The Early-Middle Pleistocene environmental and climatic change and the human expansion in Western Europe: A case study with small vertebrates (Gran Dolina, Atapuerca, Spain).

The dispersal of hominins may have been favored by the opening of the landscape during the Early-Middle Pleistocene transition (EMP) in Western Europe. The structure of the small-vertebrate assemblages of the archaeo-paleontological karstic site of Gran Dolina in Atapuerca (Burgos, Spain) shows important environmental and climatic changes in the faunal succession, across the Matuyama-Brunhes boundary at 780 ka. These changes are interpreted to indicate impoverishment of the forests, along with an increase in dry meadows, and open lands in general that entailed a tendency towards the loss of diversity in small-vertebrate communities above the EMP. We evaluate variation in diversity of the faunal succession of Gran Dolina using Shannon's Second Theorem as an index of ecosystem structure. The long cultural-stratigraphic sequence of Gran Dolina during the EMP is somewhat similar in its completeness and continuity to that in the locality of Gesher Benot Ya'aqov in the Upper Jordan Valley. We also evaluate related data including faunal and floral (pollen) succession. Both localities present cold, dry and humid, warm fluctuations at the transition between the Early and the Middle Pleistocene. Comparisons between these sites present opportunities to understand large-scale climatic changes.

The 28S fraction of rRNA in molluscs displays electrophoretic behaviour different from that of mammal cells.

Electrophoresis on agarose/formaldehyde gels of rRNA in molluscs display a pattern of bands which could suggest a RNase action due to incorrect manipulation of the samples. This study shows that the disappearance of the band corresponding to the 28S fraction is due to the denaturing conditions used when electrophoresis is carried out and not to RNases action.

Identification of protein kinase C isoforms in marine mussels.

In this paper we have examined the distribution of some isoforms of protein kinase C in different tissues from the sea mussel Mytilus galloprovincialis Lmk.. By immunoblot analysis, we have detected the presence of at least three PKC isoforms, all preferably associated with the cellular cytosolic fraction. The Ca(2+)-independent form PKC delta was separated from the Ca(2+)-dependent forms (PKC alpha and beta) by means of an ionic change chromatography on DE-52. A comparative study was carried out on the phosphorylatable non-artificial substrates. The M.B.P. protein proved to be the best substrate, while the worst was HIIIS histone which, however, is frequently used in evaluation assays of the activity.

Levels of L-T3 in maternal and foetal compartments following experimental modifications of the maternal thyroid state in rats.

In pregnant female rats, concentrations of tri-iodo-L-thyronine in maternal serum, amniotic fluid and placental tissue after 15, 18 and 20 days of gestation were measured by homologous radioimmune-analysis. The three experimental groups of pregnant rats were: 1) euthyroid (or control), 2) hypothyroid, provoked by iodine-deficient diet for two months before conception and during gestation, 3) hyperthyroid, provoked by subcutaneous injections of L-thyroxine during gestation. Maternal serum L-T3 was measured in order to check the thyroid state. Significant decreases in L-T3 concentrations were found at all stages of gestation in the amniotic fluid of hypothyroid group. The hormonal concentrations in the placental tissues were correlated with the different treatments (decreased in hypothyroid state and increased in hyperthyroid state). This could suggest that the transfer of maternal iodothyronines to the foetus influences its foetal thyroid development.

The urokinase plasminogen activator receptor-associated protein/endo180 is coexpressed with its interaction partners urokinase plasminogen activator receptor and matrix metalloprotease-13 during osteogenesis.

The urokinase plasminogen activator receptor-associated protein/Endo180 (uPARAP/Endo180) is a newly discovered member of the macrophage mannose receptor family that was reported to interact with ligand-bound urokinase plasminogen activator receptor (uPAR), matrix metalloprotease-13 (MMP-13), and collagen V on the cell surface. We have determined the sites of expression of this novel receptor during murine postimplantation development. uPARAP/Endo180 was expressed in all tissues undergoing primary ossification, including the developing bones of the viscerocranium and calvarium that ossify intramembranously, and developing long bones undergoing endochondral ossification. uPARAP/Endo180 mRNA was expressed by both immature osteoblasts and by mature osteocalcin-producing osteoblasts-osteocytes, and was coexpressed with MMP-13. Interestingly, osteoblasts also expressed uPAR. Besides bone-forming tissues, uPARAP/Endo180 expression was detected only in a mesenchymal condensation of the midbrain and in the developing lungs. The data suggest a function of this novel protease receptor in bone development, possibly mediated through its interactions with uPAR, MMP-13, or collagen V.