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Post by lowell on May 25, 2022 2:01:16 GMT -6
"Fruit fly experiments shed new light on dangers of plastic ingestion"
By Nick Lavars May 24, 2022
"A new study in fruit flies has hinted at the dangers of ingesting microplastics" Depositphotos
' The evidence is starting to build around the ability of tiny fragments of plastic to make their way into all corners of the human body, with these particles recently discovered in living lungs and the bloodstream for the first time. What this means for our health is still a big unknown, but scientists have turned to trusty fruit flies as a model in search of answers to this question, tracking the particles through the intestinal tract to find they alter gene expression involved in stress response and oxidative damage.
Though research has started to paint a picture of what small plastic particles might mean for marine organisms, findings which include aneurysms in fish, impaired cognitive function in hermit crabs and swimming abnormalities in shrimp, our understanding of the human impacts is more limited.
Lab studies has shown they can alter the shape of lung cells and have toxic effects on human cells more broadly, but understanding how they behave inside the living body is another question entirely. To explore this, scientists at the Universitat Autònoma de Barcelona used one of the most well-understood of model organisms in the fruit fly Drosophila melanogaster, a long-favored tool for scientific research due to the large percentage of disease-sharing genes they share with humans.
The scientists say the fruit fly approach also overcomes some of the limitations in measuring plastic accumulation in human tissues. Working with polystyrene fragments of different sizes, the scientists used transmission electron microscopy to follow the path of the particles from their ingestion until they reached the haemolymph of fruit fly larvae, the equivalent to blood in humans.
This enabled them to produce a kind of "photographic report" revealing the behavior of the plastics as they interacted with microbiota and cells while moving through the intestinal tract. This revealed an ability to cross the intestinal barrier and enter the haemolymph. Though the scientists report no evidence of significant toxicity, the plastic particles did trigger broad molecular changes that altered the expression of genes involved in general stress response.
The particles also altered the gene expression associated with oxidative damage and damage to the DNA, along with genes relating to a response to physical damage of the intestinal barrier. The particles used in the study were 50, 200 and 500 nanometers in size, and interestingly, the scientists found that the smaller they were, the higher responses they induced.
"Our work adds information on what happens, in terms of effects, when the exposure is to nanoplastics, which, due to their small size, are of particular relevance to us, because of their greater capacity to break down biological barriers and produce toxicological effects that can affect the health of organisms, including humans," says Alba Hernández Bonilla, co-author of the study.
"Images track the journey of plastic particles after ingestion by fruit flies, eventually winding up in the haemolymph, the equivalent to blood in humans"
Universitat Autònoma de Barcelona
Studies continue to illuminate the wide variety of sources for human exposure to microplastics, with disposable coffee cups and plastic water bottles that shed huge amounts of particles into the liquids they contain among the key culprits. Meanwhile, scientists also consider airborne particles between 1 nanometer and 20 micrometers to be respirable, meaning that the particles at the center of this study may have a direct route into the body via inhalation.
"In addition to establishing a new methodological approach, our study confirms the great advantages of Drosophila melanogaster as a model to determine the potential harmful effects associated with the ingestion of these pollutants," explains Ricard Marcos, coordinator of the study.
The research was published in the journal Environmental Science: Nano. '
Source: Universitat Autònoma de Barcelona
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Post by lowell on Jun 11, 2022 17:03:15 GMT -6
"First microplastics discovered in freshly fallen Antarctic snow"
By Nick Lavars June 09, 2022
"Researchers log details of a snow sampling site in Antarctica" Bella Zeldis
' The ongoing discovery of microplastics in remote, seemingly pristine corners of the world continues to add important detail to a troubling picture of widespread pollution, and the latest finding takes the threat into new terrain. In freshly fallen snow in the Antarctic scientists have uncovered the first evidence of microplastics, which presented in even higher concentrations than previously reported in the surrounding seas.
As scientists expand the scope of their studies into the spread of plastic waste, tiny fragments of the material continue to turn up in all kinds of places, some more surprising than others. The breakdown of things like shopping bags and soda bottles is a well-known source of microplastic pollution in the ocean, but these have recently been found to get swept up with the wind, reach the upper parts of Mt Everest, build up in Arctic sea ice and snow, and accumulate in the agricultural soils of Europe.
When University of Canterbury PhD student Alex Aves set out on a research expedition to Antarctica's Ross Ice Shelf in 2019, her colleagues didn't see the discovery of microplastics in the area as a strong possibility.
“When Alex traveled to Antarctica in 2019, we were optimistic that she wouldn’t find any microplastics in such a pristine and remote location,” said Associate Professor in Environmental Physics Dr Laura Revell. "We asked her to collect snow off the Scott Base and McMurdo Station roadways, so she’d have at least some microplastics to study.”
Upon her return to the lab with snow samples in tow, the team analyzed them with a technique called micro-Fourier transform infrared spectroscopy, and found some depressing surprises. These inspections indeed revealed microplastics in the snow samples from the Ross Ice Shelf, and in every one of the samples collected at all sites throughout the expedition.
“It’s incredibly sad but finding microplastics in fresh Antarctic snow highlights the extent of plastic pollution into even the most remote regions of the world,” said Aves. “We collected snow samples from 19 sites across the Ross Island region of Antarctica and found microplastics in all of these.”
The researchers found an average of 29 microplastic particles per liter of snow, which they note is a higher concentration than previously reported in the surrounding Ross Sea and Antarctic sea ice. In samples collected around the research bases, the concentration was three times higher. Thirteen different types of plastic were found in the samples, with the PET used in soda bottles and clothing the most common.
“Looking back now, I’m not at all surprised,” said Revell. “From the studies published in the last few years we’ve learned that everywhere we look for airborne microplastics, we find them.”
While we have much to learn about the dangers of microplastic contamination, early studies have highlighted some concerning possibilities. These include impairing growth, reproduction and cognitive ability in marine organisms, inducing toxic effects on human cells, and potential links to high cholesterol and heart disease. The spread of microplastics into Antarctic snowfall indicates it's nigh-on impossible to avoid such dangers, no matter where you are.
"Whilst research around the impacts of nano- and microplastics is still in its infancy, they are being seen to affect organisms and ecosystems in a variety of ways," said Dr Olga Pantos, Senior Scientist at New Zealand's Institute of Environmental Science and Research. "It is therefore of concern that yet another remote ecosystem is exposed to more impacts resulting from human activity."
The research was published in the journal The Cryosphere. '
Sources: University of Canterbury, Scimex
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Post by lowell on Jun 11, 2022 17:38:56 GMT -6
"Mouse study shows microplastics infiltrate blood brain barrier"
By Nick Lavars November 23, 2021
"A new study has shown how microplastics can infiltrate the blood brain barrier of mice" plp609/Depositphotos
' Much of the millions of metric tons of plastic waste that washes into the sea each year is broken down into tiny fragments by the forces of the ocean, and researchers are beginning to piece together what this means for organisms that consume them. Scientists in Korea have turned their attention toward the top of the food chain by exploring the threat these particles pose to mammal brains, where they were found to act as toxic substances.
In recent years, studies have revealed the kind of threat microplastics pose to marine creatures. This has included weakening the adhesive abilities of muscles, impairing the cognitive ability of hermit crabs and causing aneurysms and reproductive changes in fish. They've turned up in the guts of sea turtles all over the world, and been discovered in seal poo as evidence of them traveling up the food chain. Research has also shown they can alter the shape of human lung cells.
To further our understanding of these dangers, researchers at Daegu Gyeongbuk Institute of Science and Technology orally administered polystyrene microplastics two micrometers in size or smaller to mice over the course of seven days. Like humans, mice have a blood-brain barrier that prevents most foreign substances, and especially solids, from entering the organ, but the scientists found that the microplastics were able to make their way through.
Once in the brain, the scientists found that the particles built up in the microglial cells, which are key to healthy maintenance of the central nervous system, and this had a significant impact on their ability to proliferate. This was because the microglial cells saw the plastic particles as threat, causing changes in their morphology and ultimately leading to apoptosis, or programmed cell death.
Additionally, the scientists carried out experiments on human microglial cells and also observed changes in their morphology, along with changes to the immune system via alterations to the expression of relevant genes, related antibodies and microRNAs. As seen in the mouse brains, this also induced signs of apoptosis.
“The study shows that microplastics, especially microplastics with the size of 2 micrometers or less, start to be deposited in the brain even after short-term ingestion within seven days, resulting in apoptosis, and alterations in immune responses, and inflammatory responses," says study author Dr. Seong-Kyoon Choi." Based on the findings of this research, we plan to conduct additional research that can further reveal the brain accumulation of microplastics and the mechanism of neurotoxicity."
The research was published in the journal Science of The Total Environment. '
Source: Daegu Gyeongbuk Institute of Science and Technology
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