Biology subjects

Foster, L.

Publications and source records attributed to Foster, L..

23 records · Page 2Linked to original sources

bioRxiv2020

Trade-offs between sperm viability and immune protein expression in honey bee queens (Apis mellifera)

Queens of many social hymenoptera keep sperm alive within their specialized storage organ, the spermatheca, for years, defying the typical trade-off between lifespan and reproduction. However, whether honey bee queens experience a trade-off between reproduction and immunity is unknown, and the biochemical processes underlying sperm viability are poorly understood. Here, we survey quality metrics and viral loads of honey bee queens from nine genetic sources. Queens rated as failed by beekeepers had lower sperm viability, fewer sperm, and higher levels of SBV and BQCV. Quantitative proteomics on N = 123 spermathecal fluid samples shows, after accounting for sperm count, health status, and apiary effects, five spermathecal fluid proteins significantly correlating with sperm viability: odorant binding protein (OBP)14, lysozyme, serpin 88Ea, artichoke, and heat-shock protein (HSP)10. The significant negative correlation of lysozyme--a conserved immune effector--with sperm viability is consistent with a reproduction vs. immunity trade-off in honey bee queens.

molecular biology↗

bioRxiv2020

The parasite Schistocephalus solidus secretes proteins with putative host manipulation functions

BackgroundManipulative parasites are thought to liberate molecules in their external environment acting as manipulation factors with biological functions implicated in their hosts physiological and behavioural alterations. These manipulation factors are part of a complex mixture called the secretome. While the secretomes of various parasites have been described, there is very little data for a putative manipulative parasite. It is necessary to study the molecular interaction between a manipulative parasite and its host to better understand how such alterations evolve. MethodsHere, we used proteomics to characterize the secretome of a model cestode with a complex life cycle based on trophic transmission. We studied Schistocephalus solidus during the life stage in which behavioural changes take place in its obligatory intermediate fish host, the threespine stickleback (Gasterosteus aculeatus). We produced a novel genome sequence and assembly of S. solidus to improve protein coding gene prediction and annotation for this parasite. We then described the whole worms proteome and its secretome during fish host infection using LC-MS/MS. ResultsA total of 2 290 proteins were detected in the proteome of S. solidus, and 30 additional proteins were detected specifically in the secretome. We found that the secretome contains proteases, proteins with neural and immune functions, as well as proteins involved in cell communication. We detected Receptor-type tyrosine-protein phosphatases, which were reported in other parasitic systems to be manipulation factors. We also detected 12 S. solidus-specific proteins in the secretome that may play important roles in host-parasite interactions. ConclusionsOur results suggest that S. solidus liberates molecules with putative host manipulation functions in the host and that many of them are species specific.

genomics↗

bioRxiv2020

Honey bee queen production: Canadian costing case study and profitability analysis

The recent decline in honey bee (Hymenoptera: Apidae) colony health worldwide has had a significant impact on the beekeeping industry as well as on pollination-dependent crop sectors in North America and Europe. The pollinator crisis has been attributed to many environmental and anthropological factors including less nutrient rich agricultural monocultures, pesticide exposure, new parasite and pathogen infestations as well as beekeeper management and weather. Canadian beekeepers have indicated that issues with honey bee queens are the most significant factor affecting their colony health. In Canada, beekeepers manage colony losses by relying on the importation of foreign bees, particularly queens from warmer climates, to lead new replacement colonies. Unfortunately, the risks associated with imported queens include the introduction of new and potentially resistant pests and diseases, undesirable genetics including bees with limited adaptations to Canadas unique climate and bees negatively affected by transportation. Importing a large proportion of our queens each year also creates an unsustainable dependency on foreign bee sources, putting our beekeeping and pollination sectors at an even greater risk in the case of border closures and restrictions. Increasing the domestic supply of queens is one mitigation strategy that could provide Canadian beekeepers, farmers and consumers with a greater level of agricultural stability through locally bred, healthier queens. Our study is the first rigorous analysis of the economic feasibility of Canadian queen production. We present the costs of queen production for three case study operations across Canada over two years as well as the profitability implications. Our results show that for a small to medium sized queen production operation in Canada, producing queen cells and mated queens can be profitable. Using a mated queen market price ranging from $30 to $50, a producer selling mated queens could earn a profit of between $2 and $40 per queen depending on price and the cost structure of his operation. If the producer chose to rear queens for his own operation, the cost savings would also be significant as imported queen prices continue to rise. Our case studies reveal that there is potential for both skilled labour acquisition over time in queen production as well as cost savings from economies of scale. Our queen producers also reduced their production costs by re-using materials year to year. Domestic queen production could be one viable strategy to help address the current pollinator crisis in Canada.

ecology↗

bioRxiv2019

Profiling the E. coli Membrane Interactome Captured in Peptidisc Libraries

Protein-correlation-profiling (PCP), in combination with quantitative proteomics, has emerged as a high-throughput method for the rapid identification of dynamic protein complexes in native conditions. While PCP has been successfully applied to soluble proteomes, characterization of the membrane interactome has lagged, partly due to the necessary use of detergents to maintain protein solubility. Here, we apply the peptidisc, a one-size fits all membrane mimetic, for the capture of the Escherichia coli cell envelope proteome and its high-resolution fractionation in the absence of detergent. Analysis of the SILAC-labeled peptidisc library via PCP allows generation of over 4900 possible binary interactions out of >700,000 random associations. Using well-characterized membrane protein systems such as the SecY translocon, the Bam complex and the MetNI transporter, we find our dataset very useful for identifying transient and surprisingly novel protein interactions. For example, we discover a trans-periplasmic super-complex comprising subunits of the Bam and Sec translocons, including membrane-bound chaperones YfgM and PpiD. We identify RcsF and OmpA as bone fide interactors of BamA, and we show that interaction of MetQ with the ABC transporter MetNI depends on its N-terminal lipid anchor. We also discover NlpA as a novel interactor of MetNIQ. Most of these interactions are largely undetected by standard detergent-based purification. Together, the peptidisc workflow applied to the proteomic field is emerging as a promising novel approach to characterize membrane protein interactions under native expression conditions and without genetic manipulation.

biochemistry↗

bioRxiv2018

Glycan cross-feeding drives mutualism between Fusobacterium and the vaginal microbiota

Dysbiosis of the vaginal microbiome is associated with vaginal colonization by potential pathogens including Fusobacterium nucleatum, a bacterium linked with intrauterine infection and preterm birth. However, mechanisms by which such pathogens gain a foothold in the dysbiotic vagina remain obscure. Here we demonstrate that sialidase activity, a biochemical marker of vaginal dysbiosis, promoted F. nucleatum foraging on mammalian sialoglycans, an otherwise inaccessible resource. In mice with sialidase-positive vaginal microbiomes, mutant F. nucleatum unable to consume sialic acids displayed impaired colonization. Furthermore, community- and co-culture experiments showed that F. nucleatum did not simply take advantage of sialidase-positive bacteria, but also \"gave back\" to the community, supporting robust outgrowth of sialidase-producers, including Gardnerella vaginalis. These results illustrate that mutualistic relationships between vaginal bacteria support pathogen colonization and reinforce dysbiosis, adding complexity to the simplistic dogma that the mere absence of \"healthy\" lactobacilli is what creates a permissive environment for pathogens during dysbiosis.

microbiology↗