Pre-mRNA splicing is functionally coupled to transcription, and genotoxic stresses can enhance alternative exon inclusion by affecting elongating RNA polymerase II. We report here that various genotoxic stress inducers, including camptothecin (CPT), inhibit the interaction between Ewing's sarcoma proto-oncoprotein (EWS), an RNA polymerase II-associated factor, and YB-1, a spliceosome-associated factor. This results in the cotranscriptional skipping of several exons of the MDM2 gene, which encodes the main p53 ubiquitin ligase. This reversible exon skipping participates in the regulation of MDM2 expression that may contribute to the accumulation of p53 during stress exposure and its rapid shut-off when stress is removed. Finally, a splicing-sensitive microarray identified numerous exons that are skipped in response to CPT and EWS-YB-1 depletion. These data demonstrate genotoxic stress-induced alteration of the communication between the transcriptional and splicing machineries, which results in widespread exon skipping and plays a central role in the genotoxic stress response.

The chemical compositions of Corsican and Sardinian Eryngium maritimum L. essential oils were investigated using column chromatography, gas chromatography with flame ionization detection and gas chromatography–mass spectrometry in electron impact mode. Sixty‐three compounds were identified accounting for 85.8–95.7% of the total amount. With germacrene D (13.7–45.9%), three uncommon oxygenated sesquiterpenes, 4βH‐cadin‐9‐en‐15‐al (18.4–27.6%), 4βH‐cadin‐9‐en‐15‐ol (2.2–14.3%) and 4βH‐muurol‐9‐en‐15‐al (4.3–9.3%), were identified as main components of the essential oils obtained from the plant aerial parts. Relative to these, essential oils from the roots differed drastically with high contents of 2,4,5‐trimethylbenzaldehyde (39.8%), 2,3,6‐trimethylbenzaldehyde (29.0%) and α‐muurolene (23.5%). The chemical variability of Corsican and Sardinian E. maritimum essential oils was studied using statistical analysis. A direct correlation between the island of origin of the sample essential oils and their chemical compositions was assessed. Corsican essential oils exhibited higher amounts of hydrocarbon terpenes than Sardinian samples. Relative to other Eryngium species, Corsican and Sardinian E. maritimum essential oils exhibited original compositions with sesquiterpene aldehydes. These compounds, together with total essential oil, were tested for antioxidant properties using the DPPH and ABTS radical‐scavenging activity tests. No meaningful activity could be attributed to sesquiterpene aldehydes and the corresponding alcohols but the total essential oil and the oxygenated fraction of E. maritimum both demonstrated strong antioxidant properties. Copyright © 2013 John Wiley & Sons, Ltd.

Alvinella pompejana is a tubicolous polychaete that dwells in the hottest part of the hydrothermal vent ecosystem in a highly variable mixture of vent (350 degrees C, anoxic, CO(2)- and sulfide-rich) and deep-sea (2 degrees C, mildly hypoxic) waters. This species has developed distinct-and specifically respiratory-adaptations to this challenging environment. An internal gas exchange system has recently been described, along with the report of an intracellular coelomic hemoglobin, in addition to the previously known extracellular vascular hemoglobin. This article reports the structure of coelomic hemoglobin and the functional properties of both hemoglobins in order to assess possible oxygen transfer. Coelomocytes contain a unique monomeric hemoglobin with a molecular weight of 14,810+/-1.5 Da, as determined by mass spectrometry. The functional properties of both hemoglobins are unexpectedly very similar under the same conditions of pH (6.1-8.2) and temperature (10 degrees -40 degrees C). The oxygen affinity of both proteins is relatively high (P50=0.66 Torr at 20 degrees C and pH 7), which facilitates oxygen uptake from the hypoxic environment. A strong Bohr effect (Phi ranging from -0.8 to -1.0) allows the release of oxygen to acidic tissues. Such similar properties imply a possible bidirectional transfer of oxygen between the two hemoglobins in the perioesophagal pouch, a mechanism that could moderate environmental variations of oxygen concentration and maintain brain oxygenation.

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