Isoenzyme replacement of glucose-6-phosphate dehydrogenase in the cytosol improves stress tolerance in plants.

In source leaves of resistant tobacco, oxidative burst and subsequent formation of hypersensitive lesions after infection with Phytophthora nicotianae was prevented by inhibition of glucose-6-phosphate dehydrogenase (G6PDH) or NADPH oxidases. This observation indicated that plant defense could benefit from improved NADPH availability due to increased G6PDH activity in the cytosol. A plastidic isoform of the G6PDH-encoding gene, G6PD, displaying high NADPH tolerance was engineered for cytosolic expression (cP2), and introduced into a susceptible cultivar.

Inhibitors of the epidermal growth factor receptor in apple juice extract.

The polyphenol-rich extract of a consumer-relevant apple juice blend was found to potently inhibit the growth of the human colon cancer cell line HT29 in vitro. The epidermal growth factor receptor (EGFR) and its subsequent signaling cascade play an important role in the regulation of cell proliferation in HT29 cells. The protein tyrosine kinase activity of an EGFR preparation was effectively inhibited by the polyphenol-rich apple juice extract.

DNA strand breaking capacity of acrylamide and glycidamide in mammalian cells.

We compared the DNA damaging potency of acrylamide (AA) and its metabolite glycidamide (GA) in the comet assay in cell systems differing with respect to species origin and cytochrome P450-depended monooxygenase (CYP2E1) expression (V79, Caco-2, primary rat hepatocytes). Only after 24 h incubation in the highest concentration of AA (6 mM) a slight but significant increase in DNA damage was observed in V79 and Caco-2 cells. In primary rat hepatocytes, however, expressing substantial amounts of CYP2E1, no induction of DNA strand breaks was found.

The substitution pattern of anthocyanidins affects different cellular signaling cascades regulating cell proliferation.

The aglycons of the most abundant anthocyanins in food, cyanidin (cy) and delphinidin (del), represent potent inhibitors of the epidermal growth factor receptor (EGFR). Structure-activity studies show that the presence of vicinal hydroxy substituents at the phenyl ring at the 2-position (B-ring) is crucial for target interaction. The presence of a single hydroxy group or introduction of methoxy substituents at the B-ring results in a substantial loss of inhibitory properties.