mindblowingscience:


Cells’ powerhouses were once energy parasites: Study upends current theories of how mitochondria began

Parasitic bacteria were the first cousins of the mitochondria that power cells in animals and plants — and first acted as energy parasites in those cells before becoming beneficial, according to a new University of Virginia study that used next-generation DNA sequencing technologies to decode the genomes of 18 bacteria that are close relatives of mitochondria.

The study appears this week in the online journal PLoS ONE, published by the Public Library of Science. It provides an alternative theory to two current theories of how simple bacterial cells were swallowed up by host cells and ultimately became mitochondria, the “powerhouse” organelles within virtually all eukaryotic cells — animal and plant cells that contain a nucleus and other features. Mitochondria power the cells by providing them with adenosine triphosphate, or ATP, considered by biologists to be the energy currency of life.
The origin of mitochondria began about 2 billion years ago and is one of the seminal events in the evolutionary history of life. However, little is known about the circumstances surrounding its origin, and that question is considered an enigma in modern biology.
"We believe this study has the potential to change the way we think about the event that led to mitochondria," said U.Va. biologist Martin Wu, the study’s lead author. "We are saying that the current theories — all claiming that the relationship between the bacteria and the host cell at the very beginning of the symbiosis was mutually beneficial — are likely wrong.
"Instead, we believe the relationship likely was antagonistic — that the bacteria were parasitic and only later became beneficial to the host cell by switching the direction of the ATP transport."
The finding, Wu said, is a new insight into an event in the early history of life on Earth that ultimately led to the diverse eukaryotic life we see today. Without mitochondria to provide energy to the rest of a cell, there could not have evolved such amazing biodiversity, he said.
"We reconstructed the gene content of mitochondrial ancestors, by sequencing DNAs of its close relatives, and we predict it to be a parasite that actually stole energy in the form of ATP from its host — completely opposite to the current role of mitochondria," Wu said.
In his study, Wu also identified many human genes that are derived from mitochondria — identification of which has the potential to help understand the genetic basis of human mitochondrial dysfunction that may contribute to several diseases, including Alzheimer’s disease, Parkinson’s disease and diabetes, as well as aging-related diseases.
In addition to the basic essential role of mitochondria in the functioning of cells, the DNA of mitochondria is used by scientists for DNA forensics, genealogy and tracing human evolutionary history.
Journal Reference:
Zhang Wang, Martin Wu. Phylogenomic Reconstruction Indicates Mitochondrial Ancestor Was an Energy Parasite. PLOS ONE, 2014 DOI:10.1371/journal.pone.0110685

mindblowingscience:

Cells’ powerhouses were once energy parasites: Study upends current theories of how mitochondria began

Parasitic bacteria were the first cousins of the mitochondria that power cells in animals and plants — and first acted as energy parasites in those cells before becoming beneficial, according to a new University of Virginia study that used next-generation DNA sequencing technologies to decode the genomes of 18 bacteria that are close relatives of mitochondria.

The study appears this week in the online journal PLoS ONE, published by the Public Library of Science. It provides an alternative theory to two current theories of how simple bacterial cells were swallowed up by host cells and ultimately became mitochondria, the “powerhouse” organelles within virtually all eukaryotic cells — animal and plant cells that contain a nucleus and other features. Mitochondria power the cells by providing them with adenosine triphosphate, or ATP, considered by biologists to be the energy currency of life.

The origin of mitochondria began about 2 billion years ago and is one of the seminal events in the evolutionary history of life. However, little is known about the circumstances surrounding its origin, and that question is considered an enigma in modern biology.

"We believe this study has the potential to change the way we think about the event that led to mitochondria," said U.Va. biologist Martin Wu, the study’s lead author. "We are saying that the current theories — all claiming that the relationship between the bacteria and the host cell at the very beginning of the symbiosis was mutually beneficial — are likely wrong.

"Instead, we believe the relationship likely was antagonistic — that the bacteria were parasitic and only later became beneficial to the host cell by switching the direction of the ATP transport."

The finding, Wu said, is a new insight into an event in the early history of life on Earth that ultimately led to the diverse eukaryotic life we see today. Without mitochondria to provide energy to the rest of a cell, there could not have evolved such amazing biodiversity, he said.

"We reconstructed the gene content of mitochondrial ancestors, by sequencing DNAs of its close relatives, and we predict it to be a parasite that actually stole energy in the form of ATP from its host — completely opposite to the current role of mitochondria," Wu said.

In his study, Wu also identified many human genes that are derived from mitochondria — identification of which has the potential to help understand the genetic basis of human mitochondrial dysfunction that may contribute to several diseases, including Alzheimer’s disease, Parkinson’s disease and diabetes, as well as aging-related diseases.

In addition to the basic essential role of mitochondria in the functioning of cells, the DNA of mitochondria is used by scientists for DNA forensics, genealogy and tracing human evolutionary history.

Journal Reference:

Zhang Wang, Martin Wu. Phylogenomic Reconstruction Indicates Mitochondrial Ancestor Was an Energy ParasitePLOS ONE, 2014 DOI:10.1371/journal.pone.0110685

(via afro-dominicano)

thewaydelphinesayscosima:

I’ve been reading Endless Forms Most Beautiful and this part from NDT’s Cosmos came to mind. 

(via fyeah-degrasse-tyson)

into-theuniverse:

Star Cluster Melotte 15 in the Heart Nebula // IC 1805

into-theuniverse:

Star Cluster Melotte 15 in the Heart Nebula // IC 1805

(Source: apod.nasa.gov)

bpod-mrc:

18 October 2014
Catching the Culprit
The first step towards treatment is to identify the cause of the problem, but when the disease is poorly understood, or when symptoms can be attributed to multiple suspects, diagnosis can feel more like detective work. Pictured are cells of the fungus Madurella mycetomatis, just one of a range of micro-organisms which cause serious subcutaneous infections known as mycetoma. While bacterial and fungal mycetoma produce similar symptoms, they require very different treatments; even within each group, the response varies from species to species. Identifying the specific culprit is thus crucial to recovery, yet many species can’t be distinguished even when the organism is isolated for imaging or other chemical tests. Genetic analysis is the most accurate diagnostic tool, but this expensive technique is often unavailable in the developing nations where mycetoma is common; facilitating access to this technology will be key to improving the treatment of this condition.
Written by Emmanuelle Briolat
—
Image by Wendy van de Sande and colleaguesErasmus Medical Center, The NetherlandsOriginally published under a Creative Commons Licence (BY 4.0)Research published in PLOS Neglected Tropical Diseases, July 2014
—
You can also follow BPoD on Twitter and Facebook

bpod-mrc:

18 October 2014

Catching the Culprit

The first step towards treatment is to identify the cause of the problem, but when the disease is poorly understood, or when symptoms can be attributed to multiple suspects, diagnosis can feel more like detective work. Pictured are cells of the fungus Madurella mycetomatis, just one of a range of micro-organisms which cause serious subcutaneous infections known as mycetoma. While bacterial and fungal mycetoma produce similar symptoms, they require very different treatments; even within each group, the response varies from species to species. Identifying the specific culprit is thus crucial to recovery, yet many species can’t be distinguished even when the organism is isolated for imaging or other chemical tests. Genetic analysis is the most accurate diagnostic tool, but this expensive technique is often unavailable in the developing nations where mycetoma is common; facilitating access to this technology will be key to improving the treatment of this condition.

Written by Emmanuelle Briolat

Image by Wendy van de Sande and colleagues
Erasmus Medical Center, The Netherlands
Originally published under a Creative Commons Licence (BY 4.0)
Research published in PLOS Neglected Tropical Diseases, July 2014

You can also follow BPoD on Twitter and Facebook

distant-traveller:

Turquoise-tinted plumes in the Large Magellanic Cloud


The brightly glowing plumes seen in this image are reminiscent of an underwater scene, with turquoise-tinted currents and nebulous strands reaching out into the surroundings.



However, this is no ocean. This image actually shows part of the Large Magellanic Cloud (LMC), a small nearby galaxy that orbits our galaxy, the Milky Way, and appears as a blurred blob in our skies. The NASA/ESA Hubble Space Telescope has peeked many times into this galaxy, releasing stunning images of the whirling clouds of gas and sparkling stars.
This image shows part of the Tarantula Nebula’s outskirts. This famously beautiful nebula, located within the LMC, is a frequent target for Hubble.
In most images of the LMC the colour is completely different to that seen here. This is because, in this new image, a different set of filters was used. The customary R filter, which selects the red light, was replaced by a filter letting through the near-infrared light. In traditional images, the hydrogen gas appears pink because it shines most brightly in the red. Here however, other less prominent emission lines dominate in the blue and green filters.
This data is part of the Archival Pure Parallel Project (APPP), a project that gathered together and processed over 1000 images taken using Hubble’s Wide Field Planetary Camera 2, obtained in parallel with other Hubble instruments. Much of the data in the project could be used to study a wide range of astronomical topics, including gravitational lensing and cosmic shear, exploring distant star-forming galaxies, supplementing observations in other wavelength ranges with optical data, and examining star populations from stellar heavyweights all the way down to solar-mass stars.

Image credit: ESA/Hubble & NASA; Acknowledgement: Josh Barrington

distant-traveller:

Turquoise-tinted plumes in the Large Magellanic Cloud

The brightly glowing plumes seen in this image are reminiscent of an underwater scene, with turquoise-tinted currents and nebulous strands reaching out into the surroundings.

However, this is no ocean. This image actually shows part of the Large Magellanic Cloud (LMC), a small nearby galaxy that orbits our galaxy, the Milky Way, and appears as a blurred blob in our skies. The NASA/ESA Hubble Space Telescope has peeked many times into this galaxy, releasing stunning images of the whirling clouds of gas and sparkling stars.

This image shows part of the Tarantula Nebula’s outskirts. This famously beautiful nebula, located within the LMC, is a frequent target for Hubble.

In most images of the LMC the colour is completely different to that seen here. This is because, in this new image, a different set of filters was used. The customary R filter, which selects the red light, was replaced by a filter letting through the near-infrared light. In traditional images, the hydrogen gas appears pink because it shines most brightly in the red. Here however, other less prominent emission lines dominate in the blue and green filters.

This data is part of the Archival Pure Parallel Project (APPP), a project that gathered together and processed over 1000 images taken using Hubble’s Wide Field Planetary Camera 2, obtained in parallel with other Hubble instruments. Much of the data in the project could be used to study a wide range of astronomical topics, including gravitational lensing and cosmic shear, exploring distant star-forming galaxies, supplementing observations in other wavelength ranges with optical data, and examining star populations from stellar heavyweights all the way down to solar-mass stars.

Image credit: ESA/Hubble & NASA; Acknowledgement: Josh Barrington

(Source: spacetelescope.org, via startalkradio)

ohstarstuff:

What You Need to Know About Mars Comet Siding Spring

  • On Sunday, October 19th, Comet C/2013 A1, aka Siding Spring, will pass within about 87,000 miles of the Red Planet.

  • The distance the comet will be from Mars is less than half the distance between Earth and our moon and less than one-tenth the distance of any known comet flyby of Earth.

  • Siding Spring, whose core is 0.5 to 5 miles wide, probably formed somewhere between Jupiter and Neptune about 4.6 billion years ago — just a few million years after the solar system began coming together. Scientists believe Siding Spring had a close encounter with one of these planets and was booted out into the Oort Cloud

  • A million years ago or so, a star passing by the Oort Cloud is thought to have jolted the comet’s orbit again, sending it on its first-ever trip into the inner solar system.

  • Comets from the Oort cloud are both ancient and rare. Since this is Comet Siding Spring’s first trip through the inner solar system, scientists are excited to learn more about its composition and the effects of its gas and dust on the Mars upper atmosphere.

  • NASA does not think the comet hit the Red Planet, but comets spew out a trail of dust and gas, and that could damage the fleet of spacecraft orbiting Mars. Just to be safe, NASA will move the Mars Odyssey orbiter, Mars Reconnaissance Orbiter (MRO), and the new Mars Atmosphere and Volatile EvolutioN (MAVEN) to the other side of the planet as the comet approaches.

  • The Mars orbiters will take pictures and collect data on the comet as it flys by. Several Earth-based and space telescopes, including the Hubble Space Telescope, also will take pictures. Here is the full list of NASA assets observing Siding Spring

  • The comet was first discovered in January 2013 by Robert McNaught at the Siding Spring Observatory in Australia.

  • Great article from Space.com on how to view the comet from Earth 

(Source: mars.nasa.gov, via galaxyclusters)

distant-traveller:

Earth and Mars captured together in one photo from lunar orbit



The Lunar Reconnaissance Orbiter turned for a quick look at Earth and one of our closest planetary neighbors—Mars.

Image credit: NASA/GSFC/Arizona State University

distant-traveller:

Earth and Mars captured together in one photo from lunar orbit

The Lunar Reconnaissance Orbiter turned for a quick look at Earth and one of our closest planetary neighbors—Mars.

Image credit: NASA/GSFC/Arizona State University

(via thedemon-hauntedworld)

asapscience:

Unfortunately, this is American Ebola logic. 
For more on the hysteria surrounding Ebola, we recommend listening to this week’s episode of NPR’s On The Media to help dispel fears. 
(@SciencePorn)

asapscience:

Unfortunately, this is American Ebola logic. 

For more on the hysteria surrounding Ebola, we recommend listening to this week’s episode of NPR’s On The Media to help dispel fears. 

(@SciencePorn)

ronbeckdesigns:

giant devil flower mantids (idolomantis diabolica)  Found on fbcdn-sphotos-c-a.akamaihd.net

ronbeckdesigns:

giant devil flower mantids (idolomantis diabolica)
Found on fbcdn-sphotos-c-a.akamaihd.net

(via arrowtongue)

scienceyoucanlove:

Portuguese Man-of-War

Anyone unfamiliar with the biology of the venomous Portuguese man-of-war would likely mistake it for a jellyfish. Not only is it not a jellyfish, it’s not even an “it,” but a “they.” The Portuguese man-of-war is a siphonophore, an animal made up of a colony of organisms working together.

The man-of-war comprises four separate polyps. It gets its name from the uppermost polyp, a gas-filled bladder, or pneumatophore, which sits above the water and somewhat resembles an old warship at full sail. Man-of-wars are also known as bluebottles for the purple-blue color of their pneumatophores.

The tentacles are the man-of-war’s second organism. These long, thin tendrils can extend 165 feet (50 meters) in length below the surface, although 30 feet (10 meters) is more the average. They are covered in venom-filled nematocysts used to paralyze and kill fish and other small creatures. For humans, a man-of-war sting is excruciatingly painful, but rarely deadly. But beware—even dead man-of-wars washed up on shore can deliver a sting.

Muscles in the tentacles draw prey up to a polyp containing the gastrozooids or digestive organisms. A fourth polyp contains the reproductive organisms.

Man-of-wars are found, sometimes in groups of 1,000 or more, floating in warm waters throughout the world’s oceans. They have no independent means of propulsion and either drift on the currents or catch the wind with their pneumatophores. To avoid threats on the surface, they can deflate their air bags and briefly submerge.

source

first photo from wiki commons, second photo source

(via ocean-depths)

we-are-star-stuff:


Why Do Your Pupils Get Larger When You’re On Drugs?
Normally, our pupils dilate in response to changing light; as it gets darker, our pupils get larger. But they expand in size for other reasons as well, including when we’re sexually aroused and when we’re performing complex cognitive tasks. But it’s also known that certain medications — including illicit drugs — can cause pupils to get larger. Here’s why.
Pupil dilation, what’s also referred to as mydriasis, happens when one of two muscle groups become activated, namely the iris sphincter (yes, that’s what it’s called) and the iris dilator. The sphincter response is triggered by the parasympathetic nervous system (what regulates our autonomic bodily processes when we’re at rest), and the dilator by the sympathetic nervous symptom (what controls physiological responses requiring a quick response — like fight-or-flight).
Needless to say, psychotropic drugs can have a profound effect on both of these systems.
Depending on the type of drug taken, therefore, either muscle group can become engaged. Essentially, if a drug can trigger a parasympathetic or sympathetic response, there’s a good chance that it will also impact on pupil dilation. Specifically, mydriasis can be caused by stimulants and any drug that influences the adrenal glands — what can trigger certain parasympathetic responses.
For example, drugs like MDMA, ecstasy, cocaine, amphetamines, and some antidepressants (like SSRIs) can increase serotonin levels in the brain — a crucial neurotransmitter that regulates mood, including feelings of happiness and well-being. Serotonin agonizes to the 5-HT2A receptors in the brain — what has the downstream effect of triggering the mydriasis response, and in some cases, psychedelic episodes.
Consequently, mydriasis also occurs in people who take serotonin-inducing psychedelics like LSD, mescaline, and psilocybin.
Drugs that trigger the release of dopamine, a related neurotransmitter, can also induce mydriasis. Marijuana is a good example. Dopamine cause pupils to dilate by exciting the adrenergic receptors, what in turn increases adrenaline (which the autonomic nervous system is sensitive to).
It’s important to remember that not all drugs will produce the same degree of pupil dilation. For example, MDMA will have a much more profound effect on pupil dilation than, say, an antidepressant.
And interestingly, other drugs, like opiates, cause the opposite effect — pupil contraction, or what’s known as miosis.
[Continue Reading→]

we-are-star-stuff:

Why Do Your Pupils Get Larger When You’re On Drugs?

Normally, our pupils dilate in response to changing light; as it gets darker, our pupils get larger. But they expand in size for other reasons as well, including when we’re sexually aroused and when we’re performing complex cognitive tasks. But it’s also known that certain medications — including illicit drugs — can cause pupils to get larger. Here’s why.

Pupil dilation, what’s also referred to as mydriasis, happens when one of two muscle groups become activated, namely the iris sphincter (yes, that’s what it’s called) and the iris dilator. The sphincter response is triggered by the parasympathetic nervous system (what regulates our autonomic bodily processes when we’re at rest), and the dilator by the sympathetic nervous symptom (what controls physiological responses requiring a quick response — like fight-or-flight).

Needless to say, psychotropic drugs can have a profound effect on both of these systems.

Depending on the type of drug taken, therefore, either muscle group can become engaged. Essentially, if a drug can trigger a parasympathetic or sympathetic response, there’s a good chance that it will also impact on pupil dilation. Specifically, mydriasis can be caused by stimulants and any drug that influences the adrenal glands — what can trigger certain parasympathetic responses.

For example, drugs like MDMA, ecstasy, cocaine, amphetamines, and some antidepressants (like SSRIs) can increase serotonin levels in the brain — a crucial neurotransmitter that regulates mood, including feelings of happiness and well-being. Serotonin agonizes to the 5-HT2A receptors in the brain — what has the downstream effect of triggering the mydriasis response, and in some cases, psychedelic episodes.

Consequently, mydriasis also occurs in people who take serotonin-inducing psychedelics like LSD, mescaline, and psilocybin.

Drugs that trigger the release of dopamine, a related neurotransmitter, can also induce mydriasis. Marijuana is a good example. Dopamine cause pupils to dilate by exciting the adrenergic receptors, what in turn increases adrenaline (which the autonomic nervous system is sensitive to).

It’s important to remember that not all drugs will produce the same degree of pupil dilation. For example, MDMA will have a much more profound effect on pupil dilation than, say, an antidepressant.

And interestingly, other drugs, like opiates, cause the opposite effect — pupil contraction, or what’s known as miosis.

[Continue Reading→]

sci-universe:

NGC 7293, better known as the Helix nebula, is the nearest example of a planetary nebula, which is the eventual fate of a star, like our own Sun, as it approaches the end of its life. As it runs out of fuel, the star expels its outer envelope of gas outward to form a nebula like the Helix.
Images: different views of NGC 7293. Credit: ESA, NASA, ESO.

(via galaxyclusters)

earthlynation:

Eyed Hawkmoth (by roychurchill)

earthlynation:

Eyed Hawkmoth (by roychurchill)

fuckyeahaquaria:

Peacock Gudgeon Eggs | Tateurndina ocellicauda
(by novocainstain)

fuckyeahaquaria:

Peacock Gudgeon Eggs | Tateurndina ocellicauda

(by novocainstain)

(via ocean-depths)