reproduction

Why don’t elephants (and humans) have thousands of little babies instead of one big one?

Sydney researchers have discovered and modelled the key factors responsible for offspring and family size.

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Studies by University of Adelaide doctoral student Cadence Minge have shown that a high fat diet can cause damage to eggs in ovaries. And when fertilised, these eggs do not develop into normal, healthy embryos.

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Edwina Sutton and colleagues at the University of Adelaide have been busily turning female mice into males.

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Australian orchids are engaged in an arms race, using sensory overload to seduce male insects.

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How sea slugs fall in love

14 August 2007

in 2007

Scott Cummins and his colleagues at The University of Queensland have uncovered a potent mix of chemicals which acts like a cross between Chanel No 5 and Viagra-but only if you are a sea slug.

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A young Melbourne researcher has discovered that a compound
which attracts white blood cells to areas of inflammation also plays an
important role in attracting human embryos to the womb, supporting the establishment of a healthy pregnancy.

Approximately 1 in 6 Australian couples will experience infertility. A large part of this may be due to faulty coordination and guidance of the embryo to the mother’s womb.

Natalie Hannan, of Prince Henry’s Institute, has found that the compound fractalkine is also produced by the uterus. To ensure a healthy pregnancy, the lining of the uterus must produce factors that attract the embryo to implant and begin to grow. Fractalkine may help the placenta to form and tap into the mother’s blood supply, by guiding the cells from which it develops to their right destination.

“In short, fractalkine plays an important role in the establishment of a healthy pregnancy,”  says Hannan of the Uterine Biology Group at Prince Henry’s whose work led to the unravelling of the compound’s role.

“The problem for many infertile couples lies in failure of the embryo to become properly embedded in the mother’s womb. A better understanding of this complicated process should advance treatments for infertility.

“Although infertility treatment has dramatically improved over the past few years, more than 75 per cent of in vitro fertilisation (IVF) attempts will fail. A large part of this may be due to faulty communication between the mother and the baby, involving compounds such as fractalkine.”

Hannan says that fractalkine is produced by the lining of the uterus at the time of implantation, when the embryo makes a special receptor that enables it to respond to fractalkine.

Using advanced technology that allows the movement of cells to be measured, Hannan discovered that human placental cells migrate towards fractalkine. Without fractalkine and many other similar compounds involved in the control of the essential processes of early pregnancy, implantation will fail.

“This exciting finding may improve IVF success rates by providing new targets for infertility treatment. It also aids our understanding of what makes a healthy pregnancy, which is ultimately a successful start to life,” Hannan says.

Natalie Hannan is one of 16 Fresh Scientists who are presenting their research to school students and the general public for the first time thanks to Fresh Science, a national program hosted by the Melbourne Museum and sponsored by the Federal and Victorian governments, New Scientist, The Australian and Quantum Communications Victoria.  One of the Fresh Scientists will win a trip to the UK courtesy of the British Council to present his or her work to the Royal Institution.

Playing possum: one love

10 August 2006

in 2006

Why are some males faithful, stay-at-home partners while others sleep around, with no strings attached? In mountain brushtail possums, it turns out to depend on how disturbed their home is.

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Frog sex in the city

31 August 2004

in 2004

Tree frogs defy the trend of urban decline

Central Melbourne used to be a Mecca for frogs, but now there is only one species left.

Southern brown tree frogs can still be heard calling to attract females for mating in parks throughout inner Melbourne, including the Royal Botanic Gardens and Fitzroy Gardens.

A survey conducted at 104 ponds across Melbourne found a total of nine frog species, but revealed the southern brown tree frog to be the sole inner-city survivor.

An important factor in the loss of other frog species from central Melbourne is the steep walls of bluestone or concrete surrounding many ponds, according to Dr Kirsten Parris of Deakin University and the Royal Botanic Gardens Melbourne.

“Most frogs around Melbourne can’t climb vertical surfaces, so young frogs would become trapped in these ponds and drown,” Kirsten said.  “But the southern brown tree frog can climb, using its large sticky toes – that’s what makes this frog special.”

A second reason for the decline of frogs in the city is that urban ponds are isolated from each other by roads, houses and factories.  If a population dies out, other frogs cannot arrive safely to start a new population.

“Frogs cannot cross busy roads without being squashed.  I found that the number of frog species at a pond drops as the number of roads around the pond increases” Dr Parris said.

“There are two simple things we can do to bring more frogs back to central Melbourne – replace steep pond walls with gradual slopes, and use a carefully-designed program to reintroduce the tadpoles of some species that used to live there.

“This way, late-night revellers in the city will be able to hear a varied chorus of frisky male frogs calling to woo their women and perpetuate the species in an unlikely urban habitat.”

Kirsten is one of 15 early-career scientists presenting their work to the public and media as part of Fresh Science 2004. The scientist who best meets the requirements of the program will win a study tour to the UK courtesy of British Council Australia.

     
  The southern brown tree frog, showing the large sticky toes that enable it to climb.  Photo: Nick Clemann  
  The southern brown tree frog, an urban survivor.  Photo: Nick Clemann  
 
A pond in the Carlton Gardens, surrounded by a bluestone wall.  This pond is home to the southern brown tree frog.

Puberty blues: goby fish choose their sex to find a mate

New research on the Great Barrier Reef has revealed that some young reef fish can choose when they mature and which sex they want to be when they grow up. [click to continue…]

In a world-first, research has used sophisticated time-lapse video microscope techniques to watch the sex lives of red seaweed in action.

“Until now, no one knew what exactly happens when these seaweeds become sexy,” says University of Melbourne researcher, Dr Sarah Wilson.

“Despite the fact that red seaweed is worth hundreds of millions of dollars in the food processing industry for nori (sushi) and also to helps thicken foods like icecream, little is known about them,” she says. “Their reproductive biology has been studied for over a century, but mostly on dried or preserved seaweed.

“This is the first time we have observed their sex life in living cells.”

Dr Wilson will describe the discovery with the help of video footage at a Fresh Science media conference at the Melbourne Museum today (August 18).

“We found that some male red seaweeds will release millions of sperm when there is less salt in the water and at high tide,” Dr Wilson says. “The sperm travel on water currents to the female seaweed and attach to tiny hairs.  The sperm then inject their DNA into the hairs and fertilise the egg which is found at the base of each hair.”

Dr Wilson describes the first time she saw the sperm enter the female hairs as: “very beautiful – so precise and ordered. And it all happened at the microscope level where most of us never get to see it.

“Heaps of sperm land compete with each other to get to the egg at the bottom of each hair,” she says. “It’s a bit like watching a nightclub scene.”

The southeastern coast of Australia has the largest number of red algae species in the world, and they are found in every type of aquatic environment on earth.

Dr Wilson has won a “Science as Art” prize for the exquisite nature of her microscope photography.

Fresh Science is a national science competition where 16 ‘fresh scientists’ (unpublished in the media) are selected with regard to the quality of their research and their ability to communicate that research.

Photographs and broadcast video footage of the seaweed’s sex life are available.

For photos click here

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More mums can breast feed successfully

First images of the breast in action

Mothers can be concerned that they do not have a letdown when breastfeeding, so their babies cannot get enough milk.  For the first time, Donna Ramsey from The University of Western Australia has used ultrasound to capture moving images of letdown in the breast while a baby is breastfeeding.  The work is helping rewrite the anatomy of the breast.

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Scientists agree: some people are universally gorgeous. Studies in evolutionary biology show that few things are more advantageous to success than being attractive, since good looking individuals leave more offspring than their unattractive contemporaries. [click to continue…]

New insight into the cause of female infertility: a certain hormone, interleukin 11, is absolutely essential for female fertility. [click to continue…]

Stress before birth leads to hypertension in adulthood. Trial in sheep suggest that high blood pressure [click to continue…]