The mechanically adaptive connective tissue of echinoderms: its potential for bio-innovation in applied technology and ecology

Echinoderms possess unique connective tissues, called mutable collagenous tissues (MCTs), which undergo nervously mediated, drastic and reversible or irreversible changes in their mechanical properties. Connective tissue mutability influences all aspects of echinoderm biology and is a key-factor in the ecological success of the phylum. Due to their sensitivity to endogenous or exogenous agents, MCTs may be targets for a number of common pollutants, with potentially drastic effects on vital functions. Besides its ecological relevance, MCT represents a topic with relevance to several applied fields. A promising research route looks at MCTs as a source of inspiration for the development of novel biomaterials. This contribution presents a review of MCT biology, which incorporates recent ultrastructural, biomolecular and biochemical analyses carried out in a biotechnological context.

Crop row detection in maize fields inspired on the human visual perception

This paper proposes a new method, oriented to image real-time processing, for identifying crop rows in maize fields in the images. The vision system is designed to be installed onboard a mobile agricultural vehicle, that is, submitted to gyros, vibrations, and undesired movements. The images are captured under image perspective, being affected by the above undesired effects. The image processing consists of two main processes: image segmentation and crop row detection. The first one applies a threshold to separate green plants or pixels (crops and weeds) from the rest (soil, stones, and others). It is based on a fuzzy clustering process, which allows obtaining the threshold to be applied during the normal operation process. The crop row detection applies a method based on image perspective projection that searches for maximum accumulation of segmented green pixels along straight alignments. They determine the expected crop lines in the images. The method is robust enough to work under the above-mentioned undesired effects. It is favorably compared against the well-tested Hough transformation for line detection.

Acute heat stress impairs performance parameters and induces mild intestinal enteritis in broiler chickens: role of acute hypothalamic-pituitary-adrenal axis activation

Studies on the environmental consequences of stress are relevant for economic and animal welfare reasons. We recently reported that long-term heat stressors (31 ± 1°C and 36 ± 1°C for 10 h/d) applied to broiler chickens (Gallus gallus domesticus) from d 35 to 42 of life increased serum corticosterone concentrations, decreased performance variables and the macrophage oxidative burst, and produced mild, multifocal acute enteritis. Being cognizant of the relevance of acute heat stress on tropical and subtropical poultry production, we designed the current experiment to analyze, from a neuroimmune perspective, the effects of an acute heat stress (31 ± 1°C for 10 h on d 35 of life) on serum corticosterone, performance variables, intestinal histology, and peritoneal macrophage activity in chickens. We demonstrated that the acute heat stress increased serum corticosterone concentrations and mortality and decreased food intake, BW gain, and feed conversion (P < 0.05). We did not find changes in the relative weights of the spleen, thymus, and bursa of Fabricius (P > 0.05). Increases in the basal and the Staphylococcus aureus-induced macrophage oxidative bursts and a decrease in the percentage of macrophages performing phagocytosis were also observed. Finally, mild, multifocal acute enteritis, characterized by the increased presence of lymphocytes and plasmocytes within the lamina propria of the jejunum, was also observed. We found that the stress-induced hypothalamic-pituitary-adrenal axis activation was responsible for the negative effects observed on chicken performance and immune function as well as for the changes in the intestinal mucosa. The data presented here corroborate with those presented in other studies in the field of neuroimmunomodulation and open new avenues for the improvement of broiler chicken welfare and production performance.

A comparative study between fluoroscopic and endoscopic guidance in palliative esophageal stent placement

Self-expanding metallic stents (SEMS) are the treatment of choice for incurable obstructive malignant esophageal strictures. Although the placement of SEMS is usually performed with fluoroscopic control (FC), recently several authors have shown the feasibility of placing SEMS under endoscopic control alone (EC). However, studies comparing the two techniques are lacking. The objective of this study was to compare the feasibility and safety of SEMS insertion under fluoroscopic control and endoscopic control. The study was performed through the retrospective analysis of patients who underwent SEMS insertion for malignant dysphagia between January 2005 and January 2010. Data concerning early and late complications and survival were retrieved. Early complications were defined as pain, vomiting, bleeding, malposition/migration, perforation, and/or dysphagia occurring until 30 days of SEMS insertion; and late complications as tumor ingrowth and overgrowth, migration, hemorrhage, fistulae, food impaction, and/or esophagitis occurring after 30 days. We placed 126 SEMS of which 87% for esophageal stricture, 8% for esophagus-respiratory fistula, and 5% for extrinsic compression. The mean age of the patients was 62 years, and 93 were male. SEMS insertion was performed with FC in 66 patients and EC in 60. Early complications occurred in 34 patients (52%) in the FC group and 28 (47%) in the EC group (P=0.71), including: pain in 22 patients of the FC group and 15 of the EC group (P=0.31); vomiting in 15 of the FC group and nine of the EC group (P=0.27); malposition/migration in three of the FC group and four of the EC group (P=0.60); hemorrhage in one of the FC group and two of the EC group (P=0.27); and dysphagia in two of the FC group and three of the EC group (P=0.57). Late complications occurred in 20 patients (30%) in the FC group and 22 (37%) in the EC group (P=0.44), including: tumor in/overgrowth in 13 patients of the FC group and 10 of the EC group (P=0.66); prostheses migration in five of the FC group and eight of the EC group (P=0.28); hemorrhage in two of the FC group and two of the EC group (P=0.54); appearance of esophageal fistulae in seven of the FC group and four of the EC group (P=0.43); food impaction in nine of the FC group and eight of the EC group (P=0.96); esophagitis in 12 of the FC group and 15 of the EC group (P=0.35). Median survival was 107 days (95% confidence interval [CI]=6-369 days) with no difference between the two groups. There were no statistical significant differences in the incidence of complications and in survival between patients undergoing SEMS placement under fluoroscopic control or endoscopic control.

Relationships among estrogen receptor, oxytocin and vasopressin gene expression and social interaction in male mice

The incidence of social disorders such as autism and schizophrenia is significantly higher in males, and the presentation more severe, than in females. This suggests the possible contribution of sex hormones to the development of these psychiatric disorders. There is also evidence that these disorders are highly heritable. To contribute toward our understanding of the mechanisms underlying social behaviors, particularly social interaction, we assessed the relationship of social interaction with gene expression for two neuropeptides, oxytocin (OT) and arginine vasopressin (AVP), using adult male mice. Social interaction was positively correlated with: oxytocin receptor (OTR) and vasopressin receptor (V1aR) mRNA expression in the medial amygdala; and OT and AVP mRNA expression in the paraventricular nucleus of the hypothalamus (PVN). When mice representing extremes of social interaction were compared, all of these mRNAs were more highly expressed in high social interaction mice than in low social interaction mice. OTR and V1aR mRNAs were highly correlated with estrogen receptor α (ERα) mRNA in the medial amygdala, and OT and AVP mRNAs with estrogen receptor β (ERβ) mRNA in the PVN, indicating that OT and AVP systems are tightly regulated by estrogen receptors. A significant difference in the level of ERα mRNA in the medial amygdala between high and low social interaction mice was also observed. These results support the hypothesis that variations of estrogen receptor levels are associated with differences in social interaction through the OT and AVP systems, by upregulating gene expression for those peptides and their receptors.

Differential behavioral outcomes of 3,4-methylenedioxymethamphetamine (MDMA-ecstasy) in anxiety-like responses in mice

Anxiolytic and anxiogenic-like behavioral outcomes have been reported for methylenedioxymethamphetamine (MDMA or ecstasy) in rodents. In the present experiment, we attempted to identify behavioral, hormonal and neurochemical outcomes of MDMA treatment to clarify its effects on anxiety-related responses in 2-month-old Balb/c male mice (25-35 g; N = 7-10 mice/group). The behavioral tests used were open field, elevated plus maze, hole board, and defensive behavior against predator odor. Moreover, we also determined striatal dopamine and dopamine turnover, and serum corticosterone levels. MDMA was injected ip at 0.2, 1.0, 5.0, 8.0, 10, or 20 mg/kg. MDMA at 10 mg/kg induced the following significant (P < 0.05) effects: a) a dose-dependent increase in the distance traveled and in the time spent moving in the open field; b) decreased exploratory activity in the hole board as measured by number of head dips and time spent in head dipping; c) increased number of open arm entries and increased time spent in open arm exploration in the elevated plus maze; d) increased time spent away from an aversive stimulus and decreased number of risk assessments in an aversive odor chamber; e) increased serum corticosterone levels, and f) increased striatal dopamine level and turnover. Taken together, these data suggest an anxiogenic-like effect of acute MDMA treatment, despite the fact that behavioral anxiety expression was impaired in some of the behavioral tests used as a consequence of the motor stimulating effects of MDMA.

rEnolase maternal immunization confers caries protection on offspring

Therapeutic vaccination with Streptococcus sobrinus recombinant enolase (rEnolase) protects rats from dental caries. Here, we investigated the effect that maternal rEnolase vaccination before pregnancy had on the offspring's immune response to S. sobrinus oral infection and dental caries progression. Female Wistar rats were immunized by intranasal and subcutaneous routes with rEnolase adsorbed onto aluminum hydroxide as adjuvant or similarly treated with the adjuvant alone (sham-immunized). Ten days after the last administration, the immunized females were paired with a male rat. The oral immune responses to S. sobrinus infection and dental caries in the offspring were evaluated. The results showed that pups born from rEnolase-immunized mothers had higher levels of rEnolase-specific salivary IgA and IgG antibodies (indicating a placental antibody transfer) and lower sulcal and proximal enamel caries scores than rats born from sham-immunized mothers. In conclusion, rEnolase maternal immunization before pregnancy provides offspring with protection against S. sobrinus-induced dental caries.

Population structure and genetic diversity of wild Helianthus species from Mozambique

The production of sunflower suffered a major decline in Mozambique after its independence in 1975. Civil war, human activities and environmental damage subjected the species to an ecological stress contributing to reduce the number and size of wild populations. As this reduction is often related to a loss of genetic variation we estimated the genetic diversity within and among populations of wild Helianthus from five districts of Mozambique using RAPD markers. The 44 accessions studied grouped into four major clusters exhibiting structured variability with regard to geographic origin. A high level of genetic diversity (He = 0.350 and I = 0.527) was retained at the population level. The genetic variation among populations was high (59.7%), which is consistent with low gene flow (Nm = 0.338). The proportion of total genetic diversity residing among these populations should be kept in mind to devise different conservation strategies in order to preserve these populations. Currently wild Helianthus genetic resources present in Maputo and Sofala are on the edge of extinction mainly due to excessive urbanization. Therefore, conservation of what remains of this plant genetic diversity is essential for sustainable utilization and can be useful for breeding programs.

Structure of the Channels in the Outer Mitochondrial Membrane: Electron Microscopic Studies of the Periodic Arrays Induced by Phospholipase a(2) Treatment of the Neurospora membrane

The channel proteins in outer membranes of Neurospora crassa mitochondria spontaneously organize into periodic arrays when the membranes are dialyzed in the presence of soluble phospholipase A(2). Electron microscopic images have been recorded at different electron doses from channel arrays in a variety of negative stains, as well as in vitreous ice. Fourier or correlation averages are formed from image fields containing a few hundred unit cells. These averages can be subsequently classified by correspondence analysis and summed to form representative averages over thousands of unit cells. In averages of negatively stained arrays, the stain-filled channel openings are bounded by smaller stain-excluding maxima. The projections of the channel openings are smaller and the subsidiary maxima are more pronounced for channel arrays contrasted with dilute (0.1%) uranyl acetate or aurothioglucose than for arrays embedded in 1% uranyl acetate. Projection images of unstained, ice-embedded membranes provide direct information about distribution of protein and lipid in the VDAC arrays. First experiments have yielded density maps with an apparent Fourier resolution of approximately 1/(2 nm).