Alam Reza Guo, Q. Guo, Q, and Alam, M. Alhassid, The shell model Monte Carlo approach to level densities:
Penicillium chrysogenum is the industrial producer of the beta-lactam antibiotic penicillin, whose biosynthetic regulation is barely understood. Here we provide a functional analysis of major homologues of the velvet complex in P. Data from northern hybridizations, HPLC quantifications of penicillin titres as well as detailed microscopic investigations clearly show that all regulators play not only a major role in penicillin biosynthesis but are also involved in different and distinct developmental processes.
Furthermore, detailed bimolecular fluorescence complementation assays together with yeast two-hybrid screens led not only to the identification for a velvet-like complex in P. Our results extend the current picture of regulatory networks controlling both fungal secondary metabolism and morphogenesis which is significant for the genetic manipulation of fungal metabolism as part of industrial strain improvement programs.
Mach Gene Technology Group, Inst. For industrial applications this renewable resource is mainly extracted from crustacean shells. However, thitherto only a minute amount of this renewable resource is used in industrial and agricultural applications.
N-acetyl neuraminic acid NeuNAca C9 mono-saccharide, is the most prevalent exponent of sialic acids. Currently, more than 50 derivatives of sialic acids are known to exist in nature.
NeuNAc is believed to serve as a precursor of all these derivatives as all biochemical pathways precede via this substance. In biological systems sialic acids are mostly terminal components of glycoproteins presented at the respective cell surface. Because of its exposed position in cellular systems they play an important role in infection cycles of viral diseases, e.
Therefore, sialic acid derivatives are successfully applied in the therapy of such virus-born diseases. Preparations on the market are e. We will present an alternative strategy of NeuNAc production based on a genetically engineered Trichoderma strain producing and excreting NeuNAc.
For the first time, this poses the introduction of a multi-step enzyme cascade into a filamentous fungus as heterologous host. This strategy involves the application of Trichoderma as a whole-cell catalyst for direct synthesis of NeuNAc from the cheap, renewable biopolymer chitin.
BoxGL Nijmegen, the Netherlands christien. For these purposes Aspergillus functions as a suitable production host. Over the years all kinds of commercially available expression systems have been developed.
A well established expression system is the one based on the protein Glucoamylase GlaA. However, in the case of heterologous protein production the efficiency of these systems is still very depending on the protein to be produced.
Recently, we identified the inuE gene, encoding for the exo-inulinase protein in A. Characteristics of the system were studied by placing gfp behind the inuE promoter.
This reporter strain showed that the inuE gene is highly expressed when grown on inulin and sucrose.
No expression was observed when grown on glucose, fructose and xylose indicating a tight control on different carbon sources. This tight control can be a benefit if the heterologous protein to be produced can be a disadvantage for fungal growth.
Finally, different peroxidases and a laccase were successfully produced in Aspergillus using this novel inducible expression system.
Mach-Aigner Vienna of Technology msteiger mail. Derivatives of NeuNAc are used as neuraminidase inhibitors to treat viral infections like influenza. Therefore, the pharmaceutical industry is interested in a cheap source for NeuNac, but its synthesis is costly current market price: Currently, NeuNac can be produced either by E.
In both cases the substrate used is N-acetylglucosamine, which itself is costly.
Instead of N-acetylglucosamine, we use the renewable source chitin as a substrate. We developed a whole-cell-bio-catalysis process based on the fungus Trichoderma. Trichoderma is known for its high secretory capacity for hydrolytic enzymes.
This filamentous fungus is able to utilize polysaccharides like cellulose or chitin which commonly occur in nature. We use this ability of the fungus to degrade chitin into its monomer N-acetylglucosamine. From N-acetylglucosamine we designed an intracellular enzyme-catalyzed pathway for the synthesis of NeuNac.
Therefore, we heterologously expressed two bacterial enzymes, N-acetylglucosamineepimerase and NeuNAc synthase, in Trichoderma. This is necessary because the wild-type of Trichoderma itself is not able to produce NeuNac. We will illustrate the properties of a recombinant Trichoderma strain, which expresses the two bacterial enzymes, and we will show the ability of this strain to form NeuNac.
This work demonstrates the potential of using Trichoderma as a whole-cell catalytic system.Color was developed in reaction mixtures after the addition of the following reagents: superoxide dismutase (SOD), and guaiacol peroxidase (POD) activities were analysed using the methods described in our previous reports APX‐mediated detoxification of H 2 O 2 is coupled with AsA oxidation.
The reaction mixture was prepared in 50 mM K 3 PO 4 buffer (pH = 7) with 9 mM guaiacol, 10 mM H 2 O 2 and 33 μl of enzyme extract. The enzymatic activity of GPX is expressed as the amount of enzyme required to produce 1 μmol guaiacol dehydrogenation product min -1 mg protein The reaction was cooled to 70° C., KOH ( mg, mmol) was added, then the reaction vas heated at ° C.
for 1 h. The mixture was cooled to room temperature, poured into . The results suggest that the reaction is initialized by the enzymatic 3-methylbenzothiazolinone hydrazone activation, which undergoes electrophilic substitution with m -methoxyphenol in solution, enzymatic activated guaiacol, and chelated p -methoxyphenol at the catalytic site of the laccase.
These reports inspires us to assume that in our reaction, the Co-cluster is a layered double-hydroxide material, the internal structure consists of layered Co(O)OH, which can be transferred to Co(IV) by stepwise proton-coupled electron transfer (PCET).
The rate of reaction varies depending on the metal and the concentration of the acid; the gases produced during the reaction include the nitrogen oxides, nitrogen and ammonia, which may have a toxic or asphyxiating effect.