How did MRSA become a superbug?

Superbugs are bacteria that have acquired resistance to several types of antibiotic drugs either through genetic mutation or through build up of resistance over time chiefly due to the misuse or overuse of antibiotics. This means that certain antibiotics which have saved millions of lives earlier will no longer be effective against such bacteria. Scientists call them drug-resistant bacteria or antibiotic-resistant bacteria and they are posing a significant health threat globally today.

Scientists discovered one such superbug called the MRSA (or methicillin-resistant staphylococcus aureus) in 2011. It was thought to have emerged in cows given the large amounts of antibiotics used among cattle. However, a team of international researchers have found that drug-resistant bacteria MRSA evolved naturally about 200 years ago as a result of a battle between a parasitic fungus species and a bacteria species that share space on the skin of wild hedgehogs While the use of antibiotics often drives the evolution of superbugs, this study shows the origins of some antibiotic-resistant bacteria in Nature.

How did the superbug evolve on hedgehog?

Researchers found two kinds of organisms living on the skin of European hedgehogs. They were the superbug Staphylococcus aureus and the parasitic fungus Erinaceus europaeus. The fungus secretes the antibiotic methicillin (a form of penicillin), which inhibits the growth of Staphylococcus aureus to increase its chance of survival. The bacteria, in turn, evolved antibiotic resistance to outsmart their fungal rivals and thrive on their hedgehog hosts. Researchers believe that this particular strain of bacteria that colonised the hedgehogs, known as mecC-MRSA, might have found its way their livestock and eventually to humans.

What's more?

The team sequenced the genomes of the fungus on the hedgehogs and found the genes responsible for producing the antibiotics and then they sequenced the bacteria. Through genetic coding, researchers were able to establish a timeline of the evolution of the hedgehog-borne mecC-MRS. They found that the bacteria had resistance to methicillin as early as the 1800s, long before the clinical use of penicillin began in the 1940s.

(Alexander Fleming discovered penicillin in 1928, a fact you might have read about in your classes. If you remember the story of the penicillin discovery, you would know that Fleming noticed that the staphylococci on the petri dish he had left behind in his lab prior to a vacation had been destroyed by the mold or fungus that had developed on the gel in the dish.)

What led to the development of antibiotic resistance?

There are multiple factors that led to the increase in antibiotic resistance among bacteria.

  • Bacteria are living organisms and they evolve, adapting to new environments and new challenges, just like any other organism.
  • The trait of antibiotic resistance develops over time.
  • Bacteria share genes with other bacteria, and thus pass on the resistance.
  • Bacteria strong enough to survive a drug will have a chance to grow and multiply.
  • While antibiotic resistance occurs naturally, misuse of antibiotics in humans and animals is accelerating the process.
  • Unnecessary prescription by physicians or self-medication by patients: If an antibiotic is taken against a viral infection, the drug does not target the disease-causing virus but instead kills the good bacteria that aid in digestion and in fighting infection.
  • Improper disposal of medical waste leads to contamination of water and soil where the bacteria acquire resistance.

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Deadly tornadoes slam through six states

More powerful, destructive, and deadlier storms will be the "new normal" as the effects of climate change take root, the top U.S. emergency management official said after massive tornadoes ravaged six states.

Meteorologists and other scientists have long warned of the growing intensity of weather events like storms, fires and flooding.

But the crisis hit the U.S. in a terrifying way when more than two dozen twisters raked across large swaths of the American heartland, leaving more than 90 people dead, dozens missing and communities in ruin.

"This is going to be our new normal," Deanne Criswell, head of the Federal Emergency Management Agency, told CNN'S "State of the Union." "The effects that we're seeing from climate change are the crisis of our generation," she added. Criswell warned of the challenge that the United States faces in addressing such severe weather events.

In another programme, she told ABC's "This Week," "We're seeing more intense storms, severe weather, whether it's hurricanes, tornadoes, wildfires. The focus I'm going to have is, how do we start to reduce the impacts of these events." The tornado that reduced several towns to rubble was a gargantuan twister. It rumbled along the ground for over 320 km, one of the longest, if not the longest on record.

What causes a tornado?

Tornadoes are whirling, vertical air columns that form from thunderstorms and stretch to the ground. They travel with ferocious speed and lay waste to everything in their path. Thunderstorms occur when denser, drier cold air is pushed over warmer, humid air, conditions scientists call atmospheric instability. As that happens, an updraft is created when the warm air rises. When winds vary in speed or direction at different altitudes- a condition known as wind shear-the updraft will start to spin. These changes in winds produce the spin necessary for a tornado. For especially strong tornadoes, changes are needed in both the wind's speed and direction.

Role of climate change

Scientists say figuring out how climate change is affecting the frequency of tornadoes is complicated. But they do say the atmospheric conditions that give rise to such outbreaks are intensifying in the winter as the planet warms. One paper published recently by scientific association AGU says its analysis "suggests increasing global temperature will affect the occurrence of conditions favourable to severe weather."

Rising global temperatures are driving significant changes for seasons that we traditionally think of as rarely producing severe weather. Stronger increases in warm humid air in fall, winter, and early spring mean there will be more days with favourable severe thunderstorm environments - and when these storms occur, they have the potential for greater intensity. Projections suggest that stronger, tornado-producing storms may be more likely as global temperatures rise, though strengthened less than we might expect from the increase in available energy. Studies have shown that the rate of increase in severe storm environments will be greater in the Northern Hemisphere, and that it increases more at higher latitudes.

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Do black kites spreading fire?

Black kites, whistling kites and brown falcons are known as "firehawk raptors". They help spread wildfires in places like Australia by picking up and dropping lit branches or embers onto fresh patches of dry grass so as to scare out small animals. It makes it easier for them to swoop down to catch the fleeing prey.

Ongoing bird research will help answer questions, of course. “There’s loads to find out,” Bonta says, citing recent findings. “We just learned in 2016 that birds’ neurons are packed differently. They’re way smarter than we thought. We’re just beginning to understand avian memory. Crows’ problem-solving ability is amazing. There are a lot of tool-using behaviors.”

Part of the reason Westerners may have trouble accepting the concept of firehawks, Bonta suggests, is our lack of connection to our environment: “Westerners have done little but isolate ourselves from nature,” he says. Yet those who make a point of connecting with our earth in some form—he uses turkey hunters as an example—“have enormous knowledges because they interact with a species. When you get into conservation [that knowledge] is even more important.” Aborginal people “don’t see themselves as superior to or separated from animals. They are walking storehouses of knowledge.”

Credit : Penn State Altoona 

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Great Pacific Garbage Patch Becomes an Ocean Habitat for Coastal Species

The Great Pacific Garbage Patch is the name given to the floating waste, mostly comprising plastic, in the open ocean between California and Hawaii. Spread across 1.6 million sq km, the patch is estimated to contain 79,000 tonnes of plastic waste! It is the largest of the world's five trash-filled gyres, which form when plastic and other forms of waste are taken out to sea by surface currents and are then trapped and gathered together into great masses by rotating currents.

Bad? Indeed! But what's worse is that a host of coastal organisms have hitch-hiked on the drifting garbage all the way to the Great Pacific Garbage Patch and have made a comfortable home there. They are not only sustaining themselves in the open ocean, but are also thriving. Scientists have known that coastal species could catch rides out to sea on logs and seaweed in the past. But they haven't formed a community of their own because most times these logs and other natural carriers disintegrate along with their riders. But plastic waste is creating opportunities for coastal species to greatly expand beyond what was previously thought possible. Thus, the impact of plastic waste on marine organisms is not just ingestion and entanglement.

New concern

The arrival of these new coastal organisms (which can be invasive) has the potential to deeply affect an ecosystem that is already delicate and lacking in resources, warn scientists.

Scientists have documented more than 40 coastal species clinging to plastic trash, in a study published in the journal Nature Communications. These include mussels, barnacles and shrimp-like amphipods. The scientists found that a mix of coastal and open ocean species have joined together on the plastic-creating something entirely new. They call these new communities neopelagic 'neo' meaning new and pelagic referring to the open ocean.

The team is still unsure as to how the neopelagic colonies are finding food - it is possible the plastic itself is acting as a reef and attracting food sources to it. Nor are they sure whether such colonies exist in other trash-filled gyres. However, as the production of global plastic waste continues to increase, scientists think such colonies of coastal organisms in the open ocean will continue to grow.

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What is a fungal network? And how does it work as a carbon sink?

Scientists from the Society for the Protection of Underground Networks (SPUN) have launched plans to map the world's huge underground webs of fungi, which store billions of tonnes of carbon dioxide during their lifetime. The SPUN would collect 10,000 samples from around the world to identify sites with the potential to store more CO2 and withstand changes brought about by global warming. The project will also identify at-risk areas, where these networks are under threat from fertilizer use, urbanisation, deforestation, and pollution. Understanding the fungal network will help scientists focus on "underground conservation", which has been long overlooked.

Symbiotic relationship

A majority of land plants live in symbiotic relationship with soil fungi. The fungi cannot photosynthesise, as they have no access to light or chlorophyll, whereas the trees photosynthesise. Trees use the sun's energy to refashion carbon dioxide and water into sugar. Fungi get sugar and carbon from trees, and in return release nutrients such as phosphorous and nitrogen, as well as water (collected from their environment) to the trees. Some fungi are known to supply 80% of phosphorus to their host plants.

"Wood wide web"

The fungi are made up of a mass of thin threads, known as mycelium, through which they absorb nutrients from their environment. The roots of trees and mycelium join together to form the mycorrhizal networks. As fungi colonise many plants at the same time, the mycorrhizal networks connect individual plants and trees, forming a larger network. This network ferries nutrients and chemical signals (communication) between trees. They even connect trees that are miles away. German forester Peter Wohlleben dubbed this network the wood wide web".

Carbon sink

According to the SPUN, underground fungal networks sequester carbon in three ways. First, fungi use carbon to build rapidly expanding networks in the soil.

Second, sequestered carbon is used to create fungal exudates. Exudates are organic compounds that help form stronger soil aggregates, which act as a stable carbon reservoir. Third, sequestered carbon is stored in fungal necromass. Necromass are underground networks that are no longer active, but whose complex architecture is structurally woven into the soil matrix. It is responsible for up to half of the total soil organic matter and helps stabilise soils. Ecosystems with plants that feed carbon to underground networks store an estimated eight times more carbon compared to ecosystems with non-mycorrhizal vegetation, say scientists.

Other functions of the fungal network

Food web: Fungal networks lie at the base of the food webs because they feed the plants with necessary nutrients.

Sharing of resources: Trees and plants share nutrients with one another through the fungal network. There is also increasing evidence that some combinations of fungi can enhance soil fertility and plant productivity more than others.

A parent tree uses the fungal network to feed the seedlings that have sprouted under its shade. Researchers have found how old trees are able to survive with resources from younger ones.

Helps in tree 'communication': The tree-to-tree communication happens for various purposes and in many forms. It may not be a typical 'Hello'. But it is definitely a network of sharing and caring, and that ensures the survival of the community. Through the fungal network, trees send distress chemical signals about drought, disease or an insect attack. Other trees pick up these signals and increase their own resistance to the threat.

Boosts immunity of plants: A fungal network also boosts the host plants' immune system because when a fungus colonises the roots of a plant, it triggers the production defence-related chemicals in plants.

Threats to fungal network

Agriculture: Adding of fertilizer interrupts the dynamics of exchange between plants and fungi, while ploughing damages the physical integrity of fungal networks.

Habitat loss: Habitat loss led by logging and urbanisation also cause damage to the underground fungal networks.

Warming and climate change: Extreme temperatures, drought, and floods threaten the ability of global fungal networks to move nutrients and store carbon. And wildfires not only destroy trees, but also the fungal network underground.

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