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Biomedical subjects

M H de Bruijn

Publications and source records attributed to M H de Bruijn.

11 recordsLinked to original sources
PubMed1992

Diagnosis of New World leishmaniasis: specific detection of species of the Leishmania braziliensis complex by amplification of kinetoplast DNA.

We have sequenced single kinetoplast DNA minicircles from three species and part of a minicircle from the fourth major species within the Leishmania braziliensis complex. Alignment of these sequences with each other and with those of other kinetoplastids allowed the selection of a pair of oligonucleotides suitable as primers in a polymerase chain reaction which is highly specific for the Leishmania braziliensis complex. The reaction is capable of detecting less than one femtogramme of kinetoplast DNA. It has been tested with crude specimens from South American leishmaniasis patients, potential wild animal reservoirs and sandfly vectors. The tests indicate that these primers are suitable for diagnosis of leishmaniasis and potentially useful in epidemiological surveys.

Animals↗
PubMed1987

Sequence of rat liver alpha 2-macroglobulin and acute phase control of its messenger RNA.

Six alpha 2-macroglobulin cDNA clones were isolated from two liver cDNA libraries produced from rats undergoing acute inflammation. The coding sequence for rat alpha 2-macroglobulin including its 27-residue signal peptide and the 3' - and part of the 5' nontranslated regions were determined. The mature protein consisting of 1445 amino acids is coded for by a 4790 +/- 40 nucleotide messenger RNA. It contains a typical internal thiol ester region and 25 cysteine residues which are conserved between rat and human alpha 2-macroglobulin. Although the amino acid sequences of rat and human alpha 2-macroglobulin share 73% identity, two small divergent areas of 17 and 38 residues were found, corresponding to 29 and 11% identity, respectively. These areas are located in the bait region and, therefore, may confer specific proteinase recognition capabilities on rat alpha 2-macroglobulin. Following an inflammatory stimulation, rat alpha 2-macroglobulin mRNA levels increased 214-fold over control values and reached a maximum at 18 h. By 24 h the levels had decreased to less than 30% of the maximum value. Transcription rates from the alpha 2-macroglobulin gene as measured in nuclear run-on experiments showed a less than 3-fold increase in nuclei from acutely inflamed rats as compared to controls. These results suggest that the accummulation of alpha 2M mRNA is due to the combined effects of increased transcription rates and post-transcriptional processing.

Amino Acid Sequence↗
PubMed1986

Differential amplification and disproportionate expression of five genes in three multidrug-resistant Chinese hamster lung cell lines.

At least five linked genes are amplified in the multidrug-resistant Chinese hamster ovary cell line CHRC5, selected with colchicine (A. M. Van der Bliek, T. Van der Velde-Koerts, V. Ling, and P. Borst, Mol. Cell. Biol. 6:1671-1678, 1986). We report here that only a subset of these, encoding the 170-kilodalton P-glycoprotein, are consistently amplified in three different multidrug-resistant Chinese hamster lung cell lines, selected with vincristine, daunorubicin, or actinomycin D. Within each cell line, genomic sequences homologous to the P-glycoprotein cDNA probe were amplified to different levels. The pattern of differential amplification was consistent with the presence of at least two and possibly three P-glycoprotein genes. In the actinomycin D-selected cell line, these genes were disproportionately overexpressed relative to the associated levels of amplification. These results underline a central role for P-glycoprotein in multidrug resistance. In the daunorubicin-selected cell line, another, as yet uncharacterized, gene was amplified but disproportionately underexpressed. Its amplification was therefore fortuitous. We present a tentative map of the region in the hamster genome that is amplified in the multidrug-resistant cell lines which were analyzed.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1985

Human complement component C3: cDNA coding sequence and derived primary structure.

The complete cDNA coding sequence and derived amino acid sequence of human complement component C3 are presented. The encoded precursor molecule contains a signal peptide of 22 amino acid residues, the beta chain (645 residues), and the alpha chain (992 residues). The two chains are joined by four arginine residues not present in the mature protein. Several functionally important sites have been localized, such as the thiolester site, the cleavage site liberating the anaphylatoxin, and two sites of cleavage by the serine protease factor I, as well as a peptide fragment with leukocyte mobilizing activity. At least two carbohydrate attachment sites, one on each chain, have been identified. Human C3 has 79% identity to mouse C3 at the nucleotide level and 77% identity at the amino acid level. The protease alpha 2-macroglobulin and complement component C4 show considerable homology to C3, suggesting that the three proteins have evolved from a common ancestor.

Amino Acid Sequence↗
PubMed1984

Nucleotide sequence of complementary DNA and derived amino acid sequence of murine complement protein C3.

The nucleotide sequences coding for murine complement component C3 have been determined from a cloned genomic DNA fragment and several overlapping cloned complementary DNA fragments. The amino acid sequence of the protein was deduced. The mature beta and alpha subunits contain 642 and 993 amino acids respectively. Including a 24 amino acid signal peptide and four arginines in the beta-alpha transition region, which are probably not contained in the mature protein, the unglycosylated single chain precursor protein preproC3 would have a molecular mass of 186 484 Da and consist of 1663 amino acid residues. The C3 messenger RNA would be composed of a 56 +/- 2 nucleotide long 5' non-translated region, 4992 nucleotides of coding sequence, and a 3' non-translated region of 39 nucleotides, excluding the poly A tail. The beta chain contains only three cysteine residues, the alpha chain 24, ten of which are clustered in the carboxy terminal stretch of 175 amino acids. Two potential carbohydrate attachment sites are predicted for the alpha chain, none for the beta chain. From a comparison with human C3 cDNA sequence (of which over 80% has been determined) an extensive overall sequence homology was observed. Human and murine preproC3 would be of very similar length and share several noteworthy properties: the same order of the subunits in the precursor, the same basic residue multiplet in the beta-alpha transition region, and a glutamine residue in the thioester region. The equivalent position of the known factor I cleavage sites in human C3 alpha could be located in the murine C3 alpha chain and the size and sequence of the resulting peptide were deduced. A comparison of the amino acid sequences of murine C3 and human alpha 2-macroglobulin is given. Several areas of strong sequence homology are observed, and we conclude that the two genes must have evolved from a common ancestor.

Amino Acid Sequence↗
PubMed1981

Sequence and organization of the human mitochondrial genome.

The complete sequence of the 16,569-base pair human mitochondrial genome is presented. The genes for the 12S and 16S rRNAs, 22 tRNAs, cytochrome c oxidase subunits I, II and III, ATPase subunit 6, cytochrome b and eight other predicted protein coding genes have been located. The sequence shows extreme economy in that the genes have none or only a few noncoding bases between them, and in many cases the termination codons are not coded in the DNA but are created post-transcriptionally by polyadenylation of the mRNAs.

Base Sequence↗
PubMed1980

A mammalian mitochondrial serine transfer RNA lacking the "dihydrouridine" loop and stem.

A unique transfer RNA has been identified in human and bovine mitochondria that lacks the "dihydrouridine" loop and stem structure. This tRNA is mitochondrially coded as shown by DNA sequence analysis of the human and bovine mitochondrial DNA. Sequence analysis of the RNA shows that it is post-transcriptionally modified by the addition of CCA at the 3' terminus and that at least one base is modified. As predicted by its anticodon (GCU, corresponding to the serine codons AGU/C) this tRNA can be aminoacylated with serine when purified mitochondria are incubated in a medium containing 3H-serine.

Animals↗
PubMed1980

Different pattern of codon recognition by mammalian mitochondrial tRNAs.

Analysis of an almost complete mammalian mitochondrial DNA sequence has identified 23 possible tRNA genes and we speculate here that these are sufficient to translate all the codons of the mitochondrial genetic code. This number is much smaller than the minimum of 31 required by the wobble hypothesis. For each of the eight genetic code boxes with four codons for one amino acid we find a single specific tRNA gene with T in the first (wobble) position of the anticodon. We suggest that these tRNAs with U in the wobble position can recognize all four codons in these genetic code boxes either by a "two out of three" base interaction or by U.N wobble.

Animals↗
PubMedDate not supplied

Leishmania (Viannia) lainsoni occupies a unique niche within the subgenus Viannia.

Leishmania lainsoni has recently been recognized as a new peripylarian species belonging to the subgenus Viannia and the L. braziliensis complex. It has been isolated from its sandfly vector, reservoir host and cutaneous lesions of human patients. Microscopical examination has shown characteristics which are different from those of other members of the L. braziliensis complex. Nuclear deoxyribonucleic acid (DNA) hybridization patterns with a beta tubulin probe and kinetoplast DNA buoyant density measurements show close similarities with other species of the L. braziliensis complex. However, kinetoplast DNA restriction enzyme fragment patterns of L. (V.) lainsoni isolates show similarities to L. mexicana complex species as well as weak cross hybridization. L. (V.) lainsoni is also amplified with L. braziliensis complex specific polymerase chain reaction (PCR) primers but it requires a lower annealing temperature and gives a 300 base pair PCR product. A possible model for the binding of PCR primers to the L. (V.) lainsoni kinetoplast DNA minicircle is proposed.

Animals↗
PubMedDate not supplied

Drosophila melanogaster mitochondrial DNA, a novel organization and genetic code.

The sequence of a 4,869 base-pair fragment of Drosophila melanogaster mitochondrial DNA is presented. It contains genes for cytochrome oxidase subunits I, II and III, ATPase subunit 6 and six tRNAs together with two unassigned reading frames. The gene organization differs from that of mammalian mitochondrial DNAs. Evidence is provided for a genetic code in which AGA codes for serine and the quadruplet ATAA is used in initiation of translation.

Amino Acid Sequence↗