In Gibberella fujikuroi, ammonium (NH4+) interfered with the production of gibberellic acid (GA3). Optimal production occurred at 19 mm (NH4)2SO4 and the synthesis of GA3 was reduced threefold in a medium with 38 mm (NH4)2SO4. Using a resting cell system with mycelia previously grown on two concentrations (19 mm and 38 mm) of (NH4)2SO4, it was found that NH4+ depressed synthesis of the gibberellin-synthesizing enzymes. Furthermore, addition of NH4+ to a producing system shut off gibberellin formation, indicating that the negative effect of NH4+ ions is also due to inhibition of one or more enzymes in the gibberellin biosynthesis pathway. The onset of gibberellin biosynthesis in media with high (38 mm) and low (19 mm) concentrations of (NH4)2SO4 was studied by addition of cycloheximide to batch cultures of various ages.

Gibberellins are a classic example of the production of plant growth regulators by microorganisms. They are important biotechnological products and are increasingly used in agriculture and horticulture.This article intends to assemble information on the history of the identification of gibberellins (GA) and producing microorganisms, especially Gibberella fujikuroi (Saw.) Wr. Furthermore, the biosynthesis of gibberelins through the isoprenoid biosynthetic pathway will be described. The main product of GA biosynthesis in Gibberella fujikuroi is gibberellic acid (GA3), which is formed from GA4 via GA7. Both the amount and the type of gibberellins produced by the fungus are dependent on the genetic constitution of the strain and the fermentation conditions.Mutation and selection for increased product formation are probably the most important factors in improving the yield of gibberellins. Some publications concerning methods of parasexual recombination will also be summarized. Beside strain improvement of wild strains, medium development and appropriate cultivation techniques (batch, fed-batch-, continuous-, and solid state-fermentation) are very important prerequisites for successful economy of gibberellin production. Furthermore, the most important ways of gibberellin recovery and purification are described. Continuing reductions in the costs make gibberellins more attractive for existing applications and open possibilities for further applications of GA3 and some other active gibberellins like GA4, Ga7, and GA9.

A new method of optimization of the medium composition by biostatistical methods is reported. The well‐known Box‐Wilson scheme combined with the method of optimum curves was applied for an exploration of the response surface. The primary goal has been to optimize the concentration of nutrients for the production of gibberellic acid by the fungus Gibberella fujikuroi with a minimum number of experiments. As the result, a nearly fivefold improvement yield of the was achieved performing only two experiments.

The efficacy of a number of mutagens was examined for Gibberella fujikuroi. Nitrosoguanidine (MNNG) was the most effective mutagen inducing mainly morphological and pigment mutants. X-ray produced small mutagenic effect. After UV-irradiation pigment mutants developed for the most part and a combination of UV-and X-ray-irradiation mainly influenced the growth rate. A combination of UV-irradiation with MNNG elicited the highest number of mutants with increased GA3 production.

Fusarium moniliforme Sheldon (perfect stage Gibberella fujikuroi (SAW. Wollenweber), an ubiquitous fungus belonging to the section Liseola (Booth), is one of the widespread, phytopathogenic fungi. This field fungus common on many crops, including rice, oats, wheat, maize, barley and soybeans was well known because of the ability to produce gibberellins in high quantities. Today beside of the very important gibberellic acid (GA3) other gibberellins such as GA4 and GA7 are of significance for agriculture and horticulture. Moreover, this fungus produces further biologically active metabolites, e.g. pigments, mycotoxins, phytotoxins, oestrogens and extracellular enzymes. Fusarium moniliforme strains are able to produce 2 pigment groups - the karotenoids and the bikaverins, the last of which has antibiotical activity against Leishmania brasiliensis. The biosynthesis of some mycotoxic substances, such as moniliformin, fusaric acid, fusarin C and fusariocin C, is described. From enzymes the milk-clotting rennin, cellulolytic and amylolytic enzymes, pectinases and phenol-degrading enzymes are of economical interest. Therefore, Fusarium moniliforme is a source of different bioactive metabolites. The production is dependent on the conditions and strain specifity.

AbstractThe present review deals with some essential aspects regarding to the microbial gibberellin biosynthesis during the last 10 to 15 years.After a brief historical outline some gibberellins resp. gibberellin‐like substances producing microorganisms (e. g. fungi, bacteria) are presented of which the ability to produce these compounds recently was published. In addition techniques to obtain mutants from the fungus Gibberella fujikuroi by means of physical and chemical methods are described. A further topic of the survey is dedicated to the biosynthetic pathway of gibberellins in the fungus Gibberella fujikuroi as well as the regulation of this biosynthetic route. In this connection especially the dependence of the biosynthesis on environmental factors (e. g. role of various carbon and nitrogen sources in the medium and their relation to each other) are demonstrated.Also a possible role of the gibberellins for the producing fungus itself is discussed.Finally, new fields of application for gibberellic acid and the gibberellins GA4 and GA7 (e. g. animal production, pharmaceutical industry) are presented.

A bacterium capable to lyse viable yeast cells was isolated from compost enriched with baker's yeast cells and was identified as Arthrobacter globiformis. The yeast lytic enzyme complex produced by shaking culture was precipitated with ammonium sulfate, dialyzed and lyophilized. The crude residue contained beta-glucanase and alpha-mannanase, yet not chitinase. Optimale carbon sources in the culture medium for a high enzyme synthesis were 0.5% beta-glucan for the production of beta-glucanase, resp., 3% alpha-mannan for the production of alpha-mannanase. Addition of 10% whole died baker's yeast cells to the culture medium effected similar results. The crude enzyme residue released among other things spheroplasts from cells of the yeast Pichia membranaefaciens, Metschnikowia pulcherrima, Hansenula anomala and Candida guilliermondii "H". However, it did not or only weakly lyse viable cells of the yeasts Rhodotorula rubra, Rhodosporidium toruloides and Sporobolomyces roseus. The mutants of Candida guilliermondii "H" with modified glucan, resp., mannan concentrations in the cell walls did not indicate differences in their susceptibility to lysis.

The Antiproton Accumulator (AA) is a technically advanced, complicated and unusual facility. Its controls had to be built in a short time by a very small permanent staff calling on part-time resources from other parts of CERN. As the AA will eventually be integrated into the PS accelerator complex, its process interface, process computer, systems software and lower level applications software have been made to the new PS standards. For the efficiency of commissioning and first operation the present versions of high level application programs have been written in NODAL by the equipments specialists using a programming philosophy and a new "Touch Terminal" from the SPS. In addition, two desk top computers with a separate GPIB are used for the stochastic cooling system. The paper outlines the pragmatic approach in composing the controls for a complicated machine using the procedures and components available at CERN. The experience gained after an early and successful start-up is reported.

Average pressure and vacuum-stability limit as expected in the presence of a proton beam were measured after in situ treatments such as bakeout under various conditions, argon glow-discharge cleaning and sputter deposition of titanium. Measurements were carried out for test pipes made of stainless steel (untreated, electropolished, or cooled to 77 K), pure titanium and aluminum alloy. The measurement method used to obtain the vacuum-stability limit in the laboratory and in a prototype system is described. The results can be applied also to other systems of different geometry by use of scaling laws. In situ conditioning generally has a stronger influence on vacuum performance than a particular choice of material. Bakeout gives low average pressures and rather good vacuum stability. Glow discharges also increase the vacuum stability but have only a small effect on the static pressure. Coating the beam-pipe wall with titanium by in situ sputtering provides large linear pumping, thus a lower pressure and an extremely good vacuum stability.

A study has been made of the feasibility of building Large Storage Rings (LSR) at CERN using superconducting dipoles and quadrupoles with the 400 GeV proton synchrotron, SPS, serving as injector. Proton-proton collisions at centre-of-mass energies of up to 800 GeV can be obtained in six interaction regions. Two of these provide luminosities exceeding 1033 cm−2 s−1 and would be dedicated to large-transverse-momentum physics. The other four p-p intersections offer much experimental flexibility at somewhat lower luminosity. Provision is made to add an electron storage ring of 20–25 GeV to obtain e-p collisions at up to 200 GeV centre-of-mass energy with a luminosity of 1032 cm−2 s−1 in each of two special e-p interaction regions. Antiproton-proton collisions could be obtained by a minor rearrangement of some elements in two of the interaction regions.

The pressure and stability limit was measured in long and thin pipes after bakeout, glow discharge cleaning and sputter-coating with Ti in situ. In situ-treatments provide a better vacuum performance than any particular choice of pipe material. An average pressure approximately 10/sup -11/ Torr and a critical current > 100 A can be achieved in small aperture proton storage rings with these treatments.

A design is presented for 400 GeV proton-proton storage rings to be added to the CERN SPS. An electron (20-25 GeV) ring is also foreseen and possibilities for antiproton-proton collisions. Eight interaction regions are planned (six for p-p and two for e-p) with high luminosity and good flexibility for physics experiments.

Design and performance of a new hot-filament ionization gauge, specially developed for total pressure measurements down to 10−14 Torr, are described. The gauge features an electrostatically deflected ion beam which is directed at the funnel cathode of a small channel electron multiplier (CEM). The spurious signal due to electronic desorption of ions from the anode is extremely small, because these ions are typically of higher initial total energy than those from the residual gas, and may, therefore, be evicted from the high-energy side of the ion beam that is energetically dispersed by the deflecting electric field. The x-ray background corresponds to a pressure in the 10−14 Torr range, and since it can be measured just by inverting the deflector potential, it may easily be zeroed out electronically. Almost none of the secondary particles, released by x rays or ions from the deflecting electrodes, is counted, because the CEM cathode is operated at high negative potential and because most positive secondary ions are collected at the negative deflecting electrode, due to their small kinetic energy. The gauge’s sensitivity for nitrogen is about 1017 counts/s⋅Torr⋅A, corresponding to 105/Torr for a CEM gain of 107. It is mounted on a 113.5-mm metal flange with ceramic feedthroughs and may be baked up to about 300 °C.