The light organ (~0.5 mm across) of a juvenile Hawaiian bobtail squid, Euprymna scolopes, stained blue. The two pairs of ciliated appendages, or “arms,” on the sides of the organ move Vibrio fischeri bacterial cells closer to the two sets of three pores at the base of the arms that each lead to an interior crypt. This image was taken using a confocal fluorescence microscope.

Related to images 7017, 7018, 7019, and 7020.

Watch a cell ripple toward a beam of light that turns on a movement-related protein.

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.

A white poppy. View cropped image of a poppy here 3423.

This fingertip-shaped group of lights is a microscopic crystal called a quantum dot. About 10,000 times thinner than a sheet of paper, the dot radiates brilliant colors under ultraviolet light. Dots such as this one allow researchers to label and track individual molecules in living cells and may be used for speedy disease diagnosis, DNA testing, and screening for illegal drugs.

Many disease-causing microbes manipulate their host’s metabolism and cells for their own ends. Microsporidia—which are parasites closely related to fungi—infect and multiply inside animal cells, and take the rearranging of cells’ interiors to a new level. They reprogram animal cells such that the cells start to fuse, causing them to form long, continuous tubes. As shown in this image of the roundworm Caenorhabditis elegans, microsporidia (shown in magenta) have invaded the worm’s gut cells (shown in yellow; the cells’ nuclei are shown in blue) and have instructed the cells to merge. The cell fusion enables the microsporidia to thrive and propagate in the expanded space. Scientists study microsporidia in worms to gain more insight into how these parasites manipulate their host cells. This knowledge might help researchers devise strategies to prevent or treat infections with microsporidia. For more on the research into microsporidia, see this news release from the University of California San Diego. Related to images 5778 and 5779.

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.

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.

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. The image shows a side view of the structure of a protein composed of two smaller proteins, called E and M. Each E and M contributes two molecules to the overall protein structure (called a heterotetramer), which is important for assembling and holding together the viral membrane, i.e., the shell that surrounds the genetic material of the dengue virus. The dengue protein's structure has revealed some portions in the protein that might be good targets for developing medications that could be used to combat dengue virus infections. For more on cryo-EM see the blog post Cryo-Electron Microscopy Reveals Molecules in Ever Greater Detail. You can watch a rotating view of the dengue virus surface structure in video 3748.

Three fruit fly (Drosophila melanogaster) ovarioles (yellow, blue, and magenta) with egg cells visible inside them. Ovarioles are tubes in the reproductive systems of female insects. Egg cells form at one end of an ovariole and complete their development as they reach the other end, as shown in the yellow wild-type ovariole. This process requires an important protein that is missing in the blue and magenta ovarioles. This image was created using confocal microscopy.

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.

This is an adult flowering Arabidopsis thaliana plant with the inbred designation L-er. Arabidopsis is the most widely used model organism for researchers who study plant genetics.

CCD-1 is an enzyme produced by the bacterium Clostridioides difficile that helps it resist antibiotics. Using X-ray crystallography, researchers determined the structure of a CCD-1 molecule and a molecule of the antibiotic cefotaxime bound together. The structure revealed that CCD-1 provides extensive hydrogen bonding and stabilization of the antibiotic in the active site, leading to efficient degradation of the antibiotic.

Related to images 6764, 6765, and 6767.

Cells move forward with lamellipodia and filopodia supported by networks and bundles of actin filaments. Proper, controlled cell movement is a complex process. Recent research has shown that an actin-polymerizing factor called the Arp2/3 complex is the key component of the actin polymerization engine that drives amoeboid cell motility. ARPC3, a component of the Arp2/3 complex, plays a critical role in actin nucleation. In this photo, the ARPC3-/- fibroblast cells were fixed and stained with Alexa 546 phalloidin for F-actin (red) and DAPI to visualize the nucleus (blue). In the absence of functional Arp2/3 complex, ARPC3-/- fibroblast cells' leading edge morphology is significantly altered with filopodia-like structures. Related to images 3328, 3329, 3330, 3331, and 3332.

DNA encodes RNA, which encodes protein. DNA is transcribed to make messenger RNA (mRNA). The mRNA sequence (dark red strand) is complementary to the DNA sequence (blue strand). On ribosomes, transfer RNA (tRNA) reads three nucleotides at a time in mRNA to bring together the amino acids that link up to make a protein. See image 2548 for a labeled version of this illustration and 2549 for a labeled and numbered version. Featured in The New Genetics.

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.

This fruit fly spermatid recycles various molecules, including malformed or damaged proteins. Actin filaments (red) in the cell draw unwanted proteins toward a barrel-shaped structure called the proteasome (green clusters), which degrades the molecules into their basic parts for re-use.

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

The nucleus of a degenerating human tendon cell, also known as a tenocyte. It has been color-coded based on the density of chromatin—a substance made up of DNA and proteins. Areas of low chromatin density are shown in blue, and areas of high chromatin density are shown in red. This image was captured using Stochastic Optical Reconstruction Microscopy (STORM).

Related to images 6887 and 6888.

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 line up.

Related to images 1010, 1011, 1012, 1013, 1014, 1015, 1017, 1018, 1019, and 1021.

Pretty in pink, the enzyme histone deacetylase (HDA6) stands out against a background of blue-tinted DNA in the nucleus of an Arabidopsis plant cell. Here, HDA6 concentrates in the nucleolus (top center), where ribosomal RNA genes reside. The enzyme silences the ribosomal RNA genes from one parent while those from the other parent remain active. This chromosome-specific silencing of ribosomal RNA genes is an unusual phenomenon observed in hybrid plants.

This image shows Q fever bacteria (yellow), which infect cows, sheep, and goats around the world and can infect humans, as well. When caught early, Q fever can be cured with antibiotics. A small fraction of people can develop a more serious, chronic form of the disease.

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

A mosquito larva with genes edited by CRISPR. The red-orange glow is a fluorescent protein used to track the edits. 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 6770 and video 6771.

This image captures the spiral-shaped ovary of an anglerfish in cross-section. Once matured, these eggs will be released in a gelatinous, floating mass. For some species of anglerfish, this egg mass can be up to 3 feet long and include nearly 200,000 eggs.

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

Relapsing fever is caused by a bacterium and transmitted by certain soft-bodied ticks or body lice. The disease is seldom fatal in humans, but it can be very serious and prolonged. This scanning electron micrograph shows Borrelia hermsii (green), one of the bacterial species that causes the disease, interacting with red blood cells. Micrograph by Robert Fischer, NIAID.

For more information on this see, relapsing fever.

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

Mitosis creates cells, and apoptosis kills them. The processes often work together to keep us healthy.

Histone proteins loop together with double-stranded DNA to form a structure that resembles beads on a string. See image 2560 for an unlabeled version of this illustration. Featured in The New Genetics.

This image of a mammalian epithelial cell, captured in metaphase, was the winning image in the high- and super-resolution microscopy category of the 2012 GE Healthcare Life Sciences Cell Imaging Competition. The image shows microtubules (red), kinetochores (green) and DNA (blue). The DNA is fixed in the process of being moved along the microtubules that form the structure of the spindle.

The image was taken using the DeltaVision OMX imaging system, affectionately known as the "OMG" microscope, and was displayed on the NBC screen in New York's Times Square during the weekend of April 20-21, 2013. It was also part of the Life: Magnified exhibit that ran from June 3, 2014, to January 21, 2015, at Dulles International Airport.

The "epigenetic code" controls gene activity with chemical tags that mark DNA (purple diamonds) and the "tails" of histone proteins (purple triangles). These markings help determine whether genes will be transcribed by RNA polymerase. Genes hidden from access to RNA polymerase are not expressed. See image 2562 for an unlabeled version of this illustration. Featured in The New Genetics.

Coronaviruses are enveloped viruses responsible for 30 percent of mild respiratory infections and atypical deadly pneumonia in humans worldwide. These deadly pneumonia include those caused by infections with severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). The coronavirus spike glycoprotein mediates virus entry into cells and represents an important therapeutic target. The illustration shows a viral membrane decorated with spike glycoproteins; highlighted in red is a potential neutralization site, which is a protein sequence that might be used as a target for vaccines to combat viruses such as MERS-CoV and other coronaviruses.

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.

RNA interference or RNAi is a gene-silencing process in which double-stranded RNAs trigger the destruction of specific RNAs. See 2559 for a labeled version of this illustration. Featured in The New Genetics.

A model of thymidylate synthase complementing protein from Thermotoga maritime.

Real-time footage of Caenorhabditis elegans, a tiny roundworm, trapped by a carnivorous fungus, Arthrobotrys dactyloides. This fungus makes ring traps in response to the presence of C. elegans. When a worm enters a ring, the trap rapidly constricts so that the worm cannot move away, and the fungus then consumes the worm. The size of the imaged area is 0.7mm x 0.9mm.

This video was obtained with a polychromatic polarizing microscope (PPM) in white light that shows the polychromatic birefringent image with hue corresponding to the slow axis orientation. More information about PPM can be found in the Scientific Reports paper “Polychromatic Polarization Microscope: Bringing Colors to a Colorless World” by Shribak.

A color-coded, 3D model of a rat pancreatic β cell. This type of cell produces insulin, a hormone that helps regulate blood sugar. Visible are mitochondria (pink), insulin vesicles (yellow), the nucleus (dark blue), and the plasma membrane (teal). This model was created based on soft X-ray tomography (SXT) images.

This image results from a research project to visualize which regions of the adult fruit fly (Drosophila) brain derive from each neural stem cell. First, researchers collected several thousand fruit fly larvae and fluorescently stained a random stem cell in the brain of each. The idea was to create a population of larvae in which each of the 100 or so neural stem cells was labeled at least once. When the larvae grew to adults, the researchers examined the flies’ brains using confocal microscopy. With this technique, the part of a fly’s brain that derived from a single, labeled stem cell “lights up. The scientists photographed each brain and digitally colorized its lit-up area. By combining thousands of such photos, they created a three-dimensional, color-coded map that shows which part of the Drosophila brain comes from each of its ~100 neural stem cells. In other words, each colored region shows which neurons are the progeny or “clones” of a single stem cell. This work established a hierarchical structure as well as nomenclature for the neurons in the Drosophila brain. Further research will relate functions to structures of the brain.

Related to image 5868 and video 5843

The TRPA1 protein is responsible for the burn you feel when you taste a bite of sushi topped with wasabi. Known therefore informally as the "wasabi receptor," this protein forms pores in the membranes of nerve cells that sense tastes or odors. Pungent chemicals like wasabi or mustard oil cause the pores to open, which then triggers a tingling or burn on our tongue. This receptor also produces feelings of pain in response to chemicals produced within our own bodies when our tissues are damaged or inflamed. Researchers used cryo-EM to reveal the structure of the wasabi receptor at a resolution of about 4 angstroms (a credit card is about 8 million angstroms thick). This detailed structure can help scientists understand both how we feel pain and how we can limit it by developing therapies to block the receptor. For more on cryo-EM see the blog post Cryo-Electron Microscopy Reveals Molecules in Ever Greater Detail.

Meiosis is used to make sperm and egg cells. During meiosis, a cell's chromosomes are copied once, but the cell divides twice. During mitosis, the chromosomes are copied once, and the cell divides once. For simplicity, cells are illustrated with only three pairs of chromosomes. See image 6788 for a labeled version of this illustration.

Cell-like compartments that spontaneously emerged from scrambled frog eggs. Endoplasmic reticulum (red) and microtubules (green) are visible. Image created using epifluorescence microscopy.

For more photos of cell-like compartments from frog eggs view: 6584, 6585, 6591, 6592, and 6593.

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

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

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 cell nucleus (blue) surrounded by lipid droplets (yellow). Exogenously expressed, S-tagged UBXD8 (green) recruits endogenous p97/VCP (red) to the surface of lipid droplets in oleate-treated HeLa cells. Nucleus stained with DAPI.

For fruit flies, the salivary gland is used to secrete materials for making the pupal case, the protective enclosure in which a larva transforms into an adult fly. For scientists, this gland provided one of the earliest glimpses into the genetic differences between individuals within a species. Chromosomes in the cells of these salivary glands replicate thousands of times without dividing, becoming so huge that scientists can easily view them under a microscope and see differences in genetic content between individuals.

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.

Image showing rhabdomeres (red), the light-sensitive structures in the fruit fly retina, and rhodopsin-4 (blue), a light-sensing molecule.

Detail of a subunit of the capsid, or outer cover, of bacteriophage P22, a virus that infects the Salmonella bacteria. Cryo-electron microscopy (cryo-EM) was used to capture details of the capsid proteins, each shown here in a separate color. Thousands of cryo-EM scans capture the structure and shape of all the individual proteins in the capsid and their position relative to other proteins. A computer model combines these scans into the image shown here. Related to image 5874.

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, 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. 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 image 3297.

RNA polymerase (purple) is a complex enzyme at the heart of transcription. During this process, the enzyme unwinds the DNA double helix and uses one strand (darker orange) as a template to create the single-stranded messenger RNA (green), later used by ribosomes for protein synthesis.

From the RNA polymerase II elongation complex of Saccharomyces cerevisiae (PDB entry 1I6H) as seen in PDB-101's What is a Protein? video.

Crystals of hen egg lysozyme protein created for X-ray crystallography, which can reveal detailed, three-dimensional protein structures.

This 2-hour-old fly embryo already has a blueprint for its formation, and the process for following it is so precise that the difference of just a few key molecules can change the plans. Here, blue marks a high concentration of Bicoid, a key signaling protein that directs the formation of the fly's head. It also regulates another important protein, Hunchback (green), that further maps the head and thorax structures and partitions the embryo in half (red is DNA). The yellow dots overlaying the embryo plot the concentration of Bicoid versus Hunchback proteins within each nucleus. The image illustrates the precision with which an embryo interprets and locates its halfway boundary, approaching limits set by simple physical principles. This image was a finalist in the 2008 Drosophila Image Award.

Phenylalanine tRNA showing the anticodon (yellow) and the amino acid, phenylalanine (blue and red spheres).