Bacterial heroes

Charitable bacteria protect vulnerable sisters from antibiotics

Humans are capable of great charity, taking hits to their bank accounts and bodies to benefit their peers. But such acts of altruism aren’t limited to us; they can be found in the simple colonies of bacteria too.

Bacteria are famed for their ability to adapt to our toughest antibiotics. But resistance doesn’t spring up evenly across an entire colony. A new study suggests that a small cadre of hero bacteria are responsible for saving their peers. By shouldering the burden of resistance at a personal cost, these charitable cells ensure that the entire colony survives…

much more via Not Exactly Rocket Science

Arctic Fish and Cellular Antifreeze

Scientists studying why fish in the Arctic ocean don’t freeze have discovered how a natural antifreeze that keeps blood flowing at sub-zero temperatures works.

excerpt is from Wired Science

The temperature of the water in the Arctic is a fairly constant 28.6 degrees Fahrenheit year-round, close to the freezing point of seawater. The freezing point of fish blood, however, is about 30.4 degrees Fahrenheit. You’d expect fish traveling beyond a certain latitude to ice up.

Instead, fish are able to keep moving thanks to a frost-protection protein in their blood. It was discovered about 50 years ago, but only now are scientists discovering how the protein works.

Researchers led by Bochum University chemist Martina Havenith used terahertz spectroscopy to examine water molecules in the presence of the protein. They saw that water molecules, which normally dance around, forming and breaking bonds, slow down in the protein’s vicinity.

Read More via Why Fish In the Arctic Don’t Freeze

Ants use bacteria to create antibiotics

ScienceDaily (Aug. 26, 2010) — Research led by Dr Matt Hutchings and published today in the journal BMC Biology shows that ants use the antibiotics to inhibit the growth of unwanted fungi and bacteria in their fungus cultures which they use to feed their larvae and queen.

These antibiotics are produced by actinomycete bacteria that live on the ants in a mutual symbiosis.

Although these ants have been studied for more than 100 years this is the first demonstration that a single ant colony uses multiple antibiotics and is reminiscent of the use of multidrug therapy to treat infections in humans…

more via Ants Use Multiple Antibiotics As Weed Killers

Antidepressant residuals and crustaceans

from Deep Sea News
ON JULY 19TH, 2010

Figure 2 from paper: Mean average phototaxis and geotaxis score of E. marinus exposed to varied concentrations of serotonin (n = 20 per treatment) over a 3-week period. Error bars to one standard deviation. *Significance compared with control determined by Mann–Whitney and Bonferroni correction p < 0.0125.

Nearly 30-90% of the pharmaceuticals we digest are excreted in its active form. These active pharmaceuticals collect sewage systems and eventually make their way to streams, rivers, lakes, and oceans. What are the effects of these pharmaceuticals on aquatic and marine organisms? In a recent study, scientists exposed crustaceans, the amphipodEchinogammarus marinus, common in the freshwaters of Portugal to multiple drugs. Amphipods demonstrated increased response to light (phototaxis) and gravity (geotaxis) when exposed to serotonin.

Fig. 1 from paper. Mean average phototaxis and geotaxis score of E. marinus with acanthocephalan infection and a non-infected control group (n = 20 per treatment). Error bars to one standard deviation.*Significance compared with control(p < 0.05).

The Acanthocephala parasite Rhadinorhynchus. I don’t care if that big predator is heading my way…I’m just soo damn happy. Image from Wikimedia Commons

Echinogammarus says “I am going to the big light”

As background, serotonin is the neurotransomiter that produces that happy feeling and serves to regulate our moods by aiding with sleep and reducing anxiety and depression. Interestingly, certain parasites are known to increasing swimming behavior in amphipods through increasing serotonin levels. Amphipods with parasite loads also exhibited increased photo- and geotaxis.

All this “extra” swimming makes the amphipods stand out to predators.

Take home message: Our use of antidepressants kill off that little guy to right and generally alter the ecological interactions of organisms in the water.

Guler, Y., & Ford, A. (2010). Anti-depressants make amphipods see the light Aquatic Toxicology DOI: 10.1016/j.aquatox.2010.05.019

originally published via Your Happiness Kills Crustaceans

With a little help from my… bacteria

excerpt is from the blog Cunabulum

…Less frequently realized is a bacterial relationship of another kind: symbiosis. Perhaps by now, more than 40 years after Lynn Margulis‘ stunning work popularizing it, the endosymbiotic theory of the origins of many organelles within the eukaryotic cell, including mitochondria and chloroplasts, is widely understood enough to continue without comment. But briefly, there is a heap of undeniable evidence that many of the eukaryote’s organelles were once free-living bacteria that were engulfed and put to work by other cells: mitochondria respire, chloroplasts photosynthesize. It is reasonable to assume other such relationships exist within certain lineages of eukaryotes.

So here we have leafhoppers, like many other insects including aphids, feed almost exclusively on the phloem or xylem fluid of plants. With such a restricted diet, you are bound to run into nutritional deficiencies. Syrup is tasty, but I wouldn’t want to subsist solely on it! What’s an insect to do? The clear answer is to harvest those little nutrient-producing biological machines known as bacteria…

more via Endosymbiotic Bacteria in Leafhoppers

Yeast, fish and us

from NPR

…”It’s like peeling an onion,” he says. “Layer after layer after layer is revealed to you. Like in a human body, the first layer is our primate history, the second layer is our mammal history, and on and on and on and on, until you get to the fundamental molecular and cellular machinery that makes our bodies and keeps are cells alive, and so forth.”

Our Inner Yeast

In fact, not only are we related to an ancient fish, but many of the parts critical for making yeast are also critical for making us, says Gavin Sherlock, a geneticist at Stanford University.

“About one-third of the yeast genes have a direct equivalent version that still exists in humans,” he says.

Sherlock says that not only do many of the same genes still exist in humans and yeast, but they’re so similar that you can exchange one for the other.

“There are several hundred examples where you can knock out the yeast gene, put in the human equivalent, and it restores it back to normal,” he says.

Think about it, he says: We have a lot in common with yeast. Yeast consume sugars like we do, yeast make hormones like we do, and yeast have sex — not quite like we do, but sex…

more via Finding our inner fish

I am he, as you are me and we are all together

Some of our most important relations are microbial. In fact, sometimes the relationship is so close that we become one.

Here is a piece from the Lab Rat Blog

Although bacteria are often thought of as invading pathogens, not all bacterial interactions are necessarily to the detriment of the host. Some bacteria are able to establish mutualistic relationships which benefit both the bacteria and the organism in which it lives. An example can be seen in legumes, which have bacteria in specialised root nodules which carry out nitrogen fixation. The plant gains a source of nitrogen while the bacterium gains a safe space to live and a good source of carbohydrates.Root of a legume, showing the bumpy nodules where the bacteria live

Studies of how bacteria evolve from free-living organisms into mutualistic partners of eukaryotic (i.e not bacterial) cells has been made easier with the availability of large numbers of sequenced genomes. Intracellular bacteria in general tend to have a smaller genome than free-living bacteria as they have fewer changing environmental conditions to respond too, and many of their metabolic needs can be met by their host. Examining bacteria within their natural environment (rather than the very specific and controlled laboratory environment) also helps to identify the selective forces that can act on bacteria to drive them towards adaptations for mutualistic living.

In order to adapt to a mutualistic lifestyle the bacteria must also gain new genes, which produce proteins that allow it to invade, and communicate with, its host. Genes involved in host interactions are often found in genomic islands, or near to mobile elements which are able to move the genes between organisms (particularly bacteriophages – virus’s that invade bacteria). It has been suggested that the ability of these mobile elements to leave one bacteria and invade neighbouring ones can help to prevent bacterial ‘cheaters’ i.e those that reap the benefits of the mutualistic relationship while relying on the surrounding bacteria to produce the necessary proteins.

Although several species have been found that are thought to have moved from being mutual partners to free-living, the reduction in genome size and host dependency means that once a relationship with the host is established, it tends to remain (occasionally breaking down into parasitism)…

more via The Evolution of Mutualistic Relationships

The Russian Fox Study

from the blog The Thoughtful Animal

In 1948, Soviet scientist Dmitri Belyaev lost his job at the Department of Fur Animal Breeding at the Central Research Laboratory of Fur Breeding in Moscow because of his commitment to classical genetics. At the time, in Soviet Russia, Lysenkoism was all the rage (and by that, I mean, it was state doctrine). Lysenkoism (named for its champion Trofim Lysenko) is akin to Lamarckian inheritance – than acquired characteristics could be passed down to offspring. We now know, of course, that Lamarck was basically wrong and an organism’s experiences can not be genetically passed to its offspring (though there may be other mechanisms).

Our hero Belyaev was kicked out of the Fur Breeding Lab in Moscow, but he continued to study genetics under the guise of studying animal physiology throughout the 1950s. Then, in 1959, he became the director of the Institute of Cytology and Genetics of the Russian Academy of Sciences, in Novosibirsk, Russia. He remained director through 1985.

At the time, biologists were puzzled as to how dogs evolved to have different coats than wolves, since they couldn’t figure out how the dogs could have inherited those genes from their ancestors. Belyaev saw silver foxes as a perfect opportunity to find out how this happened.

Belyaev believed that the key factor that was selected for was not morphological (physical attributes), but was behavioral. More specifically, he believed that tameness was the critical factor. How amenable was an animal to interacting with humans? This would certainly impact how well an animal would adapt to life with humans.

Figure 1: Dmitry Belyaev with some of his domesticated silver foxes, in 1984.

He hypothesized that selecting for tameness and against aggression would result in hormonal and neurochemical changes, since behavior was ultimately rooted in biology. It could be that the genetic differences that led to the morphological changes that biologists noticed in domesticated dogs (particularly, they noticed differences in fur coloration, and increased skull size relative to body size) were related to the genetic changes that underlied the behavioral temperament that they selected for (tameness and low aggression). He believed that he could investigate some of the questions about domestication by attempting to domesticate wild foxes. Belyaev and his colleagues took wild silver foxes (a variant of the red fox) and bred them, with a strong selection for inherent tameness…

much much more via The Thoughtful Animal blog

Bacterial magnetosomes

from the blog Thoughtonomics:

Magnetosomes are little membrane bound particles which are found in certain bacteria. These particles contain magnetite crystals which, as well as making them sound like very small X-men, allow the bacteria to line up in the direction of the earth’s geomagnetic field, essentially acting like a compass. Why this is helpfully is not entirely certain, but it may give help to give the bacteria a sense of direction while searching for a suitable environment in which to live.

These particles tend to line up on one side of the bacteria to form a long chain of individually membrane wrapped particles, as shown in the figure below:

One of the potentially most interesting things about these magnetic particles is that they are held in organelle type structures, surrounded by a membrane. Organelles are little sub-cellular structures that are usually found in eukaryotes, ( i.e the nucleus, mitochondria, Golgi apparatus etc.) Finding these inside bacteria is interesting, as it shows that bacteria can contain organelle-type structures within them, giving them intracellular organisation despite their small size. …

for the rest of the post go to Lab Rat at Thoughtonomics

Whipworms and bacteria: interdependence illustrated

Study suggests new way to battle common intestinal infection
By Rachel Ehrenberg
Web edition : 1:37 pm
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EGGED ONBacteria (tiny flecks) swarm around the eggs of intestinal whipworms, alerting the parasites that they are in a good place to hatch.Kelly Hayes, University of Manchester

The question of which came first, the whipworm or the whipworm egg, leaves out a key player: bacteria.

Eggs of the parasitic whipworm, whose potential hosts include humans, won’t hatch in their host’s intestine until they get the go-ahead from nearby gut bacteria, researchers report June 10 in Science.

The work reveals how the parasite avoids hatching in the wrong place. It also highlights that parasite-host interactions don’t occur in isolation.

“This is a very nice illustration of the interdependence of things,” says Rick Maizels, an immunologist at the University of Edinburgh in Scotland who was not involved in the work. The finding also suggests a means of stymieing whipworm infection, Maizels says, as interrupting the bacterial message could prevent whipworm eggs from hatching….

more via Science News