Milk processing plant isolates adherence.

<p>The percentage of isolates within each genus exhibiting a given phenotype is shown with the number of isolates tested in parentheses. Little or no adhesion (0/+), medium to high production (++/+++).</p

Lecithinase production by milk processing plant isolates.

<p>The percentage of isolates within each genus exhibiting a given phenotype is shown with the number of isolates tested in parentheses. Little or no production (0/+), medium to high production (++/+++), and no growth on assay medium (ND).</p

Characterization of the isolates biofilm.

<p>Biofilm formation capacity (in TSB) and composition in terms of total mass (Mass) and cells per mass (Specific Respiratory Activity, SRA). Isolates (2 digit labels) sorted by sampling site and genus (ST  =  Storage Tank). Ste - <i>Stenotrophomonas</i> spp.; Sta - <i>Staphylococcus</i> spp.; Ser - <i>Serratia</i> spp.; Pse - <i>Pseudomonas</i> spp. Values correspond to the optical density (OD measured (mass - OD at 570 nm; SRA - 570 nm/490 nm).</p

Microbial isolate profile from a sanitized milk processing line.

<p>Microorganisms isolates recovered in total from the sampling sites (T) distributed by location: storage tank (A), junction between the storage tank and the transfer pump (B), holding cell (C) and inner part of the pasteurizer (D). Microorganisms belonging to the genera <i>Achromobacter, Brevibacterium, Cupriavidus, Ochrobactrum, Raoultella</i> and <i>Rhodococcus</i> were listed as "other". The number of isolates is indicated within each pie segment. (T) Total isolates obtained from all samples organized by genus; (A–D) Breakdown of isolate distribution per sampling site.</p

Siderophore secretion by milk processing plant isolates.

<p>The percentage of isolates within each genus exhibiting a given phenotype is shown with the number of isolates tested in parentheses. Little or no production (0/+), medium to high production (++/+++), and no growth on assay medium (ND).</p

Protease production by milk processing plant isolates.

<p>The percentage of isolates within each genus exhibiting a given phenotype is shown with the number of isolates tested in parentheses. Little or no production (0/+), medium to high production (++/+++), and no growth on assay medium (ND).</p

Antimicrobial production by milk processing plant isolates against <i>E. coli</i> or <i>S. aureus</i>.

<p>The percentage of isolates within each genus exhibiting a given phenotype is shown with the number of isolates tested in parentheses. Antimicrobials were produced (P), or not produced (N).</p

Mixing and Matching Siderophore Clusters: Structure and Biosynthesis of Serratiochelins from <i>Serratia sp.</i> V4

Interrogation of the evolutionary history underlying the remarkable structures and biological activities of natural products has been complicated by not knowing the functions they have evolved to fulfill. Siderophoressoluble, low molecular weight compoundshave an easily understood and measured function: acquiring iron from the environment. Bacteria engage in a fierce competition to acquire iron, which rewards the production of siderophores that bind iron tightly and cannot be used or pirated by competitors. The structures and biosyntheses of “odd” siderophores can reveal the evolutionary strategy that led to their creation. We report a new <i>Serratia</i> strain that produces serratiochelin and an analog of serratiochelin. A genetic approach located the serratiochelin gene cluster, and targeted mutations in several genes implicated in serratiochelin biosynthesis were generated. Bioinformatic analyses and mutagenesis results demonstrate that genes from two well-known siderophore clusters, the <i>Escherichia coli</i> enterobactin cluster and the <i>Vibrio cholera</i> vibriobactin cluster, were shuffled to produce a new siderophore biosynthetic pathway. These results highlight how modular siderophore gene clusters can be mixed and matched during evolution to generate structural diversity in siderophores