Vincent Demoulin

Phylogenomic Evidence for Separate Acquisition of Plastids in Cryptophytes, Haptophytes, and Stramenopiles

According to the chromalveolate hypothesis (Cavalier-Smith T. 1999. Principles of protein and lipid targeting in secondary symbiogenesis: euglenoid, dinoflagellate, and sporozoan plastid origins and the eukaryote family tree. J Eukaryot Microbiol 46:347-366), the four eukaryotic groups with chlorophyll c-containing plastids originate from a single photosynthetic ancestor, which acquired its plastids by secondary endosymbiosis with a red alga. So far, molecular phylogenies have failed to either support or disprove this view. Here, we devise a phylogenomic falsification of the chromalveolate hypothesis that estimates signal strength across the three genomic compartments: If the four chlorophyll c-containing lineages indeed derive from a single photosynthetic ancestor, then similar amounts of plastid, mitochondrial, and nuclear sequences should allow to recover their monophyly. Our results refute this prediction, with statistical support levels too different to be explained by evolutionary rate variation, phylogenetic artifacts, or endosymbiotic gene transfer. Therefore, we reject the chromalveolate hypothesis as falsified in favor of more complex evolutionary scenarios involving multiple higher order eukaryote-eukaryote endosymbioses.

A Comparative Inventory of Metal Transporters in the Green Alga Chlamydomonas reinhardtii and the Red Alga Cyanidioschizon merolae

As in all organisms, metal cations are crucial for nutrition in plants. Several metals, such as copper, iron, zinc, and manganese, act as important cofactors for many enzymes and are essential for both mitochondrial and chloroplast functions. However, when supplied in excess, these essential cations

History and clinical features of atypical myopathy in horses in Belgium (2000-2005)

BACKGROUNDnThe emergent nature of atypical myopathy or atypical myoglobinuria (AM) necessitates precise description of its clinical and epidemiologic features.nnnPURPOSEnTo define key features of AM to help practitioners recognize the disease and to advise owners to take preventive measures.nnnANIMALSnBelgian cases of AM confirmed by histology (CC horses; n = 57) from autumn 2000 to spring 2005 were included in the study. Co-grazing horses (Co-G horses; n = 77) that remained free of any abnormal clinical signs constituted a control group.nnnMETHODSnHistory, environmental characteristics, clinical signs, and laboratory results associated with AM were determined by a retrospective case series study.nnnRESULTSnYoung horses in poor or normal body condition were found to be at risk for AM. Pastures were characterized by poor natural drainage and vegetation of low nutritional value. Features of AM were seasonal occurrence, apparent link with weather conditions (ie, lack of solar radiation with no heavy frost and an excess of precipitation or relative humidity), sudden onset of clinical signs, and rapid death. Evaluation of serum creatine kinase activity indicated severe muscle destruction in CC horses and subclinical disease in a few Co-G horses.nnnCONCLUSIONSnThe association of AM with specific environmental conditions and individual animals suggests that young horses should not be pastured on bare premises subject to humidity when the weather has been very wet and cold for several days. Management of AM outbreaks should include control of Co-G horses who are apparently healthy.

Anthesis effects on Posidonia oceanica (L.) Delile phenology in the Bay of Calvi (Corsica, Mediterranean Sea)

In Posidonia oceanica (L.) Delile, anthesis induces a decrease in the number of juvenile leaves resulting in a significant reduction in the number of leaves on the flowering shoots. All the leaves of the flowering shoots are narrower than the leaves of nonflowering shoots. A modification of the leaf growth also appears in flowering shoots: the oldest leaves are longer and the leaves induced during or after anthesis are shorter. At 10 m depth, in the Bay of Calvi, anthesis lasts roughly 3 months and the flowering is induced 7 months before anthesis.

The sad story of Agaricus rhacodes/rachodes: Why would an orthographical error with limited current use become accepted through conservation?

The spelling rachodes used by Vittadini in 1833 for a new species of Agaricus has often been considered a correct- able orthographical error for rhacodes. Use of the original spelling has however been occasional and was recently promoted by Vellinga and coworkers. The arguments used to support this practice, especially developed by Vellinga and Pennycook, when proposing conservation of rachodes in 2010 are refuted. It is shown that it is philologically illogical to assume an adjective rachodes could have been created, while the existing rhacodes was obviously meant. The use of the two spellings presented by Vellinga and Pennycook is shown to be incomplete. The conclusion is that rachodes should be corrected under Art. 60.1 to rhacodes, the spelling used for every other organism with that epithet, and that this correction is far more universal, including outside Europe, than the usage claimed for justifying a conservation of rachodes. The expenditure of energy caused by the Vellinga and Pennycook proposal shows that new ways to handle orthography of scientific names should be explored.