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- Pollen (4)
- Ecology and environmental sciences (2)
- Infrared spectroscopy (2)
- MALDI-TOF MS (2)
- Alnus (1)
- Betula (1)
- Betulaceae (1)
- Classification (1)
- Corylus (1)
- FTIR (1)
Organisationseinheit der BAM
Populations of genetically identical cells can display marked variation in phenotypic traits; such variation is termed phenotypic heterogeneity. Here, we investigate the effect of substrate and electron donor limitation on phenotypic heterogeneity in N2 and CO2 fixation in the green sulphur bacterium Chlorobium phaeobacteroides. We grew populations in chemostats and batch cultures and used stable isotope labelling combined with nanometer‐scale secondary ion mass spectrometry (NanoSIMS) to quantify phenotypic heterogeneity. Experiments in H2S (i.e. electron donor) limited chemostats show that varying levels of NH4+ limitation induce heterogeneity in N2 fixation. Comparison of phenotypic heterogeneity between chemostats and batch (unlimited for H2S) populations indicates that electron donor limitation drives heterogeneity in N2 and CO2 fixation. Our results demonstrate that phenotypic heterogeneity in a certain metabolic activity can be driven by different modes of limitation and that heterogeneity can emerge in different metabolic processes upon the same mode of limitation. In conclusion, our data suggest that limitation is a general driver of phenotypic heterogeneity in microbial populations.
Die Mikro- und Nanotechnologie gehört zu den Schlüsseltechnologien des 21. Jahrhunderts mit hohen Wachstumsprognosen, wie auch die im Auftrag des BMBF durchgeführte Studie “Nanotechnologie als wirtschaftlicher Wachstumsmarkt” von 2004 ausführlich darstellt. Aus diesem Trend resultiert ein steigender Bedarf an Messsystemen, die Nanostrukturen prozessnah bzw. im Fertigungsprozess charakterisieren können. Virtuelle Messgeräte liefern Erkenntnisse zur Entwicklung neuartiger Messsysteme, Analyse und Optimierung bestehender Verfahren sowie die Bestimmung der Messunsicherheit und modellbasierten Korrektur systematischer Fehler. Der virtuelle Messprozess umfasst neben dem Messmittel auch die Probe und die Wechselwirkungen zwischen beiden. In diesem Beitrag werden virtuelle Messgeräte vorgestellt sowie deren Anwendung diskutiert.
The analysis of pollen chemical composition is important to many fields, including agriculture, plant physiology, ecology, allergology, and climate studies. Here, the potential of a combination of different spectroscopic and spectrometric methods regarding the characterization of small biochemical differences between pollen samples was evaluated using multivariate statistical approaches. Pollen samples, collected from three populations of the grass Poa alpina, were analyzed using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, surface enhanced Raman scattering (SERS), and matrix assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). The variation in the sample set can be described in a hierarchical framework comprising three populations of the same grass species and four different growth conditions of the parent plants for each of the populations. Therefore, the data set can work here as a model system to evaluate the classification and characterization ability of the different spectroscopic and spectrometric methods. ANOVA Simultaneous Component Analysis (ASCA) was applied to achieve a separation of different sources of variance in the complex sample set. Since the chosen methods and sample preparations probe different parts and/or molecular constituents of the pollen grains, complementary information about the chemical composition of the pollen can be obtained. By using consensus principal component analysis (CPCA), data from the different methods are linked together. This enables an investigation of the underlying global information, since complementary chemical data are combined. The molecular information from four spectroscopies was combined with phenotypical information gathered from the parent plants, thereby helping to potentially link pollen chemistry to other biotic and abiotic parameters.
MALDI time-of-flight mass spectrometry (MALDI-TOF MS) has become a widely used tool for the classification of biological samples. The complex chemical composition of pollen grains leads to highly specific, fingerprint-like mass spectra, with respect to the pollen species. Beyond the species-specific composition, the variances in pollen chemistry can be hierarchically structured, including the level of different populations, of environmental conditions or different genotypes. We demonstrate here the sensitivity of MALDI-TOF MS regarding the adaption of the chemical composition of three Poaceae (grass) pollen for different populations of parent plants by analyzing the mass spectra with partial least squares discriminant analysis (PLS-DA) and principal component analysis (PCA). Thereby, variances in species, population and specific growth conditions of the plants were observed simultaneously. In particular, the chemical pattern revealed by the MALDI spectra enabled discrimination of the different populations of one species. Specifically, the role of environmental changes and their effect on the pollen chemistry of three different grass species is discussed. Analysis of the Group formation within the respective populations showed a varying influence of plant genotype on the classification, depending on the species, and permits conclusions regarding the respective rigidity or plasticity towards environmental changes.
1. Fourier transform infrar ed (FTIR) spectroscopy enables chemical analysis of pollen samples for plant phenotyping to stud y plant–environment interactions, such as influence of climate change or pathogens. However, current approach, such as microspectrosc opy and attenuated total refle ction spectrosco py, doe s not allow fo r high-throughput protocols. This st udy at hand suggests a new sp ectroscopic method for high-throughp ut characterization of pollen.
2. Samples were measured as thin films of pollen fragments using a Bruker FTIR spe ctrometer with a high-throughput eXTension (HTS-XT) unit employing 384-well plates. In total, 146 pollen samples, belonging to 31 different pollen species of Fagaceae and Betulaceae and collected during three consecutive years (2012–2014) at locations in Croatia, Germany and Norway, were analysed. Critical steps in the sample preparation and measurement, such as variabilities between technical replicates, between microplates and between spectrometers, were studied.
3. Measurement variations due to sample preparation, microplate holders and instrumentation were low, and thus allowed differentiation of samples with respect to phylogeny and biogeography. The spectral variability for a ran ge of Fagales spec ies (Fagus, Quercus, Betula, Corylus, Alnus and Ostrya) showed high-species-specific differences in pollen’s chemical composition due to eithe r location or year. Statistically significant inter-annual and locational differences in the pollen spectra indicate that pollen chemical composition has high phenotypic plasticity and is influenced by local climate conditions. The variations in composition are connected to lipids, proteins, carbohydrates and sporopollenins that play crucial ro les in cold and desiccation tolerance, protection against UV radiation and as material and energy reserves.
4. The results of this study demonstrate the value of high-throughput FTIR approach for the systematic collection of data on ecosystems. The novel FTIR approach offers fast, reliable and economical screening of large number of samples by semi-automated methodology. The high-throughput approach could provide crucial understanding on plant–climate interactions with respect to biochemical variation within genera, species and populations.
1. Fourier transform infrared (FTIR) spectroscopy enables chemical analysis of pollen samples for plant phenotyping to study plant–environment interactions, such as influence of climate change or pathogens.However, current approach, such as microspectroscopy and attenuated total reflection spectroscopy, does not allow for highthroughput protocols. This study at hand suggests a new spectroscopic method for high-throughput characterization of pollen.
2. Samples were measured as thin films of pollen fragments using a Bruker FTIR spectrometer with a highthroughput eXTension (HTS-XT) unit employing 384-well plates. In total, 146 pollen samples, belonging to 31 different pollen species of Fagaceae and Betulaceae and collected during three consecutive years (2012–2014) at locations in Croatia, Germany and Norway, were analysed. Critical steps in the sample preparation and measurement, such as variabilities between technical replicates, between microplates and between spectrometers, were studied.
3. Measurement variations due to sample preparation, microplate holders and instrumentation were low, and thus allowed differentiation of samples with respect to phylogeny and biogeography. The spectral variability for a range of Fagales species (Fagus, Quercus, Betula, Corylus, Alnus and Ostrya) showed high-species-specific differences in pollen’s chemical composition due to either location or year. Statistically significant inter-annual and locational differences in the pollen spectra indicate that pollen chemical composition has high phenotypic plasticity and is influenced by local climate conditions. The variations in composition are connected to lipids, proteins, carbohydrates and sporopollenins that play crucial roles in cold and desiccation tolerance, protection against UVradiation and asmaterial and energy reserves.
4. The results of this study demonstrate the value of high-throughput FTIR approach for the systematic collection of data on ecosystems. The novel FTIR approach offers fast, reliable and economical screening of large number of samples by semi-automated methodology. The high-throughput approach could provide crucial understanding on plant–climate interactions with respect to biochemical variation within genera, species and populations.
In the current study, the tribological properties of TiC-based coatings paired with polycrystalline alumina under unlubricated sliding conditions were investigated in order to demonstrate the technological and engineering potential of such coatings. (Ti,Mo)(C,N)-Co coatings were prepared from an agglomerated and sintered spray powder by HVOF spraying using JP-5000 equipment. Cr3C2-NiCr coatings were studied for comparison. Sliding wear tests were performed over the temperature range from 23°C to 800°C with sliding speeds in the range 0.3-3 m/s, a wear distance of 5000 m and a normal force of 10 N. Wear rates of coatings and sintered alumina counterparts were measured separately. Compared with Cr3C2-NiCr coatings, (Ti,Mo)(C,N)-Co coatings showed significantly lower total wear rates, corresponding to those found in the region of mixed/boundary lubrication. With few exceptions, the coefficients of friction were found to be lower for (Ti,Mo)(C,N)-Co coatings than for Cr3C2-NiCr coatings. After tests were performed, the coating microstructures were studied by optical microscopy and SEM. The oxide scales formed on the coating surfaces were investigated by SEM and X-ray diffraction. Comparison of the total wear rates of the couples consisting of sintered alumina and a (Ti,Mo)(C,N)-Co coating with those of other alumina-ceramic and hardmetal-hard metal tribological systems demonstrates the immense potential of TiC-based coatings for sliding wear applications.