Illuminating Intestines Many of the tissues in our body are constantly renewing, but none so fast as the lining of our gut. Each epithelial cell lining the human intestine lasts about a week. They start life in deep pits called crypts and, as they age, are pushed further up the steep sides of tiny projections called villi, which protrude into the intestinal space. At the tips of the villi, the cells die and detach. Scientists can now examine the lives of gut cells in more detail thanks to a clever labeling trick whereby stem cells in the crypts randomly switch on one of four fluorescent proteins (red, yellow, green or blue). Pictured is a crypt showing epithelial descendants each bearing the colour of its stem cell, making it easy to trace the origins of these short-lived cells. photographie de Hans Clevers Cell, 143(1), 134-144 source BPoD
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Illuminating Intestines

Many of the tissues in our body are constantly renewing, but none so fast as the lining of our gut. Each epithelial cell lining the human intestine lasts about a week. They start life in deep pits called crypts and, as they age, are pushed further up the steep sides of tiny projections called villi, which protrude into the intestinal space. At the tips of the villi, the cells die and detach. Scientists can now examine the lives of gut cells in more detail thanks to a clever labeling trick whereby stem cells in the crypts randomly switch on one of four fluorescent proteins (red, yellow, green or blue). Pictured is a crypt showing epithelial descendants each bearing the colour of its stem cell, making it easy to trace the origins of these short-lived cells.

photographie de Hans Clevers Cell, 143(1), 134-144

source BPoD

Mitochondrial Net Three-dimensional image of mitochondria (cyan blue) and cell nuclei (red) in the early embryo of the nematode worm Caenorhabditis elegans, obtained using the super-resolution OMX microscope. Mitochondria function as cellular power plants and produce the energy needed for most cellular functions. photographie de Ehsan Pourkarimi (Wellcome Trust Centre for Gene Regulation and Expression, College of Life Sciences)
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Mitochondrial Net

Three-dimensional image of mitochondria (cyan blue) and cell nuclei (red) in the early embryo of the nematode worm Caenorhabditis elegans, obtained using the super-resolution OMX microscope. Mitochondria function as cellular power plants and produce the energy needed for most cellular functions.

photographie de Ehsan Pourkarimi (Wellcome Trust Centre for Gene Regulation and Expression, College of Life Sciences)

Division cellulaire / Cell divisionThis striking, spiralling sequence was created using time-lapse photography to show the process of division – known as mitosis – of a cancer cell over a period of an hour. In the centre of the shot, the first stage of the process is captured, with the red DNA encircled by a near-perfectly round cell membrane. The DNA begins to duplicate, and to separate within the cyan enclosure. With the identical copies of DNA at opposite ends of the cell, gradually the membrane contracts. The subtle developments from one snapshot to the next follow the two daughter cells as they split away from one another, ready to undergo the same process themselves roughly 16 hours later photographie de Kuan-Chung Su, Cancer Research UK, London Research Institute, Wellcome Images
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Division cellulaire / Cell division

This striking, spiralling sequence was created using time-lapse photography to show the process of division – known as mitosis – of a cancer cell over a period of an hour. In the centre of the shot, the first stage of the process is captured, with the red DNA encircled by a near-perfectly round cell membrane. The DNA begins to duplicate, and to separate within the cyan enclosure. With the identical copies of DNA at opposite ends of the cell, gradually the membrane contracts. The subtle developments from one snapshot to the next follow the two daughter cells as they split away from one another, ready to undergo the same process themselves roughly 16 hours later


photographie de Kuan-Chung Su, Cancer Research UK, London Research Institute, Wellcome Images

Chromosomes High Voltage transmission electron micrograph of human female (HeLa) mitotic chromosomes from metaphase arrested cell swollen in hypotonic medium and recorded at 1 MeV. This image was taken with a specimen tilt of 45 degrees. Grouped with it is an image of the same area at 55 degrees tilt, providing an oblique stereo view of the chromosome. source : Cell Image Library
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Chromosomes

High Voltage transmission electron micrograph of human female (HeLa) mitotic chromosomes from metaphase arrested cell swollen in hypotonic medium and recorded at 1 MeV. This image was taken with a specimen tilt of 45 degrees. Grouped with it is an image of the same area at 55 degrees tilt, providing an oblique stereo view of the chromosome.

source : Cell Image Library

Dictyostelium discoideum Dictyostelium discoideum or slime mold, is an amoeba; a single-celled organism, which spends most of its life on a diet of soil bacteria. Faced with famine, it has the unusual ability to form a ‘social’ structure to escape starvation. Amoebas clump together to form a ‘slug’ (bottom, left) that moves towards light. When the slug stops the cell-collective forms a fruiting body (far right), in which some cells die causing their companions to distribute widely (sporulation), in search of a better place to live. Dictyostelium is also a useful model organism. Many aspects of cellular biology in scenarios of health, disease and development depend on the ability of individual cells to communicate with their neighbours like these amoebas do. Many slime mold genes have human counterparts, so this amoeba can be used to investigate genes and test drugs of potential benefit to human health. source : BoD 03/04/12 Copyright M.J. Grimson & R.L. BlantonBiological Sciences Electron Microscopy Laboratory, Texas Tech University.
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Dictyostelium discoideum

Dictyostelium discoideum or slime mold, is an amoeba; a single-celled organism, which spends most of its life on a diet of soil bacteria. Faced with famine, it has the unusual ability to form a ‘social’ structure to escape starvation. Amoebas clump together to form a ‘slug’ (bottom, left) that moves towards light. When the slug stops the cell-collective forms a fruiting body (far right), in which some cells die causing their companions to distribute widely (sporulation), in search of a better place to live. Dictyostelium is also a useful model organism. Many aspects of cellular biology in scenarios of health, disease and development depend on the ability of individual cells to communicate with their neighbours like these amoebas do. Many slime mold genes have human counterparts, so this amoeba can be used to investigate genes and test drugs of potential benefit to human health.

source : BoD 03/04/12

Copyright M.J. Grimson & R.L. Blanton
Biological Sciences Electron Microscopy Laboratory, Texas Tech University.