Besteht die Möglichkeit zur Übertragung von AIDS durch blutsaugende Insekten?

The question whether the possibility exists of transmission of HIV by hematophagous insects from infected to uninfected persons is a point of very intensive discussion. The solution of this problem could help to explain the spreading of the disease in human populations and could contribute to an understanding of the evolution of AIDS and the possible transfer from wild primates into human populations. The classical routes of pathogen transmission by blood-sucking arthropods are either "mechanical" or "biological". Both ways are rejected, the latter since no replication of the retro-virus in the vector exists and its survival in the arthropod is very limited. Based on long experimental experience with biting flies as well as with plant-sucking insects a third hitherto neglected way of transmission by regurgitation of gut content can be introduced. Since regurgitation is neither "mechanical" nor "biological", "regurgitative transmission" must be introduced as an additional term.     

Extreme34S-Anreicherungen in gelöstem Sulfat von Grundwässern im Umfeld einer Altmülldeponie

Wir danken Dr. Kerndorff für die kritische Durchsicht des Manuskripts.     

Persistence of Eclosion Rhythm in Drosophila melanogaster After 600 Generations in an Aperiodic Environment

 The ubiquity of circadian rhythms suggests that they have an intrinsic adaptive value (Ouyang et al. 1998; Ronneberg and Foster 1997). Some experiments have shown that organisms have enhanced longevity, development time or growth rates when maintained in environments whose periodicity closely matches their endogenous period (Aschoff et al. 1971; Highkin and Hanson 1954; Hillman 1956; Pittendrigh and Minis 1972; Went 1960). So far there has been no experimental evidence to show that circadian rhythms per se (i.e. periodicity itself, as opposed to phasing properties of a rhythm) confer a fitness advantage. We show that the circadian eclosion rhythm persists in a population of the fruitfly Drosophila melanogaster maintained in constant conditions of light, temperature, and humidity for over 600 generations. The results suggest that even in the absence of any environmental cycle there exists some intrinsic fitness value of circadian rhythms. Received: 2 November 1998 / Accepted in revised form: 22 April 1999     

Forest ecosystem development in post-mining landscapes: a case study of the Lusatian lignite district

The restoration of surface mining landscapes requires the (re)creation of ecosystems. In Lusatia (eastern Germany), large-scale open-cast lignite mining operations generated spoil dumps widely consisting of acidified, phytotoxic substrates. Amelioration and rehabilitation measures have been developed and applied to these substrates since the 1950s. However, it is still not clear whether these approaches are sustainable. This paper reports on collaborative research work into the ecological potential of forest ecosystem development on typical minesites in the Lusatian lignite district. At first sight, pine stands on minesites along a chronosequence comprising about 35 years did not show differences when compared with stands on non-mined sites of the general region. Furthermore, with some modification, conceptual models for flora and fauna succession in forest stands on non-mined sites seem to be applicable, at least for the early stages of forest ecosystem development. For example, soil organism abundance and activity at minesites had already reached levels typical of non-mined sites after about 20-30 years. In contrast, mine soils are very different from non-mined soils of the test region. Chemically, mine soil development is dominated by processes originating from pyrite oxidation. Geogenic, i.e. lignitic, soil organic carbon was shown to substitute for some functions of pedogenic soil organic matter. Rooting was hampered but not completely impeded in strongly acidified soil compartments. Roots and mycorrhizae are apparently able to make use of the characteristic heterogeneity of young mine soils. Considering these recent results and the knowledge accumulated during more than 30 years of research on minesite rehabilitation internationally, it can be stated that minesite restoration might be used as an ideal case study for forest ecosystem development starting at "point zero" on "terra nova".     

Activities of alkaline phosphatase in first trimester chorion biopsy tissue

We have determined the activity of alkaline phosphatase in chorionic villous tissue obtained in the first trimester of pregnancy, in order to obtain the normal range of values as a prerequisite for application to the prenatal diagnosis of the rare bone disease hypophosphatasia. The activities found were a combination of intestinal and liver/bone/kidney types; traces of placental type were present in only one sample.     

Assessment and management of fetal agenesis of the corpus callosum

Prenatal counselling for fetal agenesis of the corpus callosum is difficult as the prognosis until now has been so uncertain. We have reviewed the current world English literature to provide the best probabilistic information for prospective parents. In total, there are 70 cases where the diagnosis was made prenatally. The diagnosis of apparently isolated agenesis of the corpus callosum (in the absence of other sonographically detectable anomalies) appears to carry an excellent prognosis, with an 85 per cent chance of a normal developmental outcome and a 15 per cent risk of handicap. Fetal karyotyping is recommended as there is a 1 in 10 risk of aneuploidy. If other anomalies are detected prenatally, the outcome is very poor. Termination of pregnancy is advised in these circumstances.