What Was the First Life on Earth?

19/28/18Name Student number

What Was the First Life on Earth?

The earliest evidence for life on Earth arises among the oldest rocks still preserved on the planet.

By Stephanie Pappas, Live Science Contributor

Earth is about 4.5 billion years old, but the oldest rocks still in existence date back to just 4 billion years ago. Not long after that rock record begins, tantalizing evidence of life emerges: A set of filament-like fossils from Australia, reported in the journal Astrobiology in 2013, may be the remains of a microbial mat that might have been extracting energy from sunlight some 3.5 billion years ago. Another contender for world's oldest life is a set of rocks in Greenland that may hold the fossils of 3.7-billion-year-old colonies of cyanobacteria, which form layered structures called stromatolites.

Stromatolites, like those found in the World Heritage Area of Shark Bay, Western Australia, may contain cyanobacteria, which were most likely Earth's first photosynthetic organisms. Credit: Rob Bayer/Shutterstock

Some scientists have claimed to see evidence of life in 3.8-billion-year-old rocks from Akilia Island, Greenland. The researchers first reported in 1996 in the journal Nature that isotopes (forms of an element with different numbers of neutrons) in those rocks might indicate ancient metabolic activity by some mystery microbe. Those findings have been hotly debated ever since — as, in fact, have all claims of early life.

Still, the fact that suggestive evidence of life arises right as the rock record begins raises a question, said University of California, Los Angeles, geochemist Elizabeth Bell in a SETI Talk in February 2016: Is the timing a coincidence, or were there earlier forms of life whose remnants disappeared with the planet's most ancient rocks?

The period that occurred before the rock record begins is known as the Hadean. It was an extreme time, when asteroids and meteorites pummeled the planet. Bell and her colleagues said they might have evidence that life arose during this very unpleasant time. In 2015, the research team reported discovering graphite, a form of carbon, in 4.1-billion-year-old crystals of zircon.

The ratio of isotopes in the graphite suggested a biological origin, Bell and her colleagues wrote in the journal Proceedings of the National Academy of Sciences.

These cone-shaped structures discovered in 3.7-billion-year-old rocks in Greenland, about the size of a quarter, may be fossilized colonies of microbes and the earliest fossils of life on Earth, researchers say. Credit: Allen Nutman/Nature

"There is some skepticism, which is warranted," Bell told Live Science. Meteorites or chemical processes might have caused the odd carbon ratios, she said, so the isotopes alone aren't proof of life. Since the publication of the 2015 paper, Bell said, the researchers have found several more of the rare-carbon inclusions, which the scientists hope to analyze soon.

From what is known of this period, there would have been liquid water on the planet, Bell told Live Science in an interview. There might have been granite, continental-like crust, though that's controversial, she said. Any life that could have existed would have been a prokaryote (a single-celled organism without membrane-bound nuclei or cell organelles), Bell added. If there was continental crust on Earth at the time, she said, prokaryotes might have had mineral sources of nutrients like phosphorus.

A different approach to the hunt for Earth's early life suggests that oceanic hydrothermal vents may have hosted the first living things. In a paper published in July 2016 in the journal Nature Microbiology, researchers analyzed prokaryotes to find the proteins and genes common to all of these organisms, presumably the final remnants of the Last Universal Common Ancestor (LUCA) — the first shared relative from which all life today descends.

The research team found 355 proteins shared by all archaeal and bacterial lineages. Based on those proteins, the researchers reconstructed a view of LUCA's genome, hinting that it lived in an anaerobic (oxygen-free), hydrothermal environment. If that's the case, Earth's first life (or at least the first life that left descendants) would have resembled the microbes that cluster around deep-sea vents today, the researchers said.

Putting cancer patients in hibernation could help tackle tumours

Cancer could be tackled more effectively by putting patients into a torpor state similar to that of a hibernating bear.

Tumour growth would slow right down or cease while healthy cells in the body become more resistant to radiation, says physicist Marco Durante, from the Trento Institute in Italy. The radical idea follows years of research on hibernating animals, and anecdotal reports of people who have been plunged into deep freeze and survived.

During hibernation, a form of cold temperature deep sleep, body functions such as heart and respiration rate, metabolism and oxygen uptake all slow down. At the molecular level, too, gene activity and protein synthesis are reduced to a crawling pace.

All these effects could have big implications for cancer treatment, said Durante at the American Association for the Advancement of Science (AAAS) annual meeting in Boston on February 19th.

“If you can do it, you can take (advanced) cancers that are fourth stage,” he said.

“Around 50 per cent of cancer patients have advanced cancer, so it is a large number. We all have known someone affected this way. And there is nothing that we can do with them. They have multiple metastasis (spreading tumours) in the body.

“You cannot treat all the metastasis – you cannot use surgery to everywhere to remove the cancer or do radiation in all the affected parts of the body or you will kill the patients trying to destroy the cancer,” he said. “But if you could put the patient into synthetic torpor you could stop the cancer growing. It gives you more time.”

Time to cool down

Hibernation would also the body’s ability to withstand radiation, he said. You wake up the patients and they are cured – that is our ambition.”

Currently it is not technically possible to hibernate a human in a safe and controlled way, but Durante believes that 10 years is a realistic timescale.

Synthetic torpor has been induced in rats, which unlike mice do not hibernate naturally, by manipulating a specific part of the brain, he said.

He added: “Now it is understood how it works, I’m confident we will be able to develop drugs that can induce this torpor. Then we would lower body temperature to 13C-15C.

“We are aiming for at least one week. It gives us time to deliver all the treatments that are needed to make the person cancer-free.”

Deep freeze

A normal body temperature is 37C. There are reported cases of people experiencing much lower temperatures for significant periods of time without coming to harm.

Swedish radiologist Anna Bagenholm fell into a hole in ice where she remained for more than an hour while her body temperature fell to 13.7C, the lowest ever recorded in a living human.

Despite a slight amount of nerve injury she made a complete recovery and returned to work. Another case involved Erika Nordby, a 13-month-old Canadian baby who toddled outside her house wearing only a nappy in sub-zero conditions. When she was found the temperature outside was minus 24C and she was considered clinically dead. She had no recordable heart beat.

After being placed under a warming blanket she returned to normal showing no signs of serious damage. Her doctor suggested that she may have been in a hibernation-like state.

Peter Johnson, chief clinician at Cancer Research UK, said: “The effects of a technique like induced hibernation on cancers are hard to predict: they might help or hinder the treatments we use. We will need to see some careful experiments in laboratory models before we can say whether this would be safe or effective for people”.

An alternative to opioids? Compound from marine snail is potent pain reliever

A tiny snail may offer an alternative to opioids for pain relief.

Scientists at the University of Utah have found a compound that blocks pain by targeting a pathway not associated with opioids. Research in rodents indicates that the benefits continue long after the compound have cleared the body. The findings were reported online in the February 20 issue of the Proceedings of the National Academy of Sciences.

The opioid crisis has reached epidemic proportions. Opioids is highly addictive and according to the Centers for Disease Control and Prevention, 91 Americans die every day from an opioid overdose. The medical community is in need of alternative therapies that do not rely on the opioid pathways to relieve pain.

"Nature has evolved molecules that are extremely sophisticated and can have unexpected applications," begins BaldomeraOlivera, Ph.D., professor in biology at the University of Utah. "We were interested in using venoms to understand different pathways in the nervous system."

Conusregius, a small marine cone snail common to the Caribbean Sea, packs a venomous punch, capable of paralyzing and killing its prey.

In this study, the researchers found that a compound isolated from snail's venom, RgIA, acts on a pain pathway distinct from that targeted by opioid drugs. Using rodent models, the scientists showed that α9α10 nicotinic acetylcholine receptors (nAChR) functions as a pain pathway receptor and that RgIA4 is an effective compound to block this receptor. The pathway adds to a small number of nonopioid-based pathways that could be further developed to treat chronic pain.

Interestingly, the duration of the pain relief is long, greatly outlasting the presence of the compound in the animal's system.

The compound works its way through the body in 4 hours, but the scientists found the beneficial effects lingered. "We found that the compound was still working 72 hours after the injection, still preventing pain," said J. Michael McIntosh, M.D., professor of psychiatry at the University of Utah Health Sciences. The duration of the outcome may suggest that the snail compound has a restorative effect on some components of the nervous system.

"What is particularly exciting about these results is the aspect of prevention," said McIntosh. "Once chronic pain has developed, it is difficult to treat. This compound offers a potential new pathway to prevent pain from developing in the first place and offer a new therapy to patients who have run out of options."

The researchers will continue to the next step of pre-clinical testing to investigate the safety and effectiveness of a new drug therapy.

Testing a new nonopioid compound

Previous research had shown that RgIA was effective in rodents, but the scientists wanted to ensure they had a compound that would work in people. To do this, they used synthetic chemistry to engineer 20 analogs of the compound. In essence, the scientists started with a key (RgIA) that fits into a lock (the pain pathway receptor α9α10nAChR). Using the key as a template, they developed new keys (analogs) with slightly different configurations.

The scientists found one key that best fit the lock: the analog RgIA4 tightly bound to the human receptor.

To test whether the compound relieved pain, the scientists administered it to rodents that were exposed to a chemotherapy drug that causes extreme cold sensitivity, as well as hypersensitivity to touch. "Interactions that are not normally painful, like sheets rubbing against the body or pants against the leg, becomes painful," said McIntosh.

While the untreated rodents experienced pain after exposure to the chemotherapy drug, rodents given the compound did not experience pain. Nor did rodents that were genetically altered rodents to lack the pain pathway receptor. This work demonstrates that α9α10nAChRacts as a pain pathway receptor, and that RgIA4 prevents the receptor from being activated.

Most pain medications available today work through a limited number of pathways and are not sufficient to alleviate chronic pain. "RgIA4 works by an entirely new pathway, which opens the door for new opportunities to treat pain," said McIntosh. "We feel that drugs that work by this pathway may reduce burden of opioid use."

McIntosh and Olivera collaborated with colleagues from University of Utah, University of Florence, Italy, A.T. Still University, University of Mississippi Medical Center, Kineta, Inc., Seattle, and the Veterans Affairs Medical Center, Salt Lake City.

The research was funded by National Institutes of Health, Department of Defense, and Kineta, Inc.

Origin of spooky meteor noises reappraised by Sandia researchers

When a meteor is about to conk your neighborhood and gives fair warning by emitting sizzling, rustling and hissing sounds as it descends, you might think that the universe is being sporting.

ALBUQUERQUE, N.M. - But these auditory warnings, which do occur, seem contrary to the laws of physics if they are caused by the friction of the fast-moving meteor or asteroid plunging into Earth's atmosphere. Because sound travels far slower than light, the sounds should arrive several minutes after the meteor hits, rather than accompany or even precede it.

So maybe atmospheric shock waves from the meteors are not the cause of the spooky noises.

Another theory is that the sounds are created by radio frequency emissions. That seems unlikely without designated receivers.

But what if the sounds are caused by the brilliant, pulsating light emitted by the asteroid as it burns up in Earth's atmosphere?

In an article published Feb. 1 in the journal Scientific Reports, the late Sandia National Laboratories researcher Richard Spalding reasoned that such intense light could suddenly heat the surface of objects many miles away, which in turn heats the surrounding air. This could create sounds near the observer. Colleagues John Tencer, William Sweatt, Ben Conley, Roy Hogan, Mark Boslough and Gigi Gonzales, along with PavelSpurny from the Astronomical Institute of the Czech Republic, experimentally demonstrated and analyzed that effect.

They found that objects with low conductivity, such as leaves, grass, dark paint and even hair, could rapidly warm and transmit heat into nearby air and generate pressure waves by subtle oscillations that create a variety of sounds. The process is called photoacoustic coupling.

Sounds concurrent with a meteor's arrival "must be associated with some form of electromagnetic energy generated by the meteor, propagated to the vicinity of the observer and transduced into acoustic waves," according to the article. "A succession of light-pulse-produced pressure waves can then manifest as sound to a nearby observer."

The experimenters exposed several materials, including dark cloths and a wig, to intense pulsing light akin to that produced by a fireball. The process produced faint sounds similar to rustling leaves or faint whispers. Computer models bear out the results.

A less extreme version of the photoacoustic effect had been observed in 1880 by Alexander Graham Bell when, testing the possibilities of light for long-distance phone transmissions, he intermittently interrupted sunlight shining on a variety of materials and noted the sounds produced.

Sandia National Laboratories is a multimission laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Department of Energy's National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies and economic competitiveness.

Young mother says son ‘spotted cancer’ while being breastfed

A young mother has told how her baby son saved her life after he repeatedly rejected her right breast during breastfeeding - persuading her to go to the doctor for a check-up.

Telegraph Reporters

Sarah Boyle, 26, a call centre worker, explained how Teddy, now one, would 'scream' and 'become distressed' when she tried to breastfeed him from her right breast.

Worried, she went to her GP in November 2016 and was referred to hospital where she underwent a scan and a biopsy.Two weeks later she was diagnosed with grade 2 triple negative breast cancer.

The new mum, who lives with her husband Steven Boyle, 28, a recruitment consultant from Staffordshire, is now receiving chemotherapy and is planning a double mastectomy with immediate reconstruction.

She said: "Teddy is my hero - if it hadn't been for him I would never have suspected I had cancer. My consultant told me that breastfeeding helps a mother and baby bond. "In my case it did more than that - it saved my life."Teddy could obviously smell and taste that the milk from my right breast tasted different from the milk from my left breast - and so he rejected it.