115 research outputs found
Detection of Bacterial Endospores in Soil by Terbium Fluorescence
Spore formation is a survival mechanism of microorganisms when facing unfavorable environmental conditions resulting in âdormantâ states. We investigated the occurrence of bacterial endospores in soils from various locations including grasslands (pasture, meadow), allotment gardens, and forests, as well as fluvial sediments. Bacterial spores are characterized by their high content of dipicolinic acid (DPA). In the presence of terbium, DPA forms a complex showing a distinctive photoluminescence spectrum. DPA was released from soil by microwaving or autoclaving. The addition of aluminium chloride reduced signal quenching by interfering compounds such as phosphate. The highest spore content (up to 109 spores per gram of dry soil) was found in grassland soils. Spore content is related to soil type, to soil depth, and to soil carbon-to-nitrogen ratio. Our study might provide a basis for the detection of âhot spotsâ of bacterial spores in soil
Notation als Zeichensystem. Ein Ansatz zu einer Semiotik der traditionellen Musikaufzeichnung
Frßher Notendruck in deutschsprachigen Ländern: Die Materialität der Regensburger Missalien
Musik im sakralen Raum ist ein zentrales Thema der älteren Musikgeschichte, sowohl des Mittelalters als auch der FrĂźhen Neuzeit. Wir denken dabei an die groĂartige mehrstimmige Musik, die von hochprofessionellen ChĂśren im Kirchenraum aufgefĂźhrt wurde, aber ebenso an die Orgel, deren Klänge den weiten Raum durchfluteten. Musikalische Quellen wie groĂ dimensionierte, oft prachtvoll ausgefĂźhrte ChorbĂźcher und viel bescheidenere Orgeltabulaturen haben diese Musik seit rund 500 Jahren fĂźr uns bewahrt. Die auffĂźhrungspraktischen Umstände und Bedingungen sind durch Beschreibungen und insbesondere durch ikonographische Darstellungen aus der Zeit annähernd erschlieĂbar
The Predictability of Phytophagous Insect Communities: Host Specialists as Habitat Specialists
The difficulties specialized phytophagous insects face in finding habitats with an appropriate host should constrain their dispersal. Within the concept of metacommunities, this leads to the prediction that host-plant specialists should sort into local assemblages according to the local environmental conditions, i.e. habitat conditions, whereas assemblages of host-plant generalists should depend also on regional processes. Our study aimed at ranking the importance of local environmental factors and species composition of the vegetation for predicting the species composition of phytophagous moth assemblages with either a narrow or a broad host range. Our database consists of 351,506 specimens representing 820 species of nocturnal Macrolepidoptera sampled between 1980 and 2006 using light traps in 96 strict forest reserves in southern Germany. Species were grouped as specialists or generalists according to the food plants of the larvae; specialists use host plants belonging to one genus. We used predictive canonical correspondence and co-correspondence analyses to rank the importance of local environmental factors, the species composition of the vegetation and the role of host plants for predicting the species composition of host-plant specialists and generalists. The cross-validatory fit for predicting the species composition of phytophagous moths was higher for host-plant specialists than for host-plant generalists using environmental factors as well as the composition of the vegetation. As expected for host-plant specialists, the species composition of the vegetation was a better predictor of the composition of these assemblages than the environmental variables. But surprisingly, this difference for specialized insects was not due to the occurrence of their host plants. Overall, our study supports the idea that owing to evolutionary constraints in finding a host, host-plant specialists and host-plant generalists follow two different models of metacommunities: the species-sorting and the mass-effect model
Chiral macrocyclic terpyridine complexes
The syntheses of novel chiral M( II ) bis(terpyridine) cage complexes Fe(L1) 2 -c and Ru(L1) 2 -c are described. The extraordinary design of the precursors Fe(L1) 2 and Ru(L1) 2 allows perfect preorganization for the final closing step. Due to the rigidity of the spacers between the two terpyridine moieties, the two isolated enantiomers barely racemize at room temperature in solution. The stable and axially chiral bis(terpyridine) Fe( II ) and Ru( II ) complexes were fully characterized by NMR-spectroscopy, UV-Vis spectroscopy, electrochemical measurements, high resolution mass spectrometry, circular dichroism measurements, and X-ray structural analysis
Watermarks and Where to Find Them: Digitisation, Recognition, and Automated Clustering of Watermarks in the Music Manuscripts of Franz Schubert
Our project focuses on watermarks found in the music manuscripts of Franz Schubert. The endeavour incorporates thermography, machine learning and signal processing to produce digitized watermarks for databases and manuscript descriptions as well as to curtail the approximate dating of some undated autographs. By applying fingerprint recognition software to the acquired thermographic watermark images, a new method for automatic clustering will be established. MEI will be used as the systemâs foundation for data presentation online and to guarantee long-term archiving and open source access. As MEI currently does not provide a best practice for encoding watermark information, a standardized form will be developed in collaboration with the community
Salmonella Biofilm Formation on Aspergillus niger Involves Cellulose â Chitin Interactions
Salmonella cycles between host and nonhost environments, where it can become an active member of complex microbial communities. The role of fungi in the environmental adaptation of enteric pathogens remains relatively unexplored. We have discovered that S. enterica Typhimurium rapidly attaches to and forms biofilms on the hyphae of the common fungus, Aspergillus niger. Several Salmonella enterica serovars displayed a similar interaction, whereas other bacterial species were unable to bind to the fungus. Bacterial attachment to chitin, a major constituent of fungal cell walls, mirrored this specificity. Pre-incubation of S. Typhimurium with N-acetylglucosamine, the monomeric component of chitin, reduced binding to chitin beads by as much as 727-fold and inhibited attachment to A. niger hyphae considerably. A cellulose-deficient mutant of S. Typhimurium failed to attach to chitin beads and to the fungus. Complementation of this mutant with the cellulose operon restored binding to chitin beads to 79% of that of the parental strain and allowed for attachment and biofilm formation on A. niger, indicating that cellulose is involved in bacterial attachment to the fungus via the chitin component of its cell wall. In contrast to cellulose, S. Typhimurium curli fimbriae were not required for attachment and biofilm development on the hyphae but were critical for its stability. Our results suggest that celluloseâchitin interactions are required for the production of mixed Salmonella-A. niger biofilms, and support the hypothesis that encounters with chitinaceous alternate hosts may contribute to the ecological success of human pathogens
In-Depth Characterisation of Retinal Pigment Epithelium (RPE) Cells Derived from Human Induced Pluripotent Stem Cells (hiPSC)
Induced pluripotent stem cell (iPSC)-derived retinal pigment epithelium (RPE) has widely been appreciated as a promising tool to model human ocular disease emanating from primary RPE pathology. Here, we describe the successful reprogramming of adult human dermal fibroblasts to iPSCs and their differentiation to pure expandable RPE cells with structural and functional features characteristic for native RPE. Fibroblast cultures were established from skin biopsy material and subsequently reprogrammed following polycistronic lentiviral transduction with OCT4, SOX2, KLF4 and L-Myc. Fibroblast-derived iPSCs showed typical morphology, chromosomal integrity and a distinctive stem cell marker profile. Subsequent differentiation resulted in expandable pigmented hexagonal RPE cells. The cells revealed stable RNA expression of mature RPE markers RPE65, RLBP and BEST1. Immunolabelling verified localisation of BEST1 at the basolateral plasma membrane, and scanning electron microscopy showed typical microvilli at the apical side of iPSC-derived RPE cells. Transepithelial resistance was maintained at high levels during cell culture indicating functional formation of tight junctions. Secretion capacity was demonstrated for VEGF-A. Feeding of porcine photoreceptor outer segments revealed the proper ability of these cells for phagocytosis. IPSC-derived RPE cells largely maintained these properties after cryopreservation. Together, our study underlines that adult dermal fibroblasts can serve as a valuable resource for iPSC-derived RPE with characteristics highly reminiscent of true RPE cells. This will allow its broad application to establish cellular models for RPE-related human diseases
Nebraska\u27s Advantage: Productive Agriculture and Bountiful Natural Resources
Nebraska\u27s Advantage: Productive Agriculture and Bountiful Natural Resources
You canât talk about healthy production systems and natural resource systems without also thinking about the resilience. We need to harmonize production agriculture in a way that ensures the resilience of our natural ecosystems and rural communitiesâall while addressing bundles of grand challenges
Evaluation of the addition of glycerol to Cupriavidus necator culture medium over Poly(3-hydroxybutyrate) production
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