Project description:Roots were collected from young trees outplanted in three regions in Germany (Schorfheide, Swabian Alb, Hainich) and used for RNA extraction. In each region four plots were sampled. Two plants used from each plot. The RNA of the plants per plot was pooled. Four technical replicates were prepared.
Project description:Groundwater-derived microorganisms are known to play an important role in biogeochemical C, S and N cycling. Thereby, the presence and majorly the activity of microorganisms in aquifers affect enormously the nutrient cycling. However, the diversity and their functional capability in natural aquifers are still rare and therefore a better knowledge of the core microbial communities is urgently needed. Metaproteome analysis was applied to characterize the repertoire of microbes in the depth and to identify the key drivers of major biogeochemical processes. Therefore, 1000 L water from the aquifer was sampled by filtration on 0.3 µm glass filters. After protein extraction, proteolytic cleavage and mass spectrometric analysis (Ultimate 3000 nanoRSLC coupled to Q Exactive HF instrument), 3808 protein groups (2371 proteins with ≥2 peptides) were identified from 13,204 peptides. The findings of our study have broad implications for the understanding of aquifer cycling’s which finally leads to a greatly improved understanding of the ecosystem services provided by the microbial communities present in aquifers. In the future, functional results would allow to monitor and to assess pollution effects which would beneficially assist groundwater resource management.
Project description:Members of the bacterial phylum Spirochaetes are primarily studied for their commensal and pathogenic roles in animal hosts. However, Spirochaetes are also frequently detected in anoxic hydrocarbon-contaminated environments but their ecological role in such ecosystems has so far remained unclear. Here we provide a functional trait to these frequently detected organisms with an example of a sulfate-reducing, naphthalene-degrading enrichment culture consisting of a sulfate-reducing deltaproteobacterium Desulfobacterium naphthalenivorans and a novel spirochete Rectinema cohabitans. Using a combination of genomic, proteomic, and physiological studies we show that R. cohabitans grows by fermentation of organic compounds derived from biomass from dead cells (necromass). It recycles the derived electrons in the form of H2 to the sulfate-reducing D. naphthalenivorans, thereby supporting naphthalene degradation and forming a simple microbial loop. We provide metagenomic evidence that equivalent associations between Spirochaetes and hydrocarbon-degrading microorganisms are of general importance in hydrocarbon- and organohalide-contaminated ecosystems. We propose that environmental Spirochaetes form a critical component of a microbial loop central to nutrient cycling in subsurface environments. This emphasizes the importance of necromass and H2-cycling in highly toxic contaminated subsurface habitats such as hydrocarbon-polluted aquifers.
Project description:Mycotoxins are secondary metabolites which are produced by numerous fungi and pose a continuous challenge to the safety and quality of food commodities in South Africa. These toxins have toxicologically relevant effects on humans and animals that eat contaminated foods. In this study, a diagnostic DNA microarray was developed for the identification of the most common food-borne fungi, as well as the genes leading to toxin production. A total of 40 potentially mycotoxigenic fungi isolated from different food commodities, as well as the genes that are involved in the mycotoxin synthetic pathways, were analyzed. For fungal identification, oligonucleotide probes were designed by exploiting the sequence variations of the elongation factor 1-alpha (EF-1 α) coding regions and the internal transcribed spacer (ITS) regions of the rRNA gene cassette. For the detection of fungi able to produce mycotoxins, oligonucleotides directed towards genes leading to toxin production from different fungal strains were identified in data available in the public domain. The oligonucleotides selected for fungal identification and the oligonucleotides specific for toxin producing genes were spotted onto microarray slides. The diagnostic microarray developed can be used to identify potentially mycotoxigenic fungi as well as genes leading to toxin production in both laboratory and food samples offering an interesting potential for microbiological laboratories. Keywords: Development of a diagnostic microarray for the identification of potentially mycotoxigenic fungi as well as genes leading to toxin production, 40 food-borne fungi, mycotoxins Development of a diagnostic array for the identification of food-borne fungi and their potential mycotoxin-producing genes. Oligonucleotide probes to be printed onto the array were designed by exploiting the sequence variations of the elongation factor 1-alpha (EF-1 α) coding regions and the internal transcribed spacer (ITS) regions of the rRNA gene cassette. For the detection of fungi able to produce mycotoxins, oligonucleotides directed towards genes leading to toxin production from different fungal strains were identified in data available in the public domain. Analysis was performed with 40 fungal cultures were obtained from the Agricultural Research Council culture collection (ARC), Pretoria, South Africa.an in-house spotted oligonucleotide microarray. The identity of each fungus was confirmed by standard laboratory procedures. For DNA isolation, the fungal strains were grown on 1.5% malt extract agar at 25°C for 1-2 weeks and total genomic fungal DNA was extracted following the DNA extraction protocol described by Raeder and Broda (1985). The internal transcribed spacer oligonucleotides ITS1, ITS3 and ITS4 were used as a reference for normalization of all spot intensity data.Samples were fluorescently labelled with Cy5 dye by using a Cyâ¢Dye Post-labelling Reactive Dye Pack and wre hybridized to the oligonucleotide microarray overnight. Two biological and one technical replicate (using independent labelling reactions) was performed, each replication consisting of a reverse labelling experiment.