Biomedical subjects

Uta Böckelmann

Publications and source records attributed to Uta Böckelmann.

3 recordsLinked to original sources

PubMed2006

Bacterial extracellular DNA forming a defined network-like structure.

It is generally assumed that nucleic acids are localized inside of living cells and that their primary function is the storage of information. In contrast, extracellular DNA is mainly considered as a remnant of lysed cells. Here, we report the formation of extracellular bacterial DNA as a spatial structure. An aquatic bacterium, strain F8, was isolated, which produced a stable filamentous network of extracellular DNA. Different staining and enzymatic techniques confirmed that it was DNA. We were able to amplify the 16S rRNA gene from the extracellular DNA. Restriction endonuclease cleavage and randomly amplified polymorphic DNA analysis of extracellular and genomic DNAs revealed major similarities, but also some differences in both sequences. Our data demonstrate a new function and relevance for extracellular DNA.

Bacteria↗

PubMed2003

A new enzymatic method for the detachment of particle associated soil bacteria.

A new enzymatic technique for the detachment of bacteria from soil particles was developed and applied to different soil samples taken at various sampling sites and depths. Many soil microorganisms are closely associated with the organic matrix of soil particles. They produce extracellular polymeric substances (EPS), which promote the irreversible adhesion of cells to soil particulates. To characterize the EPS, a prestaining of the soil samples with different lectins was performed. Samples from a sewage field, an urban park, a farmland, a mixed forest and garden mold were stained with a set of FITC-labelled lectins from Triticum vulgaris, Ulex europaeus, Concanavalin A and Pseudomonas aeruginosa. Based on the results, a combination of alpha-glucosidase, beta-galactosidase and a lipase was chosen for degradation of the EPS structures, followed by gentle mechanical and chemical dispersion in a modified sodium pyrophosphate buffer. The samples were fixed with formaldehyde and total cell counts were determined by DAPI staining. With the exception of the wheat field sample, this technique revealed up to 22-fold higher total cell counts for all investigated soil samples compared to the conventional detachment method, a simple dispersion with sodium pyrophosphate buffer. Efficiency of the technique was assessed by scanning electron microscopy. These images showed convincingly that the enzymatic treatment followed by sonication efficiently detached the bacteria and left the soil particles almost blank.

Bacteria↗

PubMed2002

Investigation of lotic microbial aggregates by a combined technique of fluorescent in situ hybridization and lectin-binding-analysis.

A technique combining fluorescent in situ hybridization and lectin-binding-analysis (FISH-LBA) was developed and applied for the simultaneous detection of cellular components and glycoconjugates in lotic microbial aggregates (river snow). River snow aggregates were directly collected from the bulk water phase into coverslip chambers, in which the complete procedure including fixation, fluorescent in situ hybridization, lectin-binding and optical analysis by confocal laser scanning microscopy was performed. Neither autofluorescence originating from phyotosynthetic organisms nor inorganic particles did negatively interfere with the FISH-LBA technique. In river snow samples obtained from the river Elbe, Germany, distinct compartments of the river snow structure could be visualized with FITC-labelled lectins from Triticum vulgaris, Limulus polyphemus, Arachis hypogaea, Phaseolus vulgaris and Pseudomonas aeruginosa, binding to frequently occurring saccharide residues in the river snow matrix. The analysis could be performed on different levels of complexity. The combined technique visualized bacteria of different phylogenetic groups in the entire river snow structure as well as glycoconjugate components linked with various microcolonies. Different lectins stained slime layers and cell-envelopes of individual eukaryotic and prokaryotic cells. Consequently, application of the FISH-LBA technique allows the linkage between cellular and glycoconjugate identity in complex microbial communities.

Animals↗