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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Accreditation and quality assurance 3 (1998), S. 427-428 
    ISSN: 1432-0517
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The T-cell receptor (TCR) is a highly variable molecule composed of two polypeptide chains that recognize antigenic peptides in the context of major histocompatibility complex (MHC) molecules. In this study, we describe a sequence-based search for germline polymorphisms in the variable (V) gene segments of the human TCRA/D locus. Thirty different V gene segments were amplified from six to eight unrelated individuals and sequenced from low melting point agarose. Twenty-seven polymorphisms were identified in 15 V gene segments. These polymorphisms are mainly single nucleotide substitutions, but an insertion/deletion polymorphism and a single dinucleotide repeat with variable length were also seen. Of the 15 sequence variations found in the coding regions, six are silent and nine encode amino acid changes. All of the amino acid changes are found at non-conserved residues, frequently in the hypervariable regions, where they may influence MHC and/or peptide recognition. Therefore, it is possible that germline variations in TCR genes could influence an individual’s immune response, and may also contribute to susceptibility to diseases such as autoimmunity.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Chromosoma 3 (1950), S. 449-473 
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Pycnotic degeneration of neoplastic and normal nuclei of mice has been studied cytologically and cytochemically, in pieces of tissues removed some time after subcutaneous transplantation. The cytological changes in pycnosis were found to be about as they have often been described earlier: the nuclei become spherical, shrink progressively, the nucleoli become lost, the chromatin becomes homogeneous. The relative changes in total desoxyribose nucleic acid were followed by the Feulgen reaction; the methylgreen stain was used as an index of nuclei acid polymerization; the Millon reaction was used for the detection of the protein changes. In order to measure the amounts of the Feulgen and methylgreen dye, respectively the color developed by the Millon reaction within individual nuclei, the photometric microscopic method after Pollister and Ris was used, which allows the estimation of relative amounts of colored precipitates within individual nuclei of fixed and stained sections. Using these methods the nucleoprotein composition of resting nuclei of a viable tumortissue was compared with that of three pycnotic stages (Stage I, II, III) in nuclei of necrotic areas of the same tumor tissue (Sarcoma 180). In Sarcoma 180 the change from a fresh tumor cell to Pycnosis I involves loss of nearly half the protein, no significant decrease in desoxyribose nucleic acid, and depolymerisation of over half of the desoxyribose nucleic acid. Later these processes continue, and there is added progressive loss of DNA. It is pointed out that at any pycnotic stage there is a total protein equivalent to about 20 times the highly polymerised (methylgreen positive) DNA, which is the ratio found in non-pycnotic nuclei of the type from which these were derived. It is suggested that this part of the pycnotic chromatin represents the unaltered nucleoprotein. In transplanted liver nuclei pycnosis is much more rapid than in neoplastic tissue, but otherwise the two processes are similar both cytologically and chemically. The discussion points out that: a) there is no real increase in chromatin stainability in pycnotic nuclei; b) the change of shape in pycnosis may be due to lower nuclear viscosity accompanying the DNA depolymerisation; c) the highly polymerised state of the DNA may depend upon the presence of some particular protein, possibly histone; and d) that pyenosis can be interpreted as showing high proteolytic activity in the nucleus and a delayed nuclease activity.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Chromosoma 4 (1950), S. 404-428 
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The study of certain structures, like the acrosome and Nebenkern, in the developing sperms of Arvelius is facilitated by the fact that they are present in greatly enlarged dimensions in certain testicular lobes while retaining normal size in adjoining lobes. 2. The dictyosomes or Golgi bodies in the spermatocytes are stained red by the PAS treatment. They are assembled to form the similarly stained acroblast in the spermatid, and the acrosome that is finally evolved is also PAS-positive in its color reaction. All the evidence indicates that in the process of acrosome formation there is a direct utilization of dictyosomal material which is already present two cell generations earlier. 3. The substance responsible for the red staining of the dictyosomes and acrosome is a polysaccharide with a 1,2 glycol grouping. There is also direct evidence for the presence of small quantities of proteins which probably form a complex with the polysaccharides. This complex is similar or perhaps identical with a mucopolysaccharide. 4. The Nebenkern, which is a mitochondrial derivative, does not contain polysaccharides with a 1,2 glycol grouping. On the other hand, it contains considerable amounts of proteins which, in contrast to those of the acrosome, are easily digested by pepsin. The evidence does not support the suggestion, frequently made, that the acrosome and Nebenkern are closely interrelated. 5. The enzymatic nature of the acrosome and its possible role in fertilization and sterility are discussed.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Sperm nuclei within activated eggs of the clam, Spisula solidissima were found to contain a normal haploid amount of DNA while sperm nuclei in inactivated eggs of the same clam contain significantly lower amounts of DNA. 2. The DNA content of sperm nuclei within activated eggs increases to approximately the diploid amount during pronuclei formation whereas the DNA content of sperm nuclei in inactivated eggs does not show any increase. 3. The amount of DNA in spermatozoa in the testis of Spisula varies from one clam to another. Some clams have predominantly the normal haploid amount of DNA while others show significantly lower amounts of DNA in the spermatozoa in the testis. 4. The possible significance of the DNA content of spermatozoa for the activation process of the Spisula egg is discussed.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Interferometric dry mass and microspectrophotometric DNA and arginine determinations were carried out on 4000 sperm nuclei from 85 bulls. The results obtained are as follows: 1. Spermatozoa containing a constant haploid amount of DNA (3.04 × 10−9 mg.) also have a constant arginine content of 2.07 × 10−9 mg. with a DNA/arginine ratio of 1.47. 2. Spermatozoa containing variable and low amounts of DNA also have variable and usually higher amounts of arginine with a ratio of 0.95 for DNA/arginine. 3. However the dry mass of sperm nuclei with an abnormal DNA content is nearly the same as the dry mass of sperm nuclei with the normal haploid DNA content. The dry mass for each group is 7.3 × 10−9 mg. and 7.1 × 10−9 mg. respectively. 4. On the basis of the DNA, arginine and dry mass data, a protein content of 4.06 × 10−9 mg. containing 50% arginine can be computed for normal bull sperm nuclei.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microspectrophotometric studies were made on the amounts of DNA in individual spermatozoa of 21 human males with proven fertility and on 18 human males who are partners in sterile couples. The results were as follows: 1. The amount of DNA per spermatozoon of the 21 fertile males is very constant and uniform within each individual and among the 21 different individuals. The mean amount of DNA in arbitrary units is 1.22±0.005 per sperm and is approximately one-half that of human somatic cells which is 2.66±0.05. 2. In contrast to the uniformity of DNA in the sperms of fertile males, the sperms from the 18 males under examination for “suspected sterility” showed greatly varying amounts of DNA. 3. 6 of this suspected group had DNA values close to, but not exceeding that of the fertile males. But for 4 of these 6 males this normal DNA amount conformed to the clinical diagnosis that not the males, but their female partners were responsible for the infertility. The remaining 2 males had sperms with impaired motility, a manifestation which may involve a different factor than that of deviations in the amount of DNA. 4. 5 males represented a category of borderline cases in which the mean DNA was slightly lower than that of the normal group, but many individual measurements overlapped those of normal sperms. So far as the clinical diagnosis was concerned, 4 of these 5 males were on the borderline for male fertility while 1 male had been diagnosed as infertile because he had sperms with impaired motility. 5. 7 of the suspected group carried sperms with DNA in decidedly lower amounts than those of normal, fertile sperms. In 5 of these 7 males the clinical diagnosis ascribed the infertility to the males. In the remaining 2 cases where the DNA was also found to be low in the spermatozoa, no cause could be given clinically for the sterility either in the male or in the female partner. 6. These data suggest a correlation between a deficiency of DNA in the sperms and one type of male sterility, but this cannot be considered as established until further data (such as more information on the female partner) become available.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    GeoJournal 39 (1996), S. 221-227 
    ISSN: 1572-9893
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract This paper analyses the meeting between the international petroleum industry and two local communities. The building of an oil terminal in a local community is both a major event, and a generator of processes on the local level. Three different angles is used to enlighten these processes; categorised as as “place”, “people” and “mind”. The “place” analysis consentrates on the effects on population and workforce development, the “people” analysis look at the institutional and planning processes, and the “mind” analysis the effects on the feeling of local identification. The paper demonstrates that local factors are of crucial importance even for the international petroleum industry.
    Type of Medium: Electronic Resource
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  • 9
    Publication Date: 2013-03-29
    Print ISSN: 0944-1344
    Electronic ISSN: 1614-7499
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Springer
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  • 10
    Publication Date: 2013-06-14
    Print ISSN: 0944-1344
    Electronic ISSN: 1614-7499
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Springer
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