scholarly journals A sample cell for the study of enzyme-induced carbonate precipitation at the grain-scale and its implications for biocementation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jennifer Zehner ◽  
Anja Røyne ◽  
Pawel Sikorski
Keyword(s):  
Real Time ◽  
Laser Scanning Microscopy ◽  
In Situ Monitoring ◽  
Confocal Laser ◽  
Precipitation Process ◽  
Successful Implementation ◽  
Detailed Knowledge ◽  
Carbonate Precipitation ◽  
Sample Cell

AbstractBiocementation is commonly based on microbial-induced carbonate precipitation (MICP) or enzyme-induced carbonate precipitation (EICP), where biomineralization of $$\text {CaCO}_{3}$$ CaCO 3 in a granular medium is used to produce a sustainable, consolidated porous material. The successful implementation of biocementation in large-scale applications requires detailed knowledge about the micro-scale processes of $$\text {CaCO}_{3}$$ CaCO 3 precipitation and grain consolidation. For this purpose, we present a microscopy sample cell that enables real time and in situ observations of the precipitation of $$\text {CaCO}_{3}$$ CaCO 3 in the presence of sand grains and calcite seeds. In this study, the sample cell is used in combination with confocal laser scanning microscopy (CLSM) which allows the monitoring in situ of local pH during the reaction. The sample cell can be disassembled at the end of the experiment, so that the precipitated crystals can be characterized with Raman microspectroscopy and scanning electron microscopy (SEM) without disturbing the sample. The combination of the real time and in situ monitoring of the precipitation process with the possibility to characterize the precipitated crystals without further sample processing, offers a powerful tool for knowledge-based improvements of biocementation.

scholarly journals Corrosion Properties of Biodegradable AZ31 and ZK60 Magnesium Alloys: In Situ Study

2021 ◽  
Vol 6 (1) ◽  
pp. 3
Author(s):  
Evgeniy Merson ◽  
Vitaliy Poluyanov ◽  
Dmitry Merson ◽  
Pavel Myagkikh
Keyword(s):  
Corrosion Rate ◽  
Real Time ◽  
Hydrogen Evolution ◽  
Magnesium Alloys ◽  
Laser Scanning Microscopy ◽  
Ex Situ ◽  
Confocal Laser ◽  
Time Interval ◽  
Surface Observation

Biodegradable magnesium alloys are promising materials for application in medicine. The corrosion rate and type of corrosion are among the most important properties for this kind of materials. The fine-grained biodegradable alloys AZ31 (hot-rolled) and ZK60 (extruded) were studied in the present work with the use of in situ methods including the hydrogen evolution corrosion rate measurement and real-time surface observation as well as ex situ methods such as the weight loss assessment and the post-mortem examination by confocal laser scanning microscopy. The experimental methods included immersion test in SBF (0.9% NaCl aqueous solution) during 120 h with 37 °C with recirculating corrosion media. The hydrogen evolution was measured with a burette with a constant time interval of 1 hour. The real-time surface observation was carried out with a high-resolution camera. The measurement of pH level was done twice a day. Corrosion rate curves, 3D morphology of corroded morphology and video recordings showing evolution of corrosion damage have been obtained. As a result, ZK60 was found to be less corrosion-resistant and addicted to pitting corrosion, whereas AZ31 showed pronounced susceptibility to filiform corrosion.

scholarly journals In Situ Monitoring of the Antibacterial Activity of a Copper–Silver Alloy Using Confocal Laser Scanning Microscopy and pH Microsensors

2019 ◽  
Vol 3 (11) ◽  
pp. 1900044 ◽  
Author(s):  
Nicole Ciacotich ◽  
Kasper Nørskov Kragh ◽  
Mads Lichtenberg ◽  
Jens Edward Tesdorpf ◽  
Thomas Bjarnsholt ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Confocal Laser Scanning Microscopy ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
In Situ Monitoring ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser ◽  
Silver Alloy

scholarly journals Distribution of Phytoplasmas in Infected Plants as Revealed by Real-Time PCR and Bioimaging

2004 ◽  
Vol 17 (11) ◽  
pp. 1175-1184 ◽  
Author(s):  
Nynne Meyn Christensen ◽  
Mogens Nicolaisen ◽  
Michael Hansen ◽  
Alexander Schulz
Keyword(s):  
Real Time ◽  
Laser Scanning ◽  
Infected Plant ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Euphorbia Pulcherrima ◽  
Pcr Assay ◽  
Sieve Tubes ◽  
Polymerase Chain

Phytoplasmas are cell wall-less bacteria inhabiting the phloem and utilizing it for their spread. Infected plants often show changes in growth pattern and a reduced crop yield. A quantitative real-time polymerase chain reaction (Q-PCR) assay and a bioimaging method were developed to quantify and localize phytoplasmas in situ. According to the Q-PCR assay, phytoplasmas accumulated disproportionately in source leaves of Euphorbia pulcherrima and, to a lesser extent, in petioles of source leaves and in stems. However, phytoplasma accumulation was small or nondetectable in sink organs (roots and sink leaves). For bioimaging, infected plant tissue was stained with vital fluorescence dyes and examined using confocal laser scanning microscopy. With a DNA-sensitive dye, the pathogens were detected exclusively in the phloem, where they formed dense masses in sieve tubes of Catharanthus roseus. Sieve tubes were identified by counterstaining with aniline blue for callose and multiphoton excitation. With a potentiometric dye, not all DNA-positive material was stained, suggesting that the dye stained metabolically active phytoplasmas only. Some highly infected sieve tubes contained phytoplasmas that were either inactive or dead upon staining.

scholarly journals Dual Labeling of Pseudomonas putida with Fluorescent Proteins for In Situ Monitoring of Conjugal Transfer of the TOL Plasmid

2003 ◽  
Vol 69 (8) ◽  
pp. 4846-4852 ◽  
Author(s):  
Y. Venkata Nancharaiah ◽  
Pierre Wattiau ◽  
Stefan Wuertz ◽  
Stephan Bathe ◽  
S. Venkata Mohan ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Pseudomonas Putida ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Laser Scanning Microscopy ◽  
In Situ Monitoring ◽  
Confocal Laser ◽  
Tol Plasmid

ABSTRACT We describe here a dual-labeling technique involving the green fluorescent protein (GFP) and the red fluorescent protein (DsRed) for in situ monitoring of horizontal gene transfer via conjugation. A GFPmut3b-tagged derivative of narrow-host-range TOL plasmid (pWWO) was delivered to Pseudomonas putida KT2442, which was chromosomally labeled with dsRed by transposon insertion via biparental mating. Green and red fluorescent proteins were coexpressed in donor P. putida cells. Cells expressing both fluorescent proteins were smaller in size than cells expressing GFP alone. Donors and transconjugants in mixed culture or sludge samples were discriminated on the basis of their fluorescence by using confocal laser scanning microscopy. Conjugal plasmid transfer frequencies on agar surfaces and in sludge microcosms were determined microscopically without cultivation. This method worked well for in situ monitoring of horizontal gene transfer in addition to tracking the fate of microorganisms released into complex environments. To the best of our knowledge, this is the first study that discusses the coexpression of GFP and DsRed for conjugal gene transfer studies.

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