Isolation and Some Properties of Fimbriae of Oral <Emphasis Type="Italic">Streptococcus intermedius</Emphasis>

Streptococcus intermedius 1208-1 carried linear fiber-like fimbriae that extended radially from the cell surface. The fimbriae were isolated by pipetting and sonication and were purified by ammonium sulfate precipitation followed by a column chromatography series. Heat treatment in the presence of sodium dodecyl sulfate resulted in the dissociation into smaller molecules. Rabbit antiserum raised against the purified protein reacted with fimbriae on the surface of bacteria under immunogold staining. Serotype g or g-related strains produced the fimbriae and aggregated in human saliva. The aggregation was inhibited by the anti-fimbriae immunoglobulin Fab fragment or the purified fimbriae.     

Isolation and composition of the constitutive agglutinins from haploid Saccharomyces cerevisiae cells

Sex-specific agglutinins from the cell surface of haploid cells of Saccharomyces cerevisiae (X2180, mt^a and mt) were purified and analysed. The constitutive agglutinin from mt^a cells was extractable with 3 mM dithiothreitol. It was shown to be a glycoprotein (3% mannose) with an apparent Mr of 43,000 based on gel filtration, but in SDS-PAGE it behaved as a much smaller molecule (Mr between 18,000 and 26,000). About one in three amino acids was a hydroxyamino acid. Its biological activity was resistant to boiling for 1 h, but sensitive to pronase. Intact mt cells retained their agglutinability in the presence of dithiothreitol but limited trypsinizing released a biologically active agglutinin fragment. It had an apparent Mr of 320,000 (gel filtration). When analysed by SDS-PAGE, a single diffuse band with an apparent Mr of 225,000 was observed. The protein was 94% (w/w) mannose with a trace of N-acetyl glucosamine. Its biological activity was almost completely lost after boiling for 1 h. Both agglutinins behaved as monovalent molecules and specifically inhibited the biological activity of both noninduced and pheromone-induced cells. Pheromone treatment of mt^a cells resulted in an apparent 32-fold increase in agglutinin activity at the cell surface, whereas pheromone treatment of mt cells only doubled the apparent agglutinin activity.Abbreviations mt mating type - DTT dithiothreitol - SDS-PAGE sodium dodecyl sulphate polyacrylamide gel electrophoresis - YPG yeast-peptone-glucose - PAS periodic-acid-Schiff reagent     

Identification of a fibrinolytic enzyme by <Emphasis Type="Italic">Bacillus vallismortis</Emphasis> and its potential as a bacteriolytic enzyme against <Emphasis Type="Italic">Streptococcus mutans</Emphasis>

A potent fibrinolytic enzyme-producing bacterium was isolated from the traditional Korean condiment Chungkook-jang and identified as Bacillus vallismortis Ace02. The extracellular fibrinolytic enzyme was purified with a 18% recovery of activity from supernatant cultures using CM-Sepharose column chromatography and Sephacryl S-200 gel filtration. The specific activity of the purified enzyme was 757 kFU mg⁻¹. Its molecular mass was about 28 kDa and the initial amino acids of the N-terminal sequence were AQSVPYGVSQ. The full amino acid sequence of fibrinolytic enzyme Ace02 corresponded with bacteriolytic enzyme, L27, from Bacillus licheniformis, which has strong lytic activity against Streptococcus mutans, a major causative strain of dental caries. This suggests that the purified enzyme should be used for prevention of dental caries as well as being an effective thrombolytic agent.     

Purification and characterization of sialidase fromClostridium sordellii G12

Sialidase secreted by the urease-positiveClostridium sordellii strain G12 was isolated from culture medium and purified to apparent homogeneity as estimated by Fast Protein Liquid Chromatography (FPLC) and sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE). For this purpose, ion-exchange chromatography, gel filtration, isoelectric focusing, and FPLC on ion-exchange resin and gel filtration materials were used. The sialidase was purified 159 300-fold from 5 l of culture medium, yielding 9 g of enzyme protein with a specific activity of 480 U/mg. For the denatured (SDS-PAGE) and native (FPLC) sialidase relative molecular masses of 40 000 and 38 500 Da, respectively, were estimated. The substrate specificity, kinetic data, and pH-optimum of the enzyme are similar to those of other bacterial sialidases. The influences of salt or serum proteins on enzyme activity are of interest.Abbreviations MU-Neu5Ac 4-methylumbelliferyl -d-N-acetylneuraminic acid - Ganglioside GD1a IV³NeuAc, ll³NeuAc-GgOse₄Cer - Neu5Ac2en 2-deoxy-2,3-didehydro-N-acetylneuraminic acid     

Purification and characterization of a lactonase from<Emphasis Type="Italic"> Erwinia cypripedii</Emphasis> 314B that hydrolyzes (<Emphasis Type="Italic">S</Emphasis>)-5-oxo-2-tetrahydrofurancarboxylic acid

A bacterium, strain 314B, able to assimilate (S)-5-oxo-2-tetrahydrofurancarboxylic acid was isolated from soil and identified as Erwinia cypripedii. A lactonase hydrolyzing (S)-5-oxo-2-tetrahydrofurancarboxylic acid to l--hydroxyglutaric acid was purified 63-fold with 2% recovery from crude extracts of this bacterium to homogeneity as judged by SDS-PAGE. The molecular masses estimated by SDS-PAGE and gel filtration were 41 kDa and 79 kDa, respectively. The maximum activity was observed at pH 6.5–7.5 and 35–45 °C. The enzyme showed lower activity toward dl-2-oxotetrahydrofuran-4,5-dicarboxylic acid, but did not act on (R)-5-oxo-2-tetrahydrofurancarboxylic acid and other natural and synthetic lactones tested.     

Interaction of the salivary low-molecular-weight mucin (MG2) with Actinobacillus actinomycetemcomitans

Periodontitis is associated with the presence of certain Gram-negative bacteria in the oral cavity, among these Actinobacillus actinomycetemcomitans. In order to determine which types of salivary components interact with A. actinomycetemcomitans two strains (HG 1175 and FDC Y4) were incubated with whole saliva and individual glandular secretions, viz. parotid, submandibular, and sublingual saliva. Immunochemical analysis by immunoblotting of bacteria-bound salivary proteins showed that IgA, the low-molecular mucin MG2, parotid agglutinin, and a 300 kDa sublingual and submandibular glycoprotein, were bound to the bacterial strains tested. In addition, adherence of A. actinomycetemcomitans to salivary proteins in a solid-phase was studied. After electrophoresis and transfer of salivary proteins to nitrocellulose membranes A. actinomycetemcomitans adhered only to MG2. In this assay periodate treatment, mild acid hydrolysis or neuraminidase digestion of the saliva glycoproteins abolished binding of two clinical isolates (HG 1175 and NY 664), suggesting that sialic acid residues on MG2 are involved in the binding. In contrast, adherence of the smooth laboratory strain Y4 was not affected by removal of sialic acid residues or even periodate treatment of MG2.Abbreviations S-IgA Secretory IgA - MG1 high-molecular-weight mucin - MG2 low-molecular-weight mucin - EP-GP extra parotid-glycoprotein - PRPs proline-rich proteins - SNA Sambucus nigra agglutinin - MAA Maackia amurensis agglutinin - PNA peanut agglutinin - UEA Ulex europaeus agglutinin     

Purification and biochemical characterization of a thermostable extracellular glucoamylase produced by the thermotolerant fungus <Emphasis Type="Italic">Paecilomyces variotii</Emphasis>

An extracellular glucoamylase produced by Paecilomyces variotii was purified using DEAE-cellulose ion exchange chromatography and Sephadex G-100 gel filtration. The purified protein migrated as a single band in 7% PAGE and 8% SDS-PAGE. The estimated molecular mass was 86.5 kDa (SDS-PAGE). Optima of temperature and pH were 55 °C and 5.0, respectively. In the absence of substrate the purified glucoamylase was stable for 1 h at 50 and 55 °C, with a t ₅₀ of 45 min at 60 °C. The substrate contributed to protect the enzyme against thermal denaturation. The enzyme was mainly activated by manganese metal ions. The glucoamylase produced by P. variotii preferentially hydrolyzed amylopectin, glycogen and starch, and to a lesser extent malto-oligossacarides and amylose. Sucrose, p-nitrophenyl α-d-maltoside, methyl-α-d-glucopyranoside, pullulan, α- and β-cyclodextrin, and trehalose were not hydrolyzed. After 24 h, the products of starch hydrolysis, analyzed by thin layer chromatography, showed only glucose. The circular dichroism spectrum showed a protein rich in α-helix. The sequence of amino acids of the purified enzyme VVTDSFR appears similar to glucoamylases purified from Talaromyces emersonii and with the precursor of the glucoamylase from Aspergillus oryzae. These results suggested the character of the enzyme studied as a glucoamylase (1,4-α-d-glucan glucohydrolase).     

Sexual agglutinin of mating-type minus gametes inChlamydomonas reinhardtii

The sexual agglutinin from the mating-type minus gametes ofChlamydomonas reinhardtii was purified by gel filtration and hydroxyapatite chromotography. The minus agglutinin was identified as a single glycopolypeptide termed Agg(-) of very high molecular weight by SDS-poly-acrylamide gel electrophoresis. It was also observed as a glycoprotein with agglutinin activity on non-SDS polyacrylamide gels. The native agglutinin appeared to be composed of a complex of Agg(-) subunits. It consisted of about 60% protein and 40% carbohydrate and the activity was diminished by a mild periodate oxidation. When the plus agglutinin was also purified and compared with the minus agglutinin, it was found that both agglutinins migrate in the same position by SDS-polyacrylamide gel electrophoresis, whereas their behaviors on gel filtration and hydroxyapatite chromatography are different.Abbreviations mt ^+/– mating-tape plus or minus - SDS sodium dodecyl sulfate - V_e elution volume - V_o void volume - kDa kilodalton     

Saliva of laboratory-reared Lutzomyia longipalpis exacerbates Leishmania (Leishmania) amazonensis infection more potently than saliva of wild-caught Lutzomyia longipalpis

In order to compare the saliva effect from wild-caught and lab-reared L. longipalpis on the development of experimental cutaneous leishmaniasis, C57BL/6 mice were inoculated subcutaneously into the hind footpads with promastigotes of L. (L.) amazonensis plus salivary gland lysate from wild-caught (SGL-W) and lab-colonized (SGL-C) vectors. Lesion sizes were significantly larger in the mice infected with both saliva compared to mice infected with parasites alone; moreover, the lesions caused by parasite + SGL-C were significantly larger than the lesions caused by parasite + SGL-W. Histopathological morphometric studies regarding the acute phase of infections showed lower numbers of polymorphonuclear cells, greater numbers of mononuclear cells and parasites in SGL-C infected mice compared to SGL-W infected mice. In the chronic phase of infection, the number of mononuclear cells was lower and the number of parasites was greater in SGL-C infected mice than SGL-W infected mice. In vitro studies showed increased infection index of macrophages infected with parasites plus saliva compared to infection with parasites alone, with no difference between the saliva infection indices. SDS-PAGE gel for SGL-C and SGL-W showed differences in the composition and quantity of protein bands, determined by densitometry. These results call attention to the experimental saliva model, which shows exacerbation of infection caused by sandfly saliva.     

Purification and characterization of homodimeric methylmalonyl-CoA mutase from<Emphasis Type="Italic"> Sinorhizobium meliloti</Emphasis>

High activity (>60 munit/mg protein) of 5-deoxyadenosylcobalamin-dependent methylmalonyl-CoA mutase (EC 5.4.99.2) was constantly found during growth of a strain of the root-nodule-forming bacterium Sinorhizobium meliloti harboring an extra plasmid-encoded copy of the methylmalonyl-CoA-mutase-encoding bhbA gene. The enzyme was purified to homogeneity and characterized. The purified enzyme was found to be a colorless apo-form. The apparent molecular weight of the enzyme was calculated to be 165,000±5,000 by Superdex 200 HR gel filtration. SDS-PAGE of the purified enzyme resolved one protein band with an apparent molecular mass of 80.0±2.0 kDa, indicating that the S. meliloti enzyme is composed of two identical subunits. The NH₂-terminal sequence was identical to that predicted from the bhbA nucleotide sequence. Monovalent cations were required for enzyme activity.Abbreviations AdoCbl 5-Deoxyadenosylcobalamin - KPB Potassium phosphate buffer - MCM Methylmalonyl-CoA mutase - PVDF Polyvinylidene difluoride     

Purification and partial characterization of serine protease from thermostable alkalophilic <Emphasis Type="Italic">Bacillus laterosporus</Emphasis>-AK1

An extracellular thermostable alkaline protease isolated from Bacillus laterosporus-AK1 was purified by sephadex G-200 gel filtration and DEAE cellulose ion-exchange chromatography techniques. The purified protease showed a maximum relative activity of 100% on casein substrate and appeared as a single band on SDS-PAGE with the molecular mass of 86.29 kDa. The protease was purified to 11.1-folds with a yield of 34.3%. Gelatin zymogram also revealed a clear hydrolytic zone due to proteolytic activity, which corresponded to the band obtained with SDS-PAGE. The protease enzyme had on optimum pH of 9.0 and exhibited highest activity at 75°C. The enzyme activity was highly susceptible to the specific serine protease inhibitor PMSF, suggesting the presence of serine residues at the active sites. Enzyme activity strongly enhanced by the metal ions Ca²⁺ and Mg²⁺ and this enzyme compatible with aril detergent stability retained 75% even 1-h incubation. The purified protease remove bloodstain completely when used with Wheel detergent.     

The expression of <Emphasis Type="Italic">Bacillus intermedius</Emphasis> glutamyl endopeptidase gene in <Emphasis Type="Italic">Bacillus subtilis</Emphasis> recombinant strains

The gene encoding for B. intermedius glutamyl endopeptidase (gseBi) has previously been cloned and its nucleotide sequence analyzed. In this study, the expression of this gene was explored in protease-deficient strain B. subtilis AJ73 during stationary phase of bacterial growth. We found that catabolite repression usually involved in control of endopeptidase expression during vegetative growth was not efficient at the late stationary phase. Testing of B. intermedius glutamyl endopeptidase gene expression with B. subtilis spo0-mutants revealed slight effect of these mutations on endopeptidase expression. Activity of glutamyl endopeptidase was partly left in B. subtilis ger-mutants. Probably, gseBi expression was not connected with sporulation. This enzyme might be involved in outgrowth of the spore, when germinating endospore converts into the vegetative cell. These data suggest complex regulation of B. intermedius glutamyl endopeptidase gene expression with contribution of several regulatory systems and demonstrate changes in control of enzyme biosynthesis at different stages of growth.     

Isolation of <Emphasis Type="BoldItalic">Serratia marcescens</Emphasis> as a chondroitinase-producing bacterium and purification of a novel chondroitinase AC

A strain of Serratia marcescens that produced chondroitinase was isolated from soil. It produced a novel chondroitinase AC, which was purified to homogeneity. The enzyme was composed of two identical subunits of 35 kDa as revealed by SDS-PAGE and gel filtration. The isoelectric point for the chondroitinase AC was 7.19. Its optimal activity was at pH 7.5 and 40 °C. The purified enzyme was active on chondroitin sulfates A and C and hyaluronic acid, but was not with chondroitin sulfate B (dermatan sulfate), heparin or heparan sulfate. The apparent K_m and V_max of the chondroitinase AC for chondroitin sulfate A were 0.4 mg ml^–1 and 85 mmol min^–1 mg^–1, respectively, and for chondroitin sulfate C, 0.5 mg ml^–1 and 103 mmol min^–1 mg^–1, respectively.     

Purification and some properties of endopolygalacturonase from Rhizopus sp. LKN

An endopolygalacturonase of Rhizopus sp. strain LKN, one of several isolates from tempe starter (ragi), was purified 235-fold by CM-Sephadex C-50, DEAE-Sephadex A-50 ion exchange chromatographies and Sephadex G-75 gel filtration. The purified enzyme was homogeneous by SDS-PAGE with a M _r of 38.5 kDa. Its K _m value for pectic acid was 2 mg/ml. It was stable at pH 4.5 to 11 and up to 50°C, with optimum activity at pH 4.5 to 4.75 and 55 to 60°C. Some ionic compounds enhanced the enzyme activity, whereas tannic acid at 0.5 mm caused about 90% inhibition.The authors are with the Department of Food Science and Technology, Faculty of Agriculture, Kyushu University, Hakozaki, Fukuoka 812, Japan.     

Adherence ofStreptococcus gordonii HG 222 in the presence of saliva

The influence of the presence of saliva from different salivary glands on the adherence ofStreptococcus gordonii strain HG 222 to saliva-coated polystyrene surfaces was tested. In the presence of undiluted parotid saliva or diluted whole, submandibular and sublingual saliva the adherence of HG 222 was enhanced by the formation of small aggregates on the attachment surface. In the presence of undiluted whole, submandibular and sublingual saliva large aggregates were formed and the adherence to saliva-coated polystyrene surfaces was inhibited.Adherence in the presence of whole saliva compared to adherence in buffer was decreased when lower densities of bacterial suspension were used, although in this case in the presence of whole saliva smaller bacterial aggregates were formed.In conclusion, these results suggest that the presence of saliva in solution may both enhance and decrease the adherence ofS. gordonii HG 222 to saliva-coated polystyrene surfaces, partly depending on the size of bacterial aggregates that are formed in the presence of saliva.Abbreviations CHW saliva clarified human whole saliva - PAR saliva parotid saliva - SM saliva submandibular saliva - SL saliva sublingual saliva     

Thiosulfate and tetrathionate degradation as well as biofilm generation by Thiobacillus intermedius and Thiobacillus versutus studied by microcalorimetry,HPLC, and ion-pair chromatography

The growth of Thiobacillus (T.) intermedius strain K12 and Thiobacillus versutus strain DSM 582 on thiosulfate and tetrathionate was studied combining on-line measurements of metabolic activity and sulfur compound analysis. Most results indicate that T. intermedius oxidized thiosulfate via tetrathionate to sulfate. Concomittantly, sulfur compound intermediates like triand pentathionate were detectable. The formation is probably the result of highly reactive sulfane monosulfonic acids. The formation of tetrathionate allows the cells to buffer temporarily the proton excretion from sulfuric acid production. With T. versutus intermediate sulfur compounds were not detectable, however, sulfur was detectable. The possibility of a thiosulfate oxidation via dithionate, S₂O _inf6 ^sup2- , is discussed. The on-line measurement of metabolic activity by microcalorimetry enabled us to detect that cells of T. intermedius adhere to surfaces and produce a biofilm by a metabolic process whereas those of T. versutus fail to do so. The importance of the finding is discussed.     

Binding and penetration ofRhizobium japonicum to cultured soybean cells

A cultured soybean cell line, SB-1 was used to evaluate the initial interaction between the soybean cells andRhizobium japonicum. Co-culturing ofR. japonicum with SB-1 cells in suspension resulted in strain-specific polar attachment. This attachment can be inhibited by galactose and antibodies raised against seed soybean agglutinin (SBA). A lectin was purified from SB-1 cells which shares properties with SBA in terms of immunological reactivity, sugar binding activity, polypeptide molecular weight and peptide maps. When the SB-1 cells were co-cultured withR. japonicum for three weeks in solid agar medium, histological staining revealed bacterial penetration into certain SB-1 cells. Furthermore, there were focal regions of cells with prominent nuclei representing actively proliferating regions. These observations are analogous to that ofin vivo nodule initiation in soybean roots.     

A thrombin inhibitor from the gut of <Emphasis Type="Italic">Boophilus microplus</Emphasis> ticks

A thrombin inhibitor was identified for the first time in the gut of the cattle tick Boophilus microplus. Here we present the partial purification and characterization of this new molecule, which was purified from the gut extract by three chromatographic steps: ion-exchange, gel filtration and affinity chromatography in a thrombin–Sepharose resin. In SDS-PAGE the inhibitor showed an apparent molecular mass of circa 26 kDa, which is different from the two thrombin inhibitors present in the saliva of this tick. The new inhibitor delays bovine plasma clotting time and inhibits both thrombin induced fibrinogen clotting and thrombin induced platelet aggregation. However, it does not interfere with thrombin amidolytic activity upon a small substrate (H-D-Phe-Pip-Arg-para-nitroanilide), which does not require binding to thrombin exosites. Therefore, the inhibitor does not block thrombin active site, although it must interfere with one of the thrombin exosites. B. microplus gut thrombin inhibitor (BmGTI) is also capable of enhancing activated protein C (APC) activity upon its specific substrate (H-D-Glu-Pro-Arg-para-nitroanilide), an activity never described before among B. microplus molecules.     

Human salivary aggregation in Streptococcus intermedius type g strains: relationship with IgA

Bacterial aggregation is an important step in elimination from the human body to protect against infection. Streptococcus intermedius K1K aggregates in human saliva. In this study, the salivary agglutinin was identified. The aggregation level was very strong in sonic-treated saliva and 1-microm filtrate. Preincubation of human saliva with anti-human alpha chain serum or anti-human whole saliva serum completely inhibited aggregation, but preincubation with anti-human micro chain serum or anti-Fc fragment of human IgG serum had no effect. Agglutinin of human saliva that could aggregate the strain K1K was purified using DEAE-Sepharose CL-6B, Phenyl-Sepharose CL-4B and Sephacryl S200HR gel filtration. Purified salivary agglutinin was characterized with electrophoresis and immunological techniques, indicating that purified material was IgA. Bacterial aggregation was dependent on the presence of calcium. Saliva filtrate specimens from eight healthy men and eight women showed different aggregation activities. Three men and one woman had little activity. These data show that the present bacterial aggregation was an immunoreaction between IgA in saliva and the bacteria dependent on the levels of calcium. In addition, the IgA in human saliva related with possible calcium-dependent antigen(s) on the surface of strain K1K.