Buchbesprechungen

Morris, C. J. O. R.; Morris, P.: Separation methods in biochemistry. London, Sir Isaac Pitman & Sons Ltd., 1964, 887 S., 155 Abb., Leinen, £ 5, 15 s. Reviewed by H. Wolffgang.

Neuman, M.: Vade-mecum des antibiotiques et agents chimiothérapiques anti-infectieun. Paris, Librairie Maloine G. Doin et Cie Editeurs, 1962, 410 S., 8 Abb.; 15 Tab., Karton. 40,00 NF. Reviewed by Thren.

Umbreit, W. W.: Modern microbiology. San Francisco und London, W. H. Freeman and Company, 1962, 507 S., 307 Abb., Leinen, 48 s. Reviewed by H. J. Müller.

Gold, V.: pH-Measurements. Their theory and practice. London, Methuen & Co. Ltd., 1963, 125 S., 11 Abb., Leinen, 10 s 6 d. Reviewed by H. Wolffgang.

Horsfall, J. G. (Ed.): Annual review of phytopathology. Vol. 1, Palo Alto, Annual Reviews, Inc., 1963, 469 S., 6 Abb., Leinen, 9,00 $. Reviewed by M. Schmiedeknecht.

Rubin, B. A.; Artsikhovskaya, Ye. V.: Biochemistry and physiology of plant immunity. Oxford, Pergamon Press, 1963, IX und 358 S., 68 Abb., Leinen, £ 5. Reviewed by H. Wolffgang.

Nord, F. F. (Ed.): Advances in Enzymology. Vol. 24, New York und London, Interscience Publishers a division of John Wiley & Sons, 1962, 572 S., 23 Abb., Leinen, 120 s. Reviewed by H. Wolffgang.

Nord, F. F. (Ed.): Advances in Enzymology. Vol. 25, New York und London, Interscience Publishers a division of John Wiley & Sons, 1963, 565 S., 56 Abb., Leinen, 115 s. Reviewed by H. Wolffgang.

Forbes, J.: A laboratory manual for histology. 2. Aufl., New York, Fordham University Press, 1961, 132 S., 3 Abb., brosch., 3,00 $. Reviewed by J. H. Scharf.

Guaoliumi, P.: Las Plagas de la Caña de Azucar en Venezuela. Bd. 1 und 2, Maracay/Yenezuela, Ministerio de Agricultura y Cria Centro de Investigaciones Agronoinicas, 1962, 850 S., 212 Abb., 14 ganzs. Farbtafeln, brosch., 8,00 $. Reviewed by G. Fröhlich.

Clifton, C. E. (Ed.): Annual review of microbiology. Vol. 17, Palo Alto, Annual Reviews, Inc., 1963, 628 S., 19 Abb., Leinen, 9,00 $. Reviewed by K. Naumann.

Ramschandran, G. N. (Ed.): Aspects of protein structure. Proceedings of a symposium held in Madras 14–18 January 1963 and organized by the University of Madras. London und New York, Academic Press, 1963, 380 S., 130 Abb., Leinen, 84 s. Reviewed by P. Hermann.     

Macrotubule-dependent protoplast volume regulation in plasmolysed root-tip cells of Triticum turgidum: involvement of phospholipase D

The probable involvement of phospholipase D (PLD)/phosphatidic acid (PA) signalling in the hyperosmotic stress response of Triticum turgidum root cells was investigated by examining the effects of butanol-1, butanol-2, phosphatidylbutanol (PtdBut), N-acylethanolamine (NAE) and PA on the hyperosmotic response, the organization of the tubulin cytoskeleton and the accumulation of a phosphorylated p38-like mitogen-activated protein (MAP) kinase (phospho-p46) in plasmolysed root cells. The effects of all the treatments were assessed by differential interference contrast (DIC) microscopy of living cells, tubulin immunofluorescence, conventional transmission electron microscopy (TEM), tubulin immunogold localization, protoplast volume measurements and western blot analysis. Butanol-1 and NAE compromised the viability of plasmolysed cells, induced a marked reduction in the plasmolysed protoplast volume, and inhibited hyperosmotically induced tubulin macrotubule formation and the accumulation of phospho-p46. Exogenous PA reinforced the hyperosmotic response of T. turgidum root cells and positively affected tubulin macrotubule formation. Additionally, PA reduced the effects of butanol-1 in plasmolysed cells. Taken together, the data suggest that PLD-mediated PA synthesis occurs upstream of the accumulation of phospho-p46 to regulate hyperosmotically induced macrotubule formation in plasmolysed T. turgidum root cells.     

Functional characterization of naturally occurring genetic variations of the human guanine-rich RNA sequence binding factor 1 (GRSF1)

The guanine-rich RNA sequence binding factor 1 (GRSF1) constitutes an ubiquitously occurring RNA-binding protein (RBP), which belongs to the family of heterogeneous nuclear ribonucleoprotein F/H (hnRNP F/H). It has been implicated in nuclear, cytosolic and mitochondrial RNA metabolism. Although the crystal structures of GRSF1 orthologs have not been solved, amino acid alignments with similar RNA-binding proteins suggested the existence of three RNA-binding domains designated quasi-RNA recognition motifs (qRRMs). Here we established 3D–models for the three qRRMs of human GRSF1 on the basis of the NMR structure of hnRNP F and identified the putative RNA interacting amino acids. Next, we explored the genetic variability of the three qRRMs of human GRSF1 by searching genomic databases and tested the functional consequences of naturally occurring mutants. For this purpose the RNA-binding capacity of wild-type and mutant recombinant GRSF1 protein species was assessed by quantitative RNA electrophoretic mobility shift assays. We found that some of the naturally occurring GRSF1 mutants exhibited a strongly reduced RNA-binding activity although the general protein structure was hardly affected. These data suggested that homozygous allele carriers of these particular mutants express dysfunctional GRSF1 and thus may show defective GRSF1 signaling.     

Detection of mitochondrial defects by laser fluorimetry

The mitochondrial function in skeletal muscle biopsies of three patients with chronic progressive external ophthalmoplegia, having deletions of the mitochondrial DNA, was studied by laser-excited fluorescence measurements of NAD(P)H and flavoproteins in saponin-skinned fibers. We detected substantially elevated steady state redox states of the mitochondrial NAD-system in the muscle fibers of these patients. Moreover, the respiratory chain-linked autofluorescence changes in the muscle fibers of these patients were larger in comparison to controls indicating substantial alterations of the mitochondrial content. These results are in line with the presence of elevated numbers of partially respiratory chain inhibited mitochondria in the skeletal muscle of chronic progressive external ophthalmoplegia patients. (Mol Cell Biochem 174: 97–100, 1997)     

Venom peptide analysis of Vipera ammodytes meridionalis (Viperinae) and Bothrops jararacussu (Crotalinae) demonstrates subfamily-specificity of the peptidome in the family Viperidae

Snake venom peptidomes are valuable sources of pharmacologically active compounds. We analyzed the peptidic fractions (peptides with molecular masses < 10,000 Da) of venoms of Vipera ammodytes meridionalis (Viperinae), the most toxic snake in Europe, and Bothrops jararacussu (Crotalinae), an extremely poisonous snake of South America. Liquid chromatography/mass spectrometry (LC/MS), direct infusion electrospray mass spectrometry (ESI-MS) and matrix-assisted desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) were applied to characterize the peptides of both snake venoms. 32 bradykinin-potentiating peptides (BPPs) were identified in the Crotalinae venom and their sequences determined. 3 metalloproteinase inhibitors, 10 BPPs and a Kunitz-type inhibitor were observed in the Viperinae venom peptidome. Variability in the C-terminus of homologous BPPs was observed, which can influence the pharmacological effects. The data obtained so far show a subfamily specificity of the venom peptidome in the Viperidae family: BPPs are the major peptide component of the Crotalinae venom peptidome lacking Kunitz-type inhibitors (with one exception) while the Viperinae venom, in addition to BPPs, can contain peptides of the bovine pancreatic trypsin inhibitor family. We found indications for a post-translational phosphorylation of serine residues in Bothrops jararacussu venom BPP (S[combining low line]QGLPPGPPIP), which could be a regulatory mechanism in their interactions with ACE, and might influence the hypotensive effect. Homology between venom BPPs from Viperidae snakes and venom natriuretic peptide precursors from Elapidae snakes suggests a structural similarity between the respective peptides from the peptidomes of both snake families. The results demonstrate that the venoms of both snakes are rich sources of peptides influencing important physiological systems such as blood pressure regulation and hemostasis. The data can be used for pharmacological and medical applications.     

Comparative analysis of the human and chicken prion protein copper binding regions at pH 6.5

Recent experimental evidence supports the hypothesis that prion proteins (PrPs) are involved in the Cu(II) metabolism. Moreover, the copper binding region has been implicated in transmissible spongiform encephalopathies, which are caused by the infectious isoform of prion proteins (PrP(Sc)). In contrast to mammalian PrP, avian prion proteins have a considerably different N-terminal copper binding region and, most interestingly, are not able to undergo the conversion process into an infectious isoform. Therefore, we applied x-ray absorption spectroscopy to analyze in detail the Cu(II) geometry of selected synthetic human PrP Cu(II) octapeptide complexes in comparison with the corresponding chicken PrP hexapeptide complexes at pH 6.5, which mimics the conditions in the endocytic compartments of neuronal cells. Our results revealed that structure and coordination of the human PrP copper binding sites are highly conserved in the pH 6.5-7.4 range, indicating that the reported pH dependence of copper binding to PrP becomes significant at lower pH values. Furthermore, the different chicken PrP hexarepeat motifs display homologous Cu(II) coordination at sub-stoichiometric copper concentrations. Regarding the fully cation-saturated prion proteins, however, a reduced copper coordination capability is supposed for the chicken prion protein based on the observation that chicken PrP is not able to form an intra-repeat Cu(II) binding site. These results provide new insights into the prion protein structure-function relationship and the conversion process of PrP.     

Aging of the microenvironment influences clonality in hematopoiesis

The mechanisms of the age-associated exponential increase in the incidence of leukemia are not known in detail. Leukemia as well as aging are initiated and regulated in multi-factorial fashion by cell-intrinsic and extrinsic factors. The role of aging of the microenvironment for leukemia initiation/progression has not been investigated in great detail so far. Clonality in hematopoiesis is tightly linked to the initiation of leukemia. Based on a retroviral-insertion mutagenesis approach to generate primitive hematopoietic cells with an intrinsic potential for clonal expansion, we determined clonality of transduced hematopoietic progenitor cells (HPCs) exposed to a young or aged microenvironment in vivo. While HPCs displayed primarily oligo-clonality within a young microenvironment, aged animals transplanted with identical pool of cells displayed reduced clonality within transduced HPCs. Our data show that an aged niche exerts a distinct selection pressure on dominant HPC-clones thus facilitating the transition to mono-clonality, which might be one underlying cause for the increased age-associated incidence of leukemia.