Scientists discovered a surprising gut-heart connection that may help prevent sleep apnea from causing serious cardiovascular damage. Sleep apnea affects millions of people worldwide and is known to raise the risk of serious cardiovascular problems. Now, researchers have identified a potential new treatment target that could help reduce some of the condition’s harmful effects. Findings [...]

Single cells used past nutrient shocks to change how they grew.

Tea choice significantly changes kombucha’s chemistry, flavor, and antioxidant potential, with green and oolong teas showing the strongest biological activity. Kombucha has surged in popularity worldwide in recent years, but researchers are looking beyond its flavor to better understand its chemistry and possible health-related properties. A team from the Wrocław University of Environmental and Life [...]

Scientists have uncovered evidence that tiny microbes living inside fish may be helping shape the chemistry of the world’s oceans. The new study, led by former graduate student Anthony Bonacolta at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, suggests that bacteria in fish intestines may work together with their hosts [...]

Brown rot is a common fungal disease in the Southeastern United States that affects stone fruits like peaches, cherries, and plums. Monilinia fructicola is a tan, fuzzy fungus that grows on tree flowers, twigs, and fruit, and is the most common cause of brown rot. Once brown rot infects a tree, the damage is irreversible, causing significant crop losses in commercial orchards. Farmers try to control the spread of M. fructicola by applying chemical sprays, called fungicides, to fruit trees in the spring.

In M. fructicola, a biosynthesis gene named MfCYP51 encodes a major protein critical to the fungi’s survival. Certain fungicides, called demethylation inhibitor (DMI) fungicides, stop M. fructicola from growing by targeting this protein. Over the last 20 years, DMI fungicides have become less effective against brown rot as M. fructicola becomes more resistant. 

Living microorganisms and their metabolites can control fungal diseases as an alternative to chemical fungicides, known as biofungicides. Many bacteria produce compounds like hydrogen cyanide and pyrrolnitrin that damage fungal cells. However, scientists have not found a biofungicide suitable for commercial production.​ A group of researchers at Clemson University in the USA and Huazhong Agricultural University in China set out to test whether the soil bacteria Pseudomonas chlororaphis and Bacillus subtilis could be effective biofungicides against brown rot. 

The researchers performed an incubation experiment to analyze how the fungal cells make their critical protein from the MfCYP51 gene, a process called gene expression, under different fungicide treatments. They used 3 M. fructicola strains sensitive to traditional DMI fungicides and 3 resistant strains. They tested these with 5 different fungicide treatments: a DMI fungicide, a mixture of P. chlororaphis metabolites, a mixture of living B. subtilis cells, a DMI fungicide + P. chlororaphis metabolites, and a DMI fungicide +  B. subtilis cells. They also set up a control treatment with sterile water instead of fungicide.  

After 6 hours, the researchers extracted the molecule that measures gene expression, called RNA, from the fungi. They found that both the P. chlororaphis treatment and the DMI fungicide + P. chlororaphis treatment substantially reduced MfCYP51 expression in both the sensitive and resistant isolates compared to the controls. In contrast, the DMI fungicide, B. subtilis, and DMI fungicide + B. subtilis treatments increased MfCYP51 expression in the resistant isolates. The researchers concluded that P. chlororaphis has a unique ability to reduce gene expression, unlike other biofungicides.

​To further investigate how the biofungicide treatments work, the team tested whether P. chlororaphis and B. subtilis produced the anti-fungal metabolite pyrrolnitrin. They added 1 milliliter of each treatment to a machine that separates and identifies liquid compounds using high pressure, called a high-performance liquid chromatograph. They found that the P. chlororaphis treatment contained pyrrolnitrin, so they hypothesized that it was responsible for reducing gene expression.

Additionally, the researchers tested their 5 treatments on brown rot in fruit. For each treatment, they took 10 Gala apples, washed and sterilized their surfaces, and sprayed them with the fungicides. After 24 hours, they poked holes in the apples with toothpicks and added 20 microliters of liquid containing M. fructicola cells to the poked holes. They placed the apples in a humid chamber for 5 days and measured the number and size of brown rot spots that developed on their surfaces. 

Despite decreasing MfCYP51 expression, ​the researchers found that P. chlororaphis treatment alone didn’t reduce brown rot disease compared to the control, but the DMI fungicide and B. subtilis treatments did. The mixed treatments of DMI fungicide + P. chlororaphis and DMI fungicide + B. subtilis both reduced brown rot disease compared to the control, but only the DMI fungicide + P. chlororaphis treatment prevented it. 

​The researchers concluded that although biofungicides may not be fully effective on their own, commercializing them could allow farmers to use less DMI fungicide. They explained that scaling back the use of DMI fungicides would slow M. fructicola resistance. Finally, they proposed that future researchers test biofungicide mixtures containing pyrrolnitrin in the field to observe real-world effects on stone fruit trees.

The post Using bacteria to fight fungal brown rot appeared first on Sciworthy.

Scientists discovered that fog droplets can host living bacteria that grow and help remove harmful pollutants from the atmosphere, revealing fog as a surprisingly active microbial environment. Every breath you take may contain microscopic hitchhikers floating through the atmosphere. Scientists have known for years that bacteria drift through clouds and air currents, but new research [...]

Greenhouse gases trap heat within the atmosphere. One such gas that exists beneath the ocean floor is methane. Ice-like substances on the seafloor that contain methane, known as methane hydrates, can break apart or melt, releasing methane gas into the ocean, risking further global warming. Melting permafrost, active tectonics, daily tidal patterns, and changing sea levels can similarly trigger methane’s escape from sediments. However, scientists don’t understand how these triggers will respond to future climate change.

A team of researchers hypothesized that future global warming could actually accelerate methane’s escape into the ocean. To investigate this hypothesis, they focused on an ancient global warming event approximately 56 million years ago, called the Paleocene-Eocene Thermal Maximum or PETM. Arctic Ocean temperatures at times exceeded 20°C (68°F) during this event. These elevated temperatures serve as an analog for today’s rapidly warming conditions. 

Once methane enters seawater, its fate is largely determined by 2 sets of biological processes. Today, 90% of methane released into the ocean from the seafloor is consumed by tiny organisms called microbes via a process known as anaerobic methane oxidation. During this process, microbes consume methane alongside sulfate, producing a solid iron-sulfur mineral, pyrite. Anaerobic methane oxidation prevents methane from escaping into the atmosphere by trapping it in minerals. In this case, the ocean becomes a reservoir, or sink, for methane. 

Despite this, too much methane could overwhelm the sulfate-dependent cycle. If that occurs, a different set of microbes consumes methane alongside oxygen in a process known as aerobic methane oxidation. Aerobic methane oxidation produces carbon dioxide, a potent heat-trapping greenhouse gas that escapes from the ocean. Aerobic oxidation accounts for 10% of methane consumption in oceans today, though this could have been different in the past. 

To determine how much anaerobic versus aerobic methane oxidation occurred during the PETM, the team extracted data from sediments retrieved from the Arctic Ocean floor. As sediment piles up on the seafloor, it compacts. Scientists can drill deep into the seafloor to extract a cylindrical sample, or core, of this compacted sediment. 

The age of sediments in a core increases with depth. Therefore, younger sediments exist at the top of the core, and older sediments exist at the bottom. For this project, the team used a previously extracted core from the Arctic Ocean that contained sediments dating back 100 million years. They found 56-million-year-old sediments from the PETM at a depth of 386 meters, or 1,266 feet, in this core. 

The researchers explained that microbes leave behind unique carbon-based molecules called organic biomarkers when they decompose. These organic biomarkers accumulate in seafloor sediments. The 2 different types of methane-consuming microbes leave behind 2 different biomarkers, one for anaerobic methane oxidation and one for aerobic methane oxidation. This team measured the amount of each biomarker in the sediment core to determine which microbes were dominant during the PETM. 

The biomarker left behind from microbes performing aerobic methane oxidation is called hop(17)21-ene. The researchers noticed that the amount of hop(17)21-ene increased by a factor of 4 during the PETM. At the same time, the biomarker left behind from microbes performing anaerobic methane oxidation, called glycerol dialkyl tetraether, decreased to half. They interpreted these trends to reflect the rise of aerobic methane cycling and the shutdown of anaerobic methane cycling, respectively. They attributed this transition to the release of enough methane to overwhelm the sulfate-dependent methane cycle under warming conditions.

To estimate the amount of carbon dioxide produced by aerobic methane oxidation during the PETM, the researchers located another biomarker in the sediment core, called phytane. Phytane is produced by organisms that consume carbon dioxide during photosynthesis, and its structure preserves clues to the amount of carbon dioxide available at the time. The researchers found that during and well after the PETM, the concentration of carbon dioxide in the Arctic Ocean was 4 times greater than modern levels. They concluded that the Arctic Ocean became a prolonged source of carbon dioxide to the atmosphere, even after the PETM.

The team suggested that the uptick in aerobic methane oxidation during the PETM serves as an analog for the modern Arctic Ocean, which continues to warm rapidly in the face of modern climate change. Their results highlight how the transformation of methane into carbon dioxide poses a threat. More carbon dioxide in the atmosphere warms the air, which heats the oceans, causing more methane to escape from the seafloor and eventually be converted into additional carbon dioxide. When triggered, this feedback would continue to amplify and could become difficult to recover from.  

The post Does the Arctic Ocean regulate or amplify global warming? appeared first on Sciworthy.

Rod-shaped fragments of RNA called “obelisks” were discovered in gut and mouth bacteria for the first time

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