New Worlds: Hydrogen output of algae boosted with genetic modification
"There may be other ways to produce hydrogen, but this is the greenest and the only agricultural one.”
By JUDY SIEGEL-ITZKOVICHLab technician using microscope(photo credit: INGIMAGE / ASAP)
Tel Aviv University researchers, using genetic engineering, have modified algae so it can be used to mass-produce hydrogen on an industrial scale. The team’s research appears in back-to-back studies published in Plant Physiology and Biotechnology for Biofuels.Hydrogen has the potential to be a clean and sustainable fuel, but realizing that potential relies on clean and sustainable methods to produce it. Algae might fit the bill, but it only produces hydrogen in small amounts.Hydrogen might burn clean, producing only water as a by-product, but currently over 90% of the hydrogen produced in the US comes from fossil fuels. Although algae can produce hydrogen using photosynthesis, it was believed that this only occurred for a few minutes at dawn, resulting in limited amounts of the gas.However, tests by a team led by Dr. Iftach Yacoby, head of TAU ’s renewable energy laboratory, have revealed that algae actually produces hydrogen throughout the day. Further tests revealed that the enzyme hydrogenase, which breaks down in the presence of oxygen, was integral to algae’s hydrogen production. Through genetic modification, the team members were able to remove the oxygen so the hydrogenase is able to keep producing hydrogen, resulting in a boost in hydrogen production of 400%.“The discovery of the mechanisms makes it clear that algae have a huge underutilized potential for the production of hydrogen fuel,” noted Yacoby. “The next question is how to beef up production for industrial purposes – to get the algae to overproduce the enzyme.”He is now hunting synthetic enzymes that can do just that. If the team succeed, algae could soon be pumping out mass quantities of the clean-burning fuel.“I grew up on a farm, dreaming of hydrogen,” he recalled. “Since the beginning of time, we have been using agriculture to make our own food. But when it comes to energy, we are still hunter-gatherers. Cultivating energy from agriculture is really the next revolution.There may be other ways to produce hydrogen, but this is the greenest and the only agricultural one.”MOVING EYES AND EARDRUMSSimply moving the eyes triggers the eardrums to move too, says a new study by neuroscientists at Duke University in North Carolina. The researchers found that keeping the head still but shifting the eyes to one side or the other sparks vibrations in the eardrums, even in the absence of any sounds.Surprisingly, these eardrum vibrations start slightly before the eyes move, indicating that motion in the ears and the eyes are controlled by the same motor commands deep within the brain. “It’s like the brain is saying, ‘I am going to move the eyes, so I’d better tell the eardrums, too,’” said psychology Prof. Jennifer Groh.The findings, which were replicated in both humans and rhesus monkeys, provide new insight into how the brain coordinates what we see and hear. It may also lead to new understanding of hearing disorders, such as difficulty following a conversation in a crowded room, they said.It’s no secret that the eyes and ears work together to make sense of the sights and sounds around us. Most people find it easier to understand somebody if they are looking at them and watching their lips move. In a famous illusion called the McGurk Effect, videos of lip cues dubbed with mismatched audio cause people to hear the wrong sound.Researchers are still puzzling over where and how the brain combines these two very different types of sensory information.“Our brains would like to match up what we see and what we hear according to where these stimuli are coming from, but the visual system and the auditory system figure out where stimuli are located in two completely different ways,” said Groh. “The eyes are giving you a camera-like snapshot of the visual scene, whereas for sounds, you have to calculate where they are coming from based on differences in timing and loudness across the two ears.”Because the eyes are usually darting about within the head, the visual and auditory worlds are constantly in flux with respect to one another, Groh added.Researchers asked 16 participants to sit in a dark room and follow shifting LED lights with their eyes.Each participant also wore small microphones in their ear canals that were sensitive enough to pick up the slight vibrations created when the eardrum sways back and forth.Though eardrums vibrate primarily in response to outside sounds, the brain can also control their movements using small bones in the middle ear and hair cells in the cochlea. These mechanisms help modulate the volume of sounds that ultimately reach the inner ear and brain, and produce small sounds known as otoacoustic emissions.It was found that when the eyes moved, both eardrums moved in sync with one another, one side bulging inward at the same time the other side bulged outward. They continued to vibrate back and forth together until shortly after the eyes stopped moving.Eye movements in opposite directions produced opposite patterns of vibrations. Larger eye movements also triggered bigger vibrations than smaller eye movements, the team found.“The eardrum movements literally contain information about what the eyes are doing,” Groh concluded.“This demonstrates that these two sensory pathways are coupled, and they are coupled at the earliest points.”
