Magnified Image Magnets

False-colour scanning tunnelling micrograph (STM) of DNA. A sample of uncoated, double-stranded DNA was dissolved in a salt solution & deposited on graphite prior to being imaged in air by the STM. An STM image is formed by scanning a fine point just above the specimen surface & electronically recording the height of the point as it moves. This image shows a section of a double-stranded DNA molecule (a DNA duplex), with the coils of the helix appearing as the row of orange/yellow peaks in the centre of the image. The average distance between each peak is 3.5 nanometers. Magnification: x1,500,000 at 6x7cm size.

Human cell. Coloured transmission electron micro- graph (TEM) of a cross-section through a normal human cell. At above centre is the nucleus (large oval) containing genetic material in the form of DNA. Surrounding the nucleus is cell cytoplasm filled with endoplasmic reticulum. The endo- plasmic reticulum (ER) is a complex system of membranes which form a network of flattened cisternae (cavities). These function as reservoirs and channels for the storage and transport of substances through the cytoplasm. Here, the ER is coated in tiny particles known as ribosomes, responsible for the synthesis of cell proteins. Magnification: x10,000 at 6x4.5cm size.

Asbestosis: false-colour scanning electron micrograph (SEM) showing two macrophages impaled on an asbestos needle. Asbestosis is a lung disease (one of the pneumoconioses) caused by inhalation of asbestos fibres. Normally, foreign particles in the lungs are engulfed (phagocytosed) by the macrophages (mobile scavenger cells). Asbestos needles, however, are virtually indestructible and puncture the macrophages, destroying them and releasing their contents into the lung tissue. Asbestosis is linked with the development of mesotheliomas, cancers of the pleural membranes that surround the lungs. Magn: x2,000 at 6x7cm, x1,000 at 35mm size.

Eye pigment cell. Coloured scanning electron micrograph of a melanocyte cell with granules of pigment in the light-sensitive retina of the eye. The surface of this melanocyte cell (filling most of frame) has been removed revealing granules of melanin pigment (blue). Covering the cell are numerous finger-like processes called microvilli (purple). This melanocyte forms part of the pigmented epithelium, the outermost cell layer of the retina, beyond which is the highly pigmented choroid. The melanin pigment of this cell absorbs light rays passing through the retina. This prevents interference due to light reflection, assisting with vision. Magnification: unknown.

Adipose tissue. Coloured Scanning Electron Micro- graph (SEM) of fat cells making up adipose connective tissue. The rounded fat cells (brown, red) are called adipocytes. Connective tissue fibres (orange) have a supporting function for the fat cells. Almost the entire volume of each adipocyte is occupied by a single lipid droplet formed from triglycerides. Fat not used up in metabolic processes is housed in these cells. Adipose connective tissue forms a thick layer under the skin, around the buttocks, thighs and kidneys. It functions as an insulating layer and energy store. Magnification:x120 at 6x7cm size. Magnification: x140 at 4x5 inch size. Magnification: x60 at 35mm.

Bacteriophage. Coloured transmission electron micrograph of a T4 bacteriophage (orange) after injecting its viral DNA into the Escherichia coli bacterium (blue). Bacteriophages are viruses that infect bacteria; T4 is specific to E.coli. It is secured to the surface of the cell by spidery tail fibres. The tail, a contractile sheath, shortens to allow a syringe-like tube (below base plate of tail) to enter the cell membrane, emptying the DNA contents of the head into the bacterium. The capsid, a protein coat surrounding the DNA, stays outside. Phage' synthesis in the cell follows rapidly. Magnification: X65,000 at 6x7cm size. magnification: x220,000 at 10x8 size.

Iris of the eye. Coloured scanning electron micrograph (SEM) of the inner surfaces of the iris and adjoining structures in the human eye. At far right (blue) is the edge of the pupil, the hole that allows light into the eye. Coloured mauve is the iris which controls the size of the pupil and therefore how much light will enter. The band of folds down the centre (red) are the ciliary processes. These secrete fluids that nourish neighbouring parts of the eye. They are also the sites of attachment for the long, thin zonule filaments (yellow and green) which are responsible for suspending the lens (unseen). Magnification: unknown.

Rod cells. Coloured scanning electron micrograph (SEM) of a group of rod cells (blue/purple) in the retina of the eye. Rod cells are light sensitive cells which respond to dim light, and are mainly used for dark adapted vision. They cannot detect colours, which is why vision in low light conditions is limited to shades of grey. Colours are detected by cone cells (not seen). When light falls on the tip of a rod cell, a chemical reaction sends an electrical impulse to the optic nerve (not shown), which relays it to the visual cortex of the brain. Magnification unknown.

Cerebral cortex nerve cells. Light micrograph of a section through neurones (nerve cells, black) in the cerebral cortex of a human brain. Branching processes (dendrites) receive impulses from other nerve cells and pass them to the cell body (round, two at upper right). Each cell body also has an axon through which it relays nerve impulses to the dendrites of other neurones. Neurones allow information to be received, interpreted and relayed around the body. The grey matter of the cerebral cortex forms the outer layer of the brain that is responsible for conscious thought, memory and language. Magnification unknown.

Mitosis (image 4 of 6). Digital three-dimensional immunofluorescent light micrograph of a section through a mammalian cell during the anaphase stage of mitotic cell division. The two chromatids that form each chromosome (blue) are being pulled to opposite ends of the cell. The actin microfilam- ents (red) and tubulin microtubules (green) of the cytoskeleton maintain the cell's structure. The two centrosomes (pink dots, centre left & right) organize the microtubules that move the chromosom- es around the cell. Mitosis produces two identical daughter cells. This is a rat kangaroo kidney epi- thelial cell. Magnification: x500 at 6x7cm size. For a sequence of mitosis see images P673/052-057.

Human embryo. Coloured scanning electron micrograph (SEM) of a human embryo at the 16-cell stage on the tip of a pin. The ball of cells (yellow) of the embryo is known as a morula, a cluster of almost identical, rounded cells, each containing a central nucleus. This 16-cell embryo is about three days old. It is at the early stage of transformation from a single cell to a human composed of millions of cells. The cells multiply by repeated cleavage divisions (mitosis) and will form a hollow ball of cells (the blastocyst). Development of the blastocyst occurs before the embryo implants into the wall of the uterus (womb). Magnification: x130 at 6x7cm size. Magnification: x450 at 8x10 inch size.

Tiny fungivore snail shell under the microscope

Streamer chamber photo of an oxygen ion collision in the NA35 experiment at CERN, the European particle physics laboratory outside Geneva. The oxygen ion has collided at left with a nucleus of lead, producing a spray of particles that shoot out towards the right- hand side of the chamber. One particle is a low- energy electron which spirals inwards in the chamber's magnetic field, its track growing more dense as it loses energy.

Artificially coloured bubble chamber photo from CERN, the European particle physics laboratory outside Geneva. (1984)

Blood cells. Coloured scanning electron micrograph (SEM) of human blood showing red and white cells. Red blood cells (erythrocytes) have a characteristic biconcave-disc shape and are numerous. These large cells contain haemoglobin, a red pigment by which oxygen is transported around the body. They are more numerous than white blood cells, one of which is visible in this sample (white). White blood cells (leucocytes) are rounded cells with microvilli projections from the cell surface. Leucocytes play an important role in the immune response of the body. Magnification: x3,500 at 5x7cm size. x 7,750 at 6x4"

Streamer chamber photograph of 220 charged subatomic particles spilling out from the collision of a high-energy oxygen nucleus with a nucleus in a lead target. The picture was obtained by the NA35 experiment at CERN, the European particle physics laboratory outside Geneva. In addition to the 220 charged particles that leave a track in the streamer chamber, physicists estimated that a further 80 electrically neutral (& therefore invisible) particles were created in the collision. From a run in November 1986.

False colour transmission electron micrograph of the bullet-shaped rabies virus, a member of the Rhabdoviridae family. The virus has a protein coat or capsid (yellow), which is made up of helically arranged subunits called capsomeres. Within the coat is the genetic material, which in this virus is single-stranded RNA. The diffuse red surrounding the coat is the viral envelope, consisting of lipoprotein material. The rabies virus is transmitted to humans from an infected animal bite. Symptoms appear after an incubation period of 10 days to 1 year and include fever, breathing difficulties, muscle spasms, and hydrophobia. Magnification: x100,000 when printed at 10cm wide.

Photograph of a neutrino interaction event in the 15- foot bubble chamber at the Fermi National Accelerator Laboratory (Fermilab) near Chicago. The neutrino enters the bubble chamber at far right, but does not leave a track itself because it is electrically neutral. It interacts almost immediately with a proton in the liquid filling the bubble chamber, producing a spray of particles that travel towards the left, curving in the chamber's magnetic field. The V- shaped pairs of tracks in the lower half of the picture, which end in characteristic spiral curlicues, are electron- positron pairs produced from gamma-rays.

Blood clot. Coloured scanning electron micrograph (SEM) of red blood cells (erythrocytes) trapped in a fibrin mesh (brown). The production of fibrin is triggered by cells called platelets, activated when a blood vessel is damaged. The fibrin binds the various blood cells together, forming a solid structure called a blood clot. A blood clot is a normal response, preventing an excessive loss of blood. However, inappropriate clotting is a major cause of heart attacks and strokes.

Oxytocin. Polarised light micrograph of crystals of the female hormone oxytocin. In women this hormone is secreted naturally by the pituitary gland. It is also manufactured synthetically in the laboratory for use as a drug. Oxytocin causes contractions of the uterus during labour, and it also stimulates the flow of milk in women who are breast-feeding. As a drug it may be used to induce childbirth, or to help to expel the placenta. Oxytocin may be given in the form of a nasal spray to help increase milk flow while breast-feeding. Magnification: x50

Human embryo. Coloured scanning electron micrograph (SEM) of a human embryo at the 16-cell stage on the tip of a pin. The ball of cells (yellow) of the embryo is known as a morula, a cluster of almost identical, rounded cells, each containing a central nucleus. This 16-cell embryo is about three days old. It is at the early stage of transformation from a single cell to a human composed of millions of cells. The cells multiply by repeated cleavage divisions (mitosis) and will form a hollow ball of cells (the blastocyst). Development of the blastocyst occurs before the embryo implants into the wall of the uterus (womb). Magnification: x130 at 6x7cm size. Magnification: x450 at 8x10 inch size.

E. coli bacterium. Coloured scanning electron micrograph (SEM) of Escherichia coli bacterium. E. coli are Gram-negative rod-shaped bacteria that are part of the normal flora of the human gut. Some strains produce a toxin that causes severe diarrhoea and can be fatal, especially in the very young or elderly. The hair-like tendrils are the flagella, which the bacterium uses as propellers to move around. Magnification: x 25, 000 when printed at 10 centimetres high.

Fibroblast cells. Fluorescent light micrograph of two fibroblast cells, showing their nuclei (purple) and cytoskeleton. The cytoskeleton is made up of microtubules of the protein tubulin (yellow) and filaments of the protein actin (blue). The cytoskeleton supports the cell's structure, allows the cell to move and assists in the transport of organelles and vesicles within the cell. Fibroblasts are cells forming connective tissue, and are responsible for secreting connective tissue proteins such as collagen. Magnification: x980 when printed 10cm wide.

Bacteria infecting a macrophage. Coloured scanning electron micrograph (SEM) of Mycobacterium tuberculosis bacteria (purple) infecting a macrophage white blood cell. The macrophage, when activated, will engulf (phagocytose) the bacteria and destroy them as part of the body's immune response. M. tuberculosis causes the disease tuberculosis. It infects the lungs creating primary tubercles, nodular lesions of dead tissue and bacteria. The bacteria may enter the blood or lymph systems and spread to other organs of the body. Tuberculosis is spread by coughs and sneezes.

Kidney tubule. Coloured transmission electron micrograph (TEM) of a section through a proximal convoluted tubule in the kidney. The proximal convoluted tubules function to reabsorb water, glucose and other small molecules from the filtrate, producing a concentrated urine. The tubules consist of a lumen (interior, white) lined with cuboidal epithelial cells (green). These cells are covered in many finger-like projections known as microvilli, which serve to increase the cells' surface area for reabsorption. The cells' nuclei (brown), which contain the cells' genetic information, are also seen. The reabsorbed molecules move into the interstitial fluid of the kidney and are absorbed back into the blood. The liquid in the tubules passes to th...

Kidney stone crystals, scanning electron micrograph (SEM). Kidney stones are usually formed by the precipitation of the mineral salt calcium oxalate from the urine. The resulting hard, round stones (calculi) may cause severe pain, especially as they pass down the urinary tract. Large stones may need to be surgically removed or broken down using ultrasound therapy. Magnification: x2000 when printed 10cm wide.

Bubble chamber particle tracks. Coloured image showing a collection of tracks left by subatomic particles in a bubble chamber. A bubble chamber is a container filled with liquid hydrogen which is superheated - momentarily raised above its normal boiling point by a sudden drop in pressure in the container. Any charged particle passing through the liquid in this state leaves behind a trail of tiny bubbles as the liquid boils in its wake. These bubbles are seen as fine tracks, showing the characteristic paths of different types of particle. The paths are curved due to an intense applied magnetic field. The tightly-wound spiral tracks are due to electrons and positrons.

Subatomic particle tracks. Coloured bubble chamber photograph showing tracks left by subatomic particles from a particle accelerator at CERN, the European particle physics laboratory at Geneva. A bubble chamber is a container filled with liquid hydrogen which is superheated - momentarily raised above its normal boiling point by a sudden drop in pressure in the container. Any charged particle passing through the liquid in this state leaves behind a trail of tiny bubbles as the liquid boils in its wake. The bubbles are seen as fine tracks, which show the characteristic paths of different types of particle and which are curved due to an intense applied magnetic field.

Organ of Corti. Coloured scanning electron micrograph (SEM) of sensory hair cells from the organ of Corti, in the cochlea of the inner ear. These are the outer rows of hairs. These cells are surrounded by a fluid called the endolymph. As sound enters the ear it causes waves to form in the endolymph, which in turn cause these hairs to move. The movement is converted into an electrical signal, which is passed to the brain. Each V- shaped arrangement of hairs lies on the top of a single cell. Magnification: x8000 when printed 10cm wide.