Fusarium culmorum produces polyketide-structured aurofusarin and its precursor metabolites. Aurofusarin biosynthetic pathway is catalysed by the products of eleven genes located in gene cluster. In this study, the effects of the expression levels of Pks12, Gip6, and Gip7, responsible genes for the intracellular steps of the pathway, on pigmentation were investigated in an F. culmorum field isolate. Presence of three genes were determined via PCR and sequencing. Their expressions were investigated by qPCR at 48 th , 72 nd , 120 th and 168 th hours. Aurofusarin and rubrofusarin production were verified by HPLC at the same time periods. Mycelial pigmentation, which was initially white, turned yellow, then carmine red during the sevenday culture. Pks12, Gip6, Gip7 genes with 1282, 449 and 1278 bps had sequence similarities (86,6%, 99,4% and 80,5% respectively) with the genes of reference (FcUK99). The ΣCp values of all genes ranged from 29th to 32nd cycles, whereas the ΣΔΔCt values were calculated between 9,59 E-02 and 1,30 E-02. Relative quantification revealed these genes were controlled by down-regulation compared to the β-tubulin expression. Aurofusarin quantities ranged from 2,355 ppm to 27,350 ppm between the 72 nd and 168 th hours whereas the yield of rubrofusarin decreased from 0,098 ppm to 0,063 ppm. ( 4) Conclusion: This study becomes first report for both investigating the expression levels of the genes responsible for the catalysis of intracellular steps of aurofusarin biosynthesis in F. culmorum, and for examining the relationship between gene expression and mycelium pigmentation. HIGHLIGHTS• Molecular analysis of aurofusarin biosynthesis in F. culmorum.• Mycelial pigmentation depending on gene expression and aurofusarin accumulation.• Pigmentation variations depending on growth phase.

This study presents the use of disposable pencil graphite electrode to investigate the electrochemical behaviors and voltammetric determination of cephalexin and cefazolin in phosphate buffer at different pH values (4.5-6.0). Sample analysis was performed in phosphate buffer at the optimum medium determined for each sample. Validation parameters were studied to show the correctness, sensitivity, and consistency of the method developed for the cephalosporins. It was concluded that disposable pencil graphite electrode could be used effectively in the determination of cephalosporins. The limits of detection (LOD) (S/N=3) were found to be 0.117 mM and 0.293 mM, for cephalexin and cefazolin, respectively. The analysis of these compounds in pharmaceutical formulations and in human blood serum and urine samples was carried out at defined optimum conditions.

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In this study, a reverse-phase high performance liquid chromatography (RP-HPLC) method with high separation efficiency, high detection sensitivity and excellent selectivity was successfully developed for the simultaneous determination of the aloe-emodin, rhein, emodin, chrysophanol, and physcion compounds. These optimum method conditions were determined by studying various columns, mobile phases and compositions, flow rates and column temperatures. The successful separation was carried out with a Supelcosil LC-18 column (250 × 4.6 mm, 5 µm) and a gradient program. The procedure was carried out at 20 °C with the flow rate of 1.0 mL/min. and the injection volume of 20 μL utilizing an RP-HPLC method with DAD detector at 225 nm. Deionized water containing 0.5% (v/v) orthophosphoric acid and methanol was used as the mobile phases A and B. This study showed an optimized analytical method can be effectively utilized to the qualitative determination of anthraquinone compounds.