This video shows 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 videos 2570 and 2572.

Cell-like compartments spontaneously emerge from scrambled frog eggs, with nuclei (blue) from frog sperm. Endoplasmic reticulum (red) and microtubules (green) are also visible. Video created using epifluorescence microscopy.

For more photos of cell-like compartments from frog eggs view: 6584, 6585, 6586, 6591, 6592, and 6593.

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

Normal mice, like the B6 breed pictured on the left, develop scars when their ears are pierced. The Murphy Roths Large (MRL) mice pictured on the right can grow back lost ear tissue thanks to an inactive version of the p21 gene. When researchers knocked out that same gene in other mouse breeds, their ears also healed completely without scarring. Journal Article: Clark, L.D., Clark, R.K. and Heber-Katz, E. 1998. A new murine model for mammalian wound repair and regeneration. Clin Immunol Immunopathol 88: 35-45.

The interior of a regenerating lizard tail 14 days after the original tail was amputated. Cell nuclei (blue), proliferating cells (green), cartilage (red), and muscle (white) have been visualized with immunofluorescence staining.

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.

Fat tissue from the abdomen of a genetically mosaic adult fruit fly. Genetic mosaicism means that the fly has cells with different genotypes even though it formed from a single zygote. This specific mosaicism results in accumulation of a critical fly adipokine (blue-green) within the fat tissue cells that have reduced expression a key nutrient sensing gene (in left panel). The dotted line shows the cells lacking the gene that is present and functioning in the rest of the cells. Nuclei are labelled in magenta. This image was captured using a confocal microscope and shows a maximum intensity projection of many slices.

Related to images 6982, 6984, and 6985.

Just as our bodies rely on bones for structural support, our cells rely on a cellular skeleton. In addition to helping cells keep their shape, this cytoskeleton transports material within cells and coordinates cell division. One component of the cytoskeleton is a protein called tubulin, shown here as thin strands.

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

Like a watch wrapped around a wrist, a special enzyme encircles the double helix to repair a broken strand of DNA. Without molecules that can mend such breaks, cells can malfunction, die, or become cancerous. Related to image 2330.

Floral pattern emerging as two bacterial species, motile Acinetobacter baylyi (red) and non-motile Escherichia coli (green), are grown together for 48 hours on 1% 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 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.
See 6550 for a video of this process.

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.

Model of a protein, antigen 85B, that is the most abundant protein exported by Mycobacterium tuberculosis, which causes most cases of tuberculosis. Antigen 85B is involved in building the bacterial cell wall and is an attractive drug target. Based on its structure, scientists have suggested a new class of antituberculous drugs.

The small intestine is where most of our nutrients from the food we eat are absorbed into the bloodstream. The walls of the intestine contain small finger-like projections called villi which increase the organ's surface area, enhancing nutrient absorption. It consists of the duodenum, which connects to the stomach, the jejenum and the ileum, which connects with the large intestine. Related to image 3389.

Originally from the waters of India, Nepal, and neighboring countries, zebrafish can now be found swimming in science labs (and home aquariums) throughout the world. This fish is a favorite study subject for scientists interested in how genes guide the early stages of prenatal development (including the developing fin shown here) and in the effects of environmental contamination on embryos.

In this image, green fluorescent protein (GFP) is expressed where the gene sox9b is expressed. Collagen (red) marks the fin rays, and DNA, stained with a dye called DAPI, is in blue. sox9b plays many important roles during development, including the building of the heart and brain, and is also necessary for skeletal development. At the University of Wisconsin, researchers have found that exposure to contaminants that bind the aryl-hydrocarbon receptor results in the downregulation of sox9b. Loss of sox9b severely disrupts development in zebrafish and causes a life-threatening disorder called campomelic dysplasia (CD) in humans. CD is characterized by cardiovascular, neural, and skeletal defects. By studying the roles of genes such as sox9b in zebrafish, scientists hope to better understand normal development in humans as well as how to treat developmental disorders and diseases.

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

How far and fast an infectious disease spreads across a community depends on many factors, including transportation. These U.S. maps, developed as part of an international study to simulate and analyze disease spread, chart daily commuting patterns. They show where commuters live (top) and where they travel for work (bottom). Green represents the fewest number of people whereas orange, brown, and white depict the most. Such information enables researchers and policymakers to visualize how an outbreak in one area can spread quickly across a geographic region.

A crystal of bacterial glucose isomerase protein created for X-ray crystallography, which can reveal detailed, three-dimensional protein structures.

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.

Cell-like compartments spontaneously emerge from scrambled frog eggs, with nuclei (blue) from frog sperm. Endoplasmic reticulum (red) and microtubules (green) are also visible. Regions without nuclei formed smaller compartments. Video created using epifluorescence microscopy.

For more photos of cell-like compartments from frog eggs view: 6584, 6585, 6586, 6591, 6592, and 6593.

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

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.

Related to images 1010, 1011, 1012, 1013, 1015, 1016, 1017, 1018, 1019, and 1021.

Glial cells (stained green) in a fruit fly developing embryo have survived thanks to a signaling pathway initiated by neighboring nerve cells (stained red).

Structure of a magnesium transporter protein from an antibiotic-resistant bacterium (Enterococcus faecalis) found in the human gut. Featured as one of the June 2007 Protein Sructure Initiative Structures of the Month.

Details about the basic biology and chemistry of the ingredients that produce bioluminescence are allowing scientists to harness it as an imaging tool. Credit: Nathan Shaner, Scintillon Institute.

From Biomedical Beat article July 2017: Chasing Fireflies—and Better Cellular Imaging Techniques

Mouse embryonic stem cells matured into this bundle of hair cells similar to the ones that transmit sound in the ear. These cells could one day be transplanted as a therapy for some forms of deafness, or they could be used to screen drugs to treat deafness. The hairs are shown at 23,000 times magnification via scanning electron microscopy. Image and caption information courtesy of the California Institute for Regenerative Medicine.

Two fruit fly (Drosophila melanogaster) egg cells, one on each side of the central black line. The colorful swirls show the circular movement of cytoplasm—called ooplasmic streaming—that occurs in late egg cell development in wild-type (right) and mutant (left) oocytes. This image was captured using confocal microscopy.

More information on the research that produced this image can be found in the Journal of Cell Biology paper “Ooplasmic flow cooperates with transport and anchorage in Drosophila oocyte posterior determination” by Lu et al.

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 separating to form the cores of two new cells.

Related to images 1011, 1012, 1013, 1014, 1015, 1016, 1017, 1018, 1019, and 1021.

Cell mopping up.

The new highly efficient parallelized DelPhi software was used to calculate the potential map distribution of an entire virus, the adeno-associated virus, which is made up of more than 484,000 atoms. Despite the relatively large dimension of this biological system, resulting in 815x815x815 mesh points, the parallelized DelPhi, utilizing 100 CPUs, completed the calculations within less than three minutes. Related to image 3375.

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 3742.

A Janus particle being used to activate a T cell, a type of immune cell. A Janus particle is a specialized microparticle with different physical properties on its surface, and this one is coated with nickel on one hemisphere and anti-CD3 antibodies (light blue) on the other. The nickel enables the Janus particle to be moved using a magnet, and the antibodies bind to the T cell and activate it. The T cell in this video was loaded with calcium-sensitive dye to visualize calcium influx, which indicates activation. The intensity of calcium influx was color coded so that warmer color indicates higher intensity. Being able to control Janus particles with simple magnets is a step toward controlling individual cells’ activities without complex magnetic devices.

More details can be found in the Angewandte Chemie paper “Remote control of T cell activation using magnetic Janus particles” by Lee et al. This video was captured using epi-fluorescence microscopy.

Related to video 6801.

When we walk, muscles and nerves interact in intricate ways. This simulation, which is based on data from a six-foot-tall man, shows these interactions.

The fledgling field of X-ray microscopy lets researchers look inside whole cells rapidly frozen to capture their actions at that very moment. Here, a yeast cell buds before dividing into two. Colors show different parts of the cell. Seeing whole cells frozen in time will help scientists observe cells' complex structures and follow how molecules move inside them.

Dose-response curves determine how much of a drug (X-axis) causes a particular effect, or a side effect, in the body (Y-axis). Featured in Medicines By Design.

This short video shows a model of the DNA helicase in yeast. This DNA helicase has 11 proteins that work together to unwind DNA during the process of copying it, called DNA replication. Scientists used a technique called cryo-electron microscopy (cryo-EM), which allowed them to study the helicase structure in solution rather than in static crystals. Cryo-EM in combination with computer modeling therefore allows researchers to see movements and other dynamic changes in the protein. The cryo-EM approach revealed the helicase structure at much greater resolution than could be obtained before. The researchers think that a repeated motion within the protein as shown in the video helps it move along the DNA strand. To read more about DNA helicase and this proposed mechanism, see this news release by Brookhaven National Laboratory.

Colorized scanning electron micrographs progressively zoom in on the eye of a crab larva. In the higher-resolution frames, bacteria are visible on the eye.

These time series show the heart rates of four different individuals. Automakers use steel scraps to build cars, construction companies repurpose tires to lay running tracks, and now scientists are reusing previously discarded medical data to better understand our complex physiology. Through a website called PhysioNet developed in part by Beth Israel Deaconess Medical Center cardiologist Ary Goldberger, scientists can access complete physiologic recordings, such as heart rate, respiration, brain activity and gait. They then can use free software to analyze the data and find patterns in it. The patterns could ultimately help health care professionals diagnose and treat health conditions like congestive heart failure, sleeping disorders, epilepsy and walking problems. PhysioNet is supported by NIH's National Institute of Biomedical Imaging and Bioengineering as well as by NIGMS.

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. Video created using confocal microscopy.

For more photos of cell-like compartments from frog eggs view: 6584, 6585, 6586, 6591, 6592, and 6593.

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

When a molecule arrives at a cell's outer membrane, the membrane creates a pouch around the molecule that protrudes inward. Directed by a protein called dynamin, the pouch then gets pinched off to form a vesicle that carries the molecule to the right place inside the cell. To better understand how dynamin performs its vital pouch-pinching role, researchers determined its structure. Based on the structure, they proposed that a dynamin "collar" at the pouch's base twists ever tighter until the vesicle pops free. Because cells absorb many drugs through vesicles, the discovery could lead to new drug delivery methods.

This network map shows molecular interactions (yellow) associated with a congenital condition that causes heart arrhythmias and the targets for drugs that alter these interactions (red and blue).

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 lower magnification, see image 3639.

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

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 image 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. The technology was also featured in the NIH Director’s Blog post The Amazing Brain: Tracking Molecular Events with Calling Cards.

Related to video

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

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.

Two models for how material passes through the Golgi apparatus: the vesicular shuttle model and the cisternae maturation model.

An RNA molecule dynamically refolds itself as it is being synthesized. When the RNA is short, it ties itself into a “knot” (dark purple). For this domain to slip its knot, about 5 seconds into the video, another newly forming region (fuchsia) wiggles down to gain a “toehold.” About 9 seconds in, the temporarily knotted domain untangles and unwinds. Finally, at about 23 seconds, the strand starts to be reconfigured into the shape it needs to do its job in the cell.

The 46 human chromosomes are shown in blue, with the telomeres appearing as white pinpoints. The DNA has already been copied, so each chromosome is actually made up of two identical lengths of DNA, each with its own two telomeres.

Astrocytes in the cross section of a human optic nerve head

This sculpture made of purple and clear glass beads depicts bacteriophage Phi174, a virus that infects bacteria. It rests on a surface that portrays an adaptive landscape, a conceptual visualization. The ridges represent the gene combinations associated with the greatest fitness levels of the virus, as measured by how quickly the virus can reproduce itself. Phi174 is an important model system for studies of viral evolution because its genome can readily be sequenced as it evolves under defined laboratory conditions.

Crystal structure of a protein with unknown function from Xanthomonas campestris, a plant pathogen. Eight copies of the protein crystallized to form a ring. Chosen as the December 2007 Protein Structure Initiative Structure of the Month.

This crystal structure shows a conserved hypothetical protein from Mycobacterium tuberculosis. Only 12 other proteins share its sequence homology, and none has a known function. This structure indicates the protein may play a role in metabolic pathways. Featured as one of the August 2007 Protein Structure Initiative Structures of the Month.

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

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.