Tag Archives: parasitic

Uh Oh, Scientists Figured Out How to Grow Terrifying Parasitic Mushrooms in the Lab

Just in time for Halloween, scientists in Korea say they’ve found a better way to grow an insect-destroying mushroom in the lab. Their work could make studying these fungi easier, which is important, since they and the chemicals they produce may actually have medicinal uses for humans, creepy as they are.

The fungi is known as Cordyceps. Members of this genus, along with a related but distinct genus called Ophiocordyceps, are parasitic, usually feeding on insects and other arthropods. These fungi will invade and often kill their hosts, though not before using them as fuel to grow their fruiting bodies (technically, this is the part of the fungi that we call the mushroom) and release new infectious spores into the world to start the process all over again. Some members of Ophiocordyceps are also known for “zombifying” their ant hosts by manipulating their behavior before death to ensure their optimal survival.

As horrifying as their way of life is, some members of Cordyceps are considered food in parts of Asia. They’ve also been used in traditional Chinese medicine and more recently are being sold as supplements (supplements of any kind, it should be noted, have little quality control and aren’t necessarily harmless). And early research has suggested that Cordyceps produce chemicals that could have beneficial health effects, particularly a compound called cordycepin. Some studies have indicated, for instance, that cordycepin might have anti-viral or cancer-fighting properties.

This research has largely come from animal or lab studies, though, meaning it will take a lot more evidence in humans to confirm any potential benefits. These experiments and any eventual widespread use of Cordyceps will also require having ample supplies of the fungi or their compounds, and that’s a challenge. Though these fungi are found throughout the world, they’re hard to find and harvest from the wild. There are now ways to cultivate them in the lab, but the current methods only yield low amounts of healthy Cordyceps or cordycepin, making them hard to scale up.

Cordyceps militaris
Photo: charnsitr (Shutterstock)

Researchers at Chungbuk National University tried to improve on these methods, which usually use brown rice as the growth medium. They theorized that these mushrooms would grow better on richer sources of protein—namely, insects. They also guessed that their diet would affect how large the fungi grew and how much cordycepin they produced, so they tested out different types of insects. These insect nurseries were kept growing for two months before the researchers harvested the Cordyceps. The team’s findings, published Wednesday in Frontiers in Microbiology, suggests that their insect theory was right on the money.

Cordyceps grown on edible insects contained approximately 100 times more cordycepin compared to Cordyceps on brown rice,” said study author Mi Kyeong Lee, a professor at Chungbuk, in a statement from Frontiers.

As expected, though, there were differences in how the insect food affected their growth. The fungi were most plentiful when they fed on mealworms and silkworm pupae, for instance. But they actually produced the most cordycepin when they fed on Japanese rhinoceros beetles. The team’s work also indicates that it was the fat content of the insects, not their protein, that predicted how much cordycepin the mushrooms produced. The rhinoceros beetles were especially full of a type of fat called oleic acid, and once the team introduced oleic acid to a low-fat insect feed, the Cordyceps’ production of cordycepin rose as well.

“The cultivation method of Cordyceps suggested in this study will enable the production of cordycepin more effectively and economically,” Lee said.

While these scientists may have found an improved method of growing Cordyceps in the lab, you probably shouldn’t expect mass production just yet. The authors note that churning out insects on an industrial scale isn’t easy, either. So if these freaky fungi do turn out to be medically valuable, there’ll be more challenges ahead in developing them for mass use. That said, there is at least one research team at Oxford University actively studying a modified version of cordycepin as a cancer drug in early human trials.

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These newly-engineered parasitic worms can kill cancer cells

Back in November of 2021, we brought you news of scientists developing a cancer screening test using genetically engineered roundworms to detect early signs of pancreatic cancer from just a drop of urine. 

Now, researchers from Osaka University have discovered that a particular kind of microscopic worm known as nematodes can kill cancer cells, according to a press release by the institution published last month. To achieve this, the worms must be coated with hydrogel-based “sheaths” that can be further engineered to transport functional cargo (cancer-killing substances).

A marine-dwelling worm that seeks out cancer cells

One of these types of nematodes is the Anisakis simplex, a microscopic marine-dwelling creature that is particularly fond of cancer cells.

“Anisakis simplex has been reported to sense cancer, potentially by detecting cancer “odor,” and to attach to cancerous tissues,” Wildan Mubarok, first author of the study, said in the statement. “This led us to ask whether it could be used to deliver anti-cancer treatments directly to cancer cells within the human body.”

The researchers decided to investigate a system for applying hydrogel sheaths to nematodes in order to create a gel-like layer all over their bodies that would protect them against the cancer-killing substances they would be equipped to carry. The end results were nematodes fitted with a suit about 0.01 mm thick. Even cooler, the whole process only took 20 minutes.

“The results were very clear,” says Shinji Sakai, senior author of the study. “The sheaths did not in any way interfere with the worms’ survival and were flexible enough to maintain the worms’ motility and natural ability to seek out attractive smells and chemical signals.”

Anti-cancer agents delivered directly to cancer cells

Next, the researchers experimented with applying anti-cancer agents to the nematodes. Typically, this may be harmful to the parasitic worms, but in this case, the creatures were protected by their hydrogel armor. The scientists found that the newly-engineered worm could then transport and deliver the anti-cancer agents in order to kill cancer cells in vitro.

“Our findings suggest that nematodes could potentially be used to deliver functional cargo to a range of specific targets in the future,” states Mubarok. “Given the adaptability of the hydrogel sheaths, this worm-based delivery system holds promise not only for delivering anti-cancer drugs to tumor cells in patients, but it also has potential applications in other fields such as delivering beneficial bacteria to plant roots.”

The research is still in its early stages and may encounter several issues during development. There is the fact that many people will not want parasitic worms in their systems. There is also the issue of how to control the creatures once they have been administered to the human body. Still, in terms of cancer treatments, it offers hope of a new and effective solution.

The study was published in the journal Science Direct.

Abstract:

Engineering the surfaces of biological organisms allows the introduction of novel functions and enhances their native functions. However, studies on surface engineering remained limited to unicellular organisms. Herein, nematode surfaces are engineered through in situ hydrogelation mediated by horseradish peroxidase (HRP) anchored to nematode cuticles. With this method, hydrogel sheaths of approximately 10-μm thickness are fabricated from a variety of polysaccharides, proteins, and synthetic polymers. Caenorhabditis elegans and Anisakis simplex coated with a hydrogel sheath showed a negligible decrease in viability, chemotaxis and locomotion. Hydrogel sheaths containing UV-absorbable groups and catalase functioned as shields to protect nematodes from UV and hydrogen peroxide, respectively. The results also showed that hydrogel sheaths containing glucose oxidase have the potential to be used as living drug delivery systems for cancer therapy. The nematode functionalization method developed in this study has the potential to impact a wide range of fields from agriculture to medicine.

 



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Annoying Cat Parasite Has Again Been Linked to Psychotic Episodes, But Only in Men

A ubiquitous parasite estimated to infect millions of people around the world has been linked with schizophrenia and a host of neurological disorders, but the evidence hasn’t always been clear.

 

While there are a number of studies linking the ‘mind-altering’ parasite Toxoplasma gondii with altered behavior or weird patterns in human activity, there are also data debunking the association.

Now, a new study led by first author and psychiatry resident Vincent Paquin from McGill University in Canada could help to explain this parasitic paradox – while going some way to identifying where the apparent dangers of T. gondii may actually lie.

In addition to contaminated food or water (including undercooked meat), the protozoan parasite T. gondii can be transmitted to humans through exposure to feces from an infected domestic cat, with a study in 1995 first observing a link between cat ownership in childhood and risk of mental illness later developing in adulthood.

However, other studies since have failed to replicate the cat ownership link, suggesting there might be more to the association than simply owning a cat.

“Domestic cats generally become infected with the parasite by feeding on rodents, and will only be contagious during the days or weeks that follow,” Paquin and his co-authors write in their new paper.

 

“Hence, specifying whether the cat was known to hunt rodents might provide a better proxy for probable exposure to T. gondii compared to cat ownership alone.”

In other words, as Paquin explains, cats themselves do not guarantee parasitic exposure, but rodent-hunting cats (i.e., cats that are allowed outside, as opposed to indoor-only pets) would probably be more likely to come into contact with T. gondii in the outdoor environment.

Hypothetically speaking, they might then transmit the infection to children, who could go on to develop psychological issues in adulthood, as identified in some studies, potentially through effects on the immune system.

To examine this hypothetical chain of transmission, the researchers surveyed approximately 2,200 participants in Montreal, asking them questions about childhood cat ownership, and measuring their frequency of psychotic experiences, alongside other questions about their personal history, such as how much they moved house during childhood, experiences with head trauma, history of smoking, and so on.

In analyzing the responses, the team observed that male participants who had owned a rodent-hunting cat during childhood showed an increased risk of having psychotic experiences in their adulthood; female respondents did not have the same link.

 

People who owned indoor-only cats during childhood (or no cat at all) did not show the same increased risk, which the team said was “consistent with our hypothesis based on the life cycle of T. gondii as the putative mechanism of this association”.

However, other factors captured in the survey also seemed to influence the respondents’ risk for psychotic experience, including smoking, frequency of residential moves in childhood or adolescence, and a history of head trauma, which Paquin says suggests “synergistic effects of these factors”, beyond just parasitic infection alone.

While the study has a number of limitations – including that all the data from the survey were self-reported – the team says their findings illustrate the importance of examining interactions among different kinds of environmental exposures, which may in the future help us to identify with greater accuracy where problems from T. gondii exposure are more likely to arise.

“These are small pieces of evidence but it’s interesting to consider that there might be combinations of risk factors at play,” Paquin told Medscape Medical News.

“And even if the magnitude of the risk is small at the individual level, cats and T. gondii are so present in our society that if we add up all these small potential effects then it becomes a potential public health question.”

The findings are reported in Journal of Psychiatric Research.

 



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Dear Doctor: Do people need regular ‘dewormings’ to prevent parasitic infections?

DEAR DR. ROACH: One of my New Age friends claims that our food (meat, fish and even highly processed food) is full of unspecified parasites, therefore a regular cleansing of the digestive system is desired. Wormwood has been mentioned as a treatment. Is there any truth to it? Do we need regular “dewormings”? — K.O.S.

ANSWER: Parasitic infections are uncommon in the United States and Canada. Many parasites diagnosed in the U.S. are brought from international travel. Others, such as Giardia, are found in contaminated (untreated) water. Foodborne parasitic infections, such as tapeworms, can be found in beef, pork and fish, but these are rare. Parasitic infections from highly processed foods would be vanishingly rare, which may be the best thing you can say about consuming ultraprocessed foods.

Symptoms of intestinal parasitic infections may include nausea and weight loss. Vitamin B12 deficiency is common with the fish tapeworm. People may notice passing part of the worm in the stool.

Wormwood is used as a flavoring in alcoholic beverages (Absinthe) and is said to be hallucinogenic, although the dose needed for that toxicity is much higher than one can drink without getting very ill from the alcohol. The name does come from ancient descriptions of the use of Artemisia absinthium as a treatment for worms. Interestingly, a recent trial did show that wormwood extract is effective for schistosomiasis in Africa, which is caused by a type of worm that is not found in the U.S.

Medication to treat worms is not necessary and potentially toxic and therefore not recommended. Since these infections are rare, neither screening nor prophylactic treatment is needed.

DEAR DR. ROACH: I am 79 years old, male and in good shape. The only medication I take is 20 mg of Lipitor daily. Approximately five years ago, I fell off a small ladder. The fall was caused because I lost my balance. From that time on, my balance has worsened. I notice that when I lose my balance, most of the time I fall backward. I consulted an ear, nose and throat specialist, whose results came back negative. I met with a neurologist, who arranged for an MRI of my brain, which came back normal. Have you any suggestions? — G.

ANSWER: Balance problems are extremely common in older adults, and often, a single cause cannot be found. Falls happen in about a third of older adults in the community every year.

A comprehensive evaluation is appropriate. This includes not only the studies of balance and strength that I’m sure your ENT and neurologist did, but a vision assessment, checking the heart and the blood pressure both standing and laying down, a foot inspection and review of medications (Lipitor is NOT one of the many drugs commonly associated with falls). A vitamin D blood level may be useful, with supplementation for those with low levels.

If the evaluation yields no identifiable cause for falls, my personal practice is to refer to physical and/or occupational therapy. These professionals have expertise in helping prevent recurrent falls. They may also recommend strength and balance exercise. Tai chi, in particular, has been shown to reduce fall risk.

Geriatricians have special expertise in preventing falls, as well as improving overall function in older adults.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.

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