Epibionts on Turbinaria ornata, a secondary foundational macroalga on coral reefs, provide diverse trophic support to fishes.

Worldwide, many coral reef ecosystems have shifted from coral to algal dominance, yet the ecological function of these emergent communities remains relatively unknown. Turbinaria ornata, a macroalga with a rapidly expanding range in the South Pacific, forms dense stands on hard substrate, likely providing ecological services unique from corals. While generally unpalatable, T. ornata can function as a secondary foundation species and hosts an epibiont community that may provide overlooked trophic resources in phase shifted reef ecosystems. Results from video recorded field experiments designed to quantify consumer pressure on T. ornata epibionts showed that both consumer pressure and epibiont cover increased with thallus size. Additionally, most fish species, including herbivores, omnivores, and detritivores, exhibited higher bite rates on thalli with epibionts compared to thali with epibionts experimentally removed. Juvenile parrotfishes were responsible for 50% of total bites recorded and also had the highest bite rates. Results indicate that epibionts, particularly on large T. ornata, are a food resource for a diversity of fishes, representing a previously undescribed function of this macroalga in coral reef ecosystems. Exploring the functions of macroalgal dominated reef communities will be increasingly important as reefs continue to phase shift toward macroalgal dominance in the Anthropocene.

Solvent-dependent inversion of circular dichroism signal in naproxen: An unusual effect!

The electronic circular dichroism (ECD) spectra of naproxen enantiomers were studied as a function of solvents using experimental (circular dichroism) and theoretical (time-dependent density functional theory) approaches. The (R)- and (S)-naproxen enantiomers presented an unusual inversion in their ECD signals in the presence of ethanol and water when compared with polar aprotic solvents such as acetonitrile. From a practical point of view, these findings deserve great attention because these solvents are widely used for high-performance liquid chromatography analysis in quality control of chiral pharmaceutical drugs. This is particularly relevant to naproxen because the (S)-naproxen has anti-inflammatory properties, whereas (R)-naproxen is hepatotoxic. A time-dependent density functional theory computer simulation was conducted to investigate the signal inversion using the solvation model based on density, a reparameterization of polarized continuum model. Electronic circular dichroism signals of conformers were calculated by computer simulation and their contribution to the combined spectra obtained according to Boltzmann weighting. It was found that the experimentally observed ECD signal inversion can be associated with the minor or major contribution of different conformers of naproxen.

Genome-wide association across Saccharomyces cerevisiae strains reveals substantial variation in underlying gene requirements for toxin tolerance.

Cellulosic plant biomass is a promising sustainable resource for generating alternative biofuels and biochemicals with microbial factories. But a remaining bottleneck is engineering microbes that are tolerant of toxins generated during biomass processing, because mechanisms of toxin defense are only beginning to emerge. Here, we exploited natural diversity in 165 Saccharomyces cerevisiae strains isolated from diverse geographical and ecological niches, to identify mechanisms of hydrolysate-toxin tolerance. We performed genome-wide association (GWA) analysis to identify genetic variants underlying toxin tolerance, and gene knockouts and allele-swap experiments to validate the involvement of implicated genes. In the process of this work, we uncovered a surprising difference in genetic architecture depending on strain background: in all but one case, knockout of implicated genes had a significant effect on toxin tolerance in one strain, but no significant effect in another strain. In fact, whether or not the gene was involved in tolerance in each strain background had a bigger contribution to strain-specific variation than allelic differences. Our results suggest a major difference in the underlying network of causal genes in different strains, suggesting that mechanisms of hydrolysate tolerance are very dependent on the genetic background. These results could have significant implications for interpreting GWA results and raise important considerations for engineering strategies for industrial strain improvement.

Ruptured true superficial femoral artery aneurysm / Aneurisma verdadeiro roto de arteria femoral superficial

Femoral artery aneurysms are rare and generally affect elderly patients. They are often diagnosed in combination with aneurysms in other locations, such as peripheral and aortic aneurysms. This case report describes a young patient whose superficial femoral artery (SFA) had a clinical presentation suggestive of a ruptured aneurysm. The patient underwent standard treatment, with aneurysmectomy and interposition of the ipsilateral saphenous vein. A review of the literature confirms the rarity of this case.

Os aneurismas de artéria femoral são raros e ocorrem geralmente em pacientes idosos. Estão frequentemente associados a outros aneurismas, tanto periféricos como de aorta abdominal. O presente relato refere-se a um jovem portador de aneurisma de artéria femoral superficial (AFS), cuja apresentação clínica foi a ruptura. O paciente foi submetido ao tratamento convencional, com ressecção do aneurisma e interposição de veia safena magna ipsilateral. A revisão da literatura corrobora a raridade do caso.

Condyle-disk-fossa position and relationship to clinical signs and symptoms of temporomandibular disorders in women.

OBJECTIVE: The aim of the present study was to assess the disk-condyle-fossa relationship through magnetic resonance imaging and determine its association with clinical signs and symptoms of temporomandibular disorder in patients with myofascial pain and disk displacement (with and without reduction). STUDY DESIGN: Sixty-two female patients with complaints of pain were clinically examined using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and divided into the following groups: Group I, myofascial pain (n = 19); Group IIa, disk displacement with reduction (n = 32); and Groups IIb and IIc, disk displacement without reduction (n = 11). Classification of disk position was based on the positioning on a clock face (> or < than 11 o'clock) and condylar excursion was determined as (1) the proximal side of the apex of the articular eminence; (2) at the level of the articular eminence; and (3) beyond the apex of the articular eminence. Condylar position was determined in the sagittal images based on Gelb's template (normal, posteriorly displaced). Pain was assessed using a visual analogue scale (VAS). The univariate logistic regression, Mann-Whitney, Kruskall-Wallis and Pearson's correlation tests were used in the statistical analysis (P < or = .05). RESULTS: No significant association was found between the independent variables (condylar position, disk position, and condylar excursion) and the dependent variables (pain, maximal opening of the mouth, maximal lateral movement). However, there was a significant association between increased condyle excursion and pain (P = .035) and also maximum mouth opening movement was associated with lateral movement (P = .01; r = 0.31). CONCLUSIONS: Increase in condyle excursion may significantly influence pain perception in TMD patients. The type of dysfunction and severity of alterations on the imaging exams were not related to the severity of pain or range of motion of the mandible.

Do peroxisome proliferating compounds pose a hepatocarcinogenic hazard to humans?

The purpose of the workshop "Do Peroxisome Proliferating Compounds Pose a Hepatocarcinogenic Hazard to Humans?" was to provide a review of the current state of the science on the relationship between peroxisome proliferation and hepatocarcinogenesis. There has been much debate regarding the mechanism by which peroxisome proliferators may induce liver tumors in rats and mice and whether these events occur in humans. A primary goal of the workshop was to determine where consensus might be reached regarding the interpretation of these data relative to the assessment of potential human risks. A core set of biochemical and cellular events has been identified in the rodent strains that are susceptible to the hepatocarcinogenic effects of peroxisome proliferators, including peroxisome proliferation, increases in fatty acyl-CoA oxidase levels, microsomal fatty acid oxidation, excess production of hydrogen peroxide, increases in rates of cell proliferation, and expression and activation of the alpha subtype of the peroxisome proliferator-activated receptor (PPAR-alpha). Such effects have not been identified clinically in liver biopsies from humans exposed to peroxisome proliferators or in in vitro studies with human hepatocytes, although PPAR-alpha is expressed at a very low level in human liver. Consensus was reached regarding the significant intermediary roles of cell proliferation and PPAR-alpha receptor expression and activation in tumor formation. Information considered necessary for characterizing a compound as a peroxisome proliferating hepatocarcinogen include hepatomegaly, enhanced cell proliferation, and an increase in hepatic acyl-CoA oxidase and/or palmitoyl-CoA oxidation levels. Given the lack of genotoxic potential of most peroxisome proliferating agents, and since humans appear likely to be refractive or insensitive to the tumorigenic response, risk assessments based on tumor data may not be appropriate. However, nontumor data on intermediate endpoints would provide appropriate toxicological endpoints to determine a point of departure such as the LED10 or NOAEL which would be the basis for a margin-of-exposure (MOE) risk assessment approach. Pertinent factors to be considered in the MOE evaluation would include the slope of the dose-response curve at the point of departure, the background exposure levels, and variability in the human response. Copyright 1998 Academic Press.