First Report of Brown Rot Caused by Monilinia fructicola on Stored Apple in Serbia

Monilinia fructicola (G. Winter) Honey is a causal agent of brown rot of stone fruits, occasionally affecting pome fruits as well. The pathogen is commonly present in North and South America, Oceania, and Asia, but listed as a quarantine organism in Europe (4). After its first discovery in France in 2001, its occurrence has been reported in Germany, Hungary, Italy, Poland, Romania, Slovenia, Spain, Switzerland, Austria, and the Slovak Republic (1). In February 2011, during a survey for fungal postharvest pathogens in cold storage conditions, apple fruits (Malus domestica Borkh.) grown and stored in the Grocka Region, Serbia, were collected. All pathogens from symptomatic fruits were isolated on potato dextrose agar (PDA). One isolate from apple fruit cv. Golden Delicious with brown rot symptoms was identified as M. fructicola based on morphological and molecular characters. Colonies cultivated on PDA at 22°C in darkness were colorless, but later became grayish, developing mass of spores in concentric rings. Colony margins were even. Conidia were one-celled, limoniform, hyaline, measured 12.19 to 17.37 (mean 13.8) × 8.62 to 11.43 μm (mean 9.9), and were produced in branched monilioid chains (3). Morphological identification was confirmed by PCR (2) using genomic DNA extracted from the mycelium of pure culture, and an amplified product of 535 bp, specific for the species M. fructicola, was obtained. Sequence of the ribosomal (internal transcribed spacer) ITS1-5.8S-ITS2 region was obtained using primers ITS1 and ITS4 and deposited in GenBank (Accession No. JN176564). Control fruits were inoculated with sterile PDA plugs. After 3 days of incubation in plastic containers with high humidity at room temperature, typical symptoms of brown rot developed on inoculated fruits, while control fruits remained symptomless. The isolate recovered from symptomatic fruits showed the same morphological and molecular features of the original isolate. To our knowledge, this is the first report of M. fructicola in Serbia. Further studies are necessary for estimation of economic importance and geographic distribution of this quarantine organism in Serbia. References: (1) R. Baker et al. European Food Safety Authority. Online publication. www.efsa.europa.eu/efsajournal . EFSA J. 9(4):2119, 2011. (2) M.-J. Côté et al. Plant Dis. 88:1219, 2004. (3) J. E. M. Mordue. CMI Descriptions of Pathogenic Fungi and Bacteria. No. 616, 1979. (4) OEPP/EPPO. EPPO A2 List of Pests Recommended for Regulation as Quarantine Pests. Online publication. Version 2010-09. Retrieved from http://www.eppo.org/QUARANTINE/listA2.htm , June 27, 2011. </jats:p

Single-cell Analysis Reveals Inter- and Intratumour Heterogeneity in Metastatic Breast Cancer

Metastasis is the leading cause of cancer-related deaths of breast cancer patients. Some cancer cells in a tumour go through successive steps, referred to as the metastatic cascade, and give rise to metastases at a distant site. We know that the plasticity and heterogeneity of cancer cells play critical roles in metastasis but the precise underlying molecular mechanisms remain elusive. Here we aimed to identify molecular mechanisms of metastasis during colonization, one of the most important yet poorly understood steps of the cascade. We performed single-cell RNA-Seq (scRNA-Seq) on tumours and matched lung macrometastases of patient-derived xenografts of breast cancer. After correcting for confounding factors such as the cell cycle and the percentage of detected genes (PDG), we identified cells in three states in both tumours and metastases. Gene-set enrichment analysis revealed biological processes specific to proliferation and invasion in two states. Our findings suggest that these states are a balance between epithelial-to-mesenchymal (EMT) and mesenchymal-to-epithelial transitions (MET) traits that results in so-called partial EMT phenotypes. Analysis of the top differentially expressed genes (DEGs) between these cell states revealed a common set of partial EMT transcription factors (TFs) controlling gene expression, including ZNF750, OVOL2, TP63, TFAP2C and HEY2. Our data suggest that the TFs related to EMT delineate different cell states in tumours and metastases. The results highlight the marked interpatient heterogeneity of breast cancer but identify common features of single cells from five models of metastatic breast cancer.ISSN:1083-3021ISSN:1573-703

Interleukin 6 transsignaling is a candidate mechanism to drive progression of human DCCs during periods of clinical latency

While thousands of breast cancer cells disseminate and home to bone marrow (BM) until primary surgery, usually less than a handful will succeed in establishing manifest metastases months to years later. Signals and mechanisms determining failure or success of disseminated cancer cells (DCCs) are largely unknown and there is no in vivo model available to study the spontaneous progression and genomic evolution from early bone marrow infiltration to manifestation of bone metastasis, as spontaneous or transgenic mouse models do not generate bone metastases. We therefore profiled DCCs from BM of breast cancer patients long before manifestation of metastasis by RNAseq to identify signals supporting survival or outgrowth of DCCs and identified IL6/PTEN/PI3K signaling as candidate pathway for DCC activation. Since early DCCs often display close-to-normal genomes we used mammary epithelial cells ex vivo isolated from reduction mammoplasties and immortalized pre-malignant breast cancer cell lines as model for functional testing in vitro. Using specific activators and inhibitors of IL6 signaling revealed that IL6 trans, but not classical signaling, regulates stemness of mammary epithelial cells. Moreover, knock-down of PTEN revealed that PI3K/PTEN pathway activation renders cells independent of IL6 trans-signaling. Interestingly, gp130 expression, a pre-requisite for IL6 trans-signaling was found to be down-regulated by bone marrow stromal and endosteal, but not vascular niche cells, and as a consequence the number of cells with stem-like ability was significantly reduced. Consistent with a bottleneck function of microenvironmental DCC control, we found PIK3CA mutations highly associated with late-stage metastatic DCCs and CTCs while generally absent in early DCCs. Our data suggest that the initial steps of metastasis formation depend on microenvironmental signals and are not cancer cell-autonomous