Lectin Binding to Radopholus citrophilus and R. similis Proteins

Lectin-binding glycoproteins in seven populations of two burrowing nematode sibling species were probed with five different biotinylated lectins on Western blots, and differences were correlated with nematode ability to parasitize citrus and to overcome citrus rootstock resistance. Banding patterns of molecular weight standards were fit best by an exponential decay function, and a predictive equation was used to estimate molecular weights (r² = 0.999). A band (131 kDa) that labeled with the lectin Concanavalin A (Con A) occurred in extracts from cuticles and egg shells of populations of Radopholus citrophilus that parasitize citrus. Wheat germ agglutin labeled a band (58 kDa) in aqueous homogenates of populations that reproduce in roots of citrus rootstock normally resistant to burrowing nematodes. The two sibling species R. citrophilus and R. similis were distinguished by a high molecular weight Con A-labeled band (608 kDa) from cuticle and egg shells. Probing blots with the lectin Limulus polyphemus agglutinin indicated that each population contained a band (12-16 kDa) specifically inhibited by the addition of 25 mM neuraminic acid, suggesting that glycoproteins with sialic acid moieties are present in burrowing nematodes.     

Factors affecting population density, group size and territory size of the European badger, Meles meles

This paper discusses the relationship between the distribution and biomass of the main prey of European badgers, Meles meles and the badgers group size, territory size and population density. The distribution of areas rich in earthworms, Lumbricus spp., is correlated with badger range size, whilst badger group size increases with the biomass of worms per badger territory and badger density increases with overall worm biomass. Regulation of badger density in an area is likely to take place through regulation of group size, in the absence of other factors such as persecution and lack of suitable sett-sites.     

Mendelian analysis of the organization of actin sequences in Physarum polycephalum

The genormic organization of the multiple actin DNA sequences in the lower eukaryote Physarum polycephalum was investigated by Mendelian mapping. Actin-homologous restriction endonuclease cleavage fragments detected by DNA blotting showed length polymorphisms when different strains were compared. These length polymorphisms were used as phenotypic markers for actin sequences in the genome. The meiotic assortment of the polymorphic restriction fragments was analysed, revealing four unlinked actin loci. The data for three-of the actin loci, ardB, C and D, are consistent with a single sequence or gene at each locus. The data for the other actin locus. ardA, is consistent with multiple linked actin sequences or genes.     

Cerebral Synaptic Transmission During Anoxia Is Protected by Creatine

Synaptic transmission in cerebral tissue fails very rapidly in the absence of oxygen; the metabolic basis for this is not known. We report here that the transmission failure in the guinea pig hippocampal slice can be delayed threefold by exposing the tissue to extracellular creatine (Cr) for 3 h. The improved survival is associated with an increase of tissue phosphocreatine (PCr) concentration. These data argue that the metabolic basis for synaptic transmission failure is a fall in tissue ATP concentrations. They also indicate a way to protect brain tissue against anoxic damage.     

Recovery of MAO-B enzyme activity after (-)deprenyl (selegiline) pretreatment, measured in vivo

The recovery of MAO-B activity after a single dose of 0.25 mg/kg s.c. (-)deprenyl was measured in rat, by following the time course of the changes in the PEA (phenyl-ethylamine)-induced hyperactivity. One hour after its administration (-)deprenyl enhanced both the PEA-induced locomotion and stereotypy, however, its effect on the latter was more marked. At 24 h and at later time-points only stereotype was enhanced. The results show that a single small dose of (-)deprenyl which selectively blocks MAO-B, causes a long-lasting inhibition of PEA metabolism, and the enzyme activity needs more than one week to restore completely.     

Recent origin,active speciation and dispersal for the lichen genus Nephroma (Peltigerales) in Macaronesia

Aim We reconstructed the phylogeny of the lichen genus Nephroma (Peltigerales) to assess the relationships of species endemic to Macaronesia. We estimated dates of divergences to test the hypothesis that the species arose in Macaronesia (neo‐endemism) versus the oceanic archipelagos serving as refugia for formerly widespread taxa (palaeo‐endemism). Location Cosmopolitan with a special focus on the archipelagos of the Azores, Madeira and the Canary Islands. Methods DNA sequences were obtained from 18 species for three loci and analysed using maximum parsimony, maximum likelihood and Bayesian inferences. Divergence dates were estimated for the internal transcribed spacer (ITS)‐based phylogeny using a relaxed molecular clock. Reconstruction of the ancestral geographical range was conducted using the Bayesian 50% majority rule consensus tree under a parsimony method. Results The backbone phylogenetic tree was fully supported, with Nephroma plumbeum as sister to all other species. Four strongly supported clades were detected: the Nephroma helveticum, the N. bellum, the N. laevigatum and the N. parile clades. The latter two share a common ancestor and each includes a widespread Holarctic species (N. laevigatum and N. parile, respectively) and all species endemic to Macaronesia. The data suggest a neo‐endemic origin of Macaronesian taxa, a recent range expansion from Macaronesia of both widespread species, a range expansion limited to the Mediteranean Basin and south‐western Europe for another taxon, and a long dispersal event that resulted in a speciation event in the western parts of North America. Main conclusions The Macaronesian endemic species belong to two sister clades and originated from a most recent common ancestor (MRCA) shared with one widely distributed taxon, either N. parile or N. laevigatum. Estimates of the mean divergence dates suggest that the endemics originated in the archipelagos after the rise of the volcanic islands, along with the ancestor to the now widespread species, which probably expanded their range beyond Macaronesia via long‐distance dispersal. This study provides the first phylogenetic evidence of Macaronesian neo‐endemism in lichenized fungi and provides support for the hypothesis that oceanic islands may serve as a source for the colonization of continents. However, further data are needed to properly assess the alternative hypothesis, namely colonization from western North America.