title: Imaging internal features of whole, unfixed bacteria.
abstract: Wet scanning-transmission electron microscopy (STEM) is a technique that allows high-resolution transmission imaging of biological samples in a hydrated state, with minimal sample preparation. However, it has barely been used for the study of bacterial cells. In this study, we present an analysis of the advantages and disadvantages of wet STEM compared with standard transmission electron microscopy (TEM). To investigate the potential applications of wet STEM, we studied the growth of polyhydroxyalkanoate and triacylglycerol carbon storage inclusions. These were easily visible inside cells, even in the early stages of accumulation. Although TEM produces higher resolution images, wet STEM is useful when preservation of the sample is important or when studying the relative sizes of different features, since samples do not need to be sectioned. Furthermore, under carefully selected conditions, it may be possible to maintain cell viability, enabling new types of experiments to be carried out. To our knowledge, internal features of bacterial cells have not been imaged previously by this technique.
authors.affiliation: Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Thomson
authors.forename: Kevin
authors.initials: K
authors.lastname: Channon
authors.forename: Noor Azlin
authors.initials: NA
authors.lastname: Mokhtar
authors.forename: Lech
authors.initials: L
authors.lastname: Staniewicz
authors.forename: Ranjana
authors.initials: R
authors.lastname: Rai
authors.forename: Ipsita
authors.initials: I
authors.lastname: Roy
authors.forename: Shun
authors.initials: S
authors.lastname: Sato
authors.forename: Takeharu
authors.initials: T
authors.lastname: Tsuge
authors.forename: Athene M
authors.initials: AM
authors.lastname: Donald
authors.forename: David
authors.initials: D
authors.lastname: Summers
authors.forename: Easan
authors.initials: E
authors.lastname: Sivaniah
mesh_terms: D001419:Bacteria / Q000648:ultrastructure*; D001431:Bacteriological Techniques / Q000379:methods; D002479:Inclusion Bodies / Q000648:ultrastructure*; D008854:Microscopy, Electron / Q000379:methods*