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.

In the absence of the engulfment receptor Draper, salivary gland cells (light blue) persist in the thorax of a developing Drosophila melanogaster pupa. See image 2758 for a cross section of a normal pupa that does express Draper.

Section of a fruit fly retina showing the light-sensing molecules rhodopsin-5 (blue) and rhodopsin-6 (red).

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.

Along with blood vessels (red) and nerve cells (green), this mouse brain shows abnormal protein clumps known as plaques (blue). These plaques multiply in the brains of people with Alzheimer's disease and are associated with the memory impairment characteristic of the disease. Because mice have genomes nearly identical to our own, they are used to study both the genetic and environmental factors that trigger Alzheimer's disease. Experimental treatments are also tested in mice to identify the best potential therapies for human patients.

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

Each of the 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 3783.

This photograph shows a magnified view of a Drosophila melanogaster pupa in cross section. Compare this normal pupa to one that lacks an important receptor, shown in image 2759.

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 (dark oval shapes) invaded the worm’s gut cells (long tube; the cell nuclei are shown in red) 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 5777 and 5779.

This scanning electron microscope (SEM) image shows podocytes--cells in the kidney that play a vital role in filtering waste from the bloodstream--from a patient with chronic kidney disease. This image first appeared in Princeton Journal Watch on October 4, 2013.

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.

A typical animal cell, sliced open to reveal a cross-section of organelles.

Influenza A infects a host cell when hemagglutinin grips onto glycans on its surface. Neuraminidase, an enzyme that chews sugars, helps newly made virus particles detach so they can infect other cells. Related to 213.

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.

The G switch allows our bodies to respond rapidly to hormones. G proteins act like relay batons to pass messages from circulating hormones into cells. A hormone (red) encounters a receptor (blue) in the membrane of a cell. Next, a G protein (green) becomes activated and makes contact with the receptor to which the hormone is attached. Finally, the G protein passes the hormone's message to the cell by switching on a cell enzyme (purple) that triggers a response. See image 2536 and 2537 for other versions of this image. Featured in Medicines By Design.

This image capture shows how a single gene, STM, plays a starring role in plant development. This gene acts like a molecular fountain of youth, keeping cells ever-young until it’s time to grow up and commit to making flowers and other plant parts. Because of its ease of use and low cost, Arabidopsis is a favorite model for scientists to learn the basic principles driving tissue growth and regrowth for humans as well as the beautiful plants outside your window. Image captured from video Watch Flowers Spring to Life, featured in the NIH Director's Blog: Watch Flowers Spring to Life.

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.

The cryo-EM structure of human adenovirus D26 (HAdV-D26) at near atomic resolution (3.7 Å), determined in collaboration with the NRAMM facility*. In difference to archetype HAdV-C5, the HAdV-D26 is a low seroprevalent viral vector, which is being used to generate Ebola virus vaccines.

Drugs enter different layers of skin via intramuscular, subcutaneous, or transdermal delivery methods. See image 2531 for an unlabeled version of this illustration. Featured in Medicines By Design.

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

The nucleus contains the DNA of eukaryotic cells. The double membrane that bounds the nucleus flows into the rough endoplasmic reticulum, an organelle studded with ribosomes that manufacture membrane-bound proteins for the rest of the cell.

These ripples of color represent the outer membrane of the nucleus inside an astrocyte, a star-shaped cell inside the brain. Some proteins (green) act as keys to unlock other proteins (red) that form gates to let small molecules in and out of the nucleus (blue). Visualizing these different cell components at the boundary of the astrocyte nucleus enables researchers to study the molecular and physiological basis of neurological disorders, such as hydrocephalus, a condition in which too much fluid accumulates in the brain, and scar formation in brain tissue leading to abnormal neuronal activity affecting learning and memory. Scientists have now identified a pathway may be common to many of these brain diseases and begun to further examine it to find ways to treat certain brain diseases and injuries.

This eerily glowing blob isn't an alien or a creature from the deep sea--it's a mouse embryo just eight and a half days old. The green shell and core show a protein called Smad4. In the center, Smad4 is telling certain cells to begin forming the mouse's liver and pancreas. Researchers identified a trio of signaling pathways that help switch on Smad4-making genes, starting immature cells on the path to becoming organs. The research could help biologists learn how to grow human liver and pancreas tissue for research, drug testing and regenerative medicine. In addition to NIGMS, NIH's National Institute of Diabetes and Digestive and Kidney Diseases also supported this work.

Lysosomes (yellow) and detyrosinated microtubules (light blue). Lysosomes are bubblelike organelles that take in molecules and use enzymes to break them down. Microtubules are strong, hollow fibers that provide structural support to cells. The researchers who took this image found that in epithelial cells, detyrosinated microtubules are a small subset of fibers, and they concentrate lysosomes around themselves. This image was captured using Stochastic Optical Reconstruction Microscopy (STORM).

Related to images 6890, 6891, and 6892.

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.

Damage to each person's genome, often called the "Book of Life," accumulates with time. Such DNA mutations arise from errors in the DNA copying process, as well as from external sources, such as sunlight and cigarette smoke. DNA mutations are known to cause cancer and also may contribute to cellular aging.

Top view of myelinated axons in a rat spinal root. Myelin is a type of fat that forms a sheath around and thus insulates the axon to protect it from losing the electrical current needed to transmit signals along the axon. The axoplasm inside the axon is shown in pink. Related to 3396.

The nucleus of a human fibroblast cell with chromatin—a substance made up of DNA and proteins—shown in various colors. Fibroblasts are one of the most common types of cells in mammalian connective tissue, and they play a key role in wound healing and tissue repair. This image was captured using Stochastic Optical Reconstruction Microscopy (STORM).

Related to images 6888 and 6893.

This image shows the structure of a synapse, or junction between two nerve cells in three dimensions. From the brain of a mouse.

On the left, a cross-section slice of a rat pancreas cell captured using cryo-electron tomography (cryo-ET). On the right, a color-coded, 3D version of the image highlighting cell structures. Visible features include insulin vesicles (purple rings), insulin crystals (gray circles), microtubules (green rods), ribosomes (small yellow circles). The black line at the bottom right of the left image represents 200 nm. Related to image 6608.

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.

Two fruit fly (Drosophila melanogaster) larvae brains with neurons expressing fluorescently tagged tubulin protein. Tubulin makes up strong, hollow fibers called microtubules that play important roles in neuron growth and migration during brain development. This image was captured using confocal microscopy, and the color indicates the position of the neurons within the brain.

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.

By attaching fluorescent proteins to the genetic circuit responsible for B. subtilis's stress response, researchers can observe the cells' pulses as green flashes. In response to a stressful environment like one lacking food, B. subtilis activates a large set of genes that help it respond to the hardship. Instead of leaving those genes on as previously thought, researchers discovered that the bacteria flip the genes on and off, increasing the frequency of these pulses with increasing stress. See entry 3254 for the related video.

This illustration shows vesicle traffic inside a cell. The double membrane that bounds the nucleus flows into the ribosome-studded rough endoplasmic reticulum (purple), where membrane-embedded proteins are manufactured. Proteins are processed and lipids are manufactured in the smooth endoplasmic reticulum (blue) and Golgi apparatus (green). Vesicles that fuse with the cell membrane release their contents outside the cell. The cell can also take in material from outside by having vesicles pinch off from the cell membrane.

The incredible complexity of a mammalian eye (in this case from a mouse) is captured here. Each color represents a different type of cell. In total, there are nearly 70 different cell types, including the retina's many rings and the peach-colored muscle cells clustered on the left.

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

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.

Two mouse fibroblasts, one of the most common types of cells in mammalian connective tissue. They play a key role in wound healing and tissue repair. This image was captured using structured illumination microscopy.

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.

A computer model shows how the endoplasmic reticulum is close to and almost wraps around mitochondria in the cell. The endoplasmic reticulum is lime green and the mitochondria are yellow. This image relates to a July 27, 2009 article in Computing Life.

Undifferentiated embryonic stem cells cease to exist a few days after conception. In this image, ES cells are shown to differentiate into sperm, muscle fiber, hair cells, nerve cells, and cone cells.

Cryo-electron microscopy (cryo-EM) has the power to capture details of proteins and other small biological structures at the molecular level.  This image shows proteins in the capsid, or outer cover, of bacteriophage P22, a virus that infects the Salmonella bacteria. Each color shows the structure and position of an individual protein in the capsid. 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 three-dimension image shown here. Related to image 5875.

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.

Multiphoton fluorescence image of HeLa cells stained with the actin binding toxin phalloidin (red), microtubules (cyan) and cell nuclei (blue). Nikon RTS2000MP custom laser scanning microscope. See related images 3518, 3519, 3520, 3522.

Floral pattern emerging as two bacterial species, motile Acinetobacter baylyi and non-motile Escherichia coli (green), are grown together for 72 hours on 0.5% 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 a photo of this process at 48 hours on 1% agar surface.
See 6555 for another photo of this process at 48 hours on 1% agar surface.
See 6550 for a video of this process.

Multicellular yeast called snowflake yeast that researchers created through many generations of directed evolution from unicellular yeast. Stained cell membranes (green) and cell walls (red) reveal the connections between cells. Younger cells take up more cell membrane stain, while older cells take up more cell wall stain, leading to the color differences seen here. This image was captured using spinning disk confocal microscopy.

Related to images 6970 and 6971.

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.

Yeast cells with the protein Fimbrin Fim1 shown in magenta. This protein plays a role in cell division. This image was captured using wide-field microscopy with deconvolution.

Related to images 6791, 6792, 6793, 6797, 6798, and videos 6795 and 6796.

Two healthy cells (bottom, left) enter into apoptosis (bottom, center) but spring back to life after a fatal toxin is removed (bottom, right; top).