Steroids originating from bacterial bile acid degradation affect Caenorhabditis elegans and indicate potential risks for the fauna of manured soils.

Bile acids are steroid compounds from the digestive tracts of vertebrates that enter agricultural environments in unusual high amounts with manure. Bacteria degrading bile acids can readily be isolated from soils and waters including agricultural areas. Under laboratory conditions, these bacteria transiently release steroid compounds as degradation intermediates into the environment. These compounds include androstadienediones (ADDs), which are C19-steroids with potential hormonal effects. Experiments with Caenorhabditis elegans showed that ADDs derived from bacterial bile acid degradation had effects on its tactile response, reproduction rate, and developmental speed. Additional experiments with a deletion mutant as well as transcriptomic analyses indicated that these effects might be conveyed by the putative testosterone receptor NHR-69. Soil microcosms showed that the natural microflora of agricultural soil is readily induced for bile acid degradation accompanied by the transient release of steroid intermediates. Establishment of a model system with a Pseudomonas strain and C. elegans in sand microcosms indicated transient release of ADDs during the course of bile acid degradation and negative effects on the reproduction rate of the nematode. This proof-of-principle study points at bacterial degradation of manure-derived bile acids as a potential and so-far overlooked risk for invertebrates in agricultural soils.

[Detection of rupture of fetal membranes using a commercially available fibronectin test kit]. / Zum Nachweis des Blasensprungs mit Hilfe eines kommerziell erhältlichen Fibronectin-Nachweistests.

In a clinical examination an attempt was made to confirm the aptitude of a commercially available immunoassay to detect amniotic fluid. Pure amniotic fluid gained by amniocentesis, not mixed with other secretions, was used. On examination using three different batches the sensitivity of this test amounted to 35/55 in all, or 64%. We came to the conclusion that the present test was not sufficiently reliable to prove or disprove the discharge of amniotic fluid. An explanation is needed especially regarding the role played by the forces which occur during contractions and the presence of cervical and vaginal secretions when fetal fibronectin is found to be present. The evidence of fetal fibronectin could possibly become more important as a predictor of imminent labour than as being proof of the admixture of amniotic fluid in cervical and vaginal secretions.