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1.
Br J Cancer ; 110(4): 831-41, 2014 Feb 18.
Article in English | MEDLINE | ID: mdl-24335923

ABSTRACT

BACKGROUND: To systematically review the effects of interventions to improve exercise behaviour in sedentary people living with and beyond cancer. METHODS: Only randomised controlled trials (RCTs) that compared an exercise intervention to a usual care comparison in sedentary people with a homogeneous primary cancer diagnosis, over the age of 18 years were eligible. The following electronic databases were searched: Cochrane Central Register of Controlled Trials MEDLINE; EMBASE; AMED; CINAHL; PsycINFO; SportDiscus; PEDro from inception to August 2012. RESULTS: Fourteen trials were included in this review, involving a total of 648 participants. Just six trials incorporated prescriptions that would meet current recommendations for aerobic exercise. However, none of the trials included in this review reported intervention adherence of 75% or more for a set prescription that would meet current aerobic exercise guidelines. Despite uncertainty around adherence in many of the included trials, the interventions caused improvements in aerobic exercise tolerance at 8-12 weeks (SMD=0.73, 95% CI=0.51-0.95) in intervention participants compared with controls. At 6 months, aerobic exercise tolerance is also improved (SMD=0.70, 95% CI=0.45-0.94), although four of the five trials had a high risk of bias; hence, caution is warranted in its interpretation. CONCLUSION: Expecting the majority of sedentary survivors to achieve the current exercise guidelines is likely to be unrealistic. As with all well-designed exercise programmes, prescriptions should be designed around individual capabilities and frequency, duration and intensity or sets, repetitions, intensity of resistance training should be generated on this basis.


Subject(s)
Exercise , Health Behavior , Health Promotion , Neoplasms/rehabilitation , Sedentary Behavior , Breast Neoplasms/rehabilitation , Colorectal Neoplasms/rehabilitation , Female , Humans , Male , Prostatic Neoplasms/rehabilitation , Randomized Controlled Trials as Topic , Survivors/psychology
2.
BMJ Open ; 3(7)2013.
Article in English | MEDLINE | ID: mdl-23833146

ABSTRACT

INTRODUCTION: Prevalence of non-communicable diseases (NCDs) is increasing globally, with the greatest projected increases in low-income and middle-income countries. We sought to quantify the proportion of Cochrane evidence relating to NCDs derived from such countries. METHODS: We searched the Cochrane database of systematic reviews for reviews relating to NCDs highlighted in the WHO NCD action plan (cardiovascular, cancers, diabetes and chronic respiratory diseases). We excluded reviews at the protocol stage and those that were repeated or had been withdrawn. For each review, two independent researchers extracted data relating to the country of the corresponding author and the number of trials and participants from countries, using the World Bank classification of gross national income per capita. RESULTS: 797 reviews were analysed, with a reported total number of 12 340 trials and 10 937 306 participants. Of the corresponding authors 90% were from high-income countries (41% from the UK). Of the 746 reviews in which at least one trial had met the inclusion criteria, only 55% provided a summary of the country of included trials. Analysis of the 633 reviews in which country of trials could be established revealed that almost 90% of trials and over 80% of participants were from high-income countries. 438 (5%) trials including 1 145 013 (11.7%) participants were undertaken in low-middle income countries. We found that only 13 (0.15%) trials with 982 (0.01%) participants were undertaken in low-income countries. Other than the five Cochrane NCD corresponding authors from South Africa, only one other corresponding author was from Africa (Gambia). DISCUSSION: The overwhelming body of evidence for NCDs pertains to high-income countries, with only a small number of review authors based in low-income settings. As a consequence, there is an urgent need for research infrastructure and funding for the undertaking of high-quality trials in this area.

3.
Caries Res ; 38(4): 341-9, 2004.
Article in English | MEDLINE | ID: mdl-15181333

ABSTRACT

The hypotheses that raw fruits, whether whole or pulped, were cleared rapidly from the mouth and that the sugars in the whole and pulped fruits are fermented with equal efficiency to acids by the oral microflora were tested in this study. Groups of 7-9 adult subjects chewed 10 g of raw, whole or pulped fruit (apple, banana, orange, pear and pineapple) for 1 min and whole, unstimulated saliva samples were collected during the following 60-min interval. Each saliva sample was assayed for the concentrations of fruit-derived sugars (glucose, fructose and sucrose), fruit-derived acids (malic and citric) and acids which may be produced as a result of bacterial fermentation (acetic, lactic, formic and succinic). We found the fruit-derived sugars were rapidly cleared from the mouth (within 5 min). The major bacterially produced acids were lactic and succinic, which reached maximum concentrations in the 5-min sample. There was no significant difference, within a fruit, in the salivary levels of any of the sugars or acids between the raw whole or raw pulped forms. In light of these findings it seems unwise to assume that fruits may be consumed without consideration of their acidogenic potential.


Subject(s)
Carboxylic Acids/metabolism , Cariogenic Agents/metabolism , Dietary Carbohydrates/metabolism , Fruit/metabolism , Saliva/metabolism , Acetic Acid/metabolism , Adult , Bacteria/metabolism , Citric Acid/metabolism , Food Handling , Formates/metabolism , Humans , Lactic Acid/metabolism , Malates/metabolism , Metabolic Clearance Rate , Succinic Acid/metabolism
4.
Appl Environ Microbiol ; 67(8): 3396-405, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11472910

ABSTRACT

Streptococcus oralis is the predominant aciduric nonmutans streptococcus isolated from the human dentition, but the role of this organism in the initiation and progression of dental caries has yet to be established. To identify proteins that are differentially expressed by S. oralis growing under conditions of low pH, soluble cellular proteins extracted from bacteria grown in batch culture at pH 5.2 or 7.0 were analyzed by two-dimensional (2-D) gel electrophoresis. Thirty-nine proteins had altered expression at low pH; these were excised, digested with trypsin using an in-gel protocol, and further analyzed by peptide mass fingerprinting using matrix-assisted laser desorption ionization mass spectrometry. The resulting fingerprints were compared with the genomic database for Streptococcus pneumoniae, an organism that is phylogenetically closely related to S. oralis, and putative functions for the majority of these proteins were determined on the basis of functional homology. Twenty-eight proteins were up-regulated following growth at pH 5.2; these included enzymes of the glycolytic pathway (glyceraldehyde-3-phosphate dehydrogenase and lactate dehydrogenase), the polypeptide chains comprising ATP synthase, and proteins that are considered to play a role in the general stress response of bacteria, including the 60-kDa chaperone, Hsp33, and superoxide dismutase, and three distinct ABC transporters. These data identify, for the first time, gene products that may be important in the survival and proliferation of nonmutans aciduric S. oralis under conditions of low pH that are likely to be encountered by this organism in vivo.


Subject(s)
Bacterial Proteins/metabolism , Gene Expression Regulation, Bacterial , Streptococcus oralis/growth & development , Bacterial Proteins/genetics , Child , Electrophoresis, Gel, Two-Dimensional , Humans , Hydrogen-Ion Concentration , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Streptococcus oralis/metabolism
5.
J Med Microbiol ; 50(7): 620-626, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11444772

ABSTRACT

Enterococci are becoming increasingly important nosocomial pathogens, a fact mainly attributed to their antimicrobial resistance profiles. However, the enzymic activities required for these organisms to proliferate in vivo have received little attention. Enterococcus faecalis has been shown previously to produce an endo-beta-N-acetylglucosaminidase activity which cleaves high mannose-type glycans in glycoproteins between the N-acetylglucosamine residues of the pentasaccharide core. This study investigated the distribution of this endoglycosidase activity amongst the other enterococcal species. Ribonuclease B, a high mannose-type glycoprotein, was used as a substrate and endoglycosidase activity was demonstrated by a combination of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry and high pH anion-exchange chromatography. Endo-beta-N-acetylglucosaminidase activity was present in 10 of the 18 enterococcal species isolated from both human and animal sources, including all E. faecalis strains. The most notable exception was the lack of this activity in all E. faecium isolates tested. All enterococcal species possessing endoglycosidase activity utilised the liberated glycans to support bacterial growth.


Subject(s)
Enterococcus/enzymology , Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase/metabolism , Glycosylation , Molecular Weight , Polysaccharides/metabolism , Ribonucleases/metabolism , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
6.
J Clin Microbiol ; 39(3): 995-1001, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11230417

ABSTRACT

The production of mannosidase activity by all currently recognized species of human viridans group streptococci was determined using an assay in which bacterial growth was dependent on the degradation of the high-mannose-type glycans of RNase B and subsequent utilization of released mannose. RNase B is an excellent substrate for the demonstration of mannosidase activity since it is a glycoprotein with a single glycosylation site which is occupied by high-mannose-type glycoforms containing five to nine mannose residues. Mannosidase activity was produced only by some members of the mitis group (Streptococcus mitis, Streptococcus oralis, Streptococcus gordonii, Streptococcus cristatus, Streptococcus infantis, Streptococcus parasanguinis, and Streptococcus pneumoniae) and Streptococcus intermedius of the anginosus group. None of the other species within the salivarius and mutans groups or Streptococcus peroris and Streptococcus sanguinis produced mannosidase activity. Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry, it was demonstrated that the Man(5) glycan alone was degraded while Man(6) to Man(9), which contain terminal alpha(1-->2) mannose residues in addition to the alpha(1-->3), alpha(1-->6), and beta(1-->4) residues present in Man(5), remained intact. Investigations on mannosidase production using synthetic (4-methylumbelliferone- or p-nitrophenol-linked) alpha- or beta-mannosides as substrates indicated that there was no correlation between degradation of these substrates and degradation of the Man(5) glycan of RNase B. No species degraded these alpha-linked mannosides, while degradation of the beta-linked synthetic substrates was restricted to strains within the Streptococcus anginosus, S. gordonii, and S. intermedius species. The data generated using a native glycoprotein as the substrate demonstrate that mannosidase production within the viridans group streptococci is more widely distributed than had previously been considered.


Subject(s)
Mannosidases/metabolism , Streptococcus/enzymology , Culture Media , Glycoside Hydrolases/metabolism , Humans , Ribonucleases/metabolism , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Streptococcus/growth & development
7.
Br J Pharmacol ; 131(4): 673-82, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11030715

ABSTRACT

In rat pulmonary artery pre-contracted with phenylephrine, the mechanisms of relaxation to the nitric oxide (NO) donor, spermine NONOate, were investigated. Responses to spermine NONOate were only partially blocked by the soluble guanylate cyclase inhibitor, ODQ (1H:-[1,2,4]Oxadiazolo-[4,3,-a]quinoxalin-1-one) at concentrations up to 30 microM. Ten microM ODQ gave maximal inhibition. Endothelium removal had no effect on the potency of spermine NONOate or its inhibition by ODQ. The protein kinase G inhibitor, Rp-8-Br-cGMPS (100 microM), caused minimal inhibition of spermine NONOate despite causing marked inhibition of glyceryl trinitrate and isosorbide dinitrate. Spermine NONOate (100 microM) caused a 35 fold increase in guanosine 3'5' cyclic monophosphate (cyclic GMP) above basal levels in pulmonary artery rings. ODQ (3 microM) abolished this cyclic GMP production but did not inhibit corresponding relaxant responses. Similar results were seen with another NONOate (MAHMA NONOate; 10 microM). ODQ-resistant relaxation to spermine NONOate (i. e. relaxation seen in the presence of 10 microM ODQ) was inhibited by potassium (80 mM), charybdotoxin (300 nM), iberiotoxin (300 nM), apamin (100 nM), ouabain (1 mM) or thapsigargin (100 nM) but not by 4-aminopyridine (3 mM), glybenclamide (10 microM) or diltiazem (10 microM). Potassium, charybdotoxin, ouabain and thapsigargin also inhibited ODQ-resistant relaxation to FK409 ((+/-)-E:-4-ethyl-2-[E:-hydroxyimino]-5-nitro-3-hexenamide). We conclude that, on rat pulmonary artery, spermine NONOate can produce cyclic GMP-independent relaxation that involves, at least in part, activation of Na(+)/K(+)-ATPase, sarco-endoplasmic reticulum Ca(2+)-ATPase and calcium-activated potassium channels.


Subject(s)
Cyclic GMP/physiology , Nitric Oxide Donors/pharmacology , Pulmonary Artery/drug effects , Spermine/analogs & derivatives , Vasodilation/drug effects , Animals , Cyclic GMP/analogs & derivatives , Cyclic GMP/pharmacology , Male , Nitrogen Oxides , Oxadiazoles/pharmacology , Pulmonary Artery/physiology , Quinoxalines/pharmacology , Rats , Rats, Wistar , Spermine/pharmacology
8.
Anal Biochem ; 282(2): 165-72, 2000 Jul 01.
Article in English | MEDLINE | ID: mdl-10873270

ABSTRACT

Ribonuclease (RNase) B incubated with purified enzymes, whole bacterial cultures, or their separated components-cells and supernates-have been directly analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-ToF) to detect exomannosidases and to evaluate their specificities and location. Enzymatic cleavage was monitored by observing changes in RNase B glycoform population. Thus a nonspecific alpha-(1 --> 2)-mannosidase activity converts the glycoprotein to its Man(5) form, identifiable by its mass of 14,899 [M + H](+); this species subsequently is converted, by the actions of alpha-(1 --> 3) and alpha-(1 --> 6)-mannosidases, to the Man(1) form via Man(4), Man(3), and Man(2). The Man(1) glycoform (which is readily isolated) has then similarly been used for identifying beta-(1 --> 4)-mannosidase and the derived Man(0) form has served in turn as a natural substrate for beta-(1 --> 4) N-acetylglucosaminidase producing a species possessing a single asparagine-linked GlcNAc residue (mass 13,886). Mannose liberated from the actions of mannosidases can, if desired, be quantified by, for example, chromatography. The actions and specificities of endoglycosidases such as a peptide-N-glycosidase F (PNGase F) and of endo-N-acetlyglucosaminidases (e.g., endo-F and endo-H), which respectively cleave between the GlcNAc&bond;Asn and GlcNAc&bond;GlcNAc bonds of N-linked glycoproteins, are also demonstrable by MALDI-ToF analysis of RNase B (and derived products). From these digests the completely deglycosylated polypeptide corresponding to RNase A in which Asn has been converted to Asp (mass 13,684) and a species corresponding to RNase A + GlcNAc (mass 13,886) are produced, together with their corresponding free oligosaccharides which are amenable to analysis by both MALDI-ToF and by HPLC.


Subject(s)
Amidohydrolases/analysis , Hexosaminidases/analysis , Mannosidases/analysis , Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Bacteria/enzymology , Culture Media , Mannose/analysis , Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase , Ribonucleases/chemistry
9.
J Med Microbiol ; 49(3): 235-244, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10707943

ABSTRACT

Streptococcus oralis, the most virulent of the viridans streptococci, produces a sialidase and this exo-glycosidase has been implicated in the disease process of a number of pathogens. The sialidase of S. oralis strain AR3 was purified in order to understand the characteristics of this putative virulence determinant. The enzyme isolated as a high mol. wt aggregate (c. 325 kDa) was purified 4520-fold from late exponential phase cultures by a combination of ultrafiltration, ammonium sulphate precipitation, ion-exchange and gel filtration chromatography. The sialidase component had a mol.wt of 144 kDa as determined by SDS-PAGE analysis. The purified sialidase released N-acetylneuraminic acid from a range of sialoglycoconjugates including human alpha1-acid glycoprotein, bovine submaxillary mucin, colominic acid and sialyl-alpha2,3- and sialyl-alpha2,6-lactose. Also, N-glycolylneuraminic acid was cleaved from bovine submaxillary mucin. The sialidase had a Km of 11.8 microM for alpha1-acid glycoprotein, was active over a broad pH range with a pH optimum of 6.0 and cleaved alpha2,3-, alpha2,6- and alpha2-8-sialyl glycosidic linkages with a marked preference for alpha2,3-linkages. The enzyme was competitively inhibited by the sialic acid derivative, 2,3-dehydro-N-acetylneuraminic acid, with a K(IC) of 1.2 microM. The characteristics of the purified sialidase would support a nutritional role for this enzyme that may be significant in the proliferation of this organism in the oral cavity and at extra-oral sites in association with life-threatening infections.


Subject(s)
Neuraminidase/isolation & purification , Streptococcus oralis/enzymology , Chromatography, Gel , Chromatography, Ion Exchange , Electrophoresis, Polyacrylamide Gel , Humans , Kinetics , Molecular Weight , Neuraminidase/antagonists & inhibitors , Neuraminidase/chemistry , Neuraminidase/metabolism , Sialoglycoproteins/metabolism , Streptococcus oralis/pathogenicity , Substrate Specificity , Ultrafiltration , Virulence
10.
J Bacteriol ; 182(4): 882-90, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10648510

ABSTRACT

Enterococcus faecalis is associated with a high proportion of nosocomial infections; however, little is known of the ability of this organism to proliferate in vivo. The ability of RNase B, a model glycoprotein with a single N-glycosylation site occupied by a family of high-mannose-type glycans (Man(5)- to Man(9)-GlcNAc(2)), to support growth of E. faecalis was investigated. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of RNase B demonstrated a reduction in the molecular mass of this glycoprotein during bacterial growth. Further analysis by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry revealed that this mass shift was due to the degradation of all high-mannose-type glycoforms to a single N-linked N-acetylglucosamine residue. High-pH anion-exchange chromatography analysis during exponential growth demonstrated the presence of RNase B-derived glycans in the culture supernatant, indicating the presence of an endoglycosidase activity. The free glycans were eluted with the same retention times as those generated by the action of Streptomyces plicatus endo-beta-N-acetylglucosaminidase H on RNase B. The cleavage specificity was confirmed by MALDI-TOF analysis of the free glycans, which showed glycan species containing only one N-acetylglucosamine residue. No free glycans were detectable after 5 h of bacterial growth, and we have subsequently demonstrated the presence of mannosidase activity in E. faecalis, which releases free mannose from RNase B-derived glycans. We propose that this deglycosylation of glycoproteins containing high-mannose-type glycans and the subsequent degradation of the released glycans by E. faecalis may play a role in the survival and persistence of this nosocomial pathogen in vivo.


Subject(s)
Enterococcus faecalis/enzymology , Enterococcus faecalis/growth & development , Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase/metabolism , Ribonucleases/metabolism , Carbohydrate Sequence , Electrophoresis, Polyacrylamide Gel , Enzyme Induction , Gram-Positive Bacterial Infections/microbiology , Humans , Mannose/metabolism , Mannosidases/metabolism , Mass Spectrometry/methods , Molecular Sequence Data , Polysaccharides/analysis , Ribonucleases/chemistry
11.
J Med Microbiol ; 48(4): 375-381, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10509480

ABSTRACT

Streptococcus oralis has emerged as one of the most important organisms of the viridans streptococcus group in terms of infections and is recognised as an agent of infective endocarditis and, in immunocompromised patients, septicaemia. The mechanisms by which this organism proliferates in vivo are unknown. However, host-derived sialic acids -- including N-acetylneuraminic acid (NeuNAc) which is present in serum and cell-associated glycoproteins -- are a potential source of fermentable carbohydrate for bacterial proliferation, especially for sialidase-producing bacteria, including S. oralis. To further elucidate the role of NeuNAc in supporting growth, this study determined the ability of S. oralis strain AR3 (isolated from a patient with infective endocarditis) to transport NeuNAc and characterised the transport system. The transport of [14C]-labelled NeuNAc into S. oralis was monitored and this transport system was induced by growth of the bacteria in the presence of the N-acetylated sugars NeuNAc, N-acetylglucosamine and N-acetylmannosamine. The transport system followed typical Michaelis-Menten kinetics, with a Km of 21.0 microM and a Vmax of 2.65 nmoles of NeuNAc transported/min/mg of dry cell mass. NeuNAc transport was inhibited by the presence of exogenous N-glycolylneuraminic acid, a related sialic acid. Chlorhexidine, NaF and 2,4-dinitrophenol were potent inhibitors of the transport system, suggesting that the uptake of NeuNAc occurs via a proton motive force-dependent permease system. This is the first report of the mechanism by which NeuNAc transport occurs in pathogenic streptococci. This transport process may have relevance to the acquisition of a source of fermentable carbohydrate and thus bacterial proliferation in vivo.


Subject(s)
Endocarditis, Bacterial/microbiology , N-Acetylneuraminic Acid/metabolism , Streptococcal Infections/microbiology , Streptococcus oralis/metabolism , 2,4-Dinitrophenol/pharmacology , Acetylglucosamine/metabolism , Anti-Bacterial Agents/pharmacology , Arsenates/pharmacology , Biological Transport , Chlorhexidine/pharmacology , Hexosamines/metabolism , Humans , Kinetics , Monosaccharides/metabolism , Proton-Motive Force/drug effects , Reproducibility of Results , Sodium Azide/pharmacology , Sodium Fluoride/pharmacology , Streptococcus oralis/drug effects , Streptococcus oralis/growth & development , Uncoupling Agents/pharmacology
12.
J Dent Res ; 78(7): 1370-80, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10403465

ABSTRACT

Viridans streptococci have emerged as major opportunistic pathogens. We suggest that for these bacteria to proliferate in vivo and cause disease, they must utilize host tissue components. We have therefore examined the ability of all recognized species of viridans streptococci to liberate and utilize the constituent sugars of the glycans of the extensively sialylated human serum alpha1-acid glycoprotein (AGP) as the sole source of carbohydrate to support in vitro growth. Analysis of residual glycans following bacterial growth was performed by high-pH anion exchange chromatography with pulsed amperometric detection and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Only those species which produced sialidase-namely, Streptococcus oralis, S. intermedius, and S. defectivus--grew on AGP. The extent of degradation of glycans was dependent on the particular glycosidases produced by the bacteria. S. defectivus produced only a sialidase which released the terminal N-acetylneuraminic acid residues of the glycans, and the liberated sugar was utilized. S. intermedius also produced beta-galactosidase and beta-N-acetylglucosaminidase, which removed galactose and N-acetylglucosamine from desialylated glycans, all of which again were utilized by the organism. S. oralis produced beta-galactosidase, beta-N-acetylglucosaminidase, and alpha-fucosidase and novel alpha- and beta-mannosidases which were apparent only from the analysis of the residual sugars of AGP. S. oralis cleaved all the sugars from AGP except for 22% of the N-acetylglucosamine. The residual N-acetylglucosamine residues remaining were those linked to the asparagine of the peptide backbone. All the monosaccharides released by S. oralis from AGP, with the exception of fucose, were utilized. Sialidase production may be a key factor for growth of these species of viridans streptococci on glycoproteins in vivo, since they are commonly associated with extra-oral diseases, with S. oralis emerging as an important pathogen.


Subject(s)
Orosomucoid/metabolism , Streptococcus/growth & development , Acetylglucosaminidase/metabolism , Anions , Chromatography, Ion Exchange , Glycoside Hydrolases/metabolism , Humans , Hydrogen-Ion Concentration , Mannosidases/metabolism , Mass Spectrometry , Monosaccharides/metabolism , N-Acetylneuraminic Acid/metabolism , Neuraminidase/metabolism , Opportunistic Infections , Polysaccharides/metabolism , Streptococcal Infections , Streptococcus/enzymology , Streptococcus/metabolism , Streptococcus oralis/enzymology , Streptococcus oralis/growth & development , Streptococcus oralis/metabolism , alpha-L-Fucosidase/metabolism , beta-Galactosidase/metabolism
13.
J Pharm Pharmacol ; 51(2): 135-9, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10217311

ABSTRACT

ODQ, (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, an inhibitor of soluble guanylate cyclase) inhibits vasorelaxant responses to nitric oxide (NO)-donor drugs, but the extent of the inhibition varies depending on the NO donor studied. The purpose of this study was to test the hypothesis that these variations in the effects of ODQ reflect differences in the mechanisms whereby each NO donor generates NO. On pulmonary artery preparations pre-contracted submaximally with phenylephrine, ODQ (3 microM) almost abolished the relaxant responses to glyceryl trinitrate, isosorbide dinitrate and nitroprusside; each of these drugs requires activation in the tissue (by enzymes or reducing agents) to generate NO. In contrast, ODQ (3 microM) caused a parallel shift in the concentration-relaxation curves to linsidomine (SIN-1), FK409, MAHMA NONOate and spermine NONOate (1.63 to 2.54 log units) with no depression in maximum response; each of these NO donors generates NO in the physiological bathing solution without requiring tissue activation. For the four drugs in this group, the effects of 10 microM ODQ were not significantly greater than the effects of 3 microM ODQ; thus there was an ODQ-resistant component to the response suggesting that part of the response involved a mechanism that was independent of soluble guanylate cyclase. NO donors that require tissue activation probably generate NO within the smooth-muscle cell, whereas those that do not require tissue activation generate NO outside the cell. Hence it is concluded that the site of NO generation (intra- or extracellular) might determine whether or not there is an ODQ-resistant component in the relaxation response.


Subject(s)
Enzyme Inhibitors/pharmacology , Nitric Oxide Donors/pharmacology , Oxadiazoles/pharmacology , Pulmonary Artery/drug effects , Quinoxalines/pharmacology , Animals , Dose-Response Relationship, Drug , Guanylate Cyclase/antagonists & inhibitors , Hydrazines/pharmacology , In Vitro Techniques , Male , Molsidomine/analogs & derivatives , Molsidomine/pharmacology , Nitric Oxide/biosynthesis , Nitro Compounds/pharmacology , Nitrogen Oxides , Pulmonary Artery/physiology , Rats , Rats, Wistar , Spermine/analogs & derivatives , Spermine/pharmacology , Vasodilation/drug effects
14.
Glycobiology ; 9(5): 469-79, 1999 May.
Article in English | MEDLINE | ID: mdl-10207179

ABSTRACT

Streptococcus oralis is the agent of a large number of infections in immunocompromised patients, but little is known regarding the mechanisms by which this fermentative organism proliferates in vivo. Glycoproteins are widespread within the circulation and host tissues, and could provide a source of fermentable carbohydrate for the growth of those pathogenic organisms with the capacity to release monosaccharides from glycans via the production of specific glycosidases. The ability of acute phase serum alpha1-acid glycoprotein to support growth of S.oralis in vitro has been examined as a model for growth of this organism on N-linked glycoproteins. Growth was accompanied by the production of a range of glycosidases (sialidase, N-acetyl-beta-D-glucosaminidase, and beta-D-galactosidase) as measured using the 4-methylumbelliferone-linked substrates. The residual glycoprotein glycans remaining during growth of this organism were released by treatment with hydrazine and their analysis by HPAEC-PAD and MALDI demonstrated extensive degradation of all glycan chains with only terminal N-acetylglucosamine residues attached to asparagines of the protein backbone remaining when growth was complete. Monosaccharides were released sequentially from the glycans by S.oralis glycosidases in the order sialic acid, galactose, fucose, nonterminal N-acetylglucosamine, and mannose due to the actions of exo-glycosidic activities, including mannosidases which have not previously been reported for S.oralis. All released monosaccharides were metabolized during growth with the exception of fucose which remained free in culture supernatants. Direct release of oligosaccharides was not observed, indicating the absence of endo-glycosidases in S.oralis. We propose that this mechanism of deglycosylation of host glycoproteins and the subsequent utilization of released monosaccharides is important in the survival and persistence of this and other pathogenic bacteria in vivo.


Subject(s)
Orosomucoid/metabolism , Polysaccharides/metabolism , Streptococcus oralis/growth & development , Streptococcus oralis/metabolism , Carbohydrate Sequence , Chromatography, Ion Exchange , Enzyme Inhibitors/pharmacology , Glycoside Hydrolases/biosynthesis , Glycosylation , Humans , In Vitro Techniques , Molecular Sequence Data , Monosaccharides/analysis , N-Acetylneuraminic Acid/analogs & derivatives , N-Acetylneuraminic Acid/pharmacology , Neuraminidase/antagonists & inhibitors , Orosomucoid/chemistry , Polysaccharides/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Streptococcus oralis/drug effects
15.
Carbohydr Res ; 312(3): 159-64, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9836455

ABSTRACT

Streptococcus oralis when cultured using ribonuclease B as the sole source of carbohydrate, selectively uses the sugars of the Man5 glycoform as shown by HPAEC and MALDI-TOF mass spectrometric analyses. The organism is able to do this by producing novel alpha-(1-->3), alpha-(1-->6) and beta-(1-->4) mannosidase activities and these act in a concerted manner in what appears as a single-step process. The selective utilisation of Man5 is explained by the absence of an alpha-(1-->2) mannosidase which is required to initiate breakdown of the glycan chains present in the other glycoforms which are components of the glycoprotein.


Subject(s)
Mannosidases/metabolism , Ribonucleases/metabolism , Streptococcus oralis/enzymology , Carbohydrate Conformation , Carbohydrate Sequence , Cell Division/physiology , Chromatography, High Pressure Liquid , Glycoproteins/metabolism , Mannans/chemistry , Molecular Sequence Data , Oligosaccharides/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Substrate Specificity
16.
Eur J Pharmacol ; 356(1): 49-57, 1998 Aug 28.
Article in English | MEDLINE | ID: mdl-9761423

ABSTRACT

The pulmonary vasorelaxant properties of two NONOates (diazeniumdiolates) were examined because this novel group of nitric oxide (NO) donors may be useful in pulmonary hypertension. MAHMA NONOate ((Z)-1-¿N-Methyl-N-[6-(N-methylammoniohexyl)amino]¿ diazen-1-ium-1,2-diolate) and spermine NONOate ((Z)- 1-¿N-[3-aminopropyl]-N-[4-(3-aminopropylammonio)butyl]-amino¿di azen-1-ium-1,2-diolate) decomposed at different rates (half-lives 1.3 min and 73 min, respectively; 37 degrees C, pH 7.3) but generated the same total amount of NO. They fully relaxed submaximally contracted ring preparations of main and intralobar pulmonary arteries from rats. Responses were inhibited by the guanylate cyclase inhibitor, ODQ (1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one). Potency was not affected by choice of contractile spasmogen (phenylephrine, endothelin-1, thromboxane-mimetic) or endothelium removal, and tolerance did not develop; thus the drugs had properties important for use in pulmonary hypertension. MAHMA NONOate was 10-40-fold more potent than spermine NONOate but responses to spermine NONOate were more sustained (spermine NONOate > 60 min; MAHMA NONOate < 7 min). It is concluded that the differences in potency and time-course reflect the different rates of NO generation by these NONOates.


Subject(s)
Hydrazines/pharmacology , Mutagens/pharmacology , Pulmonary Artery/drug effects , Spermine/analogs & derivatives , Animals , Dose-Response Relationship, Drug , Drug Tolerance , Enzyme Inhibitors/pharmacology , Guanylate Cyclase/antagonists & inhibitors , Hydrazines/chemistry , Hydrazines/metabolism , In Vitro Techniques , Male , Mutagens/chemistry , Mutagens/metabolism , Nitric Oxide/metabolism , Nitrogen Oxides , Nitroglycerin/pharmacology , Oxadiazoles/pharmacology , Pulmonary Artery/physiology , Quinoxalines/pharmacology , Rats , Rats, Wistar , Spermine/chemistry , Spermine/metabolism , Spermine/pharmacology , Vasodilation/drug effects , Vasodilator Agents/pharmacology
20.
Arch Oral Biol ; 42(12): 827-34, 1997 Dec.
Article in English | MEDLINE | ID: mdl-9460536

ABSTRACT

The ability of three Porphyromonas spp., seven Prevotella spp., seven Fusobacterium spp. and two related Bacteroides spp. (B. levii and B. macacae) to degrade an extensive range of synthetic endo-, amino- and diamino peptidase substrates linked to the fluorescent leaving group 7-amido-4-methylcoumarin (NHMec) was investigated. Many more species than was previously recognized exhibited peptidase activities, albeit at lower levels than those already described for Porphyromonas gingivalis. Detection of chymotrypsin-like activity was dependent on which of three NHMec-linked substrates was used, but all species exhibited degradative activity with at least one of these substrates. Elastase-like activity was detected in all species though not all species reacted with each of the elastase substrates. Glycylprolyl peptidase activity was detected in all of the species tested with the exception of F. mortiferum, F. gonidiaformans, F. naviforme and F. necrophorum. While the detection of peptidase activities does not appear to be useful for the differentiation of species within the genera Bacteroides and Prevotella, its ability to differentiate species of the genus Porphyromonas or Fusobacterium warrants further investigation.


Subject(s)
Endopeptidases/metabolism , Fusobacterium/enzymology , Porphyromonas/enzymology , Prevotella/enzymology , Alanine/metabolism , Aminopeptidases/metabolism , Bacteroides/classification , Bacteroides/enzymology , Chymotrypsin/metabolism , Coumarins , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/metabolism , Fluorescent Dyes , Fusobacterium/classification , Fusobacterium necrophorum/metabolism , Humans , Indicators and Reagents , Lysine/metabolism , Mouth/microbiology , Oligopeptides , Pancreatic Elastase/metabolism , Phenylalanine/metabolism , Porphyromonas/classification , Porphyromonas gingivalis/enzymology , Prevotella/classification , Proline/metabolism , Tyrosine/metabolism , Virulence
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