Red ants build mounds of earth in fields, damaging crops and infiltrating electrical installations. In the US alone, the annual cost of damage caused by fire ants is estimated at $7 billion. [Anwar Attar / Shutterstock]
Scientists are urging national and EU authorities to take swift action against the rapid spread of the fire ant, a highly invasive species with the potential to cause major health and environmental damage.
A team of scientists from the Institute of Evolutionary Biology in Barcelona claim to have discovered 88 fire ant nests in Sicily, quite a jump from their origins in South America.
The species is now found worldwide, but this is the first time it has been found in Europe.
“The fire ant is considered one of the worst invasive exotic species and the fifth most costly in the world, affecting ecosystems, agriculture and human health,” explains the journal Current Biology in an article published this week.
In countries where it is abundant, such as Australia, China, and the United States, the insect causes significant environmental damage by attacking native species – including other ant species – and biting humans, causing a stinging sensation.
The spread of this species would have severe consequences for the climate, health and agriculture.
Ants build mounds of earth in fields, damaging crops and infiltrating electrical installations. In the US alone, the annual cost of damage caused by fire ants is estimated at $7 billion.
“Residents have informed us of frequent ant bites in the area since at least 2019, suggesting a prolonged presence” of the fire ant, the scientists stress.
While they are still unsure of the causes of the species’ arrival in Europe, it could be explained by the winds, or rather the importation of soil and plants, as the discovery is located near one of Sicily’s main freight ports, the Port of Augusta.
Contacted by Euractiv, French researcher Bernard Kaufmann, a specialist in biological invasions at the University of Lyon, explained that this discovery was widely expected.
“We’ve been waiting for this for 30 years; we thought one day it would come ashore, and we wouldn’t know what to do. But here we are,” he said.
Invasive exotic species are now considered one of the greatest threats to biodiversity. According to IPBES, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, the annual cost is more than $423 billion worldwide, four times more than in the 1970s.
The consumption of blue crabs recommended by Italy’s government members to halt the invasive species’ spread in the Mediterranean complies with the EU food rules, the European Commission confirmed to EURACTIV – but warns the feast may not last for
From Portugal to Bordeaux
But this is just the beginning, according to the scientists.
They say the ants could quickly spread across the connected regions of southern Europe along the Mediterranean coast.
Research shows that if the spread is not stopped, most European countries will be affected by 2050, with high concentrations in urban areas due to higher temperatures.
“Half of Europe’s urban areas have already adapted and […] the global warming expected on current trends will favour the expansion of this invasive ant,” they predict, admitting their “concern” for the future.
But Kaufmann is more cautious.
“The researchers only took temperature and land use into account in their modelling, but things are a bit more complex,” he said.
“Nevertheless, it is certain that these ants can now establish themselves in all warm regions of Europe, from Portugal and Spain to Bordeaux in France. With global warming, this will extend to more northerly regions,” he admitted, warning of the species’ high colonisation capacity.
EU legislation
At the EU level, a Regulation adopted in 2014 sets out rules for the prevention, minimisation and mitigation of the adverse impacts of invasive alien species (IAS).
It contains a list of more than 80 species of concern that are prohibited from being imported, transported, marketed, used, cultivated or introduced into the environment. In the event of an invasion, the law requires states to eradicate these species within three months.
In anticipation of this, scientists have managed to get the fire ant Solenopsis Invicta added to the list in 2022.
“If the European regulations are applied quickly, it is still possible to eradicate this species and prevent it from spreading across Europe. But we need to act fast,” said Kaufmann.
Since Sicily is an island, the speed of its spread can be limited.
In Italy, “eradication plans are underway,” the Corriere della Sera newspaper reported.
In Spain, scientists call for “coordinated detection efforts” and surveillance that “should be extended to a larger geographical scale”.
Everyone, including the general public, should report sightings, as the species is atypical in several respects (stinging, mounds of earth), they added.
In France, a portal has been set up for reporting encounters with invasive alien species.
For Kaufmann, the question is whether the ant is already present elsewhere. Because “when it does take hold, it does so on a massive and irreversible scale”, he warns.
How can Metarhizium be used to address pests and diseases?
Sihle Nakombe is a lab technician from CABI’s office in Zambia. She joined CABI in January 2023. Earlier this year, she visited the CABI labs in Egham, UK, to get training on Metarhizium. This naturally occurring fungus can control insect pests with low environmental and human health effects.
Sihle grew up in Mazabuka, a small town in the Southern Province of Zambia. Mazabuka is known for producing sugar branded as Zambia Sugar, the largest sugar manufacturing company in Zambia. She holds a bachelor’s degree in microbiology from The University of Zambia. During this time, Sihle became involved in a Stirring Steam for Science Technology Engineering Mathematics and with the Zambian Women in Agriculture Research and Development organisation.
Participating in various activities during university opened Sihle’s mind to the different aspects of agriculture. Sihle’s focus at CABI is on the biological control of pests affecting small-scale farmers in Zambia, using fungus and natural enemies. In the future, Sihle hopes to further her research in integrated pest management (IPM) using biological control.
Here, we learn more about Sihle and her work on Metarhizium.
What is Metarhizium?
Metarhizium is a genus of entomopathogenic fungi Clavicipitaca.Metarhizium is a naturally occurring fungus that can control insect pests with low environmental and human health effects. The fungus can be very host-specific, meaning it does not harm other organisms, such as insects, animals and humans.
What are you learning about Metarhizium at CABI’s labs in Egham?
My learning focused on the mass production of Metarhizium rileyi and some laboratory techniques such as germination tests, hemocytometer count and contamination tests.
Why is research on Metarhizium important for the work of PlantwisePlus?
Within CABI PlantwisePlus, we aim to reduce the use of highly hazardous pesticides. One way we are doing this is by promoting the use of biological control. Metarhizium is one biological control product used worldwide to control various insect pests. It can be produced in large quantities artificially, making it suitable to be developed into a commercial product.
Moreover, it has low environmental and human health effects. And insects do not build up resistance to it. Within PlantwisePlus, we aim to support developing countries to produce their own biological control so that subsistence farmers can afford to use them.
How is Metarhizium used in the field?
We are currently working on how it can be used in the field by producing the best formulation from the lab and then to the field. Metarhizium can be applied in the same way sprayers apply chemical pesticides.
In addition to this, Metarhizium can also be applied as a powder. In Zambia, we are looking at using a basic formulation of sand and fungus to apply to the whorls of the maize plants, as this is where the invasive fall armyworm (Spodoptera frugiperda) can be found, along with sprayable formulations.
Can Metarhizium be used to address pests and diseases?
Yes, it can be used to address pests and diseases. Metarhizium is naturally found in some parts of Zambia and is known to kill fall armyworm. As this particular fungus is a native strain, it is naturally adapted to the environmental conditions of Zambia, making it a potential successful biocontrol product. Although, Metarhizium is an insect pathogen and generally does not control diseases.
What motivated you to work in science and development?
I have always had a great passion for science since an early age. As I grew older, the problems affecting the economy in Zambia were apparent. I, therefore, wanted to work in science and development to bring change and innovative technologies to address these problems. Not just in Zambia, but also in vulnerable nations across the globe.
What does a typical day look like in the lab?
A typical day in the lab begins with disinfecting the surfaces. Then, I carry out bioassays for the fungus and virus if needed. My focus then turns to conducting some quality control tests with fungus, checking on the rearing of fall armyworm and ttomato leafminer (Phthorimaea absoluta). The laboratory apparatus and the environment I work in must always be clean.
What do you like most about working for CABI?
Working at CABI has enabled me to improve my capacity-building skills, strengthening and developing my skillset to thrive in a fast-changing world. As well as this, my laboratory skills have been further developed, allowing me to enhance my understanding of the biological control of insect pests. Moreover, I have further increased my experience working with farmers, which is a necessary skill to provoke change at a grassroots level.
What areas of future research do you wish to investigate?
I wish to investigate the biological control of insects further to help suppress the population of pests to make them less damaging. Furthermore, I would love to broaden my understanding of the PlantwisePlus programme to support small-scale farmers using fewer pesticides to control pests.
Jo Ruane and Niall Farrelly provide an overview of ADAPTForRes, a new research project coordinated by Teagasc, which is an all island research collaboration aimed at strategies to increase the resilience in Irish forests.
Endophytes are fungi which have co-evolved with plants and grow inside plant tissue without causing any negative consequences to the host. Endophytic fungi can be beneficial to plants and promote plant growth by producing phytohormones, which can promote root and shoot formation and/or facilitate better nutrient update. Such hormones can also have a protective effect by acting as biological control agents and increase the plants resilience to environmental stresses. This is achieved by the production of antimicrobial and antioxidant like compounds which act to provide the tree with a pest and pathogen like defence mechanism.
Specific species of fungal endophytes have been known to enhance the thermal and drought tolerance of the trees by increasing the rate of photosynthesis and water retention under water limited conditions. The capability for increasing stress tolerance is anticipated to play an important role in the management of plants that are used as crops, albeit for food or timber in the future. In addition, recent studies have demonstrated the role of endophytic fungi as a bio-inoculant to enhance protection against disease.
The presence and composition of endophytes in habitats can tell us a lot about the conditions of a crop on a given site. In their endophytic phase, they work to provide a mutually beneficial symbiotic relationship with the host plant without causing any negative consequences. However, endophytes can also exist as latent pathogens which may become active under certain environmental conditions. If we understand what type of endophytes exist, it may prove to be a useful early indication if there are potential disease causing endophytes present in an ecosystem before they become problematic.
Fungal endophytes as early warning system
Climate change will create uncertainties for how forest ecosystems will adapt and alter our strategy to manage and protect our forests. We must be vigilant to limit the introduction of novel invasive fungal pathogens and have strategies to limit the spread and effect of existing diseases. It is uncertain whether warmer conditions associated with climate change will increase the prevalence of certain pathogens by providing conditions which will allow them to proliferate. Early warning systems such as monitoring are good strategies to detect diseases early on, before they become fully established, thus there is a greater chance of attaining a successful outcome for their control.
ADAPTForRes, a new research project coordinated by Teagasc, is an all island research collaboration aimed at strategies to increase the resilience in Irish forests. Changing climate conditions in some cases may result in a positive outcome for forests, by promoting increased growth (e.g. longer growing season) or bring negative effect consequences depending on how well the tree species can adapt to changing conditions.
It is hoped AdaptForRes will increase knowledge on endophyte diversity in Irish forests, including pathogenic endophytes, of Irish trees. The project hopes to provide innovative ways for detecting endophytes in Irish Forests. The goal is to explore ways of improving on the early warning systems that we have in place.
ADAPTForRes – Sampling Endophytic fungi
Flavio Storino, who is a PhD student, based at University College Dublin, is conducting the study on endophytic fungi in Irish forests. The research will demonstrate a baseline for fungal foliar diversity in trees at specific locations throughout Ireland. This work essentially creates a template for the development of a future surveillance network, which will enable foresters to ascertain the presence of pathogens in particular areas.
This task involves determining fungal endophyte populations in leaf samples from three different tree species in Ireland, both native and non native. These are Sessile oak, Scot’s pine and Sitka spruce.
Figure 1: Flavio Storino sampling sessile oak leaves for endophyte analysis
How do we determine endophytic populations?
Leaf samples are collected and the endophytic fungi are then extracted from the leaves, grown in growth media, isolated and genetically identified. This could have potential as a novel way to detect the presence of disease causing fungi. Essentially, this work is a preliminary study to see if such methods are robust to utilise as part of a surveillance efforts for Irish forests.
Figure 2: Needle samples placed on growth media to promote endophyte growth
Once pure cultures of the fungi have been isolated, the DNA is extracted and segments are amplified by PCR testing (polymerase chain reaction). This is a technique for rapidly producing or amplifying millions to billions of copies of a specific segment of DNA.
Figure 3: Endophyte proliferation following incubation
A technique known as barcoding allows the isolates to be further studied. These DNA barcodes can be compared to a reference library to provide a precise identification. An existing database of reference material has been compiled through previous research studies for example, Gembank.
Evaluation of the diversity of fungi out using statistical analysis (incl. diversity indices-which is a way to give a numerical value to how diverse an ecological community is). Overall, this research is invaluable and provides the first study of the population genetics of forest endophyte on the island of Ireland.
This article is an overview of forest protection measures within the ADAPTForRes project. The project is funded by the Department of Agriculture, Food and the Marine. The authors would like to thank Flavio Storino for demonstrating the field and laboratory techniques involved in the study.
For more forestry related material. Visit the Teagasc Forestry Development Department webpage.
by Marcin Behrendt, Nicolaus Copernicus University
TEM micrographs of silver nanoparticles from F. culmorum strain JTW1 (A–C) and SAED. Credit: Frontiers in Microbiology (2023). DOI: 10.3389/fmicb.2023.1125685
They are used as medicines, drug carriers and to combat microbes in hospitals, destroy plant pathogens and reduce the amount of traditional fertilizers used in agriculture—nanoparticles are taking over medicine and the agri-food industry.
Nanoparticles are tiny structures up to 100 nanometers in size. They are characterized by different physical and chemical properties and biological activity than their larger material counterparts.
“When the starting material on a micro-scale with a specific surface area is broken down to nano size, i.e. into smaller particles, its surface area will increase many times. And it is the ratio of surface to volume that results in the unique properties of nanoparticles,” explains Prof. Mahendra Rai from Sant Gadge Baba Amravati University in India.
Nanoparticles can be mainly organic or inorganic. Among the organic ones, we can distinguish liposomes, micelles, and dendrimers.
“Liposomes are vesicles made of a phospholipid bilayer with free space inside, in which you can put, for example, a drug and precisely deliver it to the target place in the body because the liposomes will disintegrate in the acidic environment of the tumor and release the drug in it,” says, prof. Patrycja Golinska from the Department of Microbiology at the Faculty of Biological and Veterinary Sciences NCU.
“Among inorganic nanoparticles, we can distinguish nanoparticles of metals such as silver, gold, titanium, copper, metal oxides (e.g. zinc oxide) and semi-metals (metalloids) such as silica, selenium, and aluminum. At Nicolaus Copernicus University, we focused mainly on metal nanoparticles. So far, we have mostly biosynthesized silver and gold nanoparticles. In recent years, we have also biosynthesized nanoparticles of zinc, copper, and magnesium oxides.”
Nanoparticles can be obtained in various ways, but in recent years, the so-called green synthesis (biological synthesis or biosynthesis) has attracted increasing interest in nanotechnology.
“It is environmentally friendly. In biological synthesis, unlike chemical or physical synthesis, the production of nanoparticles does not use toxic compounds and does not consume large amounts of energy”, says Prof. Rai.
In addition, after the production of nanoparticles in a chemical or physical way, they still need to be stabilized, i.e. “coated” with other chemical compounds, which are usually also toxic. The point is that the nanoparticles do not aggregate, i.e. do not combine with each other into structures of larger sizes and do not lose their reaction surface and thus their unique properties.
Green nanotechnology
Biologists from the Nicolaus Copernicus University in Toruń became interested in biosynthesis, i.e. the synthesis of nanoparticles by microorganisms such as fungi and bacteria, as well as by algae and plants. During the visit of Prof. Rai in Poland, scientists focused on mycosynthesis, i.e. the synthesis of nanoparticles using fungi.
“As part of the project, which Prof. Rai carried out at the Nicolaus Copernicus University, we synthesized silver nanoparticles using fungi, mainly of the genus Fusarium, which infect plants, including cereals, but also from other genera like Penicillium, which develop e.g. on tangerines and lemons,” says prof. Golinska. “In such production, no toxic compounds are used and no toxic waste is produced.”
The advantage of fungi over other microorganisms in the synthesis of nanoparticles is that they produce a large number of various metabolites, including many proteins, including enzymes, and many of these substances can be involved in the reduction of silver ions to nanosilver.
Applications
Nanotechnology can be used in the most important areas of human life: medicine, agriculture and the packaging industry, and food storage. Nanoparticles are highly active against various microorganisms.
They fight pathogenic microbes very well and inhibit their spread, which can be used to produce various surfaces and materials in hospitals, such as masks with a nanosilver filter, which were created during the COVID-19 pandemic. They are effective against bacteria that are resistant to commonly used antibiotics. Silver nanoparticles also have anti-cancer properties.
“Nanomaterials are smart, they can be administered, for example, intravenously, but they work at the target site, i.e. in a cancerous tumor, and not like chemotherapy, which is distributed throughout the body at the same time destroying both abnormal and healthy cells,” explains Prof. Rai. In the case of nanoparticles, we can use targeted therapy, in which the anti-cancer drug will be released only at the site of the tumor. Nanoparticles themselves can be a drug, and also a drug carrier.
In agriculture, nanotechnology is used in three aspects. The first is the early detection of plant pathogens before the first symptoms of plant disease appear. The electronic nose is a technology that we do not deal with at the moment, but thanks to the use of nanomaterials such as nanowires or nanorods of zinc oxide in this device, it detects volatile substances produced by pathogenic fungi.
“Other types of nanobiosensors detecting the DNA of plant pathogens can also be used,” says Prof. Golinska. “Thanks to this, appropriate agrotechnical treatments can be applied before we see the symptoms of plant infestation, e.g. discoloration, raids or necrosis of leaf blades.”
The second aspect is the use of a solution of nanoparticles to directly combat pathogens that have already developed on plants. Such nanoparticles usually act at much lower concentrations than chemical fungicides, so their concentration in the environment is also much lower compared to commonly used fungicides.
The third area of application of nanomaterials in agriculture is the delivery of nutrients to plants. As in medicine, nanomaterials themselves can be a nutrient or a carrier containing a nutrient that can be released in a controlled manner. When farmers use traditional fertilizers, they deliver a huge amounts of them to the fields in a short time, which plants are unable to use and a large part of them penetrates deep into the soil to groundwater and, consequently, to water reservoirs (surface water).
This adversely affects the aquatic environment leading to its eutrophication. Excessive fertilization also harms soil microorganisms and leads to the so-called. “Soil fatigue,” i.e. a constant imbalance in the content of nutrients, which negatively affects the size of crops. Using nanoencapsulation, i.e. placing nanoparticles that are nutrients for plants in capsules or matrices, you can apply these nutrients by foliar or soil application.
“The biggest advantage of this solution is the release of nutrients in a controlled, slow and constant way. This is an element of sustainable development, which is extremely important nowadays,” says Prof. Rai.
Friendly fungi
Prof. Rai came to Poland for two years thanks to a scholarship he received from the Polish National Agency for Academic Exchange (NAWA). Under the proposed project, “Development of new environmentally-friendly and biologically active nanomaterials” together with a team consisting of Dr. hab. Patrycja Golińska (prof. of NCU), Dr. Magdalena Wypij, and Ph.D. student Joanna Trzcińska-Wencel, dealt with the production of nanocomposites based on pullulan and silver nanoparticles (AgNPs) for combating various microorganisms.
“Pullulan, a natural biodegradable polymer, was biosynthesized using fungi (Aureobasidium pullulans) and combined with silver nanoparticles, produced by green synthesis using mold fungi, which I mentioned earlier,” explains Prof. Golińska. “We created films, i.e. thin and flexible foils, encrusted with silver nanoparticles. We tested these films, for example, to combat pathogens responsible for wound infections or those that develop in food, such as Listeria monocytogenes or Salmonella sp., i.e. de facto to extend the shelf life of food.”
Pullulan incorporated with silver nanoparticles presents beneficial properties and therefore could be used, for example, in the production of food packaging or dressings which accelerate the healing of wounds, protecting them against the development of infection. “When we have more extensive wounds, e.g. burns, they are highly exposed to the development of infection,” explains Prof. Golińska. “Securing such a place with a biodegradable polymer with an agent inhibiting the development of pathogens will significantly accelerate wound healing.”
The team intends to patent a method for obtaining pullulan-based nanocomposites and releasing nanoparticles from the film.
Two research papers were published in the journal Frontiers in Microbiology during the professor’s visit, namely “Biogenic nanosilver bearing antimicrobial and antibiofilm activities and its potential for application in agriculture and industry” and “Superior in vivo wound-healing activity of mycosynthesized silver nanogel on different wound models in rat.”
Another two, “Biofabrication of novel silver and zinc oxide nanoparticles from Fusarium solani IOR 825 and their potential application in agriculture as biocontrol agents of phytopathogens, and seed germination and seedling growth promoters” and “Pullulan-based films impregnated with silver nanoparticles from Fusarium culmorum strain JTW1 for potential applications in food industry and medicine” were published just after Prof. Rai left Poland. The papers were published in Frontiers in Chemistry and Frontiers in Bioengineering and Biotechnology.
More information: Joanna Trzcińska-Wencel et al, Biogenic nanosilver bearing antimicrobial and antibiofilm activities and its potential for application in agriculture and industry, Frontiers in Microbiology (2023). DOI: 10.3389/fmicb.2023.1125685
Swapnil Gaikwad et al, Superior in vivo Wound-Healing Activity of Mycosynthesized Silver Nanogel on Different Wound Models in Rat, Frontiers in Microbiology (2022). DOI: 10.3389/fmicb.2022.881404
Joanna Trzcińska-Wencel et al, Biofabrication of novel silver and zinc oxide nanoparticles from Fusarium solani IOR 825 and their potential application in agriculture as biocontrol agents of phytopathogens, and seed germination and seedling growth promoters, Frontiers in Chemistry (2023). DOI: 10.3389/fchem.2023.1235437
Magdalena Wypij et al, Pullulan-based films impregnated with silver nanoparticles from the Fusarium culmorum strain JTW1 for potential applications in the food industry and medicine, Frontiers in Bioengineering and Biotechnology (2023). DOI: 10.3389/fbioe.2023.1241739
By Dusty Sonnenberg, CCA, Field Leader, a project of the Ohio Soybean Council and Soybean Check-off
In his years studying soils, Adam Daugherty, NRCS District Conservationist, Coffee County Tennessee, has come to the conclusion that soils have latent potential just waiting to be developed and manifest. “We don’t just want to conserve our soils when we can restore and help improve them,” said Daugherty. “The rejuvenation of your soil does not start with the implementation of principles, but rather the commitment to understanding ecological functions. You need to know why before how. The ingredients include the sun, soil, plants, and you.”
Daugherty believes that while no-till production is a good step, the implementation of no-till practices alone will not rejuvenate the soil. “Biologically, no-till was bacteria dominated. That biology is presently out of balance, and in many places the overall ecosystem functions are low,” said Daugherty. “Minus a lot of erosion and a little diesel, no-till production has mirrored conventional tillage. In the bigger picture, the logistics of soil rejuvenation and feeding the global population are not going to be met with a 15’ no-till drill.”
“There is the potential in a rejuvenated, healthy, functioning soil health management system to make money, clean the water, and restore resources,” said Daugherty.
The potential of the soil resource and its resiliency depend on five things, including moisture, temperature, pests, structure and the organic nutrient pool. To help reach that potential, Daugherty suggests keeping the soil covered. He likens it to a house that must be protected. He also suggests having living plants capturing sunlight and driving soil functions. “Having plant diversity creates synergistic collaborations within the soil biology,” said Daugherty. “It takes moisture to manage moisture. We cannot manage precipitation, only evaporation. There are more days with the potential to lose moisture than there are to gain moisture. Keeping the soil covered helps to manage moisture.”
Living crops allow for the management of moisture. “Why would we pray for rain if we have not prepared a place for it to fall,” asked Daugherty. “Fallow ground does not mimic any natural principle.” Having a growing crop breaks up rain drops as they fall, both slowing the speed and allowing the smaller droplets to infiltrate rather than run off. Plants also capture energy from sunlight and shade the soil to reduce evaporation and erosion.
“Bare soil creates energy imbalances,” said Daugherty. “We waste money in the space between plants. Plant biomass shades the soil and helps moderate the soil temperature. Soil temperature is important to microbial life.”
“The sun is the energy source that is captured by the plants. To rejuvenate the soil we need a diversity of plants.”
“Soil health is not complicated. Anytime there is not a living plant, the soil is degrading. We need to capture the energy from the sun to drive the system,” said Daugherty. “Nature wants to stabilize the carbon to nitrogen ratio in the soil. We farm in a high C:N ratio. The soil is naturally designed for consumption and the flow of energy.”
04 Sep 2023 — Researchers have identified a species of fungus that transforms patulin, a dangerous mycotoxin sometimes found in fruits, into less toxic byproducts.
Patulin is a harmful mycotoxin produced by fungi typically found in damaged fruits, including apples, pears and grapes. The researchers say that the latest findings provide important insights into the degradation mechanisms for patulin found in nature and can lead to new ways of controlling patulin toxicity in our food supplies.
Patulin contamination Patulin (C7H6O4), a mycotoxin produced by several types of fungi, is toxic to various life forms, including humans, mammals, plants and microorganisms.
In particular, environments lacking proper hygienic measures during food production are susceptible to patulin contamination. Many of these fungi species grow on damaged or decaying fruits, specifically apples and even contaminate apple products, such as apple sauce, apple juice, jams and ciders.
Responsible for various health hazards, including nausea, lung congestion, ulcers, intestinal hemorrhages and even more severe outcomes, such as DNA damage, immunosuppression and increased cancer risk, patulin toxicity is a serious concern worldwide. As a result, many countries have imposed restrictions on the permitted levels of patulin in food products, especially baby foods, as infants are more vulnerable to the effects of patulin.
Treatment of patulin toxicity includes oxygen therapy, immunotherapy, detoxification therapy and nutrient therapy. However, as prevention is often better than cure, scientists have sought efficient ways to mitigate patulin toxicity in food products.
Keeping patulin toxicity in check To this end, a research team, including Associate Professor Toshiki Furuya from Tokyo University of Science (TUS) in Japan, recently screened for soil microorganisms that can potentially help keep patulin toxicity in check.
Patulin is a harmful mycotoxin produced by fungi typically found in damaged fruits, including apples.The team cultured microorganisms from 510 soil samples in a patulin-rich environment, looking for those that would thrive in the presence of the toxin.
Next, in a second screening experiment, they used high-performance liquid chromatography (HPLC) to determine the survivors that were most effective in degrading patulin into other less harmful chemical substances. Accordingly, they identified a filamentous fungal (mold) strain, Acremonium sp. or “TUS-MM1,” belonging to the genera Acremonium, that fit the bill.
The team then performed various experiments to shed light on the mechanisms by which TUS-MM1 degraded patulin. This involved incubating the mold strain in a patulin-rich solution and focusing on the substances that gradually appeared inside and outside its cells in response to patulin over time.
Transforming cells One important finding was that TUS-MM1 cells transformed any absorbed patulin into desoxypatulinic acid, a compound much less toxic than patulin, by adding hydrogen atoms to it.
“When we started this research, only one other filamentous fungal strain had been reported to degrade patulin,” comments Dr. Furuya. “However, no degradation products had ever been identified before the present study. To our knowledge, TUS-MM1 is the first filamentous fungus shown to be capable of degrading patulin into desoxypatulinic acid.”
Moreover, the team found that some of the compounds secreted by TUS-MM1 cells can also transform patulin into other molecules. By mixing patulin with the extracellular secretions of TUS-MM1 cells and using HPLC, they observed various degradation products generated from patulin.
Notably, experiments on E. coli bacterium cells revealed that these products are significantly less toxic than patulin itself. Through further chemical analyses, the team showed that the main agent responsible for patulin transformation outside the cells was a thermally stable but highly reactive compound with a low molecular weight.
Overall, the findings of this study take the researchers a step closer to efficient solutions for controlling the levels of patulin in food.
Dr. Furuya further speculates: “Elucidating the pathways via which microorganisms can degrade patulin would be helpful not only for increasing our understanding of the underlying mechanisms in nature but also for facilitating the application of these organisms in biocontrol efforts.”
