Nymphal feeding habits of Perla madritensis Rambur 1842 (Plecoptera: Perlidae)

The diet of Perla madritensis, endemic species of the northern half of the Iberian Peninsula, is described for the first time by means of a study carried out in north-western Spain. As other species of the genus Perla, this taxon behaves mainly as predator, with Chironomidae, followed by Baetidae, being the most abundant prey in its gut. Shifts in diet composition were detected in relation to size in this species, with smaller prey being replaced by larger ones such as Simuliidae and Leptophlebiidae when the nymphs become larger.     

Vasopressin activates Akt/mTOR pathway in smooth muscle cells cultured in high glucose concentration

Mammalian target of rapamycin (mTOR) complex is a key regulator of autophagy, cell growth and proliferation. Here, we studied the effects of arginine vasopressin (AVP) on mTOR activation in vascular smooth muscle cells cultured in high glucose concentration.     

msap: a tool for the statistical analysis of methylation‐sensitive amplified polymorphism data

In this study msap, an R package which analyses methylation‐sensitive amplified polymorphism (MSAP or MS‐AFLP) data is presented. The program provides a deep analysis of epigenetic variation starting from a binary data matrix indicating the banding pattern between the isoesquizomeric endonucleases HpaII and MspI, with differential sensitivity to cytosine methylation. After comparing the restriction fragments, the program determines if each fragment is susceptible to methylation (representative of epigenetic variation) or if there is no evidence of methylation (representative of genetic variation). The package provides, in a user‐friendly command line interface, a pipeline of different analyses of the variation (genetic and epigenetic) among user‐defined groups of samples, as well as the classification of the methylation occurrences in those groups. Statistical testing provides support to the analyses. A comprehensive report of the analyses and several useful plots could help researchers to assess the epigenetic and genetic variation in their MSAP experiments. msap is downloadable from CRAN ( http://cran.r-project.org/ ) and its own webpage ( http://msap.r-forge.R-project.org/ ). The package is intended to be easy to use even for those people unfamiliar with the R command line environment. Advanced users may take advantage of the available source code to adapt msap to more complex analyses.     

Variability on microevolutionary and macroevolutionary scales: a review on patterns of morphological variation in Cnidaria Medusozoa

Members of Cnidaria Medusozoa are known for their wide morphological variation, which is expressed on many different levels, especially in different phases of the life cycle. Difficulties in interpreting morphological variations have posed many taxonomic problems, since intraspecific morphological variations are often misinterpreted as interspecific variations and vice-versa, hampering species delimitation. This study reviews the patterns of morphological variation in the Medusozoa, to evaluate how different interpretations of the levels of variation may influence the understanding of the patterns of diversification in the group. Additionally, we provide an estimate of the cryptic diversity in the Hydrozoa, based on COI sequences deposited in GenBank. Morphological variations frequently overlap between microevolutionary and macroevolutionary scales, contributing to misinterpretations of the different levels of variation. In addition, most of the cryptic diversity described so far for the Medusozoa is a result of previously overlooked morphological differences, and there is still great potential for discovering cryptic lineages in the Hydrozoa. We provide evidence that the number of species in the Medusozoa is misestimated and emphasize the necessity of examining different levels of morphological variations when studying species boundaries, in order to avoid generalizations and misinterpretations of morphological characters.     

Relation between light absorption measured by the quantitative filter technique and attenuation of <Emphasis Type="Italic">Chlorella fusca</Emphasis> cultures of different cell densities: application to estimate the absolute electron transport rate (ETR)

In order to estimate microalgal carbon assimilation or production of Chlorella fusca cultures based on electron transport rate (ETR) as in vivo chlorophyll a fluorescence, it is necessary to determine the photosynthetic yield and the absorbed quanta by measuring the incident irradiance and the fraction of absorbed light, i.e., absorptance or absorption coefficient in the photosynthetic active radiation (PAR) region of the spectra. Due to difficulties associated with the determination of light absorption, ETR is commonly expressed as relative units (rETR) although this is not a good estimator of the photosynthetic production since photobiological responses depend on the absorbed light. The quantitative filter technique (QFT) is commonly used to measure the absorbed quanta of cells retained on a filter (AbQ_f) as estimator of the absorbed quanta of cell suspensions (AbQ_s) determined by using integrating spheres. In this study, light attenuation of thin-layer cell suspensions is determined by using a measuring system designed to reduce the scattering. The light attenuation is related to the absorptance as the fraction of absorbed light by both indoor and outdoor C. fusca cultures of different cell densities. A linear relation between AbQ_f and AbQ_s (R ²?=?0.9902, p?<?0.01) was observed, AbQ_f?=?1.98?×?AbQ_s, being 1.98 an amplification factor to convert AbQ_s values into AbQ_f ones. On the other hand, depending on the culture system, the convenience of the use of the absorptance, light absorption or specific light absorption coefficient expressed per area (thin-layer cascade or flat panel cultivators), volume (cylindrical and tubular photobioreactors), or chlorophyll units (any type of cultivation system) is discussed. The procedure for the measurement of light absorption presented in this study for C. fusca could be applied in other phytoplankton groups. The absorbed quanta as determined in this study can be used to express absolute ETR instead of relative ETR, since the first one provides much more relevant photobiological information of microalgae culture systems.     

CONSTANS delays Arabidopsis flowering under short days

Long days (LD) promote flowering of Arabidopsis thaliana compared with short days (SD) by activating the photoperiodic pathway. Here we show that growth under very‐SD (3 h) or darkness (on sucrose) also accelerates flowering on a biological scale, indicating that SD actively repress flowering compared with very‐SD. CONSTANS (CO) repressed flowering under SD, and the early flowering of co under SD required FLOWERING LOCUS T (FT). FT was expressed at a basal level in the leaves under SD, but these levels were not enhanced in co. This indicates that the action of CO in A. thaliana is not the mirror image of the action of its homologue in rice. In the apex, CO enhanced the expression of TERMINAL FLOWER 1 (TFL1) around the time when FT expression is important to promote flowering. Under SD, the tfl1 mutation was epistatic to co and in turn ft was epistatic to tfl1. These observations are consistent with the long‐standing but not demonstrated model where CO can inhibit FT induction of flowering by affecting TFL1 expression.     

Large-scale evaluation of candidate genes identifies associations between VEGF polymorphisms and bladder cancer risk

Common genetic variation could alter the risk for developing bladder cancer. We conducted a large-scale evaluation of single nucleotide polymorphisms (SNPs) in candidate genes for cancer to identify common variants that influence bladder cancer risk. An Illumina GoldenGate assay was used to genotype 1,433 SNPs within or near 386 genes in 1,086 cases and 1,033 controls in Spain. The most significant finding was in the 5′ UTR of VEGF (rs25648, p for likelihood ratio test, 2 degrees of freedom = 1 × 10⁻⁵). To further investigate the region, we analyzed 29 additional SNPs in VEGF, selected to saturate the promoter and 5′ UTR and to tag common genetic variation in this gene. Three additional SNPs in the promoter region (rs833052, rs1109324, and rs1547651) were associated with increased risk for bladder cancer: odds ratio (95% confidence interval): 2.52 (1.06–5.97), 2.74 (1.26–5.98), and 3.02 (1.36–6.63), respectively; and a polymorphism in intron 2 (rs3024994) was associated with reduced risk: 0.65 (0.46–0.91). Two of the promoter SNPs and the intron 2 SNP showed linkage disequilibrium with rs25648. Haplotype analyses revealed three blocks of linkage disequilibrium with significant associations for two blocks including the promoter and 5′ UTR (global p = 0.02 and 0.009, respectively). These findings are biologically plausible since VEGF is critical in angiogenesis, which is important for tumor growth, its elevated expression in bladder tumors correlates with tumor progression, and specific 5′ UTR haplotypes have been shown to influence promoter activity. Associations between bladder cancer risk and other genes in this report were not robust based on false discovery rate calculations. In conclusion, this large-scale evaluation of candidate cancer genes has identified common genetic variants in the regulatory regions of VEGF that could be associated with bladder cancer risk.