Wednesday, December 12, 2012

Chapter Outline: Gold-tagged in situ hybridization for whole cell detection in environmental samples


Chapter Outline: Gold-tagged in situ hybridization for whole cell detection in environmental samples


Proposed title: Gold-tagged in situ hybridization for whole cell detection in environmental samples                                                                      

Chapter no.: _________

Authors:         Hannes Schmidt (MS) and Thilo Eickhorst (PhD)
                        University of Bremen
                        Leobener Str., UFT
                        28359 Bremen, Germany
                        Phone:             +49(421) 218-63446
Fax:                 +49(421) 218-9863446
                        E-mail: eickh@uni-bremen.de


Notes:
·      TBD


Proposed chapters

In situ detection of microbes in environmental microbiology
Aim
Methods available and their limitations
-       Detection of single microbial cells
-       Identification and visualization in situ
-       Quantification of absolute and relative abundances
-       Top-to-bottom approach

Need for combinative approaches and higher resolution
-       Correlative in situ detection of microbes and living conditions
-       Surface structure and substrate conditions
-       Combination with high resolution microscopy techniques
-       Quantification and localization on different microscopic scales


NanoGold as a marker for in situ detection of microbes
State of the art
-       Nanogold-labeled substrates
-       Immunological approaches
-       ISH-approaches (Table)
-       Autometallography (Silver/Gold)

Problems/drawbacks
-       Review of previously documented problems for ISH techniques
-       General problems in environmental samples
-       Need for increased specificity and signal intensity


Gold-FISH – microscopy/detection of fluorescent and gold signals
Development of the new Gold-FISH protocol
-       Goal: simultaneous application/deposition of fluorescent and gold markers
-       Signal amplification for both markers
-       Enhancement of nanogold particles for EM applications

Results/Applications so far
-       pure and mixed bacterial cultures
-       soil and sediment
-       plant roots

Technical aspects/hints /troubleshooting for the application of Gold-FISH to environmental samples
-       Cell wall permeabilization
-       Autometallography
-       Surface charge
-       Computer-aided analysis


Potential for gold-based detection techniques in Environmental microbiology

-       Correlative microcopy of Gold-FISH (e.g. FM and SEM-EDS)
-       Combination with nanoSIMS
-       Potential for non-invasive microscopy (e.g. X-ray CT)


Chapter Highlights
The following concepts will be conveyed in this chapter:
  1. Novel approach for a simultaneous labeling of microorganisms with a fluorescent dye and nanogold
  2. Optimization of specific nanogold deposition by tyramide signal amplification
  3. Possible application of different microscopy techniques for the analysis of gold-FISH labeled single cells
  4. Microorganism interactions on different surface morphologies and microenvironments in terms of structure and biogeochemical conditions
  5. Element-microorganism interactions



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