection, but increased thereafter. Consequently, we found that the population change from Th1 to Th2 in the inflammation site correlated with the transition from gingivitis to periodontitis, indicating differential roles of T cell subgroups in the development of periodontitis.

Transformation system for prototrophic industrial yeasts using the AUR1 gene as a dominant selection marker

We show a new transformation system for prototrophic yeast strains including those of Saccharomyces cerevisiae, Kluyveromyces lactis, K. marxianus, and Candida glabrata. This system is composed of an antibiotic, aureobasidin A (AbA), and its resistance gene AUR1-C as a selection marker. Southern analysis of genomic DNAs of the transformants indicated that the copy number of the plasmid increased from one to more than four, depending on the concentration of AbA used for selection of the transformants. The AUR1-C gene was also effective as a selection marker for gene disruption, and was able to disrupt both copies of the gene on homologous chromosomes of diploid cells by a single round of transformation. This system has a broad application in the transformation and gene disruption of prototrophic strains of a variety of yeast species.

Enzymatic synthesis of a neoglycoconjugate by transglycosylation with Arthrobacter endo-beta-N-acetylglucosaminidase: a substrate for colorimetric detection of endo-beta-N-acetylglucosaminidase activity

The transglycosylation activity of endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae was used for the enzymatic synthesis of a novel oligosaccharide, Man6GlcNAc-p-nitrophenyl-alpha-D-glucose (Man6GlcNAc-Glc-pNP). The reaction was efficiently induced in aqueous solution containing dimethyl sulfoxide. In the medium containing 20% (v/v) dimethyl sulfoxide with 0.1 M Glc-pNP as an acceptor, the transglycosylation attained yields of 75% by high-performance anion-exchange chromatography. The structure of Man6GlcNAc-Glc-pNP was confirmed by ion mass spectrometry and 400 MHz 1H NMR spectrometry. Various endo-beta-N-acetylglucosaminidases hydrolyzed this oligosaccharide and Man6GlcNAc and Glc-pNP were released from the oligosaccharide by endo-beta-N-acetylglucosaminidase digestion. We have established a new procedure for the colorimetric detection of endo-beta-N-acetylglucosaminidase activity using Man6Glc-NAc-Glc-pNP, which is simple as that for other exoglycosidase assays with pNP-glycosides as substrates.

Syntheses of antifungal aureobasidin A analogs with alkyl chains for structure-activity relationship

The syntheses of aureobasidin A (AbA) derivatives with alkyl chains and their in vitro structure-biological activity relationships are discussed. The analogs replaced at positions 6, 7, or 8 of AbA with either L-glutamic acid, delta-hydroxy-L-norvaline, or delta-hydroxy-N-methyl-L-norvaline are prepared. The gamma-carboxyl or delta-hydroxyl group of these new amino acids was coupled with acids, alcohols, or amines with alkyl chains. While the analogs having L-glutamic acid residue at positions 6 or 8 showed weak activity, esterification of the gamma-carboxyl group with benzyl or shorter alkyl (C4 or C6) alcohols, significantly enhanced the activities. Introduction of longer alkyl (C14) chain to the same amino acids residues at positions 6, 7, or 8 resulted in total loss of antifungal activity. Among the lipophilic analogs in [L-Glu6] derivatives, the C6 alcohol ester showed the strongest antifungal activity against Candida spp. so far tested. None of the derivatives showed activity against Cryptococcus neoformans.

Aureobasidins as new inhibitors of P-glycoprotein in multidrug resistant tumor cells

Cyclic depsipeptide antibiotic aureobasidin A (AbA) and its analogs were tested for the inhibitory activity of P-glycoprotein in multidrug resistant cancer cells as well as for the antifungal activity. Some analogs with lower antifungal activity than AbA showed higher inhibition of P-glycoproteins indicating difference of the structure-activity relationships between the two activities. Among AbA analogs tested, [D-beta-hydroxy-methylvalyl9]-AbA newly prepared by chemical synthesis, which had much lower antifungal activity than AbA, showed 10-fold higher inhibitory activity of P-glycoprotein than AbA.

Role of left atrial appendage in left atrial reservoir function as evaluated by left atrial appendage clamping during cardiac surgery

We evaluated the role of left atrial appendage (LAA) in the left atrial (LA) reservoir function by assessing the changes in LA flow dynamics after LAA clamping during cardiac surgery. The subjects were 8 patients who had undergone coronary artery bypass grafting (CABG) and 7 who had undergone mitral valvular surgery due to mitral regurgitation. We recorded transmitral, pulmonary venous and LAA flow velocity patterns by intraoperative transesophageal pulsed Doppler echocardiography, monitoring LA pressure before and 5 minutes after LAA clamping. The maximal LAA area was significantly greater, and the peak late diastolic LAA emptying flow velocity was significantly lower before LAA clamping in the mitral regurgitation group than in the CABG group. In both groups, the peak early and late diastolic transmitral and pulmonary venous flow velocities significantly increased, and the peak second systolic pulmonary flow velocity significantly decreased during LAA clamping. There were no significant changes in heart rate and systemic systolic blood pressure during LAA clamping, whereas mean LA pressure and maximal LA dimension significantly increased in both the groups. The LA pressure-volume relation during ventricular systole shifted upward and to the left during LAA clamping, and the slope was steeper in the MR group than in the CABG group. We conclude that the LAA is more compliant than the LA main chamber, and plays an important role in LA reservoir function in the presence of LA pressure and/or volume overload.

Differential display with carboxy-X-rhodamine-labeled primers and the selection of differentially amplified cDNA fragments without cloning

Differential display (DD) has been used extensively to detect differentially expressed genes. However, the low reproducibility of displayed bands makes verification by Northern blot difficult and the technique is labor-intensive. This report describes a fluorescent DD with a ROX (carboxy-X-rhodamine)-labeled anchor primer and a revised RT-PCR, utilizing AMV reverse transcriptase, a more thermostable reverse transcriptase than Mu-MLV, and optimized concentrations of dNTPs and of MgCl2. Our technique yielded clear fingerprints with high reproducibility. Further, we have developed a method of rapid screening to select the cDNA fragments of interest in excised bands from a polyacrylamide gel without cloning. This method consists of electrophoresis with an agarose gel containing a base-specific DNA ligand to separate the equally sized fragments differing in base composition, and side-by-side comparison of the reamplified products from the experimental and control lane. Most of the cDNA fragments selected by this protocol provided readable sequences by direct sequencing and were confirmed to exhibit differential expression by Northern blot analysis or semiquantitative RT-PCR.

Cyclic ADP-ribose and inositol 1,4,5-trisphosphate as alternate second messengers for intracellular Ca2+ mobilization in normal and diabetic beta-cells

Intracellular Ca2+ mobilization occurs in a variety of cellular processes and is mediated by two major systems, the inositol 1,4, 5-trisphosphate (IP3) and cyclic ADP-ribose (cADPR) systems. cADPR has been proposed to be a second messenger for insulin secretion induced by glucose in pancreatic beta-cells (Takasawa, S., Nata, K., Yonekura, H., and Okamoto, H. (1993) Science 259, 370-373). Here we show that the cADPR signal system for insulin secretion is replaced by the IP3 system in diabetic beta-cells such as ob/ob mouse islets and RINm5F cells. We measured the cADPR content in these beta-cells by radioimmunoassay and found that the increase of the cADPR content by glucose did not occur in ob/ob mouse islets and RINm5F cells, whereas the increased cADPR level by glucose was observed in normal rat and mouse islets. Microsomes of these diabetic beta-cells released Ca2+ in response to IP3 but not to cADPR. In the diabetic beta-cells, CD38 (ADP-ribosyl cyclase/cADPR hydrolase) and type 2 ryanodine receptor mRNAs were scarcely detected and, in contrast, an increased expression of IP3 receptor mRNAs was observed. The diabetic beta-cells secreted insulin rather by carbamylcholine than by glucose.

Transgenic mice overexpressing type 2 nitric-oxide synthase in pancreatic beta cells develop insulin-dependent diabetes without insulitis

We generated transgenic mice carrying the mouse type 2 nitric-oxide synthase (NOS2) cDNA under the control of the insulin promoter. Western and immunohistochemical analyses revealed that NOS2 was expressed abundantly in transgenic islets but not in control islets. When islets were isolated and cultured, high levels of nitrite were released from the transgenic islets. In transgenic mice, the beta cell mass was markedly reduced without the infiltration of macrophages or lymphocytes, and extensive DNA strand breaks were detected in the islets by in situ nick translation. All the transgenic mice developed hypoinsulinemic diabetes by 4 weeks of age, and treatment with an inhibitor of NOS2, aminoguanidine (200 mg/kg body weight every 12 h), prevented or delayed the development of diabetes. The present study shows that the production of nitric oxide by beta cell NOS2 plays an essential role in the beta cell degeneration.

Serum autoantibodies recognizing 5-hydroxymethyl-2'-deoxyuridine, an oxidized DNA base, as biomarkers of cancer risk in women

Human sera contain anti-5-hydroxymethyl-2'-deoxyuridine (HMdU; an oxidized thymidine) autoantibodies (aAbs), which are significantly higher in chronic inflammatory diseases. The intent of this study was to establish whether anti-HMdU aAbs can serve as predictors of breast and colorectal cancer risk. Sera of 169 women were analyzed by ELISA. Women healthy at blood donation but who were diagnosed 0.5-6 years later with breast or colorectal cancer exhibited significantly increased anti-HMdU aAbs over the age-matched controls (P = 0.028 and P < 0.001, respectively). Subjects diagnosed with rectal cancer had the highest levels of anti-HMdU aAbs (44.80 +/- 11.50; n = 6) in comparison to colon (29.03 +/- 2.49; n = 33) and breast (35.86 +/- 8.55; n = 9) cancers. Individuals with benign breast disease also had elevated anti-HMdU aAb (35.12 +/- 8.77; n = 10), with a borderline statistical significance (P = 0.095), whereas those with benign gastrointestinal tract diseases had those titers (30.95 +/- 3.64; n = 8) significantly increased (P < 0.02). Anti-HMdU aAb levels in subjects with a family history of any cancer (23.57 +/- 2.86; n = 55) did not significantly differ from those of the controls (19.41 +/- 2.90; n = 48), but women with a family history of breast cancer (two primary relatives or one with a bilateral disease) showed increased levels (34.48 +/- 8.16; n = 8; P = 0.024). Ps for linear trend of age-adjusted odds ratios were 0.049 for breast and < 0.001 for colorectal cancers. Anti-HMdU aAb titers showed a remarkable stability over a period of 6 years, with a low (14%) intraindividual variance. Thus, elevated anti-HMdU aAb titers may be an early signal of cancer risk, because they were significantly increased in otherwise healthy women who had a family history of breast cancer; in those who had benign breast disease or benign gastrointestinal tract diseases; and, most importantly, in those who at 0.5-6 years after the initial blood donation developed breast or colorectal cancer.

Isolation and characterization of the aureobasidin A-resistant gene, aur1R, on Schizosaccharomyces pombe: roles of Aur1p+ in cell morphogenesis

To study the mechanism of action of the antibiotic aureobasidin A (AbA) on yeasts, we isolated a dominant mutant of Schizosaccharomyces pombe which gave high resistance to AbA. From a genomic library of the mutant, an aur1R mutant gene conferring AbA resistance was isolated. One amino-acid mutation, a substitution of glycine with cysteine at residue 240, was responsible for the acquisition of AbA resistance. The wild-type aur1+ gene was essential for viability, and its over-expression enhanced significant resistance to AbA. The predicted protein of S. pombe aur1R was highly homologous in primary structure and hydropathy profile with that of Saccharomyces cerevisiae AUR1R isolated as an AbA-resistance gene. To analyze a role in cell growth of S. pombe aur1+, temperature-sensitive mutants (aur1ts) were obtained by random mutagenesis procedures using a modified PCR. The aur1ts mutation caused a defect in cell elongation at the non-permissive temperature and finally led to cell death. These results suggest that Aur1p was a target of the antibiotic AbA and was required in the cell elongation of cell-end tips and in the viability of S. pombe.

A novel derivatization method with 5-bromonicotinic acid N-hydroxysuccinimide for determination of the amino acid sequences of peptides

We have developed a novel method that effectively identifies the N-terminal product ions produced in the tandem mass spectrometry (MS/MS) analysis of peptides done in conjunction with the specific derivatization of the N-terminal amino group using 5-bromonicotinic acid N-hydroxysuccinimide ester (BrNA-NHS). Electrospray ionization with low-energy collision-induced dissociation (CID) MS/MS clearly differentiated the N-terminal product ions labeled with the 5-bromonicotinyl group from other ions, on the basis of the appearance of CID peaks with a doublet pattern characteristically separated by 2 mass units produced by the equal natural abundances of 79Br and 81Br. The tracing of a series of these bromine-containing product ions allows the easy amino acid sequencing of peptides. Using Gln-Arg-Leu-Gln-Ser-Asn-Gln-Leu-Lys as the test peptide, we found that within 30 minutes at pH 6.5 and 37 degrees C its alpha-amino group was completely acylated with BrNA-NHS (peptide: BrNA-NHS = 1:40; mol/mol). The epsilon-amino group of the C-terminal lysine residue was less likely to be acylated under these conditions, being only partly modified (about 20%). This suggests the possibility of keeping the epsilon-amino group free from acylation. The method was successfully applied to the determination of the amino acid sequences of peptides from porcine kidney aminoacylase I produced by digestion with lysyl endopeptidase and with Staphylococus aureus V8 protease.

High-resolution crystals of methionine aminopeptidase from Pyrococcus furiosus obtained by water-mediated transformation

The monoclinic crystal form of methionine amino-peptidase from Pyrococcus furiosus (MAP-Pfu) has been crystallized from four different conditions. Native crystals belong to space group P2(1) with typical unit-cell dimensions a = 53.4, b = 85.1, c = 72.7 A, beta = 107.7 degrees and diffract to 2.9-4.5 A resolution. However, there is a problem of nonisomorphism among the crystals. Water-mediated transformation to low-humidity form occurs by reduction of the relative humidity of crystal environment to 79%. The unit-cell dimensions of transformed crystals are a = 51.9, b = 83.3, c = 70.3 A, beta = 105.9 degrees, and the calculated solvent content is 3.9% less than in original crystals. Transformation to low-humidity form is accompanied by 1.7 times reduction of overall temperature factors, extension of diffraction resolution up to 1.75 A, without change or reduction of crystal mosaicity, and improvement in stability to X-ray radiation. The water-mediated transformation also appears to relieve the problem of nonisomorphism among the original MAP-Pfu crystals.

Optimization of fibronectin-assisted retroviral gene transfer into human CD34+ hematopoietic cells

Efficient retroviral gene transfer into hematopoietic stem and progenitor cells can be achieved by co-localizing retrovirus and target cells on specific adhesion domains of recombinant fibronectin (FN) fragments. In this paper, we further optimize this technology for human CD34+ cells. Investigating the role of cytokine prestimulation in retrovirus-mediated gene transfer on plates coated with the recombinant FN CH-296 revealed that prestimulation of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood (PB) CD34+ cells was essential to achieve efficient gene transfer into clonogenic cells. The highest gene transfer occurred by prestimulating PB CD34+ cells for 40 hr with a combination of stem cell factor (SCF), G-CSF, and megakaryocyte growth and development factor (MGDF) prior to retroviral infection on CH-296. Surprisingly, a prolonged simultaneous exposure of primary CD34+ PB cells to retrovirus and cytokines in the presence of CH-296 lowered the gene transfer efficiency. Gene transfer into cytokine prestimulated CD34+ bone marrow (BM) cells was not influenced by increasing the coating concentrations of a recombinant FN fragment, CH-296, nor was it adversely influenced by increasing the number of CD34+ target cells, suggesting that the amount of retroviral particles present in the supernatant was not a limiting factor for transduction of CD34+ BM cells on CH-296-coated plates. The polycation Polybrene was not required for efficient transduction of hematopoietic cells in the presence of CH-296. Furthermore, we demonstrated that repeated exposure of CH-296 to retrovirus containing supernatant, called preloading, can be employed to concentrate the amount of retroviral particles bound to CH-296. These findings establish a simple and short clinically applicable transduction protocol that targets up to 68% of BM or G-CSF-mobilized PB CD34+ cells and is capable of genetically modifying up to 17% of CD34+CD38-/dim PB cells.

Fibronectin fragment-facilitated retroviral transfer of the glutathione-S-transferase pi gene into CD34+ cells to protect them against alkylating agents

To protect bone marrow cells from the toxicity of chemotherapy, a multidrug resistant gene or a dihydrofolate reductase gene has been introduced into stem cells. These genes, however, are not capable of conferring refractoriness to alkylating agents (AA), which are some of the most commonly used agents in chemotherapy regimens. In the present study, an attempt was made to endow human stem cell (CD34+ cells) with resistance to cyclophosphamide, a well-known AA, and adriamycin (ADM) by transducing the glutathione-S-transferase pi (GST-pi) gene whose product is thought to detoxify AA by conjugating them with glutathione and to remove a toxic peroxide formed by ADM. The gene transduction was carried out retrovirally with a virus titer of 1 x 10(5) FFU/ml, employing a recombinant fibronectin fragment; transduction efficiency was extremely low without the fragment. Incubation with interleukin-6 and stem cell factor enhanced the expression of fibronectin ligands VLA4 and VLA5 on CD34+ cells. This enhanced expression of VLA4 and VLA5 was considered to facilitate a close contact of the CD34+ cell to the retroviral vector via fibronectin fragments and the subsequent transduction process. The GST-pi gene-transduced CD34+ cells formed almost 3- and 2.5-fold more CFU-GM than neo gene-transduced CD34+ cells in the presence of 2.5 microg/ml of 4-hydroperoxycyclophosphamide (4-HC), an active form of cyclophosphamide, and 30 ng/ml ADM, respectively. The transfectants formed an appreciable number of colonies, even at higher concentrations of these drugs (5.0 microg/ml of 4-HC, 50 ng/ml of ADM) whereas neo gene-transduced or nontransduced CD34+ cells formed no colonies at all, indicating the possibility of selecting out the transfectants by exposing them to these anticancer drugs. Thus, we were able to demonstrate that transduction of the GST-pi gene confers resistance to cyclophosphamide as well as to ADM, and therefore this approach can be applied clinically for high-dose chemotherapy.

[Effect of body mass index on morbidity and mortality in a general Japanese population--the Hisayama study]

In order to investigate the effect of body mass index (BMI, kg/m2) on life expectancy, 2053 Hisayama residents, aged 40 years or older were studied for 13 years from 1974. During the follow-up period, 419 subjects died; of these, 39 deaths due to accident or suicide were excluded from further analysis. On initial examination, male subjects with BMI > or = 27 had significantly higher age-adjusted prevalence rates of hypertension, glucose intolerance, hypercholesterolemia, electrocardiogram abnormalities and proteinuria, as compared with those with 23-25 BMI. In contrast, the frequency of male smokers was inversely associated with BMI levels. Female prevalence rates of glucose intolerance, hypercholesterolemia and proteinuria were significantly higher in 25-27 BMI than in 23-25. Body Mass Index showed a U-shaped relationship with all cause mortality rates with the lowest rate in 23-27 BMI for men and in 23-25 BMI for women. These associations remained substantially unchanged, even after controlling for age, systolic blood pressure, glucose intolerance, serum cholesterol, proteinuria, electrocardiogram abnormalities, alcohol consumption, and smoking habits. When analyzing the BMI mortality relationship by cause of death, age- and sex-adjusted mortality rates from myocardial infarction and stroke significantly increased in subjects with BMI > or = 27 compared with those with 23-25 BMI. In contrast, there was a decreasing risk of death from malignant neoplasms with rising BMI levels, but the relationship was not significant. Mortality from pneumonia and other causes showed a U-shaped relationship with significantly higher rates seen in BMI < 19 than in 23-25 BMI. These data indicate that BMI has a U-shaped relationship with total mortality in the general Japanese population, which results from various associations between BMI and cause-specific mortality rates.

Prospective study of diet and female colorectal cancer: the New York University Women's Health Study

The relation between diet and female colorectal cancer was analyzed in a prospective study of 14,727 women aged 34-65 years, who were enrolled at mammographic screening clinics in New York and Florida from 1985 to 1991. They were followed through the end of 1994 (average 7.1 yrs) by a combination of direct contact through mail and telephone and record linkages with regional tumor registries, resulting in 100 incident cases of colorectal cancer. There was no overall positive or inverse association of colorectal cancer risk with intakes of total calories, total or subclasses of fat, carbohydrate, or dietary fiber, whereas there was an inverse association with total protein. Among major food groups, there was a progressive decline in risk of colorectal cancer with increasing intake of fish and shellfish (relative risk for 4th vs. 1st quartile = 0.49, 95% confidence interval = 0.27-0.89). A similar inverse association was also observed for consumption of dairy products, and this association was explained mainly by calcium, not by other nutrients, such as fat or protein. The results of the present study indicated that certain dietary components of fish or dairy products may protect against colorectal cancer, whereas the relations with red meat or total fat remained unclear.

Methionine aminopeptidase from the hyperthermophilic Archaeon Pyrococcus furiosus: molecular cloning and overexpression in Escherichia coli of the gene, and characteristics of the enzyme

A gene for a methionine aminopeptidase (MAP; EC 3.4.11.18), which catalyzes the removal of amino-terminal methionine from the growing peptide chain on the ribosome, has been cloned from the hyperthermophilic Archaeon, Pyrococcus furiosus, by a novel method effectively using its cosmid protein library, sequenced and expressed in Escherichia coli. The DNA sequence encodes a protein containing 295 amino acid residues with methionine at the N-terminus. From protein analyses of the recombinant protein expressed in E. coli, by using both amino acid sequence analysis from the N-terminus by automated Edman degradation and analyses of molecular masses of the peptides generated by two enzymatic cleavages performed independently, digestions with lysylendopeptidase and Endoproteinase Asp-N, with ionspray mass spectrometry, the primary structure of the protein has been elucidated to be completely identical with that deduced from its DNA sequence. Comparison of the amino acid sequence of P. furiosus MAP (P.f. MAP) with those of other MAPs from Eukarya and Bacteria showed that the protein has a high degree of sequence homology in the stretches surrounding the five cobalt-binding residues fully preserved in all of MAPs determined so far, but P.f. MAP belongs to Type II because it has an extra long insertion of about 60 amino acid residues between the fourth and fifth cobalt-binding ligands, similar to MAPs from human and rat, and to Met-AP2 from Saccharomyces cerevisiae, in comparison to Type I MAPs from Bacteria. Therefore, P.f. MAP seems to be rather close to those from Eukarya, although it is distinct in lacking the N-terminal extension of about 90-150 residues universally found in MAPs from Eukarya. These findings suggest that P.f. MAP is evolutionally located at the Eukarya-Bacteria boundary. The enzyme expressed in E. coli exhibits a considerable thermostability, with a half-life of approximately 4.5 h at 90 degrees C and an optimum temperature of around 90 degrees C.

Effects of fibronectin fragments on DNA transfection into mammalian cells by electroporation

Two kinds of cells, human epidermoid carcinoma A431 cells and simian kidney COS-7 cells, were transfected with the chloramphenicol acetyl transferase (CAT) gene by electroporation, and then cultivated on culture dishes coated with two different forms of recombinant fibronectin fragments consisting of cell-binding domain (C-274) or heparin-binding domain and CS1 region (H-296). In the case of A431 cells, H-296-coated dishes significantly increased the amount of expressed CAT and the adhesion of electroporated cells in comparison with non-coated dishes. C-274 was effective for COS-7 cells. Overall, these fibronectin fragments increased the recovery of the transfectants on A-431 cells and COS-7 cells, respectively.

[The serum zinc level in patients with tinnitus and the effect of zinc treatment]

We measured the serum zinc level in patients with tinnitus and evaluated the effectiveness of zinc in the treatment of tinnitus. Blood zinc levels were measured in 121 patients with tinnitus. All patients were examined between 1995 and 1997 at the outpatient clinic of otorhinolaryngology St. Marianna University Toyoko Hospital. Forty-seven patients who had received any drug such as a calcium channel blocker and others or had been affected by any diseases were excluded and therefore 74 patients consisting of 46 females (62%) and 28 males (38%) were investigated. Twenty two healthy volunteers served as a control group. The mean age and standard deviations for the tinnitus group and the control group were 47.8 +/- 17.1 and 31.4 +/- 8.2 years, respectively. There was a significant decrease (p < 0.0001) in serum zinc levels in patients with tinnitus compared with the control group. Because there was a significant difference (p < 0.0001) in age distribution between tinnitus and control groups, patients were selected by their age in order to neglect the effect of aging. In this situation, a significant difference (p < 0.01) was noted between the tinnitus group and control group. Low blood zinc level was defined by using the mean and standard deviation for the control group (mean-1 S.D.). We treated patients with low blood zinc levels. A total dose of 34-68 mg of Zn++ was administered daily for over 2 weeks. The degree of tinnitus was expressed on a numeric scale from 0 to 10 before and after treatment. Blood zinc levels were significantly elevated (p < 0.05) after treatment. We found a significant decrease (p < 0.01) in the numeric scale. These findings suggest that zinc is useful in at least some patients suffering from tinnitus. It is possible to classify patients with tinnitus by measuring serum zinc level and this leads to improvement of the overall treatment effect.

Extracellular 37-kDa antigenic protein from Actinobacillus actinomycetemcomitans induces TNF-alpha, IL-1 beta, and IL-6 in murine macrophages

The extracellular antigens of Actinobacillus actinomycetemcomitans Y4 (serotype b) contain a 37-kDa protein which is a major target for IgGs from patients suffering from severe alveolar bone loss. Since the 37-kDa protein has not been studied sufficiently, our investigation focused on its characteristics, e.g., its localization, specificity, and whether it directly stimulates macrophages to produce cytokines. The 37-kDa protein was purified from the culture supernatant of the Y4 strain by means of chromatofocusing and gel filtration. The 37-kDa protein is a unique glycoprotein which forms immune complexes with monoclonal antibodies against rhamnose-fucose polysaccharide. Patients with A. actinomycetemcomitans-associated periodontitis had higher antibody titers to the purified 37-kDa protein than healthy subjects (p < 0.001). Anti-37-kDa protein antibodies recognized a 37-kDa band in the cytosolic, ribosomal, and total membrane fractions from Y4 cells. Extracellular substances from other strains of A. actinomycetemcomitans (serotypes a and c) also reacted in the Western blots, but Haemophilus spp. or several periodontopathic bacteria did not. These results suggested that the 37-kDa protein is a cytosolic protein that is passed through the cell membrane, and its protein portion is specific for A. actinomycetemcomitans but common to serotypes. This protein induced Il-1 beta, Il-6, and TNF-alpha release from murine macrophages. The Il-6-inducing activity of the 37-kDa protein was higher than that of LPS. These findings suggested that the 37-kDa protein which is released from live cells plays a role in A. actinomycetemcomitans-associated periodontitis, as antigen inducing the release of inflammatory cytokines which are associated with alveolar bone loss.

Distribution of anandamide amidohydrolase in rat tissues with special reference to small intestine

Anandamide (arachidonylethanolamide), an endogenous ligand for cannabinoid receptors, is hydrolyzed by an amidohydrolase and its biological activity is lost. Previously, we partially purified the enzyme from porcine brain and anandamide synthesis by its reverse reaction was proposed (Ueda et al., (1995) J. Biol. Chem. 270, 23823-23827). The anandamide hydrolase and synthase activities were examined with various rat tissues. Rat liver showed the highest specific activities (4.4 +/- 0.3 and 4.5 +/- 0.5 nmol/min/mg protein) for the hydrolase and synthase, respectively. In most other tissues such as brain, testis and parotid gland, the ratio of synthase/hydrolase activity was 0.7-1.6. However, small intestine showed a relatively high synthase/hydrolase ratio of about 5.0 (1.0 +/- 0.1 and 0.2 +/- 0.1 nmol/min/mg protein). When a homogenate of small intestine was subjected to acetone extraction to remove lipids, a higher hydrolase activity was found (2.0 +/- 0.2 nmol/min/mg protein). Furthermore, Northern blotting detected an intense mRNA band of anandamide hydrolase in small intestine as well as liver and brain. These results demonstrated for the first time a high content of anandamide hydrolase in small intestine.

Molecular cloning, expression, and sequence analysis of the endoglycoceramidase II gene from Rhodococcus species strain M-777

Endoglycoceramidase (EGCase (EC 3.2.1.123)) is a hydrolase that hydrolyzes the linkage between the oligosaccharide and ceramide of various glycosphingolipids. This paper describes the molecular cloning and expression of EGCase II, one of the isoforms of EGCases. The gene encoding EGCase II was obtained by screening of a genomic DNA library from Rhodococcus sp. strain M-777 constructed in pUC19 with oligonucleotide probes deduced from a partial amino acid sequence of the enzyme protein. Recombinant Escherichia coli cells in which the EGCase II gene was expressed produced 14 units of the enzyme per liter of culture medium but did not produce sphingomyelinase. Recombinant EGCase II was a functioning enzyme with substrate specificity identical to that of the wild-type enzyme. Sequence analysis showed the presence of an open reading frame of 1470 base pairs encoding 490 amino acids. The N-terminal region of the deduced amino acid sequence had the general pattern of signal peptides of secreted prokaryotic proteins. Interestingly, the consensus sequence in the active site region of the endo-1,4-beta-glucanase family A was found in the amino acid sequence of EGCase II.

Prevention of onset in an insulin-dependent diabetes mellitus model, NOD mice, by oral feeding of Lactobacillus casei

The effect of Lactobacillus casei (LC) on the onset of diabetes in an insulin-dependent diabetes mellitus model, nonobese diabetic (NOD) mice, were examined. From the age of 4 weeks, female NOD mice were fed a diet of either standard laboratory chow (n = 12) or the same chow containing 0.05% weight heat-killed cells of LC (n = 12), and the onset of diabetes was thereafter recorded. The incidence of diabetes in the control group (10/12) was significantly higher than that in the LC-treated group (3/12) (p < 0.01). Pathological analysis in the LC-treated group revealed strong inhibition of the disappearance of insulin-secreting beta cells in Langerhans islets caused by autoimmune disease. The proportion of CD45R+ B-cells in the spleen was increased and that of CD8+ T-cells in spleen cells was decreased in the LC-treated group. Analysis of cytokine production revealed lower interferon-gamma production in the LC-treated group compared to the control group, while the interleukin (IL)-2 production was higher. The levels of IL-4, IL-5, IL-6 and IL-10 in the LC-treated group were somewhat higher than in the control group. Taken together, these findings clearly demonstrated that oral feeding of LC to NOD mice effectively inhibited the occurrence of diabetes and regulated the host immune response.

A novel DNA polymerase in the hyperthermophilic archaeon, Pyrococcus furiosus: gene cloning, expression, and characterization

BACKGROUND

In many respects Archaea are much more like eukaryotes than prokaryotes with respect to the conservation of many of the components involved in transcription, translation and DNA replication. So far, only a few DNA polymerases with structures similar to those of eukaryotic DNA polymerase a have been found in Archaea. The identification and characterization of all the DNA polymerases of one archaeon would add considerably to our knowledge of the basic mechanisms of DNA replication in these organisms.

RESULTS

We have identified a novel DNA polymerase composed of two proteins, DP1 and DP2, with molecular weights of 69294 Da and 143161 Da, respectively, in the hyperthermophilic archaeon, Pyrococcus furiosus, and have cloned the corresponding genes which are tandemly arranged on the Pyrococcus genome. No significant sequence homology was found between these two proteins and other known DNA polymerases. The pol genes were transcribed as part of a single operon that additionally contained genes homologous to the cdc18+/CDC6 and Dmc1/Rad51 family of proteins. We purified the Pyrococcus DNA polymerase from Escherichia coli strains expressing the cloned genes and characterized its activity. It possesses strong 3' --> 5' exonucleolytic activity and has a template-primer preference which is characteristic of a replicative DNA polymerase.

CONCLUSION

In P. furiosus, we identified a second DNA polymerase encoded by two genes, neither of which display significant homology to any other known DNA polymerase. Both the enzymatic properties of the enzyme and the gene organization raise the possibility that this enzyme might be the replicative DNA polymerase of P. furiosus.

Dietary and lifestyle correlates of passive smoking in Hong Kong, Japan, Sweden, and the U.S.A

From epidemiologic studies in several countries, passive smoking has been associated with increased risk for lung cancer, respiratory diseases, and coronary heart disease. Since the relative risks derived from those studies are weak, i.e. relative risk less than two, we investigated whether poorer diets and less healthy lifestyles might act as confounders and be correlated with having a smoking husband on a cross-cultural basis. Characteristics of never-smoked wives with or without smoking husbands were compared between 530 women from Hong Kong, 13,047 from Japan, 87 from Sweden, and 144 from the U.S. In all four sites, wives with smoking husbands generally ate less healthy diets. They had a tendency to eat more fried food but less fruit than wives with nonsmoking husbands. Other healthy traits, e.g. avoiding obesity, dietary cholesterol and alcohol, or taking vitamins and participating in preventive screening were also less prevalent among wives with smoking husbands. These patterns suggest that never-smoked wives with smoking husbands tend to share the same less healthy dietary traits characteristic of smokers, and to have dietary habits associated with increased risk for lung cancer and heart disease in their societies. These results emphasize the need to take into account the potential confounding effects of diet and lifestyle in studies evaluating the health effects of passive smoking, especially since it is known that the current prevalence rates of smoking among men is indirectly associated with social class and education in affluent urban societies.

Attenuation of nitric oxide synthase induction in IRF-1-deficient glial cells

Nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) exerts inhibitory and cytotoxic effects on various cells including neuronal cells. Glial NO production, mediated via induction of iNOS, is thought to facilitate neuronal damage during cerebral ischemia. Recently, interferon regulatory factor-1 (IRF-1) has been reported to be an essential transcription factor for iNOS mRNA induction in murine macrophages. However, expression of IRF-1 and its role in the central nervous system have not been examined. In the present study, by using primary glial cell cultures from mice with targeted disruption of the IRF-1 gene, we investigated whether IRF-1 is involved in iNOS mRNA induction in glial cells. After stimulation with lipopolysaccharide and interferon-gamma, IRF-1 mRNA was strongly induced in wild-type (IRF-1 +/+) glial cells. iNOS mRNA induction and nitrite production in IRF-1 -/- glial cells were reduced as compared with those observed in IRF-1 +/+ glial cells. Diethyldithiocarbamate, a selective inhibitor of nuclear transcription factor kappa B (NF-kappa B), completely inhibited iNOS mRNA induction. These results suggest that not only NF-kappa B but also IRF-1 play important roles in iNOS mRNA induction in the central nervous system.

Transgenic copper/zinc-superoxide dismutase ameliorates caerulein-induced pancreatitis in mice

The role of oxidative stress in acute pancreatitis was investigated by comparing the pathological features of caerulein pancreatitis between transgenic mice that overexpress human Cu/Zn-superoxide dismutase (SOD) and nontransgenic littermates. Both the elevation of serum amylase and the formation of pancreatic edema during the pancreatitis were significantly reduced in the transgenic mice compared with the nontransgenic littermates. In the transgenic mice, the pancreatitis-associated reduction of Cu/Zn-SOD activity in the pancreatic tissues was significantly smaller than that in the nontransgenic mice. These results provide direct evidence that the elevation of intracellular oxygen radicals is an important factor for the progress of acute edematous pancreatitis.

A high-density STS map based on a single contig of YAC and P1 clones in the chromosome 8p12-p21 region

We have constructed a yeast artificial chromosome (YAC) and P1 contig in the 8p12-p21 region. The contig comprises 16 overlapping YAC clones and 44 overlapping P1 clones. Twelve dinucleotide-repeat polymorphic sequence-tagged site (STS)-markers that were previously isolated mainly from these YAC and P1 clones were genetically mapped. A total of 46 nonpolymorphic STS markers were newly established mainly from the YAC and P1 clone end fragments, and 28 of the 46 nonpolymorphic STSs, as well as the 12 polymorphic STSs, were also mapped physically onto the contig based on STS content analysis of YAC pools and of the P1 and YAC clones. As a result, the YAC and P1 clones were assembled into a single contig covering a minimum of 1.5 Mb physically and 2.8 cM genetically with 12 polymorphic and 28 nonpolymorphic STSs within the 8p12-p21 region. Average STS spacing in the contig was estimated to be 40 kb/STS. In addition, further characterization of the contig suggested that this contig includes a region where genetic recombination occurs frequently. Thus, the resulting cloned region, together with densely mapped STS markers on the contig, should help to promote our understanding of this region.

Secretion of IL-1 beta, TNF-alpha, IL-8 and IL-1ra by human polymorphonuclear leukocytes in response to lipopolysaccharides from periodontopathic bacteria

Polymorphonuclear leukocytes (PMN) are the first cells that migrate into periodontal tissues and gingival crevices in response to invading pathogens. It was recently demonstrated that PMN have the ability to synthesize and release cytokines following appropriate stimulation, while it is not clear whether these capacities are directly related to periodontal destructive processes. We therefore investigated the amounts of the cytokines interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF-alpha), IL-8 and IL-1 receptor antagonist (IL-1ra) secreted by PMN from healthy donors following stimulation with lipopolysaccharide (LPS) from 4 periodontopathic bacteria, Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Capnocytophaga ochracea and Fusobacterium nucleatum, and the non-oral bacterium Escherichia coli. A actinomycetemcomitans, F. nucleatum and E. coli LPS stimulated the release of significantly greater amounts of IL-1 beta, TNF-alpha and IL-8 than the control unstimulated PMN (p < 0.01). The levels of IL-1 beta, TNF-alpha and IL-8 released from cells stimulated with P. gingivalis or C. ochracea LPS were significantly lower than those of cells stimulated with A. actinomycetemcomitans or E. coli LPS (p < 0.05). On the other hand, substantially greater amounts of IL-1ra were released from PMN stimulated with each LPS and from control unstimulated PMN during the first 6 h, and then significantly greater amounts of IL-1ra were secreted by PMN stimulated with A. actinomycetemcomitans and E.coli LPS during the following 12 h (p < 0.01). The inhibitory effects of IL-1ra on the biological activity of IL-1 in the supernatants of PMN were examined by the thymocyte comitogen proliferation assay. The supernatants of PMN stimulated with each LPS showed less biological IL-1 activity as compared with the same doses of recombinant human IL-1 beta detected by enzyme-linked immunosorbent assay. Furthermore, no activity was detected in the supernatants of PMN stimulated with P. gingivalis or C. ochracea LPS. These findings demonstrated that LPS from periodontopathic bacteria were capable of stimulating PMN to release not only pro-inflammatory cytokines but also their inhibitors such as IL-1ra. Different secretion levels of these cytokines and their biological activities induced by the various LPS might be important in the onset and progression of periodontal diseases.

Fungicidal action of aureobasidin A, a cyclic depsipeptide antifungal antibiotic, against Saccharomyces cerevisiae

Aureobasidin A, an antifungal antibiotic inhibiting a wide range of pathogenic fungi, is lethal for growing cells of susceptible fungi. We did cytological studies on the mechanism of its fungicidal action against Saccharomyces cerevisiae. When cultures were treated with 5.0 micrograms of aureobasidin A per ml, the numbers of viable cells started to decrease after 2 to 3 h of incubation, and most cells had lost viability after 5 to 6 h. When cell death in the treated cultures began, amino acids released by the cells could be detected, indicating disruption of the cell membrane. The proportion of cells with a single small bud or two or more buds increased as the population of viable cells decreased. Most such cells had the DNA content of cells in the G2 phase of the cell cycle, suggesting that the drug inhibited some cellular process involved in normal bud growth but did not affect DNA replication. Disruption of actin assembly was found in many cells treated for 2 to 3 h, as was chitin delocalization. The results suggest that aureobasidin A has a previously unknown mechanism of fungicidal action toward S. cerevisiae. It causes aberrant actin assembly, inhibiting the normal budding process and leading to cell death, probably through destruction of membrane integrity.

Cyclic ADP-ribose binds to FK506-binding protein 12.6 to release Ca2+ from islet microsomes

Cyclic ADP-ribose (cADPR) is a second messenger for Ca2+ mobilization via the ryanodine receptor (RyR) from islet microsomes for insulin secretion (Takasawa, S., Nata, K., Yonekura, H., and Okamoto, H. (1993) Science 259, 370-373). In the present study, FK506, an immunosuppressant that prolongs allograft survival, as well as cADPR were found to induce the release of Ca2+ from islet microsomes. After islet microsomes were treated with FK506, the Ca2+ release by cADPR from microsomes was reduced. cADPR as well as FK506 bound to FK506-binding protein 12.6 (FKBP12.6), which we also found occurs naturally in islet microsomes. When islet microsomes were treated with cADPR, FKBP12.6 dissociated from the microsomes and moved to the supernatant, releasing Ca2+ from the intracellular stores. The microsomes that were then devoid of FKBP12.6 did not show Ca2+ release by cADPR. These results strongly suggest that cADPR may be the ligand for FKBP12.6 in islet RyR and that the binding of cADPR to FKBP12.6 frees the RyR from FKBP12.6, causing it to release Ca2+.

Cloning, sequencing, and expression of Arthrobacter protophormiae endo-beta-N-acetylglucosaminidase in Escherichia coli

The gene encoding endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae (Endo-A) was cloned, and its nucleotide sequence was determined. A single open reading frame consisting of 1935 base pairs and encoding a polypeptide composed of signal peptides of 24 amino acids and a mature protein of 621 amino acids was found. The primary structure of Endo-A exhibited significant homology with FO1F.10 gene product from Caenorhabditis elegans and weak homology with peptide-N4-(N-acetyl-beta-D-glucosaminyl)asparagine amidase from Flavobacterium meningosepticum and chitinase from Streptomyces olivaceoviridis. However, the enzyme had no significant homology with any previously reported endo-beta-N-acetylglucosaminidases. Transformed Escherichia coli cells carrying the 4.5-kb fragment expressed Endo-A activity. This enzyme activity was detected in the medium as well as in the periplasmic space of cells under the control of the Endo-A gene promoter. The recombinant Endo-A was efficiently isolated from the periplasmic space of the cells. N-terminal sequence analysis revealed that native and recombinant Endo-A have the same N-terminus. Recombinant and native Endo-A also showed very similar optimum pH profiles and transglycosylation activity.

Immunohistochemical study of cathepsin G and medullasin in inflamed gingival tissues from periodontal patients

Cathepsin G and medullasin are 2 major serine proteinases associated with the granular fraction of polymorphonuclear leukocytes (PMNs). To know their possible involvement in the pathophysiological gingival connective tissue turnover, we have determined the distribution and localization of these 2 enzymes in inflamed gingival tissues from periodontal patients by immunohistochemistry with discriminating antibodies specific for each enzyme. The gingival connective tissues were obtained from periodontitis patients with various inflammatory conditions and control healthy subjects without any clinical signs of periodontal inflammation. In all gingival specimens examined, cathepsin G and medullasin were found mainly in neutrophil-like cells and partly in macrophage-like cells. No positive staining for both enzymes was obtained in endothelial cells and fibroblasts in every part of the gingival tissues. Immunoreactivity for each enzyme in the gingival tissues from the periodontitis group was stronger and greater in the intensity and frequency than that from the control group and appeared to be increased with the severity of the disease In both groups, the number of immunoreactive cells for each enzyme was greater in the vicinity of pocket epithelium (zone I) than in the area of central connective tissue (zone II) or the area subjacent to the oral epithelium (zone III). While both enzymes in zones II and III were exclusively found in coarse granules, their stainings in zone I were not only coarse but also diffuse. These results strongly suggest that both enzymes may have some association with inflamed gingival tissue degradation.

Histochemical study of the influence of transplanted teeth with periodontal ligament of the binding of peanut agglutinin in rat dorsal skin

Our previous study showed that the expression of carbohydrate residues in junctional epithelium (JE) after resection is closely related to attachment and stratification along the dental root surface. However, the influence of the periodontal ligament on carbohydrate expression has still not been clarified. In this study we examined the relationship between the presence of periodontal ligament and the expression of carbohydrate residues on epithelium regenerating along root surfaces. We transplanted extracted rat molars with or without periodontal ligament tissue, repeatedly frozen and thawed teeth with ligament and demineralized teeth without ligament into the dorsal skin of rats. After 2, 3, 5, 7, 10, 14 or 21 d, dorsal cutaneous tissues containing transplanted teeth were resected, fixed, decalcified and embedded in paraffin. Serial sections were stained histochemically with the HRP-conjugated lectin, peanut agglutinin (PNA) to observe the expression of carbohydrate residues in regenerating epithelium. Histochemical observation revealed that lectin binding reactions were changed from the characteristics of skin to those of JE when the regenerating epithelium was attached and stratified along the tooth with unfrozen or frozen tissue. These results suggested that the structural formation and expression of PNA in regenerating epithelium around the root surface were influenced by not only the tooth but also by the periodontal ligament.