Cancer: Fatty acid in palm oil promotes tumour metastasis in mice

Nature

Vast areas of rain forest habitat continue to be cleared for oil palm plantations like
this in Sarawak. Photo credit: Ben Sutherland

Exposure to high concentrations of a dietary fatty acid contained in palm oil promotes the metastasis of mouth and skin cancer cells in mice, according to a paper published in Nature.

Changes in the uptake and metabolism of fatty acids have been linked to cancer metastasis — the process by which cancer cells spread to other parts of the body. However, it is unclear which dietary fatty acids in particular might be responsible for these changes, and the biological mechanisms involved.

Salvador Benitah and colleagues exposed human mouth and skin cancer cells to one of three types of dietary fatty acid — palmitic acid (the main saturated fatty acid in palm oil), oleic acid or linoleic acid — for four days, before introducing them into corresponding tissues in mice fed a standard diet. Although tumour initiation was not found to be influenced by any of the fatty acids studied, palmitic acid significantly increased both the penetrance and size of existing metastatic lesions. No such significant effect was observed for oleic or linoleic acid.

Pro-metastatic cancer cells also retained ‘memory’ of exposure to high levels of palmitic acid. For example, tumours from mice fed a palm-oil-rich diet for only ten days or tumour cells exposed to palmitic acid in the laboratory transiently for four days (before returning to normal medium) remained highly metastatic even when transplanted into mice fed on a normal diet. This process is associated with epigenetic changes — molecular modifications that alter patterns of gene expression without the DNA itself being altered — in metastatic cells that are suggested to mediate the long-term stimulation of metastasis.

The findings may aid in the identification of new therapies, the authors conclude.

Farmers on the Canadian prairies set fire to their fields - are they placing their reputation as "stewards of the land" on the line?

by Larry Powell

SHOAL LAKE, MANITOBA, CANADA: As dedicated, well-meaning people gathered in Scotland to find ways to counter our climate crisis, farmers on the Canadian prairies were waging a "scorched earth" war on their fields.  By taking advantage of severe drought that has rendered those fields tinder-dry, they were able to effectively burn down marsh-plants - mostly cattails in and around wetlands diminished by that same drought. 

Farmers commonly use specially-fitted quads like this to light fires on their land. 
PinP photos. 

Dozens of such fires could be spotted each day for many days this fall in the vicinity of my own community in southwestern Manitoba, too.

So, do they really "get" the adage, "Think globally. Act locally?" 

You be the judge.

Airguns and ship sounds dangerously disrupt the natural behaviour of the "unicorn of the sea." Study

The Royal Society - Biology Letters

A pod of narwhals in the Arctic.

Manmade noise is increasing in the Arctic, posing a threat to narwhals. To study this, narwhals were fitted with tags and exposed to ship and airgun noise. The whales showed clear reactions to sound disturbance by first reducing and then ceasing foraging. Reactions could be detected as far as 40 km from the ship, where the signals were embedded in the natural background noise. The reactions of the whales demonstrate their sensitivity and emphasize that - "if healthy narwhal populations are to be maintained," humans need to "manage" activities that make such noise.

The findings have just been published by the Royal Society.

Please also read:

RAPIDLY WARMING OCEANS HAVE LEFT MANY NORTHERN MARINE MAMMALS SWIMMING IN TROUBLED WATERS. BUT PERHAPS NONE MORE SO THAN THAT STRANGE AND MYSTERIOUS "UNICORN OF THE SEA," THE NARWHAL.

Baleens - beneficial gluttons of the high seas

Scientists believe the ravenous appetites of baleen whales - Earth's largest creatures - and their prodigious waste - hold clues to the very health and productivity of our oceans.

by Larry Powell

A blue whale (Balaenoptera musculus) defecates. Photo credit-Ryan Lavery (Smithsonian)

Baleens include humpbacks, fins, minkes and blue whales, the latter being the largest creatures ever to live on Earth. The carnivorous marine mammals catch and consume vast amounts of prey. And they recycle ocean nutrients by excreting undigested food in what have been described as "volcano-like" movements.

A minke whale tagged by the research team off the coast of Antarctica in 2019. Credit: Ari Friedlaender under NOAA/NMFS permit 23095.

By attaching tags to the backs of 321 whales from seven baleen species, the researchers now reckon that - before the onset of whaling in the twentieth century - and in the Southern Ocean alone - baleens were, amazingly, consuming more than twice what the world's entire marine fisheries catch today. 

A humpback whale feeds on sand lance in the Stellwagen Bank National Marine Sanctuary. Credit: Elliott Hazen

Yearly, they probably ate 430 million tonnes of Antarctic krill (small crustaceans found in all the world's oceans) before whaling ramped up in the 19 hundreds in the Atlantic, Pacific, and Southern Oceans. That's up to thirty percent of their entire body mass, on average, and, in some areas of the ocean at least, triple the volume previously thought. And, incredibly, it's twice the total biomass of this entire species of krill thought to exist today. 

The scientists hope, if baleen numbers could somehow recover to what they were before that twentieth century whaling, their "nutrient recycling services" could not only help boost ocean productivity but restore ecosystem functions to their previous glory.

According to the Smithsonian Institute, heavily involved in the study, whales both eat and excrete immense amounts of iron. It is an important nutrient which spurs the growth of phytoplankton blooms. If it weren't for the whales, this valuable commodity would sink from near the surface, where the whales live (and where the iron is needed), to the bottom where it would be lost. 

These findings have just been published in the journal, Nature.

Declining Arctic sea ice may increase wildfires in the western US - & Canada?

Nature

Declining sea ice in the Arctic may contribute to increased wildfire activity in the western United States, suggests a modelling study published in Nature Communications. The finding demonstrates the influence that human-induced climate change can have on extreme weather events in the region.

Wildfires in the western US (& Canada) have become more frequent and severe in recent years. Although there is some evidence that Arctic sea ice declines can influence extreme weather conditions in temperate and subtropical regions, the impact on wildfires has been unclear.

Yufei Zou, Hailong Wang and colleagues combined data on wildfire incidence, sea ice concentrations and weather conditions over the past 40 years and conducted model simulations to investigate the relationship between these factors. 

The authors identified an association between declining Arctic sea ice concentrations from July to October and the increasing probability of large wildfires in the western US during the following September to December. The model simulations indicate that declines in Arctic sea ice are linked to air circulation changes that cause hotter and dryer weather conditions, which increase the likelihood of wildfires.

The authors conclude that the influence of Arctic sea ice concentrations on wildfires is of similar magnitude to that of the tropical El Niño Southern Oscillation, which can also modulate regional wildfire conditions. As Arctic sea ice is projected to continuously decline, this could further increase the susceptibility of the western US to wildfires in the future, they suggest.

Major toilet paper brands are flushing our forests down the drain

The National Observer

What runs through your mind when you’re deciding which toilet paper to buy? Sale price, roll size, pitiful single-ply or luxurious triple? Climate change might not make your list of considerations, but it should. Story here.

Please also watch this video.

"Truth in Advertising - a TV commercial as it should be"

Australian bushfires triggered prolific phytoplankton blooms vast distances away

Nature

Bushfire East of Lake Dundas, Western Australia. Photo by Pierre Markuse

The 2019–2020 Australian wildfires released more than twice as much CO2 as previously reported on the basis of different fire inventories, reports a Nature paper. 

An independent study also published in Nature, suggests that aerosol emissions from these wildfires are likely to have fuelled vast plankton blooms thousands of kilometres away in the Southern Ocean. 

The findings highlight the complex links between wildfires, ecosystems and the climate. Climate-change-driven droughts and warming play a role in increasing the frequency and intensity of wildfires, which release CO2 into the atmosphere, potentially driving further climate change and increasing the risk of wildfires. 

In the summer season of 2019–2020, around 74,000 km2 — an area roughly equivalent to 2.5 times the area of Belgium — burned in the eucalyptus forests in the coastal regions of Victoria and New South Wales, Australia. These wildfires are known to have been extremely large in scale and intensity, and to have released large amounts of CO2 into the atmosphere, but emission estimates remain uncertain.

To gain insights into the amount of CO2 released by the Australia wildfires, Ivar Van der Velde and colleagues analysed new high-resolution satellite measurements of carbon monoxide concentration in the atmosphere, from which they infer fire-induced carbon emissions. They estimated that around 715 teragrams of CO2 were emitted between November 2019 and January 2020 — more than twice the amount previously estimated from five different fire inventories and comparable to a bottom-up bootstrap analysis of this fire episode, surpassing Australia’s normal annual fire and fossil fuel emissions by 80%. 

Gaining a stronger understanding of the atmospheric burden of CO2 caused by these fires, and what they will cause in the future, is critical for constructing future scenarios of the global carbon balance, the authors note.

In addition to carbon emissions, wildfires release aerosols that affect ecosystems; for example, transportation of nutrients such as nitrogen and iron can enhance plankton growth. Nicolas Cassar, Weiyi Tang and colleagues report the presence of extensive phytoplankton blooms from December 2019 to March 2020 in the Southern Ocean, downwind of the fires. Aerosol samples originating from the fires contained high levels of iron, which the authors suggest were transported vast distances and fertilized the blooms.

Together, these studies demonstrate that wildfires can have an important influence on atmospheric CO2 levels and ocean ecosystems.