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.

An axolotl—a type of salamander—that has been genetically modified so that its developing nervous system glows purple and its Schwann cell nuclei appear light blue. Schwann cells insulate and provide nutrients to peripheral nerve cells. Researchers often study axolotls for their extensive regenerative abilities. They can regrow tails, limbs, spinal cords, brains, and more. The researcher who took this image focuses on the role of the peripheral nervous system during limb regeneration.

This image was captured using a stereo microscope.

Related to images 6927 and 6928.

The marine bacterium Vibrio harveyi glows when near its kind. This luminescence, which results from biochemical reactions, is part of the chemical communication used by the organisms to assess their own population size and distinguish themselves from other types of bacteria. But V. harveyi only light up when part of a large group. This communication, called quorum sensing, speaks for itself here on a lab dish, where more densely packed areas of the bacteria show up blue. Other types of bacteria use quorum sensing to release toxins, trigger disease, and evade the immune system.

Gene transcription is a process by which the genetic information encoded in DNA is transcribed into RNA. It's essential for all life and requires the activity of proteins, called transcription factors, that detect where in a DNA strand transcription should start. In eukaryotes (i.e., those that have a nucleus and mitochondria), a protein complex comprising 14 different proteins is responsible for sniffing out transcription start sites and starting the process. This complex, called TFIID, represents the core machinery to which an enzyme, named RNA polymerase, can bind to and read the DNA and transcribe it to RNA. Scientists have used cryo-electron microscopy (cryo-EM) to visualize the TFIID-RNA polymerase-DNA complex in unprecedented detail. In this illustration, TFIID (blue) contacts the DNA and recruits the RNA polymerase (gray) for gene transcription. The start of the transcribed gene is shown with a flash of light. To learn more about the research that has shed new light on gene transcription, see this news release from Berkeley Lab. Related to video 5730.

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 (lateral view).
For imagery of both the lateral and overhead view go to 3556.
For imagery of the overhead view go to 3557.
For more information about the illumated area go to 3559.

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.

Stained cross section of a mouse tail.

This fiery image doesn’t come from inside a bubbling volcano. Instead, it shows animal cells caught in the act of making bubbles, or blebbing. Some cells regularly pinch off parts of their membranes to produce bubbles filled with a mix of proteins and fats. The bubbles (red) are called plasma-derived membrane vesicles, or PMVs, and can travel to other parts of the body where they may aid in cell-cell communication. The University of Texas, Austin, researchers responsible for this photo are exploring ways to use PMVs to deliver medicines to precise locations in the body.

This image, entered in the Biophysical Society’s 2017 Art of Science Image contest, used two-channel spinning disk confocal fluorescence microscopy. It was also featured in the NIH Director’s Blog in May 2017.

This image captures Purkinje cells (red), one of the main types of nerve cell found in the brain. These cells have elaborate branching structures called dendrites that receive signals from other nerve cells.

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

The molecules that glow blue in these cultured cells prevent the expression of the mutant proteins that cause Huntington's disease. Biochemist David Corey and others at UT Southwestern Medical Center designed the molecules to specifically target the genetic repeats that code for harmful proteins in people with Huntington's disese. People with Huntington's disease and similar neurodegenerative disorders often have extra copies of a gene segment. Moving from cell cultures to animals will help researchers further explore the potential of their specially crafted molecule to treat brain disorders. In addition to NIGMS, NIH's National Institute of Neurological Disorders and Stroke and National Institute of Biomedical Imaging and Bioengineering also funded this work.

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 video 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. This video was created for the NIH Director’s Blog post The Amazing Brain: Tracking Molecular Events with Calling Cards.

Related to image 6780.

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 representation of a patient’s brain waves after receiving the anesthetic propofol. All anesthetics create brain wave changes that vary depending on the patient’s age and the type and dose of anesthetic used. These changes are visible in raw electroencephalogram (EEG) readings, but they’re easier to interpret using a spectrogram where the signals are broken down by time (x-axis), frequency (y-axis), and power (color scale). This spectrogram shows the changes in brain waves before, during, and after propofol-induced anesthesia. The patient is unconscious from minute 5, upon propofol administration, through minute 69 (change in power and frequency). But, between minutes 35 and 48, the patient fell into a profound state of unconsciousness (disappearance of dark red oscillations between 8 to 12 Hz), which required the anesthesiologist to adjust the rate of propofol administration. The propofol was stopped at minute 62 and the patient woke up around minute 69.

This image captures the many layers of nerve cells in the retina. The top layer (green) is made up of cells called photoreceptors that convert light into electrical signals to relay to the brain. The two best-known types of photoreceptor cells are rod- and cone-shaped. Rods help us see under low-light conditions but can't help us distinguish colors. Cones don't function well in the dark but allow us to see vibrant colors in daylight.

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

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 3427.

Enzymes convert substrates into products very quickly. See image 2521 for an unlabeled version of this illustration. Featured in The Chemistry of Health.

A model of the molecule himastatin overlaid on an image of Bacillus subtilis bacteria. Scientists first isolated himastatin from the bacterium Streptomyces himastatinicus, and the molecule 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. They also tested the effects of himastatin and derivatives of the molecule on B. subtilis.

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 6848 and video 6851.

Haplotypes are combinations of gene variants that are likely to be inherited together within the same chromosomal region. In this example, an original haplotype (top) evolved over time to create three newer haplotypes that each differ by a few nucleotides (red). See image 2566 for an unlabeled version of this illustration. Featured in The New Genetics.

Human metaphase chromosomes are visible with fluorescence in vitro hybridization (FISH). Centromeric alpha satellite DNA (green) are found in the heterochromatin at each centromere. Immunofluorescence with CENP-A (red) shows the centromere-specific histone H3 variant that specifies the kinetochore.

Meiosis is the process whereby a cell reduces its chromosomes from diploid to haploid in creating eggs or sperm. See image 2546 for a labeled version of this illustration. Featured in The New Genetics.

Duplicated pair of chromosomes lined up and ready to cross over.

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 2514 for other versions of this illustration. Featured in The Structures of Life.

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 is a magnified view of an Arabidopsis thaliana leaf a few days after being exposed to the pathogen Hyaloperonospora arabidopsidis. The plant from which this leaf was taken is genetically resistant to the pathogen. The spots in blue show areas of localized cell death where infection occurred, but it did not spread. Compare this response to that shown in Image 2782. Jeff Dangl has been funded by NIGMS to study the interactions between pathogens and hosts that allow or suppress infection.

In the worm C. elegans, double-stranded RNA made in neurons can silence matching genes in a variety of cell types through the transport of RNA between cells. The head region of three worms that were genetically modified to express a fluorescent protein were imaged and the images were color-coded based on depth. The worm on the left lacks neuronal double-stranded RNA and thus every cell is fluorescent. In the middle worm, the expression of the fluorescent protein is silenced by neuronal double-stranded RNA and thus most cells are not fluorescent. The worm on the right lacks an enzyme that amplifies RNA for silencing. Surprisingly, the identities of the cells that depend on this enzyme for gene silencing are unpredictable. As a result, worms of identical genotype are nevertheless random mosaics for how the function of gene silencing is carried out. For more, see journal article and press release. Related to image 6532.

Cell division is an incredibly coordinated process. It not only ensures that the new cells formed during this event have a full set of chromosomes, but also that they are endowed with all the cellular materials, including proteins, lipids and small functional compartments called organelles, that are required for normal cell activity. This proper apportioning of essential cell ingredients helps each cell get off to a running start.

This image shows an electron microscopy (EM) thin section taken at 10,000x magnification of a dividing yeast cell over-expressing the protein ubiquitin, which is involved in protein degradation and recycling. The picture features mother and daughter endosome accumulations (small organelles with internal vesicles), a darkly stained vacuole and a dividing nucleus in close contact with a cadre of lipid droplets (unstained spherical bodies).  Other dynamic events are also visible,  such as spindle microtubules in the nucleus and endocytic pits at the plasma membrane.

These extensive details were revealed thanks to a preservation method involving high-pressure freezing, freeze-substitution and Lowicryl HM20 embedding.

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

Crystal structure of the beta2-adrenergic receptor protein. This is the first known structure of a human G protein-coupled receptor, a large family of proteins that control critical bodily functions and the action of about half of today's pharmaceuticals. Featured as one of the November 2007 Protein Structure Initiative Structures of the Month.

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 3540.

A two-dimensional NMR spectrum of a protein, in this case a 2D 1H-15N HSQC NMR spectrum of a 228 amino acid DNA/RNA-binding protein.

The receptor is shown bound to a small molecule peptide called CVX15.

This microscopic image shows a chromatin fiber--a DNA molecule bound to naturally occurring proteins.

A knotted protein from an archaebacterium called Methanobacterium thermoautotrophicam. This organism breaks down waste products and produces methane gas. Protein folding theory previously held that forming a knot was beyond the ability of a protein, but this structure, determined at Argonne's Structural Biology Center, proves differently. Researchers theorize that this knot stabilizes the amino acid subunits of the protein.

The cone cell of the eye allows you to see in color. Appears in the NIGMS booklet Inside the Cell.

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. Related to image 3586.
For more information about relapsing fever, see https://www.cdc.gov/relapsing-fever/index.html.
This image is part of the Life: Magnified collection, which was displayed in the Gateway Gallery at Washington Dulles International Airport June 3, 2014, to January 21, 2015.

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.

As this cell was undergoing cell division, it was imaged with two microscopy techniques: differential interference contrast (DIC) and confocal. The DIC view appears in blue and shows the entire cell. The confocal view appears in pink and shows the chromosomes.

A model of a Geobacter sulfurreducens nanowire created from cryo-electron microscopy images. The bacterium conducts electricity through these nanowires, which are made up of protein and iron-containing molecules.

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.

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 version of this illustration that isn't numbered and 2547 for a an entirely unlabeled version. Featured in The New Genetics.

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.

A cell in prophase, near the start of mitosis: In the nucleus, chromosomes condense and become visible. In the cytoplasm, the spindle forms. 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.

X-ray co-crystal structure of Src kinase bound to a DNA-templated macrocycle inhibitor. Related to images 3413, 3414, 3415, 3416, 3417, and 3418.

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.

Cells progress through a cycle that consists of phases for growth (G1, S, and G2) and division (M). Cells become quiescent when they exit this cycle (G0). See image 2498 for an unlabeled version of this illustration.

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.

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.

These mitochondria (red) are from the heart muscle cell of a rat. Mitochondria have an inner membrane that folds in many places (and that appears here as striations). This folding vastly increases the surface area for energy production. Nearly all our cells have mitochondria. Related to image 3664.

These images show three stages of cell division in Xenopus XL177 cells, which are derived from tadpole epithelial cells. They are (from top): metaphase, anaphase and telophase. The microtubules are green and the chromosomes are blue. Related to 3443.

Serum albumin (SA) is the most abundant protein in the blood plasma of mammals. SA has a characteristic heart-shape structure and is a highly versatile protein. It helps maintain normal water levels in our tissues and carries almost half of all calcium ions in human blood. SA also transports some hormones, nutrients and metals throughout the bloodstream. Despite being very similar to our own SA, those from other animals can cause some mild allergies in people. Therefore, some scientists study SAs from humans and other mammals to learn more about what subtle structural or other differences cause immune responses in the body.

Related to entries 3744 and 3746