Evaluation of extraction processes for intracellular metabolite profiling of mammalian cells: matching extraction approaches to cell type and metabolite targets

In this study we report on the optimisation of the technologies for generation of a global metabolomics profile for intracellular metabolites in Chinese hamster ovary (CHO) cells. We evaluated the effectiveness of a range of different extraction methods applied to CHO cells which had been quenched using a previously optimised approach. The extraction methods tested included cold methanol, hot ethanol, acid, alkali and methanol/chloroform plus combinations of these. The extraction of metabolites using two 100% methanol extractions followed by a final water extraction recovered the largest range of metabolites. For the majority of metabolites, extracts generated in this manner exhibited the greatest recovery with high reproducibility. Therefore, this was the best extraction method for attaining a global metabolic profile from a single sample. However, another parallel extraction method (e.g. alkali) may also be required to maximise the range of metabolites recovered (e.g. non-polar metabolites).     

Destruction of Bacillus anthracis strain Sterne 34F2 spores in postal envelopes by exposure to electron beam irradiation

AIMS: To determine the irradiation dose necessary to reduce the populations of Bacillus anthracis spores in a dry medium in postal envelopes. METHODS AND RESULTS: Bacillus anthracis Sterne 34F2 spores were dispersed in non-fat dry milk and then placed into standard business postal envelopes. The spores were treated with a sequence of irradiation doses to determine the decimal reduction value (D10) in kiloGrays (kGy). The average D10 value was 3.35 +/- 0.02 kGy. CONCLUSIONS: An irradiation dose of 40.2 kGy would be required to result in a process equivalent to the thermal canning process (12 D10 reduction) to eliminate Clostridium botulinum spores. SIGNIFICANCE AND IMPACT OF THE STUDY: Irradiation is an effective means of reducing or eliminating B. anthracis spores in a dry medium in postal envelopes.     

Interacting elevated CO2 and tropospheric O3 predisposes aspen (Populus tremuloides Michx.) to infection by rust (Melampsora medusae f. sp. tremuloidae)

We investigated the interaction of elevated CO₂ and/or (Ozone) O₃ on the occurrence and severity of aspen leaf rust (Melampsora medusae Thuem. f. sp. tremuloidae) on trembling aspen (Populus tremuloides Michx.). Furthermore, we examined the role of changes in leaf surface properties induced by elevated CO₂ and/or O₃ in this host–pathogen interaction. Three‐ to five‐fold increases in levels of rust infection index were found in 2 consecutive years following growing‐season‐long exposures with either O₃ alone or CO₂ + O₃ depending on aspen clone. Examination of leaf surface properties (wax appearance, wax amount, wax chemical composition, leaf surface and wettability) suggested significant effects by O₃ and CO₂ + O₃. We conclude that elevated O₃ is altering aspen leaf surfaces in such a way that it is likely predisposing the plants to increased infection by aspen leaf rust.