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Alkaline earth metal fluoride nanoparticles have been investigated for application in wood protection. Sols of MgF2 and CaF2 were synthesized and their efficacy was tested against fungi and termites (Rehmer 2016, Krahl et al. 2016). The sols were characterized by XRD and SEM. The wood specimens were vacuum impregnated with nanoparticles and then exposed to fungi and termites according to EU certified test conditions. Our results show that wood impregnated with metal fluoride nanoparticles significantly reduce cellulose hydrolysis by fungi and termites. The wood samples were exposed to brown-rot fungi; Coniophora puteana and Poria placenta. Between the two fungi, the overall mass lost due to fungal degradation was lower for treated (MgF2 and CaF2) wood samples exposed to Coniophora puteana. Thus, the metal fluoride nanoparticles impregnated in the wood samples were more efficient in reducing cellulose degradation from Coniophora puteana than from Poria placenta. However the mass loss in samples treated with MgF2 was similar to those treated with CaF2, irrespective of type of fungi. Therefore, it is likely that fungal degradation in treated samples was dependent on the biocidal action of fluorides rather than on the differences in chemical and physical properties of MgF2 and CaF2, respectively. Conversely, for termite exposure, wood samples treated with MgF2 had lower cellulose degradation compared to those treated with CaF2. A possible explanation for this difference in results could be fungi and termites use separate mechanisms for cellulose hydrolysis which will be further investigated. Future experiments include testing the leaching potential of MgF2 and CaF2 nanoparticles from wood. The results from the leaching experiment will test if metal fluoride nanoparticles can provide long-term and environmentally safe protection to wood.
Bacterial infections are a global threat to human health1. Especially nosocomial infections with multidrug-resistant Gram-negative bacteria challenge public health systems and endanger successful treatment of patients in various modern medicine applications as e.g. organ transplant. In the last three decades classical approaches failed to find novel chemical scaffolds suitable for the development of antibiotics.
Insect microbiomes produce potent antibiotics with low toxicity to eukaryotic cells to defend their hosts against entomopathogenic microorganisms2. In order to exploit insect microbiomes efficiently and to identify novel antibiotic producing bacteria, we implemented an high throughput Microfluidics/FACS (fluorescence-associated cell sorting) cultivation and screening pipeline. Here, we present the technical aspects of our pipeline including downstream processing. This includes genomic fingerprinting of identified producer strains, metabolomic analysis and isolation of natural products.
Standardized test methods by which the efficacies of conventional Chemical wood preservatives against insects determine their toxic effects against larvae of wood boring beetles or their feeding prevention by termites. Although alternative control strategies to the application of biocides exist, such as interference with insect behavior during mating or when searching for suitable breeding and feeding sites, their acceptance, too, depends on efficacy evaluation. This is why new test set ups are needed which take behavior modifying control strategies into account. This paper will demonstrate how new laboratory tests must be designed or how existing Standards can be altered to reliably interpret insect behavior including its successful manipulation in a standardized format.
Subterranean termites moving in the peripheral tubular network of their foraging area need to distinguish the trail direction. In a natural gallery or tunnel network of Reticulitermes flavipes the branches at bifurcations generally have an acute angle between them. the resulting obtuse angle from the main trail leading into a branch is preferred by commuting termites. In experiments with artificial gallery forks, termites returning from a food source only neglected the trail junction leading to the nest and preferred the trail to a second food source if the angle to the nest was acute. A right angle to the nest was preferred over a straight way leading to a second food source. This preference to the nest increased when the three branches at trifurcations were arranged equi-angular. This preferred orientation could be attributed to attracting odours from close-by gallery material. Additionally, R. flavipes moved more slowly towards a food source consisting of pine wood than on the way back to the nest, as was shown in artificial one-way galleries. However, the significance of this speed difference remains uncertain because the speed of a homing termite in an artificially reversed trail does not slow down to the speed of a food foraging termite.
Wood-eating termites feed on a diet highly deficient in nitrogen. They must complement their diet with the aid of nitrogen-fixing bacteria. Nitrogen fixation in the gut has been demonstrated, but information about nitrogen-fixing bacteria in pure culture is scarce. From the higher termite Nasutitermes nigriceps the symbiotic bacterial strain M3A was isolated, which thrives in the hindgut contents. The Gram-negative strain exhibited similarities to the species of the genus Ensifer (including Sinorhizobium) on the basis of morphological and physiological/biochemical features. The 16S rRNA gene analysis showed the highest sequence similarity of the isolate M3A to Ensifer adhaerens (>99%; ATCC 33499). The DNADNA hybridization revealed a similarity of 66% with E. adhaerens (NCIMB12342T). In contrast to the type strain the isolate M3A possesses the capacity to nodulate plant roots. This is the first report on the detailed identification of a rhizobia-related strain from the intestinal tract of animals. Strain M3A has been deposited with two culture collections (DSM10169; ATCC BAA-396).