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MARSDEN FUND NEWSLETTERNo 23 · April 2003
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| Girls dance the final, fast movements of a toha. |
Associate Professor Richard Moyle, from The University of Auckland, is one of only four researchers who have been allowed to work on the island. His fieldwork, which has spanned six years to date, responded to a community wish to record for the children who have left the island to attend secondary school its strong tradition of singing and dancing.
The 180 adults on the island, which lies 200km off Bougainville's east coast, have an active repertoire of at least 1000 songs, with 50 more added each year. (After the 1000th, Professor Moyle stopped recording and started participating in the rehearsals and performances.) The performances, which range in topic from castigating the losers of fishing competitions to forcing unwilling dance partners to join in, last on average 20-30 hours each week.
The Marsden Fund supported three years of Professor Moyle's fieldwork, which has now produced two books on the island. In addition to the musical ethnography, an anthology of fables the first bilingual book in Takuu Atoll's own language is expected in print this year. A bilingual collection of history and prehistory will follow in 2004.
Professor Moyle is also following up two further community requests: funding for replacement classrooms for the community school, and for a dictionary in the local language. Funding for the dictionary project has been secured and formal fieldwork will start this year.
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| The anu haikave dance, in which women force the men, whom they would normally avoid, to dance with them. |
This push to compile some of Takuu's unique history is not without urgency because the atoll is sinking so fast, much of the land is now less than a metre above sea level. Furthermore, salt contamination of groundwater is rapidly shrinking the area available for gardens. Within a few years, the entire community will have to be moved. The Papua New Guinea Government's attempts to fund relocation for the islanders, possibly to Bougainville, have so far failed. Increased press coverage, such as a 30-minute programme from TVNZ's Tangata Pasifika team (which has been broadcast three times to date), has generated much interest in the islanders' plight. But the situation still remains unresolved.
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For more information, contact Associate Professor Richard Moyle Department of Anthropology The University of Auckland Private Bag 92019, Auckland Tel: (09) 373 7599 ext. 88983 Email: r.moyle@auckland.ac.nz |
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| University of Canterbury researcher Dr Roger Dungan measuring photosynthesis of beech trees. |
The sweet smell of fermenting honeydew is a distinctive part of many a summer walk through New Zealand beech forest, and the insect that produces it is known to be an important part of the forest ecosystem. But now a trio of Canterbury University researchers is suggesting that the sap-sucking scale insect might even help the productivity of their host trees.
The beech honeydew insect, millions of which can be found in a hectare of forest, live in the bark of beech trees and suck their sap. The insect retains the proteins and nutrients from the sap, but excretes excess carbohydrate through hair-like anal tubes that extend visibly a couple of centimetres from the tree. Little is known about the life cycle and mating habits of this tiny mysterious insect, but it is known that the sugar-rich honeydew it produces is an important energy source for fungi, birds, and insects.
A Marsden-funded project, led by Associate Professor Dave Kelly and Dr Matthew Turnbull at the University of Canterbury, has focused on the beech-honeydew system from the tree end of the relationship.
The team, which includes postdoctoral fellow Dr Roger Dungan, analysed four days of honeydew production data from 57 trees in the Craigieburn Range. They found that honeydew production is strongly influenced by host trees. Some trees were able to support higher concentrations of insects, and insects on these trees tended to produce more honeydew per insect. It appears that certain trees can consistently sustain greater numbers of more productive insects.
What's more astonishing is the lack of effect that even massive infestations of insects have on host trees. It has been estimated that the scale insects can suck more than half of the carbohydrate that beech trees produce through photosynthesis, energy losses that should be enough to adversely affect tree growth and competition. But while not all trees support scale insects, those that do so seem unaffected by the massive drain on their system.
This is because, the Canterbury researchers argue, the scale insects are increasing
the ability of the trees to photosynthesise by removing an end-product limitation
to photosynthesis. The starches and phosphate-rich sugars of photosynthesis
can otherwise accumulate in leaves, tying up compounds that are needed for photosynthesis.
By drawing off sugars that would inhibit photosynthesis, the honeydew insect
canincrease the carbon fixation of thebeech trees.
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| The hair-like wax tubes of scale insects, supporting drops of sugar-rich honeydew. |
Further field work by the team, this time in the Canterbury foothills near Mt Grey, supports this hypothesis. By directly measuring photosynthesis, the researchers found that the leaves of trees with more scale insects were taking up carbon at a higher rate.
The team is about to test this idea further by partially shading trees. Normally this procedure would increase photosynthesis for the unshaded leaves. The shaded leaves, which are photosynthesising less, will require carbohydrates to be transported from the unshaded leaves to provide their energy needs. As in the case of a honeydew insect infestation, the transport of sugars away from unshaded leaves can increase their photosynthetic rates. But if the insects have already increased the rate, shading part of the tree may not push it up much further. The sun/shade difference in photosynthesis for trees with scale insects, the researchers predict, will be lower than that for trees with few insects.
More work is needed to understand the mechanism by which sap dynamics might
increase photosynthesis. But if the researchers are right, then scale insects
are effectively "farming" the trees, increasing productivity across
millions of hectares of beech forest.
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For additional information, contact
Dr Roger Dungan Department of Plant and Microbial Sciences University of Canterbury Private Bag 4800, Christchurch Tel: (03) 366 7001 ext. 4847 |
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April has been a busy month with preliminary proposal assessment meetings at the beginning of the month and then the Marsden Fund Council meeting on 17 April to make the final decisions on which preliminary proposals for 2003 would be invited to submit full proposals.
This year, there were 741 preliminary proposals 612 standard proposals
and 129 Fast-Starts. This is a decrease on the number compared to last year
when 674 standard and 130 Fast-Start proposals were received. The reduction
in the number of standard proposals is a consequence of the new restriction
placed this year on the number of preliminary proposals that a researcher can
be listed as a Principal Investigator.
Numbers of preliminary proposals and invitations to submit full proposals, by
panel. Thenumbers include proposals sent to more than one panel, so adding
up the number of proposals in each panel gives a total greater than the number
of separate proposals given above. Lastyear's figures are given in brackets.
| Panel |
No. of Fast-Start Proposals
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No. of Standard Proposals |
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Preliminary
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Full
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Preliminary
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Full
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| Biomedical Sciences |
14
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(9)
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5
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(2)
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87
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(107)
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18
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(20)
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| Cellular, Molecular & Physiological Biology |
14
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(11)
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5
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(2)
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103
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(115)
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22
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(20)
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Ecology, Evolution and Behaviour |
18
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(20)
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4
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(4)
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99
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(125)
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20
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(22)
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| Earth Sciences and Astronomy |
12
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(8)
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3
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(2)
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61
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(79)
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12
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(15)
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| Humanities |
7
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(16)
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3
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(4)
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43
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(39)
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9
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(10)
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Mathematical and Information Sciences |
12
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(15)
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3
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(3)
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53
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(58)
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12
|
(13)
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|
Physical Sciences and Engineering |
15
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(17)
|
4
|
(4)
|
111
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(99)
|
23
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(19)
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| Social Sciences |
41
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(40)
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10
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(8)
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89
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(91)
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19
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(18)
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| Total |
133
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(136)
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37
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(29)
|
646
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(713)
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135
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(137)
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Tasha
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Janet
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We have had a number of staff changes this year. Rachel Averill is taking a period of parental leave and will re-join us later in the year. Jason Gush, who was employed as a Research Assessor on a casual basis, has now formally joined the staff to cover Rachel Averill's duties while she is on maternity leave. Dr Tasha Black was appointed as a Research Assessor at the end of March. Tasha has a PhD in geology from Victoria University of Wellington and postdoctoral experience at the University of Toronto in Canada. She held a curatorial position at Auckland Museum before moving to the Royal Society in 2001 as Promotions Manager and, after 6 months maternity leave, has returned to work at the Marsden Fund. Janet Sorensen joined us in February as a part time Administration Officer.
Since the discovery, less than five years ago, of how to isolate stem cells from human embryos, the possible uses have caused great excitement in the world of medicine. These are the cells from which all the tissues of our bodies have developed from the cells of a beating heart to those producing insulin in the pancreas.
Because many medical problems cause damage to tissue, the prospect of growing new cells offers possibilities for healing that have hardly been dreamed of in the past. New treatments for Alzheimer's and Parkinson's diseases through the growth of new neural tissue or the repair of muscles, organs or spinal damage, offer the promise of complete rehabilitation.
If the possibilities are so vast, why are there problems with advancing the research necessary to realise them? The major problems are ethical.
Each of us developed from a single cell which, in a 3-5 day old embryo, has multiplied to about 30 cells. These are stem cells, which finally give rise to the hundreds of different kinds of tissue needed to make an adult organism. Such cells are unusual because they can renew themselves for long periods of time without becoming specialised, but under certain conditions can be induced to change to a specific function.
Such cells could be grown in great numbers in the laboratory, then changed into whatever kind of tissue was needed from skin to neural cells. All that is needed to achieve such a transformation is the trigger that causes development togo in one direction rather than another.
The most promising stem cells for research are those from the very early embryos. But adults have stem cells too, and the potential of these is currently an area of much dispute. Adult stem cells were recently found in many more tissues than scientists had thought possible our hearts and brains, we now know, can grow new cells. If adult stem cells can be changed into all types of tissue, maybe embryonic cells are not needed. But it is proving difficult to prove that adult cells have such powers.
Using embryonic cells has difficulties more of the ethical kind. If embryos were regarded as having a moral status akin to, or identical with, that of living human beings, using them for medical purposes even those which helped others heal could be considered immoral. Discussions about this issue are polarised and it is unlikely that a consensus view will be found.
Certainly, political interventions around the world have brought contradictory legislation between countries. In Britain, laws allowing scientists to develop embryos up to the age of 14 days solely for research purposes recently withstood appeals by anti-abortionists. Australia, in line with Britain, has enacted federal legislation that allows research on embryos, including the use of embryonic stem cells. The USA has a more restrictive law, limiting embryonic stem cell research to embryos that were already in existence in August 2001. In non-Commonwealth countries, such as Germany and France, the policies have generally been less pragmatic. There, laws were enacted to control embryo research and assisted reproduction before the potential of embryonic stem cells was known. Researchers have made every effort to persuade legislators to change these laws, but any change would involve major expense and legislative time. These legal systems have thus produced an inertia that has been favourable towards objectors toembryonic stem cell research.
At present, stem cell research using human embryos is not being conducted in New Zealand. New legislation covering such issues is currently being considered by Parliament. New Zealand can learn from the precedents in other countries. There are implications for the future of young scientists, the health of citizens, the welfare of children, and the determination of public policy in this area.
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For more information, contact Professor Donald Evans Bioethics Centre Department of Medical and Surgical Sciences University of Otago P.O. Box 56, Dunedin Tel: 03 474 07007 ext. 8121 |
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| A three-dimensional molecular picture of the enzyme, type II dehydroquinase. |
By blocking biochemical reactions similar to those targeted by the herbicide Roundup,, researchers from the University of Canterbury are hoping to create new antibiotics that can kill diseases like tuberculosis while keeping the stomach's natural bacteria, such as E. coli, alive.
The trick to such selective killing lies with the biosynthetic pathways that are used to build molecules. The shikimate pathway helps build aromatic compounds such as the aromatic amino acids (essential building blocks for proteins); the flavonoids, which give colour to flowers and insect wings; dietary essentials such as vitamin K and folate; and some important alkaloids including morphine, strychnine and lysergic acid (a precursor to LSD). The shikimate pathway only occurs in plants and microorganisms, never in animals. It is because the pathway is absent in humans that we must obtain nutrients like the aromatic amino acids and vitamin K through our diet.
This absence of the shikimate pathway from mammals makes it an appealing target for the design of new types of antibiotics and herbicides. Roundup's, active ingredient glyphosate binds to and inhibits the enzyme which catalyses the sixth step of the shikimate pathway. Associate Professor Andrew Abell, Dr Christine Le Sann, and PhD student Mary Gower, in collaboration with a group in Cambridge, are focusing on the enzyme that catalyses the third step dehydroquinase. Dehydroquinase is an interesting enzyme because there are two types (I and II) which catalyse the same step by different methods. This means it is possible to design an antibiotic which will treat a disease such as tuberculosis, which has the type II enzyme, without depleting microbes such as E. coli, which has the type I.
The challenge that faces the group is to design compounds that bind tightly enough to the active site of type II dehydroquinase to prevent the enzyme from performing its designated function.
The researchers are using some known compounds as a starting point to build more potent inhibitors. They will synthesise such an inhibitor from a likely compound, then test it to see how well it works. X-ray crystallographic studies can then provide a molecular picture of how the inhibitor is bound to the enzyme, giving clues as to how it might be modified to bind more tightly. This cycle of biological testing, design modification and synthesis of new inhibitors must be followed until the inhibitor is potent enough to be a viable antibiotic. The search for novel and new antibiotic compounds is likely to be long, but with the increasing resistance of microorganisms to conventional antibiotics, it is as exciting as it is vital.
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For more information, contact
Associate Professor Andrew Abell Department of Chemistry University of Canterbury Private Bag 4800, Christchurch Tel: (03) 364 2818 |
In recent years, the picture of reef fish larvae as passive passengers on ocean currents has collapsed under evidence of their enviable swimming capabilities. Though sometimes only millimetres long, reef fish larvae can consistently swim faster than the currents they float in individual cases have shown larvae to have travelled a total of more than 200 km.
But exactly how the fish home in on a reef has remained unknown. Researchers
suspected that the secret might lie with the sounds a reef makes underwater
the symphony of clicks, pops, and clacks that even an unaided human ear
can hear. Marsden-funded researchers from The University of Auckland have now
confirmed this theory.
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| The University of Auckland team, in collaboration with scientists from the Australian Institute of Marine Sciences, are seen here clearing a small artificial reef patch in the lagoon at Lizard Island on the Great BarrierReef. By removing the newly settled reef fish each day it is possible to count the number of new fish arrivals. Replaying reef sound in particular areas significantly increases the rate of larval settlement. |
The team, led by Professor John Montgomery, put light traps playing imitation reef noises out at night near Leigh Marine Reserve, in Northland. They found that those traps with sound caught three times as many fish as traps without. The work has been repeated, with similar results, for the coral species on Great Barrier Reef.
The researchers found rather different results during the day larval fish swim away from the reef when it is light to avoid thedangerous "wall of mouths" formed by plankton-eating fish. At night, when these predators are asleep, the larvae can return to the reef.
The next step for the team was to understand what fish hear that attracts
them to reefs. Fish don't hear in the same way as humans their ears are
more like our otolith bone in the inner ear, which lets us know when we are
upright. That means fish simply detect the accelerations of sound waves, and
have no obvious
way of telling the direction the sound is coming from. Some fish have small
air bubbles in their bladder that help them process sounds, but the fish under
investigation by Professor Montgomery's team did not. To make things more difficult,
sound travels so fast underwater that even human ears have difficulty pinpointing
particular sound sources.
Despite all this, the researchers found that the fish could determine the direction of sound. Put in a T-shaped chamber that allowed them to choose to swim in one direction or another, most fish swam towards the replayed reef sound.
In addition to investigating how the fish figure out sound direction, the team now aims to find out exactly what it is about the reef's noise that draws them in a particular component of the sound, such as breaking waves or biological noises, or the overall ambient noise of the reef.
The answer to that could have wide-reaching implications. If fish are attracted by the crooning of their peers, then areas emptied of fish through overfishing may be slow to re-colonise. Or, if fish only sense less specific noise, there is a danger that anthropogenic noises could draw them into unsuitable areas. A better understanding of the underlying sensory and behavioural mechanisms will help theactive management of reef fish populations in the future.
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For more information, contact
Professor John Montgomery Department of Marine Biology The University of Auckland Private Bag 92019, Auckland Tel: (09) 373 7599 ext 87208 Email: j.montgomery@auckland.ac.nz |
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| PhD student Rebecca Sharp (left) and Dr Sally McCormick. |
While millions hope to beat heart disease by lowering their dietary cholesterol, the level of one particular form of "bad cholesterol" is largely determined by genetics. Changes of diet and drugs have little effect on lipoprotein(a), but now Marsden-funded researchers have designed a molecule that may well curb this cardiovascular risk factor directly.
Lipoprotein(a), or Lp(a), is a cholesterol-rich molecule which tends to get trapped in the walls of arteries, where the build-up of waxy cholesterol can block the vessel and cause artherosclerosis. No current drug can safely reduce Lp(a) levels, and many large clinical trials have shown that it is a risk factor for heart disease. To make matters worse, Lp(a) levels have little to do with better known forms of "bad" cholesterol that can be effectively lowered with statins.
With their knowledge of how Lp(a) forms, University of Otago researchers Dr Sally McCormick and PhD student Rebecca Sharp designed a synthetic peptide that inhibited the production of Lp(a) in vitro. But before they could begin testing in a biological system, they had to improve their molecule's effectiveness.
To do this, they teamed up with Dr Matt Perugini from the University of Melbourne. Together the researchers showed that the peptides that were more helical were better at stopping Lp(a) formation. Dr Alan Hayman at the University of Otago also stepped in to confirm the helical structure of the peptide with nuclear magnetic resonance measurements. In the latest design improvement, the team has shown that combining the peptide with a lipid greatly enhances its inhibitory activity. All up, their peptide with lipid is 2500 times more effective than other compounds used to inhibit Lp(a) in vitro. This research has just been published in the American Heart Association Journal, Atherosclerosis, Thrombosis, and Vascular Biology.
Dr McCormick also recently presented the research at an Lp(a) workshop run by the National Heart, Lung, and Blood Institute at the National Institutes of Health, Washington. "Our research generated a lot of interest from clinicians and there was uniform agreement at the workshop that a drug specifically designed to reduce Lp(a) levels was needed," she said.
The pair will now seek funding for further in vivo testing of their peptide, the next step on the road to potential clinical use. They are confident that the work will spark interest from cardiovascular drug companies.
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For more information, contact
Dr Sally McCormick Biochemistry Department University of Otago P.O. Box 56, Dunedin Tel. (03) 479 7840 |
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| Associate Professor Merv Merrilees (left), PhD student Robert Huang and senior technician BrentBeaumont, from The University of Auckland, examine an image showing the increase of elastin synthesis in cells containing the antisense gene. |
For nearly a century it has been known that cholesterol deposits in arteries occur in close association with molecules called matrix proteoglycans or mucopolysaccharides as they were once called. It is now known that these matrix proteoglycans, which are large negatively charged molecules shaped somewhat like miniature bottlebrushes, bind to cholesterol and set off an inflammatory reaction that results in the atherosclerotic lesions that cause heart attacks and strokes.
Matrix proteoglycans contribute to heart disease in other ways too. One of them, a problematic molecule called versican, stimulates the cells of vessels into growth that leads to thickening of vessel walls. Furthermore, versican inhibits the formation of elastin, making vessel walls less elastic.
Recently, Associate Professor Merrilees, and colleagues at the University of Washington, made the serendipitous discovery that inserting a gene for a miniature form of versican into the cells of the vessel walls not only slowed their growth, but also switched on the synthesis of elastin. Importantly, this new elastin formed functional fibres; the researchers now think they know how this mechanism works.
Elastic fibres are assembled at the surface of cells with the aid of an elastin-binding protein. This molecule acts like a docking station, linking together the units that make up the fibres. Versican stops this assembly process. The sugar chains, or bristles of the brush, cause the elastin-binding protein to fall off the cell surface.
The miniature form of versican doesn't do this, because it doesn't have any sugar chains basically it is just the handle of the brush. As a result, elastin-binding protein stays on the cell surface and assembles elastic fibres.
Clearly, being able to decrease the amount of the large form of versican in the vessel wall would have several benefits. The vessel wall would be thinner, more elastic, and would not trap and bind cholesterol.
The team's Marsden-funded research was aimed at doing just that, and they have now found a new and very effective way of reducing versican and switching on elastin synthesis. In association with Professor Tom Wight's Matrix Biology group, at the Hope Heart Institute in Seattle, they constructed an antisense gene, which stops the formation of the large form of versican. After inserting this gene, the vessel cells showed markedly reduced versican production, reduced growth, and a striking increase in elastin fibre formation.
The researchers next step is to seed the cells containing the antisense gene into blood vessels that have had their lining scraped off with balloon angioplasty. Cells placed into the vessel will stick on and form a new inner wall. They then aim to see if they can create a new vessel wall that does not grow and thicken and which, at the same time, is enriched in elastin fibres. Finally, they will test the new wall for its ability to remain free of cholesterol deposits in the face of high levels of cholesterol in the blood.
If all this succeeds, the team will introduce the antisense gene into cultured human vessels from heart transplant patients, hoping to create new vessels from old.
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For more information, contact
Associate Professor Mervyn Merrilees Department of Anatomy The University of Auckland Private Bag 92019, Auckland Tel: (09) 373 7599 ext. 86056 Email: m.merrilees@auckland.ac.nz |
A long-time filler for white paint, the inorganic chemical zinc oxide (ZnO), is coming into its own in creating a new kind of coating for electromagnetic wave screening or solar cells. ZnO has an unusual attribute it can be made to be both conducting and transparent, so that the windows of the future could double as solar-powered photovoltaic cells.
ZnO also has attractive photoemission properties when electronically excited it emits light. This means that ZnO is a good candidate for the production of light emission diodes for electronic displays and lasers for telecommunications.
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| Zn and ZnO nano-structured thin films formed by different processes. Top-left: cross-section of sputtered Zn film on glass substrate; top-right: doughnut-shape ZnO formed after oxidation of Zn film; bottom-left: whisker-shape ZnO; bottom-right: directly sputtered ZnO. |
But exactly why ZnO behaves as it does is not well understood. Auckland University materials scientist, Professor Wei Gao, and his group have a Marsden grant to investigate how the electronic properties of ZnO are affected by the size and shape of crystal grains, bythe presence of impurities, and by theelectronic charge distribution.
They use a magnetron, the type of power source used in microwave ovens, to vaporise zinc and zinc oxide. The zinc deposits as a thin film on glass and formsZnO when exposed to oxygen during, or after, the deposition. The team can accurately control the size, shape andcomposition of the films' nano-crystal grains by varying the processing conditions, for example the pressure of oxygen and the deposition power source.
The group also includes Associate Professor Jim Metson, Drs Zhengwai Li and
Michael Hodgson, and research students Jim Lee and Ravi Harikisun. They will
investigate the relationship between processing and properties, with a view
to optimising the electronic properties and developing opportunities for ZnO
and other oxide semiconductor materials in electronic applications.
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For further information, contact
Professor Wei Gao Department of Chemical and Materials Engineering The University of Auckland Private Bag 92019, Auckland Tel: (09) 373 7599, ext. 88175 Email: w.gao@auckland.ac.nz |
Seventeen scholars from around the world congregated from 9-12 January at the University of Canterbury to debate "Military Culture in Imperial China (221 BC AD 1911)." This Marsden-funded conference followed in the tracks of two previous investigations into Chinese warfare, "Chinese Ways of Warfare" (Dedham, Mass. 1969) and "Military Thought and Practice in Chinese History" (Cambridge, 1997). The central aims of the conference were to assess the extraordinary development that this field has undergone over the past several years, and to develop a roadmap for its future growth.
It is well known that China has a long history, sophisticated culture, one-fifth of the world's population, and a respected international voice. This makes China one of the most powerful nations on Earth, an achievement often seen as the result of much suffering: colonial oppression, civil wars, and revolution. So while violence is not alien to Chinese history, we know little about how the Chinese have historically related to war how Chinese society organized itself to face invaders, cope with rebellions, arm its soldiers and train its generals.
The broad consensus among China historians is that our information is limited because the elite civil officials had a strong anti-military bias; war was never a favourite subject of historical writing. That bias, reflected in the scant attention paid to military details in the otherwise plentiful sources, has limited the ability of modern scholars to explore traditional areas of interest to military historians such as military institutions, military technology and logistics, and strategic, operational and tactical issues. Less specialised topics such as battlefield experience, women's role in the war effort, and the social impact of returned veterans have received even less coverage.
Compared with other regions of the world, there are few books in English on pre-modern China's military history. Books on that period, which spans Roman times to the Great War, can be counted on two hands, if military texts such as the ever-popular Sun Tzu are excluded.
But the variety and range of the papers at the recent conference showed that while there may indeed be inherent limitations to what can be learnt about China's military past, the exploration of the field has by no means exhausted all sources. Thousands of specialised military manuals and other works related to military matters have yet to be explored.
A key issue discussed by the conference participants was the relationship between Chinese military history and its Western counterpart. An advantage of close contact with the West is that the development of "world" history has meant Western military historians are more receptive towards Asian history, creating an interested, specialised audience that can objectively support the growth of the field. By studying different patterns of development within a given society, comparative history can provide both sides with valuable insights, and help correct facile generalisations.
Dr Di Cosmo says, "China historians shouldn't simply play catch up with the West; Chinese military history must be studied on its own terms. This means that questions need to come from the Chinese, not the European, context, including how military information was recorded in Chinese historiography, how battles were fought on Chinese soil, and how military institutions evolved according to the perceived needs of China's society.
"Whether one follows the 'comparative' route or gives priority to the Chinese tradition, there is no doubt that knowing more about the growth and transformation of military institutions will lead to a deeper understanding of long-term trends that underlay the development of Chinese society. The conference in Christchurch can be regarded as a milestone in the progress of a global effort to move Chinese military history from the obscure to the accessible."
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For more information, contact
Dr Nicola Di Cosmo History Department University of Canterbury Private Bag 4800, Christchurch Tel: (03) 364 2527 |
Since the 17th century invention of differential equations, mathematicians have struggled to solve dynamical systems with an increasingly complicated toolbox of transformations and approximations. Statisticians, and others focused on finding applications in the real world, have taken on the tangential task of estimating the equations that mirror life.
Some of the variables best described by stochastic differential equations are those of finance and economics, such as investment, interest rates, asset prices and exchange rates. But to fully understand the dynamics of these equations the parameters of the systems must be known. Sometimes equations can be solved to give the most likely values for parameters such as the mean or volatility. But, for the most interesting examples, this method does not work. In practice, parameters must be estimated from historical observations of the variables.
Dr Jun Yu, from The University of Auckland, received a Fast-Start Marsden
grant in 2001 to focus on finding a better method of estimating such parameters.
Dr
Yu, one of the first 20 to receive the grants for emerging researchers, said
the support was invaluable in allowing him to get feedback, visit collaborators,
and concentrate on research.
In previous work, in collaboration with Drs Renate Meyer and Andreas Berg from the Department of Statistics at The University of Auckland, Dr Yu focused on a simulation-based method for estimating parameters. These simulations sometimes took several days to complete, but the method produced very precise estimates of the parameters.
The latest work by Dr Yu, published in the Econometrics Journal, details a new method that instead involves transforming the equations to simplify their processing. Conceived in collaboration with Professor Peter Phillips, from Yale University and The University of Auckland, the method samples data in an irregular manner, with the time between samples depending on the value of the previous sample. By taking some artificial data, the pair proved that their method offered an improvement over those proposed in earlier literature. The researchers then took two real datasets US and British interest rates where only points that are sampled are known, and compared their method with existing ones. While they found that the results for British interest rates were similar, the long run mean they found for US interest rates was 19% lower than previous estimates.
Such large revisions have important implications for financial predictions such as option pricing, where one party purchases the right to buy shares from another for a fixed price at a specified date. Both parties are betting they understand the fluctuations of the market better than the other. With Dr Yu's new method, one of them may be right.
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For further information, contact
Dr Jun Yu Department of Economics The University of Auckland Private Bag 92019, Auckland Tel: (09) 373 7599 ext. 85770 Email: j.yu@auckland.ac.nz |
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| The Otago group has determined the structures of large cyclic complexes with two cobalt ions with different axially coordinated molecular groups (A). |
The computers of the future will be energy efficient, fast, and powerful as well as small. But such advances will require appropriately tiny molecular components.
Associate Professor Sally Brooker's group in the Chemistry Department at the University of Otago is attempting to construct molecules that can act as both switches and memory devices, two key components of any computer.
An electron can be thought of as a spinning ball of charge which creates a magnetic field. Most electrons in an atom pair up so that opposite spins cancel out, giving zero magnetic field, but some outlying electrons do not. For example, in the magnetic metal ion cobalt(II) there is always a net spin. But when this ion is incorporated into molecules two states are possible: mostly paired up, low-spin ("off"), and mostly unpaired, high-spin ("on").
The Otago team, which has included stints from Drs Udo Beckmann, Carsten Brandt, Duncan de Geest, and Katie Heslop, as well as from Janna Ewing and Simon Iremonger, is taking advantage of the ability of metal atoms in certain molecules to switch between these two magnetic states the so-called spin-crossover phenomenon. There are a number of ways this can be induced; the Otago researchers are concentrating on pushing the molecules from one state to another through changes in temperature.
For a practical nanoswitch, this thermal crossover must occur at, or close to, room temperature and be complete over a small temperature range. The Otago team has reported, in Angewandte Chemie International Edition, a large cyclic molecule containing two cobalt ions that exhibits spin crossover encouragingly close to room temperature.
This molecule was the first cobalt complex to show spin crossover as well as interactions between the cobalt ions. Now the Otago team has fine-tuned its properties by varying the molecular groups bound to the metal centres. Altering these, the group reported in Dalton Transactions last year, can change the state of the molecule from "on" to "off" or can induce switching between the two states with a change in temperature. Next they aim to add iron to their molecules, in an attempt to bring down the temperature range over which spin crossover occurs.
When suitable molecules pack together, the interactions between the molecules can become strong enough that all the molecules act together spin crossover becomes a cooperative phenomenon. This makes the crossover occur over a narrower temperature range, helping to create an ideal switch. It also helps the crossover to show hysteresis where the system takes a different path from spin-down to spin-up to that taken in the opposite direction, displaying memory of the state it was in before. Achieving this type of behaviour by stacking these molecules is a goal of this research.
In an unexpected sideline, one of the new generation of dicobalt molecules, in which the large organic cyclic molecule surrounding the metal ions has been modified, has shown unusual reactivity and created a compound with features also found in vitamin B12. The B12 in our bodies is essential as a catalyst for many reactions; the Otago team's new molecule could potentially catalyse important chemical transformations too.
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For further information, contact
Dr Udo Beckmann or Associate Professor Sally Brooker Department of Chemistry University of Otago P.O. Box 56, Dunedin Tel: (03) 479 7919 (SB) Email: sbrooker@alkali.otago.ac.nz |
What happens when the left and right hemispheres of your brain can no longer communicate? Medical science found out when an operation to cut the corpus callosum, a thick bundle of nerves that connects the two hemispheres, first took place in the 1960s. Severing this neuron highway brought relief for drug-resistant epilepsy, by preventing seizures from spreading throughout the brain. But that relief came with a range of interesting and odd effects.
Researchers soon discovered that the visual world of these patients was essentially split in half. Patients who saw an image on their left side, so that their right brain processed the information, were unable to name what they had seen, and sometimes even said they had seen nothing at all. The right brain, at least immediately after the operation, seemed to be both mute and illiterate.
The idea that different sides of the brain control different types of thoughts has taken hold in popular culture and spawned entire shelves of self-help books on the subject. But it seems the world of such people is not completely split. Marsden-funded work at The University of Auckland has shown that while split-brained people cannot match simple colours or shapes on opposite sides of space, they can integrate certain kinds of information. They can judge whether sloping lines on the two sides are aligned, and decide whether a dot that appears on one side, and then the other, jumps to the left or the right. Split-brained people also, remarkably, seem to have little difficulty avoiding collisions while navigating the real world.
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But the valuable insights that split-brained people provide into the different functions of the two sides of our brain are becoming rare. Improvements in the control of epilepsy mean operations to cut the corpus callosum are mostly unnecessary. There are, however, a few split-brained people still available world-wide, and Professor Michael Corballis from The University of Auckland recently met with a split-brained man in Italy to gain some insight into these phenomena.
The man was asked to indicate on a keyboard whether pairs of colours were the same or different. When the colours were from opposite sides of space he responded at a chance level, as expected. When the colours were both on the right, the man gave perfect responses. But when they appeared on the left, he failed to respond at all. He could not even respond to a single flash of light on the left by pressing a key. As in the earlier experiments where there has been a lack of verbal response, it was as though his right brain had simply closed down. However, the Italian man could easily point to a flash of light on the left and even indicate, by pointing, whether the flash was moving up or down.
Such dissociation between symbolic detection whether verbal or by a keyboard and pointing can be linked to a distinction between two visual systems in the brain. One, called the "what" system, maps from the occipital lobes to the temporal lobes, and has to do with the identification of objects. The other, called the "where" system, maps from the occipital lobes to the parietal lobes, and has to do with the locations of objects. The right side of the Italian man's "what" system seemed to have lost consciousness, but the right side of his "where" system remained intact.
The "where" system, which allows us to navigate through space, is probably more primitive in an evolutionary sense, and probably includes small connecting fibres that are subcortical and more primitive than the corpus callosum. Further testing has suggested that the "where" system may remain largely connected in the Italian split-brained man, as well as in others who have undergone the operation.
The Italian man is unusual among split-brained people in the extent of his neglect of the left side of space, but he has (literally) pointed the way to further experiments that will allow more accurate mapping of these very different components of the visual system.
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For more information, contact
Professor Michael Corballis Department of Psychology The University of Auckland Private Bag 92019, Auckland Tel: (09) 373 7599 ext. 88561 Email: m.corballis@auckland.ac.nz |
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| A 19 million year temperature record for water near the seafloor (shown in black) and surface water (shown in grey) from Site 593 in the southern Tasman Sea. For comparison, the shaded areas show the modern temperature ranges. |
In addition to deducing temperature changes from the core, Professor Cam Nelson and Dr Cooke's work also included an analysis of the sediment grain sizes, which can confirm climate records, and the surprise discovery of bolboforms, rare and enigmatic microfossils that are believed to be related to marine algae (see Marsden Update, July 1999).
The temperature record was found by analysing the calcium-carbonate shells of micro-organisms called foraminifera, which either float on the surface or dwell in the sediment at the bottom of the sea. The ratio of oxygen isotopes in these foraminifera depends on both the temperature and oxygen isotope composition in the sea water in which the foraminifera were living. By measuring the shells' isotope values, and by making reasonable assumptions about the sea water isotope values of the time, the researchers could define separate temperature records for the seafloor and surface waters of the Tasman Sea.
Those temperatures probably had a strong influence on New Zealand's past climate at about 300 km west of the northern South Island on the Challenger Plateau, Deep Sea Drilling Project Site 593 lies directly in the path of the westerly wind systems that so strongly influence New Zealand's weather patterns.
Water on the seafloor at this site originates as surface water in Antarctica and then flows north, sinking when it meets other bodies of water, until it bathes the sloping edge of the undersea Challenger Plateau. Called Antarctic Intermediate Water, it ranges in temperature from about 3.57.5°C (shown in the left-side shaded box of the accompanying diagram). Over the past 19 million years, as the fluctuating black line shows, this water has cooled by up to about 10°C. This fits well with a global increase in ice, principally on Antarctica, but also in the Arctic.
As one of the first long records from intermediate-depth rather than very deep bottom waters, it is significant that this record has picked up the globally recorded ice expansions that very deep waters show. The local effects, which often complicate shallow, near-shore records, have not swamped the intermediate-depth climatic record.
The modern surface water at Site 593 is subtropical water that flows into the Tasman from the northeast, with a temperature range of about 1017°C (right-side shaded box). This water seems to have been consistently warmer 19 million years ago, though there were still fluctuations of several degrees. The later, more extreme fluctuations, in addition to reflecting the well-documented ice volume changes at this time, are partly because some near-surface foraminifera moved to a different depth habitat in the water, altering the temperature of their surroundings.
Importantly, however, the surface water stayed largely within the modern temperature
range over the past 19 million years. This means that cooling was greater at
higher latitudes, the source of the intermediate waters, than it was in the
subtropics, the source of the surface waters the oceans did not cool
uniformly as ice in the Antarctic and Northern Hemisphere increased. Moreover,
this New Zealand record provides an historical guide to natural climatic fluctuations
against which human-induced impacts can be better assessed.
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For more information, contact
Dr Penelope Cooke or Professor Campbell Nelson Department of Earth Sciences University of Waikato Private Bag 3105, Hamilton Tel: (07) 838 4024 ext. 6186 Email: p.cooke@waikato.ac.nz |
Origins of autobiographical memory
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| Patrick Read, 20 months, discovers his reflected self. |
Dr Reese's study, published with PhD student Keryn Harley in the journal Developmental Psychology, provided some evidence for this theory. They found that children who recognised themselves earlier displayed more advanced autobiographical memory skill later on.
But the researchers found that self-recognition is not the only way to gain lasting memories. Some children who had high language skills but had not displayed self-recognition were capable of autobiographical memory. And by the time the children were two, the advantage of early self-recognition had mostly given way to another important factor: the caregiver's style of reminiscing and the closeness of their bond with the child.
It seems that autobiographical memory and the beginning of our life stories as we remember them can be reached by a number of different paths. The message for teachers and parents is to embrace diversity in the way young children develop.
Our inability to remember events from early childhood infantile amnesia has been the subject of numerous theories, studies and court cases over the past decade. The conundrum is that, while very young children show evidence of long-term memory, most adults' earliest memories start after the age of three. What stops our recall of the earlier part of our lives and what factors allow autobiographical memory to begin?
Dr Elaine Reese, and a team based at the University of Otago, have been conducting the first investigation into early autobiographical memory that has measured different influences in the same children over time. Dr Reese has followed children from early in their development (1-1.5 years) to a time when children can competently tell others about their lives (4-5 years old).
One of the main goals of the Marsden-funded programme, in its first three years, was to assess the role of self-understanding in the development of autobiographical memory. To measure this, the researchers tested whether children could recognise themselves in a mirror. They surreptitiously applied face paint onto the child's nose under the guise of wiping it with a tissue. Later, the child
reaction was observed in front of a mirror. Only when the child touched his/her own nose instead of the nose in the mirror had the child shown a concept of their (unmarked) self.
One controversial theory proposes that an early concept of self, measured by the children's ability to recognise themselves in a mirror, is necessary for autobiographical memory. Only then can infants begin to attach memories to a category of self.
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Associate Professor Elaine Reese Department of Psychology Clark University Worcester, MA 01610-1477, USA Tel: (001) 508 793 7271 Email: eReese@clarku.edu |
1.Marsden Fund Council
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Dr Garth Carnaby Wool Research Organisation of New Zealand (Inc)
Professor Rob Ballagh University of Otago
Professor Sally Casswell Massey University
Professor Marston Conder The University of Auckland
Dr Ian Ferguson HortResearch
Mr Jonathan Mane-Wheoki University of Canterbury
Professor Pat Sullivan Massey University
Dr David Wratt National Institute of Water and Atmospheric Research Ltd
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Marsden Update is published quarterly by the Marsden Fund and is available free on request. Editor: Lynley Hargreaves. Email: lynley.hargreaves@rsnz.org