They found that bacteria belonging to the Methylococcaceae family have been hitching a ride on the feathery plumes that act as the respiratory organs of Laminatubus and Bispira worms. Methylococcaceae are methanotrophs, meaning that they harvest carbon and energy from methane, a molecule composed of carbon and hydrogen.

The worms, which are a few inches long, have been found in great numbers near deep-sea methane seeps, vents in the ocean floor where hydrocarbon-rich fluids ooze out into the ocean, although it was unclear why the worms favored the vents. As it turns out, the worms slowly digest the hitchhiking bacteria and thus absorb the carbon and energy that the bacteria harvest from the methane.

That is to say, with a little help and some extra steps, the worms have become methanotrophs themselves.

“These worms have long been associated with seeps, but everyone just assumed they were filter-feeding on bacteria. Instead, we find that they are teaming up with a microbe to use chemical energy to feed in a way we hadn’t considered,” says Victoria Orphan, James Irvine Professor of Environmental Science and Geobiology and co-corresponding author of a paper on the worms that was published by Science Advances on April 3.

Orphan and her colleagues made the discovery during research cruises to study methane vents off the coast of Southern California and Costa Rica.

“We had a colleague on board who was an expert on these worms and noticed that the morphology was unusual. The respiratory plumes were much frillier than anyone had ever seen before, which was the first clue. It was enough to make us say, ‘That’s interesting. We should investigate,'” says Shana Goffredi, visitor in geobiology at Caltech and lead author of the Science Advances paper. Goffredi is an associate professor of biology at Occidental College in Los Angeles.

To probe the nature of the relationship between the worms and the bacteria, the scientists had to first use robotic submarines to take samples from deep-sea methane vents, which, in this case, lie 1,800 meters below the ocean surface.

Once the worms were brought topside, the scientists analyzed their tissues, cataloging the carbon isotopes that they had consumed. Carbon exists in two stable isotopic forms — different “flavors” of carbon, so to speak. Around 99 percent of all carbon is carbon-12, which has six neutrons and six protons in each atomic nucleus, and about 1 percent is carbon-13 (six protons and seven neutrons). Carbon-14, a radioactive isotope, exists in trace amounts.

All organisms require carbon — in some form — to survive, and they absorb it through metabolic processes. Studying the ratio of carbon-13 to carbon-12 in an organism’s tissues can give clues to where that carbon came from and the conditions under which it formed. In the case of the deep-sea worms, their tissues had an unusually low ratio of carbon-13 to carbon-12, meaning that the carbon in the worm’s body probably came from methane. Orphan and her collaborators reasoned that because the worms are incapable of processing methane directly, they must be getting their carbon from methanotrophic bacteria.

“The fact that we found this specific isotope of carbon throughout the worms’ bodies and not just in their respiratory plumes indicates that they are consuming methane carbon from these bacteria,” Orphan says. The research team followed up on this hypothesis by using molecular techniques and microscopy as well as experiments to test the ability of these worms to incorporate a modified, traceable version of methane.

Their research findings change our understanding of seep ecosystems and have implications for deep-sea stewardship, as methane seeps and hydrothermal vents are sure to experience increasing pressure because of human exploitation of energy and minerals.

Story Source:

Materials provided by California Institute of Technology. Original written by Robert Perkins. Note: Content may be edited for style and length.

Aerosols are particles small enough to travel through the air. Ordinary speech creates significant quantities of aerosols from respiratory particles, said William Ristenpart, professor of chemical engineering at UC Davis. Ristenpart is co-author on an editorial about the problem to be published in the journal Aerosol Science and Technology.

These respiratory particles are about one micron, or one micrometer, in diameter. That’s too small to see with the naked eye, but large enough to carry viruses such as influenza or SARS-CoV-2.

Some individuals superemitters

Last year, Ristenpart, graduate student Sima Asadi and colleagues published a paper showing that the louder one speaks, the more particles are emitted and that some individuals are “superemitters” who give off up to 10 times as many particles as others. The reasons for this are not yet clear. In a follow-up study published in January in PLOS One, they investigated which speech sounds are associated with the most particles.

Calculating just how easily a virus like SARS-CoV-2 spreads through droplets requires expertise from different fields. From virology, researchers need to know how many viruses are in lung fluids, how easily they form into droplets and how many viruses are needed to start an infection. Aerosol scientists can study how far droplets travel once expelled, how they are affected by air motion in a room and how fast they settle out due to gravity.

“The aerosol science community needs to step up and tackle the current challenge presented by COVID-19, and also help better prepare us for inevitable future pandemics,” Ristenpart and colleagues conclude.

Other authors on the editorial are Asadi; Professor Anthony Wexler, UC Davis Department of Mechanical and Aerospace Engineering; and Nicole Bouvier, Icahn School of Medicine at Mount Sinai.

Story Source:

Materials provided by University of California – Davis. Original written by Andy Fell. Note: Content may be edited for style and length.

In a paper published in Nature Communications, a group of cell biologists led by Meng Chen, a professor of botany and plant sciences at the University of California, Riverside, reveal the phytochrome B molecule has unexpected dynamics activated by temperature, and behaves differently depending on the temperature and type of light.

As climate change warms the world, crop growth patterns and flowering times will change. A better understanding of how phytochromes regulate the seasonal rhythms of plant growth will help scientists develop crops for optimal growth under the Earth’s new climate and might even shed light on cancer in animals.

Phytochromes switch between active and inactive forms like a binary switch controlled by light and temperature. In direct sunlight, such as in open fields, phytochromes switch “on,” absorbing far-red light. This active form inhibits stem elongation, which limits how tall plants in direct sunlight can grow.

In shade phytochromes are less active, absorbing red. This “off” form releases the inhibition of stem growth, so plants grow taller in shade to compete with other plants for more sunlight.

Within the cell, light causes “on” phytochromes to coalesce into units called photobodies inside the cell nucleus. When phytochrome B is off, it resides outside the cell nucleus. It moves inside the nucleus when “on” and changes the expression of genes and growth patterns.

Changes in light alter the size and number of all foci. Chen’s group has now shown temperature alters individual foci.

His group examined the behavior of cells exposed to different temperature and light conditions from the leaves and stems of Arabidopsis thaliana, a plant used as a standard model in botany science. The goal was to monitor how photobodies change in response to temperature.

The current understanding is that phytochromes form photobodies only in the “on” state.

Chen and co-authors Joseph Hahm, Keunhwa Kim, and Yongjian Qiu, members of Chen’s research group at UC Riverside, expected increasing the temperature would have a similar effect to shade — it would switch the phytochromes “off.” They thought the photobodies would disappear, as in shade.

The results were completely unexpected.

The team found increasing the temperature did not cause all the photobodies to disappear at once. Instead, specific photobodies disappeared in specific ranges of temperature. Increasing the temperature incrementally reduced the number of photobodies as they disappeared selectively.

“We found that a subset of thermostable photobodies can persist even in warm temperatures,” Chen said. “The rest of the foci would disappear at each stage of lower temperature. Before we thought all the foci were the same, but now we know they are all different.”

The mechanism that makes them disappear selectively must be different from the mechanism that makes them disappear in shade. This suggests individual photobodies could be sensors for specific temperature ranges.

The study also showed phytochrome B reacts to temperature from two different locations on the molecule. The first part senses temperature; the second part forms foci. Foci formed by this second location are insensitive to temperature. This shows light and temperature are sensed by the same part of the molecule but result in different behaviors.

“Photobodies are large, dynamic protein complexes. Our results suggest that each of them could have a different composition,” Chen said. “What we think is that the unique composition of individual photobodies make them react to temperature differently. Future studies on understanding the unique features of each photobody will likely uncover the underlying mechanisms of temperature sensing and the regulation of temperature-responsive gene expression in plants.”

In addition to helping develop plants that will thrive in a warming world, this work could help scientists learn more about cancer in animals. Proteins in animal cells also form foci related in some way to cancer, but their role in gene expression and regulation is unknown.

Two researchers, Haizhou Liu, an associate professor of chemical and environmental engineering at the University of California, Riverside; and Professor Vincenzo Naddeo, director of the Sanitary Environmental Engineering Division at the University of Salerno, have called for more testing to determine whether water treatment methods are effective in killing SARS-CoV-19 and coronaviruses in general.

The virus can be transported in microscopic water droplets, or aerosols, which enter the air through evaporation or spray, the researchers wrote in an editorial for Environmental Science: Water Research & Technology, a leading environmental journal of the Royal Society of Chemistry in the United Kingdom.

“The ongoing COVID-19 pandemic highlights the urgent need for a careful evaluation of the fate and control of this contagious virus in the environment,” Liu said. “Environmental engineers like us are well positioned to apply our expertise to address these needs with international collaborations to protect public health.”

During a 2003 SARS outbreak in Hong Kong, a sewage leak caused a cluster of cases through aerosolization. Though no known cases of COVID-19 have been caused by sewage leaks, the novel coronavirus is closely related to the one that causes SARS, and infection via this route could be possible.

The novel coronavirus could also colonize biofilms that line drinking water systems, making showerheads a possible source of aerosolized transmission. This transmission pathway is thought to be a major source of exposure to the bacteria that causes Legionnaire’s disease, for example.

Fortunately, most water treatment routines are thought to kill or remove coronaviruses effectively in both drinking and wastewater. Oxidation with hypochlorous acid or peracetic acid, and inactivation by ultraviolet irradiation, as well as chlorine, are thought to kill coronaviruses. In wastewater treatment plants that use membrane bioreactors, the synergistic effects of beneficial microorganisms and the physical separation of suspended solids filter out viruses concentrated in the sewage sludge.

Liu and Naddeo caution, however, that most of these methods have not been studied for effectiveness specifically on SARS-CoV-19 and other coronaviruses, and they have called for additional research.

They also suggest upgrading existing water and wastewater treatment infrastructure in outbreak hot spots, which possibly receive coronavirus from places such as hospitals, community clinics, and nursing homes. For example, energy-efficient, light-emitting, diode-based, ultraviolet point-of-use systems could disinfect water before it enters the public treatment system.

Potable water-reuse systems, which purify wastewater back into tap water, also need thorough investigation for coronavirus removal, and possibly new regulatory standards for disinfection, the researchers wrote.

The extent to which viruses can colonize biofilms is also not yet known. Biofilms are thin, slimy bacterial growths that line the pipes of many aging drinking water systems. Better monitoring of coronaviruses in biofilms might be necessary to prevent outbreaks.

The surge in household use of bactericides, virucides and disinfectants will probably cause an increase of antibiotic-resistant bacteria in the environment. Treated wastewater discharged into natural waterways demands careful monitoring through the entire water cycle. Liu and Naddeo call on chemists, environmental engineers, microbiologists, and public health specialists to develop multidisciplinary and practical solutions for safe drinking water and healthy aquatic environments.

Lastly, developing countries and some regions within highly developed nations, such as rural and impoverished communities, which lack the basic infrastructure to remove other common contaminants might not be able to remove SARS-CoV-19 either. These places might experience frequent COVID-19 outbreaks that spread easily through globalized trade and travel. Liu and Naddeo suggest governments of developed countries must support and finance water and sanitation systems wherever they are needed.

“It is now clear to all that globalization also introduces new health risks. Where water and sanitation systems are not adequate, the risk of finding novel viruses is very high,” Naddeo said. “In a responsible and ideal scenario, the governments of developed countries must support and finance water and sanitation systems in developing countries, in order to also protect the citizens of their own countries.”

In laboratory experiments, the masks significantly reduced the amounts of various airborne viruses coming from infected patients, measured using the breath-capturing “Gesundheit II machine” developed by Dr. Don Milton, a professor of applied environmental health and a senior author of the study published April 3 in the journal Nature Medicine.

Milton has already conferred with federal and White House health officials on the findings, which closely follow statements this week from the head of the Centers for Disease Control and Prevention saying the agency was reconsidering oft-stated advice that surgical masks aren’t a useful precaution outside of medical settings. (The debate takes place at a time when clinicians themselves face dangerously inadequate supplies of masks — a shortfall other UMD researchers are scrambling to help solve.)

The question of masks has roiled society as well, with some retailers refusing to let employees wear them for fear of sending negative signals to customers, and cases of slurs and even physical attacks in the United States and elsewhere against Asians or Asian Americans who were wearing masks, a measure some consider a necessity during a disease outbreak.

The study, conducted prior to the current pandemic with a student of Milton’s colleagues on the Faculty of Medicine at the University of Hong Kong, does not address the question of whether surgical masks protect wearers from infection. It does suggest that masks may limit how much the infected — who in the case of the novel coronavirus often don’t have symptoms — spread diseases including influenza, rhinoviruses and coronaviruses.

Milton, who runs the Public Health Aerobiology, Virology, and Exhaled Biomarker Laboratory in the School of Public Health, demonstrated in a 2013 study that surgical masks could help limit flu transmission. However, he cautions that the effect may not be as great outside of controlled settings.

Nevertheless, he said, the chance they could help justifies taking a new look at whether all people should be encouraged to wear them when they venture out of their houses to stores or other populated locations during the current COVID-19 lockdown.

“In normal times we’d say that if it wasn’t shown statistically significant or the effective in real-world studies, we don’t recommend it,” he said. “But in the middle of a pandemic, we’re desperate. The thinking is that even if it cuts down transmission a little bit, it’s worth trying.”

Previous studies have shown that coronavirus and other respiratory infections are mostly spread during close contact, which has been interpreted by some infectious disease specialists to mean that the disease could spread only through contact and large droplets, such as from a cough or sneeze — a message that has often been shared with the public.

“What they don’t understand is that is merely a hypothesis,” Milton said. The current study (along with earlier ones) shows, by contrast, that tiny, aerosolized droplets can indeed diffuse through the air. That means it may be possible to contract COVID-19 not only by being coughed on, but by simply inhaling the breath of someone nearby who has it, whether they have symptoms or not. Surgical masks, however, catch a lot of the aerosolized virus as it’s exhaled, he said.

The study was conducted at the University of Hong Kong as part of the dissertation research of the lead author, Dr. Nancy Leung, who, under the supervision of the co-senior authors Drs. Cowling and Milton, recruited 246 people with suspected respiratory viral infections. Milton’s Gesundheit machine compared how much virus they exhaled with and without a surgical mask.

“In 111 people infected by either coronavirus, influenza virus or rhinovirus, masks reduced detectable virus in respiratory droplets and aerosols for seasonal coronaviruses, and in respiratory droplets for influenza virus,” Leung said. “In contrast, masks did not reduce the emission of rhinoviruses.”

Although the experiment took place before the current pandemic, COVID-19 and seasonal coronaviruses are closely related and may be of similar particle size. The report’s other senior author, Professor Benjamin Cowling, division head of epidemiology and biostatistics, School of Public Health, HKUMed, and co-director of the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, said, “The ability of surgical masks to reduce seasonal coronavirus in respiratory droplets and aerosols implies that such masks can contribute to slowing the spread of (COVID-19) when worn by infected people.”

Milton pointed to other measures his research has found is even more effective than masks, such as improving ventilation in public places like grocery stores, or installing UV-C lights near the ceiling that works in conjunction with ceiling fans to pull air upwards and destroy viruses and bacteria.

“Personal protective equipment like N95 masks are not our first line of defense,” Milton said. “They are our last desperate thing that we do.”

Hong Kong University contributed to this report.