title: Domain-level identification and quantification of relative prokaryotic cell abundance in microbial communities by Micro-FTIR spectroscopy.
abstract: Domain-level identification of microbial cells or cell-like structures is crucial for investigating natural microbial communities and their ecological significance. By using micro-Fourier transform infrared (micro-FTIR) spectroscopy, we established a technical basis for the domain-level diagnosis and quantification of prokaryotic cell abundance in natural microbial communities. Various prokaryotic cultures (12 species of bacteria and 10 of archaea) were examined using micro-FTIR spectroscopic analysis. The aliphatic CH3 /CH2 absorbance ratios (R3/2 ) showed domain-specific signatures, possibly reflecting distinctive cellular lipid compositions. The signatures were preserved even after chemical cell fixation (formaldehyde) and nucleic acid staining (DAPI) processes - techniques that are essential in studying microbial ecology. The micro-FTIR technique was successfully applied for quantification of the bacteria/archaea abundance ratio in an active microbial mat community in a subsurface hot aquifer stream. We conclude that the micro-FTIR R3/2 measurement is both fast and effective for domain-level diagnosis and quantification of first-order prokaryotic community structures.
authors.affiliation: Department of Earth Science and Astronomy, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
authors.forename: Motoko
authors.initials: M
authors.lastname: Igisu
authors.forename: Ken
authors.initials: K
authors.lastname: Takai
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Ueno
authors.forename: Manabu
authors.initials: M
authors.lastname: Nishizawa
authors.forename: Takuro
authors.initials: T
authors.lastname: Nunoura
authors.forename: Miho
authors.initials: M
authors.lastname: Hirai
authors.forename: Masanori
authors.initials: M
authors.lastname: Kaneko
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Naraoka
authors.forename: Mie
authors.initials: M
authors.lastname: Shimojima
authors.forename: Koichi
authors.initials: K
authors.lastname: Hori
authors.forename: Satoru
authors.initials: S
authors.lastname: Nakashima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohta
authors.forename: Shigenori
authors.initials: S
authors.lastname: Maruyama
authors.forename: Yukio
authors.initials: Y
authors.lastname: Isozaki