Tag Archives: contaminants

Fiber mat.

Scientists manage to keep proteins ‘alive’ outside cells

Researchers from the US have developed a method that allows them to keep proteins ‘alive’ outside of cells. The discovery paves the way for advanced materials that have the same functionality as living organisms — for example, mats that scrub air clean of chemical pollution.

Fiber mat.

Image credits Christopher DelRe, Charley Huang/UC Berkeley

Proteins don’t much like living outside of cells. We know this because researchers have been trying to get proteins stable in other environments for years now, but with very limited success. Efforts to combine these proteins with synthetic materials and still keep them functional for any length of time met a similar fate.

A new paper, however, details a method that can be used to keep these proteins active in synthetic environments, finally allowing researchers to cash in on their activity on demand.

Problems

Proteins are the heavy lifters of biochemistry. Quite literally — its constricting proteins that make your muscles, and by extension, you, move. But take them outside of the cozy place we call ‘the body’ and they fall apart quite easily. Even if they somehow survive, it doesn’t mean they will actually be doing anything. One of their most significant limitations is that proteins need to be folded just right for them to work; often, this means other proteins have to come in and do the folding.

In order to work around that problem, the team analyzed protein sequences, folding patterns, and various surfaces to see if they could develop a polymer that would cater to the proteins’ needs — to keep their structures unaltered, and thus maintain function.

“Proteins have very well-defined statistical pattern, so if you can mimic that pattern, then you can marry the synthetic and natural systems, which allows us to make these materials,” says first author Brian Panganiban.

The next step was to create random heteropolymers, or RHPs. Thpotentey’re basically the same things as a polymer (plastics), but instead of using a single type of ‘brick’ (molecules known as monomers), they use two or more different, but similar monomers. The RHPs the team developed used four types or monomers, with each being tailored to chemically interact with spots of interest along the proteins. The monomers were connected in such a way as to mimic the structure of natural proteins to help these interactions flow smoothly.

Researchers at Northwestern University simulated the molecule and its interaction with proteins of interest and determined that the material led to correct protein folding and would maintain protein stability outside living cells.

Filter me this

So far so good, but the team wanted to go beyond simulations and test their results in real life. They decided to use the RHPs and proteins to construct bioremediation filters. The protein they chose for the job was organophosphorus hydrolase (OPH), which degrades toxic organic-phosphate compounds, such as those found in insecticides or chemical warfare agents.

They spun the RHP/OPH into fiber mats and submersed them in insecticide. The mats degraded an amount of insecticide weighing approximately one-tenth of the mat’s weight in just a few minutes. The team says the mats are easily scalable and can be customized with different proteins meaning their technology could be used for a wide range of applications. In fact, at least part of the funding for this research came from the US Department of Defense — the mats can be used to soak up chemical weapons in war zones, to scrub contaminated areas, even as on-demand, handheld filters.

“We think we’ve cracked the code for interfacing natural and synthetic systems,” says co-author Ting Xu, a professor at the University of California, Berkeley.

Despite the interest shown by military planners, the mats show great potential in the bioremediation of areas polluted with chemical contamination events. Because RHPs can be customized with a wide range of proteins — which means a wide range of substances they can interact with, and several ways to do so — Xu’s team believes their work could form the basis for portable chemistry labs of the future, a fast response team for potential environmental contamination events.

The paper “Random heteropolymers preserve protein function in foreign environments” has been published in the journal Science.

Chimps.

Chimps get grossed out too, pointing to the origins of disgust in humans

Despite sometimes engaging in some pretty gross behavior, chimps don’t like yicky things either, a new paper reveals. The findings offer a glimpse into the roots of our own sense of disgust.

Chimps.

Image via Pixabay.

Chimps aren’t the best-mannered animals out there. In the wild, they have been observed to pick out seeds from feces and eat them. In captivity, some have been spotted engaging in coprophagy — the deliberate ingestion of feces. All of which we’d definitely characterize as being downright disgusting behavior.

Banan-eeewww!

But that doesn’t mean they don’t feel disgusted at all. The behaviors we’ve mentioned above usually involve each chimps’ own feces, or at most that of their immediate family members. If presented with bodily fluids or feces from other chimps, however, they will exhibit behaviors very suggestive of disgust. In theory, animals evolved this aversion to protect themselves from parasites and pathogens. In humans, bodily products are a universal elicitor of disgust, and the paper found evidence that exposure to biological contaminants — via vision, smell, or touch — also elicit similar reactions in chimpanzees by influencing feeding choices.

“If chimpanzees and other primates can discern contamination risk via different cues, individuals with higher sensitivities to feces and other bodily fluids may be less infected, which could have important health benefits,” explains Cecile Sarabian, the lead author of the study.

The team worked with 20 chimpanzees (Pan troglodytes troglodytes) at the Centre International de Recherches Médicales de Franceville (CIRMF) in southern Gabon. Throughout a series of experiments, the team was able to show that chimps will generally delay eating potentially contaminated food items.

First, the primates were presented with a choice of three bananas — one on a piece of brown foam (control sample), one placed on a replica pink feces, and one placed on a brown replica. The team reports that the chimps would first select the bananas atop the control foam and the pink feces replica significantly more often than the ones on the brown feces replica. This shows “a preference for food that is not associated with contamination risk” but not an “avoidance of such risk altogether,” as generally, they would still eat all three bananas.

The animals also showed a “weak tendency” of moving away from the smell of potential biological contaminants (conspecific feces, blood, and semen) compared to a control sample of water. Food trials revealed that the smell of blood or semen again had a limited effect on the chimps’ appetite compared to a control odor (they ate the bananas given to them 93%, respectively 92% of times, compared to 93% with control odor). Finally, they also tended to move away from and/or consume food items less often when associated with odors of these potential contaminants, the authors write. These tendencies were overall weak, the scientists add, suggesting that “the threat levels perceived [by the chimps] may not have been great.”

Icky fingers

For the third experiment, the team worked with 42 chimps. The primates were presented with a foraging task designed to put them into surprise tactile contact with two hidden substrates: dough, which has been used in human experiments to replicate the consistency, temperature, and moisture of a potentially contaminated substrate, or a piece of rope used as a control. Both substrates were hidden inside a box so the chimps couldn’t see them. What the chimps did see, however, was that the team placed pieces of banana in each box.

The chimps that received a box with rope substrate ate the banana pieces roughly 91% of the time. In contrast, their dough-boxed counterparts only ate the food 54% of the time. It’s the single most powerful disgust behavior elicited by the chimps in this study. The results are very similar to the behaviors shown by humans when blindly touching soft and moist substrates, which are generally more contaminant-rich than hard and dry substances.

“While anyone watching the reactions of these chimpanzees in the tactile experiments can empathize with them, it’s premature to say that they feel the same as we might in that situation” cautions Andrew MacIntosh, senior author on the study.

“What’s great about these experiments, though, is that the observed responses are functionally similar to what ours would be, providing evidence that the mechanism underlying their behavior could be similar to ours.”

The results help pave the way to understanding the disgust mechanism in humans and the protective function it serves.

“Moreover, such results may have implications for animal welfare and management. We can better inform staff and keepers about the adaptive value of such sensitivity and its flexibility, as well as identify which individuals may be more at risk of infection and therefore require more attention,” concludes Cecile Sarabian.

The team is now working on “expanding our ‘disgusting’ work” to other primate and non-primate species to get a more bird’s eye view of how the emotion forms and functions.

The paper “Avoidance of biological contaminants through sight, smell and touch in chimpanzees” has been published in the journal Royal Science Open Society.

waterways chemicals

U.S. waterways pack a slew of chemical compounds, from pesticides to pharmaceuticals

The US Geological Survey (USGS) found a worrying amount of chemicals with a biological impact in water samples taken from major U.S. rivers and streams. They monitored only a couple hundred chemicals known to be sourced from human activity but even so they found 56 percent of them inside the fresh water. This suggests that the real number of man-made chemicals present in freshwater streams could be in the order of thousands, some of which can provoke a worrying biological response.

waterways chemicals

Credit: Pixabay.

The team sampled water from 35 waterways, three of which located far from human settlements and activity to serve as a control. Water close to both rural and urban environments was sampled, then screened for a select group of 719 chemical compounds. Of these, no fewer than 406 were detected which tells us man-made chemicals are diffusing in great numbers into the broader environment.

The most common chemicals were 8 pesticides and 2 pharmaceuticals, namely caffeine and metformin. The latter is a drug commonly used to treat type-2 diabetes.

After this first test established which chemicals were present, the researchers performed a new experiment that was meant to assess their effect on living organisms. Specifically, the researchers were interested what impact the chemicals found in the water samples had on estrogen, androgen, and glucocorticoid receptors. Unsurprisingly, all three receptors were affected in some way. At this point, it’s important to note that the biological effects of the contaminants were tested not an individual basis, but as a whole like a soup. But even considering this fact, the researchers still don’t know why the androgen (male sex hormones) and glucocorticoid receptors, which bind to anti-inflammatory compounds like steroids, reacted so strongly.

One possible explanation might be that only a fraction of the 85,000 known chemicals that we manufacture were tested. This seems more likely, although it’s possible that the combination of chemicals is collectively causing an integrated response that we’re not aware of yet. As for the source of these chemicals, it’s anyone’s guess. It’s not that these chemicals are dumped into the waterways by some malevolent person or company. Everything we ingest and consequently excrete gets mixed up and ends up in water supplies via sewers despite it may pass through a waste treatment plant. Case in point, the study found the closer to a wastewater treatment facility the sampled water was, the higher was the chemical concentration.

For now, the long-term environmental and health effects are not known but the biological tests clearly suggest that the contaminants have some sort of effect. All living beings need water, and as such, all the slew of chemicals we consume and dump in the water ends up in plants, fish, animals that eat all these plant and fish, and eventually back inside us.

The study which appeared in the journal Environmental Science and Technology doesn’t draw any conclusions beyond the reported facts. The findings, however, merit starting a discussion about it. Governmental agencies might want to work together on this one to figure out what’s the best course of action to minimize man-made chemicals leaching into the waterways. There are already some solutions discussed by the scientific community, none of which is cheap or easy. Waste could be treated closer to the source as opposed to collecting it and drugs could be designed to degrade faster.