Biology subjects

Rangel, J.

Publications and source records attributed to Rangel, J..

7 recordsLinked to original sources

bioRxiv2025

A non-destructive approach to assess the gut microbiome of honey bee (Apis mellifera) queens using fecal samples

Fecal sampling is a widely used, non-invasive method for assessing gut microbiomes across various organisms. However, its suitability for studying the gut microbiome of honey bee (Apis mellifera) queens has not been tested. In this study, we evaluated whether fecal microbiomes accurately reflect gut microbiomes in honey bee queens, offering a potential non-destructive approach for microbiome research. We successfully obtained fecal and gut samples from 21 out of 26 queens. Bacterial communities were analyzed using 16S rRNA amplicon sequencing and qPCR. Our results indicate that queen fecal microbiomes closely resemble gut microbiomes, with no significant differences in alpha diversity and only minor differences in specific bacterial taxa. Beta diversity analyses revealed that within-pair microbiomes (i.e., gut vs. feces from the same queen) were significantly more similar than between-pair comparisons. Additionally, qPCR analyses revealed a strong positive correlation between bacterial abundances in fecal and gut samples, further supporting the use of feces as a proxy for gut microbiome composition. While promising, fecal collection from queens can sometimes be challenging. In our study, we were unable to collect feces from five queens, and these individuals lacked stored fecal material upon inspection of dissected guts. Nonetheless, our findings suggest that fecal sampling can be a useful, non-invasive method for studying honey bee queen microbiomes, enabling longitudinal assessments without compromising colony stability. ImportanceThe gut microbiome plays important roles in honey bee health, including protection against pathogens and stimulation of host physiological pathways. Because gut microbiome analysis involves destructive dissections, most research has focused on workers, given that colonies can have tens of thousands of individuals. This has left a significant gap in microbiome studies of other colony members, such as queens. Given that a queen is the sole reproductive female, her gut microbiome cannot be sampled without compromising colony integrity. In this study, we demonstrate that fecal sampling from honey bee queens provides a reliable, non-destructive alternative for assessing the composition of their gut microbiomes. We found that queen fecal microbiomes closely resemble their gut microbiomes in both taxonomic diversity and composition. This approach enables longitudinal monitoring of queen microbiomes without disrupting colony integrity, offering a valuable tool for honey bee research.

microbiology↗

bioRxiv2024

Varroa mites escape the evolutionary trap of haplodiploidy

Genetic diversity is essential for populations adapting to environmental-changes. Following genetic bottlenecks, invasive species often have reduced diversity, yet must rapidly adapt to novel environments. This paradox is especially pronounced in parasites, which face repeated transmission bottlenecks and anthropogenic countermeasures. The challenge of maintaining diversity in the short-term intensifies in haplodiploid species, where males inherit and transmit only half of their mothers genome, limiting effective population size. To examine how such species may maintain adaptability, we studied inheritance in Varroa mites (Varroa destructor), globally invasive honey bee parasite. Using three-generation pedigrees, we found that Varroa is not haplodiploid, as previously thought. Rather, females produce diploid sons who transmit either maternal allele to daughters. This system slows reduced heterozygosity loss under sib-mating, compared to ancestral haplodiploidy, increasing effective population size and adaptability. Our findings reveal a rare reversion from haplodiploidy, long considered an evolutionary end state, and suggest reproductive plasticity underlies the resilience of invasive parasites like Varroa.

evolutionary biology↗

bioRxiv2024

Solvation Free Energy in Governing Equations for DNA Hybridization, Protein-Ligand Binding, and Protein Folding

This work examines the thermodynamics of model biomolecular interactions using a governing equation that accounts for the participation of bulk water in the balanced reaction. In the first example, the binding affinities of two model DNA duplexes, one of nine and one of ten base pairs in length, are measured and characterized by isothermal titration calorimetry as a function of concentration. The results indicate that the change in solvation free energy that accompanies duplex formation ({Delta}GS) is large and unfavorable. When normalized to the number of base pairs, the duplex with the larger number of G:C pairings yields the largest change in solvation free energy, {Delta}GS = +460 kcal/mol/base pair at 25 {degrees}C. A modelling study demonstrates how the solvation free energy alters the output of a typical titration experiment. Hybridization measurements are completed at four different temperatures, however a vant Hoff analysis of the data is complicated by the varying degree of intramolecular base stacking within each DNA strand as a function of temperature. The same thermodynamic framework is applied to a model protein- ligand interaction, the binding of ribonuclease A with the nucleotide inhibitor 3-UMP, and to a conformational equilibrium, the change in tertiary structure of -lactalbumin in molar guanidinium chloride solutions. The ribonuclease study yields a value of {Delta}GS = +160 kcal/mol, whereas the folding equilibrium yields {Delta}GS {approx} 0, an apparent characteristic of hydrophobic interactions. These examples complement previous applications of the governing equation to the interaction of smaller molecules and demonstrate the importance of solvation energy in biothermodynamics.

biochemistry↗

bioRxiv2023

Beyond conflict: kinship theory of intragenomic conflict predicts individual variation in altruistic behavior

Studies of the genetic basis of behavioral variation have emphasized gene cooperation within networks, often overlooking gene conflicts. The Kinship Theory of Intragenomic Conflict (KTIC) proposes that conflicts can occur within genes when parent-specific alleles have different strategies for maximizing reproductive fitness. Here, we test a prediction of the KTIC - that selection should favor alleles which promote "altruistic" behaviors that support the reproductive fitness of kin. In honey bee (Apis mellifera) colonies, workers act altruistically when tending to the queen by performing a "retinue" behavior, distributing the queens mandibular pheromone (QMP) throughout the hive. Workers exposed to QMP do not activate their ovaries, ensuring they care for the queens brood instead of competing to lay unfertilized eggs. Thus, the KTIC predicts that response to QMP should be favored by the maternal genome. Using a reciprocal cross design, we tested for parent-of-origin effects on the workers 1) responsiveness to QMP, 2) ovary activation, and 3) brain transcriptome. We hypothesized that QMP-responsive workers have smaller and less active ovaries, influenced by the workers parent-of-origin. With an allele-specific transcriptomic analysis, we tested whether QMP-responsive workers show enriched maternal allele-biased gene expression compared to QMP-unresponsive workers. Finally, we explored how parent-of-origin gene expression patterns are associated with overall gene expression patterns and regulatory networks. We report evidence in support of the KTIC for the retinue behavior and associated conflicts within gene networks. Our study provides new insights into the genetic basis of behavior and the potential for behavioral variation influenced by intragenomic conflict.

animal behavior and cognition↗

bioRxiv2019

Population-scale prediabetic assessment using HbA1c from menstrual blood

CDC-recommended diabetes prevention programs aim to detect and reverse disease in the one-third of Americans with prediabetes, but high-compliance serial assessment of percent hemoglobin A1c (HbA1c) remains a barrier to delivering this vision at population scale. Venous phlebotomy is challenging for busy or resource-constrained patients.\n\nIn this paper, we introduce the first-ever quantitative diagnostic test based on menstrual fluid, which allows HbA1c quantification from self-collected mailed tampons.We demonstrate that menstrual HbA1c is comparable to venous HbA1c in the diagnosis of prediabetes with the standard threshold of 5.7. We also demonstrate accuracy, precision, stability, and interference testing. Finally, surveying subjects reveals strong preference for menstrual HbA1c in quarterly testing. These findings suggest that menstrual HbA1c can be a key tool in addressing prediabetes at population scale.

pathology↗

bioRxiv2019

Honey bee (Apis mellifera) larval pheromones regulate gene expression related to foraging task specialization

BackgroundForaging behavior in honey bees (Apis mellifera) is a complex phenotype which is regulated by physiological state and social signals. How these factors are integrated at the molecular level to modulate foraging behavior has not been well-characterized. The transition of worker bees from nursing to foraging behavior is mediated by large-scale changes in brain gene expression, which are influenced by pheromones produced by the queen and larvae. Larval pheromones can also stimulate foragers to leave the colony to collect pollen, but the mechanisms underpinning this rapid behavioral plasticity are unknown. Furthermore, the mechanisms through which foragers specialize on collecting nectar or pollen, and how larval pheromones impact these different behavioral states, remains to be determined. Here, we investigated the patterns of gene expression related to rapid behavioral plasticity and task allocation among honey bee foragers exposed to two larval pheromones, brood pheromone (BP) and (E)-beta-ocimene (EBO).\n\nResultsWe hypothesized that both pheromones would alter expression of genes in the brain related to foraging and would differentially impact expression of genes in the brains of pollen compared to nectar foragers. Combining data reduction, clustering, and network analysis methods, we found that foraging preference (nectar vs. pollen) and pheromone exposure are each associated with specific brain gene expression profiles. Furthermore, pheromone exposure has a strong transcriptional effect on genes that are preferentially expressed in nectar foragers. Representation factor analysis between our study and previous landmark honey bee transcriptome studies revealed significant overlaps for both pheromone communication and foraging task specialization.\n\nConclusionsSocial signals (i.e. pheromones) may invoke foraging-related genes to upregulate pollen foraging at both long and short time scales. These results provide new insights into how social signals integrate with task specialization at the molecular level and highlights the important role that brain gene expression plays in behavioral plasticity across time scales.

genomics↗

bioRxiv2018

Parallel genomic evolution of parasite tolerance in wild honey bee populations

Sudden biotic pressures, such as those from novel diseases and pathogens, require populations to respond rapidly or face potential extinction. How this response process takes place remains poorly understood, particularly in natural environments. In this study we take advantage of unique decade-long data sets of two wild honey bee (Apis mellifera) populations in the United States to reconstruct the evolution of tolerance to a novel parasite, the ectoparasitic mite Varroa destructor. Upon the arrival of Varroa, the two geographically isolated populations simultaneously suffered massive Varroa-induced mortality, but stabilized within two years. Here we sequenced and phased genomes of 465 bees sampled from both populations annually over the decade that spanned Varroas arrival. Remarkably, we found that genetic changes were strongly correlated between the populations, suggesting parallel selective responses to Varroa parasitization. The arrival of Varroa was also correlated with an influx of genes of African origin into both populations, though surprisingly it did not substantially contribute to the overall similarity of the evolutionary response between them. Genes involved in metabolic, protein processing and developmental pathways were under particularly strong selection. It is possible that interactions among highly connected gene groups in these pathways may help channelize selective responses to novel parasites, causing completely unrelated populations to exhibit parallel evolutionary trajectories when faced with the same biotic pressure. Our analyses illustrate that ecologically relevant traits emerge from highly polygenic selection involving thousands of genes contributing to complex patterns of evolutionary change.

evolutionary biology↗