Swimming with Viruses

8641509698_ac47920d89_bYou can find viruses everywhere: in the soil, in the clouds and in animals. According to scientists from the University of Oldenburg in Germany, there are also a ridiculous number of viruses buried at sea, in the sediments of the oceans.

These sedimentary viruses don’t lie dormant on the seabed, but actively replicate down in the fathoms, even in the gyres of the ocean where most forms of life can’t be sustained since organic carbon is a scarce commodity. By infecting and killing prokaryotic cells (bacteria, archaea) in ocean sediments, viruses act as efficient organic carbon recycling machines.

Scientists found that in every sediment tested, from active tidal flats, open oceans and nutrient-poor gyres, viruses vastly outnumbered prokaryotic host cells. Active viruses didn’t just exist in the oceanic topsoil, but rather permeated through deep layers laid down millions of years ago. Bacteriophages (viruses that infect bacteria) could be found in layers of sediment 320m deep, and in ancient layers from ~14 million years ago.

These exciting findings mean that viruses are actively replicating in buried ocean sediments all the time, and are thus making a huge contribution to the maintenance and carbon cycling of oceanic microbial communities.

Engelhardt T, Kallmeyer J, Cypionka H, & Engelen B (2014). High virus-to-cell ratios indicate ongoing production of viruses in deep subsurface sediments. The ISME journal PMID: 24430483

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Posted in Bacteria, Ecology, Marine, Microorganisms, Science, Viruses | Tagged , , , , , , , , , , , , , | Leave a comment

More evidence that red wine and aspirin protect against cancer

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Cancer is a disease of genes. DNA mutations mess with the genetic content of a cell, enabling it to escape the normal controls that restrict their growth.

Now, a team of scientists led by Delphine Lissa and Guido Kroemer at the French Institute of Health and Medical Research in Paris have begun exploring ways to slow or stop the formation of cells containing multiple copies of chromosomes, which they think are an essential intermediate in cancer formation.

Normal healthy cells are diploid, which means they have two copies of each chromosome, one from each parent. But during cancer formation, early malignant cells are often tetraploid, with four sets of chromosomes—the extras are either mistaken copies created in-house or genomes picked up from other cells.

Most cells deal with tetraploidy by committing suicide before they become malignant. These genomically deviant cells can also get removed by the immune system as part of its routine cancer surveillance program. But sometimes, these cells are not dealt with, allowing them to continue accumulating chromosomes and acquiring new genetic mutations, transforming them into dangerous cancer cells.

Enjoying that drink

In their study, published in the Proceedings of the National Academy of Science, Lissa and colleagues looked for drugs that could kill tetraploid cells, but leave healthy diploid cells relatively intact. After screening a panel of 480 bioactive chemicals from a database at Harvard Medical School, they came up with two hits: aspirin and resveratrol.

Aspirin is a common presence in the medicine cabinet, and has an excellent record against disease. Almost all of us have enjoyed its headache-relieving properties, and many old people are advised to take small doses of aspirin to protect their hearts. There is also evidence that aspirin can prevent colon cancer.

Those of us who enjoy red wine are ingesting resveratrol on a regular basis. It is also found in red grapes, peanut butter, dark chocolate, and blueberries. While it is still not certain exactly what protective effects resveratrol has against disease, there are suggestions that it can prolong lifespan, protect the heart, and prevent certain forms of cancer.

When researchers looked closely at the fates of both dangerous tetraploid or normal diploid cells treated in a dish with their two drug hits, they observed that unhealthy cells were controlled at least partially through the activation of signals that coaxed them into committing suicide.

Lissa also looked at the use of statins, which work through some biological pathways that may overlap with those tweaked by aspirin and resveratrol (they are commonly prescribed to control high cholesterol levels and minimise the risk of heart disease and stroke). In mixed populations of diploid and tetraploid cells, statins selectively induced more tetraploid cells to die. Several agents, then, could suppress the growth of genetically unstable cells capable of causing cancer.

Stopping cancer in its tracks

After establishing that their drugs had useful effects against fully-formed tetraploid cells, Lissa looked into whether the team could prevent such dangerous tetraploid cells from forming in the first place. Seems it can be done—resveratrol, aspirin, and their biochemical derivatives also reduced the formation of tetraploid cells.

When tested in mice prone to intestinal cancer, either oral resveratrol or aspirin lowered cancer rates. By probing gut cells with fluorescent tags, they saw that fewer dangerous tetraploid cells formed in treated animals. So both drugs could normalise the gut environment to minimise the likelihood of cancer.

2009-04-03T14-53-19 IMG_9796Out of the other 478 screened drug candidates, most had no differential impact on dangerous versus normal cells. Several other agents, including the chemotherapeutic agent cisplatin, the food supplement quercetin, and the herbicide paraquat, preferentially killed normal diploid cells but allowed the dangerous tetraploid cells to continue growing.

This study shouldn’t be viewed as justifying opening a bottle of red wine. Lissa didn’t investigate the effects of these drugs on normal cells that are meant to contain more than two pairs of chromosomes—certain cells in the liver, heart, immune system, and reproductive organs all normally have extra chromosomes. Also, aspirin may have limited use as a long-term anti-cancer agent due to its serious side effects (causing bleeds in the stomach). Finally, it’s not clear whether tetraploid cells are a necessary intermediary to cancer.

Still, beyond cancer, Lissa’s method shows that approved drugs could be screened for treating other diseases, reducing the cost of finding new treatments.

Originally published on The Conversation UK.

Lissaa, D., Senovillaa, L., Rello-Varona, S., Vitalee, I., Michauda, M., Pietrocola, F., Boilèvea, A., Obrist, F., Bordenave, C, Garcia, P., Michels, J., Jemaà, M., Kepp, O., Castedo, M., & Kroemer, G. (2014). Resveratrol and aspirin eliminate tetraploid cells for
anticancer chemoprevention PNAS DOI: 10.1073/pnas.1318440111

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Bright Night Lights: Tracking Light Pollution from Space

6483519343_0199a1c7f1_bThe creep and sprawl of artificial urban lighting is probably the most pervasive technological innovation of the 20th century. Keeping track of how artificial light is changing Europe’s nightscape is important, since more light is typically associated with greater economic development and urban expansion, but moderating light consumption helps to stabilise the ecosystem and energy security.

Scientists have recently used satellite night images going back as far as 1992 (publicly available from the Defense Meterological Satellite Program databank) to analyse how artificial light coverage across the European landscape has changed through the years.

light in europeOverall, light brightness across Europe increased over the years (shown above), with Liechtenstein showing the strongest surge. Conversely, certain countries showed substantial drops in brightness, most notably Slovakia. Small spots puckering the UK, Belgium, Denmark, Finland, Germany, Norway and Sweden also dimmed over time, and often corresponded with a loss of industrial manufacturing, the closure of military sites, the modernisation of lighting infrastructures or deliberate money-saving measures. In other areas, darkness coincided with a loss of economic stability, for example when Ukraine and Moldova became independent from the Soviet Union.

This extremely cool research shows that it’s possible to track changes in light brightness across the European night sky, giving us an excellent tool to help develop interventions that minimise the effects of light pollution and re-establish the ability to enjoy the sensational stars hanging over our heads.

Bennie J, Davies TW, Duffy JP, Inger R, & Gaston KJ (2014). Contrasting trends in light pollution across Europe based on satellite observed night time lights. Scientific reports, 4 PMID: 24445659

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Where in the body do our emotions lie?

lego emotions cc danielito311

Emotions are strange things, bursting over us as we react to life’s joys and challenges. While they might be thought of as ethereal entities with no fixed form or function, emotions actually produce very tangible physical reactions throughout the body.

These emotionally-driven physical reactions are important for surviving in the real world. For example, fear generates a helpful physical response that prepares your body to fight or flee. But we don’t really know if an emotion can fuel a reaction in a certain body part, or if regional body sensors can dictate our conscious emotional experiences.

A team of Finnish researchers were interested in finding out more about this, so they showed 701 volunteers an outline of the human body, and asked them to point out spots on that body where they felt a change in activity (either growing stronger or weaker) after they experienced an emotion generated by a certain word, story, film or facial expression.

They exposed the volunteers to six “basic” emotions (anger, fear, disgust, happiness, sadness and surprise) and seven “complex” emotions (anxiety, love, depression, contempt, pride, shame and envy), and tried their best to weed out the inherent bias of using emotive words that are culturally and lingustically associated with body parts, like “heartache”.

feeling emotions

After mapping out the results as emotional activity charts across the human body, they found that positive emotions like happiness, love and pride all looked very similar, with a suffusion of high activity (shown in yellow, above) around the heart, head, and, ahem, nether regions (for love). These associations were supported by some lovely quantitative cluster analysis.

Several of the negative emotions assembled into similar patterns: fear and anger increased activity in the chest, anxiety and shame increased activity in the torso, sadness and depression severely decreased activity in the arms and legs (shown in blue, above), while disgust, contempt and envy increased activity in the head and hands.

So, clearly, emotions can pin themselves quite reliably and reproducibly to certain areas of the human physical form, in a way that transcends cultural heritage (both Western European and Eastern Asian volunteers reacted in the same way). Such bodily associations and sensations likely have a key part in the emotional experience, and may have a core role in helping us to understand emotions in others.

Nummenmaa L, Glerean E, Hari R, & Hietanen JK (2013). Bodily maps of emotions. Proceedings of the National Academy of Sciences of the United States of America PMID: 24379370

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Antibiotics release death sugars that help bad bugs to grow

4619706028_7c9e124627_bIn the 1940’s, antibiotics were hailed as wonder drugs. “Syphilis is now curable!”, ran the posters. Yet in modern times, several dark sides of these drugs have come to light.

The widespread overuse of antibiotic therapy has driven the emergence of superstrong bacteria, like MRSA, that resist the activity of conventional antibiotics.

Antibiotic therapy is also troubled by the problematic core concept that it lacks specificity, and wipes out good and bad bugs alike. This is particularly worrying as we continue to discover just how much the trillions of good bugs that live in our gut contribute to our health and wellbeing, absorbing vitamins from our food, breaking down tough fibrous vegetables, working to prevent allergies and keeping bad bugs in check.

When good bugs are killed off by antibiotics, the gut ecosystem becomes remarkably disturbed. Large pools of sugary nutrients that the good bugs normally eat suddenly become available, forming an all-you-can-eat buffet for surviving bacteria. Unfortunately, the post-antibiotic apocalypse scavengers are often bad bugs, like Salmonella enterica and Clostridium difficile, which can cause unpleasant disease.

New research from Stanford University School of Medicine shows that both Salmonella enterica and Clostridium difficile use the same strategies to access these free pools of death sugars. Using genetic profiling, they found that in the wake of antibiotic therapy, the bad bugs increased their capacity to snack on fucose and/or sialic acid. Consequently, they were able to overgrow in the intestine to cause pooping nastiness.

While the community of good bugs began to be re-established around three days after antibiotic therapy, and the balance of good and bad bugs stabilised, eating probiotics packed with good bugs that are particularly adept at eating fucose and sialic acid during antibiotic therapy may prevent such pathogenic disturbances happening at all.

Ng KM, Ferreyra JA, Higginbottom SK, Lynch JB, Kashyap PC, Gopinath S, Naidu N, Choudhury B, Weimer BC, Monack DM, & Sonnenburg JL (2013). Microbiota-liberated host sugars facilitate post-antibiotic expansion of enteric pathogens. Nature, 502 (7469), 96-9 PMID: 23995682

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