Spauligodon aloisei n. sp. (Nematoda: Pharyngodonidae) parasite of Podarcis sicula (Reptilia: Lacertidae) from Italy

A new species of an oxyurid nematode is described from the large intestine of the lacertid lizard Podarcis sicula (Rafinesque. 1810) (Reptilia: Lacertidae) from Italy. Spauligodon aloisei n. sp. differs from other species of the genus by a combination of morphological and metrical characters, including a spined tail in males and females, absence of a spicule in males, arrangement of the last pair of the male caudal papillae, vulva location, and egg morphology. The species most similar to S. aloisei n. sp. is Spauligodon caspius Annayev, 1987, described from Tenuidactylus (=Gymnodactylus) caspius in Turkmenistan. Tail length and location of the excretory pore and vulvar opening separate S. caspius from S. aloisei n. sp. This article increases the number of species of this genus from reptiles in the Paleartic Realm to 19.     

Genetic determinants of variation in the plasma levels of the C4b-binding protein (C4BP) in Spanish families

The C4b-binding protein (C4BP) is a plasma glycoprotein implicated in the homeostasis of the complement and coagulation systems. It is composed of two polypeptides (alpha and beta), which form three plasma oligomers with different subunit compositions (alpha(7)beta(1), alpha(7)beta(0), and alpha(6)beta(1)). The beta chain-containing C4BP isoforms (C4BPbeta(+)isoforms) bind and inactivate protein S (PS), downregulating the activated protein C (APC)-dependent anticoagulatory pathway. Because PS deficiency is associated with recurrent thrombosis, it has been suggested that increased levels of C4BPbeta(+)isoforms might diminish the free PS plasma level, affecting the risk of developing thromboembolism. Previous work has tested this hypothesis, but no definitive conclusions were reached, mostly because nothing is known about the factors influencing the high variability in C4BP plasma levels in humans. As a part of the GAIT project, using variance component analysis, this work provides the first estimation of the relative contributions of genetic and environmental influences on the plasma levels of total C4BP and C4BPbeta(+)isoforms. Plasma levels of total C4BP and C4BPbeta(+)isoforms showed strong evidence of genetic regulation (heritability 37.7% and 42.5%, respectively). They were also affected by age, smoking, and exogenous sex hormones. Our results constitute the first step in localizing and evaluating potential quantitative trait loci that affect the plasma levels of C4BP and C4BPbeta(+). Furthermore, analysis of phenotypic and genetic correlations between C4BPbeta(+)plasma levels and the components of the APC anticoagulatory pathway (total PS, free PS, functional PS, and functional PC) suggests a genetic co-regulation of the proteins. These observations might have important implications in the individual susceptibility to thrombotic disease.     

Sip,an integrase protein with excision,circularization and integration activities,defines a new family of mobile Staphylococcus aureus pathogenicity islands

We report the complete sequence of Staphylococcal pathogenicity island bovine 2 (SaPIbov2), encoding the biofilm-associated protein Bap. SaPIbov2 contains 24 open reading frames, including sip, which encodes a functional staphylococcal integrase protein. SaPIbov2 is bordered by 18 bp direct repeats. The integration site into the chromosome lies at the 3' end of a gene encoding GMP synthase. SaPIbov2 has extensive similarity to previously described pathogenicity islands of Staphylococcus aureus. The principal difference is that toxin genes present in the other pathogenicity islands are exchanged for a transposon-like element that carries the bap gene and genes encoding an ABC transporter and a transposase. Also, SaPIbov2 can be excised to form a circular element and can integrate site-specifically and RecA-independently at a chromosomal att site in a Sip-dependent manner. This was demonstrated both in S. aureus and with plasmid substrates ectopically in Escherichia coli. Thus, SaPIbov2 encodes a functional recombinase of the integrase family that promotes element excision and insertion/integration. In addition, we demonstrated that the presence of SaPIbov2 facilitated the persistence of S. aureus in an intramammary gland infection model. Finally, different bovine isolates of S. aureus were found to carry islands related to SaPIbov2, suggesting the existence of a family of related pathogenicity islands.     

Determination of the topography and biometry of chlorosomes by atomic force microscopy

Isolated chlorosomes of several species of filamentous anoxygenic phototrophic bacteria (FAPB) and green sulfur bacteria (GSB) were examined by atomic force microscopy (AFM) to characterize their topography and biometry. Chlorosomes of Chloroflexus aurantiacus, Chloronema sp., and Chlorobium (Chl.) tepidum exhibited a smooth surface, whereas those of Chl. phaeobacteroides and Chl. vibrioforme showed a rough one. The potential artifactual nature of the two types of surfaces, which may have arisen because of sample manipulation or AFM processing, was ruled out when AFM images and transmission electron micrographs were compared. The difference in surface texture might be associated with the specific lipid and polypeptide composition of the chlorosomal envelope. The study of three-dimensional AFM images also provides information about the size and shape of individual chlorosomes. Chlorosomal volumes ranged from ca. 35000 nm³ to 247000 nm³ for Chl. vibrioforme and Chl. phaeobacteroides, respectively. The mean height was about 25 nm for all the species studied, except Chl. vibrioforme, which showed a height of only 14 nm, suggesting that GSB have 1–2 layers of bacteriochlorophyll (BChl) rods and GFB have 4. Moreover, the average number of BChl molecules per chlorosome was estimated according to models of BChl rod organisation. These calculations yielded upper limits ranging from 34000 BChl molecules in Chl. vibrioforme to 240000 in Chl. phaeobacteroides, values that greatly surpass those conventionally accepted.This revised version was published online in October 2005 with corrections to the Cover Date.     

Effects of putrescine accumulation in tobacco transgenic plants with different expression levels of oat arginine decarboxylase

Arginine decarboxylase (ADC; EC 4.1.1.19) is a key enzyme in one of the two possible ways to synthesize putrescine (Put) in plants. In previous work ( Masgrau et al. 1997 ), we observed an altered phenotype (growth inhibition, leaf chlorosis and necrosis) in tobacco transgenic plants ( Nicotiana tabacum L. var. Wisconsin-38) containing the oat ADC cDNA under the control of a tetracycline inducible promoter, the severity of which was correlated with Put content. Now we have analysed the T₂ generation of a selected transgenic line (line 52), which in previous generations was characterized by presenting a moderate increase in ADC activity and polyamine levels, but no phenotype alterations. Studying two selected individuals, one with a high expression level of the transgene and the other with a moderate expression level, we demonstrate that only the one with increased polyamine content displays the altered (toxic) phenotype. The possible causes of toxicity have been analysed. The results suggest that either Put or its oxidation products, via diamine oxidase (DAO; EC 1.4.3.6), are the responsible factors for the deleterious effects observed in the transgenic plants.     

Quantified distribution of diatoms during the stratified [2pt] period of Boadella reservoir

We collected data and samples, from June to November of 1999 and 2000, to in situ quantify the abundance of phytoplankton in Boadella reservoir. Samples were taken at different stations along the reservoir and diatoms were persistent in the epilimnion and were the main phytoplankton component, with a peak of abundance up to 5 10⁵ particles ml^–1. The diatom growth during the initiation of the summer bloom was high in the reservoir upstream concurrent with maximum Chlorophyll a concentrations. A delay in the onset of the diatom bloom, together with lower values of the volume concentration, was found in 1999 compared to the results in 2000 and was attributed to the different stratification of the reservoir as a result of meteorological conditions. The diatom population sank from the epilimnion by sedimentation and formed aggregates that accumulated at the bottom of the epilimnion. Sedimentation to the hypolimnion occurred at the end of the bloom, where peaks of Chlorophyll a were found.     

Large-scale environmental correlates of forest tree distributions in Catalonia (NE Spain)

Aim To explore the environmental correlates of tree species distributions in Catalonia according to the chorological status of the species. Location The study area is the region of Catalonia, in north‐eastern Spain. Methods We used presence‐absence data for 24 species, sampled in random plots distributed throughout forests of Catalonia. A climate model for the Catalonia region provided environmental variables. We used classification tree analysis to explore the environmental correlates of the realized niches of tree species. The predictive accuracy of the models was assessed using the ROC curve approach. Potential distribution maps of tree species were generated for the whole Catalonia region. Results Models were ranked from low to high accuracy for the 24 species. Differences in accuracy among species were related to the chorological status of species. Zonal species, or species at the core of their range (Mediterranean and Sub‐Mediterranean species), were generally well predicted, while extrazonal species, or species at the edge of their range, were predicted only moderately well. Mediterranean species distributions showed good correlations with extreme temperatures and annual precipitation. Main conclusions The above trends confirmed the difficulty of identifying the realized niche of species at the edges of their ranges. In contrast, Mediterranean and Sub‐Mediterranean species, which were at the core of their range, were well‐predicted, confirming the importance of extremes of temperature and annual precipitation as effective surrogates for variables having more direct physiological roles in limiting the ability of plants to survive and grow. Maps of potential tree distributions allowed us to define suitable habitats and to highlight areas where species have been planted outside their natural distribution.     

The Position of Arthropods in the Animal Kingdom: A Search for a Reliable Outgroup for Internal Arthropod Phylogeny

Morphological evidence for the phylogeny of the animal kingdom has been discussed by numerous authors. DNA sequencing and phylogenetic methods for analyzing these data are alternative approaches to animal phylogeny, but the phenomenon of long branch attraction and poor taxonomic sampling have caused misinterpretations of metazoan relationships. Here we report a cladistic approach to metazoan evolution including 133 18S rDNA sequences of 31 animal phyla. Despite the difficulties associated with analyzing large data sets, our data suggest that the Bilateria and Protostomia are monophyletic. The internal phylogeny of the protostomes is divided into two main clades. One clade includes the classical protostome worms (annelids, sipunculans, echiurans, pogonophorans, and vestimentiferans), mollusks, nemerteans, “lophophorates,” platyhelminths, rotiferans, and acanthocephalans, although the internal resolution of the clade is very low. The second clade includes arthropods and other molting animals: tardigrades, onychophorans, nematodes, nematomorphans, kinorhynchs, and priapulans. The arthropods and related phyla lack a ciliated larvae, lack a multiciliate (locomotory) epithelium, and share many features, notably, a reduced coelomic cavity and the presence of a cuticle which molts. The use of these outgroups within the molting clade to root arthropod phylogenies is recommended instead of using annelids or other spiralians. The data are quite conclusive in those phyla with a good taxonomic sampling (i.e., platyhelminths and arthropods).     

Nitrate reductase in cotyledons of cucumber seedlings as affected by nitrate, phytochrome and calcium

Regulation by the active form of phytochrome (P_FR) and the effect of Ca²⁺ was examined with nitrate reductase (NR) in etiolated cucumber ( Cucumis sativus cv. Beilpuig). Nitrate reductase activity (NRA) was studied in excised cotyledons of cucumber seedlings grown in distilled water and in darkness for seven days at 24 ± 0.5°C. All experiments were performed in the dark and a dim green safelight was used during analyses. In etiolated cucumber cotyledons NRA was induced by nitrate and a brief irradiation (15 min) with red light (R) resulted in 62% increase in NRA. This effect was nullified when R was followed immediately by a brief (5 min) far-red light (FR). NRA also showed a semidian (12 h) rhythmicity. Both P_FR, and nitrate effects were age dependent. Calcium seemed to be involved since the phytochrome effect was only observed when calcium was supplied in the external solution. The effect of R on NRA depended on the period of calcium nitrate incubation. An external supply of calcium ionophore mimicked the effect of R and, if supplied to R-irradiated cotyledons, produced a higher NR level than that caused by R alone. This suggested that intracellular free calcium was involved.     

Determination of the intrinsic fermentation kinetics of Saccharomyces cerevisiae cells immobilized in Ca-alginate beads and observations on their growth

Continuous fermentation experiments in a well-stirred fermentor with Saccharomyces cerevisiae cells immobilized in Ca-alginate beads of small diameter (approx. 1 mm) have been performed in order to discover their intrinsic fermentation kinetics, and compare them to the fermentation kinetics for free cells, by fitting both sets of results to the same model. The results show similar kinetic parameters for free and immobilized cells. The changes in cell concentration inside the beads and microscopical observations of transverse sections throughout the experiments, allowed discernment of two different scenarios of cell growth inside the beads: low cell density and fully developed growth. Correspondence to: F. Gòdia