Australasian Science: Australia's authority on science since 1938

Feature

Feature article

A Reproductive Riddle

Scanning electron micrographs of the penis from a fawn hopping mouse (left) and spinifex hopping mouse (right) showing the narrower shaft but much larger spines that enable the spinifex hopping mouse’s penis to lock into place during mating.

Scanning electron micrographs of the penis from a fawn hopping mouse (left) and spinifex hopping mouse (right) showing the narrower shaft but much larger spines that enable the spinifex hopping mouse’s penis to lock into place during mating.

By Bill Breed

They look cute and even like to cuddle, but what do the small testes and spikey penis of the spinifex hopping mouse tell us about their ability to survive and thrive between periods of drought and flooding rain?

Many people will be aware that marsupials and monotremes have been present on the Australian landmass since the breakup of the southern supercontinent, Gondwana, 50 million or more years ago. Less well known is the fact that the first native rodents arrived in Australia from South-East Asia around six million years ago and now make up approximately a quarter of all Australia’s land mammal species.

Bill Breed is a Professor at The University of Adelaide and co-author of Native Mice and Rats (CSIRO Publishing, 2007).

A Reef Too Far?

Goldtail damselfish. Credit: Mary Bonin

Goldtail damselfish. Credit: Mary Bonin

By Mary Bonin, Glenn Almany & Geoff Jones

Coral reefs are being subjected to more disturbances than ever before, but a new study has surprisingly found that reef fish can benefit from habitat fragmentation.

Corals are pretty amazing animals. These tiny creatures are capable of building huge reef structures like the Great Barrier Reef, which is the world’s largest structure created by animals and can be seen from outer space.

Corals are like the trees in a rainforest, providing habitat for the animals that make reefs their home. They are so important to the coral reef fish community that at least 10% of the fish species on the Great Barrier Reef cannot survive without live corals.

Mary Bonin is a postdoctoral researcher in the ARC Centre of Excellence for Coral Reef Studies and the School of Marine and Tropical Biology at James Cook University. Glenn Almany is a Future Fellow in the ARC Centre of Excellence for Coral Reef Studies at JCU. Geoff Jones is a Professor in the School of Marine and Tropical Biology at JCU and a Chief Investigator in the Centre.

Identical Genes, Individual Twins

Photo: Fotostudio Enjoy, Ingrid van Heteren (NL)

Identical twins essentially have the same DNA sequence, but the way they use their DNA can be vastly different. Photo: Fotostudio Enjoy, Ingrid van Heteren (NL)

By Marcel Coolen

Identical twins essentially have the same DNA sequence, but the way they use their DNA can be vastly different. Photo: Fotostudio Enjoy, Ingrid van Heteren (NL)

About once every 80 live births, a twin pair is born. The majority of these twins are fraternal, meaning they are derived from two separate fertilisations and are as similar genetically as brothers or sisters.

The research described here was performed by Dr Marcel Coolen at the Garvan Institute of Medical Research’s Epigenetics group headed by Professor Susan Clark. Dr Coolen is currently group leader at the Department of Human Genetics, Radboud University Nijmegen Medical Centre, The Netherlands.

Enzyme Evolution Reveals Earth’s Inhospitable Past

Photo: Ruth Arcus

Stromatolites found in Kalbarri National Park, Western Australia. Photo: Ruth Arcus

By Joanne Hobbs & Vic Arcus

The reconstruction of a one-billion-year-old enzyme paints a picture of a hot and hostile past.

The difficulty with studying extinct organisms is exactly that – they’re extinct. It is even more difficult to study the first microbes on Earth because, unlike the dinosaurs, they were too small to leave their imprints in the rocks as fossils.

Joanne Hobbs is a postdoctoral research scientist and Vic Arcus is an Associate Professor in the Department of Biological Sciences, University of Waikato, New Zealand.

New Life for Ancient Malaria Remedy

Credit: Paula Bronstein / iStockphoto

A Burmese boy suffering from malaria is held by his mother at a special clinic for malaria. Credit: Paula Bronstein / iStockphoto

By Nick Klonis & Leann Tilley

The parasite responsible for malaria is developing resistance to a frontline drug that was first used in China more than 2000 years ago. By determining how artemisinin works, scientists may have just opened a new battlefront in the war against malaria.

In the 5th century BC, Hippocrates described a sickness that was caused by breathing the air of fetid swamps. The disease became known as malus aria – Latin for “bad air”.

It was not until just over 100 years ago that protozoan parasites were identified as the causative agent of the disease. These deceptively simple single-celled organisms exhibit a very complex lifecycle involving a human and a mosquito.

Nick Klonis is a Senior Research Fellow andr Leann Tilley is a Professor of Biochemistry and Molecular Biology at the Bio21 Institute, The University of Melbourne.

Catch ‘Em Before They Fall

Elderly man falling

Falls-risk assessment is currently a very active research area that is spurred on by the ageing populations in developed nations.

By Stephen Redmond

Biomedical engineers are developing a sensor that can predict when elderly people are going to fall.

One in three Australians aged over 65 years fall each year, and the injuries they suffer cost the Australian healthcare system more than $500 million (and rising) per annum. This ratio increases to one in every two people aged over 80 years, and in this age group injuries due to falls are seven times more numerous than all other causes of injury combined.

However, there is something quite impersonal about these cold hard facts. What is much harder to quantify is the personal cost of falls.

Stephen Redmond is a lecturer in the University of NSW Graduate School of Biomedical Engineering.

Fooling Nemo

Clownfish

Ocean acidification results in behaviour that decreases the odds of survival for reef fish

By Kate Osborne

Clownfish use their sense of smell to warn them of the presence of predators, but the pH conditions expected as a result of climate change fool them into swimming towards impending danger.

Have you ever had the feeling that something is wrong? “The hair on my neck prickled” and “I smelt a rat” are two examples of expressions to describe that feeling. What we perceive as intuition is our sensory system sending messages to our brain.

Kate Osborne is an ecologist and science writer.

Warmer Does Not Mean Drier

CO2 are pumped into a plot that is also warmed by infrared heaters.

Controlled concentrations of CO2 are pumped into a 3-metre diameter plot that is also warmed by infrared heaters overhead.

By Feike Dijkstra

A warmer climate causes grasslands to dry out faster, but a new study has found that more efficient water use by plants in response to rising CO2 concentrations in the atmosphere could completely offset the drying effect caused by warming.

Global temperatures are on the rise as a result of increased greenhouse gas emissions into the atmosphere. To cope with the warmer temperatures, plants transpire more water to help them cool off. As a result, terrestrial eco­systems use more water and dry out faster.

Feike Dijkstra is a Senior Lecturer in Biogeochemistry in the Faculty of Agriculture, Food and Natural Resources at the University of Sydney. He is a research collaborator of the Prairie Heating and CO2 Enrichment experiment in Wyoming, USA.

Masters of Disguise

A fairy-wren feeds a hungry Horsfield’s bronze-cuckoo fledgling.

A fairy-wren feeds a hungry Horsfield’s bronze-cuckoo fledgling.

By Naomi Langmore

To avoid rejection by their hosts, Australian bronze-cuckoo chicks are near-perfect visual and vocal mimics that can quickly modify their call to match the species they are parasitising.

For millenia, Australia’s bronze-cuckoos have tricked other birds into rearing their young. The female cuckoo quietly removes a single egg from the nest of the host and replaces it with one of her own, and the unsuspecting host incubates the egg along with her own clutch.

Naomi Langmore is an Australian Research Fellow in the Research School of Biology at the Australian National University.

Smell & Taste Disorders in Children

Smell and taste disorders compromise the health of children.

Smell and taste disorders compromise the nutritional health of a significant proportion of young Australians.

By David Laing

The rate of taste disorders in children exceeds World Health Organisation guidelines, and combined with smell disorders compromises the nutritional health of a significant proportion of young Australians.

If you have a poor sense of smell you will not detect the presence of leaking gas in the home or service station, or the smell of other poisonous gases like chlorine and the foul-smelling rotten egg gas, which can be emitted at dangerous levels from swamp lands or marshes.

David Laing is an Emeritus Professor and Conjoint Professor at the School of Women’s and Children’s Health, University of NSW and Sydney Children’s Hospital.