Helcococcus kunzii is a gram-positive, catalase-negative opportunist. The organism has been isolated from the lower extremities and breast masses of several patients. A clinical isolate of Helcococcus kunzii was shown to possess a hemagglutinin-lectin with a specificity for N-acetylglucosamine and lactose, two structurally unrelated carbohydrates. The lectin is sensitive to protease, heat and mutanolysin. Electron microscopy failed to reveal fimbriae or fibrillae, suggesting that the lectin is associated with peptidoglycan or the cytoplasmic membrane. It is likely that the lectin is involved in adhesion and colonization of H. kunzii.

The research of bacterial adhesion and its significance is a large field covering different aspects of nature and human life, such as marine science, soil and plant ecology, food industry, and most importantly, the biomedical field.3,23,101 Adhesion of bacteria to human tissue surfaces and implanted biomaterial surfaces is an important step in the pathogenesis of infection.3,50

Oral bacteria, such as Streptococcus cricetus and S. sobrinus, are aggregated by high molecular weight fractions of the linear α-(1→6) dextran produced by Leuconostoc mesenteroides. The linkage specificity of this interaction with a cell surface lectin of the streptococci is high. As a further probe of factors affecting recognition, we prepared partially methylated samples of dextran of average MW of 2 × 106 and 104. 13C NMR spectroscopy proved to be a convenient method for determining both site and degree of monomethylation and dimethylation of the polymer: relative reactivity of the OH groups was established as 02: 04: 03 = 4.3: 1.7: 1.0. A methylation DS of only 0.17 caused almost complete loss of recognition by the lectin. A structural feature of dextran oligomers is suggested to explain this result.

The glucan-binding lectin (GBL) ofStreptococcus sobrinus is cell associated, enabling the bacteria to be aggregated by α-1,6 glucans. Glucans, such as amylose, pullulan, laminarin and nigeran, have no affinity for the lectin. High molecular weight α-1,6 glucans (dextrans) readily aggregate the bacteria, whereas low molecular weight glucans inhibit the aggregation brought about by the high molecular weight species. Methylated glucan T-2000 (an α-1,6 glucan with an average molecular weight of 2 × 106 Da) aggregated the bacteria very poorly when the extent of methylation (DS, or degree of substitution) was high, and less poorly when the DS was low. Similarly, methylated low molecular weight α-1,6 glucan was a poor inhibitor of aggregation induced by the high molecular weight glucan T-2000. Because the methylation occurred primarily on the hydroxyl of C-2, it is suggested that the hydroxyl is needed for formation of the lectin-glucan complex. It appears that the GBL is not only stereospecific in interaction with glucans, but also regiospecific, interacting only with the underivatized α-1,6-glucan.

AbstractIrradiation of the azides (I) results in the formation of the dialdoside hydrates (II).

Bacteria grow by enlarging their envelope in such a way that osmotic pressure does not normally cause physical rupture. The strategy of Bacillus subtilis for both cylindrical elongation and pole formation is now substantially defined. Side-wall growth takes place by laying down new peptidoglycan, which is then displaced outwards, stretched and discarded; cross walls are laid down in the absence of stress, and then stretched and bulged outward as the septum is split and the pole is formed.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSucrose chemistry. A synthetically useful monoarenesulfonationSujan Singh, Christopher M. Maynard, Ronald J. Doyle, and K. Grant TaylorCite this: J. Org. Chem. 1984, 49, 6, 976–981Publication Date (Print):March 1, 1984Publication History Published online1 May 2002Published inissue 1 March 1984https://pubs.acs.org/doi/10.1021/jo00180a005https://doi.org/10.1021/jo00180a005research-articleACS PublicationsRequest reuse permissionsArticle Views149Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

The pole of the Gram-positive rod Bacillus subtilis is formed by the construction of a crosswall which is then split. The newly exteriorized wall comes under stress and stretches to form the developing pole. A model is proposed to account for the even bisection of the septum. It is based on an extension of our previous finding that autolysin action on living cells is increased when the protonmotive force is dissipated in any of a number of ways. The first site of enzymatic attack is that region of the peripheral wall that has become farther removed from the cytoplasmic membrane as the result of the envagination of the developing septum. Later, enzymatic action lead to the cleavage midway between the portions of cytoplasmic membrane delimiting the septum as this region is farthest removed from the source of protonmotive force.

AbstractAus Sucrose (Ia) erhält man mit 2,4,6‐Triisopropyl‐benzolsulfonylchlorid direkt das Mono‐Substitutionsprodukt (Ib) neben geringen Anteilen des Isomeren (ll).

teichoic acid, were employed tomonitor cell surface changes during growth. Cell walls werespecifically labeled withN-acetyl- D-(H)glucosamine, andafter growth, autoradiographs were prepared forbothcell types. Thelocations of silver grains revealed that label was progressively lost fromnumerous sites on thecell cylinders, whereas label was retained on thecell poles, evenafter'several generations. Intheautolysin-deficient andchain- forming strain, itwas foundthatthedistance between densely labeled poles approximately doubled after eachgeneration ofgrowth. Intheautolysin-sufficient strain, itwas foundthatthenumbersoflabeled cell poles remained nearly constant forseveral generations, supporting thepremise thatcompleted septa and poles arelargely conserved during growth. Fluorescein-conjugated concanavalin A was alsousedto determine thedistribution ofat-D-glucosylated teichoic acid on thesurfaces ofgrowing cells. Strains with temperature-sensitive phosphoglucomutase were usedbecause inthesemutants, glycosylation ofcellWall teichoic acids canbecontrolled bytemperature shifts. Whenthebacteria were grownat45°C, whichstops theglucosylation ofteichoic acid, thecells gradually lost their ability tobindconcanavalin A on their cylindrical surfaces, buttheyretained concanavalin A-reactive sites on their poles. Discrete areason the cylinder, defined by'thebinding offluorescent concanavalin A,were absentwhen thesynthesis of glucosylated teichoic acidwas inhibited during growth forseveral generations atthenonpermissive temperature. Whenthemutantwas shifted fromanonpermissive toapermissive temperature, all areasof thecylinder becameable tobindthelabeled concanavalin A after aboutone-half generation. Oldcellpoles were able tobindthelectin after nearly onegeneration atthepermissive temperature, showing that new wall synthesis doesoccurinthecell poles, although itoccursslowly. Thesedata, basedon bothqualitative and quantitative experiments, support amodelforcell wallassembly inB.subtilis, inwhichcylinders elongate byinside-to-outside growth, withdegradation ofthestress-bearing oldwallinwild-type organisms. Lossof wallmaterial, byturnover, frommany sites on thecylinder may benecessaryforintercalation ofnew wall andnormal length extension. Poles tend toretain their wallcomponents during division andareturned over muchmore slowly. Itisnowclear that somebacteria, suchasStreptococcus faecalis (faecium), exhibit cell wall growth fromdiscrete and well-defined zones. Eachunit cell splits its wallbandasit initiates cell division, forming twonewbands ofwallmateri- alwhichaccompany anddelineate cell enlargement. The bands areformed atthebeginning ofagrowth cycle andcan beusedasmorphological markers tomonitor cell cycle- related events (14). Bacilli, particularly Oacillus subtilis, appear tohavemorecomplex modesofwallreplication. There areconflicting reports withrespect tohowwalls are assembled inbacilli (2,11-13, 16,30,44). Somereports suggest atotally diffuse mode,inwhich manynascent wall insertion sites areinvolved. Still others, including therecent workofSchlaeppi andcolleagues (52, 57), propose that wall synthesis inB.subtilis occurs fromseveral sites inthe cylinder. Wallsynthesis occurs inaradial direction (new wallisdeposited inside andoldwallonlyisfoundoutside) during growth (2,21,50,51). Wallbandsalso appear tobe present whenexamined carefully withseveral fixatives (1, 9).Thesewallbands, however, donotmigrate intothe cylindrical regions ofthecell, andtheytendtodisappear as elongation occurs. Another important complication inas-

Spores from severalBacillus species displayed a strong affinity for hexadecane and other hydrophobic solvents. The binding ofBacillus subtilis spore suspensions to octyl-Sepharose was enhanced by ammonium sulfate and other salts, but was inhibited by detergents. Treatment of spore suspensions with strong denaturants promoted their adherence to hexadecane, presumably by exposing hydrophobic residues in coat proteins. The hydrophobic characteristics of spores may be important in the ecological adaptation of certain bacteria.

The cell surface of Bacillus subtilis contains several peptidoglycan-associated polypeptides. Cell walls were labeled with 125I or 35S, and the products were digested with lysozyme. When the digests were chromatographed on Sephacryl S-200, peaks of radioactivity corresponding to molecular weights of 240,000, 125,000, 20,000, 17,000, and 15,000 were observed. The walls solubilized by lysozyme were also subjected to sodium dodecyl sulfate-poly(acrylamide) gel electrophoresis, and radioactive bands corresponding to apparent molecular weights of 24,000, 22,000, and 19,000 were found. Isoelectric focusing of the digests revealed the presence of a component having an isoelectric point of 3.7, and, possibly, of minor components having isoelectric points of 4.7 and 6.1. Proteases, including trypsin, subtilisin, and pronase, removed some of the radioactivity from [35S]-labeled walls. Significant proportions of label from [35S]walls were solubilized by the peptide-bond-breaking agents cyanogen bromide and N-bromosuccinimide. Small proportions of radioactivity were released from labeled walls by hydroxylamine and trichloroacetic acid. Direct, amino acid analyses of the walls showed the presence of several amino acids not commonly regarded as constituents of peptidoglycan. Cell walls from a protease-deficient mutant, and from a wall preparation enriched in cell poles, contained similar proportions of amino acids. In addition, wall preparations from an autolysin-deficient mutant, and walls from protease hyper-producing strains, contained amino acids that could not be removed by rigorous extraction-procedures. The results suggest that the cell walls of Bacillus subtilis contain tightly, or covalently, bound protein molecules or polypeptides that are refractory to removal by denaturants.

Soluble glucan synthesis catalyzed by dextransucrase preparations from Streptococcus mutans 6715 were inhibited by pyridoxal-5-phosphate and several other pyridine analogs, including pyridoxine, pyridoxamine, pyridoxamine-5-phosphate, pyridoxal, and 4-pyridoxic acid. Pyridine and pyridine-4-carboxaldehyde were not effective inhibitors of the enzyme. Kinetic analyses suggested that pyridoxal-5-phosphate is a noncompetitive inhibitor of dextransucrase. The inactivation was dependent on time, pyridoxal-5-phosphate concentration, and hydrogen ion concentration. Apparent Ki values were 4.9 mM at pH 7.0 and 4.2 mM at pH 5.5. Dextransucrase activity could be restored by dialysis to remove the inhibitors. Maximum inhibition was observed after a 120-min incubation of the enzyme with pyridoxal-5-phosphate. The pH optima for inhibition by pyridoxal-5-phosphate were 4 and 7. The sucrose-dependent adherence of S. mutans cells to saliva-coated hydroxylapatite beads was also inhibited by pyridoxal-5-phosphate but only marginally by the other pyridine anatogs. In addition, pyridoxal-5-phosphate markedly reduced the rate of acid production by intact S. mutans cells from sucrose or glucose substrates. Another pyridoxal-5-phosphate analog, 2-methyl-5-hydroxypyridine, was also effective in preventing the production of acid by S. mutans from sucrose or glucose. When S. mutans cells were preincubated with pyridoxal-5-phosphate or pyridine analogs, significant reductions in the rate of D-glucose uptake were observed. It is suggested that the inhibition of dextransucrase occurs because of a change iun enzyme conformation which results from the binding of the pyridine derivatives. The results suggest that pyridoxal-5-phosphate or structural analogs may ultimately be useful in reducing the incidence of dental caries.

The shapes of many prokaryotes can be understood by the assumption that the cell wall expands in response to tension created by the osmotically derived hydrostatic pressure. Different organisms have different shapes because wall growth takes place in different regions. A previous paper (Koch et al., 1981 a) considered the simplest case of prokaryotic growth, i.e. that of Streptococcus faecium. In the present paper, an elaboration of this theory is applied to two further cases - the more perfectly spherical cocci and the rod-shaped bacteria. These cases are more complex mathematically, because growth over a considerable fraction of the surface must be considered. Such diffuse growth cannot be treated analytically, but can be simulated on a computer or handled by geometric arguments. The spherical form of the cocci may result from either diffuse growth over their entire external surface, or from zonal growth in which the addition of new material only occurs in the immediate vicinity of the splitting septum. In the zonal model, it must be assumed that the least amount of previously laid down septal peptidoglycan consistent with wall growth is reworked in the formation of the new external wall. For Gram-positive rods, where the body of the rod is truly cylindrical, three kinds of growth zones are required: (1) the inward edge of the ingrowing septum, (2) the junction of septum and nascent pole, and (3) the cylindrical walls. Two modes for cylindrical elongation ara possible: (a) new wall is added in one or a few narrow annular zones, or (b) new wall material is added continuously all over the innermost surface and the outer layer is degraded. It is shown that the latter case applies to Bacillus subtilis. Also summarized in this paper are results, developed in more detail elsewhere, concerning the morphology of fusiform bacteria, Gram-negative rods and the hyphal tips of fungi.