Bacteria

Antibiotics Raise Mortality Risk for Honeybees, Study Finds

Efforts to protect honeybees may be doing more harm than good. Scientists say the antibiotics routinely administered by beekeepers wipe out beneficial bacteria in the bees’ guts, making them vulnerable to other pathogens. They published their findings in the journal PLOS Biology.

These are hard days for honeybees, and apiarists are doing all they can to keep their charge healthy and safe. Twice a year in North America, Asia, and parts of Europe, many beekeepers dose their hives with preventative antibiotics. The drugs may be dusted on the hive or added to the bees’ food to ensure that each insect gets its medicine.

But, as we’re learning in humans, blanket treatment with antibiotics is not really a great option. The more antibiotics we use, the faster pathogens develop antibiotic resistance, and the drugs kill helpful bacteria along with the harmful stuff they’re meant to treat.

Scientists wondered if the same was true for bees. To find out, they brought about 800 bees from long-established hives into the laboratory and split the bees into two groups: the treatment group, marked with a dot of pink paint, and the control group, marked with a…

Scientists Find Evidence of Earth’s Oldest Life

Researchers have discovered hints of life hundreds of millions of years earlier than previously known, according to a new study published in Nature. An international team of scientists led by University College London’s Matthew Dodd have found the oldest microfossils ever in what was once a hydrothermal vent system near Quebec, estimating they could be up to 4.3 billion years old.

Located on the eastern edge of Canada’s Hudson Bay, the Nuvvuagittuq Greenstone Belt is left over from Earth’s earliest oceanic crust. There, within the quartz layers of banded iron formations, the researchers found remains of tubes and filaments (seen attached to a clump of iron in the image below) formed by bacteria on that early crust, which was part of an ancient deep-sea hydrothermal vent network.

The bacterial remnants can be dated back at least…

Bacteria genes offer new strategy for sterilizing mosquitoes

wolbachia bacteria
STERILITY CULPRITS Wolbachia bacteria (red) effectively sterilize a male mosquito by infecting the insect’s testes (blue), shown at 100 times magnification. Now, researchers have identified genes that may be responsible for the sterility.

A pair of bacterial genes may enable genetic engineering strategies for curbing populations of virus-transmitting mosquitoes.

Bacteria that make the insects effectively sterile have been used to reduce mosquito populations. Now, two research teams have identified genes in those bacteria that may be responsible for the sterility, the groups report online February 27 in Nature and Nature Microbiology.

“I think it’s a great advance,” says Scott O’Neill, a biologist with the Institute of Vector-Borne Disease at Monash University in Melbourne, Australia. People have been trying for years to understand how the bacteria manipulate insects, he says.

Wolbachia bacteria “sterilize” male mosquitoes through a mechanism called cytoplasmic incompatibility, which affects sperm and eggs. When an infected male breeds with an uninfected female, his modified sperm kill the eggs after fertilization. When he mates with a likewise infected female, however, her eggs remove the sperm modification and develop normally.

Researchers from Vanderbilt University in Nashville pinpointed a pair of genes, called cifA and cifB, connected to the sterility mechanism of Wolbachia. The genes are located not in the DNA of the bacterium itself, but in a virus embedded in its chromosome.

When the researchers took two genes from the Wolbachia

Bacteria’s amyloids display surprising structure

 amyloid-like clumps made by bacteria
PROTEIN POWER Proteins from Staphylococcus aureus bacteria make amyloid-like clumps (the streamerlike structures in this illustration) that are toxic to human cells.

Clusters of a toxic bacterial protein have a surprising structure, differing from similar clumps associated with Alzheimer’s and Parkinson’s in humans, scientists report in the Feb. 24 Science.

These clusters, called amyloids, are defined in part by their structure: straight regions of protein chains called beta strands, folded accordion-style into flat beta sheets, which then stack up to form a fiber. That definition might now need to be broadened.

“All the amyloids that have been structurally looked at so far have certain characteristics,” says Matthew Chapman, a biologist at the University of Michigan in Ann Arbor who wasn’t part of the work. “This is the odd amyloid out right now.”

In the human brain, misfolded proteins can form amyloids that trigger neurodegenerative diseases. But amyloids aren’t always a sign of something gone wrong — some bacteria make amyloids to help defend their turf.

In Staphylococcus aureus, for example, the PSMα3 protein assembles into amyloids that help the bacteria kill other cells. Previous…

Underwater meadows appear to fight ocean germs

seagrass port
seagrass port

BOSTON, Mass. — Want a lawn that needs no mowing and helps the environment? Look no further than the coastal ocean. Meadows of underwater seagrasses lower the amounts of harmful bacteria that can be found in coastal waters. That’s the finding of a new study reported here, February 16, at the annual meeting of the American Association for the Advancement of Science.

The findings suggest that nurturing healthy seagrass beds throughout coastal waters could make the whole ecosystem healthier — from corals and fish to people.

Seagrasses are not truly grasses. They are flowering plants with long, narrow leaves. Found in shallow ocean waters, they can spread to form vast underwater lawns. These plants are “a marine powerhouse, almost equal to the rainforest,” says says Joleah Lamb, an author of the study. “They’re one of the largest stores of carbon in the ocean,” the ecologist says. “But they don’t get a lot of attention,” she adds. Lamb works at Cornell University, in Ithaca, N.Y.

It’s no secret that seagrasses improve water quality, says James Fourqurean. He’s a biologist at Florida International University in Miami and wasn’t involved in the research.

Scientists had known these plants are great at removing excess nitrogen and phosphorus from coastal waters. Those are nutrients that often run off of the land, polluting coastal waters. Now, it seems, seagrasses might take away harmful germs, too. Lamb’s team describes its findings in the February 17 Science.

What pointed them to the value of these plants

A few years ago, Lamb’s colleagues became ill while studying coral reefs in Indonesia. This archipelago nation straddles the Indian and Pacific oceans. When a city or village on one of the country’s thousands of…

Seagrasses boost ecosystem health by fighting bad bacteria

seagrass
NATURAL CLEANERS Seagrasses, flowering plants that grow in shallow seas, can decrease bacterial contamination in the surrounding water.

BOSTON — For a lawn that helps the environment — and doesn’t need to be mowed — look to the ocean. Meadows of underwater seagrass plants might lower levels of harmful bacteria in nearby ocean waters, researchers reported February 16 during a news conference at the annual meeting of the American Association for the Advancement of Science. That could make the whole ecosystem — from corals to fish to humans — healthier.

Not truly a grass, seagrasses are flowering plants with long, narrow leaves. They grow in shallow ocean water, spreading into vast underwater lawns. Seagrasses are “a marine powerhouse, almost equal to the rainforest. They’re one of the largest stores of carbon in the ocean,” says study coauthor Joleah Lamb, an ecologist at Cornell University. “But they don’t get a lot of attention.”

It’s no secret that seagrasses improve water quality, says James Fourqurean, a biologist at Florida International University in Miami who wasn’t involved in the research, which appears in the Feb. 17 Science. The plants are great at removing excess nitrogen and phosphorus from coastal waters. But now, it seems, they might take away harmful bacteria, too.

A few years ago, Lamb’s colleagues became ill with amoebic dysentery while studying coral reefs in Indonesia, an archipelagic nation that straddles the Indian and Pacific oceans. When a city or village on one of the country’s thousands of islands dumps raw sewage…

The Dirtiest Surfaces in Hotel Rooms

If you head out of town during peak travel season, the odds of you running into an overly filthy hotel room go up. With turnover high and capacity spilling over, stained sheets and bug infestations aren’t uncommon.

But even reputable hotels can harbor some truly unsettling bacterial guests. Online trip calculator TravelMath.com recently conducted a study…

The Weird Event That Led to You and Ewe and Yew

Life arose on earth over three billion years ago, and for a long time, there were only one-celled organisms. These prokaryotes diverged and evolved in many ways, but making the leap from one cell to many cells (eukaryotes) was a paradigm shift that led to every living thing on earth that’s big enough for us to see -including us. How did that happen? Before we could sequence genes, the prevailing theory was a gradual development as cells mutated, diverged, and evolved. However, recent genetic research has led credence to the idea that the first two-celled organism was a merger that only happened once.

The alternative—let’s call it the “sudden-origin” camp—is very different. It dispenses with slow, Darwinian progress and says that eukaryotes were born through the abrupt and dramatic union of two prokaryotes. One was a bacterium. The other was part of the other great lineage of prokaryotes: the archaea. (More about them later.) These two microbes look superficially alike, but they are as different in their biochemistry as PCs…