pv:bacteria

sciencealert.com
Bacterial cells are actually the world's smallest 'eyeballs', scientists discover by accident
Ever feel like you're being watched?
By Peter Dockrill

In a surprise discovery, scientists have found that bacteria see the world in effectively the same way as humans, with bacterial cells acting as the equivalent of microscopic eyeballs.

British and German researchers made the finding by accident when studying aquatic cyanobacteria, which sometimes form a green film on rocks and pebbles. Scientists already knew the bacteria could perceive the position of a light source and move towards it – a phenomenon called phototaxis – but before now, no one understood how they did it.

“We noticed it accidentally, because we had cells on a surface and we were shining light from one side, in order to watch the movement towards the light,” microbiologist Conrad Mullineaux from Queen Mary University of London told Jonathan Webb at BBC News. “We suddenly saw these focused bright spots [inside the cells] and we thought, ‘bloody hell!’ Immediately, it was pretty obvious what was going on.”

What the researchers discovered when studying Synechocystis – a species of cyanobacteria found in freshwater lakes and rivers – is that their cell bodies act like a lens. When light hits the spherical surface of the cell, it refracts into a point on the other side of the cell. This triggers movement by the cell away from the focused internal spot, towards the source of the light, with the cells using tiny tentacle-like structures called pili to pull themselves forwards.

Continue Reading.

4

Microbial art shows how bacteria became the most successful organism on Earth

In an attempt to unravel bacteria’s remarkable adaptive abilities, the late UC San Diego theoretical physicist and chemist Eshel Ben-Jacobs also stumbled upon a new form of art.

Ben-Jacobs grew species of bacteria in his lab and exposed them to stresses such as temperature changes, antibiotics and food scarcity in an effort to understand how they behave and cope under different environmental conditions.

What resulted were formations that indicate the different ways bacterial colonies communicate, react and make decisions about where to expand in a petri dish.

While the colors are his artistic addition, “the strikingly beautiful organization of the pattern reflects the underlying social intelligence of the bacteria,” said Ben-Jacobs.

Take a look at his gallery of microbial art

Slime can see                

After more than 300 years of looking, scientists have figured out how bacteria “see” their world. And they do it in a remarkably similar way to us.

A team of British and German researchers reveal in the journal eLife how bacterial cells act as the equivalent of a microscopic eyeball or the world’s oldest and smallest camera eye.

“The idea that bacteria can see their world in basically the same way that we do is pretty exciting,” says lead researcher Conrad Mullineaux, Professor of Microbiology from QMUL’s School of Biological and Chemical Sciences from Queen Mary University of London (QMUL).

Caption:  Bacteria are optical objects, each cell acting like a microscopic eyeball or the world’s oldest and smallest camera eye. Credit: eLife

Antibiotic resistance discovered in the guts of ancient mummies

The gut bacteria inside 1000-year-old mummies from the Inca Empire are resistant to most of today’s antibiotics, even though we only discovered these drugs within the last 100 years.

“At first we were very surprised,” Tasha Santiago-Rodriguez of California Polytechnic State University in San Louis Opisbo, told the Annual Meeting of the American Society for Microbiology last month.

Her team studied the DNA within the guts of three Incan mummies dating back to between the 10th and 14th centuries and six mummified people from Italy, from between the 15th and 18th centuries. They found an array of genes that have the potential to resist almost all modern antibiotics, including penicillin, vancomycin and tetracycline.

These ancient genes were largely in microbes whose resistance is problematic today, including Enteroccocus bacteria that can infect wounds and cause urinary tract infections. Read more.

sciencealert.com
Scientists just discovered plastic-eating bacteria that can break down PET
Bon appétit!
By Mark Lorch, The Conversation

[…]A team at Kyoto University has, by rummaging around in piles of waste, found a plastic munching microbe. After five years of searching through 250 samples, they isolated a bacteria that could live on poly(ethylene terephthalate) (PET), a common plastic used in bottles and clothing. They named the new species of bacteria Ideonella sakaiensis.

You may think this is the rerun of an old story, as plastic-eating microbes have already been touted as saviours of the planet. But there are several important differences here.

First, previous reports were of tricky-to-cultivate fungi, where in this case the microbe is easily grown. The researchers more or less left the PET in a warm jar with the bacterial culture and some other nutrients, and a few weeks later all the plastic was gone.

Second - and the real innovation - is that the team has identified the enzymes that Ideonella sakaiensis uses to breakdown the PET. All living things contain enzymes that they use to speed up necessary chemical reactions. Some enzymes help digest our food, dismantling it into useful building blocks. Without the necessary enzymes the body can’t access certain sources of food.

Continue Reading.

Scientists discover super bacteria in Rio waters

Earlier this year, medical ethicist Arthur Caplan wrote that it’s “senseless and irresponsible” to hold the 2016 Olympic Games in Rio de Janeiro in the midst of a spreading Zika crisis. The problem just got much worse: Only a month before the games begin, there’s now a drug-resistant “super-bacteria” growing on the city’s beaches. And it could even threaten athletes’ home countries.

Follow @the-future-now

CRISPR-like ‘immune’ system discovered in giant virus

Gigantic mimiviruses fend off invaders using defences similar to the CRISPR system deployed by bacteria and other microorganisms, French researchers report1. They say that the discovery of a working immune system in a mimivirus bolsters their claim that the giant virus represents a new branch in the tree of life.

Mimiviruses are so large that they are visible under a light microscope. Around half a micrometre across, and first found infecting amoebae living in a water tower, they boast genomes that are larger than those of some bacteria. They are distantly related to viruses that include smallpox, but unlike most viruses, they have genes to make amino acids, DNA letters and complex proteins.

That means that they blur the line between non-living viruses and living microbes, says Didier Raoult, a microbiologist at Aix-Marseille University in France, who co-led the study with microbiologist colleague Bernard La Scola. Raoult says that he doesn’t consider the mimivirus to be a typical virus; instead, it is more like a prokaryote — microbes, including bacteria, that lack nuclei.

Computer artwork of a particle of the giant mimivirus. Jose Antonio Penas/Science Photo Library

10

Selected works from Subvisual Subway by Craig Ward

Ward on his project:

Over the summer of 2015, I rode the trains of each of New York City’s twenty-two subway lines, collecting bacterial samples from hand rails, seats and other high traffic surfaces to create an unorthodox portrait of the city’s residents at the smallest of scales.

The samples were taken using sterilized sponges that had been pre-cut into the letter or number of the subway line from which the sample was to be taken - A, C, 1, 6 etc etc. The swabs were then pressed into pre-poured agar plates - their circular shape echoing the graphic language of the subway - and incubated for up to a week in his Brooklyn workshop, and photographed at various stages of development before being safely neutralized and disposed of.

The resulting images are a snapshot of the city’s constantly shifting ecosystem that each of us contribute to and are a part of. They hopefully also serve as a reminder that in a city that can make you feel small, there are countless billions of smaller inhabitants.

Cryoconite holes are bound together by bacteria

When wind borne particles settle on glaciers or ice sheets, they lower its albedo, and its ability to reflect heat back towards space rather than absorb it. The typical mixture (known as cryoconite) consists of dust, microbes, soot and ash, often carried from far off places, fires and factories. The darker dust absorbs more heat than the surrounding ice, and melts the frozen water around it, creating a mini melt lake with a dark layer of dust at the bottom.

Keep reading

This bacteria is killing people in the Midwest and the CDC can’t figure out why

On Monday, a total of 54 people across 12 counties in Wisconsin were reported to have been infected with a rare bacteria called Elizabethkingia, which already killed someone in Michigan on March 17. The outbreak is currently being investigated by the U.S. Centers for Disease Control and Prevention; general public knowledge of the bacteria is as virtually unknown as its origin. The antibiotic resistant bacteria is particularly deadly for one group of people.

Follow @the-future-now

Collective memory in bacteria

Individual bacterial cells have short memories. But groups of bacteria can develop a collective memory that can increase their tolerance to stress. This has been demonstrated experimentally for the first time in a study by Eawag and ETH Zurich scientists published in PNAS.

Roland Mathis, Martin Ackermann. Response of single bacterial cells to stress gives rise to complex history dependence at the population level. PNAS, March 7, 2016 DOI: 10.1073/pnas.1511509113

Experimental set-up with the bacterium Caulobacter crescentus in microfluidic chips: each chip comprises eight channels, with a bacterial population growing in each channel. The bacteria are attached to the glass surface by an adhesive stalk. When the bacterial cells divide, one of the two daughter cells remains in the channel, while the other is washed out. Using time-lapse microscopy, bacterial cell-division cycles and survival probabilities can thus be reconstructed. Credit: Stephanie Stutz

theatlantic.com
The Microbes That Eat Electricity
Energy-sucking bacteria on rocks beneath the planet’s surface may provide a blueprint for life on other worlds.
By Emily Singer

Last year, biophysicist Moh El-Naggar and his graduate student Yamini Jangir plunged beneath South Dakota’s Black Hills into an old gold mine that is now more famous as a home to a dark matter detector. Unlike most scientists who make pilgrimages to the Black Hills these days, El-Naggar and Jangir weren’t there to hunt for subatomic particles. They came in search of life.

In the darkness found a mile underground, the pair traversed the mine’s network of passages in search of a rusty metal pipe. They siphoned some of the pipe’s ancient water, directed it into a vessel, and inserted a variety of electrodes. They hoped the current would lure their prey, a little-studied microbe that can live off pure electricity.

Continue Reading.