Direct seeding of Brazilian savanna trees: effects of plant cover and fertilization on seedling establishment and growth

Direct seeding is a promising technique for ecological restoration, but it has been poorly studied in neotropical savannas. Different types of plant cover (no cover, crops, or green manure) and fertilization (unfertilized, synthetic fertilizer, or poultry litter) were used to verify if survival and growth of different tree species after direct seeding could be enhanced by the use of any combination of these techniques. Seedling emergence, establishment, and growth were followed for 2 years for six savanna tree species sown in an agricultural field in Central Brazil. Germination was high (52%, on average) for Anacardium occidentale, Aspidosperma macrocarpon, Hymenaea stigonocarpa, Dipteryx alata, Eugenia dysenterica, and Magonia pubescens. Six additional species were planted, but less than 5% of these seeds germinated. Crops (60% shade) did not affect seedling survival and biomass compared with the control treatment, supporting the use of this strategy during the initial phase of restoration to involve farmers in the process. In contrast, the excessive shading (95%) from the green manure treatment decreased the survival of two species and the growth in biomass and diameter of five species, especially when combined with fertilization. Seedling growth was very slow throughout the experiment, requiring extended weed management. This study supports the use of direct seeding of the studied species for savanna restoration, but methods could be improved to include a larger number of species.     

Widespread Expression of Erythropoietin Receptor in Brain and Its Induction by Injury

Erythropoietin (EPO) exerts potent neuroprotective, neuroregenerative and procognitive functions. However, unequivocal demonstration of erythropoietin receptor (EPOR) expression in brain cells has remained difficult since previously available anti-EPOR antibodies (EPOR-AB) were unspecific. We report here a new, highly specific, polyclonal rabbit EPOR-AB directed against different epitopes in the cytoplasmic tail of human and murine EPOR and its characterization by mass spectrometric analysis of immuno-precipitated endogenous EPOR, Western blotting, immunostaining and flow cytometry. Among others, we applied genetic strategies including overexpression, Lentivirus-mediated conditional knockout of EpoR and tagged proteins, both on cultured cells and tissue sections, as well as intracortical implantation of EPOR-transduced cells to verify specificity. We show examples of EPOR expression in neurons, oligodendroglia, astrocytes and microglia. Employing this new EPOR-AB with double-labeling strategies, we demonstrate membrane expression of EPOR as well as its localization in intracellular compartments such as the Golgi apparatus. Moreover, we show injury-induced expression of EPOR. In mice, a stereotactically applied stab wound to the motor cortex leads to distinct EpoR expression by reactive GFAP-expressing cells in the lesion vicinity. In a patient suffering from epilepsy, neurons and oligodendrocytes of the hippocampus strongly express EPOR. To conclude, this new analytical tool will allow neuroscientists to pinpoint EPOR expression in cells of the nervous system and to better understand its role in healthy conditions, including brain development, as well as under pathological circumstances, such as upregulation upon distress and injury.     

Description of a new genus and three new species of Otothyrinae (Siluriformes,Loricariidae)

The genus Hisonotus was resurrected as a member of the tribe Otothyrini (actually subfamily Otothyrinae). However, phylogenetic studies based on morphological and molecular data showed that Hisonotus is not monophyletic and independent lineages can be identified, such as the group composed of the species Hisonotus insperatus, Hisonotus luteofrenatus, Hisonotus oliveirai, Hisonotus paresi and Hisonotus piracanjuba, a lineage unrelated to that containing the type species of the genus Hisonotus (Hisonotus notatus). Herein, based in molecular and morphological data, a new genus is described to accommodate the lineage mentioned above, into which are also added three new species. This new genus can be distinguished from other genera of Otothyrinae by the following combination of characters: (1) a pair of rostral plates at the tip of the snout; (2) two large pre-nasal plates just posterior to the rostral plates; (3) a supra-opercular plate that receives the laterosensory canal from the compound pterotic before the preopercle; (4) a well developed membrane at anal opening in females; and (5) a V-shaped spinelet. A key to species of Curculionichthys is provided.     

Response of wheat restricted‐tillering and vigorous growth traits to variables of climate change

The response of wheat to the variables of climate change includes elevated CO₂, high temperature, and drought which vary according to the levels of each variable and genotype. Independently, elevated CO₂, high temperature, and terminal drought affect wheat biomass and grain yield, but the interactive effects of these three variables are not well known. The aim of this study was to determine the effects of elevated CO₂ when combined with high temperature and terminal drought on the high‐yielding traits of restricted‐tillering and vigorous growth. It was hypothesized that elevated CO₂ alone, rather than combined with high temperature, ameliorates the effects of terminal drought on wheat biomass and grain yield. It was also hypothesized that wheat genotypes with more sink capacity (e.g. high‐tillering capacity and leaf area) have more grain yield under combined elevated CO₂, high temperature, and terminal drought. Two pairs of sister lines with contrasting tillering and vigorous growth were grown in poly‐tunnels in a four‐factor completely randomized split‐plot design with elevated CO₂ (700 µL L^?1), high day time temperature (3 °C above ambient), and drought (induced from anthesis) in all combinations to test whether elevated CO₂ ameliorates the effects of high temperature and terminal drought on biomass accumulation and grain yield. For biomass and grain yield, only main effects for climate change variables were significant. Elevated CO₂ significantly increased grain yield by 24–35% in all four lines and terminal drought significantly reduced grain yield by 16–17% in all four lines, while high temperature (3 °C above the ambient) had no significant effect. A trade‐off between yield components limited grain yield in lines with greater sink capacity (free‐tillering lines). This response suggests that any positive response to predicted changes in climate will not overcome the limitations imposed by the trade‐off in yield components.     

Mesoionic compounds with antifungal activity against Fusarium verticillioides

Background

Fungi contaminate the food of humans and animals, are a risk to health, and can cause financial losses. In this work, the antifungal activities of 16 mesoionic compounds (MI 1–16) were evaluated against mycotoxigenic fungi, including Aspergillus spp., Fusarium verticillioides and Penicillium citrinum. Furthermore, the decreased ergosterol in the total lipid content of Fusarium verticillioides was investigated.

Results

F. verticillioides was the most sensitive fungus to the mesoionic compounds. Among the evaluated compounds, MI-11 and MI-16 presented higher antifungal effects against F. verticillioides, with MIC values of 7.8 μg/ml, and MI-2 and MI-3 followed, with MICs of 15.6 μg/ml. The most active compounds were those with heterocyclic ring phenyl groups substituted by electron donor moieties (MI-11 and MI-16). Among some compounds with higher activity (MI-2, MI-11 and MI-16), decreased ergosterol content in the total lipid fraction of F. verticillioides was demonstrated. MI-2 reduced the ergosterol content approximately 40% and 80% at concentrations of 7.8 μg/ml and 15.6 μg/ml, respectively, and MI-11 and MI-16 decreased the content by 30% and 50%, respectively, when at a concentration of 7.8 μg/ml.

Conclusion

These findings indicate that mesoionic compounds have significant antifungal activity against F. verticillioides.     

Multiple O-glucosylation sites on Notch function as a buffer against temperature-dependent loss of signaling

Mutations in Drosophila rumi result in a temperature-sensitive loss of Notch signaling. Rumi is a protein O-glucosyltransferase that adds glucose to EGF repeats with a C-X-S-X-P-C consensus sequence. Eighteen of the 36 EGF repeats in the Drosophila Notch receptor contain the consensus O-glucosylation motif. However, the contribution of individual O-glucose residues on Notch to the regulation of Notch signaling is not known. To address this issue, we carried out a mutational analysis of these glucosylation sites and determined their effects on Notch activity in vivo. Our results indicate that even though no single O-glucose mutation causes a significant decrease in Notch activity, all of the glucose residues on Notch contribute in additive and/or redundant fashions to maintain robust signaling, especially at higher temperatures. O-glucose motifs in and around the ligand-binding EGF repeats play a more important role than those in other EGF repeats of Notch. However, a single O-glucose mutation in EGF12 can be compensated by other O-glucose residues in neighboring EGF repeats. Moreover, timecourse cell aggregation experiments using a rumi null cell line indicate that a complete lack of Rumi does not affect Notch-Delta binding at high temperature. In addition, rumi fully suppresses the gain-of-function phenotype of a ligand-independent mutant form of Notch. Our data suggest that, at physiological levels of Notch, the combined effects of multiple O-glucose residues on this receptor allow productive S2 cleavage at high temperatures and thereby serve as a buffer against temperature-dependent loss of Notch signaling.