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.

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.

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.

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

A replica of a human retina grown from stem cells. It shows rod photoreceptors (nerve cells responsible for dark vision) in green and red/green cones (nerve cells responsible for red and green color vision) in red. The cell nuclei are stained blue. This image was captured using a confocal microscope.

Arranging exons in different patterns, called alternative splicing, enables cells to make different proteins from a single gene. See image 2553 for a labeled version of this illustration. Featured in The New Genetics.

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.

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.

The worm Caenorhabditis elegans is a popular laboratory animal because its small size and fairly simple body make it easy to study. Scientists use this small worm to answer many research questions in developmental biology, neurobiology, and genetics. This image, which was taken with transmission electron microscopy (TEM), shows a cross-section through C. elegans, revealing various internal structures labeled in the image. You can find a high-resolution image without the annotations at image 5759.

The image is from a figure in an article published in the journal eLife.

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.

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.

A computer model of the cell membrane, where the plasma membrane is red, endoplasmic reticulum is yellow, and mitochondria are blue. This image relates to a July 27, 2009 article in Computing Life.

These neural precursor cells were derived from human embryonic stem cells. The neural cell bodies are stained red, and the nuclei are blue. Image and caption information courtesy of the California Institute for Regenerative Medicine.

An Arachnoidiscus diatom with a diameter of 190µm. Diatoms are microscopic algae that have cell walls made of silica, which is the strongest known biological material relative to its density. In Arachnoidiscus, the cell wall is a radially symmetric pillbox-like shell composed of overlapping halves that contain intricate and delicate patterns. Sometimes, Arachnoidiscus is called “a wheel of glass.”

This image was taken with the orientation-independent differential interference contrast microscope.

RNA interference or RNAi is a gene-silencing process in which double-stranded RNAs trigger the destruction of specific RNAs. See 2558 for an unlabeled version of this illustration. Featured in The New Genetics.

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

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

This image is a computer-generated model of the approximately 4.2 million atoms of the HIV capsid, the shell that contains the virus' genetic material. Scientists determined the exact structure of the capsid and the proteins that it's made of using a variety of imaging techniques and analyses. They then entered these data into a supercomputer that produced the atomic-level image of the capsid. This structural information could be used for developing drugs that target the capsid, possibly leading to more effective therapies. Related to image 6601.

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

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.

This photo shows a Varian Unity Inova 900 MHz, 21.1 T standard bore magnet Nuclear Magnetic Resonnance (NMR) spectrometer. NMR spectroscopy provides data used to determine the structures of proteins in solution, rather than in crystal form, as in X-ray crystallography. The technique is limited to smaller proteins or protein fragments in a high throughput approach.

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 2494, 2495, and 2488.

Some nerve cells (neurons) in the brain keep track of the daily cycle. This time-keeping mechanism, called the circadian clock, is found in all animals including us. The circadian clock controls our daily activities such as sleep and wakefulness. Researchers are interested in finding the neuron circuits involved in this time keeping and how the information about daily time in the brain is relayed to the rest of the body. In this image of a brain of the fruit fly Drosophila the time-of-day information flowing through the brain has been visualized by staining the neurons involved: clock neurons (shown in blue) function as "pacemakers" by communicating with neurons that produce a short protein called leucokinin (LK) (red), which, in turn, relays the time signal to other neurons, called LK-R neurons (green). This signaling cascade set in motion by the pacemaker neurons helps synchronize the fly's daily activity with the 24-hour cycle. To learn more about what scientists have found out about circadian pacemaker neurons in the fruit fly see this news release by New York University. This work was featured in the Biomedical Beat blog post Cool Image: A Circadian Circuit.

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.

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.

Bean-shaped mitochondria are cells' power plants. These organelles have their own DNA and replicate independently. The highly folded inner membranes are the site of energy generation.

Antibodies are among the most promising therapies for certain forms of cancer, but patients must take them intravenously, exposing healthy tissues to the drug and increasing the risk of side effects. A team of biochemists packed the anticancer antibodies into porous silica particles to deliver a heavy dose directly to tumors in mice.

This is a magnified view of an Arabidopsis thaliana leaf eight days after being infected with the pathogen Hyaloperonospora arabidopsidis, which is closely related to crop pathogens that cause 'downy mildew' diseases. It is also more distantly related to the agent that caused the Irish potato famine. The veins of the leaf are light blue; in darker blue are the pathogen's hyphae growing through the leaf. The small round blobs along the length of the hyphae are called haustoria; each is invading a single plant cell to suck nutrients from the cell. Jeff Dangl and other NIGMS-supported researchers investigate how this pathogen and other like it use virulence mechanisms to suppress host defense and help the pathogens grow.

A colorized scanning electron micrograph of bacteria. Scanning electron microscopes allow scientists to see the three-dimensional surface of their samples.

The two large, central, round shapes are ovaries from a typical fruit fly (Drosophila melanogaster). The small butterfly-like structures surrounding them are fruit fly ovaries where researchers suppressed the expression of a gene that controls microtubule polymerization and is necessary for normal development. This image was captured using a confocal laser scanning microscope.

Related to image 6807.

Georgia Tech associate professor Hang Lu holds a microfluidic chip that is part of a system that uses artificial intelligence and cutting-edge image processing to automatically examine large number of nematodes used for genetic research.

Ribonucleic acid (RNA) has a sugar-phosphate backbone and the bases adenine (A), cytosine (C), guanine (G), and uracil (U). See image 2555 for a labeled version of this illustration. Featured in The New Genetics.

Solution NMR structure of protein target WR41 (left) from C. elegans. Noting the unanticipated structural similarity to the ubiquitin protein (Ub) found in all eukaryotic cells, researchers discovered that WR41 is a Ub-like modifier, ubiquitin-fold modifier 1 (Ufm1), on a newly uncovered ubiquitin-like pathway. Subsequently, the PSI group also determined the three-dimensional structure of protein target HR41 (right) from humans, the E2 ligase for Ufm1, using both NMR and X-ray crystallography.

Zinc is required for the function of more than 300 enzymes, including those that help regulate gene expression, in various organisms including humans. Researchers study how plants acquire, sequester and distribute zinc to find ways to increase the zinc content of crops to improve human health. Using synchrotron X-ray fluorescence technology, they created this heat map of zinc levels in an Arabidopsis thaliana plant leaf. This image is a winner of the 2015 FASEB Bioart contest and was featured in the NIH Director's blog.

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. Historically, researchers have been unable to watch this cell migration unfold in living ovarian tissue in real time. But by developing a culture medium that allows fly eggs to survive outside their ovarian homes, scientists can observe the nuances of cell migration as it happens. Such details may shed light on how immune cells move to a wound and why cancer cells spread to other sites. See 3594 for still image.

Professor Marc Zimmer's family pets, including these fish, glow in the dark in response to blue light. Featured in the September 2009 issue of Findings.

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.

This video simulation shows what an uncontrolled outbreak of transmissible avian flu among people living in Thailand might look like. Red indicates new cases while green indicates areas where the epidemic has finished. The video shows the spread of infection and recovery over 300 days in Thailand and neighboring countries.

On the left, the boundary of a breast tumor (yellow) attaches to collagen fibers that are closest to it (green) using DDR2. On the right, a tumor without DDR2 remains disconnected from the collagen.

Trypanosoma brucei is a single-cell parasite that causes sleeping sickness in humans. Scientists have been studying trypanosomes for some time because of their negative effects on human and also animal health, especially in sub-Saharan Africa. Moreover, because these organisms evolved on a separate path from those of animals and plants more than a billion years ago, researchers study trypanosomes to find out what traits they may harbor that are common to or different from those of other eukaryotes (i.e., those organisms having a nucleus and mitochondria). This image shows the T. brucei cell membrane in red, the DNA in the nucleus and kinetoplast (a structure unique to protozoans, including trypanosomes, which contains mitochondrial DNA) in blue and nuclear pore complexes (which allow molecules to pass into or out of the nucleus) in green. Scientists have found that the trypanosome nuclear pore complex has a unique mechanism by which it attaches to the nuclear envelope. In addition, the trypanosome nuclear pore complex differs from those of other eukaryotes because its components have a near-complete symmetry, and it lacks almost all of the proteins that in other eukaryotes studied so far are required to assemble the pore.

A global "map of the protein structure universe" indicating the positions of specific proteins. The preponderance of small, less-structured proteins near the origin, with the more highly structured, large proteins towards the ends of the axes, may suggest the evolution of protein structures.

3D image of Caulobacter bacterium with various components highlighted: cell membranes (red and blue), protein shell (green), protein factories known as ribosomes (yellow), and storage granules (orange).

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.

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. This is the lateral and overhead (Bottom) view.
For imagery of the overhead view go to 3557.
For imagery of the lateral view go to 3558.
For more information about the illumated area go to 3559.

This map paints a colorful portrait of human genetic variation around the world. Researchers analyzed the DNA of 485 people and tinted the genetic types in different colors to produce one of the most detailed maps of its kind ever made. The map shows that genetic variation decreases with increasing distance from Africa, which supports the idea that humans originated in Africa, spread to the Middle East, then to Asia and Europe, and finally to the Americas. The data also offers a rich resource that scientists could use to pinpoint the genetic basis of diseases prevalent in diverse populations. Featured in the March 19, 2008, issue of Biomedical Beat.

Novel biosensor system maps the timing and location of Rac protein activation in a living mouse embryo fibroblast.

The structure of the endothelium, the thin layer of cells that line our arteries and veins, is visible here. The endothelium is like a gatekeeper, controlling the movement of materials into and out of the bloodstream. Endothelial cells are held tightly together by specialized proteins that function like strong ropes (red) and others that act like cement (blue).

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

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 lined up.

Related to images 1010, 1011, 1012, 1013, 1014, 1015, 1016, 1017, 1018, and 1019.

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.

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.