An adult female Hawaiian bobtail squid, Euprymna scolopes, with its mantle cavity exposed from the underside. Some internal organs are visible, including the two lobes of the light organ that contains bioluminescent bacteria, Vibrio fischeri. The light organ includes accessory tissues like an ink sac (black) that serves as a shutter, and a silvery reflector that directs the light out of the underside of the animal.

Two mouse fibroblasts, one of the most common types of cells in mammalian connective tissue. They play a key role in wound healing and tissue repair. This image was captured using structured illumination microscopy.

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). This frame (4 out of 4) shows a repaired DNA strand with new genetic material that researchers can introduce, which the cell automatically incorporates into the gap when it repairs the broken DNA.

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

HIV is a retrovirus, a type of virus that carries its genetic material not as DNA but as RNA. Long before anyone had heard of HIV, researchers in labs all over the world studied retroviruses, tracing out their life cycle and identifying the key proteins the viruses use to infect cells. When HIV was identified as a retrovirus, these studies gave AIDS researchers an immediate jump-start. The previously identified viral proteins became initial drug targets. See images 2513 and 2515 for other versions of this illustration. Featured in The Structures of Life.

A 3-D model of the alkaloid serratezomine A shows the molecule's complex ring structure.

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.

The photo shows a confocal microscopy image of perineuronal nets (PNNs), which are specialized extracellular matrix (ECM) structures in the brain. The PNN surrounds some nerve cells in brain regions including the cortex, hippocampus and thalamus. Researchers study the PNN to investigate their involvement stabilizing the extracellular environment and forming nets around nerve cells and synapses in the brain. Abnormalities in the PNNs have been linked to a variety of disorders, including epilepsy and schizophrenia, and they limit a process called neural plasticity in which new nerve connections are formed. To visualize the PNNs, researchers labeled them with Wisteria floribunda agglutinin (WFA)-fluorescein. Related to image 3741.

What looks like a Native American dream catcher is really a network of social interactions within a community. The red dots along the inner and outer circles represent people, while the different colored lines represent direct contact between them. All connections originate from four individuals near the center of the graph. Modeling social networks can help researchers understand how diseases spread.

The cerebellum is the brain's locomotion control center. 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.

This image of a mouse cerebellum is part of a collection of such images in different colors and at different levels of magnification from the National Center for Microscopy and Imaging Research (NCMIR). Related to image 5800.

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.

X-ray co-crystal structure of Src kinase bound to a DNA-templated macrocycle inhibitor. Related to 3413, 3415, 3416, 3417, 3418, and 3419.

Composite image of beta-galactosidase showing how cryo-EM’s resolution has improved dramatically in recent years. Older images to the left, more recent to the right. Related to image 5882. NIH Director Francis Collins featured this on his blog on January 14, 2016.

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.

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 2512 for a labeled version of this illustration. Featured in The Structures of Life.

This image shows an abnormal, tetrapolar mitosis. Chromosomes are highlighted pink. The cells shown are S3 tissue cultured cells from Xenopus laevis, African clawed frog.

The arrangement of identical molecular components can make a dramatic difference. For example, carbon atoms can be arranged into dull graphite (left) or sparkly diamonds (right). See image 2507 for an illustration with examples.

A cell in interphase, at the start of mitosis: Chromosomes duplicate, and the copies remain attached to each other. 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.

This illustration shows, in simplified terms, how the CRISPR-Cas9 system can be used as a gene-editing tool. This is the fifthframe in a series of five. 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 NIGMS Biomedical Beat blog entry, Field Focus: Precision Gene Editing with CRISPR and the iBiology video, Genome Engineering with CRISPR-Cas9: Birth of a Breakthrough Technology.

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.

During development, a zebrafish embryo is transformed from a ball of cells into a recognizable body plan by sweeping convergence and extension cell movements. This process is called gastrulation. Each line in this video represents the movement of a single zebrafish embryo cell over the course of 3 hours. The video was created using time-lapse confocal microscopy. Related to image 6775.

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.

A whole yeast (Saccharomyces cerevisiae) cell viewed by X-ray microscopy. Inside, the nucleus and a large vacuole (red) are visible.

Cell mopping up.

In 2006, scientists developed an optical microscopy technique enabling them to clearly see individual molecules within cells. In 2007, they took the technique, abbreviated STORM, a step further. They identified multicolored probes that let them peer into cells and clearly see multiple cellular components at the same time, such as these microtubules (green) and small hollows called clathrin-coated pits (red). Unlike conventional methods, the multicolor STORM technique produces a crisp and high resolution picture. A sharper view of how cellular components interact will likely help scientists answer some longstanding questions about cell biology.

Like a pulsing blue shower, E. coli cells flash in synchrony. Genes inserted into each cell turn a fluorescent protein on and off at regular intervals. When enough cells grow in the colony, a phenomenon called quorum sensing allows them to switch from blinking independently to blinking in unison. Researchers can watch waves of light propagate across the colony. Adjusting the temperature, chemical composition or other conditions can change the frequency and amplitude of the waves. Because the blinks react to subtle changes in the environment, synchronized oscillators like this one could one day allow biologists to build cellular sensors that detect pollutants or help deliver drugs.

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.

In the determination of protein structures by X-ray crystallography, this unique soft (l = 2.29Å) X-ray source is used to collect anomalous scattering data from protein crystals containing light atoms such as sulfur, calcium, zinc and phosphorous. These data can be used to image the protein.

This image shows collagen, a fibrous protein that's the main component of the extracellular matrix (ECM). Collagen is a strong, ropelike molecule that forms stretch-resistant fibers. The most abundant protein in our bodies, collagen accounts for about a quarter of our total protein mass. Among its many functions is giving strength to our tendons, ligaments and bones and providing scaffolding for skin wounds to heal. There are about 20 different types of collagen in our bodies, each adapted to the needs of specific tissues.

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.

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 are starting to separate to form two new cells.

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.
For imagery of both the lateral and overhead view go to 3556.
For imagery of the lateral view go to 3558.
For more information about the illumated area go to 3559.

The nucleus of a human fibroblast cell with chromatin—a substance made up of DNA and proteins—shown in various colors. Fibroblasts are one of the most common types of cells in mammalian connective tissue, and they play a key role in wound healing and tissue repair. This image was captured using Stochastic Optical Reconstruction Microscopy (STORM).

Related to images 6888 and 6893.

A 20-µm thick section of mouse midbrain. The nerve cells are transparent and weren’t stained. Instead, the color is generated by interaction of white polarized light with the molecules in the cells and indicates their orientation.

The image was obtained with a polychromatic polarizing microscope that shows the polychromatic birefringent image with hue corresponding to the slow axis orientation. More information about the microscopy that produced this image can be found in the Scientific Reports paper “Polychromatic Polarization Microscope: Bringing Colors to a Colorless World” by Shribak.

A crane fly spermatocyte during metaphase of meiosis-I, a step in the production of sperm. A meiotic spindle pulls apart three pairs of autosomal chromosomes, along with a sex chromosome on the right. Tubular mitochondria surround the spindle and chromosomes. This video was captured with quantitative orientation-independent differential interference contrast and is a time lapse showing a 1-second image taken every 30 seconds over the course of 30 minutes.

More information about the research that produced this video can be found in the J. Biomed Opt. paper “Orientation-Independent Differential Interference Contrast (DIC) Microscopy and Its Combination with Orientation-Independent Polarization System” by Shribak et. al.

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.

Multiple actin filaments (magenta) are organized around a dynamin helical polymer (rainbow colored) in this model derived from cryo-electron tomography. By bundling actin, dynamin increases the strength of a cell’s skeleton and plays a role in cell-cell fusion, a process involved in conception, development, and regeneration.

Like a world of its own, this sphere represents all the known chemical reactions in the E. coli bacterium. The colorful circles on the surface symbolize sets of densely interconnected reactions. The lines between the circles show additional connecting reactions. The shapes inside the circles are landmark molecules, like capital cities on a map, that either act as hubs for many groups of reactions, are highly conserved among species, or both. Molecules that connect far-flung reactions on the sphere are much more conserved during evolution than molecules that connect reactions within a single circle. This statistical cartography could reveal insights about other complex systems, such as protein interactions and gene regulation networks.

X-ray structure of a DNA repair enzyme superfamily representative from the human gastrointestinal bacterium Enterococcus faecalis. European scientists used this structure to generate homologous structures. Featured as the May 2007 Protein Structure Initiative Structure of the Month.

Collecting and transporting cellular waste and sorting it into recylable and nonrecylable pieces is a complex business in the cell. One key player in that process is the endosome, which helps collect, sort and transport worn-out or leftover proteins with the help of a protein assembly called the endosomal sorting complexes for transport (or ESCRT for short). These complexes help package proteins marked for breakdown into intralumenal vesicles, which, in turn, are enclosed in multivesicular bodies for transport to the places where the proteins are recycled or dumped. In this image, two multivesicular bodies (with yellow membranes) contain tiny intralumenal vesicles (with a diameter of only 25 nanometers; shown in red) adjacent to the cell's vacuole (in orange).

Scientists working with baker's yeast (Saccharomyces cerevisiae) study the budding inward of the limiting membrane (green lines on top of the yellow lines) into the intralumenal vesicles. This tomogram was shot with a Tecnai F-20 high-energy electron microscope, at 29,000x magnification, with a 0.7-nm pixel, ~4-nm resolution.

To learn more about endosomes, see the Biomedical Beat blog post The Cell’s Mailroom. Related to a microscopy photograph 5768 that was used to generate this illustration and a zoomed-out version 5769 of this illustration.

Scanning electron micrograph of an apoptotic HeLa cell. Zeiss Merlin HR-SEM. See related images 3518, 3520, 3521, 3522.

2.5Å resolution reconstruction of rabbit muscle aldolase collected on a FEI/Thermo Fisher Titan Krios with energy filter and image corrector.

Cancer cells can change their migration phenotype, which includes their shape and the way that they move to invade different tissues. This movie shows breast cancer cells forming a tumor spheroid—a 3D ball of cancer cells—and invading the surrounding tissue. Images were taken using a laser scanning confocal microscope, and artificial intelligence (AI) models were used to segment and classify the images by migration phenotype. On the right side of the video, each phenotype is represented by a different color, as recognized by the AI program based on identifiable characteristics of those phenotypes. The movie demonstrates how cancer cells can use different migration modes during growth and metastasis—the spreading of cancer cells within the body.

Microscopy image of a tongue. One in a series of two, see image 5810

Bacillus anthracis (anthrax) cells being killed by a fluorescent trans-translation inhibitor, which disrupts bacterial protein synthesis. The inhibitor is naturally fluorescent and looks blue when it is excited by ultraviolet light in the microscope. This is a black-and-white version of Image 3525.

HIV is a retrovirus, a type of virus that carries its genetic material not as DNA but as RNA. Long before anyone had heard of HIV, researchers in labs all over the world studied retroviruses, tracing out their life cycle and identifying the key proteins the viruses use to infect cells. When HIV was identified as a retrovirus, these studies gave AIDS researchers an immediate jump-start. The previously identified viral proteins became initial drug targets. See images 2514 and 2515 for labeled versions of this illustration. Featured in The Structures of Life.

A zebrafish embryo. The blue areas are cell bodies, the green lines are blood vessels, and the red glow is blood. This image was created by stitching together five individual images captured with a hyperspectral multipoint confocal fluorescence microscope that was developed at the Eliceiri Lab.

NMR solution structure of a plant protein that may function in host defense. This protein was expressed in a convenient and efficient wheat germ cell-free system. Featured as the June 2007 Protein Structure Initiative Structure of the Month.

A robot is transferring 96 purification columns to a vacuum manifold for subsequent purification procedures.

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.

A 360-degree view of the molecule himastatin, which was first isolated from the bacterium Streptomyces himastatinicus. Himastatin shows antibiotic activity. The researchers who created this video developed a new, more concise way to synthesize himastatin so it can be studied more easily.

More information about the research that produced this video can be found in the Science paper “Total synthesis of himastatin” by D’Angelo et al.

Related to images 6848 and 6850.