Biology subjects

Prentice, J. A.

Publications and source records attributed to Prentice, J. A..

6 recordsLinked to original sources

bioRxiv2026

A branching cell-fate decision in biofilm dispersal enables long-term surface persistence

Biofilms are the most ancient multicellular communities on Earth, representing a primitive developmental system that protects microbes from threats. Biofilm dispersal, whereby bacteria exit biofilms, is critical for the spread of pathogens to new infection sites. Here, using Vibrio cholerae, we show that dispersal events are accompanied by a branching cell-fate decision. While [~]90% of cells disperse, a viable subpopulation remains within a residual matrix. This post-dispersal biofilm community (PDBC) is established by the matrix protein RbmA and adopts a specialized anabolic program that enhances tolerance to antibiotics and bacteriophages. Our findings reveal that PDBCs act as a resilient "seed-bank" capable of rapidly re-populating the niche without requiring de novo matrix biosynthesis, providing a mechanistic basis for the recurrence and spread of chronic infections.

microbiology↗

bioRxiv2025

Label-free microscopy enables high-throughput identification of genes controlling biofilm development

The biofilm mode of growth plays a critical role in microbial ecology and in the persistence of human pathogens. Yet, much remains unknown regarding the molecular determinants of biofilms in human pathogens. In this study, we present label-free analysis of biofilms (LFAB), an imaging approach that combines time-lapse, low-magnification brightfield microscopy with regional optical density measurements to quantify biofilm biomass. Unlike other approaches to biofilm biomass quantification, LFAB enables real-time, non-perturbative, and high-throughput monitoring of biofilms. We validated LFAB in diverse microbes and found that our measurements strongly correlate with traditional biofilm assays. We then used LFAB to identify and characterize critical factors mediating biofilm formation in Streptococcus pneumoniae, a major human pathogen whose biofilm lifecycle is known to be intimately related to colonization and infection. Initial characterization revealed that S. pneumoniae microcolonies form by radial expansion of attached cells, displaying reproducible morphology and growth dynamics. Screening of a transposon mutant library revealed that genes spanning carbohydrate metabolism, signaling, surface binding, cell wall synthesis, and adhesion impinge on the biofilm lifecycle of S. pneumoniae. We performed follow-up investigations of choline binding protein A (CbpA) and its adjacently encoded two-component system regulator, which we find are critical for the dynamics of microcolony biofilms in S. pneumoniae. Overall, this work establishes LFAB as a powerful approach for identifying and characterizing biofilm determinants across bacteria and uncovers key regulators of the biofilm lifecycle in a major human pathogen.

microbiology↗

bioRxiv2024

Biofilm dispersal patterns revealed using far-red fluorogenic probes

Bacteria frequently colonize niches by forming multicellular communities called biofilms. To explore new territories, cells exit biofilms through an active process called dispersal. Biofilm dispersal is essential for bacteria to spread between infection sites, yet how the process is executed at the single-cell level remains mysterious. Here, we characterize dispersal at unprecedented resolution for the global pathogen Vibrio cholerae. To do so, we first developed a far-red cell-labeling strategy that overcomes pitfalls of fluorescent protein-based approaches. We reveal that dispersal initiates at the biofilm periphery and [~]25% of cells never disperse. We define novel micro-scale patterns that occur during dispersal, including biofilm compression and the formation of dynamic channels. These patterns are attenuated in mutants that reduce overall dispersal or that increase dispersal at the cost of homogenizing local mechanical properties. Collectively, our findings provide fundamental insights into the mechanisms of biofilm dispersal, advancing our understanding of how pathogens disseminate.

microbiology↗

bioRxiv2023

Pneumococcal Extracellular Vesicles Mediate Horizontal Gene Transfer via the Transformation Machinery

Bacterial cells secrete extracellular vesicles (EVs), the function of which is a matter of intense investigation. Here, we show that the EVs secreted by the human pathogen Streptococcus pneumoniae (pneumococcus) are associated with bacterial DNA on their surface and can deliver this DNA to the transformation machinery of competent cells. These findings suggest that EVs contribute to gene transfer in Gram-positive bacteria, and in doing so, may promote the spread of drug resistance genes in the population. SignificanceThis work extends our understanding of horizontal gene transfer and the roles of extracellular vesicles in pneumococcus. This bacterium serves as the model for transformation, a process by which bacteria can take up naked DNA from the environment. Here we show that extracellular vesicles secreted by the pneumococcus have DNA on their surface, and that this DNA can be imported by the transformation machinery facilitating gene transfer. Understanding EV-mediated gene transfer may provide new avenues to manage the spread of antibiotic drug resistance.

microbiology↗

bioRxiv2022

Synergy between c-di-GMP and quorum-sensing signaling in Vibrio cholerae biofilm morphogenesis

Transitions between individual and communal lifestyles allow bacteria to adapt to changing environments. Bacteria must integrate information encoded in multiple sensory cues to appropriately undertake these transitions. Here, we investigate how two prevalent sensory inputs converge on biofilm morphogenesis: quorum sensing, which endows bacteria with the ability to communicate and coordinate group behaviors, and second messenger c-di-GMP signaling, which allows bacteria to detect and respond to environmental stimuli. We use Vibrio cholerae as our model system, the autoinducer AI-2 to modulate quorum sensing, and the polyamine norspermidine to modulate NspS-MbaA-mediated c-di-GMP production. Individually, AI-2 and norspermidine drive opposing biofilm phenotypes, with AI-2 repressing and norspermidine inducing biofilm formation. Surprisingly, however, when AI-2 and norspermidine are simultaneously detected, they act synergistically to elevate biofilm formation. We show that this effect is caused by quorum-sensing-mediated activation of nspS-mbaA expression, which increases the levels of NspS and MbaA, and in turn, c-di-GMP biosynthesis, in response to norspermidine. Increased MbaA-synthesized c-di-GMP activates the VpsR transcription factor, driving elevated expression of genes encoding key biofilm matrix components. Thus, in the context of biofilm formation in V. cholerae, quorum-sensing regulation of c-di-GMP-metabolizing receptor levels connects changes in cell population density to detection of environmental stimuli. ImportanceThe development of multicellular communities, known as biofilms, facilitates beneficial functions of gut microbiome bacteria and makes bacterial pathogens recalcitrant to treatment. Understanding how bacteria regulate the biofilm lifecycle is fundamental to biofilm control in industrial processes and in medicine. Here, we demonstrate how two major sensory inputs - quorum-sensing communication and second messenger c-di-GMP signaling - jointly regulate biofilm morphogenesis in the global pathogen Vibrio cholerae. We characterize the mechanism underlying a surprising synergy between quorum-sensing and c-di-GMP signaling in controlling biofilm development. Thus, the work connects changes in cell population density to detection of environmental stimuli in a pathogen of clinical significance.

microbiology↗

bioRxiv2021

Quantitative input-output dynamics of a c-di-GMP signal-transduction cascade in Vibrio cholerae

Bacterial biofilms are multicellular communities that collectively overcome environmental threats and clinical treatments. To regulate the biofilm lifecycle, bacteria commonly transduce sensory information via the second-messenger molecule cyclic diguanylate (c-di-GMP). Using experimental and modeling approaches, we quantitatively capture c-di-GMP signal transmission via the bifunctional polyamine receptor NspS-MbaA, from ligand binding to output, in the pathogen Vibrio cholerae. Upon binding of norspermidine or spermidine, NspS-MbaA synthesizes or degrades c-di-GMP, respectively, which in turn, drives alterations specifically to biofilm gene expression. A longstanding question is how output specificity is achieved via c-di-GMP, a diffusible molecule that regulates dozens of effectors. We show that NspS-MbaA signals locally to specific effectors, sensitizing V. cholerae to polyamines. However, local signaling is not required for specificity, as changes to global cytoplasmic c-di-GMP levels can selectively regulate biofilm genes. This work establishes the input-output dynamics underlying c-di-GMP signaling, which could be useful for developing bacterial manipulation strategies.

microbiology↗