Effect of ripening temperature on the chemical composition of lingonberries (Vaccinium vitis-idaea L.) of northern and southern origin.

Lingonberries (Vaccinium vitis-idaea L.) from two locations, northern (69°N, 18°E) and southern (59°N, 10°E) Norway, were grown under controlled conditions in a phytotron at two temperatures (9 and 15 °C) to study the effects of the ripening temperature and origin on the chemical composition of the berries. The concentrations of phenolic compounds, sugars, and organic acids as well as the profile of volatile organic compounds (VOCs) were determined using chromatographic and mass spectrometric methods. Five anthocyanins, eleven flavonols, eight cinnamic acid derivatives, three flavan-3-ols, three sugars, three organic acids, and 77 VOCs were identified, of which 40 VOCs had not previously been reported in lingonberries. Berries from both locations, were found to have higher contents of anthocyanins and cinnamic acid derivatives when ripened at lower temperature (9 °C), compared to the higher temperature (15 °C). Lingonberries of northern origin had a different VOC profile and higher contents of anthocyanins and organic acids than berries originating from the south. Lingonberries from the northern location also had higher proportions of cyanidin-3-O-glucoside and cyanidin-3-O-arabinoside than lingonberries from the southern location. The results show that the composition of lingonberries is influenced by both the environment and the origin of the plants, with phenolic compounds mainly influenced by the growth temperature and VOCs mainly influenced by plant origin.

Biofilm formation and virulence of uropathogenic Escherichia coli in urine after consumption of cranberry-lingonberry juice.

Cranberry-lingonberry juice (CLJ) was effective in preventing urinary tract infections (UTIs) in our earlier randomized clinical trial. We aimed to test whether consumption of CLJ at a similar dose to earlier reduces the biofilm formation and virulence of uropathogenic Escherichia coli in urine. Twenty healthy women drank 100 ml of CLJ daily for two weeks. Urine samples were obtained 2-4 hours after the last dose. Control samples were taken after a one-week period without berry consumption. Biofilm formation of 20 E. coli strains was measured at 72 hours by the polystyrene microtitre plate method. Quantitative real-time PCR analyses were performed for selected genes. Four of the 20 clinical strains produced more biofilm in urine after CLJ consumption (P < 0.05) and one produced less. Expression levels of the pga, cpxA, fimA and papF genes did not differ between bacteria grown in control urine and urine obtained after CLJ consumption, except for pga gene expression, which was reduced in one strain after CLJ (P = 0.04). It appears that the effect of CLJ in preventing UTIs is not explained by mechanisms that reduce biofilm formation or the expression of selected virulence genes of Escherichia coli in urine.

Isolation of high quality RNA from bilberry (Vaccinium myrtillus L.) fruit.

A simple and efficient method is described for isolating high quality RNA from bilberry fruit. The procedure is based on the use of hexadecyltrimethyl ammonium bromide (CTAB), polyvinylpyrrolidone (PVP), and beta-mercaptoethanol in an extraction buffer in order to eliminate the polysaccharides and prevent the oxidation of phenolic compounds. This method is a modification of the one described for pine trees, and yields high-quality RNA suitable for cDNA based methodologies. This method is applicable for a variety of plant tissues.