Biology subjects

Allen, M. L.

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

4 recordsLinked to original sources

bioRxiv2026

Listianol, a Carotenoid Biosynthesis Inhibitor from a Methylotrophic Bacterium, Alters the Composition of a Phyllosphere Microbial Community

The microbial communities that inhabit the phyllosphere, the above-ground portion of plants, are important for plant growth and resilience. However, the natural products that mediate interactions among these organisms and with their environment remain understudied, limiting our molecular-level understanding of how phyllosphere microbial communities are structured and maintained. Natural product-mediated microbial competition is typically associated with growth inhibition, but may also occur through other mechanisms in these communities. Many bacteria produce pigments to mitigate oxidative stress, and here we identify listianol, a previously undescribed natural product that inhibits the pigmentation of diverse bacteria. Listianol blocks carotenoid biosynthesis by targeting the desaturases CrtN and CrtI. This activity sensitizes normally pigmented bacteria to UVB radiation in vitro, and a listianol-producing strain reshapes the composition of a model bacterial community on Arabidopsis thaliana under UVB exposure. Together, these findings identify pigmentation inhibition as a potential form of competition in the phyllosphere.

microbiology↗

bioRxiv2020

Ever-increasing viral diversity associated with the red imported fire ant Solenopsis invicta (Formicidae: Hymenoptera)

BackgroundAdvances in sequencing and analysis tools have facilitated discovery of many new viruses from invertebrates, including ants. Solenopsis invicta is an invasive ant that has quickly spread around world causing significant ecological and economic impacts. Its virome has begun to be characterized pertaining to potential use of viruses as natural enemies. Although the S. invicta virome is best characterized among ants, most studies have been performed in its native range, with little information from invaded areas. MethodsUsing a metatranscriptome approach, we further characterized viruses associated with S. invicta, in two introduced areas, U.S and Taiwan. The data set used here was obtained from different stages (larvae, pupa, and adults) of S. invicta life cycle. Publicly available RNA sequences from GenBanks Sequence Read Archive were downloaded and de novo assembled using CLC Genomics Workbench 20.0.1. Contigs were compared against the non-redundant protein sequences and those showing similarity to viral sequences were further analyzed. ResultsWe characterized five putative new viruses associated with S. invicta transcriptomes. Sequence comparisons revealed extensive divergence across ORFs and genomic regions with most of them sharing less than 40% amino acid identity with those closest homologous sequences previously characterized. The first negative-sense single-stranded RNA viruses included in the orders Bunyavirales and Mononegavirales are reported. In addition, two positive single-strand viruses and one single strand DNA virus were also characterized. While the presence of a putative tenuivirus associated with S. invicta was previously suggested to be a contamination, here we characterized and present strong evidence that Solenopsis invicta virus 14 (SINV-14) is a tenui-like virus that has a long-term association with the ant. Furthermore, based on virus abundance compared to housekeeping genes, phylogenetic relationships, and completeness of viral coding sequences, our results suggest that four of five viruses reported, those being SINV-14, SINV-15, SINV-16 and SINV-17, replicate in the ant S. invicta. ConclusionsThe present study expands our knowledge about viral diversity associated with S. invicta in introduced areas with potential to be used as biological control agents, which will require further biological characterization.

microbiology↗

bioRxiv2020

Estimating bobcat (Lynx rufus) abundance in Wisconsin during 1981-2015

Quantifying and estimating trends in wildlife abundance is critical for their management and conservation. Harvest-based indices are often used as a surrogate index for wildlife population. Sex-Age-Kill (SAK) models generally use the age-at-harvest of males and females, combined with annual mortality and reproduction rates to calculate a preharvest population estimate. We used and SAK model to estimate abundance for bobcats from 1981-2015. Pre-hunt population size ranged from approximately 1630-2148 during 1981-1995 after which the population increased to a maximum of 4439 in 2005 before declining to 2598 in 2013. Pre-hunt population size was highly correlated an index of abundance from winter track counts (r = 0.93). We found that the model, as currently implemented by WNDR, appears to provide an accurate trend of statewide bobcat abundance. SAK models more logistically feasible for long-term evaluations of population trends overbroad spatial extents than more intensive methods. While SAK models may be the only technique available to wildlife managers for estimating the abundance of harvested species, we encourage additional research to evaluate the effects of potential biases on estimates of abundance.

ecology↗

bioRxiv2020

Mesopredators display behaviourally plastic responses to dominant competitors when scavenging and communicating

Mesopredators face interspecific competition and intraguild predation when sharing resources with apex predators or more dominant mesopredators. We theorize that mesopredators use a variety of tactics to avoid competitively dominant predators at shared locations, such as scavenging and communication sites, that provide a mix of risks and rewards to these smaller predators. We examined whether mesopredator species employed behavioural tactics to reduce risks from dominant pumas when exploiting resources. We monitored carcasses in the Santa Cruz Mountains, CA across a gradient of human development and treated half of the carcasses with puma sign. Bobcats visited treated carcasses significantly later and for less time. Contrary to our expectations, coyotes and grey foxes were more likely to visit treated carcasses, although foxes were significantly less likely to visit a carcass also used by coyotes. Bobcats and foxes were less likely to visit carcasses at higher development levels whereas raccoons exhibited the opposite pattern. At communication sites, we observed temporal segregation among mesopredators and pumas. Coyotes and small predators exhibited the most segregation, followed by coyotes and pumas, and raccoons and pumas. Our results suggest subordinate predators employ a combination of spatial and temporal avoidance to minimize competitive interactions at shared sites.

ecology↗