Ecochemical assessment of environmental chemicals: Draft guideline of the test procedure to evaluate metabolism and degradationof chemicals by plant cell cultures

A guideline is drafted describing the screening procedure in detail. The aim for this is to facilitate an adoption of this test by bodies supervising environmental chemicals. Successful introduction of this method into the respective laboratories will cause no problems, as the procedure has been collaboratively established and improved.     

Behavior of PAHs during cold storage of historically contaminated soil samples

The stability of historically polycyclic aromatic hydrocarbon (PAH)-contaminated soils during cold storage was investigated. Samples from two former manufactured gas plants exhibited quantitative recoveries of PAHs over the whole period of sample holding at 4 °C in the dark (8–10 months), whereas significant losses of PAHs were observed for soils received from a former railroad sleeper preservation plant with low molecular weight compounds being notably more affected compared to heavier PAHs. Already after 2 weeks of holding time, 3-ring PAHs in one of theses samples were down to 29–73% of the initial concentration and significant losses were observed for up to 5-ring compounds. Dissipation of PAHs was found to be predominantly due to aerobic microbial metabolism since sodium azide poisoned samples showed quantitative recoveries for all PAHs over the entire storage time of 3 months. A similar stabilizing effect was observed for freezing at −20 °C as means of preservation. Except for acenaphthene, no significant loss for any of the PAHs was observed over 6 weeks of holding time. Eventually, selected chemical, physical, and biological parameters of two soils were investigated and identified as potential indicators for the stability of PAH-contaminated soil samples.     

Production of reactive oxygen species and 8-hydroxy-2'deoxyguanosine in KB cells co-exposed to benzo[a]pyrene and UV-A radiation

Previous studies have shown that ultraviolet (UV) A light and the polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) can synergistically enhance the formation of 8-hydroxy-2'deoxyguanosine (8-OHdG) in living cells. It has been postulated that the underlying mechanism is production of reactive oxygen species (ROS) via photosensitization, but direct evidence supporting this hypothesis has been lacking. This study examined intracellular ROS production in living cells co-exposed to UV-A and BaP as well as the relationship between intracellular production of ROS and formation of 8-OHdG. KB cells were exposed to BaP for 24 h, followed by exposure to UV-A (365 nm) or UV-B (312 nm). The levels of intracellular ROS were directly measured by use of the fluorescent probe dihydrorhodamine 123 (DHR-123) in flow cytometry. Levels of 8-OHdG were measured by high performance liquid chromatography coupled with electrochemical detection (HPLC-ECD). The results demonstrated that UV-B itself induced a much greater level of intracellular ROS than did UV-A alone under the same dose of energy (0.10 mW/cm(2), 20 min). The presence of BaP (13.3 microM) substantially increased ROS production in UV-A-treated cells (2.9-fold), but only slightly enhanced ROS production in UV-B-treated cells (1.3-fold). These results show that BaP acts mainly as a photosensitizer of UV-A, but not UV-B. Furthermore, greater intracellular ROS production was proportional to both BaP concentration and UV-A dosage. There was a linear relationship between ROS production and 8-OHdG formation in cells co-exposed to BaP and UV-A. Results of this study suggest that UV-A and BaP act synergistically to enhance ROS production and formation of 8-OHdG, resulting in increased DNA damage.     

Langfristigkeit ?kosystemarer Forschung

Zusammenfassung  Nach wie vor findet der Faktor Zeit in den Umweltwissenschaften zu wenig Beachtung. Langfristige Beobachtungen und Me?reihen in der ?kologischen Forschung, wie sie für die Bewertung und Prognosen von Umweltzust?nden und-entwicklunger, unabdingbar w?ren, scheinen die Ausnahme zu sein. Besonders komplexe ?kosysteme, wie terrestrische oder marine Systeme, kennzeichnen sich auch durch l?ngere natürliche Eigenzeiten, die deshalb bei ihrer Erforschung berücksichtigt werden mü?ten. In diesem Zusammenhang soll verdeutlicht werden, welche Rolle zeitliche Parameter speziell in der terrestrischen ?kosystemforschung spielen. Zu diesem Zweck wurde eine Datenbank konzipiert, die Hauptcharakteristika von ?kosystemaren Analysen aufnehmen kann. Forschungsberichte verschiedener ?kosystemforschungszentren wurden zur Aufnahme in die Datenbank bearbeitet. Gezielte Abfragen auf den Datenpool erm?glichen dann eine Auswertung hinsichtlich der zeitlichen Ausrichtung bestimmter Untersuchungen. Dabei stellte sich — neben einer teilweisen Ungleichheit der Zeitskalen von Experiment und Realit?t — u.a. heraus, da? l?ngerfristige Untersuchungen ?u?erst selten durchgeführt werden. So vielf?ltig die Gründe für dieses Defizit auch sein m?gen, sie k?nnen nicht von der Forderung nach st?rkerer Berücksichtigung von langzeitlichen Beobachtungen ablenken, will die ?kosystemforschung die an sie gestellten Aufgaben erfüllen.      

Laboratory rearing of Sepiolinae (Mollusca: Cephalopoda)

Five species of Sepiola and Sepictta were reared in the laboratory from egg to adult size. Spawning was achieved in 3 species of Sepiola after 5 to 7 months. The growth rate of the species reared did not depend upon temperature, which ranged from 12.5° to 20°C. A fairly constant size increase (2.5 mm mantle length/month) was observed in Sepiola during the 5 months after hatching. In Sepietta, the same growth rate was observed until the fourth month after hatching, when it increased to the rate of 5 mm mantle length/month.Laboratoire associé au C.N.R.S.