Cut and Paste Parasites are closer than we might wish. Harboured by mammals, cats in particular, Toxoplasma gondii could be encountered when cleaning the cat’s litter tray or by eating raw meat. These stowaways are only dangerous to those with weak immunity and unborn babies, but studying them can help reveal the secrets of their more threatening malaria-causing cousins. Toxoplasma cannot survive alone, invading and living inside cells of unsuspecting hosts. Their break-and-enter techniques include molecular grappling hooks, cell-piercing proteins and miniature propelling motors. Researchers created Toxoplasma containing DNA-crafting ‘scissors and glue’, known as recombinases, which cut out and replace certain genes. Successfully removing a motor in this way proved that Toxoplasma could invade without it. The group of motor-lacking Toxoplasma pictured are a normal shape; the remaining pink-stained invasion equipment is seen at their tips. Written by Claire Worrall — Markus Meissner University of Glasgow, UK Reprinted by permission from Macmillan Publishers Ltd: Nature Methods Copyright 2013 Published in Nature Methods 10: 125–127
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Cut and Paste

Parasites are closer than we might wish. Harboured by mammals, cats in particular, Toxoplasma gondii could be encountered when cleaning the cat’s litter tray or by eating raw meat. These stowaways are only dangerous to those with weak immunity and unborn babies, but studying them can help reveal the secrets of their more threatening malaria-causing cousins. Toxoplasma cannot survive alone, invading and living inside cells of unsuspecting hosts. Their break-and-enter techniques include molecular grappling hooks, cell-piercing proteins and miniature propelling motors. Researchers created Toxoplasma containing DNA-crafting ‘scissors and glue’, known as recombinases, which cut out and replace certain genes. Successfully removing a motor in this way proved that Toxoplasma could invade without it. The group of motor-lacking Toxoplasma pictured are a normal shape; the remaining pink-stained invasion equipment is seen at their tips.

Written by Claire Worrall

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Source: bpod.mrc.ac.uk

Neglected Deceivers To most invaders of our bodies, the sight of white blood cells (WBC) – the soldiers of our immune system – is bad news. However, despite having no limbs, the parasitic worm that causes the tropical disease, schistosomiasis, welcomes them with open arms. This is because only by piggy-backing on the immune response can the worm’s eggs pass from the host’s blood into the gut. From there they can be excreted and go on to infect other victims. Scientists have discovered that to get close to immune system activity, eggs gather in regions containing tubular pathways along which WBCs travel. In fact, eight weeks after infection (right image), these vessels (shown in red) are actually larger and more numerous than in animals naïve to the disease. By tricking the host’s own body to lend a hand to the worm, schistosomiasis, which damages internal organs, has already infected over 200 million people worldwide. Written by Jan Piotrowski — Adrian Mountford University of York, UK Originally published under a Creative Commons Attribution license Published in PLOS Pathogens 8(12): e1003063
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Neglected Deceivers

To most invaders of our bodies, the sight of white blood cells (WBC) – the soldiers of our immune system – is bad news. However, despite having no limbs, the parasitic worm that causes the tropical disease, schistosomiasis, welcomes them with open arms. This is because only by piggy-backing on the immune response can the worm’s eggs pass from the host’s blood into the gut. From there they can be excreted and go on to infect other victims. Scientists have discovered that to get close to immune system activity, eggs gather in regions containing tubular pathways along which WBCs travel. In fact, eight weeks after infection (right image), these vessels (shown in red) are actually larger and more numerous than in animals naïve to the disease. By tricking the host’s own body to lend a hand to the worm, schistosomiasis, which damages internal organs, has already infected over 200 million people worldwide.

Written by Jan Piotrowski

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Source: bpod.mrc.ac.uk

Vicious Circles A third of the world’s population has the parasite Toxoplasma gondii (T. gondii) living inside them. Infestation by these simple organisms (usually from eating infected meat) can cause serious problems during pregnancy. Here T. gondii has been genetically-modified to glow in a dish, allowing us to see how they might travel around inside our bodies. Their swirling traces were captured by microscope, similar to how a night-time video captures the trail of light from the tip of a sparkler. While it may look a little chaotic, this picture shows three distinct types of movement. The parasites (each cell is a white dot 400 times smaller than a glowing match head) are either spiralling, looping-the-loop, or twirling in star-like patterns. However pretty they are, watching these parasitic patterns could also guide the design of more effective drugs to stop future invasions in their elegant tracks. Written by John Ankers — James McCoy, Christopher Tonkin The Walter and Eliza Hall Institute of Medical Research, Australia Originally published under a Creative Commons Attribution license Published in PLOS Pathogens 8(12): e1003066
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Vicious Circles

A third of the world’s population has the parasite Toxoplasma gondii (T. gondii) living inside them. Infestation by these simple organisms (usually from eating infected meat) can cause serious problems during pregnancy. Here T. gondii has been genetically-modified to glow in a dish, allowing us to see how they might travel around inside our bodies. Their swirling traces were captured by microscope, similar to how a night-time video captures the trail of light from the tip of a sparkler. While it may look a little chaotic, this picture shows three distinct types of movement. The parasites (each cell is a white dot 400 times smaller than a glowing match head) are either spiralling, looping-the-loop, or twirling in star-like patterns. However pretty they are, watching these parasitic patterns could also guide the design of more effective drugs to stop future invasions in their elegant tracks.

Written by John Ankers

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Source: bpod.mrc.ac.uk

Iron Defence Ring The malaria parasite Plasmodium needs iron to survive. When it invades the animal host’s red blood cells the parasite hijacks iron from the red pigment (haemoglobin) within. In attempts to thwart the invasion, infected animals stockpile iron away from the parasite in their organs. But iron is toxic to cells, and iron overload causes tissue damage. Scientists keen to uncover why some people tolerate malaria disease, while many more die, are studying mice infected with Plasmodium. They’ve recently tracked down a key element – an iron detoxifying protein called Ferritin H chain (labelled red in infected mouse liver, right). Mice that tolerate malaria produce the protein when infected (uninfected liver shown on left; cells appear green and a large vein, black). Without the protein, infected mice suffer iron overload, develop organ failure and die. Scientists are now investigating whether humans use a similar strategy to protect themselves against this deadly disease. Written by Caroline Cross — Miguel Soares Instituto Gulbenkian de Ciência, Portugal Copyright Elsevier 2012 Published in Cell Host & Microbe 12(5): 693-704
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Iron Defence Ring

The malaria parasite Plasmodium needs iron to survive. When it invades the animal host’s red blood cells the parasite hijacks iron from the red pigment (haemoglobin) within. In attempts to thwart the invasion, infected animals stockpile iron away from the parasite in their organs. But iron is toxic to cells, and iron overload causes tissue damage. Scientists keen to uncover why some people tolerate malaria disease, while many more die, are studying mice infected with Plasmodium. They’ve recently tracked down a key element – an iron detoxifying protein called Ferritin H chain (labelled red in infected mouse liver, right). Mice that tolerate malaria produce the protein when infected (uninfected liver shown on left; cells appear green and a large vein, black). Without the protein, infected mice suffer iron overload, develop organ failure and die. Scientists are now investigating whether humans use a similar strategy to protect themselves against this deadly disease.

Written by Caroline Cross

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Published in Cell Host & Microbe 12(5): 693-704

Source: bpod.mrc.ac.uk

On the Run Life as a parasite is a constant race to evade host defences. For African trypanosomes (pictured) – responsible for diseases such as sleeping sickness – staying ahead means they have to keep moving. Each is a single cell with a long hair-like structure, or flagellum, anchored to the cell body and rotating to propel it through vertebrate bloodstreams, as shown here by 3D imaging. The host immune system detects threats using antibodies, molecules that recognise and bind to specific proteins on the surface of the parasite, marking it out for destruction. Rapid swimming generates a strong enough current to drag these antibodies to the base of the flagellum, where the cell can absorb them, thus allowing trypanosomes to go unnoticed. However, this swimming behaviour could ultimately be their downfall, as research into the mechanisms of trypanosome motion and its molecular underpinnings may reveal new targets for treatment. Written by Emmanuelle Briolat — Markus Engstler University of Würzburg, Germany Originally published under a Creative Commons Attribution license Published in PLOS Pathogens 8(11): e1003023
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On the Run

Life as a parasite is a constant race to evade host defences. For African trypanosomes (pictured) – responsible for diseases such as sleeping sickness – staying ahead means they have to keep moving. Each is a single cell with a long hair-like structure, or flagellum, anchored to the cell body and rotating to propel it through vertebrate bloodstreams, as shown here by 3D imaging. The host immune system detects threats using antibodies, molecules that recognise and bind to specific proteins on the surface of the parasite, marking it out for destruction. Rapid swimming generates a strong enough current to drag these antibodies to the base of the flagellum, where the cell can absorb them, thus allowing trypanosomes to go unnoticed. However, this swimming behaviour could ultimately be their downfall, as research into the mechanisms of trypanosome motion and its molecular underpinnings may reveal new targets for treatment.

Written by Emmanuelle Briolat

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Source: bpod.mrc.ac.uk

Worm Therapy? We all see the world differently, but for those with autism the world can be a particularly confusing jumble of people and places. Autism spectrum disorders affect one in a hundred children in the UK and there is no cure. Autistic individuals often have difficulties with social interaction, respond badly to change and display repetitive behaviours. It is speculated that some of these symptoms may be due to their immune systems over-reacting, causing chronic inflammation. So where do worms come in? The whipworm (pictured), specifically Trichuris suis, infects the intestines of both pigs and humans. Harmful and sometimes fatal to pigs, it is fairly innocuous to humans, and may even decrease inflammation. When an autistic boy was infected with whipworm eggs, he seemed to show improvement in his symptoms. This has spurred a small clinical trial to test if it might work for other people with autism. Written by Lux Fatimathas — Clinical trial information available here Images provided courtesy of Science Photo Library Copyright Science Photo Library Any re-use of this image must be authorised by Science Photo Library
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Worm Therapy?

We all see the world differently, but for those with autism the world can be a particularly confusing jumble of people and places. Autism spectrum disorders affect one in a hundred children in the UK and there is no cure. Autistic individuals often have difficulties with social interaction, respond badly to change and display repetitive behaviours. It is speculated that some of these symptoms may be due to their immune systems over-reacting, causing chronic inflammation. So where do worms come in? The whipworm (pictured), specifically Trichuris suis, infects the intestines of both pigs and humans. Harmful and sometimes fatal to pigs, it is fairly innocuous to humans, and may even decrease inflammation. When an autistic boy was infected with whipworm eggs, he seemed to show improvement in his symptoms. This has spurred a small clinical trial to test if it might work for other people with autism.

Written by Lux Fatimathas

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Source: bpod.mrc.ac.uk