Morphology and immunolocalization of intertubular steroidogenic cell in mesonephros of Podocnemis expansa during gonadal differentiation

Sex steroid hormones are critical in gonadal differentiation in turtles. The gonads are not the only organs responsible for producing these hormones during this phase. Mesonephros play an important role in steroidogenesis. The present study aimed to investigate the presence of steroidogenic cells in mesonephros of Podocnemis expansa during gonadal differentiation and to evaluate their morphology and ultrastructure. Ten embryos of P. expansa were collected from 5 nests on day 36 of incubation, during spawning period on an artificial beach. Embryos were extracted from eggs by slicing the shell and euthanized. They were dissected under a stereoscopic microscope to collect the gonad-mesonephro complex, in which were fixed and subsequently processed for light microscopy, immunohistochemistry and transmission electron microscopy analysis. During histological analysis was observed mesonephros has typical morphological structure. Immunohistochemistry showed immunoreaction to aromatase in cells of intertubular space. Confirming these findings, it was possible to observe a type of intertubular cell in several regions of mesonephro, being more predominant in region close to blood vessels, distal and proximal tubules. In ultrastructural analysis these cells were characterized by having a clear, large, and rounded nucleus with evident nucleolus and cytoplasm rich in electron-dense droplets. This study demonstrated for the first time the presence of cells with morphological, immunohistochemical and ultrastructural characteristics similar to steroid-producing cells in P. expansa mesonephrons, suggesting that this organ may contribute to gonadal differentiation in this species.     

Diet crude protein reduction on follicular fluid and cumulus-oocyte complexes of mid-lactating Girolando cows

This study evaluated the effect of crude protein (CP) reduction in four diets (156, 139, 132, and 127 g Kg^-1 DM) maintaining constant metabolizable protein (188 g/day) on the follicular fluid and cumulus-oocyte complexes of mid-lactating Girolando cows. Twenty-two Girolando cows with average of 21.55 ±3.19 L daily milk yield, 105.30 ±22.62 days in lactation and 3.22 ±0.03 body condition score were selected. To reduce CP in diets and maintain constant metabolizable protein, urea and soybean meal were gradually replaced by lignosulfonate-treated soybean meal (SoyPass^®, Cargill), resulting in an increase in rumen-undegradable protein and a reduction in rumen degradable protein. A linear and quadratic reduction was observed in the plasma and follicular fluid urea nitrogen concentration following CP reduction, with the most intense reduction occurring in the 127 g Kg^-1 DM group (p<0.001). As CP reduced, there was a tendency for a linear increase in the follicular growth rate (P=0.0696), on the number and proportion of viable oocytes (P<0.09), and also a linear increase for the number (P=0.0397) and proportion (P<0.09) of grade I viable oocytes. Plus, there was a linear effect for the number of cumulus oophorus cells. Cows fed with the lowest amount of CP had cumulus-oocyte complexes with higher numbers of cumulus oophorus cells (P=0.0238). Also, the reduction of diet crude protein was followed by a decrease in the probability of oocytes’ DNA degradation. In conclusion, the reduction of CP in the diet of mid-lactating Girolando cows, reduces urea nitrogen concentration in both blood plasma and follicular fluid, and, as a consequence, increases the viability of oocytes and the number of cumulus oophorus cells while reducing oocytes’ DNA degradation of follicular included cumulus-oocyte complex. The reduction on dietary CP may improve in vivo oocytes’ embryo development impacting fertility of lactating dairy cows.     

Control of Chagas disease in Brazil

Chagas disease (South American trypanosomiasis) is a chronic but often fatal disease endemic throughout much of Latin America. Serological surveys suggest around 24 million people seropositive for the causative agent, Trypanosoma cruzi (Fig. 1), with over 65 million living in the endemic areas and at risk to infection. In Brazil, over 25 million people are considered at risk, and control of the disease constitutes one of Brazil's public health priorities. Treatment or vaccination against T. cruzi is impossible at the public health level because suitable drugs or vaccines are not available. But it is well recognized that transmission can be interrupted by eliminating the domestic vectors - blood-sucking reduviid bugs of the subfamily Triatominae. In Brazil, eradication of Triatoma infestans - the major domestic vector of T. cruzi - is now seen as a feasible target by the Ministry of Health. However, although other domestic vectors can also be controlled, they will retain their sylvatic ecotopes from which they can reinvade houses. In this article, Joao Carlos Pinto Dias explains the current Brazilian policy, high-lighting the successful elimination of T. infestans from much of the southern part of the country.     

Yeast water channels: an overview of orthodox aquaporins

In yeast, the presence of orthodox aquaporins has been first recognized in Saccharomyces cerevisiae, in which two genes (AQY1 and AQY2) were shown to be related to mammal and plant water channels. The present review summarizes the putative orthodox aquaporin protein sequences found in available genomes of yeast and filamentous fungi. Among the 28 yeast genomes sequenced, most species present only one orthodox aquaporin, and no aquaporins were found in eight yeast species. Alignment of amino acid sequences reveals a very diverse group. Similarity values vary from 99% among species within the Saccharomyces genus to 34% between ScAqy1 and the aquaporin from Debaryomyces hansenii. All of the fungal aquaporins possess the known characteristic sequences, and residues involved in the water channel pore are highly conserved. Advances in the establishment of the structure are reviewed in relation to the mechanisms of selectivity, conductance and gating. In particular, the involvement of the protein cytosolic N‐terminus as a channel blocker preventing water flow is addressed. Methodologies used in the evaluation of aquaporin activity frequently involve the measurement of fast volume changes. Particular attention is paid to data analysis to obtain accurate membrane water permeability parameters. Although the presence of aquaporins clearly enhances membrane water permeability, the relevance of these ubiquitous water channels in yeast performance remains obscure.     

Phytoplankton composition and abundance of a central Amazonian floodplain lake

The phytoplankton community of Lake Camaleão, a smallfloodplainlake influenced by a large whitewater river, the Solimões, was monthlyinvestigated for the composition and abundance of itsphytoplankton. The seasonal influence of the floodregime on biomass, species richness and diversity, andits relation with physical and chemical factors(temperature, pH, dissolved oxygen, electricalconductivity, total seston and inorganic nutrients)was analyzed and subjected to principal componentanalysis. Diversity was variable along the seasonalcycle: relatively high values were observed at the endof the dry season supported by high nutrientconcentrations. The phytoplankton was comprised of 262 taxa,with strong dominanceof euglenoids (81%). The three sample stations did not differamong each other, except in the dry season, due todata cluster in relation to theprincipal axis (1 and 2), explaining 63% of thevariation. Biomass accumulation as a function of lakearea reduction contributed to theseresults, indicating that the phytoplankton dynamicswere hydrology-driven.     

Homogeneous Canine Chest Phantom Construction: A Tool for Image Quality Optimization

Digital radiographic imaging is increasing in veterinary practice. The use of radiation demands responsibility to maintain high image quality. Low doses are necessary because workers are requested to restrain the animal. Optimizing digital systems is necessary to avoid unnecessary exposure, causing the phenomenon known as dose creep. Homogeneous phantoms are widely used to optimize image quality and dose. We developed an automatic computational methodology to classify and quantify tissues (i.e., lung tissue, adipose tissue, muscle tissue, and bone) in canine chest computed tomography exams. The thickness of each tissue was converted to simulator materials (i.e., Lucite, aluminum, and air). Dogs were separated into groups of 20 animals each according to weight. Mean weights were 6.5 ± 2.0 kg, 15.0 ± 5.0 kg, 32.0 ± 5.5 kg, and 50.0 ± 12.0 kg, for the small, medium, large, and giant groups, respectively. The one-way analysis of variance revealed significant differences in all simulator material thicknesses (p < 0.05) quantified between groups. As a result, four phantoms were constructed for dorsoventral and lateral views. In conclusion, the present methodology allows the development of phantoms of the canine chest and possibly other body regions and/or animals. The proposed phantom is a practical tool that may be employed in future work to optimize veterinary X-ray procedures.     

CRISPR/Cas9-mediated efficient targeted mutagenesis has the potential to accelerate the domestication of <Emphasis Type="Italic">Coffea canephora</Emphasis>

Genome editing, which is an unprecedented technological breakthrough, has provided a valuable means of creating targeted mutations in plant genomes. In this study, we developed a genomic web tool to identify all gRNA target sequences in the coffee genome, along with potential off-targets. In all, 8,145,748 CRISPR guides were identified in the draft genome of Coffea canephora corresponding to 5,338,568 different sequences and, of these, 4,655,458 were single, and 514,591 were covering exons. The proof of concept was established by targeting the phytoene desaturase gene (CcPDS) using the Agrobacterium tumefaciens transformation technique and somatic embryogenesis as the plant regeneration method. An analysis of the RNA-guided genome-editing events showed that 22.8% of the regenerated plants were heterozygous mutants and 7.6% were homozygous mutants. Mutation efficiency at the target site was estimated to be 30.4%. We demonstrated that genome editing by the CRISPR/Cas9 method is an efficient and reliable way of knocking out genes of agronomic interest in the coffee tree, opening up the way for coffee molecular breeding. Our results also showed that the use of somatic embryogenesis, as the method for regenerating genome-edited plants, could restrict the choice of targeted genes to those that are not essential to the embryo development and germination steps.     

Evaluating different methods of microarray data normalization

Background  

With the development of DNA hybridization microarray technologies, nowadays it is possible to simultaneously assess the expression levels of thousands to tens of thousands of genes. Quantitative comparison of microarrays uncovers distinct patterns of gene expression, which define different cellular phenotypes or cellular responses to drugs. Due to technical biases, normalization of the intensity levels is a pre-requisite to performing further statistical analyses. Therefore, choosing a suitable approach for normalization can be critical, deserving judicious consideration.