Biology subjects

Jorissen, M.

Publications and source records attributed to Jorissen, M..

4 recordsLinked to original sources

bioRxiv2023

Lifestyle and not density of fish hosts determines parasite distribution over time and space

Despite their important ecological role, questions remain on mechanisms structuring parasite assemblages. We present a simple and endemic host-parasite system of clupeid fishes and monogenean parasites (Kapentagyrus, Dactylogyridae) with contrasting levels of host-specificity from Lake Tanganyika as a model to study parasite distribution patterns and co-infection dynamics in nature. With two parasites, two host species, and three host-parasite combinations between them, this unique system represents the simplest natural host-parasite model that is not trivial. We modelled spatiotemporal dynamics of host-parasite interaction using infection data along the North-South axis of Lake Tanganyika (660 km) over the course of two seasons and four years (1730 fish, 3710 parasites). We found temporal stability of infection, which contrasts with previously reported seasonally driven fluctuations of fish host abundances. We found a difference in spatial structure between the parasite species, confirming that their distributions are only restricted by their most mobile host species. On the host species that is infected by two parasite species, we discovered a positive correlation with host body size for one parasite species, and a negative correlation for the other species. As we also discovered facilitation of infection, this cannot be due to competition. The differences reported between parasite species infecting the same host species further extrapolate the dependence on changes in lifestyle of the host during its ontogenetic development. In conclusion, we show that in a simple, closed system parasite infection dynamics are dependent on a combination of host mobility, host lifestyle changes over ontogenetic development and interspecific interactions between parasites.

ecology↗

bioRxiv2019

Expert Curation of the Human and Mouse Olfactory Receptor Gene Repertoires Identifies Conserved Coding Regions Split Across Two Exons

Olfactory receptor (OR) genes are the largest multi-gene family in the mammalian genome, with over 850 in human and nearly 1500 genes in mouse. The expansion of the OR gene repertoire has occurred through numerous duplication events followed by diversification, resulting in a large number of highly similar paralogous genes. These characteristics have made the annotation of the complete OR gene repertoire a complex task. Most OR genes have been predicted in silico and are typically annotated as intronless coding sequences. Here we have developed an expert curation pipeline to analyse and annotate every OR gene in the human and mouse reference genomes. By combining evidence from structural features, evolutionary conservation and experimental data, we have unified the annotation of these gene families, and have systematically determined the protein-coding potential of each locus. We have defined the non-coding regions of many OR genes, enabling us to generate full-length transcript models. We found that 13 human and 41 mouse OR loci have coding sequences that are split across two exons. These split OR genes are conserved across mammals, and are expressed at the same level as protein-coding OR genes with an intronless coding region. Our findings challenge the long-standing and widespread notion that the coding region of a vertebrate OR gene is contained within a single exon.

genomics↗

bioRxiv2019

A transcriptomic atlas of mammalian olfactory mucosae reveals an evolutionary influence on food odor detection in humans

The mammalian olfactory system displays species-specific adaptations to different ecological niches. To investigate the evolutionary dynamics of olfactory sensory neuron (OSN) sub-types across 95 million years of mammalian evolution, we applied RNA-sequencing of whole olfactory mucosa samples from mouse, rat, dog, marmoset, macaque and human. We find that OSN subtypes representative of all known mouse chemosensory receptor gene families are present in all analyzed species. Further, we show that OSN subtypes expressing canonical olfactory receptors (ORs) are distributed across a large dynamic range and that homologous subtypes can be either highly abundant across all species or species/order-specific. Interestingly, highly abundant mouse and human OSN subtypes detect odorants with similar sensory profiles, and sense ecologically relevant odorants, such as mouse semiochemicals or human key food odorants. Taken together, our results allow for a better understanding of the evolution of mammalian olfaction in mammals and provide insights into the possible functions of highly abundant OSN subtypes in mouse and human.

neuroscience↗

bioRxiv2018

Differential Antiviral Activities of RSV Inhibitors in Human Airway Epithelium

We report the use of reconstituted 3D-human airway epithelium cells of bronchial origin (HuAEC) in an air-liquid interface to study respiratory syncytial virus (RSV) infection and to assess the efficacy of RSV inhibitors in (pre-)clinical development. RSV-A replicates efficiently in HuAEC and viral RNA is shed for weeks after infection. RSV infection reduces the ciliary beat frequency of the ciliated cells as of 4 days post infection, with complete ciliary dyskinesia observed by day 10. Treatment with RSV fusion inhibitors resulted in an antiviral effect only when added at the time of infection. In contrast, the use of replication inhibitors (both nucleoside and non-nucleosides) elicited a marked antiviral effect even when start of treatment was delayed until one or even three days after infection. Levels of the inflammation marker RANTES (mRNA) increased [~]200-fold in infected-untreated cultures (at three weeks post infection), but levels were comparable to those of uninfected cultures in the presence of PC-876, a RSV-replication inhibitor, demonstrating that an efficient antiviral treatment inhibits virus induced inflammation in this model. Overall, HuAEC offer a robust and physiologically relevant model to study RSV replication and to assess the efficacy of antiviral compounds.

microbiology↗