This image shows mouse fetal heart fibroblast cells. The muscle protein actin is stained red, and the cell nuclei are stained blue. The image was part of a study investigating stem cell-based approaches to repairing tissue damage after a heart attack. Image and caption information courtesy of the California Institute for Regenerative Medicine.

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.

This montage of tiny, transparent C. elegans--or roundworms--may offer insight into understanding human infertility. Researchers used fluorescent dyes to label the worm cells and watch the process of sex cell division, called meiosis, unfold as nuclei (blue) move through the tube-like gonads. Such visualization helps the scientists identify mechanisms that enable these roundworms to reproduce successfully. Because meiosis is similar in all sexually reproducing organisms, what the scientists learn could apply to humans.

This illustration of an epoxide-opening cascade promoted by water emulates the proposed biosynthesis of some of the Red Tide toxins.

The enzyme CCP is found in the mitochondria of baker’s yeast. Scientists study the chemical reactions that CCP triggers, which involve a water molecule, iron, and oxygen. This structure was determined using an X-ray free electron laser.

Yeast cells with nuclear envelopes shown in magenta and tubulin shown in light blue. The nuclear envelope defines the borders of the nucleus, which houses DNA. Tubulin is a protein that makes up microtubules—strong, hollow fibers that provide structure to cells and help direct chromosomes during cell division. This image was captured using wide-field microscopy with deconvolution.

Related to images 6791, 6792, 6793, 6794, 6797, and videos 6795 and 6796.

A macrophage—a type of immune cell that engulfs invaders—“eats” and is activated by a “two-faced” Janus particle. The particle is called “two-faced” because each of its two hemispheres is coated with a different type of molecule, shown here in red and cyan. During macrophage activation, a transcription factor tagged with a green fluorescence protein (NF-κB) gradually moves from the cell’s cytoplasm into its nucleus and causes DNA transcription. The distribution of molecules on “two-faced” Janus particles can be altered to control the activation of immune cells. Details on this “geometric manipulation” strategy can be found in the Proceedings of the National Academy of Sciences paper "Geometrical reorganization of Dectin-1 and TLR2 on single phagosomes alters their synergistic immune signaling" by Li et al. and the Scientific Reports paper "Spatial organization of FcγR and TLR2/1 on phagosome membranes differentially regulates their synergistic and inhibitory receptor crosstalk" by Li et al. This video was captured using epi-fluorescence microscopy.

Related to video 6800.

T cells engulf and digest cells displaying markers (or antigens) for retroviruses, such as HIV.

Molecular model of the struture of heme. Heme is a small, flat molecule with an iron ion (dark red) at its center. Heme is an essential component of hemoglobin, the protein in blood that carries oxygen throughout our bodies. This image first appeared in the September 2013 issue of Findings Magazine. View side view of heme here 3539.

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

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.

In plants, as in animals, stem cells can transform into a variety of different cell types. The stem cells at the growing tip of this Arabidopsis plant will soon become flowers. Arabidopsis is frequently studied by cellular and molecular biologists because it grows rapidly (its entire life cycle is only 6 weeks), produces lots of seeds, and has a genome that is easy to manipulate.

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

This fruit fly expresses green fluorescent protein (GFP) in the same pattern as the period gene, a gene that regulates circadian rhythm and is expressed in all sensory neurons on the surface of the fly.

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.

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

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

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

Related to image 6850 and video 6851.

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.

Each of the tiny colored specs in this image is a cell on the surface of a fish scale. To better understand how wounds heal, scientists have inserted genes that make cells brightly glow in different colors into the skin cells of zebrafish, a fish often used in laboratory research. The colors enable the researchers to track each individual cell, for example, as it moves to the location of a cut or scrape over the course of several days. These technicolor fish endowed with glowing skin cells dubbed "skinbow" provide important insight into how tissues recover and regenerate after an injury.

For more information on skinbow fish, see the Biomedical Beat blog post Visualizing Skin Regeneration in Real Time and a press release from Duke University highlighting this research. Related to image 3782.

These vials may look like they're filled with colored water, but they really contain nanocrystals reflecting different colors under ultraviolet light. The tiny crystals, made of semiconducting compounds, are called quantum dots. Depending on their size, the dots emit different colors that let scientists use them as a tool for detecting particular genes, proteins, and other biological molecules.

Automated crystal screening systems such as the one shown here are becoming a common feature at synchrotron and other facilities where high-throughput crystal structure determination is being carried out. These systems rapidly screen samples to identify the best candidates for further study.

The human skin cells pictured contain genetic modifications that make them pluripotent, essentially equivalent to embryonic stem cells. A scientific team from the University of Wisconsin-Madison including researchers Junying Yu, James Thomson, and their colleagues produced the transformation by introducing a set of four genes into human fibroblasts, skin cells that are easy to obtain and grow in culture.

The three neurons (red) visible in this image were derived from human embryonic stem cells. Undifferentiated stem cells are green here. Image and caption information courtesy of the California Institute for Regenerative Medicine.

Staphylococcus aureus bacteria (green) grouping together upon contact with synovial fluid—a viscous substance found in joints. The formation of groups can help protect the bacteria from immune system defenses and from antibiotics, increasing the likelihood of an infection. This video is a 1-hour time lapse and was captured using a confocal laser scanning microscope.

More information about the research that produced this video can be found in the Journal of Bacteriology paper "In Vitro Staphylococcal Aggregate Morphology and Protection from Antibiotics Are Dependent on Distinct Mechanisms Arising from Postsurgical Joint Components and Fluid Motion" by Staats et al.

Related to images 6803 and 6804.

This is a fibroblast, a connective tissue cell that plays an important role in wound healing. Normal fibroblasts have smooth edges. In contrast, this spiky cell is missing a protein that is necessary for proper construction of the cell's skeleton. Its jagged shape makes it impossible for the cell to move normally. In addition to compromising wound healing, abnormal cell movement can lead to birth defects, faulty immune function, and other health problems.

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

The nucleolus is a small but very important protein complex located in the cell's nucleus. It forms on the chromosomes at the location where the genes for the RNAs are that make up the structure of the ribosome, the indispensable cellular machine that makes proteins from messenger RNAs.

However, how the nucleolus grows and maintains its structure has puzzled scientists for some time. It turns out that even though it looks like a simple liquid blob, it's rather well-organized, consisting of three distinct layers: the fibrillar center, where the RNA polymerase is active; the dense fibrillar component, which is enriched in the protein fibrillarin; and the granular component, which contains a protein called nucleophosmin. Researchers have now discovered that this multilayer structure of the nucleolus arises from differences in how the proteins in each compartment mix with water and with each other. These differences let the proteins readily separate from each other into the three nucleolus compartments.

This video of nucleoli in the eggs of a commonly used lab animal, the frog Xenopus laevis, shows how each of the compartments (the granular component is shown in red, the fibrillarin in yellow-green, and the fibrillar center in blue) spontaneously fuse with each other on encounter without mixing with the other compartments.

For more details on this research, see this press release from Princeton. Related to video 3789, image 3792 and image 3793.

Crystal structure of oligoendopeptidase F, a protein slicing enzyme from Bacillus stearothermophilus, a bacterium that can cause food products to spoil. The crystal was formed using a microfluidic capillary, a device that enables scientists to independently control the parameters for protein crystal nucleation and growth. Featured as one of the July 2007 Protein Structure Initiative Structures of the Month.

The intense X-rays produced by synchrotrons such as the Advanced Photon Source are ideally suited for protein structure determination. Using synchrotron X-rays and advanced computers scientists can determine protein structures at a pace unheard of decades ago.

Time lapse series shows short dynamin assemblies (not visible) constricting a lipid tube to make a "beads on a string" appearance, then cutting off one of the beads i.e., catalyzing membrane fission). The lipids are fluorescent (artificially colored). Ramachandran R, Pucadyil T.J., Liu Y.W., Acharya S., Leonard M., Lukiyanchuk V., Schmid S.L. 2009. Membrane insertion of the pleckstrin homology domain variable loop 1 is critical for dynamin-catalyzed vesicle scission. Mol Biol Cell. 2009 20:4630-9.

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), Arp2 (green), and DAPI to visualize the nucleus (blue). Arp2, a subunit of the Arp2/3 complex, is localized at the lamellipodia leading edge of ARPC3+/+ fibroblast cells. Related to images 3329, 3330, 3331, 3332, and 3333.

Cells keep time to know when to retire.

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.

This image shows the long, branched structures (axons) of nerve cells. Running horizontally across the middle of the photo is an axon wrapped in rings made of actin protein (green), which plays important roles in nerve cells. The image was captured with a powerful microscopy technique that allows scientists to see single molecules in living cells in real time. The technique is called stochastic optical reconstruction microscopy (STORM). It is based on technology so revolutionary that its developers earned the 2014 Nobel Prize in Chemistry. More information about this image can be found in: K. Xu, G. Zhong, X. Zhuang. Actin, spectrin and associated proteins form a periodic cytoskeleton structure in axons. Science 339, 452-456 (2013).

Student Christina Hueneke of the Midwest Center for Structural Genomics is overseeing a protein cloning robot. The robot was designed as part of an effort to exponentially increase the output of a traditional wet lab. Part of the center's goal is to cut the average cost of analyzing a protein from $200,000 to $20,000 and to slash the average time from months to days and hours.

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.

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.

A team of chemists and physicists used nanotechnology and DNA's ability to self-assemble with matching RNA to create a new kind of chip for measuring gene activity. When RNA of a gene of interest binds to a DNA tile (gold squares), it creates a raised surface (white areas) that can be detected by a powerful microscope. This nanochip approach offers manufacturing and usage advantages over existing gene chips and is a key step toward detecting gene activity in a single cell. Featured in the February 20, 2008, issue of Biomedical Beat.

A nanometer-sized biosensor can detect a single deadly bacterium in tainted ground beef. How? Researchers attached nanoparticles, each packed with thousands of dye molecules, to an antibody that recognizes the microbe E. coli O157:H7. When the nanoball-antibody combo comes into contact with the E. coli bacterium, it glows. Here is the transition, a single bacterial cell glows brightly when it encounters nanoparticle-antibody biosensors, each packed with thousands of dye molecules.

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.

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 crawling cell with DNA shown in blue and actin filaments, which are a major component of the cytoskeleton, visible in pink. Actin filaments help enable cells to crawl. This image was captured using structured illumination microscopy.

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 image was captured using a light sheet microscope.

Related to video 6933.

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, 1049, 1050 and 1052.

Scientists from Argonne National Laboratory's Advanced Photon Source (APS) display the first X-ray diffraction pattern obtained from a protein crystal using a split X-ray beam, the first of its kind at APS. The scientists shown are (from left to right): Oleg Makarov, Ruslan Sanishvili, Robert Fischetti (project manager), Sergey Stepanov, and Ward Smith.

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.

The Center for Eukaryotic Structural Genomics protein purification facility is responsible for purifying all recombinant proteins produced by the center. The facility performs several purification steps, monitors the quality of the processes, and stores information about the biochemical properties of the purified proteins in the facility database.

It's probably most people's least favorite activity, but we still need to do it--take out our trash. Otherwise our homes will get cluttered and smelly, and eventually, we'll get sick. The same is true for our cells: garbage disposal is an ongoing and essential activity, and our cells have a dedicated waste-management system that helps keep them clean and neat. One major waste-removal agent in the cell is the lysosome. Lysosomes are small structures, called organelles, and help the body to dispose of proteins and other molecules that have become damaged or worn out.

This image shows a massive accumulation of lysosomes (visualized with LAMP1 immunofluorescence, in purple) within nerve cells that surround amyloid plaques (visualized with beta-amyloid immunofluorescence, in light blue) in a mouse model of Alzheimer's disease. Scientists have linked accumulation of lysosomes around amyloid plaques to impaired waste disposal in nerve cells, ultimately resulting in cell death.

From PDB entry 3c6k, Crystal structure of human spermine synthase in complex with spermidine and 5-methylthioadenosine.

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 research mentor (Lori Eidson) and student (Nina Waldron, on the microscope) were 2009 members of the BRAIN (Behavioral Research Advancements In Neuroscience) program at Georgia State University in Atlanta. This program is an undergraduate summer research experience funded in part by NIGMS.