These smooth muscle cells were derived from human embryonic stem cells. The nuclei are stained blue, and the proteins of the cytoskeleton are stained green. Image and caption information courtesy of the California Institute for Regenerative Medicine.

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.

To develop a system for studying cell motility in unnatrual conditions -- a microscope slide instead of the body -- Tom Roberts and Katsuya Shimabukuro at Florida State University disassembled and reconstituted the motility parts used by worm sperm cells.

This illustration shows pathogenic bacteria behave like a Trojan horse: switching from antibiotic susceptibility to resistance during infection. Salmonella are vulnerable to antibiotics while circulating in the blood (depicted by fire on red blood cell) but are highly resistant when residing within host macrophages. This leads to treatment failure with the emergence of drug-resistant bacteria.

This image was chosen as a winner of the 2016 NIH-funded research image call, and the research was funded in part by NIGMS.

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.

A microtubule, part of the cell's skeleton, builds and deconstructs.

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.

Fluorescent markers show the interconnected web of tubes and compartments in the endoplasmic reticulum. The protein atlastin helps build and maintain this critical part of cells. The image is from a July 2009 news release.

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.

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.

A fruit fly (Drosophila melanogaster) egg chamber with microtubules shown in green and actin filaments shown in red. Egg chambers are multicellular structures in fruit flies ovaries that each give rise to a single egg. Microtubules and actin filaments give the chambers structure and shape. This image was captured using a confocal microscope.

More information on the research that produced this image can be found in the Current Biology paper "Gatekeeper function for Short stop at the ring canals of the Drosophila ovary" by Lu et al.

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.

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.

Scientists have long known that multicellular organisms use biological molecules produced by one cell and sensed by another to transmit messages that, for instance, guide proper development of organs and tissues. But it's been a puzzle as to how molecules dumped out into the fluid-filled spaces between cells can precisely home in on their targets. Using living tissue from fruit flies, a team led by Thomas Kornberg of the University of California, San Francisco, has shown that typical cells in animals can talk to each other via long, thin cell extensions called cytonemes (Latin for "cell threads") that may span the length of 50 or 100 cells. The point of contact between a cytoneme and its target cell acts as a communications bridge between the two cells.

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.

As an egg cell develops, a process called polarization controls what parts ultimately become the embryo's head and tail. This picture shows an egg of the fruit fly Drosophila. Red and green mark two types of signaling proteins involved in polarization. Disrupting these signals can scramble the body plan of the embryo, leading to severe developmental disorders.

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 3374.

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

Opioid receptors on the surfaces of brain cells are involved in pleasure, pain, addiction, depression, psychosis, and other conditions. The receptors bind to both innate opioids and drugs ranging from hospital anesthetics to opium. Researchers at The Scripps Research Institute, supported by the NIGMS Protein Structure Initiative, determined the first three-dimensional structure of a human opioid receptor, a kappa-opioid receptor. In this illustration, the submicroscopic receptor structure is shown while bound to an agonist (or activator). The structure is superimposed on a poppy flower, the source of opium.

Groups of Staphylococcus aureus bacteria (blue) attached to a microstructured titanium surface (green) that mimics an orthopedic implant used in joint replacement. The attachment of pre-formed groups of bacteria may lead to infections because the groups can tolerate antibiotics and evade the immune system. This image was captured using a scanning electron microscope.

More information on the research that produced this image can be found in the Antibiotics paper "Free-floating aggregate and single-cell-initiated biofilms of Staphylococcus aureus" by Gupta et al.

Related to image 6804 and video 6805.

Three C. elegans, tiny roundworms, with a ribosomal protein glowing red and muscle fibers glowing green. Researchers used these worms to study a molecular pathway that affects aging. The ribosomal protein is involved in protein translation and may play a role in dietary restriction-induced longevity. Image created using confocal microscopy.
View single roundworm here 6581.
View closeup of roundworms here 6583.

A zebrafish embryo showing its natural colors. Zebrafish have see-through eggs and embryos, making them ideal research organisms for studying the earliest stages of development. This image was taken in transmitted light under a polychromatic polarizing microscope.

Viral RNA (red) in an RSV-infected cell. More information about the research behind this image can be found in a Biomedical Beat Blog posting from January 2014.

Arranging exons in different patterns, called alternative splicing, enables cells to make different proteins from a single gene. Featured in The New Genetics.

See image 2552 for an unlabeled version of this illustration.

Motor neuron progenitors (green) were derived from human embryonic stem cells. Image and caption information courtesy of the California Institute for Regenerative Medicine.

After multiplying inside a host cell, the stringlike Ebola virus is emerging to infect more cells. Ebola is a rare, often fatal disease that occurs primarily in tropical regions of sub-Saharan Africa. The virus is believed to spread to humans through contact with wild animals, especially fruit bats. It can be transmitted between one person and another through bodily fluids.

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

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.

The G switch allows our bodies to respond rapidly to hormones. See images 2537 and 2538 for labeled versions of this image. Featured in Medicines By Design.

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.

A white poppy. View cropped image of a poppy here 3423.

This is an adult flowering Arabidopsis thaliana plant with the inbred designation L-er. Arabidopsis is the most widely used model organism for researchers who study plant genetics.

In SARS-CoV-2, the virus that causes COVID-19, nucleocapsid is a complex molecule with many functional parts. One section folds into an RNA-binding domain, with a groove that grips a short segment of the viral genomic RNA. Another section folds into a dimerization domain that brings two nucleocapsid molecules together. The rest of the protein is intrinsically disordered, forming tails at each end of the protein chain and a flexible linker that connects the two structured domains. These disordered regions assist with RNA binding and orchestrate association of nucleocapsid dimers into larger assemblies that package the RNA in the small space inside virions. Nucleocapsid is in magenta and purple, and short RNA strands are in yellow.

Find these in the RCSB Protein Data Bank: RNA-binding domain (PDB entry 7ACT) and Dimerization domain (PDB entry 6WJI).

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). ARPC3+/+ fibroblast cells with lamellipodia leading edge. Related to images 3328, 3329, 3330, 3331, and 3333.

This graphic that resembles a firework was created from a picture of a fruit fly spermatid. This fruit fly spermatid recycles various molecules, including malformed or damaged proteins. Actin filaments (red) in the cell draw unwanted proteins toward a barrel-shaped structure called the proteasome (green clusters), which degrades the molecules into their basic parts for re-use.

Human embryonic stem cells differentiated into dopaminergic neurons, the type that degenerate in Parkinson's disease. Image courtesy of the California Institute for Regenerative Medicine. Related to images 3271 and 3285.

Hippocampal neuron in culture. Dendrites are green, dendritic spines are red and DNA in cell's nucleus is blue. Image is featured on Biomedical Beat blog post Anesthesia and Brain Cells: A Temporary Disruption?

Image of Streptococcus, a type (genus) of spherical bacteria that can colonize the throat and back of the mouth. Stroptococci often occur in pairs or in chains, as shown here.

Blood vessels at the back of the eye (retina) are used to diagnose glaucoma and diabetic eye disease. They also display characteristic changes in people with high blood pressure. In the image, the vessels appear green. It's not actually the vessels that are stained green, but rather filaments of a protein called actin that wraps around the vessels. Most of the red blood cells were replaced by fluid as the tissue was prepared for the microscope. The tiny red dots are red blood cells that remain in the vessels. The image was captured using confocal and 2-photon excitation microscopy for a project related to neurofibromatosis.

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.

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 have lined up in the middle of the dividing cell.

Related to images 1010, 1011, 1012, 1013, 1014, 1015, 1016, 1018, 1019, and 1021.

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.

A study published in March 2012 used cryo-electron microscopy to determine the structure of the DNA replication origin recognition complex (ORC), a semi-circular, protein complex (yellow) that recognizes and binds DNA to start the replication process. The ORC appears to wrap around and bend approximately 70 base pairs of double stranded DNA (red and blue). Also shown is the protein Cdc6 (green), which is also involved in the initiation of DNA replication. The video shows the structure from different angles. See related image 3597.

This image shows the hierarchical ontology of genes, cellular components and processes derived from large genomic datasets. From Dutkowski et al. A gene ontology inferred from molecular networks Nat Biotechnol. 2013 Jan;31(1):38-45. Related to 3437.

Image of the colon of a mouse mono-colonized with Bacteroides fragilis (red) residing within the crypt channel. The red staining is due to an antibody to B. fragilis, the green staining is a general dye for the mouse cells (phalloidin, which stains F-actin) and the light blue glow is from a dye for visualizing the mouse cell nuclei (DAPI, which stains DNA). Bacteria from the human microbiome have evolved specific molecules to physically associate with host tissue, conferring resilience and stability during life-long colonization of the gut. Image is featured in October 2015 Biomedical Beat blog post Cool Images: A Halloween-Inspired Cell Collection.

The image visualizes a part of the yeast molecular interaction network. The lines in the network represent connections among genes (shown as little dots) and different-colored networks indicate subnetworks, for instance, those in specific locations or pathways in the cell. Researchers use gene or protein expression data to build these networks; the network shown here was visualized with a program called Cytoscape. By following changes in the architectures of these networks in response to altered environmental conditions, scientists can home in on those genes that become central "hubs" (highly connected genes), for example, when a cell encounters stress. They can then further investigate the precise role of these genes to uncover how a cell's molecular machinery deals with stress or other factors. Related to images 3730 and 3732.

This fluorescent microscope image shows human embryonic stem cells whose nuclei are stained green. Blue staining shows the surrounding supportive feeder cells. Image and caption information courtesy of the California Institute for Regenerative Medicine. See related image 3275.

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

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

Coronaviruses are enveloped viruses responsible for 30 percent of mild respiratory infections and atypical deadly pneumonia in humans worldwide. These deadly pneumonia include those caused by infections with severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). The coronavirus spike glycoprotein mediates virus entry into cells and represents an important therapeutic target. The illustration shows a viral membrane decorated with spike glycoproteins; highlighted in red is a potential neutralization site, which is a protein sequence that might be used as a target for vaccines to combat viruses such as MERS-CoV and other coronaviruses.

Spinal nerves are part of the peripheral nervous system. They run within the spinal column to carry nerve signals to and from all parts of the body. The spinal nerves enable all the movements we do, from turning our heads to wiggling our toes, control the movements of our internal organs, such as the colon and the bladder, as well as allow us to feel touch and the location of our limbs.