Corrole and Porphyrin Amino Acid Conjugates: Synthesis and Physicochemical Properties

A series of conjugates of amino acids with porphyrins and corroles was synthesized. Their self‐assembling ability under defined conditions was investigated by scanning electron microscopy. The morphology and photophysical properties of these molecules were studied by absorption and fluorescence spectroscopy in solid, liquid, and self‐assembled forms. We observed that both corrole and porphyrin conjugated with the l ‐phenylalanine–l ‐phenylalanine peptide to form spherical nanostructures with bathochromic shifts in the emission spectra, indicating the formation of aggregates. These aggregates are characterized by the impressive absorption of light over nearly the whole visible range. The broadening of all bands was particularly strong in the case of corroles. The fluorescence lifetimes of self‐assembled species were longer as compared to the solid‐state form.     

Preparation and characterization of polymer layer systems for validation of 3D Micro X-ray fluorescence spectroscopy

For the validation of the quantification of the newly-developed method of 3D Micro X-ray fluorescence spectroscopy (3D Micro-XRF) samples with a low average Z matrix and minor high Z elements are best suited. In a light matrix the interferences by matrix effects are minimized so that organic polymers are appropriate as basis for analytes which are more easily detected by X-ray fluorescence spectroscopy.     

Determination of antimicrobial activity and resistance to oxidation of moringa peregrina seed oil

The antimicrobial activity of the oil extracted with n-hexane from the seeds of Moringa peregrina was tested against Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Candida albicans, C. tropicalis and C. glabrata. The oil proved effective against all of the tested microorganisms. Standard antibiotics (netilmycin, 5-flucytocine, intraconazole and 7-amino-4-methylcoumarin-3-acetic acid) were used for comparison. The resistance to oxidation of the extracted seed oil was also determined.     

Genomics-Driven Discovery of a Novel Glutarimide Antibiotic from Burkholderia gladioli Reveals an Unusual Polyketide Synthase Chain Release Mechanism

A gene cluster encoding a cryptic trans-acyl transferase polyketide synthase (PKS) was identified in the genomes of Burkholderia gladioli BCC0238 and BCC1622, both isolated from the lungs of cystic fibrosis patients. Bioinfomatics analyses indicated the PKS assembles a novel member of the glutarimide class of antibiotics, hitherto only isolated from Streptomyces species. Screening of a range of growth parameters led to the identification of gladiostatin, the metabolic product of the PKS. NMR spectroscopic analysis revealed that gladiostatin, which has promising activity against several human cancer cell lines and inhibits tumor cell migration, contains an unusual 2-acyl-4-hydroxy-3-methylbutenolide in addition to the glutarimide pharmacophore. An AfsA-like domain at the C-terminus of the PKS was shown to catalyze condensation of 3-ketothioesters with dihydroxyacetone phosphate, thus indicating it plays a key role in polyketide chain release and butenolide formation.     

Comparative Study of a Series of 99mTc(CO)3 Mannosylated Dextran Derivatives for Sentinel Lymph Node Detection

Sentinel lymph node detection (SLND) is rapidly entering common practice in the management of patients with tumors. The introduction of mannose molecules to ^99mTc-labeled dextrans, so far, showed that the sentinel node could trap these agents due to their recognition by the mannose receptors of lymph node macrophages. The current study aimed to synthesize, characterize, and biologically evaluate a series of mannosylated dextran derivatives labeled with ^99mTc for potential use in SLND. The compounds were designed to have a dextran with a molecular weight of 10–500 kDa as a backbone, S-derivatized cysteines, efficient SNO chelators, and mannose moieties for binding to mannose receptors. They were successfully synthesized, thoroughly characterized using NMR techniques, and labeled with the fac-[^99mTc(CO)₃]⁺ synthon. Labeling with high yields and radiochemical purities was achieved with all derivatives. In vivo biodistribution and imaging studies demonstrated high uptake in the first lymph node and low uptakes in the following node and confirmed the ability to visualize the SLN. Among the compounds studied, ^99mTc-D75CM demonstrated the most attractive biological features, and in combination with the high radiochemical yield and stability of the compound, its further evaluation as a new radiopharmaceutical for sentinel lymph node detection was justified.     

Chemical Constituents from Croton insularis

Three new clerodane‐type terpenoids, furocrotinsulolide A ( 1 ), furocrotinsulolide B ( 2 ), and crotinsulactone ( 3 ), as well as a new phenolic disaccharide ( 4 ) have been isolated from the aerial parts of Croton insularis, together with eight known compounds. Their structures were established by in‐depth 1D‐ and 2D‐NMR spectroscopy, mass spectroscopy, and quantum‐mechanical calculations.     

Konstanz summer school 2018 on isotope ecology

Abstract

Biodegradation of polychlorinated biphenyls (PCBs) in soil is considered to be very complex due to various physico-chemical factors involved. Isotope labelling technique is the best to trace fate of the xenobiotic in the environment. In this work, the uniformly ¹⁴C-labelled PCB congener 11 (3,3′-chlorobiphenyl) was chosen as a low chlorinated coplanar biphenyl which was assumed to be readily degraded by microorganisms. Pleurotus ostreatus and two Pseudomonas species, representing white rot fungi and soil bacteria were used separately or in a consortium. The amount of liberated ¹⁴CO₂ and radio-HPLC, HPLC, GC-MS, and radio-TLC analyses of extracts at the end of a two-month experiment showed that the mineralization of PCB 11 was < 0.4%, volatilization < 3.1%, and 30% of radioactivity was irreversibly bound to the soil matrix. The respective contents of all intermediate metabolites were 4.7 to 10.5 and 2.5 to 2.7% where Pseudomonas alcaligenes alone or in combination with P. putida was applied. 3-Chlorobenzoic acid was the major biodegradation product.