Biosilica-nanogold composite: Easy-to-prepare catalyst for soman degradation

A very fast single-step biosynthesis of gold nanoparticles (AuNPs) using algal cells of Mallomonas kalinae (MK) is introduced. The average particle size of crystalline AuNPs was approximately 10 nm. Subsequently, the catalytic activity of two systems - MK-biosilica scales and MK-biosilica scales with AuNPs - was compared with a control hydrolysis of soman (GD) performed in demineralized water. The kinetics of GD degradation was studied using a gas chromatography with mass detector (GC-MS) and solid-phase microextraction. The residual content of GD was 3.8% and 3.5% for both initial concentrations of GD (68 mu g mL(-1) and 340 mu g L-1, respectively) after 48 h of testing when nanogold was used as a catalyst. Experimental results confirmed the catalytic activity of biosynthesized AuNPs, as well as the role of biosilica itself in the degradation of GD.Web of Science12227126

Diversité et écologie des chrysophytes à écailles siliceuses (Synurophyceae, Chrysophyceae) dans le National Nature Monument Swamp et l'Étang Brehynsky, République Tchèque.

Les chrysophytes à écailles siliceuses (Synurophyceae et Chrysophyceae) forment un petit groupe de flagellées d\u27eau douce dans lequel les cellules sont recouverte par une enveloppe d\u27écailles dont la morphologie est caractéristique de l\u27espèce. Trente taxons ont été dénombrés lors d\u27une étude des bassins tourbeux du National Nature Monument Swamp et du plancton de l\u27étang de Brehynsky, République Tchèque. À côté d\u27espèces cosmopolites et largement distribuées, Mallomonas adamas et M. maculata présentent une distribution géographique inégale, et M. clavus, Synura lapponica et Chrysosphaerella longispina une distribution septentrionale tempérée. Mallomonas annulata, M. heterospina, M. paludosa, M. papillosa, M. calceolus, M. pumilio, Synura echinulata, S. lapponica et Chrysosphaerella longispina appartiennent à un groupe de taxons des eaux fraîches. Mallomonas multisetigera, M. ouradion, M. papillosa, Synura echinulata, S. sphagnicola et Paraphysomonas vestita sont capables de former des peuplements dominants dans des milieux extrêmement acides (pH 3.5-4.0). Mallomonas clavus, M. favosa, M. maculata, M. rasilis et Chrysosphaerella longispina ont été trouvées ici pour la première fois en République Tchèque.The silica-scaled chrysophytes (Synurophyceae and Chrysophyceae) are a small group of freshwater flagellates with cells enclosed within a morphologically species-specific scale case. Thirty taxa were found during an investigation of peaty pools in the National Nature Monument Swamp and the plankton of Brehynsky Pond, Czech Republic. Along with cosmopolitan and widely distributed species, Mallomonas adamas and M. maculata, which shows a patchy geographic distribution, and M. clavus, Synura lapponica and Chrysosphaerella longispina, which show a northern temperate distribution, were found. Mallomonas annulata, M. heterospina, M. paludosa, M. papillosa, M. calceolus, M. pumilio, Synura echinulata, S. lapponica and Chrysosphaerella longispina belong to a group of cool-water taxa. Mallomonas multisetigera, M. ouradion, M. papillosa, Synura echinulata, S. sphagnicola and Paraphysomonas vestita have an ability to form dominant populations in extremely acidic environments (pH 3.5-4.0). The species Mallomonas clavus, M. favosa, M. maculata, M. rasilis and Chrysosphaerella longispina are recorded here for the first time from the Czech Republic.</p

Morphological delineation and distribution patterns of four newly described species within the <i>Synura petersenii</i> species complex (Chrysophyceae, Stramenopiles)

<div><p>The <i>Synura petersenii</i> species complex represents a common, cosmopolitan and highly diverse taxon of autotrophic freshwater flagellates. In this paper, we describe and characterize four new species (<i>S. borealis</i>, <i>S. heteropora</i>, <i>S. hibernica</i> and <i>S. laticarina</i>) that have been identified during our extensive sampling of freshwater habitats in 15 European countries. Morphometric analyses of siliceous scales led to the significant phenotypic differentiation of all four newly described species, and their separation from other related species of the <i>S. petersenii</i> complex. Two of these newly described species (<i>S. hibernica</i> and <i>S. borealis</i>) can be clearly distinguished by characteristic large colonies consisting of elongated, lanceolate-shaped cells. Development of strongly elongated, narrow cells in <i>S. hibernica</i> could be explained by the adaptation of this species to oligotrophic conditions. Though morphologically distinct, <i>S. borealis</i> possesses an exceptionally high degree of genetic diversity, possibly indicating recent speciation and evolutionary diversification within this taxon. Three of the four newly described species exhibit restricted biogeographic distribution. The evolutionarily related <i>S. borealis</i> and <i>S. laticarina</i> occur only in Northern Europe, and seem to be adapted to colder areas. The most remarkable distribution pattern was observed for <i>S. hibernica</i>, which has a geographic distribution that is restricted to western Ireland.</p></div