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Structural and functional properties of plasma membranes from the filamentous fungus Penicillium chrysogenum
D J Hillenga1, H J Versantvoort, A J Driessen
1Department of Microbiology, Unviersity of Groningen, The Netherlands.
Abstract:
Functional plasma membranes from the filamentous fungus Penicillium chrysogenum have been isolated with the objective of studying transport processes. The isolation procedure consists of three steps, namely homogenization of cells with a Braun MSK homogenizer, followed by Percoll gradient centrifugation and floatation of membranes in a three-step Nycodenz gradient. This method can be applied to strains which differ significantly in morphology and penicillin-production capacity. Plasma membranes were fused with liposomes containing the beef heart mitochondrial cytochrome-c oxidase. In the presence of reduced cytochrome c, the hybrid membranes maintained a high proton motive force that functions as a driving force for the uptake of the amino acids arginine and valine via distinct transport systems.
Insights
Researchers isolated functional plasma membranes from Penicillium chrysogenum to study transport. The hybrid membranes, incorporating cytochrome-c oxidase, successfully drove amino acid uptake via distinct systems.
Area of Science:
- Biochemistry
- Molecular Biology
- Mycology
Background:
- Understanding nutrient transport in filamentous fungi is crucial for optimizing industrial processes.
- Penicillium chrysogenum is a key fungus in biotechnology, particularly for penicillin production.
Purpose of the Study:
- To isolate functional plasma membranes from Penicillium chrysogenum for transport studies.
- To investigate the role of proton motive force in amino acid uptake.
Main Methods:
- Cell homogenization using a Braun MSK homogenizer.
- Isolation of plasma membranes via Percoll and Nycodenz density gradient centrifugation.
- Fusion of fungal plasma membranes with liposomes containing beef heart mitochondrial cytochrome-c oxidase.
Main Results:
- A robust method for isolating functional plasma membranes applicable to diverse Penicillium strains was developed.
- Hybrid membranes exhibited a high proton motive force when supplied with reduced cytochrome c.
- This proton motive force effectively drove the uptake of arginine and valine through specific transport systems.
Conclusions:
- The developed isolation technique yields functional plasma membranes suitable for biochemical analysis.
- Proton motive force is a key regulator of amino acid transport in Penicillium chrysogenum.
- Distinct transport systems for arginine and valine were identified and characterized.