lga972: a cross-platform application for optimizing LD studies using a genetic algorithm

lga972 is a user-friendly cross-platform application with a graphical interface for determining the design features of two-stage genetic linkage disequilibrium studies that minimize the genotyping burden.     

Effect of different cryoprotectants and vitrificant solutions on the hatching rate of turbot embryos (Scophthalmus maximus)

Vitrification could provide a promising tool for the cryopreservation of fish embryos. However, in order to achieve a vitrifiable medium, a high concentration of permeable cryoprotectants must be employed, and the incorporation of high molecular weight compounds should also be considered. The toxicity of these permeable and non-permeable agents has to be assessed, particularly when high concentrations are required. In the present study, permeable and non-permeable cryoprotectant toxicity was determined in turbot embryos at two development stages (F stage-tail bud and G stage-tail bud free). Embryos treated with pronase (2mg/ml, 10 min at 22 degrees C) were incubated in dimethyl sulfoxide (Me2SO), methanol (Meth.) or ethylene glycol (EG) in concentrations ranging from 0.5 to 6M for periods of 10 or 30 min, and in 5, 10, and 15% polyvinylpyrrolidone (PVP), 10, 15, and 20% sucrose or 0.1, 1, and 2% X-1000 for 2 min. The embryos were then washed well and incubated in seawater until hatching. The toxicity of permeable cryoprotectants increased with concentration and exposure time. There were no significant differences between permeable cryoprotectants. However, embryos tolerated higher concentrations of Me2SO than other cryoprotectants. Exposure to permeable cryoprotectants did not affect the hatching rate except at G stage with X-1000 treatment and 20% sucrose. Taking into account the cryoprotectant toxicity and the vitrification ability of cryoprotectant mixtures, three vitrification solutions (V1, V2, and V3), and one protocol for stepwise incorporation were designed. The tested solutions contained 5M Me2SO+2M Meth+1M EG plus 5% PVP, 10% sucrose or 2% X-1000. The hatching rate of embryos that had been exposed to the the vitrification solutions was analyzed and no significant differences were noticed compared with the controls. Our results demonstrate that turbot embryos can be subject to this cryoprotectant protocol without deleterious effect on the hatching rate.     

A study on the microbiota from olive-mill wastewater (OMW) disposal lagoons, with emphasis on filamentous fungi and their biodegradative potential

The microbial composition of olive mill wastewater (OMW) from four disposal ponds has been studied. Such OMW samples contained a variable (but high) number of bacteria, yeasts and molds. Among the latest, members of twelve different genera (Acremonium, Alternaria, Aspergillus, Chalara, Fusarium, Lecytophora, Paecilomyces, Penicillium, Phoma, Phycomyces, Rhinocladiella and Scopulariopsis) were found. Members of five genera (Chalara, Fusarium, Paecilomyces, Penicillium and Scopulariopsis) were widely distributed, and they were able to grow efficiently in undiluted OMW as a sole source of nutrients. Strains of Fusarium, Paecilomyces, Penicillium and Scopulariopsis showed a marked capacity for OMW detoxification, depleting its antibacterial activity almost completely.     

Effects of culture conditions on production of antibiotically active metabolites by the marine alga Spyridia filamentosa (Ceramiaceae, Rhodophyta). I. Light

The effect of irradiance over the range 5 to 70 μmol photon m-2 s-1 on production of antibiotically active metabolites was assessed for male and female gametophytes and tetrasporophytes of the red alga Sphyridia filamentosa (Wulfen) Harvey in Hooker in culture. Whole-algal extracts and ten recognizable TLC-separable zones were assayed against five human microorganisms pathogenic to humans. For all experimental irradiance conditions, the ten TLC zones displayed activity against four of the microorganisms. The maximum number of TLC zones with activity under any of the culture conditions was six each for male and female Spyridia at 70 μmol photon m-2 s-1. Small changes in irradiance resulted both in different activities against specific microorganisms and degree of activity. The fact that every TLC zone showed differing activities at different light conditions or when extracted from different life history stages strongly suggests the presence of multiple antibiotic principals in individual TLC zones. This revised version was published online in June 2006 with corrections to the Cover Date.     

Isolation of neurocysticercosis-related antigens from a genomic phage display library of Taenia solium

In this study, the authors have generated a tapeworm Taenia solium genomic DNA expression library where foreign peptides/proteins were fused to N-termini of M13 cpVIII and expressed at a high copy number on the phage surface, and they showed that this library may be used in bioselection against antipathogen immune sera, allowing the identification of disease-related antigens recognizing antibodies present in clinical samples. They isolated 2 phage clones expressing T. solium-derived antigens specifically reacting with antibodies present in plasma and cerebrospinal fluid samples of neuroimaging-confirmed neurocysticercosis patients. The described antigen discovery strategy may be used for the direct identification of antigens useful for host-pathogen interaction studies as well as for the development of molecular vaccines and diagnostics.     

The effect of developmental stage on eggshell thickness variation in endangered falcons

We compared eggshell thickness of hatched eggs with that of non-developed eggs in endangered falcon taxa to explore the effect of embryo development on eggshell thinning. To our knowledge, this has never been examined before in falcons, despite the fact that eggshell thinning due to pollutants and environmental contamination is often considered the most common cause of egg failure in falcons. Because of the endangered nature of these birds, and the difficulty in gaining access to the nests and their eggs, there is a large gap in our knowledge regarding eggshell thickness variation and the factors affecting it. We used a linear mixed-effects (LME) model to explore the variation in eggshell thickness (n = 335 eggs) in relation to the developmental stage of the eggs, but also in relation to the falcon taxa, the laying sequence and the study zone. Female identity (n = 69) and clutch identity (n = 98) were also included in the LME model. Our results are consistent with the prediction that eggshell thickness decreases during incubation because of the important effect of calcium uptake by the embryo during development. Our results also show that eggs laid later in the sequence had significantly thinner eggshells. In this study, we provide the first quantitative data on eggshell thickness variation of hatched eggs in different falcon taxa that were not subjected to contamination or food limitation (i.e., bred under captive conditions). Because eggshell thickness strongly influences survival and because the species examined in this study are endangered, our data represent a valuable control for future studies on the effects of pollution on eggshells from wild populations and thus are an important contribution to the conservation of falcons.     

A new species of Pliopithecus Gervais, 1849 (Primates: Pliopithecidae) from the Middle Miocene (MN8) of Abocador de Can Mata (els Hostalets de Pierola,Catalonia, Spain)

Pliopithecus (Pliopithecus) canmatensis sp. nov. is described from several Late Aragonian localities from Abocador de Can Mata (ACM) in els Hostalets de Pierola (Vallès‐Penedès Basin, Catalonia, Spain), spanning from ～11.7 to 11.6 Ma (C5r.3r subchron), and being correlated to the MN8 (reference locality La Grive L3). The ACM remains display a pliopithecine dental morphology with well‐developed pliopithecine triangles on M/2 and M/3. This, together with other occlusal details, negates an attribution to the subgenus Epipliopithecus. Although slightly smaller, the ACM remains are most similar in size to comparable elements of P. piveteaui and P. antiquus. Several occlusal details (such as the greater development of the buccal cingulid in lower molars) and dental proportions (M/3 much longer than M/2), however, indicate greater similarities with P. antiquus from Sansan and La Grive. The ACM remains, however, differ from P. antiquus in dental proportions as well as occlusal morphology of the lower molars (including the less peripheral position of the protoconid and more medial position of the hypoconulid, the more mesial position of the buccal cuspids as compared to the lingual ones, the narrower but distinct mesial fovea, the higher trigonid, and the more extensive buccal cingulid, among others). These differences justify a taxonomic distinction at the species level of the ACM pliopithecid remains with respect to P. antiquus. Previous pliopithecid findings from the Vallès‐Penedès Basin, previously attributed to P. antiquus, are neither attributable to the latter species nor to the newly erected one. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.     

Focusing on optic tectum circuitry through the lens of genetics

The visual pathway is tasked with processing incoming signals from the retina and converting this information into adaptive behavior. Recent studies of the larval zebrafish tectum have begun to clarify how the 'micro-circuitry' of this highly organized midbrain structure filters visual input, which arrives in the superficial layers and directs motor output through efferent projections from its deep layers. The new emphasis has been on the specific function of neuronal cell types, which can now be reproducibly labeled, imaged and manipulated using genetic and optical techniques. Here, we discuss recent advances and emerging experimental approaches for studying tectal circuits as models for visual processing and sensorimotor transformation by the vertebrate brain.     

Enterocyte proliferation and intestinal hyperplasia induced by simian virus 40 T antigen require a functional J domain

Transgenic mice expressing the simian virus 40 large T antigen (TAg) in enterocytes develop intestinal hyperplasia that progresses to dysplasia with age. This induction requires TAg action on the retinoblastoma (Rb) family of tumor suppressors and is independent of the p53 pathway. In cell culture systems, the inactivation of Rb proteins requires both a J domain in TAg that interacts with hsc70 and an LXCXE motif that directs association with Rb proteins. Together these elements are sufficient to release E2Fs from their association with Rb family members. We have generated transgenic mice that express a J domain mutant (D44N) in villus enterocytes. In contrast to wild-type TAg, the D44N mutant is unable to induce enterocyte proliferation. Histological and morphological examination revealed that mice expressing the J domain mutant have normal intestines without loss of growth control. Unlike mice expressing wild-type TAg, mice expressing D44N do not reduce the protein levels of p130 and are also unable to dissociate p130-E2F DNA binding complexes. Furthermore, mice expressing D44N in a null p130 background are still unable to develop hyperplasia. These studies demonstrate that the ectopic proliferation of enterocytes by TAg requires a functional J domain and suggest that the J domain is necessary to inactivate all three pRb family members.