Professor Staffan Kjelleberg from the School of Biotechnology and Biomolecular Sciences (BABS).

Staffan received his PhD from the University of Gotenburg, Sweden in 1981, and joined the staff of the then School of Microbiology and Immunology in 1993 as Professor of Microbiology. He has a long standing interest in various aspect of environmental microbiology.

Professor Peter Steinberg from the School of Biological, Earth and Environmental Sciences (BEES).

Peter received his PhD from the University of California in 1984, and was appointed at UNSW as a Lecturer in 1991 in the then School of Biological Science. His focus is marine chemical ecology, with particular interests in interactions at surfaces and prokaryote/ eukaryote interactions.

Suhelen Egan

While scientists continue to discover novel metabolites from the marine environment much of this work is hindered by the need for high throughput screening (HTS) which is costly and time consuming. To reduce the need for HTS we have used our understanding of specific bacterial-host associations for the targeted isolation of novel compounds.

The project involves:
1) A culturing approach which involves the targeted isolation of marine microbes from sites where bacteria are potentially involved in a protective relationship with higher organisms such as seaweeds and invertebrates. As much as 15 % of our isolates were found to produce relevant compounds; and
2) A metagenomic approach in which we apply whole environmental genomic (metagenomic) technology to the discovery of bioactive compounds from marine surface microbial communities. In collaboration with the J. Craig Venter Institute (Rockville, USA), we will directly sequence selected microbial communities. This will allow us to link data mining and functional screening (of large insert clone libraries) to novel metabolites and their biosynthetic pathways.

In addition to the search for novel bioactives we have an ongoing research program that focuses on the model antifouling bacterium Pseudoalteromonas tunicata. This organism has been isolated in association with marine sessile eukaryotes (algae and invertebrates) and is known to produce a battery of compounds with activity against a variety of common marine fouling organisms (bacteria, fungi, protozoa, algae and invertebrates). Specifically we are interested in elucidating the chemical structure of these compounds and gaining an understanding of the regulation and mode of action of each of these metabolites. Within this program we are using a variety of molecular biology techniques including the analysis of the whole genome sequence of P. tunicata.

Paul Gribben

Dr Gribben is investigating both positive (inducing) and negative (inhibiting) chemical cues from algae that may regulate the fouling community on marine algae. In particular, he is investigating whether chemical cues from algae are responsible for the large numbers of the juvenile green-shelled mussel, Perna canaliculus, found on certain species of beach-cast algae around the New Zealand shoreline. Mussels on these algae are collected as seed stock, and support New Zealand’s mussel culture industry. Thus the whole industry is prone to the vagaries of natural processes to deliver the seed source. In a project jointly funded by the National Institute for Water Atmospheric Research (NIWA) in New Zealand, Paul is investigating whether potential chemical cues from these algae can be exploited to enhance the supply of seed to the industry. Paul is also investigating whether habitat forming invasive species interfere with the settlement and recruitment of native invertebrates and algae, and the implications that poor habitat choice of native organisms, in the presence of invasive species, has for the maintenance of native populations.

Carola Holmström

Dr Holmström directs research on marine prokaryote/eukaryote interactions and bacterial colonisation of living surfaces in the marine environment. Current research on microbial colonisation focuses on two model systems: Delisea pulchra and Ulva australis. We have generated 16S rDNA clone libraries for both bacterial communities on these organisms and assessed variation in bacterial composition over time through 16S rDNA based denaturing gradient gel electrophoresis. A Fluorescence in situ Hybridisation (FISH) technique for detecting bacteria on seaweed surfaces was developed in 2004. This technique, CARD-FISH, was successfully applied to several marine algae to directly assess the distinction of bacteria belonging to phylogenetic subgroups and genera. These studies also revealed that the bacterial community differs in structure and comparison between the tip and base of the plants, ranging from diverse cell morphologies and fully developed biofouling communities on the base while the tip parts contain less bacterial biomass and structures such as biofilm microcolonies.

Furanones from D. pulchra are natural antagonists of the acylated homoserine lactone (AHL) and AI-2 bacterial signalling systems. These systems control key aspects of biofilm formation and virulence expression in many bacteria. The development of signalling antagonists for use as novel treatments to prevent biofilm formation and pathogenesis is of particular interest to the CMBB. Carola has long standing experience in biofilm and marine biofouling formation and is also engaged in the biofouling project undertaken for the EBCRC.

Diane McDougald

Dr McDougald is investigating the role of bacterial communication systems in the regulation of virulence factor expression, biofilm formation and responses to environmental stresses, in pathogenic Vibrio species.
Diane directs research on environmental adaptation and survival of marine pathogenic Vibrio species and the prevention of virulence of these bacteria. In many bacteria, the regulation of phenotypic traits is controlled by signalling pathways where extracellular factors are used to coordinate the expression of traits at the population level. One such signalling pathway is the AI-2 signalling pathway that has been identified in a wide range of bacteria. We have shown that this signalling pathway is important for the regulation of several traits that are needed for bacterial cells to survive stresses encountered in the marine environment. Furthermore, we are testing novel antagonists of these communication systems for their potential use as antimicrobials.
It is known that Vibrio cholerae can survive in copepods in the marine environment and that Vibrio vulnificus is routinely found in shellfish and sediments. Most bacteria in the marine environment form biofilms as a mechanism to obtain nutrients. It was shown that the signalling system is important for biofilm formation and dispersal and that this system regulates the production of exoproducts that prevent protozoan grazing.

Mike Manefield

Dr Manefield has a broad range of scientific interests unified by the phenomenon whereby biological entities move inexorably towards higher degrees of complexity and cooperation. He channels this interest into the development of molecular methods, the testing of ecological theory and the application of his findings in the field of microbial ecology. Dr Manefield runs three research projects. The first involves the development of bioremediation solutions for contaminated sites in the Sydney region funded by the Cooperative Research Centre for Environmental Biotechnology. The second involves developing cultures for bioaugmentation of a chlorinated hydrocarbon contaminated aquifer in the Sydney region funded by the chemical company Orica Australia. The third is an experimental evolution approach testing models of community level selection funded by the Australian Research Council.

Beyond his work in bioremediation and experimental evolution, Dr Manefield participates in research programs on microbial food webs, bacterial intercellular signalling, microbe mediated methane consumption and the development of novel methods to characterise microbial communities. Many of these projects exploit activated sludge in wastewater treatment as an applied and experimental context to further our understanding of the microbial world.

Scott Rice

Dr Rice examines how bacteria communicate with other members of the population, through a process known as quorum sensing, and how they use such chemical cues to control the expression of behaviours important for survival in the environment (eg. biofilm formation and virulence factor expression). Current research is also examining how the biofilm encourages the formation of morphological variants with different properties (eg. altered biofilm formation and virulence factor production) and the role played by the biofilm in mediating resistance to grazing by protozoa. By understanding how bacteria regulate biofilm formation and virulence factor expression and by knowing what genes are important for these processes, it should be possible to target those systems to reduce their impact where biofilms are detrimental or to encourage biofilm formation where they play important biological roles (eg. waste water systems, granule or floc formation). One area of particular interest is the development of compounds that occur naturally in the environment that act as quorum sensing antagonists for use as novel treatments to prevent biofilm formation and pathogenesis of bacteria. These projects involve several model bacteria, Pseudomonas aeruginosa, Serratia marcescens, and Vibrio cholerae, as well as mixed species natural communities and the research outcomes are relevant to areas from medical microbiology to environmental microbial ecology.

David Schleheck

David’s PhD research has focused on the microbiology, biochemistry, and analytical chemistry of environmental biodegradation processes. Dr Schleheck joined the CMBB as UNSW Vice Chancellor Postdoctoral Fellow in 2005 to learn about bacterial biofilms. David directs two research projects at the CMBB.
1) Surfactant-degrading biofilm consortia. A large bacterial consortium needed to completely degrade linear alkylbenzenesulfonate (LAS), the major laundry surfactant in world-wide use. A representative model system for this cooperative environmental biodegradation process, a defined three-member consortium, is available for laboratory studies. The organisms grow predominantly in biofilms or in flocs dependent on the presence of surfactant as stress agent. David explores the role of multi-species biofilm formation in surfactant resistance and surfactant biodegradation, and aims to follow the community interactions in the three-species consortium. The three species, Parvibaculum lavamentivorans, Comamonas testosteroni, and Delftia acidovorans, have been selected for genome sequencing by the U.S. Department of Energy as part of the Microbial Genomes Program 2006. The analysis of the consortia’s genome is planned in a linkage of research groups at UNSW (S. Kjelleberg, R. Cavicchioli), University of Konstanz (A.M. Cook), University of Lausanne (J.R. van der Meer), Exeter University (H. Lappin-Scott), and Swiss Federal Institute of Aquatic Science and Technology (H.P. Kohler).
2) Dispersal of cells from biofilms. The biofilm-mode of growth of bacteria, especially the formation of biofilms and their persistence, has been a major focus of microbial research in recent years. The programmed detachment of planktonic cells from biofilms remains less well defined. Using Pseudomonas aeruginosa as a model, David explores factors which determine the dispersal of planktonic cells from biofilms."

Torsten Thomas

Dr. Thomas’ research aims to integrate genomics into the field of microbial ecology and therefore to relate genome composition with environmental function. His main activities cover:
1. Whole-environment genomics (metagenomics):
Microbial diversity and function for most environments still remains poorly defined. Application of genomic technology to environmental systems provides an avenue to study the entire genetic composition of even the most complex microbial systems. This approach is being applied to describe uncultured microbes and novel bioactivities in marine systems, including communities associated with marine, living surface.
2. Comparative genomics:
The genome of a particular organism should reflect its ecological function and its habitat’s properties. In collaboration with major genome centres in the US, several genomes of important, environmental microorganisms have been sequenced and are being analysed. These comparative analyses are focussed to provide fundamental and comprehensive information on marine surface-associated and planktonic life using Pseudoalteromonas and Roseobacter species as model organisms.
3. Population microheterogeneity:
Microbial genomes exhibit a high degree of plasticity (or variability) and any given microbial population (defined as a collection of closely-related individuals) is far more heterogenous in its genetic composition than previously assumed. High-throughput genome sequencing of entire populations and comparative analysis of closely-related isolates allows for a comprehensive observation of genome evolution on a molecular level. This approach is being employed to the model organism Pseudomonas aeruginosa to understand its adaptation and evolution to conditions of environmental and medical relevance.

Dr Yee comes from a polymer chemistry background and is keenly interested in applying this knowledge to a number of projects within the CMBB.

1) Encapsulation and immobilisation of bacteria and cells.
Emerging as a very broad field that includes the use of bacterial fermentation reactors for the production of enzymes, through to encapsulation of cells for the in vivo treatment of diabetes patients. Dr Yee is pursuing the marine biofouling application of such technology with the ultimate goal of producing a ‘living paint’. Bacteria capable of producing antifouling compounds that prevent unwanted settlement in a marine environment will be kept alive in a coating to provide natural protection against common fouling organisms such as algae and barnacles.

2) Polymers assisting bioremediation of soil.
Toxic laden soils exist throughout the global environment. Bacterial remediation of soil containing harmful organic compounds has been firmly established as a means of treating such toxic sites. However in regions where water deficiencies occur, bacterial activity is limited. Polymers can provide a means of long term water storage at depth in the soil, and provide ideal living conditions for the bacteria to remediate the organic toxins.