Search results for "Embryonic Structure"

Time-lapse technology: evaluation of embryo quality and new markers for embryo selection

2012

Current methods of embryo evaluation rely mainly on static observations of the embryo´s morphology. These observations are inevitably restricted to specific times and, considering that the development of the embryo is a dynamic process, several critical stages in between observations may go unnoticed. These methods are also very subjective, and variations between embryologists may affect critical decisions that will, in turn, affect the overall success of the IVF clinics. On the other hand, an increased number of multiple pregnancies calls for a reduction in the number of embryos transferred, making the selection procedure even more challenging for the embryologist. Therefore, new markers t…

2014

Oviparous females have three main options to increase their reproductive success: investing into egg number, egg mass and/or egg care. Although allocating resources to either of these three components is known to shape offspring number and size, potential trade-offs among them may have key impacts on maternal and offspring fitness. Here, we tested the occurrence of phenotypic trade-offs between egg number, egg mass and maternal expenditure on egg care in the European earwig, Forficula auricularia, an insect with pre- and post-hatching forms of maternal care. In particular, we used a series of laboratory observations and experiments to investigate whether these three components non-additivel…

Potential of human serum albumin as chiral selector of basic drugs in affinity electrokinetic chromatography-partial filling technique

2006

The enantiomeric resolution of compounds using HSA by means of affinity EKC (AEKC)-partial filling technique is the result of a delicate balance between different experimental variables such as protein concentration, running pH (background electrophoretic buffer (BGE), protein, and compound solutions), and plug length. In this paper, the possibility of using HSA as chiral selector for enantioseparation of 28 basic drugs using this methodology is studied. The effect of the physicochemical parameters, the structural properties of compounds, and compound-HSA protein binding percentages over their chiral resolution with HSA is outlined. Based on the results obtained, a decision tree is proposed…

Evaluación de las células de la blastema de aleta caudal como donantes en quimeras intraespecíficas de pez cebra

2008

The blastema is a regenerative tissue with remarkable pluripotency. The aim of this work done on zebrafish (Danio rerio) was to define technical procedures required for obtaining and integrating blastema cells into embryos at the mid blastula transition stage (MBT) and the effect on survival, as well as the capacity to produce pigmented chimaeras. Wild type blastema cells were injected into gold type MBT embryos (E). Wild MBT blastomere cells were also injected into gold type MBT embryos as a control (C1). A second control group, C2, was not subjected to any manipulation. Survival was evaluated at 24, 48 and 72 h after performing the chimaerism, and the rate of adult chimaeras evaluated. Th…

Cellular and molecular bases of biomineralization in sea urchin embryos

2013

Sea urchin embryos construct their skeleton following a precise gene-regulated time- and space-dependent programme, in concert with factors promoting cell adhesion and differentiation. The biomineral is deposited in a privileged extracellular space produced by the fused filopodia processes of the primary mesenchyme cells, the only cells producing a set of necessary matrix proteins. More than ten years ago we showed for the first time that signals from ectoderm cells promoted the expression of one of the major skeleton matrix genes by the primary mesenchyme cells. Since then, many of the crucial steps of this complex activation cascade, from ectoderm cells to embryonic spicules, have been el…

A survey on tubulin and arginine methyltransferase families sheds light on p. lividus embryo as model system for antiproliferative drug development

2019

Tubulins and microtubules (MTs) represent targets for taxane-based chemotherapy. To date, several lines of evidence suggest that effectiveness of compounds binding tubulin often relies on different post-translational modifications on tubulins. Among them, methylation was recently associated to drug resistance mechanisms impairing taxanes binding. The sea urchin is recognized as a research model in several fields including fertilization, embryo development and toxicology. To date, some &alpha

Prophenoloxidase activating system in tunicate hemolymph

1996

The activation sequence and related factors of the prophenoloxidase activating system in crustaceans was compared with the equivalent system in tunicates. Both solitary and colonial ascidians present in their hemolymph a copper-dependent phenoloxidase activity that may be inhibited by tropolone and phenylthiourea. Carbohydrates are able, to various extents, to trigger proPO system which requires serine protease cleavage for activation to phenoloxidase (PO). In some ascidians, hemocytes called ≪morula cells≫ show PO activity, while in Ciona intestinalis the ≪univacuolar refractile granulocytes≫ are positive after cytochemical staining with L-dopa. The relationships between proPO system and d…

The rise of thermophilic sea urchins and the expansion of barren grounds in the Mediterranean Sea

2011

Recent ecological studies have shown a strong relation between temperature, echinoids and their grazing effects on macro-algal communities. In this study, we speculate that climate warming may result in an increasingly favourable environment for the reproduction and development of the sea urchin Arbacia lixula. The relationship between increased A. lixula density and the extent of barren grounds in the Mediterranean Sea is also discussed.

Use of fresh vegetable discards as sea urchin diet: effect on gonad index and quality

2014

This study evaluated the exploitation of unprocessed agricultural discards in the form of fresh vegetable leaves as a diet for the sea urchin Paracentrotus lividus through the assessment of their effects on gonad yield and quality. A stock of wild-caught P. lividus was fed on discarded leaves from three different species (Beta vulgaris, Brassica oleracea, and Lactuca sativa) and the macroalga Ulva lactuca for 3 months under controlled conditions. At the beginning and end of the experiment, total and gonad weight were measured, while gonad and diet total carbon (C%), nitrogen (N%), δ13C, δ15N, carbohydrates, lipids, and proteins were analyzed. The results showed that agricultural discards pr…

Crushing predation of the spiny star Marthasterias glacialis upon the sea urchin Paracentrotus lividus

2009

Literature data report that only fish predators are able to crush sea urchin tests in Mediterranean rocky reefs. This experimental study showed that the spiny star Marthasterias glacialis is able to break Paracentrotus lividus tests and that the breaking event is more likely to occur for small-sized sea urchins than for big ones. Our results show that the role of M. glacialis in regulating P. lividus population density can be important in specific locations. They may have important implications, moreover, for the use of tethering techniques aimed at identifying predator types of sea urchins.