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Biomedical subjects

M Mieschendahl

Publications and source records attributed to M Mieschendahl.

7 recordsLinked to original sources
PubMed1992

[Biological safety investigations of the production of human insulin by genetically engineered E. coli K-12 cells. 1. Survival capacity of the production strain in the digestive tract of Göttinger miniature swine].

The residence time of genetically engineered Escherichia coli K-12 cells in the digestive tract was tested by feeding Göttinger minipigs 10(10)-10(11) cells of strain W3110iqM15 (pSW3). This strain is a production strain for human insulin and carries the plasmid pSW3 which contains the genes for human insulin. The test strain could be selected as white colonies grown on McConkey ampicillin plates and could be identified by complementation analysis due to its lacZ M15 deletion. The strain could be isolated from the faeces of the animals up to 72 h after feeding, thereafter no cells of the phenotype of the test strain grew on McConkey ampicillin plates. So the production strain for human insulin W3110iqM15 (pSW3) was not able to colonize the digestive tract of the Göttinger minipig. Feeding the genetically engineered E. coli K-12 cells had no influence on the welfare of the animals.

Animal Welfare↗
PubMed1992

Bioluminescence-based detection of genetically engineered microorganisms in nonsterile river water.

The luminescence genes of the marine bacterium Vibrio fischeri were cloned into a lac expression vector and introduced into Escherichia coli and Pseudomonas putida. Survival of the cells in river water samples was monitored by light measurements. Whereas E. coli survived in sterilized river water for more than 29 days, it died off in nonsterile river water after 9 to 13 days. The engineered P. putida cells survived in nonsterile river water for more than 137 days. The detection limit for E. coli was 11 cells/ml.

Cell Survival↗
PubMed1985

F'-coded, temperature-sensitive lambda cI857 repressor gene for easy construction and regulation of lambda promoter-dependent expression systems.

We describe the construction and properties of an F' factor which carries the temperature-sensitive cI857 allele of the repressor gene of coliphage lambda and which lacks the lambda cro function. This episome can easily be transferred to any F- and F' Escherichia coli strain, thus facilitating the construction and regulation of lambda promoter-dependent expression systems without the use of defective prophages.

Bacteriophage lambda↗
PubMed1983

Does the lactose carrier of Escherichia coli function as a monomer?

The purified lactose carrier of Escherichia coli (product of the lac Y gene) is shown to be a monomer in detergent micelles of dodecyl-O-beta-D-maltoside. The negative-dominant phenotype of mutant carriers (lacY-d mutants) could not be verified by measurements of the rate of galactoside transport in lacY+/Y-d diploid strains. It is proposed that the membrane-embedded carrier functions as a monomer in galactoside-H+ symport.

Biological Transport↗
PubMed1981

Mutations in the lacY gene of Escherichia coli define functional organization of lactose permease.

Mutations in the lacY gene of Escherichia coli have been used to analyze the functional organization of lactose permease. Deletions suggest that the NH2 terminus of lactose permease is not essential and can be replaced by residues of the cytoplasmic enzyme beta-galactosidase. Negative dominant mutations in the lacY gene can be explained by the assumption that membrane-associated lactose permease is active as a dimer or oligomer. The map positions of these mutations and other point mutations that lower or alter the sugar specificity define regions of lactose permease involved in sugar or proton binding and transport.

Amino Acid Sequence↗