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 3428.

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, 6592.

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

The receptor is shown bound to an antagonist, compound-24

Damage to each person's genome, often called the "Book of Life," accumulates with time. Such DNA mutations arise from errors in the DNA copying process, as well as from external sources, such as sunlight and cigarette smoke. DNA mutations are known to cause cancer and also may contribute to cellular aging.

At the root tips of the mustard plant Arabidopsis thaliana (red), two proteins work together to control the uptake of water and nutrients. When the cell division-promoting protein called Short-root moves from the center of the tip outward, it triggers the production of another protein (green) that confines Short-root to the nutrient-filtering endodermis. The mechanism sheds light on how genes and proteins interact in a model organism and also could inform the engineering of plants.

Actin is an essential protein in a cell's skeleton (cytoskeleton). It forms a dense network of thin filaments in the cell. Here, researchers have used a technique called stochastic optical reconstruction microscopy (STORM) to visualize the actin network in a cell in three dimensions. The actin strands were labeled with a dye called Alexa Fluor 647-phalloidin.  This image appears in a study published by Nature Methods, which reports how researchers use STORM to visualize the cytoskeleton.

The marine bacterium Vibrio harveyi glows when near its kind. This luminescence, which results from biochemical reactions, is part of the chemical communication used by the organisms to assess their own population size and distinguish themselves from other types of bacteria. But V. harveyi only light up when part of a large group. This communication, called quorum sensing, speaks for itself here on a lab dish, where more densely packed areas of the bacteria show up blue. Other types of bacteria use quorum sensing to release toxins, trigger disease, and evade the immune system.

X-ray co-crystal structure of Src kinase bound to a DNA-templated macrocycle inhibitor. Related to 3414, 3415, 3416, 3417, 3418, and 3419.

The membrane that surrounds a cell is made up of proteins and lipids. Depending on the membrane's location and role in the body, lipids can make up anywhere from 20 to 80 percent of the membrane, with the remainder being proteins. Cholesterol (green), which is not found in plant cells, is a type of lipid that helps stiffen the membrane.

By attaching fluorescent proteins to the genetic circuit responsible for B. subtilis's stress response, researchers can observe the cells' pulses as green flashes. In response to a stressful environment like one lacking food, B. subtilis activates a large set of genes that help it respond to the hardship. Instead of leaving those genes on as previously thought, researchers discovered that the bacteria flip the genes on and off, increasing the frequency of these pulses with increasing stress. See entry 3254 for the related video.

Nucleotides in DNA are copied into RNA, where they are read three at a time to encode the amino acids in a protein. Many parts of a protein fold as the amino acids are strung together.

See image 2510 for a labeled version of this illustration.

Featured in The Structures of Life.

The center cluster of cells, colored blue, shows a colony of human embryonic stem cells. These cells, which arise at the earliest stages of development, are capable of differentiating into any of the 220 types of cells in the human body and can provide access to cells for basic research and potential therapies. This image is from the lab of the University of Wisconsin-Madison's James Thomson.

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.

A combination of protein structures determined experimentally and computationally shows us the complete metabolic network of a heat-loving bacterium.

Ribosomes are complex machines made up of more than 50 proteins and three or four strands of genetic material called ribosomal RNA (rRNA). The busy cellular machines make proteins, which are critical to almost every structure and function in the cell. To do so, they read protein-building instructions, which come as strands of messenger RNA. Ribosomes are found in all forms of cellular life—people, plants, animals, even bacteria. This illustration of a bacterial ribosome was produced using detailed information about the position of every atom in the complex. Several antibiotic medicines work by disrupting bacterial ribosomes but leaving human ribosomes alone. Scientists are carefully comparing human and bacterial ribosomes to spot differences between the two. Structures that are present only in the bacterial version could serve as targets for new antibiotic medications.

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.

The image visualizes a part of the yeast molecular interaction network. The lines in the network represent connections among genes (shown as little dots) and different-colored networks indicate subnetworks, for instance, those in specific locations or pathways in the cell. Researchers use gene or protein expression data to build these networks; the network shown here was visualized with a program called Cytoscape. By following changes in the architectures of these networks in response to altered environmental conditions, scientists can home in on those genes that become central "hubs" (highly connected genes), for example, when a cell encounters stress. They can then further investigate the precise role of these genes to uncover how a cell's molecular machinery deals with stress or other factors. Related to images 3730 and 3732.

Dengue virus is a mosquito-borne illness that infects millions of people in the tropics and subtropics each year. Like many viruses, dengue is enclosed by a protective membrane. The proteins that span this membrane play an important role in the life cycle of the virus. Scientists used cryo-EM to determine the structure of a dengue virus at a 3.5-angstrom resolution to reveal how the membrane proteins undergo major structural changes as the virus matures and infects a host. For more on cryo-EM see the blog post Cryo-Electron Microscopy Reveals Molecules in Ever Greater Detail. Related to image 3756.

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.

A number of environmental factors cause DNA mutations that can lead to cancer: toxins in cigarette smoke, sunlight and other radiation, and some viruses.

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, 1048, 1050, 1051 and 1052.

A large number of proteins interact with the hormone insulin as it is produced in and secreted from the beta cells of the pancreas. In this image, the interactions of TMEM24 protein (green) and insulin (red) in pancreatic beta cells are shown in yellow. More information about the research behind this image can be found in a Biomedical Beat Blog posting from November 2013.

This image shows the structure of the CYP17A1 enzyme (ribbons colored from blue N-terminus to red C-terminus), with the associated heme colored black. The prostate cancer drug abiraterone is colored gray. Cytochrome P450 enzymes bind to and metabolize a variety of chemicals, including drugs. Cytochrome P450 17A1 also helps create steroid hormones. Emily Scott's lab is studying how CYP17A1 could be selectively inhibited to treat prostate cancer. She and graduate student Natasha DeVore elucidated the structure shown using X-ray crystallography. Dr. Scott created the image (both white bg and transparent bg) for the NIGMS image gallery. See the "Medium-Resolution Image" for a PNG version of the image that is transparent.

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.

A representation of a patient’s brain waves after receiving the anesthetic propofol. All anesthetics create brain wave changes that vary depending on the patient’s age and the type and dose of anesthetic used. These changes are visible in raw electroencephalogram (EEG) readings, but they’re easier to interpret using a spectrogram where the signals are broken down by time (x-axis), frequency (y-axis), and power (color scale). This spectrogram shows the changes in brain waves before, during, and after propofol-induced anesthesia. The patient is unconscious from minute 5, upon propofol administration, through minute 69 (change in power and frequency). But, between minutes 35 and 48, the patient fell into a profound state of unconsciousness (disappearance of dark red oscillations between 8 to 12 Hz), which required the anesthesiologist to adjust the rate of propofol administration. The propofol was stopped at minute 62 and the patient woke up around minute 69.

These six-month-old axolotls, a kind of salamander, glow green and blue under ultraviolet light. That's because they were genetically modified to make harmless green fluorescent protein, or GFP. Like X-ray vision, GFP lets you see inside the axolotls as they hang out in their aquarium. GFP not only can reveal internal structures in living organisms, but it also can light up specific cells and even proteins within a cell. That allows scientists to identify and track things like cancer cells.

Leptospira, shown here in green, is a type (genus) of elongated, spiral-shaped bacteria. Infection can cause Weil's disease, a kind of jaundice, in humans.

Microtubules (magenta) and tau protein (light blue) in a cell model of tauopathy. Researchers believe that tauopathy—the aggregation of tau protein—plays a role in Alzheimer’s disease and other neurodegenerative diseases. This image was captured using Stochastic Optical Reconstruction Microscopy (STORM).

Related to images 6889, 6890, and 6891.

The molecule on the left is an electrostatic potential map of the van der Waals surface of the transition state for human purine nucleoside phosphorylase. The colors indicate the electron density at any position of the molecule. Red indicates electron-rich regions with negative charge and blue indicates electron-poor regions with positive charge. The molecule on the right is called DADMe-ImmH. It is a chemically stable analogue of the transition state on the left. It binds to the enzyme millions of times tighter than the substrate. This inhibitor is in human clinical trials for treating patients with gout. This image appears in Figure 4, Schramm, V.L. (2011) Annu. Rev. Biochem. 80:703-732.

Genome editing using CRISPR/Cas9 is a rapidly expanding field of scientific research with emerging applications in disease treatment, medical therapeutics and bioenergy, just to name a few. This technology is now being used in laboratories all over the world to enhance our understanding of how living biological systems work, how to improve treatments for genetic diseases and how to develop energy solutions for a better future.

Structural biologists create crystals of proteins, shown here, as a first step in a process called X-ray crystallography, which can reveal detailed, three-dimensional protein structures.

Established in 1953, the Coriell Institute for Medical Research distributes cell lines and DNA samples to researchers around the world. Shown here are Coriell's cryogenic tanks filled with liquid nitrogen and millions of vials of frozen cells.

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.

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

Actin (purple), microtubules (yellow), and nuclei (green) are labeled in these cells by immunofluorescence. This image won first place in the Nikon 2003 Small World photo competition.

The structure of the pore-forming protein VDAC-1 from humans. This molecule mediates the flow of products needed for metabolism--in particular the export of ATP--across the outer membrane of mitochondria, the power plants for eukaryotic cells. VDAC-1 is involved in metabolism and the self-destruction of cells--two biological processes central to health.

Related to images 2491, 2494, and 2488.

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.

Cilia (cilium in singular) are complex molecular machines found on many of our cells. One component of cilia is the doublet microtubule, a major part of cilia’s skeletons that give them support and shape. This animated image is a partial model of a doublet microtubule’s structure based on cryo-electron microscopy images. Video can be found here 6549.

The image visualizes a part of the yeast molecular interaction network. The lines in the network represent connections among genes (shown as little dots) and different-colored networks indicate subnetworks, for instance, those in specific locations or pathways in the cell. Researchers use gene or protein expression data to build these networks; the network shown here was visualized with a program called Cytoscape. By following changes in the architectures of these networks in response to altered environmental conditions, scientists can home in on those genes that become central "hubs" (highly connected genes), for example, when a cell encounters stress. They can then further investigate the precise role of these genes to uncover how a cell's molecular machinery deals with stress or other factors. Related to images 3730 and 3733.

It has been said that gastrulation is the most important event in a person's life. This part of early embryonic development transforms a simple ball of cells and begins to define cell fate and the body axis. In a study published in Science magazine in March 2012, NIGMS grantee Bob Goldstein and his research group studied how contractions of actomyosin filaments in C. elegans and Drosophila embryos lead to dramatic rearrangements of cell and embryonic structure. This research is described in detail in the following article: "Triggering a Cell Shape Change by Exploiting Preexisting Actomyosin Contractions." In these images, myosin (green) and plasma membrane (red) are highlighted at four timepoints in gastrulation in the roundworm C. elegans. The blue highlights in the top three frames show how cells are internalized, and the site of closure around the involuting cells is marked with an arrow in the last frame. See related video 3334.

Two adult fruit flies (Drosophila)

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.

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.

A peripheral nerve cell made from human embryonic stem cell-derived neural crest stem cells. The nucleus is shown in blue, and nerve cell proteins peripherin and beta-tubulin (Tuj1) are shown in green and red, respectively. Related to image 3263.

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.

Various views of a zebrafish head with blood vessels shown in purple. Researchers often study zebrafish because they share many genes with humans, grow and reproduce quickly, and have see-through eggs and embryos, which make it easy to study early stages of development.

This video was captured using a light sheet microscope.

Related to image 6934.

Network diagram showing a map of protein-protein interactions in a yeast (Saccharomyces cerevisiae) cell. This cluster includes 78 percent of the proteins in the yeast proteome. The color of a node represents the phenotypic effect of removing the corresponding protein (red, lethal; green, nonlethal; orange, slow growth; yellow, unknown).

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.

Cells walk along body surfaces via tiny "feet," called focal adhesions, that connect with the extracellular matrix. See image 2503 for a labeled version of this illustration.