Biology subjects

Jones, K. R.

Publications and source records attributed to Jones, K. R..

5 recordsLinked to original sources

bioRxiv2026

Tailocin as an alternative weapon to type VI secretion system in bee gut symbionts

Antagonistic interactions often shape microbial communities, as co-residents compete for resources. One system of interbacterial antagonism involves tailocins: phage tail-like particles produced by some bacteria to kill close relatives. Their roles in natural communities are poorly studied. Here, we identified putative tailocin loci ubiquitously present in genomes of Snodgrassella species, core members of the bee gut microbiota. We purified tailocins from culture supernatants of different Snodgrassella strains and found that these inhibited growth of multiple Snodgrassella strains but not of strains of other species that cooccur in bee guts. Proteomic analyses corroborated the production of tailocins, and cryogenic electron microscopy imaging revealed their morphology and killing activity via membrane disruption. We generated single- and double-gene knockout mutants of a predator Snodgrassella strain that naturally possesses both tailocin and a type VI secretion system (T6SS) that was previously shown to function in intraspecies competition in bee guts. These mutants were used in tests for antagonism against a prey Snodgrassella strain in vivo. Co-inoculations within gnotobiotic honeybees including visualization within guts showed that both tailocin and T6SS are important for Snodgrassella in intraspecies competition. Each of these two antagonism mechanisms inhibits the establishment of susceptible strains within the ileum. Outcomes depend on the timing of colonization by competing strains, with both tailocin and T6SS giving a stronger advantage when the producing strain colonizes first. Thus, tailocin production can underlie priority effects that have been widely observed in the bee gut community and other host-associated bacterial communities.

microbiology↗

bioRxiv2025

Effects of priority on strain-level composition of the honey bee gut community

Host-associated microbiomes are complex communities shaped by interactions between members. The Type VI Secretion System (T6SS), among other bacterial weapons, allows gram-negative bacteria to deliver toxic effectors into competitors. In this study, we investigated the impact of differential colonization timing on the competitive advantage associated with T6SS possession using Snodgrassella alvi, a core symbiont of the honey bee gut microbiome. Following a timeline based on the natural establishment window of the gut microbiome, we sequentially inoculated newly emerged bees with fluorescently labeled strains that differed in presence of the T6SS-1. When inoculated simultaneously, the T6SS-1-possessing strain (wkB2) consistently excluded the T6SS-1-lacking strain (wkB332); however, when given a five-day advantage, the second strain was consistently excluded regardless of strain identities. With a one-day advantage, the effect of priority was weakened, but wkB332 was able to persist following introduction of wkB2. Utilizing a wkB2 T6SS-1 knockout strain, we repeated our 24-hour priority experiments and found that the T6SS-1 contributes to invasion outcomes along with other mechanisms of competition. Through fluorescent microscopy, we explored how coexisting strains in these experimental scenarios organize spatially within the bee ileum. Our results demonstrate that colonization timing can have lasting consequences for strain composition of the established microbiome. These findings illustrate the influence of stochastic processes in microbial community assembly and emphasize that differences in colonization timing may alter competitive outcomes between taxa, impacting taxon coexistence. ImportanceThe bacterial gut communities of honey bees possess considerable strain-level diversity between hives, between individual bees and within individual bees. However, the factors underlying strain coexistence are unclear. Here, we provide support for timing of colonization, or priority effects, as one factor driving this strain level diversity. Our results show that priority inoculation can prevent colonization by subsequent competing bacterial strains and mitigate advantages conferred through bacterial weaponry. Further, a brief window of priority can facilitate the coexistence of strongly and weakly competitive strains within single bees. These results add to our understanding of the impacts of priority effects in host-associated microbial communities and provide support for the development of future probiotic strategies aimed directing microbiome structure to benefit honey bee health.

ecology↗

bioRxiv2020

Only 40% of the world's forests are in good health

Many global environmental agendas, including halting biodiversity loss, reversing land degradation, and limiting climate change, depend upon retaining forests with high ecological integrity, yet the scale and degree of forest modification remains poorly quantified and mapped. By integrating data on observed and inferred human pressures and an index of lost connectivity, we generate the first globally-consistent, continuous index of forest condition as determined by degree of anthropogenic modification. Globally, only 17.4 million km2 of forest (40.5%) have high landscape level integrity (mostly found in Canada, Russia, the Amazon, Central Africa and New Guinea) and only 27% of this area is found in nationally-designated protected areas. Of the forest in protected areas, only 56% has high landscape level integrity. Ambitious policies that prioritize the retention of forest integrity, especially in the most intact areas, are now urgently needed alongside current efforts aimed at halting deforestation and restoring the integrity of forests globally.

ecology↗

bioRxiv2019

Conservation attention necessary across at least 44% of Earth’s terrestrial area to safeguard biodiversity

More ambitious conservation efforts are needed to stop the global biodiversity crisis. Here, we estimate the minimum land area to secure important sites for terrestrial fauna, ecologically intact areas, and the optimal locations for representation of species ranges and ecoregions. We discover that at least 64 million km2 (44% of terrestrial area) requires conservation attention. Over 1.8 billion people live on these lands so responses that promote agency, self-determination, equity, and sustainable management for safeguarding biodiversity are essential. Spatially explicit land-use scenarios suggest that 1.3 million km2 of land requiring conservation could be lost to intensive human land-uses by 2030, which requires immediate attention. However, there is a seven-fold difference between the amount of habitat converted under optimistic and pessimistic scenarios, highlighting an opportunity to avert this crisis. Appropriate targets in the post-2020 Global Biodiversity Framework to ensure conservation of the identified land would contribute substantially to safeguarding biodiversity.

ecology↗

bioRxiv2019

Area requirements to safeguard Earth’s marine species

Despite global policy commitments to preserve Earths marine biodiversity, many species are in a state of decline. Using data on 22,885 marine species, we identify 8.5 million km2 of priority areas that complement existing areas of conservation and biodiversity importance. New conservation priorities are found in over half (56%) of all coastal nations, with key priority regions in the northwest Pacific Ocean and Atlantic Ocean. We identify where different conservation actions, ranging from marine protected areas to broader policy approaches, may best overcome anthropogenic threats to these areas. This analysis shows 26-41% of the ocean (depending on targets used for species representation) needs to be effectively conserved through a combination of site-based actions and wider policy responses to achieve global conservation and sustainable development agendas.\n\nOne Sentence SummaryAt least 26% of the ocean needs a combination of site-based conservation and wider policy responses to achieve global conservation goals.

ecology↗