Genes are often interrupted by stretches of DNA (introns, blue) that do not contain instructions for making a protein. The DNA segments that do contain protein-making instructions are known as exons (green). See image 2550 for an unlabeled version of this illustration. Featured in The New Genetics.

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.

Acetylsalicylate (bottom) is the aspirin of today. Adding a chemical tag called an acetyl group (shaded box, bottom) to a molecule derived from willow bark (salicylate, top) makes the molecule less acidic (and easier on the lining of the digestive tract), but still effective at relieving pain. See image 2529 for an unlabeled version of this illustration. Featured in Medicines By Design.

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.

Genes are often interrupted by stretches of DNA (introns, blue) that do not contain instructions for making a protein. The DNA segments that do contain protein-making instructions are known as exons (green). See image 2551 for a labeled version of this illustration. Featured in The New Genetics.

A genetic disorder of the nervous system, neurofibromatosis causes tumors to form on nerves throughout the body, including a type of tumor called an optic nerve glioma that can result in childhood blindness. The image was used to demonstrate the unique imaging capabilities of one of our newest (at the time) laser scanning microscopes and is of a wildtype (normal) mouse retina in the optic fiber layer. This layer is responsible for relaying information from the retina to the brain and was fluorescently stained to reveal the distribution of glial cells (green), DNA and RNA in the cell bodies of the retinal ganglion neurons (orange) and their optic nerve fibers (red), and actin in endothelial cells surrounding a prominent branching blood vessel (blue). By studying the microscopic structure of normal and diseased retina and optic nerves, we hope to better understand the altered biology of the tissues in these tumors with the prospects of developing therapeutic interventions.

Researchers used cryo-electron tomography (cryo-ET) to capture images of a rat pancreas cell that were then compiled and color-coded to produce a 3D reconstruction. Visible features include the folded sacs of the Golgi apparatus (copper), transport vesicles (medium-sized dark-blue circles), microtubules (neon-green rods), a mitochondria membrane (pink), ribosomes (small pale-yellow circles), endoplasmic reticulum (aqua), and lysosomes (large yellowish-green circles). See 6606 for a still image from the video.

The green spots in this mouse brain are cells labeled with Calling Cards, a technology that records molecular events in brain cells as they mature. Understanding these processes during healthy development can guide further research into what goes wrong in cases of neuropsychiatric disorders. Also fluorescently labeled in this video are neurons (red) and nuclei (blue). Calling Cards and its application are described in the Cell paper “Self-Reporting Transposons Enable Simultaneous Readout of Gene Expression and Transcription Factor Binding in Single Cells” by Moudgil et al.; and the Proceedings of the National Academy of Sciences paper “A viral toolkit for recording transcription factor–DNA interactions in live mouse tissues” by Cammack et al. This video was created for the NIH Director’s Blog post The Amazing Brain: Tracking Molecular Events with Calling Cards.

Related to image 6780.

Gene transcription is a process by which the genetic information encoded in DNA is transcribed into RNA. It's essential for all life and requires the activity of proteins, called transcription factors, that detect where in a DNA strand transcription should start. In eukaryotes (i.e., those that have a nucleus and mitochondria), a protein complex comprising 14 different proteins is responsible for sniffing out transcription start sites and starting the process. This complex, called TFIID, represents the core machinery to which an enzyme, named RNA polymerase, can bind to and read the DNA and transcribe it to RNA. Scientists have used cryo-electron microscopy (cryo-EM) to visualize the TFIID-RNA polymerase-DNA complex in unprecedented detail. In this illustration, TFIID (blue) contacts the DNA and recruits the RNA polymerase (gray) for gene transcription. The start of the transcribed gene is shown with a flash of light. To learn more about the research that has shed new light on gene transcription, see this news release from Berkeley Lab. Related to video 5730.

Illustration of a sperm, the male reproductive cell.

A light organ (~0.5 mm across) of a Hawaiian bobtail squid, Euprymna scolopes, stained blue. At the time of this image, the crypts within the tissues of only one side of the organ had been colonized by green-fluorescent protein-labeled Vibrio fischeri cells, which can be seen here in green. This image was taken using confocal fluorescence microscopy.

Related to images 7016, 7017, 7018, and 7019.

During cell division, cells physically divide after separating their genetic material to create two daughter cells that are genetically identical to the parent cell. This process is important so that new cells can grow and develop. In this image, a human fibroblast cell—a type of connective tissue cell that plays a key role in wound healing and tissue repair—is dividing into two daughter cells. A cell protein called actin appears gray, the myosin II (part of the family of motor proteins responsible for muscle contractions) appears green, and DNA appears magenta.

Luciferase-based imaging enables visualization and quantification of internal organs and transplanted cells in live adult zebrafish. In this image, a cardiac muscle-restricted promoter drives firefly luciferase expression. This is the lateral and overhead (Bottom) view.
For imagery of the overhead view go to 3557.
For imagery of the lateral view go to 3558.
For more information about the illumated area go to 3559.

A cropped image of a white poppy. View poppy uncropped here 3424.

A drug's life in the body. Medicines taken by mouth pass through the liver before they are absorbed into the bloodstream. Other forms of drug administration bypass the liver, entering the blood directly. See 2528 for a labeled version of this illustration. Featured in Medicines By Design.

Mitochondria are the powerhouses of the cells, generating the energy the cells need to do their tasks and to stay alive. Researchers have studied mitochondria for some time because when these cell organelles don't work as well as they should, several diseases develop. In this photograph of cow cells taken with a microscope, the mitochondria were stained in bright yellow to visualize them in the cell. The large blue dots are the cell nuclei and the gray web is the cytoskeleton of the cells.

A rendering of an activity biosensor image overlaid with a cell-centered frame of reference used for image analysis of signal transduction. This is an example of NIH-supported research on single-cell analysis. Related to 2798 , 2799, 2800, 2801 and 2803.

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.

Closeup of C. elegans, tiny roundworms, with a ribosomal protein glowing red and muscle fibers glowing green. Researchers used these worms to study a molecular pathway that affects aging. The ribosomal protein is involved in protein translation and may play a role in dietary restriction-induced longevity. Image created using confocal microscopy.
View single roundworm here 6581.
View group of roundworms here 6582.

Dynein (green) is a motor protein that “walks” along microtubules (red, part of the cytoskeleton) and carries its cargo along with it. This video was captured through fluorescence microscopy.

Fruit flies are a common model organism for basic medical research.

Circadian rhythms are physical, mental, and behavioral changes that follow a 24-hour cycle. Typical circadian rhythms lead to high energy during the middle of the day (10 a.m. to 1 p.m.) and an afternoon slump. At night, circadian rhythms cause the hormone melatonin to rise, making a person sleepy.

Learn more in NIGMS’ circadian rhythms featured topics page.

See 6612 for the Spanish version of this infographic.

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.

Mosquito larvae with genes edited by CRISPR swimming in water. 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 video optimized the gene-editing tool CRISPR 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 images 6769 and 6770.

This time-lapse video shows the emergence of a flower-like pattern in a mixture of two bacterial species, motile Acinetobacter baylyi and non-motile Escherichia coli (green), that are grown together for 24 hours on 0.75% 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 6556 for a photo of this process at 72 hours on 0.5% agar surface.

Multiphoton fluorescence image of cultured HeLa cells with a fluorescent protein targeted to the Golgi apparatus (orange), microtubules (green) and counterstained for DNA (cyan). Nikon RTS2000MP custom laser scanning microscope. See related images 3518, 3519, 3520, 3521.

The chemical structure of the morphine molecule

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.

A cell in metaphase during mitosis: The copied chromosomes align in the middle 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.

Structure of the bacterial antitoxin protein GhoS. GhoS inhibits the production of a bacterial toxin, GhoT, which can contribute to antibiotic resistance. GhoS is the first known bacterial antitoxin that works by cleaving the messenger RNA that carries the instructions for making the toxin. More information can be found in the paper: Wang X, Lord DM, Cheng HY, Osbourne DO, Hong SH, Sanchez-Torres V, Quiroga C, Zheng K, Herrmann T, Peti W, Benedik MJ, Page R, Wood TK. A new type V toxin-antitoxin system where mRNA for toxin GhoT is cleaved by antitoxin GhoS. Nat Chem Biol. 2012 Oct;8(10):855-61. Related to 3427.

Telophase during mitosis: Nuclear membranes form around each of the two sets of chromosomes, the chromosomes begin to spread out, and the spindle begins to break down. 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.

Recombinant proteins such as the prion protein shown here are often used to model how proteins misfold and sometimes polymerize in neurodegenerative disorders. This prion protein was expressed in E. coli, purified and fibrillized at pH 7. Image taken in 2004 for a research project by Roger Moore, Ph.D., at Rocky Mountain Laboratories that was published in 2007 in Biochemistry. This image was not used in the publication.

Like a building supported by a steel frame, a cell contains its own sturdy internal scaffolding made up of proteins, including microtubules. Researchers studying snapshots of microtubules have proposed a model for how these structural elements shorten and lengthen, allowing a cell to move, divide, or change shape. This picture shows an intermediate step in the model: Smaller building blocks called tubulins peel back from the microtubule in thin strips. Knowing the operations of the internal scaffolding will enhance our basic understanding of cellular processes.

Sketch of an egg cell.

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.

Crystals of bovine milk alpha-lactalbumin protein created for X-ray crystallography, which can reveal detailed, three-dimensional protein structures.

Vibrio fischeri cells (~ 2 mm), labeled with green fluorescent protein (GFP), passing through a very narrow bottleneck in the tissues (red) of the Hawaiian bobtail squid, Euprymna scolopes, on the way to the crypts where the symbiont population resides. This image was taken using a confocal fluorescence microscope.

Acetylsalicylate (bottom) is the aspirin of today. Adding a chemical tag called an acetyl group (shaded box, bottom) to a molecule derived from willow bark (salicylate, top) makes the molecule less acidic (and easier on the lining of the digestive tract), but still effective at relieving pain. See image 2530 for a labeled version of this illustration. Featured in Medicines By Design.

A typical animal cell cycle lasts roughly 24 hours, but depending on the type of cell, it can vary in length from less than 8 hours to more than a year. Most of the variability occurs in Gap1. Appears in the NIGMS booklet Inside the Cell.

PETase enzyme degrades polyester plastic (polyethylene terephthalate, or PET) into monohydroxyethyl terephthalate (MHET). Then, MHETase enzyme degrades MHET into its constituents ethylene glycol (EG) and terephthalic acid (TPA).

Find these in the RCSB Protein Data Bank: PET hydrolase (PDB entry 5XH3) and MHETase (PDB entry 6QGA).

A segment of siRNA, shown in red, guides a "slicer" protein called Argonaute (multi-colored twists and corkscrews) to the target RNA molecules.

Influenza A infects a host cell when hemagglutinin grips onto glycans on its surface. Neuraminidase, an enzyme that chews sugars, helps newly made virus particles detach so they can infect other cells. Related to 213. Featured in the March 2006, issue of Findings in "Viral Voyages."

The cerebellum of a mouse is shown here in cross-section. 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 higher magnification, see image 3371.

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

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.

This computer algorithm plots all feasible small carbon-based molecules as though they were cities on a map and identifies huge, unexplored spaces that may help fuel research into new drug therapies. Featured in the May 16, 2013 issue of Biomedical Beat.

Cultured hippocampal neurons grown on a substrate of glial cells (astrocytes). The glial cells form the pink/brown underlayment in this image. The tan threads are the neurons. The round tan balls are synapses, the points where neurons meet and communicate with each other. The cover slip underlying the cells is green. Neurons in culture can be used to study synaptic plasticity, activity-dependent protein turnover, and other topics in neuroscience.

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

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

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