Streptomyces

Event Date: 
Wednesday, May 28, 2014 - 18:00 - 18:15
Institution: 
UNSW
Title: 

Regulation of Secondary Metabolites Production in Streptomyces coelicolor

Abstract: 

Streptomyces coelicolor produces a wide array of secondary metabolites that include antibiotics, actinorhodin (Act) and undecylprodigiosin (Red). When analysed for the growth of S. coelicolor on blood containing medium, we found that a functional haemolysin was critical for its growth. Gene knock-out and complementation analysis revealed the expression haemolysin was critical for growth, sporulation and antibiotics production. Total proteome comparison of wild-type and haemolysin deletion mutant indicated a wide range of carbon metabolizing enzymes to be down-regulated. Further analysis of selected targets that could encode phosphomannose isomerase and alpha-mannosidase revealed these sugar processing enzymes to play a critical role on growth, sporulation and antibiotics production in S. coelicolor.

Event Date: 
Wednesday, April 30, 2014 - 18:15 - 18:30
Institution: 
CSIRO
Title: 

Genetic diversity of Group I Clostridium botulinum and Clostridium sporogenes

Abstract: 

Whilst classified as a single bacterial species, Clostridium botulinum comprises a phylogenetically and physiologically diverse collection of organisms. Members of this species are linked together based solely on the production of botulinum neurotoxin (BoNT); amongst most lethal natural toxin produced. Isolates that do not produce BoNT are taxonomically considered a separate species, such as Clostridium sporogenes. Given the species delineation is based solely on an unstable phenetic trait presents increasing challenges in a post-genomic era, particularly with increasing evidence pointing towards the lateral acquisition of BoNT production in many strains. Here, the pan-genome of Group I C. botulinum and C. sporogenes is presented, describing the genetic diversity of these species, highlighting the incongruent taxonomy of these organisms and presenting insights into the acquisition of BoNT within this group.

Event Date: 
Wednesday, June 29, 2011 - 18:15 - 18:30
Institution: 
Scripps Inst. of Oceanography, UC San Diego
Title: 

Regulation and heterologous expression of bioactive natural products from the filamentous marine cyanobacterium Lyngbya majuscula.

Abstract: 

The marine cyanobacterium Lyngbya majuscula is well recognized as a rich source of bioactive secondary metabolites that are valued as both drug candidates and resources in biotechnological applications. Although considerable advances have been made in understanding the gene clusters involved in molecule assemblies, the potential of many Lyngbya metabolites has yet to be harnessed because of low yields from field collections and slow growth in laboratory cultures. Two possible routes to improving Lyngbya natural product yields could be through discovery and manipulation of regulatory mechanisms associated with Lyngbya biosynthetic pathways, and establishment of a reliable heterologous expression platform for Lyngbya metabolites. In previous efforts studying the regulation of natural products from Lyngbya, we isolated light related transcription factor proteins that may be used to regulate production of the jamaicamides, neurotoxic compounds from a Jamaican Lyngbya strain. We have developed an approach to monitor rates of jamaicamide A and B biosynthesis in vivo using a combination of mass spectrometry and stable isotope feeding, and found different rates of biosynthesis between these two molecules in light and dark conditions. This approach has been used to measure the effects of a variety of culture conditions on natural product turnover in cyanobacteria. Current efforts towards heterologous pathway expression are focused on the dermatotoxic lyngbyatoxins from a Hawaiian Lyngbya collection. Functional Lyngbya recombinant protein expression has been achieved using the model actinomycete Streptomyces coelicolor, and we are now attempting to determine if Streptomyces is capable of expressing the entire lyngbyatoxin pathway.

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