1. Iron-sulphur cluster assembly and bio-hydrogen production in algae
Project Supervisor: Dr Janneke Balk
The "iron-only" hydrogenases are enzymes that use exclusively iron and sulphide to catalyse the production of hydrogen. As such, they provide a cheap alternative to platinum electrodes currently used for the industrial production of hydrogen gas. Our laboratory is studying the assembly of these natural catalysts, or Fe-S cofactors, in the green alga Chlamydomonas reinhardti, a model organism for the production of bio-hydrogen. This project will focus on the role of alga-specific assembly factors that we have recently identified (Godman & Balk, Genetics 2008). Using a reverse genetics approach based on RNAi silencing (in collaboration with David Baulcombe's group) the importance of the candidate genes for hydrogen production will be assessed. In addition, the regulation of Fe-S cluster assembly during hydrogenase-inducing conditions (high light / low oxygen / low sulphur) will be investigated.
2. Ca2+-dependent signalling networks in Chlamydomonas
Project Supervisors: Drs Julia Davies and Alex Webb
Changes in cytosolic free Ca2+ ([Ca2+]cyt) play diverse signalling roles in eukaryote cells, from regulation of the cell cycle, the response to stress and in the maintenance of circadian rhythms. Ca2+-dependent signalling networks must therefore display specificity to coordinate these different cellular functions. Genome sequencing of the unicellular alga Chlamydomonas has indicated a surprising mix of plant- and animal-like Ca2+ transporters and receptors required for determining specificity in these Ca2+ signalling networks . This alga therefore occupies an intriguing evolutionary position to inform us on the development of fundamental signalling processes in eukaryotes. The project will combine high resolution imaging of cytosolic Ca2+ in Chlamydomonas with a range of biochemical and molecular techniques. Candidate components of [Ca2+]cyt-dependent stress signalling pathways and the circadian clock  will be knocked down using RNAi to deduce their role. The project is a collaboration between the Cambridge Transport and Signalling Groups (Drs. Julia Davies and Alex Webb), Prof. Colin Brownlee (Marine Biological Association) and Dr. Glen Wheeler (Plymouth Marine Laboratory).
 TiPS 13: 506.  Science 318: 1789.
3. Iridescence In Algae: How & Why?
Supervisor: Dr Beverley Glover
Iridescence is the property of appearing different colours when viewed from different angles. It occurs when different wavelengths of light are reflected from a surface at different angles, and gives the vivid rainbow appearance to the feathers of peacocks and the wings of many butterflies and beetles. Iridescence in animals has been extensively investigated, and has a range of roles in intraspecific signalling. Iridescence is not isolated to the animal kingdom, but much less is known about it in photosynthetic organisms. Green and brown algae have been recorded as iridescent, but the phenomenon is most commonly found in red algae, where blue and green colours appear on the surface at certain stages of the lifecycle. The structural basis for this is unknown, and will be studied using a combination of microscopical and modelling approaches in the British species Chondria coerulescens and Drachiella spectabilis.
The function of algal iridescence is also unclear. Suggestions include a role in camouflage or a role in optimising photosynthesis by enhancing the absorption of useful wavelengths of light at the expense of increased reflection of other wavelengths. Optical analysis of the algae will be complemented by analysis of their photosynthetic capacity under different light regimes, to distinguish between these hypotheses.
4. Transcript analysis of the Coleochaete orbicularis algal genome.
Project Supervisor: Dr Jim Haseloff
Members of the genus Coleochaete are multicellular green algae, and exhibit some of the earliest and simplest features of multicellular plant growth. Haploid zoospores initiate the growth of discoid multicellular colonies. The colonies adhere to the substrate and grow as a cell monolayer. The circular morphology of the colonies is maintained by precisely coordinated sequences of anticlinal and periclinal divisions. Cultures are easy to maintain on agar plates and are ideal for microscopy. Coleochaete has been little studied as a developmental system, but shows unique promise for genetic studies. (i) High throughput sequencing approaches will be used to generate the first comprehensive description of expressed sequences in Coleochaete. (ii) A catalogue of predicted protein sequences will be generated and compared to that of higher plants and other algae. (iii) Predicted promoters will be isolated and used for gene expression studies.
Coordination of plant cell division and expansion in a simple morphogenetic system. Dupuy, L., Mackenzie, J. and Haseloff, J., Proc. Natl. Acad. Sci. (USA) 107:2711-6, 2010.
5. RNA Silencing in Chlamydomonas
Supervisor: Prof Sir David Baulcombe
RNA silencing is a recently discovered genetic and epigenetic mechanism in growth, development, responses to environmental stimuli and in resistance against viruses. Recently, through work with higher plants, the small RNA species associated with RNA silencing have also been implicated in genome interactions associated with hybrid incompatibility, hybrid vigour and with transgressive segregation in which offspring exhibit phenotypes that are outside the range of the parents.
The proposed project is to investigate these effects in hybrids of North American and Japanese isolates of Chlamydomonas. The patterns of gene expression will be assessed in zygotes and derivative hybrid lines in order to identify molecular phenotypes that deviate from the mid parental value. Genetic and molecular analysis will be carried out in order to characterise the underlying mechanisms.
The mysterious phenotypes of hybrids are one of the big mysteries of modern biology. The project will help solve this mystery by taking advantage of the short time scale of hybridisation in a unicellular alga as compared to multicellular organisms. It will generate information that is relevant to the understanding of various aspects of evolution including mechanisms associated with speciation. There could also be an applied aspect of the project as the information could be used in the development of improved strains for production of biofuels and other chemicals. The project will introduce techniques in molecular biology and there will be a substantial bioinformatic component associated with the analysis of expression profiling data.
The Lewin-Fritsch Studentship supports a research studentship in phycology (algal biology). All College and University Fees will be paid on behalf of the student, who will receive, in addition, a living allowance and a contribution towards to the cost of his or her research. The value of the allowance and research contribution is determined annually by the Electors by reference to other similar studentships, notably the Wellcome Studentships and the Gatsby Awards, The Studentship is linked to Downing College, where the student will become a Graduate Member. Only specific projects (those listed above) are eligible for consideration.
Full funding is available for UK residents and EU citizens who have been resident in the UK for at least 3 years.
The minimum qualification for Ph.D. studies is a Class 2.1 Honours Bachelors Degree, or a Masters degree (or equivalent).
You must complete an online ‘Graduate Admission and Scholarship Application Form’ (GRADSAF). In addition to this you must send your supporting documentation: Two academic references, CV, Full Academic Transcript & Research Proposal to the:
Graduate Student Administrator
Department of Plant Sciences
by the closing date, which is 30th April 2010
Informal enquiries can be directed to firstname.lastname@example.org.