Environmental Filtering Drives Fungal Phyllosphere Community in Regional Agricultural Landscapes.

To adapt to climate change, several agricultural strategies are currently being explored, including a shift in land use areas. Regional differences in microbiome composition and associated phytopathogens need to be considered. However, most empirical studies on differences in the crop microbiome focused on soil communities, with insufficient attention to the phyllosphere. In this study, we focused on wheat ears in three regions in northeastern Germany (Magdeburger Börde (MBB), Müncheberger Sander (MSA), Uckermärkisches Hügelland (UKH)) with different yield potentials, soil, and climatic conditions. To gain insight into the fungal community at different sites, we used a metabarcoding approach (ITS-NGS). Further, we examined the diversity and abundance of Fusarium and Alternaria using culture-dependent and culture-independent techniques. For each region, the prevalence of different orders rich in phytopathogenic fungi was determined: Sporidiobolales in MBB, Capnodiales and Pleosporales in MSA, and Hypocreales in UKH were identified as taxonomic biomarkers. Additionally, F. graminearum was found predominantly in UKH, whereas F. poae was more abundant in the other two regions. Environmental filters seem to be strong drivers of these differences, but we also discuss the possible effects of dispersal and interaction filters. Our results can guide shifting cultivation regions to be selected in the future concerning their phytopathogenic infection potential.

Co-Cultivation of Fusarium, Alternaria, and Pseudomonas on Wheat-Ears Affects Microbial Growth and Mycotoxin Production.

Mycotoxigenic fungal pathogens Fusarium and Alternaria are a leading cause of loss in cereal production. On wheat-ears, they are confronted by bacterial antagonists such as pseudomonads. Studies on these groups' interactions often neglect the infection process's temporal aspects and the associated priority effects. In the present study, the focus was on how the first colonizer affects the subsequent ones. In a climate chamber experiment, wheat-ears were successively inoculated with two different strains (Alternaria tenuissima At625, Fusarium graminearum Fg23, or Pseudomonas simiae Ps9). Over three weeks, microbial abundances and mycotoxin concentrations were analyzed and visualized via Self Organizing Maps with Sammon Mapping (SOM-SM). All three strains revealed different characteristics and strategies to deal with co-inoculation: Fg23, as the first colonizer, suppressed the establishment of At625 and Ps9. Nevertheless, primary inoculation of At625 reduced all of the Fusarium toxins and stopped Ps9 from establishing. Ps9 showed priority effects in delaying and blocking the production of the fungal mycotoxins. The SOM-SM analysis visualized the competitive strengths: Fg23 ranked first, At625 second, Ps9 third. Our findings of species-specific priority effects in a natural environment and the role of the mycotoxins involved are relevant for developing biocontrol strategies.

Optimized creation of glioblastoma patient derived xenografts for use in preclinical studies.

BACKGROUND: Glioblastoma multiforme (GBM) is the most common and lethal brain tumor in adults, highlighting the need for novel treatment strategies. Patient derived xenografts (PDX) represent a valuable tool to accomplish this task. METHODS: PDX were established by implanting GBM tissue subcutaneously. Engraftment success was compared between NMRI Foxn1nu and NOD/SCID as well as between fresh and cryopreserved tissue. Established PDX were analyzed histologically and molecularly. Five PDX were experimentally treated with different drugs to assess their potential for preclinical drug testing. RESULTS: Establishment of PDX was attempted for 36 consecutive GBM cases with an overall success rate of 22.2% in NMRI Foxn1nu mice. No difference was observed between fresh or cryopreserved (20-1057 days) tissue in direct comparison (n = 10 cases). Additionally, engraftment was better in NOD/SCID mice (38.8%) directly compared to NMRI Foxn1nu mice (27.7%) (n = 18 cases). Molecular data and histology of the PDX compare well to the primary GBM. The experimental treatment revealed individual differences in the sensitivity towards several clinically relevant drugs. CONCLUSIONS: The use of vitally frozen GBM tissue allows a more convenient workflow without efficiency loss. NOD/SCID mice appear to be better suited for initial engraftment of tumor tissue compared to NMRI Foxn1nu mice.

Improved Treatment of MT-3 Breast Cancer and Brain Metastases in a Mouse Xenograft by LRP-Targeted Oxaliplatin Liposomes.

The anti-cancer drug oxaliplatin (OxP) has rarely been used to treat breast carcinoma, as it cannot cross the BBB to treat the frequently subsequent brain metastases. Here, we encapsulated OxP in liposomes prepared to reduce side effects and to simultaneously treat primary tumor and brain metastasis. The angiopep LRP-receptor ligand was bound to the vesicular surface for targeting. Targeted and non-targeted OxP liposomes were tested in vitro (binding, uptake, and transcytosis) and in vivo. Liposomes contained 0.65 mg OxP/mL, their mean diameter was 165 nm, and they released 50% of OxP within 8 days at 4 degrees C and within 22 h at 36 degrees C. MDCK cells were used for uptake and transcytosis quantification. Compared to non-targeted liposomes, targeted liposomes showed 12-fold greater uptake, and 2.25-fold higher transcytosis. In vivo efficacy was tested using human MT-3 breast cancer cells transplanted subcutaneously and intracerebrally into female nude mice, and tumor growth inhibition was measured. OxP was injected (6 mg OxP/kg) four times. The best results were obtained with targeted liposomes (T/C: 21% for subcutaneous and 50% for intracerebral). OxP liposomes with a fluid membrane all inhibited MT-3 tumors significantly better than free OxP, with no significant difference between targeted and non-targeted liposomes. The therapeutic effect was accompanied with strong leukopenia and mild thrombocytopenia with all formulations. The newly developed OxP liposomes significantly improved the treatment of subcutaneously and intracerebrally growing breast cancer, but the targeted angiopep-equipped liposomes showed no superior effect in vivo.