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M Hildebrandt

Publications and source records attributed to M Hildebrandt.

46 records · Page 3Linked to original sources
PubMed1991

Library-independent cloning of genomic fragments adjacent to vector integration sites: isolation of the EB4-PSV gene from a Dictyostelium gene disruption transformant.

We have designed an efficient procedure to clone genomic DNA adjacent to the integration site of transformation vectors. Using this method on a Dictyostelium gene disruption transformant, we have cloned a 5kb fragment which has previously escaped isolation by conventional library screening. Our protocol eliminates recloning of the original vectors which are often integrated in multiple tandem copies (1) but specifically recovers vectors containing genomic fragments adjacent to the integration site. The protocol is useful to isolate flanking fragments in gene disruption transformants to characterize flanking regions which may influence the expression of transformed genes by position effects and to identify sites of insertional mutagenesis.

Amino Acid Sequence↗
PubMed1991

Tissue-specific regulation of dipeptidyl peptidase IV expression during development.

The patterns of dipeptidyl peptidase (DPP) IV activity and protein amount in different rat organs during development were compared. In order to elucidate the molecular basis for these patterns, total RNA was isolated from lung and kidney at different stages of development and analysed by Northern-blot hybridization using an oligonucleotide derived from the DPP IV cDNA sequence. This oligonucleotide hybridized to two distinct mRNAs of approx. 3.2 and 4.8 kb respectively. During kidney development, the pattern for DPP IV mRNA paralleled that of DPP IV activity and protein amount, suggesting that, in kidney, the expression of DPP IV is primarily controlled at the transcriptional level. In contrast, the magnitude of DPP IV activity during lung development compared with that of DPP IV mRNA in lung suggests that post-transcriptional mechanisms are involved in regulating the expression of DPP IV in lung. Organ-specific regulation of DPP IV expression may provide a useful model for further comparative studies of transcriptional and post-transcriptional mechanisms of DPP IV expression within the same organism.

Aging↗
PubMed1991

Structure, expression, and inactivation by gene disruption of the Dictyostelium discoideum prespore gene EB4.

We present the nucleotide sequence of the cell type specific prespore gene EB4 which encodes a protein containing a hydrophobic leader sequence and two distinct domains of amino acid repeats. By RNase protection experiments we have determined the genomic organization of the gene which differs substantially from the previously published data. An antibody directed against one of the repeat structures (hexamer repeat) specifically reacts with a developmentally regulated antigen of 58 kd. Gene disruption transformants were obtained by transformation with a genomic DNA fragment. The transformants express a 3' truncated mRNA and do not react with the anti-hexamer antibody. So far, we could not detect any phenotypic aberrations in the transformed cell line.

Amino Acid Sequence↗
PubMed1991

The Dictyostelium discoideum EB4 gene product and a truncated mutant form of the protein are localized in prespore vesicles but absent from mature spores.

Using polyclonal antibodies directed against two different parts of the predicted Dictyostelium prespore protein EB4-PSV, we have investigated the regulation and localization of its 58-kDa gene product in wild-type cells and a 31-kDa truncated form in the gene disruption transformant A3. In both strains, the protein is synthesized during aggregation and is found in the membrane fraction of prespore vesicles (PSV). In contrast to other PSV proteins, the EB4 gene product is not found in mature spores.

Amino Acid Sequence↗
PubMed1989

Optimization and in situ detection of Escherichia coli beta-galactosidase gene expression in Dictyostelium discoideum.

We show that a fusion gene, containing the promoter and 5'-noncoding region of a Dictyostelium discoideum actin 6 gene linked to the Escherichia coli beta-galactosidase (beta Gal) gene (lacZ), directs the production of functionally active beta Gal in D. discoideum and that the enzyme can be detected by staining in situ; a procedure which will be of great value in analyzing cell-type-specific gene expression. We illustrate this by fusing lacZ to the promoter of the prespore-specific gene, D19, and localizing expressing cells in migrating slugs. Optimal expression requires the inclusion of termination and polyadenylylation signals and we describe pDDlac, a vector containing a multiple cloning site upstream from a lacZ-Dictyostelium terminator fusion, which can be used to analyze regulated promoters.

Amino Acid Sequence↗
PubMed1986

Pediatric vestibular evaluation with harmonic acceleration.

A group of 101 otologically normal infants and children were evaluated with low-frequency harmonic acceleration (HA) to determine the feasibility of use of this procedure in evaluation of vestibular function in a pediatric population. Ninety-six of the subjects were successfully tested and normative data are presented. A maturational trend was noted (in the presence of nystagmus) in subjects up to 10 months of age and in the phase-lag measurement up to approximately 4 years of age.

Age Factors↗
PubMedDate not supplied

Simultaneous genotyping of human platelet antigens (HPA) 1 through 6 using new sequence-specific primers for HPA-5.

BACKGROUND: Polymerase chain reaction using sequence-specific primers is widely used for genotyping human platelet antigens (HPA). However, the results of HPA-5 genotyping are still problematic. STUDY DESIGN AND METHODS: New sequence-specific primers were designed for HPA-5 that, together with already published primers, allow simultaneous genotyping of HPA-1, -2, -3, -4, -5, and -6. The reliability of the described protocol was determined by using reference DNA samples as well as samples from healthy blood donors. RESULTS: All primers produced specific amplification products. The genotype and the previously ascertained phenotype of the tested specimens were in concordance in all cases. CONCLUSION: The described polymerase chain reaction protocol allows rapid, reliable, simultaneous genotyping of HPA-1, -2, -3, -4, -5, and -6.

Alleles↗
PubMedDate not supplied

Decontamination of the oral cavity. Effect of six local anti-microbial preparations in comparison to water and parafilm as controls.

Six preparations (four liquid and two solid) were tested in a double-blind crossover design for their anti-bacterial effect on aerobic and anaerobic bacteria in saliva of 12 volunteers. The four liquid preparations contained either tyrothricin, hexetidine, hydrogen peroxide or ethanol and were tested against a rinse with water as control. The two solid preparations, in the form of lozenges, contained tyrothricin in doses of 4 or 10 mg and were tested against parafilm. A single rinse with either tyrothricin or hexetidine resulted in a significant reduction of aerobic and anaerobic bacteria in saliva which lasted for the whole 1 h observation period and was considerably more effective than hydrogen peroxide or ethanol. Similar results were seen with the solid preparations. The lozenge containing 10 mg tyrothricin was the most effective and was the only formulation capable of reducing oral aerobic bacterial counts by a factor of approximately 100.

Adult↗