Binding of Host-Associated Treponeme Proteins to Collagens and Laminin: A Possible Mechanism of Spirochetal Adherence to Host Tissues

The polypeptides of seven strains of human treponemes were investigated by immunoblot analysis for their binding to the human placental collagens and laminin. Of the treponemal polypeptides, eleven polypeptides, 45-kDa, 49-kDa, and 62-kDa polypeptides from T. pallidum ATCC 27087, a 48-kDa polypeptide from T. phagedenis biotype Reiter, 51-kDa and 53-kDa polypeptides from T. vincentii ATCC 35580, 30-kDa, 53-kDa and 63-kDa polypeptides from T. socranskii subsp. buccale ATCC 35534, a 52-kDa polypeptide from T. denticola ATCC 35405, and a 53-kDa polypeptide from T. denticola ATCC 33520 possessed an ability to bind to the laminin, type I, III, IV, or V collagen. An intermediate-sized human oral isolate strain G7201 did not possess any laminin- or collagen-binding polypeptides. Immunoelectron microscopy using intact treponemal cells with a single collagen-binding polypeptide and the corresponding antisera demonstrated that the 51-kDa and 53-kDa polypeptides from T. vincentii, the 53-kDa polypeptide from T. socranskii subsp. buccale ATCC 35534 and the 52-kDa polypeptide from T. denticola ATCC 35405, were outer envelope proteins.     

Fibronectin-Binding Proteins of a Human Oral Spirochete Treponema denticola

Major polypeptides from a human oral spirochete Treponema denticola ATCC 33520 were examined to demonstrate their ability to bind to human plasma fibronectin by immunoblot analysis. Of three main polypeptides separated on sodium dodecyl sulfate polyacrylamide gels 53,000-daltons (53-kDa) and 72-kDa surface antigenic proteins and a 38-kDa axial flagellar protein showed the ability to bind to fibronectin, suggesting that fibronectin on host cells can mediate cytoadherence of T. denticola by its binding to the surface proteins or the exposed 38-kDa axial flageller protein.     

Occurrence of 2-keto-3-deoxyoctonate (KDO) and KDO phosphate in lipopolysaccharides ofBacteriodes species

Occurrence of 2-keto-3-deoxyoctonate (KDO) in lipopolysaccharides (LPS) of genusBacteroides (some strains have recently been reclassified asPorphyromonas orPrevotella) was examined. Strong-acid treatment of LPS isolated fromBacteroides fragilis, Bacteroides (Porphyromonas) gingivalis andBacteroides intermedius, (Prevotella intermedia) released periodate/thiobarbituric acid reaction-positive substances that were not detectable under conventional hydrolysis conditions. These substances were demonstrated to be KDO phosphate by high voltage paper electrophoresis before and after alkaline phosphatase treatment. KDO phosphate was also identified in these LPS by gas-liquid chromatography and gas-liquid chromatography/mass spectrometry. KDO was identified as well in both mild and strong-acid hydrolysates of LPS isolated fromBacteriodes melaninogenicus (Prevotella melaninogenica). Neither KDO nor KDO phosphate was detectable in LPS ofBacteriodes asaccharolyticus (Porphyromonas asaccharolytica) even after the strong-acid treatment of LPS. These findings indicate that there are possible structural variations in the inner core region ofBacteroides LPS.     

Isolation,partial purification and preliminary characterization of a bacteriocin from Streptococcus mutans Rm-10

An extracellular bactericidal substance was isolated from the supernatant of Streptococcus mutans Rm-10 culture fluid and partially purified with 60% ammonium sulfate precipitation, differential centrifugation, and gel filtration on Sephadex G-200. There was a good correlation of the sensitivity profiles of indicator strains whether assayed on solid medium or with purified material from cell-free culture fluid, indicating that the same inhibitory substance is produced on solid medium and in broth. Vapor from organic solvents such as chloroform, acetone, ethanol, and ether as well as heat treatment at 100 degrees C for 30 min had little effect on the bactericidal factor. It was sensitive to trypsin and pronase and resistant to deoxyribonuclease, ribonuclease, lysozyme, and phospholipase C. The inhibitor was not infective, and electron microscopic studies failed to reveal phage or phage-like particles in concentrated solutions of the bactericidal material. The results indicate that the extracellular bactericidal substance is indeed a bacteriocin. Activity in broth cultures reached a maximum only after exponential growth had ceased. It was active against other streptococcal strains as well as strains of Actinomyces naeslundii, A. viscosus, Bacillus subtilis and Staphylococcus aureus, but not against strains of Fusobacterium nucleatum and Escherichia coli.     

Lanthionine as an essential constituent of cell wall peptidoglycan ofFusobacterium nucleatum

Lanthionine, a sulfur-containing diamino acid which had not previously been reported as one of the main amino acids of any bacterial cell wall peptidoglycan, was demonstrated inFusobacterium nucleatum peptidoglycan isolated by sodium dodecyl sulfate extraction and protease digestion. Lysine, diaminopimelic acid, and ornithine were absent. Lanthionine seems to be an essential dibasic amino acid, involved in cross-linkages betwen stem peptide subunits inF. nucleatum.     

The effects of habitat fragmentation on persistence of source-sink metapopulations in systems with predators and prey or apparent competitors.

We consider systems with one predator and one prey, or a common predator and two prey species (apparent competitors) in source and sink habitats. In both models, the predator species is vulnerable to extinction, if productivity in the source is insufficient to rescue demographically deficient sink populations. Conversely, in the model with two prey species, if the source is too rich, one of the prey species may be driven extinct by apparent competition, since the predator can maintain a large population because of the alternative prey. Increasing the rate of predator movement from the source population has opposite effects on prey and predator persistence. High emigration rate exposes the predator population to danger of extinction, reducing the number of individuals that breed and produce offspring in the source habitat. This may promote coexistence of prey by relaxing predation pressure and apparent competition between the two prey species. The number of sinks and spatial arrangement of patches, or connectivity between patches, also influence persistence of the species. More sinks favor the prey and fewer sinks are advantageous to the predator. A linear pattern with the source at one end is profitable for the predator, and a centrifugal pattern in which the source is surrounded by sinks is advantageous to the prey. When the dispersal rate is low, effects of the spatial structure may exceed those of the number of sinks. In brief, productivity in patches and patterns of connectivity between patches differentially influence persistence of populations in different trophic levels.     

Can Systems Biology Understand Pathway Activation? Gene Expression Signatures as Surrogate Markers for Understanding the Complexity of Pathway Activation

Cancer is thought to be caused by a sequence of multiple genetic and epigenetic alterations which occur in one or more of the genes controlling cell cycle progression and signaling transduction. The complexity of carcinogenic mechanisms leads to heterogeneity in molecular phenotype, pathology, and prognosis of cancers.     

Amplification of C1027-induced DNA cleavage and apoptosis by a quinacrine-netropsin hybrid molecule in tumor cell lines

We examined the effect of a newly synthesized DNA-binding ligand, quinacrine-netropsin hybrid molecule (QN), on cytotoxicity, apoptosis, and DNA strand breaks induced by an enediyne antitumor antibiotic, C1027. QN significantly enhanced C1027-induced cellular DNA strand breaks, caspase-3 activation, and DNA ladder formation, characteristic of apoptosis, in human HL-60 cells. Flow cytometry revealed that C1027-induced intracellular H(2)O(2) generation was enhanced by QN, suggesting that QN enhances C1027-induced cytotoxic effect through H(2)O(2)-mediated apoptosis. QN also significantly enhanced C1027-induced apoptosis in BJAB cells, and the inhibition of apoptosis was observed in BJAB cells transfected with Bcl-2 gene. The experiment using (32)P-labeled DNA fragments showed that the addition of QN enhanced C1027-induced double-stranded DNA cleavage at the 5'-AGG-3'/3'-TCC-5' sequence (cutting sites are underlined). These results suggest that QN enhances C1027-induced antitumor effect via DNA cleavage and apoptosis. The present study shows a novel approach to the potentially effective anticancer therapy.