In the worm C. elegans, double-stranded RNA made in neurons can silence matching genes in a variety of cell types through the transport of RNA between cells. The head region of three worms that were genetically modified to express a fluorescent protein were imaged and the images were color-coded based on depth. The worm on the left lacks neuronal double-stranded RNA and thus every cell is fluorescent. In the middle worm, the expression of the fluorescent protein is silenced by neuronal double-stranded RNA and thus most cells are not fluorescent. The worm on the right lacks an enzyme that amplifies RNA for silencing. Surprisingly, the identities of the cells that depend on this enzyme for gene silencing are unpredictable. As a result, worms of identical genotype are nevertheless random mosaics for how the function of gene silencing is carried out. For more, see journal article and press release. Related to image 6534.

A light microscope image of a cell from the endosperm of an African globe lily (Scadoxus katherinae). This is one frame of a time-lapse sequence that shows cell division in action. The lily is considered a good organism for studying cell division because its chromosomes are much thicker and easier to see than human ones. Staining shows microtubules in red and chromosomes in blue. Here, condensed chromosomes are clearly visible and are starting to line up.

Related to images 1010, 1011, 1012, 1013, 1014, 1015, 1017, 1018, 1019, and 1021.

Collecting and transporting cellular waste and sorting it into recylable and nonrecylable pieces is a complex business in the cell. One key player in that process is the endosome, which helps collect, sort and transport worn-out or leftover proteins with the help of a protein assembly called the endosomal sorting complexes for transport (or ESCRT for short). These complexes help package proteins marked for breakdown into intralumenal vesicles, which, in turn, are enclosed in multivesicular bodies for transport to the places where the proteins are recycled or dumped. In this image, two multivesicular bodies (with yellow membranes) contain tiny intralumenal vesicles (with a diameter of only 25 nanometers; shown in red) adjacent to the cell's vacuole (in orange).

Scientists working with baker's yeast (Saccharomyces cerevisiae) study the budding inward of the limiting membrane (green lines on top of the yellow lines) into the intralumenal vesicles. This tomogram was shot with a Tecnai F-20 high-energy electron microscope, at 29,000x magnification, with a 0.7-nm pixel, ~4-nm resolution.

To learn more about endosomes, see the Biomedical Beat blog post The Cell’s Mailroom. Related to a microscopy photograph 5768 that was used to generate this illustration and a zoomed-in version 5767 of this illustration.

Each of the tiny colored specs in this image is a cell on the surface of a fish scale. To better understand how wounds heal, scientists have inserted genes that make cells brightly glow in different colors into the skin cells of zebrafish, a fish often used in laboratory research. The colors enable the researchers to track each individual cell, for example, as it moves to the location of a cut or scrape over the course of several days. These technicolor fish endowed with glowing skin cells dubbed "skinbow" provide important insight into how tissues recover and regenerate after an injury.

For more information on skinbow fish, see the Biomedical Beat blog post Visualizing Skin Regeneration in Real Time and a press release from Duke University highlighting this research. Related to image 3782.

The fly fatbody is a nutrient storage and mobilization organ akin to the mammalian liver. The engulfment receptor Draper (green) is located at the cell surface of fatbody cells. The cell nuclei are shown in blue.

The structure of the endothelium, the thin layer of cells that line our arteries and veins, is visible here. The endothelium is like a gatekeeper, controlling the movement of materials into and out of the bloodstream. Endothelial cells are held tightly together by specialized proteins that function like strong ropes (red) and others that act like cement (blue).

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

During development, a zebrafish embryo is transformed from a ball of cells into a recognizable body plan by sweeping convergence and extension cell movements. This process is called gastrulation. Each line in this video represents the movement of a single zebrafish embryo cell over the course of 3 hours. The video was created using time-lapse confocal microscopy. Related to image 6775.

To develop a system for studying cell motility in unnatrual conditions -- a microscope slide instead of the body -- Tom Roberts and Katsuya Shimabukuro at Florida State University disassembled and reconstituted the motility parts used by worm sperm cells.

Staphylococcus aureus bacteria (blue) on the porous coating of a femoral hip stem used in hip replacement surgery. The relatively rough surface of an implant is a favorable environment for bacteria to attach and grow. This can lead to the development of biofilms, which can cause infections. The researchers who took this image are working to understand where biofilms are likely to develop. This knowledge could support the prevention and treatment of infections. A scanning electron microscope was used to capture this image.

More information on the research that produced this image can be found in the Antibiotics paper "Free-floating aggregate and single-cell-initiated biofilms of Staphylococcus aureus" by Gupta et al.

Related to image 6803 and video 6805.

This image shows an osteosarcoma cell with DNA in blue, energy factories (mitochondria) in yellow, and actin filaments—part of the cellular skeleton—in purple. One of the few cancers that originate in the bones, osteosarcoma is rare, with about a thousand new cases diagnosed each year in the United States.

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

A biofilm is a highly organized community of microorganisms that develops naturally on certain surfaces. These communities are common in natural environments and generally do not pose any danger to humans. Many microbes in biofilms have a positive impact on the planet and our societies. Biofilms can be helpful in treatment of wastewater, for example. This dime-sized biofilm, however, was formed by the opportunistic pathogen Pseudomonas aeruginosa. Under some conditions, this bacterium can infect wounds that are caused by severe burns. The bacterial cells release a variety of materials to form an extracellular matrix, which is stained red in this photograph. The matrix holds the biofilm together and protects the bacteria from antibiotics and the immune system.

This image of human red blood cells was obtained with the help of a scanning electron microscope, an instrument that uses a finely focused electron beam to yield detailed images of the surface of a sample.

This image is a computer-generated model of the approximately 4.2 million atoms of the HIV capsid, the shell that contains the virus' genetic material. Scientists determined the exact structure of the capsid and the proteins that it's made of using a variety of imaging techniques and analyses. They then entered these data into a supercomputer that produced the atomic-level image of the capsid. This structural information could be used for developing drugs that target the capsid, possibly leading to more effective therapies. Related to image 6601.

Trypanosoma brucei is a single-cell parasite that causes sleeping sickness in humans. Scientists have been studying trypanosomes for some time because of their negative effects on human and also animal health, especially in sub-Saharan Africa. Moreover, because these organisms evolved on a separate path from those of animals and plants more than a billion years ago, researchers study trypanosomes to find out what traits they may harbor that are common to or different from those of other eukaryotes (i.e., those organisms having a nucleus and mitochondria). This image shows the T. brucei cell membrane in red, the DNA in the nucleus and kinetoplast (a structure unique to protozoans, including trypanosomes, which contains mitochondrial DNA) in blue and nuclear pore complexes (which allow molecules to pass into or out of the nucleus) in green. Scientists have found that the trypanosome nuclear pore complex has a unique mechanism by which it attaches to the nuclear envelope. In addition, the trypanosome nuclear pore complex differs from those of other eukaryotes because its components have a near-complete symmetry, and it lacks almost all of the proteins that in other eukaryotes studied so far are required to assemble the pore.

The body uses a variety of ion channels to transport small molecules across cell membranes.

Novel biosensor system maps the timing and location of Rac protein activation in a living mouse embryo fibroblast.

The worm Caenorhabditis elegans is a popular laboratory animal because its small size and fairly simple body make it easy to study. Scientists use this small worm to answer many research questions in developmental biology, neurobiology, and genetics. This image, which was taken with transmission electron microscopy (TEM), shows a cross-section through C. elegans, revealing various internal structures labeled in the image. You can find a high-resolution image without the annotations at image 5759.

The image is from a figure in an article published in the journal eLife.

Amid a network of blood vessels and star-shaped support cells, neurons in the brain signal each other. The mists of color show the flow of important molecules like glucose and oxygen. This image is a snapshot from a 52-second simulation created by an animation artist. Such visualizations make biological processes more accessible and easier to understand.

Stained glomeruli in the kidney. The kidney is an essential organ responsible for disposing wastes from the body and for maintaining healthy ion levels in the blood. It works like a purifier by pulling break-down products of metabolism, such as urea and ammonium, from the bloodstream for excretion in urine. The glomerulus is a structure that helps filter the waste compounds from the blood. It consists of a network of capillaries enclosed within a Bowman's capsule of a nephron, which is the structure in which ions exit or re-enter the blood in the kidney.

Cell-like compartments that spontaneously emerged from scrambled frog eggs. Endoplasmic reticulum (red) and microtubules (green) are visible. Image created using epifluorescence microscopy.

For more photos of cell-like compartments from frog eggs view: 6584, 6585, 6591, 6592, and 6593.

For videos of cell-like compartments from frog eggs view: 6587, 6588, 6589, and 6590.

Human embryonic stem cells differentiated into dopaminergic neurons, the type that degenerate in Parkinson's disease. Image courtesy of the California Institute for Regenerative Medicine. Related to images 3271 and 3285.

Fat tissue from the abdomen of a genetically mosaic adult fruit fly. Genetic mosaicism means that the fly has cells with different genotypes even though it formed from a single zygote. This specific mosaicism results in accumulation of a critical fly adipokine (blue-green) within the fat tissue cells that have reduced expression a key nutrient sensing gene (in left panel). The dotted line shows the cells lacking the gene that is present and functioning in the rest of the cells. Nuclei are labelled in magenta. This image was captured using a confocal microscope and shows a maximum intensity projection of many slices.

Related to images 6982, 6984, and 6985.

This fused chromosome has two functional centromeres, shown as two sets of red and green dots. Centromeres are DNA/protein complexes that are key to splitting the chromosomes evenly during cell division. When dicentric chromosomes like this one are formed in a person, fertility problems or other difficulties may arise. Normal chromosomes carrying a single centromere (one set of red and green dots) are also visible in this image.

Yeast cells with endocytic actin patches (green). These patches help cells take in outside material. When a cell is in interphase, patches concentrate at its ends. During later stages of cell division, patches move to where the cell splits. This image was captured using wide-field microscopy with deconvolution.

Related to images 6791, 6792, 6794, 6797, 6798, and videos 6795 and 6796.

Here, bubonic plague bacteria (yellow) are shown in the digestive system of a rat flea (purple). The bubonic plague killed a third of Europeans in the mid-14th century. Today, it is still active in Africa, Asia, and the Americas, with as many as 2,000 people infected worldwide each year. If caught early, bubonic plague can be treated with antibiotics.

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

The glial cells (black dots) and nerve cells (brown bands) in this developing fruit fly nerve cord formed normally despite the absence of the SPITZ protein, which blocks their impending suicide. The HID protein, which triggers suicide, is also lacking in this embryo.

Cross section of human skeletal muscle. Image taken with a confocal fluorescent light microscope.

3D image of Caulobacter bacterium with various components highlighted: cell membranes (red and blue), protein shell (green), protein factories known as ribosomes (yellow), and storage granules (orange).

To better understand cell movements in developing embryos, researchers isolated cells from early zebrafish embryos and grew them as clusters. Provided with the right signals, the clusters replicated some cell movements seen in intact embryos. Each line in this image depicts the movement of a single cell. The image was created using time-lapse confocal microscopy. Related to video 6776.

Speckle microscopy analysis of actin cytoskeleton force. This is an example of NIH-supported research on single-cell analysis. Images in related series; Related to 2799, 2800, 2801, 2802 and 2803.

Bean-shaped mitochondria are cells' power plants. These organelles have their own DNA and replicate independently. The highly folded inner membranes are the site of energy generation.

A mouse liver glows after being tagged with specially designed infrared-fluorescent protein (IFP). Since its discovery in 1962, green fluorescent protein (GFP) has become an invaluable resource in biomedical imaging. But because of its short wavelength, the light that makes GFP glow doesn't penetrate far in whole animals. So University of California, San Diego cell biologist Roger Tsien--who shared the 2008 Nobel Prize in chemistry for groundbreaking work with GFP--made infrared-fluorescent proteins (IFPs) that shine under longer-wavelength light, allowing whole-body imaging in small animals.

Proteins in the neural tissues of this zebrafish embryo direct cells to line up and form the neural tube, which will become the spinal cord and brain. Studies of zebrafish embryonic development may help pinpoint the underlying cause of common neural tube defects--such as spina bifida--which occur in about 1 in 1,000 newborn children.

Video of high-resolution confocal images depicting vimentin immunofluorescence (green) and nuclei (blue) at the edge of a quail embryo yolk. These images were obtained as part of a study to understand cell migration in embryos. An NIGMS grant to Professor Garcia was used to purchase the confocal microscope that collected these images. Related to images 2807 and 2808.

In plants, as in animals, stem cells can transform into a variety of different cell types. The stem cells at the growing tip of this Arabidopsis plant will soon become flowers. Arabidopsis is frequently studied by cellular and molecular biologists because it grows rapidly (its entire life cycle is only 6 weeks), produces lots of seeds, and has a genome that is easy to manipulate.

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

This image captures the spiral-shaped ovary of an anglerfish in cross-section. Once matured, these eggs will be released in a gelatinous, floating mass. For some species of anglerfish, this egg mass can be up to 3 feet long and include nearly 200,000 eggs.

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

Cell-like compartments spontaneously emerge from scrambled frog eggs, with nuclei (blue) from frog sperm. Endoplasmic reticulum (red) and microtubules (green) are also visible. Video created using epifluorescence microscopy.

For more photos of cell-like compartments from frog eggs view: 6584, 6585, 6586, 6591, 6592, and 6593.

For videos of cell-like compartments from frog eggs view: 6588, 6589, and 6590.

Originally from the waters of India, Nepal, and neighboring countries, zebrafish can now be found swimming in science labs (and home aquariums) throughout the world. This fish is a favorite study subject for scientists interested in how genes guide the early stages of prenatal development (including the developing fin shown here) and in the effects of environmental contamination on embryos.

In this image, green fluorescent protein (GFP) is expressed where the gene sox9b is expressed. Collagen (red) marks the fin rays, and DNA, stained with a dye called DAPI, is in blue. sox9b plays many important roles during development, including the building of the heart and brain, and is also necessary for skeletal development. At the University of Wisconsin, researchers have found that exposure to contaminants that bind the aryl-hydrocarbon receptor results in the downregulation of sox9b. Loss of sox9b severely disrupts development in zebrafish and causes a life-threatening disorder called campomelic dysplasia (CD) in humans. CD is characterized by cardiovascular, neural, and skeletal defects. By studying the roles of genes such as sox9b in zebrafish, scientists hope to better understand normal development in humans as well as how to treat developmental disorders and diseases.

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

Hepatocytes, like the one shown here, are the most abundant type of cell in the human liver. They play an important role in building proteins; producing bile, a liquid that aids in digesting fats; and chemically processing molecules found normally in the body, like hormones, as well as foreign substances like medicines and alcohol.

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

The cerebellum is the brain's locomotion control center. Every time you shoot a basketball, tie your shoe or chop an onion, your cerebellum fires into action. Found at the base of your brain, the cerebellum is a single layer of tissue with deep folds like an accordion. People with damage to this region of the brain often have difficulty with balance, coordination and fine motor skills. For a lower magnification, see image 3639.

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

Cross-section of skin anatomy shows layers and different tissue types.

Of the three muscle fibers shown here, the one on the right and the one on the left are normal. The middle fiber is deficient a large protein called nebulin (blue). Nebulin plays a number of roles in the structure and function of muscles, and its absence is associated with certain neuromuscular disorders.

This image was part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

Scanning electron micrograph of just-divided HeLa cells. Zeiss Merlin HR-SEM. See related images 3519, 3520, 3521, 3522.

Multiphoton fluorescence image of HeLa cells with cytoskeletal microtubules (magenta) and DNA (cyan). Nikon RTS2000MP custom laser scanning microscope. See related images 3518, 3519, 3521, 3522.

This image of the human brain uses colors and shapes to show neurological differences between two people. The blurred front portion of the brain, associated with complex thought, varies most between the individuals. The blue ovals mark areas of basic function that vary relatively little. Visualizations like this one are part of a project to map complex and dynamic information about the human brain, including genes, enzymes, disease states, and anatomy. The brain maps represent collaborations between neuroscientists and experts in math, statistics, computer science, bioinformatics, imaging, and nanotechnology.

Cells progress through a cycle that consists of phases for growth (blue, green, yellow) and division (red). Cells become quiescent when they exit this cycle (purple). See image 2499 for a labeled version of this illustration.

Mitosis creates cells, and apoptosis kills them. The processes often work together to keep us healthy.

Sensory organs have cells equipped for detecting signals from the environment, such as odors. Receptors in the membranes of nerve cells in the nose bind to odor molecules, triggering a cascade of chemical reactions tranferred by G proteins into the cytoplasm.

Thin, hair-like biological structures called cilia are tiny but mighty. Each one, made up of more than 600 different proteins, works together with hundreds of others in a tightly-packed layer to move like a crowd at a ball game doing "the wave." Their synchronized motion helps sweep mucus from the lungs and usher eggs from the ovaries into the uterus. By controlling how fluid flows around an embryo, cilia also help ensure that organs like the heart develop on the correct side of your body.