ARDR SCIENCE

Linking Australian Science, Technology and Business
A publication by ELWINMEDIA providing independent information on current developments in the Australian Innovation System

Defrosting discovery

14 February 2014 - Under predicted climate change scenarios, permafrost ecosystems will increasingly transition to wetlands.
Swedish permafrost and Archeae order Methanocellales
Click image to enlarge
Left: Thawing permafrost near Abisko in northern Sweden. Right: the new microbe with the proposed name Methanoflorens stordalenmirensis represents a new family within the order Methanocellales.
image: Wikipedia

This will expose new sources of previously inaccessible organic matter to microbial degradation and ultimately, organic carbon will be converted into CO2. As previously fixed greenhouse gas is released into the atmosphere, the process presents a potential positive feedback to climate change.

The microbial decomposition of organic carbon may also set free methane, a 25 times more potent greenhouse gas than CO2. However, what role methane producing microbes or 'methanogens' may play in a changing climate is not well understodd.

A recent study led by the University of Queensland's Australian Centre for Ecogenomics discovered that in northern Sweden mires with thawing permafrost are dominated by a single type of unicellular methanogen. As detailed in a paper in Nature Communications, the microbe produces methane from CO2 and hydrogen, which it sources from other micro-organisms involved in the degradation of carbon.

The previously unknown organism belongs to the Archaea, a third domain of life that is distinct to Bacteria and Eukaryota, and whose members often live in harsh environments. And within this kingdom of single-celled microorgansims, the new species was found to closely relate to the order Methanocellales, of which one member has been described as a major cause of methane emissions in rice paddy fields.

However, based on a near complete genomic analysis and DNA database comparisons, the researchers propose their discovery to be the first representative of a new family of microorganisms, the Methanoflorentaceae.

And because its members and their close relatives appear to be globally distributed across distant arctic ecosystems and other locations, including temperate, subtropical and marine habitats, Methanofloentaceae could become major contributors to a positive climate change feedback.

More information: www.uq.edu.au

Tested saviour

05 March 2014 - Human Papillomavirus (HPV) vaccination in a 'real world' setting has significantly reduced the frequency of abnormal Pap test results and precancers in women.
Human Papilloma Virus - Cervical Cancer
The image depicts HPV (left) and a cancerous cervix viewed through a speculum.
Image: modified from sketches from NIH/ADAMS.

This is the conclusion of a study which for the first time has analysed Queensland Health datasets and linked the available records from the national immunisation program and the Queensland Pap Smear Register (PSR).

Published in the British Medical Journal by scientists from the University of Queensland and the Queensland Institute of Medical Research (QIMR), the research covers the first four years of the Australian HPV vaccination program, which started in 2007 and was at the time a world-first.

Now similar prophylactic programs have been implemented in over 40 countries.

HPV is a common sexually transmitted infection associated with cancer, notably cervical cancer, and disease. It affects both males and females.

Various types of the virus are implicated in almost all cases of cervical cancer, which originates in the cervix uteri with vaginal bleeding a common first symptom.

Abnormal changes in the cervix that may indicate the cancer is developing can be detected in Pap smears.

The two HPV vaccines currently available cover up to four 'high-risk' types of virus, and hence are not completely eliminating the risk of cancer-causing HPV infections.

In line with previous clinical trials under controlled settings, in the broader population study vaccinated women had a 46% lower risk of developing 'high-grade' changes in the cervix compared to women who had not been vaccinated. And the protection was found highest in women who were not infected with HPV at the time of the vaccination as the vaccine appears not to impact on already existing infections.

The HPV vaccine used in Australia was developed under the leadership of UQ Professor Ian Frazer. Referred to as 'quadrivalent' it targets four of the 'high-risk' types of HPV (6,11,16 and 18). It is marketed as Gardasil by CSL and is now also available for the protection of boys against genital warts.

More information: www.uq.edu.au

A gutful of love

A modified version of the hormone oxytocin may be effective in treating abdominal pain in conditions such as irritable bowel syndrome (IBS).

Oxytocin has been the first synthetically produced peptide hormone and since it is in use for the induction of labour in pregnant women and for stimulating lactation in nursing mothers. But the hormone has a remarkable spread of functions. For example, it is believed to be important for complex social interactions, such as maternal behaviour, partnership and social bonding, and some refer to it as the 'love drug'.

Oxytocin administered intravenously is also known to increase the threshold for abdominal pain. However, the instability of peptide drugs in the digestive system has so far hampered the clinical development as a treatment of chronic abdominal pain, for which there is currently no effective medication available.

In January, scientists from Queensland and Adelaide universities reported in Nature Communictions a new version of oxytocin. Produced through a new strategy they call 'chemoselective selenide macrocylization', the synthetic analogue proved to be more stabile yet just as effective as oxytocin.

They also show that the analgesic properties of the hormone are indeed conferred locally in the gut by acting on so called primary sensory DRG neurons, rather than centrally in the nervous system. The DRG neuron were found to produce high levels of oxytocin receptor in a mouse model of chronic abdominal pain, while DRG neurons in healthy mice did not show detectable levels of the receptor. The researchers speculate that this could minimise potential side effects in a clinical application.

So far, the oxytocin analogue has only been studied in mice but the researchers are now looking for commercial partners to advance the compound into a clinical stage.

More information: www.uq.edu.au

Submerged ventilation

12 March 2014 - Taxonomically classified as ray-finned fish, the most primitive living bony fish, the polypterids, have retained the ability to breathe air as well as water.

Their lungs bear similarities with those of lobe-finned fish or sarcopterygians, of which living forms include lungfishes and also tetrapods.

Click image to enlarge - image shows Polypterus and (insert) the position of a spiracle.
image sourced from wikipedia (insert: John Long)

However, polypterids have another notable feature - large canals on top of the head that are called spiracles and resemble those found in fossil forms of sarcopterygians. This includes close ancestral relatives of tetrapods, the extinct stem tetrapods.

The function of spiracles in Polypterus species has been a 100-year-old mistery. But now it has been discovered that Polypterus ventilates air mostly through its spiracles rather than the mouth.

And this discovery, published in Nature Communications in March, suggests spiracular air breathing may have been an important strategy as fish evolved into land animals some 400 million years ago.

Professor John Long from Flinders University, a senior author in the paper, and his coworkers in the US write that similar to Polypterus, stem vertebrates were likely to be bimodal, breathing alternatively water or air. And they also lived in shallow freshwater habitats, which often are low in oxygen. There spiracle respiration may have conferred an advantage as the fish requiring to breathe air did not have to lift its head above the water.

Polypterus keeps its eyes submerged while breathing air. But the researchers suggest that later stem tetrapods may have had their eyes above water, perhaps crocodilian-like stalking terrestrial prey at the water-land interface.

More information:www.flinders.edu.au; An extended article by Professor John Long in THE CONVERSATION can be found here

Ageless fixation

Scientists including from the University of Melbourne have overturned a long-held believe that older trees fix carbon less rapidly than younger ones.

In fact, the larger a tree gets, the more it seems to absorb (although with the caveat that with its death it may set much of the carbon free again).

Published in Nature in January and also covered in a Nature News story, the team of 38 international researchers derived their data from new and existing measurements of 673,046 trees across 403 species from tropical, subtropical and temperate regions.

Image: University of Melbourne

The surprising result: in 87% of covered species the rate of gained mass increased with tree mass, and in 97% of species the largest trees gained most of the mass each year. For trees 100 centimetres in trunk diameter, the average rate of mass gain above ground was found to be nearly three times that of the same species at 50 centimetres diameter.

Bigger trees increase the total amount of leaves more rapidly, which outpaces the decline in individual leave productivity. And there is more surface across which wood is deposited. The researchers found that this offets the more rapid growth of younger trees..."at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree."

The important implication of their results is that the rapid growth of large trees may play a disproportionately important role in climate change feedbacks. Thus they found that trees greater than 100 centimetres in diameter made up only 6% of trees in some western USA old-growth forests, yet they contributed 33% of the yearly growth in total forest mass.

More information: http://newsroom.melbourne.edu

Charged hopes

All you need is water and air


Researchers from RMIT University have developed a concept battery with a novel metal hydride electrode that can conduct both protons and electrons.

The 'proton flow battery' only requires a power source and water to charge it, and air for the production of electricity.

The system thus acts both as an electrolyser and a fuel cell.

During a charge inflowing water is split to obtain protons which directly combine with electrons and metal particles to form a solid-state metal hydride. The oxygen produced in the split of the water is set free.

Reversing the process just requires inflow of air to release the stored energy in form of electricity.

Sketch of the proton flow battery concept
Proton flow battery concept; sketch by Elwinmedia

The system is less complex and potentially more efficient than conventional hydrogen-based systems, as it does not require intermediate steps of hydrogen gas production, storage and recovery.

In a paper published in the International Journal of Hydrogen Energy in January, the researchers show that the energy efficiency of the proton flow battery could be as high as a lithium ion battery, while storing more energy per unit mass and volume.

The paper is the first demonstration of an experimental preliminary proof-of-concept of the proton flow battery, which could combine some of the best features of a hydrogen fuel-cell based energy storage and a battery. However, while now shown to be technically feasible, the authors acknowledge that additional research is still needed to enhance both its storage capacity and reversibility

More information: www.rmit.edu.au

... and longer lasting discharge


17 December 2014 - A paper in the December edition of Nature Communications describes an important advance in the efficient fabrication of polymer carbon nanoshperes.

This could be of great interest for a wide range of potential applications such as electrode materials for batteries, photonics, drug delivery and the treatment of water.

mesoporous carbon nanospheres
Mesoporous carbon nanospheres

Dr Jian Liu from Curtin University and researchers from Queensland and Adelaide universities as well as from China report that their technology produces a high surface area porous carbon mateiral, which is spherical or hollow in shape. The synthesis can be fine tuned to deliver particles of a size ranging between 80 and 400 nanometres (nm) and pores of around 3.5 nm (by comparison, the diametre of a human hair is around 100,000 nm).

Producing spheres of below 500 nm has so far been a great challenge. By contrast, their technology is low cost, environmentally friendly and suitable for industrial production, the authors write.

Because of the very high surface area of nanospheres they are ideal adsorbents, a characteristic the researchers exploited to immobilise sulfur. The resulting composite material was then tested as a cathode in Lithium-Sulfur (Li-S) batteries, a common type of rechargeable battery found in portable electronics.

The authors found that these batteries have a high initial discharge capacity and good cyclability from which they conclude that composite nanospheres could be promising for a range of energy storage and conversion applications.

Dr Liu said in a press release from Curtin University that the technology could potentially transform renewable, emission-free electrical devices and vehicles across the globe.

More information: www.curtin.edu.au

Bright move

3 March 2014 - Optical tweezers have been around for a while. In fact, they were first reported in the 70s and since then are used to trap and manipulate small objects using a laser light.
According to a recent review article in Nature Nanotechnology, optical trapping has been successful at the subnanometre scale, where light-matter mechanical coupling enables cooling of atoms, ions and molecules, and the micrometre scale, where the momentum transfer resulting from light scattering can be used for the manipulation of microscopic objects such as cells. However, these techniques are difficult to apply at the intermediate nanoscale range.

While the technology found broad application both in biology and quantum optics at the subnanometre and the micrometre scale, the technology has been difficult to apply at the nanoscale for the manipulation of, for example, nanowires, nanotubes and graphene.

nanotweezer
Nanotweezer: the sketch illustrates a nanoparticle trapped in the bowtie aperture.
Sketch: Macquarie University

A study published in Nature Nanotechnology in March, details a new type of nano-tweezers. It uses plasmonics to trap specimen of just a few tens of nanometres and to diplace them in three dimensions. The invention by Spanish researchers and Macquarie University's Dr Mathieu Juan is based on a mobile optical fiber, which at its end is nano-engineered with a bowtie-like gold aperture.

A major advance of the 'near-field optical nanotweezer' technology is that it operates at very low intensities and thus is compatible with heat-sensitive objects such as biospecimens.

The new technology is also relatively manageable, as the optical fibre is used for both the trapping and monitoring of specimen. Therefore, the tweezer could enable researchers to manipulate nano-objects outside of the physics research lab, for example in a medical research context. Another potential area of application is in materials science, for example for the arrangement of solid-state nano-objects such as nanocrystals.

More information:www.mq.edu.au

... and atomic ejection


05 March 2014 - Light may also brighten up the prospects of creating future nano-scale diamond devices.

The power and precision of light-matter interactions has long been exploited with the use of intense laser beams for detailed cuts or drills at the small scale. But the push towards even higher resolutions for manipulations at the atomic level has been hampered by the very function of the laser beam, the localised transferal of heat onto material, as the heat then readily dissipates into the surrounding area.

The interaction of ultraviolet laser beams with a diamond surface can be confined to the atomic scale for the targeted removal of single atoms.
Image: Chris Baldwin

There are examples for atom-scale manipulations, though, such as the use of sharp tips in scanning probe microscopy. However, these methods are not suited for many materials, such as silicon and carbon crystals, where the atoms are tightly arranged in a regular lattice and bound to each other through fixed chemical bonds, also called covalent bonds.

In a paper in a March edition of Nature Communications, Macquarie University researchers describe a discovery that pulsed beams of ultraviolet lasers can resonate with covalent bonds holding together the carbon atoms in diamond crystals. And they show that it takes the energy of two photons for targeted breaks that remove single atoms from the diamond surface, etching nano-structures of around 20 nanometres into the diamond surface.

Importantly, the process does not generate significant local heat.

Associate Professor Richard Mildren and coworkers write that the finding of a coupling between the light field and localised bonds is of fundamental importance for developing optical tools that allow bond-specific manipulation in covalent materials. "This may provide a pathway forward for engineering diamond devices that benefit from increased resolution such as low-loss waveguides, quantum devices, high-speed electronics and high-density data storage".

More information: wwww.mq.edu.au

...and perplexing multiplexing


Multiplexing generally refers to methods by which a multitude of distinct messages or bits of information are simultaneously processed.

For example, in telecommunications the term is understood as a process where several message signals or data streams are combined and sent as one signal over a shared medium.

In many other areas of research and technology, multiplexing describes the simultaneous analysis of multiple targets in one sample. And for this type of analysis, optical methods have emerged as powerful tools with applications including data storage, security printing of banknotes, identity cards, trademark tags, high-throughput biotechnology assays and applications in the new field of personalised medicine.

nanoprobes with luminescence lifetime dimension
An artist's impression of the lifetime concept
Image: Macquarie University

Typically, these approaches require a matrix of optical codes that can be accurately identified at high speed. Researchers often use fluorescent markers because they can be easily detected and measured in intensity, but the number of fluorescent colour combinations that can be simultaneously distinguished in a sample is limited because of potential spectral overlaps.

Macquarie University researchers have invented a new concept that adds a temporal aspect to multiplexing. In a paper in Nature Photonics lead authors Yiqing Lu and Dr Dayong Jin and coworkers write that this lays the foundation for future libraries of nano-/microprobes that may carry more than 10,000 distinguishable codes based on combinations of colour, intensity and lifetime of signal. The new dimension is provided by luminescent nanotags or microcarriers. These are based on populations of rare-earth doped nanocrystals, or 'T-Dots', that display a distinct lifetime of luminescent signal.

The researchers were able to precisely tune the luminescence decays in a range of micro to milliseconds. Thus coded in the time dimension, in addition to colours, the luminescence lifetimes (T) can be engineered and assigned to a single nanoparticle.

The technology is particularly promising for areas that require the detection of rare events in complex environments, such as biological systems, with potential applications ranging from non-invasive cancer diagnostic kits, rapid pathogen screening tests for acute infections to the invisible coding of authentic pharmaceuticals.

More information: www.mq.edu.au

Money makes the world go right

Just in case you wondered or needed confirmation, having earthly possessions does seem to change your view on the world.

A Warwick Economic Research Paper released in February covers a longitudinal study which explored changes in the voting behaviour of thousands of UK citizens after they won up to around 200,000 in the lottery ($370,000).

Money and voting

The finding: winning even a few thousand pounds in the lottery had a measurable effect on 'right-wingness', and the effect was far stronger for males than females.

University of Melbourne Professor Nattavudh Powdthavee co-authored the paper, which still lacks data on individuals winning greater amounts. But he already draws the conclusion that based on the empirical evidence voting choices are made out of self-interest.

And his coworker, Professor Andrew Oswald from the University of Warwick noted in a university statement that "in the voting booth, monetary self-interest casts a long shadow, despite people’s protestations that there are intellectual reasons for voting for low tax rates."

Tenderly explosive beginning

27 February 2014 - At the beginning of the universe, supernova explosions that led to the second generation of stars were of surprisingly low-energy and resulted from first generation of stars prior that were smaller than hitherto assumed.

A five year search for ancient stars with the ANU SkyMapper telescope at the Siding Spring Observatory has identified a star, which based on its apparent lack of iron is over 13 billion years old and may be the oldest known star to date.

Left: SMSS 0313-6708, around 6,000 km from Earth; right: ANU Skymapper at the Siding Spring Observatory
image of SMSS - Dr Stefan Keller, ANU; Skymapper - ANU

The work was led by scientists from the Australian National University and published in Nature in February.

Officially named SMSS 0313-6708, the star complements four other recently discovered stars of low-mass and extemely low 'metallicity' - a term that refers to a relative paucity in elements heavier than helium.

It is believed that the metallicity of a star indicates its age as shortly after the Big Bang the universe contained mainly hydrogen and helium. Heavier elements were then formed in a process referred to as 'supernova nucleosynthesis', in which the first stars evolved and eventually exploded as supernovas. Relatively young stars, such as the Sun, are mostly made up of hydrogen and helium, but also contain oxygen, carbon and nitrogen, as well as large amounts of iron.

By contrast, SMSS 0313-6708 was found to contain traces of lighter elements, including carbon, magenesium and calcium, but no detectable iron. The scientists revealed that its formation was seeded by a single supernova event, which originated from a primordial first-generation star with a mass just around 60 times that of the Sun.

Because of the relatively low energy of the supernova event, almost all the heavier elements were consumed by a black hole that formed at the centre of the explosion.

This contradicts previous assumptions that the first generation stars were extemely massive, with masses hundreds of times that of the Sun, and died in violent supernova explosions that ejected large amounts of iron into the universe.

The now five known low-metallicity second-generation stars provide unique chemical signatures that reveal clues about the generation of stars that preceded them, including that their mass was between 10 and 70 times that of the Sun.

The study also suggests that calcium, previously thought to have formed alongside iron, is not made in supernova explosions but in a very hight temperature hydrogen-burning phase of initially metal-free first stars.

Hence, as Monash University's Professor Alexander Heger observed in a university statement, some of the calcium in our teeth can be traced back to the first stars, and is older than any piece of gold or iron.

More information: www.monash.edu.au

...and black beauty

28 February 2014 - In related research, Australian researchers from ICRAR* and American astronomers have provided the first detailed empirical confirmation of a super-powered black hole.

In a paper in Science they describe a new small but extremely powerful black hole, named MQ1, which they discovered as part of a comprehensive study of the nearby galaxy M83.

MQ1 is a microquasar with a rotating black hole at its center that pulls mass from a nearby companion star. The researchers were able to determine that the mass of the black hole is less than 100 times the mass of the Sun. Yet the energy MQ1 exports would suggest a far bigger size, based on the so called Eddington limit, a rule that sets a certain cap on how much energy a black hole of a given mass can eject into its surroundings.

Image: sourced from an ICRAR media release. Credit J. Miller-Jones (ICRAR) using software created by R. Hynes.

Black holes, such as quasars, are among the most luminous objects in the universe, although this may appear counterintuitive since their mass is understood to be so dense that even light cannot escape.

But when a rapidly rotating black hole pulls in matter from its surrounding, a process astrophysicists refer to as accretion, the particles will not directly hit the centre of gravity. Instead, they feed into an extremely hot 'accretion disk' around the black hole. This chaotic mess of fast moving and colliding particles generates enormous heat and releases 'gravitational potential energy' in form of radiation.

The brightness of a black hole is constraint by the Eddington limit because the outward pressure of the radiation will eventually block the inflow of surrounding matter.

But some accreting black holes, such as the microquasar MQ1, also release energy through jets that shoot out plasma along the axis of the black hole's spin rotation (a paper by ICRAR researchers on these jets was published in Nature in November 2013.)

The MQ1 black hole is only around 100 kilometres wide but its extended jets were found to reach about 20 light years from either side of the black hole. And the researchers determined that for around 2 104 years the mechanical power of the shooting out plasma averaged 3 1040 erg per second, which is much higher than MQ1's calculated Eddington luminosity.

The authors write that the existence of such super-Eddington mechanical power is important for the modelling of jets. Their results would also imply that the influence of super-powered black holes on the evolution of their host galaxy were greater than previously thought.

More information: www.curtin.edu.au; *The International Centre for Radio Astronomy Research (ICRAR) is a joint venture between Curtin University and The University of Western Australia.

Malignant targets

Australia's strength in cancer research has recently been highlighted with a series of high-profile publications.

Together, the papers also show the spread of progress in this area, and the increasing importance placed on promoting the body's own defense capacity.


Regulated kill


24 March 2014 - The most recent study, published in Nature Immunology in March, identified a key protein on the surface of Natural Killer (NK) cells that inhibits the body's own capacity of controlling the spread of cancer.

Natural Killer cells play a crucial role in the early defence against infections and the battle against tumor growth and metastases.

NK-cell-tumour-cell interaction
Sketch: Elwinmedia

Their activity and function, which includes the release of the immune modulator interferon-gamma, is regulated through a series of receptors on the cell surface. Members of the immunoglobulin superfamily are pivotal in this process, of which two proteins, known as CD96 and CD226, were the focus of the research led by the Peter McCallum Cancer Centre and the QIMR Berghofer Medical Research Institute.

The researchers found that CD96 inhibits the production of interferon-gamma and this counteracts the function of CD226, which is known to promote the production of interferon-gamma and thus the killing and control of a wide range of tumors.

So far, the research has been constrained to experiments in mice. This includes animals experimentally made deficient of CD96, which were found to be more resistant to induced carcinomas and metastases than mice expressing CD96.

But the authors conclude that the targeted blocking of CD96, which they describe as a "critical regulator of CD226-dependent antitumor functions", may open a pathway to stimulate the body's own defence against cancer.

More information: www.qimr.edu.au

... with deadly license


20 February 2014 - In a related development, a paper in Nature co-authored by Professor Wally Langdon (University of Western Australia) reports a new inhibitory pathway that could be targeted in order to 'awaken' NK cell's actitivity against cancer metastases.
TAM family - cancer scheme
The above scheme summarises the TAM - Cbl-b interaction and the actions of TAM inhibitors and the Vitamin K antagonist Warfarin.
The figure is a simplified adaptation from a sketch in doi:10.1038/nature12998

The surface of NK cells also contains a set of regulatory proteins that belong to the so called TAM family of tyrosine kinase receptors. These bear important signalling functions for a range of processes such as cell growth and survival and the release of inflammatory cytokines.

The international team of researchers developed a highly selective TAM kinase inhibitor, which administered to mice with experimentally induced cancer improved their ability to control the spread of metastases.

This research was motivated by work on an enzyme called Cbl-b, of which mutated forms have previously been implicated in cancer development. The authors discovered that mice, in which Cbl-b was either genetically deleted or rendered inactive, were able to spontaneously reject metastatic tumours.

Cbl-b is a known E3 ubiquitin ligase, a type of enzyme that tags proteins for their degradation. Its primary target in NK cells were found to be the TAM proteins Tyro3, Axl and Mer, and the researchers were able to show that the direct inhibition of the TAM receptors correlates with the deactivation of the E3 ligase in promoting anti-metastatic activity.

The work thus reveals a new pathway that regulates anti-metastatic activity of NK-cells which could lead to new cancer therapies based on drugs targeting the TAM receptors.

Importantly, mice treated with the TAM inhibitor did not show any signs of side effects such as inflammation or autoimmunity.

The study also solved a 50-year old puzzle about the potential anti-metastatic activity of warfarin, a commonly used bloodthinner that blocks the action of vitamin K. The study found that the mechanism of the anti-cancer activity may involve a direct interaction with TAM receptors and the authors suggest that the use of warfarin or similar vitamin K antagonists in cancer may be re-assessed.

More information www.news.uwa.edu.au

Programmed to die


04 February 2014 - While an essential requesite of animal development, programmed cell death or apoptosis is also a hallmark in cancer.

In the fruit fly Drosophila , a common model organism used in genetics and developmental biology, recent research uncovered a new signal pathway through which the hormone ecdysone controls the precisely timed activation of genes responsible for the removal of the insect's larval salivary glands. And the study by the South Australian Centre for Cancer Biology suggests that a similar hormone-dependent mechanism may also underly some human malignancies.

credit: University of South Australia

An important factor controlling the balance between cell survival and self-destruction are so called histone proteins, which are closely associated with our genome and regulate the activity of clusters of genes.

Histones are extremely conserved proteins in terms of their basic aminoacid sequence. However, certain sites in histones can be chemically modified, such as through 'methylations', and this alters their capacity to bind to DNA.

This 'epigenetic' control of gene activity is facilitated by complex enzymes, which, for example, transfer or remove methylations.

Published in Nature, the research revealed that in the fruit fly a complex enzyme UTX responds to the steroid hormone ecdyson by removing methylations from certain histone sites. In turn, this activates certain genes which, in a precisely timed series of events, leads to the removal of the insect's salivary glands through cellular degradation and apoptosis.

But this finding may be relevant beyond the fruit fly.

A version of UTX is also found in mammalians and is there known to be critical for mammalian embryonic development.

While none of these functions have so far been found to depend on hormones, in some malignancies, including prostate and breast cancers, hormones play a role and the UTX gene has been found to frequently carry mutations.

The authors thus speculate that some of these cancer may involve the UTX enzyme in a steroid hormone-dependent signal pathway.

More information: www.unisa.edu.au
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Click image to enlarge - image shows Polypterus and (insert) the position of a spiracle.
image sourced from wikipedia (insert: John Long)

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Methanoflorens stordalenmirensis in nordic permafrost
Left: Thawing permafrost near Abisko in northern Sweden. Right: the new microbe with the proposed name Methanoflorens stordalenmirensis represents a new family within the order Methanocellales. image: Wikipedia