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  • 1
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. In populations of the dipteran Phryne cincta (2n = 6+XX♀, XY♂) several X-chromosomes of different structure are present. These are allocyclic in contrast to the (eucyclic) autosomes, as seen in their behaviour in mitosis and meiosis and in their varied appearance in polytene nuclei (comp. Wolf 1950, 1957). 2. The polytene autosomes (2–4 s. Pig. 7) differ from each other in easily recognizable characters and form no chromocenter. The polytene X-chromosome is always relatively much shorter than the autosomes and more or less β-heterochromatic (granular or indistinctly banded) in larvae, raised at room temperature. In larvae raised at low temperature (0–4° C) it passes through a morphogenesis, growing to normal or nearly normal length and assuming the aspect of an euchromatic element (comp. X a in Figs. 3 and 4). 3. Two stocks, characterized by different X-chromosomes, symbolized by X a and X b or a and b respectively, were chosen for the experiments. In mitosis both these X-chromosomes are rod-like, a is as long as autosome 4, b has only half its length (Figs. 1, 2a–d). 4. Just before pupation, in polytene nuclei of larvae raised at low temperature a and b are of almost equal length. They differ from each other in several inversions and in the appearance of two large α-heterochromatic bands in a (α2 and α3, Fig. 5; “α-quantum-difference”). 5. The α-bands, especially the large block α2, show a considerable intercellular variation in their relative DNA-content (measured as length of the α-element). The mean DNA-content is negatively correlated with the degree of stretching of the chromosome (Table 1). 6. In polytene nuclei of female hybrids from the crosses aaxbY or bbxaY, a and b are unpaired or incompletely paired in variable degrees (Figs. 7, 8a–e). The heterozygotic chromosome pair can be devided into 5 segments (I–V, Fig. 6), three of which are marked by clearly defined structural differences (I, III, V). 7. The pairing-segments II and IV, exhibiting an identical and parallel sequence of discs in a and b, allow six crossing-over recombinations (cb, db, eb, fb, gb, hb; comp. Figs. 9, 10). These new types of X-chromosomes occur in very different frequencies in the progeny of the hybrid ♀♀ when backcrossed to standard ♂♂ bY. The types eb and fb occur relatively rarely, while gb and hb are extremely rare (Figs. 9, 10, Table 2); in 70% of the progenies they are not present. The recombination-process is mainly restricted to pairing segment IV. 8. In a and in the crossover-chromosomes c, e, g very often a threadlike constriction appears in the region of α 2, resulting mostly in a pseudofragmentation with more or less independent location of the two chromosome parts (Figs. 3d, 8f-i, 11a). A variety of kinds of fusion between the parts and the autosomes, especially in their α-heterochromatin, is possible (Figs. 3e, 8g–i). 9. Lowering the breeding-temperature increases the duration of development, the size of the larvae, and the lengthening and euchromatization of the β-heterochromatic parts of the X-chromosomes. In the hybrids it also results in increasing the recombination rate (Table 3 and 4). 10. In the main experiments, hybrid offspring from the same parental pair, were raised at different temperatures: some individuals at high (20–26° C), others at low temperatures (2–8° C). The resulting two series of imagos were kept in optimal or room temperatures (14–22° C). The female progeny of 23 hybrids raised at elevated temperature and of 27 hybrids raised at low temperature, i.e. 1766 and 2102 X-chromosomes respectively, have been tested (Table 5, Fig. 12). No or only little recombination occurred in hybrids raised at 20–26° C (mean = 2.4%) in contrast to their sisters raised at 2–8° C, which gave a relative high frequency (mean = 18,2%). 11. In these cases only the first egg batches of each hybrid ♀ have been evaluated. Later progeny exhibits a reduction in crossing-over frequency in cold-raised hybrids with growing age. The mean rate of recombination of 14 hybrids is lowered from 16,6% in the first to 7,1% in the following progeny (n=1813; Table 6, Fig. 15) presumably as a consequence of keeping the imago in higher temperature. 12. The results from several larger groups of cold-raised sister hybrids more or less clearly demonstrate a bimodal distribution of recombination values (Fig. 13) suggesting a difference in recombination potentiality between the two X-chromosomes in the mother of the hybrids. Some data indicate the recombination rate in the X-chromosome as negatively correlated with the rate of development (Table 7). 13. The Mendelian ratio, 1∶1, of the non-recombinant types, ab and bb, is found in the progeny of the warm-raised hybrids (1769∶1778). This ratio is shifted considerably in favour of type ab in the case of low temperature hybrids (1996∶1626). In the recombinant types, cb and db, the ratio is always markedly shifted in favour of cb, irrespective of temperature (712:343). There must exist a causal relation between the Mendelian anomaly and the recombination process the nature of which is yet unknown. 14. The temperature at which a larva is raised effects both the frequency of crossing over and the stretching and euchromatization of β-heterochromatin in the polytene X-chromosome. This parallele suggests that structural changes comparable to those in the polytene chromosomes are induced by low temperature in meiotic chromosomes as well, and that these changes are responsible for the effect on the crossing-over frequency. These changes, which are reversible by age or temperature, are supposed to cause the extention of the “effective pairing” (as in euchromatic segments) on β-heterochromatic elements, which normally are unpaired. 15. The so-called “α-quantum-difference”, i.e. the difference in the amount of α-heterochromatin (or in the “relative DNA-content”) between the X-chromosomes is considered to be causally related to the crossing-over process (“α-differential-effect”). By way of a potential function it effects crossing over not only within the “α-differential” tetrad but also crossing over in non-homologous and unrelated pairs of chromosomes in the same meiotic cell. 16. This hypothesis was ascertained by two independent inversions in autosome 2 (In 2a and In 2b, Fig. 16) which permitted to test the influence of the “α-quantum-difference” in the X-chromosomes on crossing over in the autosome. In preliminary studies the progenies of 8 females (ab, bb, cb) and 3 males (aY, cY) of the heterozygous F1 backcrossed to homozygous b-stock have been investigated. In the progeny of the males only the parental combinations in autosome 2 were found. In the test cross progeny of the females the two expected types of recombination appeared (with only one inversion, In 2a or In 2b), but there existed a very high difference in linkage between bb- ♀♀ on the one side (3.6% crossing over) and ba- and bc-♀♀ on the other (40.2% crossing over).
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  • 2
    ISSN: 1432-1041
    Keywords: adverse drug reactions ; psychotropic drugs ; intensive drug monitoring ; organized spontaneous reporting ; psychiatric patients ; adverse reaction frequency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A system for monitoring adverse drug reactions (ADR) in psychiatric inpatients was introduced in psychiatric hospitals in the FRG in May 1979. It consists of intensive drug monitoring (IDM) and a so-called “organized spontaneous reporting system” (OSR). ADR are rated separately according to impact on therapy and probability of causal relationship. With IDM all ADR (Grades I–III) are assessed in a randomly selected sample of inpatients. With OSR only ADR leading to discontinuation of the drugs in question (=ADR Grade III) are assessed. In 406 drug-treated inpatients monitored by IDM in the psychiatric hospitals of Berlin and Munich from May 1979 to Dec. 1981, ADR were observed in 60,4%. In 15% of IDM-patients ADR led to discontinuation of the drugs in question; with OSR the relative frequency of these Grade III ADR was 9,0% in 5096 patients monitored throughout the entire period. Life-threatening events were observed in 1,2% of patients undergoing IDM as well as 1.2% of those undergoing OSR. The most frequently observed ADR by IDM were sedation, extrapyramidal signs, disturbances of the autonomic nervous system and increase in transaminases, and by OSR Parkinsonism, akathisia, sedation, toxic delirium and increased transaminases. The relative frequency of Grade III ADR was similar for neuroleptics and antidepressants (5,4% and 5,3% in OSR); a very low relative frequency of ADR Grade III was found for tranquilizers and hypnotics (0,7% and 0,2%). Methodological aspects of this drug monitoring system are discussed in the light of current literature.
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  • 3
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Newborn screening for biotinidase deficiency has identified children with profound biotinidase deficiency (〈10% of mean normal serum activity) and those with partial biotinidase deficiency (10%–30% of mean normal serum activity). Children with partial biotinidase deficiency and who are not treated with biotin do not usually exhibit symptoms unless they are stressed (i.e., prolonged infection). We found that 18 of 19 randomly selected individuals with partial deficiency have the transversion missense mutation G1330〉C, which substitutes a histidine for aspartic acid444 (D444H) in one allele of the biotinidase gene. We have previously estimated that the D444H mutation results in 48% of normal enzyme activity for that allele and occurs with an estimated frequency of 0.039 in the general population. The D444H mutation in biotinidase deficiency is similar to the Duarte variant in galactosemia. The D444H mutation in one allele in combination with a mutation for profound deficiency in the other allele is the common cause of partial biotinidase deficiency.
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  • 4
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Biotinidase deficiency is an autosomal recessively inherited disorder in the recycling of the vitamin biotin. The most common mutation that causes profound biotinidase deficiency in symptomatic individuals is a deletion/insertion (G98:d7i3) that occurs in exon B of the biotinidase gene. We now report the second most common mutation, a C-to-T substitution (position 1612) in a CpG dinucleotide in exon D of the biotinidase gene. This mutation results in the substitution of a cysteine for arginine538 (designated R538C) and was found in 10 of 30 symptomatic children with profound biotinidase deficiency, 5 of whom also have the G98:d7i3 mutation. This mutation was not found in DNA samples from 32 individuals with normal biotinidase activity, but was found in one individual with enzyme activity in the heterozygous range. This mutation was not detected in 371 randomly selected, normal individuals using allele-specific oligonucleotide hybridization analysis. Aberrant biotinidase protein was not detectable in extracts of fibroblasts from a child who is homozygous for the R538C mutation, but was present in less than normal concentration in identical extracts treated with β-mercaptoethanol. Because there is no detectable biotinidase protein in sera of children who are homozygous for the R538C mutation and in combination with the deletion/insertion mutation, the R538C mutation likely results in inappropriate intra- or intermolecular disulfide bond formation, more rapid degradation of the aberrant enzyme, and failure to secrete the residual aberrant enzyme from the cells into blood.
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  • 5
    ISSN: 1432-2242
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 6
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Summary A method, using seismic data, is presented for the mapping of the irregular boundary of an elastic half-space. It furnishes the shape of the corrugations in terms of the measured displacement field generated by plane dilatational or shear waves reflected from the boundary.
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  • 7
    ISSN: 1432-0630
    Keywords: PACS: 81.15.Fg; 64.60.My; 61.66.Dk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Fabrication of metastable binary solid state film mixtures with continuously variable composition by asymmetric cross-beam PLD is demonstrated. In this technique, the materials are mixed directly in the intersection region of colliding plasmas of individual target materials. This technique can be advantageous for synthesis of solid state quasi-solutions of partially miscible materials, where one can expect interesting mechanic properties and magnetic transformations.
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  • 8
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract True accessory nuclei with the characteristic “double” membrane structure have been observed in the oocytes of the dipterans (Nematocera) Phryne cincta and P. fenestralis. They seem to arise from proliferations of the nuclear membrane. Although they often cling to the nucleus after their formation, they differ from it in certain structural details; their inner membranes are less electron-dense, and they have a greater frequency of pores.
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  • 9
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Investigations were made of the scattering behaviour of polystyrene in the thermodynamically “bad” solvent cyclohexane between precipitation-temperature andϑ-temperature. At theϑ-point and close to it the behaviour of a statistically coiled chain molecule is found. Belowϑ-temperature an aggregation is beginning. Just above precipitation-temperature the molecular weight corresponds to an entanglement of two chain molecules. Appearance of compact polymer coils could not be noted at this temperature. The influence of the chain crosssection upon the scattering curve is considerable as the crosssection is not much smaller than the persistence length. Nevertheless, the persistence length (a=12.2 Å) may be determined from the transition point between the ranges roughly proportional to 1/(2ϑ)2 and 1/(2ϑ) as the break within the transition range is very distinct on account of the great number of persistence lengths per molecule.
    Notes: Zusammenfassung Es wurde das Streuverhalten von Polystyrol im thermodynamisch „schlechten” Lösungsmittel Cyclohexan zwischen Entmischungstemperatur undϑ-Temperatur untersucht. Beim ϑ-Punkt und nahe dabei liegt das Verhalten eines statistisch verknäuelten Fadenmoleküls vor. Unterhalb derϑ-Temperatur beginnt eine Aggregation. Knapp oberhalb der Entmischungstemperatur entspricht das Molekulargewicht etwa einer Verhängung zweier Fadenmoleküle. Ein Auftreten von kompakten Polymerknäueln ist bei dieser Temperatur nicht festzustellen. Der Einfluß des Fadenquerschnitts auf die Streukurve ist beträchtlich, da der Querschnitt nicht viel kleiner als die Persistenzlänge ist. Trotzdem läßt sich die Persistenzlänge (a=12,2 Å) aus dem Übergangspunkt zwischen den etwa 1/(2ϑ)2 und 1/(2ϑ) proportionalen Bereichen bestimmen, da der Knick im Übergangsbereich infolge der großen Anzahl von Persistenzlängen pro Molekül sehr ausgeprägt ist.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 94 (1963), S. 373-375 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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