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Strain BC640 T was isolated from site CSC13 from a darkgreen biofilm by using the adhesive tape (Fungi Tape DID) technique (Urzì & De Leo, 2001). Growth of colonies (quantified as the number of c.f.u. per cm 2 of adhesive tape) was carried out on R2A medium (Reasoner & Geldreich, 1985) at 28 u C for 15 days. Ten to 20 colonies were selected randomly, preliminarily characterized after transferring to tryptic soy agar (TSA; BBL) and subsequently maintained on yeast extract-malt extract agar [International Streptomyces Project (ISP) medium 2] (Shirling & Gottlieb, 1966).Genomic DNA was extracted as described by Everest & Meyers (2008). The 16S rRNA gene was amplified as described by Cook & Meyers (2003), the gyrB gene as described by Kirby et al. (2010) and the atpD, recA, relA and rpoB genes as described by Curtis & Meyers (2012). Approximately 500 ng template DNA was used in the PCR amplification of the 16S rRNA and gyrB genes, with 1 mg DNA being used for amplification of the atpD, recA, relA and rpoB genes. PCR products were purified using an MSB Spin PCRapace kit (Invitek) and sequenced (Macrogen). Sequence analysis was performed using DNAMAN version Abbreviations: DDH, DNA-DNA hybridization; MLSA, multilocus sequence analysis.The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA, atpD, gyrB, recA, relA and rpoB gene sequences of strain BC640

No abstract

A novel actinobacterium, strain BC637 T , was isolated from a biodeteriogenic biofilm sample collected in 2009 in the Saint Callixstus Roman catacomb. The strain was found to belong to the genus Kribbella by analysis of the 16S rRNA gene. Phylogenetic analysis using the 16S rRNA gene and the gyrB, rpoB, relA, recA and atpD concatenated gene sequences showed that strain BC637 T was most closely related to the type strains of Kribbella lupini and Kribbella endophytica. DNA-DNA hybridization experiments confirmed that strain BC637 T is a genomic species that is distinct from its closest phylogenetic relatives, K. endophytica DSM 23718 T (63 % DNA relatedness) and K. lupini LU14 T (63 % DNA relatedness). Physiological comparisons showed that strain BC637 T is phenotypically distinct from the type strains of K. endophytica and K. lupini. Thus, strain BC637 T represents the type strain of a novel species, for which the name Kribella italica sp. nov. is proposed (5DSM 28967 T 5NRRL B-59155 T).

The strategic redesign of microbial biosynthetic pathways is a compelling route to access molecules of diverse structure and function in a potentially environmentally sustainable fashion. The promise of this approach hinges on an improved understanding of acyl carrier proteins (ACPs), which serve as central hubs in biosynthetic pathways. These small, flexible proteins mediate the transport of molecular building blocks and intermediates to enzymatic partners that extend and tailor the growing natural products. Past combinatorial biosynthesis efforts have failed due to incompatible ACP−enzyme pairings. Herein, we report the design of chimeric ACPs with features of the actinorhodin polyketide synthase ACP (ACT) and of the Escherichia coli fatty acid synthase (FAS) ACP (AcpP). We evaluate the ability of the chimeric ACPs to interact with the E. coli FAS ketosynthase FabF, which represents an interaction essential to building the carbon backbone of the synthase molecular output. Given that AcpP interacts with FabF but ACT does not, we sought to exchange modular features of ACT with AcpP to confer functionality with FabF. The interactions of chimeric ACPs with FabF were interrogated using sedimentation velocity experiments, surface plasmon resonance analyses, mechanism-based cross-linking assays, and molecular dynamics simulations. Results suggest that the residues guiding AcpP−FabF compatibility and ACT−FabF incompatibility may reside in the loop I, α-helix II region. These findings can inform the development of strategic secondary element swaps that expand the enzyme compatibility of ACPs across systems and therefore represent a critical step toward the strategic engineering of "un-natural" natural products.