Simultaneous Fluorescence In Situ Hybridization of mRNA and rRNA in Environmental Bacteria

AUTOR(ES)

Pernthaler, Annelie

FONTE

American Society for Microbiology

RESUMO

We developed for Bacteria in environmental samples a sensitive and reliable mRNA fluorescence in situ hybridization (FISH) protocol that allows for simultaneous cell identification by rRNA FISH. Samples were carbethoxylated with diethylpyrocarbonate to inactivate intracellular RNases and pretreated with lysozyme and/or proteinase K at different concentrations. Optimizing the permeabilization of each type of sample proved to be a critical step in avoiding false-negative or false-positive results. The quality of probes as well as a stringent hybridization temperature were determined with expression clones. To increase the sensitivity of mRNA FISH, long ribonucleotide probes were labeled at a high density with cis-platinum-linked digoxigenin (DIG). The hybrid was immunocytochemically detected with an anti-DIG antibody labeled with horseradish peroxidase (HRP). Subsequently, the hybridization signal was amplified by catalyzed reporter deposition with fluorochrome-labeled tyramides. p-Iodophenylboronic acid and high concentrations of NaCl substantially enhanced the deposition of tyramides and thus increased the sensitivity of our approach. After inactivation of the antibody-delivered HRP, rRNA FISH was performed by following routine protocols. To show the broad applicability of our approach, mRNA of a key enzyme of aerobic methane oxidation, particulate methane monooxygenase (subunit A), was hybridized with different types of samples: pure cultures, symbionts of a hydrothermal vent bivalve, and even sediment, one of the most difficult sample types with which to perform successful FISH. By simultaneous mRNA FISH and rRNA FISH, single cells are identified and shown to express a particular gene. Our protocol is transferable to many different types of samples with the need for only minor modifications of fixation and permeabilization procedures.

Documentos Relacionados

• Changes in rRNA Levels during Stress Invalidates Results from mRNA Blotting: Fluorescence In Situ rRNA Hybridization Permits Renormalization for Estimation of Cellular mRNA Levels
• Counting and Size Classification of Active Soil Bacteria by Fluorescence In Situ Hybridization with an rRNA Oligonucleotide Probe
• Community Composition of Marine Bacterioplankton Determined by 16S rRNA Gene Clone Libraries and Fluorescence In Situ Hybridization
• Use of rRNA fluorescence in situ hybridization for measuring the activity of single cells in young and established biofilms.
• Nutritional and growth control of ribosomal protein mRNA and rRNA in Neurospora crassa.