Technology

Event Date: 
Wednesday, October 29, 2014 - 18:15 - 18:30
Institution: 
UTS
Title: 

Stigmergic social behaviours facilitate the active expansion of Pseudomonas aeruginosa interstitial biofilms.

Abstract: 

Erin S. Gloag1, Awais Javed2, Huabin Wang3, Michelle L. Gee3, Scott A. Wade2, Lynne Turnbull1, Cynthia B. Whitchurch1*
1 The ithree institute, University of Technology Sydney, Ultimo, NSW, 2007, Australia.
2 Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, 3122, Australia
3 School of Chemistry, University of Melbourne, Parkville, VIC, 3010, Australia.
 
Biofilms are often found associated with infections of implantable medical devices; accounting for approximately half of all nosocomial infections. Biofilms are often thought of as sessile surface-attached communities that are embedded in a protective slimy matrix. However, many bacterial pathogens also have the capacity to actively expand their biofilm communities via complex multi-cellular behaviours. We have observed that when P. aeruginosa is cultured at the interstitial surface between a coverslip and solidified nutrient media the resulting biofilm actively expands via twitching motility and is characterised by the formation of an extensive pattern of interconnected trails.
We set out to identify the factors governing pattern formation and coordinated movement during P. aeruginosa interstitial biofilm expansion. Our observations have revealed that during biofilm migration the cells at the advancing edge create furrows as they migrate across the semi-solid media The following cells are preferentially confined to these furrows, resulting in the emergence of an interconnected furrow network and the subsequent extensive large scale-patterning characteristic of these biofilms.
Stigmergy is a concept which describes self-organisation processes observed in higher organisms and abiotic systems through indirect communication via persistent cues in the environment left by individuals that influence the behavior of other individuals of the group at a later point in time. Our observations indicate that self-organised pattern formation in P. aeruginosa interstitial biofilms is also a stigmergic phenomenon. To our knowledge this is the first time that stigmergy has been identified as a mechanism of self-organisation of bacterial biofilms and propose that the concept of stigmergy can be included in the repertoire of systems used by bacteria to co-ordinate complex multicellular behaviours. We are currently exploring the development of novel antimicrobial strategies aimed at controlling and inhibiting biofilm expansion in medical settings via exploiting our new understanding of biofilm expansion.

Event Date: 
Wednesday, September 24, 2014 - 19:00 - 19:15
Institution: 
CSIRO
Title: 

Animating the Gut Microbiome

Abstract: 

Animation can be a powerful way to inspire and educate people with science. Creating biomedical animations which depict advanced scientific concepts in a clear way requires 2 main considerations, 1) rigorous investigation of the underlying science, and 2) careful development of the story to express the ideas in a meaningful way.

In this talk Christopher Hammang will present his first biomedical animation “The Hungry Microbiome”. He will explore the challenges involved in animating the human gut microbiome and the unique insight gained from creating an animation about resistant starch. The talk will also explore the workflow and technology which can be used to create these biomedical animations, as well as a brief review of the science underlying resistant starch research.

 

Event Date: 
Wednesday, September 24, 2014 - 18:15 - 18:30
Institution: 
University of Sydney
Title: 

Cathelicidins in the Tasmanian devil (Sarcophilus harrisii)

Abstract: 

Antimicrobial resistance is increasing, posing a threat to human and animal health. A lack of new antibiotics means alternatives such as antimicrobial peptides are urgently required. Antimicrobial peptides are a primitive component of the innate immune system. Cathelicidins are a predominant family within mammals, contributing to host immunity through antimicrobial and immunomodulatory functions. They have been studied extensively in eutherian mammals but marsupials are relatively unexplored. Marsupials give birth to altricial young which are immunologically naïve. During development the young are protected from infection by mechanisms such as cathelicidins within the pouch. This unique reproductive physiology has encouraged lineage specific expansion of the cathelicidin gene family within marsupials, resulting in numerous diverse peptides.
 
The Tasmanian devil (Sarcophilus harrisii) is the largest remaining carnivorous marsupial and is currently under threat from a contagious cancer, devil facial tumour disease (DFTD). Human and bovine cathelicidins exhibit anti-tumour activity against a number of cancers. Furthermore, studies in the tammar wallaby have revealed the potency of marsupial cathelicidins against multi-drug resistant bacteria. As such, release of the Tasmanian devil genome in 2012 provides new avenues in the search for cathelicidins with the therapeutic potential to treat DFTD and resistant pathogens.
 
We identified 7 cathelicidins in the Tasmanian devil genome which were highly variable and distantly related to eutherian cathelicidins. Six Tasmanian devil cathelicidins have been synthesised and will be tested against a range of bacteria and fungi. Preliminary antifungal testing of two cathelicidins revealed that one peptide was more effective at killing Candida krusei, Candida parapsilosisCryptococcus gattii and Cryptococcus neoformans than the antifungal drug fluconazole. Cytotoxic and haemolytic activity of all six cathelicidins has also been determined. Four cathelicidins did not kill human lung epithelial cells or red blood cells, and only two showed moderate cytotoxic and haemolytic activity. This study highlights the potential for marsupials such as the Tasmanian devil to provide new drugs to treat human and animal disease.

Event Date: 
Wednesday, October 30, 2013 - 18:00 - 18:15
Institution: 
UNSW
Title: 

NO signals for dispersing biofilms in clinical and industrial applications

Abstract: 

A story from science bench to bedside, or at least towards it What started as purely academic studies of the life cycle of bacterial biofilms, addressing the regulation of cell death events during late developmental stages, led to the discovery of a role for nitric oxide (NO) as a key regulator of biofilm dispersal. NO, which is a simple gas and universal biological signal, was found to be produced endogenously in mature biofilms, and trigger a signaling pathway involving the secondary messenger cyclic di-GMP, which in turn activates cellular effectors resulting in dispersal. Add-back of low levels (picomolar to nanomolar range) of NO was able to induce dispersal across various single species and mixed species biofilms. While the biofilm mode of growth confers a high level of resistance to control measures including antibiotics, exposure to NO greatly increases the efficacy of a range of antimicrobial treatments. Therefore the use of low, non-toxic concentrations of NO represents a promising strategy for the management of biofilms in medical and industrial contexts. Several NO-based technologies have been developed to control bacterial biofilms, including: (i) NO-generating compounds with short or long half-lives and safe or inert residues, (ii) novel materials and surface coatings which catalytically produce NO in situ, and (iii) novel compounds for the targeted delivery of NO to infectious biofilms during systemic treatments.

Event Date: 
Wednesday, June 26, 2013 - 18:15 - 18:30
Institution: 
UWS
Title: 

How to dismantle a “Trichy” parasite: Deciphering the role Tritrichomonas foetus membrane and secreted proteins play at the host-parasite interface.

Abstract: 

 
Tritrichomonas foetus is a potent veterinary pathogen, causing bovine and feline trichomoniasis. While T. foetus is well know as a venereal pathogen of cattle, it has only recently been discovered as a pathogen of cats in which it causes chronic diarrhea. T. foetus imposes significant economic losses on the beef and dairy industries worldwide. Nonetheless, despite its prevalence, T. foetus is neglected relative to other parasites of veterinary concern. There is currently no effective treatment or vaccine and prevention of infection in cattle and relies on culling infected animals. Chemotherapy in cats is limited and, depending on the country, is either not recommended or prohibited due to limited efficacy and toxicity. These extracellular parasites secrete a range of molecules that aid in tissue destruction, nutrient acquisition and immune-evasion. Proteins expressed at the host-parasite interface (i.e. secreted and membrane proteins) are critical to promoting parasite development and survival. Our central hypothesis is that these key molecules, which mediate infections caused by T. foetus, present a target for the rational design of future treatment and control strategies.

Event Date: 
Wednesday, April 24, 2013 - 19:15 - 20:00
Institution: 
University of Technology Sydney
Title: 

Observing the developing infant gut microbiome with time-series metagenomics.

Abstract: 

The human body plays host to a complex microbial ecosystem, the
development of which begins around the time of birth. Routine monitoring
of the development of microbial ecosystems in newborns (or other
environments) using metagenomic methods is currently extremely
challenging and expensive. I will describe some recent technological
advances that could enable routine sequencing and computational analysis
of hundreds of metagenomes, and demonstrate their application on samples
taken from a developing infant gut microbiome. In this study forty-five
samples were subjected to transposon-catalyzed Illumina library prep and
metagenomic sequencing on a HiSeq 2000 instrument. The resulting data
was subjected to analysis of microbial community structure using a new
approach called phylogenetic Edge Principal Component Analysis (Edge
PCA) that can identify which lineages in a phylogeny explain the
greatest degree of variation among the samples. We also investigate the
population genomics of Bacteroides thetaiotaomicron, one of the dominant
members of the gut microbial community.

Event Date: 
Wednesday, January 30, 2013 - 18:00 - 18:15
Institution: 
University Technology Sydney
Title: 

Development of an electrochemical biosensor for bacteria detection coupling immuno-capture with magnetic particles and amperometry at flow-channel microband electrodes.

Abstract: 

 
Current technology is insufficient for rapid on-site identification of the causative agents for waterborne diseases and existing time-consuming detection results in delayed management decisions. Fast, reliable and low-cost methods for the screening of pathogens are paramount in fields such as the environment, food industry, healthcare and defense. With the constant progress of scientific knowledge, a fast diversification of detection techniques is occurring, brought about by the appearance of imaginative new concepts within the scientific community. Biosensors are a perfect example of the combination of multidisciplinary knowledge. They encompass many fundamental, technological and scientific advances in biology, chemistry and physics.
Here, we describe a recently developed electrochemical biosensor for the detection of bacteria cells in aqueous samples. The technology used for this detection combines immuno-magnetic capture and amperometric detection in a one-step sandwich format, and in a microfluidic environment. The whole assay could be completed in 1 h and the experiments performed with Escherichia coli evidenced a linear response for concentrations ranging 102–108 cell ml−1.

 
Prepared by Valentina Wong (UNSW PhD student)
On a cold Tuesday night, Adrian Low from University of New South Wales warmed the JAMS audience with his passion on bioremediation of organochlorine contaminated groundwater. Adrian described the discovery of Australia’s first 1,2-dichloroethane (DCA) degrading consortium, AusDCA. His work in the field demonstrated the efficacy and sustainability of using organochlorine respiring bacteria to remediate organochlorine contaminants in situ. He plans to isolate the bacterial species responsible for performing this unique task.

Syndicate content