Separation of phenotypically indistinguishable Candida species, C. orthopsilosis, C. metapsilosis and C. parapsilosis, by capillary electromigration techniques

At the current state of laboratory diagnostics, methods for fast identification of phenotypically indistinguishable species are difficult or inaccurate. An example is represented by Candida parapsilosis, which is the second most common yeast species isolated from bloodstream infections. C. parapsilosis comprises a complex of three genetically distinct groups. Genotypes II and III have been designated as the separate species Candida orthopsilosis and Candida metapsilosis, phenotypically indistinguishable. The considerable genetic variability of these newly described yeasts species has caused difficulties in the development of molecular techniques for their precise identification. Similarly, the detection of biofilm formation, which is considered as an important yeast virulence factor, is accompanied by difficulties. In this study we optimize the first precise and reproducible method for the separation and possible identification of C. orthopsilosis, C. metapsilosis and C. parapsilosis as well as the detection of their ability to form biofilm. The method is based on capillary isoelectric focusing and capillary electrophoresis with UV detection. In capillary isoelectric focusing, very narrow pH gradients were established. With such gradients, differences in isoelectric points of biofilm-negative and biofilm-positive species calculated from the migration times of the selected pI markers were below 0.03 pI units. In the capillary zone electrophoresis narrow zones of the cells of Candida species were detected with sufficient resolution. The values of the isoelectric point and the migration velocities of the examined species were independent on the origin of the tested strains. Capillary isoelectric focusing was examined also for the separation and detection of the cultivated biofilm-negative C. parapsilosis in the blood serum.     

R.A. Kishore,A. Martin,C. Wu,A. Kumar,S. Priya: Energy harvesting

Journal of Solid State Electrochemistry -     

Substitutionsprodukte des Cyclopentadiens, 6. Mitt.: C2-substituierte Cyclopentadiene

Zusammenfassung Aus Cyclopentadienmagnesiumbromid und Diäthylsulfat läßt sich unter milden Versuchsbedingungen ein Äthylcyclopentadienpräparat (I a) herstellen, das — im Gegensatz zu I-Präparaten anderer Herkunft³ — verhältnismäßig einheitlich reagiert. Das aus I a synthetisierte Maleinsäureanhydridaddukt erwies sich als 3-Äthyl-3, 6-methylen-1, 2, 3, 6-tetrahydrophthal-säureanhydrid (II a).Die Konstitution der aus Cyclopentadien-Na und 1,2-Dibromäthan synthetisierten Kohlenwasserstoffe (C₇H₈)_n konnte weiter gestützt werden: Monomeres und Dimeres des 5, 5-disubstituierten Cyclopentadiens Spiro[4,2]-heptadien-(2,4) (III a). Sowohl aus I als auch aus III a läßt sich 1, 1-Diäthyl-ferrocen erhalten.Mit 1 Abbildung5.Mitt., Mh. Chem.91, 805 (1960); 8 Mitt., Mh. Chem.91, 824 (1960).     

Bacterial carotenoids, XLVI. C50-Carotenoids, 14. C50-Carotenoids from Arthrobacter glacialis.

From the psychrophilic bacterium Arthrobacter glacialis have been isolated three C50-carotenoids with molecular formulae C50H72O2: the bicyclic decaprenoxanthin (1a, 7% of total carotenoids), the aliphatic bisanhydrobacterioruberin (2a, 10%) and the monocyclic A.g. 470 (3a, 83%). Decaprenoxanthin (1) and bisanhydrobacterioruberin (2) were in all respects, including chiroptical properties, identical with known carotenoids. The constitution of the previously undescribed A.g. 470 (3a) followed from its spectral properties (electronic, 1H NMR including Eu-shift experiments and mass spectra) and derivatization to 3b and 3c. 3a suffered remarkable elimination to the tridecaene 4a (C47H64O) upon DMSO/KOMe/MeOH treatment. Judged by CD data A.g. 470 (3a) also in stereochemical respect 3a appears to be half decaprenoxanthin (1a)+half bisanhydrobacterioruberin (2a). The intensity ratios of the M-92/M-106 ions on electron impact of 3a,b,c and 4a,b are consistent with the general theory.