A Major Locus Controls a Genital Shape Difference Involved in Reproductive Isolation Between Drosophila yakuba and Drosophila santomea

International audienceRapid evolution of genitalia shape, a widespread phenomenon in animals with internal fertilization, offers the opportunity to dissect the genetic architecture of morphological evolution linked to sexual selection and speciation. Most quantitative trait loci (QTL) mapping studies of genitalia divergence have focused on Drosophila melanogaster and its three most closely related species, D. simulans, D. mauritiana, and D. sechellia, and have suggested that the genetic basis of genitalia evolution involves many loci. We report the first genetic study of male genitalia evolution between D. yakuba and D. santomea, two species of the D. melanogaster species subgroup. We focus on male ventral branches, which harm females during interspecific copulation. Using landmark-based geometric morphometrics, we characterized shape variation in parental species, F1 hybrids, and backcross progeny and show that the main axis of shape variation within the backcross population matches the interspecific variation between parental species. For genotyping, we developed a new molecular method to perform multiplexed shotgun genotyping (MSG), which allowed us to prepare genomic DNA libraries from 365 backcross individuals in a few days using little DNA. We detected only three QTL, one of which spans 2.7 Mb and exhibits a highly significant effect on shape variation that can be linked to the harmfulness of the ventral branches. We conclude that the genetic architecture of genitalia morphology divergence may not always be as complex as suggested by previous studies

Purification and properties of the very high density lipoprotein from the hemolymph of adult Triatoma infestans

The very high density lipoprotein (VHDL) of Triatoma injesfum hemolymph from adult males has been isolated and purified by two-step density gradient ultracentrifugation. It appears to be homogeneous as judged by native polyacrylamide gel electrophoresis. The content of VHDL in hemolymph was estimated to be 8 mg proteidml. The purified protein has a molecular weight (M,) of 450,000, is composed of six subunits of M, p 77,000, and possesses a high content of aromatic amino acids. This protein is glycosylated and contains 3% of lipids by weight with a remarkable amount of free fatty acids (25% of total lipids). The I: injesfans VHDL has a different lipid and amino acid composition from lipophorin. The lipid composition and the spectroscopic studies using cis-parinaric acid indicated a high fatty acid binding affinity. It has nine binding sites per mol of VHDL. Competence studies revealed that VHDL has its highest affinity for the binding of palmitic acid followed by stearic and arachidonic acids.Instituto de Investigaciones Bioquímicas de La Plat

Estudio Comparativo de Métodos de Selección de Características de Inferencia Supervisada y No Supervisada

In this work, a comparative study of feature selection methods for supervised and unsupervised inference obtained from classical PCA is presented. We deduce an expression for the cost function of PCA based on the mean square error of data and its orthonormal projection, and then this concept is extended to obtain an expression for general WPCA. Additionally, we study the supervised and unsupervised Q – α algorithm and its relation with PCA. At the end, we present results employing two data sets: A low-dimensional data set to analyze the effects of orthonormal rotation, and a highdimensional data set to assess the classification performance. The feature selection methods were assessed taking into account the number of relevant features, computational cost and classification performance. The classification was carried out using a partitional clustering algorithm.En este trabajo se presenta un estudio comparativo de algunos métodos de selección de características de inferencia supervisada y no supervisada derivados del algoritmo PCA clásico. Se deduce una función objetivo de PCA a partir del error cuadrático medio de los datos y su proyección sobre una base ortonormal, y se extiende este concepto para derivar una expresión asociada al algoritmo fundamental de WPCA. Adicionalmente, se estudian los algoritmos Q - α supervisado y no supervisado y se explica su relación con PCA. Se presentan resultados empleando dos conjuntos de datos: Uno de baja dimensión para estudiar los efectos de la rotación ortogonal y la dirección de los componentes principales y otro de alta dimensión para evaluar los resultados de clasificación. Los métodos de selección de características fueron evaluados teniendo en cuenta la cantidad de características relevantes obtenidas, costo computacional y resultados de clasificación. La clasificación se realizó con un algoritmo particional de agrupamiento no supervisado

Estudio Comparativo de Métodos de Selección de Características de Inferencia Supervisada y No Supervisada

In this work, a comparative study of feature selection methods for supervised and unsupervised inference obtained from classical PCA is presented. We deduce an expression for the cost function of PCA based on the mean square error of data and its orthonormal projection, and then this concept is extended to obtain an expression for general WPCA. Additionally, we study the supervised and unsupervised Q – α algorithm and its relation with PCA. At the end, we present results employing two data sets: A low-dimensional data set to analyze the effects of orthonormal rotation, and a highdimensional data set to assess the classification performance. The feature selection methods were assessed taking into account the number of relevant features, computational cost and classification performance. The classification was carried out using a partitional clustering algorithm.En este trabajo se presenta un estudio comparativo de algunos métodos de selección de características de inferencia supervisada y no supervisada derivados del algoritmo PCA clásico. Se deduce una función objetivo de PCA a partir del error cuadrático medio de los datos y su proyección sobre una base ortonormal, y se extiende este concepto para derivar una expresión asociada al algoritmo fundamental de WPCA. Adicionalmente, se estudian los algoritmos Q - α supervisado y no supervisado y se explica su relación con PCA. Se presentan resultados empleando dos conjuntos de datos: Uno de baja dimensión para estudiar los efectos de la rotación ortogonal y la dirección de los componentes principales y otro de alta dimensión para evaluar los resultados de clasificación. Los métodos de selección de características fueron evaluados teniendo en cuenta la cantidad de características relevantes obtenidas, costo computacional y resultados de clasificación. La clasificación se realizó con un algoritmo particional de agrupamiento no supervisado

Cytological characterization of sunflower by in situ hybridization using homologous rDNA sequences and a BAC clone containing highly represented repetitive retrotransposon-like sequences

In the present work we report new tools for the characterization of the complete chromosome complement of sunflower (Helianthus annuus L.), using a bacterial artificial chromosome (BAC) clone containing repetitive sequences with similarity to retrotransposons and a homologous rDNA sequence isolated from the sunflower genome as probes for FISH. The rDNA signal was found in 3 pairs of chromosomes, coinciding with the location of satellites. The BAC clone containing highly represented retroelements hybridized with all the chromosome complement in FISH, and used together with the rDNA probe allowed the discrimination of all chromosome pairs of sunflower. Their distinctive distribution pat-tern suggests that these probes could be useful for karyotype characterization and for chromosome identification. The karyotype could be subdivided into 3 clear-cut groups of 12 metacentric pairs, 1 submetacentric pair, and 4 subtelocentric pairs, thus resolving previously described karyotype controversies. The use of BAC clones containing single sequences of specific markers and (or) genes associated with important agricultural traits represents an important tool for future locus-specific identification and physical mapping.Fil: Talia, Paola Monica. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Greizerstein, Eduardo Jose. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Díaz Quijano, C.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Peluffo, Lucila. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fernández, L.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Fernández, P.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Hopp, Horacio Esteban. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Paniego, Norma Beatriz. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Heinz, Ruth Amelia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Poggio, Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentin

Purification and properties of the very high density lipoprotein from the hemolymph of adult Triatoma infestans

The very high density lipoprotein (VHDL) of Triatoma injesfum hemolymph from adult males has been isolated and purified by two-step density gradient ultracentrifugation. It appears to be homogeneous as judged by native polyacrylamide gel electrophoresis. The content of VHDL in hemolymph was estimated to be 8 mg proteidml. The purified protein has a molecular weight (M,) of 450,000, is composed of six subunits of M, p 77,000, and possesses a high content of aromatic amino acids. This protein is glycosylated and contains 3% of lipids by weight with a remarkable amount of free fatty acids (25% of total lipids). The I: injesfans VHDL has a different lipid and amino acid composition from lipophorin. The lipid composition and the spectroscopic studies using cis-parinaric acid indicated a high fatty acid binding affinity. It has nine binding sites per mol of VHDL. Competence studies revealed that VHDL has its highest affinity for the binding of palmitic acid followed by stearic and arachidonic acids.Instituto de Investigaciones Bioquímicas de La Plat

Interaction between epidermal growth factor receptor and C-C motif chemokine receptor 2 in the ovulatory cascade

The epidermal growth factor receptor (EGFR) signaling pathway is one of the main pathways responsible for propagating the luteinizing hormone (LH) signal throughout the cumulus cells and the oocyte. Recently, we have proposed the C-C motif chemokine receptor 2 (CCR2) and its main ligand (monocyte chemoattractant protein-1, MCP1) as novel mediators of the ovulatory cascade. Our previous results demonstrate that the gonadotropins (GNT), amphiregulin (AREG), and prostaglandin E2 (PGE2) stimulation of periovulatory gene mRNA levels occurs, at least in part, through the CCR2/MCP1 pathway, proposing the CCR2 receptor as a novel mediator of the ovulatory cascade in a feline model. For that purpose, feline cumulus-oocyte complexes (COCs) were cultured in the presence or absence of an EGFR inhibitor, recombinant chemokine MCP1, and gonadotropins [as an inducer of cumulus-oocyte expansion (C-OE), and oocyte maturation] to further assess the mRNA expression of periovulatory key genes, C-OE, oocyte nuclear maturation, and steroid hormone production. We observed that MCP1 was able to revert the inhibition of AREG mRNA expression by an EGFR inhibitor within the feline COC. In accordance, the confocal analysis showed that the GNT-stimulated hyaluronic acid (HA) synthesis, blocked by the EGFR inhibitor, was recovered by the addition of recombinant MCP1 in the C-OE culture media. Also, MCP1 was able to revert the inhibition of progesterone (P4) production by EGFR inhibitor in the C-OE culture media. Regarding oocyte nuclear maturation, recombinant MCP1 could also revert the inhibition triggered by the EGFR inhibitor, leading to a recovery in the percentage of metaphase II (MII)-stage oocytes. In conclusion, our results confirm the chemokine receptor CCR2 as a novel intermediate in the ovulatory cascade and demonstrate that the EGFR/AREG and the CCR2/MCP1 signaling pathways play critical roles in regulating feline C-OE and oocyte nuclear maturation, with CCR2/MCP1 signaling pathway being downstream EGFR/AREG pathway within the ovulatory cascade

AMP-activated protein kinase deficiency reduces ozone-induced lung injury and oxidative stress in mice

<p>Abstract</p> <p>Background</p> <p>Acute ozone exposure causes lung oxidative stress and inflammation leading to lung injury. At least one mechanism underlying the lung toxicity of ozone involves excessive production of reactive oxygen and nitrogen intermediates such as peroxynitrite. In addition and beyond its major prooxidant properties, peroxynitrite may nitrate tyrosine residues altering phosphorylation of many protein kinases involved in cell signalling. It was recently proposed that peroxynitrite activates 5'-AMP-activated kinase (AMPK), which regulates metabolic pathways and the response to cell stress. AMPK activation as a consequence of ozone exposure has not been previously evaluated. First, we tested whether acute ozone exposure in mice would impair alveolar fluid clearance, increase lung tissue peroxynitrite production and activate AMPK. Second, we tested whether loss of AMP-activated protein kinase alpha1 subunit in mouse would prevent enhanced oxidative stress and lung injury induced by ozone exposure.</p> <p>Methods</p> <p>Control and AMPKα1 deficient mice were exposed to ozone at a concentration of 2.0 ppm for 3 h in glass cages. Evaluation was performed 24 h after ozone exposure. Alveolar fluid clearance (AFC) was evaluated using fluorescein isothiocyanate tagged albumin. Differential cell counts, total protein levels, cytokine concentrations, myeloperoxidase activity and markers of oxidative stress, i.e. malondialdehyde and peroxynitrite, were determined in bronchoalveolar lavage (BAL) and lung homogenates (LH). Levels of AMPK-Thr¹⁷²phosphorylation and basolateral membrane Na(+)-K(+)-ATPase abundance were determined by Western blot.</p> <p>Results</p> <p>In control mice, ozone exposure induced lung inflammation as evidence by increased leukocyte count, protein concentration in BAL and myeloperoxidase activity, pro-inflammatory cytokine levels in LH. Increases in peroxynitrite levels (3 vs 4.4 nM, p = 0.02) and malondialdehyde concentrations (110 vs 230 μmole/g wet tissue) were detected in LH obtained from ozone-exposed control mice. Ozone exposure consistently increased phosphorylated AMPK-Thr¹⁷²to total AMPK ratio by 80% in control mice. Ozone exposure causes increases in AFC and basolateral membrane Na(+)-K(+)-ATPase abundance in control mice which did not occur in AMPKα1 deficient mice.</p> <p>Conclusions</p> <p>Our results collectively suggest that AMPK activation participates in ozone-induced increases in AFC, inflammation and oxidative stress. Further studies are needed to understand how the AMPK pathway may provide a novel approach for the prevention of ozone-induced lung injury.</p

JAK-STAT signaling in inflammatory breast cancer enables chemotherapy-resistant cell states

Inflammatory breast cancer (IBC) is a difficult-to-treat disease with poor clinical outcomes due to high risk of metastasis and resistance to treatment. In breast cancer, CD44+CD24- cells possess stem cell-like features and contribute to disease progression, and we previously described a CD44+CD24-pSTAT3+ breast cancer cell subpopulation that is dependent on JAK2/STAT3 signaling. Here we report that CD44+CD24- cells are the most frequent cell-type in IBC and are commonly pSTAT3+. Combination of JAK2/STAT3 inhibition with paclitaxel decreased IBC xenograft growth more than either agent alone. IBC cell lines resistant to paclitaxel and doxorubicin were developed and characterized to mimic therapeutic resistance in patients. Multi-omic profiling of parental and resistant cells revealed enrichment of genes associated with lineage identity and inflammation in chemotherapy resistant derivatives. Integrated pSTAT3 ChIP-seq and RNA-seq analyses showed pSTAT3 regulates genes related to inflammation and epithelial to mesenchymal transition (EMT) in resistant cells, as well as PDE4A, a cAMP-specific phosphodiesterase. Metabolomic characterization identified elevated cAMP signaling and CREB as a candidate therapeutic target in IBC. Investigation of cellular dynamics and heterogeneity at the single cell level during chemotherapy and acquired resistance by CyTOF and single cell RNA-seq identified mechanisms of resistance including a shift from luminal to basal/mesenchymal cell states through selection for rare pre-existing subpopulations or an acquired change. Lastly, combination treatment with paclitaxel and JAK2/STAT3 inhibition prevented the emergence of the mesenchymal chemo-resistant subpopulation. These results provide mechanistic rational for combination of chemotherapy with inhibition of JAK2/STAT3 signaling as a more effective therapeutic strategy in IBC