Biomedical subjects

J Meiwes

Publications and source records attributed to J Meiwes.

8 recordsLinked to original sources

PubMed2000

Friulimicins: novel lipopeptide antibiotics with peptidoglycan synthesis inhibiting activity from Actinoplanes friuliensis sp. nov. I. Taxonomic studies of the producing microorganism and fermentation.

A strain that produces new lipopeptide antibiotics is a new species of the genus Actinoplanes for which we propose the name Actinoplanes friuliensis (type strain: HAG 010964). The strain is an actinoplanete actinomycete having cell wall II composition and forming sporangia. Comparisons with Actinoplanes spp. which have similarities with our isolate, including fatty acid analysis, showed that the isolate belongs to a new species. Taxonomic studies and fermentation are presented.

Actinomycetales↗

PubMed2000

Friulimicins: novel lipopeptide antibiotics with peptidoglycan synthesis inhibiting activity from Actinoplanes friuliensis sp. nov. II. Isolation and structural characterization.

Four novel lipopeptide antibiotics, friulimicins A, B, C, and D, were isolated from cultures of Actinoplanes friuliensis HAG 010964 after fermentation in different nutrient media. The new compounds were separated by ion-exchange chromatography from the acidic lipopeptides of the amphomycin type also present in the culture fluid, compounds A-1437 A, B, E, and G. The principal constituent friulimicin B, C59H94N14O19, was structurally characterized by mass spectrometric investigations of its hydrolysis and partial degradation products and by sequencing of the cyclic acyl peptide. The NMR data of friulimycin B and the amphomycin constituent A-1437 B were completely assigned by a variety of 2-D experiments, and confirmed the structures determined by mass spectrometry. All 8 lipopeptides possess an identical peptide macrocycle as their central element, linked via a diaminobutyric acid N-terminal either to an acylated asparagine residue or, in the case of the amphomycin series, to an acylated aspartic acid residue. The structures of the amphomycins have now been revised to take account of the peptide framework described herein and the determined cis-configuration of the exocyclic double bond. As a consequence of their higher isoelectric points, the new compounds friulimicin A, B, C, and D have different properties than the amphomycins.

Actinomycetales↗

PubMed1996

A new esterase for the cleavage of pivalic acid-containing prodrug esters of cephalosporins.

An extracellular esterase from the actinomycetes Amycolatopsis orientalis was found by screening. It is capable of splitting the isomeric mixture (K/J) of (I, Scheme 1) into 7-amino-3-methoxymethyl-3-cephem-4-carboxylic acid, pivalic acid, and acetaldehyde with a high yield. The purified enzyme of 55.4 Kd by SDS-PAGE shows an N-terminal sequence of VRTCADLVRTYDLPGAVTH. The isoelectric point is 8.9 +/- 0.1. It can be immobilized with good yield to VA-Epoxy Biosynth. Besides the above-mentioned reaction, the esterase cleaves many other esters such as methyl-2-chloropropionic acid.

Actinobacteria↗

PubMed1994

Isolation and biological characterization of staphyloferrin B, a compound with siderophore activity from staphylococci.

A highly hydrophilic compound with siderophore activity has been isolated from the supernatant of Staphylococcus hyicus DSM 20459 grown under iron-restricted conditions. The metabolite, named staphyloferrin B, is strictly iron-regulated and produced by a large variety of staphylococci strains. In vivo iron transport measurements and the growth-promoting activity in a bioassay establish staphyloferrin B as the second siderophore for staphylococci besides the previously described staphyloferrin A. The structure elucidation revealed 2,3-diaminopropionic acid, citrate, ethylenediamine and 2-ketoglutaric acid as structural components of the compound. Thus, staphyloferrin B is a structurally new siderophore of the complexone type.

Biological Assay↗

PubMed1991

Clostripain: production and use for peptide synthesis.

The arginine-specific protease Clostripain could efficiently be produced following improved fermentation and isolation procedures. Preparative scale kinetically controlled peptide synthesis of -Arg-Pro- and Arg-Xaa- containing peptides could successfully be performed in high yields with free and immobilized enzyme preparations.

Amino Acid Sequence↗

PubMed1990

Staphyloferrin A: a structurally new siderophore from staphylococci.

Two ferric ion-binding compounds, designated staphyloferrin A and B, were detected in the culture filtrates of staphylococci grown under iron-deficient conditions. Staphyloferrin A was isolated from cultures of Staphylococcus hyicus DSM 20459. The structural elucidation of this highly hydrophilic, acid-labile compound revealed a novel siderophore, N2,N5-di-(1-oxo-3-hydroxy-3,4-dicarboxybutyl)-D-ornithine, which consists of one ornithine and two citric acid residues linked by two amide bonds. The two citric acid components of staphyloferrin A provide two tridentate pendant ligands, comprising of a beta-hydroxy, beta-carboxy-substituted carboxylic acid derivative, for octahedral metal chelation. The CD spectrum of the staphyloferrin A ferric complex indicates a predominant A configuration about the ferric ion center. The uptake of ferric staphyloferrin A by S. hyicus obeys Michaelis-Menten kinetics (Km = 0.246 microM; vmax = 82 pmol.mg-1.min-1), indicating active transport of this siderophore. The staphyloferrin A transport system is different from that of the ferrioxamines as shown by an antagonism test. Production of staphyloferrin A is strongly iron-dependent and is stimulated by supplementation of the medium with either D- or L-ornithine. DL-[5-14C]ornithine was incorporated into staphyloferrin A, demonstrating that ornithine is an intermediate in staphyloferrin A biosynthesis.

Amino Acids↗

PubMed1990

Isolation and characterization of staphyloferrin A, a compound with siderophore activity from Staphylococcus hyicus DSM 20459.

A highly hydrophilic compound was isolated from low iron culture broth of Staphylococcus hyicus DSM 20459 which exhibits siderophore activity to the producer and 37 other staphylococci. The previously unknown metabolite was designated staphyloferrin A and consists of two molecules of citric acid, each linked to D-ornitine by an amide bond. Using an ion-pair HPLC-system we detected staphyloferrin A and a second iron regulated compound (staphyloferrin B) in the culture fluid of several Staphylococcus strains. We found no evidence that staphylococci synthesize catecholor hydroxamate-type siderophores.

Chromatography, High Pressure Liquid↗

PubMed1990

Production of desferrioxamine E and new analogues by directed fermentation and feeding fermentation.

Streptomyces olivaceus TU 2718 produces the siderophore desferrioxamine E. Production depends on L-lysine and iron concentrations in the medium. With optimized conditions the yield of desferrioxamine E could be increased to 12 g/l in feeding fermentations. Supplementation of the basic production medium with natural and synthetic precursors of desferrioxamine E led to the production of twelve new analogues of desferrioxamine E.

Bacteriological Techniques↗