Tag Archives | Microbiology

The Biology of Altruistic Suicide

Pic: Neon_JA (CC)

Pic: Neon_JA (CC)

Kanina Foss writing at the University of the Witwatersrand:

The question of why an individual would actively kill itself has been an evolutionary mystery. Death could hardly provide a fitness advantage to the dying individual. However, a new study has found that in single-celled algae, suicide benefits the organism’s relatives.

“Death can be altruistic – we showed that before – but now we know that programmed cell death benefits the organism’s relatives and not just anybody,” says Dr Pierre Durand from the Department of Molecular Medicine and Haematology and the Sydney Brenner Institute for Molecular Bioscience (SBIMB) at Wits University.

When Durand and his colleagues from the University of Arizona released the results of their first study on suicide in single-celled algae in 2011, they showed that when an organism commits suicide by digesting up its own body, it releases nutrients into the environment that can be used by other organisms.

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Six-Hundred Year-Old Petrified Poop Contains Antibiotic Resistance Genes

PIC: Dr. Graham Beards (PD)

PIC: Dr. Graham Beards (PD)

Once you get over the shock of a perfectly preserved 14th century turd (Dude, what did you eat?), the story is actually pretty interesting: Scientists examining a six hundred year-old piece of human poop have discovered the presence of genes that provide antibiotic resistance.

Via Heritage Daily:

A team of French investigators has discovered viruses containing genes for antibiotic resistance in a fossilized fecal sample from 14th century Belgium, long before antibiotics were used in medicine.

The viruses in the fecal sample are phages, which are viruses that infect bacteria, rather than infecting eukaryotic organisms such as animals, plants, and fungi. Most of the viral sequences the researchers found in the ancient coprolite (fossil fecal sample) were related to viruses currently known to infect bacteria commonly found in stools (and hence, in the human gastrointestinal tract), including both bacteria that live harmlessly, and even helpfully in the human gut, and human pathogens, says corresponding author Christelle Desnues of Aix Marseille Université.

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A New Evolutionary Theory: The Black Queen Hypothesis

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Photo: Liko81 (CC)

Via ScienceDaily:

Microorganisms can sometimes lose the ability to perform a function that appears to be necessary for their survival, and yet they still somehow manage to endure and multiply. How can this be? The authors of an opinion piece appearing in mBio, the online open-access journal of the American Society for Microbiology, on March 27 explain their ideas about the matter. They say microbes that shed necessary functions are getting others to do the hard work for them, an adaptation that can encourage microorganisms to live in cooperative communities.

The Black Queen Hypothesis, as they call it, puts forth the idea that some of the needs of microorganisms can be met by other organisms, enabling microbes that rely on one another to live more efficiently by paring down the genes they have to carry around. In these cases, it would make evolutionary sense for a microbe to lose a burdensome gene for a function it doesn’t have to perform for itself.

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NASA Finds New Life Form, Made of Arsenic, in the Poisonous Mono Lake

BacteriaNew life-forms! Right here on Planet Earth! Jesus Diaz writes on WIRED Science:

Hours before their special news conference today, the cat is out of the bag: NASA has discovered a completely new life form that doesn’t share the biological building blocks of anything currently living in planet Earth. This changes everything.

At their conference today, NASA scientist Felisa Wolfe Simon will announce that they have found a bacteria whose DNA is completely alien to what we know today. Instead of using phosphorus, the bacteria uses arsenic. All life on Earth is made of six components: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. Every being, from the smallest amoeba to the largest whale, share the same life stream. Our DNA blocks are all the same.

But not this one. This one is completely different. Discovered in the poisonous Mono Lake, California, this bacteria is made of arsenic, something that was thought to be completely impossible.

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Are Bacteria Far More Intelligent Than We Realize?

mmw_prokaryote_1110Bacteria can distinguish “self” from “other,” and between their relatives and strangers. They can communicate, prey in packs, and have social intelligence. Are microbes far more sentient than we give them credit for? Miller-McCune writes:

Strictly by the numbers, the vast majority — estimated by many scientists at 90 percent — of the cells in what you think of as your body are actually bacteria, not human cells. In fact, most of the life on the planet is probably composed of bacteria.

These facts by themselves may trigger existential shock: People are partly made of pond scum. But beyond that psychic trauma, a new and astonishing vista unfolds. In a series of recent findings, researchers describe bacteria that communicate in sophisticated ways, take concerted action, influence human physiology, alter human thinking and work together to bioengineer the environment. These findings may foreshadow new medical procedures that encourage bacterial participation in human health.

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Check Out Antarctica’s ‘Blood Falls’

Creepy and cool. Annalee Newitz writes on io9.com:

From a crack in the Taylor Glacier in Antarctica flows an iron-rich water the color of blood. Scientists believe it comes from a lake frozen beneath the glacier 2 million years ago. And it’s packed with microbes.

First discovered in 1911, the so-called Blood Falls also contain extremophile microbes from the trapped lake, which have evolved for millions of years without light or any outside food source. They have survived by learning to eat sulfur and iron.

Blood Falls

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