Details of Award
NERC Reference : NE/C510975/1
Biodiversity, ecology and population structure of cercozoan Protozoa.
Grant Award
- Principal Investigator:
- Professor T Cavalier-Smith, University of Oxford, Zoology
- Grant held at:
- University of Oxford, Zoology
- Science Area:
- Terrestrial
- Marine
- Freshwater
- Overall Classification:
- Terrestrial
- ENRIs:
- Biodiversity
- Science Topics:
- Environmental Microbiology
- Population Genetics/Evolution
- Systematics & Taxonomy
- Community Ecology
- Abstract:
- In all environments carbon and nutrients are recycled by organisms that decompose dead plants (or plant parts like fallen leaves) and animals. Microorganisms are much more important than animals in these decomposer pathways. The first step is digestion of dead material by bacteria and microscopic fungi which digest it externally by secreting digestive enzymes into their environment. Bacteria and fungi are in turn eaten by predatory single-celled organisms. the Protozoa, which also prey on single-celled algae in the soil and natural waters. Protozoa, which also prey on each other, are now divided into 13 major groups (phyla), each with distinctive body plans (just as animals are divided into phyla such as arthropods and molluscs). In soil the most important protozoan phylum for natural chemical recycling is the Cercozoa. Although I established this new phylum only in 1998, we have shown by culturing cells and by sequencing their genes and also others obtained directly from DNA extracted from environmental samples that Cercozoa has thousands of species, 10 classes and 8 mystery groups known only from environmental DNA sequencing. The biodiversity of Cercozoa is therefore immense - perhaps as great as that of any other protozoan phylum, but has been largely unstudied. We shall use culturing of cells, group-specific amplification of a gene for ribosomal RNA (a key part of the cellular machinery for making proteins) and microscopy to show what sorts of organisms each mystery group contains. We shall also use the same methods to characterize in more detail the biodiversity of two of the most important classes of Cercozoa in soil and study their ecology: Proteomyxidea (amoebae with very thin projecting strands of protoplasm that are often net-like and extend among soil particles to help them catch prey) and Sarcomonadea (flagellates that can swim but mainly use their posterior cilium to glide on surfaces of soil particles - like skiing; some of them can also form protoplasmic threads or fuse together into larger masses of protoplasm). We shall sequence genes for a large protein called heat shock protein 90 from three different genera of sarcomonads (Cercomonas, Heteromita - the commonest flagellates in soil - and Bodomorpha) to see whether mutations in this gene are being recombined by sexual reproduction as in higher organisms or whether instead these Cercozoa are non-sexual like bacteria. We shall use these protein sequences also to decide whether each cell has one copy only of the genome or two (like animals) and to work out a better evolutionary family tree independent of that from ribosomal RNA to show better how the major groups of Cercozoa are related to each other. We shall sequence cercozoan robosomal RNA genes in DNA extracted from numerous samples from different habitats to see whether different genetic types are adapted to specific environments. Cercozoa live in the open sea and on the sea floor as well as in soil. Although they are virtually everywhere, this will be the first time that the abundance of specific genetic types has been measured quantitatively. We hypothesize that each kind will turn out to have a specific habitat. Because many of them look so similar under the microscope numerous 'species' have been artificially lumped together and confused with each other. Therefore detailed study of their roles in natural and man-modified environments was not previously possible till we developed discriminating molecular tools to study the genes of each individual type directly. Until we know whether or not they are sexual we shall not even know if they have real species (interbreeding units) like most animals and plants. Our research should also tell us whether some of them are more important quantitatively than others in soil biology, which may be important for understanding the long-term health of the soil under modern methods of farming and forestry.
- NERC Reference:
- NE/C510975/1
- Grant Stage:
- Completed
- Scheme:
- Standard Grants Pre FEC
- Grant Status:
- Closed
- Programme:
- Standard Grant
This grant award has a total value of £239,292
FDAB - Financial Details (Award breakdown by headings)
| Total - T&S | Total - Staff | Total - Other Costs | Total - Indirect Costs |
|---|---|---|---|
| £3,748 | £111,892 | £55,620 | £68,030 |
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