Sample-specific inhibition and in vitro transcription efficiency were determined by quantification of spiked external RNA standard to each RNA extract and its quantification by a specific qPCR assay (Wieczorek et al., 2011). Cellulose and cellobiose were degraded under both oxic and anoxic conditions (Figs 1 and 2; Fig. S1). Products of cellulose hydrolysis (cellobiose or glucose) were not detected (≤ 0.5 μmol gsoil

DW−1) suggesting an efficient assimilation of hydrolysis products. Small amounts of acetate, propionate, and butyrate accumulated in anoxic cellulose-supplemented microcosms (< 5 μmol gsoilDW−1), and ferrous iron formation was stimulated, i.e. ferric iron reducers were active (Fig. 1). Similar product Torin 1 profiles have been observed previously in other aerated soils (Küsel & Drake, 1995; Küsel et al., 2002). Hydrolysis of supplemental cellobiose led to a transient accumulation of glucose (Fig. 2; Fig. S2; Table S2) and could have been caused by β–glucosidases that were released by cellulolytic aerobes (Lynd et al., 2002) under the preceding oxic conditions. Traces of molecular hydrogen were detected in cellobiose-supplemented

microcosms (Fig. 2; Fig. S1), and pH ranged from 4.7 to 6.2 (data not shown). Cellulose degradation was analysed only at high herbicide concentrations (Fig. 1) and revealed that both pesticides have the potential to impair cellulose degradation at oxic and anoxic conditions. The toxic effect of Bentazon and MCPA on cellobiose degradation under oxic conditions was only apparent at concentrations above values that are typical Selleckchem SCH772984 of crop field soils. At typical in situ herbicide concentrations, inhibition of aerobic cellobiose degradation

was not apparent (Fig. 2; Table S3). Under anoxic conditions, Bentazon and MCPA impaired consumption of glucose in cellobiose-supplemented soil microcosms (Figs 1 and 2). Cellobiose consumption rates were not affected (Table S3). This toxic Histone demethylase effect was observed at high and low herbicide concentrations (Figs 1 and 2; Fig. S1). Concentrations of formed organic acids (i.e. acetate, propionate, butyrate) were below the quantification limit (i.e. < 1.5 μmol gsoil DW−1 in total) (data not shown). The production of carbon dioxide and molecular hydrogen was decreased up to 85% and 100%, respectively, and ferrous iron production was negligible (Table S3). Thus, anaerobic cellulose-degradation was highly sensitive to the toxicity of both herbicides. The findings on the toxic effects of the tested two herbicides agree with observations (1) that MCPA that was applied at the recommended dose did not affect either carbon dioxide production, or oxygen uptake or N-mineralization in an cropland soil and (2) that aerobic cellulose degradation was only slightly decreased even when MCPA was spread directly on cellulose sheets (Grossbard, 1971; Schröder, 1979). Nonetheless, reduction of nitrogen mineralization and soil respiration (i.e.