Metric remote sensing experiments in preparation for Spacelab flights

Aerial and ground photographs of Wallis mountains and of Dolomiti di Cortina d'Ampezzo in Italy were made using spectrozonal emulsions and optical multichannel filters. A metric camera was used in the perspective of the first Spacelab flight aboard the space shuttle. Elementary forms of alpine geomorphology and ice or snow phenomena are detectable on these metric scenes

Tuning the reduction of graphene oxide nanoflakes differently affects neuronal networks in the zebrafish

The increasing engineering of biomedical devices and the design of drug-delivery platforms enriched by graphene-based components demand careful investigations of the impact of graphene-related materials (GRMs) on the nervous system. In addition, the enhanced diffusion of GRM-based products and technologies that might favor the dispersion in the environment of GRMs nanoparticles urgently requires the potential neurotoxicity of these compounds to be addressed. One of the challenges in providing definite evidence supporting the harmful or safe use of GRMs is addressing the variety of this family of materials, with GRMs differing for size and chemistry. Such a diversity impairs reaching a unique and predictive picture of the effects of GRMs on the nervous system. Here, by exploiting the thermal reduction of graphene oxide nanoflakes (GO) to generate materials with different oxygen/carbon ratios, we used a high-throughput analysis of early-stage zebrafish locomotor behavior to investigate if modifications of a specific GRM chemical property influenced how these nanomaterials affect vertebrate sensory-motor neurophysiology—exposing zebrafish to GO downregulated their swimming performance. Conversely, reduced GO (rGO) treatments boosted locomotor activity. We concluded that the tuning of single GRM chemical properties is sufficient to produce differential effects on nervous system physiology, likely interfering with different signaling pathways

An integrated 4249 marker FISH/RH map of the canine genome

BACKGROUND: The 156 breeds of dog recognized by the American Kennel Club offer a unique opportunity to map genes important in genetic variation. Each breed features a defining constellation of morphological and behavioral traits, often generated by deliberate crossing of closely related individuals, leading to a high rate of genetic disease in many breeds. Understanding the genetic basis of both phenotypic variation and disease susceptibility in the dog provides new ways in which to dissect the genetics of human health and biology. RESULTS: To facilitate both genetic mapping and cloning efforts, we have constructed an integrated canine genome map that is both dense and accurate. The resulting resource encompasses 4249 markers, and was constructed using the RHDF5000-2 whole genome radiation hybrid panel. The radiation hybrid (RH) map features a density of one marker every 900 Kb and contains 1760 bacterial artificial chromosome clones (BACs) localized to 1423 unique positions, 851 of which have also been mapped by fluorescence in situ hybridization (FISH). The two data sets show excellent concordance. Excluding the Y chromosome, the map features an RH/FISH mapped BAC every 3.5 Mb and an RH mapped BAC-end, on average, every 2 Mb. For 2233 markers, the orthologous human genes have been established, allowing the identification of 79 conserved segments (CS) between the dog and human genomes, dramatically extending the length of most previously described CS. CONCLUSIONS: These results provide a necessary resource for the canine genome mapping community to undertake positional cloning experiments and provide new insights into the comparative canine-human genome maps

Members of the Hyposoter didymator Ichnovirus repeat element gene family are differentially expressed in Spodoptera frugiperda

BACKGROUND: The abundance and the conservation of the repeated element (rep) genes in Ichnoviruses genomes suggest that this gene family plays an important role in viral cycles. In the Ichnovirus associated with the wasp Hyposoter didymator, named HdIV, 10 rep genes were identified to date. In this work, we report a relative quantitative transcription study of these HdIV rep genes in several tissues of the lepidopteran host Spodoptera frugiperda as well as in the H. didymator wasps. RESULTS: The data obtained in this work indicate that, in the early phases of infection (24 hours), HdIV rep genes each display different levels of transcripts in parasitized 2(nd )instar or HdIV-injected last instar S. frugiperda larvae. Only one, rep1, is significantly transcribed in female wasps. Transcript levels of the HdIV rep genes were found as not correlated to their copy number in HdIV genome. Our results also show that HdIV rep genes display different tissue specificity, and that they are primarily transcribed in S. frugiperda fat body and cuticular epithelium. CONCLUSION: This work is the first quantitative analysis of transcription of the ichnovirus rep gene family, and the first investigation on a correlation between transcript levels and gene copy numbers in Ichnoviruses. Our data indicate that, despite similar gene copy numbers, not all the members of this gene family are significantly transcribed 24 hours after infection in lepidopteran larvae. Additionally, our data show that, as opposed to other described HdIV genes, rep genes are little transcribed in hemocytes, thus suggesting that they are not directly associated with the disruption of the immune response but rather involved in other physiological alterations of the infected lepidopteran larva

Cyclotron resonance of extremely conductive 2D holes in high Ge content strained heterostructures

Cyclotron resonance has been observed in steady and pulsed magnetic fields from high conductivity holes in Ge quantum wells. The resonance positions, splittings and linewidths are compared to calculations of the hole Landau levels

Universal Code Equivalent of a Yeast Mitochondrial lntron Reading Frame Is Expressed into E. coli as a Specific Double Strand Endonuclease

International audienceThe intron of the mitochondrial21S rRNA gene of Sac-charomyces cerevisiae (rl intron) possesses a 235 codon long internal open reading frame (rl ORF) whose translation product determines the duplicative transposition of that intron during crosses between intron-plus strains (omega+) and intron-minus ones (omega-). Using site-directed mutagenesis, we have constructed a universal code equivalent of the rl ORF that, under appropriate promoter control, allows the overexpression in E. coli of a protein identical to the mitochondrial intron encoded "transposase". This protein exhibits a double strand endonuclease activity specific for the omega-site. This finding demonstrates , for the first time, the enzymatic activity of an intron encoded protein whose function is to promote the spreading of that intron by generating double strand breaks at a specific sequence within a gene

Modelización de una Prueba de Analogías Figurales con la Teoría de Respuesta al Ítem

The psychometric properties of a Figural Analogies Test are described within the framework of Item Response Theory. Thirty-six 2x2 matrix figures were constructed by using location, distortion and number rules. The sample included 499 psychology students from the University of Buenos Aires, 79% of whom were women. The 3-Parameter Logistic Model was used obtaining a highly satisfactory global fit at 5% (p = .47). Only 3 items did not fit the model. It had good overall discriminatory power (a: M = 1.02, SD = .33), a medium level of difficulty (b: M = -.03, SD = .63) and the c level was slightly lower than expected with six possible answers (c: M = .14, SD = .05). The conditions for modelling the test and possible disadvantages of the present study are discussed.Se detallan las propiedades psicométricas de una Prueba de Analogías Figurales desde el marco de la Teoría de Respuesta al Ítem. Se elaboraron 36 matrices de figuras de 2x2 utilizando reglas de emplazamiento, distorsión y número. Se contó con una muestra de 499 estudiantes de Psicología de la Universidad de Buenos Aires, 79% de los cuales fueron mujeres. Se utilizó el Modelo Logístico de 3 Parámetros logrando un ajuste global altamente satisfactorio al 5% (p = .47). Sólo 3 ítems del total no ajustaron al modelo. Existe una buena potencia discriminatoria general (a: M = 1.02; DT = .33), un nivel de dificultad medio (b: M = -.03; DT = .63) y un nivel de acierto por azar ligeramente inferior a lo esperable con 6 alternativas de respuesta (c: M = .14; DT = .05). Se discuten las condiciones para modelizar la Prueba y posibles desventajas del presente estudio

Bacterial rotary export ATPases are allosterically regulated by the nucleotide second messenger cyclic-di-GMP

The widespread second messenger molecule cyclic di-GMP (cdG) regulates the transition from motile and virulent lifestyles to sessile, biofilm-forming ones in a wide range of bacteria. Many pathogenic and commensal bacterial-host interactions are known to be controlled by cdG signaling. Although the biochemistry of cyclic dinucleotide metabolism is well understood, much remains to be discovered about the downstream signaling pathways that induce bacterial responses upon cdG binding. As part of our ongoing research into the role of cdG signaling in plant-associated Pseudomonas species, we carried out an affinity capture screen for cdG binding proteins in the model organism Pseudomonas fluorescens SBW25. The flagella export AAA+ ATPase FliI was identified as a result of this screen and subsequently shown to bind specifically to the cdG molecule, with a KD in the low micromolar range. The interaction between FliI and cdG appears to be very widespread. In addition to FliI homologs from diverse bacterial species, high affinity binding was also observed for the type III secretion system homolog HrcN and the type VI ATPase ClpB2. The addition of cdG was shown to inhibit FliI and HrcN ATPase activity in vitro. Finally, a combination of site-specific mutagenesis, mass spectrometry, and in silico analysis was used to predict that cdG binds to FliI in a pocket of highly conserved residues at the interface between two FliI subunits. Our results suggest a novel, fundamental role for cdG in controlling the function of multiple important bacterial export pathways, through direct allosteric control of export ATPase proteins

A gene-based radiation hybrid map of the gilthead sea bream Sparus aurata refines and exploits conserved synteny with Tetraodon nigroviridis

Background: Comparative teleost studies are of great interest since they are important in aquaculture and in evolutionary issues. Comparing genomes of fully sequenced model fish species with those of farmed fish species through comparative mapping offers shortcuts for quantitative trait loci (QTL) detections and for studying genome evolution through the identification of regions of conserved synteny in teleosts. Here a comparative mapping study is presented by radiation hybrid (RH) mapping genes of the gilthead sea bream Sparus aurata, a non-model teleost fish of commercial and evolutionary interest, as it represents the worldwide distributed species-rich family of Sparidae.Results: An additional 74 microsatellite markers and 428 gene-based markers appropriate for comparative mapping studies were mapped on the existing RH map of Sparus aurata. The anchoring of the RH map to the genetic linkage map resulted in 24 groups matching the karyotype of Sparus aurata. Homologous sequences to Tetraodon were identified for 301 of the gene-based markers positioned on the RH map of Sparus aurata. Comparison between Sparus aurata RH groups and Tetraodon chromosomes (karyotype of Tetraodon consists of 21 chromosomes) in this study reveals an unambiguous one-to-one relationship suggesting that three Tetraodon chromosomes correspond to six Sparus aurata radiation hybrid groups. The exploitation of this conserved synteny relationship is furthermore demonstrated by in silico mapping of gilthead sea bream expressed sequence tags (EST) that give a significant similarity hit to Tetraodon.Conclusion: The addition of primarily gene-based markers increased substantially the density of the existing RH map and facilitated comparative analysis. The anchoring of this gene-based radiation hybrid map to the genome maps of model species broadened the pool of candidate genes that mainly control growth, disease resistance, sex determination and reversal, reproduction as well as environmental tolerance in this species, all traits of great importance for QTL mapping and marker assisted selection. Furthermore this comparative mapping approach will facilitate to give insights into chromosome evolution and into the genetic make up of the gilthead sea bream