Fluorescent N-arylaminonaphthalene sulfonate probes for amyloid aggregation of alpha-synuclein

The deposition of fibrillar structures (amyloids) is characteristic of pathological conditions including Alzheimer's and Parkinson's diseases. The detection of protein deposits and the evaluation of their kinetics of aggregation are generally based on fluorescent probes such as thioflavin T and Congo red. In a search for improved fluorescence tools for studying amyloid formation, we explored the ability of N-arylaminonaphthalene sulfonate (NAS) derivatives to act as noncovalent probes of α-synuclein (AS) fibrillation, a process linked to Parkinson's disease and other neurodegenerative disorders. The compounds bound to fibrillar AS with micromolar K_ds, and exhibited fluorescence enhancement, hyperchromism, and high anisotropy. We conclude that the probes experience a hydrophobic environment and/or restricted motion in a polar region. Time- and spectrally resolved emission intensity and anisotropy provided further information regarding structural features of the protein and the dynamics of solvent relaxation. The steady-state and time-resolved parameters changed during the course of aggregation. Compared with thioflavin T, NAS derivatives constitute more sensitive and versatile probes for AS aggregation, and in the case of bis-NAS detect oligomeric as well as fibrillar species. They can function in convenient, continuous assays, thereby providing useful tools for studying the mechanisms of amyloid formation and for high-throughput screening of factors inhibiting and/or reversing protein aggregation in neurodegenerative diseases.     

The intramolecular autoglucosylation of monomeric glycogenin

The ability of monomeric glycogenin to autoglucosylate by an intramolecular mechanism of reaction is described using non-glucosylated and partially glucosylated recombinant glycogenin. We determined that monomer glycogenin exists in solution at concentration below 0.60-0.85 μM. The specific autoglucosylation rate of non-glucosylated and glucosylated monomeric glycogenin represented 50 and 70% of the specific rate of the corresponding dimeric glycogenin species. The incorporation of a unique sugar unit into the tyrosine hydroxyl group of non-glucosylated glycogenin, analyzed by autoxylosylation, occurred at a lower rate than the incorporation into the glucose hydroxyl group of the glucosylated enzyme. The intramonomer autoglucosylation mechanism here described for the first time, confers to a just synthesized glycogenin molecule the capacity to produce maltosaccharide primer for glycogen synthase, without the need to reach the concentration required for association into the more efficient autoglucosylating dimer. The monomeric and dimeric interconversion determining the different autoglucosylation rate, might serve as a modulation mechanism for the de novo biosynthesis of glycogen at the initial glucose polymerization step.     

Genital microsporidiosis in women with AIDS: A post-mortem study

BackgroundMicrosporidiosis is a life threatening opportunistic infection of AIDS patients. The infection is usually restricted to specific anatomical areas, but could become systemic depending on the involved species. Genital microsporidiosis in female patients is rare.ObjectiveTo report genital microsporidiosis in female AIDS patients.MethodsTissues samples from the genital tract (ovary, fallopian tubes and uterus) of eight deceased women who died of wasting syndrome associated to AIDS and disseminated microsporidiosis at the Institute of Tropical Medicine Pedro Kourí were collected between 1997 and 2005. Using an indirect immunohistochemistry assay the microsporidia species involved in those cases were identified.ResultsWe report several cases of microsporidial infection of the female genital tract. Six out of eight women with the disseminated form of the disease showed the presence of microsporidia in the genital tract. Encephalitozoon cuniculi and Encephalitozoon hellem were identified in the internal lining epithelium of the fallopian tubes and endometrium.ConclusionsMicrosporidia species could disseminate to other organs and become systemic in severe immunocompromised cases. To our knowledge this is the greatest number of female genital tract microsporidiosis cases so far reported in humans.     

Treating patients with fibromyalgia in primary care settings under routine medical practice: a claim database cost and burden of illness study

Introduction  

The objective of this study was to analyze health care and non-health care resource utilization under routine medical practice in a primary care setting claims database and to estimate the incremental average cost per patient per year of fibromyalgia syndrome (FMS) compared with a reference population.     

Distribution and nature of desmosomes in the bovine developing ruminal epithelium.

Desmosomes entirely similar to those of the deeper layers of ruminal epithelium are seen in the luminal layers of the early fetal ruminal epithelium. In the older fetuses, these desmosomes have morphological features that reveal to some extent the occurrence of processes of keratinization. This could indicate that the basis for cell keratinization is already present in the fetus and that postnatal keratinization corresponds mainly to the full development of the prenatally existing pattern of differentiation.     

Particulate organic carbon is a sensitive indicator of soil degradation related to overgrazing in Patagonian wet and mesic meadows

Patagonian meadows are key for the development and sustainability of rural environments. However, they have been degraded due to a combination of weather conditions and overgrazing. Total soil organic carbon (TOC) has been found as a moderate indicator of meadow soil degradation by long-term heavy grazing. The aim of this study was to evaluate the particulate organic carbon (POC) (a more labile fraction of the soil organic matter) as an ecological indicator for assessing soil changes in natural Patagonian meadows, related to different long-term grazing managements. We worked in three locations along a precipitation gradient in Northern Patagonia. Each location has wet and mesic meadows with good and poor grassland condition, attributed to two long-term grazing pressures (light and heavy). We sampled soil throughout the plant-growing season following the natural soil moisture fluctuations, and quantified the POC content, the POC:TOC ratio, and the F_>53 proportion. Along the different sampling dates, significant differences between good versus poor grassland condition were found in many cases in POC, a few in POC:TOC ratio, and none in F_>53 proportion. The POC varies over time, in association with changes in the soil moisture (adjusted R² vary between 0.76 and 0.99); therefore, the sampling date must be standardized (we recommend dry periods). The POC appears to be a sensitive indicator when assessing the effect of different soil management practices on soil quality, an important step for meadow conservation, restoration and sustainable use, but further research is needed to validate this exploratory study.     

Breathing synchrony in franciscana (Pontoporia blainvillei) and Guiana dolphins (Sotalia guianensis) in Southern Brazil

Synchronous breathing may be a useful proxy for studying other, and perhaps more complex, aspects of cetacean behavior. Here we describe a study conducted in Babitonga Bay, southern Brazil, where we investigated the synchrony of breathing in two small populations of franciscana (Pontoporia blainvillei) and Guiana dolphins (Sotalia guianensis). The bay is affected by different sources of anthropogenic disturbances, such as boat activity and point‐source pollution. We assumed breathing synchrony to be the inverse of the time between breathing surfacing displays of dolphins within a swimming pair, which we refer to as lag. The relationship between lag and anthropogenic and animal‐related variables was evaluated with generalized additive models. For franciscana dolphins, breathing synchrony was only positively related to the proximity between animals. Breathing synchrony in Guiana dolphins was positively related to both the proximity between animals and to group size, and varied significantly depending on the research boat used. Proximal characteristics (i.e., of individuals or of the group) of these dolphin species seem to be more related to the synchronization in breathing than are the environmental variables assessed here. Results presented expand the current knowledge of these two dolphin species and provide general insights into the breathing synchrony for cetaceans.