Cellularization of fruit fly embryos Reconstruction of fruit fly embryos undergoing cellularization. Cellularization is used as a model to understand the regulation of cell division. The investigation of differences between wildtype (top) and mutants like drop out (bottom) will help to unravel aberrant gene function in cancer and other diseases. photographie de Daniel Hain (Division of Cell and Developmental Biology, College of Life Sciences)
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Cellularization of fruit fly embryos

Reconstruction of fruit fly embryos undergoing cellularization. Cellularization is used as a model to understand the regulation of cell division. The investigation of differences between wildtype (top) and mutants like drop out (bottom) will help to unravel aberrant gene function in cancer and other diseases.

photographie de Daniel Hain (Division of Cell and Developmental Biology, College of Life Sciences)

Régulation génétique lors de l’embryogenèse Animals develop according to a programed pattern – they follow one line from head to tail, and another from back to belly. In fruit fly embryos this pattern of development is orchestrated by a protein called dorsal, which switches certain genes on and off. Dorsal levels are spread unevenly around the embryo’s girth. The amount determines which genes are expressed where, which in turn dictates the fate of new cells. This embryo cross section shows the system at work. Each colour represents a different gene. At the top, where there is least dorsal protein, a gene called dpp (stained yellow) is turned on. At the bottom, high concentrations of dorsal switch on another gene (red). So this fluorescent pinwheel helps scientists understand how the right sorts of cells end up in the right place. source BPoD Angelike StathopoulosCalifornia Institute of Technology, USAPublished in Developmental Cell
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Régulation génétique lors de l’embryogenèse

Animals develop according to a programed pattern – they follow one line from head to tail, and another from back to belly. In fruit fly embryos this pattern of development is orchestrated by a protein called dorsal, which switches certain genes on and off. Dorsal levels are spread unevenly around the embryo’s girth. The amount determines which genes are expressed where, which in turn dictates the fate of new cells. This embryo cross section shows the system at work. Each colour represents a different gene. At the top, where there is least dorsal protein, a gene called dpp (stained yellow) is turned on. At the bottom, high concentrations of dorsal switch on another gene (red). So this fluorescent pinwheel helps scientists understand how the right sorts of cells end up in the right place.

source BPoD

Published in Developmental Cell
Angelike Stathopoulos
California Institute of Technology, USA
Published in Developmental Cell
Neurosphère The term stem cell was first used in the 19th century to describe the Darwin-esque evolution of multicellular organisms over millions of years. Today the term is used to reflect the evolutionary-like moulding that transforms a naïve cell into a mature committed specialist in a matter of days. Stem cells respond to chemical signals in their immediate environment prompting them to mature or differentiate, into specialised cells across our bodies. Organs can avail of part-mature stem cells locally to repair damaged tissue. This ball of neural stem cells (a neurosphere, with its DNA stained blue) has received the chemical cue to differentiate into neurons. After 45 days, the newly-transformed neurons (stained red) branch out in all directions. One day soon stem cell therapy could help reverse the damage done by Parkinson’s or Alzheimer’s. source : BPOD, Image created by Dr Elizabeth HartfieldFirst published in the Oxford University Biochemical Society magazine, Phenotype Winning image of Oxford University Press sponsored competition Snapshot
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Neurosphère

The term stem cell was first used in the 19th century to describe the Darwin-esque evolution of multicellular organisms over millions of years. Today the term is used to reflect the evolutionary-like moulding that transforms a naïve cell into a mature committed specialist in a matter of days. Stem cells respond to chemical signals in their immediate environment prompting them to mature or differentiate, into specialised cells across our bodies. Organs can avail of part-mature stem cells locally to repair damaged tissue. This ball of neural stem cells (a neurosphere, with its DNA stained blue) has received the chemical cue to differentiate into neurons. After 45 days, the newly-transformed neurons (stained red) branch out in all directions. One day soon stem cell therapy could help reverse the damage done by Parkinson’s or Alzheimer’s.

source : BPOD,

Image created by Dr Elizabeth Hartfield
First published in the Oxford University Biochemical Society magazine, Phenotype
Winning image of Oxford University Press sponsored competition Snapshot
Embryon de poulet / Chicken embryoThe ethereal organism in the centre of this image is a newly fertilised chicken, captured just two days into its embryonic existence. The surrounding haven of blood vessels, known as a vasculature, acts as a tiny life support mechanism to the developing creature, which at this stage is roughly the size of a five pence piece. This network of veins and arteries connects the chicken to the rest of the egg, enabling the embryo to feed on the rich underlying yolk. The embryo already displays a tiny heart and brain. The trailing bottom half of the organism will become the chicken’s body on which its wings and legs will emerge Photographie de Vincent Pasque, University of Cambridge, Wellcome Images
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Embryon de poulet / Chicken embryo

The ethereal organism in the centre of this image is a newly fertilised chicken, captured just two days into its embryonic existence. The surrounding haven of blood vessels, known as a vasculature, acts as a tiny life support mechanism to the developing creature, which at this stage is roughly the size of a five pence piece. This network of veins and arteries connects the chicken to the rest of the egg, enabling the embryo to feed on the rich underlying yolk. The embryo already displays a tiny heart and brain. The trailing bottom half of the organism will become the chicken’s body on which its wings and legs will emerge

Photographie de Vincent Pasque, University of Cambridge, Wellcome Images

Tubes digestifs d’embryons de poulet, caille, poisson zèbre et souris The digestive tracts of chick E12 (from left), quail E12, zebra finch E13, and mouse E16,5 embryos are shown with the mesenteric tissue still attached. The top row shows the relative size of the eggs (or embryo, in the case of the mammal). Composite photo courtesy of Natasza Kurpios source : What’s behind the predictably loopy gut, Harvard Science 2011
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Tubes digestifs d’embryons de poulet, caille, poisson zèbre et souris

Embryogenèse du Cerveau antérieur de souris (9 jours post-fécondation) Anterior development during early mouse embryogenesis - a scanning electron micrograph of the frontal view of a normal mouse embryo at nine days post fertilization. Image Credit: Kenichiro Taniguchi and David Wotton (University of Virginia). source : PLoS Genetics February 2012
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Embryogenèse du Cerveau antérieur de souris (9 jours post-fécondation)

Anterior development during early mouse embryogenesis - a scanning electron micrograph of the frontal view of a normal mouse embryo at nine days post fertilization.

Image Credit: Kenichiro Taniguchi and David Wotton (University of Virginia).


source : PLoS Genetics February 2012


Tortue siamoise / Two-headed tortoise Une tortue des steppes à deux têtes et six pattes est exposée au musée des sciences naturelles à Kiev. “Ce n’est pas vraiment une tortue à deux têtes au sens strict du terme, mais plutôt deux tortues siamoises”, a expliqué Iouri Jouravliov, un zoologue de la société Ekzoland, qui a organisé l’exposition. L’animal, âgé de 5 ans a deux têtes, deux coeurs, quatre pattes avant, mais deux arrière et un seul intestin”.Les deux têtes ont des caractères différents même dans leurs préférences alimentaires. Celle à gauche, dominante et plus active, “préfère la nourriture verte, l’autre, des produits aux couleurs plus chaudes: carottes, fleurs de pissenlit”, a expliqué le zoologue. A two-headed Central Asian tortoise has gone on show at the natural science museum in Kiev where visitors will be able to observe the different eating habits of each head over the next two months. “Strictly speaking it isn’t a tortoise with two heads, but rather two conjoined tortoises,” Yuri Yuravliov, a zoologist, told AFP. “The female has two heads, two hearts, four front legs, but only two hind ones, and one intestine,” he explained. The five-year-old tortoise has a heart-shaped shell, about a dozen centimetres (4.7 inches) in width, according to an AFP journalist. The two heads are quite different, even in their feeding habits. The left one is more dominant and active, “prefers green food, while the other prefers more brightly-coloured food — carrots and dandelion flowers,” said Yuravliov. The tortoise, a species that can live 50 to 60 years, was kept from birth by a Ukrainian in his home, he said. “Animals with this type of pathology are only rarely born and don’t survive in natural condition.” A 5 year old steppe turtle with two heads and six paws is displayed as part of an exhibition at the Science History Museum in Kiev on Friday. The Ukrainian born reptile, on display at the museum, has a heart-shaped shell, two hearts but only one intestine, organisers said. source : Reuters
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Tortue siamoise / Two-headed tortoise

Une tortue des steppes à deux têtes et six pattes est exposée au musée des sciences naturelles à Kiev. “Ce n’est pas vraiment une tortue à deux têtes au sens strict du terme, mais plutôt deux tortues siamoises”, a expliqué Iouri Jouravliov, un zoologue de la société Ekzoland, qui a organisé l’exposition. L’animal, âgé de 5 ans a deux têtes, deux coeurs, quatre pattes avant, mais deux arrière et un seul intestin”.Les deux têtes ont des caractères différents même dans leurs préférences alimentaires. Celle à gauche, dominante et plus active, “préfère la nourriture verte, l’autre, des produits aux couleurs plus chaudes: carottes, fleurs de pissenlit”, a expliqué le zoologue.

A two-headed Central Asian tortoise has gone on show at the natural science museum in Kiev where visitors will be able to observe the different eating habits of each head over the next two months. “Strictly speaking it isn’t a tortoise with two heads, but rather two conjoined tortoises,” Yuri Yuravliov, a zoologist, told AFP. “The female has two heads, two hearts, four front legs, but only two hind ones, and one intestine,” he explained. The five-year-old tortoise has a heart-shaped shell, about a dozen centimetres (4.7 inches) in width, according to an AFP journalist. The two heads are quite different, even in their feeding habits. The left one is more dominant and active, “prefers green food, while the other prefers more brightly-coloured food — carrots and dandelion flowers,” said Yuravliov. The tortoise, a species that can live 50 to 60 years, was kept from birth by a Ukrainian in his home, he said. “Animals with this type of pathology are only rarely born and don’t survive in natural condition.”

A 5 year old steppe turtle with two heads and six paws is displayed as part of an exhibition at the Science History Museum in Kiev on Friday. The Ukrainian born reptile, on display at the museum, has a heart-shaped shell, two hearts but only one intestine, organisers said.

source : Reuters