In Silico and Biochemical Analysis of Physcomitrella patens Photosynthetic Antenna: Identification of Subunits which Evolved upon Land Adaptation

Background. In eukaryotes the photosynthetic antenna system is composed of subunits encoded by the light harvesting complex (Lhc) multigene family. These proteins play a key role in photosynthesis and are involved in both light harvesting and photoprotection. The moss Physcomitrella patens is a member of a lineage that diverged from seed plants early after land colonization and therefore by studying this organism, we may gain insight into adaptations to the aerial environment. Principal Findings. In this study, we characterized the antenna protein multigene family in Physcomitrella patens, by sequence analysis as well as biochemical and functional investigations. Sequence identification and analysis showed that some antenna polypeptides, such as Lhcb3 and Lhcb6, are present only in land organisms, suggesting they play a role in adaptation to the sub-aerial environment. Our functional analysis which showed that photo-protective mechanisms in Physcomitrella patens are very similar to those in seed plants fits with this hypothesis. In particular, Physcomitrella patens also activates Non Photochemical Quenching upon illumination, consistent with the detection of an ortholog of the PsbS protein. As a further adaptation to terrestrial conditions, the content of Photosystem I low energy absorbing chlorophylls also increased, as demonstrated by differences in Lhca3 and Lhca4 polypeptide sequences, in vitro reconstitution experiments and low temperature fluorescence spectra. Conclusions. This study highlights the role of Lhc family members in environmental adaptation and allowed proteins associated with mechanisms of stress resistance to be identified within this large family

Analysis of LhcSR3, a Protein Essential for Feedback De-Excitation in the Green Alga Chlamydomonas reinhardtii

To prevent photodamage by excess light, plants use different proteins to sense pH changes and to dissipate excited energy states. In green microalgae, however, the LhcSR3 gene product is able to perform both pH sensing and energy quenching functions

Platform-Independent Modelling in MDA: Supporting Abstract Platforms

An MDA-based design approach should be able to accommodate designs at different levels of platform-independence. We have previously proposed a design approach, which allows these levels to be identified. An important feature of this approach is the notion of abstract platform. An abstract platform is determined by considering the platform characteristics that are relevant for applications at a certain level of platform-independence as well as the various design goals. In this paper, we discuss how our design approach can be supported using the MDA standards UML 2.0 and MOF 2.0. Since our methodological framework is based on the notion of abstract platform, we pay particular attention to the representation of abstract platforms and the language requirements to specify abstract platforms

9th International Workshop on Aspect-Oriented Modeling (Report)

This report summarizes the outcomes of the 9th Workshop on Aspect-Oriented Modeling (AOM) held in conjunction with the 9th International Conference on Model Driven Engineering Languages and Systems \u2013 MoDELS 2006 \u2013 in Genoa, Italy, on the 1st of October 2006. The workshop brought together approximately 25 researchers and practitioners from two communities: aspect-oriented software development and software model engineering. It provided a forum for discussing the state of the art in modeling crosscutting concerns at different stages of the software development process: requirements elicitation and analysis, software architecture, detailed design, and mapping to aspect-oriented programming constructs. This paper gives an overview of the accepted submissions and summarizes the results of the different discussion groups. Papers and presentation slides of the workshop are available at http://www.aspect-modeling.org/