Australasian Science: Australia's authority on science since 1938


By Stephen Luntz

Moving genes, diabetes raises disability risk, the maleness enzyme and more.

No Home for Nemo

Nemo’s descendents may have no alternative to a life in dentists’ fish tanks because aquariums may become the only place where clownfish can thrive. It seems the sea anemones that shelter the colourful fish are on the way out.

“Our study showed that at least seven of the ten anemone species suffer from bleaching when water temperatures get too high,” said Dr Ashley Frisch of the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

“Importantly, we found bleaching of anemones occurring wherever we looked – from the Red Sea and Indian Ocean to the Indo-Australian region and the Pacific. Sometimes it was on a massive scale.”

Like corals, anemones depend on symbiotic algae for much of their food, and these are expelled when the water becomes too warm. Anemones are particularly vulnerable because they are long-lived and slow to reproduce, Frisch reports in PLoS One.

While clownfish are the best known, 27 other species shelter among anemones.

Genes on the Move

Scientists have witnessed plant genes moving around in response to environmental changes. The genes were marked with glowing spots that bunched together when they were turned off.

“The movement of genes within the nucleus, captured here using live imaging, seems to play a role in switching their activity on and off,” said Stefanie Rosa of the UK’s John Innes Centre.

“What is remarkable about this finding is that we saw genes move in response to changes in the environment, and that this movement seems to be involved in genetic control,” said A/Prof Josh Mylne of the University of Queensland’s Institute for Molecular Bioscience.

The team focused on the FLC gene, which controls plant responses to seasonal changes. Cold weather turns FLC off and causes the plant to produce flowers rather than leaves. The congregation of FLC genes as they were turned off was unexpected, leading to publication in Genes & Development.

Eleven New Liverworts

Liverworts are not the most dramatic of plants, and their name doesn’t help them get taken seriously. However, Dr Mark Renner of the Sydney Royal Botanic Garden considers his discovery of 11 new species a significant step in documenting Australia’s biodiversity.

“Liverworts have many important ecological qualities and there is potential for pharmaceutical application,” Renner said. “Along with mosses they contribute to nutrient cycles, provide seed beds for larger plants and are vitally important characteristic components of cloud forests.

“Liverworts are also packed full of organic compounds that show promising biological activity, including antifungal, antimicrobial and muscle-relaxing properties, as well as cytotoxicity against some human tumour cells and antiviral properties, including against HIV. The active chemical compounds occur within ‘oil-bodies’, an unusual cellular structure unique to liverworts.”

Renner took 3 years to make the discoveries using a grant from the Australian Biological Research Study scheme.

Diabetes Raises Disability Risk

A meta-analysis of 26 studies has found that diabetes raises the risk of disability for older adults by at least 50%.

“The reasons why diabetes is associated with physical disability are still unclear, although several mechanisms have been suggested,” said Dr Anna Peters of the Baker IDI Heart and Diabetes Institute. “ It’s possible that the high blood glucose concentrations experienced by people with diabetes might lead to chronic muscle inflammation, eventually resulting in physical disability, and some studies have shown that diabetes is associated with rapid and worsening muscle wasting. The complications associated with diabetes, such as heart disease, stroke and kidney disease, can all result in disability.”

Peters did not distinguish between Type 1 and 2 diabetes, but most of the over-65 cohort investigated in the studies would have suffered from Type 2. Depending on the specific study, disability rates were 50–80% higher among those with diabetes.

Vaccinate Households to Protect Infants

A study of children admitted to Westmead Hospital during the 2008 swine flu pandemic identified three major factors leading to increased rates of admission.

“The biggest risk factor we documented was close contact with other (unvaccinated) young children in the household, contributing to 46% of cases,” said Prof Elizabeth Elliott. “The other significant risk factor was that many children were living with at least one smoker in the household, contributing to 36% of cases.”

Household crowding came third, with sick children coming from households with twice the state average number of residents, according to the study in the Journal of Paediatrics and Child Health.

“Infants under 6 months old are particularly susceptible to severe influenza illness; they have no immunity to the disease and they are ineligible for vaccination,” Elliott said. “Disease and complications in this most vulnerable of groups could be reduced by optimising vaccination rates in the household and minimising exposure to other infected individuals, cigarette smoke and overcrowding.”

A Test for Better ‘Flu Drugs

A tool that will speed up the discovery of new drugs to fight influenza has been unveiled at James Cook University.

“Recently, a new promising compound called nucleozin was shown by several research groups to have potent anti-influenza activity,” said A/Prof Patrick Schaeffer. “This compound acts by a new mode of action that is to aggregate the essential nucleoprotein resulting in viral replication arrest.”

Other compounds may be found to do this even more efficiently, but to identify the most promising candidates millions of slightly different versions will need to be tested.

Schaeffer says a new screening assay using a fluorescent nucleoprotein created by the JCU Supramolecular and Synthetic Biology Group has been published in The Analyst. It will drive a high-throughput screening platform that will be used to examine libraries of compounds from tropical plants and animals.

The Maleness Enzyme

An enzyme has been identified that is necessary for mice, and probably men, to become male. Possession of a Y chromosome alone is not enough. The finding could help explain why some people are born as an “intersex” gender with a mix of male and female biological characteristics.

“Most mammals, including humans and mice, are programmed to develop as females unless a specific Y chromosome gene called Sry is present to trigger male development during embryonic life,” said Prof Peter Koopman of the University of Queensland’s Institute of Molecular Bioscience. “We knew that Sry is responsible for switching on maleness genes, but what we didn’t know is that the DNA containing Sry needs be unwound before the gene can become active.”

The work was published in Science, and Koopman says it “opens our eyes to the enormous amount of activity occurring in every cell to coordinate when where each of our 30,000 genes is active. It is a huge logistical task.”

Pineapple Genome Studied

Despite its commercial importance, the pineapple is a largely unresearched fruit according to Dr Jonni Koia of the University of Queensland’s School of Agriculture and Food Sciences.

Koia has changed that with the first pineapple microarray to identify the genes responsible for ripening and vitamin C production, among other things.

“The demand for new plant-based gene promoters without patent protection is of particular interest among the research and agbiotech community,” said Koia, whose research identified two regions that control gene activity within the pineapple cell.

Five Kiwi Songbird Families

New Zealand’s rich birdlife has been recategorised with the recognition that five families of songbird are endemic to the islands.

DNA analysis has revealed that the yellowhead, whitehead and brown creeper belong in their own family, named the Mohoudiae. “Mohoua were clumped in the same genus for some time,” explained Dr Luis Ortiz-Catedral of Massey University, “but this was done without more stringent evidence”.

The findings were an outgrowth of research on New Zealand cuckoos. “We know very little about the long-tailed cuckoo, which parasitises these three species, laying its eggs in their nests,” said Dr Michael Anderson of Massey University. “This research will help us to understand the evolutionary relationship between this brood parasite and its host species.”

All three species have limited ranges, and the yellowhead is endangered.

Eureka! for Our Guest Editor

The guest editor of the July/August 2013 edition of Australasian Science, Prof Rob Brooks, has won the Australian Museum’s Eureka Prize for Promoting Understanding of Science Research.

Brooks is Professor of Evolution at the University of NSW and has explained his field of research in dozens of radio and print interviews, and took part in a 30 minute TV program and some shorter segments. His award recognised all this work.

“Rob Brooks follows in the footsteps of Stephen J Gould with his stories of the ‘consequences’ of evolution,” said the Director of the Australian Museum, Frank Howarth. “He helps people join the scientific conversation by communicating complex ideas without dumbing them down.”