Characterization of fatty acid modifying enzyme activity in staphylococcal mastitis isolates and other bacteria

<p>Abstract</p> <p>Background</p> <p>Fatty acid modifying enzyme (FAME) has been shown to modify free fatty acids to alleviate their bactericidal effect by esterifying fatty acids to cholesterol or alcohols. Although it has been shown in previous studies that FAME is required for <it>Staphylococcus aureus</it> survival in skin abscesses, FAME is poorly studied compared to other virulence factors. FAME activity had also been detected in coagulase-negative staphylococci (CNS). However, FAME activity was only surveyed after a bacterial culture was grown for 24 h. Therefore if FAME activity was earlier in the growth phase, it would not have been detected by the assay and those strains would have been labeled as FAME negative.</p> <p>Results</p> <p>Fifty CNS bovine mastitis isolates and several <it>S. aureus, Escherichia coli</it>, and <it>Streptococcus uberis</it> strains were assayed for FAME activity over 24 h. FAME activity was detected in 54% of CNS and 80% <it>S. aureus</it> strains surveyed but none in <it>E. coli</it> or <it>S. uberis</it>. While some CNS strains produced FAME activity comparable to the lab strain of <it>S. aureus</it>, the pattern of FAME activity varied among strains and across species of staphylococci. All CNS that produced FAME activity also exhibited lipase activity. Lipase activity relative to colony forming units of these CNS decreased over the 24 h growth period. No relationship was observed between somatic cell count in the milk and FAME activity in CNS.</p> <p>Conclusions</p> <p>Some staphylococcal species surveyed produced FAME activity, but <it>E. coli</it> and <it>S. uberis</it> strains did not. All FAME producing CNS exhibited lipase activity which may indicate that both these enzymes work in concert to alter fatty acids in the bacterial environment.</p

Analysis of the genome sequence of the flowering plant Arabidopsis thaliana

The flowering plant Arabidopsis thaliana is an important model system for identifying genes and determining their functions. Here we report the analysis of the genomic sequence of Arabidopsis. The sequenced regions cover 115.4 megabases of the 125-megabase genome and extend into centromeric regions. The evolution of Arabidopsis involved a whole-genome duplication, followed by subsequent gene loss and extensive local gene duplications, giving rise to a dynamic genome enriched by lateral gene transfer from a cyanobacterial-like ancestor of the plastid. The genome contains 25,498 genes encoding proteins from 11,000 families, similar to the functional diversity of Drosophila and Caenorhabditis elegans - the other sequenced multicellular eukaryotes. Arabidopsis has many families of new proteins but also lacks several common protein families, indicating that the sets of common proteins have undergone differential expansion and contraction in the three multicellular eukaryotes. This is the first complete genome sequence of a plant and provides the foundations for more comprehensive comparison of conserved processes in all eukaryotes, identifying a wide range of plant-specific gene functions and establishing rapid systematic ways to identify genes for crop improvement