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By Stephen Luntz

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New Dolphin Species
Victoria’s inshore dolphins have been recognised as a distinct species, bringing the number of bottlenose dolphin types to three. The discovery, published in PLoS One, is a stunning achievement for PhD student Kate Charlton-Robb of Monash University, who combined DNA evidence with skull shape and external characteristics to demonstrate the uniqueness of the dolphins living in Port Phillip Bay and the Gippsland Lakes.

She has named the new species Tursiops australis, with the common name Burrunan. The latter is the word for dolphin in several Aboriginal languages.

“This is an incredibly fascinating discovery as there have only been three new dolphin species formally described and recognised since the late 1800s,” Charlton-Robb says. “What makes this even more exciting is this dolphin species has been living right under our noses, with only two known resident populations living in Port Phillip Bay and the Gippsland Lakes in Victoria.”

Charlton-Robb has been studying dolphins from Bass Strait and Victoria’s bays for13 years. She says: “Previously it had been assumed they were one of the two known species of bottlenose dolphins, truncatus and aduncus, but no one seemed sure which they were.” At different times the Port Phillip Bay dolphins had been listed as each – an understandable confusion since by size they fall between the two widespread species.

In 2003 Charlton-Robb attempted to settle the question, but found that many sections of DNA didn’t match either known species. Molecular analysis suggested separation had occurred 2.6–5million years ago.

Charlton-Robb compared skulls and external features between dolphin populations and found that the Port Phillip Bay population had a more petite skull than truncatus, with certain distinctive patterns. For example, the ratio between the pterygoid and palatine bones is roughly 1:1, whereas among truncatus dolphins it is 2:1.

“The more we looked, the more differences we found,” Charlton-Robb says. The local dolphins can be identified by the lack of a pale shoulder blaze and ventral spotting found among their relatives.

Further study confirmed that dolphins in the Gippsland Lakes are also the new species.

Although the known populations appear to be stable they are extremely small, with just 100 in Port Phillip Bay and 50 in Gippsland.

Specimens from the early 20th century indicate that the same species was living in the Tamar Estuary in northern Tasmania. There have also been reports of what may be Burrunan dolphins in Spencer Gulf.

Charlton-Robb intends to investigate whether other Australian inshore dolphins are in fact T. australis, along with the rate of population interchange between communities. In light of the small populations, mixing would be essential for population health.

“They are subject to many anthropogenic stresses and threats,” says Charlton-Robb. She attends every reported death or stranding of the local dolphins, and tissue samples suggest that mercury concentrations may be a concern. The controversial dredging of Port Phillip Bay has not affected calving or other immediate measures of health, but Charlton-Robb says more long-term effects are being monitored.

Port Phillip Bay has only existed since the end of the last ice age, so the dolphins must have separated from their cousins somewhere else. Charlton-Robb plans to consult geologists to determine whether the waters on either side of the land bridge that now lies beneath Bass Strait would have once made suitable homes for the Burrunan.

DIY Mesothelioma
Mesothelioma cases caused by do-it-yourself renovations are on the rise, and we’re probably well short of the peak, according to research published in the Medical Journal of Australia.

Western Australia has kept track of every case of mesothelioma in the state since 1962. The paper’s co-author, Prof Bill Musk of the University of Western Australia’s School of Population Health, says: “Being a small state we can keep track of the causes of every case”.

Over five decades, 87 cases of mesothelioma have been attributed to home renovations. While the numbers are small they are rising, whereas the number of cases from workers at Wittenoom, where the asbestos was mined, are now stable or in decline. In the past 5 years renovations represented the cause of 13% of diagnosed mesotheliomas.

“Asbestos-containing products such as asbestos cement sheets are still found in many homes, particularly older homes and fences. A recent survey by our colleagues at Curtin University found that many people did not take adequate precaution when dealing with these products,” says lead author Nola Olsen.

Asbestos is only dangerous when airborne and is usually safe when it is not tampered with, although Musk says that fibres can break off asbestos roofs as a result of weathering. The problem arises when renovators break into asbestos walls, often not recognising the material from which they are made.

State regulations require asbestos to be handled by licensed removalists wearing respiratory protection.

Young Star Close to Home
A faint red dwarf, AP Columbae, has been revealed as the closest known very young star.

“For decades it was believed that young stars only resided in vast star-forming regions like the Orion Nebula. These regions are typically several hundred light years away from the Earth. With the advent of accurate all-sky surveys we can now find young stars much closer to home,” says Simon Murphy, a PhD student in the Australian National University’s Research School of Astronomy who was part of the team that determined AP Columbae’s age.

Through a variety of methods AP Columbae’s age has been estimated at 40 million years. Very large stars may live, die and go supernova in that time, but stars as small as this one have far longer life spans than even the sun. AP Columbae is classified as a pre-main sequence characterised by frequent flares and other activity.

By tracking the red dwarf’s apparent movement against more distant stars through the Earth’s orbit, Murphy was able to determine its distance at just 27 light years, comfortably the closest pre-main sequence star.

AP Columbae has an apparent magnitude of 13, which is slightly brighter than Pluto. It forms part of the Argus Association, a group of stars of similar age that are spread over a substantial area of space but are thought to have a common source based on their motion.

Murphy is studying very young stars, and has been examining stars suspected of being very close to Earth in collaboration with a Georgia State University team. Previous studies had identified AP Columbae as a star worthy of further investigation because of its flares. Besides determining its location they studied it at various wavelengths, including in the X-ray band.

Very young, close stars provide an exceptional opportunity to look for planetary systems. Large planets produce substantial amounts of heat through gravitational contraction, particularly when they are very young. With only a faint star nearby, such infrared light should be detectable rather than drowned out.

Finding planets, however, depends on them being there in the first place. “We don’t know much about how planets form around low mass stars, or even if they do,” Murphy says.

Columba, AP Columbae’s astronomical home, is a faint constellation south of Canis Major. While visually unimpressive it contains the solar antapex, the point from which the Sun and Earth are moving away as we circle the galaxy.

Mite Test Predicts Asthma
Toddler sensitivity to house dust mites acts as a powerful predictor of asthma by the age of 12, a study in the Journal of Allergy and Clinical Immunology reports.

Children from families with histories of allergies were tested for sensitivity to six allergens. “We found in the children aged 1–2 years that whatever the mix of sensitivity, if their skin reacted to house dust mites they had a higher chance of developing asthma later in life,” says Dr Carline Lodge of the University of Melbourne.

None of the other allergens were predictive, but 75% of children with a house dust mite sensitivity had asthma by the age of 12, compared with only 36% of those who were negative to dust mite skin prick tests.

“Sensitisation and asthma has been observed a lot,” says Lodge, “but this research is unusual in observing it so early.”

The explanation is unknown. “It could be causal,” Lodge says. “It could be that those who are prone to asthma deal with allergens in a different way.” Exposure to house dust mites is through the lungs, but this is also true of two of the other allergens studied.

Attempts to reduce asthma by controlling dust mite populations or preventative use of corticosteroids have been, in Lodge’s words, “disappointing”. However, she hopes that more success may arise if test programs are able to study more targeted populations.

Less Caffeine Allows Less Sugar
Some of the sugar in colas and energy drinks is only there to cover the taste of caffeine, but a study at Deakin University has found that if caffeine is reduced, the sugar content can also be cut without affecting the taste.

Dr Lynn Riddell of Deakin’s School of Exercise and Nutrition Sciences says that while some people may choose soft drinks for the caffeine, children are unlikely to even know it is there.

Riddell and A/Prof Russell Keast created simulated soft drinks with and without caffeine and with varying sugar contents.

“Using a caffeinated soft drink as a control, we found that when we removed caffeine we could also remove 10% of the sugar before a perceivable difference in the flavour was detected by more than 80% of the tasters,” Keast says. “This shows that caffeine blunts our perception of sweetness, a reason why a large number of people add sugar to their tea or coffee to get the desired flavour.

“The results of this study show that a significant amount of energy in sugar-sweetened drinks can easily be reduced by simply removing the caffeine. More than 80% of the population will not notice a taste difference if the caffeine is removed along with just over 10% of the sugar.”

“If the caffeine and 10.3% of the sugar was removed from soft drinks, we estimate an energy intake reduction of 56 kJ/day for adults and 61.4 kJ/day in children. These calculations are based on the estimated soft drink consumption in the United States,” Riddell says.

She adds that some other soft drinks, such as flavoured mineral waters, might also be able to reduce their sugar content without affecting the taste. However, caffeinated drinks usually contain 3 grams more sugar per 100 mL than other soft drinks.

Ewe Are What Ewe Eat
Farmers may be able to adjust the sex ratio of their lambs by altering the diet they feed ewes, a NSW Department of Primary Industries study suggests.

Charles Sturt University PhD student Catherine Gulliver followed up a research paper reporting that mice fed a diet rich in omega-6 fatty acids produce more female offspring than males. “She approached me about whether we could do such a study in sheep and I helped her set it up,” says Dr Ed Clayton of the DPI.

The pair used 300 ewes with merino dams and border Leicester sires.

The ewes were fed either oat grain high in omega-6 or pea silage rich in omega-3 for 6 weeks before and 3 weeks after being mated. “We identified a 15% increase in the number of female lambs from sheep fed high omega-6 compared with those fed high omega-3 diets,” says Clayton.

“At this stage we can’t be sure the effect applies to other breeds of sheep, but have no reason to think it won’t,” Clayton says.

While reluctant to speculate on a mechanism while a paper on the subject is being peer reviewed, Clayton believes the causes are probably different from those affecting the mice. “The researchers who found the effect in mice think omega-6 may have caused increased uterus inflammation, which had a more detrimental effect on male embryos,” he says. “We think in sheep the effect is pre-conception.”

Clayton bases this conclusion on the fact that there was no reduction in the total number of lambs born on the oat diet, as would be expected if success rates during pregnancy were responsible.

Human consumption of omega-6 has risen dramatically in recent years, particularly in the United States. Clayton says that the mechanism he is working on would “be much more muddy in humans” if it existed at all.

However, he has learned that there has been a slow increase in the proportion of female births in the US in the late 20th century, at the same time as the diet has become heavy in omega-6s.

Gum Genome Sequenced
The genome of the flooded gum Eucalyptus grandis has been sequenced, but the individuals chosen for sequencing came not from the mighty tree’s continent of origin but from vast plantations in Brazil.

Prof Bill Foley of the Australian National University says the flooded gum is the most widely grown forest tree in the world. However, it is not widely grown in Australia because “it grows best in places where people want to live – along the coast”.

In wetter climates the tree is valued for its fast growth, while the chemistry of its wood makes it good for pulping. Pellets from the trees are exported to Europe to feed demand for biofuel.

The sequencing has revealed that the flooded gum’s genome is relatively small at only 600 million base pairs. By comparison the pine tree has 30 million base pairs and people have three million base pairs. However, Foley says the blue gum has an even smaller genome, while certain blood woods have just 55% of the genetic information.

Plantations in Brazil have been devastated by myrtle rust, so most of the crop is now a cloned hybrid of flooded gum and a tropical eucalypt from Timor. Myrtle rust has recently invaded Australia, with devastating effects on some incipient crops, while a strain has emerged in Brazil that even destroys resistant clones. It is hoped the sequencing of the genome will speed the quest to find ways to curtail this blight.

A better understanding of the eucalypt genome could assist commercial development by providing a cash crop that also controls the water table on farms affected by dryland salinity.

Foley also hopes we can learn why a tree that has been in Australia so long has only recently diversified, “with species that grow to 90 metres tall while others are shrubs barely up to the knee. Sequencing is getting cheaper and cheaper, so we want to do more and learn why they are so fire-resistant [and] why the continent is dominated by one single group of trees in a way no other continent is.”

Finally, Foley hopes we will learn how to grow rare species from cuttings, including one from the Canberra region that is now restricted to just three individuals after failed seed propagation efforts.

Krill Migration Fuels Ocean Productivity
Krill sink to depths below 3 km to feed on detritus at the bottom of the ocean, and the iron they bring to the surface may play a crucial role in the marine ecosystem.

Antarctic krill (Euphausia superba) is the only species on the planet with similar biomass to humans, but it has been thought that they are restricted to the top 200 metres of the ocean’s surface. Dr Steve Nicol of the Australian Antarctic Division says that when a British team observed krill at a depth of 3000 metres “people thought ‘that’s unusual’”. However, with the deep ocean relatively unexplored, and the deep Southern Ocean even more so, further investigation was required.

“We began putting together all the observations of krill on the sea floor and discovered there were an awful lot,” Nicol says. “What surprised us was how common these seafloor visits were – we found that around 20% of the population could be migrating at any one time.”

Although no specific experiments have been done to observe krill at these depths, Nicol says that camera operators in a study on the effects of fishing gear off the Antarctic continental shelf complained that at 600 metres they couldn’t see anything for krill. That footage led to the first observations of krill reproducing (AS, May 2011, p.14).

Nicol says that, even for small animals like krill, the migrations are not particularly long. “When they run out of food in an area they have a choice: go 3 km left, or 3 km right, or 3 km down,” he says. “By the time they get back to the surface there may be food again, so it’s a good strategy.”

While some of the krill end up becoming food for bottom-dwelling species, those that return bring with them rich supplies of iron in their stomach. With productivity in 40% of the Southern Ocean limited by iron shortages, krill migration becomes important.

Recent research has demonstrated the importance of whale faeces in keeping the southern ocean rich in iron (AS, July/Aug 2010, p. 7), and Nicol says there is a cumulative contribution. “The more whales there are, the more krill there will be, and the more krill there are the more iron they will bring to the surface.”

Nicol says that a better sampling of krill numbers is necessary to estimate sustainable harvesting rates. “The fact that there is more biomass there than we realised may mean we have been more precautionary in our management than is necessary, but that’s not a bad thing.”

No Love for Cancer Cells
The chemicals responsible for love and death have a common source, at least when the death is one form of cancer.

Oxytocin has achieved fame as the “love hormone”. It is released during labour, breastfeeding and after sex, and is credited with stimulating pair bonding and maternal feelings.

Less well-known is that oxytocin is activated by the enzyme PAM. However, PAM also activates other hormones, including the growth hormone calcitonin.

“Increased levels of calcitonin are correlated with poor survival rates in small-cell lung cancer patients,” says Ms Lucy Cao, a PhD student in the Australian National University’s Centre for Excellence for Free Radical Chemistry and Biotechnology. “Our bodies have feedback mechanisms, so normally calcitonin is released slowly. In cancer cells these feedbacks are broken so the body keeps producing it.”

Cao and her supervisor, Prof Chris Easton, are seeking ways to reduce calcitonin in cancer cells, and investigated whether PAM might be the key. “We were excited to find that a number of our compounds are very effective in reducing the activity of PAM and decreasing calcitonin levels,” Easton says.

If PAM is deactivated, oxytocin levels may be affected along with calcitonin, raising alarming side-effect possibilities. However, Cao says: “So far it appears the enzyme is inhibited only within the cancer cell”.

Cao stresses that more study is required to demonstrate the effects are not more widespread, but if she’s right few would be concerned if cancer cells aren’t feeling the love.

Tooth Loss Higher Among Mentally Ill
Psychiatric patients are more than six times as likely as the general population to have decayed, filled or missing teeth, and are 3.4 times as likely to have lost all their teeth, the British Journal of Psychiatry reports.

Author Prof Steve Kisely of the University of Queensland lays the blame on a range of factors. “People with severe mental illness may not be able to clean their teeth properly because of poor housing or homelessness,” he says. “Some medications such as antidepressants and mood stabilisers can also reduce the flow of saliva and cause dry mouth, which increases plaque formation.”

The cost of treatment is also often a deterrent. The research was done on 2784 people with schizophrenia, dementia, bipolar disorder or other affective disorders. People with some of these conditions may also be particularly frightened of dental treatment.

“Our analysis shows that, although the oral health of the general population has improved in much of the world, psychiatric patients remain at a disadvantage,” Kisely says. “This mirrors findings in other areas such as cardiovascular disease, where the health of the general population has improved – but not that of people with severe mental illness.”

Kisely is not aware of research to quantify the relative significance of factors connecting mental and dental illness, and suspects that “they probably all contribute about equally”.

“The thing to do is to address the easiest ones first,” Kisely says. “When people have contact with the mental health system we often check if they have a GP but not if they have a dentist. It would be relatively easy to add this to the checklist and to try to hook people up with a dentist if not.”

Kisely suggests that case managers should assist patients who may struggle to get to dental hospitals at opening time, which is often a requirement for free treatment.

Poor dental health increases social isolation, making it harder to obtain housing or employment. Moreover, Kisely notes that oral infections have been linked to heart disease.

Past public health programs are reaping some success, however. “Fluoridation definitely improves the position,” Kisely notes. He found that the disparity between the mentally ill and the rest of the population was reduced among those who had drunk fluoridated water as children. “No matter if you are rich or poor you still have access to the same water supply,” he says.

Sulfur Bolsters Plant Defence
Sulfur dioxide preserves fruit by bolstering plant defence mechanisms, the University of Western Australia has found.

Sulfur dioxide was once widely used on fresh produce, but in the 1990s a combination of consumer concerns, acid rain and occupational health and safety factors led the World Health Organization and the Food and Agriculture Organization to ban its use for all fresh fruit other than table grapes.

The exemption was made because grapes are highly susceptible to pathogens, but A/Prof Michael Considine of the School of Plant Biology says: “Even there, in the long term there is increasing pressure with moves towards lower sulfur residues”. Similar forces are at work for dried fruit, wine and jam, all of which are currently still allowed to use sulfur dioxide both before and after harvesting.

Considine hopes that “by improving understanding of how sulfur dioxide works we can mimic the effects with safer alternatives”. He says that his work confirms the idea of sulfur-enhanced defence in plants.

“Sulfur dioxide is a pungent gas and there is irrefutable evidence that it can cause ill-health effects,” Considine says. Nevertheless, sulfur forms an important part of much of the human disease resistance system, as well as that of plants.

“Our findings represent an important milestone, and could provide a turning point in the quest for a safer alternative to sulfites as the research focus shifts to encompass a preservative’s effects on a plant’s innate defences.”

Light Turns Pollution to Alcohol
Sunlight can turn the pollutant acetaldehyde to alcohol in the atmosphere, according to research published in Nature Chemistry.

Acetaldehyde and vinyl alcohol have the same atoms arranged in different combinations. Prof Scott Kable of the University of Sydney says the conversion of one to the other is taught in undergraduate textbooks, but “what was not known is that it can be induced by shining light on acetaldehyde, particularly in the gaseous phase”.

Kable demonstrated this capacity by replacing three of the four hydrogen molecules in acetaldehyde with deuterium. “While not changing any of the chemical or photochemical properties to any significant extent, this subtle chemical change did allow us to follow the photochemical reactions with much more detail,” he says. A tuneable laser was used to test the effect of light at different wavelengths, with the effect strongest in the visible frequencies.

Atmospheric models predicted that acetaldehyde should break into two smaller molecules, but Kable says: “Our experiments showed that the atoms in the molecules were instead extensively scrambling – specifically the hydrogen and deuterium atoms were scrambling – before the acetaldehyde broke apart”.

After initial puzzlement, fellow Sydney University chemist Dr Meredith Jordan provided a theoretical explanation for the observations. The changes can take place with any density of acetaldehyde if the affected molecule has other gas molecules around it to remove the excess energy imparted by the light.

“Our research shows that compounds such as acetaldehyde, when emitted to the atmosphere, will transform into other substances before the sun has a chance to destroy them,” Kable says. “If molecules are being transformed by sunlight, then the chemistry of the atmosphere is much more complicated than we have considered up until now.”

The vinyl alcohol lasts longer in the atmosphere than acetaldehyde, but both eventually break down into the organic pollutants and ozone that form photochemical smog over polluted cities. Kable says neither last long enough to be a problem on a global scale.

However, the discovery does raise the prospect that other substances may experience similar shifts in the presence of sunlight. “We’ve been talking to atmospheric chemists and they want us to test other molecules in the same way,” Kable says. “There are already other people doing similar testing.”

Quantum Particles Behaving Classically
Particles that many physicists thought shouldn’t exist behave in unexpected ways, a collaboration between Macquarie University, the University of Leeds and Microsoft Research has revealed. Such a finding is not unusual in the counter-intuitive world of the very small, but in this case the behaviour of anyon particles is classical rather than quantum.

Anyons are particles that occur only in two-dimensional systems. Initially thought to be a purely mathematical construct, their existence was demonstrated in 2005. “Anyons are not fundamental particles,” explains Macquarie PhD student Mr Lauri Lehman. “When you engineer a system in a particular way you get emergent properties where the excitation levels of the system are localised in space so you can view them as a particle.

“Once the order of the system breaks down they disappear. When you go to very low temperatures and high magnetic fields you can engineer fields so that particles can only move in two dimensions.”

We have become used to extraordinary behaviour in quantum particles, but the surprising thing about anyons is that under certain circumstances these otherwise quantum particles behave classically – that is, like objects we are used to experiencing on human scales. In particular, they move slowly in a manner resembling the random motion of a classical particle.

“This is a surprising result because you would expect anyons to behave like quantum mechanical particles. These are very unconventional properties for this type of particle,” Lehman says. “The explanation is very technical but there is a coherence effect, and once some of the coherence leaks out the anyons slow down.”

Anyons represent one possible route to building quantum computers, but Lehman says the systems he has been working on would not be suited to building full quantum computers. However, the findings may prove useful in distinguishing different types of anyons in ways that may be useful for those trying to put them to work.