Although they are tiny, microbes that are growing in confined spaces can generate a lot of pressure. In this video, yeast cells grow in a small chamber called a microfluidic bioreactor. As the cells multiply, they begin to bump into and squeeze each other, resulting in periodic bursts of cells moving into different parts of the chamber. The continually growing cells also generate a lot of pressure--the researchers conducting these experiments found that the pressure generated by the cells can be almost five times higher than that in a car tire--about 150 psi, or 10 times the atmospheric pressure. Occasionally, this pressure even caused the small reactor to burst. By tracking the growth of the yeast or other cells and measuring the mechanical forces generated, scientists can simulate microbial growth in various places such as water pumps, sewage lines or catheters to learn how damage to these devices can be prevented. To learn more how researchers used small bioreactors to gauge the pressure generated by growing microbes, see this press release from UC Berkeley.

Our cells are constantly removing and recycling molecular waste. This video shows one way cells process their trash.

The cerebellum is the brain's locomotion control center. 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.

This image of a mouse cerebellum is part of a collection of such images in different colors and at different levels of magnification from the National Center for Microscopy and Imaging Research (NCMIR). Related to image 5800.

This video shows an instance of abnormal mitosis where chromosomes are late to align. The video demonstrates the spindle checkpoint in action: just one unaligned chromosome can delay anaphase and the completion of mitosis. The cells shown are S3 tissue cultured cells from Xenopus laevis, African clawed frog.

Yeast cells with nuclear envelopes shown in magenta and tubulin shown in light blue. The nuclear envelope defines the borders of the nucleus, which houses DNA. Tubulin is a protein that makes up microtubules—strong, hollow fibers that provide structure to cells and help direct chromosomes during cell division. This image was captured using wide-field microscopy with deconvolution.

Related to images 6791, 6792, 6793, 6794, 6797, and videos 6795 and 6796.

A protein called kinesin (blue) is in charge of moving cargo around inside cells and helping them divide. It's powered by biological fuel called ATP (bright yellow) as it scoots along tube-like cellular tracks called microtubules (gray).

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 absent in the filopodi-like structures based leading edge of ARPC3-/- fibroblasts cells. Related to images 3328, 3330, 3331, 3332, and 3333.

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 6555 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.

Microtubules in African green monkey cells. Microtubules are strong, hollow fibers that provide cells with structural support. Here, the microtubules have been color-coded based on their distance from the microscope lens: purple is closest to the lens, and yellow is farthest away. This image was captured using Stochastic Optical Reconstruction Microscopy (STORM).

Related to images 6889, 6890, and 6892.

Mitochondria are the powerhouses of the cells, generating the energy the cells need to do their tasks and to stay alive. Researchers have studied mitochondria for some time because when these cell organelles don't work as well as they should, several diseases develop. In this photograph of cow cells taken with a microscope, the mitochondria were stained in bright yellow to visualize them in the cell. The large blue dots are the cell nuclei and the gray web is the cytoskeleton of the cells.

Collecting and transporting cellular waste and sorting it into recylable and nonrecylable pieces is a complex business in the cell. One key player in that process is the endosome, which helps collect, sort and transport worn-out or leftover proteins with the help of a protein assembly called the endosomal sorting complexes for transport (or ESCRT for short). These complexes help package proteins marked for breakdown into intralumenal vesicles, which, in turn, are enclosed in multivesicular bodies for transport to the places where the proteins are recycled or dumped. In this image, a multivesicular body (the round structure slightly to the right of center) contain tiny intralumenal vesicles (with a diameter of only 25 nanometers; the round specks inside the larger round structure) adjacent to the cell's vacuole (below the multivesicular body, shown in darker and more uniform gray).

Scientists working with baker's yeast (Saccharomyces cerevisiae) study the budding inward of the limiting membrane (green lines on top of the yellow lines) into the intralumenal vesicles. This tomogram was shot with a Tecnai F-20 high-energy electron microscope, at 29,000x magnification, with a 0.7-nm pixel, ~4-nm resolution.

To learn more about endosomes, see the Biomedical Beat blog post The Cell’s Mailroom. Related to a color-enhanced version 5767 and image 5769.

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.

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.

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.

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 starting to separate to form two new cells.

A cell in anaphase during mitosis: Chromosomes separate into two genetically identical groups and move to opposite ends of the spindle. 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.

A color-coded, 3D model of a rat pancreatic β cell. This type of cell produces insulin, a hormone that helps regulate blood sugar. Visible are mitochondria (pink), insulin vesicles (yellow), the nucleus (dark blue), and the plasma membrane (teal). This model was created based on soft X-ray tomography (SXT) images.

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.

Pigment cells are cells that give skin its color. In fishes and amphibians, like frogs and salamanders, pigment cells are responsible for the characteristic skin patterns that help these organisms to blend into their surroundings or attract mates. The pigment cells are derived from neural crest cells, which are cells originating from the neural tube in the early embryo. This image shows pigment cells in the fin of pearl danio, a close relative of the popular laboratory animal zebrafish. Investigating pigment cell formation and migration in animals helps answer important fundamental questions about the factors that control pigmentation in the skin of animals, including humans. Related to images 5754, 5755, 5756 and 5758.

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.

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. Image created using confocal microscopy.

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

For videos of cell-like compartments from frog eggs view: 6587, 6588, 6589, and 6590.

Learn how research organisms, such as fruit flies and mice, can help us understand and treat human diseases. Discover more resources from NIGMS’ Pathways collaboration with Scholastic. View the video on YouTube for closed captioning.

This image shows neonatal mouse heart cells. These cells were grown in the lab on a chip that aligns the cells in a way that mimics what is normally seen in the body. Green shows the muscle protein toponin I. Red indicates the muscle protein actin, and blue indicates the cell nuclei. The work shown here was part of a study attempting to grow heart tissue in the lab to repair damage after a heart attack. Image and caption information courtesy of the California Institute for Regenerative Medicine. Related to images 3281 and 3282.

Cdc42, a member of the Rho family of small guanosine triphosphatase (GTPase) proteins, regulates multiple cell functions, including motility, proliferation, apoptosis, and cell morphology. In order to fulfill these diverse roles, the timing and location of Cdc42 activation must be tightly controlled. Klaus Hahn and his research group use special dyes designed to report protein conformational changes and interactions, here in living neutrophil cells. Warmer colors in this image indicate higher levels of activation. Cdc42 looks to be activated at cell protrusions.

Related to images 2452, 2453, and 2454.

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.

The HIV capsid is a pear-shaped structure that is made of proteins the virus needs to mature and become infective. The capsid is inside the virus and delivers the virus' genetic information into a human cell. To better understand how the HIV capsid does this feat, scientists have used computer programs to simulate its assembly. This image shows a series of snapshots of the steps that grow the HIV capsid. A model of a complete capsid is shown on the far right of the image for comparison; the green, blue and red colors indicate different configurations of the capsid protein that make up the capsid “shell.” The bar in the left corner represents a length of 20 nanometers, which is less than a tenth the size of the smallest bacterium. Computer models like this also may be used to reconstruct the assembly of the capsids of other important viruses, such as Ebola or the Zika virus. The studies reporting this research were published in Nature Communications and Nature. To learn more about how researchers used computer simulations to track the assembly of the HIV capsid, see this press release from the University of Chicago.

Researchers used cryo-electron tomography (cryo-ET) to capture images of a rat pancreas cell that were then compiled and color-coded to produce a 3D reconstruction. Visible features include the folded sacs of the Golgi apparatus (copper), transport vesicles (medium-sized dark-blue circles), microtubules (neon-green rods), a mitochondria membrane (pink), ribosomes (small pale-yellow circles), endoplasmic reticulum (aqua), and lysosomes (large yellowish-green circles). See 6606 for a still image from the video.

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

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.

Pigment cells are cells that give skin its color. In fishes and amphibians, like frogs and salamanders, pigment cells are responsible for the characteristic skin patterns that help these organisms to blend into their surroundings or attract mates. The pigment cells are derived from neural crest cells, which are cells originating from the neural tube in the early embryo. Investigating pigment cell formation and migration in animals helps answer important fundamental questions about the factors that control pigmentation in the skin of animals, including humans. This image shows a pigment cell from zebrafish at high resolution. Related to images 5755, 5756, 5757 and 5758.

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.

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.

Stained kidney tissue. The kidney is an essential organ responsible for disposing wastes from the body and for maintaining healthy ion levels in the blood. It also secretes two hormones, erythropoietin (EPO) and calcitriol (a derivative of vitamin D), into the blood. It works like a purifier by pulling break-down products of metabolism, such as urea and ammonium, from the blood stream for excretion in urine. Related to image 3725.

The largest human cell (by volume) is the egg. Human eggs are 150 micrometers in diameter and you can just barely see one with a naked eye. In comparison, consider the eggs of chickens...or ostriches!

Force vectors computed from actin cytoskeleton flow. This is an example of NIH-supported research on single-cell analysis. Related to 2798, 2800, 2801, 2802 and 2803.

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

The human immunodeficiency virus (HIV), shown here as tiny purple spheres, causes the disease known as AIDS (for acquired immunodeficiency syndrome). HIV can infect multiple cells in your body, including brain cells, but its main target is a cell in the immune system called the CD4 lymphocyte (also called a T-cell or CD4 cell).

Industrious V. cholerae bacteria (yellow) tend to thrive in denser biofilms (left) while moochers (red) thrive in weaker biofilms (right). More information about the research behind this image can be found in a Biomedical Beat Blog posting from February 2014.

Developing spermatids (precursors of mature sperm cells) begin as small, round cells and mature into long-tailed, tadpole-shaped ones. In the sperm cell's head is the cell nucleus; in its tail is the power to outswim thousands of competitors to fertilize an egg. As seen in this microscopy image, fruit fly spermatids start out as groups of interconnected cells. A small lipid molecule called PIP2 helps spermatids tell their heads from their tails. Here, PIP2 (red) marks the nuclei and a cell skeleton-building protein called tubulin (green) marks the tails. When PIP2 levels are too low, some spermatids get mixed up and grow with their heads at the wrong end. Because sperm development is similar across species, studies in fruit flies could help researchers understand male infertility in humans.

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.

Rendering of the surface of an endothelial cell; membrane curvature is color coded. This is an example of NIH-supported research on single-cell analysis. Related to 2798 , 2799, 357, 2801, and 2802.

Wound healing requires the action of stem cells. In mice that lack the Sept2/ARTS gene, stem cells involved in wound healing live longer and wounds heal faster and more thoroughly than in normal mice. This confocal microscopy image from a mouse lacking the Sept2/ARTS gene shows a tail wound in the process of healing. See more information in the article in Science.

Related to images 3498 and 3500.

Cells progress through a cycle that consists of phases for growth (blue, green, yellow) and division (red). Cells become quiescent when they exit this cycle (purple). See image 2499 for a labeled version of this illustration.

Cells walk along body surfaces via tiny "feet," called focal adhesions, that connect with the extracellular matrix. See image 2502 for an unlabeled version of this illustration.

It's probably most people's least favorite activity, but we still need to do it--take out our trash. Otherwise our homes will get cluttered and smelly, and eventually, we'll get sick. The same is true for our cells: garbage disposal is an ongoing and essential activity, and our cells have a dedicated waste-management system that helps keep them clean and neat. One major waste-removal agent in the cell is the lysosome. Lysosomes are small structures, called organelles, and help the body to dispose of proteins and other molecules that have become damaged or worn out.

This image shows a massive accumulation of lysosomes (visualized with LAMP1 immunofluorescence, in purple) within nerve cells that surround amyloid plaques (visualized with beta-amyloid immunofluorescence, in light blue) in a mouse model of Alzheimer's disease. Scientists have linked accumulation of lysosomes around amyloid plaques to impaired waste disposal in nerve cells, ultimately resulting in cell death.

This animation shows the effect of exposure to hypochlorous acid, which is found in certain types of immune cells, on bacterial proteins. The proteins unfold and stick to one another, leading to cell death.

This pig cell is in the process of dividing. The chromosomes (purple) have already replicated and the duplicates are being pulled apart by fibers of the cell skeleton known as microtubules (green). Studies of cell division yield knowledge that is critical to advancing understanding of many human diseases, including cancer and birth defects.

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

Influenza (flu) virus proteins in the act of self-replication. Viral nucleoprotein (blue) encapsidates [encapsulates] the RNA genome (green). The influenza virus polymerase (orange) reads and copies the RNA genome. In the background is an image of influenza virus ribonucleoprotein complexes observed using cryo-electron microscopy. This image is from a November 2012 News Release.

The fly fatbody is a nutrient storage and mobilization organ akin to the mammalian liver. The engulfment receptor Draper (green) is located at the cell surface of fatbody cells. The cell nuclei are shown in blue.