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It's a hobbit… no, it's a human… no, it's a hobbit
In brief– Clues to disease in It’s a hobbit… no, it’s a human… no, it’s a hobbit stink bug baby food
TAKAHIRO HOSOKAWA
18 | NewScientist | 14 October 2006
THE battle over the “hobbit” that lived 18,000 years ago on the Indonesian island of Flores is taking on epic proportions worthy of The Lord of the Rings. On one side is Robert Martin of the Field Museum of Natural History in Chicago, who says the existence of a species of smallbrained dwarf human is a fantasy. Instead, he argues, the fossil is merely a stone-age human with a mild form of microcephaly, a disease which stunts brain development and is associated with small stature. And he says the stone tools found at the site
were made by regular Homo sapiens (Anatomical Record, DOI: 10.1002/ar.a.20394). Recently, however, Colin Groves of the Australian National University, Canberra, argued that Homo floresiensis has the wrong shape of skull for a human with microcephaly and is therefore a separate species (Journal of Human Evolution, vol 51, p 360). “There’s no sign of anything but H. floresiensis on Flores at the end of the Pleistocene,” he says. Dean Falk of Florida State University, Tallahassee, seems to agree – according to her research
the skull lacks features shared by 10 modern humans with microcephaly. “The brain is a combination of features I’ve never seen in any other primate.” Further studies of the fossil are unlikely to resolve the argument without new material, says Chris Stringer of the Natural History Museum in London. “We need a second skull to see what the variation is.” Only then will we know if the hobbit with the chimp-sized brain was one of a kind or belonged to an unexpected branch of the human tree.
Maggots, just what the doctor ordered
Closer analysis revealed that protease enzymes in the juice caused specialised repair cells to move more swiftly and freely to the wound site. “They all march in unison and fill the hole significantly quicker,” says co-author David Pritchard of the University of Nottingham. The team now hopes to produce wound dressings impregnated with purified maggot extracts, which would protect the wound and speed up healing without the yuck factor of the maggots. “You could get the benefits without the insects themselves,” says Britland. They have already created a prototype gel which healed wounds just as quickly as applying the maggot extracts directly.
SUKREE SUKPLANG/REUTERS
HOLD your nose. The contents of the humble stink bug’s gut might help explain how disease-causing bacteria originate. Along with their eggs, plataspid stink bugs lay a packet of gut bacteria which the nymphs eat. As the nymphs develop, their guts divide: the top becomes a blind sac for digesting plant juice, while the bottom end swells into a fermentation chamber where the bacteria provide the stink bugs with vital nutrients. Takema Fukatsu and colleagues at the Institute of Advanced Industrial Science and Technology in Tsukuba, Japan, constructed a DNA family tree of the bacteria species found in different stink bug species to show how the bacteria were related. To their surprise, the tree was identical to one for the stink bugs themselves, showing that bacteria and insects had evolved in lockstep (PLoS Biology, DOI: 10.1371/journal.pbio.0040337). This was completely unexpected for bacteria living free in an insect’s gut. Moreover, the bacteria have the same shrunken genomes and other changes seen in disease bacteria such as chlamydia. The team thinks these changes reflect the way bacteria adapt to a host, whether as helpers or as parasites. “This is likely to provide insights into the evolution of bacterial pathogens,” Fukatsu says. The way the plataspids deliver capsules of bacteria to their eggs will allow researchers to investigate this further by manipulating the host and bacteria separately.
Wobble killed off mammal species MAMMALIAN species are known to last an average of 2.5 million years before being snuffed out, but nobody had been able to figure out why. The reason, it turns out, may be linked to regular wobbles in Earth’s orbit. Jan van Dam from Utrecht University in the Netherlands and colleagues reached this conclusion after studying the fossil record of rodents from central Spain over a 22-millionyear span. This showed a link between rodent extinction events and the climate record. Changes in the Earth’s tilt and the shape of its orbit lead to climate cycles of around 1.2 and 2.4 million years. At their extremes both these cycles cause global cooling, expansion of polar ice sheets and changes in rainfall patterns. The extinction peaks coincided with global cooling maxima, while new appearance peaks coincided with periods of stable climate (Nature, DOI: 10.1038/nature05163). “Changes in seasonality associated with the astronomical variations – harsh winters, dry summers – are really a matter of life and death to mammals,” van Dam points out.
IT’S not a treatment for the fainthearted. Now it seems that not only do maggots eat away the dead tissue from wounds and allow healing to begin, they also secrete a fluid containing enzymes to speed up the healing process. Stephen Britland at the University of Bradford, UK, and his colleagues applied extracts of maggot juice to layers of cells that mimic skin. When circular “wounds” were created in the cell layers, those exposed to the maggot extracts healed fastest (Biotechnology Progress, DOI: 10.1021/ bp0601600).
www.newscientist.com
TAKAHIRO HOSOKAWA
18 | NewScientist | 14 October 2006
THE battle over the “hobbit” that lived 18,000 years ago on the Indonesian island of Flores is taking on epic proportions worthy of The Lord of the Rings. On one side is Robert Martin of the Field Museum of Natural History in Chicago, who says the existence of a species of smallbrained dwarf human is a fantasy. Instead, he argues, the fossil is merely a stone-age human with a mild form of microcephaly, a disease which stunts brain development and is associated with small stature. And he says the stone tools found at the site
were made by regular Homo sapiens (Anatomical Record, DOI: 10.1002/ar.a.20394). Recently, however, Colin Groves of the Australian National University, Canberra, argued that Homo floresiensis has the wrong shape of skull for a human with microcephaly and is therefore a separate species (Journal of Human Evolution, vol 51, p 360). “There’s no sign of anything but H. floresiensis on Flores at the end of the Pleistocene,” he says. Dean Falk of Florida State University, Tallahassee, seems to agree – according to her research
the skull lacks features shared by 10 modern humans with microcephaly. “The brain is a combination of features I’ve never seen in any other primate.” Further studies of the fossil are unlikely to resolve the argument without new material, says Chris Stringer of the Natural History Museum in London. “We need a second skull to see what the variation is.” Only then will we know if the hobbit with the chimp-sized brain was one of a kind or belonged to an unexpected branch of the human tree.
Maggots, just what the doctor ordered
Closer analysis revealed that protease enzymes in the juice caused specialised repair cells to move more swiftly and freely to the wound site. “They all march in unison and fill the hole significantly quicker,” says co-author David Pritchard of the University of Nottingham. The team now hopes to produce wound dressings impregnated with purified maggot extracts, which would protect the wound and speed up healing without the yuck factor of the maggots. “You could get the benefits without the insects themselves,” says Britland. They have already created a prototype gel which healed wounds just as quickly as applying the maggot extracts directly.
SUKREE SUKPLANG/REUTERS
HOLD your nose. The contents of the humble stink bug’s gut might help explain how disease-causing bacteria originate. Along with their eggs, plataspid stink bugs lay a packet of gut bacteria which the nymphs eat. As the nymphs develop, their guts divide: the top becomes a blind sac for digesting plant juice, while the bottom end swells into a fermentation chamber where the bacteria provide the stink bugs with vital nutrients. Takema Fukatsu and colleagues at the Institute of Advanced Industrial Science and Technology in Tsukuba, Japan, constructed a DNA family tree of the bacteria species found in different stink bug species to show how the bacteria were related. To their surprise, the tree was identical to one for the stink bugs themselves, showing that bacteria and insects had evolved in lockstep (PLoS Biology, DOI: 10.1371/journal.pbio.0040337). This was completely unexpected for bacteria living free in an insect’s gut. Moreover, the bacteria have the same shrunken genomes and other changes seen in disease bacteria such as chlamydia. The team thinks these changes reflect the way bacteria adapt to a host, whether as helpers or as parasites. “This is likely to provide insights into the evolution of bacterial pathogens,” Fukatsu says. The way the plataspids deliver capsules of bacteria to their eggs will allow researchers to investigate this further by manipulating the host and bacteria separately.
Wobble killed off mammal species MAMMALIAN species are known to last an average of 2.5 million years before being snuffed out, but nobody had been able to figure out why. The reason, it turns out, may be linked to regular wobbles in Earth’s orbit. Jan van Dam from Utrecht University in the Netherlands and colleagues reached this conclusion after studying the fossil record of rodents from central Spain over a 22-millionyear span. This showed a link between rodent extinction events and the climate record. Changes in the Earth’s tilt and the shape of its orbit lead to climate cycles of around 1.2 and 2.4 million years. At their extremes both these cycles cause global cooling, expansion of polar ice sheets and changes in rainfall patterns. The extinction peaks coincided with global cooling maxima, while new appearance peaks coincided with periods of stable climate (Nature, DOI: 10.1038/nature05163). “Changes in seasonality associated with the astronomical variations – harsh winters, dry summers – are really a matter of life and death to mammals,” van Dam points out.
IT’S not a treatment for the fainthearted. Now it seems that not only do maggots eat away the dead tissue from wounds and allow healing to begin, they also secrete a fluid containing enzymes to speed up the healing process. Stephen Britland at the University of Bradford, UK, and his colleagues applied extracts of maggot juice to layers of cells that mimic skin. When circular “wounds” were created in the cell layers, those exposed to the maggot extracts healed fastest (Biotechnology Progress, DOI: 10.1021/ bp0601600).
www.newscientist.com