Vaccine-associated enhanced disease: Case definition and guidelines for data collection, analysis, and presentation of immunization safety data Flor M. Munoz, Jakob P. Cramer, and for the Brighton Collaboration Vaccine-associated Enhanced Disease Working Group https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901381/

Vaccine-associated enhanced diseases (VAED) are modified presentations of clinical infections affecting individuals exposed to a wild-type pathogen after having received a prior vaccination for the same pathogen [1]. Vaccine-associated enhanced respiratory (VAERD) disease refers to disease with predominant involvement of the lower respiratory tract.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901381/

Classic examples of VAED are atypical measles and enhanced respiratory syncytial virus (RSV) occurring after administration of inactivated vaccine for these pathogens. In this situation, severe disease has been documented resulting from infection in individuals primed with non-protective immune responses against the respective wild-type viruses [2], [3], [4], [5], [6]. Given that these enhanced responses are triggered by failed attempts to control the infecting virus, VAED typically presents with symptoms related to the target organ of the infection pathogen. In order to recognize vaccine associated disease enhancement, it is therefore necessary to have a clear understanding of the clinical presentation and usual course of the natural disease.

Disease enhancement independent of vaccine priming has also been described for pathogens causing sequential infections with different cross-reactive but not cross-protective serotypes, including dengue and pandemic influenza [7], [8], [9], [10], [11], [12].

In late 2019, a novel severe respiratory illness emerged in Wuhan, China [13]. The causative agent, Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), was promptly identified, and determined to be closely related to SARS and the Middle East Respiratory Syndrome (MERS) coronaviruses, which had caused geographically localized outbreaks in 2002–2004 and from 2012 onwards, respectively. SARS-CoV-2 progressed to a global pandemic with substantial consequences due to its high infectivity and transmissibility, and its ability to cause both a severe respiratory illness, and a systemic disease with fatal consequences for vulnerable populations. The natural history of coronavirus infectious disease caused by SARS-CoV-2 (COVID-19), is yet to be fully described. However, a case fatality rate that ranges from 0.5% to nearly 20% depending on age and other risk factors, and the understanding that SARS-CoV-2 is now a well-adapted human pathogen that will continue to cause disease in susceptible populations, makes the development of an effective vaccine a global priority.

The potential for vaccination against SARS-CoV-2 to be associated with disease enhancement is of theoretical concern, given similar observations with other respiratory viruses in general, and in animal models of highly pathogenic coronaviruses in particular [14]. Importantly, VAED has not been seen following SARS or MERS vaccines given to humans, albeit the number of people who received these experimental vaccines remains very small. At this time, the pathogenesis, host responses and immunity to SARS-CoV-2 are still being evaluated and are not fully understood. SARS-CoV-2 infection is associated with a spectrum of disease that varies from asymptomatic infection to severe lung disease with acute respiratory distress syndrome (ARDS) and a fatal multiorgan disease with inflammatory, cardiovascular, hematologic and coagulation dysregulation [15], [16], [17]. Post-infectious, possibly immune-mediated systemic disease has also been described, particularly the multisystemic inflammatory syndrome in children (MIS-C) and adults (MIS-A) of unclear pathogenesis at this time [18], [19], [20], [21].

Given the broad spectrum of disease associated with SARS-CoV-2, clinical assessment of both systemic VAED and lung-specific VAERD will be challenging during the pre-licensure evaluation of candidate vaccines and after the implementation of widespread vaccination for COVID-19. The broad spectrum of natural disease manifestations in different populations and age groups makes it very difficult, if not impossible, to determine how severe COVID-19 infection would have been in the absence of vaccination in the individual case. Someone who might have been completely asymptomatic without prior vaccination but who develops mild respiratory symptoms in association with prior vaccination could logically be considered a case of VAERD. However, this end of the spectrum of possible VAERD would have very little clinical significance for this individual person. At the population level however, even a small shift in the spectrum of disease towards greater severity could have major clinical and societal impact. Furthermore, given that severe illness is more feasible to detect and characterize, the case definitions discussed herein focus on the more severe presentations of VAED/VAERD.

There is no uniformly accepted definition of VAED or VAERD. Frequently used related terms include “vaccine-mediated enhanced disease (VMED)”, “enhanced respiratory disease (ERD)”, “vaccine-induced enhancement of infection”, “disease enhancement”, “immune enhancement”, and “antibody-dependent enhancement (ADE)”. This is potentially confusing as the mechanisms for disease enhancement likely vary, and data comparability across trials or surveillance systems can be problematic when the systems do not utilize a consistent case definition and do not collect comparable data. However, the assessment of this potential adverse event following immunization is particularly important for SARS-CoV-2, given the urgent global need for safe and effective vaccines. While this case definition was developed for the identification of potential cases of VAED/VAERD in the context of SARS-CoV-2 vaccine development, it is not exclusive for COVID-19 vaccines and may be applied in the evaluation of possible VAED/VAERD after any vaccine.

Vaccine-associated enhanced disease: Case definition and guidelines for data collection, analysis, and presentation of immunization safety data Flor M. Munoz, Jakob P. Cramer, and for the Brighton Collaboration Vaccine-associated Enhanced Disease Working Group https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901381/

Vaccine-associated enhanced disease: Case definition and guidelines for data collection, analysis, and presentation of immunization safety data
Flor M. Munoz, Jakob P. Cramer, and for the Brighton Collaboration Vaccine-associated Enhanced

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901381/

Disease Working Group

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901381/

Vaccine-associated enhanced diseases (VAED) are modified presentations of clinical infections affecting individuals exposed to a wild-type pathogen after having received a prior vaccination for the same pathogen [1]. Vaccine-associated enhanced respiratory (VAERD) disease refers to disease with predominant involvement of the lower respiratory tract. Classic examples of VAED are atypical measles and enhanced respiratory syncytial virus (RSV) occurring after administration of inactivated vaccine for these pathogens. In this situation, severe disease has been documented resulting from infection in individuals primed with non-protective immune responses against the respective wild-type viruses [2], [3], [4], [5], [6]. Given that these enhanced responses are triggered by failed attempts to control the infecting virus, VAED typically presents with symptoms related to the target organ of the infection pathogen. In order to recognize vaccine associated disease enhancement, it is therefore necessary to have a clear understanding of the clinical presentation and usual course of the natural disease.

Disease enhancement independent of vaccine priming has also been described for pathogens causing sequential infections with different cross-reactive but not cross-protective serotypes, including dengue and pandemic influenza [7], [8], [9], [10], [11], [12].

In late 2019, a novel severe respiratory illness emerged in Wuhan, China [13]. The causative agent, Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), was promptly identified, and determined to be closely related to SARS and the Middle East Respiratory Syndrome (MERS) coronaviruses, which had caused geographically localized outbreaks in 2002–2004 and from 2012 onwards, respectively. SARS-CoV-2 progressed to a global pandemic with substantial consequences due to its high infectivity and transmissibility, and its ability to cause both a severe respiratory illness, and a systemic disease with fatal consequences for vulnerable populations. The natural history of coronavirus infectious disease caused by SARS-CoV-2 (COVID-19), is yet to be fully described. However, a case fatality rate that ranges from 0.5% to nearly 20% depending on age and other risk factors, and the understanding that SARS-CoV-2 is now a well-adapted human pathogen that will continue to cause disease in susceptible populations, makes the development of an effective vaccine a global priority.

The potential for vaccination against SARS-CoV-2 to be associated with disease enhancement is of theoretical concern, given similar observations with other respiratory viruses in general, and in animal models of highly pathogenic coronaviruses in particular [14]. Importantly, VAED has not been seen following SARS or MERS vaccines given to humans, albeit the number of people who received these experimental vaccines remains very small. At this time, the pathogenesis, host responses and immunity to SARS-CoV-2 are still being evaluated and are not fully understood. SARS-CoV-2 infection is associated with a spectrum of disease that varies from asymptomatic infection to severe lung disease with acute respiratory distress syndrome (ARDS) and a fatal multiorgan disease with inflammatory, cardiovascular, hematologic and coagulation dysregulation [15], [16], [17]. Post-infectious, possibly immune-mediated systemic disease has also been described, particularly the multisystemic inflammatory syndrome in children (MIS-C) and adults (MIS-A) of unclear pathogenesis at this time [18], [19], [20], [21].

Given the broad spectrum of disease associated with SARS-CoV-2, clinical assessment of both systemic VAED and lung-specific VAERD will be challenging during the pre-licensure evaluation of candidate vaccines and after the implementation of widespread vaccination for COVID-19. The broad spectrum of natural disease manifestations in different populations and age groups makes it very difficult, if not impossible, to determine how severe COVID-19 infection would have been in the absence of vaccination in the individual case. Someone who might have been completely asymptomatic without prior vaccination but who develops mild respiratory symptoms in association with prior vaccination could logically be considered a case of VAERD. However, this end of the spectrum of possible VAERD would have very little clinical significance for this individual person. At the population level however, even a small shift in the spectrum of disease towards greater severity could have major clinical and societal impact. Furthermore, given that severe illness is more feasible to detect and characterize, the case definitions discussed herein focus on the more severe presentations of VAED/VAERD.

There is no uniformly accepted definition of VAED or VAERD. Frequently used related terms include “vaccine-mediated enhanced disease (VMED)”, “enhanced respiratory disease (ERD)”, “vaccine-induced enhancement of infection”, “disease enhancement”, “immune enhancement”, and “antibody-dependent enhancement (ADE)”. This is potentially confusing as the mechanisms for disease enhancement likely vary, and data comparability across trials or surveillance systems can be problematic when the systems do not utilize a consistent case definition and do not collect comparable data. However, the assessment of this potential adverse event following immunization is particularly important for SARS-CoV-2, given the urgent global need for safe and effective vaccines. While this case definition was developed for the identification of potential cases of VAED/VAERD in the context of SARS-CoV-2 vaccine development, it is not exclusive for COVID-19 vaccines and may be applied in the evaluation of possible VAED/VAERD after any vaccine.

Practice the Precautionary Principle.Unacceptable Risk: Dr. Margaret Kripke on Cancer and the Environment, tells the story of a prominent cancer researcher who began to rethink her assumptions about the causes of cancer and the true burden of environmentally-induced cancers.

For National Cancer Prevention Month, Silent Spring Institute and our partners at the Cancer Free Economy Network are excited to share with you the release of a new documentary film, Unacceptable Risk: Dr. Margaret Kripke on Cancer and the Environment.

Unacceptable Risk learn more at http://www.CancerFreeEconomy.org/UnacceptableRisk.

Dr. Kripke is a professor emerita at MD Anderson Cancer Center. She is on the Board of Directors at Silent Spring and also serves as chair of Silent Spring’s Leadership Council.

We are thrilled to see her story elevated in this way as it speaks directly to the imperative need for prevention research.

Watch the 15-minute documentary and be sure to share the film with your friends and family!

‘Unacceptable Risk: Dr. Margaret Kripke on Cancer and the Environment’ tells the story of a prominent cancer researcher who started to rethink her assumptions about the causes of cancer and the true burden of environmentally induced cancers.

Watch it at http://www.CancerFreeEconomy.org/UnacceptableRisk.

Cyanobacterial neurotoxin BMAA and brain pathology in stranded dolphins

Cyanobacterial neurotoxin BMAA and brain pathology in stranded dolphins
David A. Davis, Kiyo Mondo, Erica Stern,Ama K. Annor, Susan J. Murch, Thomas M. Coyne, Deborah C. Mash Published: March 20, 2019

https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0213346#sec017

Dolphin stranding events occur frequently in Florida and Massachusetts. Dolphins are an excellent sentinel species for toxin exposures in the marine environment. In this report we examine whether cyanobacterial neurotoxin, β-methylamino-L-alanine (BMAA), is present in stranded dolphins. BMAA has been shown to bioaccumulate in the marine food web, including in the muscles and fins of sharks. Dietary exposure to BMAA is associated with the occurrence of neurofibrillary tangles and β-amyloid plaques in nonhuman primates. The findings of protein-bound BMAA in brain tissues from patients with Alzheimer’s disease has advanced the hypothesis that BMAA may be linked to dementia.

Plummeting insect numbers ‘threaten collapse of nature’ https://www.theguardian.com/environment/2019/feb/10/plummeting-insect-numbers-threaten-collapse-of-nature?CMP=Share_iOSApp_Other

Plummeting insect numbers ‘threaten collapse of nature’

https://www.theguardian.com/environment/2019/feb/10/plummeting-insect-numbers-threaten-collapse-of-nature?CMP=Share_iOSApp_Other

Cancer killing plant

A little-known plant with a truly bizarre name is now making headlines as a cancer killer, with the compound of the plant vanishing tumors in mice with pancreatic cancer. Known as the “Tripterygium Wilfordii” or Lei Gong Teng sometimes called “Thunder God Vine”, the Chinese plant is actually integrated into Chinese medicine and has been used for ages in remedying a number of conditions including rheumatoid arthritis.
According to the new research out of the University of Minnesota’s Masonic Cancer Center, the thunder god plant compound led to no signs of tumors after a 40 day period — even after discontinuing the treatment. Published in the journal Science Translational Medicine and funded by the National Institutes of Health, even the scientists working on the project were stunned by the anti-cancer properties of the compound. Known to contain something known as triptolide, which has been identified as a cancer fighter in previous research, it is thought to be the key component that may be responsible for the anti-tumor capabilities.
Study leader and vice chairman of research at the Cancer Center explained to Bloomberg how he was blown away by the effects of the simple plant:
“This drug is just unbelievably potent in killing tumor cells,” he said.
And just like with numerous other powerful substances like turmeric and ginger, mainstream science is still slowly confirming what many traditional practitioners have known for their entire lives. This is, of course, due to the fact that there is simply no money for major corporations in researching the healing powers of natural herbs and compounds such as the compound found in the thunder god vine. Turmeric and ginger, for example, have been found to be amazing anti-cancer substances that are virtually free compared to expensive and dangerous cancer drugs.
Nevertheless, the Big Pharma sponsored corporate scientists have managed to ignore these spices as much as possible. In fact, they have even been caught time and time again faking thousands of studies to fraudulently demonstrate the supposed value of pharmaceutical drugs pushed by major pharma juggernauts — many of which are later forced to pay millions in fines which only slightly stack up against their billions in profits.
Profits that are threatened by the many real studies that were performed by scientists examining the rejeuvenating power of cheap ingredients like turmeric, which has been found by peer-reviewed research available on PubMed to positively influence over 590 conditions.
While it is great news that this study is bringing the beneficial effects of inexpensive and near-free plant compounds to light, the bad news is that the individuals responsible for the research are actually looking to create a pharmaceutical drug from the essential component triptolide. A drug that will seek FDA approval and ultimately be patented, nutritionally ruined, and sold for exorbitant amounts of cash. Instead, just get your hands on some thunder god vine for yourself.

Weed killing Herbicide found in cereals

Weed-killing chemical found in pasta, cereal and cookies sold in Canada: study | CTV News

https://www.ctvnews.ca/mobile/health/weed-killing-chemical-found-in-pasta-cereal-and-cookies-sold-in-canada-study-1.4086615

Weed-killing chemical found in pasta, cereal and cookies sold in Canada: study

From Cheerios to Oreos to chocolate glazed Timbits, a controversial weed-killing chemical has been found in several popular food products in Canada.

In a study commissioned by advocacy group Environmental Defence Canada and independently conducted by California-based Anresco Laboratories, 18 common food items were tested for glyphosate, the active ingredient of a chemical herbicide sold under the name Roundup and found in many agricultural and gardening products.

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Although the issue remains hotly contested, several studies and court cases have linked the widely-used chemical to cancer.

In the Environmental Defence Canada study, traces of glyphosate were found in multiple children’s foods and snacks sold in Canada, including Kraft Dinner Original macaroni and cheese, Ritz Original crackers, President’s Choice tortillas, two brands of hummus, breakfast cereals like General Mills’ Cheerios and Kellogg’s Froot Loops as well as Tim Hortons chocolate glazed Timbits and sesame seed bagels.   (Scroll down for a full list of the tested products and their glyphosate content)

Of the 18 products tested, only four did not contain glyphosate. And while the levels detected were in parts per billion — a minute amount that’s far below the levels deemed safe by Health Canada, which are set in parts per million — the fact there are trace amounts of a weed killer in foods in the first place may surprise many Canadians

Muhannad Malas, Toxics Program Manager at Environmental Defence, said the findings suggest that some consumers may be unknowingly ingesting trace amounts of the disputed herbicide multiple times a day.

“When we have evidence that a chemical is linked to cancer, I think questions need to be raised about, you know, what is a safe a limit?” Malas told CTV News. “What we’re trying to do here is really inform Canadians and let Canadians know that these are the facts, that our foods contain glyphosate and that glyphosate is a harmful chemical.”

A controversial chemical

In August, a California jury ruled that the herbicide was directly responsible for causing a man’s terminal cancer. But numerous reports, including one from Health Canada last year, found that the product poses no health risks.

Glyphosate is registered for use in more than 160 countries, making it the most widely-used weed killer in the world. Because it is sprayed on a variety of crops — from corn to soybeans to wheat — the chemical can end up in the harvested material that is used in food processing.

Companies with products named in the Environmental Defence Canada report told CTV News that they followed Health Canada guidelines and that their products are safe.

Bayer, which bought Roundup maker Monsanto in June, also insists that the chemical poses absolutely no harm.

“Glyphosate has more than a 40-year history of safe use. Over those four decades, researchers have conducted more than 800 scientific studies and reviews that prove glyphosate is safe for use,“ Bayer Canada’s Crop Science Division said in a written statement. (The full text of that statement has been included at the end of this article.)

The scientific community is also torn over whether or not ingesting glyphosate is harmful.

Health Canada’s most recent study of glyphosate, in 2017, found that the herbicide in low levels was “unlikely to pose a human cancer risk” and allowed it to be used for another 15 years.

That conclusion still stands, according to the Canadian Food Inspection Agency.

“To date, none of the levels of glyphosate found in products through the CFIA surveys have been deemed to be a health risk by Health Canada and no recalls were warranted,” said spokesperson Karelle Beaudoin in a statement.

Similar findings have been released by the European Food Safety Authority, the European Chemicals Agency, the U.S. Environmental Protection Agency and the Australian Pesticides and Veterinary Medicines Authority.

Len Ritter, a professor of environmental toxicology at the University of Guelph, described the level of herbicides in the new report “extraordinarily low.”

“They’re not the kinds of levels with which we would be concerned toxicologically. So what would people get from this? I think nothing at all, quite frankly,” Ritter said.

Studying possible harm

Some reports, however, have raised serious concerns about the chemical. In 2015, the World Health Organization’s International Cancer Research Agency (IARC)declared that glyphosate is a “probable carcinogen.” California has also added glyphosate to its list of chemicals known to cause cancer. (Aspirin, coffee and aloe vera have also made the list.)

Other animal-based studies suggest that the chemical can lead to reproductive issues among mammals and is harmful to bees, fish and rats.

Stephanie Seneff, a senior research scientist with the MIT Computer Science and Artificial Intelligence Laboratory, has studied the long-term effects of glyphosate on human health. She described the use of the herbicide as “a gigantic experiment that been going on for 40 years.”

“I see very strong correlations between the rise in a long list of debilitating autoimmune, neurological and oncological diseases exactly in step with the rise in use of glyphosate on core crops,” Seneff said.

In August, moreover, a San Francisco jury ordered Monsanto to pay US$289 million to a former school groundskeeper, saying that Roundup contributed to his terminal cancer.

Shares of Bayer, which acquired Monsanto in June, plunged 11 per cent immediately following the verdict. Bayer confirmed it was facing more than 8,700 similar lawsuits as of Aug. 27.

Dewayne Johnson, the former groundskeeper who had been accidentally doused with the chemical, said the ruling was “way bigger than me.”

“I hope it gets the attention that it needs,” Johnson said following the decision.

Previous studies have found traces of the chemical in human urine, breast milk, beer and several common foods.

Cereals Canada responds

Farmers around the world commonly use glyphosate to kill weeds and control pests. But the U.S.-based Environmental Working Group says American farmers are increasingly spraying the chemical on oats and some other crops to help dry out the plants and harvest them sooner.

Grain producers say the herbicide is widely used and effective. Cam Dahl, president of Cereals Canada, said it’s important to consider the small amount of herbicide found in the 18 products.

“If people want to know what a part per billion is, you would have to eat about 36,000 full loaves of bread in a single day to get to the allowable daily limit of glyphosate. So these are very, very small, small numbers,” Dahl said.

Industry group Food & Consumer Products of Canada (FCPC) also weighed in on the report, calling the glyphosate levels “significantly below” the government’s safety requirements.

“FCPC recognises that glyphosate presence in foods may be of concern to Canadians. We are in regular consultation with regulatory authorities, academics, and our members to ensure the continued safety of our food,” said spokesperson Michelle Kurtz in a statement.

Glyphosate-free foods

Despite disagreements over the safety of glyphosate in foods, several companies are now joining a growing trend by actively marketing glyphosate-free products. Many of those companies have sought certification from The Detox Project, a California-based group that describes itself as a “research and certification platform that encourages transparency in the food and supplement industries on the subject of toxic chemicals.”

“The revelation from WHO’s International Agency for Research on Cancer (IARC) in 2015 that glyphosate is a ‘probable carcinogen’ has led to consumers across the globe asking for transparency regarding the levels of glyphosate in their food,” the group adds on its website. “The global success of the Non-GMO food market has shown that consumers are pushing for more and more transparency and pesticides is even higher on their list of concerns than GMOs.”

COMPANIES RESPOND

Companies with products tested by Environmental Defence Canada, as well as Bayer Canada, responded to questions from CTV News about the presence of glyphosate.

Sabra Dipping Company, Sabra Classic Hummus

“Producing wholesome, safe, delicious food is Sabra’s number one priority and we stand behind our products 100%.  We have a comprehensive quality program that encourages agricultural best practices, to ensure that only the best possible ingredients are used in our products.  In particular, we carefully comply with applicable laws relating to food safety, including laws that regulate any possible pesticide residues.”

Kraft Heinz Canada, Kraft Dinner Original Noodles

“Our products are safe and comply with Health Canada’s regulations. Health Canada has also evaluated various products including commodities like wheat found in pastas and found no human health concerns. In fact, as can be seen from the report, our product contains a small percentage of the amount Health Canada considers safe for wheat.”

Mondelez Canada, Ritz Original Crackers and Oreo Original Cookies

“Mondelēz Canada is committed to producing the highest quality foods possible. To this end we are also mindful about potential residues that may be in raw materials. To be assured that raw materials purchased by Mondelēz Canada are safe and suitable for us and our consumers, we take the additional step to monitor our raw materials to ensure that they meet appropriate specifications, our own standards AND that of the government  (FDA, EPA for US & Health Canada, CFIA for Canada).  Additionally, we hold our suppliers to those same standards. Importantly, our products which are mentioned in this report are in full compliance with Health Canada’s regulations.”

Fontaine Santé, Roasted Garlic Hummus

“We proudly stand by the safety and quality of our Fontaine Santé products. Preparing healthy products is Fontaine Santé’s number one priority, and we’ve been doing that for 28+ years.

Fontaine Santé makes all natural products using wholesome ingredients and does not add any glyphosate during the preparation of its products. Glyphosate, is a herbicide that is approved by regulatory agencies and is commonly used by farmers across the industry who apply it pre-harvest.

Fontaine Santé continually evaluates its product portfolio to ensure the highest quality and safety standards for our consumers. While the Fontaine Santé products comply with all safety and regulatory requirements, we are happy to be part of the discussion and are interested in collaborating with industry peers, regulators and other interested parties on glyphosate.”

PepsiCo, Quaker Large Flake Oats

“We proudly stand by the safety and quality of our Quaker products. Producing healthy, wholesome food is Quaker’s number one priority, and we’ve been doing that for more than 140 years.  Quaker does not add glyphosate during any part of the milling process. Glyphosate is commonly used by farmers across the industry who apply it pre-harvest. Once the oats are transported to us, we put them through our rigorous process that thoroughly cleanses them (de-hulled, cleaned, roasted and flaked).  Any levels of glyphosate that may remain are significantly below any regulatory limits and well within compliance of the safety standards set by Health Canada, the Environmental Protection Agency (EPA) and the European Food Safety Authority (EFSA) as safe for human consumption. Quaker continually evaluates our product portfolio to ensure the highest quality and safety standards for our consumers. While our products comply with all safety and regulatory requirements, we are happy to be part of the discussion and are interested in collaborating with industry peers, regulators and other interested parties on glyphosate.”

Tim Hortons, chocolate glazed Timbits and sesame seed bagels

“At Tim Hortons, we stand by the integrity of our products. Nothing is more important to us than the quality of the food we serve our guests. In this case, Health Canada’s position is clear: dietary risks from food and water are “not of concern.” We remain committed to working with our suppliers to ensure our products meet the highest standards for food safety and quality.”

Bayer Canada, Crop Science Division

“Environmental Defence Canada is a social action environmental group that has as one of its mandates opposing the use of chemicals in everyday products, including products like glyphosate. Glyphosate is a widely-used and effective herbicide with a 40-year history of safe use. Canada’s health authorities have extensively reviewed glyphosate and approved it for use according to label instructions.

It is not uncommon to find trace amounts of pesticides in food since some food is grown using pesticides, which protects crops from insects, disease and weeds.  Importantly, these levels reported by Environmental Defense Canada are not even remotely close to any level of concern.  These numbers must be put into meaningful context:

For chickpea based foods, the highest reported value was 760 parts per billion in hummus. At this level, an adult would have to eat 28 kg of hummus every day for life to reach PMRA’s allowable exposure limit.  That’s over a kilogram of hummus every hour of every day for life without sleeping.

For wheat-based foods (744 parts per billion in tortillas), an adult would have to eat 28 kg of tortillas every day for the life to reach PMRA’s allowable exposure limit.  That’s 430 tortillas per day. Every day.

Regulatory authorities have strict rules when it comes to pesticide residues.  Health Canada’s Pest Management Regulatory Agency (PMRA) and the U.S. Environmental Protection Agency (EPA), for example, set daily exposure limits at least 100 times below levels show to have no negative effect in safety studies. Health Canada has clearly stated there is no risk from eating conventionally-grown foods because of pesticide residues.

Glyphosate has more than a 40-year history of safe use. Over those four decades, researchers have conducted more than 800 scientific studies and reviews that prove glyphosate is safe for use.“

With a report from CTV’s medical affairs specialist Avis Favaro and producer Elizabeth St. Philip

Biodegradation of synthetic polymers in soils: Tracking carbon into CO2 and microbial biomass

http://advances.sciencemag.org/content/4/7/eaas9024
Biodegradation of synthetic polymers in soils: Tracking carbon into CO2 and microbial biomass

1. Michael Thomas Zumstein¹,*,Arno Schintlmeister²,³,Taylor Frederick Nelson¹,Rebekka Baumgartner¹, Dagmar Woebken²,Michael Wagner²,³,Hans-Peter E. Kohler⁴,Kristopher McNeill¹ and Michael Sander¹,†

Abstract

Plastic materials are widely used in agricultural applications to achieve food security for the growing world population. The use of biodegradable instead of nonbiodegradable polymers in single-use agricultural applications, including plastic mulching, promises to reduce plastic accumulation in the environment. We present a novel approach that allows tracking of carbon from biodegradable polymers into CO₂ and microbial biomass. The approach is based on ¹³C-labeled polymers and on isotope-specific analytical methods, including nanoscale secondary ion mass spectrometry (NanoSIMS). Our results unequivocally demonstrate the biodegradability of poly(butylene adipate-co-terephthalate) (PBAT), an important polyester used in agriculture, in soil. Carbon from each monomer unit of PBAT was used by soil microorganisms, including filamentous fungi, to gain energy and to form biomass. This work advances both our conceptual understanding of polymer biodegradation and the methodological capabilities to assess this process in natural and engineered environments.

INTRODUCTION

Modern agriculture heavily relies on the use of plastic materials in various applications, a practice coined plasticulture. Mulching with plastic films is a major application with a global market volume of approximately 2 × 10⁶ tons per year (1). Mulch films are placed onto agricultural soils to improve conditions for plant growth while lowering consumption of water, herbicides, and fertilizer and also minimizing soil erosion (1, 2). Because of these benefits, mulching with plastic films helps to secure food for the growing world population. However, mulch films are commonly composed of nonbiodegradable polyethylene and, therefore, accumulate in agricultural soils and surrounding receiving environments if incompletely retrieved after use. These accumulations have negative ecologic and economic impacts, including decreased soil productivity (3–5). A promising strategy to overcome these risks is to use mulch films composed of polymers that biodegrade in soils (1, 6–8).

Biodegradation of polymers requires microorganisms to metabolize all organic components of the polymer. Biodegradation in soil involves several key steps (Fig. 1): (i) colonization of the polymer surface by microorganisms, (ii) secretion of extracellular microbial enzymes that depolymerize the polymer into low–molecular weight compounds, and (iii) microbial uptake and utilization of these compounds, incorporating polymer carbon into biomass or releasing it as CO₂ (9).

Fig. 1 Key steps in the biodegradation of polymers in soils.

Microorganisms colonize the polymer surface and secrete extracellular enzymes that depolymerize the polymer. The formed low–molecular weight hydrolysis products are taken up by the microorganisms and used both for energy production, resulting in the formation of CO₂, and for the synthesis of cellular structures and macromolecules, resulting in incorporation of polymer-derived carbon into the microbial biomass. The boxes on the right depict the analytical methods we used to study these steps. NMR, nuclear magnetic resonance.

Fig. 1 Key steps in the biodegradation of polymers in soils.Microorganisms colonize the polymer surface and secrete extracellular enzymes that depolymerize the polymer. The formed low–molecular weight hydrolysis products are taken up by the microorganisms and used both for energy production, resulting in the formation of CO₂, and for the synthesis of cellular structures and macromolecules, resulting in incorporation of polymer-derived carbon into the microbial biomass. The boxes on the right depict the analytical methods we used to study these steps. NMR, nuclear magnetic resonance.Here, we examined each of the above steps for poly(butylene adipate-co-terephthalate) (PBAT), an aliphatic-aromatic statistical copolyester of large importance in the market of biodegradable mulch films (7). While previous studies provided indirect indications for PBAT biodegradation in soils based on determining PBAT mass loss and changes in its physicochemical properties (10–12), we here use a novel workflow using stable carbon isotope-labeled PBAT to directly and unequivocally demonstrate its biodegradation in soil (table S1). This workflow included incubation of ¹³C-labeled polymer films in soil with continuous quantification of polymer-derived ¹³CO₂ by isotope-specific cavity ring-down spectroscopy (CRDS) (13). The use of ¹³C-labeled polymers allowed us to distinguish polymer-derived CO₂ from CO₂formed by soil organic matter mineralization. After incubation, we imaged the polymer film surfaces using scanning electron microscopy (SEM) and demonstrated the incorporation of polymer-derived ¹³C into the biomass of film-colonizing microorganisms using element-specific, isotope-selective nanoscale secondary ion mass spectrometry (NanoSIMS) (14). We studied three PBAT variants that had similar physicochemical properties and comparable total ¹³C contents, but varied in the monomer that contained the ¹³C-label [that is, butanediol (P*BAT), adipate (PB*AT), or terephthalate (PBA*T)] (Fig. 2A and table S2). The use of these variants allowed us to follow biodegradation of all PBAT building blocks. The presented workflow is a novel approach to study the fundamental steps in polymer biodegradation in complex systems (15–17).

DISCUSSION

This work presents an experimental approach to study polymer biodegradation in soils and to assess the key steps involved in this process: microbial polymer colonization, enzymatic depolymerization on the polymer surface, and microbial uptake and utilization of the released low–molecular weight compounds. Central to the approach is the use of polymer variants that are ¹³C-labeled in all monomer units of the polymer, thereby allowing us to assess whether all organic components of the polymer material are used by soil microorganisms. The label further allows tracing of polymer-derived carbon into both CO₂ and microbial biomass. Using this approach, we demonstrate here the biodegradability of PBAT in soil. Biodegradability renders PBAT a more environmentally friendly alternative to persistent polymer materials for use in plasticulture, including single-use applications such as plastic mulching. Our results further imply that incorporation of polymer-derived carbon into microbial biomass needs to be taken into consideration in regulatory guidelines for determining biodegradability of polymers. Currently, these guidelines are solely based on extents of CO₂ formation. Furthermore, the finding of subcellular structures within PBAT-colonizing fungi highly enriched in polymer-derived carbon might represent compartments in which carbon is stored (for example, in the form of neutral lipids) when fungi are limited by the availability of nutrients other than carbon (22). These limitations are plausible for microorganisms growing on PBAT and other polymers that do not contain nitrogen and phosphorous. If these limitations occur, increasing the availability of soil nutrients to microorganisms colonizing the polymer surface is expected to enhance polymer biodegradation.

This work demonstrates PBAT biodegradation in a selected agricultural soil over 6 weeks of incubation. Future studies extending on this work will need to assess variations in the rates and extents of PBAT mineralization among different agricultural soils, also over longer-time incubations. Furthermore, we propose studies that are directed toward identifying soil microorganisms that are actively involved in PBAT biodegradation. While the NanoSIMS-based approach presented here allows us to unambiguously demonstrate incorporation of polyester carbon into soil microbial biomass, it is not a high-throughput technique. Alternative approaches, including the extraction of targeted biomolecules from soils containing ¹³C-labeled polymers followed by quantifying the ¹³C contents in the extracted molecules, will allow us to analyze larger sample sets and thereby to systematically determine potential variations among soil microorganisms in the extent to which they incorporate polymer-derived carbon into their biomass.

MATERIALS AND METHODS

Experimental design

The objective of this study was to develop an experimental approach to demonstrate biodegradation of PBAT in an agricultural soil. As biodegradation includes mineralization of PBAT carbon to CO₂, as well as the incorporation of PBAT-derived carbon into the biomass of soil microorganisms, we addressed both of these processes in controlled laboratory experiments. We followed PBAT mineralization during soil incubation using an isotope-specific CRDS for the quantification of formed CO₂. For each of the three PBAT variants, we simultaneously incubated seven films in one incubation bottle filled with soil to allow precise quantification of PBAT mineralization to CO₂. The soil incubations were terminated after 6 weeks (that is, when approximately 10% of the PBAT carbon had been mineralized) to ensure that PBAT films were still intact for the subsequent imaging analyses. We revealed incorporation of PBAT-derived carbon into biomass using NanoSIMS, which enabled identification of subcellular features and determination of the carbon isotope composition of the PBAT film surface and the colonizing microorganisms at submicrometer spatial resolution. The low throughput of this high-end topochemical analysis technique constrained the number of collected images for soil-incubated films to two images for each of the three PBAT variants including replicate films. We note that we did not exclude any data or outliers from our analysis.

Polyesters, monomers, soil, and enzymes

Polyesters were provided by BASF SE and synthesized as previously described (23, 24). The physicochemical properties of the polyesters are listed in table S2. To obtain similar ¹³C contents for the three PBAT variants (that is, PB*AT, P*BAT, and PBA*T), synthesis of all variants was performed with defined ratios of labeled to unlabeled monomers. The three PBAT variants were free of chemical additives.

The ¹³C-labeled monomers 1,6-¹³C₂-adipate and ¹³C₄-butanediol used for PBAT synthesis and for soil incubation studies were purchased from Sigma, with more than 99% of the indicated positions in the monomer containing ¹³C. We obtained 1-¹³C₁-terephthalate from dimethyl 1-¹³C-terephthalate purchased from Sigma. To obtain the free diacid, we dissolved dimethyl 1-¹³C-terephthalate in 2:1 water/tetrahydrofuran (5 mg in 2.4 ml), added 25 μl of a sodium hydroxide solution [37% (w/w)], and stirred the solution at room temperature for 2 hours. The solvent was then carefully removed under reduced pressure to obtain the hydrolysis product 1-¹³C₁-terephthalate (confirmed by ¹H NMR).

For PBAT and monomer incubations in soils under controlled laboratory conditions, we used agricultural soils from the agricultural center Limburgerhof (Rhineland-Palatinate, Germany). Physicochemical properties of the soils are provided in table S1. The soils were air-dried to a humidity of 12% of the maximum water-holding capacity of the soil, passed through a 2-mm sieve, and stored in the dark at 4°C for 12 months before use in the incubation experiments.

R. oryzae lipase was purchased as a powder from Sigma (catalog no. 80612). FsC was obtained as a solution from ChiralVision B.V. (Novozym 51032). Stock solutions of both enzymes in water were stored at −20°C.

Preparation of PBAT films and soils for incubation experiments

We prepared two sets of solvent-cast PBAT films that differed in the way that the PBAT films were attached to the silicon wafer substrates. For the first set, we solvent-cast PBAT films by adding three times 15 μl of a PBAT solution in chloroform [concentration, 5% (w/w)] onto a square-cut antimony-doped silicon wafer platelet (7.1 mm × 7.1 mm × 0.75 mm, Active Business Company). In between the additions of the polymer solutions, we allow the chloroform to evaporate. This procedure resulted in a PBAT mass of approximately 3 mg per wafer. Before incubation in soil, the solvent-cast polyester films were stored in the dark at room temperature for 1 week to ensure complete evaporation of the solvent (chloroform). PBAT variants from this first set were used for PBAT mineralization experiments (Fig. 2B), SEM imaging (Fig. 2C), and NanoSIMS imaging (Figs. 3 and 4 and fig. S8).

For the second set of PBAT films, we pretreated the silicon wafer platelets with Vectabond (Vector Laboratories, catalog no. SP-1800) before solvent casting of the polyester films. This second set of PBAT films was included to test whether the adhesion of the PBAT to the Si surface can be improved by this modified protocol. For the pretreatment, we exposed the wafers to a 1:50 diluted solution of Vectabond in acetone, subsequently dipped them into MilliQ water (Barnstead Nanopure Diamond), and dried them in a stream of N₂. PBAT variants from this set were used only to determine PBAT mineralization (fig. S1), but not for SEM and NanoSIMS imaging.

We prepared the soil for PBAT incubations by adding MilliQ water to the soil to adjust its water content to 47% of its maximum water-holding capacity. We subsequently transferred 60 g of the soil into each of the incubation vessels (100-ml glass Schott bottles). We prepared a total of nine incubation bottles in three sets of three bottles (see below). The soils were then preincubated at 25°C in the dark for 1 week.

After soil preincubation, we transferred the wafers carrying the solvent-cast polyester films into the soils in the incubation bottles. We added seven wafers to each incubation bottle. The wafers were spaced apart by at least 1 cm. All wafers were positioned upright in the soil. The three bottles of the first set each contained films of one of the three differently labeled PBAT variants obtained by direct solvent casting. The three bottles of the second set were identical to the first set except for the wafers, which were pretreated with Vectabond before solvent casting. The three bottles in the third set served as controls and contained soil but no PBAT films. All bottles were incubated for 6 weeks at 25°C in the dark. We note that our study therefore does not address potential effects of ultraviolet irradiation–induced changes in the structure of PBAT on its biodegradability. Over the course of the incubation, we gravimetrically determined the water content of the soils at defined time intervals. To sustain a constant soil water content, amounts of water that were lost from the soil through evaporation were replenished by adding corresponding amounts of MilliQ water.

Preparation and SEM imaging of soil-incubated PBAT films

After 6 weeks of incubation in soil, we carefully removed the silicon wafers carrying the PBAT films from the soils. To chemically fix the cells attached to the surfaces of the PBAT films, we directly transferred the films into a freshly prepared fixation solution (pH 7.4) containing glutaraldehyde (2.5%), sodium cacodylate (0.1 M), sodium chloride (0.1 M), potassium chloride (3 mM), and sodium phosphate (0.1 M). The films were exposed to this solution for 20 min at 25°C and subsequently transferred to a solution of OsO₄ in MilliQ water (1%) for 30 min of exposure on ice. Finally, we dehydrated the films in a series of water/ethanol solutions of increasing concentrations (70%, 5 min; 95%, 15 min; 100%, 2 × 20 min), followed by critical point drying of the samples with liquid CO₂ (Baltec CPD 030). Critical point drying resulted in detachment of the PBAT films from the wafer. To reattach the films to the wafers for further analyses, we used a double-sided adhesive, electrically conducting carbon tape (Ted Pella, product no. 16084-1). Directly after mounting the films onto the wafers with carbon tape, thin films of platinum (thickness, 10 nm) were deposited on the samples using a sputter coater (Baltec SCD 500). SEM was conducted on a Zeiss Supra 50 VP. Imaging was performed with a secondary electron detector at a working distance of 4.0 mm and an electron high tension of 5.0 kV. These films were also used for NanoSIMS analysis (see below).

PBAT films from the second set, for which wafers were pretreated with Vectabond before solvent casting of PBAT (see above), also detached from the wafers. We decided to reject further analysis of these films (that is, SEM and NanoSIMS).

PBAT film imaging by NanoSIMS

NanoSIMS measurements were performed on a NanoSIMS NS50L (Cameca) at the Large-Instrument Facility for Advanced Isotope Research (University of Vienna). Before data acquisition, analysis areas were presputtered by scanning of a high-intensity, slightly defocused Cs⁺ ion beam (beam current, 400 pA; spot size, approximately 2 μm). To avoid crater edge effects, scanning during presputtering was conducted over square-sized areas with an edge length exceeding the frame size of the subsequently recorded images by at least 15 μm. Every data set acquired on the soil-incubated polymer films contains image data recorded from (at least) two distinct depth levels, accessed by sequential presputtering with Cs⁺ ion fluences of 5.0 × 10¹⁶ and 2.0 × 10¹⁷ ions/cm², respectively. Application of the lower ion dose density enabled sampling of all cells within the analysis areas, irrespective of their size and/or morphology, whereas the extended presputtering allowed us to gain insight into cellular features contained within the lumen of bulky cells such as fungal hyphae (see, for example, Fig. 4).

Imaging was conducted by sequential scanning of a finely focused Cs⁺ primary ion beam (2-pA beam current) over areas ranging from 45 × 45 μm² to 70 × 70 μm² at a physical resolution of approximately 70 nm (that is, probe size) and an image resolution of 512 × 512 pixels. If not stated otherwise, images were acquired as multilayer stacks with a per-pixel dwell time of 1.5 ms per cycle. ¹²C⁻, ¹³C⁻, ¹²C¹²C⁻, ¹²C¹³C⁻, ¹²C¹⁴N⁻, ³¹P⁻, and ³²S⁻ secondary ions as well as secondary electrons were simultaneously detected, and the mass spectrometer was tuned for achieving a mass resolving power of >9.000 (according to Cameca’s definition) for detection of C₂⁻ and CN⁻ secondary ions. Image data were analyzed with the ImageJ plugin OpenMIMS, developed by the Center for NanoImaging (27). Secondary ion signal intensities were corrected for detector dead time (44 ns) and quasi-simultaneous arrival (QSA) of secondary ions. Both corrections were performed on a per-pixel basis. QSA sensitivity factors (“beta values”) were obtained from measurements on dried yeast cells, yielding 1.1, 1.06, and 1.05 for C⁻, C₂⁻, and CN⁻ secondary ions, respectively. Before stack accumulation, images were corrected for positional variations originating from primary ion beam and/or sample stage drift. ROIs were manually defined on the basis of ¹²C¹⁴N⁻ secondary ion signal intensity distribution images and cross-checked by the topographical/morphological appearance indicated in the simultaneously recorded secondary electron images (see fig. S10). While each cell from unicellular organisms was assigned to an individual ROI, image regions within the polyester surfaces and hyphae were segmented into multiple ROIs. Throughout the article, the carbon isotope composition is displayed as the ¹³C/(¹²C + ¹³C) isotope fraction, given in at%, calculated from the C⁻ and C₂⁻ secondary ion signal intensities via ¹³C⁻/(¹²C⁻ + ¹³C⁻) and ¹³C¹²C⁻/(2⋅¹²C¹²C⁻ + ¹³C¹²C⁻), respectively. Owing to superior counting statistics, all carbon isotope composition data shown in the article were inferred from C₂⁻signal intensities. We note that we did not observe any significant differences between ¹³C content values inferred from C₂⁻ signal intensities versus C⁻ signal intensities. For the line scan analyses displayed in Fig. 4, C₂⁻ normalized C¹⁴N⁻ signal intensities were used as an indicator of the relative nitrogen content {calculated via [¹²C¹⁴N⁻ (1 + ¹³C/¹²C)]/[¹²C¹³C⁻ + ¹²C₂⁻ (1 + (¹³C/¹²C)²)], whereby the term ¹³C/¹²C refers to the ¹³C-to-¹²C isotope ratio, calculated from the C₂⁻ signal intensities via ¹³C¹²C⁻/(2⋅¹²C¹²C⁻)}. This quantity formally refers to the relative nitrogen-to-carbon elemental ratio and was used in favor of the relative nitrogen concentration, which is inferable from C⁻ normalized C¹⁴N⁻ signal intensities, to minimize artifacts arising from the considerable topography within the areas of the fungal hyphae (28).

SUPPLEMENTARY MATERIALS

Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/7/eaas9024/DC1

Supplementary Materials and Methods

Fig. S1. Mineralization of PBAT films.

Fig. S2. NMR analysis of enzymatic hydrolysis products of PBAT films I.

Fig. S3. NMR spectra of terephthalate, adipate, and butanediol.

Fig. S4. NMR analysis of enzymatic hydrolysis products of PBAT films II.

Fig. S5. NMR analysis of enzymatic hydrolysis products of PBAT films III.

Fig. S6. NMR analysis of enzymatic hydrolysis products of PBAT films IV.

Fig. S7. Mineralization of terephthalate, adipate, and butanediol.

Fig. S8. NanoSIMS analysis of PBAT films after soil incubation I.

Fig. S9. Control experiment for NanoSIMS analysis I.

Fig. S10. Definition of ROIs.

Fig. S11. Control experiment for NanoSIMS analysis II.

Fig. S12. NanoSIMS analysis of PBAT films after soil incubation II.

Table S1. Soil characterization.

Table S2. Characterization of PBAT variants.

Supplementary Appendix. Calculations of the carryover during NanoSIMS measurements.

References (29–33)

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.

Acknowledgments: We thank S. Probst, M. Jaggi, and F. Strasser for their help with growing E. coli, performing IRMS measurements, and NanoSIMS control sample preparation and data analysis, respectively. Funding: M.T.Z., T.F.N., R.B., H.-P.E.K., K.M., and M.S. thank the Joint Research Network on Advanced Materials and Systems of BASF SE and ETH Zürich for scientific and financial support. M.W. and A.S. were supported by the European Research Council Advanced Grant project NITRICARE 294343. D.W. was supported by the European Research Council Starting Grant project DormantMicrobes 636928. SEM imaging was performed at the Center for Microscopy, University of Zurich. Author contributions: M.T.Z., A.S., D.W., H.-P.E.K., K.M., and M.S. designed the study. M.T.Z., A.S., T.F.N., and R.B. performed experiments. All authors contributed to the writing of the manuscript. Competing interests: The authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate our conclusions are present in the paper and/or the Supplementary Materials. Additional data related to this paper may be requested from the authors.

• Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).

 

 

 

Is bamboo the answer to citrus greening in Florida ?

   Is bamboo the answer to citrus greening in Florida

At the present time, USA production of bamboo products provides but a tiny fraction of the national and international demand which is growing by geometric rates. By eliminating export requirements and import costs the domestic production of bamboo products is on a course to become a major force in Florida agriculture. Bamboo will become the next cash crop for Florida and beyond.  In a collaboration with an Italian bamboo company and Florikan, a producer of NASA chosen controlled release fertilizer we have been able to refine and accelerate  the production, propagation and growth of certain bamboo  species. Due to the elegance of design and safety and efficiency of this controlled release fertilizer it is adaptable to the growth characteristics of bamboo. Application is necessary only once or twice per year or per growth cycle. Edible bamboo shoots in large volume can be achieved in 3 years with mature trunks available for harvest in 5 years.  The future for Florida citrus farmers need not be bleak as they will be the logical recipients of this technology as the demand for bamboo products increases and as Florida farmers and growers realize the vast potential of this “perfect” plant. Just as the original settlers in Florida recognized a natural resource and improved upon it to create a major industry, the new pioneers are poised to begin a new frontier for Florida agriculture. 

Barrett Demler and James Demler Sweetgrass Farms, Sarasota, Florida, USA Published in Fruit Juice Focus Stefan@fruitjuicefocus.com 

Stefan Worsley e contact@juicemarket.info
t +44 (0) 7711 564 219

 

Organic molecules on Mars

Organic molecules on Mars

On 6 August 2012, the Sample Analysis at Mars (SAM) instrument suite (1) arrived on Mars onboard the Curiosity rover. SAM’s main aim was to search for organic molecules on the martian surface. On page 1096 of this issue, Eigenbrode et al. (2) report SAM data that provide conclusive evidence for the presence of organic compounds—thiophenic, aromatic, and aliphatic compounds—in drill samples from Mars’ Gale crater. In a related paper on page 1093, Webster et al. (3) report a strong seasonal variation in atmospheric methane, the simplest organic molecule, in the martian atmosphere. Both these finding are breakthroughs in astrobiology.

Since NASA’s Curiosity rover landed on Mars in 2012, it has sifted samples of soil and ground-up rock for signs of organic molecules—the complex carbon chains that on Earth form the building blocks of life. Past detections have been so faint that they could be just contamination. Now, samples taken from two different drill sites on an ancient lakebed have yielded complex organic macromolecules that look strikingly similar to kerogen, the goopy fossilized building blocks of oil and gas on Earth. At a few dozen parts per million, the detected levels are 100 times higher than previous finds, but scientists still cannot say whether they have origins in biology or geology. The discovery positions scientists to begin searching for direct evidence of past life on Mars and bolsters the case for returning rock samples from the planet, an effort that begins with the Mars 2020 rover.

2018-07-25

NASA Statement on Possible Subsurface Lake near Martian South Pole

Science

Scientists have found evidence of a ‘lake’ on Mars

New evidence shows the presence of a large body of water, almost like a “lake,” one mile beneath the icy surface of Mars, according to a study published in the journal Science. They used data from Mars Express. If confirmed, this would be the largest body of liquid water found on Mars so far.Photo via @cnni

Far beneath the ice cap at Mars’s south pole lies a lake of liquid water—the first to be found on the Red Planet:

The view of Mars shown here was assembled from MOC daily global images obtained on May 12, 2003.

Credits: NASA/JPL/Malin Space Science Systems

Full image and caption

A new paper published in Science this week suggests that liquid water may be sitting under a layer of ice at Mars’ south pole.

The finding is based on data from the European Mars Express spacecraft, obtained by a radar instrument called MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding). The Italian Space Agency (ASI) led the development of the MARSIS radar. NASA provided half of the instrument, with management of the U.S. portion led by the agency’s Jet Propulsion Laboratory in Pasadena, California.

The paper, authored by the Italian MARSIS team, outlines how a “bright spot” was detected in radar signals about 1 mile (about 1.5 kilometers) below the surface of the ice cap in the Planum Australe region. This strong radar reflection was interpreted by the study’s authors as liquid water — one of the most important ingredients for life in the Universe.

“The bright spot seen in the MARSIS data is an unusual feature and extremely intriguing,” said Jim Green, NASA’s chief scientist. “It definitely warrants further study. Additional lines of evidence should be pursued to test the interpretation.”

“We hope to use other instruments to study it further in the future,” Green added.

One of those instruments will be on Mars later this year. NASA’s InSight lander will include a heat probe that will burrow down as far as 16 feet (5 meters) below the Martian surface. The probe, built by the German Aerospace Center (DLR), will provide crucial data on how much heat escapes the planet and where liquid water could exist near its surface.

“Follow the Water” has been one of the major goals of NASA’s Mars program. Water is currently driving NASA’s exploration into the outer solar system, where ocean worlds — like Jupiter’s moon Europa and Saturn’s moon Enceladus — hold the potential to support life. Even protoplanets like Ceres may explain how water is stored in rocky “buckets” that transport water across the solar system.

 Source : Inge Loes ten Kate Department of Earth Sciences, Utrecht University, Utrecht, Netherlands: i.l.tenkate@uu.nl in Science  08 Jun 2018: Vol. 360, Issue 6393, pp. 1068-1069

DOI: 10.1126/ science.aat2662

https://doi.org/10.1126/science.aat2662

Published By:

American Association for the Advancement of Science

Copyright & Usage:

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