Eighteen yeast species of the genera Rhodotorula , Rhodosporidium , Sporobolomyces , and Sporidiobolus , each one represented by its type strain, were investigated with the objective of evaluating their carotenoid composition. The pigments were extracted from yeast cells, quantified by high pressure liquid chromatography diode array detector and the main compounds were confirmed by atmospheric pressure chemical ionization quadrupole mass spectrometry. Significant (P < 0.01) differences among several species and (or) genera were observed. Thirteen strains were seen to be able to produce carotenoids, from 16.4 to 184 μg/g cell dry mass and from 6.0 to 1993.4 μg/L culture. The main carotenoids produced were identified as torularhodin, torulene, γ-carotene, and β-carotene. The correlation matrix calculated on the basis of the carotenoid composition data matrix indicated significant (P < 0.01) relationships between torulene and torularhodin (r = 0.81), γ-carotene and torulene (r = 0.49), β-carotene and torulene (r = –0.72), as well as β-carotene and γ-carotene (r = 0.64). These significant correlation coefficients may suggest that species belonging to the genera Rhodosporidium, Sporobolomyces, and Sporidiobolus possess a carotenoid biosynthetic pathway analogous to that elsewhere postulated for Rhodotorula species.

Background: The expansion of newborn screening programs has increased the number of newborns diagnosed with inborn errors of metabolism in the presymptomatic phase, but it has also increased the number of costly, stress-producing false-positive results. Because propionylcarnitine (C3) is one of the analytes most frequently responsible for false-positive results, we aimed to develop a rapid liquid chromatography–tandem mass spectrometry (LC-MS/MS) method to identify free methylmalonic (MMA) and 3-OH propionic (3OH-PA) acids in blood spots.Methods: We studied newborn screening spots from 250 healthy controls; 124 from infants with abnormal C3, of whom only 5 (4%) were truly affected; 124 from infants with altered isolated methylmalonylcarnitine; and 4 from clinically diagnosed patients. Whole blood was eluted from a 3.2-mm dried blood spot by a CH3CN/H2O 7:3 and 5 mL/L formic. This extract was injected into a LC-MS/MS equipped with pneumatically assisted electrospray without derivatization. Total analysis time was 5 min per sample.Results: The assays were linear up to 3300 nmol/L for both metabolites. Intra- and interassay imprecision data were 3.6%–8% and 3.1%–6%, respectively, for MMA and 5.2%–20% and 3.6%–17% for 3OH-PA. Limit of detection and limit of quantitation were 1.95 and 4.2 μmol/L, respectively, for MMA and 8 and 10 μmol/L for 3OH-PA. The recoveries were 92.9%–106.1%. No deterioration was noted on the columns after 500 chromatographic runs. If the new method had been used as a 2nd-tier test for the 124 samples, only the 5 true positives would have been recalled for additional samples, and the positive predictive value would have been 100%.Conclusions: This method has the potential to markedly reduce false-positive results and the associated costs and anxiety. It may also be suitable for diagnosing and routinely monitoring blood spots for methylmalonic aciduria and propionic acidemia.