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Auckland researchers have made a global breakthrough by successfully building a tiny replica of a protein molecule produced by marine mussels. This remarkable substance may eventually be used to glue together wounds caused by surgery or injury. Led by Dr Carol Taylor, the Marsden-funded team at University of Auckland have used the powers of organic synthesis to make the water-resistant glue that helps mussels stick to rocks. The powerful grip of the adhesives secreted by a gland in the mussel's "foot" is now attracting the attention of the worldwide biotechnology industry. Organic chemistry lecturer Dr Taylor and a doctorate student, Claudette Weir, have recently succeeded in assembling the chain of 10 amino acids, or building blocks, that repeats 75 to 80 times in the protein. This structure gives the protein properties that make it sticky and enable it to create strong bonds. Dr Taylor said that the mussel proteins were proven adhesives in an unforgiving, saltwater environment. "If their properties extend to a situation where they could be used in biological tissues, they will have immense potential as adhesives in medicine. They might be useful to glue cells or tissues together", she explained. Obtaining reasonable quantities of the protein from its natural source for research purposes was difficult, with just 0.4 mg of protein obtained from 200g of mussel feet. "One of our biggest challenges was producing the rarest of the amino acids, dihydroxyproline, not commercially available in any form. Claudette Weir managed to develop an efficient and versatile synthesis that produces hundreds of milligrams of dihydroxyproline in a batch. "Importantly, the strategy is not restricted to that particular amino acid present in the mussel protein; it should provide access to many closely related amino acids. It will be very useful in future work aimed at understanding the role of dihydroxylated prolines in nature." According to Taylor, synthesising peptides, compounds made up of two or more amino acids, is a highly complex exercise where unusual amino acids are involved. "When we started our work, little was known about incorporating these rare amino acids into peptides. "The strategy required fragments of the peptide to be brought together in a carefully controlled manner. The timing and order of chemical reactions were critical to the successful assembly of the 10 amino acid repeating unit, or decapeptide." Another important feature of this approach was the form in which the repeating unit is obtained, she added. "We should be able to combine two, or more, decapeptides in a defined way to produce small versions of the protein. This places us in a unique position to study the role of the unusual prolines and the mechanism of adhesion."
Nano-find could rock disc worldIn a find with big implications for the optical memory industries, a team of Christchurch researchers has been modifying a semiconductor at scales approaching millionths of a millimetre. The discovery could help pave the way for the amount of stored information on compact and digital video discs to be more than trebled. The semiconducting material, called gallium nitride, is important because it promises to deliver the sought-after blue-light laser that allows optical storage media to be read with higher resolution. Working at the nanometre (millionths of a millimetre) scale is vital because it is the scale of a future generation of electronic devices, including miniature lasers. The five-strong Canterbury University team, known as the Nanostructure Engineering Science and Technology Research Group (NEST), is part of a major nanotechnology initiative supported by the Marsden Fund to seed a comprehensive research effort into this 21st century technology. Two staff from Industrial Research Limited are also involved. "Making nanometre-scale structures requires the definition of the mask patterns, for example, using an electron beam of 16 nanometres in diameter," explained team leader Dr Rebecca Cheung from the Department of Electrical and Electronic Engineering at Canterbury. "Subsequently it is necessary to remove the underlying material not protected by the mask with high resolution, using a method known as reactive ion etching – much like corrosion in limestone rock formation." And in the last month, the team has also found that reactive ion etching introduces metastable defects that could be used to store information. "We have been able to write information in particular areas on the gallium nitride with a laser beam, and subsequently read the information, even days after the exposure has been performed. We are now trying to understand the cause of such effects – the answer to which may have tremendous impact in the optical memory industries."
Geckos of the pastWhile the popular myth runs that ancient New Zealand was a land of birds, researchers are now finding that geckos are our most varied group of terrestrial vertebrates. Studying the evolution of these small lizards is therefore the best window for understanding the history of vertebrates in this country. As part of their pioneering work on gecko evolution, diversity and biogeography, Marsden researchers Dr Rod Hitchmough and Professor Charles Daugherty from the School of Biological Sciences at Victoria University of Wellington have compared the DNA molecules of local species with their New Caledonian and Australian cousins. They show that geckos were likely to have been on board New Zealand when it floated away from Gondwanaland some 80 million years ago. "Our results show that all the New Zealand geckos form a single group descended from one common ancestor around 25 to 35 million years ago," Dr Hitchmough explained. "The New Caledonian geckos form a similar group, and the New Caledonian and New Zealand groups are each others' closest relatives. The Australian members of the group are more distant relatives." Hitchmough and Daugherty estimated the time since these groups last shared a common ancestor by comparing levels of genetic divergence between different geckos with those between mammals whose divergence dates have previously been estimated. "The estimated divergence date from the New Zealand and New Caledonian ancestors to the closest Australian sample was about 80 million years, and a separation date of about 65 million years was estimated between the New Zealand and New Caledonian faunas. These figures agree closely with the times when geologists believe that land connections last existed between these landmasses", Dr Hitchmough said. The findings also show that there are more species of geckos in New Zealand "We have known about others for many years, but not recognised them as distinct until the evidence of DNA sequences became available. These results make the New Zealand geckos the largest vertebrate group to have evolved from a single ancestral species in New Zealand. This diversity, combined with their ancient origin, makes them an ideal model for defining the evolutionary history of the whole fauna and flora."
News from Marsden Cottageby Dr Valda McCann, Manager, Marsden Fund
Deadline for applications
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Dr Peter Gilberd has joined the Marsden Fund administration as a senior research assessor. He and Dr Rachel Averill will be visiting institutions to monitor Marsden Fund research. Peter has a PhD in condensed matter physics from Victoria University of Wellington and has done postdoctoral work at Imperial College and Birmingham University in the United Kingdom. He has been employed in both the Crown Research and University sectors. Most recently Peter has been lecturing at Victoria University, and engaged in several collaborative research projects with the Institute of Geological and Nuclear Sciences and Industrial Research Ltd, chiefly in materials science.
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New administration officer,
Rochelle Barton |
Celebration of Marsden research
A function to celebrate fundamental research as supported by the Marsden Fund was held in Dunedin on October 7. The speakers – the Hon. Maurice Williamson, former Minister of Research, Science and Technology, Professor Diana Hill, Chair of the Marsden Fund Committee, Professor George Petersen, President of the Royal Society Academy Council, and Professor Paul Callaghan from Massey University – stressed that support for fundamental research is vital to New Zealand's future.
As part of the evening, five researchers from the University of Otago gave presentations of their Marsden-funded research, assisted by graphic and colourful slides. The time and care put in to these presentations was much appreciated as was the help of Caroline Cook, the Director of the International Science Festival for the Dunedin City Council.
The speakers and topics were:
The audience was drawn from the business, government, civic and research communities. The positive response from those attending confirmed that it was a successful event. The researchersÍ talks have been recorded on video.
Recognising excellence
New Fellows of the Royal Society and the recipients of medals and awards
were announced at the FellowsÍ Annual General Meeting in November.
Nine of the 19 new Fellows and several of the recipients of the medals
and awards are, or have been, also involved in Marsden Fund research.
The Marsden Committee is delighted to see their excellence recognised
in this way. Compliments of the season This is our last issue of Marsden
Update for this year. The Marsden Fund administration looks forward to
meeting more researchers next year and to learning more about interesting
research results for this newsletter. Best wishes for the New Year to
all our readers.
Vegetarian fishes munching on pastures of seaweed rely on similar gut microbes to those of cows and sheep to help digest their food.
Pioneering Marsden-funded research by Drs Doug Mountfort of the Cawthron Institute and Kendall Clements from the School of Biological Sciences at the University of Auckland is showing that these underwater herbivores – just like land-based ruminants – depend on tummy microbes for their daily energy requirements.
"Terrestrial vertebrate herbivores like cows and sheep use symbiotic relationships with gut-dwelling microorganisms to help digest plant material," Dr Mountfort explained.
"The microbes in the gut ferment cell wall components of the diet to short chain fatty acids (SCFA), which are then taken up and used for metabolism by the host animal. We have known for some time that the guts of many marine herbivorous fish have elevated levels of SCFA, in particular acetate."
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A butterfish lying among the dietary alga Ecklonia
radiata at the Poor Knights Islands.
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According to Dr Mountfort, acetate is also the dominant SCFA found in the rumen of cattle and sheep. "Working with intact hindgut sections of freshly caught silver drummer, marblefish and butterfish and introducing acetate into the gut cavity, we found that acetate was produced at similar rates to those found in the guts of other vertebrate herbivores.
"This is the first time the rates of digestion mediated by gut microbes in fishes have been measured, and suggests this form of digestion may be as important for some herbivorous fishes as it is for terrestrial vertebrate herbivores."
A focus of the research was on the conversion of acetate by gut microbes to other compounds, such as methane and sulphates. "To examine this in fish we measured methane production and sulphate reduction in the gut. We found the rates of these processes to be less than the net production of acetate by a factor of almost 50," Dr Mountfort explained.
"This suggests that microbially produced acetate is mainly taken up across the gut wall, rather than being further metabolised to methane or CO2 by gut microbes. Detection of labelled acetate in the blood during the net production studies confirmed this."
Dr Mountfort said the team's results supported the theory that SCFA produced by symbiotic gut microbes provides a significant fraction of the daily energy requirements of these fishes.
"To quantify this fraction we plan to calculate the energy contribution of acetate produced in the gut in relation to the overall energy requirements of these fish. We will therefore need to calculate daily rates of energy intake, and compare these with the amount of energy derived from gut microbes through fermentation."
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For further information, contact
Dr Doug Mountfort at the Cawthron Institute Phone: (03) 548 2319 Email: doug@cawthron.org.nz Address: Private Bag 2, Nelson Dr Kendall Clements, School of Biological Sciences, University of Auckland Phone: (09) 373 7599 ext. 7223 Email: k.clements@auckland.ac.nz Address: Private Bag 92019, Auckland |
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Professor Andrew Carstairs-McCarthy,
holding an anatomical model of the human head. (Photo: Duncan Shaw-Brown) |
Did human speech take a great leap forward the moment that our pre-human ancestors' larynxes dropped into their current positions?
This dramatic physical change meant that, unlike other primates, humans could no longer swallow and breathe at the same time. But the fall of the larynx may have helped create complex language, as we know it today.
Marsden researcher Professor Andrew Carstairs-McCarthy believes that greater scope for sounds from a lowered larynx led to more sophisticated language. He is challenging views that the evolution of language was the spur for improved speech – and not the other way around.
In the book, The Origins of Complex Language, published this year by Oxford University Press, he presents evidence to build the case for an evolutionary argument with clear-cut, testable implications for language as it is today.
Based at the Department of Linguistics at Canterbury University, Professor Carstairs-McCarthy reconciles evidence from grammar with what is known about evolution of the brain and the vocal tract, and about the communicative abilities of other primates. He suggests that control of the vocal tract is the key to the way language developed.
"Linguists are interested in distinguishing those aspects of grammar that are peculiar to languages such as English or Japanese, from those that are common to all human languages – aspects that belong to 'Universal Grammar'," he says.
"But what about conceivable alternatives to Universal Grammar itself? We cannot truly claim to understand language until we have compared grammar as it is with grammar-as-it-might-have-been, and suggested reasons why Universal Grammar does not conform to one of these alternative patterns."
Professor Carstairs-McCarthy wants readers to consider various alternatives,
to help challenge the tendency to assume that grammar-as-it-is is the
only way that grammar can be.
"Even the distinction between sentences and noun phrases turns out to be not inevitable nor even particularly 'natural', from the point of view of either communication or knowledge representation. Why does it exist, then?
"The answer lies in how natural selection operates. Evolution does not arrive at perfect solutions to design problems; rather, it tinkers with what happens to be available. So characteristics of language that are not 'functional' in its current environment may for that very reason be particularly revealing about its evolutionary history."
Professor Carstairs-McCarthy believes some central but puzzling characteristics of syntax can be understood in this fashion. "They fall into place as left-overs of a kind of organisation which evolved originally for a purpose that has nothing to do with syntax, but which happened to be available for syntatic tinkering. That was the organisation of the consonants and vowels of articulate speech into syllables," he argues.
"Seen in this light, certain classic puzzles about grammar dissolve. The notion 'subject' in syntax is notoriously difficult to define in a way that fits all languages. But this difficulty is not mysterious if 'subjects' have nothing fundamentally to do with meaning, but are just one of the syntactic left-overs of an aspect of syllable structure, namely the initial consonant cluster, or 'onset'."
Within linguistics, he says, it is not just evidence from syntax that supports his conclusions. "Outside linguistics, too, my book has startling implications for logic and the philosophy of language. The distinction between reference and truth is closely tied to the distinction between noun phrases and sentences.
"But philosophers and logicians who might have been expected to supply a solid non-grammatical reason for the distinction between reference and truth fail to do so. This distinction may thus be a mere byproduct of the distinction between noun phrases and sentences – which in turn comes from syllable structure, when it was tinkered into a basis for syntax.
"If this is right, then the distinction between 'declarative' knowledge ('knowledge-that', expressed in sentences) and 'procedural' knowledge ('knowledge-how' which is not so dependent on language) dwindles in significance. Only humans have declarative knowledge, perhaps – but that can no longer be regarded as major Rubicon in cognitive evolution."
Professor Carstairs-McCarthy says his conclusions are likely to be controversial. "But, however the debate on them develops, I hope to have shown that fruitful inquiries can result from comparing grammar-as-it-is with other alternatives in the space of possible grammars."
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For further information, contact
Professor Andrew Carstairs-McCarthy, Associate Professor, Department of Linguistics, University of Canterbury Phone: 64–3–364 2211 Fax: 64–3–364 2969 Email: a.c-mcc@ling.canterbury.ac.nz Address: Private Bag 4800, Christchurch |
Economists now attach a lot of importance to the way in which what is called "human capital" is spread over the population. This spread is judged as important as the rate of investment or population growth in determining a nation's earning potential.
But solid data to help measure this key determinant of growth – defined as the economic value of a person's skills – has long been elusive.
In a Marsden-funded project, University of Auckland economist Debasis Bandyopadhyay has developed a formidable database across 119 countries to come up with fresh ways to measure human capital. Dr Bandyopadhyay's pioneering findings are attracting widespread interest in financial quarters.
One of his key findings is that countries with disparate per capita income in the 1990s had quite different spreads of human capital in the 1960s.
He has developed a new statistic to describe a country's human capital.
"This statistic describes the quality of the labour force and measures the ratio of adults in the labour force with a high level of education to those with a low level," Dr Bandyopadhyay explained.
"The ratio has turned out to be a simple but significant predictor of the per capita income of a country. In particular, by noting the variation in that ratio alone we can explain about three-quarters of the cross-country disparities of per capita income.
"This finding is quite surprising, since the conventional and the most frequently used growth models explain only between 56 and 68 percent of these differences within the same database."
Dr Bandyopadhyay said that the spread of human capital in the population does better than conventional growth predictors such as population growth rate and investment rate.
"In particular, the proportion of adults with no qualification is
a reasonably good predictor of a country's population growth rate and
the proportion of adults with education beyond secondary level can reason
ably predict a country's rate of investment.
"We conclude that the distribution of human capital plays a more fundamental role than the conventional predictors of long-run growth."
Dr Bandyopadhyay said cross-country diversities in the trends of the human capital distribution were especially interesting.
"Most importantly, we find that today's so-called rich countries as well as countries that experienced a intermediate rate of long-run growth started with a significantly higher proportion of educated adults than others.
"The ratio of the number of educated to uneducated adults has increased in all countries over time. Interestingly, the ratio remains high among the rich countries and low among the poor countries. We found no evidence of a worldwide convergence of this ratio over time.
"In poor economies characterised by the scarcity of educated adults, a lowering of income-inequality corresponds to a more rapid economic growth. In rich economies with relatively abundant supply of educated adults, the growth-inequality relationship turns out to be quite the opposite."
How much available knowledge would be exploited in an economy depends on the ratio of skilled innovators to unskilled labourers, Dr Bandyopadhyay added.
"A redistributive tax reform involving a tax on income to subsidise education lowers the private cost of acquiring skill but also reduces the relative proportion of innovators in the economy by adversely affecting the after tax returns from innovating activities. The trade-off implies a formula for designing an optimal scheme of redistribution of income through the tax and welfare systems to help the economy reach the frontier of its growth potential."
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For more information, contact
Dr Debasis Bandyopadhyay at the Economics Department, University of Auckland Phone: (09) 373 7599 ext. 7439 Fax: (09) 373 7427 Email: debasis@auckland.ac.nz Address: Private Bag 92019, Auckland |
A team of wellington-based Marsden researchers is getting to grips with a remarkable new material that is simultaneously both a ferromagnet and a superconductor.
The material, an oxide of ruthenium and copper, was discovered by Dr Jeff Tallon in 1997 in his research under a James Cook Fellowship. His ground-breaking work is continuing with the help of Professor Joe Trodahl, from Victoria University of Wellington, and fellow Industrial Research Ltd researcher, Dr Grant Williams.
Intended to be a "designer" superconductor with the ability to carry very large electrical currents, the astounding discovery was of a material that was not only superconducting, but also magnetic. This turned on its head the long-held belief that superconductivity and magnetism were mutually exclusive.
"This material breaks all the rules. The exploration of the physical world is full of such surprises – the serendipity of pursuing a particular path of investigation when something new and quite unexpected emerges," Tallon says.
He recalls that the seeds of this discovery were sown 10 years earlier.
"We were exploring the effect of substituting sodium in high-temperature
superconductors, in order to enhance the diffusion of oxygen, and a new
impurity phase appeared. This led to the discovery of Y2Ba4Cu7O15
(also known as "2-4-7"), which proved to have the best current-carrying
performance of any high-temperature superconductor."
"The reason why these 2-4-7 materials perform so well is that they
have chains of alternating copper and oxygen atoms lying between active
copper oxide planes in which superconductivity occurs. These chains proved
to be metallic and although not intrinsically superconducting they are
induced to be so because of their closeness to the active planes. This,
in turn, strengthens the coupling between the active planes and makes
the material able to sustain very high currents. This led to a new design
criterion for synthesizing high-performance superconductors – that
of incorporating a metallic interlayer between the active planes in novel
structures."
A further clue came from the discovery in Japan of superconductivity in an oxide of strontium and ruthenium. "What interested me here was not the superconductivity (which occurred only at very low temperatures) but that, in this compound, the ruthenium occurs in oxide layers which have the same bonding characteristics as copper in the high temperature superconductors. Moreover, these ruthenium oxide layers are clearly metallic. Why not then incorporate ruthenium oxide layers between copper oxide layers in a "designer compound" which would thereby carry very large currents?"
During his recent James Cook Research Fellowship, Tallon synthesized several of these hybrid materials and, together with Christian Bernhard at the Max Planck Institute in Stuttgart, investigated one, in particular. "We worked with it off and on for a period of about 10 months before we realised that this material is not only a superconductor but a ferromagnet," he recalled.
"This was not just unexpected; it was highly unlikely. Ever since studies by the Russian theoretician Ginsberg more than 40 years earlier, it had been believed that ferromagnetism and superconductivity were incompatible. Yet here was a material which, on cooling, became a magnet (at –141°C) and then, at the same time, also a superconductor (at –223 °C).
"Working pretty feverishly and often in connection with other collaborators, we have completed a vast range of studies over a few months: magnetoresistance, thermopower, magnetic studies, Raman scattering, heat capacity, NMR, electron spin resonance, muon spin rotation, isotope exchange, synchrotron x-ray diffraction and neutron diffraction."
These studies indicate that, contrary to expectation, the superconductivity and magnetism do not accommodate each other by separating into a patchwork of separate islands of each, as has been observed in some exotic materials. The two states uniformly co-exist by having quite different symmetries.
Dr Tallon believes a rich array of exotic phenomena wait to be explored in these materials with many magnetic and superconducting states all competing. "Nature's treasures can be slowly and systematically mined, but from time to time one simply stumbles on a rare nugget of great value."
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The structure of the oxide, RuSr2GdCu2O8,
in which superconductivity and ferromagnetism co-exist. The copper oxide planes are at the base of the pyramids, with the ruthenium oxide planes at the centres of the octahedra. The copper oxide layers are separated from each other by the gadolinium ions and from the ruthenium oxide layers by sheets of strontium oxide. Oxygen atoms sit at the apices of the polyhedra. |
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For further information, contact Email: J.Tallon@irl.cri.nz Address: P O Box 31310, Lower Hutt |
The Marsden Fund supports excellent research, in a wide range of topics covering the sciences, social sciences, humanities and engineering.
Each year, Government provides funding for projects that will foster research of the highest calibre. This is work not subject to government priorities but will nonetheless enhance New Zealand's ability to participate in, and benefit from, research of an international standard. Set up in 1994, the Marsden Fund is a contestable fund administered by the Royal Society of New Zealand.
A Marsden Fund Committee of 10 eminent researchers, chaired by Professor Diana Hill, is appointed by the Minister of Research, Science and Technology to make recommendations for funding. Selection criteria focus on the merit of the proposal, the potential of the researchers to contribute to the advancement of knowledge, and the enhancement of research skills in New Zealand, especially those of emerging researchers.
Eight panels have been established to help the Marsden Fund Committee assess proposals. These are:
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For more information and application forms, Phone: (64–4) 4728345 |
The Marsden Fund, c/o the Royal Society of New Zealand, 9 Turnbull St,
Thorndon, P O Box 598,
Wellington, New Zealand.
Tel: +64-4-4728345; Fax: +64-4-4731409; Email: marsden@rsnz.govt.nz
The Chief Executive Officer, the Royal Society of New Zealand, P O Box 598, Wellington
All our news appears on the Royal Society of New Zealand's website:http://www.rsnz.govt.nz/
