Biology subjects

Heitlinger, E.

Publications and source records attributed to Heitlinger, E..

4 recordsLinked to original sources

bioRxiv2019

Detection and quantification of house mouse Eimeria at the species level - challenges and solutions for the assessment of Coccidia in wildlife

Detection and quantification of coccidia in studies of wildlife can be challenging. Therefore, the prevalence of coccidia is often not assessed at the parasite species level in non-livestock animals. Parasite species-specific prevalences are especially important when studying evolutionary questions in wild populations. We tested whether increased host population density increases the prevalence of individual Eimeria species at the farm level, as predicted by epidemiological theory. We studied free-living commensal populations of the house mouse (Mus musculus) in Germany and established a strategy to detect and quantify Eimeria infections. We show that a novel diagnostic primer targeting the apicoplast genome (Ap5) and coprological assessment after flotation provide complementary detection results increasing sensitivity. Genotyping PCRs confirm detection in a subset of samples and cross-validation of different PCR markers does not indicate a bias towards a particular parasite species in genotyping. We were able to detect double infections and to determine the preferred niche of each parasite species along the distal-proximal axis of the intestine. Parasite genotyping from tissue samples provides an additional indication for the absence of species bias in genotyping amplifications. Three Eimeria species were found infecting house mice at different prevalences: Eimeria ferrisi (16.7%; 95% CI 13.2 - 20.7), E. falciformis (4.2%; 95% CI 2.6 - 6.8) and E. vermiformis (1.9%; 95% CI 0.9 - 3.8). We also find that mice in dense populations are more likely to be infected with E. falciformis and E. ferrisi.\n\nWe provide methods for the assessment of prevalences of coccidia at the species level in rodent systems. We show and discuss how such data can help to test hypotheses in ecology, evolution and epidemiology on a species level.

microbiology↗

bioRxiv2019

Eimeria falciformis BayerHaberkorn1970 and novel wild derived isolates from house mice: differences in parasite lifecycle, pathogenicity and host immune reactions

Species of Eimeria (Apicomplexa:Coccidia) differ in the timing of lifecycle progression and resulting infections vary in host immune reactions and pathology they induce. Eimeria infections in house mice are used as models for basic immunology and the most commonly used isolates have been passaged in laboratory mice for over 50 years. We questioned in how far such isolates are still representative for infections in natural systems.\n\nIn the current study, we address this question by comparing the \"laboratory isolate\" E. falciformis BayerHaberkorn1970 with a novel, wild derived isolate E. falciformis Brandenburg88, and contrast this with another novel wild derived isolate, E. ferrisi Brandenburg64. We compare parasite lifecycle progression. We relate this to immune cell infiltration at the site of infection (in the caecum) and cytokine gene expression in the spleen as a measure of host immune response. We assess host weight loss as a measure of pathogenicity.\n\nA species-specific slower parasite lifecyle progression and higher pathogenicity are observed for E. falciformis vs. E. ferrisi. Host cytokines, in contrast, are expressed at significantly higher level in the spleen of mice infected with the E. falciformis laboratory isolate than in both wild derived isolates, irrespective of the species. Differences in histopathology are observable between all three isolates: The E. falciformis BayerHaberkorn1970 laboratory isolate induces the strongest inflammation and cellular infiltration (with lymphocytes, plasma cells and eosinophilic granulocytes) followed by the wild derived E. falciformis Brandenburg88 isolate. E. ferrisi Brandenburg64 is inducing milder histological changes than both E. falciformis isolates.\n\nIt can be speculated that the serial passaging of E. falciformis BayerHaberkorn1970 has resulted in evolutionary divergence rendering this isolate more virulent in NMRI mice. Caution is needed when findings from experimental infection with laboratory strains should be integrated with observations in natural systems.\n\nHighlightsO_LIE. ferrisi has a shorter pre-patency than wild-derived and laboratory isolates of E. falciformis.\nC_LIO_LIE. ferrisi is less virulent than both E. falciformis isolates and the timing of maximal oocyst shedding relative to host weight loss differs.\nC_LIO_LIThe laboratory strain of E. falciformis induces stronger cytokine expression in the spleen than both wild derived strains of E. falciformis and E. ferrisi.\nC_LIO_LIThe laboratory strain of E. falciformis induces stronger tissue infiltration of immune cells than the wild-derived strain. E. ferrisi infections are associated with the lowest infiltration.\nC_LI

microbiology↗

bioRxiv2019

Dual RNA-Seq meta-analysis in Plasmodium infection

Dual RNA-Seq is the simultaneous transcriptomic analysis of interacting symbionts, for example, in malaria. Potential cross-species interactions identified by correlated gene expression might highlight interlinked signaling, metabolic or gene regulatory pathways in addition to physically interacting proteins. Often, malaria studies address one of the interacting organisms - host or parasite - rendering the other "contamination". Here we perform a meta-analysis using such studies for cross-species expression analysis. We screened experiments for gene expression from host and Plasmodium. Out of 171 studies in Homo sapiens, Macaca mulatta and Mus musculus, we identified 63 potential studies containing host and parasite data. While 16 studies (1950 samples) explicitly performed dual RNA-Seq, 47 (1398 samples) originally focused on one organism. We found 915 experimental replicates from 20 blood studies to be suitable for co-expression analysis and used orthologs for meta-analysis across different host-parasite systems. Centrality metrics from the derived gene expression networks correlated with gene essentiality in the parasites. We found indications of host immune response to elements of the Plasmodium protein degradation system, an antimalarial drug target. We identified well-studied immune responses in the host with our co-expression networks as our approach recovers known broad processes interlinked between hosts and parasites in addition to individual host and parasite protein associations. The set of core interactions represents commonalities between human malaria and its model systems for prioritization in laboratory experiments. Our approach might also allow insights into the transferability of model systems for different pathways in malaria studies. ImportanceMalaria still causes about 400,000 deaths a year and is one the most studied infectious diseases. The disease is studied in mice and monkeys as lab models to derive potential therapeutic intervention in human malaria. Interactions between Plasmodium spp. and its hosts are either conserved across different host-parasite systems or idiosyncratic to those systems. Here we use correlation of gene expression from different RNA-Seq studies to infer common host-parasite interactions across human, mouse and monkey studies. We, firstly, find a set of very conserved interactors, worth further scrutiny in focussed laboratory experiments. Secondly, this work might help assess to which extent experiments and knowledge on different pathways can be transferred from models to humans for potential therapy.

bioinformatics↗

bioRxiv2018

A novel non-invasive method to detect gut barrier related changes during a gastrointestinal nematode infection.

Currently, methods for monitoring changes of gut barrier integrity and the associated immune response via non-invasive means are limited. Therefore, we aimed to develop a novel non-invasive technique to investigate immunological host responses representing gut barrier changes in response to infection. We identified the mucous layer on feces from mice to be mainly composed of exfoliated intestinal epithelial cells. Expression of RELM-{beta}, a gene prominently expressed in intestinal nematode infections, was used as an indicator of intestinal cellular barrier changes to infection. RELM-{beta} was detected as early as 6 days post-infection (dpi) in exfoliated epithelial cells. Interestingly, RELM-{beta} expression also mirrored the quality of the immune response, with higher amounts being detectable in a secondary infection and in high dose nematode infection in laboratory mice. This technique was also applicable to captured worm-infected wild house mice. We have therefore developed a novel non-invasive method reflecting gut barrier changes associated with alterations in cellular responses to a gastrointestinal nematode infection.

immunology↗