Bug vs bug
Cyanobacteria are among the first microorganisms to have inhabited the Earth. Throughout the last few billion years, they have played a major role in shaping the Earth as the planet we live in, and they continue to play a significant role in our everyday lives.
Cyanobacteria are often referred to as blue-green algae but have no direct relation to higher algae. They are one of the oldest organisms on Earth with fossil records dating back 3.5 billion years. Cyanobacteria are responsible for the Earth’s transition from a carbon dioxide-rich atmosphere to the present relatively oxygen-rich atmosphere as a consequence of oxygenic photosynthesis. Throughout their long evolutionary history, cyanobacteria have diversified into a variety of species with various morphologies and niche habitats. Cyanobacteria inhabit a diverse range of terrestrial and aquatic habitats, ranging from deserts to freshwater and marine systems across a range of eutrophic and oligotrophic conditions. They can also be found in extreme environments, such as Antarctic dry valleys, Arctic and thermophilic lakes, as well as in unlikely habitats for phototrophs, such as in the subsurface of calcareous rocks and lava caves.
Cyanophages are viruses that infect cyanobacteria. Like their hosts, they are extremely abundant and widely distributed in the world’s oceans, where they play important roles in regulating the metabolic activity, evolution, and community structures of cyanobacteria. The infection of cyanobacteria by cyanophages significantly influences global biogeochemical cycles. Cyanophages can modify cyanobacteria photosynthesis by inhibiting CO₂ fixation to maximise energy for phage propagation, leading to an estimated loss of billions of metric tonnes of fixed carbon per year.
A team of researchers at the Hong Kong University of Science and Technology led by Dr Dang Shangyu and Dr Zeng Qinglu of the Division of Life Sciences used single-particle cryo-electron microscopy to examine the cyanophage P-SCSP1u at near-atomic resolution including a part of the virus called the portal-tail complex.
“We believe this high-resolution native structure of cyanophage is an important and timely contribution to the field of bacteriophages for the understanding of viral infection,” said Dang.
The findings were published in the journal Nature Communications.