bacteria

Protecting Fresh Produce | Earth Wise

May 26, 2020 By EarthWise Leave a Comment

Fresh fruits and vegetables can sometimes become contaminated by microorganisms during their long journey from fields to restaurants and grocery stores. Contaminated produce can spoil other produce, which increases the number of fruits and vegetables in the supply chain that can cause illnesses.

In order to prevent this cross-contamination between produce, researchers from Texas A&M University have designed a coating that can be applied to food-contact surfaces, like buckets, rollers, and conveyor belts. The newly-created dual-function coating is both water-repellent and germicidal. In other words, it can both repel and kill. Without water, the researchers say bacteria can’t stick or multiply on surfaces, drastically reducing contamination.

To make this dual-function coating, the researchers chemically-attached a thin layer of silica to an aluminum sheet. They then added a mixture of silica and lysozyme, a naturally-occurring germicidal protein found in egg whites and tears. Together, the silica-aluminum and the silica-lysozyme formed microscopic bumps and crevices. According to the research team, this rough texture, albeit microscopic, is the key to the coating’s superhydrophobic properties.

The researchers tested the coating’s effectiveness at curbing the growth of two strains of disease-causing bacteria: Salmonella and Listeria. Upon review, the number of bacteria found on the dual-coating surfaces was 99.99% less than what was found on the uncoated surfaces.

Despite the success in preventing bacterial spread, the research team said more research needs to be done to see how well the coating works for mitigating viral cross-contamination. Since the coating would need to be reapplied after a certain amount of use, the researchers also plan to develop more permanent, dual-function coatings.

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New dual-action coating keeps bacteria from cross-contaminating fresh produce

Photo, posted April 14, 2012, courtesy of U.S. Department of Agriculture via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Methane-Eating Bacteria And Greenhouse Gas Emissions | Earth Wise

May 20, 2020 By EarthWise Leave a Comment

One of the great concerns about the warming Arctic temperatures is that thawing permafrost will release alarming amounts of methane into the atmosphere. Organic material in the permafrost begins to decompose when temperatures rise, and methane is released in the process.

Methane is a far more potent greenhouse gas than carbon dioxide. Methane’s lifetime in the atmosphere is much shorter than carbon dioxide, but it is more efficient at trapping radiation. Pound for pound, the comparative impact of methane is more than 25 times greater than carbon dioxide.

A new study, published by scientists at Purdue University, has discovered a type of methane-oxidizing bacteria living in upland Arctic soils that could potentially be reducing the amount of methane emitted by decomposing permafrost.

The findings of the research indicate that the net greenhouse gas emissions from the Arctic may be much smaller than previously modeled because of the increased productivity of a type of bacteria known as high affinity methanotrophs, or HAMs. This group of bacteria uses atmospheric methane as an energy source. The emissions from wetlands will potentially be very large, but the contribution from the uplands will be mitigated by the bacteria.

Organic-rich soils, including permafrost, comprise only 13% of the Arctic land area and are the major source of methane emissions. The other 87% of the region is dominated by mineral-rich soils that support HAMs. Because of this, overall methane emissions continue to be less than climate models have predicted.

While this is good news, the researchers warn that Arctic emissions overall will continue to increase as shown in other studies.

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Methane-Eating Bacteria Could Help Decrease Greenhouse Gas Emissions From Thawing Arctic Tundra

Photo, posted July 12, 2016, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Hidden Source Of Arctic Carbon | Earth Wise

April 24, 2020 By EarthWise Leave a Comment

Researchers from the University of Texas at Austin, the U.S. Fish and Wildlife Service, and Florida State University have published a paper presenting evidence of significant and previously undetected concentrations and fluxes of dissolved organic matter entering Arctic coastal waters. The source of the organic matter is groundwater flow atop the frozen permafrost. The groundwater moves from land to sea unseen, but the new research reveals that it carries significant concentrations of carbon and other nutrients to Arctic coastal food webs.

Globally, groundwater is important for delivering carbon and other nutrients to oceans, but in the Arctic, where much water is trapped in the permafrost, its role was thought to be minimal. But the new research reveals that groundwater may be contributing an amount of dissolved organic matter to the Alaskan Beaufort Sea that is comparable to what comes from neighboring rivers during the summer.

The researchers found that shallow groundwater flows beneath the surface and picks up new, young organic carbon and nitrogen, but it also mixes with layers of deeper soils and thawing permafrost, picking up and transporting century-to-millennia old organic carbon and nitrogen. This material is unique because it is directly transported to the ocean without seeing or being photodegraded by sunlight and may be valuable as a food source to bacteria and higher organisms that live in Arctic coastal waters.

The study concluded that the supply of leachable organic carbon from groundwater amounts to as much as 70% of the dissolved organic matter that enters the Beaufort Sea from rivers during the summer. The role that groundwater inputs play in Arctic coastal ecosystems will be an area of active research for years to come.

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Hidden Source of Carbon Found at the Arctic Coast

Photo, posted June 14, 2015, courtesy of Eugen Marculesco via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A New Kind Of Antibiotic | Earth Wise

March 10, 2020 By EarthWise Leave a Comment

Antimicrobial resistance is a serious and growing problem for public health. Over time, more and more types of bacteria have become resistant to known antibiotics making it very difficult to treat various kinds of infections.

A new group of antibiotics with a unique approach to attacking bacteria has been discovered at McMaster University in Canada, representing a promising new clinical approach in the fight against antimicrobial resistance.

The newly found corbomycin and the lesser-known complestatin have a never-before-seen way to kill bacteria, namely, breaking the function of the bacterial cell wall. Bacteria have a wall around the outside of their cells that gives them shape and is a source of strength. Antibiotics like penicillin kill bacteria by preventing building of the wall, but the new antibiotics work by doing the opposite – they prevent the wall from being broken down. Breaking down the cell wall is critical for cells to divide. In order for bacteria to grow and spread, they need to expand and divide. By completely blocking the breakdown of the wall, it is as if the bacterium is trapped in a prison and can’t expand or grow.

The researchers demonstrated in mice that these new antibiotics can block infections caused by the drug resistant Staphylococcus aureus which is a group of bacteria that can cause many serious infections.

The researchers believe this new approach can be applied to other antibiotics and lead to the discovery of new ones with different mechanisms of action. This study found one completely new antibiotic, but since then, they have found a few others in the same family that have this same new mechanism.

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Antibiotics discovered that kill bacteria in a new way

Photo, posted March 15, 2012, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mexico’s Wonder Plant

September 13, 2019 By EarthWise Leave a Comment

In 1979, an American naturalist named Thomas Hallberg visiting a small town in Oaxaca, Mexico was amazed to find a type of local maize – or corn – that grew nearly 20 feet high in poor-quality soil even though the local farmers did not use any fertilizer.

The unique corn plant had aerial roots that grew a mucous-like gel just before harvest season. It seemed totally implausible, but the plant seemed to be fixing its own nitrogen: extracting it from the air and somehow making it useful to the plant.

In 1992, Hallberg returned with a group of Mexican scientists and collected samples to study in his lab. His research showed that the maize indeed received nitrogen from the air through its aerial roots. It took over 20 years to figure out what was going on in the plants. It turns out that bacteria that thrive in the low-oxygen environment of the maize’s mucus pulls nitrogen from the air and feeds it to the plant.

Scientists will probably spend years figuring out if a commercial application of this indigenous maize is viable. It isn’t guaranteed that the self-fertilizing trait of the plant can be bred into a commercial crop. But if it can, the payoff would be huge. Farmers spend more than $3 billion a year on corn fertilizer in the US alone.

A vexing problem is who should reap the financial benefits of the maize. The isolated village where the plant is grown has already signed an agreement to share in any such benefits. But there are other Oaxacan villages that also grow the plant.

Mexico’s wonder plant is likely to be caught up in the growing issue of biopiracy, which is the exploitation of indigenous knowledge and biological resources without permission.

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Indigenous Maize: Who Owns the Rights to Mexico’s ‘Wonder’ Plant?

Photo credit: ALLEN VAN DEYNZE/UC DAVIS

Earth Wise is a production of WAMC Northeast Public Radio.

Reducing Methane From Animals

September 3, 2019 By EarthWise Leave a Comment

Methane emissions from ruminant livestock are currently estimated to be more than 100 million tons each year and, after rice agriculture, represent the biggest human-initiated methane source. Given that fact, there is widespread encouragement for people to reduce their consumption of meat in order to reduce the amount of the potent greenhouse gas going into the atmosphere.

But an additional strategy to lower global methane emissions is to actually reduce the amount of methane produced by each animal. To that end, researchers at the University of Otago in New Zealand have now identified new processes that control methane production in the stomachs of sheep and similar animals like cattle and deer.

They determined the specific microbes and enzymes that control the supply of hydrogen, which is the main energy source for methane producing microbes, known as methanogens. Their work is focused on the development of small molecule inhibitors and vaccines to specifically target the production of methane by methanogens. By reducing the supply of hydrogen to methanogens, it is possible to reduce animal methane emissions.

The research involved studying two types of sheep – those producing large amounts of methane and those producing less. They found that the most active hydrogen-consuming microbes differed between the sheep. Specifically, in the low methane emitting sheep, hydrogen consuming bacteria dominated over methanogens.

Ultimately, a strategy might emerge to introduce feed supplements that encourage non-methane producers to out-compete methanogens. Controlling the supply of hydrogen to the methanogens will lead to reduced methane emissions.

Having low-emission cattle would definitely help reduce the impact of agriculture on the climate.

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Scientists discover processes to lower methane emissions from animals

Photo, posted April 7, 2017, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Controlling Malaria Without Chemicals

August 28, 2019 By EarthWise Leave a Comment

Nearly half of the world’s population lives in areas vulnerable to malaria. The disease kills roughly 450,000 people each year, most of them children and pregnant women. Malaria is spread by Anopheles mosquitoes and, over time, the mosquitoes have been developing resistance to the chemical insecticides that are used to control them. In addition, there is great concern about the toxic side effects of the chemicals used on the mosquitoes.

About 30 years ago, scientists identified a type of bacteria that kills Anopheles, but the mechanism was not understood. As a result, the bacteria could not be replicated or used as an alternative to chemical insecticides.

But now, an international research team, headed by researchers at UC Riverside, has identified the neurotoxin produced by the bacteria and has determined how it kills Anopheles. The work is described in a paper published in Nature Communications.

It took the team 10 years to achieve a breakthrough in understanding the bacteria. Modern gene sequencing techniques were the key.

While many neurotoxins target vertebrates and are highly toxic to humans, the neurotoxin that kills Anopheles mosquitoes does not affect humans, vertebrates, fish, or even other insects. Known as PMP1, the substance is not even toxic to mice when given by direct injection.

The team has applied for a patent on this discovery and hopes to find partners to help them develop the bacteria-based insecticide.

There is a high likelihood that PMP1 actually evolved to kill the Anopheles mosquito. This finding opens the door to new avenues of research into other environmentally friendly insecticides that would be targeted at other disease-spreading pests.

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Controlling deadly malaria without chemicals

Photo, posted June 9, 2018, courtesy of Mario Yardanov via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Drugs In The Water

April 15, 2019 By EarthWise Leave a Comment

According to a new study published in the journal Environmental Research Letters, concentrations of pharmaceuticals in rivers and lakes have dramatically increased across the globe over the past 20 years.

Traces of medicines get passed into waterways through the excretion of active drugs in human waste, the disposal of unused medicines down drains, and runoff from livestock farms.

The study looked in detail at two specific drugs: carbamazepine, an anti-epileptic drug, and ciprofloxacin, an antibiotic. The study found that the risk of ecological damage from the residue from these two drugs was 10 to 20 times higher in 2015 than in 1995.

Chronic exposure to carbamazepine, for example, has been shown to alter feeding behavior and reduce egg viability in zebrafish, as well as reduce reproductive success in crustaceans. Antibiotics can alter major nutrient cycles and decrease the effectiveness of bacteria-based wastewater treatment systems.

The study, led by researchers from the Netherlands, created a new model estimating concentrations of the two drugs over a 20-year period in 449 aquatic systems around the globe. The model predicts a relatively high environmental risk in densely populated and dry areas such as the Middle East.

When the researchers compared the model’s results to samples from four river systems in various locations, they found that the actual drug concentrations were even higher than model results, in some cases by a factor of 10 to 100.

The new model should act as a guide for a more thorough investigation into pharmaceutical residues in waterways, which pose significant environmental risks all over the world.

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Concentrations of Pharmaceuticals in Freshwater Increasingly Globally

Photo, posted March 22, 2012, courtesy of Rajeev Rajagopalan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Protection From Toxic Algae

March 28, 2019 By EarthWise Leave a Comment

Toxic algal blooms have been a growing problem in recent years associated with warming waters and nutrient-rich agricultural runoff in lakes, rivers, and oceans. In 2014, an algal bloom in Lake Erie left half a million residents of Toledo, Ohio without safe drinking water for three days.

The most common toxic substance released by algal blooms in the lake is called microcystin, which is closely linked to liver cancer and other diseases. Toxicologists measure microcystin and other contaminants using the metric of parts per billion. The EPA recommends that young children not drink water containing more than 0.3 parts per billion and adults no more than 1.6 parts per billion of microcystin.

Scientists at the University of Toledo have been working on developing a biofilter that uses naturally occurring Lake Erie bacteria to remove microcystin released by algal blooms and thereby reduce or eliminate the use of chlorine and other chemicals.

They have successfully isolated a number of types of bacteria that degrade microcystin toxin at a daily rate of up to 19 parts per billion. To their knowledge, such bacteria have not been previously used to fight algal blooms in other parts of the world. Based on the recorded toxin levels in Lake Erie in recent years, the bacteria would be able to effectively remove microcystin from water supplies. None of the 13 bacterial isolates they found have any association with human disease so their use in future water-purifying biofilters should not pose a public health concern.

The researchers are now developing and testing biofilters, which are water filters containing the specialized bacteria that will degrade the toxins from lake water as it flows through the filter.

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Scientists advance new technology to protect drinking water from Lake Erie algal toxins

Photo, posted April 30, 2014, courtesy of NOAA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Disease On Coral Reefs

February 19, 2019 By EarthWise Leave a Comment

The warming oceans have led to bleaching events in coral reefs around the world, but bleaching is not the only problem corals face. Disease outbreaks are also becoming more frequent, severe, and widespread.

Many factors are contributing to the problem, including pollution and nitrogen runoff from fertilizers and coastal sewer and septic systems. However, the key culprit is likely the steadily increasing ocean temperatures, which are the cause of coral bleaching. Elevated water temperatures can cause coral polyps to expel the algae that sustains them and gives them color.

According to scientists, bleaching makes corals more susceptible to illness. In the Caribbean, a coral disease hotspot, about 80% of coral cover has disappeared, largely from outbreaks of “white band disease”, so called because of a white band of dead tissue that forms in affected corals. Two crucial reef-building species, elkhorn and staghorn coral, are now nearing extinction in the regions. The reef extending along the Florida coastline is the third largest reef ecosystem in the world and nearly 35% of it has been lost to disease.

Estimates are that disease outbreaks have wiped out at least 6% of the corals on the Great Barrier Reef in Australia. In that region, diseases are more prevalent in areas where corals were damaged by fishing and other human activity because wounded coral provides an entry point for pathogens and bacteria.

In the face of climate change and mounting disease outbreaks, scientists are scrambling for solutions to stave off catastrophe. Assisting the migration of hardier coral species and breeding so-called “super corals” are among the strategies being pursued. It is unknown whether these and other forms of intervention can be used on a wide enough scale to really make a difference.

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As Disease Ravages Coral Reefs, Scientists Scramble for Solutions

Photo, posted November 29, 2012, courtesy of Robert Linsdell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Electricity From A Bionic Mushroom

December 28, 2018 By EarthWise Leave a Comment

In an engineering feat straight out of a weird science-fiction story, researchers at Stevens Institute of Technology in New Jersey have taken an ordinary white button mushroom and used 3D printing technology to coat it with graphene microribbons and cyanobacteria to produce a device that generates electricity.

Better Sell-By Dates For Milk

October 2, 2018 By EarthWise Leave a Comment

The sell-by and best-by dates on milk cartons are ones we tend to pay close attention to. Many of us automatically discard milk if it is past one of those dates. However, those dates are not really scientifically established but rather are guesses based on experience.

Bacteria-Powered Solar Cell

August 29, 2018 By EarthWise 1 Comment

Commercially-available solar panels are composed of solar cells that are most often made from various forms of silicon. Some panels use thin-film cells made from other semiconductor materials. Solar cells utilize a property of semiconductors that allows them to convert light energy into electrical energy.

Fighting Methane With Bacteria

June 14, 2018 By EarthWise Leave a Comment

Bacteria may have an important role to play in the effort to reduce greenhouse gas emissions. A group of researchers at the University of Alberta are genetically engineering non-hazardous bacteria that consume methane and turn it into fuel.

An Accidental Plastic Eater

May 29, 2018 By EarthWise Leave a Comment

A couple of years ago, scientists in Japan discovered bacteria at a recycling plant that were breaking down a type of plastic called polyethylene terephthalate, or PET. With the world facing a growing plastic pollution problem, British and American researchers began to study the enzyme that the bacteria were using to try to understand how it works.

A Weird Answer To A Serious Problem

April 25, 2018 By EarthWise Leave a Comment

Resistance to antibiotics is a rising problem that costs an estimated 700,000 lives each year. Some experts predict that if the problem can’t be solved, that number could grow to 10 million deaths annually by 2050. As a result, researchers around the world are investigating multiple ways to help fight antibiotic resistance.

Carbon And The Dark Ocean

January 4, 2018 By EarthWise Leave a Comment

Sunlight entering the water can travel as much as 3,000 feet into the ocean depths under the right conditions, but ordinarily there is no significant light that penetrates beyond about 650 feet down. That upper 650 feet is called the euphotic or “sunlight” zone and is home to most familiar marine life. The “dark ocean”, everything below that depth, makes up 90% of the ocean and remarkably little is known about it.

Carbon And Heating Soil

November 22, 2017 By EarthWise 1 Comment

Plants are a critical part of the Earth’s carbon cycle. They take in carbon dioxide during photosynthesis. Eventually, dead leaves, branches and other materials fall to the ground where bacteria and fungi decompose the materials and release the CO2 back into the atmosphere. This carbon-soil feedback loop is a complicated one that is critical to the overall carbon balance because soils actually contain two to three times more carbon than the atmosphere.

Super Blooms

September 27, 2017 By EarthWise Leave a Comment

This past August one of the driest regions on Earth transformed from a barren desert to a sea of colorful flowers. Heavy rains in Chile’s Atacama Desert caused the phenomenon, locally known as the desierto florido or flowering desert. These things typically only happen every five to seven years, but the previous super bloom actually took place in 2015.

[Read more…] about Super Blooms

New Rules For Ocean Conservation

September 21, 2017 By EarthWise Leave a Comment

In a recent report to a United Nations ocean conference, scientists are warning that new rules are desperately needed to protect marine life in the open seas. That’s because more than 60% of the ocean has no conservation rules since it’s located outside national jurisdictions. The open ocean is at risk from climate change, over-fishing, deep sea mining, farm pollution, and plastics pollution.