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C Schüller

Publications and source records attributed to C Schüller.

28 records · Page 2Linked to original sources
PubMed1994

Identification of active cytomegalovirus infection by analysis of immediate-early, early and late transcripts in peripheral blood cells of immunodeficient patients.

Owing to the persistence of viral DNA in leukocytes after primary CMV infection, detection of CMV DNA in these cells does not necessarily represent active infection. To identify CMV replication more precisely we have analysed immediate-early, early and late CMV transcripts by RNA amplification. The assay seems to be specific for active infection since no RNA-derived PCR products were obtained from healthy seropositive persons. The late UL83 transcript was detected in 80% of the patients with active CMV infections. Diagnosis of CMV replication by amplification of early and immediate-early transcripts was considerably less sensitive. In the case of continual CMV DNA detection in blood leukocytes by PCR without pp65 antigenemia the analysis of defined CMV transcripts would allow differentiation of active and non-active infection. In two cases the RNA assay became negative prior to DNA PCR analysis and pp65 antigen detection upon antiviral treatment, indicating that RNA amplification could be a suitable assay for early detection of the end of viral replication. No strong correlation was found between RNA detection and appearance of clinical symptoms. The development of CMV disease probably depends more on the extent of the functional impairment of the immune system.

AIDS-Related Opportunistic Infections↗
PubMed1993

A Saccharomyces cerevisiae UAS element controlled by protein kinase A activates transcription in response to a variety of stress conditions.

Transcription of the Saccharomyces cerevisiae CTT1 gene encoding the cytosolic catalase T is activated by a variety of stress conditions: it is derepressed by nitrogen starvation and induced by heat shock. Furthermore, it is activated by osmotic and oxidative stress. This study shows that a CTT1 upstream region previously found to be involved in nitrogen, cAMP and heat control (base pairs -382 to -325) contains a UAS element (STRE, -368 to -356), which is sufficient for the activation of a reporter gene by all types of stress acting on CTT1. Gel retardation experiments demonstrated the existence of a factor specifically binding to STRE, but to a lesser extent to mutated elements having partly or entirely lost the ability to mediate stress control. Heat activation of STRE, but not of a canonical heat shock element, is enhanced by a ras2 defect mutation, which enhances thermotolerance, and is dramatically reduced by a bcy1 disruption mutation, which decreases thermotolerance. It can be hypothesized, therefore, that the novel stress control element is important for the establishment of induced stress tolerance.

Base Sequence↗
PubMed1992

[Neodymium--Yag laser in the recanalization of arterial occlusions].

Failure of the guide-wire to recanalize some arterial total occlusion does not preclude balloon angioplasty. Nowadays there are recanalization devices such as the mechanical atherectomy and Lasers. The following report describes the successful use of the Nd: YG Laser in the recanalization of a common iliac artery total occlusion in a patient with claudication, rendering possible balloon angioplasty and a Palmaz Stent implantation, which is the first case performed in our country.

Aged↗
PubMed1991

Heat shock factor-independent heat control of transcription of the CTT1 gene encoding the cytosolic catalase T of Saccharomyces cerevisiae.

Transcription of the Saccharomyces cerevisiae CTT1 gene encoding the cytosolic catalase T has been previously shown to be derepressed by nutrient stress. To investigate whether expression of this gene is also affected by other types of stress, the influence of heat shock on CTT1 expression was studied. The results obtained show that expression of the gene is low at 23 degrees C and is induced rapidly at 37 degrees C. By deletion analysis, a promoter element necessary for high level induction by heat shock was located between base pairs -340 and -364 upstream of the translation start codon. This region was demonstrated to be sufficient for heat shock control by placing it upstream of a S. cerevisiae LEU2-lacZ fusion gene. Mutagenesis of the region showed that the response to heat shock is not mediated by a sequence similar to canonical heat shock elements, but by DNA elements also involved in nutrient control of transcription. Catalase T appears to have a function in protecting yeast cells against oxidative damage under stress conditions. Catalase T-containing strains are less sensitive to exposure to 50 degrees C ("lethal heat shock") than isogenic catalase T-deficient mutants, and catalase T-containing strains pretreated by incubation at 37 degrees C are less sensitive to H2O2 than pretreated catalase-deficient mutants.

Base Sequence↗
PubMed1990

Evolution of nucleic acids coding for ribonucleases: the mRNA sequence of mouse pancreatic ribonuclease.

The cDNA of mouse pancreatic mRNA has been cloned. After the library was screened with a rat ribonuclease cDNA probe, the positive clones were isolated and sequenced. There were no differences from the previously determined protein sequence. The mRNA codes for a preribonuclease of 149 amino acid residues including a signal peptide of 25 amino acids. The 3' noncoding region has a length of 260 bp, and the total mRNA length is approximately 940 bp. Comparison with the rat pancreatic ribonuclease sequence showed a high rate of nucleotide substitution. Within the coding region, nonsynonymous and synonymous substitution rates are 4.3 X 10(-9) and 15 X 10(-9) nucleotide substitutions/site/year, respectively. The latter value is one of the highest rates observed in the molecular evolution of mammalian nuclear genes. In the signal sequences the synonymous substitution rate is much lower and about the same as the nonsynonymous rate. Signal sequences of other mouse and rat proteins also exhibit little difference between synonymous and nonsynonymous rates. The sequences of rat and mouse pancreatic ribonuclease messengers were compared with those of bovine pancreatic, seminal, and brain ribonuclease. While the 3' noncoding regions of rat and mouse are very similar, as are those of the three bovine messengers, there is no significant similarity between both rodent and the three bovine messengers for the greater part of these regions. There is a duplication of approximately 50 nucleotides in the 3' noncoding region of the bovine messengers, with a region rich in A and C in between. The presence of this structural feature may be correlated with recent gene duplications that have occurred in the bovine genome.

Amino Acid Sequence↗
PubMed1990

Ribonuclease in different chromosomal species of the mole rat, superspecies Spalax ehrenbergi: concentration in the pancreas and primary structure.

Ribonucleases are found in considerable quantities in the pancreas of a number of mammalian taxa and a few reptiles. The ribonuclease content varies greatly in different species. Large quantities are found in ruminants and species that have a ruminant-like digestion and in a number of species with coecal digestion. This is a response to the necessity of digesting large amounts of RNA derived from the microflora of the stomach of ruminants or species with ruminant-like digestion or of the coecum of species with coecal digestion. The amino acid sequence of pancreatic ribonuclease from the chromosomal species 2n = 60 of the mole rat, superspecies Spalax Ehrenbergi was determined. From the comparison of the sequence with those of other mammalian species we found that Spalax diverged from the myomorph rodent branch before the divergence of the Muridae (mouse, rat) from the Cricetidae (hamster, muskrat). Spalax ribonuclease shares several amino acid residues with other myomorph rodent species. These are not or only rarely observed outside this rodent suborder. Although the ribonuclease content varies greatly in different mammalian species, the variation in content between individuals within a species is small. Spalax is an exception to this with ribonuclease contents varying over more than an order of magnitude in different individuals. Ribonucleases isolated from the chromosomal species 2n = 52, 2n = 58 and 2n = 60 have identical elution positions on reversed-phase HPLC. The enzyme from the 2n = 54 species, however, elutes at a slightly earlier elution position. No amino acid sequence differences have been found hitherto between the ribonucleases of the four chromosomal species of Spalax ehrenbergi occurring in Israel. However, due to lack of material we were unable to determine more than about 20% of the sequence of the enzyme from the 2n = 54 species, which is the oldest offshoot.

Amino Acid Sequence↗
PubMed1989

The amino-acid sequence of pancreatic ribonuclease from the mole rat Spalax ehrenbergi, chromosomal species 2n = 60.

The amino-acid sequence of pancreatic ribonuclease from the chromosomal species of Spalax ehrenbergi with karyotype 2n = 60 was determined. From the comparison of the sequence with other mammalian sequences we found that Spalax diverged from the myomorph rodent branch before the divergence of the Muridae and the Cricetidae. All myomorph rodent sequences evolved faster than those of other mammals, an effect being most pronounced for the rat sequence. Spalax ribonuclease shares several amino-acid residues with other myomorph rodent species. These are not or only rarely observed outside this rodent suborder. However, there are 6 amino-acid replacements not observed earlier in pancreatic ribonucleases, and 2 other replacements and an insertion of one residue in the variable loop 15-24 are only observed in the enzyme from turtle pancreas.

Amino Acid Sequence↗
PubMed1985

The amino acid sequence of snapping turtle (Chelydra serpentina) ribonuclease.

Snapping turtle (Chelydra serpentina) ribonuclease was isolated from pancreatic tissue. Turtle ribonuclease binds much more weakly to the affinity chromatography matrix used than mammalian ribonucleases. The amino acid sequence was determined from overlapping peptides obtained from three different digests. The N-terminal amino acid sequence of the protein determined by others [E. A. Barnard, M. S. Cohen, M. H. Gold J.-K. Kim (1972) Nature (Lond.) 240, 395-398] and homology were used as additional evidence for several overlaps. The polypeptide chain consists of 119 amino acid residues. Compared to most ribonucleases the N-terminal residue, three residues in the loop near residue 71 and two residues in the loop near residue 114 are deleted, and there is one additional residue in the loop near residue 23. The half-cystines at positions 65 and 72, which form a disulfide bond in mammalian ribonucleases, are not present in turtle ribonuclease. Turtle ribonuclease differs from bovine ribonuclease at 70 of the 118 positions where both proteins have amino acid residues. Turtle ribonuclease contains no carbohydrate, although the enzyme possesses a recognition site for carbohydrate attachment in the sequence Asn-Ala-Ser (positions 76-78).

Amino Acid Sequence↗