The substrates used by sulphate-reducing bacteria in sediment slurries from Loch Eil, Loch Etive and the Tay estuary were determined by selectively inhibiting sulphate reduction with 20 mM-molybdate and measuring the resultant substrate accumulation. Substrate accumulation was linear after molybdate addition, and the rate of accumulation closely matched sulphate reduction rates, indicating that metabolic pathways other than those specifically involving sulphate reduction were not affected by the inhibitor. In sediments from all three sites acetate was a major substrate, although the percentage of sulphate reduced due to acetate oxidation varied considerably among the sites (Tay estuary, 35%; Loch Eil, 64%; Loch Etive, 100%). In addition to acetate, 17 individual substrates were shown to be involved in sulphate reduction to varying extents in the Tay estuary and Loch Eil sediments; these included lactate, H2, propionate, iso-and n-butyrate, iso-and n-valerate, 2-methylbutyrate and amino acids. At both sites propionate accounted for between 6 and 12% of sulphate reduction. Butyrate (n-and iso-), iso-valerate and 2-methylbutyrate were of approximately equal importance at each site and together accounted for 13 and 11 %, respectively, of the sulphate reduction in the Tay estuary and Loch Eil sediments. Lactate was only important in the Tay estuary sediments, where it accounted for 43 % of sulphate reduction. The rate of accumulation of amino acids was greatest in the Tay estuary sediments, but the contribution of amino acids to sulphate reduction was higher in the Loch Eil(9 %) than in the Tay estuary sediments (2 %). Of the 21 individual amino acids that were measured there was a linear increase in nine; the most important of these were serine, glutamate and arginine. In general, when sulphate reduction rates were high the substrates for this process were more varied than when rates were low. Combining the results of two experiments and assuming complete degradation of the individual substrates, almost all the sulphate reduction could be accounted for at each site (Tay estuary, 101 %; Loch Eil, 98%; Loch Etive, > 100%).

No abstract

The new Soxflo instrument was evaluated for the determination of crude fat in foods and animal feeds. Samples are packed into small columns and extracted with petroleum ether at room temperature. The Soxflo yielded accurate data from foods, ranging from 0.4 to 73.2% crude fat, compared with Soxhlet extractions and Certified Reference Materials, for which recoveries averaged 99.7 and 100.7%, respectively. Relative standard deviations (1.81 %) were approximately half those of Soxhlet extractions (3.68%). Regression analysis of the data suggested that there was no proportional bias. A small but acceptable constant bias was measured. Soxflo extractions are easy to perform and take approximately 1 h to complete. The main difference between the Soxflo and Soxhlet techniques lies in the extraction procedure. Estimated savings during extractions are in time (85% reduction), energy (95%), cooling water (100%), and solvents (50%). Soxflo extractions are, therefore, more environmentally friendly than Soxhlet extractions.

Reading's research outputs online Feeding of carob (Ceratonia siliqua) to sheep infected with gastrointestinal nematodes reduces faecal egg counts and worm fecundity

Significance and Impact of the Study: This study showed that condensed tannins (CTs), which were a group of secondary metabolites of many plants and rich in prodelphinidins (PD), had greater antibacterial activity against avian pathogenic Escherichia coli (APEC) than CTs that were rich in procyanidins (PC). The mode of action of the CTs was to inhibit the swimming and swarming motility of APEC, and its ability to form biofilms. The significance of this finding is that the use of PD-rich CTs to control APEC should not encourage the development of antibiotic resistance by APEC because a different mechanism is used. If confirmed in vivo, this could provide the poultry industry with a valuable and novel means of controlling the antibiotic resistance. AbstractCondensed tannins (CTs), which extracted from yew leaves, tilia flower and black locust leaves, were examined for their antimicrobial in vitro activity against avian pathogenic Escherichia coli (APEC). Past research demonstrated that CTs which contain procyanidins and prodelphinidins that could inhibit the growth of a wide range of bacteria. However, there is no information on how these affect pathogenic bacteria from chickens such as APEC. The high concentration of extracts, 10, 5, 2Á5 mg ml À1 , affected the growth curves of APEC, which gave different inhibition values for the three CT extracts. Furthermore, these CTs had significant effects (P ≤ 0Á05) on APEC biofilm and motility depending on each CT concentration and composition. However, at low concentration (0Á6 mg ml À1 ), the tilia flowers, a high molar percentage of procyanidins, enhanced bacterial cell attachment and improved the swimming motility of APEC. In contrast, yew, an equal molar percentage of procyanidins/ prodelphinidins, and black locust, a high molar percentage of prodelphinidins, interrupted and blocked swarming and swimming motility. The data suggested that the antimicrobial activity of the CT extracts was elicited by a positive relationship between anti-biofilm formation and anti-motility capacities.

No abstract

This review surveys the nutritional and veterinary effects of tannins on ruminants and provides comparisons with non-ruminants. Tannins are a diverse group of naturally occurring compounds with useful biological effects. However, currently there are difficulties in predicting which tannins produce what effects.

Two-photon excitation enabled for the first time the observation and measurement of excited state fluorescence lifetimes from three flavanols in solution, which were ~ 1.0 ns for catechin and epicatechin, but <45 ps for epigallocatechin gallate (EGCG). The shorter