This is the institutional Repository of the Helmholtz Centre for Infection Research in Braunschweig/Germany (HZI), the Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Saarbrücken/Germany, the TWINCORE Zentrum für Exprerimentelle und Klinische Infektionsforschung, Hannover/Germany,Helmholtz-Institut für RNA-basierte Infektionsforschung (HIRI), Würzburg/Germany, Braunschweig Integrated Centre for Systems biology (BRICS), Centre for Structural Systems Biology (CSSB) the Study Centre Hannover, Hannover/Germany and the Centre for Individualised Infection Medicine (CiiM).



    Reichenbach, Hans; Gesellschaft fuer Biotechnologische Forschung, Abteilung Mikrobiologie D-3300 Braunschweig-Stoeckheim Federal Republic of Germany (1975)
    Chondromyces apiculatus, strain Cm a2, isolated in Minneapolis from decaying wood, was grown as a pure culture on yeast agar for years without ever producing fruiting bodies. When agar blocks with fractions of the swarm edge were punched from the culture plate and transferred to a salt solution containing Ca’ and Mg**, well differentiated fruiting bodies developed. Fruiting body production was found to be under strict control by a number of environmental factors: 1)The temperature must not exceed 30°C, although good arowth occurs still several degrees higher. 2) The surface of the agar block must not be submerged under the surface of the salt solution. 3) The cultures must be illuminated during induction. The quality of the light has no influence, at least in the visible range, even red light being fully effective. In red light the fruiting bodies remain pale,however, because carotenoid synthesis is at dark level under this condition. Light has to be present during the whole developmental process, as cell accumulation as well as fruiting body morphogenesis depend on licht. 4) The relative proportion of the Ca** and Mg** concentrations has a striking effect on the shape of the developing fruiting bodies. 5) Addition of nutrients to the salt solution, e.g. of a little Casitone solution, suppresses fruiting body formation completely; neither are fruiting bodies obtained by induction in deionized water. Finally, 6) if the initial population density is too low, no fruiting bodies can be formed even if all other conditions are right. The induction system worked out for Cm a2, seems to be specific for this one strain: no fruiting bodies were obtained under identical conditions with a number of other strains of Cm. apiculatus, nor with Cm. pediculatus, let alone myxobacteria of other genera.

    Filer, D.; Rosenberg, E.; Kindler, S. H.; Department of Microbiology, Tel Aviv University Tel Aviv, Israel (1975)
    Purified capsular material of Myxococcus xanthus has previously been shown to be composed mainly of N-acetylgalactosamine, glucose and glycine. Investigations carried out during the last two years have demonstrated that UDP Gal NAc and UDP Glc are the major precursors. Biosynthesis of capsule was studied by measuring the incorporation of 140 _upp Gal NAc, 344-UDP Glc and Su-glycine into TCA insoluable material. All three compounds were incorporated more rapidly than into crude extracts prepared from 2 hr glycerol induced myxospores that in similar extracts prepared from vegetative cells. Preliminary studies indicated that incorporation of UDP Gal NAc was stimulated by UDP Glc and to a lesser degree by glycine and ATP. Similarly, incorporation of UDP Glc was stimulated by UDP Gal NAc, glycine and ATP. Both of the transferase activities were found exclusively in the 30,000 x g pellet, which were used for further studies. The glycine incorporating activity remained in the supernatant. Both transferase activities were linear with time for 1 hr and with protein concentration between 0.1 - 1.0 mg/ml. The incorporation of UDP Glc and UDP Gal NAc were absolutely dependent upon divalent cations and were inhibited 40 % by 100 pg/ml Bacitracin. In the absence of ATP, the incorporation of UDP Glc was stimulated by UDP Gal NAc, but UDP Gal NAc incorporation was not stimulated by various concentrations of UDP Gic. In both cases, the label was incorporated into the 30,000 x g pellet, from which it could be recovered as radioactive glucose and galactosamine following acid hydrolysis and paper chromatography.

    Wireman, J.; Dworkin, Martin; Department of Microbiology, University of Minnesota, Minneapolis, Minnesota, USA (1975)
    Massive cell death occurs during fruiting construction by several species of Myxococcus . The events which occur lead us to the hypothesis that regulated senescence and cell death are integral part of myxobacterial development. During fruiting body formation by M. xanthus 60 - 8) % of the vegetative cells lyse. The majority of the survivina cells are eventually converted to myxospores in the fruiting body. This lysis has been measured both by the loss of 3y-methy1 thymidine label from DHA of the cells and by actual cell counts. Such lysis occurs under a variety of conditions leading to fruiting body formation. We have also demonstrated lysis during fruiting body formation in Myxococcus fulvus and Myxococcus virescens. If cells are removed at various times during fruiting body formation and replaced in a liquid growth medium the tendency to lyse is reversible until the fruiting bodies have formed; at that time the vegetative cells become irreversibly committed to lysis. We suggest that lysis in the organisms we have examined is a functional and necessary part of the developmental cycle. It is possible that the lysing cells are providing a source of biosynthetic precursors and/or a source of energy for the formation of myxospores and/or fruitina bodies.

    White, D.; Indiana University, Dept. of Microbiology Bloomington, Indiana/USA (1975)
    An extracellular coat from glycerol-induced myxospore of Myxococcus xanthus has been isolated and characterized. Coats were examined chemically and using both transmission and scanning electron microscopy. On a dry weight basis, approximately 75 % of the coat is polysaccharide composed entirely of galactosamine and glucose. The reminder of the coat is protein (14 %), glycine (8 %) and organic phosphorus (less than 1 %). Coats remained morphologically intact despite boiling in 10 M urea, sodium lauryl sulfate plus B-mercaptoethanol, or extraction with warm phenol. Coats also resisted digestion with a variety of proteolytic and polysaccharide degrading enzymes. Synthesis of myxospore coat begins approximately 1 hour after the addition of glycerol to a culture. One portion of the coat is complete by 5 - 6 hours but additional material consisting primarily of glucose is added after 8 hours.

    Grilione, P. L.; Pangborn, J.; San José State University, San José, California /USA, University of California, Davis, California /USA (1975)
    The study to be presented consists of two related parts. Scanning. electron microscopy was employed 1) to observe mature fruiting bodies of several myxobacter genera and 2) to study details of fruiting body formation by Stigmatella aurantica and Chondromyces crocatus. fiicrographs representative of both parts will be shown. Initially, technics for optimum fruiting body production.and for specimen preparation were perfected on the structually less complex fruiting bodies produced by species of Myxococcus and Cystobacter. These were then modified to permit an in depth study of fruiting body formation by pure cultures of S. aurantica and C. crocatus. In summary, vegetative cells of the latter two species were grown and then transferred to a nonnutrient medium for fructification. Fruiting‘body formation was interrupted at various stages by fixation with glutaraldehyde vapours. Fixed and dehydrated specimen were dried by the critical point method in liquid C0,. Fruiting in both species begins with an aggregation center which closely resembles a fried egg in appearance. It is after this stage that significant and consistant differences occur in fruiting between the two organisms., In S. aurantica, the "yolk region" of the fried egg stage extends upward to form a column-like stalk which is nearly uniform in diameter throughout its length. At maximum height the terminus of the stalk develops into an irregular pattern of bud-like swellings which eventually differentiate into sporangia. C. crocatus differs in chat the "yolk region" enlarges into a large bulbous structure initially. The bulb anpears to be lifted upward by a slender stalk which develops beneath. The bulb differentiates into numerous bud-like swellings at maximum stalk height, but unlike Stigmatella, the swellings and immature sporanoia are arranged in a distinctive radial pattern. This symmetry is lost as more sporangia develop and mature. Stalks of two week old mature fruiting bodies of both species appear cellular in composition. Stereomicrographs of cross sections of broken mature stalks suggest the cells are oriented parallel to the long axis of the stalk.

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