Search Marsden awards 2008–2017

Recipient(s): Dr NOV Plank | PI | Victoria University of Wellington

Public Summary: This project will investigate how to exploit nanowires for exceptionally sensitive lab-on-a-chip electronic biosensors. With electronic current flow constrained to nanometer sized channels, biosensors can detect very weak interactions between biological molecules and the surface of the nanowire. Sensitivity in the parts-per-billion range can be easily achieved. However, sensitivity is a double-edged sword; the electronic properties of nanowire devices are so sensitive to the environment that some electronic signals may have a variety of causes. The signals that a biosensor is designed to detect can easily be overwhelmed by the effects of other molecules on various parts of the nanowire device.

This project aims to confront this lack of ‘selectivity’ in nanowire sensors by fabricating a series of devices designed to isolate the effects of the various molecules to which the device is exposed. Starting with single-nanowire devices in which only specific regions are exposed to specific parts of the environment, a selectivity profile will be built. The relative influence of each effect will then be elucidated upon scaling up to multi-nanowire devices. The outcome of these experiments will provide a roadmap for development of nanowire biosensor devices that exhibit both exceptional sensitivity and selectivity.

Recipient(s): Assoc Prof J Briskie | PI | University of Canterbury
Prof B Kempenaers | AI | Max Planck Institute for Ornithology

Public Summary: Some New Zealand birds have strong odours. Even to our relatively insensitive noses, kiwi smell like ammonia while the odour of kakapo has been likened to a dusty violin case! Strong odours are unusual in birds, but common in mammals, which use odours for communication and locating food. Preliminary work has revealed that strong odours may be widespread among New Zealand birds, and that these odours arise from the preen waxes produced in the uropygial gland. Preen waxes function to maintain feathers, but may also attract predators that use olfaction to locate prey. We will test if differences in the composition of preen waxes between island and continental birds are the result of their differing evolutionary histories with predatory mammals. The South Pacific area, including New Zealand, provides an ideal system for studying odours and predation risk as we can compare preen wax composition across a number of island birds that evolved without mammalian predators and their close phylogenetic relatives that co-evolved with predators in Australia. We will then test whether these differences in odours now put island birds at greater risk from introduced mammalian predators. This study will not only increase our understanding of the evolution of odours in birds, but for the first time, determine whether odours are playing a previously unrecognised role in the decline of island birds.

Recipient(s): Assoc Prof M Alkaisi | PI | University of Canterbury
Assoc Prof JJ Evans | PI | University of Otago

Public Summary: Dialogue between engineers and biologists have increased because mechanical forces from the microenvironment are central to functioning of biological cells. Thus cells exert forces on neighbours as they grow. In the cases where tissue repair or regeneration is attempted in the event of accident or disease a substrate may be chemically constructed with nanoscale details that are vital to the new cells’ behaviour.
Nanostructured materials which mimic the nanometre topography of the native tissue showed improved biological responses and result in better integration in medical implants.
With the increasing developments of BioMEMs and medical devices, understanding of cell interactions with surfaces and materials is becoming very important. It has also been suggested that some cancers are caused by inappropriate mechanical force balances which activate deleterious growth and proliferation pathways. Hence an engineering approach may produce biomaterials and nanostructures that have potential to reverse cancer advancement.
We have a unique capability of forming replicas of cells with nanoscale fidelity that can be scaled onto 3D scaffolds on biocompatible materials. We will be investigating for the first time the responses of cells interacting with patterns that resemble themselves. These methodologies could lead to new implant coatings that are biocompatible, bioactive and organ specific.

Recipient(s): Dr CL Jacobson | PI | The University of Queensland
Prof F Berkes | AI | University of Manitoba
Prof H Moller | AI | University of Otago
Prof HA Ross | AI | The University of Queensland

Public Summary: Co-management is a shared approach to environmental management between indigenous and non-indigenous peoples. A component of co-management is the weaving together of different knowledges – science, indigenous and local. However, these knowledges are paradigmatically different and therefore difficult to integrate. Knowledge issues are acknowledged as one of the most significant challenges for co-management. Governance arrangements are considered key to understanding improved methods for managing knowledge aspirations, although there is little study of exactly how they affect knowledge integration. We aim to understand aspirations related to different place-based knowledge systems, and the implications of different governance arrangements on their expression, integration and application. Understanding the linkages between institutional arrangement and the integration of different knowledges is crucial to improving co-management in practice, and requires comparative analysis. We will investigate knowledge aspirations, the effect of governance arrangements on their expression, and the ways in which they can be adapted in order to improve co-management practice, using a diversity of case studies with different governance and institutional arrangements from both New Zealand and Australia. By contrasting diverse experiences, we will be able to identify how co-management could be strengthened, and, provide pathways forward for government in a post-colonial era.

Recipient(s): Dr DJ Fleetwood | PI | AgResearch
Prof RC Gardner | AI | The University of Auckland

Public Summary: Few, if any, plants live alone. From forest trees to pasture grasses plants harbour fungi called endophytes in their leaves in a mutually beneficial “symbiotic” relationship where the plant provides nutrition to the fungi, which in return produce chemicals that protect the plant from an array of stresses. We know why plants harbour endophytes, but little is known about how these relationships are formed. Plants have sophisticated defence mechanisms to ward off pathogens and somehow symbiotic fungi must evade these defences and signal that they are not pathogens.

We propose to use the latest molecular approaches to dissect why a genetically-altered endophyte we have identified no longer forms a symbiotic relationship with its host plant. Results from this research will elucidate how endophytes avoid host defences and will advance our fundamental knowledge about how these important relationships between plants and fungi really work.

Recipient(s): Dr F Caratori Tontini | PI | GNS Science
Dr L Cocchi | AI | Istituto Nazionale di Geofisica e Vulcanologia
Dr C de Ronde | AI | GNS Science
Dr M Leybourne | AI | GNS Science

Public Summary: A long chain of mainly submarine volcanoes marks the Kermadec arc northeast of New Zealand, a consequence of collision between the Pacific and Australian plates. Terrestrial volcanoes commonly undergo sector collapse from weakening of the summit by geothermal alteration. However, the causes and extent of sector collapse on arc and backarc submarine volcanoes and potential to generate large tsunami events is largely unknown. We will investigate this phenomenon using gravity and magnetic geophysical techniques, combined with novel new algorithms that we are developing to accurately locate and map zones of hydrothermal alteration and rock mass weakening on southern Kermadec arc volcanoes. We will generate a model of edifice collapse using new high-resolution data from cruises in 2010 and 2011. Our geophysical models will be further refined using density and magnetisation analyses on rock samples collected from these volcanoes. These results, combined with morphological data of edifice shape and crustal structure, will allow us to determine the zone on southern Kermadec volcanoes that are most prone to sector collapse, thereby creating a tsunami risk. We will generate a tsunami risk model that will be applicable to all submarine volcanoes along the Pacific Ring of Fire.

Recipient(s): Dr RCJ Dobson | PI | University of Canterbury
Dr TF Cooper | AI | University of Houston

Public Summary: Adaptation is the process by which a population moves towards a phenotype that represents a better fit to the environment. We know a lot about the consequences of adaptation, but little of the underlying molecular causes of adaptation; that is, how do mutations in a gene act to change an organism’s phenotype.

In a laboratory experiment, 12 replicate bacterial populations were evolved from a common ancestor in a glucose-limiting environment. Over time, the fitness of each population increased and, interestingly, mutations concentrated in relatively few genes. For the gene that encodes pyruvate kinase, an enzyme central to the regulation of energy metabolism, mutations occurred independently in all 12 populations—a signature that they are likely to be adaptive.

Why is this enzyme a focal point for adaptive mutations? This question demands a molecular ‘picture’ of the adapted pyruvate kinase enzymes, linked with fitness and metabolic information. To achieve this, an interdisciplinary team will integrate biochemical, protein structural, metabolic and evolutionary experiments to assess the effect of the adaptive mutations at these levels. Empirical data addressing why some mutations are adaptive (but most are not) will have major implications for our ability to predict and understand the outcome of evolution.

Recipient(s): Prof G Whittle | PI | Victoria University of Wellington

Public Summary: The discrete world is fundamentally different from the continuous. Classical mathematics has primarily focussed on continuous structures, but computers are discrete machines, DNA is discrete, and the internet gives us information that is digital, that is, gives us discrete information. Matroids are mathematical structures that describe the geometry that underlies discrete objects. This geometry is intrinsically different from the world described by classical mathematics.

One way to obtain a matroid is from a structure called a finite field. Matroids obtained from the 2-element field are particularly natural to your computer. But matroids obtained from other finite fields are also of great interest.

This project seeks to resolve two fundamental conjectures on matroids. We aim to prove that matroids obtained from a finite field are well-quasi-ordered. In other words, we aim to prove that, in any infinite list of such matroids, there is one that is a substructure of another. We also aim to prove Rota's Conjecture that, for any finite field, there is a finite set of matroids that can be used to determine if a matroid can be obtained from that field. These two conjectures are widely regarded as the most famous in matroid theory.

Recipient(s): Dr L Pang | PI | Institute of Environmental Science and Research
Dr RD Tilley | AI | Victoria University of Wellington
Dr A Varsani | AI | University of Canterbury

Public Summary: Consuming pathogen-contaminated groundwater causes human diseases, but very little is known about the behaviour of pathogens in groundwater. Tools to investigate pathogens in groundwater are limited, and pathogens cannot be deliberately introduced in field experiments. Our preliminary study suggests that we can overcome these barriers by designing and making pathogen surrogates for laboratory and field studies, using harmless natural materials. In this study we will mimic rotavirus transport in groundwater by developing surface charge-modified, DNA-labelled and protein-coated silica nanobeads that mirror the size and surface charge of rotavirus – properties that dictate virus retention and transport in aquifers. The retention and transport behaviours of the surrogate and rotavirus in aquifer media, as well as rotavirus die-off and DNA degradation, will be compared in laboratory studies. Once this approach is validated, surrogates for many specific pathogens can be made and their retention and transport in groundwater systems studied. The application of this tool could be extended to include surface-waters, soils and sediments. This innovative tool will help to catalyse significant advances in our understanding of pathogen retention and transport, and allow more accurate predictions of contamination risk from pathogens in the environment.

Recipient(s): Dr CK Lee | PI | University of Waikato
Prof SC Cary | AI | University of Waikato
Dr GW Tyson | AI | The University of Queensland

Public Summary: Recent discoveries have transformed our view of microbial ecology in the soils of Antarctic Dry Valleys, which evidently harbour significant and extremely localised microbial genetic diversities that are heterogeneous across physicochemical gradients. We seek to elucidate how local abiotic factors, which are reflective of historical and ongoing geological processes, influence ecologically relevant Dry Valley microbiota. Over two field season, we will carry out a collection of experiments aimed at elucidating the potentially causal relationship between abiotic factors and microbial ecology, and validate our findings through a multi-valley survey. Using a suite of RNA-based molecular genetic techniques, including a metatranscriptomic study, the proposed research will reveal how these microbial communities structurally and functionally respond to abiotic physicochemical variables. Results from the proposed research will elucidate the relationship between soil microbial ecology and the glacial geomorphology of the Dry Valleys; such information will be extremely valuable for predicting how changes in macro-climatic conditions affect the Dry Valley ecosystem and understanding the geological history of the Dry Valleys. Findings from this study can be projected to similar (i.e., oligotrophic, low biomass) habitats worldwide and answer fundamental questions related to the biogeography and dispersal of microorganisms.