Genomic Evolution of Two Acinetobacter baumannii Clinical Strains from ST-2 Clones Isolated in 2000 and 2010 (ST-2_clon_2000 and ST-2_clon_2010)

Acinetobacter baumannii is a successful nosocomial pathogen due to its ability to persist in hospital environments by acquiring mobile elements such as transposons, plasmids, and phages. In this study, we compared two genomes of A. baumannii clinical strains isolated in 2000 (ST-2_clon_2000) and 2010 (ST-2_clon_2010) from GenBank project PRJNA308422

Glacial Isostatic Adjustment of the Laurentian Great Lakes Basin: Using the Empirical Record of Strandline Deformation for Reconstruction of Early Holocene Paleo-Lakes and Discovery of a Hydrologically Closed Phase

In the Great Lakes region, the vertical motion of crustal rebound since the last glaciation has decelerated with time, and is described by exponential decay constrained by observed warping of strandlines of former lakes. A composite isostatic response surface relative to an area southwest of Lake Michigan beyond the limit of the last glacial maximum was prepared for the complete Great Lakes watershed at 10.6 ka BP (12.6 cal ka BP). Uplift of sites computed using values from the response surface facilitated the transformation of a digital elevation model of the present Great Lakes basins to represent the paleogeography of the watershed at selected times. Similarly, the original elevations of radiocarbon-dated geomorphic and stratigraphic indicators of former lake levels were reconstructed and plotted against age to define lake level history. A comparison with the independently computed basin outlet paleo-elevations reveals a phase of severely reduced water levels and hydrologically-closed lakes below overflow outlets between 7.9 and 7.0 ka BP (8.7 and 7.8 cal ka BP) in the Huron-Michigan basin. Severe evaporative draw-down is postulated to result from the early Holocene dry climate when inflows of meltwater from the upstream Agassiz basin began to bypass the upper Great Lakes basin.Dans la région des Grands Lacs, le soulèvement isostatique lié à la dernière glaciation a ralenti selon une courbe de décroissance exponentielle établie à partir du gauchissement observé dans les anciennes lignes de rivage lacustres. Une surface de référence composite de la réponse isostatique datant de 10,6 ka BP (12,6 cal ka BP) a été préparée pour l’ensemble du bassin-versant des Grands Lacs, par rapport à une région au sud-ouest du lac Michigan située au-delà de la limite du dernier maximum glaciaire. Le calcul du soulèvement des sites en fonction des altitudes de la surface de référence a facilité la conversion d’un modèle altimétrique de terrain du bassin actuel des Grands Lacs en des cartes paléo-géographiques pour différents âges choisis. De plus, afin de définir l’évolution des niveaux lacustres, les altitudes initiales des indicateurs géomorphologiques et stratigraphiques des paléo-niveaux lacustres, datés au 14C, ont été reconstituées puis reportées en fonction de l’âge. La comparaison de cette courbe à celles des paléo-altitudes des exutoires lacustres, calculée indépendamment, révèle, entre 7,9 et 7 ka BP (8,7 et 7,8 cal ka BP), une phase d’abaissement majeur des niveaux lacustres au-dessous de ceux des exutoires et la fermeture hydrologique des lacs dans le bassin des lacs Huron-Michigan. La forte évaporation nécessaire à l’abaissement du niveau d’eau est attribuée à un climat sec peu après le début de l’Holocène, dans un contexte de détournement progressif hors des Grands Lacs des eaux de fonte du lac Agassiz

Some functional relations derived from the Lindelöf-Wirtinger expansion of the Lerch transcendent function

The Lindelöf-Wirtinger expansion of the Lerch transcendent function implies, as a limiting case, Hurwitz’s formula for the eponymous zeta function. A generalized form of M ¨obius inversion applies to the Lindelöf-Wirtinger expansion and also implies an inversion formula for the Hurwitz zeta function as a limiting case. The inverted formulas involve the dynamical system of rotations of the circle and yield an arithmetical functional equation

Correlated response in early embryonic development in rabbits selected for litter size variability

[EN] A divergent selection experiment for litter size variability was carried out in rabbits. The litter size variability was estimated as the phenotypic variance of litter size within female. The aim of this study was to assess the effect of selecting for litter size variability on early embryonic development and survival after 7 generations of divergent selection (high and low variability lines). A total of 30 non-lactating multiparous does per line were used. The ovulation rate and early embryonic development were analysed using Bayesian methodology. Ovulation rate was not affected by the selection process. At 28 h of gestation, embryonic development and survival were similar in both lines. At 48 h of gestation, the majority of embryos in the high line were in the early morulae stage. The high line had a higher proportion of early morulae (79.54 vs. 53.43%; P=0.94) and a lower proportion of compacted morulae (20.46 vs. 46.57%; P=0.93%) than the low line. At 72 h of gestation, the high line had 1.59 fewer embryos than the more homogeneous line (P=0.85), due to reduced embryonic survival (0.60 vs. 0.74; P=0.93). The high line continued to show a higher proportion of early morulae (21.01 vs. 3.69%; P=0.93) and a lower proportion of compacted morulae and blastocysts (78.99 vs. 96.31%; P=0.94) than the low line at 72 h of gestation, indicative of reduced embryonic development. In conclusion, selection for homogeneity in litter size had a positive impact on embryonic traits.This study was financed by the Spanish Ministry of Economy and Competitiveness (MINECO) (Grant no. AGL2011-29831-C03-02 and AGL2014-55921-C2-2-P). Eddy W. Calle was supported by a research grant within the Babel project from the Erasmus Mundus programme.Calle, EW.; García, ML.; Blasco, A.; Argente, M. (2017). Correlated response in early embryonic development in rabbits selected for litter size variability. World Rabbit Science. 25(4):323-327. https://doi.org/10.4995/wrs.2017.6340SWORD32332725

Correlated response in litter size components in rabbits selected for litter size variability

[EN] A divergent selection experiment for the environmental variability of litter size (Ve) over seven generations was carried out in rabbits at the University Miguel Hernandez of Elche. The Ve was estimated as the phenotypic variance within the female, after correcting for year-season and parity-lactation status. The aim of this study was to analyse the correlated responses to selection in litter size components. The ovulation rate (OR) and number of implanted embryos (IE) in females were measured by laparoscopy at 12 day of the second gestation. At the end of the second gestation, the total number of kits born was measured (TB). Embryonic (ES), foetal (FS) and prenatal (PS) survival were computed as IE/OR, TB/IE and TB/OR, respectively. A total of 405 laparoscopies were performed. Data were analysed using Bayesian methodology. The correlated response to selection for litter size environmental variability in terms of the litter size components was estimated as either genetic trends, estimated by computing the average estimated breeding values for each generation and each line, or the phenotypic differences between lines. The OR was similar in both lines. However, after seven generations of selection, the homogenous line showed more IE (1.09 embryos for genetic means and 1.23 embryos for phenotypic means) and higher ES than the heterogeneous one (0.07 for genetic means and 0.08 for phenotypic means). The probability of the phenotypic differences between lines being higher than zero (p) was 1.00 and .99, respectively. A higher uterine overcrowding of embryos in the homogeneous line did not penalize FS; as a result, this line continued to show a greater TB (1.01 kits for genetic means and 1.30 kits for phenotypic means, p=.99, in the seventh generation). In conclusion, a decrease in litter size variability showed a favourable effect on ES and led to a higher litter size at birth.Spanish Ministry of Economy and Competitiveness (MINECO), Grant/Award Number: AGL2011-29831-C03-02, AGL2014-55921-C2-2-P; Babel project from the Erasmus Mundus programmeArgente, MJ.; Calle, EW.; Garcia, ML.; Blasco Mateu, A. (2017). Correlated response in litter size components in rabbits selected for litter size variability. Journal of Animal Breeding and Genetics. 134(6):505-511. https://doi.org/10.1111/jbg.12283S505511134

Analysis of Complete Genome Sequence of <i>Acinetobacter</i> <i>baumannii</i> Strain ATCC 19606 Reveals Novel Mobile Genetic Elements and Novel Prophage.

Acinetobacter baumannii isolate ATCC 19606 was recovered in the US prior to 1948. It has been used as a reference and model organism in many studies involving antibiotic resistance and pathogenesis of A. baumannii, while, until recently, a complete genome of this strain was not available. Here, we present an analysis of the complete 3.91-Mbp genome sequence, generated via a combination of short-read sequencing (Illumina) and long-read sequencing (MinION), and show it contains two small cryptic plasmids and a novel complete prophage of size 41.2 kb. We also characterised several regions of the ATCC 19606 genome, leading to the identification of a novel cadmium/mercury transposon, which was named Tn6551. ATCC 19606 is an antibiotic-sensitive strain, but a comparative analysis of all publicly available ST52 strains predicts a resistance to modern antibiotics by the accumulation of antibiotic-resistance genes via plasmids in recent isolates that belong to this sequence type

In vivo immunomodulatory and antioxidant properties of nanoceria (nCeO2) in the marine mussel Mytilus galloprovincialis

Cerium nanoparticles (nCeO2) are increasingly utilized in a wide variety of industrial, environmental and biomedical applications, and are therefore expected to be released in the aquatic environment. Due to its peculiar redox properties, nCeO2 may present unique hazards to environmental and human health. Previous data showed that in the hemocytes of the marine bivalve Mytilus galloprovincialis, in vitro exposure to a particular type of nCeO2 (9 nm, characterized by negative ζ-potential, high H2O2 scavenging capacity and Ce3+/Ce4+ surface ratio) reduced basal ROS production, lysosomal membrane stability and phagocytic activity in the presence of hemolymph serum; the effects observed were partly ascribed to the formation of a SOD-protein corona in the hemolymph. In this work, the in vivo effects of this type of nCeO2 were investigated in mussels exposed to 100 μg/L nCeO2 for 96 h; several lysosomal, immune, inflammatory and antioxidant biomarkers were measured at cellular (hemocytes) and tissue (gills, digestive gland) level. Molecular responses were evaluated in hemocytes and digestive gland by determining expression of 11 selected genes related to known biological functions. The results show specific immunomodulatory and antioxidant effects of nCeO2 at different levels of biological organization in the absence of Cerium tissue accumulation. These data further support the redox mechanisms at the basis of the physiological effects of nCeO2. Finally, in order to evaluate the possible impact at the whole organism level, the effects of nCeO2 were evaluated in the 48 h embryotoxicity assay in a wide concentration range. However, nCeO2 exposure resulted in a small reduction in normal embryo development. Overall, the results demonstrate that in mussels nCeO2 can selectively modulate different physiological processes at different levels of biological organization

A simple computation of Z(2k)

We present a new simple proof of Euler’s formulas for Z(2k), where k= 1,2,3,.... The computation is done using only the defining properties of the Bernoulli polynomials and summing a telescoping series, and the same method also yields integral formulas for Z(2k+ 1)

Combined use of the Ab105-2фΔCI lytic mutant phage and different antibiotics in clinical isolates of multiresistant Acinetobacter baumannii

Phage therapy is an abandoned antimicrobial therapy that has been resumed in recent years. In this study, we mutated a lysogenic phage from Acinetobacter baumannii into a lytic phage (Ab105-2phiΔCI) showing antimicrobial activity against A.baumannii clinical strains(such as Ab177_GEIH-2000 which showed MICs to meropenem and imipenem of 32 μg/ml and 16 μg/ml, respectively as well as belonging to GEIH-REIPI Spanish MulticenterA. baumannii Study II 2000/2010, Umbrella Genbank Bioproject PRJNA422585).We observed in vitro, an antimicrobial synergistic effect(from 4 log to 7 log CFU/ml) with meropenem plus lytic phage in all combinations analysed(0.1, 1 and 10 MOI of Ab105-2phiΔCI mutant as well as 1/4 and 1/8 MIC of meropenem). Moreover, we had a decrease in bacterial growth of 8 log CFU/ml for the combination of imipenem at 1/4 MIC plus lytic phage(Ab105-2phiΔCI mutant) and of 4 log CFU/ml for the combination of imipenem at 1/8 MIC plus lytic phage (Ab105-2phiΔCI mutant) in both MOI 1 and 10.These results were confirmed in in vivo(G. mellonella) obtaining a higher effectiveness in thecombination of imipenem and Ab105-2phiΔCI mutant(P<0.05). This approach could help to reducethe emergence of phage resistant bacteria and restore sensitivity to the antibiotics when used tocombat multiresistant strains of Acinetobacter baumannii