Utilization of somatic cell hybrids for genetic studies in man

Summary Mammalian cells grown in vitro can be substituted for the intact organisms in genetic studies. Parasexual events in these cells lead to the formation of proliferating somatic cell hybrids. The production and isolation of intra- and interspecific somatic cell hybrids and their use in human genetic studies are reviewed.Cell hybrids have been successfully applied to characterize inherited biochemical defects in man and to establish linkage relationships and assignment of human genes. The prerequisites and pitfalls of this approach are discussed. Recent results allow the assignment of genes to 15 human chromosomes. The data resulting from these studies could be useful for prenatal diagnosis or the therapy of inherited diseases.

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Zusammenfassung In vitro kultivierte somatische Zellen von Säugetieren können lebende Tiere bei genetischen Untersuchungen ersetzen. Parasexuelle Vorgänge in diesen Zellen führen zur Bildung proliferierender Hybriden somatischer Zellen.Die vorliegende Übersicht behandelt die Bildung und Isolierung intra- und interspezifischer Hydbriden somatischer Zellen und ihre Verwendung bei der Untersuchung humangenetischer Fragestellungen. Zellhyriden wurden mit Erfolg zur Charakterisierung erblicher biochemischer Defekte beim Menschen und zu Genkopplungs- und Lokalisierungsanalyse menschlicher Gene eingesetzt. Voraussetzungen und Schwierigkeiten der Methode werden besprochen. Gegenwärtig können mit diesem Verfahren 15 menschlichen Chromosomen Gene oder Kopplungsgruppen zugeordnet werden. Die Ergebnisse dieser Untersuchungen können hilfreich bei den Bemühungen sein, genetische Defekte durch pränatale Diagnose frühzeitig zu erkennen oder betroffene Individuen zu behandeln.

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The author's work on cell hybrids is supported by the Deutsche Forschungsgemeinschaft.     

Inhibition of gluconeogenesis from proline by ethanol oxidation

The effect of ethanol oxidation on proline metabolism in the perfused rat liver was studied. Ethanol oxidation inhibited proline consumption by about 80%, glucose production by 92% and urea formation by 60%. The mechanism in the [NADH]/[NAD⁺]-ratio.     

Low-dose intragastric administration of Phaseolus vulgaris agglutinin (PHA) does not induce immunoglobulin E (IgE) production in Sprague-Dawley rats

Native Phaseolus vulgaris agglutinin (PHA) poses a potential health threat, when ingested with improperly cooked red kidney beans. Since PHA triggers human basophilic granulocytes in culture to rapidly release considerable amounts of interleukin-(IL-)4 and IL-13, key cytokines for inducing immunoglobulin E (IgE) production, the question was addressed whether this lectin can evoke in vivo IgE production. IgE-low-responder (Sprague-Dawley) rats received PHA (6 mg/rat/day) intragastrically by gavage over a period of 10 days. Up to day 35, there was no IgE induction regardless of whether the animals were boostered subcutaneously with PHA or not, indicating that PHA cannot be regarded as a general IgE inducer in rats.     

Characterization and regional mapping of new anonymous chromosome 20-specific DNA markers isolated from a flow-sorted DNA library

Employing the flow-sorted chromosome 20-specific DNA library LL20NS01, we isolated seven novel unique poly- and monomorphic DNA markers specific to human chromosome 20. Initially, 201 phage clones were analyzed regarding insert size and repetitivity. By testing 14 single- and low-copy number clones for their ability to detect RFLPs, three polymorphisms were revealed by two probes, pFMS22-1.4 [D20S22] and pFMS76 [D20S23]. Seven of twenty probes (35%) were assigned to chromosome 20 using a somatic cell hybrid DNA panel. Five of them were regionally mapped by in situ hybridization. Three DNA markers, pFMS51 [D20S29], pFMS76 [D20S23], and pFMS106 [D20S30], were assigned to 20p11.2-p12, and two markers, pFMS22-1.4 [D20S22] and pFMS135 [D20S31], to 20q12-q13.3. Our new chromosome 20-specific DNA markers should be useful for the molecular characterization of this rather underpopulated human chromosome.     

Piriformospora indica mycorrhization increases grain yield by accelerating early development of barley plants

Root colonization by the basidiomycete fungus Piriformospora indica induces host plant tolerance against abiotic and biotic stress, and enhances growth and yield. As P. indica has a broad host range, it has been established as a model system to study beneficial plant-microbe interactions. Moreover, its properties led to the assumption that P. indica shows potential for application in crop plant production. Therefore, possible mechanisms of P. indica improving host plant yield were tested in outdoor experiments: Induction of higher grain yield in barley was independent of elevated pathogen levels and independent of different phosphate fertilization levels. In contrast to the arbuscular mycorrhiza fungus Glomus mosseae total phosphate contents of host plant roots and shoots were not significantly affected by P. indica. Analysis of plant development and yield parameters indicated that positive effects of P. indica on grain yield are due to accelerated growth of barley plants early in development.Key words: mycorrhiza, barley development, Piriformospora indica, phosphate uptake, grain yield, pathogen resistanceThe wide majority of plant roots in natural ecosystems is associated with fungi, which very often play an important role for the host plants'' fitness.¹ The widespread arbuscular mycorrhizal (AM) symbiosis formed by fungi of the phylum Glomeromycota is mainly characterized by providing phosphate to their host plant in exchange for carbohydrates.^2,3 Fungi of the order Sebacinales also form beneficial interactions with plant roots and Piriformospora indica is the best-studied example of this group.⁴ This endophyte was originally identified in the rhizosphere of shrubs in the Indian Thar desert,⁵ but it turned out that the fungus colonizes roots of a very broad range of mono- and dicotyledonous plants,⁶ including major crop plants.^7–9 Like other mutualistic endophytes, P. indica colonizes roots in an asymptomatic manner¹⁰ and promotes growth in several tested plant species.^6,11,12 The root endophyte, moreover, enhances yield in barley and tomato and increases in both plants resistance against biotic stresses,^7,9 suggesting that application in agri- and horticulture could be successful.     

Book reviews

Ohne Zusammenfassung

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Book reviews

     

Metabolite profiling of maize grain: differentiation due to genetics and environment

A comparative metabolite profiling approach based on gas chromatography-mass spectrometry (GC/MS) was applied to investigate the impact of genetic background, growing location and season on the chemical composition of maize grain. The metabolite profiling protocol involved sub-fractionation of the metabolites and allowed the assessment of about 300 distinct analytes from different chemical classes (polar to lipophilic), of which 167 could be identified. A comparison, over three consecutive growing seasons, of the metabolite profiles of four maize cultivars which differed in their maturity classification, was carried out using principal component analysis (PCA). This revealed a strong separation of one cultivar in the first growing season, which could be explained by the immaturity of the kernels of this cultivar compared with others in the field trial. Further evaluations by pair-wise comparison using Student’s t-test and analysis of variance (ANOVA) showed that the growing season was the most prominent impact factor driving variation of the metabolite pool. An increased understanding of metabolic variation was achieved by analysis of a second sample set comprising one cultivar grown for 3 years at four locations. The applied GC/MS-based metabolite profiling demonstrated the natural variation in maize grain metabolite pools resulting from the interplay of environment, season, and genotype.