Altered flavin patterns in photobehavioral mutants of Phycomyces blakesleeanus.

Flavins were extracted from sporangiophores of the lower fungus Phycomyces blakesleeanus and identified by HPLC with fluorescence detection. In the wild-type strain NRRL1555 they were found to be present at the following concentrations: riboflavin (5.5 x 10(-6) M), flavin mononucleotide (FMN) (4.0 x 10(-6) M) and flavin adenine dinucleotide (1.4 x 10(-6) M). The HPLC elution profiles of the wild type were compared to a set of behavioral mutants (genotype mad) with specific defects in their light-transduction pathway. The photoreceptor mutants C109 (madB), C111 (madB) and L1 (madC) had normal amounts of flavins. The most prominent changes were found in single mutants with a defective madA gene which contained about 25% of riboflavin and about 10% of FMN and FAD normally found in the wild type. A hypertropic mutant with a defective madH gene contained instead 80% of riboflavin and 120% of FMN and FAD. The double mutant L52 (madA madC) and the triple mutant L72 (madA madB madC) had normal amounts of FAD and FMN. This indicates that the madC mutation, which itself causes loss of light sensitivity and which affects the near-UV/blue-light receptor (Galland and Lipson, 1985, Photochem. Photobiol. 41, 331-335) functions as a restorer of the flavin content in a genetic madA background. The double mutant L51 (madA madB) had about 40% of FMN and FAD, suggesting that the madB mutation functions as a partial restorer of flavin content. The photogravitropic thresholds (450 nm) reported for the wild type and the madA and madH mutants were positively correlated to the endogeneous concentrations of FMN and FAD.(ABSTRACT TRUNCATED AT 250 WORDS)     

Trace analysis of chlorofluorocarbons/partially halogenated chlorofluorohydrocarbons (CFC/HCFC) in polymeric foams by headspace capillary gas chromatography with electron-capture detection or ion trap detection combined with preconcentration on a cold trap

Two headspace-methods were developed for the detection and determination of traces of CFC/HCFC in polymeric foams. These methods consist of capillary gas chromatography using an electron-capture detector (ECD method) or an ion trap detector combined with preconcentration on a cold trap (ITD method). Different CFC/HCFC such as R115, R22, R12, R142b, R114, R11, R141b and R113 were investigated in polyethylene and flexible polyurethane foams. Conditions for sample preparation (e.g. thermostating time and temperature) were optimized. Determination of the detection limits and quantitation of the amount of CFC/HCFC released from the foam were performed with gas standards prepared with the help of mass flow controllers. Quantitative analyses of the total amount of CFC/HCFC present in the foam were performed using multiple headspace extraction. Longterm studies were performed on the rate of release of some CFC/HCFC from the foams. Additionally a method for distinguishing a CFC/HCFC-contaminated foam from an old CFC/HCFC-blown foam is presented. Both methods can be used individually; however, best results are achieved by using the ECD method for screening and the ITD method for confirmation. This combination was used for routine analysis enforcing legal restrictions on the use of CFC/HCFC in foams.Abbreviations CFC chlorofluorocarbon - HCFC partially halogenated chlorofluorohydrocarbon - PUR polyurethane - PS polystyrene - PE polyethylene - MHE multiple headspace extraction - ECD electron capture detector - ITD ion trap detector - FID flame ionization detector - TCD thermal conductivity detector - MS mass spectrometry - WCOT wall coated, open tubular (column) - ppm parts per million (1:10⁶ v/v) - ppb parts per billion (1:10⁹ v/v) - ppt parts per trillion (1:10¹² v/v) - DL detection limit - RSD relative standard deviation - CO₂ carbon dioxide - R115 C₂ClF₅ - R22 CHClF₂ - R12 CCl₂F₂ - R142b C₂H₃ClF₂ - R114 C₂Cl₂F₄ - R11 CCl₃F - R141b C₂H₃ClF - R113 C₂Cl₃F₃