International audienceSargassum muticum, an invasive brown macroalga presently distributed along European Atlantic coasts from southern Portugal to the south coast of Norway, was studied on a large geographical scale for its production of phenolic compounds with potential industrial applications and their chemical and biological activities. S. muticum can produce high biomass in Europe, which could be exploited to supply such compounds. S. muticum was collected in Portugal, Spain, France, Ireland and Norway (three sites/country) to examine the effect of the latitudinal cline and related environmental factors. Assays focused particularly on polyphenols and their activities. Crude acetone-water extracts were purified using solid phase extraction (SPE) and antioxidant and antimicrobial activities of crude extracts and semi-purified fractions measured. Total phenolic content was assessed by colorimetric Folin-Ciocalteu assay and reactive oxygen species activities by 2,2-diphenyl-1-picrylhydrazyl, reducing power, β-carotene bleaching method and xanthine oxidase assay. Antibacterial activities were tested on terrestrial and marine strains to evaluate potential use in biomedical and aquaculture fields. Purified active phlorotannins, isolated by SPE, were identified using NMR. Phenolic contents differ clearly among countries and among sites within countries. Quality did not change between countries, however, although there were some slight differences in phlorethol type. Additionally, some fractions, especially from the extreme north and south, were very active. We discuss this in relation to environmental conditions and the interest of these compounds. S. muticum represents a potential natural source of bioactive compounds and its collection could offer an interesting opportunity for the future management of this species in Europe

Quantifying relationships between genetic variation and population viability is important from both basic biological and applied conservation perspectives, yet few populations have been monitored with both long‐term demographic and population genetics approaches. To empirically test whether and how genetic variation and population dynamics are related, we present one such paired approach. First, we use eight years of historical demographic data from five populations of Boechera fecunda (Brassicaceae), a rare, self‐compatible perennial plant endemic to Montana, USA, and use integral projection models to estimate the stochastic population growth rate (λS) and extinction risk of each population. We then combine these demographic estimates with previously published metrics of genetic variation in the same populations to test whether genetic diversity within populations is linked to demographic performance. Our results show that in this predominantly inbred species, standing genetic variation and demography are weakly positively correlated. However, the inbreeding coefficient was not strongly correlated with demographic performance, suggesting that more inbred populations are not necessarily less viable or at higher extinction risk than less inbred populations. A contemporary re‐census of these populations revealed that neither genetic nor demographic parameters were consistently strong predictors of current population density, although populations showing lower probabilities of extinction in demographic models had larger population sizes at present. In the absence of evidence for inbreeding depression decreasing population viability in this species, we recommend conservation of distinct, potentially locally adapted populations of B. fecunda rather than alternatives such as translocations or reintroductions.

SYNOPSIS. The fine structure of the eugregarine Lankesteria culicis from the larvae of the mosquito Aedes aegypti was examined by light and electron microscopy and compared with that of other gregarines. The cell organelles found in L. culicis included a nucleus, mitochondria, Golgi‐complexes, endoplasmic reticulum, vesicles, droplets, granules and lipid bodies. The surface of L. culicis was composed of a highly differentiated membrane‐cortex, differing slightly from that of other eugregarines. This complex was limited by a unit membrane, the plasmelemma, and underlying cortical laminae which appeared to be composed of several layers. The homogeneous electrondense layer present in Pyxinoides balani was greatly diminished or absent in L. culicis. A series of laminar folds supported by ground substance and longitudinal subpellicular fibrils gave the organism's surface a ridge‐like appearance. Permanent cytostome‐like openings in the surface, which appeared to be supported by a narrow band of thickened cortex, were present as specializations of the surfacemembrane complex. The structural composition of the parasite appeared quite striking in that it was made up almost entirely of vesicles, granules, and droplets which were absent only in the area of the protomerite. The mitochondria were usually found just beneath the surface or near the nucleus. Mitochondria were also seen in the region of demarcation between the protomerite and deutomerite.