January 2015

Event Date: 
Wednesday, January 28, 2015 - 19:00 - 19:45
Institution: 
University of Sydney
Title: 

The use of genomics in diagnostic and public health microbiology

Abstract: 

Since 2004 technological advances have enabled us to sequence more nucleic acid and generate more data in a shorter amount of time. Decreases in cost per nucleotide sequenced, the initial price of sequencing machines and the complexity of library construction means that whole genome sequencing (WGS) is available in many research labs and an increasing number of public health microbiology labs. I will examine the use of WGS in public health microbiology, particularly the possibility of investigating organisms without culture, the interrogation of genomes where PCR may be unavailable, outbreak investigation, tracking resistance mutations and novel pathogen discovery.

Event Date: 
Wednesday, January 28, 2015 - 18:00 - 18:15
Institution: 
University of New South Wales
Title: 

Biomining and methanogenesis for resource extraction from asteroids

Abstract: 

As spacecraft fuel is a limited resource, creating a readily available source for hydrocarbon-based fuels in space will reduce launch cost and increase operating time of spacecraft. Biomethanation is viable for Earth-based operations, thus applications in space under controlled conditions have potential. This study proposes a sustainable environment for methanogens on Near-Earth Objects. Vacuum and desiccation effects, at 0.025% Earth atmospheric pressure, are conducted on three bacterial and three Archaea strains to test post-exposure viability. Cell degradation and colony size reduction was quantified for aerobic strains. Adverse effects were exhibited more so in gram-negative than gram-positive strains. Archaea showed limited to no cell degradation, providing evidence that vacuum effects, at these pressures, will have minor effects on in-situ biofuel operations. If successful, a sustainable and cost-effective method of metal extraction and producing methane based fuel reservoirs could revolutionise in-situ resource and fuel resupply of spacecraft, thus enhancing spacefaring capabilities.

Event Date: 
Wednesday, January 28, 2015 - 18:15 - 18:30
Institution: 
University of New South Wales
Title: 

Virus-host interactions in extreme environments, hot versus cold

Event Date: 
Wednesday, February 25, 2015 - 15:00 - 15:30
Institution: 
University of East Anglia
Title: 

Bacterial metabolism of isoprene

Abstract: 

Isoprene (methyl isobutene), is a climate-active volatile organic compound that is released into the atmosphere in similar quantities to that of methane, making it one of the most abundant trace volatiles. Large amounts of isoprene are produced by trees but also substantial amounts are released by microorganisms. The consequences on climate are complex. Isoprene can indirectly act as a global warming gas but in the marine environment it is also thought to promote aerosol formation, thus promoting cooling through increased cloud formation. We have been studying bacteria that grow on isoprene. These aerobic bacteria appear to be widespread in the terrestrial and marine environment. Rhodococcus AD45, our model organism, oxidizes isoprene using a soluble diiron centre monooxygenase which is similar to soluble methane monooxygenase. The physiology, biochemistry and molecular biology of Rhodococcus AD45 will be described, together with genome analysis, transcriptome analysis and regulatory mechanisms of isoprene degradation by bacteria. The ecology of isoprene degraders in both the terrestrial and marine environment will be described, together with DNA-Stable Isotope Probing experiments which have enabled us to identify active isoprene degraders in the environment.

Event Date: 
Wednesday, February 25, 2015 - 15:30 - 16:00
Institution: 
University of California Davis
Title: 

Stress, function and community dynamics in wastewater bioreactors

Abstract: 

Biological wastewater treatment plants receive a complex mixture of chemicals and are operated based on principles of general microbial growth kinetics. Regulated effluent criteria determine the extent of treatment required to achieve removal of chemical oxygen demand and nutrients like reduced nitrogen and phophate. Plants are, however, not designed to metabolize specific (micro)pollutants, and the factors influencing the emergence of microbial communities that are tolerant of or have evolved to metabolize and remove toxic compounds are poorly understood. Basic questions in wastewater engineering include ‘What affects the dynamics of wastewater microbial communities?’  and ‘Are communities ever stable and if so does this matter for basic processes like removal of organics and nutrients?’.  
We investigated the impact of defined and sustained chemical stress on wastewater microbial communities and their functions, using the highly toxic and recalcitrant compound 3-chloroaniline (3-CA) as model stressor. Experimental design included replicate bioreactors, sterile synthetic feed, ambient levels of 3-CA, and fixed factors like bioaugmentation and temperature. Process outcomes varied from no removal of 3-CA to complete removal within three weeks. Community changes were dramatic and nitrification was a key function affected by the stressor. Finally, microbial diversity indices based on 16S rRNA gene amplicon sequencing or T-RFLP, combined with influent nutrient concentrations, were used to predict effluent concentrations using support vector regression, a machine learning model. Sensitivity analysis of a preliminary dataset for a full-scale water reclamation plant would suggest that evenness is the most significant input variable for the prediction of soluble COD, nitrate and ammonium concentrations in the effluent. Overall, we show that both detailed analysis of taxonomy and gene expression and general indices of diversity are useful for understanding the link between stable process performance and microbial communities.

Event Date: 
Wednesday, February 25, 2015 - 16:00 - 17:00
Institution: 
Australian Museum
Title: 

Student poster competition with $500 prize money up for grabs

Abstract: 

NA

Event Date: 
Wednesday, February 25, 2015 - 17:00 - 17:30
Institution: 
University of Southern Maine
Title: 

Prochlorococcus: the “invisible forest” in the ocean’s Outback.

Abstract: 

The smallest, most abundant phototroph in the world, Prochlorococcus, dominates the base of the food web in the “Outback” of the world’s oceans, the nutrient-depleted ocean gyres. This unicellular, marine cyanobacterium, unknown only 30 years ago, is an oligotrophic specialist with a streamlined genome and reduced cellular requirement for the limited resources available in this environment. Based on physiological and molecular analyses of isolated strains from different oceans and depths, two broad groupings of Prochlorococcus were characterized: high- and low-light adapted “ecotypes”. Within these broad groupings are many subclades, some of which have been shown to dominate under certain temperature and light conditions. Through additional culture-based studies, my lab has been exploring nutrient physiology and other physiological characteristics that may contribute to the ecology and evolution of other Prochlorococcus subgroups. Some subgroups have the capacity to utilize nitrate, which was not the case for the initial isolates of Prochlorococcus, and others differ in their pigmentation. We have also found that Prochlorococcus regulates its uptake velocity and specific affinity for inorganic and organic phosphorus under P stress conditions. Examining the physiology, ecology and genomics of Prochlorococcus isolates and natural populations is providing insights into how these tiny photosynthesizing cells create a stable, yet invisible forest in the deserts of the world’s oceans.

Event Date: 
Wednesday, February 25, 2015 - 17:30 - 18:00
Institution: 
University of Melbourne
Title: 

Genomic epidemiology of antibiotic resistant bacteria

Abstract: 

Microbial populations contribute to human disease in a variety of ways, both as agents of infection and as healthy components of the microbiome. Genomic approaches can offer deep insights into this hidden microbial world, including revealing the composition of microbial communities, tracking the movement of individual organisms, and illuminating evolutionary changes. Here I will present recent work applying genomic epidemiology to investigate the emergence and spread of antibiotic resistance in a range of important pathogens, including typhoid, dysentery and the emerging hospital superbug Klebsiella.

Event Date: 
Wednesday, February 25, 2015 - 18:00 - 18:30
Institution: 
San Diego State University
Title: 

Integrating microbial community dynamics into kelp forest ecosystem models

Abstract: 

Metagenomics has enabled a greater understanding of microbial community dynamics than previously realized and now the challenge is to integrate microbial dynamics into ecological models. My lab takes an ‘omics approach mixed with classical microbiology to identify factors affecting microbial communities and how an altered microbial community will affect macro-organism health and ecosystem functioning. The key habitats are coral reefs and kelp forests. Within the kelp forest, we have started with a culturing approach that has identified novel genomes associated with the giant kelp Macrocystis pyrifera. Phenotypic assessments of these bacteria have identified increase in the microbe’s ability to tolerate copper and resist antibiotics with increasing human activities. We have tested the effects of altered microbial abundance and community composition on survival and development of M. pyrifera gametophytes. Decreasing microbial abundance enhanced M. pyrifera recruitment, increasing zoospore settlement and gametophyte development. Gametophytes reared in microbial communities sampled adjacent to the populated city showed lower survival and growth compared to gametophytes in microbial communities from a remote island. Metagenomics revealed a high abundance of phototrophic and oligotrophic microbes from the island, compared with an abundance of eutrophic microbes adjacent to the city. In addition, microbes adjacent to the city lacked genes that produce quorum signaling molecules, negatively influencing kelp spore settlement. Long term analyses of the microbial communities from the kelp forest have been initiated and we are currently investigating the microbes associated with the water column and kelp surface at two distinct depth. First, at 0.5 m depth where the water is warmer, highly oxygenated and receiving large amounts of carbon from photosynthesis and second, at 15 m depth where the water is under seasonal thermocline, colder, lower in oxygen, and can potentially be exposed to high partial pressure of carbon dioxide. Monthly sampling has revealed microbial number is lower at depth and pCO2 is higher. Metagenomic analysis of these samples is under way. Kelp feeds the ecosystem through degradation and we are currently investigating the effects of microbes on kelp degradation and subsequent nutritional value. We have shown altered microbial communities are detrimental to kelp recruitment and are identifying way of adding these data to ecosystem models.

Event Date: 
Wednesday, February 25, 2015 - 19:30 - 22:30
Institution: 
Australian Museum
Title: 

Two course meal in the skeleton room with live music

Abstract: 

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