Nutzung der induzierbaren Genexpression des NematodenCaenorhabditis elegans als Biomonitor

The soil nematodeCaenorhabditis elegans is one of the simplest animals having the status of a laboratory model. Its already completely sequenced genome contains the remarkable number of 80 cytochrome P450 genes (CYP) and many further genes coding for enzymes involved in biotransformation. In order to study xenobiotically induced gene expression inC. elegans, liquid cultures were exposed to different, well-known xenobiotic inducers. The mRNA expression was detected by two different types of DNA arrays and semi-quantitative RT-PCR. β-naphthoflavone, PCB52 and lansoprazol were the most active and, in particular, induced almost all CYP35 isoforms strongly. In conclusion, the xenobiotic dependent gene expression ofC. elegans is a useful tool to reveal defense mechanisms against potential damaging substances as well as for developing a biomonitoring system.     

Managing the offspring environment: brood care in the bromeliad crab,Metopaulias depressus

Summary Maternal modification of the larval environment was studied in the bromeliad crab, Metopaulias depressus (Decapoda, Grapsidae). The bromeliad crab breeds in rain water stored in the leaf axils of large Jamaican bromeliads. The physico-chemical water conditions are highly unfavorable for the development of the larvae. Water in nursery axils contained no leaf litter and up to 14 empty snail shells, whereas other axils were partly or completely covered with leaf litter and rarely held snail shells. Mother crabs removed leaf litter from nursery axils, and occasionally from neighboring axils. Nursery axils contained twice as much dissolved oxygen (DO₂) at night when DO₂ is at a minimum, and less dissolved carbon dioxide (DCO₂) than axils unattended by a crab. The higher DO₂ content in nurseries meets the respiratory needs of an average sized brood, but the lower concentration in axils with litter may not. It is suggested that the higher DO₂ and lower DCO₂ concentrations in the nursery axils result from a water circulation produced by the mother and her leaf litter cleaning behavior. The low pH and the Ca²⁺ content in the water of unattended bromeliad axils are unfavorable for development of larvae and young. Mother crabs significantly increased pH and Ca²⁺ by adding empty snail shells to the nursery-axil water. In experiments where the brood was transferred to other axils, mothers switched from the nursery axil to the new axil containing the brood, and there continued caring for their offspring.     

Mineralölkohlenwasserstoffe im Boden bei der Sanierung von Altlasten

Various analyses and evaluative procedures are used to provide evidence of success using remediation procedures. Because of the lack of standardized procedures for soil assessment, general practice has unfortunately propagated the use of DIN standards for determining the level of similar parameters in water as well as for other heterogeneous matrices (e.g. in soil). A precise auditing of quality, however, has not been possible with this method, this procedure has even put the success of such a remediation into question. This article describes the problems of determining mineral hydrocarbon concentrations on soil as well as portraying the remediation of oil damages which has occurred on a site of a former waste oil redestillation facility [1, 2]. This procedure has been proved in practice and serves as a model because an adequately defined, standardized method (DIN standard) is lacking.