The enzymatic activity of salivary amylase bound to the surface of several species of oral streptococci was determined by the production of acid from starch and by the degradation of maltotetraose to glucose in a coupled, spectrophotometric assay. Most strains able to bind amylase exhibited functional enzyme on their surface and produced acid from the products of amylolytic degradation. These s...

Insulator-based dielectrophoresis can be used to manipulate biological particles, but has thus far found limited practical applications due to low sensitivity. We present linear sweep three-dimensional insulator-based dielectrophoresis as a considerably more sensitive approach for strain-level discrimination bacteria. In this work, linear sweep three-dimensional insulator-based dielectrophoresi...

In present study, methanol extracts of the Chlorophycean group of seaweeds have been tested for their antibacterial activity against oral bacteria causing dental caries. Different concentrations of the extracts of the four species of seaweedsChaetomorpha antennina, Cladophora fascicularis, Spongomorpha indica and Ulva fasciata collected from sea coast of Visakhapatnam have been tested for their...

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 glycoprote...

UNLABELLED Amazonian biodiversity products that have been used for years in folk medicine, have emerged as feasible and promising alternatives for the inhibition of microorganisms in dental biofilm. Copaiba oil, a phytotherapic agent widely used by the Amazonian populations, is known for its antibacterial, anti-inflammatory, anesthetic, healing and antitumor medicinal properties. OBJECTIVE Th...

The amino acid sequence requirements in the hinge of human immunoglobulin A1 (IgA1) for cleavage by IgA1 proteases of different species of Streptococcus were investigated. Recombinant IgA1 antibodies were generated with point mutations at proline 227 and threonine 228, the residues lying on either side of the peptide bond at which all streptococcal IgA1 proteases cleave wild-type human IgA1. Th...

Diverse Streptococcus species including Streptococcus Pneumoniae, Sanguis, Gordonii, Mitis and Mutans cause life-threatening conditions including pneumonia, bacteremia and meningitis. These diseases bear a high morbidity and mortality and for this reason, understanding the key events in the pathogenesis of these infections have a great significance in their prevention and/or treatment. Here, we...

Streptococcus mitisfrequently causes invasive infections in neutropenic cancer patients, with a subset of patients developing viridans group streptococcal (VGS) shock syndrome. We report here the first complete genome sequence ofS. mitisstrain SVGS_061, which caused VGS shock syndrome, to help elucidate the pathogenesis of severe VGS infection.

The activity of trovafloxacin was compared with those of vancomycin and penicillin in a model of Streptococcus sanguis species group (trovafloxacin MIC, 0.125 microg/ml) and Streptococcus mitis species group (trovafloxacin MIC, 0.125 microg/ml) experimental endocarditis. Rabbits with catheter-induced aortic valve vegetations were given no treatment, trovafloxacin at 15 mg/kg of body weight thre...

We evaluated the applicability of ply PCR for confirmation of the identification of Streptococcus pneumoniae. lytA PCR, 16S rRNA sequencing, and amplified-fragment length polymorphism were used as reference methods. In contrast to the lytA gene, the ply gene proved to be not specific for S. pneumoniae. The presence of the ply gene in other streptococci, in particular Streptococcus mitis, sugges...