Inbox and Environment News: Issue 415

August 4 - 10, 2019: Issue 415

Avalon Dunes Bushcare: Sunday August 4th

This Sunday August 4 We'll be back again, 8.30 - 11.30, meeting on the Yellow Brick Rd near the Montessori School.
We love our Dunes. Our Bushcare group meets on the first Sunday morning of each month to look after them. We remove weeds, plant tubestock sometimes and clear up rubbish.

Wear enclosed shoes, long pants and sleeves, hat and BYO gloves. Morning Tea is provided of course! 

Who remembers when this was happening in the 1950s? Circus elephants grazing on Banksias, near today's skate park.


Sydney Wildlife August 2019 Course

“Goodbye”
It‘s one of the happiest and saddest times of being a wildlife carer. We give the animals a second chance, help them realise their instincts and prepare for the wild. Often we have no idea how they are getting on in their natural habitat after release. We can only hope that the months of dedication and sacrifices pay off.



These two were taken to the vet after being found by members of the public. They were both orphans and soon became close friends in care. Scratchum was found alone in Newtown and Foxy was with her mum (who subsequently died after suspected poisoning) at Fox Studios. Over many months they were bottle fed, introduced to solid foods, increased their strength and climbing skills and now are living in a thick patch of bush in a Sydney suburb.

If you want to become a volunteer carer, rescuer, phone operator, fundraiser or educator, register for the next course to be held 10-11 August in Londonderry. Register here: http://www.sydneywildlife.org.au/upcoming-courses.html

Sydney Wildlife (Sydney Metropolitan Wildlife Services)

Mona Vale Beach Clean

Sunday, August 25, 2019 at 10 AM – 12 PM
Mona Vale Beach,  Mona Vale
Hosted by Northern Beaches Clean Up Crew
Come and join us for our second clean up in Mona Vale. We'll meet at the area between toilet block and cafe as it’s in the middle of area to target. Some can head north through the basin and others south around cafe/ clubhouse and lawn area or down onto main beach. We have gloves, bags and buckets. We'll clean up this area to try and catch all the litter before it enters the ocean. We're trying to remove as much plastic, cigarette butts and rubbish as possible. We're a friendly group of people and everyone is welcome to this family friendly event. It's a nice community - make some new friends and do a good deed for the planet at the same time. 


Fishcare Volunteers Wanted

Have you a passion for helping others, and helping contribute to better fishing and aquatic systems in the future?

Then why not become a FISHCARE volunteer - it's rewarding, a great way to learn and impart skills, meet new friends and have fun, it also allows you to give back to recreational fishing. Currently DPI has 300 Fishcare volunteers across NSW, volunteers assist in teaching others all about fish, sustainable fishing practices as well as the ecosystems fish live in.

The next free Fishcare training weekend is taking place on the 18th of August at Narrabeen, so jump on board and get involved in this fun, social, stewardship based volunteer program. The training weekend encompasses a variety of topics with a focus on Long Reef Aquatic Reserve (including a guided reef walk), and is open to anyone over the age of 18 years of age.

Places are limited in the training a so if you are interested, please get in contact as soon as possible.

For more info: call (02) 9741 4846 or 0417 445 847 or email simone.mabon@dpi.nsw.gov.au

Date: 18 August 2019 
At: Narrabeen, 
Narrabeen Coastal Environment Centre, 
entry via Pelican Path, Lake Park Road, 
North Narrabeen 
Details at: HERE


Spring Fair

Hosted by Stony Range Regional Botanic Garden and Australian Plants Society Northern Beaches Group
Sunday, September 8, 2019 at 9 AM – 5 PM
Stony Range Regional Botanic Garden
810 Pittwater Road, Dee Why 2099
Free

This year the theme is 'Back to the Bush' 
Enjoy native plant sales and advice plus displays, children's activities, live native animals, walks, music, sculptures, photography displays, BBQ  and coffee shop.


Mona Vale Garden Club's 48th Spring Flower Show

Saturday, 28 September 2019 - 10:00am to 3:00pm
Wonderful display of flowers, potted plants, vegetables, herbs and floral art. Plants, white elephant goods and cakes for sale. Raffles. Refreshments available.
Gold coin entry; $2.00 - children no charge
Ted Blackwood Hall
Cnr Jacksons & Boondah Roads
Warriewood


On Chiltern Track- Ingleside

Some wonderful photographs by Pittwater Natural Heritage Association (PNHA) members on the Chiltern Track at Ingleside.



Pods of Acacia terminalis Sunshine Wattle on our favourite Chiltern Track Ingleside. Backlit in the morning.


Amazed to see Honeybees buzzing around flowers on male Allocasuarina distyla., a first for us, and interesting because there’s only pollen on these flowers which flies on the wind to pollinate female flowers on separate bushes.


Prickly Moses Wattle on the Chiltern Track. We just love the sandstone heath understorey.

Repairing Harmful Effects Of Inbreeding Could Save The Iconic Helmeted Honeyeater

August 1, 2019: Monash University
Habitat destruction results in wildlife populations that are small, made up of relatives, and have low genetic variation. Breeding between relatives (inbreeding) has harmful effects called 'inbreeding depression', often experienced as a shortened life, a poor breeder, or even death.

Not surprisingly then, most animals avoid breeding with their relatives. But when populations become too small, it becomes impossible to find a mate who is not some kind of relation.

Research published today in Current Biology by a collaborative research team led by Monash University reveals just how much damage is done by inbreeding in the critically endangered Helmeted Honeyeater.

Professor Paul Sunnucks from Monash University's School of Biological Sciences, who led the study said the findings have wide-ranging implications for wildlife management.

"Our study combines over 30 years of demanding fieldwork and advanced genetics to quantify how much harm is done by inbreeding in the last wild population of the Helmeted Honeyeater, and identifies ways forward," Professor Sunnucks said.

The Monash-led study involved collaboration with Zoos Victoria, the Victorian Department of Environment, Land, Water and Planning (DELWP), and other conservation partners, with funding from the Australian Research Council. The Helmeted Honeyeater, named for its 'helmet' of head feathers, is a much-loved State emblem found only in a small region of the State of Victoria.

Since European settlement of Australia, a staggering 99% of the floodplain forest essential for Helmeted Honeyeaters has been converted to agricultural land and towns. Consequently, only 50 wild Helmeted Honeyeaters remained by 1989. Thanks to conservation actions including captive breeding at Healesville Sanctuary and habitat restoration, there are now about 230 free-living Helmeted Honeyeaters, living precariously in a single location, Yellingbo Nature Conservation Reserve.

The Helmeted Honeyeater would now very likely be extinct if not for those 30 years of conservation actions involving DELWP, Zoos Victoria, Parks Victoria, Melbourne Water, and hundreds of passionate volunteers centred on the Friends of the Helmeted Honeyeater.

"Most Helmeted Honeyeaters over that time have been given coloured leg-bands so that their success in life and love can be followed," said DELWP Senior Ornithologist Bruce Quin, who led the monitoring.

The result is a detailed account of how long each of the birds lived and how many offspring they had in their lifetimes. Combining this information on breeding success with advanced genetic analysis, the research team could quantify the profound damage caused to Helmeted Honeyeaters by inbreeding: the most inbred birds produced only one-tenth as many young as the least inbred.

"Clearly, inbreeding depression is likely to impact the population's chances of survival," said the paper's first author Dr Katherine Harrisson, a Monash PhD graduate now at La Trobe University, and the Arthur Rylah Institute (DELWP).

While inbreeding depression is a big problem, it can be reduced by bringing in 'new blood' from a closely-related population. Such 'gene pool mixing' is an emerging approach to help threatened species. But the wild population of Helmeted Honeyeater is the last of its kind, so where can new genes come from?

Helmeted Honeyeaters are the most distinctive subspecies of the widespread Yellow-tufted honeyeater. In careful trials of gene pool mixing, Zoos Victoria has cross-bred Helmeted Honeyeaters with members of the most similar other subspecies. "Mixing the two subspecies in captivity is going very well, with no signs of genetic or other problems," said Dr Michael Magrath, a Senior Research Manager from Zoos Victoria. "We have plans to release the first out-crossed birds into the wild population at Yellingbo soon," he said.

Professor Sunnucks said that all being well, gene pool mixing could help overcome the burden of inbreeding depression and bolster an enduring recovery of the Helmeted Honeyeater.

Katherine A. Harrisson, Michael J.L. Magrath, Jian D.L. Yen, Alexandra Pavlova, Neil Murray, Bruce Quin, Peter Menkhorst, Kimberly A. Miller, Karina Cartwright, Paul Sunnucks. Lifetime Fitness Costs of Inbreeding and Being Inbred in a Critically Endangered Bird. Current Biology, 2019; DOI: 10.1016/j.cub.2019.06.064


Captively bred Helmeted Honeyeater at the Healesville Sanctuary in Healesville, Victoria,Australia photo by Dylan Sanusi-Goh 

Non-Lethal Impacts Of Seabirds' Plastic Ingestion

July 30, 2019: University of Tasmania
An IMAS-led study of seabirds that had ingested plastic debris has revealed a range of non-lethal impacts on their health and physiology.

While seabird deaths due to swallowing plastic debris or becoming entangled in it have received global attention, the non-lethal effects on seabirds that survive plastic ingestion are less well-known.

The study led by IMAS' Dr Jennifer Lavers and published in the journal Environmental Science & Technology has found that plastic ingestion can have a significant negative impact even on superficially healthy seabirds.

The research, which included scientists from Lord Howe Island Museum and the UK's Natural History Museum, analysed blood and plastic samples collected from Flesh-footed Shearwaters on Lord Howe Island.

"Flesh-footed Shearwaters populations are declining across the south west Pacific Ocean and Western Australia's south coast," Dr Lavers said.

"Plastic ingestion has been implicated in this decline but the mechanisms by which it affects shearwaters are poorly understood.

"Our study found that birds which ingested plastic had reduced blood calcium levels, body mass, wing length, and head and bill length.

"The presence of plastic also had a negative impact on the birds' kidney function, causing a higher concentration of uric acid, as well as on their cholesterol and enzymes."

Dr Lavers said the study found that the simple presence of plastic was enough to cause negative consequences, regardless of the amount.

"Our data did not show a significant relationship between the volume of plastic ingested and the health of individuals, suggesting that any plastic ingestion is sufficient to have an impact.

"Until now there has been scant information on the blood composition of seabirds in the wild, many of which have been identified as threatened species.

"Understanding how individual seabirds are affected is also further complicated by the fact they spend little time on land or at breeding colonies, and most mortalities occur at sea where the causes of death are often unknown.

"The complex range of issues that face seabirds -- from habitat loss and climate change to fishing and marine pollution -- make it vital that we better understand the impact of particular challenges such as plastic debris," Dr Lavers said.

The research was supported by Detached Foundation and Living Ocean Foundation.

Jennifer L. Lavers, Ian Hutton, Alexander L. Bond. Clinical Pathology of Plastic Ingestion in Marine Birds and Relationships with Blood Chemistry. Environmental Science & Technology, 2019; DOI: 10.1021/acs.est.9b02098

Tracking Baby Fish For Better Reef Management

August 1, 2019: ARC Centre of Excellence for Coral Reef Studies
A group of Australian scientists has created the world's first computer model that can accurately predict the movements of baby coral trout across the Great Barrier Reef. The study confirms the importance of fish larvae produced in no-take zones for the health of fish populations within nearby fishing zones.

Tracking the lives of thousands of tiny baby fish is no easy task. But knowing where they'll settle and spend their lives as adults is invaluable data for the fishing industry and reef managers.

The accuracy of the model was tested in a recent study -- led by Dr Michael Bode from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University (JCU) -- that validates the computer predictions with field data.

This is a world-first achievement, combining the movement of ocean currents in and around the Great Barrier Reef with the genetic and behavioural data of fish.

"The study is a unique conservation collaboration between marine biologists, geneticists, and recreational fishers," Dr Bode said.

"This was a major field effort combined with some clever genetic work that involved matching baby fish to their parents to understand their movement," co-author Dr Hugo Harrison, also from Coral CoE at JCU, said. "The behaviour of fish in their first few weeks after hatching can really influence where they eventually settle."

The study focussed on coral trout, Plectropomus maculatus, which is one of the most valuable species of fish regularly caught on the Great Barrier Reef.

To test the computer model's predictions 1,190 juvenile and 880 adult fish were tracked -- from spawning locations to settlement -- across the reef for two years.

The computer model recreates the movements of baby fish across space and time by considering what depth the coral trout swim at, how fast they swim, and how they orient themselves as they grow older.

The results highlighted the interconnectedness of reefs, and how important no-take zones are when considering future adult fish populations.

"Our results prove that the Great Barrier Reef's no-take zones are connected with invisible threads," Dr Bode said.

"Knowing how reefs are connected to one another means fishers and managers alike can identify which areas are likely to be most productive and need protecting," Dr Harrison said. "It's the babies from these protected areas that will continue to restock fish populations on neighbouring reefs where fishing is allowed."

Dr Bode said establishing the accuracy of these models is an important breakthrough.

"Our match between models and data provides reassuring support for using them as decision-support tools, but also directions for future improvement."

Michael Bode, Jeffrey M. Leis, Luciano B. Mason, David H. Williamson, Hugo B. Harrison, Severine Choukroun, Geoffrey P. Jones. Successful validation of a larval dispersal model using genetic parentage data. PLOS Biology, 2019; 17 (7): e3000380 DOI: 10.1371/journal.pbio.3000380
Fig 1. Study region and data.
(A) Location of the study region in the southern Great Barrier Reef, Australia. Stars highlight sampled reefs in each region. (B) 16-mm P. maculatus settlement-stage larva. Photo credit: C. Wen. (C) Observed connectivity network between the sampled reefs. Line and reef colours indicate the identity of the source region. Note that bidirectional connections were observed between all three regions. (D) Parentage connectivity matrix for the sampled reefs. Only a few rows and columns contain connections, because only a subset of reefs were sampled. (E) Connectivity matrix generated by the consistent biophysical model simulations, for all reefs in the three regions. Each row and column correspond to a reef in one of the three sampled regions. In both matrices, colours indicate the relative strength of dispersal, with purple > green > red. Biophysical simulations give a more complete picture of regional dispersal patterns, but the genetic parentage data are empirically defensible. The data used in this figure are given in S1 Data. Is, Islands

Turtle Embryos Play A Role In Determining Their Own Sex

August 1, 2019: Cell Press
In certain turtle species, the temperature of the egg determines whether the offspring is female or male. But now, new research shows that the embryos have some say in their own sexual destiny: they can move around inside the egg to find different temperatures. The study, publishing August 1 in the journal Current Biology, examines how this behaviour may help turtles offset the effects of climate change.

"We previously demonstrated that reptile embryos could move around within their egg for thermoregulation, so we were curious about whether this could affect their sex determination," says corresponding author Wei-Guo Du, professor at the Chinese Academy of Sciences. "We wanted to know if and how this behavior could help buffer the impact of global warming on offspring sex ratios in these species."

Du and his colleagues incubated turtle eggs under a range of temperatures both in the laboratory and in outdoor ponds. They found that a single embryo could experience a temperature gradient of up of 4.7°C within its egg. This is significant because any shift larger than 2°C can massively change the offspring sex ratio of many turtle species, Du said.

In half of the eggs, they applied capsazepine, a chemical that blocked temperature sensors, to prevent behavioural thermoregulation. After the eggs hatched, the researchers found that the embryos without behavioural thermoregulation had developed as either almost all males or almost all females, depending on the incubation temperatures. In contrast, embryos that were able to react to nest temperatures moved around inside their eggs; about half of them developed as males and the other half as females.

"The most exciting thing is that a tiny embryo can influence its own sex by moving within the egg," Du says.

By moving around the egg to find what Richard Shine, a professor at Macquarie University of Australia and one of the co-authors, calls the "Goldilocks Zone" -- where the temperature is not too hot and not too cold -- the turtles can shield against extreme thermal conditions imposed by changing temperatures and produce a relatively balanced sex ratio. "This could explain how reptile species with temperature-dependent sex determination have managed to survive previous periods in Earth history when temperatures were far hotter than at present," he says.

But this behaviour has limitations, Du says, depending on the conditions of the egg and the embryo itself. "Embryonic thermoregulation can be limited if the thermal gradient within an egg is too small, or if the embryo is too large to move around or too young to have developed these abilities yet," he says.

Additionally, the behaviour cannot buffer the impact of episodes of extremely high temperatures, which are predicted to increase with climate change, Du says.

"The embryo's control over its own sex may not be enough to protect it from the much more rapid climate change currently being caused by human activities, which is predicted to cause severe female-biased populations," he says. "However, the discovery of this surprising level of control in such a tiny organism suggests that in at least some cases, evolution has conferred an ability to deal with such challenges."

Du says that this study indicates that these species may have some ways not yet discovered to buffer this risk. "Our future studies will explore the adaptive significance of embryonic thermoregulation as well as the other behavioral and physiological strategies adopted by embryos and mothers to buffer the impact of climate warming on turtles."

Yin-Zi Ye, Liang Ma, Bao-Jun Sun, Teng Li, Yang Wang, Richard Shine, Wei-Guo Du. The Embryos of Turtles Can Influence Their Own Sexual Destinies. Current Biology, 2019; DOI: 10.1016/j.cub.2019.06.038

Barrenjoey Seal Colony Growing

Jools Farrell, local ORRCA member, reminds us that at present the Australian Fur Seal Colony at Barrenjoey is growing. In mid July there were 9 but there will be a lot more as we had up to 20 last year.



Please remember that legally you must stay a minimum of 40 metres away from seals, especially if they come ashore on the estuary beaches or ocean beaches to rest.

Also please keep an eye out for them if you are out in a boat as they do venture out of this spot to feed on the estuary or around Barrenjoey Headland. In recent years they have been seen everywhere from Barrenjoey to Clareville and Church Point.

Please do not attempt to feed them as they get plenty of food here in Pittwater. Please also do not attempt to swim with them, Jools asks.

If you do see a seal in distress, please contact ORRCA on their 24/7 hotline: 9415 3333.

Catch A Glimpse Of A Humpback Whale

Visit a coastal NSW national park to spot a humpback whale, as they start their annual migration north.

From May to November 2019, over 30,000 humpback whales will migrate from the cold waters of Antarctica to the warmer waters off north east Australia to mate and give birth before heading south again.

Vantage spots for whale watching include national parks with lookouts, headlands and foreshores.

Southern right and minke whales may also be spotted off the NSW coast during migration season.

Keen whale-watchers can download the free Wild About Whales mobile app, which helps users find the best locations for spotting whales, get real-time notifications of nearby sightings, and record their sightings.

Environment Minister Matt Kean said the app is a great tool for the whole family to learn more about whales, while also contributing to a citizen science project.

“Citizen science volunteers and other organisations such as ORRCA do an amazing job of monitoring the number of whales migrating along the NSW coast each season,” Mr Kean said.

Find whale watching vantage points

Learn about approaching marine mammals in NSW

Strong Evidence For Causal Link Between Obesity And Multiple Diseases

August 1, 2019: University of South Australia
A new study, led by Professor Elina Hyppönen from UniSA's Australian Centre for Precision Health, presents the strongest evidence yet of a causal relationship between obesity and a wide range of serious conditions, including cardiovascular disease, diabetes, cancer, and neurological, musculoskeletal and respiratory afflictions.

The study, published in Lancet Digital Health, draws data from the UK Biobank -- a research database holding health and genetic information from half a million volunteers -- to analyse associations between body mass index (BMI) and a range of disease outcomes in 337,536 people.

"In this study we used a genetic approach to seek evidence for true health effects associated with higher body mass index, which assesses our weight against our height and is commonly used to measure obesity," Prof Hyppönen says.

Previous research has suggested that high BMI is associated with increased risk of chronic diseases such as type 2 diabetes, cardiovascular disease and cancer, but due to the difficulty of conducting clinical trials related to obesity, it has been hard to prove causation.

Prof Hyppönen and her team developed a multi-dimensional analysis in which genetic data was subjected to a suite of stringent examinations in order to deliver high confidence of causality.

"We compared evidence from five different statistical approaches to establish how strong the evidence for causal effect actually is," she says.

"Fully consistent evidence across all approaches was seen for 14 different diseases, and for 26 different diseases evidence was obtained by at least for four of the five methods used.

"What increases the confidence that these associations are largely reflective of real effects is the fact that those effects which came across with consistent evidence are also ones for which we have previous clinical evidence."

One key finding from the study was the extent to which it confirms existing concerns over the link between obesity and diabetes, with many of the diseases identified as related to high BMI known to be commonly associated with poorly controlled diabetes.

"For example, we saw evidence for effects on peripheral nerve disorders, chronic leg and foot ulcers, and even gangrene and kidney failure, which are all known to be diabetic complications. This suggests a key aspect to reduce comorbidity risk in obesity is careful monitoring of blood sugar and effective control of diabetes and its complications," Prof Hyppönen says.

The study also highlights the importance of genetic research to further our understanding of the role genes play in obesity, and the insights it can provide for the future management and treatment of obesity.

"There is an urgent need to find new approaches to manage and prevent obesity," Prof Hyppönen says.

"We know that obesity has a strong genetic basis, which can make weight management very difficult to some of us and the same strategies for prevention may also not work for all. Genetic studies are giving us deeper insights into the biological pathways which drive obesity, and hopefully these types of studies will also provide us with new strategies for prevention."

Elina Hyppönen, Anwar Mulugeta, Ang Zhou, Vimaleswaran Karani Santhanakrishnan. A data-driven approach for studying the role of body mass in multiple diseases: a phenome-wide registry-based case-control study in the UK Biobank. The Lancet Digital Health, 2019; 1 (3): e116 DOI: 10.1016/S2589-7500(19)30028-7

Low Level Exposure To Air Pollution Is Harmful

August 1, 2019: University of Technology Sydney
Air pollution is made up of both gaseous and particulate matter (PM). Each year almost two million people die as a direct result of air pollution with many more experiencing impaired lung function, developing lung diseases such as asthma and chronic obstructive pulmonary disease (COPD). However research, on the effects of low level air pollution, is often overlooked.

An international research team, led by the University of Technology Sydney (UTS) and the Woolcock Institute of Medical Research (WIMR) investigated whether a low level of exposure to PM10 was harmful. PM10 refers to particles equal or below 10 microns in size, they make up a large proportion of air pollution and can enter the lung.

The results of the study have been published in the American Journal of Physiology -- Lung Cellular and Molecular Physiology (AJP-Lung).

Dr Yik Chan from UTS and WIMR, and co-lead author on the paper, said that low level air pollution was often mistakenly treated as "safe" and not harmful to health.

"In Sydney and other Australian capital cities the levels of traffic related air pollution (TRAP) are low by world standards and not often considered a problem in terms of developing chronic lung disease. However almost everyone living in an urban area is exposed to TRAP," Dr Chan said.

"Sydney has a lot of new construction taking place, as well as a growing population and increased traffic is inevitable," he said.

Researchers from the Kolling Institute, UNSW, Chinese University of Hong Kong, Chinese Academy of Sciences were also involved in the study that showed that, after three weeks, mice exposed to low levels of traffic related PM10 had an inflammatory response.

Chief Investigator Associate Professor Brian Oliver said that "these results have important implications for new [building] developments."

"For example, should schools or day care centres be built next to busy roads?

"Our results indicate that PM is a pro-inflammatory molecule, which exerts effects even at low concentrations. In our model we found strong, and statistically significant evidence of, lung inflammation and dysregulated mitochondrial activity. The mitochondria are the powerhouse of the cell, which means that any changes to the mitochondria effects energy production by the cell, and therefore how the cell divides and responds to external stimuli."

The researchers say that people living alongside major traffic corridors need to be aware of the potential adverse effects on their respiratory health.

Yik Lung Chan, Baoming Wang, Hui Chen, Kin Fai Ho, Junji Cao, Guo Hai, Bin Jalaludin, Cristan Herbert, Paul S Thomas, Sonia Saad, Brian G. Oliver. Pulmonary inflammation induced by low dose particulate matter exposure in mice. American Journal of Physiology-Lung Cellular and Molecular Physiology, 2019; DOI: 10.1152/ajplung.00232.2019

Cancer Without End? Discovery Yields Fresh Insights

August 1, 2019: Arizona State University
If there is any consolation to be found in cancer, it may be that the devastating disease dies with the individual carrying it. Or so it had long been assumed. Recent research however has uncovered some forms of cancer that are transmissible, jumping from one host to another. Indeed, one such contagious cancer, known as canine transmissible venereal tumor (CTVT), has managed to persist in dogs for thousands of years.

In a new commentary appearing in the August 2nd issue of the journal Science, Carlo Maley and Darryl Shibata describe the dynamics of this sexually transmitted disease, which arose in a single ancient animal, living as much as 8.5 millennia ago.

Intriguingly, the exploration of long-term, multi-generational cancer evolution in CTVT may shed new light on how human cancers evolve during the typical course of the disease and may inspire new approaches to treating cancer, which remains the second leading cause of death worldwide.

"Cancers evolve, and our strategies for managing cancer need to take that into account," Maley says. In the future, we hope to maintain long-term control over these evolving tumors. CTVT is fascinating because it shows us how cancers might evolve over the long term."

Maley is a researcher in the Biodesign Center for Biocomputing, Security and Society, the Center for Immunotherapy, Vaccines and Virotherapy and the Center for Mechanisms of Evolution at Arizona State University, as well as ASU's School of Life Sciences. He is the director of the newly established Arizona Cancer and Evolution Center (ACE). Shibata is a professor in the Department of Pathology at USC and the co-director of the ACE Center.

Ominous signs emerge
Examples of contagious cancers in humans exist, but they remain exceedingly rare and have never spread beyond a second host. Other animals however are less fortunate and may fall prey to a range of transmissible cancers, which vary in the severity of their impact.

In 1996, a mysterious illness began sweeping through animal populations in the central highlands of Tasmania. The island's Tasmanian devils were dying from a gruesome facial tumor. At first, a virus was the suspected culprit in the rapidly spreading epidemic. But when the DNA fingerprints of afflicted devils were examined, researchers made a remarkable discovery. The tumor cells were genetically distinct from the devil's own healthy cells, yet they matched tumor cells taken from other Tasmanian devils with the facial tumor disease. It was as though the tumor cells had been cloned and transplanted into each stricken animal. The disease was positively identified as an aggressively lethal, transmissible cancer.

The current commentary concerns CTVT, which causes grotesque, oozing tumors that afflict the genital area in dogs. When researchers sequenced cells from these tumors, the results mirrored those observed in the Tasmanian devils. All of the cancer cells shared a suite of genetic variants that did not appear in the dogs' healthy cells. This led to a startling conclusion: CTVT is not simply a disease that occasionally develops in dogs. It arose only once, in a single dog and has been transmitted through the ages from one animal to the next ever since.

When two dogs with CTVT were examined, one in Brazil and another in Australia, each belonging to a different breed, their tumor cells shared nearly 2 million mutations that were not found in normal canine DNA. While the CTVT genome diverged considerably from the original dog genome, it remained remarkably stable over time.

Dog years
Unlike the pitiless cancer devastating the Tasmanian devils, CTVT is rarely lethal. Instead, it typically persists for a matter of months before being cleared by the dog's immune system. (See drawing based on genetic sequencing of what the first dog carrying CTVT may have looked like.)

Recent investigations of CTVT, carried out by Adrien Baez-Ortega and colleagues, advance the unusual story of this disease. Their findings appear in the current issue of Science and are the focus of Maley and Shibata's commentary.

Baez-Ortega, a researcher at the University of Cambridge, sequenced tumors from 546 dogs around the world. The results showed the great antiquity of CTVT, which has been transmitted by dogs for 4000 to 8500 years. For evolutionary biologists like Maley and Shibata, the findings are revelatory, in part because CTCV appears to have stopped evolving long before it spread around the world.

New directions
The study of cells derived from transmissible cancers like CTVT provides valuable clues for biologists interested in the development of human cancers. Examining somatic cell evolution around the world and over significant spans of time helps researchers understand the subtle dynamics of the evolutionary processes involved in cancer. (In contrast, observing the life and death of cells over time in an individual patient is very difficult.)

Perhaps the most critical observation resulting from the genome sequencing of CTVT is that cancer is not an inevitably progressive disease. Rather, tumors may reach an optimal state that can stabilize over time, exhibiting little or no additional gains in biological fitness -- the ability to survive and reproduce.

Typically, tumors persevere and wreak havoc by generating numerous mutations. While most of these have no effect on cancer cell survival, or are even harmful, a few convey an adaptive advantage to cells, increasing their survivability. These are known as driver mutations and as the name implies, they are responsible for a successful cancer's relentless expansion. Driver mutations generate the cells that are able to resist cancer treatment.

It appears that CTVT has been evolving neutrally after its inception, accumulating mutations that do not affect fitness. The successful development of CTVT in dogs therefore seems to require only a few minor adjustments to the genome. The lack of ongoing natural selection in CTVT also suggests that the disease has not had a significant impact on dog survival and reproduction.

The stability of CTVT over time offers hope that certain slow-growing human cancers resistant to conventional therapy, for example prostate cancer, could be tamed and controlled. This might be achieved through so-called adaptive therapies, which seek to limit tumor growth as opposed to aggressive treatments aimed at total eradication, which invariably select for resistant and often lethal cell variants. A pilot clinical trial to test this approach in metastatic breast cancer will soon start at the Mayo Clinic's Arizona campus, in collaboration with ASU.

It seems likely that ongoing explorations of cell evolution in CTVT will provide further insights into complex cell trajectories and genetic transformations in a range of human cancers and inspire innovative methods of addressing the disease.

"Most cancers can only evolve for a few decades before they die with their host," Maley says. "CTVT is an incredible natural experiment, which showed us that it doesn't take much for a cancer to reach an optimal state. It is amazing that it did not discover additional adaptations over thousands of years, even as it infected all different breeds of dogs in all different environments around the world."

Carlo C. Maley, et al. Cancer cell evolution through the ages. Science, Aug 2nd, 2019 DOI: 10.1126/science.aay2859

Experimental Observation Of A New Class Of Materials: Excitonic Insulators

July 31, 2019: ARC Centre of Excellence in Future Low-Energy Electronics Technologies
A University of Wollongong / Monash University collaboration has found evidence of a new phase of matter predicted in the 1960s: the excitonic insulator.

The unique signatures of an excitonic insulating phase were observed in antimony Sb(110) nanoflakes.

The findings provide a novel strategy to search for more excitonic insulators which is potentially capable of carrying exicton superfluids, and further studies will be required to fully understand the rich physics of this new phase of matter.

Background
"The discovery of new phases of matter is one of the major goals of condensed matter physics and is important for developing new technologies for low energy electronics which is the main goal of the ARC center in FLEET," says Prof Xiaolin Wang (UOW).

"In the 1960s, it was proposed that in small indirect band-gap materials, excitons can spontaneously form because the density of carriers is too low to screen the attractive Coulomb interaction between electrons and holes." said by Dr Zhi Li, the first author and currently FLEET AI and an ARC DECRA fellow co-mentored by Prof Wang and Prof Fuhrer.

The result is a novel strongly interacting insulating phase known as an excitonic insulator.

In the insulator family, the first member is the bandgap, 'or 'trivial' insulator.

Besides bandgap insulators, other insulating states may arise through the effects of electron-electron interactions or disorder coupled with quantum interference, for example:

Anderson insulators, in which electrons are localized by quantum interference
Topological insulators, which have a gap in the bulk but gapless conducting states at the surface/edge due to band inversion.
The excitonic insulator, a new phase of matter in the critical transition point between insulator and metal was proposed in 1960s by many pioneers in condensed matter physics.

In an excitonic insulator, bosonic particles rather than electrons determine the physical properties.

Excitonic insulators have been predicted to host many novel properties, including crystallized excitonium, superfluidity and excitonic high-temperature superconductivity, and breakthroughs in finding this new class of insulators have attracted keen attention amongst condensed matter physicists and two-dimensional material scientists.

The study
The research team employed scanning tunnelling microscopy (STM) and spectroscopy (STS) to show that the enhanced Coulomb interaction in quantum-confined elemental antimony nanoflakes drives the system to the excitonic insulator state.

The unique feature of the excitonic insulator, a charge density wave (CDW) without periodic lattice distortion, was directly observed. Furthermore, STS shows a gap induced by the CDW near the Fermi surface.

These observations suggest that the antimony (Sb(110)) nanoflake is an excitonic insulator.

As well as funding by the Australian Research Council (Centre of Excellence, Future Fellowship, Discovery Projects, DECRA and LIEF funds and Laureate Fellowship), support was provided by the University of Wollongong Vice Chancellor's Postdoctoral Research Fellowship Scheme.

The theory
Excitons, which are bosonic, strongly-bound pairs of electrons and holes, are formed through the attractive electron?hole Coulomb interaction, lowering the system energy by the value of the binding energy (Eb).

If such excitons could form spontaneously, then the result would be an excitonic insulator phase.

In semiconductors or insulators, the formation of an exciton requires overcoming the band-gap energy Eg needed to create an electron?hole pair. The spontaneous formation of excitons demands that Eb > Eg. However, Eg is usually much larger than Eb in semiconductors and insulators, preventing spontaneous exciton formation.

In this work, the researchers took advantage of the strong Coulomb interaction in very thin materials to promote the excitonic insulator phase in antimony.

Previous work
Up to now, many materials showing CDW have been identified as the candidate of excitonic insulators.

Unfortunately, these candidate excitonic insulators show strong periodical lattice distortion (PLD), indicating CDW was driven by electron-phonon coupling rather than by excitonic insulator states.

The new study provides solid evidence of the excitonic insulator phase in antimony nanoflakes by the observation of CDW without PLD.

Zhi Li, Muhammad Nadeem, Zengji Yue, David Cortie, Michael Fuhrer, Xiaolin Wang. Possible Excitonic Insulating Phase in Quantum-Confined Sb Nanoflakes. Nano Letters, 2019; DOI: 10.1021/acs.nanolett.9b01123

Shining (Star)Light On The Search For Life

August 2, 2019: NASA/Goddard Space Flight Center
In the hunt for life on other worlds, astronomers scour over planets that are light-years away. They need ways to identify life from afar -- but what counts as good evidence?

Our own planet provides some inspiration. Microbes fill the air with methane; photosynthesising plants expel oxygen. Perhaps these gases might be found wherever life has taken hold.

But on worlds very different from our own, putative signs of life can be stirred up by non-biological processes. To know a true sign when you see it, astronomer Kevin France at the University of Colorado, Boulder, says, you must look beyond the planet itself, all the way to the gleaming star it orbits.

To this end, France and his team designed the SISTINE mission. Flying on a sounding rocket for a 15-minute flight, it will observe far-off stars to help interpret signs of life on the planets that orbit them. The mission will launch from the White Sands Missile Range in New Mexico in the early morning hours of Aug. 5, 2019.

When Earth Is a Bad Example
Shortly after Earth formed 4.6 billion years ago, it was enveloped by a noxious atmosphere. Volcanoes spewed methane and sulfur. The air teemed with up to 200 times more carbon dioxide than today's levels.

It wasn't for another billion and a half years that molecular oxygen, which contains two oxygen atoms, entered the scene. It was a waste product, discarded by ancient bacteria through photosynthesis. But it kick-started what became known as the Great Oxidization Event, permanently changing Earth's atmosphere and paving the way for more complex lifeforms.

"We would not have large amounts of oxygen in our atmosphere if we didn't have that surface life," France said.

Oxygen is known as a biomarker: a chemical compound associated with life. Its presence in Earth's atmosphere hints at the lifeforms lurking below. But as sophisticated computer models have now shown, biomarkers on Earth aren't always so trustworthy for exoplanets, or planets orbiting stars elsewhere in the universe.

France points to M-dwarf stars to make this case. Smaller and colder than our Sun, M-dwarfs account for nearly three-quarters of the Milky Way's stellar population. To understand exoplanets that orbit them, scientists simulated Earth-sized planets circling M-dwarfs. Differences from Earth quickly emerged.

M-dwarfs generate intense ultraviolet light. When that light struck the simulated Earth-like planet, it ripped the carbon from carbon dioxide, leaving behind free molecular oxygen. UV light also broke up molecules of water vapour, releasing single oxygen atoms. The atmospheres created oxygen -- but without life.

"We call these false-positive biomarkers," France said. "You can produce oxygen on an Earth-like planet through photochemistry alone."

Earth's low oxygen levels without life were a kind of fluke -- thanks, in part, to our interaction with our Sun. Exoplanet systems with different stars might be different. "If we think we understand a planet's atmosphere but don't understand the star it orbits, we're probably going to get things wrong," France said.

To Know a Planet, Study its Star
France and his team designed SISTINE to better understand host stars and their effects on exoplanet atmospheres. Short for Suborbital Imaging Spectrograph for Transition region Irradiance from Nearby Exoplanet host stars, SISTINE measures the high-energy radiation from these stars. With knowledge about host stars' spectra, scientists can better distinguish true biomarkers from false-positives on their orbiting planets.

To make these measurements, SISTINE uses a spectrograph, an instrument that separates light into its component parts.

"Spectra are like fingerprints," said Jane Rigby, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who uses the methodology. "It's how we find out what things are made of, both on our planet and as we look out into the universe."

SISTINE measures spectra in wavelengths from 100 to 160 nanometers, a range of far-UV light that, among other things, can create oxygen, possibly generating a false-positive. Light output in this range varies with the mass of the star -- meaning stars of different masses will almost surely differ from our Sun.

SISTINE can also measure flares, or bright stellar explosions, which release intense doses of far-UV light all at once. Frequent flares could turn a habitable environment into a lethal one.

The SISTINE mission will fly on a Black Brant IX sounding rocket. Sounding rockets make short, targeted flights into space before falling back to Earth; SISTINE's flight gives it about five minutes observing time. Though brief, SISTINE can see stars in wavelengths inaccessible to observatories like the Hubble Space Telescope.

Two launches are scheduled. The first, from White Sands in August, will calibrate the instrument. SISTINE will fly 174 miles above Earth's surface to observe NGC 6826, a cloud of gas surrounding a white dwarf star located about 2,000 light-years away in the constellation Cygnus. NGC 6826 is bright in UV light and shows sharp spectral lines -- a clear target for checking their equipment.

After calibration, the second launch will follow in 2020 from the Arnhem Space Centre in Nhulunbuy, Australia. There they will observe the UV spectra of Alpha Centauri A and B, the two largest stars in the three-star Alpha Centauri system. At 4.37 light-years away, these stars are our closest stellar neighbors and prime targets for exoplanet observations. (The system is home to Proxima Centauri B, the closest exoplanet to Earth.)

Testing New Tech
Both SISTINE's observations and the technology used to acquire them are designed with future missions in mind.

One is NASA's James Webb Space Telescope, currently set to launch in 2021. The deep space observatory will see visible to mid-infrared light -- useful for detecting exoplanets orbiting M-dwarfs. SISTINE observations can help scientists understand the light from these stars in wavelengths that Webb can't see.

SISTINE also carries novel UV detector plates and new optical coatings on its mirrors, designed to help them better reflect rather than absorb extreme UV light. Flying this technology on SISTINE helps test them for NASA's future large UV/optical space telescopes.

By capturing stellar spectra and advancing technology for future missions, SISTINE links what we know with what we've yet to learn. That's when the real work starts. "Our job as astronomers is to piece those different data sets together to tell a complete story," Rigby said.
The Alpha Centauri system in optical (main) and X-ray (inset) light. Only the two largest stars, Alpha Cen A and B, are visible. These two stars will be the targets of SISTINE's second flight. Credits: Zdenek Bardon/NASA/CXC/Univ. of Colorado/T. Ayres et al.