6 research outputs found
Early life of Neanderthals
The early onset of weaning in modern humans has been linked to the high nutritional demand of brain development that is intimately connected with infant physiology and growth rate. In Neanderthals, ontogenetic patterns in early life are still debated, with some studies suggesting an accelerated development and others indicating only subtle differences to modern humans. Here we report the onset of weaning and rates of enamel growth using an unprecedented sample set of three late (~70-50 ka) Neanderthals and one Upper Paleolithic modern human from Northeastern-Italy via spatially-resolved chemical/isotopic analyses and histomorphometry of deciduous teeth. Our results reveal that the modern human nursing strategy, with onset of weaning at 5-6 months, was present among these Neanderthals. This evidence, combined with dental development akin to modern humans, highlights their similar metabolic constraints during early life and excludes late weaning as a factor contributing to Neanderthals' demise
Differential availability/processing of decorin precursor in arterial and venous smooth muscle cells
The existence of specific differentiation markers for arterial smooth muscle (SM) cells is still a matter of debate. A clone named MM1 was isolated from a library of monoclonal antibodies to adult porcine aorta, which in vivo binds to arterial but not venous SM cells, except for the pulmonary vein. MM1 immunoreactivity in Western blotting involved bands in the range of Mr 33–226 kDa, in both arterial and venous SM tissues. However, immunoprecipitation experiments revealed that MM1 bound to a 100-kDa polypeptide that was present only in the arterial SM extract. By mass spectrometry analysis of tryptic digests from MM1-positive 130- and 120-kDa polypeptides of aorta SM extract, the antigen recognized by the antibody was identified as a decorin precursor. Using a crude decorin preparation from this tissue MM1 reacted strongly with the 33-kDa polypeptide and this pattern did not change after chondroitinase ABC treatment. In vitro, decorin immunoreactivity was found in secreted grainy material produced by confluent arterial SM cells, although lesser amounts were also seen in venous SM cells. Western blotting of extracts from these cultures showed the presence of the 33-kDa band but not of the high-molecular-weight components, except for the 100-kDa monomer. The 100/33-kDa combination was more abundant in arterial SM cells than in the venous counterpart. In the early phase of neointima formation, induced by endothelial injury of the carotid artery or vein-to-artery transposition, the decorin precursor was not expressed, but it was up-regulated in the SM cells of the media underlying the neointima in both models. Collectively, these data suggest a different processing/utilization of the 100-kDa monomer of proteoglycan decorin in arterial and venous SM cells, which is abolished after vein injury
Effects of ultraviolet radiation on the abundance, diversity and activity of bacterioneuston and bacterioplankton: insights from microcosm studies
The effects of ultraviolet-B (0.4 W m-2) radiation on the abundance, diversity and heterotrophic
metabolism of bacterioneuston and bacterioplankton communities from Ria de Aveiro (Portugal) were assessed and
compared to those of freshwater communities from Lake
Vela (Portugal) in microcosm experiments. Exposure to
9 h of artificial ultraviolet radiation (UVR) led to 24–33%
reduction in bacterial abundance and up to a 70% decrease
in bacterial diversity. Maximum extracellular enzyme
activity and monomer incorporation rates were reduced by
16–90% and 80–100%, respectively. Recovery of bacterial
activity during post-UV dark incubations ranged from 10 to
100% for extracellular enzyme activity and 40% for
monomer incorporation rates. In general, the heterotrophic
activity of bacterioneuston was more inhibited by UVR
than that of bacterioplankton. However, DGGE profiles
revealed greater UVR-induced reductions in the diversity
of bacterioplankton compared to bacterioneuston. The
similarity between bacterioneuston and bacterioplankton
communities in samples collected at early morning
was lower than at noon (pre-exposed communities) and
increased upon experimental irradiation, possibly indicating selection for UV-resistant bacteria. The observation
that UV exposure resulted in enhanced reduction of
bacterioneuston activity, but a lower reduction in bacterial
diversity accompanied by enhanced dark recovery potential
compared to bacterioplankton, indicates re-directioning of
bacterioneuston metabolism towards stress defence/recovery
strategies rather than the sustained heterotrophic metabolism. Our results indicate that UVR can significantly
decrease the abundance, diversity and activity of bacteria
inhabiting the surface and sub-surface layers of freshwater
and estuarine systems with potentially important impacts on
the biogeochemical cycles in these environments