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U Schindler

Publications and source records attributed to U Schindler.

54 records · Page 3Linked to original sources
PubMed1991

An Arabidopsis thaliana G-box-binding protein similar to the wheat leucine zipper protein identified as HBP-1.

G-box (CCACGTGG) like sequences are present in a variety of plant promoters and in many cases they have been demonstrated to be required for maximal expression of the corresponding gene. A nuclear protein, GBF, interacts specifically with the G-box motif of several RBCS and CAB promoters. Here we describe the isolation of a cDNA from Arabidopsis thaliana that encodes a protein, designated GBF-1, with DNA binding properties similar to GBF. GBF-1 is characterized by a basic/leucine zipper motif which is strikingly similar to the wheat protein identified as HBP-1. GBF-1 also interacts with an oligonucleotide derived from the wheat histone 3 promoter containing the binding site (hexamer, TGACGT) for HBP-1. This DNA element also contains a G-box-like motif, modification of which results in loss in binding of GBF-1.

Amino Acid Sequence↗
PubMed1990

Photoregulated gene expression may involve ubiquitous DNA binding proteins.

Several promoter elements have previously been shown to influence the expression of the cab-E gene in Nicotiana plumbaginifolia. Here we demonstrate, by electrophoretic mobility shift and methylation interference assays, that a complex pattern of protein-DNA interactions characterizes this promoter. Among the multiple proteins identified, we focused on five different factors which either occupied important regulatory elements and/or were present in relatively large amounts in nuclear extracts. All of these proteins were distinguished on the basis of their recognition sequence and other biochemical parameters. One, GBF, interacted with a single sequence within the cab-E promoter homologous to the G-box found in many photoregulated and other plant promoters. A second factor, GA-1, bound to the GATA element which is located between the CAAT and TATA boxes of the cab-E and all other LHCII Type I CAB promoters. GA-1 also interacted in vitro with the I-boxes of the Arabidopsis rbcS-1A promoter and the as-2 site of the CaMV 35S promoter. Two other factors, GC-1 and AT-1, bound to multiple recognition sites localized within the GC-rich and AT-rich elements, respectively. GT-1, a protein which interacts with promoters of other light-regulated genes, bound to seven distinct sites distributed throughout the cab-E promoter.

Base Sequence↗
PubMed1990

The plant G box promoter sequence activates transcription in Saccharomyces cerevisiae and is bound in vitro by a yeast activity similar to GBF, the plant G box binding factor.

G box and I box sequences of the Arabidopsis thaliana ribulose-bisphosphate-1,5-carboxylase small subunit (RBCS) promoter are required for expression mediated by the Arabidopsis rbcS-1A promoter in transgenic tobacco plants and are bound in vitro by factors from plant nuclear extracts termed GBF and GA-1, respectively. We show here that a -390 to -60 rbcS-1A promoter fragment containing the G box and two I boxes activates transcription from a truncated iso-1-cytochrome c (CYC1) gene promoter in Saccharomyces cerevisiae. Mutagenesis of either the rbcS-1A G box or both I box sequences eliminated the expression mediated by this fragment. When polymerized, I box oligonucleotides were also capable of enhancing expression from the truncated CYC1 promoter. Single-copy G box sequences from the Arabidopsis rbcS-1A, Arabidopsis Adh and tomato rbcS-3A promoters were more potent activators and were used in mobility shift assays to identify a DNA binding activity in yeast functionally similar to GBF. In methylation interference experiments, the binding specificity of the yeast protein was indistinguishable from that obtained with plant nuclear extracts.

Base Sequence↗
PubMed1989

Pre-clinical evaluation of cognition enhancing drugs.

1. The need of the treatment of cognitive impairment due to aging or dementia has led to the search for potential cognition enhancing drugs. The various compounds presently under development represent an alternative to the cholinomimetic therapy and include new chemical entities as well as piracetam and its newer analogs. 2. Recent results from pre-clinical evaluation of the effects on learning on memory are summarized. Emphasis is put on learning and memory experiments under normal and pathological conditions. Most of the nootropics attenuate experimental amnesias induced by scopolamine, cycloheximide, ECS, hemicholinium-3 or forebrain ischemia. These findings suggest that the nootropics may be influencing a common mechanism underlying the amnesias. 3. Biochemical data suggest a potential cholinergic neuronal activity of some of the piracetam analogs. They increase high-affinity choline uptake, and antagonize scopolamine- and ECS-induced decreases in acetylcholine concentrations in the hippocampus. The mode of action of these and all other nootropic compounds, however, is still not known. 4. Despite the interesting results from learning and memory studies and from biochemical investigations, the clinical relevance of these results for amelioration of the cognitive impairment in humans remains to be proven for most of the compounds.

Amnesia↗
PubMed1989

Ornithine cyclodeaminase from octopine Ti plasmid Ach5: identification, DNA sequence, enzyme properties, and comparison with gene and enzyme from nopaline Ti plasmid C58.

Octopine and nopaline are two arginine-derived opines synthesized in plant cells transformed with octopine or nopaline plasmids. Utilization in Agrobacterium tumefaciens is mediated by Ti plasmid regions called occ or noc (octopine or nopaline catabolism), and recent experiments showed that noc in pTiC58 codes for a pathway from nopaline to L-proline. The last enzyme is ornithine cyclodeaminase (OCD), an unusual protein converting L-ornithine directly into L-proline. We investigated whether octopine plasmid pTiAch5 also harbors a gene for OCD. The results revealed an ocd gene which is induced by octopine and maps in the occ region. DNA sequence analysis and comparison with the gene from pTiC58 showed that the two genes are related (69% homology in DNA and deduced amino acid sequence), and antiserum against OCD(C58) also reacted with OCD(Ach5). The enzyme activity was characterized, and a comparison with OCD(C58) showed that the properties are similar, but not identical. Differences were detected in the regulation of enzyme activity by L-arginine and L-proline and in the response to varying ratios of NAD+/NADH. It is proposed that this reflects different mechanisms for integration of opine catabolism into general metabolism.

Amino Acid Sequence↗
PubMed1988

Ornithine cyclodeaminase from Ti plasmid C58: DNA sequence, enzyme properties and regulation of activity by arginine.

Nopaline, an abundant opine in plant cells transformed with nopaline-type Ti plasmids, is catabolized in Agrobacterium by three Ti-plasmid-coded steps via arginine and ornithine to proline. The last enzyme, ornithine cyclodeaminase (OCD), converts ornithine directly into proline with release of ammonia. We describe the DNA sequence of the ocd gene from Ti plasmid C58, antiserum against an OCD fusion protein overexpressed in Escherichia coli, induction and identification of the gene product in Agrobacterium and enzymatic properties of the protein. The DNA sequence suggests a soluble protein with a stretch of some homology with ornithine carbamoyltransferases from other bacteria. OCD activity is subject to substrate inhibition, is stimulated by NAD+ (presumably acting as a catalytic cofactor) and is regulated by L-arginine which has pronounced effects on the optima for pH and temperature and on the Km for ornithine. The regulation of OCD activity by L-arginine is discussed as part of the mechanisms which integrate the pathway of Ti-plasmid-coded opine utilization with general metabolism in Agrobacterium.

Amino Acid Sequence↗
PubMed1985

[Diagnosis of primary hyperparathyroidism by selective determination of parathyroid hormones].

Due to a hypercalcaemia and changeably appearing hypercalciuria 13 patients with relapsing urolithiasis were under suspicion of a primary hyperparathyroidism. After selective sounding and withdrawal of blood from the cervical veins in all cases the determination of parathormones was performed and always an increased activity of parathormones was found. The exploration of the cervical region carried out could in 11 performed operations in 8 cases prove an adenoma and in 3 cases a hyperplasia as cause of hyperparathyroidism. A localization of the suspected adenoma was in 5 cases possible in combination with the angiography of the thyroid gland. By equally high activity in 3 cases no clear evidence was possible. An improvement of the diagnostics of localization might be achieved by supraselective sounding of the veins. On principle the authors recommend to perform a selective determination of parathormones before operation, which in case of need is to be supplemented by a selective angiography of the thyroid gland.

Adult↗
PubMed1984

[Use of rapid microscopic sputum diagnosis in clinical practice].

A total of 222 unselected expectorated sputum samples obtained from patients with various diseases of the respiratory tract was examined microscopically following the method of Murray and Washington. Based on standardized criteria of evaluation of gram-stained smears direct microscopic examination is a simple and reliable method providing primary information, and can be recommended for bedside diagnostics.

Asthma↗
PubMed1983

[Symptomatology and therapy of atypical perforations of gastrointestinal ulcers].

Starting from three patients, we observed the last three years, we discuss the pathogenesy and the symptomatology of different kinds of perforated gastroduodenal ulcers. We present a classification of these different kinds of adequate to the anatomical and pathological aspects and demonstrate the essential characteristics. We conclude with some aspects of nonsurgical treatment, which is possible in some few cases.

Diagnosis, Differential↗
PubMedDate not supplied

Influence of severe hypercapnia upon cerebral cortical metabolism, CSF electrolyte concentrations and EEG in the cat.

The interconnections between EEG, intermediary and energy metabolism of the brain cortex and CSF potassium level are studied during severe hypercapnia in anaesthetized, artificially ventilated cats. Hypercapnic animals were ventilated with 40 to 50% to CO2 in oxygen. During severe hypercapnia the EEG becomes isoelectric. The CSF potassium concentration is raised and the changes in metabolism suggest an acidosis-induced inhibition of phosphofructokinase and, probably, of hexokinase. The energy charge potential remains unchanged whereas the cortical ATP concentration increases slightly. It is assumed that the changes in P-creatine and creatine levels are related to the pH-dependency of creatine phosphokinase. Recovery animals were ventilated with 40% CO2 in O2 and subsequently with room air. After termination of CO2 inhalation the EEG reappears, the CSF potassium concentration normalizes, and the inhibition of the glycolytic enzymes disappears. The energy charge potential shows a small decrease. It is not possible to trace back the disappearance of the EEG to only one of the recorded parameters. Cortical P-creatine levels, CSF potassium concentration, changes in membrane permeability and cortical amino acid concentrations are considered in this context.

Animals↗
PubMedDate not supplied

Is screening of metastases based on symptoms effective in breast cancer patients?

This study was initiated to evaluate if the follow-up of breast cancer patients based only on symptoms is effective. 757 patients participated in the study. They filled out a questionnaire which asked for specific and non-specific symptoms of metastases which was developed by a team of expert oncologists. Surprisingly 76% of all patients complained of symptoms. 129 patients were therefore screened, but only 5% had metastases. 31 patients developed metastases during the study, most of whom did not have specific symptoms. Therefore follow-up with the aim of detecting metastases cannot be based on symptoms alone.

Breast Neoplasms↗