If we can’t see landmarks, we really do end up walking in circles. That’s the conclusion of researchers who have tracked people trying to cross pathless deserts and forests.

of the Max Planck Institute for Biological Cybernetics in TĂĽbingen, Germany, spends his days researching how the human brain combines information from the senses to build up a picture of the world around it.

When he was approached by a German television station that wanted to track people lost in the Sahara desert for a programme about human navigation, he thought the idea was pretty cool. Together they set about investigating the popular belief that people who are lost often find themselves walking in circles.

Souman and his team took volunteers into a forest and the Sahara, fitted them with a GPS tracker and asked them to walk on a straight course through the unfamiliar terrain. When the sun was out participants managed this surprisingly well, but on cloudy days or at night, with no visual cues to guide them, they veered away, often walking in circles.

“I didn’t believe that people really would walk in circles, so I was quite surprised,” says Souman.

Legging it

This is the first research to investigate whether lost people do unknowingly walk in circles. Several explanations for the idea have been suggested in the past, however, including physical differences between one side of the body and the other.

Souman’s team investigated this idea in a second experiment. Participants had their leg strengths measured or had the sole of one shoe made thicker to reproduce the effect of unequal leg lengths. They were then blindfolded and asked to walk a straight line in a large, disused airfield.

By depriving people of sight the researchers hoped that any inclination to move to one side or the other would be enhanced. But this didn’t happen: from test to test, most people changed the direction in which they strayed, showing that the human tendency to veer off course is not a result of physical asymmetry.

The paper proposes that the real reason for our inability to walk in a straight line without landmarks is likely to be accumulating errors in judging a straight path. Allen Cheung at the University of Queensland in Brisbane, Australia, who was not involved in the work, agrees: “Although each turn angle may be small and so go unnoticed, if it is not corrected, it will add up.”

Virtual stroll

Only a small number of people took part in the experiments, which limited their usefulness, but the team hope to overcome this soon. They have developed a treadmill that moves in all directions; when combined with a screen, it should allow participants to freely explore a virtual landscape. This will enable researchers to collect more results than was possible with the outdoor experiments.

“Another thing we found intriguing was that despite the sun moving in the sky throughout the experiment, when it was visible people walked in a remarkably straight line,” said Souman. “This suggests that they were effectively accounting for its movement.” Using their virtual set-up, Souman and his team would like to look into this further.

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Venter’s team took the genome of one bacterium, Mycoplasma mycoides, copied and modified it in yeast, and then transplanted it into another bacterial species, M. capricolum.

At first the transplant didn’t work. When the modified genome was inserted into the recipient cell it was immediately recognised and degraded.

The team tried two methods to overcome the problem. First, they sought out and deactivated the enzyme in M. capricolum capable of recognising and damaging the foreign DNA.

Non-recognition

Then they attempted to disguise the donor DNA in order to trick the recipient species into believing the genome had always belonged in the cell. They found that the most reliable transplant solution was to hijack the recipient cell’s recognition enzymes and stop them from working.

“The new [transplant] cycle developed has never existed before in molecular biology,” says Venter, who describes the work as “mastering the tools to move genomes across the branches of life.”

Bacterial genomes are notoriously difficult to modify, and using transfer into yeast as an intermediate step allows scientists to use a much wider range of genetic tools for tweaking the genome.

, a biomedical engineer from Boston University not involved in the study, is interested in how the research expands the capabilities of genetic engineering. “This is a marvellous advance which provides us with a straightforward way to make larger-scale changes to bacterial organisms which were not possible before,” he says.

Synthetic life stirs

This most recent work edges Venter one step closer to creating synthetic life. He has already shown that genomes can be built from scratch, by taking the gene sequence of the bacterium Mycoplasma genitalium and constructing it in the lab.

The next step will be to insert a lab-built genome into a bacterial cell, creating a brand new living organism. Avoiding recognition and destruction will be a very important part of this process.

If the ability to build a synthetic genome can be combined with this technique to transplant it, then the dawn of synthetic life could be close. Indeed Venter hopes this biological milestone will be possible in just a month or so.

Venter’s quest for synthetic life ultimately aims to create purpose-built organisms that can carry out specific roles, such as producing biofuels or even making hydrogen.

“The advantage of synthetic DNA is that it allows even more radical changes than an engineered genome,” says geneticist of Harvard Medical School. “The key advances in this paper seem to be the transfer of DNA derived from Mycoplasma from yeast into a different Mycoplasma ˛őłŮ°ů˛ąľ±˛Ô.”

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In the depths of the Pacific Ocean, newly discovered species of free-swimming worms have a unique method of distracting predators. They deploy “bombs” that burst in a flare of green light.

The annelid worms, which live between 1800 and 3800 metres below the waves, have been discovered by a team led by of the Scripps Institute of Oceanography in San Diego, California. “I first got interested because these were not like any worms I had ever seen before,” said Osborn.

The worms have elliptically shaped organs at their front end, about 1 to 2 millimetres in size. When captured worms were examined in the lab, Osborn noticed the organs being ejected into the water, where they started shining brightly for several seconds before slowly dying away.

Bioluminescence is common in the deep sea and is used by creatures for a range of purposes, including avoiding predators, communication and attracting prey. Osborn thinks her worms use their glow bombs to distract predators while they make an escape.

“It’s really exciting to have found this whole unknown group, and it shows that there is so much we have still to learn,” she says.

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Compounds similar to those found in cannabis have been shown to stop prostate cancer cells from multiplying. Two cannabinoid compounds, JWH-015 and MET, stopped prostate tumour growth in human prostate cells in Petri dishes and also in mice with the disease. They halted the cell-division cycle and killed the cancer cells, and had the greatest effect on aggressive prostate cancer cell types, which do not respond to hormone treatments.

Some 192,000 men in the US alone are diagnosed with prostate cancer each year, and researchers at the University of Alcalá, Spain, and her colleagues say the results could offer hope to those affected. But before you go looking for a dealer, żěè¶ĚĘÓƵ answers a few questions.

Does this mean that smoking dope can protect against prostate cancer?

No. The findings do not imply that smoking cannabis can prevent or treat prostate cancer. Even aside from the harm to health that is associated with dope smoking, the cannabinoid compounds that this study tested are synthetic chemicals not found in cannabis plants, so no conclusions about the actual stuff can be drawn.

So if I shouldn’t smoke cannabis to fight cancer, how can I use cannabinoids?

The chemicals that have been tested could eventually be used to develop prostate cancer treatments. These treatments would not be the same as cannabis – they would simply contain cannabis-like chemicals as the active ingredients.

Would cannabis-derived drugs make patients feel stoned?

No. No drug developed from these compounds would affect the mind as cannabis use does. There are two types of receptor in the prostate to which cannabinoid compounds can attach. Both types are found in the brain but only one is associated with the psychotropic effects of using cannabis. DĂ­az-Laviada Marturet’s research looked specifically at cannabinoid compounds that attach to the CB₂ receptor – the one not associated with psychotropic effects.

Haven’t cannabis chemicals already been found to protect against cancer?

There is a long list of cancers for which cannabinoids are thought to have a therapeutic benefit. This list includes , lung and colon cancer.

So when will we see cannabis-derived anti-cancer drugs on the market?

Prostate cancer treatments based on these cannabis chemicals are still a long way from clinical trial. The chemicals tested have been shown to be effective both in cell cultures and in mice, but a lot more needs to be found out about these chemicals before anti-cancer drugs can be developed.

advises a healthy diet and lifestyle and recommends that as the symptoms of prostate cancer and other prostate problems can be similar, it is important to get a proper diagnosis because other treatments are already available.

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Picture a thick wedge of rich, velvety Black Forest gateau. Hungry? Unlikely as it sounds, showing weight-conscious women pictures of sweet treats actually strengthens their resolve to eat healthily, rather than encouraging them to cheat.

Advertisers clearly believe images of tasty morsels persuade people to buy but psychologist of Utrecht University in the Netherlands speculated that temptation might in fact heighten self-control.

To test out this theory, Kroese and her colleagues asked 54 female students to look at a picture of either a slice of chocolate cake or a flower under the guise of a memory test. The researchers then questioned the students about any plans to eat more healthily and offered them a choice between a chocolate or oatmeal cookie.

Women shown the cake picture gave a higher priority to their healthy eating intentions than their counterparts shown the flower. They were also significantly more likely to pick the oatmeal cookie – which earlier tests showed was generally perceived as the healthier option.

Let them look at cake

“Food temptations do not always trigger indulgence,” says Kroese. “It seems that seeing a food temptation reminded people of their goal to watch their weight, and helped them act accordingly.”

Previous studies suggested that smelling palatable, unhealthy foods makes people rate healthy eating as highly important, but this is the first research to look at how unhealthy food affects snacking behaviour.

of the Booth School of Business at the University of Chicago agrees with Kroese’s conclusion. “In moderation, this positive impact of food temptations will overcome the negative impact – the urge to indulge,” she says.

Kroese suggests that sticking pictures of tempting foods on the fridge door may help to bring weight-watching goals to mind. But she cautions that the results can only be applied to women wanting to lose weight: it is unclear whether they would hold in the general population.

Her team is now looking into varying the strength of a temptation. Early findings suggest that while very tempting images seem to remind people of their weight-loss goals, weakly attractive images do not prompt the same mechanism to kick in. “Interestingly, this might mean that weak temptations could then be more dangerous,” she says.

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