Single beam and holographic optical tweezer micromanipulation have been explored. The single beam system used was a simple, compact, easy-to-use, safe and robust optical tweezer setup mounted on a standard research grade light microscope. It was specifically designed to produce high quality images and to be used with brightfield, phase contrast, differential interference contrast and fluorescence optics. The holographic optical tweezer system used involved the creation of multiple traps and complex patterns of light, and was employed with a range of laser wavelengths. The various optical tweezer systems were used in a wide range of applications to trap and micromanipulate whole fungal cells, organelles within cells, and synthetic beads. The experimental studies demonstrated how optical tweezers can be used to: unambiguously determine whether hyphae are actively homing towards each other; move the Spitzenkörper and change the pattern of hyphal morphogenesis; create ‘pseudowalls’ of light to control hyphal growth over extended distances; make piconewton force measurements; investigate the tethering of organelles within cells; mechanically stimulate hyphal tips; produce stable, fixed arrays of cells; and, deliver chemicals to localized regions of hyphae. A significant finding was that germ tubes seem to generate significantly lower growth forces than leading vegetative hyphae. An assessment of the photodamage caused to spores showed that ungerminated spores could be trapped for short periods of time without damage, but could not germinate whilst being continuously trapped. However once germinated, spores continually trapped for 25 min exhibited no deleterious effects with regard to conidial anastomosis tube growth, homing or fusion.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:664032 |
| Date | January 2007 |
| Creators | Wright, Graham D. |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/11616 |
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