Biology subjects

Sundstrom, K.

Publications and source records attributed to Sundstrom, K..

3 recordsLinked to original sources

bioRxiv2026

When clades collide: Genomic admixture in blacklegged ticks (Ixodes scapularis) from the Great Plains

Ixodes scapularis ticks transmit a number of pathogens important to human health, including Borrelia burgdorferi, the causative agent of Lyme disease. While I. scapularis is found across the Eastern United States, Lyme disease transmission is largely limited to the Northeast and Upper Midwest and is nearly absent in the South. This indicates that differences in northern versus southern clades of I. scapularis are associated with differences in Lyme disease transmission risk. I. scapularis is undergoing range expansion, including into the Great Plains region of the United States. Determining where I. scapularis populations in the Great Plains originated can inform future risk of Lyme disease transmission in this region. In this study, we use a population genomics framework to characterize diversity, structure, and B. burgdorferi infection rates of I. scapularis populations in the Great Plains region. We generated whole genome sequence data and single nucleotide polymorphism (SNP) datasets from I. scapularis ticks collected in Iowa, Kansas, Nebraska, and South Dakota to compare to publicly available data from across the species range. Our analysis of 200 I. scapularis SNP datasets indicated geographically well-defined populations that correspond to historical northern and southern ancestral clades of I. scapularis. Ticks from South Dakota, Iowa, and northeastern Nebraska are genetically similar populations from the Upper Midwest, while ticks from Kansas are more genetically similar to ticks from the Southeast. Ticks collected in the central eastern region of Nebraska, however, represent an evenly admixed population of both northern and southern genomic backgrounds. Analysis of B. burgdorferi reads from genomic datasets shows [~]50% infection rate in ticks from Iowa and northeastern Nebraska, whereas ticks from Kansas show no evidence of B. burgdorferi infection. Of note, evenly admixed ticks from the central eastern region of Nebraska also show no evidence of B. burgdorferi infection. These results provide further evidence that tick genomics may influence traits associated with B. burgdorferi infection status, and thus the potential for Lyme disease transmission. As the range of I. scapularis continues to expand, bringing historically isolated populations into contact, there is a clear need to understand the consequence of genomic admixture for B. burgdorferi transmission potential to inform future risk of Lyme disease in the United States.

genomics↗

bioRxiv2025

Hive-associated bacteria improve honeybee survival during Paenibacillus larvae infection

Honeybees (Apis mellifera L.) are the most common pollinators of crops. Honeybee larvae are susceptible to Paenibacillus larvae, a spore-forming Gram-positive bacterium that causes American Foulbrood (AFB), one of the most destructive brood diseases worldwide. Existing antibiotic treatments are undesirable due to increasing pathogen resistance and their residual accumulation in bee products. Consequently, there is increasing interest in biological agents and natural strategies for AFB control. However, most studies remain limited to in vitro or in vivo experiments and rarely evaluate impacts on adult bees. In this study, we systematically investigated hive-associated bacteria for their potential to enhance larval survival during P. larvae infection. Bacteria isolated from AFB-infected combs were sequenced and screened for antagonistic activity. Several Bacillus species--including B. zhangzhouensis, B. subtilis, B. amyloliquefaciens, B. licheniformis, and B. mojavensis--inhibited one or more P. larvae strains. Notably, the lysate of B. licheniformis suppressed all tested strains; Further characterization revealed that its main antibacterial component consists of heat-stable proteins between 30-50 kDa. Two Bacillus strains were selected for larval infection assays using laboratory-reared honeybee larvae: both significantly improved survival by 42% and 71%, respectively. To evaluate potential effects on adult bees, newly emerged workers were caged and fed B. licheniformis ASx lysate. Their survival differed from that of untreated controls but remained comparable to the Terra-Pro-fed bees, a Terramycin-based AFB treatment, and their gut microbiome remained similar to that of untreated controls. Overall, our findings suggest that hive-associated Bacillus species offer promising, low-impact candidates for AFB disease management.

microbiology↗

bioRxiv2024

Spatiotemporal dynamic models of Amblyomma americanum questing activity in the Central Great Plains

Ticks represent important vectors of a number of bacterial and viral disease agents, owing to their hematophagous nature and their questing behavior (the process in which they seek new hosts). Questing activity is notably seasonal with spatiotemporal dynamics that needs to be understood in detail as part of mediating and mitigating tick-borne disease risk. Models of the geography of tick questing activity developed to date, however, have ignored the temporal dimensions of that behavior; more fundamentally, they have often not considered the sampling underlying available occurrence data. Here, we have addressed these shortfalls for Amblyomma americanum, the most commonly encountered tick in the central Great Plains, via (1) detailed, longitudinal sampling to characterize the spatiotemporal dimensions of tick questing activity; (2) randomization tests to establish in which environmental dimensions a species is manifesting selective use; and (3) modeling methods that include both presence data and absence data, taking fullest advantage of the information available in the data resource. The outcome was a detailed picture of geographic and temporal variation in suitability for the species through the two-year course of this study. Such models that take full advantage of available information will be crucial in understanding the risk of tick-borne disease into the future.

ecology↗