Genetic diversity in Spanish donkey breeds using microsatellite DNA markers

Genetic diversity at 13 equine microsatellite loci was compared in five endangered Spanish donkey breeds: Andaluza, Catalana, Mallorquina, Encartaciones and Zamorano-Leonesa. All of the equine microsatellites used in this study were amplified and were polymorphic in the domestic donkey breeds with the exception of HMS1, which was monomorphic, and ASB2, which failed to amplify. Allele number, frequency distributions and mean heterozygosities were very similar among the Spanish donkey breeds. The unbiased expected heterozygosity (H_E) over all the populations varied between 0.637 and 0.684 in this study. The low G_ST value showed that only 3.6% of the diversity was between breeds (P < 0.01). Significant deviations from Hardy-Weinberg equilibrium were shown for a number of locus-population combinations, except HMS5 that showed agreement in all analysed populations. The cumulative exclusion probability (PE) was 0.999 in each breed, suggesting that the loci would be suitable for donkey parentage testing. The constructed dendrogram from the D_A distance matrix showed little differentiation between Spanish breeds, but great differentiation between them and the Moroccan ass and also with the horse, used as an outgroup. These results confirm the potential use of equine microsatellite loci as a tool for genetic studies in domestic donkey populations, which could also be useful for conservation plans.     

Expression of canonical SOS genes is not under LexA repression in Bdellovibrio bacteriovorus

The here-reported identification of the LexA-binding sequence of Bdellovibrio bacteriovorus, a bacterial predator belonging to the delta-Proteobacteria, has made possible a detailed study of its LexA regulatory network. Surprisingly, only the lexA gene and a multiple gene cassette including dinP and dnaE homologues are regulated by the LexA protein in this bacterium. In vivo expression analyses have confirmed that this gene cassette indeed forms a polycistronic unit that, like the lexA gene, is DNA damage inducible in B. bacteriovorus. Conversely, genes such as recA, uvrA, ruvCAB, and ssb, which constitute the canonical core of the Proteobacteria SOS system, are not repressed by the LexA protein in this organism, hinting at a persistent selective pressure to maintain both the lexA gene and its regulation on the reported multiple gene cassette. In turn, in vitro experiments show that the B. bacteriovorus LexA-binding sequence is not recognized by other delta-Proteobacteria LexA proteins but binds to the cyanobacterial LexA repressor. This places B. bacteriovorus LexA at the base of the delta-Proteobacteria LexA family, revealing a high degree of conservation in the LexA regulatory sequence prior to the diversification and specialization seen in deeper groups of the Proteobacteria phylum.     

COX-2 Inhibition Combined with Radiation Reduces Orthotopic Glioma Outgrowth by Targeting the Tumor Vasculature

Cyclooxygenase 2 (COX-2) inhibitors have been shown to enhance tumor''s response to radiation in several animal models. The strong association of COX-2 and angiogenesis suggests that the tumor vasculature may be involved in this process. The current study investigated whether treatment with the COX-2 inhibitor E-6087 could influence response to local radiation in orthotopically growing murine gliomas and aimed to analyze the involvement of the tumor vasculature. GL261 glioma cells were injected into the cerebrum of C57bl/6 mice. From day 7 after tumor cell injection, mice were treated with COX-2 inhibitor at 50 mg/kg i.p. every third day. Radiation consisted of three fractions of 2 Gy given daily from day 9 to day 11. Mice were killed at day 21. The COX-2 inhibitor significantly enhanced the response to radiation, reducing mean volume to 32% of tumors treated with radiation only. The combination treatment neither increased apoptosis of tumor cells or stromal cells nor affected tumor microvascular density. In vitro, E-6087 and its active metabolite did not affect clonogenic survival of GL261 cells or human umbilical vein endothelial cell after radiation. In vivo, however, there was a nonsignificant increase in Angiopoietin (Ang)-1 and Tie-2 mRNA levels and a decrease of Ang-2 mRNA levels after combination treatment. These changes coincided with a significant increase in α-smooth muscle actin-positive pericyte coverage of tumor vessels. In conclusion, the antitumor effect of radiation on murine intracranial glioma growth is augmented by combining with COX-2 inhibition. Our findings suggest an involvement of the tumor vasculature in the observed effects.     

Effects of seed ingestion and herbivory by waterfowl on seedling establishment: a field experiment with wigeongrass Ruppia maritima in Doñana,south-west Spain

The ingestion of seeds by vertebrates usually affects the viability and/or germination rate of seeds. Increases in germination rate following passage through the vertebrate gut have often been assumed to be favourable for seedling survival and plant fitness, but this assumption has never been tested experimentally. Given that numbers of herbivorous waterfowl are higher in winter in Mediterranean wetlands, herbivory pressure there will be higher for early growing plants. In a factorial experiment we investigated the effects of seed ingestion by ducks (shoveler, Anas clypeata) on the survival of wigeongrass Ruppia maritima seedlings in the field in Doñana (south-west Spain), under differing exposures to herbivory by waterfowl and fish. We planted ingested and non-ingested seeds in December, using exclosures to protect half of them from herbivores. When they were protected inside exclosures, there was no difference between ingested and non-ingested seeds in the number of plants that survived until June-July. However, fewer plants survived from ingested seeds when exposed to natural levels of herbivory because they were exposed for longer than plants germinating from non-ingested seeds. In conclusion, increases in germination rate after ingestion are not necessarily beneficial for the plant, and the final outcome depends on complex interactions with other factors such as herbivore abundance.     

Using unmanned aerial vehicle‐based multispectral,RGB and thermal imagery for phenotyping of forest genetic trials: A case study in Pinus halepensis

The assessment of genetic differentiation in functional traits is fundamental towards understanding the adaptive characteristics of forest species. While traditional phenotyping techniques are costly and time‐consuming, remote sensing data derived from cameras mounted on unmanned aerial vehicles (UAVs) provide potentially valid high‐throughput information for assessing morphophysiological differences among tree populations. In this work, we test for genetic variation in vegetation indices (VIs) and canopy temperature among populations of Pinus halepensis as proxies for canopy architecture, leaf area, photosynthetic pigments, photosynthetic efficiency and water use. The interpopulation associations between vegetation properties and above‐ground growth (stem volume) were also assessed. Three flights (July 2016, November 2016 and May 2017) were performed in a genetic trial consisting of 56 populations covering a large part of the species range. Multispectral (visible and near infrared wavelengths), RGB (red, green, blue) and thermal images were used to estimate canopy temperature and vegetation cover (VC) and derive several VIs. Differences among populations emerged consistently across flights for VC and VIs related to leaf area, indicating genetic divergence in crown architecture. Population differences in indices related to photosynthetic pigments emerged only in May 2017 and were probably related to a contrasting phenology of needle development. Conversely, the low population differentiation for the same indices in July 2016 and November 2016 suggested weak interpopulation variation in the photosynthetic machinery of mature needles of P. halepensis. Population differences in canopy temperature found in July 2016 were indicative of variation in stomatal regulation under drought stress. Stem volume correlated with indices related to leaf area (positively) and with canopy temperature (negatively), indicating a strong influence of canopy properties and stomatal conductance on above‐ground growth at the population level. Specifically, a combination of VIs and canopy temperature accounted for about 60% of population variability in stem volume of adult trees. This is the first study to propose UAV remote sensing as an effective tool for screening genetic variation in morphophysiological traits of adult forest trees.     

A recurrent and localized dinoflagellate bloom in a Mediterranean beach

A recurrent, prolonged and singular bloom of Alexandrium tayloriBalech in an open beach (La Fosca, Spain, NW Mediterranean)is described. Alexandrium taylori appears at several placesalong a wide area of the NW Mediterranean (Costa Brava) duringthe summer, reaching concentrations up to 10⁵ cells l^–1,but it only proliferates persistently, massively (densities>10⁶ cells l^–1) and recurrently during August in LaFosca beach. The A.taylori bloom can be considered a manifestationof large-scale proliferation in a restricted area, where couplingbetween resting cysts in the sediment and bloom outbreak isnot a major factor compared to the interaction of local environmentalconditions with the planktonic organism's life history. Fromobservations of environmental conditions (the environmentalwindow) and the multiscale spatio-temporal distributions andlife history of A.taylori, we describe the bloom dynamics andanswer some critical questions about the different phases ofthe bloom. Some of these answers are: (i) the source of theA.taylori population is widespread offshore and is not locateddirectly at the beach; (ii) high cell densities are reachedand maintained with a moderate in situ growth and low loss rates;(iii) temporary cysts act as a reserve of the population.     

Direct and indirect impacts of wildfire on faunal communities of Mediterranean temporary ponds

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