Tracking yeast metabolism and the Crabtree effect in real time via CO2 production using Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS)

In this study, a new approach to measure metabolic activity of yeast via the Crabtree effect is described. BARDS is an analytical technique developed to aid powder and tablet characterisation by monitoring changes in the compressibility of a solvent during solute dissolution. It is a rapid and simple method which utilises a magnetic stir bar to mix added solute and induce the acoustic resonance of a vessel containing a fixed volume of solvent. In this study it is shown that initiation of fermentation in a yeast suspension, in aqueous buffer, is accompanied by reproducible changes in the frequency of induced acoustic resonance. These changes signify increased com-pressibility of the suspension due to CO2release by the yeast. A simple standardised BARDS protocol reveals yeast carbon source preferences and can generate quantitative kinetic data on carbon source metabolism which are characteristic of each yeast strain. The Crawford-Woods equation can be used to quantify total gaseous CO2produced by a given number of viable yeast when supplied with a fixed amount of carbon source. This allows for a value to be calculated for the amount of gaseous CO2produced by each yeast cell. The approach has the potential to transform the way in which yeast metabolism is tracked and potentially provide an orthogonal or surrogate method to determining viability, vitality and attenuation measurements in the future

Development of low-dose protocols for thin-section CT assessment of cystic fibrosis in pediatric patients.

Purpose: To develop low-dose thin-section computed tomographic (CT) protocols for assessment of cystic fibrosis (CF) in pediatric patients and determine the clinical usefulness thereof compared with chest radiography. Materials and Methods: After institutional review board approval and informed consent from patients or guardians were obtained, 14 patients with CF and 11 patients without CF (16 male, nine female; mean age, 12.6 years ± 5.4 [standard deviation]; range, 3.5–25 years) who underwent imaging for clinical reasons underwent low-dose thin-section CT. Sections 1 mm thick (protocol A) were used in 10 patients, and sections 0.5 mm thick (protocol B) were used in 15 patients at six levels at 120 kVp and 30–50 mA. Image quality and diagnostic acceptability were scored qualitatively and quantitatively by two radiologists who also quantified disease severity at thin-section CT and chest radiography. Effective doses were calculated by using a CT dosimetry calculator. Results: Low-dose thin-section CT was performed with mean effective doses of 0.19 mSv ± 0.03 for protocol A and 0.14 mSv ± 0.04 for protocol B (P < .005). Diagnostic acceptability and depiction of bronchovascular structures at lung window settings were graded as almost excellent for both protocols, but protocol B was inferior to protocol A for mediastinal assessment (P < .02). Patients with CF had moderate lung disease with a mean Bhalla score of 9.2 ± 5.3 (range, 0–19), compared with that of patients without CF (1.1 ± 1.4; P < .001). There was excellent correlation between thin-section CT and chest radiography (r = 0.88–0.92; P < .001). Conclusion: Low-dose thin-section CT can be performed at lower effective doses than can standard CT, approaching those of chest radiography. Low-dose thin-section CT could be appropriate for evaluating bronchiectasis in pediatric patients, yielding appropriate information about lung parenchyma and bronchovascular structures

High-resolution structure of the antibiotic resistance protein NimA from Deinococcus radiodurans

In this paper, the 1.2 Å atomic resolution crystal structure of the 5-nitroimidazole antibiotic resistance protein NimA from Deinococcus radiodurans (DrNimA) is presented