Formation of a biofilm often involves a process called quorum sensing. In this process, microbes detect when they reach a certain population density and change their behavior in ways that help them function as a community.
Josephine (Josie) Chandler, Ph.D., first became interested in science when she took a high school chemistry class. In college, she fell in love with microbiology and ultimately earned a Ph.D. in the field. Today, she’s an associate professor of molecular biosciences at the University of Kansas in Lawrence, where her lab investigates interactions in bacterial communities. By better understanding these interactions, scientists may find new ways to stop infections or break down environmental pollutants—a process known as bioremediation.
NIGMS, in collaboration with Scholastic, has developed a collection of free biology and health activities on the educational app Kahoot! You can play them alone, with friends, or with a class of students. Four Kahoots! are currently available:
Some bacteria benefit us as part of our microbiome—the vast collection of microorganisms that live in and on our bodies—while others can make us sick. Whether helpful or dangerous, bacteria can appear colorful and striking under a microscope. These photos provide just a small peek into the incredible diversity of these microbes.
Credit: Liyang Xiong and Lev Tsimring, BioCircuits Institute, UCSD.
This floral pattern emerged when a researcher grew two strains of bacteria—Acinetobacter baylyi (red) and Escherichia coli (green)—together for 2 days in a petri dish. A. baylyi are found in soil and typically don’t pose a threat to humans, although some strains can cause infections. E. coli normally live in the intestines of people and animals. Most strains are harmless, but some can cause food poisoning or other illnesses.
A cone snail shell. Credit: Kerry Matz, University of Utah.
Over the years, scientists have discovered many compounds in nature that have led to the development of medications. For instance, the molecular structure for aspirin came from willow tree bark, and penicillin was found in a type of mold. And uses of natural products aren’t limited to medicine cabinet staples and antibiotics. A cancer drug was originally found in the bark of the Pacific yew tree, and a medication for chronic pain relief was first isolated from cone snail venom. Today, NIGMS supports scientists in the earliest stages of investigating natural products made by plants, fungi, bacteria, and animals. The results could inform future research and bring advances to the field of medicine.
Research on how diet impacts the gut microbiota has rapidly expanded in the last several years. Studies show that diets rich in red meat are linked to diseases such as colon cancer and heart disease. In both mice and humans, researchers have recently discovered differences in the gut microbiota of those who eat diets rich in red meat compared with those who don’t. This is likely because of a sugar molecule in the red meat, called N-glycolylneuraminic acid (Neu5Gc), that our bodies can’t break down. Researchers believe the human immune system sees Neu5Gc as foreign. This triggers the immune system, causing inflammation in the body, and possibly leads to disease over time.
Blake Wiedenheft Grew up in: Fort Peck, Montana Fields: Microbiology, biochemistry, structural biology Job site: Montana State University Secret talent: Being a generalist; enjoying many different subjects and activities When not in the lab, he’s: Running, biking, skiing or playing scrabble with his grandmother
Scientific discoveries are often stories of adventure. This is the realization that set Blake Wiedenheft on a path toward one of the hottest areas in biology.
His story begins in Montana, where he grew up and now lives. Always exploring different interests, Wiedenheft decided in his final semester at Montana State University (MSU) in Bozeman to volunteer for Mark Young, a scientist who studies plant viruses. Even though he majored in biology, Wiedenheft had spent little time in a lab and hadn’t even considered research as a career option. Continue reading “Finding Adventure: Blake Wiedenheft’s Path to Gene Editing”
Last month, we shared some facts about the microbes that inhabit us. Here’s another: From head to toe, our skin bacteria coexist with chemicals in hygiene products, fibers from clothes and proteins shed by dead or dying skin cells.
Trillions of microorganisms inhabit us—inside and out. Scientists are surveying these microbial metropolises to learn more about their role in health. Microbiologists Darren Sledjeski of NIGMS and Andrew Goodman of Yale University share a few details of what researchers have learned so far.
Researchers are surveying the microbes that inhabit us to learn more about their role in health. Credit: Andrew Goodman, Yale University.
The majority of the microbes that inhabit us are bacteria. The rest of the microbial menagerie is fungi and viruses, including ones that infect the bacteria! Collectively, our resident microorganisms are referred to as the human microbiota, and their genomes are called the human microbiome.
Our bodies harbor more bacterial cells than human ones. Even so, the microbiota accounts for less than 3 percent of a person’s body mass. That’s because our cells are up to 10,000 times bigger in volume than bacterial cells.
Your collection of bacteria has more genes than you do. Scientists estimate that the genomes of gut bacteria contain 100-fold or more genes than our own genomes. For this reason, the human microbiome is sometimes called our second genome.
Most of our microbes are harmless, and some are helpful. For example, harmless microbes on the skin keep infectious microbes from occupying that space. Microbes in the colon break down lactose and other complex carbohydrates that our bodies can’t naturally digest.
Different microbes occupy different parts of the body. Some skin bacteria prefer the oily nooks near the nose, while others like the dry terrain of the forearm. Bacteria don’t all fare well in the same environment and have adapted to live in certain niches. The NIGMS Findings Magazine article Body Bacteria: Exploring the Skin’s Microbial Metropolis shows what types of bacteria colonize where.
Are we more microbial than human? Richard Losick, a microbiologist at Harvard University, explores that question in this video lecture produced by iBiology .
Each person’s microbiota is unique. The demographics of microbiota differ among individuals. Diet is one reason. Also, while a type of microbe might be part of one person’s normal microbial flora, it might not be part of another’s, and could potentially make that person sick.
Host-microbial interactions are universal. Microbial communities may vary from person to person, but everyone’s got them, including other creatures. For this reason, researchers can use model organisms to tease apart the complexities of host-microbial interactions and develop broad principles for understanding them. The mouse is the most widely used animal model for microbiome studies.
The role of microbiota in our health isn’t entirely clear. While it’s now well accepted that the microbial communities that inhabit us are actively involved in a range of conditions—from asthma to obesity—research studies have not yet pinpointed why or how. In other words, the results may suggest that the presence of a bacterial community is associated with a disease, but they don’t show cause and effect.
Most of our microbes have not been grown in the lab. Microbes require a certain mix of nutrients and other microbes to survive, making it challenging to replicate their natural environments in a petri dish. New culturing techniques are enabling scientists to study previously uncultivated microbes.
The impact of probiotic and prebiotic products isn’t clear. Fundamental knowledge gaps remain regarding how these products may work and what effects they might have on host-microbial interactions. A new NIH effort to stimulate research in this area is under way.
There’s even more we don’t know! Additional areas of research include studying the functions of microbial genes and the effects of gut microbes on medicines. The more we learn from these and other studies, the more we’ll understand how our normal microbiota interacts with us and how to apply that knowledge to promote our health.
A biofilm of bacteria and fungi, commonly known as a rind, forms on the surface of traditionally aged cheeses. Credit: Elia Ben-Ari.
Biofilms—multispecies communities of microbes that live in and on us, and in the environment—are important for human health and the function of ecosystems. But studying these microbial metropolises can be challenging because many of the environments where they’re found are hard to replicate in the lab.
Enter cheese rinds. These biofilms of bacteria and fungi form on the surface of traditionally aged cheeses, and could serve as a system for understanding how microbial communities form and function. By sequencing DNA from the rinds of 137 artisan cheese varieties collected in 10 countries, Rachel Dutton and her colleagues at Harvard University identified three general types of microbial communities that live on their tasty study subjects. After individually culturing representatives of all the species found in the rind communities the scientists added them to a growth medium that included cheese curd. This approach allowed them to recreate the communities in the lab and use them to detect numerous bacterial-fungal interactions and patterns of community composition over time.
The scientists plan to use their lab-grown cheese rinds to study whether and how various microbes compete or cooperate as they form communities, as well as what molecules and mechanisms are involved. In addition to answering fundamental questions about microbial ecology, this cheesy research might ultimately yield insights that help fight infection-causing biofilms or lead to the discovery of new antibiotics.