Print Email Facebook Twitter Switching from a Unicellular to Multicellular Organization in an Aspergillus niger Hypha Title Switching from a Unicellular to Multicellular Organization in an Aspergillus niger Hypha Author Bleichrodt, R.J. Hulsman, M. Wösten, H.A.B. Reinders, A.J.T. Faculty Applied Sciences Department Biotechnology Date 2015-03-03 Abstract Pores in fungal septa enable cytoplasmic streaming between hyphae and their compartments. Consequently, the mycelium can be considered unicellular. However, we show here that Woronin bodies close ~50% of the three most apical septa of growing hyphae of Aspergillus niger. The incidence of closure of the 9th and 10th septa was even ?94%. Intercompartmental streaming of photoactivatable green fluorescent protein (PA-GFP) was not observed when the septa were closed, but open septa acted as a barrier, reducing the mobility rate of PA-GFP ~500 times. This mobility rate decreased with increasing septal age and under stress conditions, likely reflecting a regulatory mechanism affecting septal pore diameter. Modeling revealed that such regulation offers effective control of compound concentration between compartments. Modeling also showed that the incidence of septal closure in A. niger had an even stronger impact on cytoplasmic continuity. Cytoplasm of hyphal compartments was shown not to be in physical contact when separated by more than 4 septa. Together, data show that apical compartments of growing hyphae behave unicellularly, while older compartments have a multicellular organization. To reference this document use: http://resolver.tudelft.nl/uuid:cb7e36e6-ae66-49bb-8b9e-0848b5e712c3 DOI https://doi.org/10.1128/mBio.00111-15 Publisher American Society for Microbiology ISSN 2150-7511 Source mBio vol. 6 no. 2 e00111-15 Part of collection Institutional Repository Document type journal article Rights © 2015 American Society for Microbiology Files PDF Switching_from_a_Unicellu ... _an....pdf 4.08 MB Close viewer /islandora/object/uuid:cb7e36e6-ae66-49bb-8b9e-0848b5e712c3/datastream/OBJ/view