An acetic acid-based extraction method to obtain high quality collagen from archeological bone remains

Human bones, recovered from excavations, are an important biological archive of information. In particular, the analysis of the collagen fraction is useful for paleodietary reconstruction, via light stable isotopes, and for 14C dating. Generally, collagen extraction procedures do not prevent loss of integrity of proteins. As a consequence, information about the state-of-remains preservation is unavailable. Here we describe a ‘‘soft’’ nondestructive CH3COOH-based method to recover collagen from archaeological bones, and also to obtain material for successive isotopic analyses. Our isotopic measurements on the extracts indicate that the CH3COOH-based method of extraction may be routinely employed in the context of paleodiet studies. In addition, we propose that biochemical characterization by denaturant electrophoresis and Western blot on CH3COOH extracts may be used as a bone collagen quality indicator

Determination of 13C/12C Carbon Isotope Ratio

Isotopomers 12CO2 and 13CO2 absorbed into polystyrene films provide narrow, sharp, and well-resolved IR absorption bands for the î3 antisymmetric stretching mode. This is exploited to set up an inexpensive FT-IR-based method for the measurement of the carbon isotope ratio. Accuracy of 2.5‰ ä13C units is readily achieved already at a low resolution of 2 cm-1

Comunidades de macroalgas en puntas rocosas de la costa de Rocha, Uruguay

Macroalgal communities are fundamental for marine ecosystems and very sensitive to environmental changes (e.g temperature, salinity). The Uruguayan Atlantic coast represents a transition between subtropical and subantarctic phycoflora and therefore has a key role to the regional biogeography of macroalgae. The objective of this study was to analyze the macroalgal community richness and biomass, its spatial distribution and its changes along diverse environmental gradients in rocky outcrops of Rocha coast (33°S; 54°W), Uruguay. Two samplings were carried out (summer and winter) in rocky shores of Cerro Verde (La Coronilla), Cerro Rivero (Punta del Diablo) and El Cabito (La Paloma). Transects were used to cover different microhabitats and depths, environmental variables were measured and samples collected. A total of 36 taxa were identified (21 Rhodophyta, 11 Chlorophyta and 4 Ochrophyta). The species richness and biomass were higher in summer for every site, with communities dominated by subtropical species. Temperature was a key modulating factor. For all the species, 50 % were previously registered in previous literature for Uruguay and Ulva spp. complex (Chlorophyta) was the most frequent. Ochrophyta were less frequent being associated with cold and clear waters. Present results provide a basis for the macroalgae management of the Uruguayan coast, reopening a line for future research in the subject.Las macroalgas son fundamentales para los ecosistemas marinos y son muy sensibles a los cambios ambientales (por ejemplo, temperatura, salinidad). La costa atlántica uruguaya es clave para la biogeografía regional de macroalgas, transición entre la ficoflora subtropical y subantártica. El objetivo de este trabajo fue evaluar la riqueza de especies y biomasa de macroalgas, su distribución espacial y relación con variables ambientales en puntas rocosas de la costa de Rocha (33°S; 54°O), Uruguay. Se realizaron dos muestreos (verano e invierno) en puntas rocosas de Cerro Verde (La Coronilla), Cerro Rivero (Punta del Diablo) y El Cabito (La Paloma). Mediante transectas se cubrieron distintas profundidades, midieron variables ambientales y colectaron muestras. Se identificaron en total 36 taxa (21 rodofitas, 11 clorofitas y 4 ocrofitas). La riqueza de especies y biomasa fue mayor en verano para todos los sitios con especies principalmente subtropicales, y la temperatura fue un factor clave. Las ocrofitas ocurrieron en menor frecuencia, asociadas a aguas frías y claras. Se alcanzó el 50 % del total de especies registradas para Uruguay; el complejo Ulva spp. (clorofita) fue el más frecuente. El conocimiento generado aportará al manejo de las macroalgas uruguayas retomando la línea de investigación y favoreciendo el desarrollo de trabajos futuros en el tema

Comunidades de macroalgas en puntas rocosas de la costa de Rocha, Uruguay = Macroalgae communities in rocky outcrops in Rocha, Uruguay

Las macroalgas son fundamentales para los ecosistemas marinos y son muy sensibles a los cambios ambientales (por ejemplo, temperatura, salinidad). La costa atlántica uruguaya es clave para la biogeografía regional de macroalgas, transición entre la ficoflora subtropical y subantártica. El objetivo de este trabajo fue evaluar la riqueza de especies y biomasa de macroalgas, su distribución espacial y relación con variables ambientales en puntas rocosas de la costa de Rocha (33°S; 54°O), Uruguay. Se realizaron dos muestreos (verano e invierno) en puntas rocosas de Cerro Verde (La Coronilla), Cerro Rivero (Punta del Diablo) y El Cabito (La Paloma). Mediante transectas se cubrieron distintas profundidades, midieron variables ambientales y colectaron muestras. Se identificaron en total 36 taxa (21 rodofitas, 11 clorofitas y 4 ocrofitas). La riqueza de especies y biomasa fue mayor en verano para todos los sitios con especies principalmente subtropicales, y la temperatura fue un factor clave. Las ocrofitas ocurrieron en menor frecuencia, asociadas a aguas frías y claras. Se alcanzó el 50 % del total de especies registradas para Uruguay; el complejo Ulva spp. (clorofita) fue el más frecuente. El conocimiento generado aportará al manejo de las macro-algas uruguayas retomando la línea de investigación y favoreciendo el desarrollo de trabajos futuros en el tema

The pathogenesis of the white matter abnormalities in phenylketonuria. A multimodal 3.0 tesla MRI and magnetic resonance spectroscopy (1H MRS) study

Objective: To gain insights into the nature and pathogenesis of white matter (WM) abnormalities in PKU. Methods: Thirty-two patients with phenylalanine hydroxylase deficiency (21 with early and 11 with late diagnosis and treatment) and 30 healthy controls underwent an integrated clinical, neuroimaging (3.0 T MRI, diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI)) and neurochemical (1H MRS) investigation. Results: All patients had white matter abnormalities on T2-weighted (T2W) and fluid-attenuated inversion recovery (FLAIR) scans; parietal white was consistently affected, followed by occipital, frontal and temporal white matter. T1-weighted hypointense alterations were also found in 8 of 32 patients. DWI hyperintense areas overlapped with those detected on T2W/FLAIR. The apparent diffusion coefficient (ADC) was reduced and correlated inversely with severity of white matter involvement. Fractional anisotropy index, eigenvalues λmin, λmiddle, λmax obtained from DTI data, and the principal brain metabolites assessed by 1H MRS (except brain phenylalanine (Phe)) were normal. Brain Phe peak was detected in all but two subjects. Brain and blood Phe were strictly associated. Blood Phe at the diagnosis, patient's age, and concurrent brain Phe independently influence white matter alteration (as expressed by conventional MRI or ADC values). Conclusions: (a) MRI abnormalities in phenylketonuria are the result of a distinctive alteration of white matter suggesting the intracellular accumulation of a hydrophilic metabolite, which leaves unaffected white matter architecture and structure. (b) White matter abnormalities do not seem to reflect the mechanisms involved in the derangement of mental development in PKU. (c) Our data do not support the usefulness of conventional brain MRI examination in the clinical monitoring of phenylketonuria patients. © SSIEM and Springer 2007