The oldest evidence of
photosynthetic structures
reported to date has been
identified inside a collection of 1.75billionyearold
microfossils, a paper published in the journal Nature reveals. The discovery
helps to shed light on the
evolution of oxygenic
photosynthesis.
Oxygenic photosynthesis, in which sunlight catalyses the conversion of water and carbon dioxide into
glucose and oxygen, is unique to cyanobacteria and
related organelles within
eukaryotes. Cyanobacteria
had an important role in
the evolution of early life
and were active during the
Great Oxidation Event
around 2.4 billion years
ago, but the timings of the
origins of oxygenic photosynthesis are debated owing to limited evidence.
Catherine Demoulin
from the University of
Liège, Liège, Belgium and
others present direct evidence of fossilised photosynthetic structures from
Navifusa majensis. The microstructures are thylakoids; membrane bound
structures found inside the
chloroplasts of plants and
some modern cyanobacteria.
Catherine Demoulin
from the University of
Liège, Liège, Belgium and
others present direct evidence of fossilised photosynthetic structures from
Navifusa majensis. The microstructures are thylakoids; membrane bound
structures found inside the
chloroplasts of plants and
some modern cyanobacteria.
The authors identified
The authors identified
them in fossils from two
different locations, but the
oldest, which come from
the McDermott Formation
in Australia, are 1.75 billion
years old.
N. majensis is presumed
to be a cyanobacterium.
The discovery of thylakoids in a specimen of this
age suggests that photosynthesis may have
evolved at some point before 1.75 billion years ago.
It does not, however, solve
the mystery of whether
photosynthesis evolved before or after the Great Oxidation Event. Similar ultrastructural analyses of
older microfossils could
help to answer this question, the authors say, and
help to determine whether
the evolution of thylakoids
contributed to the rise in
oxygen levels at the time of
the Great Oxidation Event.
Thylakoids represent direct ultrastructural evidence for oxygenic photosynthesis metabolism.
Thylakoid membranes are
dense, mostly galactolipid,
protein containing bilayers
in which photosynthesis
occurs in photosynthetic
organisms. “The discovery
of preserved thylakoids in
N. majensis from both the
Shaler Supergroup and Tawallah Group provides di
rect evidence for oxygenic
photosynthesis, for a cyanobacterial affinity and for
metabolically active vegetative cell rather than a cyst
(akinete) stage for these
specimens,” they note.
“We predict that similar
ultrastructural analyses of
well preserved microfossils might expand the geological record of oxygenic
photosynthesisers, and of
early, weakly oxygenated
ecosystems in which complex cells developed,” they
write.
The oldest evidence of
photosynthetic structures
reported to date has been
identified inside a collection of 1.75billionyearold
microfossils, a paper published in the journal Nature reveals. The discovery
helps to shed light on the
evolution of oxygenic
photosynthesis.
Oxygenic photosynthesis, in which sunlight catalyses the conversion of water and carbon dioxide into
glucose and oxygen, is unique to cyanobacteria and
related organelles within
eukaryotes. Cyanobacteria
had an important role in
the evolution of early life
and were active during the
Great Oxidation Event
around 2.4 billion years
ago, but the timings of the
origins of oxygenic photosynthesis are debated owing to limited evidence.
Catherine Demoulin
from the University of
Liège, Liège, Belgium and
others present direct evidence of fossilised photosynthetic structures from
Navifusa majensis. The microstructures are thylakoids; membrane bound
structures found inside the
chloroplasts of plants and
some modern cyanobacteria.
The authors identified
them in fossils from two
different locations, but the
oldest, which come from
the McDermott Formation
in Australia, are 1.75 billion
years old.
N. majensis is presumed
to be a cyanobacterium.
The discovery of thylakoids in a specimen of this
age suggests that photosynthesis may have
evolved at some point before 1.75 billion years ago.
It does not, however, solve
the mystery of whether
photosynthesis evolved before or after the Great Oxidation Event. Similar ultrastructural analyses of
older microfossils could
help to answer this question, the authors say, and
help to determine whether
the evolution of thylakoids
contributed to the rise in
oxygen levels at the time of
the Great Oxidation Event.
Thylakoids represent direct ultrastructural evidence for oxygenic photosynthesis metabolism.
Thylakoid membranes are
dense, mostly galactolipid,
protein containing bilayers
in which photosynthesis
occurs in photosynthetic
organisms. “The discovery
of preserved thylakoids in
N. majensis from both the
Shaler Supergroup and Tawallah Group provides di
rect evidence for oxygenic
photosynthesis, for a cyanobacterial affinity and for
metabolically active vegetative cell rather than a cyst
(akinete) stage for these
specimens,” they note.
“We predict that similar
ultrastructural analyses of
well preserved microfossils might expand the geological record of oxygenic
photosynthesisers, and of
early, weakly oxygenated
ecosystems in which complex cells developed,” they
write.