-bacter

Event Date: 
Wednesday, September 24, 2014 - 18:00 - 18:15
Institution: 
University of Sydney
Title: 

Microbiota characterisation in the Tasmanian devil

Abstract: 

The Tasmanian devil (Sarcophilus harrisii), the world’s largest remaining carnivorous marsupial, faces extinction due to the spread of a contagious cancer called Devil Facial Tumour Disease (DFTD). The lack of a description of the bacterial community composition in the species represents a major gap in our knowledge of Tasmanian devil biology. In this study we characterised 12 microbiomes from four body sites, including mouth, gut, skin and pouch, in five Tasmanian devils via PCR amplification of 16S rRNA gene V1-V3 regions followed by 454 sequencing.  A total of 249,224 reads with an average sequence length of 489 bp were obtained after length and quality filtering. The reads further clustered into 14533 operational taxonomic units (OTUs; sequence identity cutoff of >97%) that were classified to 24 phyla spanning 275 families. Higher levels of bacterial species richness were observed in the pouch and skin than in the mouth and gut. The pouch and skin showed similar microflora compositions, which may vary between animals, possibly due to different environments. Distinct from the previously reported koala gut microbiota [1], which is dominated by Bacteroidetes and Firmicutes, the devil gut microbiota was found to be dominated by Fusobacteria, Firmicutes and Proteobacteria, comprising up to 73.7-94.3% of the community. This study has greatly improved our understanding of the microbial communities in the Tasmanian devil, which will significantly contribute to the effort to conserve the species.

JAMS REPORT
Tom Jeffries
 
January JAMS got the new year off to a good start with a solid turnout and some stimulating talks. First up was Olivier Laczka who took us in to the technical realm of biosensors. Olivier’s work has focused on developing cost-effective tools for the rapid identification of micro-organisms relevant to industry and has led to several Patents.

Event Date: 
Wednesday, January 30, 2013 - 18:15 - 18:30
Institution: 
University of Western Sydney
Title: 

Changes in soil microbial community precede changes in plant community along a chronosequence

Abstract: 

Shrubs in semiarid ecosystems facilitate the establishment of other plant species under their canopies and promote changes in these understory plant communities as they grow. To better understand whether plant community dynamics are linked to changes in soil microbes, we characterized soil microbial communities in gaps (interspaces) and under Retama sphaerocarpa shrubs of three different size/age classes. Different methodological approaches including pyrosequencing of 16S rDNA, phospholipid-fatty acid (PLFA) analysis and microbial activity indicators were combined to characterize both the structure and function of microbial communities along the chronosequence. Small shrubs induced an increase in soil bacterial and fungal biomass, a stimulation of microbial activity and changes in the relative abundance of several bacterial groups, preceding aboveground increase in plant richness and biomass. Shrubs promoted a significant increase of Bacteroidetes, Betaproteobacteria and Gammaproteobacteria abundance in detriment of Actinobacteria and Firmicutes without changes in overall bacterial diversity. Some changes in the microbial community increased with shrub age while other did not, being microbial communities in gaps and under the canopy of large shrubs the most differentiated. We argue that the observed changes in composition and function of soil microbial communities may promote the increase in plant growth and understory species richness along the chronosequence. This emphasizes the importance of plant-soil interactions on defining the structure and composition of both plant and soil microbial communities and their impact on ecosystem functioning.

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