bioRxiv ScienceSearch

Biology subjects

Widmer, G.

Publications and source records attributed to Widmer, G..

3 recordsLinked to original sources

Deep SNP: An End-to-end Deep Neural Network with Attention-based Localization for Break-point Detection in SNP Array Genomic data

Diagnosis and risk stratification of cancer and many other diseases require the detection of genomic breakpoints as a prerequisite of calling copy number alterations (CNA). This, however, is still challenging and requires time-consuming manual curation. As deep-learning methods outperformed classical state-of-the-art algorithms in various domains and have also been successfully applied to life science problems including medicine and biology, we here propose Deep SNP, a novel Deep Neural Network to learn from genomic data. Specifically, we used a manually curated dataset from 12 genomic single nucleotide polymorphism array (SNPa) profiles as truth-set and aimed at predicting the presence or absence of genomic breakpoints, an indicator of structural chromosomal variations, in windows of 40,000 probes. We compare our results with well-known neural network models as well as Rawcopy though this tool is designed to predict breakpoints and in addition genomic segments with high sensitivity. We show, that Deep SNP is capable of successfully predicting the presence or absence of a breakpoint in large genomic windows and outperforms state-of-the-art neural network models. Qualitative examples suggest that integration of a localization unit may enable breakpoint detection and prediction of genomic segments, even if the breakpoint coordinates were not provided for network training. These results warrant further evaluation of DeepSNP for breakpoint localization and subsequent calling of genomic segments.

genomics

Cryopreservation of Infectious Cryptosporidium parvum Oocysts

Cryptosporidiosis in an enteric infection caused by Cryptosporidium parasites and is a major cause of acute infant diarrhea in the developing world. A major bottleneck to research progress is the lack of methods to cryopreserve Cryptosporidium oocysts, thus requiring routine propagation in laboratory animals. Here, we report a method to cryopreserve C. parvum oocysts by ultra-fast cooling. Cryopreserved oocysts exhibits high viability and robust in vitro excystation, and are infectious to interferon-{gamma} knockout mice. The course of the infection is comparable to what we observe with unfrozen oocysts. Oocyst viability and infectivity is not visibly changed after several weeks of cryogenic storage. Cryopreservation will facilitate the sharing of oocysts from well characterized isolates and transgenic strains among different laboratories.

microbiology

Probiotics enhance susceptibility of mice to cryptosporidiosis

Cryptosporidiosis is a leading cause of diarrhea in infants and immune-compromised individuals. The lack of effective drugs against this enteric infection is motivating research to develop alternative treatments. To this aim, the impact of probiotics on the course of cryptosporidiosis was explored. The native intestinal microbiota of specific pathogen-free immunosuppressed mice was initially depleted with orally administered antibiotics. Then, a commercially available probiotic product intended for human consumption was added (or not) to the drinking water. Probiotic treated and untreated mice were orally infected with Cryptosporidium parvum oocysts. On average, mice treated with probiotic excreted more oocysts, indicative of a more severe infection. The probiotic treatment significantly altered the fecal microbiota, but taxonomic analyses showed no direct association between ingestion of probiotic bacteria and their abundance in fecal microbiota. These results suggest that probiotics indirectly alter the intestinal microenvironment in such a way that favors proliferation of C. parvum. The increase in the relative abundance of facultative anaerobes observed in mice with severe cryptosporidiosis indicates that dysbiosis is a consequence of severe cryptosporidiosis. The increase in the abundance of facultative anaerobes observed in severely infected animals is consistent with analyses of microbiota from individuals infected with other enteric pathogens. The results are significant because they show that C. parvum responds to changes in the intestinal microenvironment induced by a nutritional supplement.\n\nOne Sentence SummaryMice treated with probiotics develop more severe symptoms of cryptosporidiosis.

microbiology