Jan Singer
Singer Instruments, Roadwater, Somerset, UK, TA23 0RE
Summary
Single-cell screening often involves using a microscope to view the morphology or growth patterns of individual cells when certain nutrients are removed or chemicals/drugs are introduced. It is an essential tool to determine how microorganisms function.
Historically, this form of microscopy has been fraught with difficulties. Primarily, tracking the position of interesting colonies and returning to those same positions proved to be challenging and time-consuming.
Principles
A plate of interest is placed on the microscope plate holder Scan the plate in both X and Y axes to find colonies of interest Mark the places that contain colonies of interest Incubate the plate for some time, revisit plates and return to the colonies of interest to assess changes in morphology or growth patterns.
Theory
Changes in cell morphology could provide great insights into biological processes. For example, budding yeast S. cerevisiae buds once and only once per cell cycle. Observing multiple buds on a single cell would imply that there is a defect in cytokinesis. Single-cell screening allows the researchers to observe these subtle changes in cell morphology, which would otherwise be impossible to observe on a population level.
Screening Process
To begin the inoculum is streaked onto agar. This is then inverted onto a specialized dissection microscope workstation that is designed for morphological screening. These microscopes have motorized stages that allow you to roam across the plate and mark interesting colonies by a simple touch of a button. The microscope automatically remembers the placement of the marked colonies and so the positions can be revisited at the touch of a button. An integrated camera takes images of each colony at various time points and can produce time-lapse recordings.
MSM 400 is undeniably the most powerful tetrad dissection workstation in the World. The built-in software contains useful protocols that automate many of the repetitive aspects of dissection, ageing, and screening studies.