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Biomedical subjects

A Spielmann

Publications and source records attributed to A Spielmann.

At least 19 recordsLinked to original sources
PubMed1995

2-micron vectors containing the Saccharomyces cerevisiae metallothionein gene as a selectable marker: excellent stability in complex media, and high-level expression of a recombinant protein from a CUP1-promoter-controlled expression cassette in cis.

We have constructed 2-micron-based yeast expression vectors containing a copy of the metallothionein (CUP1) gene of Saccharomyces cerevisiae as a semi-dominant, selectable marker. When used for the expression of the thrombin inhibitor hirudin, originally derived from the leech Hirudo medicinalis, these vectors displayed the following characteristics. (1) In the presence of copper salts, they were mitotically more stable than similarly designed control vectors lacking the CUP1 gene. In copper-sensitive host strains, the apparent plasmid stability was 100%, even in complex media and during fed-batch fermentation for an extended period of time. (2) Use of the CUP1-stabilized plasmids improved the production of hirudin by both copper-sensitive and copper-resistant hosts. The highest hirudin titers were obtained with a delta CUP1 host. (3) Copper selection resulted in a moderate increase in average plasmid copy numbers (up to two-fold) as assessed by measuring hirudin expression from a constitutive promoter (GAPFL). This effect was most noticeable if the vector showed an asymmetric segregation pattern (i.e., high rates of plasmid loss in the absence of copper). (4) The CUP1 marker proved particularly useful in combination with a CUP1-promoter-controlled expression cassette on the same plasmid. In such a set-up, the rates of transcription of the heterologous protein and that of the selectable marker are tightly linked. Therefore, an increase in selective pressure directly provokes an increase in product yields. In a copper-sensitive host strain, this plasmid design allowed for the production of very high amounts of biologically active hirudin. Our results clearly establish the utility of the CUP1 marker in the construction of stable yeast expression vectors.

Carrier Proteins↗
PubMed1994

Analysis of the 22 kbp long psbD-psbC gene cluster of Euglena gracilis chloroplast DNA: evidence for overlapping transcription units undergoing differential processing.

The clustered genes psbD and psbC covering together close to 22,000 nucleotides contain ten and eleven exons, respectively. The corresponding translation products, i.e, Photosystem II core 34 kDa (D2) protein and the CP43 chlorophyll binding protein are highly conserved. Introns vary in length from 305 to 4144 nucleotides. The two genes have about 900 nucleotides in common including an intron. To obtain stable mRNAs of about 1400 (psbD) and 1500 (psbC) nucleotides the pre-transcripts must undergo differential processing and/or splicing events within the overlapping region.

Amino Acid Sequence↗
PubMed1993

Cloning and sequencing of a corn (Zea mays) nuclear gene coding for the chloroplast specific catalytic subunit of ferredoxin-thioredoxin reductase.

We determined the complete nucleotide sequence of a cDNA clone encoding the smaller, catalytic subunit of ferredoxin-thioredoxin reductase from corn chloroplasts. The translated protein sequence, representing a subunit of 12.9 kDa shows 80% identity with the protein sequence from spinach and contains seven Cys residues all at conserved positions.

Amino Acid Sequence↗
PubMed1991

Effects of Tnt1 tobacco retrotransposon insertion on target gene transcription.

The effects of Tnt1 retrotransposon insertion on nitrate reductase (NR) gene transcription have been analyzed in three NR-deficient insertional, mutants of Nicotiana tabacum. In the three mutants, named h9-Nia4, h9-Nia5 and h9-Nia6, Tnt1 was inserted into exon 3, exon 2 and exon 1 of the nia2 NR alloallelle, respectively. The mutants h9-Nia4 and h9-Nia6, which contained Tnt1 insertions that were oriented opposite to the direction of nia2 gene transcription, expressed chimaeric nia2-Tnt1 RNAs, respectively 12 kb and 10 kb long. The size observed in h9-Nia6 was close to the expected size for a full-length hybrid transcript starting and ending under the control of nia2 signals (about 9 kb). The larger transcript found in h9-Nia4 was shown to be due to a failure to splice the nia2 intron 2. The mutant h9-Nia5, which contained a Tnt1 insertion oriented in parallel with the direction of nia2 transcription expressed two truncated nia2-Tnt1 RNAs, 2 kb and 6.7 kb long. These transcripts arose from termination in the long terminal repeats (LTRs) of Tnt1. Since no full-length hybrid RNA was detected, we suggest that Tnt1 carries efficient termination signals, which are more efficiently recognized in the 3' LTR than in the 5' LTR.

Base Sequence↗
PubMed1990

[Vertical and tortional deviations in early strabismus].

The occlusion of one eye may trigger two types of deviation: 1) Heterophorias: the occluded eye deviates towards a horizontal, vertical or torsional abnormal position of rest. Fusion keeps the eyes straight during binocular fixation. 2) Dissociated deviations, horizontal (DHD), vertical (DVD), torsional (DTD): they are found in infantile strabismus. The deviation without fixation is always smaller than the deviation of the occluded eye. The more typical cases are the ones where the position of rest without fixation is an orthoposition. Normal binocular vision is lacking. Most of the time, an alternant neutralisation is found: the occlusion deviation is not the return of the occluded eye to an abnormal position of rest. The deviation is caused by a disequilibrium of binocular retinal stimulations. Horizontal and vertical deviations are easy to study. It is not the case in dissociated torsional deviation (DTD) where the incyclotorsion does not exist when fixation is absent. An indirect proof of extorsion is given by the study of horizontal and vertical deviations determined in the cardinal position of gaze. Extorsion of the globus leeds always to abnormal actions of the recti. This give a typical synoptometer chart which is found in any extorsion whatever its origins: paralysis, alphabetic patterns or infantile strabismus. Dissociated extorsions are always associated with a bilateral elevation in the primary position. Dissociated deviations are found in infantile strabismus with the other dissociations phenomenon such as nystagmus, optokinetic nystagmus asymmetry, fixation in adduction preference (and incyclotorsion).

Accommodation, Ocular↗
PubMed1990

[Diurnal correlation of criminal behavior].

In order to study the correlation between criminal acts and time of day we analyzed reports of the Federal Police Department in Salzburg covering 2 months as well as our own psychiatric expert-opinius in cases of robbery and homicide. Offences against property have the same day-time rhythm as does regular labour. Alcoholic intoxication hardly occurs with offences against property, although the activity of burglars goes over into the early hours of night. Aggressive offences are commonly accompanied by alcoholic intoxication, they are mainly observed at night. Less aggressive offences such as maltreatment or fighting generally occur during the late afternoon until midnight. Whereas aggressive offences of alcoholized persist throughout later hours of the night. The delinquency of robbery and homicide continues into the early hours of the morning. In cases of homicide there are differences concerning the individual conflict-situation. Homicides in connection with family tragedies or partnership conflicts usually occur during the afternoon or the early evening and show just a minor connection with alcoholization. Homicides in the course of primitive conflicts appear highly correlated to alcoholization and to the night hours. In cases of homicide of mental-patients there is no general connection with alcoholization nor can there be seen a day-time correlation.

Alcoholic Intoxication↗
PubMed1990

[The role of ozone within the scope of the "Figurella Program"].

The method given by the slimming institute "Figurella International", to lose weight without applying chemistry or dieting, is scrutinized critically. The ozone treatment, one of the compounds of the method, proves to be useless. To overcome the general problem caused by photochemical oxidants the company should be set under pressure to stand back from producing ozone, which proves to be a major air pollutant but not to have any effect on the result of the slimming programme.

Austria↗
PubMed1989

Tnt1, a mobile retroviral-like transposable element of tobacco isolated by plant cell genetics.

Transposable elements can be identified by their ability to induce mutant alleles at new loci. The retrotransposon family is thought to transpose through an RNA intermediate and has many similarities to vertebrate proretroviruses. In plants, retrotransposons have been described in maize, Arabidopsis and wheat, and non-viral retroposons in maize. Most of these elements, however, have been found as non-mobile integrated units. Here, we report the isolation of the first tobacco (Nicotiana tabacum) transposable element, Tnt1, which seems to be the most complete mobile retrotransposon characterized in higher plants. Tnt1 has been isolated after its transposition into the nitrate reductase (NR) structural gene of tobacco, and transposition events have been detected through in vitro selection of spontaneous NR-deficient (NR-) mutant lines in cell cultures derived from tobacco mesophyll protoplasts. Tnt1 is 5,334 nucleotides long, contains two 610-base-pair-long terminal repeats and a single open reading frame of 3,984 nucleotides. Comparison of the Tnt1 open reading frame coding potential with those of the Drosophila melanogaster copia retrotransposon, yeast Ty retrotransposon, and vertebrate proretroviruses revealed that Tnt1 is closely related to copia and carries all the functions known to be required for autonomous transposition by reverse transcription.

Alleles↗
PubMed1988

Bilateral vertical retraction syndrome in horizontal bilateral Duane's syndrome.

In the cases of vertical retraction syndromes previously reported in the literature, the "leash effect" of vertical recti was responsible for a limitation of motility and for retraction in up- or down-gaze. This vertical retraction syndrome mimics Duane's syndrome and benefits from recession of the taut vertical recti. In the case reported, another mechanism had led to vertical retraction syndrome. In a bilateral horizontal Duane's syndrome, the physiological co-contraction of abnormally short horizontal recti in vertical gaze was responsible for vertical retraction syndrome and even for a positive vertical forced duction test. The vertical motility was returned to normal by recession of the four horizontal recti.

Child, Preschool↗