Biology subjects

Husso, A.

Publications and source records attributed to Husso, A..

3 recordsLinked to original sources

bioRxiv2020

The composition of the microbiota in the full-term fetal gut and amniotic fluid: a bovine caesarean section study

The fetal development of the intestinal immune system is stimulated by the maternal microbiota, but it is still unclear whether viable bacteria exist in the healthy fetus. Analysis of such low microbial biomass environments are challenging due to contamination issues. The aims of the current study were to assess the bacterial load and characterize the bacterial composition of the amniotic fluid and meconium of full-term calves, leading to a better knowledge of prenatal bacterial seeding of the fetal intestine. Amniotic fluid and rectal meconium samples were collected during and immediately after elective caesarean section, performed in 25 Belgian Blue cow-calf couples. The samples were analyzed by qPCR, bacterial culture using GAM agar and 16S rRNA gene amplicon sequencing. To minimize the effects of contaminants, we included multiple technical controls and stringently filtered the 16S rRNA gene sequencing data to exclude putative contaminant sequences. The meconium samples contained a significantly higher amount of bacterial DNA than the negative controls and 5 of 24 samples contained culturable bacteria. In the amniotic fluid, the amount of bacterial DNA was not significantly different from the negative controls and all samples were culture negative. Bacterial sequences were identified in both sample types and were primarily of phyla Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria, with some individual variation. We conclude that most calves encounter in utero maternal-fetal transmission of bacterial DNA, but the amount of bacterial DNA is low and viable bacteria are rare.

microbiology↗

bioRxiv2020

Metabolomic signature of the maternal microbiota in the fetus

The maternal microbiota affects the development of the offspring by microbial metabolites translocating to the fetus. We investigated samples of placenta, fetal intestine and brain from germ-free (GF) and specific pathogen free (SPF) mouse dams by non-targeted metabolic profiling. One hundred one annotated metabolites and altogether 3680 molecular features were present in significantly different amounts in the placenta and/or fetal organs of GF and SPF mice. The concentrations of more than half of the annotated and differentially expressed metabolites were lower in the GF organs, suggesting their microbial origin or a metabolic response of the host to the presence of gut microbiota. The clearest separation was observed in the placenta. Metabolites that were detected in lower amounts in the fetal organs in the GF mice included 5-aminovaleric acid betaine, trimethylamine N-oxide, catechol-O-sulphate, hippuric and pipecolic acid. Derivatives of the amino acid tryptophan, such as kynurenine, 3-indolepropionic acid and hydroxyindoleacetic acid, were also decreased in the absence of microbiota. Several metabolites had higher levels in the GF mice. These could be precursors of microbial metabolites or indicators of host metabolic response to the absence of gut microbiota. Ninety-nine molecular features were only detected in the SPF mice, suggesting the existence of yet unidentified microbially modified metabolites that potentially influence fetal development.

microbiology↗

bioRxiv2019

The composition of the perinatal intestinal microbiota in horse

The establishment of the intestinal microbiota is critical for the digestive and immune systems. We studied the early development of the microbiota in horse, a hindgut fermenter, from birth until 7 days of age, by qPCR and 16S rRNA gene amplicon sequencing. To evaluate initial sources of foal microbiota, we characterized dam fecal, vaginal and oral microbiotas. We utilised an amplicon sequence variant (ASV) based pipeline to maximize resolution and reproducibility. Stringent ASV filtering based on prevalence and abundance in samples and controls purged reagent contaminants while preserving intestinal taxa. The newborn rectum contained small amounts of diverse bacterial DNA, with a profile closer to mare feces and vagina than mouth. 24 hours after birth, the intestine was colonized by Firmicutes and Proteobacteria, some foals dominated by a single genus. At day 7, the phylum-level composition resembled adult feces but genera were different. The mare vaginal microbiota contributed to 24 h and 7 day microbiotas. It contained few lactobacilli, with Corynebacterium, Porphyromonas, Campylobacter and Helcococcus as the most abundant genera. In the oral mucosa, Gemella was extremely abundant. Our observations suggest that bacteria or bacterial components translocate to the equine fetus, but the intestinal microbiota changes rapidly after birth.

microbiology↗