Biomonitoring Assessment of Toxic and Trace Elements in Sterechinus neumayeri Sea Urchins from the Comandante Ferraz Station in Antarctica.

In the present study, sea urchin Sterechinus neumayeri tissues were used for the passive biomonitoring of toxic and trace elements at the Comandante Ferraz Station, Antarctica and compared to a pristine region (Botany). As, Ba, Br, Ca, Co, Cr, Fe, K, Na, Rb, Sc, Se and Zn concentrations were determined by instrumental neutron activation analysis (INAA), while toxic metals (Cd, Hg, Ni and Pb), and Cu were determined by atomic absorption spectrometry (GF-AAS). The findings were compared to other organisms commonly applied for biomonitoring purposes and to the sediment concentrations of each sampling region. Urchins from the Ferraz Station area presented higher Br, Co, Cr, Cs, K, Se and Zn levels than the pristine location. The results obtained herein suggest S. neumayeri can be applied to the biomonitoring of Cr and Zn. The present study also contributes to knowledge of the mineral composition of the sea urchin S. neumayeri.

Construction of a mammalian embryo model from stem cells organized by a morphogen signalling centre.

Generating properly differentiated embryonic structures in vitro from pluripotent stem cells remains a challenge. Here we show that instruction of aggregates of mouse embryonic stem cells with an experimentally engineered morphogen signalling centre, that functions as an organizer, results in the development of embryo-like entities (embryoids). In situ hybridization, immunolabelling, cell tracking and transcriptomic analyses show that these embryoids form the three germ layers through a gastrulation process and that they exhibit a wide range of developmental structures, highly similar to neurula-stage mouse embryos. Embryoids are organized around an axial chordamesoderm, with a dorsal neural plate that displays histological properties similar to the murine embryo neuroepithelium and that folds into a neural tube patterned antero-posteriorly from the posterior midbrain to the tip of the tail. Lateral to the chordamesoderm, embryoids display somitic and intermediate mesoderm, with beating cardiac tissue anteriorly and formation of a vasculature network. Ventrally, embryoids differentiate a primitive gut tube, which is patterned both antero-posteriorly and dorso-ventrally. Altogether, embryoids provide an in vitro model of mammalian embryo that displays extensive development of germ layer derivatives and that promises to be a powerful tool for in vitro studies and disease modelling.

Prebiotic effects of inulin extracted from burdock (Arctium lappa) in broilers / Efeito prebiótico da inulina extraída da bardana (Arctium lappa) em frangos de corte

The aim of this study was to evaluate the prebiotic effect of burdock (Arctium lappa) in commercial poultry. Four experiments were conducted to evaluate the performance parameters and the protection after challenge with Salmonella Enteritidis and Salmonella Kedougou, with and without Bifidobacterium probiotic. In two trials, the chickens were fed with flour burdock 1% during 42 days. In the other two, the chickens were fed with fructan extracted from burdock (inulin), by gavage, at a concentration of 100 mg/bird, during the first three days of life. The results showed that the broilers treated with burdock flour showed underperformed, with less weight gain from the second week, and the worst results in the fattening stage. The treated birds had diarrhea and impaired intestinal integrity. However, the groups treated with the flour had a lower rate of intestinal colonization by Salmonella Kedougou, after challenge. No statistically significant differences were detected in the performance parameters of broilers receiving the inulin, and the morphometric analysis showed no lesions in the intestinal villi. However, there was no protection in the challenge with Salmonella Enteritidis, regardless of association with probiotic. These results demonstrated that the manner of administration has influence on the prebiotic effect of burdock. The burdock flour was administered for 42 days, which may have influenced intestinal mucosal injury. Instead, the inulin was given only in the first three days, which may have been insufficient for protection against Salmonella. New experiments are needed to determine an able formulation for a protective effect, without negative impact on growth, weight gain and feed conversion of the supplemented animals.(AU)

Este projeto teve por objetivo avaliar o efeito prebiótico da bardana (Arctium lappa) em aves comerciais. Foram realizados quatro experimentos para avaliar os parâmetros zootécnicos e o grau de proteção após o desafio com Salmonella Kedougou e Salmonella Enteritidis, com e sem a adição de probióticos à base de Bifidobacterium. Em dois experimentos, as aves receberam a farinha de bardana 1% na ração, durante 42 dias. Nos outros dois, as aves receberam o frutano extraído da bardana (inulina), por gavagem, na concentração de 100 mg/ave, nos três primeiros dias de vida. Os resultados demonstraram que os frangos tratados com farinha de bardana apresentaram desempenho zootécnico inferior ao controle, com menor ganho de peso a partir da segunda semana e piores resultados na fase de engorda. As aves tratadas apresentaram diarreia e comprometimento da integridade intestinal. Em contrapartida, os grupos tratados com a farinha tiveram menor taxa de colonização intestinal por Salmonella Kedougou, após o desafio. Não foram detectadas diferenças estatisticamente significativas nos parâmetros zootécnicos dos frangos que receberam a inulina, e a análise morfométrica não evidenciou lesões nas vilosidades intestinais. No entanto, não houve proteção no desafio por Salmonella Enteritidis, independentemente da associação com probiótico. Esses resultados demonstraram que o modo de administração tem influência sobre o efeito prebiótico da bardana. A farinha de bardana foi administrada por 42 dias, o que pode ter causado a lesão da mucosa intestinal. Em contrapartida, a inulina foi administrada apenas nos primeiros três primeiros dias, o que pode ter sido insuficiente para proteção contra Salmonella. Novos experimentos são necessários para determinar uma formulação capaz de promover efeito protetor, sem impacto negativo no crescimento, ganho de peso e conversão alimentar dos animais suplementados.(AU)

Low temperatures reduce skin healing in the Jacaré do Pantanal (Caiman yacare, Daudin 1802).

Studies of skin wound healing in crocodilians are necessary given the frequent occurrence of cannibalism in intensive farming systems. Air temperature affects tissue recovery because crocodilians are ectothermic. Therefore, the kinetics of skin wound healing in Caiman yacare were examined at temperatures of 33°C and 23°C. Sixteen caiman were selected and divided into two groups of eight maintained at 23°C or 33°C. The studied individuals' scars were photographed after 1, 2, 3, 7, 15 and 30 days of the experimental conditions, and samples were collected for histological processing after 3, 7, 15 and 30 days. Macroscopically, the blood clot (heterophilic granuloma) noticeably remained in place covering the wound longer for the caiman kept at 23°C. Microscopically, the temperature of 23°C slowed epidermal migration and skin repair. Comparatively, new blood vessels, labeled using von Willebrand factor (vWF) antibody staining, were more frequently found in the scars of the 33°C group. The collagen fibers in the dermis were denser in the 33°C treatment. Considering the delayed healing at 23°C, producers are recommended to keep wounded animals at 33°C, especially when tanks are cold, to enable rapid wound closure and better repair of collagen fibers because such lesions tend to compromise the use of their skin as leather.

Rho signaling pathway and apical constriction in the early lens placode.

Epithelial invagination in many model systems is driven by apical cell constriction, mediated by actin and myosin II contraction regulated by GTPase activity. Here we investigate apical constriction during chick lens placode invagination. Inhibition of actin polymerization and myosin II activity by cytochalasin D or blebbistatin prevents lens invagination. To further verify if lens placode invaginate through apical constriction, we analyzed the role of Rho-ROCK pathway. Rho GTPases expression at the apical portion of the lens placode occurs with the same dynamics as that of the cytoskeleton. Overexpression of the pan-Rho inhibitor C3 exotoxin abolished invagination and had a strong effect on apical myosin II enrichment and a mild effect on apical actin localization. In contrast, pharmacological inhibition of ROCK activity interfered significantly with apical enrichment of both actin and myosin. These results suggest that apical constriction in lens invagination involves ROCK but apical concentration of actin and myosin are regulated through different pathways upstream of ROCK. genesis 49:368-379, 2011.