Venom peptides cathelicidin and lycotoxin cause strong inhibition of Escherichia coli ATP synthase.

Venom peptides are known to have strong antimicrobial activity and anticancer properties. King cobra cathelicidin or OH-CATH (KF-34), banded krait cathelicidin (BF-30), wolf spider lycotoxin I (IL-25), and wolf spider lycotoxin II (KE-27) venom peptides were found to strongly inhibit Escherichia coli membrane bound F1Fo ATP synthase. The potent inhibition of wild-type E. coli in comparison to the partial inhibition of null E. coli by KF-34, BF-30, Il-25, or KE-27 clearly links the bactericidal properties of these venom peptides to the binding and inhibition of ATP synthase along with the possibility of other inhibitory targets. The four venom peptides KF-34, BF-30, IL-25, and KE-27, caused ≥85% inhibition of wild-type membrane bound E.coli ATP synthase. Venom peptide induced inhibition of ATP synthase and the strong abrogation of wild-type E. coli cell growth in the presence of venom peptides demonstrates that ATP synthase is a potent membrane bound molecular target for venom peptides. Furthermore, the process of inhibition was found to be fully reversible.

Ozonation of carbamazepine in drinking water: identification and kinetic study of major oxidation products.

Kinetics and product formation of the anti-epileptic drug carbamazepine (CBZ) were investigated in lab-scale experiments during reactions with ozone and OH radicals. Ozone reacts rapidly with the double bond in CBZ, yielding several ozonation products containing quinazoline-based functional groups. The structures for three new oxidation products were elucidated using a combination of mass spectrometric and NMR techniques. The three products were determined to be 1-(2-benzaldehyde)-4-hydro-(1H,3H)-quinazoline-2-one (BQM), 1-(2-benzaldehyde)-(1H,3H)-quinazoline-2,4-dione (BQD), and 1-(2-benzoic acid)-(1H,3H)-quinazoline-2,4-dione (BaQD). Additional kinetic studies of the ozonation products showed very slow subsequent oxidation kinetics with ozone (second-order rate constants, kO3 = approximately 7 M(-1)s(-1) and approximately 1 M(-1)s(-1) at pH = 6 for BQM and BQD, respectively). Rate constants for reactions with OH radicals, kOH, were determined as approximately 7 x 10(9) M(-1)s(-1) for BQM and approximately 5 x 10(9)M(-1)s(-1) for BQD. Thus, mainly reactions with OH radicals lead to their further oxidation. A kinetic model including ozone and OH radical reactions allows a prediction of the time-dependent product distribution during ozonation of natural waters. In Rhine River water, CBZ spiked at 500 ng/L was completely oxidized by ozone with applied doses > or =0.3 mg/L. To confirm that the two major ozonation products BQM and BQD are produced as a result of the ozonation of a CBZ-containing natural water, Lake Zurich water samples were spiked with CBZ (1 microM, 236 microg/L). The oxidation products were identified via LC-UV. Concentrations of 0.48 and 0.15 microM for BQM and BQD, respectively, were measured for an ozone dose of 1.9 mg/L. BQM and BQD were also identified in ozonated water from a German waterworks containing CBZ in its raw water with 0.07-0.20 microg/L. Currently, there are no data available on the biological effects of the formed oxidation products.

Ozonation: a tool for removal of pharmaceuticals, contrast media and musk fragrances from wastewater?

A pilot plant for ozonation and UV-disinfection received effluent from a German municipal sewage treatment plant (STP) to test the removal of pharmaceuticals, iodinated X-ray contrast media (ICM) and musk fragrances from municipal wastewater. In the original STP effluent, 5 antibiotics (0.34-0.63 microgl(-1)), 5 betablockers (0.18-1.7 microgl(-1)), 4 antiphlogistics (0.10-1.3 microgl(-1)), 2 lipid regulator metabolites (0.12-0.13 microgl(-1)), the antiepileptic drug carbamazepine (2.1 microgl(-1)), 4 ICM (1.1-5.2 microgl(-1)), the natural estrogen estrone (0.015 microgl(-1)) and 2 musk fragrances (0.1-0.73 microgl(-1)) were detected by LC-electrospray tandem MS and/or GC/MS/MS. ICM, derived from radiological examinations, were present with the highest concentrations (diatrizoate: 5.7 microgl(-1), iopromide: 5.2 microgl(-1)). By applying 10-15 mgl(-1) ozone (contact time: 18 min), all the pharmaceuticals investigated as well as musk fragrances (HHCB, AHTN) and estrone were no longer detected. However, ICM (diatrizoate, iopamidol, iopromide and iomeprol) were still detected in appreciable concentrations. Even with a 15 mgl(-1) ozone dose, the ionic diatrizoate only exhibited removal efficiencies of not higher than 14%, while the non-ionic ICM were removed to a degree of higher than 80%. Advanced oxidation processes (O(3)/UV-low pressure mercury arc, O(3)/H(2)O(2)), which were non-optimized for wastewater treatment, did not lead significantly to a higher removal efficiency for the ICM than ozone alone.

Removal of pharmaceuticals during drinking water treatment.

The elimination of selected pharmaceuticals (bezafibrate, clofibric acid, carbamazepine, diclofenac) during drinking water treatment processes was investigated at lab and pilot scale and in real waterworks. No significant removal of pharmaceuticals was observed in batch experiments with sand under natural aerobic and anoxic conditions, thus indicating low sorption properties and high persistence with nonadapted microorganisms. These results were underscored by the presence of carbamazepine in bank-filtrated water with anaerobic conditions in a waterworks area. Flocculation using iron(III) chloride in lab-scale experiments (Jar test) and investigations in waterworks exhibited no significant elimination of the selected target pharmaceuticals. However, ozonation was in some cases very effective in eliminating these polar compounds. In lab-scale experiments, 0.5 mg/L ozone was shown to reduce the concentrations of diclofenac and carbamazepine by more than 90%, while bezafibrate was eliminated by 50% with a 1.5 mg/L ozone dose. Clofibric acid was stable even at 3 mg/L ozone. Under waterworks conditions, similar removal efficiencies were observed. In addition to ozonation, filtration with granular activated carbon (GAC) was very effective in removing pharmaceuticals. Except for clofibric acid, GAC in pilot-scale experiments and waterworks provided a major elimination of the pharmaceuticals under investigation.