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Biomedical subjects

H de Vries

Publications and source records attributed to H de Vries.

At least 109 records · Page 6Linked to original sources
PubMed1988

Isolation and analysis of the Neurospora crassa Cyt-21 gene. A nuclear gene encoding a mitochondrial ribosomal protein.

The Neurospora crassa nuclear mutant cyt-21-1 (originally 297-24; Pittenger, T.H., and West, D.J. (1979) Genetics 93, 539-555) has a defect leading to gross deficiency of mitochondrial small ribosomal subunits. Here, we have cloned the cyt-21+ gene from a N. crassa genomic library, using the sib selection procedure (Akins, R. A., and Lambowitz, A. M. (1985) Mol. Cell Biol. 5, 2272-2278). The genomic clone contains a short split gene encoding a basic protein of 107 amino acid residues. This protein shows strong homology to Escherichia coli ribosomal protein S-16. Comparison of mutant and wild-type mitochondrial ribosomal proteins (Kuiper, M. T. R., Holtrop, M., Vennema, H., Lambowitz, A. M., and de Vries, H. (1988) J. Biol. Chem. 263, 2848-2852) indicates that the cyt-21 gene encodes N. crassa mitochondrial ribosomal protein S-24. The expression of the cyt-21+ gene is regulated such that the level of the putative cyt-21+ mRNA is increased about 5-fold when mitochondrial protein synthesis is inhibited. We suggest that this reflects part of a general mechanism for coordinately activating Neurospora nuclear genes that encode mitochondrial constituents in response to impaired mitochondrial function. This is the first report of the cloning and characterization of a mitochondrial ribosomal protein gene from N. crassa.

Amino Acid Sequence↗
PubMed1988

A 3' splice site mutation in a nuclear gene encoding a mitochondrial ribosomal protein in Neurospora crassa.

We showed previously that the cyt-21+ gene of Neurospora crassa encodes a mitochondrial ribosomal protein homologous to Escherichia coli ribosomal protein S-16 (Kuiper, M. T. R., Akins, R. A., Holtrop, M., de Vries, H., and Lambowitz, A. M. (1988) J. Biol. Chem. 263, 2840-2847). A mutation in this gene, cyt-21-1, results in deficiency of mitochondrial small ribosomal subunits and small rRNA (Collins, R. A., Bertrand, H., LaPolla, R. J., and Lambowitz, A. M. (1979) Mol. Gen. Genet. 177, 73-84). In the present work, cloning and sequencing of the cyt-21-1 mutant allele show that it contains a single dG to dA transition at the 3' splice site AG of the first intron in the protein coding region. This mutation leads to inactivation of the normal 3' splice site and activation of a cryptic 3' splice site, 15 nucleotides downstream. The use of this cryptic splice site results in an in-frame deletion of 5 amino acids from the cyt-21 protein. Comparison of mutant and wild-type mitochondrial small ribosomal subunit proteins showed one protein, S-24, with an altered electrophoretic mobility, consistent with the predicted deletion. The mutant ribosomal protein is still capable of binding to mitochondrial small ribosomal subunits, but results in abnormal mitochondrial ribosome assembly.

Alleles↗
PubMed1987

[Sewage sludge].

Current knowledge of sewage sludge is reviewed, particular reference being made to the possible effect on the health of herds of cattle. The following measures should be urgently and seriously considered: more effective watching of sewage disposal; assessments on sewage disposals, related to the costs of alternatives; stricter checks on diffuse sources of pollution (refuse dumps, agriculture, etc.); development of long-term views to prevent the appearance of waste matter injurious to health and putting a stop to methods of production in which these wastes are released. The disposal of toxic substances in the environment was reduced by fifty per cent in particular sections during the past five years. When this is chosen as an objective, the Netherlands will be clean in approximately fifty years. In the opinion of experts, this would appear to be a practical approach which can be accomplished by considerable economic efforts. When the thoughtless disposal of toxic substances comes to an end, it will be possible to use sewage sludge in agriculture without this becoming a hazard to the health of animals and man.

Animals↗
PubMed1987

Studies on curcumin and curcuminoids. IX: Investigation of the photobiological activity of curcumin using bacterial indicator systems.

The dye curcumin is a natural, nontoxic food constituent. On irradiation with visible light, curcumin proves to be phototoxic for Salmonella typhimurium and Escherichia coli, even at very low concentrations. The observed phototoxicity makes curcumin a potential photosensitizing drug which might find application in the phototherapy of, for example, psoriasis, cancer, and bacterial and viral diseases.

Catechols↗
PubMed1987

[Budd-Chiari syndrome as a late complication following closure of an atrial septal defect].

A case of a Budd-Chiari syndrome in a 19-year-old female patient is reported who had undergone surgical closure of a secundum atrial septal defect 13 years before. 8 months before the development of the Budd-Chiari syndrome she started to take oral contraceptives. The clinical picture of the Budd-Chiari syndrome developed within several days. The inferior vena cava did not fill with contrast dye when an angiography was performed using the right vena iliaca approach. The contrast dye disappeared through collateral veins (vena azygos, vena hemiazygos). After 4 days of treatment with systemic streptokinase she underwent open-heart surgery. The orifice of the inferior vena cava was occluded to a diameter of 6 mm. No thrombi were found. The lesion was corrected with two patches, one in the right atrium and the other in the inferior vena cava. This case report demonstrates that a Budd-Chiari syndrome is a possible late complication after closure of an atrial septal defect which should be treated by surgery.

Adult↗
PubMed1986

The E35 stopper mutant of Neurospora crassa: precise localization of deletion endpoints in mitochondrial DNA and evidence that the deleted DNA codes for a subunit of NADH dehydrogenase.

Two types of defective mitochondrial DNA molecules with large deletions (5 kbp and 40 kbp) have previously been identified in the stopper mutant, E35, of Neurospora crassa. The junction fragments spanning the deletion endpoints have now been cloned and sequenced, and their sequences compared with those of the corresponding wild-type fragments. We show that both types of defective mitochondrial DNAs result from deletions of sequences flanked by short direct repeats, which are themselves parts of larger inverted repeat sequences. In every case, the short direct repeat sequences consist of a run of pyrimidines in one strand and purines in the other. We also report the sequence of a 2151-bp HindIII fragment, which is deleted in both of the defective mitochondrial DNAs. Besides the previously identified gene for a methionine tRNA, the 2151-bp DNA sequence contains an open reading frame with the potential to code for a hydrophobic protein 583 amino acids long. This hydrophobic protein has three blocks of significant homology with proteins coded by URF2 found in other mitochondrial genomes. Since the mammalian mitochondrial URF2 has recently been shown to code for a subunit of NADH dehydrogenase, part of the DNA sequence missing in the E35 stopper mutant of N. crassa may also code for a subunit of NADH dehydrogenase.

Amino Acid Sequence↗
PubMed1985

Specific inhibition of mitochondrial protein synthesis influences the amount of complex I in mitochondria of rat liver and Neurospora crassa directly.

Specific inhibition of mitochondrial protein synthesis reduces the oxidation rate of NADH-linked substrates in rat liver as well as in Neurospora crassa mitochondria. The present study shows that this is due to the fact that inhibition of mitochondrial protein synthesis leads to a decrease of the concentration of active complex I. Therefore, these results demonstrate that at least one of the genes for the subunits of complex I is localized on mitochondrial DNA.

Animals↗
PubMed1985

The Neurospora mitochondrial genome: the region coding for the polycistronic cytochrome oxidase subunit I transcript is preceded by a transfer RNA gene.

We have sequenced a 682 bp fragment of Neurospora crassa mitochondrial DNA to complete the sequence between the gene for cytochrome b and the unassigned reading frame, URF U. The sequence contains a gene for a cysteine tRNA. The 5' end of the 6 kb polycistronic transcript of cytochrome c oxidase subunit 1 is immediately downstream from this tRNA. This shows that also in fungal mitochondria tRNAs can be used as processing signals, whereas palindromic sequences containing double Pst I sites, also present in this region, are not used for processing.

Base Sequence↗
PubMed1979

Laboratory of Physiological Chemistry, State University Groningen, Netherlands.

To obtain more information about the arrangement of Hind III restriction fragments in the tRNA-rRNA region of the Neurospora crassa mitochondrial (mt) DNA we have cleaved the mtDNA with Hpa I and Hind II. We could construct additional cleavage maps for these enzymes. Hybridization of rRNAs to Hind II fragments confirmed the existence of an intervening region of about 2,300 basepairs in the 24S rRNA (Hahn et al., Cell, in press). About seven tRNA genes, among which the genes for tRNA1Ser and tRNAMetM, are located in a segment of about 5,000 bp separating the 24S and 17S rRNA genes. Another cluster of 14 tRNA genes is found adjacent to the other end of the 24S gene. The genes for tRNALeu1 and tRNAMetF are located in this cluster.

DNA Restriction Enzymes↗
PubMed1979

Antimicrobial activity of crude juices of Allium ascalonicum, Allium cepa and Allium sativum.

Crude juices of garlic (Allium sativum), onion (Allium cepa) and shallots (Allium ascalonicum) were tested in an agar diffusion test for their growth inhibitory effect on five gram negative and three gram positive bacterial species and two yeast species. All test organisms were inhibited by garlic juice, whilst onion and shallot juice showed no effect upon gram negative bacteria. Garlic juice was investigated in more detail. Addition of complex-forming agents and organic matter to the crude juice reduced its activity on all test organisms. Volatile substances showed a strong inhibitory activity after exposure for 8 hours or longer at 23 degrees C or 37 degrees C. Minimal inhibition concentrations determined in a dilution test were found to be high for gram negative bacteria and low for both yeast species. The D-values of the different test organisms in undiluted garlic juice were calculated. P. aeruginosa had a very low D-value, whilst the bacteriostatic concentration was high. This indicates a large concentration exponent of crude garlic juice for this organism. The opposite was found for S. aureus. In view of the strong antibiotic properties and the complete absence of development of resistance further investigation upon the principles of the antimicrobial activity of juices from Allium species merits consideration.

Anti-Bacterial Agents↗