In this image of a stained fruit fly ovary, the ovary is packed with immature eggs (with DNA stained blue). The cytoskeleton (in pink) is a collection of fibers that gives a cell shape and support. The signal-transmitting molecules like STAT (in yellow) are common to reproductive processes in humans. Researchers used this image to show molecular staining and high-resolution imaging techniques to students.

An Arachnoidiscus diatom with a diameter of 190µm. Diatoms are microscopic algae that have cell walls made of silica, which is the strongest known biological material relative to its density. In Arachnoidiscus, the cell wall is a radially symmetric pillbox-like shell composed of overlapping halves that contain intricate and delicate patterns. Sometimes, Arachnoidiscus is called “a wheel of glass.”

This image was taken with the orientation-independent differential interference contrast microscope.

How far and fast an infectious disease spreads across a community depends on many factors, including transportation. These U.S. maps, developed as part of an international study to simulate and analyze disease spread, chart daily commuting patterns. They show where commuters live (top) and where they travel for work (bottom). Green represents the fewest number of people whereas orange, brown, and white depict the most. Such information enables researchers and policymakers to visualize how an outbreak in one area can spread quickly across a geographic region.

Elastin is a fibrous protein in the extracellular matrix (ECM). It is abundant in artery walls like the one shown here. As its name indicates, elastin confers elasticity. Elastin fibers are at least five times stretchier than rubber bands of the same size. Tissues that expand, such as blood vessels and lungs, need to be both strong and elastic, so they contain both collagen (another ECM protein) and elastin. In this photo, the elastin-rich ECM is colored grayish brown and is most visible at the bottom of the photo. The curved red structures near the top of the image are red blood cells.

High-resolution time lapse of epithelial (skin) cell migration and wound healing. It shows an image taken every 13 seconds over the course of almost 14 minutes. The images were captured with quantitative orientation-independent differential interference contrast (DIC) microscope (left) and a conventional DIC microscope (right).

More information about the research that produced this video can be found in the Journal of Microscopy paper “An Orientation-Independent DIC Microscope Allows High Resolution Imaging of Epithelial Cell Migration and Wound Healing in a Cnidarian Model” by Malamy and Shribak.

Two fruit fly (Drosophila melanogaster) egg cells, one on each side of the central black line. The colorful swirls show the circular movement of cytoplasm—called ooplasmic streaming—that occurs in late egg cell development in wild-type (right) and mutant (left) oocytes. This image was captured using confocal microscopy.

More information on the research that produced this image can be found in the Journal of Cell Biology paper “Ooplasmic flow cooperates with transport and anchorage in Drosophila oocyte posterior determination” by Lu et al.

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.

This tropical scene, reminiscent of a postcard from Key West, is actually a petri dish containing an artistic arrangement of genetically engineered bacteria. The image showcases eight of the fluorescent proteins created in the laboratory of the late Roger Y. Tsien, a cell biologist at the University of California, San Diego. Tsien, along with Osamu Shimomura of the Marine Biology Laboratory and Martin Chalfie of Columbia University, share the 2008 Nobel Prize in chemistry for their work on green fluorescent protein-a naturally glowing molecule from jellyfish that has become a powerful tool for studying molecules inside living cells.

Bacteria engineered to act as genetic clocks flash in synchrony. Here, a "supernova" burst in a colony of coupled genetic clocks just after reaching critical cell density. Superimposed: A diagram from the notebook of Christiaan Huygens, who first characterized synchronized oscillators in the 17th century.

The green in this image highlights a protein called TonB, which is produced by many gram-negative bacteria, including those that cause typhoid fever, meningitis and dysentery. TonB lets bacteria take up iron from the host's body, which they need to survive. More information about the research behind this image can be found in a Biomedical Beat Blog posting from August 2013.

This normal human skin cell was treated with a growth factor that triggered the formation of specialized protein structures that enable the cell to move. We depend on cell movement for such basic functions as wound healing and launching an immune response.

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 that spontaneously emerged from scrambled frog eggs, with nuclei (blue) from frog sperm. Endoplasmic reticulum (red) and microtubules (green) are also visible. Image created using confocal microscopy.

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

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

These ripples of color represent the outer membrane of the nucleus inside an astrocyte, a star-shaped cell inside the brain. Some proteins (green) act as keys to unlock other proteins (red) that form gates to let small molecules in and out of the nucleus (blue). Visualizing these different cell components at the boundary of the astrocyte nucleus enables researchers to study the molecular and physiological basis of neurological disorders, such as hydrocephalus, a condition in which too much fluid accumulates in the brain, and scar formation in brain tissue leading to abnormal neuronal activity affecting learning and memory. Scientists have now identified a pathway may be common to many of these brain diseases and begun to further examine it to find ways to treat certain brain diseases and injuries.

Floral pattern emerging as two bacterial species, motile Acinetobacter baylyi and non-motile Escherichia coli (green), are grown together for 72 hours on 0.5% agar surface from a small inoculum in the center of a Petri dish.

See 6557 for a photo of this process at 24 hours on 0.75% agar surface.
See 6553 for a photo of this process at 48 hours on 1% agar surface.
See 6555 for another photo of this process at 48 hours on 1% agar surface.
See 6550 for a video of this process.

Cytoplasmic linker protein (CLIP)-170 is a microtubule plus-end-tracking protein that regulates microtubule dynamics and links microtubule ends to different intracellular structures. In this movie, the gene for CLIP-170 has been fused with green fluorescent protein (GFP). When the protein is expressed in cells, the activities can be monitored in real time. Here, you can see CLIP-170 streaming towards the edges of the cell.

Multicellular yeast called snowflake yeast that researchers created through many generations of directed evolution from unicellular yeast. Cells are connected to one another by their cell walls, shown in blue. Stained cytoplasm (green) and membranes (magenta) show that the individual cells remain separate. This image was captured using spinning disk confocal microscopy.

Related to images 6969 and 6971.

A colony of human embryonic stem cells (light blue) grows on fibroblasts (dark blue).

The 46 human chromosomes are shown in blue, with the telomeres appearing as white pinpoints. The DNA has already been copied, so each chromosome is actually made up of two identical lengths of DNA, each with its own two telomeres.

The cryo-EM structure of human adenovirus D26 (HAdV-D26) at near atomic resolution (3.7 Å), determined in collaboration with the NRAMM facility*. In difference to archetype HAdV-C5, the HAdV-D26 is a low seroprevalent viral vector, which is being used to generate Ebola virus vaccines.

A three-dimensional representation of the structure of E2, a key antigen protein involved with hepatitis C virus infection.

Individual cells are color-coded based on their identity and signaling activity using a protein circuit technology developed by the Coyle Lab. Just as a radio allows you to listen to an individual frequency, this technology allows researchers to tune into the specific “radio station” of each cell through genetically encoded proteins from a bacterial system called MinDE. The proteins generate an oscillating fluorescent signal that transmits information about cell shape, state, and identity that can be decoded using digital signal processing tools originally designed for telecommunications. The approach allows researchers to look at the dynamics of a single cell in the presence of many other cells.

Related to image 7021.

Proteins are long chains of amino acids. Each protein has a unique amino acid sequence. It is still a mystery how a protein folds into the proper shape based on its sequence. Scientists hope that one day they can "watch" this folding process for any given protein. The dream has been realized, at least partially, through the use of computer simulation.

T cells engulf and digest cells displaying markers (or antigens) for retroviruses, such as HIV.

Early on, this Arabidopsis plant embryo picks sides: While one end will form the shoot, the other will take root underground. Short pieces of RNA in the bottom half (blue) make sure that shoot-forming genes are expressed only in the embryo's top half (green), eventually allowing a seedling to emerge with stems and leaves. Like animals, plants follow a carefully orchestrated polarization plan and errors can lead to major developmental defects, such as shoots above and below ground. Because the complex gene networks that coordinate this development in plants and animals share important similarities, studying polarity in Arabidopsis--a model organism--could also help us better understand human development.

If a picture is worth a thousand words, what's a movie worth? For researchers studying cell migration, a "documentary" of fruit fly cells (bright green) traversing an egg chamber could answer longstanding questions about cell movement. See 2315 for video.

Detailed three-dimensional reconstruction of a tubular matrix in a thin section of the peripheral endoplasmic reticulum between the plasma membranes of the cell.
The endoplasmic reticulum (ER) is a continuous membrane that extends like a net from the envelope of the nucleus outward to the cell membrane. The ER plays several roles within the cell, such as in protein and lipid synthesis and transport of materials between organelles.
Shown here is a three-dimensional representation of the peripheral ER microtubules. Related to images 5855 and 5856

Multicellular yeast called snowflake yeast that researchers created through many generations of directed evolution from unicellular yeast. Here, the researchers visualized nuclei in orange to help them study changes in how the yeast cells divided. Cell walls are shown in blue. This image was captured using spinning disk confocal microscopy.

Related to images 6969 and 6970.

Serum albumin (SA) is the most abundant protein in the blood plasma of mammals. SA has a characteristic heart-shape structure and is a highly versatile protein. It helps maintain normal water levels in our tissues and carries almost half of all calcium ions in human blood. SA also transports some hormones, nutrients and metals throughout the bloodstream. Despite being very similar to our own SA, those from other animals can cause some mild allergies in people. Therefore, some scientists study SAs from humans and other mammals to learn more about what subtle structural or other differences cause immune responses in the body.

Related to entries 3744 and 3745.

A colorized scanning electron micrograph of bacteria. Scanning electron microscopes allow scientists to see the three-dimensional surface of their samples.

Body organs such as the liver and kidneys process chemicals and toxins. These "target" organs are susceptible to damage caused by these substances. See image 2496 for an unlabeled version of this illustration.

The new highly efficient parallelized DelPhi software was used to calculate the potential map distribution of an entire virus, the adeno-associated virus, which is made up of more than 484,000 atoms. Despite the relatively large dimension of this biological system, resulting in 815x815x815 mesh points, the parallelized DelPhi, utilizing 100 CPUs, completed the calculations within less than three minutes. Related to image 3374.

These images show frog cells in interphase. The cells are Xenopus XL177 cells, which are derived from tadpole epithelial cells. The microtubules are green and the chromosomes are blue. Related to 3442.

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.

Glial cells (stained green) in a fruit fly developing embryo have survived thanks to a signaling pathway initiated by neighboring nerve cells (stained red).

A protein called kinesin (blue) is in charge of moving cargo around inside cells and helping them divide. It's powered by biological fuel called ATP (bright yellow) as it scoots along tube-like cellular tracks called microtubules (gray).

Meiosis is the process whereby a cell reduces its chromosomes from diploid to haploid in creating eggs or sperm. See image 2545 for an unlabeled version of this illustration. See image 2544 for an unlabeled version of this illustration. Featured in The New Genetics.

This image shows a layer of retinal pigment epithelium cells derived from human embryonic stem cells, highlighting the nuclei (red) and cell surfaces (green). This kind of retinal cell is responsible for macular degeneration, the most common cause of blindness. Image and caption information courtesy of the California Institute for Regenerative Medicine. Related to image 3286

A cell nucleus (blue) surrounded by lipid droplets (yellow). Exogenously expressed, S-tagged UBXD8 (green) recruits endogenous p97/VCP (red) to the surface of lipid droplets in oleate-treated HeLa cells. Nucleus stained with DAPI.

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.

The world's smallest motor, ATP synthase, generates energy for the cell. See image 2517 for an unlabeled version of this illustration. Featured in The Chemistry of Health.

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).

The receptor is shown bound to an antagonist, eticlopride

Cell mopping up.

The human body keeps time with a master clock called the suprachiasmatic nucleus or SCN. Situated inside the brain, it's a tiny sliver of tissue about the size of a grain of rice, located behind the eyes. It sits quite close to the optic nerve, which controls vision, and this means that the SCN "clock" can keep track of day and night. The SCN helps control sleep by coordinating the actions of billions of miniature "clocks" throughout the body. These aren't actually clocks, but rather are ensembles of genes inside clusters of cells that switch on and off in a regular, 24-hour cycle in our physiological day.

Planarians are freshwater flatworms that have powerful abilities to regenerate their bodies, which would seem to make them natural model organisms in which to study stem cells. But until recently, scientists had not been able to efficiently find the genes that regulate the planarian stem cell system. In this image, a single stem cell has given rise to a colony of stem cells in a planarian. Proliferating cells are red, and differentiating cells are blue. Quantitatively measuring the size and ratios of these two cell types provides a powerful framework for studying the roles of stem cell regulatory genes in planarians.

Cdc42, a member of the Rho family of small guanosine triphosphatase (GTPase) proteins, regulates multiple cell functions, including motility, proliferation, apoptosis, and cell morphology. In order to fulfill these diverse roles, the timing and location of Cdc42 activation must be tightly controlled. Klaus Hahn and his research group use special dyes designed to report protein conformational changes and interactions, here in living neutrophil cells. Warmer colors in this image indicate higher levels of activation. Cdc42 looks to be activated at cell protrusions.

Related to images 2452, 2453, and 2454.

CCD-1 is an enzyme produced by the bacterium Clostridioides difficile that helps it resist antibiotics. Here, researchers crystallized bound pairs of CCD-1 molecules and molecules of the antibiotic cefotaxime. This enabled their structure to be studied using X-ray crystallography.

Related to images 6765, 6766, and 6767.

These images model the molecular structures of three enzymes with critical roles in the life cycle of the human immunodeficiency virus (HIV). At the top, reverse transcriptase (orange) creates a DNA copy (yellow) of the virus's RNA genome (blue). In the middle image, integrase (magenta) inserts this DNA copy in the DNA genome (green) of the infected cell. At the bottom, much later in the viral life cycle, protease (turquoise) chops up a chain of HIV structural protein (purple) to generate the building blocks for making new viruses. See these enzymes in action on PDB 101’s video A Molecular View of HIV Therapy.

NIGMS staff are located in the Natcher Building on the NIH campus.

Ecteinascidin 743 (ET-743, brand name Yondelis), was discovered and isolated from a sea squirt, Ecteinascidia turbinata, by NIGMS grantee Kenneth Rinehart at the University of Illinois. It was synthesized by NIGMS grantees E.J. Corey and later by Samuel Danishefsky. Multiple versions of this structure are available as entries 2790-2797.