Biology subjects

Bonilla-Rosso, G.

Publications and source records attributed to Bonilla-Rosso, G..

6 recordsLinked to original sources

bioRxiv2026

Species boundaries structure competitive interactions among honeybee gut bacteria

Bacterial species often harbor extensive strain-level diversity, raising the question of whether strains, rather than species, are the relevant ecological units. We quantified pairwise interactions among 12 strains from four prevalent Lactobacillus species of the honeybee gut microbiota using gnotobiotic bees. Microbiota-depleted bees were colonized with individual strains and all 66 pairwise combinations, with strain abundances measured by colony counts and strain-resolved amplicon sequencing. Negative interactions predominated, with most significant interactions involving mutual inhibition. Within-species interactions were stronger and more asymmetric than between-species interactions, producing less even community compositions. Across repeated cycles of colonization in microbiota-depleted bees, three of four within-species pairs lost one strain, whereas all four between-species pairs persisted. These results indicate that closely related strains experience greater niche overlap and stronger competition than strains from different species, supporting bacterial species as ecologically differentiated units while highlighting the importance of strain-specific traits in shaping community assembly and stability.

microbiology↗

bioRxiv2025

Strain-level and phenotypic stability contrasts with plasmid and phage variability in water kefir communities

Microbial communities can change in response to top-down factors, such as phages, and bottom-up factors, such as nutrient availability. Previous studies have successfully investigated bacterial species-level dynamics, but diversity and interactions beyond the species-level is usually lacking. Traditional fermented foods, such as water kefir, provide ideal systems to study ecological and evolutionary dynamics beyond the species-level, as they are simple and trackable systems that are cultivated in non-sterile, nutrient-rich environments which foster microbial growth and invasion. Despite the central role of only a few lactic acid bacteria for fermentation, little is known about the genomic diversity and dynamics of these community members over time. Within the framework of a graduate course, 35 students propagated water kefir across several generations under different nutrient conditions and in different households to study microbial responses over time. We found that water kefir communities were generally stable at the species-level, with only rare bacterial species replaced over long timescales (more than 2 years). While we observed little strain-level diversity with few strain replacements over long timescales, closely related strains exhibited variation in accessory gene content, often encoded on plasmids, particularly those involved in ecologically meaningful functions such as sugar utilization pathways and phage defense systems. We hypothesise that these genomic variations could reflect the adaptations of strains to different sugars and phages. Consistent with this, we observed a diverse array of phages, many likely originating from the unique household environments. By documenting the genomic landscape of microbial species, strains, plasmids, and phages, this study advances our understanding of the diversity and dynamics of microbial communities in fermented foods. Furthermore, our course material is publicly available and offers a blueprint for bridging the gap between teaching and research, inspiring the next generation of scientists to unravel the complexities of microbial ecosystems. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=137 SRC="FIGDIR/small/640646v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@56db6borg.highwire.dtl.DTLVardef@5f6dc6org.highwire.dtl.DTLVardef@11fff14org.highwire.dtl.DTLVardef@1a37a9f_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2023

Comparative genomic analysis reveals novel phylogenetically intermediate Streptococci with high phenotypic diversity in the human distal lung microbiota.

Streptococci are one of the predominant and the most diverse genus in the human lung. Previously, we isolated human distal lung Streptococci from bronchoalvolear lavage fluid (BALF) as part of the human Lung Microbiota culture Collection (LuMiCol). Here, we performed whole genome sequencing, comparative phylogenomics and phenotypic characterization of six Streptococcal isolates representing the phylogenetic diversity of the genus in distal human lung. Here, we report five new species and one new subspecies including phylogenetic intermediates of commonly found Streptococci not limited to human lung. Pangenome analysis reveals gene content, evolutionary relationships, and metabolic functions shedding light on contribution of these Streptococci to lung microbial metabolism. Antimicrobial resistance gene analysis followed by MIC determination revealed macrolide, lincosamide and tetracycline resistance in lung Streptococci. We show the presence of capsular genes in lung streptococci both matching to the prototypical capsular genes (cps) and unique genes. Interestingly, the new Streptococcus isolate sp. nov. P2E5, genetically identical to the most prevalent Streptococcus in the human distal lung was revealed to be a phylogenetic intermediate between the S. mitis group and S. pneumoniae. It also harbors the pneumolysin (ply) gene and was found to have the serotype 21E. Finally, core genome phylogeny reveals that lung Streptococci the are evolutionary distinct from oral Streptococcal isolates in expanded Human Oral Microbiome Database (eHOMD). Hence, these findings we reveal new phylogenetically distinct Streptococcal species from the human distal lung microbiota and its genetic diversity and metabolism to understand the microbial ecology of human lung. ImportanceA healthy human distal lung harbour characteristic microbial communities mostly composed of oropharyngeal taxa, which are facultative or obligative anaerobes despite lung being the medium of oxygen intake. However, little is known about the genetic and functional diversity of these bacteria owing to the lack of resources including availability of primary lung isolate from human samples. Therefore, we have established a large bacterial collection that covers all major phyla by cultivating human bronchoalveolar lavage fluid (BALF) under various conditions. Streptococcus is the most prevalent and diverse genera in the human lung microbiota. Using genetic and biochemical approaches, we studied six diverse lung isolates from our collection representing the actual Streptococcal diversity and identify these as new species and subspecies. We hypothesize that learning about the phylogenetic genetic diversity, preferred metabolism and molecular structures of these Streptococci will provide with new insights on the understudied microbial ecosystem of the human lung.

microbiology↗

bioRxiv2020

A prevalent and culturable microbiota links ecological balance to clinical stability of the human lung after transplantation

There is accumulating evidence that the lower airway microbiota impacts lung health. However, the link between microbial community composition and lung homeostasis remains elusive. We combined amplicon sequencing and culturomics to characterize the viable bacterial community in 234 longitudinal bronchoalveolar lavage samples from 64 lung transplant recipients and established links to viral loads, host gene expression, lung function, and transplant health. We find that the lung microbiota post-transplant can be categorized into four distinct compositional states, pneumotypes. The predominant balanced pneumotype was characterized by a diverse bacterial community with moderate viral loads, and host gene expression profiles suggesting immune tolerance. The other three pneumotypes were characterized by being either microbiota-depleted, or dominated by potential pathogens, and were linked to increased immune activity, lower respiratory function, and increased risks of infection and rejection. Collectively, our findings establish a link between the lung microbial ecosytem, human lung function, and clinical stability post-transplant. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=191 SRC="FIGDIR/small/106211v1_ufig1.gif" ALT="Figure 1"> View larger version (57K): org.highwire.dtl.DTLVardef@1df2be3org.highwire.dtl.DTLVardef@ba839dorg.highwire.dtl.DTLVardef@116f657org.highwire.dtl.DTLVardef@86d8ac_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2019

Acetobacteraceae in the honey bee gut comprise two distant clades with diverging metabolism and ecological niches

Various bacteria of the family Acetobacteraceae are associated with the gut environment of insects. Honey bees harbor two distinct Acetobacteraceae in their gut, Alpha2.1 and Alpha2.2. While Alpha2.1 seems to be a gut specialist, Alpha2.2 is also found in the diet (e.g. royal jelly), the hypopharyngeal glands, and the larvae of honey bees. Here, we combined amplicon and genome sequencing to better understand functional differences associated with the ecology of Alpha2.1 and Alpha2.2. We find that the two phylotypes are differentially distributed along the worker and queen bee gut. Phylogenetic analysis shows that Alpha2.2 is nested within the acetic acid bacteria and consists of two separate sub-lineages, whereas Alpha2.1 belongs to a basal lineage with an unusual GC content for Acetobacteraceae. Gene content analysis revealed major differences in the central carbon and respiratory metabolism between the two phylotypes. While Alpha2.2 encodes two periplasmic dehydrogenases to carry out oxidative fermentation, Alpha2.1 lacks this capability, but instead harbors a diverse set of cytoplasmic dehydrogenases. These differences are accompanied by the loss of the TCA cycle in Alpha2.2, but not in Alpha2.1. We speculate that Alpha2.2 has specialized for fast-resource utilization through incomplete carbohydrate oxidation, giving it an advantage in sugar-rich environments such as royal jelly. On the contrary, the broader metabolic range of Alpha2.1 may provide an advantage in the worker bee hindgut, where competition with other bacteria and flexibility in resource utilization may be relevant for persistence. Our results show that bacteria belonging to the same family may utilize vastly different strategies to colonize niches associated with the animal gut.

genomics↗

bioRxiv2018

Genomic changes underlying host specialization in the bee gut symbiont Lactobacillus Firm5

Bacteria that engage in longstanding associations with particular hosts are expected to evolve host-specific adaptations that limit their capacity to thrive in other environments. Consistent with this, many gut symbionts seem to have a limited host range, based on community profiling and phylogenomics. However, few studies have experimentally investigated host specialization of gut symbionts and underlying mechanisms have largely remained elusive. Here, we studied host specialization of a dominant gut symbiont of social bees, Lactobacillus Firm5. We show that Firm5 strains isolated from honey bees and bumble bees separate into deep-branching phylogenetic lineages. Despite their divergent evolution, colonization experiments show that bumble bee strains are capable of colonizing the honey bee gut. However, they were less successful than honey bee strains, and competition with honey bee strains completely abolished their colonization, whereas honey bee strains were able to coexist. This suggests that both host selection and interbacterial competition play important roles for host specialization. Using comparative genomics of 27 Firm5 isolates, we identified candidate genomic changes underlying host specialization. We found that honey bee strains harbored a larger and more diverse gene pool of carbohydrate-related functions than bumble bee strains. As dietary-derived carbohydrates are the main energy source for strains of the Firm5 phylotype, the metabolic flexibility of honey bee strains may give these bacteria a competitive advantage over bumble bee strains in colonizing the gut niche and hence contribute to host specialization.

microbiology↗