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Biomedical subjects

Christophe Godin

Publications and source records attributed to Christophe Godin.

5 recordsLinked to original sources
PubMed2006

Computer simulations reveal properties of the cell-cell signaling network at the shoot apex in Arabidopsis.

The active transport of the plant hormone auxin plays a major role in the initiation of organs at the shoot apex. Polar localized membrane proteins of the PIN1 family facilitate this transport, and recent observations suggest that auxin maxima created by these proteins are at the basis of organ initiation. This hypothesis is based on the visual, qualitative characterization of the complex distribution patterns of the PIN1 protein in Arabidopsis. To take these analyses further, we investigated the properties of the patterns using computational modeling. The simulations reveal previously undescribed properties of PIN1 distribution. In particular, they suggest an important role for the meristem summit in the distribution of auxin. We confirm these predictions by further experimentation and propose a detailed model for the dynamics of auxin fluxes at the shoot apex.

Arabidopsis↗
PubMed2006

Definition of architectural ideotypes for good yield capacity in Coffea canephora.

BACKGROUND: Yield capacity is a target trait for selection of agronomically desirable lines; it is preferred to simple yields recorded over different harvests. Yield capacity is derived using certain architectural parameters used to measure the components of yield capacity. METHODS: Observation protocols for describing architecture and yield capacity were applied to six clones of coffee trees (Coffea canephora) in a comparative trial. The observations were used to establish architectural databases, which were explored using AMAPmod, a software dedicated to the analyses of plant architecture data. The traits extracted from the database were used to identify architectural parameters for predicting the yield of the plant material studied. CONCLUSIONS: Architectural traits are highly heritable and some display strong genetic correlations with cumulated yield. In particular, the proportion of fruiting nodes at plagiotropic level 15 counting from the top of the tree proved to be a good predictor of yield over two fruiting cycles.

Agriculture↗
PubMed2005

A protocol to analyse cellular dynamics during plant development.

In vivo microscopy generates images that contain complex information on the dynamic behaviour of three-dimensional (3D) objects. As a result, adapted mathematical and computational tools are required to help in their interpretation. Ideally, a complete software chain to study the dynamics of a complex 3D object should include: (i) the acquisition, (ii) the preprocessing and (iii) segmentation of the images, followed by (iv) a reconstruction in time and space and (v) the final quantitative analysis. Here, we have developed such a protocol to study cell dynamics at the shoot apical meristem in Arabidopsis. The protocol uses serial optical sections made with the confocal microscope. It includes specially designed algorithms to automate the identification of cell lineage and to analyse the quantitative behaviour of the meristem surface.

Anatomy, Cross-Sectional↗
PubMed2002

Hyperstructures, genome analysis and I-cells.

New concepts may prove necessary to profit from the avalanche of sequence data on the genome, transcriptome, proteome and interactome and to relate this information to cell physiology. Here, we focus on the concept of large activity-based structures, or hyperstructures, in which a variety of types of molecules are brought together to perform a function. We review the evidence for the existence of hyperstructures responsible for the initiation of DNA replication, the sequestration of newly replicated origins of replication, cell division and for metabolism. The processes responsible for hyperstructure formation include changes in enzyme affinities due to metabolite-induction, lipid-protein affinities, elevated local concentrations of proteins and their binding sites on DNA and RNA, and transertion. Experimental techniques exist that can be used to study hyperstructures and we review some of the ones less familiar to biologists. Finally, we speculate on how a variety of in silico approaches involving cellular automata and multi-agent systems could be combined to develop new concepts in the form of an Integrated cell (I-cell) which would undergo selection for growth and survival in a world of artificial microbiology.

Algorithms↗