The action of excessive,inorganic silicon (Si) on the mineral metabolism of calcium (Ca) and magnesium (Mg)

The influence of silicon treatment on the levels of calcium and magnesium in blood serum and tissues was studied in rats. The concentrations of both elements were estimated in samples of sera and tissues of rats receiving per os a soluble, inorganic silicon compound—sodium metasilicate nonahydrate (Na₂SiO₃·9H₂O (REACHIM, USSR)), dissolved in the animals' drinking water. A decrease of magnesium concentration in serum was observed with accompanying elevation of registered calcemia. Moreover, a reduction of tissue calcium levels was found with a simultaneous increase of magnesium tissue pool. The results provide evidence for silicon involvement in mineral metabolism. It could result in a modification of pathological processes concerning bone tissue.     

Morphological assessment of the Octopus vulgaris species complex evaluated in light of molecular‐based phylogenetic inferences

Cryptic species are common in the ocean, particularly among marine invertebrates such as octopuses. Delineating cryptic species is particularly problematic in octopus taxonomy where the plasticity recorded among taxonomic characters often results in low resolution at the species level. This study investigated the morphological relationships among seven phylogenetic clades (identified using cytochrome c oxidase subunit I) of the broadly distributed Octopus vulgaris species complex and close relatives. Morphological analyses in this study were successful in delimiting O. sinensis, Brazilian O. vulgaris and O. vulgaris sensu stricto, which was congruent with the molecular findings of this study. Analyses based on male morphology were successful in distinguishing 14 of 15 total pairwise comparisons and proved to be a more reliable indicator of species‐level relationships in comparison with female morphology. The majority of characters with the greatest discriminatory power were male sexual traits. Significant morphological differences were also recorded among sampling localities of conspecifics, with phenotype showing correlation with local environmental data. The findings of this study support the hypothesis that multiple O. vulgaris‐like species are currently being incorrectly treated under a single species name, O. vulgaris. Octopuses being exported globally under the name O. vulgaris are of extremely high fisheries market value and profile. Our findings have potentially significant implications for the naming and conservation of commercially harvested members of this species complex throughout their ranges.     

Regeneration of a Gentiana pneumonanthe population in an oligotrophic wet meadow

Abstract. The aim of this study was to evaluate the critical phases of the life cycle of Gentiana pneumonanthe, the marsh gentian, a threatened species of the Bohemian flora. The effect of various conditions on germination and seedling establishment and the possible effect of competition on the performance of the species were tested. Seeds were sown in plots which were subjected to four treatments in a randomized complete blocks experiment: unmanaged meadow, mown meadow, burned meadow, and meadow with cut sod. The significantly highest recruitment was found in plots with cut sod, the lowest in the unmanaged control plots. Seedling survival also differed among the treatments. In the following year surviving individuals were only found in plots with cut sod. The influence of neighbouring vegetation on target gentian individuals was evaluated by removing the surrounding vegetation and comparing the performance of these individuals with controls. The initial height of each individual was measured and used as a covariable. No significant effect of neighbouring vegetation on performance was detected. Thus, the establishment phase appears to be critical for population persistence and is also more influenced by the management regime than other stages of the life cycle.     

Four kilograms of information: ramdom thoughts on Histocompatibility Testing 1987

B. Dupont (ed.): Immunobiology of HLA, Vol. I, Histocompatibility Testing 1987; Vol. II, Immunogenetics and Histocompatibility, Springer, New York, 1989.     

Green land: Multiple perspectives on green algal evolution and the earliest land plants

Green plants, broadly defined as green algae and the land plants (together, Viridiplantae), constitute the primary eukaryotic lineage that successfully colonized Earth's emergent landscape. Members of various clades of green plants have independently made the transition from fully aquatic to subaerial habitats many times throughout Earth's history. The transition, from unicells or simple filaments to complex multicellular plant bodies with functionally differentiated tissues and organs, was accompanied by innovations built upon a genetic and phenotypic toolkit that have served aquatic green phototrophs successfully for at least a billion years. These innovations opened an enormous array of new, drier places to live on the planet and resulted in a huge diversity of land plants that have dominated terrestrial ecosystems over the past 500 million years. This review examines the greening of the land from several perspectives, from paleontology to phylogenomics, to water stress responses and the genetic toolkit shared by green algae and plants, to the genomic evolution of the sporophyte generation. We summarize advances on disparate fronts in elucidating this important event in the evolution of the biosphere and the lacunae in our understanding of it. We present the process not as a step-by-step advancement from primitive green cells to an inevitable success of embryophytes, but rather as a process of adaptations and exaptations that allowed multiple clades of green plants, with various combinations of morphological and physiological terrestrialized traits, to become diverse and successful inhabitants of the land habitats of Earth.