Women have two X chromosomes (XX) and men have one X and one Y (XY), right? Not always, as you’ll learn from the quiz below. Men can be XX and women can be XY. And many other combinations of X and Y are possible.Continue reading “Chromosomally speaking, what do you know about sex? Take a quiz to find out.”
Happy Fat Tuesday!
On this day, celebrated in many countries with lavish parties and high-fat foods, we’re recognizing the importance of fats in the body.
You’ve probably heard about different types of fat, such as saturated, trans, monounsaturated, omega-3, and omega-6. But fats aren’t just ingredients in food. Along with similar molecules, they fall under the broad term lipids and serve critical roles in the body. Lipids protect your vital organs. They help cells communicate. They launch chemical reactions needed for growth, immune function, and reproduction. They serve as the building blocks of your sex hormones (estrogen and testosterone).
Here we feature five of the hundreds of lipids that are essential to health.Continue reading “Five Fabulous Fats”
When you think of blood, chances are you think of the color red. But blood actually comes in a variety of colors, including red, blue, green, and purple. This rainbow of colors can be traced to the protein molecules that carry oxygen in the blood. Different proteins produce different colors.Continue reading “Roses are red and so is . . . blood?”
In a previous post, we highlighted two NIGMS-funded winners of the 2018 Presidential Award for Excellence in Science, Mathematics and Engineering Mentoring (PAESMEM ). For January’s National Mentoring Month, we tell you about other awardees: J.K. Haynes, Virginia Shepherd, and Maria da Graça H. Vicente.
Ah, December—a month suffused with light-filled holidays, presents, parties . . . and the spread of colds and flu. This playful image uses a festive approach to the serious science of understanding and finding ways to combat the flu virus.
Quick quiz: Which organism . . .
- Can regrow a severed spinal cord?
- Is a culinary delicacy overseas but an invasive pest in the U.S.?
- Reveals insights about tissue regeneration, evolution, and cancer biology?
You’ve probably heard news stories and other talk about CRISPR. If you’re not a scientist—well, even if you are—it can seem a bit complex. Here’s a brief recap of what it’s all about.
In 1987, scientists noticed weird, repeating sequences of DNA in bacteria. In 2002, the abbreviation CRISPR was coined to describe the genetic oddity. By 2006, it was clear that bacteria use CRISPR to defend themselves against viruses. By 2012, scientists realized that they could modify the bacterial strategy to create a gene-editing tool. Since then, CRISPR has been used in countless laboratory studies to understand basic biology and to study whether it’s possible to correct faulty genes that cause disease. Here’s an illustration of how the technique works.
Six NIGMS grantees are among this year’s winners of the Presidential Award for Excellence in Science, Mathematics and Engineering Mentoring (PAESMEM). The award was established by the White House in 1995. This year, it went to 27 individuals and 14 organizations.
PAESMEM recipients were honored during a 3-day event in Washington, D.C. The event featured a gala presentation ceremony and a White House tour. In addition, each winner received a $10,000 grant from the National Science Foundation, which manages PAESMEM on behalf of the White House Office of Science and Technology Policy.
The event also included the first-ever White House State-Federal STEM Education Summit. During the summit, awardees joined leaders in education and workforce development from across the nation, including U.S. territories and several Native American tribes, to discuss trends and future priorities in STEM education. The discussions will inform the development of the next Federal STEM Education 5-Year Strategic Plan, which must be updated every 5 years according to the America COMPETES Reauthorization Act of 2010.
- Ann L. Chester, Ph.D., West Virginia University
- John K. Haynes, Ph.D., Morehouse College
- John A. Pollock, Ph.D., Duquesne University
- Elba Elisa Serrano, Ph.D., New Mexico State University
- Virginia Shepherd, Ph.D., Vanderbilt University
- Maria da Graça H. Vicente, Ph.D., Louisiana State University
Many researchers who search for anti-cancer drugs have labs filled with chemicals and tissue samples. Not Rommie Amaro . Her work uses computers to analyze the shape and behavior of a protein called p53. Defective versions of p53 are associated with more human cancers than any other malfunctioning protein.
Our sense of touch provides us with bits of information about our surroundings that inform the decisions we make. When we touch something, our nervous system transmits signals through nerve endings that feed information to our brain. This enables us to sense the stimulus and take the appropriate action, like drawing back quickly when we touch a hot stovetop.
Bacteria are single cells and lack a nervous system. But like us, they rely on their “sense” of touch to make decisions—or at least change their behavior. For example, bacteria’s sense of touch is believed to trigger the cells to form colonies, called biofilms, on surfaces they make contact with. Bacteria may form biofilms as a way to defend themselves, share limited nutrients, or simply to prevent being washed away in a flowing liquid.
Humans can be harmed by biofilms because these colonies serve as a reservoir of disease-causing cells that are responsible for high rates of human infection. Biofilms can protect at least some cells from being affected by antibiotics. The surviving reservoir of bacteria then have more time to evolve resistance to antibiotics.
At the same time, some biofilms can be valuable; for example, they help to break down waste in water treatment plants and to drive electrical current as part of microbial fuel cells.
Until recently, scientists thought that bacteria formed biofilms and caused infections in response to chemical signals they received from their environments. But research in 2014 showed that the bacterium Pseudomonas aeruginosa could infect a variety of living tissues—from plants to many kinds of animals—simply by making contact with them. In the past year, multiple groups of investigators have learned more about how bacteria sense that they have touched a surface and how that sense translates to changes in their behavior. This understanding could lead to new ways of preventing infections or harmful biofilm formation.
When they first make contact with a surface, bacteria change from free-ranging, swimming cells to stationary ones that secrete a sticky substance, tethering them in one place. To form a biofilm, they begin replicating, creating an organized mass stable enough to resist shaking and to repel potential invaders (see https://biobeat.nigms.nih.gov/2017/01/cool-image-inside-a-biofilm-build-up/).
How do swimming bacteria sense that they have found a potential surface to colonize? Working with the bacterium Caulobacter crescentus, Indiana University Ph.D. student Courtney Ellison and her colleagues, under the direction of professor of biology and NIGMS grantee Yves Brun , recently showed that hair-like structures on the cell’s surface, called pili, play a role here. The researchers found that as a bacterial cell swims in a fluid, its pili are constantly stretching out and retracting. When the cell makes contact with a surface, the pili stop moving, start producing a sticky substance and use it to hold onto the surface. Continue reading “Feeling Out Bacteria’s Sense of Touch”