Fluorescent Biosensor of CDK5 Kinase Activity in Glioblastoma Cell Extracts and Living Cells

CDK5 plays a major role in neuronal functions, and is hyperactivated in neurodegenerative pathologies as well as in glioblastoma and neuroblastoma. Although this kinase constitutes an established biomarker and pharmacological target, there are few means of probing its activity in cell extracts or in living cells. To this aim a fluorescent peptide reporter of CDK5 kinase activity, derived from a library of CDK5‐specific substrates, is engineered and its ability to respond to recombinant CDK5/p25 is established and CDK5 activity in glioblastoma cell extracts is reported on through sensitive changes in fluorescence intensity. A cell‐penetrating variant of this biosensor which can be implemented to image CDK5 activation dynamics in space and in time is further implemented. This original biosensor constitutes a potent tool for quantifying differences in CDK5 activity following treatment with selective inhibitors and for monitoring CDK5 activation, following inhibition or stimulation, in a physiologically relevant environment. As such it offers attractive opportunities to develop a diagnostic assay for neuronal pathologies associated with hyperactivated CDK5, as well as a companion assay to evaluate response to new therapies targeting this kinase.     

Survival and adhesion ability of <Emphasis Type="Italic">Shigella</Emphasis> spp. strains after their incubation in seawater microcosms

In this study, we investigated the survival and adhesion ability of Shigella after their incubation in seawater microcosms at ambient temperature and at 4°C during 1 month. Our results showed that the number of cells was considerably decreased after this period of stress. In addition, we have revealed some modifications in the biochemical and enzymatic profiles of stressed cells. These modification were noted by the appearance or/and the disappearance of some activities. Indeed, antibiotic susceptibility of stressed cells has been changed. Adherence assays to KB cells showed on increase in the number of adherent cells from 0.7 to 6.7% after 1 month of incubation in seawater.     

Effects of Water Depth,Seasonal Exposure,and Substrate Orientation on Microbial Bioerosion in the Ionian Sea (Eastern Mediterranean)

The effects of water depth, seasonal exposure, and substrate orientation on microbioerosion were studied by means of a settlement experiment deployed in 15, 50, 100, and 250 m water depth south-west of the Peloponnese Peninsula (Greece). At each depth, an experimental platform was exposed for a summer period, a winter period, and about an entire year. On the up- and down-facing side of each platform, substrates were fixed to document the succession of bioerosion traces, and to measure variations in bioerosion and accretion rates. In total, 29 different bioerosion traces were recorded revealing a dominance of microborings produced by phototrophic and organotrophic microendoliths, complemented by few macroborings, attachment scars, and grazing traces. The highest bioerosion activity was recorded in 15 m up-facing substrates in the shallow euphotic zone, largely driven by phototrophic cyanobacteria. Towards the chlorophyte-dominated deep euphotic to dysphotic zones and the organotroph-dominated aphotic zone the intensity of bioerosion and the diversity of bioerosion traces strongly decreased. During summer the activity of phototrophs was higher than during winter, which was likely stimulated by enhanced light availability due to more hours of daylight and increased irradiance angles. Stable water column stratification and a resulting nutrient depletion in shallow water led to lower turbidity levels and caused a shift in the photic zonation that was reflected by more phototrophs being active at greater depth. With respect to the subordinate bioerosion activity of organotrophs, fluctuations in temperature and the trophic regime were assumed to be the main seasonal controls. The observed patterns in overall bioeroder distribution and abundance were mirrored by the calculated carbonate budget with bioerosion rates exceeding carbonate accretion rates in shallow water and distinctly higher bioerosion rates at all depths during summer. These findings highlight the relevance of bioerosion and accretion for the carbonate budget of the Ionian Sea.     

Sediments and sedimentary history of Lake Attersee (Salzkammergut,Austria)

Attersee represents a good example of a lake situated in the Northern forelands of the Northern Calcareous Alps and influenced by different sediment-supplying processes during the postglacial. Several compounds, of different origin, form the sediments of the basin. Clastics which are mainly composed of dolomites derive from the Northern Calcareous Alps. Clastic input of organic and inorganic particles is accomplished by rivers and landslides. They are responsible for the main input of siliciclasts like quartz, feldspar and mica. A high proportion of the sediment results from autochthonous biogenic carbonate precipitation. In the shallow sublittoral areas of the northern part of the lake benthic decalcification caused by encrusting macro- and micro-phytes is dominant, while in the southern and central parts of the lake epilimnetic decalcification caused by the blooming of phytoplancton is more important during summer. The total biogenic calcium carbonate production reaches about 11 000 to 12 000 metric tons a year.Nutrients and residues of cyanophytes (Oscillatoria rubescens) deriving from the eutrophic lake Mondsee were washed into lake Attersee by the Mondseeache. High amount of phosphorus in the sediments of the southern basin depicts local eutrophication in the mouth area of the Mondseeache. The average sedimentation rate in lake Attersee can be determined by different dating methods. Sedimentation rates increased during the last 110 years from 1 mm a year to 1.8–2 mm a year as a result of human activities. Five main phases in the postglacial sedimentary history can be recognized: Würm moraines and finely banded varves (before 13 000 B.P.), the early Attersee stage (from 13 000 B.P. up to 1200 B.P.), and the later Attersee stage after the Bavarian colonization (from 1200 B.P. on). Using heavy metal and isotope analyses the sedimentary history can be reconstructed in more detail for the last 100 years.     

Cost-Effectiveness Analysis of Sofosbuvir Compared to Current Standard Treatment in Swiss Patients with Chronic Hepatitis C

In clinical trials, sofosbuvir showed high antiviral activity in patients infected with hepatitis C virus (HCV) across all genotypes. We aimed to determine the cost-effectiveness of sofosbuvir-based treatment compared to current standard treatment in mono-infected patients with chronic hepatitis C (CHC) genotypes 1–4 in Switzerland. Cost-effectiveness was modelled from the perspective of the Swiss health care system using a lifetime Markov model. Incremental cost-effectiveness ratios (ICERs) used an endpoint of cost per quality-adjusted life year (QALY) gained. Treatment characteristics, quality of life, and transition probabilities were obtained from published literature. Country-specific model inputs such as patient characteristics, mortality and costs were obtained from Swiss sources. We performed extensive sensitivity analyses. Costs and effects were discounted at 3% (range: 0–5%) per year. Sofosbuvir-containing treatment in mixed cohorts of cirrhotic and non-cirrhotic patients with CHC genotypes 1–4 showed ICERs between CHF 10,337 and CHF 91,570 per QALY gained. In subgroup analyses, sofosbuvir dominated telaprevir- and boceprevir-containing treatment in treatment-naïve genotype 1 cirrhotic patients. ICERs of sofosbuvir were above CHF 100,000 per QALY in treatment-naïve, interferon eligible, non-cirrhotic patients infected with genotypes 2 or 3. In deterministic and probabilistic sensitivity analyses, results were generally robust. From a Swiss health care system perspective, treatment of mixed cohorts of cirrhotic and non-cirrhotic patients with CHC genotypes 1–4 with sofosbuvir-containing treatment versus standard treatment would be cost-effective if a threshold of CHF 100,000 per QALY was assumed.