Differences in resting metabolic rates of two southern African tortoises: Psammobates oculiferus and Geochelone pardalis

Energy metabolism varies considerably between different groups of endotherms, yet there is little or no reported variation among extant groups of reptiles. We measured lower resting metabolic rates (RMRs) in Kalahari tent tortoises (Psammobate oculiferus) than in sympatric Leopard tortoises (Geochelone pardalis). G pardalis also had RMR values that were higher than the allometric prediction for reptiles whereas P oculiferus had RMR values that were not significantly different from the prediction. Differences in RMR between the two species may have occurred because of the large differences in body mass, differing body temperatures, differences in growth rates, or because there may have been differences in the heat increment of feeding.

Identifying the influence of geology, land use, and anthropogenic activities on riverine sulfate on a watershed scale by combining hydrometric, chemical and isotopic approaches

Throughout the last few decades, sulfate concentrations in streamwater have received considerable attention due to their dominant role in anthropogenic acidification of surface waters. The objectives of this study conducted in the Oldman River Basin in Alberta (Canada) were to determine the influence of geology, land use and anthropogenic activities on sources, concentrations and fluxes of riverine sulfate on a watershed scale. This was achieved by combining hydrological, chemical and isotopic techniques. Surface water samples were collected from the main stem and tributaries of the Oldman River on a monthly basis between December 2000 and March 2003 and analyzed for chemical and isotopic compositions. At a given sampling site, sulfate sources were primarily dependent on geology and did not vary with time or flow condition. With increasing flow distance a gradual shift from ?34S values > 10 ‰ and ?18O values > 0 ‰ of riverine sulfate indicating evaporite dissolution and soil-derived sulfate in the predominantly forested headwaters, to negative ?34S and ?18O values suggested that sulfide oxidation was the predominant sulfate source in the agriculturally used downstream part of the watershed. Significant increases in sulfate concentrations and fluxes with downstream distance were observed, and were attributed to anthropogenically enhanced sulfide oxidation due to the presence of an extensive irrigation drainage network with seasonally varying water levels. Sulfate-S exports in an artificially drained subbasin (64 kg S/ha/yr) were found to exceed those in a naturally drained subbasin (4 kg S/ha/yr) by an order of magnitude. Our dataset suggests that the naturally occurring process of sulfide oxidation has been enhanced in the Oldman River Basin by the presence of an extensive network of drainage and irrigation canals.

Antibacterial activities of naturally occurring compounds against Mycobacterium avium subsp. paratuberculosis.

The antibacterial activities of 18 naturally occurring compounds (including essential oils and some of their isolated constituents, apple and green tea polyphenols, and other plant extracts) against three strains of Mycobacterium avium subsp. paratuberculosis (a bovine isolate [NCTC 8578], a raw-milk isolate [806R], and a human isolate [ATCC 43015]) were evaluated using a macrobroth susceptibility testing method. M. avium subsp. paratuberculosis was grown in 4 ml Middlebrook 7H9 broth containing 10% oleic acid-albumin-dextrose-catalase, 0.05% Tween 80 (or 0.2% glycerol), and 2 µg/ml mycobactin J supplemented with five concentrations of each test compound. The changes in the optical densities of the cultures at 600 nm as a measure of CFU were recorded at intervals over an incubation period of 42 days at 37°C. Six of the compounds were found to inhibit the growth of M. avium subsp. paratuberculosis. The most effective compound was trans-cinnamaldehyde, with a MIC of 25.9 µg/ml, followed by cinnamon oil (26.2 µg/ml), oregano oil (68.2 µg/ml), carvacrol (72.2 µg/ml), 2,5-dihydroxybenzaldehyde (74 µg/ml), and 2-hydroxy-5-methoxybenzaldehyde (90.4 µg/ml). With the exception of carvacrol, a phenolic compound, three of the four most active compounds are aldehydes, suggesting that the structure of the phenolic group or the aldehyde group may be important to the antibacterial activity. No difference in compound activity was observed between the three M. avium subsp. paratuberculosis strains studied. Possible mechanisms of the antimicrobial effects are discussed.

Recent activities at the Tokyo EBIT 2006

The electron beam ion trap (EBIT) in Tokyo was constructed about 10 years after the first EBIT at Lawrence Livermore National Laboratory was built, and has been being stably operated since then. In this paper, we present recent experimental activities at the Tokyo EBIT. In particular, experiments utilizing slow, very highly charged ion beams extracted from the EBIT are reported.

Anti-adherent and antifungal activities of surfactant-coated poly (ethylcyanoacrylate) nanoparticles

Application of non-drug-loaded poly(ethylcyanoacrylate) nanoparticles (NP) to buccal epithelial cells (BEC) imparted both anti-adherent and antifungal effects. NP prepared using emulsion polymerisation and stabilised using cationic, anionic and non-ionic surfactants decreased Candida albicans blastospore adhesion, an effect attributable to the peripheral coating of surfactant. Cetrimide and Pluronic (R) P 123 were shown to be most effective, producing mean percentage reductions in blastospore adherence of 52.7 and 37.0, respectively. Resultant zeta potential matched the polarity of the surfactant, with those stabilised using cetrimide being especially positive (+31.3 mV). Preparation using anionic surfactants was shown to be problematic, with low yield and wide particle size distribution. Evaluation of the antifungal effect of the peripheral coat was evaluated using zones of inhibition and viable counts assays. The former test revealed poor surfactant diffusion through agar, but did show evidence of limited kill. However, the latter method showed that cationic surfactants associated with NP produced high levels of kill, in contrast to those coated with anionic surfactants, where kill was not evident. Non-ionic surfactant-coated NP produced intermediate kill rates. Results demonstrate that surfactant-coated NP, particularly the cationic types, form the possible basis of a prophylactic formulation that primes the candidal target (BEC) against fungal adhesion and infection. (c) 2007 Elsevier B.V. All rights reserved.

Effect of the metabolic inhibitor, methimazole on the drug susceptibility of a triclabendazole-resistant isolate of Fasciola hepatica

A study has been carried out to investigate whether the action of triclabendazole (TCBZ) is altered in the presence of a metabolic inhibitor. The flavin monooxygenase system (FMO) was inhibited using methimazole (MTZ) to see whether a TCBZ-resistant isolate could be made more sensitive to TCBZ action. The Oberon TCBZ-resistant and Cullompton TCBZ-sensitive isolates Were used for these experiments. The FMO system was inhibited by a 2-h pre-incubation in methimazole (100 mu M). Flukes were then incubated for I further 22 h in NCTC medium containing either MTZ; MTZ+nicotinamide adenine dinucleotide phosphate (NADPH) (1 nm); MTZ+NADPH+TCBZ (15 mu g/ml); or MTZ+NADPH+triclabendazole sulphoxide (TCBZ.SO) (15 mu g/ml). Morphological changes resulting from drug treatment and following metabolic inhibition were assessed Using scanning electron microscopy'. After treatment with either TCBZ or TCBZ.SO alone, there was greater surface disruption to the triclabendazole-susceptible than -resistant isolate. However, co-incubation with MTZ and TCBZ/TCBZ.SO lead to more severe surface changes to the TCBZ-resistant isolate than with each drug oil its own; this was not seen for the TCBZ-susceptible Cullompton isolate. Results of this study support the concept of altered drug metabolism in TCBZ-Resistant flukes and this process may play a role in the development of drug resistance.

Antibiofilm activities of 1-alkyl-3-methylimidazolium chloride ionic liquids

Microbial biofilms are ubiquitous in nature and represent the predominant mode of growth of microorganisms. A general characteristic of biofilm communities is that they tend to exhibit significant tolerance to antimicrobial challenge compared with planktonic bacteria of the same species The antibiofilm activity of a series of 1-alkyl-3-methylimidazolium chloride ionic liquids has been evaluated against a panel of clinically significant microbial pathogens, including MRSA. A comparison of antimicrobial activity against planktonic bacteria and established biofilms is presented. In general, these ionic liquids possess potent, broad spectrum antibiofilm activity.