Tag Archives: bacteria

Bacteria Frozen for 8 Million Years In Polar Ice Resuscitated

Eight-million-year-old bug is alive and growing

Kay Bidle of Rutgers University in New Jersey, US, and his colleagues extracted DNA and bacteria from ice found between 3 and 5 metres beneath the surface of a glacier in the Beacon and Mullins valleys of Antarctica. The ice gets older as it flows down the valleys and the researchers took five samples that were between 100,000 and 8 million years old.

They then attempted to resuscitate the organisms in the oldest and the youngest samples. “We tried to grow them in media, and the young stuff grew really fast. We could plate them and isolate colonies,” says Bidle. The cultures grown from organisms found in the 100,000-year-old ice doubled in size every 7 days on average.

Whereas the young ice contained a variety of microorganisms, the researchers found only one type of bacterium in the 8-million-year-old sample. It also grew in the laboratory but much more slowly, doubling only every 70 days.

Related: What is an Extremophile?

Tracking the Ecosystem Within Us

Gut Check: Tracking the Ecosystem Within Us

For more than 100 years, scientists have known that humans carry a rich ecosystem within their intestines. An astonishing number and variety of microbes, including as many as 400 species of bacteria, help humans digest food, mitigate disease, regulate fat storage, and even promote the formation of blood vessels. By applying sophisticated genetic analysis to samples of a year’s worth baby poop, Howard Hughes Medical Institute researchers have now developed a detailed picture of how these bacteria come and go in the intestinal tract during a child’s first year of life.
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Before birth, the human intestinal tract is sterile, but babies immediately begin to acquire the microbial denizens of the gut from their environment — the birth canal, mothers’ breast, and even the touch of a sibling or parent. Within days, a thriving microbial community is established and by adulthood, the human body typically has as many as ten times more microbial cells than human cells.
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The results, said Palmer, were striking: the group found that the intestinal microbial communities varied widely from baby to baby – both in terms of which microbes were present and in how that composition changed over time. That finding, she said, is important because it helps broaden the definition of healthy microbial colonization in a baby.

Another intriguing observation, Palmer noted, was a tendency for sudden shifts in the composition of the infants’ intestinal microbial communities over time as different species of bacteria ebbed and flowed.

I find this area and this study fascinating. I’m not exactly sure why this study and the incredibly significant positive bacteria for human life news doesn’t get more notice. Oh well I guess there are not cool pictures of robots or scary stories of potential threats to those reading which makes the news less interesting to some. Still I find this stuff amazing: Energy Efficiency of Digestion – Beneficial Bacteria – Skin Bacteria – Hacking Your Body’s Bacteria for Better Health – Where Bacteria Get Their Genes

Using Bacteria to Carry Nanoparticles Into Cells

Bacteria ferry nanoparticles into cells for early diagnosis, treatment

Researchers at Purdue University have shown that common bacteria can deliver a valuable cargo of “smart nanoparticles” into a cell to precisely position sensors, drugs or DNA for the early diagnosis and treatment of various diseases. The approach represents a potential way to overcome hurdles in delivering cargo to the interiors of cells, where they could be used as an alterative technology for gene therapy, said Rashid Bashir, a researcher at Purdue’s Birck Nanotechnology Center.

The researchers attached nanoparticles to the outside of bacteria and linked DNA to the nanoparticles. Then the nanoparticle-laden bacteria transported the DNA to the nuclei of cells, causing the cells to produce a fluorescent protein that glowed green. The same method could be used to deliver drugs, genes or other cargo into cells.

“The released cargo is designed to be transported to different locations in the cells to carry out disease detection and treatment simultaneously,” said Bashir, a professor in the Weldon School of Biomedical Engineering and the School of Electrical and Computer Engineering. “Because the bacteria and nanoparticle material can be selected from many choices, this is a delivery system that can be tailored to the characteristics of the receiving cells. It can deliver diagnostic or therapeutic cargo effectively for a wide range of needs.”

Harmless strains of bacteria could be used as vehicles, harnessing bacteria’s natural ability to penetrate cells and their nuclei, Bashir said. “For gene therapy, a big obstacle has been finding ways to transport the therapeutic DNA molecule through the nuclear membrane and into the nucleus,” he said. “Only when it is in the nucleus can the DNA produce proteins that perform specific functions and correct genetic disease conditions.”
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Evolution In Action

the way they watched the process was to sequence the whole genome of each bacterial isolate. What they found were a total of 35 mutations, which developed sequentially as the treatment continued (and the levels of resistance rose). Here’s natural selection, operating in real time, under the strongest magnifying glass available. And it’s in the service of a potentially serious problem, since resistant bacteria are no joke. (Reading between the lines of the PNAS abstract, for example, it appears that the patient involved in this study may well not have survived).

The technology involved here is worth thinking about. Even now, this was a rather costly experiment as these things go, and it’s worth a paper in a good journal. But a few years ago, needless to say, it would have been a borderline-insane idea, and a few years before that it would have been flatly impossible. A few years from now it’ll be routine, and a few years after that it probably won’t be done at all, having been superseded by something more elegant that no one’s come up with yet. But for now, we’re entering the age where wildly sequence-intensive experiments, many of which no one even bothered to think about before, will start to run.

Very interesting. He is exactly right that the technology advances continuing at an amazing pace allow for experiments we (at least I) can’t even imagine today to become common in just a few years. And the insights from those experiments will allow us to think of new experiments… Wonderful.

Disrupting the Replication of Bacteria

UW-Madison researchers develop novel method to find new antibiotics:

Filutowicz’s approach involves looking for new drugs that render bacteria harmless by blocking the replication of—and thus eliminating—some of their DNA.

Bacterial DNA comes in two forms: chromosomal DNA, which is required for life, and plasmid DNA, which is not. The nonessential plasmid DNA contains many undesirable bacterial genes, including those that confer antibiotic resistance or lead to the production of toxins.

Filutowicz is seeking antibiotics that would selectively disrupt the replication of plasmid DNA, so that when bacteria reproduce, they would produce plasmid-free offspring that are harmless or susceptible to traditional antibiotics. Such compounds could dramatically alter the character of some of our nastiest microbial adversaries.

Energy Efficiency of Digestion

Why is Fecal Matter Brown?

The complex digestion process ensures that almost no useful energy goes unused. The average bowel movement is three parts water to one part solid matter. Bacteria make up 30 percent of the solid stuff. The same goes for indigestible foods like cellulose and extra fiber. The remaining 40 percent contains various inorganic wastes, fats and used-up body substances like red blood cells

Scientists Examine 100 Trillion Microbes in Human Feces:

Aiding the large intestine in this task are trillions of microbes that reside in the gut, where they help digest foods we would otherwise have to avoid. In this way the bugs contribute to our overall health.

Some of these tiny settlers are with us from birth, imparted from our mothers, while others gradually colonize our bodies as we grow. This microbial community is as diverse as any found in Earth’s seas or soils, numbering up to 100 trillion individuals and representing more than 1,000 different species.

‘Virtually untreatable’ TB found

‘Virtually untreatable’ TB found:

TB presently causes about 1.7 million deaths a year worldwide, but researchers are worried about the emergence of strains that are resistant to drugs.

Drug resistance is caused by poor TB control, through taking the wrong types of drugs for the incorrect duration.

Multi-drug resistant TB (MDR TB), which describes strains of TB that are resistant to at least two of the main first-line TB drugs, is already a growing concern.

Globally, the WHO estimates there are about 425,000 cases of MDR TB a year, mostly occurring in the former Soviet Union, China and India.

How do antibiotics kill bacteria?

How do antibiotics kill bacterial cells but not human cells? (pointy haired bosses (phb) at Scientific American broke the link so I removed it – see links in comments below that are not broken by phb behavior)

Most bacteria produce a cell wall that is composed partly of a macromolecule called peptidoglycan, itself made up of amino sugars and short peptides. Human cells do not make or need peptidoglycan. Penicillin, one of the first antibiotics to be used widely, prevents the final cross-linking step, or transpeptidation, in assembly of this macromolecule. The result is a very fragile cell wall that bursts, killing the bacterium.

Read more blog posts on antibiotics and on health care.

Soil Could Shed Light on Antibiotic Resistance

Soil Could Shed Light on Antibiotic Resistance, Science Friday podcast (7 minutes) from NPR. The podcast is an interview with Gerry Wright, McMaster University, Canada.

“New research points to drug resistance in soil-dwelling bacteria. Scientists say studying bacteria in the soil can help in understanding how the bacteria in humans develop resistance.”

Posts relating to antibiotics
Overuse of anitbiotics articles
Curious Cat McMaster University Alumni Connections

Microbes

photo of T4 bacteriophage

Photo: T4 bacteriophage, middle, is a virus that invades bacterial cells. Courtesy of the MicrobeLibrary.org

The MicrobeWorld web site includes an introduction to microbes – Microbes: what they are and what they do:

Microbes are single-cell organisms so tiny that millions can fit into the eye of a needle.

They are the oldest form of life on earth. Microbe fossils date back more than 3.5 billion years to a time when the Earth was covered with oceans that regularly reached the boiling point, hundreds of millions of years before dinosaurs roamed the earth.

Microbes types:

Archaea
These bacteria look-alikes are living fossils that are providing clues to the earliest forms of life on Earth.

Bacteria
Often dismissed as “germs” that cause illness, bacteria help us do an amazing array of useful things, like make vitamins, break down some types of garbage, and maintain our atmosphere.

Fungi
From a single-celled yeast to a 3.5-mile-wide mushroom, fungi do everything from helping to bake bread to recycling to decomposing waste.

Protista
Plant-like algae produce much of the oxygen we breathe; animal-like protozoa (including the famous amoeba) help maintain the balance of microbial life.

Viruses
Unable to do much of anything on their own, viruses go into host cells to reproduce, often wreaking havoc and causing disease. Their ability to move genetic information from one cell to another makes them useful for cloning DNA and could provide a way to deliver gene therapy.