Biomedical subjects
Publications and source records attributed to B Otto.
Now that information on trefoil domain structure is available from X-ray crystallographic and nuclear magnetic resonance spectroscopy studies, we can begin to understand the functions of these unusual protein motifs.
Interferons / An overview on the state of basic research with special regard to interferon-gamma Interferons are multifunctional glycoproteins with a broad range of antiviral, antiproliferative and immunoregulatory effects on the target cell. This review deals with the basics as well as with more recent developments in interferon research. A historic overview of 35 years of interferon research since the discovery of interferons by Isaacs and Lindenmann in 1957 introduces the most important milestones in this field and appreciates the work of the participating researchers. A brief description of the classification of interferons based on different tissue sources, different antigenic properties and different induction behaviour is made. The main part of this review focuses on human interferon-gamma. We discuss recent work on the structure-function relationship of interferon-gamma. The interferon-gamma receptor and its role in signal transduction is another part of this paper. The structure and length of the C-terminal region of interferon-gamma seems to be important for receptor binding and expression of biological activities. A conservative estimate is that the family of IFN-activated genes numbers 15-20 in most cells.
We have previously shown that heat-shock in the dark evokes photomorphogenesis-like effects and circadian rhythmicity at the level of mRNAs when applied to emerging pea plantlets during several consecutive days [15]. Here we extend these findings by showing that a temperature shift to 10 degrees C above average and a single heat-shock are sufficient for induction of circadian rhythmicity and changes in morphogenesis. The maximum response to a single heat-shock occurs at days 2 to 3 after sowing indicating additional developmental control of the response. An increasing number of heat-shock treatments intensifies the morphogenetic effect. The heat-shocked plantlets have an elevated level of the xanthophyll lutein in the dark. Upon illumination of heat-shocked plantlets accumulation of chloroplast pigments as well as that of individual thylakoid membrane proteins and their corresponding mRNAs occur much faster than in the etiolated controls. This is reflected in an accelerated formation of grana stacks. Therefore, heat-shock seems to evoke a responsiveness of plantlets similar to that obtained earlier by other authors using pre-illumination. The working hypothesis is put forward that induction or synchronization of circadian rhythmicity by either light or heat-shock might be sufficient to explain the observed morphogenetic changes.
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In this essay a position is taken concerning the reproaches against Bruno Bettelheim. Shortly after his death grave reproaches were risen by a former client of him. The reproaches cannot be refuted. But they have to be discussed in connection with Bruno Bettelheim's activities at the Orthogenic School of Chicago. By this example the authors tries to demonstrate the problem of over-taxing in psychiatric activities.
The biological function of the 20 C-terminal amino acids of human interferon-gamma (IFN-gamma) was examined by recombinant DNA methodology. Six truncated IFN-gamma analogues were produced by modification of the 3' end of the coding sequence of the cloned gene, insertion into a vector with the trc promoter and expression of the recombinant IFN-gamma analogue genes in Escherichia coli strain JM 105. The IFN-gamma analogue proteins were shortened by 10 (C-10L), 11 (C-11, C-11L), 14 (C-14L), 19 (C-19L) and 20 (C-20) amino acid. Four of these constructs were modified to have a C-terminal leucine. The expression rates of precipitating IFN-gamma variants in E. coli cells (wild type, C-10L, C-11, C-11L) amount to 35-40% of the total protein, in contrast to 14-21% for the mainly soluble ones (C-14L, C-20). The variant C-19L has an exceptional position in its solubility behaviour with a nearly 1:1 distribution between its soluble and insoluble form by an expression rate of 8%. The purification protocol of the insoluble variants contains a denaturing and a renaturation step. The characteristic step for purification soluble IFN-gamma is HPLC cation-exchange chromatography. The antiviral activities of the variants lacking 14 or more amino acids are less than 2% of the wild-type activity. The variants C-10L, C-11 and C-11L show higher biological activities than wild-type IFN-gamma. The most active variant, C-10L, with leucine as the last C-terminal amino acid, has a fourfold higher specific antiviral activity (A549 cells, encephalomyocarditis virus). Removal, but not replacement of the leucine, represented by the variant C-11, reduces the biological activity compared with variant C-10L. The activity of C-11 is, nevertheless, higher than in the wild type. Comparing the secondary structures, as judged by CD analyses, no significant differences for C-10L, C-14L and C-20, compared with wild type, are observed. Also, all molecules, including the wild-type protein, exist as dimers under physiological conditions. There is a correlation between the grade of truncation and the pI values, which range from pI = 10.4 (wild type) to pI = 8.0 (C-20). The variant C-10L demonstrates a higher temperature stability (tm = 55 degrees C) compared with wild type (tm = 53 degrees C). Perhaps this higher stability will result in a longer half-life in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)
Dark-grown pea seedlings exposed to cyclic heat shocks or daily temperature changes undergo a morphogenetic development similar to that induced by far red light. The morphological changes observed include expansion of the leaves, shortening of the stems and opening of the hooks. Compared with control etioplasts, plastids of heat-treated seedlings are as large as fully mature chloroplasts and contain well developed, unstacked membranes. These morphogenetic changes correlate with elevated levels of SSU and LHCP mRNAs which, under these conditions, fluctuate in a circadian manner. In contrast, the ELIP mRNA remains under strict light control and shows circadian fluctuations only if the plants are exposed to a short period of illumination. We propose that periodic temperature changes, like light treatment, might serve as a 'Zeitgeber' signal for circadian rhythm. The data indicate a correlation between the existence of circadian oscillations and morphogenetic development.
The cDNA coding for human interferon gamma contains approximately 600 basepairs not translated sequence with 4 adenine/thymidine (AT)-rich clusters at its 3'end. The influence of this sequence on the expression of recombinant human Interferon gamma in Escherichia coli was investigated. Removal of the non-translated sequence and especially of the AT-rich clusters yielded an increase in expression of interferon gamma from 10 to 40% of total protein. These results may also be important for the production of other recombinant human proteins with similar 3' sequences in their cDNA.
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The carnitine content of semen from azoospermic subjects and subjects with either impaired motility or forward progression is reported. Within the azoospermic group, the values were not significantly different between those with testicular failure or obstruction. The patients with impaired motility (less than 40%) or impaired forward progression (less than 3) had a lower mean seminal carnitine content than those with good motility and forward progression (P less than 0.05). Seminal carnitine concentration was not an index of epididymal patency and could not be regarded as useful for locating the level of obstruction in the epididymis. Since carnitine plays an important role in the maturation process when sperm acquire motility, it would seem that seminal carnitine might be an indicator of epididymal dysfunction.
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Recombinant Escherichia coli-derived human interferon-gamma (rIFN-gamma) was given to a total of 20 patients by iv bolus injection at various doses once a week for 4 weeks. The sera obtained 7-10 days after the final injection were analyzed for antibodies against both rIFN-gamma and natural human IFN-gamma. Biological assays demonstrated that the postinoculation sera of the patients did not neutralize the antiviral activities of either rIFN-gamma or natural human IFN-gamma. Enzyme-linked immunosorbent assay showed that no detectable antibodies against rIFN-gamma were elicited. These results indicate that this rIFN-gamma preparation is not a potent antigen and may be suitable for longer-term clinical trials and applications in the future.
The genes for several human interferons (IFN) alpha, of IFN beta and IFN gamma have been cloned and expressed in bacterial cells. Recombinant interferons have been purified from these cells and shown to be as biologically active as their natural counterparts. The expression systems, purification schemes and the biochemical properties of these interferons are discussed.