Mother-to-Infant Microbial Transmission from Different Body Sites Shapes the Developing Infant Gut Microbiome.

The acquisition and development of the infant microbiome are key to establishing a healthy host-microbiome symbiosis. The maternal microbial reservoir is thought to play a crucial role in this process. However, the source and transmission routes of the infant pioneering microbes are poorly understood. To address this, we longitudinally sampled the microbiome of 25 mother-infant pairs across multiple body sites from birth up to 4 months postpartum. Strain-level metagenomic profiling showed a rapid influx of microbes at birth followed by strong selection during the first few days of life. Maternal skin and vaginal strains colonize only transiently, and the infant continues to acquire microbes from distinct maternal sources after birth. Maternal gut strains proved more persistent in the infant gut and ecologically better adapted than those acquired from other sources. Together, these data describe the mother-to-infant microbiome transmission routes that are integral in the development of the infant microbiome.

Maternal inheritance of bifidobacterial communities and bifidophages in infants through vertical transmission.

BACKGROUND: The correct establishment of the human gut microbiota represents a crucial development that commences at birth. Different hypotheses propose that the infant gut microbiota is derived from, among other sources, the mother's fecal/vaginal microbiota and human milk. RESULTS: The composition of bifidobacterial communities of 25 mother-infant pairs was investigated based on an internal transcribed spacer (ITS) approach, combined with cultivation-mediated and genomic analyses. We identified bifidobacterial strains/communities that are shared between mothers and their corresponding newborns. Notably, genomic analyses together with growth profiling assays revealed that bifidobacterial strains that had been isolated from human milk are genetically adapted to utilize human milk glycans. In addition, we identified particular bacteriophages specific of bifidobacterial species that are common in the viromes of mother and corresponding child. CONCLUSIONS: This study highlights the transmission of bifidobacterial communities from the mother to her child and implies human milk as a potential vehicle to facilitate this acquisition. Furthermore, these data represent the first example of maternal inheritance of bifidobacterial phages, also known as bifidophages in infants following a vertical transmission route.

Short cold storage enhances the anthocyanin contents and level of transcripts related to their biosynthesis in blood oranges.

The health benefits associated with the consumption of anthocyanin-containing foods are extensively documented. Mature fruits of blood oranges and their hybrids are characterized by the presence of these bioactive pigments, the abundance of which can be enhanced by storing fruit at cooling nonfreezing temperature. In this work the effects of short low-temperature exposure (4 °C × 15 days) upon orange anthocyanin content and the expression of structural genes belonging to the pigment biosynthesis pathway were investigated. The results highlight that anthocyanin levels of fruit exposed to cold sharply increase, reaching, after 6 days of storage, a value 8 times higher than that observed in the time zero samples, thus suggesting that fruit with enhanced health-related attributes might be obtained at this storage stage. The analysis of gene expression shows that the amount of transcripts of all considered genes (CM1, PAL, CHS, DFR, ANS, UFGT, and GST) sharply increased after 3-6 days of cold storage, confirming previous data showing that the biosynthesis of anthocyanins is a cold-regulated pathway. By comparing the expression of selected genes (PAL, DFR, and UFGT) between blood and common oranges, it turns out that those genes strictly involved in anthocyanin biosynthesis are not cold responsive in common oranges. Moreover, the data highlight that the EST encoding the transcription factor NAC domain protein is selectively induced by cold in blood oranges but not in common oranges, thus proposing it as a candidate gene specifically involved in blood orange response to cold exposure.

Expression analysis in response to low temperature stress in blood oranges: implication of the flavonoid biosynthetic pathway.

The productivity and the geographical distribution of most commercially important Citrus varieties are markedly affected by environmental low temperatures. As gene engineering has been shown to be a favourable alternative to produce germplasm with improved cold tolerance, a broad group of cold regulated genes have been previously identified from several Citrus spp. By contrast, little information regarding the cold stress response of pigmented sweet orange varieties is available although they might provide a pivotal contribution to define the whole events occurring in cold exposed Citrus fruits. In our work, the transcriptome analysis based on subtractive hybridisation was performed in order to emphasise the overall induction in gene expression after the exposure of blood oranges [(Citrus sinensis) L. Osbeck Tarocco Sciara] to low temperature. The cold induction of several gene expressions was then validated by real-time RT-PCR. Overall, we observed the enhancement of transcripts involved in the defence mechanisms against oxidative damage, osmoregulating processes, lipid desaturation as well as many ESTs implicated in the primary and secondary metabolisms. In particular, the results show that cold stress induces transcriptomic modifications directed towards the increase of flavonoid biosynthesis, including those reactions involved in anthocyanin biosynthesis, as well as of the metabolic pathways supplying it. By comparing the blood orange response to cold stress with those of other plant sources, such as grapefruit, it seems to be similar to that of the chilling acclimated species. Interestingly, among the genes encoding for the regulatory proteins, several transcription factors have been identified for the first time as cold responsive genes in plants, indicating novel investigation lanes which should receive special attention in the future.