Publications by authors named "Stanislav Pospisil"

Purpose: In carbon ion beam radiation therapy, fragmentation processes within the patient lead to changes in the composition of the particle field with increasing depth. Consequences are alterations of the resulting dose distribution and its biological effectiveness. To enable accurate treatment planning, the characteristics of the ion spectra resulting from fragmentation processes need to be known for various ion energies and target materials.

View Article and Find Full Text PDF
Article Synopsis
  • A combined approach of PCR screening and genome mining was employed to explore the diversity and evolutionary relationships of genes responsible for 5-aminolevulinic acid synthases (ALASs) in strains related to streptomycetes.
  • These ALASs are linked to producing secondary metabolites with potential medical and agricultural applications, specifically those containing the C5N unit.
  • The study identified 226 hemA gene-carrying strains, revealing a high percentage of them encoding a specialized form called cyclizing ALAS (cALAS), which facilitates unique chemical processes, along with evidence of horizontal gene transfer among actinomycetes and other organisms.
View Article and Find Full Text PDF

Monensin A is a commercially important natural product isolated from Streptomyces cinnamonensins that is primarily employed to treat coccidiosis. Monensin A selectively complexes and transports sodium cations across lipid membranes and displays a variety of biological properties. In this study, we evaluated the Jacobsen catalyst as a cytochrome P450 biomimetic model to investigate the oxidation of monensin A.

View Article and Find Full Text PDF

Colabomycin E is a new member of the manumycin-type metabolites produced by the strain Streptomyces aureus SOK1/5-04 and identified by genetic screening from a library of streptomycete strains. The structures of colabomycin E and accompanying congeners were resolved. The entire biosynthetic gene cluster was cloned and expressed in Streptomyces lividans.

View Article and Find Full Text PDF

1. Monensin A, an important antibiotic ionophore that is primarily employed to treat coccidiosis, selectively complexes and transports sodium cations across lipid membranes and displays a variety of biological properties. 2.

View Article and Find Full Text PDF
Article Synopsis
  • Asukamycin, an antimicrobial and potential antitumor agent, is isolated from Streptomyces nodosus and its biosynthetic gene cluster has been successfully cloned and expressed in Streptomyces lividans.
  • The biosynthetic pathway involves multiple genes (asuA-D) that contribute to the formation of key building blocks, leading to the creation of the intermediate protoasukamycin and its conversion to the final product through specific enzymes.
  • Branched acyl CoA units from amino acids Val, Leu, and Ile are utilized in the production of asukamycin variants, while a type II thioesterase helps regulate cellular fatty acid levels and membrane stability.
View Article and Find Full Text PDF

Two new carbasugars (9 and 10) were isolated from Streptomyces lincolnensis DSM 40355 along with streptol (valienol, 8), gabosine I (valienone, 14), and glucosylglycerate. The reported (1)H and (13)C assignments are based on 1D ((1)H, (13)C, 1D-TOCSY, homodecoupling) and 2D (gCOSY, J-resolved, TOCSY, ROESY, gHSQC, gHMBC) NMR techniques and electrospray ionization FT mass spectrometry (ESI FTMS).

View Article and Find Full Text PDF

The biosynthetic pathway of the clinically important antibiotic lincomycin is not known in details. The precise knowledge of the lincomycin biosynthesis is a prerequisite for generation of improved derivatives by means of combinatorial genetics. Methods allowing determination of the key intermediates are very important tools of the pathway investigation.

View Article and Find Full Text PDF

A method has been developed for routine laboratory visualisation of small-scale soft tissue by means of transmission X-ray radioscopy and tomography. Using termites as models, imaging quality with a spatial resolution of about 3 mum was achieved and 3D tomographic reconstruction was demonstrated. A termite worker individual was visualized before and after its metamorphosis towards the soldier caste.

View Article and Find Full Text PDF

A new ribose trisaccharide, alpha-Ribf-(1-->2)-alpha-Ribf-(1-->3)-alpha-Ribf (1), was isolated together with 5-O-(alpha-mannosyl)-myo-inositol (2), 2-O-(alpha-mannosyl)-myo-inositol (3), trehalose (4), and d-ribulose (5) from a submerged cultivation of Streptomyces coelicolor A3(2). The structures of these compounds were elucidated by spectroscopic and chemical methods. Concentrations of these compounds in the medium were in the range from 0.

View Article and Find Full Text PDF