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  • Phylogenetic relationships within the moss family Bryaceae based on chloroplast DNA evidence
    Publication . Cox, C. J.; Hedderson, T. A. J.
    The Bryaceae are a large cosmopolitan family of mosses containing genera of considerable taxonomic difficulty. Phylogenetic relationships within the family were inferred using data from chloroplast DNA sequences (rps4 and trnL-trnF region). Parsimony and maximum likelihood optimality criteria, and Bayesian phylogenetic inference procedures were employed to reconstruct relationships. The genera Bryum and Brachymenium are not monophyletic groups. A clade comprising Plagiobryum, Acidodontium, Mielichhoferia macrocarpa, Bryum sects. Bryum, Apalodictyon, Limbata, Leucodontium, Caespiticia, Capillaria (in part: sect. Capillaria), and Brachymenium sect. Dicranobryum, is well supported in all analyses and represents a major lineage within the family. Section Dicranobryum of Brachymenium is more closely related to section Bryum than to the other sections of Brachymenium, as are Mielichhoferia macrocarpa and M. himalayana. Species of Acidodontium form a clade with Anomobryum julaceum. The grouping of species with a rosulate gametophytic growth form suggests the presence of a 'rosulate' clade similar in circumscription to the genus Rosulabryum. Mielichhoferia macrocarpa and M. himalayana are transferred to Bryum as B. porsildii and B. caucasicum, respectively.
    2003-03Journal article Restricted access Show more
  • Does the interrenal influence sex differentiation in sea bass, Dicentrarchus labrax?
    Publication . Martins, Rute Sofia Tavares; Canário, Adelino
    Sea bass Dicentrarchus labrax is one of the most important cultured species in Mediterranean aquaculture. This species remains sexually immature most of the first year of life, and at the time of marketing (2 years old), females are 18-40% heavier than males. However, in cultured populations, it is frequently reported skewed sex ratios in favour of males (reaching 70-99%), and thus, the acquisition of all-female stocks is an attractive option for sea bass aquaculture. The underlying hypothesis of this work is that in intensive culture, the sea bass interrenal tissue produces corticosteroids in response to stress, and together with them an excess of adrenal androgens shifting the normal androgen/ estrogen ratio and thus leading to gonadal masculinization. Thus, blocking cortisol production with an antagonist (Dexamethasone) during the androgen sensitive period would most likely decrease the androgen levels and thereby the sex ratios would be altered.
    2003-03Master thesis Open access Show more