Three species of entomopathogenic nematodes of the family Steinernematidae (Nematoda: Rhabditida) new to continental Portugal

Abstract In order to determine the species of entomopathogenic nematodes in Continental Portugal, a survey was conducted in the country. Nematodes were recovered from soil samples collected from Alentejo, Algarve, center and the north of Portugal from 2006-2009. Isolates were identified based on morphology and sequence analysis. Phylogenetic analysis was based on sequences of partial 28S (D2D3), internal transcribed spacer (ITS) and cytochrome oxidase c subunit I gene (COX I). Isolates 59F, 15G, 20F and 2B were characterized in detail. Isolate 2B shows a morphology identical to Steinernema intermedium which is a member of the affine/intermedium-group and is characterized by the presence of strongly curved and robust spicules with a distinct rostrum, in the male, and dorsal tail depression in third-stage infective junveniles (IJ). However, the phylogenies based on the three molecular markers revealed that isolate 2B is more closely related to S. affine than with S. intermedium. The morphological results for isolate 20F identify it as S. kraussei which is a member of kraussei/feltiae–group, characterized by IJs with a straight body of medium length (mean = 700–950 μm), lateral field mostly with eight ridges, rather broad, flatly rounded and continuous cephalic region, excretory pore at level of mid-pharynx; males with mucronate tail, yellowish spicules ca. 50 μm long and wide manubria; females with short conoid tail with pointed non-mucronate tip. Based on morphology and sequence analysis, isolates 59F and 15G were considered conspecific and identified as a species belonging to the glaseri–group. More detailed studies are necessary to solve if these isolates represent a new species

Nrf2, a PPARγ Alternative Pathway to Promote CD36 Expression on Inflammatory Macrophages: Implication for Malaria

CD36 is the major receptor mediating nonopsonic phagocytosis of Plasmodium falciparum-parasitized erythrocytes by macrophages. Its expression on macrophages is mainly controlled by the nuclear receptor PPARγ. Here, we demonstrate that inflammatory processes negatively regulate CD36 expression on human and murine macrophages, and hence decrease Plasmodium clearance directly favoring the worsening of malaria infection. This CD36 downregulation in inflammatory conditions is associated with a failure in the expression and activation of PPARγ. Interestingly, using siRNA mediating knock down of Nrf2 in macrophages or Nrf2- and PPARγ-deficient macrophages, we establish that in inflammatory conditions, the Nrf2 transcription factor controls CD36 expression independently of PPARγ. In these conditions, Nrf2 activators, but not PPARγ ligands, enhance CD36 expression and CD36-mediated Plasmodium phagocytosis. These results were confirmed in human macrophages and in vivo where only Nrf2 activators improve the outcome of severe malaria. Collectively, this report highlights that the Nrf2 transcription factor could be an alternative target to PPARγ in the control of severe malaria through parasite clearance

The Light Responsive Transcriptome of the Zebrafish: Function and Regulation

Most organisms possess circadian clocks that are able to anticipate the day/night cycle and are reset or “entrained” by the ambient light. In the zebrafish, many organs and even cultured cell lines are directly light responsive, allowing for direct entrainment of the clock by light. Here, we have characterized light induced gene transcription in the zebrafish at several organizational levels. Larvae, heart organ cultures and cell cultures were exposed to 1- or 3-hour light pulses, and changes in gene expression were compared with controls kept in the dark. We identified 117 light regulated genes, with the majority being induced and some repressed by light. Cluster analysis groups the genes into five major classes that show regulation at all levels of organization or in different subset combinations. The regulated genes cover a variety of functions, and the analysis of gene ontology categories reveals an enrichment of genes involved in circadian rhythms, stress response and DNA repair, consistent with the exposure to visible wavelengths of light priming cells for UV-induced damage repair. Promoter analysis of the induced genes shows an enrichment of various short sequence motifs, including E- and D-box enhancers that have previously been implicated in light regulation of the zebrafish period2 gene. Heterologous reporter constructs with sequences matching these motifs reveal light regulation of D-box elements in both cells and larvae. Morpholino-mediated knock-down studies of two homologues of the D-box binding factor Tef indicate that these are differentially involved in the cell autonomous light induction in a gene-specific manner. These findings suggest that the mechanisms involved in period2 regulation might represent a more general pathway leading to light induced gene expression

Understanding complexity in the HIF signaling pathway using systems biology and mathematical modeling

Hypoxia is a common micro-environmental stress which is experienced by cells during a range of physiologic and pathophysiologic processes. The identification of the hypoxia-inducible factor (HIF) as the master regulator of the transcriptional response to hypoxia transformed our understanding of the mechanism underpinning the hypoxic response at the molecular level and identified HIF as a potentially important new therapeutic target. It has recently become clear that multiple levels of regulatory control exert influence on the HIF pathway giving the response a complex and dynamic activity profile. These include positive and negative feedback loops within the HIF pathway as well as multiple levels of crosstalk with other signaling pathways. The emerging model reflects a multi-level regulatory network that affects multiple aspects of the physiologic response to hypoxia including proliferation, apoptosis, and differentiation. Understanding the interplay between the molecular mechanisms involved in the dynamic regulation of the HIF pathway at a systems level is critically important in defining new appropriate therapeutic targets for human diseases including ischemia, cancer, and chronic inflammation. Here, we review our current knowledge of the regulatory circuits which exert influence over the HIF response and give examples of in silico model-based predictions of the dynamic behaviour of this system

Obesity, inflammation, and insulin resistance

White adipose tissue (WAT) is considered an endocrine organ. When present in excess, WAT can influence metabolism via biologically active molecules. Following unregulated production of such molecules, adipose tissue dysfunction results, contributing to complications associated with obesity. Previous studies have implicated pro- and anti-inflammatory substances in the regulation of inflammatory response and in the development of insulin resistance. In obese individuals, pro-inflammatory molecules produced by adipose tissue contribute to the development of insulin resistance and increased risk of cardiovascular disease. On the other hand, the molecules with anti-inflammatory action, that have been associated with the improvement of insulin sensitivity, have your decreased production. Imbalance of these substances contributes significantly to metabolic disorders found in obese individuals. The current review aims to provide updated information regarding the activity of biomolecules produced by WAT

Scanning electron microscope study of morphological modifications of lateral fields of infective juveniles of mutant Steinernema feltiae (Filipjev) (Rhabditida : Steinernematidae)

Les résultats relatés concernent une étude détaillée en microscopie électronique à balayage des modifications morphologiques observées dans les champs latéraux des juvéniles infestants de divers mutants de #Steinernema feltiae obèses Sfdpy-1(pn7, pn11, pn29 et pn31), segmentés Sfseg-1(pn12), et un double mutant, obèse + segmenté Sfdpy-1(pn7)Sfseg-1(pn12). Les champs latéraux de tous les mutants examinés diffèrent significativement de ceux des individus de type sauvage. Les modifications observées concernent un large spectre de changements morphologiques, ainsi que la disparition ou le nombre des lignes individuelles. Une action mutagène combinée des deux gènes Sfdpy-1 et Sfseg-1 observée chez les mutants doubles élargit de plus la variabilité observée. Cette action produit en effet des irrégularités plus prononcées dans la morphologie et la disposition des lignes que celles produites par l'action des mutations parentales agissant seules. L'étendue de la variation provoquée chez le nématode mutant apparaît spécifique du gène, mais non de l'allèle. Bien que les modifications morphologiques diffèrent significativement entre les juvéniles infestants comportant des mutations liées aux gènes Sfdy-1 et Sfseg-1, les changements observés chez des spécimens comportant différents allèles mutants du gène Sfdy-1 sont assez semblables. Etant donné que des champs latéraux distincts sont, chez #S. feltiae, spécifiques des "dauer larvae", les résultats obtenus suggèrent que l'un et l'autre gènes mis en cause pourraient jouer un rôle significatif dans le processus de formation de la cuticule chez les "dauer larvae" de ces nématodes. (Résumé d'auteur

Steinernema cubana sp.n. (Nematoda : Rhabditida : Steinernematidae) and the preliminary characterization of its associated bacterium

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