Amaranth Globulin Polypeptide Heterogeneity

The polypeptides integrating amaranth globulin-p and 11S-globulin were characterized by two-dimensional electrophoresis, ion-exchange chromatography and RP-HPLC. All polypeptides exhibited charge and hydrophobic heterogeneity. Almost all acid (A, pI 5–7) and basic (B, pI 9–10) polypeptides were present in both globulins, and the same happened with the unprocessed M polypeptides with pI in the range of 7–7.5 which fits well with a sequence containing both the A and B polypeptides. There were other polypeptides only present in 11S-globulin, like some of 41 and 16 kDa, which might come from another precursor or be the products of a different processing of the propolypeptide. These results suggested that, although amaranth subunits from different subfamilies are interchangeable in different oligomers, some structural differences between them might affect the assembly of globulin molecules. Structural differences arising from this behavior could account for the different physicochemical properties of globulin molecules.     

Influence of the physical environment and conspecific aggression on the spatial arrangement of breeding grey seals

Understanding the habitat requirements of a species for breeding is essential for its conservation, particularly if the availability of suitable habitat is a limiting factor for population growth. This is postulated to be the case for grey seals, one of the more abundant marine apex predators in northern European waters. In common with similar studies that have investigated the habitat preferences of breeding grey seals, we use abiotic (topographical, climatological) attributes but, unlike previous work, we also incorporate behavioural variables, particularly the occurrence of aggressive interactions between females and the presence of neighbouring seals. We used two Generalized Additive Models (GAM) in a sequential and iterative fashion. The first model links the occurrence of aggression at particular points in the colony to local topography derived from a Geographical Information System (GIS), presence of neighbouring seal pups and the day of the breeding season. The output of this GAM is used as one of the explanatory variables in a GAM of daily variation in the spatial distribution of births. Although proximity of a birth site to a water source and the presence of neighbouring seal pups both had significant influences on the distribution of newborn pups over time and space, at the scale of the study site it was found that simple rules could predict pup distribution more efficiently than a complex individual-based simulation model.     

Broad-scale habitat use by red-legged partridge <Emphasis Type="Italic">(Alectoris rufa</Emphasis>) in a low-density area in northwestern Spain

We developed broad-scale habitat selection models for the distribution of red-legged partridge Alectoris rufa in a low-density area in northwestern Spain, the Baixa-Limia site of community importance (SCI). The fieldwork consisted of ground surveys in 1 × 1 km squares. For habitat selection analysis, we used a 2 × 2 km grid integrating the information obtained in the 1 × 1 km squares. As predictors we used environmental variables measured on digital 1:50,000 scale cartography using a geographical information system (GIS). The red-legged partridge was scarce in the study area. The logistic regression analysis carried out on data from the squares with probable and confirmed breeding included the area of scrubland and pastureland with a positive sign. Using the breeding index category (BIC) three variables produced a slightly positive response: area of scrubland and pastureland, length of border between scrublands and forests, and length of border between forests and dams. The difficulty for modelling the habitat selection of this species could be due to human activities (hunting, habitat loss, restocking of hunt species), and may have modified their habitat preferences. Furthermore, the occupation of suboptimal habitats would distort the real habitat preferences.     

Impact of urban fragmentation on the genetic structure of the eastern red-backed salamander

Urban development is a major cause of habitat loss and fragmentation. Few studies, however, have dealt with fragmentation in an urban landscape. In this paper, we examine the genetic structure of isolated populations of the eastern red-backed salamander (Plethodon cinereus) in a metropolitan area. We sampled four populations located on a mountain in the heart of Montréal (Québec, Canada), which presents a mosaic of forested patches isolated by roads, graveyards and buildings. We assessed the genetic structure of these populations using microsatellite loci and compared it to the genetic structure of four populations located in a continuous habitat in southern Québec. Our results indicate that allelic richness and heterozygosity are lower in the urban populations. Exact differentiation tests and pairwise F _ST also show that the populations found in the fragmented habitat are genetically differentiated, whereas populations located in the continuous habitat are genetically homogeneous. These results raise conservation concerns for these populations as well as for rare or threatened species inhabiting urban landscapes.     

MtDNA reveals strong genetic differentiation among geographically isolated populations of the golden brown mouse lemur, <Emphasis Type="Italic">Microcebus ravelobensis</Emphasis>

Microcebus ravelobensis is an endangered nocturnal primate endemic to northwestern Madagascar. This part of the island is subject to extensive human intervention leading to massive habitat destruction and fragmentation. We investigated the degree of genetic differentiation among remaining populations using mitochondrial control region sequences (479–482 bases). Nine populations were sampled from the hypothesized geographic range. The region is composed of three inter-river systems (IRSs). Samples were collected in three areas of continuous forests (CFs) and six isolated forest fragments (IFFs) of different sizes. We identified 27 haplotypes in 114 animals, with CFs and IFFs harbouring 5–6 and 1–3 haplotypes, respectively. All IFFs were significantly differentiated from each other with high Φ_ST values and sets of unique haplotypes. The rivers constitute significant dispersal barriers with over 82% of the molecular variation being attributed to the divergence among the IRSs. The data suggest a deep and so far unknown split within the rufous mouse lemurs of northwestern Madagascar. The limited data base and the lack of ecological and morphological data do not allow definite taxonomic classification at this stage. However, the results clearly indicate that M. ravelobensis consists of three evolutionary significant units, possibly cryptic species, which warrant urgent and separate conservation efforts.     

Le site Paléolithique supérieur de Yudinovo : résultats des recherches archéologiques des années 2004–2016

The Upper Palaeolithic site of Yudinovo is one of the reference sites, located in the Desna River Basin. Multidisciplinary field studies, organized by the Desna mission (MAE RAS) and conducted between 2004 and 2016, have changed the vision existed so far on the structure and character of the Yudinovo site as well as on the duration of its occupations. The researchers found an ancient ford used by mammoths and other big mammals to cross the river, and a water source was one of the main factors in explaining the location of the Yudinovo site. The site has been occupied in a cyclical way for stays of varied duration. It was frequented by Prehistoric Men during the different seasons, and periods of occupation were apparently of different duration. The stratigraphy of the Yudinovo site reveals two major episodes in the evolution of the site. The dating of the lower archaeological layer dates back to 15,000–13,500 BC. J.C., while the upper layer is attributed to the period of 12,500–12,000 BC. The lower layer, which was formed during the major episode of occupation of the site, is rather thin and shows the complex stratigraphic structure. Various areas of activities, evacuation structures, storage areas with mammoth bones are discovered. Some elements of the lower archaeological layer are perfectly correlated with different episodes of sporadic occupation.     

Double-exponential kinetics of binding and redistribution of the fluorescent dyes in cell membranes witness for the existence of lipid microdomains

New technique of detecting lateral heterogeneity of the plasma membrane of living cells by means of membrane-binding fluorescent dyes is proposed. The kinetics of dye incorporation into the membrane or its lateral diffusion inside the membrane is measured and decomposed into exponential components by means of the Maximum Entropy Method. Two distinct exponential components are obtained consistently in all cases for several fluorescent dyes, two different cell lines and in different types of experiments including spectroscopy, flow cytometry and fluorescence recovery after photobleaching. These components are attributed to the liquid-ordered and disordered phases in the plasma membrane of studied cells in their dynamic equilibrium.     

Effect of detection heterogeneity in occupancy‐detection models: an experimental test of time‐to‐first‐detection methods

Imperfect detection can bias estimates of site occupancy in ecological surveys but can be corrected by estimating detection probability. Time‐to‐first‐detection (TTD) occupancy models have been proposed as a cost–effective survey method that allows detection probability to be estimated from single site visits. Nevertheless, few studies have validated the performance of occupancy‐detection models by creating a situation where occupancy is known, and model outputs can be compared with the truth. We tested the performance of TTD occupancy models in the face of detection heterogeneity using an experiment based on standard survey methods to monitor koala Phascolarctos cinereus populations in Australia. Known numbers of koala faecal pellets were placed under trees, and observers, uninformed as to which trees had pellets under them, carried out a TTD survey. We fitted five TTD occupancy models to the survey data, each making different assumptions about detectability, to evaluate how well each estimated the true occupancy status. Relative to the truth, all five models produced strongly biased estimates, overestimating detection probability and underestimating the number of occupied trees. Despite this, goodness‐of‐fit tests indicated that some models fitted the data well, with no evidence of model misfit. Hence, TTD occupancy models that appear to perform well with respect to the available data may be performing poorly. The reason for poor model performance was unaccounted for heterogeneity in detection probability, which is known to bias occupancy‐detection models. This poses a problem because unaccounted for heterogeneity could not be detected using goodness‐of‐fit tests and was only revealed because we knew the experimentally determined outcome. A challenge for occupancy‐detection models is to find ways to identify and mitigate the impacts of unobserved heterogeneity, which could unknowingly bias many models.