Life History Traits of Sperm Whales Physeter macrocephalus Linnaeus, 1758 Stranded along Italian Coasts (Cetartiodactyla: Physeteridae)

We investigated the relationship between age and body length, and age at sexual maturity of Physeter macrocephalus individuals stranded along the Italian coast. Our molecular analysis shows that all our samples belong to the C.001.002 haplotype, shared between Atlantic and Mediterranean populations. We show that males attain sexual maturity at 10 years, similar to those from other marine areas. However, considering the same body length class, Mediterranean males are older than Atlantic ones. Our finding of a Mediterranean pregnant female of only 6.5 m in length and an assessed age of 24–26 years is particularly noteworthy, considering that females reach sexual maturity at about 9 years and 9 m of total length in other regions. Comparing our results with the literature data, we highlight the positive correlation between lifespan, adult body length and weight of males from the Mediterranean and Atlantic Ocean. Regardless of whether the relatively small size of Mediterranean specimens is a consequence of an inbreeding depression or an adaptation to less favorable trophic conditions, we recommend to closely monitor this population from a conservation perspective. In fact, its low genetic diversity likely corresponds to a relatively limited ability to respond to environmental changes compared with other populations

po 393 notch3 and cxcr4 cross signalling sustains acute t cell leukaemia progression

Introduction Acute T-cell lymphoblastic leukaemia (T-ALL) is a childhood cancer, characterised by infiltration of immature T-cells in bone marrow. Notch hyperactivation is a major driver of T-ALL development where CXCL12/CXCR4 axis plays an important role in T-ALL maintenance. In thymus the lympho-stromal communication drives progressive maturation of T-cells. Notch receptors regulate T-cell fate choices, dominating early steps of thymocyte maturation. In T-cell differentiation, Notch3, in association with pre-TCR and chemochine receptor CXCR4, govern the transition from double negative (DN) to double positive (DP) thymocytes. Previously, our laboratory demonstrated the lymphomagenic potential of Notch3 by creating a transgenic mouse model (N3-ICtg), characterised by the constitutive activation of the intracellular domain (IC) of Notch3 receptor (N3-IC) in immature thymocytes. In order to investigate the oncogenic cross-talk between Notch3 and CXCR4 in T-ALL progression, we analysed DP T-cells in different lymphoid compartments of N3-ICtg mice. Material and methods Freshly isolated cells from thymus, blood and bone marrow of N3-ICtg and WT mice were analysed by flow cytometry in order to verify the presence of DP T-cells and their cell-surface expression of CXCR4 and Notch3 receptors. Experiments in TALL1, a human T-ALL leukemic CD3 + /CD4 + /CD8 + cell line characterised by the activation of Notch3 and high expression of CXCR4, were also performed. TALL1 cells were treated with γ-secretase inhibitor (GSI) or their gene expression of Notch3 was silenced and then analysed by flow cytometry, RT-PCR and western blot. Statistical interpretation of the results was performed. Results and discussions DP-gated thymocytes obtained by N3-ICtg mice have shown a high co-expression of Notch3 and CXCR4 and a high migratory ability induced by SDF-1. An anomalous percentage representation of these DP T-cells at different ages in circulating blood, spleen and bone morrow may suggest an interaction between CXCR4 and Notch3 in T-ALL cell propagation. Experiments in human TALL1 cell line with Notch3 targeted inhibition suggest a modulated expression of CXCR4 through a β-arrestin1-mediated mechanism. CXCR4-antagonists treatment will further elucidate the molecular crosstalk between the two receptors. Conclusion Notch3 abnormal pathway, through boosting the expression of CXCR4 on cell-surface, may play a role in DP T-cells egress from thymus, and define a possible mechanism of 'pre-leukemic-cells' dissemination

N-Methyl-D-aspartic Acid (NMDA) in the nervous system of the amphioxus Branchiostoma lanceolatum

<p>Abstract</p> <p>Background</p> <p>NMDA (<it>N</it>-methyl-D-aspartic acid) is a widely known agonist for a class of glutamate receptors, the NMDA type. Synthetic NMDA elicits very strong activity for the induction of hypothalamic factors and hypophyseal hormones in mammals. Moreover, endogenous NMDA has been found in rat, where it has a role in the induction of GnRH (Gonadotropin Releasing Hormone) in the hypothalamus, and of LH (Luteinizing Hormone) and PRL (Prolactin) in the pituitary gland.</p> <p>Results</p> <p>In this study we show evidence for the occurrence of endogenous NMDA in the amphioxus <it>Branchiostoma lanceolatum</it>. A relatively high concentration of NMDA occurs in the nervous system of this species (3.08 ± 0.37 nmol/g tissue in the nerve cord and 10.52 ± 1.41 nmol/g tissue in the cephalic vesicle). As in rat, in amphioxus NMDA is also biosynthesized from D-aspartic acid (D-Asp) by a NMDA synthase (also called D-aspartate methyl transferase).</p> <p>Conclusion</p> <p>Given the simplicity of the amphioxus nervous and endocrine systems compared to mammalian, the discovery of NMDA in this protochordate is important to gain insights into the role of endogenous NMDA in the nervous and endocrine systems of metazoans and particularly in the chordate lineage.</p

Ecological Invasion, Roughened Fronts, and a Competitor's Extreme Advance: Integrating Stochastic Spatial-Growth Models

Both community ecology and conservation biology seek further understanding of factors governing the advance of an invasive species. We model biological invasion as an individual-based, stochastic process on a two-dimensional landscape. An ecologically superior invader and a resident species compete for space preemptively. Our general model includes the basic contact process and a variant of the Eden model as special cases. We employ the concept of a "roughened" front to quantify effects of discreteness and stochasticity on invasion; we emphasize the probability distribution of the front-runner's relative position. That is, we analyze the location of the most advanced invader as the extreme deviation about the front's mean position. We find that a class of models with different assumptions about neighborhood interactions exhibit universal characteristics. That is, key features of the invasion dynamics span a class of models, independently of locally detailed demographic rules. Our results integrate theories of invasive spatial growth and generate novel hypotheses linking habitat or landscape size (length of the invading front) to invasion velocity, and to the relative position of the most advanced invader.Comment: The original publication is available at www.springerlink.com/content/8528v8563r7u2742

Computational models in plant-pathogen interactions: the case of Phytophthora infestans

<p>Abstract</p> <p>Background</p> <p><it>Phytophthora infestans </it>is a devastating oomycete pathogen of potato production worldwide. This review explores the use of computational models for studying the molecular interactions between <it>P. infestans </it>and one of its hosts, <it>Solanum tuberosum</it>.</p> <p>Modeling and conclusion</p> <p>Deterministic logistics models have been widely used to study pathogenicity mechanisms since the early 1950s, and have focused on processes at higher biological resolution levels. In recent years, owing to the availability of high throughput biological data and computational resources, interest in stochastic modeling of plant-pathogen interactions has grown. Stochastic models better reflect the behavior of biological systems. Most modern approaches to plant pathology modeling require molecular kinetics information. Unfortunately, this information is not available for many plant pathogens, including <it>P. infestans</it>. Boolean formalism has compensated for the lack of kinetics; this is especially the case where comparative genomics, protein-protein interactions and differential gene expression are the most common data resources.</p