'Gram-negative' bacteria: Bugs with extra defenses along their cell walls

Bacteria rapidly evolve (and share) new defenses against drugs they encounter

Unlike humans, bacteria rapidly make genetic changes in response to their environment, including creating defense against antibiotics. Furthermore, these defenses are passed on to their future generations and can even be shared with neighboring bacteria through horizontal gene transfer.

Penicillin works by attacking the cell walls of bacteria

Penicillin targets bacteria at their weakest point—their cell walls. By blocking wall-building, it leaves microbes unable to survive, causing them to burst and die.

Cells are categorized by the presence of contained genetic material and other organelles

While prokaryotes contain one or more cells with free-floating genetic material in a region called the nucleoid, eukaryotes possess a nucleus specialized for DNA storage. Plant cells possess cell walls—a reinforced structure surrounding their membrane—made of cellulose, while fungal cell walls contain chitin. Animal cells have lysosomes housing enzymes that break down biomolecules. (Some readers may experience a paywall.)

How bitter taste receptors help guard against infection

Receptors for "bitter" tastes evolved to detect potentially harmful plant chemicals, such as nicotine. The receptors also trigger bacteria-fighting responses, including waving hairlike projections to bat away bacteria, ordering the release of bacteria-killing nitric oxide, and calling for antimicrobial protein reinforcements.

Researchers generally group gut bacteria into six different categories

The trillions of bacteria in the gut microbiome can be grouped into six categories: firmicutes, actinomycetota, pseudomonadota, fusobacteriota, bacteroides, and a broad miscellaneous category. The functions of each are complex but range from breaking down food and producing vitamins to fighting pathogens.

Drug-resistant staph infection is one of the deadliest superbugs

Methicillin-resistant Staphylococcus aureus (MRSA)—the superbug version of staph infection—is responsible for more deaths than any other superbug, killing more than 120,000 people globally each year. The bug is leading cause of hospital infections, and is harmless on the skin but causes severe symptoms once inside the body.

Plants use physical and chemical defenses to protect themselves

Tree bark is difficult to chew and resistant to pathogens, while the waxy cuticle on the surface of leaves deters insects and microbes. Some plants possess thorns, spines, and prickles to discourage predators. Plant cells can also produce antimicrobial toxins or release compounds to alert parasitic wasps to lay eggs in attacking insects.

Breaking down the challenges of alkaline environments and how extremophiles survive them

These areas are far less acidic than the interiors of most organisms' cells, and this imbalance draws protons that are needed for various metabolic processes, including energy production, out of cells. To counter these effects, some alkaliphiles have developed stronger proton regulation across their cellular membranes and proteins that drive these processes with greater stability amid such acidity imbalances.

Corynebacterium species are particularly responsible for our funky smell

Myriad bacteria contribute to our body odor, but research suggests that Corynebacterium species are strongly associated with the bad smells emanating from adults. Staphylococcus and Cutibacterium genera may also play leading roles.

New species of bacteria discovered in Chinese space station

A new space-adapted bacteria species, Niallia tiangongensis, was discovered on China's Tiangong space station. The bacteria display a heightened oxidative stress response and unique biofilm-forming abilities that assist them in healing from to radiation-based damage.

Probiotics, which are living bacteria and yeasts, are not recommended for most patients

The American Gastroenterological Association in 2020 concluded that although almost 4 million American adults have taken some form of probiotics, health claims about them are not backed in strong evidence. They only recommend their use for a few specific situations: to prevent Clostridioides difficile infection in people taking antibiotics that kill gut bacteria, to prevent necrotizing enterocolitis in preterm infants, and for the management of a complication of inflammatory bowel disease called pouchitis.

A deeper (nontechnical) dive into how CRISPR works

Extra crispy? No, it's CRISPR, but this gene-editing technology is "extra" in the sense of being momentous and destined to change everything. Through CRISPR, scientist exploit a quirk in bacteria immune systems, allowing them to potentially, and quickly, control genes, remove undesirable traits, and add preferred ones. The possibilities and applications are endless.

Why bacterial bioremediation may help counter the negative effects of past chemical solutions

Molecules such as DDT, a synthetic insecticide, and PFAS—"forever" chemicals used to make products resistant to heat, water, and grease—have historically been used across various industries but are now known to be harmful. Microbes that can convert some of these substances into nontoxic products, such as water and carbon dioxide, have already been identified, with ongoing research to find others.

Testing five common beliefs about bedbugs

Bedbugs are one of the most stigmatized pest infestations due to their resilience and tendency to dwell where humans are most unconscious for long periods of time: beds. A bedbug problem can lead to horror stories and intensive interventions to...

An overview on germ theory, the crucial framework developed by Louis Pasteur

Germ theory of disease is based on the concept that many diseases are caused by infections with microorganisms, typically only visualized under high magnification. Read this general overview to understand the basic framework which allowed for development of vaccines.

How slugs helped soldiers during WWI

Slimy, squishy, slow-moving, and heroic? Slugs are land-dwelling mollusks known mostly for causing havoc in our gardens. But during World War I, slugs saved numerous soldier's lives as poison gas detectors. Learn how the unpleasant creatures earned their stripes in the battle to protect soldiers from chlorine, phosgene, and mustard gas as organic detectors.

A macrophage can eat 100 bacteria, on average, before it's exhausted

These specialized immune cells are first responders during inflammation, responding to a threat or injury and then performing other inflammatory response tasks, including summoning neutrophils to help attack invaders.

Explore a gallery of tardigrades

Although sometimes called moss piglets, tardigrades are most often white or clear with some dark pigments. Tardigrades only move by crawling, not swimming, and depictions of organisms with caved-in heads or other coloration result from sample preparation for microscopes.

Dogs smell a lot of stuff we can't, including bed bugs and chemicals in electronic devices

In addition to identifying medical smells and tiny insects like bed bugs, dogs can also detect electronic storage devices. These tools often contain triphenylphosphine oxide, a chemical used to prevent overheating.

What is the blood brain barrier?

Every blood vessel is lined with endothelial cells that act as filters between blood and the rest of the body. In the brain, these cells are tightly packed together to keep a close watch on what substances can access the vital organ. This protective measure poses an obstacle to drugmakers looking to deliver drugs to the well-defended brain for conditions like Alzheimer's. Watch a quick overview here.

See why food poisoning makes you feel nauseous

Scroll through these illustrations to learn what’s happening behind the scenes with bacterial foodborne illnesses, including why we sometimes vomit and how the body reacts to toxins secreted by bacteria.

Leprosy bacteria are sometimes grown on mouse feet for research

The main leprosy-causing bacterium can't be grown in a petri dish, so the disease is challenging to study in the lab. For research purposes, it has been grown in the foot pads of mice.

What exactly is a GMO?

A GMO, or genetically modified organism, is an organism whose DNA has been altered for specific improvement such as longer shelf life, disease resistance, or enhanced nutrition—which can benefit both farmers and consumers. While humans have used...

The world's most unique cheeses

Some are set apart by their unusual ingredients, like moose milk or live mites. Others are defined by texture, like the Georgian specialty tenili, a very rare hand-pulled cheese that resembles yarn or pasta strands. There’s even a canned cheese that has been using the same strain of bacteria for more than 70 years.

Chronic lyme isn't a medically recognized diagnosis in conventional medicine

It describes a constellation of symptoms attributed to a persistent Lyme infection—meaning the bacteria have remained present even after antibiotics. It often occurs among people who have never received a positive test for Lyme. Doctors do recognize "post-treatment Lyme disease syndrome," however, which can include muscle and joint pain, fatigue, and cognitive difficulties after treatment for confirmed Lyme.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

Tattoos remain visible on your skin thanks to immune cells called macrophages

Explore what it's like inside a patient isolation unit, used in situations such as treating a patient or suspected patient with Ebola.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

Prince's sexually explicit 1984 track 'Darling Nikki' attracted the ire of the Parents Music Resource Center, an advocacy group that inspired the Parental Advisory sticker, even though the song ends with a Christian message.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

Massive 3D printers have been used to build homes by stacking layers of 'concrete toothpaste,' a fire-resistant material that effectively insulates against outside noise.

In 2019, a laptop loaded with six of the worst malware in history and described as 'an exhibit of historical weaponry' sold for $1.3M.

During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted, leading authorities to suspect he was conspiring with the Russians.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

After her fellow cult members tried to kill her with an LSD-infused hamburger, one member of the Manson Family, the murderous cult led by Charles Manson, decided to testify against the group's leader.

The Nasdaq's 'Magnificent 7' companies are responsible for roughly 40% of the Nasdaq 100 index's gains, while the remaining 93 companies account for the other 60%.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.