Purified bovine brain phosphatidylinositol 3-kinase (Pl3-kinase) is composed of 85 kd and 110 kd subunits. The 85 kd subunit (p85 alpha) lacks Pl3-kinase activity and acts as an adaptor, coupling the 110 kd subunit (p110) to activated protein tyrosine kinases. Here the characterization of the p110 subunit is presented. cDNA cloning reveals p110 to be a 1068 aa protein related to Vps34p, a S. cerevisiae protein involved in the sorting of proteins to the vacuole. p110 expressed in insect cells possesses Pl3-kinase activity and associates with p85 alpha into an active p85 alpha-p110 complex that binds the activated colony-stimulating factor 1 receptor. p110 expressed in COS-1 cells is catalytically active only when complexed with p85 alpha.

Affinity-purified bovine brain phosphatidylinositol 3-kinase (PI3-kinase) contains two major proteins of 85 and 110 kd. Amino acid sequence analysis and cDNA cloning reveals two related 85 kd proteins (p85 alpha and p85 beta), which both contain one SH3 and two SH2 regions (src homology regions). When expressed, these 85 kd proteins bind to and are substrates for tyrosine-phosphorylated receptor kinases and the polyoma virus middle-T antigen/pp60c-src complex, but lack PI3-kinase activity. However, an antiserum raised against p85 beta immunoprecipitates PI3-kinase activity. The active PI3-kinase complex containing p85 alpha or p85 beta and the 110 kd protein binds to PDGF but not EGF receptors. p85 alpha and p85 beta may mediate specific PI3-kinase interactions with a subset of tyrosine kinases.

, and OXA-type ␤-lactamases were studied by PCR with 124 ampicillin-resistant (AMP r ) Escherichia coli isolates recovered from foods of animal origin (n ‫؍‬ 20) and feces of humans (n ‫؍‬ 49) and healthy animals (n ‫؍‬ 55). PCR showed that 103 isolates were positive for TEM and negative for SHV and OXA. Three E. coli isolates showed a positive reaction for OXA, and one showed a positive reaction for SHV. The remaining 17 E. coli isolates were negative for the three enzymes by PCR. Fifty-seven of the 103 bla TEM amplicons were sequenced. Different molecular variants of bla TEM-1 were found in 52 isolates: bla TEM-1a (n ‫؍‬ 9), bla TEM-1b (n ‫؍‬ 36), bla TEM-1c (n ‫؍‬ 6), and bla TEM-1f (n ‫؍‬ 1). Four inhibitor-resistant TEM (IRT) ␤-lactamase-encoding genes were also detected: bla TEM-30c (IRT-2), bla TEM-34b (IRT-6), bla TEM-40b (IRT-11), and bla TEM-51a (IRT-15). A new bla TEM gene, named bla TEM-95b , which showed a mutation in amino acid 145 (P3A) was detected. It was found in a food isolate of chicken origin (AMP r , amoxicillin-clavulanic acid susceptible). The promoter region in 24 bla TEM amplicons was analyzed, and the weak P3 promoter was found in 23 of them (bla TEM-1 in 20 amplicons and bla TEM-51a , bla TEM-30c , and bla TEM-95b in 1 amplicon each). The strong Pa/Pb promoter was found only in the bla TEM-34b gene. No extended-spectrum ␤-lactamases were detected. Mutations at position ؊42 or ؊32 in the ampC gene promoter were demonstrated in 4 of 10 E. coli isolates for which the cefoxitin MIC was >16 g/ml. Different variants of bla TEM-1 and IRT bla TEM genes were found among the AMP r E. coli isolates from foods and the feces of humans and healthy animals, and a new gene, bla TEM-95b (P3), was detected.

Red wine amino acids and volatile compounds were analyzed before and after malolactic fermentation carried out by four different starter cultures of the species Oenococcus oeni and Lactobacillus plantarum. The purpose of this study was to determine whether differences can be attributed to the lactic acid bacteria strain used in this important step of the wine-making process. The malolactic cultures selected for this study were indigenous wine lactic acid bacteria strains. The data were evaluated using different multivariate analysis techniques. Results showed different malolactic behaviors for O. oeni and L. plantarum and significant metabolic differences between both species. A degree of diversity was found within each lactic acid bacteria group, since wines presented specific characteristics depending on the lactic acid bacteria strain used. In all cases, malolactic fermentation seemed to modify the amino acid and volatile composition of the wine.