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Cheating is a focal concept in the study of mutualism, with the majority of researchers considering cheating to be both prevalent and highly damaging. However, current definitions of cheating do not reliably capture the evolutionary threat that has been a central motivation for the study of cheating. We describe the development of the cheating concept and distill a relative-fitness-based definition of cheating that encapsulates the evolutionary threat posed by cheating, i.e. that cheaters will spread and erode the benefits of mutualism. We then describe experiments required to conclude that cheating is occurring and to quantify fitness conflict more generally. Next, we discuss how our definition and methods can generate comparability and integration of theory and experiments, which are currently divided by their respective prioritisations of fitness consequences and traits. To evaluate the current empirical evidence for cheating, we review the literature on several of the best-studied mutualisms. We find that although there are numerous observations of low-quality partners, there is currently very little support from fitness data that any of these meet our criteria to be considered cheaters. Finally, we highlight future directions for research on conflict in mutualisms, including novel research avenues opened by a relative-fitness-based definition of cheating.

Background: Studies have suggested that acute myeloid leukemia (AML) patients with incomplete hematologic recovery undergoing allogeneic stem cell transplantation (allo‐HSCT) had inferior overall survival (OS). Study Design and Methods: This single‐center, retrospective study of AML patients evaluated the relationship between red blood cell (RBC) and platelet (PLT) transfusion requirements during the first 30 days and long‐term outcomes after allo‐HSCT through multivariate analyses. Results: A total of 692 AML patients received peripheral blood stem cells (89.2%), marrow (5.6%), or umbilical cord (5.2%) from matched related (37.4%), unrelated (49.1%), or haploidentical (8.2%) donors in 2011–2017. Transfusion requirements during the first 30 days for RBC (89.5% transfused, median 3, range 1–18 units) or PLT (98.2% transfused, median 6, range 1–144 units) were variable. By Day 30, 56.7% (95% confidence interval [CI]: 52.8–60.3%) and 86.1% (95% CI: 83.2–88.5%) had achieved RBC and PLT transfusion independence, respectively. Median follow‐up among survivors (n = 307) was 7.1 years (range: 2.7–11.8). Lack of RBC transfusion independence by Day 30 was strongly and independently associated with worse 5‐year OS (39.2% vs. 59.6%, adjusted hazard ratio [HR] 1.83, 95% CI: 1.49–2.25), leukemia‐free survival (35.8% vs. 55.5%, HR = 1.75, 95% CI: 1.43–2.14), and NRM (29.7% vs. 13.7%, HR = 2.05, 95% CI: 1.45–2.89) (p <.001). There was no difference in relapse rates among patients who achieved or did not achieve RBC (p =.34) or PLT (p =.64) transfusion independence. Conclusion: Prolonged RBC dependence predicted worse survival and NRM rates, but not increased relapse. Posttransplant surveillance of such patients should be adjusted with more attention to non‐relapse complications. [ABSTRACT FROM AUTHOR]

Objectives Determination of bone marrow cellularity is a key part of bone marrow examination because it provides a small window into a patient's current state of hematopoietic well-being. Traditionally, bone marrow cellularity is estimated semiquantitatively through microscopic examination of core biopsy specimens harvested from the iliac crest of the pelvic bone. Bone marrow cellularity is then designated as hypercellular, normocellular, or hypocellular based on the patient's age. This assessment can have significant clinical impact, but the variation in the age-adjusted normocellularity range is not sufficiently characterized because of a lack of study data, especially in older patients (those older than 70 years of age). This study further established the normal range of bone marrow cellularity, particularly in older adults. Methods In this study, 570 benign staging and healthy donor bone marrows from patients 1 year to 93 years of age were analyzed for cellularity. Results Linear regression modeling demonstrates that cellularity in adults declines approximately 3% per decade, including after the seventh decade of life. The 90% reference interval for normocellularity in United States is 30% to 75% for those aged 18 to 90 years. Conclusions The findings revealed a more stable and slower rate of decline in cellularity with age in adults than the widely used linear model of "100% minus the patient age in decades." Normocellularity is better modeled based on age group. In those younger than 20 years of age, normocellularity ranges from 45% to 85% (mean [SD], 65% [20%]), as defined by Friebert et al in 1998. Based on our study finding of a little less than 3% decline per decade of age, the following is our recommendation for normocellularity range: For individuals 20 to 40 years of age, it ranges from 40% to 70% (mean [SD], 55% [15%]); for individuals 40 to 60 years of age, it ranges from 35% to 65% (mean [SD], 50% [15%]); and for individuals older than 60 years of age, it ranges from 30% to 60% (mean [SD], 45% [15%]). Interestingly, those older than 70 years of age do not show a significant decrease from those aged 60 to 69 years. [ABSTRACT FROM AUTHOR]

The rate of MRD clearance in AML with standard consolidation chemotherapy is not well defined. A multi-institution retrospective analysis was performed on 107 consecutively treated AML patients in morphologic complete remission with detectable MRD post-induction therapy who received standard chemotherapy consolidation. In response to standard intermediate/high-dose cytarabine consolidation therapy, 26 of 60 patients (43.3%) with MRD threshold of detection of at least 0.1% converted to MRD-negative status (undetectable with assay used), and 6 of 47 patients (12.8%) with MRD threshold of detection > 0.1% converted to MRD-negative status. Multivariable logistic regression for patients with MRD threshold of detection of at least 0.1% showed that, when controlling for age, ELN risk category, dose of cytarabine, and use of a combination agent, treatment with 1 cycle of consolidation cytarabine versus ≥2 cycles decreased the odds of conversion of AML to MRD-negative (OR = 0.24, 95% CI 0.07–0.85, p = 0.03). [ABSTRACT FROM AUTHOR]

Summary: Allelopathy is a common and important stressor that shapes plant communities and can alter soil microbiomes, yet little is known about the direct effects of allelochemical addition on bacterial and fungal communities or the potential for allelochemical‐selected microbiomes to mediate plant performance responses, especially in habitats naturally structured by allelopathy.Here, we present the first community‐wide investigation of microbial mediation of allelochemical effects on plant performance by testing how allelopathy affects soil microbiome structure and how these microbial changes impact germination and productivity across 13 plant species.The soil microbiome exhibited significant changes to 'core' bacterial and fungal taxa, bacterial composition, abundance of functionally important bacterial and fungal taxa, and predicted bacterial functional genes after the addition of the dominant allelochemical native to this habitat. Furthermore, plant performance was mediated by the allelochemical‐selected microbiome, with allelopathic inhibition of plant productivity moderately mitigated by the microbiome.Through our findings, we present a potential framework to understand the strength of plant–microbial interactions in the presence of environmental stressors, in which frequency of the ecological stress may be a key predictor of microbiome‐mediation strength. [ABSTRACT FROM AUTHOR]