Large Population Sizes Research Articles

Population structure and adaptive differentiation in the sea cucumber Apostichopus californicus and implications for spatial resource management.

A growing body of evidence suggests that spatial population structure can develop in marine species despite large population sizes and high gene flow. Characterizing population structure is important for the effective management of exploited species, as it can be used to identify appropriate scales of management in fishery and aquaculture contexts. The California sea cucumber, Apostichopus californicus, is one such exploited species whose management could benefit from further characterization of population structure. Using restriction site-associated DNA (RAD) sequencing, we developed 2075 single nucleotide polymorphisms (SNPs) to quantify genetic structure over a broad section of the species' range along the North American west coast and within the Salish Sea, a region supporting the Washington State A. californicus fishery and developing aquaculture production of the species. We found evidence for population structure (global fixation index (FST) = 0.0068) with limited dispersal driving two patterns of differentiation: isolation-by-distance and a latitudinal gradient of differentiation. Notably, we found detectable population differences among collection sites within the Salish Sea (pairwise FST = 0.001-0.006). Using FST outlier detection and gene-environment association, we identified 10.2% of total SNPs as putatively adaptive. Environmental variables (e.g., temperature, salinity) from the sea surface were more correlated with genetic variation than those same variables measured near the benthos, suggesting that selection on pelagic larvae may drive adaptive differentiation to a greater degree than selection on adults. Our results were consistent with previous estimates of and patterns in population structure for this species in other extents of the range. Additionally, we found that patterns of neutral and adaptive differentiation co-varied, suggesting that adaptive barriers may limit dispersal. Our study provides guidance to decision-makers regarding the designation of management units for A. californicus and adds to the growing body of literature identifying genetic population differentiation in marine species despite large, nominally connected populations.

Quantum Inspired Evolutionary Algorithm with a Novel Elitist Local Search Method for Scheduling of Thermal Units

The unit commitment problem is a complex and essential problem in the power generation field, which is solved to obtain the schedule of a large number of generating units to minimize the operating cost and the fulfillment of consumer load demand. The present work solves the unit commitment problem using quantum-inspired evolutionary algorithms with a novel elitist local search method (QIEA-ELS). The proposed algorithm solves the unit commitment problem efficiently and its applicability is verified on various unit test systems. The constraints are satisfied efficiently to find a feasible solution, the novel elitist search method is used to locally explore the search area around the fittest individual to find a better solution in its vicinity in genotype space represent by qubits. The solution of the unit commitment is carried out considering two small population sizes as suggested in earlier work by other authors using QIEA, though it can be extended using larger population size also. The computational time is also reduced by using the suggested method with a novel elitist local search (ELS) method. The results obtained after applying the proposed algorithm are found to better as compared to other well-known solution techniques.

Large effective population size masks population genetic structure in Hirondellea amphipods within the deepest marine ecosystem, the Mariana Trench.

The examination of genetic structure in the deep-ocean hadal zone has focused on divergence between tectonic trenches to understand how environment and geography may drive species divergence and promote endemism. There has been little attempt to examine localized genetic structure within trenches, partly because of logistical challenges associated with sampling at an appropriate scale, and the large effective population sizes of species that can be sampled adequately may mask underlying genetic structure. Here we examine genetic structure in the superabundant amphipod Hirondellea gigas in the Mariana Trench at depths of 8126-10,545 m. RAD sequencing was used to identify 3182 loci containing 43,408 single nucleotide polymorphisms (SNPs) across individuals after stringent pruning of loci to prevent paralogous multicopy genomic regions being erroneously merged. Principal components analysis of SNP genotypes resolved no genetic structure between sampling locations, consistent with a signature of panmixia. However, discriminant analysis of principal components identified divergence between all sites driven by 301 outlier SNPs in 169 loci and significantly associated with latitude and depth. Functional annotation of loci identified differences between singleton loci used in analysis and paralogous loci pruned from the data set and also between outlier and nonoutlier loci, all consistent with hypotheses explaining the role of transposable elements driving genome dynamics. This study challenges the traditional perspective that highly abundant amphipods within a trench form a single panmictic population. We discuss the findings in relation to eco-evolutionary and ontogenetic processes operating in the deep sea, and highlight key challenges associated with population genetic analysis in nonmodel systems with inherent large effective population sizes and genomes.

Abstract P1-05-02: Reducing Delays of Breast Cancer Care Using An Innovative Digital Health Platform

Abstract Background: For breast cancer patients, prolonged time from core needle biopsy to initiation of treatment is associated with an incremental decrease in overall survival. This overall survival reduction disproportionately affects patients with stage I and II breast cancer (hazard ratio: 1.09-1.16, p< 0.001), the subgroup of breast cancer patients for which a survival reduction would be least expected due to its early stage and least accepted due to its large population size and potential increased cost of healthcare. Materials and Methods: We conducted an IRB-approved quality improvement initiative among patients with Medicare Advantage at a large integrated healthcare organization in Nevada to assess the ability of an innovative digital health platform to reduce the time interval between positive core needle biopsy to initiation of breast cancer treatment compared to a historical cohort of Medicare Advantage patients diagnosed and treated at the same facility over the preceding 6-month period. The study was restricted to women evaluated at a single contracted breast imaging center for inconclusive (Bi-RADS 0) and suspicious (BI-RADS 4 & 5) mammograms, ultrasound, and/or breast MRI. Time to treatment (TTT) calculations were limited to the subset of patients diagnosed with in situ and invasive breast cancer by core needle biopsy. The primary goal was to reduce the historical TTT by greater than 50%. A secondary goal was to reduce TTT to < 30 days, well below the interval where overall survival would be adversely affected. Results: Between September 2021 and April 2022, 552 patients with BI-RADS 0, 4, and 5 breast imaging were enrolled in the quality improvement initiative and managed on the XpediteMD digital health platform. 208 patients were designated as BI-RADS 4 or 5 (i.e., suspicious imaging findings), all of whom ultimately underwent a diagnostic core needle biopsy. Of these, 75 patients were found to have invasive or in situ breast cancer and were subsequently referred to surgery or medical oncology where treatment was initiated. Among these patients, average TTT was 32 days with use of the digital health platform compared to 74 days in the historical cohort, a statistically significant 57% reduction in TTT, exceeding the 50% TTT goal. Although the study did not meet the target goal of average TTT < 30 days from needle biopsy to initiation of treatment, failure to achieve this goal was largely attributable to 3 patients who elected to delay cancer therapy for personal or health reasons. Excluding these 3 patients would have yielded an average TTT of 28.75 days, which is within our < 30-day goal. Conclusions: This quality improvement initiative demonstrated the successful deployment of a novel digital health platform which achieved a 57% reduction in the time interval from a positive core needle biopsy to performance of breast cancer surgery or initiation of systemic therapy. By reducing TTT to 32 days, the initiative eliminated any delay in initiation of cancer therapy that could have compromised patients’ overall survival. Citation Format: Dennis R. Holmes, Riya Pulicharam. Reducing Delays of Breast Cancer Care Using An Innovative Digital Health Platform [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-05-02.

Effect of The Keller Funnel Method “No Touch” on Breast Augmentation and Reconstruction: A Systematic Review

Introduction: Breast augmentation is one of the most common aesthetic surgeries. Implant contamination remains a critical problem with these surgeries resulting in acute infection as well as capsular contracture. To reduce the risk of implant contamination, the “no-touch technique” utilizing the Keller funnel© has been adopted by many surgeons. This systematic review aims to investigate the advantages of the Keller Funnel method for breast augmentation-reconstruction. Materials and Methods: A systematic review of PubMed, EMBASE, the Cochrane database, and Google Scholar was performed between years 2005 to 2021. All clinical-based, retrospective and prospective studies utilizing the Keller Funnel method for breast implant insertion were selected. Results: Six studies were identified for evaluation: 5 were retrospective cohorts and 1 was prospective trial. No randomized controlled trials were found. Outcomes reported included less rates of capsular contracture (RR:0.42; P=0.0006, %95 CI=0.25-0.69), decreased levels of contamination and implant shell trauma, shorter incision lengths (35.5+/-2.1mm), less insertion time (mean=6 s), decreased complications, and ultimately greater patient satisfaction with outcomes. Conclusion: This review suggests that the Keller Funnel is a useful method “no-touch” breast augmentation and reconstruction surgery. The Keller funnel reduces bacterial contamination and subsequent capsular contracture rate, surgical time, and incision length as well as allows for easier insertion. All of these mitigate the variables that lead to reoperation. However, our findings support recommendation of a prospective randomized controlled clinical trial with larger population size and follow-up intervals.

Whole-genome sequencing reveals a complex African population demographic history and signatures of local adaptation.

We conduct high coverage (>30×) whole-genome sequencing of 180 individuals from 12 indigenous African populations. We identify millions of unreported variants, many predicted to be functionally important. We observe that the ancestors of southern African San and central African rainforest hunter-gatherers (RHG) diverged from other populations >200 kya and maintained a large effective population size. We observe evidence for ancient population structure in Africa and for multiple introgression events from "ghost" populations with highly diverged genetic lineages. Although currently geographically isolated, we observe evidence for gene flow between eastern and southern Khoesan-speaking hunter-gatherer populations lasting until ∼12kya. We identify signatures of local adaptation for traits related to skin color, immune response, height, and metabolic processes. We identify a positively selected variant in the lightly pigmented San that influences pigmentation invitro by regulating the enhancer activity and gene expression of PDPK1.

Reduced Pain and Improved Function Following Short-Term Use of Noninvasive BioWave High Frequency Peripheral Nerve Stimulation for Pain Management.

The peripheral nervous system is an increasingly popular target for chronic pain treatment modalities. Noninvasive neuromodulation has shown promise at providing significant chronic pain relief with a much safer side effect profile. This retrospective pilot study is shaped around a noninvasive neuromodulation system over a 2-week treatment timeline. Open-label survey of chronic pain patients recruited from Veteran Affairs, orthopedic, and pain health systems. If a noninvasive neuromodulation system was prescribed the patients were then offered a 2-week follow-up survey. This voluntary survey did not affect their therapy duration or quality. This survey was designed to address similar metrics as smaller noninvasive neuromodulation studies to allow a quality comparison while giving more power with a large population size of 1511 patients. Overall pain scores (including before and after scores), satisfaction level, desire to continue therapy, medication use, effect on functional metrics (mood, sleep, sit, stand, walk, and lift), and activities of daily living (ADL) scores were assessed. The results demonstrated an overall pain reduction of 46%. All functional metrics were improved throughout with the largest improvements reported in mood and sleep at over 47%. Medication use was reported as decreased or eliminated in 42% of patients. There were no adverse reactions or complications reported over the 1511 patients. This survey is amongst the largest population sizes every studied for noninvasive neuromodulation. Within just 2weeks patients can see a reduction in overall pain and medication needs. Although survey studies have inherent limitations such as duration and compliance biases with such an overwhelming benefit in every category we believe that noninvasive neuromodulation therapy is a promising, safe, and cost-effective therapy. Future studies should focus on long-term follow-ups and post-therapy pain scores with a placebo group.

Watermelon Root Exudates Enhance Root Colonization of Bacillus amyloliquefaciens TR2.

Bacillus amyloliquefaciens TR2, one of plant growth-promoting rhizobacteria (PGPR), is capable of colonizing plant roots in a large population size. However, the interaction of watermelon root exudates and colonization of the strain TR2 has not yet been clearly elucidated. In this investigation, we demonstrated that B. amyloliquefaciens TR2 promoted watermelon plants growth and exhibited biocontrol efficacy against watermelon Fusarium wilt under greenhouse conditions. Collected watermelon root exudates significantly induced chemotaxis, swarming motility, and biofilm formation of the strain TR2. We also tested the components of root exudates (organic acids: malic acid, citric acid, succinic acid, and fumaric acid; amino acids: methionine, glutamic acid, alanine, and aspartic acid; phenolic acid: benzoic acid) and the results showed that a majority of these compounds could promote chemotactic response, swarming motility, and biofilm formation in a different degree. Benzoic acid induced the strongest chemotactic response; however, the swarming motility and biofilm formation of the strain TR2 were maximumly enhanced by supplement of fumaric acid and glutamic acid, respectively. In addition, the root colonization examination indicated that the population of B. amyloliquefaciens TR2 colonized on watermelon root surfaces was dramatically increased by adding concentrated watermelon root exudates. In summary, our studies provide evidence suggesting that root exudates are important for colonization of B. amyloliquefaciens TR2 on plant roots and help us to understand the interaction between plants and beneficial bacteria.

De Novo Assembly and Characterization of the Transcriptome of an Omnivorous Camel Cricket (Tachycines meditationis).

Tachycines meditationis (Orthoptera: Rhaphidophoridae: Tachycines) is a widely distributed insect in eastern Asia. This species is common in urban environments, and its unique omnivorous diet may contribute to its success in various habitats. However, molecular studies on the species are scarce. Here, we obtained the first transcriptome sequence of T. meditationis and performed preliminary analyses to test whether the evolution of coding sequences fits the expectations based on the species' ecology. We retrieved 476,495 effective transcripts and annotated 46,593 coding sequences (CDS). We analysed the codon usage and found that directional mutation pressure was the leading cause of codon usage bias in this species. This genome-wide relaxed codon usage pattern in T. meditationis is surprising, given the potentially large population size of this species. Moreover, despite the omnivorous diet, the chemosensory genes of this species do not exhibit codon usage deviating significantly from the genome-level pattern. They also do not seem to experience more gene family expansion than other cave cricket species do. A thorough search for rapidly evolved genes using the dN/dS value showed that genes associated with substance synthesis and metabolic pathways, such as retinol metabolism, aminoacyl-tRNA biosynthesis, and fatty acid metabolism, underwent species-specific positive selection. While some results seem to contradict the species ecology, our transcriptome assembly provides a valuable molecular resource for future studies on camel cricket evolution and molecular genetics for feeding ecology in insects, in general.

Genetic diversity and population histories of two species of Phidippus (Araneae: Salticidae) from northwestern Mexico

The northwestern Mexican Baja California state is an ecologically unique area being the only part of the country with a Mediterranean ecosystem and a high species diversity and endemism for many groups. Studies on the biodiversity of the region are scarce, especially regarding ecologically important groups such as terrestrial arthropods. Even scarcer are studies on another important aspect of diversity, namely genetic diversity. Due to the paucity of information, the genetic diversity and population histories of the 2 most abundant species of Phidippus (Araneae: Salticidae) of the region are presented, based on nuclear and mitochondrial DNA data. Phidippus johnsoni, the more widespread of the 2, belonged to 1 large, panmictic population in Baja California, while P. phoenix was divided into 2 populations. Both species have high genetic diversity and estimated large population sizes, which increased during the last 150,000 years for P. johnsoni, and the last 30,000 years, after the Last Glacial Maximum for P. phoenix. This study, therefore, reinforces the importance of this area, not only for its species diversity but also for the genetic diversity found within the populations, which reflects ecological stability during the Pleistocene, allowing for the accumulation of genetic diversity through time.

Evolutionary rescue and geographic range shifts under climate change for global amphibians

By the end of this century, human-induced climate change and habitat loss may drastically reduce biodiversity, with expected effects on many amphibian lineages. One of these effects is the shift in the geographic distributions of species when tracking suitable climates. Here, we employ a macroecological approach to dynamically model geographic range shifts by coupling ecological niche models and eco-evolutionary mechanisms, aiming to assess the probability of evolutionary rescue (i.e., rapid adaptation) and dispersal under climate change. Evolutionary models estimated the probability of population persistence by adapting to changes in the temperature influenced by precipitation in the following decades, while compensating the fitness reduction and maintaining viable populations in the new climates. In addition, we evaluated emerging patterns of species richness and turnover at the assemblage level. Our approach was able to identify which amphibian populations among 7,193 species at the global scale could adapt to temperature changes or disperse into suitable regions in the future. Without evolutionary adaptation and dispersal, 47.7% of the species could go extinct until the year 2,100, whereas adding both processes will slightly decrease this extinction rate to 36.5%. Although adaptation to climate is possible for populations in about 25.7% of species, evolutionary rescue is the only possibility to avoid extinction in 4.2% of them. Dispersal will allow geographic range shifts for 49.7% of species, but only 6.5% may avoid extinction by reaching climatically suitable environments. This reconfiguration of species distributions and their persistence creates new assemblage-level patterns at the local scale. Temporal beta-diversity across the globe showed relatively low levels of species turnover, mainly due to the loss of species. Despite limitations with obtaining data, our approach provides more realistic assessments of species responses to ongoing climate changes. It shows that, although dispersal and evolutionary rescue may attenuate species losses, they are not enough to avoid a significant reduction of species’ geographic ranges in the future. Actions that guarantee a higher potential of adaptation (e.g., genetic diversity through larger population sizes) and increased connectivity for species dispersion to track suitable climates become essential, increasing the resilience of biodiversity to climate change.

Genetic population structures of common scavenging species near hydrothermal vents in the Okinawa Trough

Deep-sea mining of hydrothermal deposits off the coast of Japan is currently under consideration, and environmental baseline studies of the area are required to understand possible impacts. The aim of this study is to clarify population structures of dominant benthic megafaunal species near hydrothermal vent fields in the Okinawa Trough, using a population genetics approach. We examined dominant deep-sea scavenging species including eels, several amphipods, and a decapod and performed population genetic analyses based on the mitochondrial cytochrome c oxidase subunit I region. Several sites were sampled within Okinawa Trough to examine intra-population diversity while two other locations 1400–2400 km away were chosen for inter-population comparisons. For synaphobranchid eels Simenchelys parasitica and Synaphobranchus kaupii, our results showed significant intra-population diversity but no inter-population genetic differentiation, suggesting strong genetic connectivity and/or large population sizes. In addition, single nucleotide polymorphism analysis also confirmed strong genetic connectivity for Simenchelys parasitica. Among scavenging amphipods, we detected seven putative species using molecular phylogenetic analysis. We evaluated population structures of the most abundant species of amphipods and a decapod species (Nematocarcinus lanceopes). Our results provide basic information on the genetic population structures of benthic megafaunal species near hydrothermal vent fields, which can be used to select candidate species for future connectivity analysis with high-resolution genetic markers and aid understanding of the potential population impacts of environmental disturbances.

Fifty Years of Global Cardiovascular Research in Africa: A Scientometric Analysis, 1971 to 2021.

Background To analyze the quantity and impact of cardiovascular research done in Africa or coauthored by researchers based in Africa, their determinants, and the patterns of research collaboration. Methods and Results We retrieved data from Web of Science and additional sources. We analyzed temporal trends from 1971 to 2021 and geographical distribution, research impact using country-level h-index, international research cooperation, and associations of research quantity and quality using linear regression. The annual volume of cardiovascular research from Africa has increased from 4 publications in 1971 to 3867 in 2020 and currently represents ~3% of the global cardiovascular research output. Authors from South Africa (28.1%) and Egypt (24.1%) accounted for more than half of all publications from African countries, and they had the highest h-index (209 and 111, respectively). Important collaborators outside Africa included the United States, United Kingdom, France, Germany, and Australia. The country's publication count was associated with larger population size (P<0.001), whereas the country's h-index was associated with larger population size (P=0.001) and higher human development index (P=0.023). International collaboration was dominated by the United States, South Africa, United Kingdom, Egypt, and Canada. The level of collaboration between African countries was lower than their collaboration with non-African countries. Conclusions Cardiovascular research output from African authors remains low, despite marked progress over the past 5 decades. These findings highlight the urgent need to improve the quantity and quality of cardiovascular research in Africa through increased investments, training of human resources, improved infrastructures, and expansion of collaborative research networks, particularly within Africa.

Bottlenecks can constrain and channel evolutionary paths.

Population bottlenecks are commonplace in experimental evolution, specifically in serial passaging experiments where microbial populations alternate between growth and dilution. Natural populations also experience such fluctuations caused by seasonality, resource limitation, or host-to-host transmission for pathogens. Yet, how unlimited growth with periodic bottlenecks influence the adaptation of populations is not fully understood. Here, we study theoretically the effects of bottlenecks on the accessibility of evolutionary paths and on the rate of evolution. We model an asexual population evolving on a minimal fitness landscape consisting of two types of beneficial mutations with the empirically supported trade-off between mutation rate and fitness advantage, in the regime where multiple beneficial mutations may segregate simultaneously. In the limit of large population sizes and small mutation rates, we show the existence of a unique most likely evolutionary scenario, determined by the size of the wild-type population at the beginning and at the end of each cycle. These two key demographic parameters determine which adaptive paths may be taken by the evolving population by controlling the supply of mutants during growth and the loss of mutants at the bottleneck. We do not only show that bottlenecks act as a deterministic control of evolutionary paths but also that each possible evolutionary scenario can be forced to occur by tuning demographic parameters. This work unveils the effects of demography on adaptation of periodically bottlenecked populations and can guide the design of evolution experiments.

Observations of movement and site fidelity of white-beaked dolphins (Lagenorhynchus albirostris) in Icelandic coastal waters using photo-identification

The white-beaked dolphin (Lagenorhynchus albirostris) is the most commonly sighted delphinid species in Icelandic coastal waters. However, little is known about the species’ abundance, site fidelity and movements throughout its range. Photo-identification studies were conducted from April– October (2002–10) during whalewatching operations in Faxaflói and Skjálfandi bays on the southwest and northeast coasts of Iceland, respectively. Minimum abundance, annual site fidelity and movement between bays were calculated. A total of 154 and 52 individuals were identified in Faxaflói and Skjálfandi bays, respectively. The annual re-sighting rate was 21.4% in Faxaflói bay while only one individual was re-sighted in Skjálfandi bay (1.7%). A total of five dolphins (2.3%) were matched between Faxaflói and Skjálfandi bays with the period between re-sightings ranging from 272 to 821 days (mean 28.16 days, SD = 5.94). Low site fidelity rates observed likely signify a much larger home range than the present study area, into either other coastal or offshore zones, or alternatively may be explained by a large natural population size and/or the opportunistic nature of sampling during this study. Therefore, expansion of the study area is required. The matches between bays suggest that white-beaked dolphins inhabit a largescale coastal range of the Icelandic coast and can be considered highly mobile and transient possibly due to scarce and patchy resources. Alternatively it could be due to a large population size.

The suppressive potential of a gene drive in populations of invasive social wasps is currently limited

Social insects are very successful invasive species, and the continued increase of global trade and transportation has exacerbated this problem. The yellow-legged hornet, Vespa velutina nigrithorax (henceforth Asian hornet), is drastically expanding its range in Western Europe. As an apex insect predator, this hornet poses a serious threat to the honey bee industry and endemic pollinators. Current suppression methods have proven too inefficient and expensive to limit its spread. Gene drives might be an effective tool to control this species, but their use has not yet been thoroughly investigated in social insects. Here, we built a model that matches the hornet’s life history and modelled the effect of different gene drive scenarios on an established invasive population. To test the broader applicability and sensitivity of the model, we also incorporated the invasive European paper wasp Polistes dominula. We find that, due to the haplodiploidy of social hymenopterans, only a gene drive targeting female fertility is promising for population control. Our results show that although a gene drive can suppress a social wasp population, it can only do so under fairly stringent gene drive-specific conditions. This is due to a combination of two factors: first, the large number of surviving offspring that social wasp colonies produce make it possible that, even with very limited formation of resistance alleles, such alleles can quickly spread and rescue the population. Second, due to social wasp life history, infertile individuals do not compete with fertile ones, allowing fertile individuals to maintain a large population size even when drive alleles are widespread. Nevertheless, continued improvements in gene drive technology may make it a promising method for the control of invasive social insects in the future.

Impacts of Bioassay Type on Insecticide Resistance Assessment in the German Cockroach (Blattodea: Ectobiidae).

The German cockroach, Blattella germanica (L.), is one of the most critical urban pests globally due to the health risks it imposes on people, such as asthma. Insecticides are known to manage large cockroach population sizes, but the rapid rate at which they develop resistance is a continuing problem. Dealing with insecticide resistance can be expensive and time-consuming for both the consumer and the pest management professional (PMP) applying the treatment. Each cockroach population is unique because different strains have different insecticide susceptibilities, so resistance profiles must be considered. This study addressed the above issue in a controlled laboratory setting. Cockroach strains from Indianapolis, Indiana, Danville, Illinois, and Baltimore, Maryland, USA were used. Four insecticide active ingredients (AIs) most used by consumers and PMPs were selected for testing in vial bioassays to establish resistance profiles. Next, no-choice and choice feeding assays with four currently registered bait products were performed to assess the impacts of competing food and circadian rhythms on bait resistance levels. The results indicate that emamectin benzoate (Optigard) was the most effective AI in causing the highest mortality in all strains in vial and no-choice bioassays; whereas, the other AIs and products were more impacted by resistance. The results acquired from these studies can help develop rapid tests for use by PMPs based on the no-choice feeding assay while also adding more information supporting current resistance and cross-resistance evolution theories.

Reactive Neutrophilic Dermatoses in Adult-Onset Immunodeficiency due to Interferon-Gamma Autoantibody and Their Associated Factors

Background: Adult-onset immunodeficiency (AOID) due to interferon-gamma autoantibody is a rare, acquired immunodeficiency disease. Reactive neutrophilic dermatoses (RND), predominantly Sweet syndrome (SS), and generalized pustular eruption have been reported repeatedly. Objectives: The aims of this study were to describe the cutaneous manifestations in AOID patients and determine the incidence of RND and associated factors using a larger population size than have been previously reported. Methods: A retrospective chart review of all confirmed AOID cases in Chiang Mai University Hospital from January 2006 to June 2020 was conducted. The demographics and characteristics of RND including type, onset, and laboratory information in every episode of cutaneous manifestations were collected. Generalized estimating equations of binary logistic regression were used to determine the indicators of RND. Results: A total of 146 patients with confirmed AOID were identified. Of these, 57 cases (39%) developed at least one episode of RND. Thirteen cases (23%) of the patients experienced RND twice during the follow-up period. All recurrence of RND displayed the same cutaneous phenotype, with the exception of 2 cases who had both SS and generalized pustular eruption. Finally, 49 episodes of SS and 22 episodes of generalized pustular eruption were included in the analysis. All patients with RND had concomitant active opportunistic infections, of which most were non-tuberculous mycobacterium (NTM) infection. NTM infection (prevalence odds ratio [POR] 2.87), lymphadenopathy (POR 3.30) as well as lower serum alkaline phosphatase (ALP) level (POR 0.71 for every 100-unit increment in ALP) were found to be significantly associated with RND occurrence. Conclusions: 39% of our AOID patients experienced RND once during the course of the disease. Notable factors associated with RND occurrence were concomitant NTM infection, lymphadenopathy, and lower level of ALP.

Stochastic drift in discrete waves of nonlocally interacting particles.

In this paper, we investigate a generalized model of N particles undergoing second-order nonlocal interactions on a lattice. Our results have applications across many research areas, including the modeling of migration, information dynamics, and Muller's ratchet-the irreversible accumulation of deleterious mutations in an evolving population. Strikingly, numerical simulations of the model are observed to deviate significantly from its mean-field approximation even for large population sizes. We show that the disagreement between deterministic and stochastic solutions stems from finite-size effects that change the propagation speed and cause the position of the wave to fluctuate. These effects are shown to decay anomalously as (lnN)^{-2} and (lnN)^{-3}, respectively-much slower than the usual N^{-1/2} factor. Our results suggest that the accumulation of deleterious mutations in a Muller's ratchet and the loss of awareness in a population may occur much faster than predicted by the corresponding deterministic models. The general applicability of our model suggests that this unexpected scaling could be important in a wide range of real-world applications.

Selecting for infectivity across metapopulations can increase virulence in the social microbe Bacillus thuringiensis.

Passage experiments that sequentially infect hosts with parasites have long been used to manipulate virulence. However, for many invertebrate pathogens, passage has been applied naively without a full theoretical understanding of how best to select for increased virulence and this has led to very mixed results. Understanding the evolution of virulence is complex because selection on parasites occurs across multiple spatial scales with potentially different conflicts operating on parasites with different life histories. For example, in social microbes, strong selection on replication rate within hosts can lead to cheating and loss of virulence, because investment in public goods virulence reduces replication rate. In this study, we tested how varying mutation supply and selection for infectivity or pathogen yield (population size in hosts) affected the evolution of virulence against resistant hosts in the specialist insect pathogen Bacillus thuringiensis, aiming to optimize methods for strain improvement against a difficult to kill insect target. We show that selection for infectivity using competition between subpopulations in a metapopulation prevents social cheating, acts to retain key virulence plasmids, and facilitates increased virulence. Increased virulence was associated with reduced efficiency of sporulation, and possible loss of function in putative regulatory genes but not with altered expression of the primary virulence factors. Selection in a metapopulation provides a broadly applicable tool for improving the efficacy of biocontrol agents. Moreover, a structured host population can facilitate artificial selection on infectivity, while selection on life-history traits such as faster replication or larger population sizes can reduce virulence in social microbes.