Reproductive ecology of Brazilian freshwater fishes

We used metadata on nine reproductive traits of 67 species of Brazilian iteroparous, oviparous, teleost freshwater fishes to test phenotypes associations to discriminate species that only spawn in large rivers (lotic fishes) from those capable to spawn in lentic habitats (lentic fishes). We tested the hypothesis that lotic fishes present spawning migration, shorter spawning season, single spawning, no parental care, free eggs, higher relative fecundity, faster embryogenesis, and larger size, while lentic fishes present no spawning migration, longer spawning season, multiple spawning, parental care, adhesive eggs, lower relative fecundity, slower embryogenesis, and smaller size. Our analyses supported the hypothesis but not all phenotypic associations satisfied it, specifically with regard to lentic fishes or to pairs of phenotypes typical of lentic fishes. We also concluded that spawning in large rivers is a better predictor of bionomic characters than spawning in lentic habitats, and lotic fishes are specialists compared to lentic fishes.     

Identification of a Site in Sar1 Involved in the Interaction with the Cytoplasmic Tail of Glycolipid Glycosyltransferases

Glycolipid glycosyltransferases (GGT) are transported from the endoplasmic reticulum (ER) to the Golgi, their site of residence, via COPII vesicles. An interaction of a (R/K)X(R/K) motif at their cytoplasmic tail (CT) with Sar1 is critical for the selective concentration in the transport vesicles. In this work using computational docking, we identify three putative binding pockets in Sar1 (sites A, B, and C) involved in the interaction with the (R/K)X(R/K) motif. Sar1 mutants with alanine replacement of amino acids in site A were tested in vitro and in cells. In vitro, mutant versions showed a reduced ability to bind immobilized peptides with the CT sequence of GalT2. In cells, Sar1 mutants (Sar1^D198A) specifically affect the exiting of GGT from the ER, resulting in an ER/Golgi concentration ratio favoring the ER. Neither the typical Golgi localization of GM130 nor the exiting and transport of the G protein of the vesicular stomatitis virus were affected. The protein kinase inhibitor H89 produced accumulation of Sec23, Sar1, and GalT2 at the ER exit sites; Sar1^D189A also accumulated at these sites, but in this case GalT2 remained disperse along ER membranes. The results indicate that amino acids in site A of Sar1 are involved in the interaction with the CT of GGT for concentration at ER exiting sites.     

High survival rate of a critically endangered species, the Azores Bullfinch Pyrrhula murina, as a contribution to population recovery

This paper reports analyses of a capture–mark–recapture (CMR) dataset of 149 Azores Bullfinches ringed on S?o Miguel island (Azores) between 2005 and 2007, and recaptured–resighted on a monthly basis over a 4-year period (2005–2008) throughout their breeding range. We examined the effect of time, age (adults vs. juveniles), gender (adult males and females), and environmental covariates (temperature, rainfall, NAO index) on survival probabilities. The modelling found a high and constant monthly survival probability (mean ± SE) estimated at 0.96 ± 0.01, similar between both adults and juveniles and independent of environmental conditions and gender. These findings agree with expectations from island-based life-history theory where relatively mild conditions and lack of predators should favour high survival rates to compensate for the low reproductive output. The annual survival rate was estimated at 0.62, which was also consistent with this pattern when compared with survival estimates of mainland bullfinch and passerine species on other subtropical islands obtained in similar CMR studies. Based on a canonical estimator, the size of the studied population (mean ± SE) was estimated at 1608 ± 326 individuals. Given that the population size was only around 120–400 individuals in the early 1990s, we suggest that the high survival probabilities currently applying to this critically endangered species may have substantially contributed to the recent recovery of this population. Future research studies on the species’ demography should continue to monitor survival in order to measure the effect of management interventions currently taking place within the range of the Azores Bullfinch, including the restoration of the biodiversity rich laurel forest, but also focusing on nest success, which is important for understanding population dynamics.     

Nannoplankton biostratigraphic calibration of the evaporitic events in the Neogene Fortuna Basin (SE Spain)

The Fortuna Basin is an example of a marginal Mediterranean basin with evaporitic sedimentation during the Late Tortonian and Messinian. This basin shows an early restriction event before the main Messinian Salinity Crisis (MSC) that allows the Tortonian Salinity Crisis (TSC) to be proposed as a tectonic uplift event isolating the eastern Betic basins. Four evaporitic events are present in the central part of the Fortuna Basin, from bottom to top: Los Baños Marls Formation (composed by Fenazar Conglomerate Bed, Lower Gypsum Member [Mb] and Sanel Mb), Tale Gypsum Formation (Fm), Chicamo Diatomites and Gypsum Cycles Fm, and Rambla Salada Gypsum Fm. The present work documents the first biostratigraphic dating based on calcareous nannoplankton of these events. The lowest occurrence (LO) of Amaurolithus primus is registered at the upper part of the Sanel Mb, below the Tale Gypsum Fm. The LOs of Amaurolithus delicatus and Reticulofenestra rotaria, which mark the base of the Messinian, occur in the lower part of the Chicamo Cycles Fm, above the Tale Gypsum Fm, the Triquetrorhabdulus rugosus-Nicklithus amplificus integrate form and the LO of Nicklithus cf. amplificus in the upper part of the Chicamo Cycles Fm. Taking into account these results, a new calibration of the available magnetostratigraphic data is presented: the Chicamo Cycles Fm were formed during the reverse chron C3Ar and the Tortonian-Messinian boundary should be found within the Tale Gypsum Fm or near the top of the Sanel Mb. The onset of the TSC, the first restriction phase of the Fortuna Basin, is represented by the Fenazar Conglomerate Bed, bottom of the Los Baños Fm, and not by the Tale Gypsum Fm, as previously considered.     

Spatial Variation in the Strength of a Trophic Cascade Involving Ruellia nudiflora (Acanthaceae), an Insect Seed Predator and Associated Parasitoid Fauna in Mexico

Spatial variation in the strength of herbivore top-down control represents an important source of variation in plant fitness measures and community structure and function. By measuring seed predator (larvae of a Noctuid moth) and parasitoid impacts on Ruellia nudiflora across a broad spatial scale in Yucatan (Mexico), this study addressed the following: (1) to what extent does seed predator and parasitoid attack intensity associated with R. nudiflora vary spatially? (2) Does parasitoid attack result in a positive indirect effect on the plant, and does the intensity of this effect vary spatially? During the peak of fruit production (late June–early July) of 2005, we collected fruits from 21 R. nudiflora populations and grouped them into four regions: center, east, north and south. For each fruit we recorded: observed seed number, number of seeds eaten, seed predator presence, parasitoid presence and number of seeds ‘saved’ by parasitoids. Seed predators attacked ca 30 percent of fruits/plant on average, while parasitoids were found in 24 percent of seed predator-attacked fruits. Results indicated spatial variation in seed predator and parasitoid attack levels; interestingly, a contrasting spatial gradient of attack intensity was observed: populations/regions with greatest parasitoid attack levels usually had the lowest seed predator attack levels and vice versa, suggesting top-down control of parasitoids on seed predators. We observed a weak overall indirect impact of parasitoids on R. nudiflora (4% seeds ‘saved’ on average), which nonetheless varied strongly across populations (e.g., close to 14% seeds saved at one population). Findings indicate a geographical structuring of interaction strengths across populations, as well as spatial variation in the strength of parasitoid cascading effects on plant reproduction.     

Synthesis of seleno-carbohydrates derived from d-galactose

The synthesis of seleno-galactopyranosides in a short and efficient manner is described, starting from the parent carbohydrate d-galactose. The approach described allows the synthesis of small libraries of compounds with a number of structural variations at the group attached to selenium. Compounds with aryl, propargyl, allyl, acyl, and alkyl substituents are described.     

Regulation of mTOR Complex 1 (mTORC1) by Raptor Ser863 and Multisite Phosphorylation

The rapamycin-sensitive mTOR complex 1 (mTORC1) promotes protein synthesis, cell growth, and cell proliferation in response to growth factors and nutritional cues. To elucidate the poorly defined mechanisms underlying mTORC1 regulation, we have studied the phosphorylation of raptor, an mTOR-interacting partner. We have identified six raptor phosphorylation sites that lie in two centrally localized clusters (cluster 1, Ser⁶⁹⁶/Thr⁷⁰⁶ and cluster 2, Ser⁸⁵⁵/Ser⁸⁵⁹/Ser⁸⁶³/Ser⁸⁷⁷) using tandem mass spectrometry and generated phosphospecific antibodies for each of these sites. Here we focus primarily although not exclusively on raptor Ser⁸⁶³ phosphorylation. We report that insulin promotes mTORC1-associated phosphorylation of raptor Ser⁸⁶³ via the canonical PI3K/TSC/Rheb pathway in a rapamycin-sensitive manner. mTORC1 activation by other stimuli (e.g. amino acids, epidermal growth factor/MAPK signaling, and cellular energy) also promote raptor Ser⁸⁶³ phosphorylation. Rheb overexpression increases phosphorylation on raptor Ser⁸⁶³ as well as on the five other identified sites (e.g. Ser⁸⁵⁹, Ser⁸⁵⁵, Ser⁸⁷⁷, Ser⁶⁹⁶, and Thr⁷⁰⁶). Strikingly, raptor Ser⁸⁶³ phosphorylation is absolutely required for raptor Ser⁸⁵⁹ and Ser⁸⁵⁵ phosphorylation. These data suggest that mTORC1 activation leads to raptor multisite phosphorylation and that raptor Ser⁸⁶³ phosphorylation functions as a master biochemical switch that modulates hierarchical raptor phosphorylation (e.g. on Ser⁸⁵⁹ and Ser⁸⁵⁵). Importantly, mTORC1 containing phosphorylation site-defective raptor exhibits reduced in vitro kinase activity toward the substrate 4EBP1, with a multisite raptor 6A mutant more strongly defective that single-site raptor S863A. Taken together, these data suggest that complex raptor phosphorylation functions as a biochemical rheostat that modulates mTORC1 signaling in accordance with environmental cues.     

Importancia de la determinación de variantes en el número de copias en neonatos con aneuploidías autosómicas

Introduction:

Aneuploidies are frequent genetic disorders in clinical practice. However, little is known about other genetic variants that may influence the final phenotype.

Objective:

To determine the variations in the number of copies and regions with homozygosity greater than 0.5% or larger than 10 Mb in newborns with autosomal aneuploidies.

Materials and methods:

We performed a chromosomal microarray analysis on newborns with autosomal aneuploidies (n=7), trisomy 21 (n=5), and trisomy 18 (n=2) evaluated at the Hospital Antonio Lorena and Hospital Regional of Cusco, Perú, during 2018.

Results:

We found pathogenic and probably pathogenic variants in the number of copies in other genomic regions different to chromosomes 21 or 18 in two neonates. Additionally, we found two variants bigger than 500 kpb of unknown pathogenicity.

Conclusions:

Although the number of analyzed individuals was small, it is important to highlight that we found other variants in the number of copies that have been described in association with neurodevelopmental disorders, congenital anomalies, deafness, and short/ tall stature, among others, in almost half of them, which will probably impact the phenotype negatively in patients with aneuploidies.     

Assessment of oxidative damage induced by acute doses of morphine sulfate in postnatal and adult rat brain

The aim of the present study is to evaluate the oxidative damage in rats of different ages. Weaned rats of 25 g and adults of 300 g were used in groups of 6, a single i.p. dose of morphine sulfate of 3, 6 or 12 mg/kg was administered. All animals were sacrificed to measure GSH and 5-HT levels in brain by liquid chromatography, as well as Na⁺, K⁺-ATPase and total ATPase enzymatic activity. 5-HT levels decreased significantly (p<0.05) in adult animals that received 3 and 6 mg morphine. Na⁺, K⁺-ATPase activity increased significantly (p<0.05) in all groups of weaned animals. In adult animals, Na⁺, K⁺-ATPase and total ATPase partially diminished. GSH levels diminished significantly (p<0.05) both in weaned and in adult groups. The results indicate age-induced changes in cellular regulation and biochemical responses to oxidative stress induced by morphine.     

Inferring parameters shaping amino acid usage in prokaryotic genomes via Bayesian MCMC methods

Molar content of guanine plus cytosine (G + C) and optimal growth temperature (OGT) are main factors characterizing the frequency distribution of amino acids in prokaryotes. Previous work, using multivariate exploratory methods, has emphasized ascertainment of biological factors underlying variability between genomes, but the strength of each identified factor on amino acid content has not been quantified. We combine the flexibility of the phylogenetic mixed model (PMM) with the power of Bayesian inference via Markov Chain Monte Carlo (MCMC) methods, to obtain a novel evolutionary picture of amino acid usage in prokaryotic genomes. We implement a Bayesian PMM which incorporates the feature that evolutionary history makes observed data interdependent. As in previous studies with PMM, we present a variance partition; however, attention is also given to the posterior distribution of "systematic effects" that may shed light about the relative importance of and relationships between evolutionary forces acting at the genomic level. In particular, we analyzed influences of G + C, OGT, and respiratory metabolism. Estimates of G + C effects were significant for amino acids coded by G + C or molar content of adenine plus thymine (A + T) in first and second bases. OGT had an important effect on 12 amino acids, probably reflecting complex patterns of protein modifications, to cope with varying environments. The effect of respiratory metabolism was less clear, probably due to the already reported association of G + C with aerobic metabolism. A "heritability" parameter was always high and significant, reinforcing the importance of accommodating phylogenetic relationships in these analyses. "Heritable" component correlations displayed a pattern that tended to cluster "pure" G + C (A + T) in first and second codon positions, suggesting an inherited departure from linear regression on G + C.