The Aggregation of Four Reconstructed Zygotes is the Limit to Improve the Developmental Competence of Cloned Equine Embryos

Embryo aggregation has been demonstrated to improve cloning efficiency in mammals. However, since no more than three embryos have been used for aggregation, the effect of using a larger number of cloned zygotes is unknown. Therefore, the goal of the present study was to determine whether increased numbers of cloned aggregated zygotes results in improved in vitro and in vivo embryo development in the equine. Zona-free reconstructed embryos (ZFRE''s) were cultured in the well of the well system in four different experimental groups: I. 1x, only one ZFRE per microwell; II. 3x, three per microwell; III. 4x, four per microwell; and IV. 5x, five ZFRE''s per microwell. Embryo size was measured on day 7, after which blastocysts from each experimental group were either a) maintained in culture from day 8 until day 16 to follow their growth rates, b) fixed to measure DNA fragmentation using the TUNEL assay, or c) transferred to synchronized mares. A higher blastocyst rate was observed on day 7 in the 4x group than in the 5x group. Non-aggregated embryos were smaller on day 8 compared to those aggregated, but from then on the in vitro growth was not different among experimental groups. Apoptotic cells averaged 10% of total cells of day 8 blastocysts, independently of embryo aggregation. Only pregnancies resulting from the aggregation of up to four embryos per microwell went beyond the fifth month of gestation, and two of these pregnancies, derived from experimental groups 3x and 4x, resulted in live cloned foals. In summary, we showed that the in vitro and in vivo development of cloned zona-free embryos improved until the aggregation of four zygotes and declined when five reconstructed zygotes were aggregated.     

Seasonal trends in whale shark Rhincodon typus sightings in an established tourism site in the Gulf of California,Mexico

The number of individual whale shark Rhincodon typus sightings registered October 2015–March 2018 in Bahia de La Paz, Mexico, ranged from 73 to 129 animals per season (total 1662), with the majority of them identified as males. Density plot maps showed high correlations in sightings between sample seasons and revealed potential hotspot areas. Our study provides an essential baseline of information for the management of whale shark conservation and the associated touristic activities in the region.     

An Unusual Pterosaur Specimen (Pterodactyloidea, ?Azhdarchoidea) from the Early Cretaceous Romualdo Formation of Brazil,and the Evolution of the Pterodactyloid Palate

A new and unusual specimen of a probable azhdarchoid pterosaur is described for the Early Cretaceous (Albian) Romualdo Formation of Brazil. The specimen consists of a palate that, although fragmentary, has a unique morphology differing from all other known pterosaurs with preservation of palatal elements. The new specimen probably indicates the presence of a yet undescribed pterodactyloid taxon for Romualdo Formation and brings new information on pterosaur diversity of this sedimentary unity. Mainly due to the rarity of pterodactyloid specimens with palate preservation, this structure has been overlooked in this clade. Here, we reassess the palatal anatomy of Pterodactyloidea, revealing an intriguing variety of morphotypes and evolutionary trends, some of them described here for the first time. The morphological disparity displayed by different pterodactyloid taxa may be further evidence of the presence of diverse feeding strategies within the clade.     

Symptomatic meningioma induced by cross-sex hormone treatment in a male-to-female transsexual

Transsexualism is defined as a strong conviction of belonging to the opposite sex in individuals without any physical intersex condition. Cross-sex hormone therapy is an important component of medical treatment of transexuals but it is not exempt from adverse effects.We report a case of a meningioma in a male-to-female transsexual patient treated with estrogens and cyproterone acetate for the past 4 years. He claimed recently severe headache and visual impairment. Blood tests showed normal results. A contrast-enhanced magnetic resonance imaging (MRI) scan revealed a mass in the tuberculum sellae consistent with a meningioma. Treatment was discontinued and tumor resection was performed. Histologic diagnosis confirmed strongly progesterone receptor-positive and estrogen negative meningioma. After surgery, the patient rejected the possibility of continuing with the treatment of estrogens and cyproterone, and so triptorelin (GnRH agonist) was initiated. At 1-year follow-up the patient's symptoms had ameliorated and a MRI scan revealed no recurrence of the tumor.This is the third case reported in the literature of a meningioma after treatment with estrogens and cyproterone acetate. We consider extremely important a long-term follow-up observation of male-to-female transsexual undergoing cross-sex hormone therapy in order to detect as soon as possible the adverse effects that can be derived from this therapy.     

Mitochondrial apoptosis induced by BH3‐only molecules in the exclusive presence of endoplasmic reticular Bak

Bak and Bax are critical apoptotic mediators that naturally localize to both mitochondria and the endoplasmic reticulum (ER). Although it is generally accepted that mitochondrial expression of Bak or Bax suffices for apoptosis initiated by BH3‐only homologues, it is currently unclear whether their reticular counterparts may have a similar potential. In this study, we show that cells exclusively expressing Bak in endoplasmic membranes undergo cytochrome c mobilization and mitochondrial apoptosis in response to BimEL and Puma, even when these BH3‐only molecules are also targeted to the ER. Surprisingly, calcium was necessary but not sufficient to drive the pathway, despite normal ER calcium levels. We provide evidence that calcium functions coordinately with the ER‐stress surveillance machinery IRE1α/TRAF2 to transmit apoptotic signals from the reticulum to mitochondria. These results indicate that BH3‐only mediators can rely on reticular Bak to activate an ER‐to‐mitochondria signalling route able to induce cytochrome c release and apoptosis independently of the canonical Bak,Bax‐dependent mitochondrial gateway, thus revealing a new layer of complexity in apoptotic regulation.     

Cell-Surface Lectins of Azospirillum spp.

Cell-surface lectins were screened in seven strains of Azospirillum brasilense and A. lipoferum. The presence of lectins was determined by particle agglutination assays employing latex beads coated with neoglycoproteins and by Western blot with neoglycoproteins labeled with horseradish peroxidase as a probe. Seven strains were agglutinated with the assayed sugar residues. The highest agglutination was with fucose and glucose and to a lesser extent with mannose residues. Cell-wall proteins extracted from two Azospirillum spp. strains exhibit lectin-like activities. We believe that lectins are present in the cell-wall of Azospirillum spp. Received: 23 June 1997 / Accepted: 23 September 1997     

Trafficking of glucose transporters-signals and mechanisms

The uptake of glucose into mammalian cells, catalysed by members of the GLUT family of glucose transporters, is regulated by a variety of hormones, growth factors and other agents. In adipocytes, skeletal muscle and heart the principal regulator is the hormone insulin, which rapidly stimulates glucose uptake by bringing about the translocation of the GLUT4 glucose transporter isoform from an intracellular vesicular compartment to the cell surface. Recent studies have implicated theC-terminal hydrophilic region of this protein as being primarily responsible for its insulin-regulated trafficking. In an attempt to identify the protein machinery involved in this trafficking, we have used glutathione S-transferase fusion proteins bearing hydrophilic domains of various GLUT transporters in affinity purification experiments on detergent-solubilized extracts of 3T3-L1 adipocyte intracellular membranes. TheC-terminal region of GLUT4 was found specifically to bind a number of polypeptides in these extracts, which are therefore candidates for components of the trafficking machinery. Although these proteins did not bind to the corresponding region of the more widely-distributed GLUT1 glucose transporter isoform, regulation of this transporter also appears to be of physiological importance in some cell types. To study such regulation we have used as a model system the interleukin-3 (IL-3)-dependent haemopoietic cell line IC.DP. These cells express a temperature-sensitive mutane of thev-abl tyrosine kinase, whose activation at the permissive temperature permits cell survival in the absence of IL-3 by suppression of apoptosis, although the growth factor is still required for proliferation. Both IL-3 and activation of the kinase were found to stimulate glucose transport by promoting the translocation of GLUT1 to the cell surface. Moreover, inhibition of glucose uptake by addition of transport inhibitors markedly increased the rate of apoptosis, an effect which could be reversed by the provision of alternative energy sources. These observations suggest that the trafficking of GLUT1, regulated by growth factors or oncogenes, may play an important role in the suppression of apoptosis in haemopoietic cells.     

Extension of the geographic range of Ateles chamek (Primates,Atelidae): evidence of river-barrier crossing by an amazonian primate

The black-faced black spider monkey (Ateles chamek) is endangered because of hunting and habitat loss. There are many gaps in our understanding of its geographic distribution. The Ucayali–Solimões–Amazon fluvial complex is currently recognized as the northern boundary of the species’ range, although published reports have indicated that it occurs north of the Rio Solimões. In this study we investigate published records, generate new field records, and assess the current information concerning the northern boundary of this species’ range. We conducted the study at the Mamirauá Sustainable Development Reserve in the central Brazilian Amazon, an area of 1,124,000 ha that consists entirely of Amazonian flooded forest (várzea). We collected data on the occurrence of the species from museum specimens and through field surveys, including interviews with local residents, direct observations, and the collection of new museum specimens. We confirmed the presence of A. chamek at 17 locations in the reserve, one of which was an island formed by a river bend cut-off that would have effectively taken any resident spider to the (new) north bank of the Solimões. We therefore conclude that fluvial dynamics were involved in creating the conditions for the dispersal and colonization of the species on the northern bank of the Rio Solimões. The data we present extends the known distribution of the species and increases its representation in protected areas.