Biomedical subjects
Publications and source records attributed to H Budzikiewicz.
The structures of the two fengycins, lipopeptides from Bacillus subtilis, were elucidated by spectroscopic methods and chemical degradation. They show a close structural relationship to the plipastatins from Bacillus cereus differing only in the stereochemistry of the Tyr residues.
The use of explosives as matrices, a principle used previously in plasma desorption mass spectrometry, was applied to fast atom bombardment mass spectrometry (FABMS). Ternary matrices were prepared by the addition of picric acid and related compounds to the binary matrix routinely used for the analysis of peptides, viz. thioglycerol-dithiodiethanol. With the new matrices, the spectra of three ferri-pyoverdins (iron-siderophore complexes which are often difficult to analyse by FABMS with standard matrices) showed a significant increase in both intensity and duration of the ion current. They present a valuable tool for the analysis of problematic analytes and for collision-induced dissociation MS/MS experiments.
OBJECTIVES: The purpose of our study was to determine the quality and quantity of leachable residual (co)monomers and additives eluted from various commercial dental composite resins after polymerization. METHODS: Polymerized specimens from four universal hybrid-type composite resins were eluted for 3 days with methanol resp, water. Then all extracts were analysed by gas chromatography/mass spectrometry or liquid chromatography/mass spectrometry using a particle beam interface. RESULTS: In all polymerized composite resin specimens, (co)monomers and various additives as well as contaminants from manufacturing processes were identified. Almost every compound detected in the unpolymerized resins could also be identified in the methanol extracts, but only a few of them were found in the water extracts. From these the co-monomer TEGDMA was extracted in quantities higher than those reported to be cytotoxic in primary human oral fibroblast cultures. CONCLUSIONS: From our results we conclude that the extractable quantities of composite resin components should be minimized, either by reducing the mobility of leachable substances within the set material or by applying less water-soluble components. Furthermore, all ingredients of a dental composite should be declared by the manufacturers, in order to identify those substances in a product which may cause adverse side effects in patients and dental personnel.
Two pyoverdin-ampicillin conjugates were synthesized and their structures were confirmed by mass spectrometry and NMR spectroscopy. In contrast to ampicillin, the conjugates exhibited high antibacterial activity against Pseudomonas aeruginosa ATCC 15692 and ATCC 27853, effective only against the strain which is using the parent pyoverdin for iron uptake. This suggests that the conjugates enter the bacterial cell via the ferripyoverdin uptake pathway. Growth stimulation studies with conjugates hydrolysed at the beta-lactam ring of the ampicillin moiety supported this view.
A strain of Acremonium luzulae (Fuckel) W. Gams was selected in screening new microorganisms for biological control of fruit postharvest diseases, especially gray and blue mold diseases on apples and strawberries. This strain manifests a very strong activity against a large number of phytopathogenic fungi. In this work, the product responsible for this antifungal activity was isolated from modified Sabouraud dextrose broth cultures of A. luzulae. It was purified to homogeneity by reverse-phase column chromatography. On the basis of UV, infrared, and 1H and 13C nuclear magnetic resonance spectra, mass spectral analysis, and the amino acid composition of the acid hydrolysates, the antibiotic was determined to be cyclosporin C. Cyclosporin C showed a broad-spectrum activity against filamentous phytopathogenic fungi but no activity against bacteria or yeasts. Its antifungal activity is only fungistatic. In contrast to Tolypocladium inflatum, another cyclosporin-producing strain, A. luzulae, did not produce additional cyclosporins. This was confirmed by in vivo-directed biosynthesis.
We describe a new genus of mesophilic actinomycetes, for which we propose the name Lentzea. The strains of this genus form abundant aerial hyphae that fragment into rod-shaped elements. Whole-cell hydrolysates contain the meso isomer of diaminopimelic acid and no characteristic sugar (wall chemotype III). The phospholipid pattern type is type PII (phosphatidylethanolamine is the characteristic phospholipid); the major menaquinone is MK-9. The fatty acid profile comprises saturated, unsaturated, and branched-chain fatty acids of the iso and anteiso types in addition to tuberculostearic acid (10Me-C18:0). A 16S ribosomal DNA sequence analysis revealed that the genus Lentzea is phylogenically related to the genera Actinosynnema, Saccharothrix, and Kutzneria. The type species of this genus is Lentzea albidocapillata sp. nov.; the type strain of this species is strain IMMIB D-958 (= DSM 44073).
The three-dimensional structure in solution of ferri-pyoverdin GM-II isolated from the culture medium of Pseudomonas fluorescens was determined by application of NMR methods to the Ga3+ analogue. Distance geometry calculations were performed with FILMAN using interproton distances and coupling constants as constraints. Further conformational analysis was carried out by energy minimization with MM2 and AMBER. Back-calculation of the NOESY spectra shows that the resulting structures are in agreement with the experimental data.
A mass spectrometric screening method for barbiturates in serum was developed. Under electron impact conditions barbiturates fragment by loss of HNCO. A 'constant neutral loss' scan of 43 u provides, therefore, an indication of the presence of members of this toxicologically relevant class of compounds. Subsequent identification is possible either by 'daughter' or by 'parent ion' scans. The detection limit for propallylonal, buto- and phenobarbital was determined as better than 1 micrograms ml-1 serum.
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The structures of two glycolipids produced by Cystobacter fuscus Cb 685 have been determined by 1H-NMR spectroscopy including 2D-techniques, as the positional isomers 1- and 2-isopentadecanoyl-3-beta-D-glucopyranosyl-X-glycerol. The chain length of the fatty acid residue determined by 13C-NMR spectroscopy has been confirmed by negative ion FAB-mass spectrometry.
A mass spectrometric screening method for the detection of barbiturates in serum will be presented. Fragmentation of barbiturates under EI conditions leads to a loss of HNCO. Therefore, "neutral loss scans" of 43 u allow the indication of possibly existing representatives of this class of compounds. Identification can be achieved by "daughter" or "parent ion scans". Thus, 10 micrograms/ml apro-, pento- and phenobarbital could be detected in serum.
In this study the methanol and aqueous extracts of four modern light-curing hybrid composite resins (unpolymerized and polymerized) were examined for eluable organic components by means of gas chromatography/mass spectroscopy. All substances found in the methanol extracts of the unpolymerized specimens were identified in the elutions of the cured materials too. Furthermore, all cured specimens contained at least one additional eluable component created during polymerization. In each composite resin there was at least one extractable substance which is classified as toxic.
It is shown that by a combination of positive and negative FAB mass spectrometry with collision activation using a tandem mass spectrometer diacyl glycerophosphoric acid ester mixtures can be analysed. The following results will be obtained: Molecular masses of the single components, nature of the residue bound to the phosphoric acid (choline, serine etc.), fatty acids present in the single components and (if different) their location at C-1/C-2 as well as a quantitative analysis both of the fatty acids in the mixture and of the various species making up the latter.
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4,9-Dihydroxyphenazine-1,6-dicarboxylic acid dimethylester, the ester form of a proposed 'missing link' in the biosynthesis of phenazines, has been isolated from a strain of Pseudomonas cepacia.
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The major fragmentation paths typical for the cardenolides system have been elucidated by labelling studies.
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