Biology subjects

Quagliariello, A.

Publications and source records attributed to Quagliariello, A..

6 recordsLinked to original sources

bioRxiv2025

From microbiome to sperm motility traits: An inside out perspective

Growing interest in the relationship between microbiome composition and host biology has revealed the many ways host-associated microbes influence physiology, ecology, and evolution. However, microbial communities associated with reproductive organs - and their roles in reproduction - remain poorly understood. Here, we characterized the skin- and ejaculate-associated microbiomes in an internally fertilizing fish and tested whether microbial diversity and specific bacterial taxa correlate with sperm motility traits key for reproductive success. We used the guppy (Poecilia reticulata), a well-established model in ecology and evolutionary biology with well-characterised reproductive physiology. In guppies, sperm velocity is a validated predictor of male reproductive performance, making them a powerful system for exploring microbiome-fertility interactions. Our analyses reveal a correlation between skin microbiome diversity and sperm performance. Notably, increased skin microbiome total richness is associated with reduced sperm velocity, whereas no significant associations were detected for ejaculate-associated microbiomes. We also identified bacterial taxa across both tissues that were positively or negatively linked with sperm performance. These findings suggest that, while the ejaculate-associated microbiome may directly influence sperm traits, the skin microbiome could serve as a proxy for reproductive potential by reflecting systemic physiological and immunological states associated with fertility.

microbiology↗

bioRxiv2025

Characterization and description of Clostridium filamentum ETTB, a novel gut bacterium with TLR5 modulating properties

The Clostridium genus is highly heterogeneous, encompassing numerous species and strains, many of which remain to be isolated and characterized to better understand their relationship to host physiology. This study aimed to isolate and characterize novel bacterial species within the Clostridium genus and explore their potential links to host health. Under microaerophilic conditions, we isolated and characterized three bacterial isolates belonging to a new anaerobic Clostridium species, designating Clostridium sp. DSM 115107 (Clostridium filamentum ETTB3) as the type strain. C. filamentum ETTB isolates are rod- to filament-shaped, Gram-positive bacteria and exhibit poor growth when cultured on rich media such as LYBHI. Genome sequencing and phylogenetic analysis revealed that C. filamentum ETTB belongs to the Clostridium genus and clusters closely with Clostridium saudiense JCC. Interestingly, C. filamentum ETTB has a significantly smaller genome compared to C. saudiense JCC containing a reduced repertoire of genes involved in carbohydrate degradation and amino acid synthesis and a larger number of genes related to cell motility, including an additional copy of the fliC gene. Unlike C. saudiense, C. filamentum ETTB adopted a filamentous morphology when in contact with Caco-2 cells and stimulate the TLR5 pathway in Caco-2 cells. Metagenomics analysis revealed that C. filamentum ETTB is present in both industrialized and non-industrialized populations, although the relative abundance varying considerably between and within individuals. Our study identifies a novel bacterial strain adapted for the human gut that has the potential to influence host immune response by activating TLR5 pathway.

microbiology↗

bioRxiv2024

Generating gnotobiotic bivalves: a new method on Manila clam (Ruditapes philippinarum)

The microbiome, which encompasses microbial communities associated with animal hosts, exerts a profound impact on host physiology and ecosystem dynamics. The application of advanced sequencing technologies has enabled researchers to investigate the composition of microbiomes across a range of hosts and environments. While correlating microbial composition with health outcomes has been a priority, interpreting such data requires caution to avoid overemphasizing the roles of microbes. Understanding microbial influence demands mechanistic insights, which are often elucidated through gnotobiology. Despite their limitations in representing animal diversity, model organisms offer the advantage of reproducibility and experimental tractability. However, the marine realm, especially bivalves, which are crucial for ecosystem functioning and aquaculture, lacks gnotobiotic models. In this study, we present a method for generating microbiome-depleted and gnotobiotic clams (Ruditapes philippinarum), one of the most widely farmed molluscs in the world and a sentinel organism for climate change. This model expands gnotobiotic research into marine invertebrates, thereby enabling investigations into the impact of microbes on such key animal species.

microbiology↗

bioRxiv2023

Gut microbes predominantly act as symbiotic partners rather than raw nutrients

Animals and their gut microbes mutually benefit their health. In this frame, nutrition has a central role by directly affecting both host and microbes fitness and their effects. This makes nutritional symbioses a complex and dynamic tri-system of diet-microbiota-host. Despite recent discoveries on this field, full control over the interplay among these partners is challenging and hinders the resolution of fundamental questions, such as how to parse the gut microbes effect as raw nutrition or as symbiotic partners? To tackle this, we made use of the well-characterized Drosophila melanogaster/Lactiplantibacillus plantarum experimental model of nutritional symbiosis to generate a quantitative framework of gut microbes effect on the host. We show that the beneficial effect of L. plantarum strains primarily results from the active relationship as symbionts rather than raw nutrients, regardless of the bacterial strain. Metabolomic analysis of both active and inactive bacterial cells further demonstrated the crucial role of the production of beneficial bacterial metabolites, such as N-acetylated-amino-acids, as result of active bacterial growth and function. Altogether, our results provide a ranking and quantification of the main bacterial features contributing to sustain animal growth. We demonstrate that viability is the predominant and necessary variable involved in bacteria-mediated benefit, followed by strain-specific properties and the nutritional potential of the bacterial cells as direct energy source. This contributes to elucidate the role of beneficial bacteria and probiotics, creating a broad quantitative framework for host-gut microbiome that can be expanded to other model systems.

microbiology↗

bioRxiv2022

Assessing the influence of the Mediterranean diet on dental calculus microbiome composition: a pilot study

Human oral microbiome harbours hundreds of bacterial species, which, during evolution, assembled in different niches, such as the microbiome of saliva, tongue, hard palate, gingiva and dental plaque. Among these, saliva has been the most studied ecological niche of the oral microbiome. In this frame, scientific research has demonstrated that several factors concur to determine the saliva microbial composition, including diet, systemic diseases and drugs. However, the influence of such variables on other oral niches, such as the dental calculus, a calcified derivative of dental plaque, is still unexplored. During the last decade, dental calculus has become the primary target for evolutionary microbiome studies because of its ability to keep both bacterial DNA and dietary molecules (i.e., proteins and starch). As a consequence, dental calculus is now considered a powerful tool for obtaining information about oral microbiome composition, diet and individual health status in past populations, making it also appealing for clinical research. Here, we provide the first clinical study, to our knowledge, assessing the inter-variability of dental calculus microbiome in 40 patients. Samples were collected during routine dental inspection and analysed through 16S amplicon sequencing. In addition, we investigated the relationship between oral microbiome and host. Specifically, we tested the influence of Mediterranean diet style on the composition and functional pathways of oral bacteria, with the aim to test the dental calculus as a clinical bio-marker for diet impact and health status.

microbiology↗

bioRxiv2021

Beneficial Lactiplantibacillus plantarum promote Drosophila growth by down-regulating the expression of PGRP-SC1

Animals and their commensal bacteria are known to reciprocally influence many traits of their physiology. Specifically, microbes contribute to the maintenance of the immune system homeostasis, improve host digestive processes, and sustain host growth and development. Several studies have reported that such effects result from an intricate network of nutritional, metabolic and immune inputs and partly rely on the capacity of microbes to regulate the hosts transcriptional response. However, these evidences mainly come from comparing the transcriptional response caused by commensal bacteria with that of axenic animals, making it difficult to identify the specific animal genes that are regulated by beneficial microbes. Here, we employ a well-established model of nutritional symbiosis, Drosophila melanogaster associated with Lactiplantibacillus plantarum, to understand the host genetic pathways regulated by beneficial bacteria and leading to improved host growth and development. Using isogenic L. plantarum strains bearing different growth-promoting effects, we show that the microbial benefit to the host relies on the down-regulation of peptidoglycan- recognition proteins. In particular, we report that the lower expression of PGRP-SC1 exerted by growth-promoting bacteria is responsible for their higher proliferation and the consequent increased production of beneficial metabolites, which ultimately leads to improved host growth and development. Our study helps elucidate the mechanisms underlying the beneficial effect exerted by commensal bacteria, defining the role of PGRP-SC1 in the relationship between Drosophila and its gut microbes. IMPORTANCECommensal bacteria are in constant association with their animal hosts, significantly affecting animal physiology through an intricate network of nutritional, metabolic and immune inputs. Yet, how beneficial bacteria specifically improve animal health is not fully understood. Here, we used a well-established model of nutritional symbiosis to understand how beneficial gut microbes improve host growth via regulation of its transcriptional response. Our study advances the current knowledge in host-microbe interactions by demonstrating that commensal bacteria improve fly growth by actively regulating the expression of immune effectors, which lead to higher immune tolerance. This leads to higher bacterial proliferation and the increased production of beneficial microbial metabolites, which are then consumed by the host. Our results shed light on the complex mechanisms underlying the relationships between a host and its gut microbes.

microbiology↗