Streptococcus pyogenes infection of tonsil explants is associated with a human β-defensin 1 response from control but not recurrent acute tonsillitis patients.

Host defence peptides (HDP), including the defensins and hCAP-18, function as part of the innate immune defences, protecting the host epithelia from microbial attachment and invasion. Recurrent acute tonsillitis (RAT), in which patients suffer repeated symptomatic tonsil infections, is linked to Streptococcus pyogenes, a group A streptococcus, and may reflect the impaired expression of such peptides. To address this, the defensin and hCAP-18 messenger RNA expression profiles of 54 tonsils excised from control and RAT patients undergoing tonsillectomy were quantified and compared.

Roles of minor pilin subunits Spy0125 and Spy0130 in the serotype M1 Streptococcus pyogenes strain SF370.

Adhesive pili on the surface of the serotype M1 Streptococcus pyogenes strain SF370 are composed of a major backbone subunit (Spy0128) and two minor subunits (Spy0125 and Spy0130), joined covalently by a pilin polymerase (Spy0129). Previous studies using recombinant proteins showed that both minor subunits bind to human pharyngeal (Detroit) cells (A. G.

Pili mediate specific adhesion of Streptococcus pyogenes to human tonsil and skin.

Very little is known about the biological functions of pili that have recently been found to be expressed by important Gram-positive pathogens such as Corynebacterium diphtheriae, Streptococcus agalacticae, S. pneumoniae and S. pyogenes.

Isolation and function of the amino acid transporter PAT1 (slc36a1) from rabbit and discrimination between transport via PAT1 and system IMINO in renal brush-border membrane vesicles.

Reabsorption of amino acids is an important function of the renal proximal tubule. pH-dependent amino acid transport has been measured previously using rabbit renal brush-border membrane vesicles (BBMV). The purpose of this investigation was to determine whether this pH-dependent uptake represents H(+)/amino acid cotransport via a PAT1-like transport system.

Vigabatrin transport across the human intestinal epithelial (Caco-2) brush-border membrane is via the H+ -coupled amino-acid transporter hPAT1.

The aim of this investigation was to determine if the human proton-coupled amino-acid transporter 1 (hPAT1 or SLC36A1) is responsible for the intestinal uptake of the orally-administered antiepileptic agent 4-amino-5-hexanoic acid (vigabatrin). The Caco-2 cell line was used as a model of the human small intestinal epithelium. Competition experiments demonstrate that [3H]GABA uptake across the apical membrane was inhibited by vigabatrin and the GABA analogues trans-4-aminocrotonic acid (TACA) and guvacine, whereas 1-(aminomethyl)cyclohexaneacetic acid (gabapentin) had no affect.

Diverging regulation of pyruvate dehydrogenase kinase isoform gene expression in cultured human muscle cells.

The pyruvate dehydrogenase complex occupies a central and strategic position in muscle intermediary metabolism and is primarily regulated by phosphorylation/dephosphorylation. The identification of multiple isoforms of pyruvate dehydrogenase kinase (PDK1-4) and pyruvate dehydrogenase phosphatase (PDP1-2) has raised intriguing new possibilities for chronic pyruvate dehydrogenase complex control. Experiments to date suggest that PDK4 is the major isoenzyme responsible for changes in pyruvate dehydrogenase complex activity in response to various different metabolic conditions.

Ryanodine receptor oligomeric interaction: identification of a putative binding region.

Specific interactions between adjacent ryanodine receptor (RyR) molecules to form ordered two-dimensional arrays in the membrane have been demonstrated using electron microscopy both in situ, in tissues and cells, and in vitro, with the purified protein. RyR interoligomeric association has also been inferred from observations of simultaneous channel gating during multi-RyR channel recordings in lipid bilayers. In this study, we report experiments designed to identify the region(s) of the RyR molecule, participating in this reciprocal interaction.