Biology subjects

Moore, M. L.

Publications and source records attributed to Moore, M. L..

7 recordsLinked to original sources

bioRxiv2026

Intranasal immunization with live-attenuated RSV-vectored SARS-CoV-2 vaccines elicits antigen-specific systemic and mucosal immunity and protects against viral challenge and natural infection

The emergence of new SARS-CoV-2 variants and breakthrough infections underscores the need for next-generation vaccines capable of protecting from natural infection and/or preventing virus transmission to others. Intranasal vaccination offers a promising approach by eliciting local immune responses in the nasal mucosa, the primary site of infection and reservoir for transmissible virus. We evaluated two live-attenuated, respiratory syncytial virus vectored vaccines in which the RSV F and G surface glycoproteins were replaced with a chimeric SARS-CoV-2 Spike protein from either the ancestral USA/WA-1/2020 strain (MV-014-212) or the Delta variant (MV-014-212-delta). A single intranasal dose of either vaccine elicited systemic and mucosal immunity in K18-hACE2 mice, including serum neutralizing antibodies, Spike-specific memory B cells and plasmablasts, and Spike-specific CD8 lung-resident memory T cells. Although MV-014-212-delta vaccination provided the best protection against Delta variant virus challenge, both vaccines decreased viral loads in nasal discharge, lung and brain, and reduced weight loss and mortality. In naturally acquired infection studies, vaccinated hamsters exposed to infected cagemates exhibited minimal weight loss, limited viral replication within the nasal mucosa, and attenuated lung pathology. Therefore, intranasal RSV-vectored vaccines can elicit broad protective respiratory immunity, suggesting that this platform could be leveraged for other respiratory pathogens.

immunology↗

bioRxiv2025

Domoic acid biosynthesis and genome expansion in Nitzschia navis-varingica

Production of the neurotoxin domoic acid (DA) by benthic diatom Nitzschia navis-varingica poses considerable health and economic concerns. In this study, we employed whole genome sequencing and transcriptomic analyses of regionally distinct N. navis-varingica strains to unravel the genomic underpinnings of DA biosynthesis. Our analyses revealed sizable genomes--characterized by an abundance of repetitive elements and noncoding DNA--that exceed the size of any other pennate diatoms. Central to our findings is the discovery of an expanded domoic acid biosynthesis (dab) gene cluster, spanning over 60 kb and marked by a unique organization that includes core genes interspersed with additional genetic elements. Phylogenetic and syntenic comparisons indicate that transposition events may have driven the expansion and reorganization of this cluster. Biochemical assays validated that the kainoid synthase encoded by dabC catalyzes the formation of isodomoic acid B, thereby establishing a distinct chemotype in contrast to the DA profiles of planktonic diatoms. These results highlight the evolutionary trajectory of DA biosynthesis in diatoms and potential advantages conferred by genome expansion and enzyme diversification in dynamic marine environments. IMPORTANCEDomoic acid (DA) is a potent neurotoxin produced by marine micro- and macroalgae problematic to fisheries and toxic to humans and animals. Our study elucidates the molecular mechanisms underlying DA production in the widespread Western Pacific benthic diatom, Nitzschia navis-varingica. Genomic and biochemical insights add information to our understanding of the evolution of toxin production across diverse phyla and also fill a gap in the knowledge of secondary metabolism in marine diatoms. These findings provide a genetic framework for identifying toxin production and its impacts in the benthos of vulnerable, coastal ecosystems.

genomics↗

bioRxiv2023

Arbuscular mycorrhiza convey significant plant carbon to a diverse hyphosphere microbial food web and mineral-associated organic matter

O_LIArbuscular mycorrhizal fungi (AMF) transport substantial plant carbon (C) that serves as a substrate for other soil organisms, a precursor of soil organic matter (SOM), and a driver of soil microbial dynamics. Using two-chamber microcosms where an air gap isolated AMF from roots, we 13CO2-labeled Avena barbata for six weeks and measured. the C Rhizophagus intraradices transferred to SOM and hyphosphere microorganisms. C_LIO_LINanoSIMS imaging, IRMS, 13C NMR, and SOM density fractionation showed hyphae and roots had similar 13C enrichment. AMF transferred 0.77 mg C per g of soil (increasing total C by 2%); 33% was found in occluded or mineral-associated pools, primarily as carbohydrates. C_LIO_LIIn the AMF hyphosphere, there was no overall change in community diversity but 36 bacterial ASVs significantly changed in relative abundance. With stable isotope probing (SIP)-enabled shotgun sequencing, we found taxa from the Solibacterales, Sphingobacteriales, Myxococcales and Nitrososphaerales (ammonium oxidizing archaea) were highly enriched in AMF-imported 13C (>20 atom%). Mapping 13C-enriched metagenome-assembled genomes to total ASVs showed at least 92 bacteria and archaea were significantly 13C-enriched. C_LIO_LIOur results illustrate the quantitative impact of hyphal C transport on the formation of potentially protective SOM pools and indicate microbial roles in the AMF hyphosphere soil food web. C_LI

microbiology↗

bioRxiv2023

Genome-wide CRISPRi knockdown to map gene essentiality landscape in coliphages {lambda} and P1

Phages are one of the key ecological drivers of microbial community dynamics, function and evolution. Despite their importance in bacterial ecology and evolutionary processes, phage genes are poorly characterized, hampering their usage in a variety of biotechnological applications. Methods to characterize such genes, even those critical to the phage life cycle, are labor-intensive and are generally phage-specific. Here, we develop a systematic gene essentiality mapping method scalable to new phage-host combinations that facilitate the identification of non-essential genes. As proof of concept, we use a catalytically inactive Cas12a mediated genome-wide CRISPRi assay to determine the essential genes in the canonical coliphages {lambda} and P1. Results from a single panel of CRISPRi probes largely recapitulate the essential gene roster determined from decades of genetic analysis for lambda and provide new insights into essential and nonessential loci in P1. We present evidence of how CRISPRi polarity can lead to false positive gene essentiality assignments and recommend caution towards interpreting CRISPRi data on gene essentiality when applied to less studied phages. Finally, we show that we can engineer phages by inserting DNA barcodes into newly identified inessential regions, which will empower processes of identification, quantification and tracking of phages in diverse applications.

microbiology↗

bioRxiv2023

Geochemical constraints on bacteriophage infectivity in terrestrial environments

Lytic phages can be potent and selective inhibitors of microbial growth and can have profound impacts on microbiome composition and function. However, there is uncertainty about the biogeochemical conditions under which phage predation can proceed and modulate microbial ecosystem function, particularly in terrestrial systems. Ionic strength is known to be critical for infection of bacteria by many phages, but there is limited quantitative data on ion thresholds for phage infection that can be compared with environmental ion concentrations. Similarly, while carbon composition varies in terrestrial environments, we know little of which carbon sources favor or disfavor phage infection and how these higher order interactions impact microbiome function. Here, we measured the half-maximal effective concentrations (EC50) of 80 different inorganic ions for the infection of E. coli with two canonical dsDNA and ssRNA phages, T4 and MS2, respectively. We found that many alkaline earth metals and alkali metals enabled successful lytic infection but that the ionic strength thresholds varied for different ions between phages. Additionally, using a freshwater nitrate reducing microbiome, we found that the ability of lytic phage to influence nitrate reduction end-products was dependent on the carbon source as well as the ion concentration. For all phage:host pairs we tested, the ion EC50s for phage infection we measured exceed the ion concentrations found in many terrestrial freshwater systems. Thus, our findings support a model where the influence of phages on terrestrial microbial functional ecology is greatest in hot spots and hot moments such as metazoan guts, drought influenced soils, or biofilms where ion concentration is locally or transiently elevated and carbon source composition is of a sufficiently low complexity to enrich for a dominant phage susceptible population. SignificanceViral-prokaryote dynamics greatly influence microbial ecology and the earths biogeochemical cycles. Thus, identifying the key environmental controls on phage predation is critical for predictive microbial ecology. Here we conduct laboratory experiments that implicate ionic strength and carbon composition as major controls on phage interactions with bacterial hosts in terrestrial microbiomes. We propose a model in which terrestrial phage predation is most favored in drought impacted soils and in higher ionic strength environments such as metazoan guts or between adjacent cells in biofilms.

microbiology↗

bioRxiv2023

Generating high quality reference genomes from field collected specimens by optimizing preservation

Sample preservation challenges efforts to generate high-quality reference genomes or pangenomes for all 2 million+ plant and animal species. Here we show 95% ethanol protects against degradation for fish blood (22{degrees}C, [≤]6 weeks) and plant tissue (4{degrees}C, [≤]3 weeks). Using Nanopore, we assemble high quality reference genomes from three fish and two plant species (contig N50: 6.5-13.8Mb; BUSCO completeness: 94.4-99.2%; QV: 43.8 for M. esculenta).

genomics↗

bioRxiv2021

One mucosal administration of a live attenuated recombinant COVID-19 vaccine protects non-human primates from SARS-CoV-2

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the causative agent of the COVID-19 global pandemic. SARS-CoV-2 is an enveloped RNA virus that relies on its trimeric surface glycoprotein, spike, for entry into host cells. Here we describe the COVID-19 vaccine candidate MV-014-212, a live attenuated, recombinant human respiratory syncytial virus (RSV) expressing a chimeric SARS-CoV-2 spike as the only viral envelope protein. MV-014-212 was attenuated and immunogenic in African green monkeys (AGMs). One mucosal administration of MV-014-212 in AGMs protected against SARS-CoV-2 challenge, reducing by more than 200- fold the peak shedding of SARS-CoV-2 in the nose. MV-014-212 elicited mucosal immunity in the nose and neutralizing antibodies in serum that exhibited cross-neutralization against two virus variants of concern. Intranasally delivered, live attenuated vaccines such as MV-014-212 entail low-cost manufacturing suitable for global deployment. MV-014-212 is currently in phase 1 clinical trials as a single-dose intranasal COVID-19 vaccine.

immunology↗