Oogenesis in the egg-brooding frog Gastrotheca riobambae produces large oocytes with fewer nucleoli and low RNA content in comparison to Xenopus laevis

Abstract. The dissimilarities between oocytes of the eggbrooding frog, Gastrotheca riobambae , and Xenopus laevis suggest that oogenesis is modified according to the mode of reproduction. Oocytes of G. riobambae are large, yolky, and measure about 3 mm in diameter. In spite of the large oocyte size of Gastrotheca , the amplification of ribosomal genes, the number of nucleoli, and the amount of 18S and 28S rRNA are lower than in Xenopus oocytes. In Gastrotheca , the lower RNA content of oocytes is associated with a slow rate of development. A prolonged period of development is possible due to the protection given by the maternal pouch.     

Predominance of Th2 cytokines, CXC chemokines and innate immunity mediators at the mucosal level during severe respiratory syncytial virus infection in children

Profiling of immune mediators in both nasal and plasma samples is a common approach to the study of pathogenesis in respiratory viral infections. Nevertheless, mucosal immunity functions essentially independently from peripheral immunity. In our study, 27 immune mediators were profiled in parallel, in nasopharyngeal aspirates (NPAs) and plasma from 22 < 2 year-old children with a severe respiratory syncytial virus infection involving the lower respiratory tract, using a multiplex assay. NPAs from 22 children with innocent heart murmurs were used as controls. Differences in mediator concentrations between NPAs from patients and controls were assessed using the Mann-Whitney test. Ratios of innate/adaptive-immunity mediators, Th2/Th1-cytokines and CXC/CC-chemokines were calculated for NPAs and plasmas and differences were assessed using the Wilcoxon test. Associations mediators, severity and leukocyte counts were studied using the Spearman-Karber test. Results: increased levels of Th1 cytokines (IL-1beta, IL-2, IL-12p70, IFNgamma, TNFalpha), Th2 cytokines (IL-13, IL-4, IL-6, IL-10), chemokines (IP-10, IL-8, MIP1alpha, MIP-1beta), growth factors (FGFb, PDGFbb, GCSF) and IL-1RA, IL-17 were observed in patient NPAs in comparison to controls. In the relative comparisons between patient NPAs and plasmas, a predominance of innate immunity mediators, Th2 cytokines and CXC chemokines was found at the mucosal level. No association between the level of each mediator in NPAs and plasma was found. In plasma, PDGFbb, VEGF, MIP-1alpha, IL-8 correlated with severity; RANTES and IL-6 correlated with leukocyte counts. Conclusions: acute respiratory syncytial virus infection induces a relative predominance of innate-immunity mediators, Th2 cytokines and CXC chemokines in the mucosal compartment in infected children.     

The essential role of chemokines in the selective regulation of lymphocyte homing

Knowledge of lymphocyte migration has become a major issue in our understanding of acquired immunity. The selective migration of na?ve, effector, memory and regulatory T-cells is a multiple step process regulated by a specific arrangement of cytokines, chemokines and adhesion receptors that guide these cells to specific locations. Recent research has outlined two major pathways of lymphocyte trafficking under homeostatic and inflammatory conditions, one concerning tropism to cutaneous tissue and a second one related to mucosal-associated sites. In this article we will outline our present understanding of the role of cytokines and chemokines as regulators of lymphocyte migration through tissues.     

Population biology of <Emphasis Type="Italic">Kosteletzkya pentacarpos</Emphasis> (Malvaceae) in the Llobregat delta (Catalonia,NE of Spain)

Field experiments and wild population monitoring have been performed to study the population biology of the rare long-lived Kosteletzkya pentacarpos (Malvaceae) in the Llobregat delta (Catalonia, NE Spain). Field experiments explored the fate of seeds in soil at different depths, seedling emergence, and seedling survival, growth and flowering with and without canopy cover during the first 2 years of life. They also were used to ascertain the size-related pattern of seedling survivorship and flowering. Field data concerning mortality, growth and fecundity of adult plants were collected yearly in three wild populations for 7–9 years. In old adults (reproducing long before the beginning of the study), ANOVAR tests were performed to compare maximum diameter, total and fertile shoots, and viable seeds per plant between years and populations. New adults (starting flowering the first year of study or in subsequent years) were used to explore, using linear and polynomial regressions, the association of RGR and both total and fertile shoot production with (i) plant size (maximum basal diameter or its logarithm); (ii) plant age (years in adult stage); and (iii) plant age after removing the effect of size and year-to-year fluctuations. In this case, we examined the age-related pattern of the residuals obtained from the regressions with size and year. The study identified the following main demographic features of K. pentacarpos: (i) transient, shallow soil seed bank; (ii) shade tolerance of seedling emergence; (iii) canopy-facilitation of seedling survival and bolting during the first two years of life; (iv) size-related pattern for seedling survivorship but not flowering; (v) exclusive dependence on a fluctuating seed output for reproduction; (vi) rapid adult growth; and (vii) high adult longevity but (viii) rapid depletion of fecundity with age. Seed output was highly constrained by mining insects. The changing size-structure and the decreasing reproductive success of old adults in several populations suggest that K. pentacarpos might undergo a dynamics of population establishment and extinction in the Ricarda marshes. Because of fluctuating reproduction and the lack of a persistent seed bank, the conservation of standing adult populations appears to be a key factor to ensure the persistence of the species.     

No longer Demospongiae: Homoscleromorpha formal nomination as a fourth class of Porifera

Over the past few years, there has been growing interest among the sponge community in the phylogenetic position of the Homoscleromorpha (i.e. within or outside the class Demospongiae). Recent molecular analyses clearly show that the Homoscleromorpha forms a distinct clade separated from the Demospongiae and is composed of two families, Oscarellidae and Plakinidae. Within the currently more widely accepted hypothesis of a monophyletic Porifera, we formally propose here to raise Homoscleromorpha to the class rank (the fourth one). We, therefore, provide a definition and a formal diagnosis. In the supplementary materials, we also present an alternative classification of the Homoscleromorpha, following the PhyloCode.     

Identification of Akt-independent Regulation of Hepatic Lipogenesis by Mammalian Target of Rapamycin (mTOR) Complex 2

Mammalian target of rapamycin complex 2 (mTORC2) is a key activator of protein kinases that act downstream of insulin and growth factor signaling. Here we report that mice lacking the essential mTORC2 component rictor in liver (Lrictor(KO)) are unable to respond normally to insulin. In response to insulin, Lrictor(KO) mice failed to inhibit hepatic glucose output. Lrictor(KO) mice also fail to develop hepatic steatosis on a high fat diet and manifest half-normal serum cholesterol levels. This is accompanied by lower levels of expression of SREBP-1c and SREBP-2 and genes of fatty acid and cholesterol biosynthesis. Lrictor(KO) mice had defects in insulin-stimulated Akt Ser-473 and Thr-308 phosphorylation, leading to decreased phosphorylation of Akt substrates FoxO, GSK-3β, PRAS40, AS160, and Tsc2. Lrictor(KO) mice also manifest defects in insulin-activated mTORC1 activity, evidenced by decreased S6 kinase and Lipin1 phosphorylation. Glucose intolerance and insulin resistance of Lrictor(KO) mice could be fully rescued by hepatic expression of activated Akt2 or dominant negative FoxO1. However, in the absence of mTORC2, forced Akt2 activation was unable to drive hepatic lipogenesis. Thus, we have identified an Akt-independent relay from mTORC2 to hepatic lipogenesis that separates the effects of insulin on glucose and lipid metabolism.     

Accounting for transportation impacts in the environmental assessment of waste management plans

Background, aim, and scope  Many recent studies on waste management have described in detail the potential impacts of recycling and final treatment of municipal waste. In public debates, the attention has also been focused on the choice of final disposal technologies (e.g. landfilling vs. incineration). However, a comprehensive assessment of the impacts of waste collection and transport was still lacking. In the present study, we use LCA to evaluate the potential impact of the provincial waste management plan of Varese (northern Italy). Particular attention is devoted to the estimation of environmental impacts generated during waste transport. Materials and methods  A detailed Life Cycle Inventory was built for the transportation phase, based on primary data collected by interviewing the agencies involved in waste collection. To model the recycling and final disposal phase we relied on the BUWAL 250 database. Impacts were evaluated with the Eco-Indicator 99 method in its egalitarian formulation. Results  The results of our analysis reveal that the major potential impacts of the plan are associated with waste collection and transport. These impacts are partially compensated by reduced resource consumption through recycling and energy recovery through incineration. Discussion  The outputs of the LCIA were compared with those obtained by using other ecoindicators (Eco-Indicator 99 hierarchist and individualist, CML2, EPS2000). Although not comparable on a quantitative basis, they are qualitatively consistent. Conclusions  Neglecting the effects of collection and transport might result in a severe underestimation of the environmental impacts of a waste management system, especially as refers to depletion of fossil fuels, emission of respiratory inorganics and climate change. To reduce the environmental impact of waste management systems, an accurate optimisation of waste transport is required. Recommendations and perspectives  Effective waste management planning requires the explicit inclusion of waste collection and transport when comparing alternative management policies.     

Design of a Brassica rapa core collection for association mapping studies

A Brassica rapa collection of 239 accessions, based on two core collections representing different morphotypes from different geographical origins, is presented and its use for association mapping is illustrated for flowering time. We analyzed phenotypic variation of leaf and seed pod traits, plant architecture, and flowering time using data collected from three field experiments and evaluated the genetic diversity with a set of SSR markers. The Wageningen University and Research Centre (WUR) and the Vavilov Research Institute of Plant Industry (VIR) core collections had similar representations of most morphotypes, as illustrated by the phenotypic and genetic variation within these groups. The analysis of population structure revealed five subgroups in the collection, whereas previous studies of the WUR core collection indicated four subgroups; the fifth group identified consisted mainly of oil accessions from the VIR core collection, winter oils from Pakistan, and a number of other types. A very small group of summer oils is described, that is not related to other oil accessions. A candidate gene approach was chosen for association mapping of flowering time with a BrFLC1 biallelic CAPS marker and a BrFLC2 multiallelic SSR marker. The two markers were significantly associated with flowering time, but their effects were confined to certain morphotypes and (or) alleles. Based on these results, we discuss the optimal design for an association mapping population and the need to fix the heterogeneous accessions to facilitate phenotyping and genotyping.     

Gender-associated differences of perforin polymorphisms in the susceptibility to multiple sclerosis

The granule-dependent exocytosis pathway is an important mechanism to induce apoptosis by CD8(+) T cells and NK cells and involves lytic molecules such as perforin. In the current study, we investigated the perforin 1 gene (PRF1) as a candidate for multiple sclerosis (MS) susceptibility in the Spanish population. We genotyped three PRF1 single nucleotide polymorphisms (rs885822, rs10999426, and rs3758562) in 420 patients with MS and 512 controls. Associations of PRF1 polymorphisms with the disease were restricted to male patients with MS, and the finding was consistently observed at the allele, genotype, and haplotype levels. Gender-associated differences were validated in an additional replication cohort comprised of 292 MS cases and 300 controls. In addition, we identified minor risk haplotypes strongly associated with male patients having primary progressive MS (PPMS). Further characterization of male patients with PPMS carrying the risk haplotypes by means of gene expression microarrays revealed overrepresentation of the cell killing gene ontology category among downregulated genes in these patients compared with male patients with PPMS carrying protective haplotypes. Moreover, PRF1 mRNA expression levels were significantly lower in patients with risk haplotypes, and changes in perforin protein expression by CD8(+) T cells mirrored those observed in gene expression. These findings suggest a gender dimorphism in the PRF1 association with MS and point to the presence of a generalized defect in the expression of genes that code for proteins involved in cell killing in a subgroup of male patients with PPMS.