Modification of a promiscuous inhibitor shifts the inhibition from γ-secretase to FLT-3

The inhibition of FLT-3 activity is an interesting target for the treatment of acute myeloid leukemia (AML). The serendipitous identification of FLT-3 inhibitors from a CK1/γ-secretase programme provided compounds with dual inhibitory activity. We analyzed the structure–activity relationship of these inhibitors and derivatized them to arrive at compounds with reduced impact on γ-secretase activity and enhanced FLT-3 inhibition.     

Immobilization in quartz fiber felt reinforced silica aerogel improves the activity of Candida rugosa lipase in organic solvents

Candida rugosa lipase is a very useful catalyst, but its rapid inactivation by simple alcohols is a drawback. The present study was focussed on the encapsulation of this enzyme in silica aerogels reinforced with quartz fiber felt. The activity of the immobilized lipase in an organic solvent could be significantly improved over that of the free enzyme and of previous immobilization techniques, by evaporating the alcohol formed during a pre-hydrolysis of the silica precursor, before adding the aqueous enzyme solution. The alcohol evaporation technique was previously used by other authors to immobilized enzymes, but applied to xerogels dried by evaporation, while in the present case the wet gels obtained were dried by the CO₂ supercritical method to obtain aerogels. Besides, such silica aerogels were also reinforced by impregnating a commercial ceramic quartz fiber felt of St. Gobain with the silica sol containing the enzyme, before gelation. The ceramic composites heterogeneous biocatalysts obtained could be used for a large number of times without any apparent deterioration.     

Some Tools to Analyze Changes of Rhythms in Biological Time Series

The moving window principle applied to the khi-square periodogram allows, through local successive examinations, a comprehensive study of the biological time series. This method puts forward several cases of transition linked to environmental or physiological changes. Furthermore, we applied the Grassberger and Procaccia method (1983) for the analysis of more complex transition problems. The method helps to detect chaotic properties in behavioral activity rhythms.     

Immediate response to translocation without acclimation from captivity to the wild in Hermann’s tortoise

Survival, reproductive and recruitment rates, along with health status, of translocated and resident individuals should be evaluated. However, gathering this information poses logistical constraints and requires long-term studies. Considering the urgent nature of many species’ situations where translocation would be appropriate, fast-assessment techniques should be tested. We assessed the immediate response to translocation of Hermann’s tortoises (Testudo hermanni hermanni) directly from captivity to the wild. Individuals were maintained in captivity 2 to 8 years before being released in spring 2013 into a natural population impacted by fire. During the critical 3 months post-release period, we radio-tracked translocated individuals (N?=?12) and resident tortoises in spring 2013 (N?=?14), plus another batch of resident tortoises in spring 2012 (N?=?9). Movements, behaviours, body condition and body temperature were regularly recorded. All translocated tortoises acclimated well to their novel environment. We found no differences in movement, thermoregulation and body condition between translocated and resident tortoises. Body condition of all tortoises increased rapidly in spring. We found no sign of perturbation in resident tortoises. Contrarily, resident males mated with translocated females. Translocations should be further tested on larger spatial and time scales to improve population restoration programmes, especially in threatened species with limited dispersal ability.     

Using stone cover patches and grazing exclusion to restore ground-active beetle communities in a degraded pseudo-steppe

The dry grasslands of La Crau, a pseudo-steppe ecosystem located in Southern France, have experienced drastic reduction and degradation due to intensive agricultural activities for the past 50 years, leading to changes in their beetle assemblage. This valuable ecosystem is characterized by 50% stone cover, consisting of remnants from an old riverbed, and centuries-old sheep grazing. However, much of the stone cover has been removed for the purposes of cultivation. With the aim of restoring this ecosystem, we manipulated these two principal ecological factors: sheep grazing (grazing/exclusion) and stone cover (50% stone cover/no large stones). This study was conducted on a former cultivated field and on a pseudo-steppe area. On each of the two areas, 12 experimental units contained four different treatment patches: (1) stones × grazing, (2) no stones × grazing, (3) no stones × no grazing and (4) stones × no grazing, were randomly positioned. Data were obtained from 96 pitfall traps (one on each patch). After 4 years, restored stone cover combined with grazing exclusion significantly improved beetle abundance and increased beetle richness (38 species vs. 22 in the grazed-no-stones treatment), whereas no significant differences were recorded in the three other treatments. Our results therefore suggest that removing grazing for a few years and restoring stone cover is a promising method to restore beetle assemblages in this type of ecosystem.     

The angiotensin AT2 receptor modulates T-type calcium current in non-differentiated NG108-15 cells.

We report here that angiotensin II (AII) and the AT2 receptor-selective ligand, CGP 42112, modulate the T-type calcium current in non-differentiated NG108-15 cells, which express only AT2 receptors. Both peptides decrease the T-type calcium current at membrane potentials above -40 mV and shift the current-voltage curve at lower potentials with maximal effect between 5 and 10 min after application. These data describe a new cellular response to AII and suggest that the AT2 receptor mediates certain neurophysiological actions of this hormone.