Novel Natural Products from Soil DNA Libraries in a Streptomycete Host

Abstract

As a route to accessing the potential chemical diversity of uncultivable microbes from the soil, combinatorial biosynthetic libraries were constructed by cloning large fragments of DNA isolated from soil into a Streptomyces lividans host. Four novel compounds, terragines A (1), B (2), C (3), and D (4), were isolated from recombinant 436-s4-5b1, and another novel compound, terragine E (5), was isolated from 446-s3-102g1. The structures were determined by a combination of spectroscopic techniques, primarily 2D NMR.

Construction of soil environmental DNA cosmid libraries and screening for clones that produce biologically active small molecules

“…Even though most bacteria are not readily cultured in the laboratory, it is possible to extract microbial DNA directly from the naturally occurring consortia of bacteria present in environmental samples (environmental DNA (eDNA)). Introduction of this previously inaccessible genetic material into easily cultured bacterial hosts provides one means to access the biosynthetic potential of uncultured bacteria [3][4][5][6][7][8][9][10][11][12][13] . Culture-independent analysis of the genetic and biochemical diversity present in naturally occurring bacterial communities, which began in the 1990s (see refs.…”

Contemporary molecular tools in microbial ecology and their application to advancing biotechnology

“…The general design principle applied to identifying gene cluster for natural biosynthetic pathway is more or less similar to that applied for identification of discrete enzymes using sequence-and function-based screening methods. The most common heterologous hosts used for the construction of metagenomic clone libraries have been Streptomyces (Wang, Graziani et al 2000) and…”

From bacterial genomics to metagenomics: concept, tools and recent advances

“…Enhancing expression of genes in metagenomic libraries may lead to discovery of a wide array of natural products. This may be achieved by taking libraries to alternate hosts such as Steptomyces [90], Bacillus, Rhizobium, Pseudomonas [54] etc. and has been the basis for discovery of antibiotic terragine [90].…”

“…This may be achieved by taking libraries to alternate hosts such as Steptomyces [90], Bacillus, Rhizobium, Pseudomonas [54] etc. and has been the basis for discovery of antibiotic terragine [90]. In addition, novel shuttle vectors that would facilitate the simultaneous expression of environmental DNA in alternative hosts are currently being investigated [80].…”

“…Sequencing of this active metagenomic clone revealed that though the genetic organization of the biosynthetic operon was similar to that of a known violacein producer, Chromobacterium violaceum, the sequence of the genes showed differences suggesting that the metagenomic clone was derived from some other organism [58,102]. Davies and co-workers in 2000, identifi ed a novel metabolite, Terragine from soil metagenome [90]. More recently, Diaz-Torres et al (2006) screened four metagenomic libraries made from the oral microfl ora of 20 adult human beings to identify novel tetracycline, amoxicillin and gentamycin resistant genes [65].…”