Model of the mandelate racemase enzyme from Bacillus subtilis, a bacterium commonly found in soil.

Yeast cells with nuclei shown in green and contractile rings shown in magenta. Nuclei store DNA, and contractile rings help cells divide. This image was captured using wide-field microscopy with deconvolution.

Related to images 6791, 6793, 6794, 6797, 6798, and videos 6795 and 6796.

This illustration shows, in simplified terms, how the CRISPR-Cas9 system can be used as a gene-editing tool. The CRISPR system has two components joined together: a finely tuned targeting device (a small strand of RNA programmed to look for a specific DNA sequence) and a strong cutting device (an enzyme called Cas9 that can cut through a double strand of DNA). In this frame (2 of 4), the CRISPR machine locates the target DNA sequence once inserted into a cell.

For an explanation and overview of the CRISPR-Cas9 system, see the iBiology video, and find the full CRIPSR illustration here.

Scientists have long known that multicellular organisms use biological molecules produced by one cell and sensed by another to transmit messages that, for instance, guide proper development of organs and tissues. But it's been a puzzle as to how molecules dumped out into the fluid-filled spaces between cells can precisely home in on their targets. Using living tissue from fruit flies, a team led by Thomas Kornberg of the University of California, San Francisco, has shown that typical cells in animals can talk to each other via long, thin cell extensions called cytonemes (Latin for "cell threads") that may span the length of 50 or 100 cells. The point of contact between a cytoneme and its target cell acts as a communications bridge between the two cells.

Wound healing requires the action of stem cells. In mice that lack the Sept2/ARTS gene, stem cells involved in wound healing live longer and wounds heal faster and more thoroughly than in normal mice. This confocal microscopy image from a mouse lacking the Sept2/ARTS gene shows a tail wound in the process of healing. See more information in the article in Science.

Related to images 3498 and 3500.

This color-enhanced image is a scanning electron microscope image of retinal pigment epithelial (RPE) cells derived from human embryonic stem cells. The cells are remarkably similar to normal RPE cells, growing in a hexagonal shape in a single, well-defined layer. 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 3287.

Stereo triplet of a sea urchin embryo stained to reveal actin filaments (orange) and microtubules (blue). This image is part of a series of images: 1047, 1049, 1050, 1051 and 1052.

During cell division, spindle pole bodies (glowing dots) move toward the ends of yeast cells to separate copied genetic information. Contractile rings (glowing bands) form in cells’ middles and constrict to help them split. This time-lapse video was captured using wide-field microscopy with deconvolution.

Related to images 6791, 6792, 6793, 6794, 6797, 6798, and video 6795.

A cell in prometaphase during mitosis: The nuclear membrane breaks apart, and the spindle starts to interact with the chromosomes. 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.

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.

Yeast cells with the protein Fimbrin Fim1 shown in magenta. This protein plays a role in cell division. This image was captured using wide-field microscopy with deconvolution.

Related to images 6791, 6792, 6793, 6797, 6798, and videos 6795 and 6796.

Shortly after a pregnant woman gives birth, her breasts start to secrete milk. This process is triggered by hormonal and genetic cues, including the protein Elf5. Scientists discovered that Elf5 also has another job--it staves off cancer. Early in the development of breast cancer, human breast cells often lose Elf5 proteins. Cells without Elf5 change shape and spread readily--properties associated with metastasis. This image shows cells in the mouse mammary gland that are lacking Elf5, leading to the overproduction of other proteins (red) that increase the likelihood of metastasis.

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 have lined up in the middle of the dividing cell.

Related to images 1010, 1011, 1012, 1013, 1014, 1015, 1016, 1018, 1019, and 1021.

This scanning electron microscope (SEM) image shows podocytes--cells in the kidney that play a vital role in filtering waste from the bloodstream--from a patient with chronic kidney disease. This image first appeared in Princeton Journal Watch on October 4, 2013.

Lysosomes (yellow) and detyrosinated microtubules (light blue). Lysosomes are bubblelike organelles that take in molecules and use enzymes to break them down. Microtubules are strong, hollow fibers that provide structural support to cells. The researchers who took this image found that in epithelial cells, detyrosinated microtubules are a small subset of fibers, and they concentrate lysosomes around themselves. This image was captured using Stochastic Optical Reconstruction Microscopy (STORM).

Related to images 6890, 6891, and 6892.

A growing Vibrio cholerae (cholera) biofilm. Cholera bacteria form colonies called biofilms that enable them to resist antibiotic therapy within the body and other challenges to their growth.

Each slightly curved comma shape represents an individual bacterium from assembled confocal microscopy images. Different colors show each bacterium’s position in the biofilm in relation to the surface on which the film is growing.

This network map shows the overlap (green) between the long QT syndrome (yellow) and epilepsy (blue) protein-interaction neighborhoods located within the human interactome. Researchers have learned to integrate genetic, cellular and clinical information to find out why certain medicines can trigger fatal heart arrhythmias. Featured in Computing Life magazine.

Undifferentiated embryonic stem cells cease to exist a few days after conception. In this image, ES cells are shown to differentiate into sperm, muscle fiber, hair cells, nerve cells, and cone cells.

Model of a major secreted protein of unknown function, which is only found in mycobacteria, the class of bacteria that causes tuberculosis. Based on structural similarity, this protein may be involved in host-bacterial interactions.

The head of an axolotl—a type of salamander—that has been genetically modified so that its developing nervous system glows purple and its Schwann cell nuclei appear light blue. Schwann cells insulate and provide nutrients to peripheral nerve cells. Researchers often study axolotls for their extensive regenerative abilities. They can regrow tails, limbs, spinal cords, brains, and more. The researcher who took this image focuses on the role of the peripheral nervous system during limb regeneration.

This image was captured using a light sheet microscope.

Related to images 6928 and 6932.

Structure of a magnesium transporter protein from an antibiotic-resistant bacterium (Enterococcus faecalis) found in the human gut. Featured as one of the June 2007 Protein Sructure Initiative Structures of the Month.

These neurons are derived from mouse embryonic stem cells. Red shows cells making a protein called TH that is characteristic of the neurons that degenerate in Parkinson's disease. Green indicates a protein that's found in all neurons. Blue indicates the nuclei of all cells. Studying dopaminergic neurons can help researchers understand the origins of Parkinson's disease and could be used to screen potential new drugs. Image and caption information courtesy of the California Institute for Regenerative Medicine. Related to images 3270 and 3285.

Groups of Staphylococcus aureus bacteria (blue) attached to a microstructured titanium surface (green) that mimics an orthopedic implant used in joint replacement. The attachment of pre-formed groups of bacteria may lead to infections because the groups can tolerate antibiotics and evade the immune system. This image was captured using a scanning electron microscope.

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 6804 and video 6805.

On the left, a cross-section slice of a rat pancreas cell captured using cryo-electron tomography (cryo-ET). On the right, a 3D, color-coded version of the image highlighting cell structures. Visible features include microtubules (neon-green rods), ribosomes (small yellow circles), and vesicles (dark-blue circles). These features are surrounded by the partially visible endoplasmic reticulum (light blue). The black line at the bottom right of the left image represents 200 nm. Related to image 6607.

The Golgi complex, also called the Golgi apparatus or, simply, the Golgi. This organelle receives newly made proteins and lipids from the ER, puts the finishing touches on them, addresses them, and sends them to their final destinations.

Multicellular yeast called snowflake yeast that researchers created through many generations of directed evolution from unicellular yeast. Stained cell membranes (green) and cell walls (red) reveal the connections between cells. Younger cells take up more cell membrane stain, while older cells take up more cell wall stain, leading to the color differences seen here. This image was captured using spinning disk confocal microscopy.

Related to images 6970 and 6971.

Viruses have been the foes of animals and other organisms for time immemorial. For almost as long, they've stayed well hidden from view because they are so tiny (they aren't even cells, so scientists call the individual virus a "particle"). This image shows a molecular model of a particle of the Rous sarcoma virus (RSV), a virus that infects and sometimes causes cancer in chickens. In the background is a photo of red blood cells. The particle shown is "immature" (not yet capable of infecting new cells) because it has just budded from an infected chicken cell and entered the bird's bloodstream. The outer shell of the immature virus is made up of a regular assembly of large proteins (shown in red) that are linked together with short protein molecules called peptides (green).  This outer shell covers and protects the proteins (blue) that form the inner shell of the particle. But as you can see, the protective armor of the immature virus contains gaping holes. As the particle matures, the short peptides are removed and the large proteins rearrange, fusing together into a solid sphere capable of infecting new cells. While still immature, the particle is vulnerable to drugs that block its development. Knowing the structure of the immature particle may help scientists develop better medications against RSV and similar viruses in humans. Scientists used sophisticated computational tools to reconstruct the RSV atomic structure by crunching various data on the RSV proteins to simulate the entire structure of immature RSV.

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.

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.

This fluorescent microscope image shows human embryonic stem cells whose nuclei are stained green. Blue staining shows the surrounding supportive feeder cells. Image and caption information courtesy of the California Institute for Regenerative Medicine. See related image 3275.

These neurons were derived from human embryonic stem cells. The neural cell bodies with axonal projections are visible in red, and the nuclei in blue. Some of the neurons have become dopaminergic neurons (yellow), the type that degenerate in people with Parkinson's disease. Image and caption information courtesy of the California Institute for Regenerative Medicine. Related to images 3270 and 3271.

Pigment cells are cells that give skin its color. In fishes and amphibians, like frogs and salamanders, pigment cells are responsible for the characteristic skin patterns that help these organisms to blend into their surroundings or attract mates. The pigment cells are derived from neural crest cells, which are cells originating from the neural tube in the early embryo. This image shows pigment cells called xanthophores in the skin of zebrafish; the cells glow (autofluoresce) brightly under light giving the fish skin a shiny, lively appearance. Investigating pigment cell formation and migration in animals helps answer important fundamental questions about the factors that control pigmentation in the skin of animals, including humans. Related to images 5754, 5756, 5757 and 5758.

This illustration shows, in simplified terms, how the CRISPR-Cas9 system can be used as a gene-editing tool. This is the first frame in a series of four. The CRISPR system has two components joined together: a finely tuned targeting device (a small strand of RNA programmed to look for a specific DNA sequence) and a strong cutting device (an enzyme called Cas9 that can cut through a double strand of DNA).

For an explanation and overview of the CRISPR-Cas9 system, see the iBiology video, and find the full CRIPSR illustration here.

An adult Hawaiian bobtail squid, Euprymna scolopes, (~4 cm) surrounded by newly hatched juveniles (~2 mm) in a bowl of seawater.

Related to image 7011 and video 7012.

This slide shows the technologies that the Joint Center for Structural Genomics developed for going from gene to structure and how the technologies have been integrated into a high-throughput pipeline, including all of the steps from target selection, parallel expression, protein purification, automated crystallization trials, automated crystal screening, structure determination, validation, and publication.

Wound healing requires the action of stem cells. In mice that lack the Sept2/ARTS gene, stem cells involved in wound healing live longer and wounds heal faster and more thoroughly than in normal mice. This confocal microscopy image from a mouse lacking the Sept2/ARTS gene shows a tail wound in the process of healing. Cell nuclei are in blue. Red and orange mark hair follicle stem cells (hair follicle stem cells activate to cause hair regrowth, which indicates healing). See more information in the article in Science.

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.

These induced pluripotent stem cells (iPS cells) were derived from a woman's skin. Green and red indicate proteins found in reprogrammed cells but not in skin cells (TRA1-62 and NANOG). These cells can then develop into different cell types. Image and caption information courtesy of the California Institute for Regenerative Medicine. Related to image 3279.

Model of the enzyme aminopeptidase N from the human pathogen Neisseria meningitidis, which can cause meningitis epidemics. The structure provides insight on the active site of this important molecule.

Like tractor-trailers on a highway, small sacs called vesicles transport substances within cells. This image tracks the motion of vesicles in a living cell. The short red and yellow marks offer information on vesicle movement. The lines spanning the image show overall traffic trends. Typically, the sacs flow from the lower right (blue) to the upper left (red) corner of the picture. Such maps help researchers follow different kinds of cellular processes as they unfold.

A section of mouse colon with gut bacteria (center, in green) residing within a protective pocket. Understanding how microorganisms colonize the gut could help devise ways to correct for abnormal changes in bacterial communities that are associated with disorders like inflammatory bowel disease.

The receptor is shown bound to an inverse agonist, ZM241385.

This image captures Purkinje cells (red), one of the main types of nerve cell found in the brain. These cells have elaborate branching structures called dendrites that receive signals from other nerve cells.

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

NIGMS-funded researchers led by Roger Kornberg solved the structure of RNA polymerase II. This is the enzyme in mammalian cells that catalyzes the transcription of DNA into messenger RNA, the molecule that in turn dictates the order of amino acids in proteins. For his work on the mechanisms of mammalian transcription, Kornberg received the Nobel Prize in Chemistry in 2006.

Salk researchers captured the structure of a protein complex called an intasome (center) that lets viruses similar to HIV establish permanent infection in their hosts. The intasome hijacks host genomic material, DNA (white) and histones (beige), and irreversibly inserts viral DNA (blue). The image was created by Jamie Simon and Dmitry Lyumkis. Work that led to the 3D map was published in: Ballandras-Colas A, Brown M, Cook NJ, Dewdney TG, Demeler B, Cherepanov P, Lyumkis D, & Engelman AN. (2016). Cryo-EM reveals a novel octameric integrase structure for ?-retroviral intasome function. Nature, 530(7590), 358—361

Duplicated pair of chromosomes lined up and ready to cross over.

Along with blood vessels (red) and nerve cells (green), this mouse brain shows abnormal protein clumps known as plaques (blue). These plaques multiply in the brains of people with Alzheimer's disease and are associated with the memory impairment characteristic of the disease. Because mice have genomes nearly identical to our own, they are used to study both the genetic and environmental factors that trigger Alzheimer's disease. Experimental treatments are also tested in mice to identify the best potential therapies for human patients.

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

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

Some children are born with a mutation in a regulatory site on this enzyme that causes them to over-secrete insulin when they consume protein. We found that a compound from green tea (shown in the stick figure and by the yellow spheres on the enzyme) is able to block this hyperactivity when given to animals with this disorder.