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.

The beating of cilia on the outside of the Hawaiian bobtail squid’s light organ concentrates Vibrio fischeri cells (green) present in the seawater into aggregates near the pore-containing tissue (red). From there, the bacterial cells (~2 mm) swim to the pores and migrate through a bottleneck into the interior crypts where a population of symbionts grow and remain for the life of the host. This image was taken using confocal fluorescence microscopy.

Related to images 7016, 7017, 7018, and 7020.

A cell in anaphase during mitosis: Chromosomes separate into two genetically identical groups and move to opposite ends of the spindle. Mitosis is responsible for growth and development, as well as for replacing injured or worn out cells throughout the body. For simplicity, mitosis is illustrated here with only six chromosomes.

Ionic and covalent bonds hold molecules, like sodium chloride and chlorine gas, together. Hydrogen bonds among molecules, notably involving water, also play an important role in biology. See image 2519 for an unlabeled version of this illustration. Featured in The Chemistry of Health.

Cells in an early-stage fruit fly embryo, showing the DIAP1 protein (pink), an inhibitor of apoptosis.

The chemical structure of the morphine molecule

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

An image of Caenorhabditis elegans, a tiny roundworm, showing internal structures including the intestine, pharynx, and body wall muscle. C. elegans is one of the simplest organisms with a nervous system. Scientists use it to study nervous system development, among other things. This image was captured with a quantitative orientation-independent differential interference contrast (OI-DIC) microscope. The scale bar is 100 µm.

More information about the microscopy that produced this image can be found in the Journal of Microscopy paper by Malamy and Shribak.

These cells get their name from the hairlike structures that extend from them into the fluid-filled tube of the inner ear. When sound reaches the ear, the hairs bend and the cells convert this movement into signals that are relayed to the brain. When we pump up the music in our cars or join tens of thousands of cheering fans at a football stadium, the noise can make the hairs bend so far that they actually break, resulting in long-term hearing loss.

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

This is a magnified view of an Arabidopsis thaliana leaf a few days after being exposed to the pathogen Hyaloperonospora arabidopsidis. The plant from which this leaf was taken is genetically resistant to the pathogen. The spots in blue show areas of localized cell death where infection occurred, but it did not spread. Compare this response to that shown in Image 2782. Jeff Dangl has been funded by NIGMS to study the interactions between pathogens and hosts that allow or suppress infection.

Ribonucleic acid (RNA) has a sugar-phosphate backbone and the bases adenine (A), cytosine (C), guanine (G), and uracil (U). See image 2555 for a labeled version of this illustration. Featured in The New Genetics.

The cells shown here are fibroblasts, one of the most common cells in mammalian connective tissue. These particular cells were taken from a mouse embryo. Scientists used them to test the power of a new microscopy technique that offers vivid views of the inside of a cell. The DNA within the nucleus (blue), mitochondria (green), and actin filaments in the cellular skeleton (red) are clearly visible.

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 shows hundreds of human embryonic stem cells in various stages of differentiating into neurons. Some cells have become neurons (red), while others are still precursors of nerve cells (green). The yellow is an imaging artifact resulting when cells in both stages are on top of each other. Image and caption information courtesy of the California Institute for Regenerative Medicine.

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. Video created using confocal 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: 6587, 6588, 6589.

Cell division is an incredibly coordinated process. It not only ensures that the new cells formed during this event have a full set of chromosomes, but also that they are endowed with all the cellular materials, including proteins, lipids and small functional compartments called organelles, that are required for normal cell activity. This proper apportioning of essential cell ingredients helps each cell get off to a running start.

This image shows an electron microscopy (EM) thin section taken at 10,000x magnification of a dividing yeast cell over-expressing the protein ubiquitin, which is involved in protein degradation and recycling. The picture features mother and daughter endosome accumulations (small organelles with internal vesicles), a darkly stained vacuole and a dividing nucleus in close contact with a cadre of lipid droplets (unstained spherical bodies).  Other dynamic events are also visible,  such as spindle microtubules in the nucleus and endocytic pits at the plasma membrane.

These extensive details were revealed thanks to a preservation method involving high-pressure freezing, freeze-substitution and Lowicryl HM20 embedding.

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

The feeding tube, or pharynx, of a planarian worm with cilia shown in red and muscle fibers shown in green

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.

Model of the catalytic portion of an enzyme, receptor-type tyrosine-protein phosphatase from humans. The enzyme consists of two identical protein subunits, shown in blue and green. The groups made up of purple and red balls represent phosphate groups, chemical groups that can influence enzyme activity. This phosphatase removes phosphate groups from the enzyme tyrosine kinase, counteracting its effects.

These yeast cells were exposed to a glucose (sugar) shortage. This caused the cells to compartmentalize HMGCR (green)—an enzyme involved in making cholesterol—to a patch on the nuclear envelope next to the vacuole/lysosome (purple). This process enhanced HMGCR activity and helped the yeast adapt to the glucose shortage. Researchers hope that understanding how yeast regulate cholesterol could ultimately lead to new ways to treat high cholesterol in people. This image was captured using a fluorescence microscope.

This is a tomographic reconstruction of a mitochondrion from an insect flight muscle. Mitochondria are cellular compartments that are best known as the powerhouses that convert energy from the food into energy that runs a range of biological processes. Nearly all our cells have mitochondria.

Xenopus laevis, the African clawed frog, has long been used as a model organism for studying embryonic development. The frog embryo on the left lacks the developmental factor Sizzled. A normal embryo is shown on the right.

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

A computer model shows how the endoplasmic reticulum is close to and almost wraps around mitochondria in the cell. The endoplasmic reticulum is lime green and the mitochondria are yellow. This image relates to a July 27, 2009 article in Computing Life.

Moving protein or other molecules to specific cells to treat or examine them has been a major biological challenge. Scientists have now developed a technique for delivering chemicals to individual cells. The approach involves gold nanowires that, for example, can carry tumor-killing proteins. The advance was possible after researchers developed electric tweezers that could manipulate gold nanowires to help deliver drugs to single cells.

This movie shows the manipulation of the nanowires for drug delivery to a single cell. To learn more about this technique, see this post in the Computing Life series.

X-ray crystallography allows researchers to see structures too small to be seen by even the most powerful microscopes. To visualize the arrangement of atoms within molecules, researchers can use the diffraction patterns obtained by passing X-ray beams through crystals of the molecule. This is a common way for solving the structures of proteins. See image 2511 for an unlabeled version of this illustration. Featured in The Structures of Life.

The intense X-rays produced by synchrotrons such as the Advanced Photon Source are ideally suited for protein structure determination. Using synchrotron X-rays and advanced computers scientists can determine protein structures at a pace unheard of decades ago.

Hydra magnipapillata is an invertebrate animal used as a model organism to study developmental questions, for example the formation of the body axis.

Superresolution microscopy work on endoplasmic reticulum (ER) in the peripheral areas of the cell showing details of the structure and arrangement in a complex web of tubes.
The 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. The ER has a flexible structure to allow it to accomplish these tasks by changing shape as conditions in the cell change. Shown here an image created by super-resolution microscopy of the ER in the peripheral areas of the cell showing details of the structure and the arrangements in a complex web of tubes. Related to images 5856 and 5857.

The incredible complexity of a mammalian eye (in this case from a mouse) is captured here. Each color represents a different type of cell. In total, there are nearly 70 different cell types, including the retina's many rings and the peach-colored muscle cells clustered on the left.

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

The long, stringy DNA that makes up genes is spooled within chromosomes inside the nucleus of a cell. (Note that a gene would actually be a much longer stretch of DNA than what is shown here.) See image 2540 for a labeled version of this illustration. Featured in The New Genetics.

The extracellular matrix (ECM) is most prevalent in connective tissues but also is present between the stems (axons) of nerve cells, as shown here. Blue-colored nerve cell axons are surrounded by brown-colored, myelin-supplying Schwann cells, which act like insulation around an electrical wire to help speed the transmission of electric nerve impulses down the axon. The ECM is pale pink. The tiny brown spots within it are the collagen fibers that are part of the ECM.

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.

Related to images 1010, 1011, 1012, 1013, 1015, 1016, 1017, 1018, 1019, and 1021.

A crystal of porcine trypsin protein created for X-ray crystallography, which can reveal detailed, three-dimensional protein structures.

Drugs enter different layers of skin via intramuscular, subcutaneous, or transdermal delivery methods. See image 2532 for a labeled version of this illustration. Featured in Medicines By Design.

Disassembly of vasculature and reassembly after addition and then washout of 250 µM TBZ in kdr:GFP frogs. Related to images 3403 and 3404.

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.

A computer model of the cell membrane, where the plasma membrane is red, endoplasmic reticulum is yellow, and mitochondria are blue. This image relates to a July 27, 2009 article in Computing Life.

A fruit fly (Drosophila melanogaster) egg chamber with microtubules shown in green and actin filaments shown in red. Egg chambers are multicellular structures in fruit flies ovaries that each give rise to a single egg. Microtubules and actin filaments give the chambers structure and shape. This image was captured using a confocal microscope.

More information on the research that produced this image can be found in the Current Biology paper "Gatekeeper function for Short stop at the ring canals of the Drosophila ovary" by Lu et al.

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.

A cross section of the measles virus in which six proteins (enlarged on the outside of the virus) work together to infect cells. The measles virus is extremely infectious; 9 out of 10 people exposed will contract the disease. Fortunately, an effective vaccine protects against infection. Portions of the proteins that have not been determined are shown with dots.

Learn more about the six proteins on PDB 101’s Molecule of the Month: Measles Virus Proteins. Structures are available for the ordered regions of nucleoprotein and phosphoprotein (PDB entries 5E4V, 3ZDO, 1T6O), but the remaining regions are thought to form a flexible, random tangle. For a larger look at the measles virus, see 6995.

An anchor cell (red) pushes through the basement membrane (green) that surrounds it. Some cells are able to push through the tough basement barrier to carry out important tasks--and so can cancer cells, when they spread from one part of the body to another. No one has been able to recreate basement membranes in the lab and they're hard to study in humans, so Duke University researchers turned to the simple worm C. elegans. The researchers identified two molecules that help certain cells orient themselves toward and then punch through the worm's basement membrane. Studying these molecules and the genes that control them could deepen our understanding of cancer spread.

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.

Lab-made liposomes contract where Z rings have gathered together and the constriction forces are greatest (arrows). The top picture shows a liposome, and the bottom picture shows fluorescence from Z rings (arrows) inside the same liposome simultaneously.

Zika virus is shown in cross section at center left. On the outside, it includes envelope protein (red) and membrane protein (magenta) embedded in a lipid membrane (light purple). Inside, the RNA genome (yellow) is associated with capsid proteins (orange). The viruses are shown interacting with receptors on the cell surface (green) and are surrounded by blood plasma molecules at the top.

To become products, reactants must overcome an energy hill. See image 2525 for an unlabeled version of this illustration. Featured in The Chemistry of Health.

A study published in March 2012 used cryo-electron microscopy to determine the structure of the DNA replication origin recognition complex (ORC), a semi-circular, protein complex (yellow) that recognizes and binds DNA to start the replication process. The ORC appears to wrap around and bend approximately 70 base pairs of double stranded DNA (red and blue). Also shown is the protein Cdc6 (green), which is also involved in the initiation of DNA replication. Related to video 3307 that shows the structure from different angles. From a Brookhaven National Laboratory news release, "Study Reveals How Protein Machinery Binds and Wraps DNA to Start Replication."

A fruit fly ovary, shown here, contains as many as 20 eggs. Fruit flies are not merely tiny insects that buzz around overripe fruit--they are a venerable scientific tool. Research on the flies has shed light on many aspects of human biology, including biological rhythms, learning, memory and neurodegenerative diseases. Another reason fruit flies are so useful in a lab (and so successful in fruit bowls) is that they reproduce rapidly. About three generations can be studied in a single month. Related to image 3607.

This sculpture made of purple and clear glass beads depicts bacteriophage Phi174, a virus that infects bacteria. It rests on a surface that portrays an adaptive landscape, a conceptual visualization. The ridges represent the gene combinations associated with the greatest fitness levels of the virus, as measured by how quickly the virus can reproduce itself. Phi174 is an important model system for studies of viral evolution because its genome can readily be sequenced as it evolves under defined laboratory conditions.

Mosquito larvae with genes edited by CRISPR. This species of mosquito, Culex quinquefasciatus, can transmit West Nile virus, Japanese encephalitis virus, and avian malaria, among other diseases. The researchers who took this image developed a gene-editing toolkit for Culex quinquefasciatus that could ultimately help stop the mosquitoes from spreading pathogens. The work is described in the Nature Communications paper "Optimized CRISPR tools and site-directed transgenesis towards gene drive development in Culex quinquefasciatus mosquitoes" by Feng et al. Related to image 6769 and video 6771.