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Evolution is as complicated as 1-2-3

Evolution is as complicated as 1-2-3 | biosc&med | Scoop.it

A team of researchers at MSU has documented the step-by-step process in which organisms evolve new functions. The results are revealed through an in-depth, genomics-based analysis that decodes how E. coli bacteria figured out how to supplement a traditional diet of glucose with an extra course of citrate.

 

“It’s pretty nifty to see a new biological function evolve,” said Zachary Blount, postdoctoral researcher in MSU’s BEACON Center for the Study of Evolution in Action. “The first citrate-eaters were just barely able to grow on the citrate, but they got much better over time. We wanted to understand the changes that allowed the bacteria to evolve this new ability. We were lucky to have a system that allowed us to do so.” Normal E. coli can’t digest citrate when oxygen is present. In fact, it’s a distinct hallmark of E. coli. They can’t eat citrate because E. coli don’t express the right protein to absorb citrate molecules.

 

To decipher the responsible mutations, Blount worked with Richard Lenski, MSU Hannah Distinguished Professor of Microbiology and Molecular Genetics. Lenski’s long-term experiment, cultivating cultures of fast-growing E. coli, was launched in 1988 and has allowed him and his teammates to study more than more than 56,000 generations of bacterial evolution. The experiment demonstrates natural selection at work. And because samples are frozen and available for later study, when something new emerges scientists can go back to earlier generations to look for the steps that happened along the way.

 

The first stage was potentiation, when the E. coli accumulated at least two mutations that set the stage for later events. The second step, actualization, is when the bacteria first began eating citrate, but only just barely nibbling at it. The final stage, refinement, involved mutations that greatly improved the initially weak function. This allowed the citrate eaters to wolf down their new food source and to become dominant in the population.

 

“We were particularly excited about the actualization stage,” Blount said. “The actual mutation involved is quite complex. It re-arranged part of the bacteria’s DNA, making a new regulatory module that had not existed before. This new module causes the production of a protein that allows the bacteria to bring citrate into the cell when oxygen is present. That is a new trick for E. coli.”


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Οι Νεάντερταλ μας χάρισαν τον... εθισμό στο κάπνισμα - Το Βήμα Online

Οι Νεάντερταλ μας χάρισαν τον... εθισμό στο κάπνισμα - Το Βήμα Online | biosc&med | Scoop.it
Το Βήμα Online
Οι Νεάντερταλ μας χάρισαν τον...
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Οι Νεάντερταλ μας χάρισαν τον... εθισμό στο κάπνισμαΓενετικές μελέτες αποκαλύπτουν επίσης ότι μας κληροδότησαν γονίδια που συνδέονται με αυτοάνοσες διαταραχές
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Πλοήγηση στη συλλογή

Πλοήγηση στη συλλογή | biosc&med | Scoop.it
ΙΕΠ: Ψηφιοποιημένο το περιεχόμενο χιλιάδων σχολικών βιβλίων από την ίδρυση του ελληνικού κράτους

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Τι περιμένουμε στην Επιστήμη το 2017 (ΒΗΜΑ)

Τι περιμένουμε στην Επιστήμη το 2017 (ΒΗΜΑ) | biosc&med | Scoop.it
Τι περιμένουμε στην Επιστήμη το 2017 - Konstantinos Floridis – Google+
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Πόση είναι η μέση διάρκεια ζωής ενός τεχνολογικά προηγμένου πολιτισμού;

Πόση είναι η μέση διάρκεια ζωής ενός τεχνολογικά προηγμένου πολιτισμού; | biosc&med | Scoop.it
Το ερώτημα στον τίτλο είναι ένα από τα τρία πιο σημαντικά ερωτήματα προκειμένου να μπορέσουμε να εκτιμήσουμε επιστημονικά την πιθανότητα να υπάρχει ζωή κάπου στο σύμπαν. Αυτό γράφει ο Χάρης Βάρβογλης, ομότιμος καθηγητής Τμήματος Φυσικής ΑΠΘ (Τομέας Αστρονομίας και Αστροφυσικής) στο εξαιρετικά κατατοπιστικό και ενδιαφέρον προλογικό σημείωμά του στον τόμο «Πέντε δισεκατομμύρια χρόνια μοναξιά» του…

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tovima.gr - Νευρώνες από κύτταρα δέρματος!

tovima.gr - Νευρώνες από κύτταρα δέρματος! | biosc&med | Scoop.it
Νευρικά κύτταρα του εγκεφάλου (νευρώνες) από κύτταρα ανθρώπινου δέρματος δημιούργησαν στο εργαστήριο επιστήμονες του Ελληνικού Ινστιτούτου Παστέρ
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Διάλεξη για τον πλησιέστερο κατοικήσιμο εξωπλανήτη

Διάλεξη για τον πλησιέστερο κατοικήσιμο εξωπλανήτη | biosc&med | Scoop.it
... από τον επικεφαλής του Τμήματος Εκπαίδευσης και Διάχυσης των Επιστημών του Ευρωπαϊκού Νότιου Αστεροσκοπείου (ΕSO) Lars Lindberg Christensen Εκδήλωση στο Νέο Ψηφιακό Πλανητάριο, την Δευτέρα 19 Σεπτεμβρίου 2016 Με αφορμή την φθινοπωρινή ισημερία το Νέο Ψηφιακό Πλανητάριο έχει προσκαλέσει τον επικεφαλής του Τμήματος Εκπαίδευσης και Διάχυσης των Επιστημών του Ευρωπαϊκού Νότιου Αστεροσκοπείου (European Southern…

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Αναζητώντας τη σκοτεινή ύλη μέσω του LHC

Αναζητώντας τη σκοτεινή ύλη μέσω του LHC | biosc&med | Scoop.it
Πριν από λίγες ημέρες τέθηκε ξανά σε λειτουργία ο LHC, ο μεγαλύτερος σωματιδιακός επιταχυντής που υπάρχει πάνω στη Γη. Οι ένα δισεκατομμύριο συγκρούσεις πρωτονίων το δευτερόλεπτο -6 φορές μεγαλύτερος αριθμός δεδομένων απ’ ό,τι το 2015!- ίσως να επιτρέψουν στους φυσικούς να λύσουν το αίνιγμα της σύστασης της σκοτεινής ύλης.

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Ο Δ. Νανόπουλος για την ανακάλυψη των βαρυτικών κυμάτων

Ο Δ. Νανόπουλος για την ανακάλυψη των βαρυτικών κυμάτων | biosc&med | Scoop.it
Συνέντευξη στον Μάκη Προβατά (ΒΗΜΑ FM) (από το 2:90 έως 18:05) Με την ευκαιρία να αναφέρουμε ότι η ανακοίνωση της ανίχνευσης των βαρυτικών κυμάτων από το LIGO συνοδεύθηκε από μια δεύτερη ανακοίνωση από το διαστημικό τηλεσκόπιο ακτινοβολίας γ Fermi. Σύμφωνα με αυτή 0,4 δευτερόλεπτα μετά την παρατήρηση των βαρυτικών κυμάτων που προκλήθηκαν από την συγχώνευση των μαύρων…

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Περιμένοντας τους εξωγήινους

Περιμένοντας τους εξωγήινους | biosc&med | Scoop.it
Περιμένοντας τους βαρβάρους - ΔΙΟΝΥΣΗΣ Π. ΣΙΜΟΠΟΥΛΟΣ* Στις αρχές του περασμένου μήνα η Ελεν Στόφαν, επικεφαλής επιστήμων της NASA, δήλωσε ότι «μέσα σε μία δεκαετία πρόκειται να έχουμε ισχυρές ενδ...

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Μαθηματικό μοντέλο εξηγεί την προέλευση της ζωής

Μαθηματικό μοντέλο εξηγεί την προέλευση της ζωής | biosc&med | Scoop.it
Χρησιμοποιεί στοιχεία από τη θεωρία Ginzburg–Landau για την υπεραγωγιμότητα Μία διεθνής ομάδα φυσικών δημιούργησε μαθηματικά μοντέλα βιολογικών καταστάσεων χρησιμοποιώντας ενεργειακά κύματα με την ...

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Scientists find hydrogen production in an extremophile bacterium (Halanaerobium hydrogeninformans)

Scientists find hydrogen production in an extremophile bacterium (Halanaerobium hydrogeninformans) | biosc&med | Scoop.it

Dr. Melanie Mormile, professor of biological sciences at Missouri S&T, and her team discovered the bacterium "Halanaerobium hydrogeninformans" in Soap Lake, Washington. It can "produce hydrogen under saline and alkaline conditions in amounts that rival genetically modified organisms," Mormile says.


"Usually, I tend to study the overall microbial ecology of extreme environments, but this particular bacterium has caught my attention," Mormile says. "I intend to study this isolate in greater detail."


Mormile, an expert in the microbial ecology of extreme environments, wasn't searching for a bacterium that could produce hydrogen. Instead, she first became interested in bacteria that could help clean up the environment, especially looking at the extremophiles found in Soap Lake.


An extremophile is a microorganism that lives in conditions of extreme temperature, acidity, alkalinity or chemical concentration. Living in such a hostile environment, "Halanaerobium hydrogeninformans" has metabolic capabilities under conditions that occur at some contaminated waste sites.


With "Halanaerobium hydrogeninformans," she expected to find an iron-reducing bacterium and describe a new species. What she found was a new species of bacterium that can produce hydrogen and 1, 3-propanediol under high pH and salinity conditions that might turn out to be valuable industrially. An organic compound, 1, 3-propenediol can be formulated into industrial products including composites, adhesives, laminates and coatings. It's also a solvent and can be used as antifreeze.


The infrastructure isn't in place now for hydrogen to replace gasoline as a fuel for planes, trains and automobiles. But if hydrogen becomes an alternative to gasoline, "Halanaerobium hydrogeniformans," mass-produced on an industrial scale, might be one solution – although it won't be a solution anytime soon.


Via Dr. Stefan Gruenwald
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Βίντεο: ερευνητές ανίχνευσαν πιθανό σήμα από σκοτεινή ύλη

Βίντεο: ερευνητές ανίχνευσαν πιθανό σήμα από σκοτεινή ύλη | biosc&med | Scoop.it
(νεώτερη ενημέρωση 12-12-2014, προς το τέλος της ανάρτησης) Συνήθως όταν αναφερόμαστε στη σκοτεινή ύλη ένα πέπλο μυστηρίου καλύπτει τα διάφορα εξωτικά (και άγνωστα) σωματίδια που την αποτελούν. Tα ...

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Rapid interventions key to preventing worldwide Ebola outbreak

Rapid interventions key to preventing worldwide Ebola outbreak | biosc&med | Scoop.it

To avoid the spread of Ebola and far worse scenarios, quick and forceful implementation of control interventions are necessary, according to new research published today in the scientific journal Eurosurveillance.

 

Analyzing Ebola cases in Nigera, a country that has had success in containing the disease, researchers estimated the rate of fatality, transmission progression, proportion of health care workers infected and the impact of control interventions on the size of the epidemic.

 

The study's findings show that Ebola transmission is dramatically influenced by how rapidly control measures are put in place.

 

"Rapid and forceful control measures are necessary, as is demonstrated by the Nigerian success story," said Arizona State University's  Gerardo Chowell, senior author of the paper. "This is critically important for countries in the West African region that are not yet affected by the Ebola epidemic, as well as for countries in other regions of the world that risk importation of the disease."

 

The largest Ebola outbreak to date is ongoing in West Africa, with approximately 8,011 reported cases that include more than 3,857 deaths as of Oct. 5. However, just 20 Ebola cases have been reported in Nigeria, with no new cases reported since Sept.5.

 

Ebola transmission is dramatically influenced by how rapidly control measures are put in place, as researchers found that the projected effect of control interventions in Nigeria ranged from 15-106 cases when interventions are put in place on day 3; 20-178 cases when implemented on day 10; 23-282 cases on day 20; 60-666 cases on day 30; 39-1599 cases on day 40; and 93-2771 on day 50.

 

"There is brief window of time when a rapid and forceful intervention in terms of relentless contact tracing and isolation pays off handsomely and the transmission is effectively halted and the outbreak dies out," said co-author professor Lone Simonsen, of the Milken Institute School of Public Health at the George Washington University in Washington D.C.

 

The person who was initially infected generated 12 secondary cases, in the first generation of the disease; five secondary cases were generated from those 12 in the second generation; and two secondary cases in the third generation, leading to a rough empirical estimate of the reproduction number according to disease generation declining from 12 during the first generation, to approximately 0.4 during the second and third disease generations. Recent estimates of the reproduction number for the ongoing Ebola epidemic in Sierra Leone and Liberia range between 1.5 and 2 (two new cases for each single case), indicating that the outbreak is yet to be brought under control.

 


Via Dr. Stefan Gruenwald
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Πως σχηματίστηκαν οι μαύρες τρύπες που ανίχνευσε το LIGO;

Πως σχηματίστηκαν οι μαύρες τρύπες που ανίχνευσε το LIGO; | biosc&med | Scoop.it
Τον Σεπτέμβριο του 2015, το πείραμα advanced LIGO έγραψε ιστορία στη φυσική, ανιχνεύοντας για πρώτη φορά βαρυτικά κύματα. Με αυτό τον τρόπο, επιβεβαίωσε έπειτα από 100 χρόνια την τελευταία πρόβλεψη της Γενικής Θεωρίας της Σχετικότητας που δεν είχε επαληθευτεί, σύμφωνα με την οποία η κίνηση των σωμάτων δημιουργεί διαταραχές στο χωροχρονικό συνεχές, που διαδίδονται με…

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Biomedicine - Google+

Biomedicine - Google+ | biosc&med | Scoop.it
Biomedicine - Articles and updates about Medicine and Biology (some articles in Greek and some in English) - Articles and updates about Medicine and Biology
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HIV SYMPTOMS (HIV, AIDS) - All about health -

"All about health" channel - https://www.youtube.com/channel/UC22b8emDhAteSOqdINnn_nQ HIV SYMPTOMS (HIV, AIDS) video - https://youtu.be/epLQPqKFF6g Mayb
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Οι New York Times και η θεωρία της Μεγάλης Έκρηξης

Οι New York Times και η θεωρία της Μεγάλης Έκρηξης | biosc&med | Scoop.it
Ο Nichοlas Bakalar έψαξε (και βρήκε) στα παλιά φύλλα της εφημερίδας "The New York Times" τις πρώτες αναφορές σχετικά με την θεωρία της Μεγάλης Έκρηξης. To 1927, o Georges Lemaître, ένας ρωμαιοκαθολικός ιερέας και αστρονόμος από το Βέλγιο, πρότεινε μια νέα θεωρία για τη γέννηση του Σύμπαντος, την «υπόθεση του πρωταρχικού ατόμου» . Η θεωρία αυτή βελτιώθηκε…

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The Viruses That Made Us Human — NOVA Next | PBS

The Viruses That Made Us Human — NOVA Next | PBS | biosc&med | Scoop.it
Viruses that infected our ancestors provided the genetic foundations for many traits that define us.

Via Neelima Sinha
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Δημήτρης Νανόπουλος - Το Σύμπαν

Καλεσμένος μας είναι ο Δημήτρης Νανόπουλος.

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The Future of Gravitational Wave Astronomy

The Future of Gravitational Wave Astronomy | biosc&med | Scoop.it
Fully opening this new window on the universe will take decades—even centuries

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Complete genome of all strains of the gibbon ape leukemia virus sequenced

Complete genome of all strains of the gibbon ape leukemia virus sequenced | biosc&med | Scoop.it

Berlin-based scientists have sequenced the complete genome of all five identified strains of the gibbon ape leukemia virus (GALV). The scientists were able to prove that selection has shaped parts of the genome of this group ...

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Medicine vocabulary with pictures English lesson

Medicine vocabulary with pictures English lesson | biosc&med | Scoop.it
Learning medicine vocabulary using pictures and how to have a basic conversation about medicine

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Learning Basic English vocabulary and grammar's curator insight, March 20, 2015 11:10 PM

Learning medicine vocabulary using pictures and how to have a basic conversation about medicine

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Viruses In Our Genome: Forty Million Years In the Making

Viruses In Our Genome: Forty Million Years In the Making | biosc&med | Scoop.it

Each year, billions of people get infected with viruses–with common ones like influenza and cold viruses, and rarer ones like polio and Ebola. The viruses don’t stay all that long inside of us. In most cases, our immune systems wipe them out, except for a few refugees that manage to escape to a new host and keep their species alive. In some cases, the viruses kill their unfortunate hosts, and end their own existence as well. But in some exquisitely rare cases, viruses meld with the genome of their hosts and become part of the genetic legacy their hosts pass down to future generations.


Scientists know this melding has happened because viruses have distinctive genes. When scientists scan the human genome, they sometimes come across a stretch of DNA that bears the hallmarks of viruses. The easiest type of virus to recognize are retroviruses, a group that includes HIV. Retroviruses make copies of themselves by infecting cells and then using an enzyme to insert their genes into their host cell’s DNA. The cell then reads the inserted DNA and makes new molecules that assemble into new viruses.


Humans carry about 100,000 pieces of DNA that came from retroviruses–known as endogenous retroviruses. All told, they come to an estimated 5 to 8 percent of the entire human genome. That’s several times more DNA that makes up all 20,000 of our protein-coding genes.


Gkikas Magiorkinis, a University of Oxford virologist, and his colleagues have now carried out large-scale survey of endogenous retroviruses in humans, apes, and Old World monkeys–a group of species that all descend from a common primate ancestor that lived some 40 million years ago. They catalogued the viruses in each species and compared them to the versions in the other primates. They were able to reconstruct the history of our viral DNA in unprecedented detail, even coming up with estimates for the rate at which the viruses inserted new copies into our genome.


The scientists can trace our viral DNA to 30 to 35 separate invasions. Once each virus established itself in our ancestors’ DNA, it produced copies of itself scattered through the genome. The rate at which new copies were inserted rose and fell over time, and at different rates in different branches of the primate tree. Here’s an overall look at the history of the viruses. 


Our monkey-like ancestors 40 million years ago acquired new virus copies at a fast clip–much faster than in our own lineage in the past couple million years. One virus in particular, known as HERV-H, was responsible for most of the new copies. It may have evolved adaptations that made it into a superspreader inside the genome.


In the past million years, only a single virus has continued to multiply–known as HERV-K. Today, you can find some HERV-K copies in some people and not in others. The pattern of these copies suggests that as recently as 250,000 years ago, HERV-K was still making new copies.


It’s possible that HERV-K is completely dead now. There’s no evidence that HERV-K or any other endogenous retrovirus is actively spreading or causing cancer. It’s hard to say at this point why humans have put the brakes on endogenous retroviruses. But Magiorkinis has one suggestion: our ancestors may have reduced their odds of picking up new viruses.


Via Dr. Stefan Gruenwald
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Πως δημιουργείται αντιύλη κατά τη διάρκεια των καταιγίδων

Πως δημιουργείται αντιύλη κατά τη διάρκεια των καταιγίδων | biosc&med | Scoop.it
Το διαστημικό τηλεσκόπιο ακτίνων-γ Fermi της NASA ανίχνευσε αντιύλη που παράγεται από τις γήινες καταιγίδες. Το φαινόμενο αυτό παρατηρείται για πρώτη φορά. Οι επιστήμονες πιστεύουν ότι τα σωματίδια...

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Η παρατήρηση του νάνου πλανήτη Makemake

Η παρατήρηση του νάνου πλανήτη Makemake | biosc&med | Scoop.it
Ο πέμπτος πλανήτης-νάνος του ηλιακού μας συστήματος «φωτογραφίζεται» για πρώτη φορά από τους επιστήμονες Οι περισσότεροι πιθανότατα δεν έχετε ακούσει τίποτε για αυτόν, όμως ο Μακεμάκε, εκτός από θε...

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Konstantinos Floridis's insight:

Rosetta,philae,  Churyumov _  Gerasimenko και τώρα Μακεμακε.
Εντερπράιζ γίναμε :)

 

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Το παράδοξο της γάτας του Schrödinger (Ι)

Το παράδοξο της γάτας του Schrödinger (Ι) | biosc&med | Scoop.it
Πριν από λίγες μέρες, ακριβώς 126 χρόνια από την γέννηση του Erwin Schrödinger, η Google αφιέρωσε το λογότυπό της (doodle), στο παράδοξο της γάτας του Schrödinger. O Erwin Schrödinger μετά την διατ...

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