Weight Loss Microbes & Supernovae | SciByte 88

Posted on: April 2, 2013

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Weight Loss Microbes & Supernovae | SciByte 88

We take a look at stomach microbe changes, a new type of tiny supernovae, tracking a swarm of bugs, spacecraft and story updates, Curiosity news, and as always take a peek back into history and up in the sky this week.

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Show Notes:

Microbes and Weight Loss

  • Previous studies of people and rats have found that the natural mix of microbes in the intestines changes after gastric bypass, with some groups growing more prominent and others diminishing in number
  • No one knew whether the altered microbial composition was merely a side effect of the surgery, or whether shifting bacterial populations could help people lose weight.
  • The Study
  • To find out researchers fattened up mice then performed either bypass or a sham surgery on the animals
  • They performed a Roux-en-Y, the most common technique for gastric bypass, which diverts food around most of the stomach and upper small intestine
  • Because it bypasses part of the stomach and small intestine, the surgery alters the intestinal environment, changing elements such as pH and bile concentrations
  • Mice in the bypass group lost about 29 percent of their body weight within three weeks of the procedure
  • Even before the mice dropped weight, those in the bypass group already had an altered mix of intestinal bacteria
  • Compared with the sham operation group, the bypass mice had more of certain types of microbes
  • Some species of those microbes are pathogens, but others help prevent inflammation and maintain intestinal health
  • The bypass mice also had more bacteria, which can feed on mucus lining the intestines, particularly when the host is cutting calories
  • Then the researchers transplanted bacteria from the intestines of bypass mice into mice that had been raised without any bacteria
  • The formerly germ-free mice slimmed down, trimming about 5 percent of their body weight, even though they started out lean
  • The germ-free mice that received bacteria from the guts of sham surgery mice actually packed on a bit of fat
  • Of Interest
  • By colonizing mice with the altered microbial community, the mice were able to maintain a lower body fat, and lose weight, about 20% as much as they would if they underwent surgery
  • Researchers speculate that the microbes somehow trigger fat-burning changes in the host’s metabolism
  • Even with these positive results the results were somewhat biased against weight loss
  • The mice used in the study hadn\’t been given a high-fat, high-sugar diet to increase their weight beforehand
  • There is some question whether a stronger effect might have been seen if they were on a different diet
  • In many people with type 2 diabetes, the disease vanishes almost immediately after surgery, too quickly to be explained by the gradual weight loss that happens later
  • Patients also describe not being as hungry, or craving foods like salad that they hadn\’t liked much before
  • Figuring Out What is Going On
  • While the specific microbes found at higher abundance after surgery, are good targets for beginning to understand what\’s taking place, there is a major gap in knowledge is the underlying mechanism linking microbes to weight loss
  • For instance, in addition to changes in the microbes found in the gut, researchers found changes in the concentration of certain short-chain fatty acids
  • Other studies have suggested that those molecules may be critical in signaling to the host to speed up metabolism, or not to store excess calories as fat.
  • The ultimate answer as to what is going on may not be the specific types of microbes, but a by-product they excrete.
  • It may be years before this research could be replicated in humans, and that such microbial changes shouldn\’t be viewed as a way to lose weight without going to the gym
  • The Future
  • More research is needed to learn more about the mechanisms by which a microbial population is changed by gastric bypass exert its effects,
  • Then we need to learn if we can produce these effects, either the microbial changes or the associated metabolic changes, without surgery
  • Another question is whether the transplants will have the same effect in animals who weren\’t raised in a sterile environment and who already have their own gut microbiome, which would more closely mimic people undergoing gastric bypass surgery
  • This technique may one day offer hope to dangerously obese people who want to lose weight without going through the trauma of surgery.
  • Future studies will allow us to understand how host/microbial interactions in general can influence the outcome of a given diet
  • Multimedia
  • YouTube | Gastric Bypass Surgery | TangstarScience
  • Further Reading / In the News
  • Microbes May Slim Us Down After Gastric Bypass – ScienceNOW | news.ScienceMag.org
  • Gut microbes may be behind weight loss after gastric bypass | Genes & Cells | Science News
  • A new way to lose weight? Study shows that changes to gut microbiota may play role in weight loss | MedicalXPress.com

— NEWS BYTE —

New Tiny Supernova\’s

  • Supernovae
  • Until now, supernovae have come in two main versions
  • In Type II supernovae a huge star, 10 to 100 times more massive as our Sun, collapses causing a colossal stellar explosion
  • Type Ia supernovae, occurs when material from a parent star streams onto the surface of a white dwarf. Over time, so much material falls onto the white dwarf that it raises the core temperature igniting carbon and causing a runaway fusion reaction. This event completely disrupts the white dwarf and results in a colossal stellar explosion
  • Now astronomers have found a third type that is fainter and less energetic than a Type Ia, called a Type Iax supernova, essentially a mini supernova only about one-hundredth as bright as their supernova siblings
  • Type Iax Supernova
  • The data gathered suggest that, like a Type Ia supernova, a Type Iax supernova comes from a binary star system containing a white dwarf and a companion star
  • In Type Iax supernovas, the companion star has apparently already lost its outer hydrogen, leaving it dominated by helium
  • The white dwarfs then go on to accumulate helium from their companion stars.
  • What happens from there is unclear
  • One explanation involves the ignition of the outer helium layer from the companion star. The resulting shock wave slams into the white dwarf and disrupts it, causing the explosion.
  • Alternately, the white dwarf might ignite first due to the density and pressure from the overlying helium shell it has collected from the companion star, forcing carbon, oxygen and maybe helium within the star to fuse, triggering an explosion
  • It also appears that in many cases the white dwarf survives the explosion unlike in a Type Ia supernova where the white dwarf is completely destroyed
  • No Type Iax supernovae have been seen so far in elliptical galaxies, which are filled with old stars suggesting that Type Iax supernovae come from young star systems
  • Why Haven\’t We Seen Them Before?
  • Astronomers likely have discovered so few type Iax supernovae only because they are faint, releasing somewhere between 1% and 50% the energy of a type Ia supernova
  • The team has identified 25 examples of this new type of supernova, and there are estimates that for every 100 type Ia supernovae explosions that occur, there are about 31 type Iax supernovae, or roughly a third
  • Multimedia
  • YouTube | Type IA Supernovae | yoonoose
  • Further Reading / In the News
  • New Type of Star Explosion Discovered | Type Iax Supernovas | Space.com
  • ScienceShot: A New Class of Supernova – ScienceNOW | news.ScienceMag.org
  • New Kind of “Runt” Supernovae Could be Lurking Unseen | UniverseToday.com

— TWO-BYTE NEWS —

What’s the Buzz?

  • Magicicada is a genus of cicada with either a 13- or a 17-year lifespan, depending on species
  • It ranges from the Virginia/North Carolina border up through the northern end of the New York City suburbs
  • Brood II, also known as the \”East Coast Brood,\” is a 17-year cicada due for emergence this summer
  • Brood II
  • The Magicicada larvae live underground for nearly their entire lives, feeding on fluids from tree roots in the northeast United States
  • They then emerge with only a few weeks life in their lives to molt into adults, mate, lay eggs, and die.
  • It\’s not really known why they use this life cycle strategy
  • One theory is that such a long period between broods could fool predators, who likely won\’t have been alive (or won\’t remember) the previous emergence.
  • Tracking with Radiolab
  • The radio shows/podcast Radiolab has come up with a cicada tracker to pinpoint exactly when Brood II will begin \”swarmageddon.\”
  • When the soil eight inches below the surface reaches a steady temperature of 64 degrees F, the cicadas will begin their transformation
  • Radiolab will monitor the soil temperature using crowdsourcing data collection, you can report your findings to Radiolab, starting at the latest in mid-April
  • The interactive map they are putting together will help people track just when they\’ll emerge
  • Multimedia
  • YouTube | Amazing Cicada life cycle – Sir David Attenborough\’s Life in the Undergrowth | BBCWorldwide
  • Further Reading / In the News
  • Magicicada/org
  • Cicada Tracker | Radiolab
  • Radiolab Wants Your Help To Track The Once-Every-17-Year Cicada \”Swarmageddon\” | Popular Science

— VIEWER FEEDBACK —

Space and Television Entertainment

  • Scott Quinlan
  • Scott Quinlan seems a bit worried about the lack of space ships, real or science fiction
  • Answer
  • An edited version of “We Are The Explorers,” a video highlighting the past successes and future goals of the space administration — created by NASA and featuring an inspiring narration by Peter “Optimus Prime” Cullen — will be screened in several major U.S. cities during the premiere of Star Trek Into Darkness thanks to an overwhelmingly successful crowdfunding effort on Indiegogo.com.
  • Aerospace Industries Association of America) will use any funds donated during the next 29 days to reach its next target: getting the ad in at least one theater in every state in America for two weeks. In order for that to happen, a grand total of $94,000 will need to be reached
  • Announced on April 2nd, the project is now being conducted in partnership with Challenger Center for Space Science Education to further enhance and grow the crowdfund campaign
  • YouTube | We Are the Explorers | ReelNASA
  • YouTube | \”Our next destination awaits\” | We Are the Explorers | ReelNASA
  • Further Reading / In the News
  • WE ARE THE EXPLORERS: A movie trailer for our space program | indiegogo
  • NASA Trailer Achieves Crowdfunding Goal to Run Before Star Trek: Into Darkness | UniverseToday

— Updates —

Fossil Feather Color

  • New research shows that past reconstructions of the original colors of feathers in some fossil birds and dinosaurs may be flawed
  • There is evidence for the colors of feathers-especially melanin-based colors-can be altered during fossilization
  • The New Study
  • In modern birds, black, brown, and some reddish-brown colors are produced by tiny granules of the pigment melanin
  • These features-called melanosomes-are preserved in many fossil feathers, and their precise size and shape have been used to reconstruct the original colors of fossil feathers.
  • Scientists had no idea whether melanosomes could survive the fossilisation process intact, now experiments show that this is not the case.
  • Results from this study cast questions on studies of fossil feather color and suggest that some previous reconstructions of the original plumage colors of fossils may not be accurate
  • Experimental technique pioneered in the group\’s recent study on the colors of fossil insects simulated high pressures and temperatures that are found deep under the Earth\’s surface
  • The team then used feathers of different colors and from different species, but the geometry of the melanosomes in all feathers changed during the experiments
  • This study will lead to better interpretations of the original plumage colors of diverse feathered dinosaurs and fossil birds
  • Multimedia
  • YouTube | True Colors of Fossil Feathers in Doubt | LabEquipment
  • Further Reading / In the News
  • True colors of some fossil feathers now in doubt | Phys.org

— SPACECRAFT UPDATE—

Quick Trip to the Space Station

— CURIOSITY UPDATE —

  • Curiosity controllers plan to suspend commanding from April 4 to May 1.
  • NASA\’s Mars Exploration Rover Opportunity will send no commands between April 9 and April 26
  • The Mars Reconnaissance Orbiter will go into a record-only mode on April 4 until around May 1.
  • April, the Month of Rest
  • The positions of the planets in April will mean diminished communications between Earth and NASA\’s spacecraft at Mars as Mars will be passing almost directly behind the sun, from Earth\’s perspective. The sun can easily disrupt radio transmissions between the two planets during that near-alignment
  • To prevent an impaired command from reaching an orbiter or rover, mission controllers at NASA\’s Jet Propulsion Laboratory, Pasadena, Calif., are preparing to suspend sending any commands to spacecraft at Mars for weeks in April
  • The travels of Earth and Mars around the sun set up this arrangement, called a Mars solar conjunction, about once every 26 months, Mars solar conjunctions are not identical to each other. They can differ in exactly how close to directly behind the sun Mars gets, and they can differ in how active the sun is
  • Multimedia
  • YouTube | Mars in a Minute: What Happens When the Sun Blocks our Signal? | JPLnews
  • Image Galleries at JPL and Curiosity Mulimedia
  • Social Media
  • Curiosity Rover @MarsCuriosity

SCIENCE CALENDAR

Looking back

  • April 6, 1938 : 75 years ago : Teflon : Du Pont researcher Roy J. Plunkett and his technician Jack Rebok accidentally discovered the chemical compound polytetrafluoroethylene (PTFE), later marketed as Teflon. Plunkett was researching chemical reactions of the gas perfluoroethylene in order to synthesize new types of refrigerant gases. Rebok found an apparently defective cylinder of this gas, since no pressure was found when the valve was opened, even though the cylinder weight was the same as full cylinders. Rebok suggested sawing it open to investigate. Inside was a slippery white powder. Plunkett found it had unusual properties, a wonderful solid lubricant in powdered form, was chemically inert and had a very high melting point. He realized it was formed by an unexpected polymerization. It was patented on 4 Feb 1941.

Looking up this week

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