Biology subjects

Pucci, N.

Publications and source records attributed to Pucci, N..

4 recordsLinked to original sources

bioRxiv2026

A bifidobacterial enzyme orchestrates ecology and function of infant gut bacterial community

Human milk oligosaccharides (HMOs) are abundant and structurally diverse glycans that shape the development of infant gut microbiota. Yet, how individual HMOs and bacterial genes drive the community assembly remain elusive. Here, we reconstructed an eight-member infant Bacterial Community (iBaCo) from representing dominant taxa in human infant feces. When individual HMOs were the sole carbohydrate source, they showed deterministic effects on the iBaCo composition and metabolic output. Notably, the tetramer HMO lacto-N-tetraose (LNT), in spite of its identical monomer composition as lacto-N-neotetraose (LNnT), showed a strong effect on maintaining Bifidobacterium breve abundance in iBaCo, whereas LNnT did not. Monoculture growth profiling, proteomics, enzymatic kinetic assay, and molecular docking revealed that {beta}-galactosidase D4BMY8 and the relevant downstream pathways are induced by LNT and that D4BMY8 has substrate preference on LNT over LNnT, enabling a faster growth of Bi. breve and accumulation of acetate and lactate in LNT compared to LNnT. Metabolic flux analysis indicated that the substrate-preference of {beta}-galactosidase D4BMY8 drives the skewed energy cost toward lactate/acetate metabolic output. Finally, the D4BMY8-encoding gene lacZ5 is widely spread in all isolated Bi. breve genomes, but divergently distributed in infant metagenome-assembled Bi. breve genomes. Together, we demonstrated that a single enzyme-substrate interaction could orchestrate the composition and metabolic function of an infant bacterial community, which may contribute to the assembly of dynamic infant gut microbiota. Our integrative approach provides a mechanistic framework for understanding the interaction between diet, microbial community, and infant gut health.

microbiology↗

bioRxiv2025

Microbiota-derived indole metabolites inhibit rotavirus infection in vitro and in vivo and in human infants

Rotavirus (RV) is the leading cause of life-threatening gastroenteritis in children under five despite effective RV vaccines availability, necessitating novel protective strategies for high-risk populations. Gut microbiota can modulate RV susceptibility and vaccine immunogenicity, yet underlying mechanisms are poorly characterized. Here, we demonstrate that microbiota-derived indole metabolites confer protection against RV infection. In healthy adults, higher fecal indole-3-acetic acid (IAA) and indole-3-propionic acid (IPA) levels associated with reduced fecal RV shedding following challenge. In human intestinal enteroids (HIEs), IAA pre-treatment inhibited human RV Wa G1P[8] replication via the aryl hydrocarbon receptor (AhR) pathway. In mice, treatment with AhR agonist indole-3-carbinol (I3C) significantly reduced fecal shedding of murine RV strain EDIM-Cambridge. Finally, Zambian infants with active RV infection exhibited lower fecal IAA and IPA levels than age-matched healthy controls. These findings demonstrate that microbiota-derived AhR ligands consistently inhibit RV infection across three experimental models and hold promise for protecting at-risk pediatric populations.

microbiology↗

bioRxiv2025

Unique ecology of co-occurring functionally and phylogenetically undescribed species in the infant oral microbiome

Early-life oral microbiome development is a complex community assembly process that influences long-term health outcomes. Nevertheless, microbial functions and interactions driving these ecological processes remain poorly understood. In this study, we analyze oral microbiomes from a longitudinal cohort of 24 mother-infant dyads at 1 and 6 months postpartum using shotgun metagenomics. We identify two previously undescribed Streptococcus and Rothia species to be among the most prevalent, abundant and strongly co-occurring members of the oral microbiome of six-month-old infants. To explore the underlying genomic traits enabling this unique lifestyle, we leveraged metagenome-assembled genomes (MAGs) and genome-scale metabolic models (GEMS). Comparative analyses revealed specific genomic and functional characteristics relative to other closely related species and highlighted unique functional features, including genes encoding adhesins and carbohydrate-active enzymes (CAZymes). The observed co-occurrence patterns were further supported by predicted metabolic interactions within a network of co-occurring oral taxa. Metabolic modeling identified potential exchange of key nutrients, particularly malate and lysine, between these species, suggesting metabolic cross-feeding interactions that may explain their co-occurrence across infant oral microbiomes. Overall, this study provides key insights into the functional adaptations and microbial interactions shaping early colonization in the oral cavity. Author SummaryWe investigated how infant oral bacterial communities develop during their first six months of life, with the aim to understand which microbes colonize, how they establish themselves and why they succeed together. Using high throughput DNA sequencing techniques, we analyzed oral samples from 24 mother-infant pairs at one and six months after birth. We found two abundant, but previously unknown bacterial species (one Streptococcus and one Rothia) at six months of age. These bacteria consistently appear together across different babies, suggesting they may depend on each other for survival and growth. By reconstructing the genomes of these bacteria directly from our samples, we discovered specific genetic features that help explain their success in the infant mouth. Streptococcus carries genes that allow it to break down nutrients from breast milk. Rothia has genes that help it rapidly build cell membranes and protect against harmful molecules, while producing nutrients that Streptococcus needs. We predict these bacteria exchange key nutrients like malate and lysine, creating a mutually beneficial partnership. The bacteria seem to cooperate and are predicted to exchange key nutrients like malate and lysine which may help maintain a healthy oral environment by regulating acidity levels, potentially protecting against tooth decay.

genomics↗

bioRxiv2019

Nanopore sequencing for the detection and the identification of Xylella fastidiosa subspecies and sequence types from naturally infected plant material

Xylella fastidiosa (Xf) is a polyphagous gram-negative bacterial plant pathogen that can infect more than 300 plant species. It is endemic in America while, in 2013, Xf subsp. pauca was for the first time reported in Europe on olive tree in the Southern Italy. The availability of fast and reliable diagnostic tools is indispensable for managing current and future outbreaks of Xf. In this work, we used the Oxford Nanopore Technologies (ONT) device MinION platform for detecting and identifying Xf at species, subspecies and Sequence Type (ST) level straight from infected plant material. The study showed the possibility to detect Xf by direct DNA sequencing and identify the subspecies in highly infected samples. In order to improve sensitivity, Nanopore amplicon sequencing was assessed. Using primers within the set of the seven MLST officially adopted for identifying Xf at type strain level, we developed a workflow consisting in a multiple PCR and an ad hoc pipeline to generate MLST consensus after Nanopore-sequencing of the amplicons. The here-developed combined approach achieved a sensitivity higher than real-time PCR allowing within few hours, the detection and identification of Xf at ST level in infected plant material, also at low level of contamination. Originality Significance StatementIn this work we developed a methodology that allows the detection and identification of Xylella fastidiosa in plant using the Nanopore technology portable device MinION. The approach that we develop resulted more sensitive than methods currently used for detecting X. fastidiosa, like real-time PCR. This approach can be extensively used for X. fastidiosa detection and it may pave the road for the detection of other tedious vascular pathogens.

pathology↗