such as "Introduction", "Conclusion"..etc
December 2008 -- A Swedish research group has discovered a new mechanism for cell
division in a microorganism found in extremely hot and acidic
conditions. The results of the research offer insights into evolution,
but also into the functioning of the human body.
The new mechanism for cell division was discovered in Sulfolobus
acidocaldarius, a microorganism found in hot springs in Yellowstone
National Park. The organism is a member of the third main group of life
on earth, the Archaea. Archaea, like bacteria, are unicellular
organisms but in terms of evolution they are more closely related to
another main group of living things, the eukaryotes (humans, animals,
plants, fungi, etc).
Until now little was known about the proteins that control cell
division in the Archaea. With the use of immunofluorescence the
researchers determined the location of these proteins in the cell and
in doing so discovered that three proteins play a crucial role in the
cell division of Sulfolobus acidocaldarius. Once the whole chromosome
has been replicated, these three proteins form a band-like structure
over the cell equator. One chromosome is then found on each side of
this band. The band then squeezes the cell into two so that two new
daughter cells are formed. At first it looks like mitosis, as discussed
in many a biology lesson. However, mitosis is the process whereby the
chromosomes are distributed between the two daughter cells. Cell
division is the process whereby the two daughter cells are separated.
It is striking that these cell division proteins are not related to
other proteins known to be involved in cell division. Some of the
proteins in the new type of cell division are similar to proteins in
other eukaryotes that have a completely different function. The study
shows that the proteins involved in cell division in Sulfolobus
acidocaldarius are related to the so-called ESCRT proteins. In
eukaryotes, and therefore also in humans, these proteins are involved
in protein transport within the cell. It has recently been shown that
the HIV virus makes use of the ESCRT transport system to escape from
the host cell. Studying the process of cell division in Sulfolobus
acidocaldarius could therefore lead to new insights into the processes
involving ESCRT proteins, such as HIV particle release.
Some theories suggest that in evolutionary terms the Archaea are the
predecessors of eukaryotes. This is confirmed by the fact that genes
involved in cell division in Sulfolobus acidocaldarius are related to
eukaryotic genes. In one way or another, these organisms are related to
us humans. The study shows that this resemblance is possibly somewhat
closer than at first thought.
Among other things, microbiologist Thijs Ettema has taken a closer
look at the resemblance between the cell division proteins and the
This research was partly financed by the Netherlands Organization
for Scientific Research. Thijs Ettema, member of the research group,
received a Rubicon grant from NWO in 2006 to gain experience abroad.
Full text : Lindas et al. A unique cell division machinery in the Archaea. Proceedings of the National Academy of Sciences, November 5, 2008; DOI: 10.1073/pnas.0809467105
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