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- Kennedy, K. M., et al.
(author)
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Questioning the fetal microbiome illustrates pitfalls of low-biomass microbial studies
- 2023
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 613:7945, s. 639-649
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Journal article (peer-reviewed)abstract
- Whether the human fetus and the prenatal intrauterine environment (amniotic fluid and placenta) are stably colonized by microbial communities in a healthy pregnancy remains a subject of debate. Here we evaluate recent studies that characterized microbial populations in human fetuses from the perspectives of reproductive biology, microbial ecology, bioinformatics, immunology, clinical microbiology and gnotobiology, and assess possible mechanisms by which the fetus might interact with microorganisms. Our analysis indicates that the detected microbial signals are likely the result of contamination during the clinical procedures to obtain fetal samples or during DNA extraction and DNA sequencing. Furthermore, the existence of live and replicating microbial populations in healthy fetal tissues is not compatible with fundamental concepts of immunology, clinical microbiology and the derivation of germ-free mammals. These conclusions are important to our understanding of human immune development and illustrate common pitfalls in the microbial analyses of many other low-biomass environments. The pursuit of a fetal microbiome serves as a cautionary example of the challenges of sequence-based microbiome studies when biomass is low or absent, and emphasizes the need for a trans-disciplinary approach that goes beyond contamination controls by also incorporating biological, ecological and mechanistic concepts.
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- Mihalca, A.D., et al.
(author)
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Severe Granulomatous Lesions in Several Organs from Eustrongylides Larvae in a Free-ranging Dice Snake, Natrix tessellata
- 2007
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In: Veterinary Pathology. - : SAGE Publications. - 0300-9858 .- 1544-2217. ; 44:1, s. 103-105
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Journal article (peer-reviewed)abstract
- During an extensive study regarding the epidemiology of larval Eustrongylides infestation in a free-ranging endangered population of dice snakes (Natrix tessellata) from Histria, Romania, an adult female was euthanized to evaluate pathologic changes. Parasites appeared as nodules at various locations: in subcutaneous connective tissues, on the serosae of the intestines and liver. Histologic sections revealed nematode larvae surrounded by a capsule, forming a parasitic granuloma with 3 layers: macrophage layer, lymphocyte layer, and fibrous capsule. Differences between newly formed and mature granulomas consisted mainly in the eosinophilic infiltration. Other types of parasitic granulomas of reptiles are discussed in comparison with our findings.
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