Sex-biased gene expression in the brown alga Fucus vesiculosus

Background The fucoid brown algae (Heterokontophyta, Phaeophyceae) are increasingly the focus of ecological genetics, biodiversity, biogeography and speciation research. The molecular genetics underlying mating system variation, where repeated dioecious – hermaphrodite switches during evolution are recognized, and the molecular evolution of sex-related genes are key questions currently hampered by a lack of genomic information. We therefore undertook a comparative analysis of male and female reproductive tissue transcriptomes against a vegetative background during natural reproductive cycles in Fucus vesiculosus. Results Over 300 k reads were assembled and annotated against public protein databases including a brown alga. Compared with the vegetative tissue, photosynthetic and carbohydrate metabolism pathways were under-expressed, particularly in male tissue, while several pathways involved in genetic information processing and replication were over-expressed. Estimates of sex-biased gene (SBG) expression were higher for male (14% of annotated orthologues) than female tissue (9%) relative to the vegetative background. Mean expression levels and variance were also greater in male- than female-biased genes. Major female-biased genes were carbohydrate-modifying enzymes with likely roles in zygote cell wall biogenesis and/or modification. Male-biased genes reflected distinct sperm development and function, and orthologues for signal perception (a phototropin), transduction (several kinases), and putatively flagella-localized proteins (including candidate gamete-recognition proteins) were uniquely expressed in males. Overall, the results suggest constraint on female-biased genes (possible pleiotropy), and less constrained male-biased genes, mostly associated with sperm-specific functions. Conclusions Our results support the growing contention that males possess a large array of genes regulating male fitness, broadly supporting findings in evolutionarily distant heterogametic animal models. This work identifies an annotated set of F. vesiculosus gene products that potentially regulate sexual reproduction and may contribute to prezygotic isolation, one essential step towards developing tools for a functional understanding of species isolation and differentiation.Peer Reviewe

Exopolysaccharide production by Helicobacter pylori

Helicobacter pylori is a widespread Gram-negative bacterium that infects the stomach of humans leading to the onset of several gastric disorders, such as, gastritis, gastric ulcers, and cancers. Studies from developing countries with low socioeconomic status and poor management of the drinking water suggest that it may serve as an environmental reservoir of H. pylori and therefore contribute to human infection. It has been reported that H. pylori has the ability to form microbial consortia embedded by a highly hydrated exopolysaccharidic matrix (biofilms) on surfaces exposed to water. The enhanced protection provided to microbial cells by the exopolysaccharides (EPS) brings added concerns about the possibility of H. pylori being transmitted through drinking water. H. pylori EPS as been reported to be composed mainly by Gal:Glc:GlcN in a proportion of 1.0:2.1:7.0, respectively (Stark et al., 1999). The present work brings about microscopical evidences of the capability of H. pilory to form free swimming bacterial aggregates and biofilms when submitted to nutrient depletion and hydrodynamic stress. Evidences that H. pylori aggregation is an exopolysaccharidic mediated phenomena both in planktonic and sessile states are also showed. Ethanol fractioning of the material recovered from these aggregates revealed an EPS composed of Gal:Glc:GlcN in a proportion of 1.0:0.4:1.6 respectively. A further structural detail about this EPS is under progress

BSA-PEG Hydrogel: A Novel Protein-Ligand Binding 3D Matrix

Hydrogel materials have good biomimetic properties and high potential for biomedical and bioanalytical applications. In this work, a hydrogel of serum albumin crosslinked with poly-(ethylene glycol) was prepared and characterized for its water content, protein structure and stability. The ability of the hydrogel to bind small molecule ligands with different hydrophobicity was evaluated using a homologous series of amphiphiles (NBD-Cn, n = 4, 6 and 8) and the calculated binding affinities were similar to that of free protein in solution. Overall, the results indicate this type of hydrogel system as a convenient tool for studying the binding of xenobiotics to tissue proteins.info:eu-repo/semantics/publishedVersio

Degradation of lithium Iron phosphate-based cathode in lithium-ion batteries: a post-mortem analysis

Commercial Li-ion batteries were studied in view to investigate the degradation of the positive electrode in an end-of-life battery condition. Post-mortem analyses were performed by using SEM and DRX techniques; structural and morphological changes after prolonged cycling were evaluated comparatively to a fresh cathode sample. The cycling procedure based on a constant current (CC)/constant voltage (CV) charge and CC discharge was executed, being the condition of end-of-life battery achieved after submitting the Li-ion battery to nearly 2000 charge/discharge cycles. EDS analysis revealed zirconium element as the dopant of a LiFePO4-based cathode of the battery under study. According to X-ray diffraction results for the fresh (charged condition) cathode, the positive electrode includes in its constitution a mixture of crystalline compounds, LiFePO4 and FePO4. SEM images displayed and DRX patterns obtained for the cycled cathode showed modifications compared to the fresh cathode results, evidencing the degradation of the battery at the end-of-life: decrease in the density of microparticles associated to areas where the insertion/de-insertion occurs; decrease of the LiFePO4/FePO4 ratio; both results pointed out to the occurrence of battery loss capacity with the imposed charge/discharge cycles

Concentraciones de nutrientes en aguas costeras: impacto del Río Guadiana

Water samples were collected over an area of 900 km(2) adjacent to the outflow of the Guadiana River in January 1999 to characterize the concentrations and spatial distribution of nutrients (ammonium, nitrite, nitrate, phosphate and silicate) in the water column. The purpose of the study was to characterize a winter situation of low discharge in terms of nutrient concentrations in the coastal area adjacent to the Guadiana outflow, before the reduction of the river flow due to the completion of the Alqueva Dam. The results show that the maximum influence of the Guadiana outflow was close to the mouth of the Guadiana River, where the highest nutrient concentrations and the minimum of salinity were registered. At the surface, the nutrient concentrations decreased gradually as the distance from the coast increased. The influence of the Guadiana outflow at the surface, despite being small, was evident in the area of about 90 km(2) that extends westwards from the mouth of the river. In this area, the increase in N compounds was more significant than in P and Si. The vertical influence of the outflow of the Guadiana River, until over the isobath lower than 30 m, was reflected in nutrient concentrations that decreased with the increase in depth. However, when the depth of the water column was greater than 30 m, the nutrient concentrations increased with the increase in depth. It is expected that with the completion of the Alqueva Dam, the outflow of the Guadiana River will be reduced even further. Nutrient concentrations will also be reduced and the influence of the river in the coastal zone will be even smaller. This could have a negative impact on the nutrient biogeochemical cycles and on the overall productivity of the area.En un área de 900 km2 alrededor de la desembocadura del Río Guadiana se recolectaron muestras de agua para caracterizar las concentraciones y distribución espacial de nutrientes (amonio, nitritos, nitratos, fosfatos y silicatos) en la columna de agua. El propósito de este estudio fue caracterizar la condición invernal de pocas descargas, en términos de concentración de nutrientes en el área costera adyacente a la desembocadura del Guadiana, antes de que el flujo del río se vea reducido por la conclusión de la Presa Alqueva. Los resultados indican que la mayor influencia de la descarga del Guadiana se observó cerca de la boca del río, donde se registraron las mayores concentraciones de nutrientes y la salinidad más baja. En superficie, las concentraciones de nutrientes disminuyeron gradualmente con el aumento de la distancia a la costa. La influencia de la descarga del Guadiana en superficie, aunque pequeña, fue evidente en el área de ~90 km2 que se extiende de la boca del río hacia el oeste. En esta área el incremento de compuestos de N fue más significativo que el de los de P y Si. La influencia vertical de la descarga del Río Guadiana, hasta por encima de la isóbata < 30 m se reflejó en las concentraciones de nutrientes que disminuyeron conforme aumentaba la profundidad. Sin embargo, cuando la profundidad de la columna de agua era > 30 m las concentraciones de nutrientes aumentaron con la profundidad. Es de esperar que con la terminación de la Presa Alqueva la descarga del río se vea aún más disminuida. Las concentraciones también se verán reducidas y la influencia del río en la zona costera será aún menor. Esto podría tener un impacto negativo en los ciclos biogeoquímicos de nutrientes y en la productividad global del área.proyecto SIRIA, financiado conjuntamente entre el Ministerio de Defensa y la Fundación de las Universidades de Portugal, en el marco del Programa Medio Ambiente y Defensainfo:eu-repo/semantics/publishedVersio

Development of fast dissolving polymer-based microneedles for delivery of an antigenic melanoma cell membrane

Delivery of cancer cell membranes (CM) is a new approach for the activation of the immune system and the induction of immunotherapy of cancer. Local delivery of melanoma CM into skin can induce efficient immune stimulation of antigen presenting cells (APCs), such as dendritic cells. In the current study, fast dissolving microneedles (MNs) were developed for the delivery of melanoma B16F10 CM. Two polymers were tested for the fabrication of MNs: poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) and hyaluronic acid (HA). The incorporation of CM in MNs was achieved through coating of the MNs using a multi-step layering procedure or the micromolding technique. The CM loading and its stabilization were improved by adding sugars (sucrose and trehalose) and a surfactant (Poloxamer 188), respectively. In an ex vivo experiment, both PMVE-MA and HA showed fast dissolutions (&lt;30 s) after insertion into porcine skin. However, HA-MA showed better mechanical properties, namely improved resistance to fracture when submitted to a compression force. Overall, a B16F10 melanoma CM-dissolving MN system was efficiently developed as a promising device suggesting further studies in immunotherapy and melanoma applications

Development of fast dissolving polymer-based microneedles for delivery of an antigenic melanoma cell membrane

Delivery of cancer cell membranes (CM) is a new approach for the activation of the immune system and the induction of immunotherapy of cancer. Local delivery of melanoma CM into skin can induce efficient immune stimulation of antigen presenting cells (APCs), such as dendritic cells. In the current study, fast dissolving microneedles (MNs) were developed for the delivery of melanoma B16F10 CM. Two polymers were tested for the fabrication of MNs: poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) and hyaluronic acid (HA). The incorporation of CM in MNs was achieved through coating of the MNs using a multi-step layering procedure or the micromolding technique. The CM loading and its stabilization were improved by adding sugars (sucrose and trehalose) and a surfactant (Poloxamer 188), respectively. In an ex vivo experiment, both PMVE-MA and HA showed fast dissolutions (&lt;30 s) after insertion into porcine skin. However, HA-MA showed better mechanical properties, namely improved resistance to fracture when submitted to a compression force. Overall, a B16F10 melanoma CM-dissolving MN system was efficiently developed as a promising device suggesting further studies in immunotherapy and melanoma applications

Development of fast dissolving polymer-based microneedles for delivery of an antigenic melanoma cell membrane

Delivery of cancer cell membranes (CM) is a new approach for the activation of the immune system and the induction of immunotherapy of cancer. Local delivery of melanoma CM into skin can induce efficient immune stimulation of antigen presenting cells (APCs), such as dendritic cells. In the current study, fast dissolving microneedles (MNs) were developed for the delivery of melanoma B16F10 CM. Two polymers were tested for the fabrication of MNs: poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) and hyaluronic acid (HA). The incorporation of CM in MNs was achieved through coating of the MNs using a multi-step layering procedure or the micromolding technique. The CM loading and its stabilization were improved by adding sugars (sucrose and trehalose) and a surfactant (Poloxamer 188), respectively. In an ex vivo experiment, both PMVE-MA and HA showed fast dissolutions (&lt;30 s) after insertion into porcine skin. However, HA-MA showed better mechanical properties, namely improved resistance to fracture when submitted to a compression force. Overall, a B16F10 melanoma CM-dissolving MN system was efficiently developed as a promising device suggesting further studies in immunotherapy and melanoma applications

Development of fast dissolving polymer-based microneedles for delivery of an antigenic melanoma cell membrane

Delivery of cancer cell membranes (CM) is a new approach for the activation of the immune system and the induction of immunotherapy of cancer. Local delivery of melanoma CM into skin can induce efficient immune stimulation of antigen presenting cells (APCs), such as dendritic cells. In the current study, fast dissolving microneedles (MNs) were developed for the delivery of melanoma B16F10 CM. Two polymers were tested for the fabrication of MNs: poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) and hyaluronic acid (HA). The incorporation of CM in MNs was achieved through coating of the MNs using a multi-step layering procedure or the micromolding technique. The CM loading and its stabilization were improved by adding sugars (sucrose and trehalose) and a surfactant (Poloxamer 188), respectively. In an ex vivo experiment, both PMVE-MA and HA showed fast dissolutions (&lt;30 s) after insertion into porcine skin. However, HA-MA showed better mechanical properties, namely improved resistance to fracture when submitted to a compression force. Overall, a B16F10 melanoma CM-dissolving MN system was efficiently developed as a promising device suggesting further studies in immunotherapy and melanoma applications

Development of fast dissolving polymer-based microneedles for delivery of an antigenic melanoma cell membrane

Delivery of cancer cell membranes (CM) is a new approach for the activation of the immune system and the induction of immunotherapy of cancer. Local delivery of melanoma CM into skin can induce efficient immune stimulation of antigen presenting cells (APCs), such as dendritic cells. In the current study, fast dissolving microneedles (MNs) were developed for the delivery of melanoma B16F10 CM. Two polymers were tested for the fabrication of MNs: poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) and hyaluronic acid (HA). The incorporation of CM in MNs was achieved through coating of the MNs using a multi-step layering procedure or the micromolding technique. The CM loading and its stabilization were improved by adding sugars (sucrose and trehalose) and a surfactant (Poloxamer 188), respectively. In an ex vivo experiment, both PMVE-MA and HA showed fast dissolutions (&lt;30 s) after insertion into porcine skin. However, HA-MA showed better mechanical properties, namely improved resistance to fracture when submitted to a compression force. Overall, a B16F10 melanoma CM-dissolving MN system was efficiently developed as a promising device suggesting further studies in immunotherapy and melanoma applications