| 1. |
- Bush, Matthew J, et al.
(författare)
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c-di-GMP signalling and the regulation of developmental transitions in streptomycetes.
- 2015
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Ingår i: Nature Reviews. Microbiology. - : Springer Science and Business Media LLC. - 1740-1534 .- 1740-1526. ; 13:12, s. 749-760
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Forskningsöversikt (refereegranskat)abstract
- The complex life cycle of streptomycetes involves two distinct filamentous cell forms: the growing (or vegetative) hyphae and the reproductive (or aerial) hyphae, which differentiate into long chains of spores. Until recently, little was known about the signalling pathways that regulate the developmental transitions leading to sporulation. In this Review, we discuss important new insights into these pathways that have led to the emergence of a coherent regulatory network, focusing on the erection of aerial hyphae and the synchronous cell division event that produces dozens of unigenomic spores. In particular, we highlight the role of cyclic di-GMP (c-di-GMP) in controlling the initiation of development, and the role of the master regulator BldD in mediating c-di-GMP signalling.
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| 2. |
- Schlimpert, Susan, et al.
(författare)
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Fluorescence Time-lapse Imaging of the Complete S. venezuelae Life Cycle Using a Microfluidic Device.
- 2016
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Ingår i: Journal of Visualized Experiments. - : MyJove Corporation. - 1940-087X. ; :108
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Tidskriftsartikel (refereegranskat)abstract
- Live-cell imaging of biological processes at the single cell level has been instrumental to our current understanding of the subcellular organization of bacterial cells. However, the application of time-lapse microscopy to study the cell biological processes underpinning development in the sporulating filamentous bacteria Streptomyces has been hampered by technical difficulties. Here we present a protocol to overcome these limitations by growing the new model species, Streptomyces venezuelae, in a commercially available microfluidic device which is connected to an inverted fluorescence widefield microscope. Unlike the classical model species, Streptomyces coelicolor, S. venezuelae sporulates in liquid, allowing the application of microfluidic growth chambers to cultivate and microscopically monitor the cellular development and differentiation of S. venezuelae over long time periods. In addition to monitoring morphological changes, the spatio-temporal distribution of fluorescently labeled target proteins can also be visualized by time-lapse microscopy. Moreover, the microfluidic platform offers the experimental flexibility to exchange the culture medium, which is used in the detailed protocol to stimulate sporulation of S. venezuelae in the microfluidic chamber. Images of the entire S. venezuelae life cycle are acquired at specific intervals and processed in the open-source software Fiji to produce movies of the recorded time-series.
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| 3. |
- Schlimpert, Susan, et al.
(författare)
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Two dynamin-like proteins stabilize FtsZ rings during Streptomyces sporulation
- 2017
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 114:30, s. 6176-6183
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Tidskriftsartikel (refereegranskat)abstract
- During sporulation, the filamentous bacteria Streptomyces undergo a massive cell division event in which the synthesis of ladders of sporulation septa convert multigenomic hyphae into chains of unigenomic spores. This process requires cytokinetic Z-rings formed by the bacterial tubulin homolog FtsZ, and the stabilization of the newly formed Z-rings is crucial for completion of septum synthesis. Here we show that two dynamin-like proteins, DynA and DynB, play critical roles in this process. Dynamins are a family of large, multidomain GTPases involved in key cellular processes in eukaryotes, including vesicle trafficking and organelle division. Many bacterial genomes encode dynamin-like proteins, but the biological function of these proteins has remained largely enigmatic. Using a cell biological approach, we show that the two Streptomyces dynamins specifically localize to sporulation septa in an FtsZ-dependent manner. Moreover, dynamin mutants have a cell division defect due to the decreased stability of sporulation-specific Z-rings, as demonstrated by kymographs derived from time-lapse images of FtsZ ladder formation. This defect causes the premature disassembly of individual Z-rings, leading to the frequent abortion of septum synthesis, which in turn results in the production of long spore-like compartments with multiple chromosomes. Two-hybrid analysis revealed that the dynamins are part of the cell division machinery and that they mediate their effects on Z-ring stability during developmentally controlled cell division via a network of protein–protein interactions involving DynA, DynB, FtsZ, SepF, SepF2, and the FtsZ-positioning protein SsgB.
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