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1.
Article in English | MEDLINE | ID: mdl-38953004

ABSTRACT

On 12 September 2022, a 10-year-old female in Paracelis municipality, Mountain Province, the Philippines, without travel history outside the municipality, experienced acute onset of fever and a change in mental status with disorientation, an altered level of consciousness and new onset of seizures. She was hospitalized at the district hospital from 1 to 3 October 2022, before being transferred to the regional hospital. As diphtheria was originally suspected, the investigation team reviewed records and reports and interviewed key informants to gather additional information and organize case finding and contact tracing. The patient's condition was laboratory-confirmed for Japanese encephalitis virus infection. An environmental survey was carried out at the patient's residence to check for the presence of vectors and contributing factors. Exemplifying inadequate vaccination coverage for Japanese encephalitis virus in Mountain Province, the patient had not been vaccinated against the disease. It is recommended that vaccination campaigns be immediately implemented in the affected area and the surveillance system be strengthened for early detection and prompt response to the emergence of cases and outbreaks. Overall, the investigation highlighted the importance of strong surveillance and response systems for early detection and control of diseases, such as Japanese encephalitis virus. It also underscores the need for comprehensive vaccination programmes to prevent outbreaks and protect vulnerable populations.


Subject(s)
Encephalitis, Japanese , Humans , Philippines/epidemiology , Female , Encephalitis, Japanese/epidemiology , Encephalitis, Japanese/prevention & control , Child , Encephalitis Virus, Japanese/isolation & purification
2.
J Psychoactive Drugs ; : 1-12, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38961638

ABSTRACT

Sexualized drug use (SDU) describes drug-facilitated sexual enhancement, and chemsex is an SDU subculture involving the use of specific drugs by men who have sex with men (MSM). This study aimed to identify research trends, foci, and themes within the SDU and chemsex-specific literature. The Web of Science Core Collection was searched with a list of SDU synonyms. All SDU-related articles were analyzed using the R package, bibliometrix. Full text review identified chemsex-specific records, and text was extracted verbatim for content analysis in Leximancer. The search returned 1,866 unique records. A total of 521 addressed SDU, and 301 papers specifically addressed chemsex. The small but growing SDU literature primarily addressed consensual encounters between MSM, and drug-facilitated assault experienced by women, in Western settings. Little attention was given to transgender communities or consensual SDU in cisgender heterosexual individuals. The literature primarily viewed SDU through a public health lens, specifically focusing on the risk conferred to sexual health.The SDU and chemsex-specific literature are potentially limited in scope and may inadequately capture the geographical, demographic, and cultural diversity of these phenomena. Future research should address the myriad social and health implications of SDU and chemsex participation across all relevant communities and settings.

3.
Article in English | MEDLINE | ID: mdl-38990313

ABSTRACT

RATIONALE: Theories of addiction guide scientific progress, funding priorities, and policy development and ultimately shape how people experiencing or recovering from addiction are perceived and treated. Choice theories of addiction are heterogenous, and different models have divergent implications. This breeds confusion among laypeople, scientists, practitioners, and policymakers and reduces the utility of robust findings that have the potential to reduce the global burden of addiction-associated harms. OBJECTIVE: Here we differentiate classes of choice models and articulate a novel framing for a class of addiction models, called contextual models, which share as a first principle the influence of the environment and other contextual factors on behavior within discrete choice contexts. RESULTS: These models do not assume that all choice behaviors are voluntary, but instead that both proximal and distal characteristics of the choice environment-and particularly the benefits and costs of both drug use and non-drug alternatives-can influence behavior in ways that are outside of the awareness of the individual. From this perspective, addiction is neither the individual's moral failing nor an internal uncontrollable urge but rather is the result of environmental contingencies that reinforce the behavior. CONCLUSIONS: Contextual models have implications for guiding research, practice, and policy, including identification of novel target mechanisms while also improving existing interventions.

4.
Evolution ; 2024 Jul 12.
Article in English | MEDLINE | ID: mdl-38995057

ABSTRACT

Mitonuclear coevolution is common in eukaryotes, but bivalve lineages that have doubly uniparental inheritance (DUI) of mitochondria may be an interesting example. In this system, females transmit mtDNA (F mtDNA) to all offspring, while males transmit a different mtDNA (M mtDNA) solely to their sons. Molecular evolution and functional data suggest oxidative phosphorylation (OXPHOS) genes encoded in M mtDNA evolve under relaxed selection due to their function being limited to sperm only (vs. all other tissues for F mtDNA). This has led to the hypothesis that mitonuclear coevolution is less important for M mtDNA. Here, we use comparative phylogenetics, transcriptomics, and proteomics to understand mitonuclear interactions in DUI bivalves. We found nuclear OXPHOS proteins coevolve and maintain compatibility similarly with both F and M mtDNA OXPHOS proteins. Mitochondrial recombination did not influence mitonuclear compatibility and nuclear-encoded OXPHOS genes were not upregulated in tissues with M mtDNA to offset dysfunction. Our results support that selection maintains mitonuclear compatibility with F and M mtDNA despite relaxed selection on M mtDNA. Strict sperm transmission, lower effective population size, and higher mutation rates may explain the evolution of M mtDNA. Our study highlights that mitonuclear coevolution and compatibility may be broad features of eukaryotes.

6.
Soft Matter ; 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-39012310

ABSTRACT

The soft part of the Earth's surface - the ground beneath our feet - constitutes the basis for life and natural resources, yet a general physical understanding of the ground is still lacking. In this critical time of climate change, cross-pollination of scientific approaches is urgently needed to better understand the behavior of our planet's surface. The major topics in current research in this area cross different disciplines, spanning geosciences, and various aspects of engineering, material sciences, physics, chemistry, and biology. Among these, soft matter physics has emerged as a fundamental nexus connecting and underpinning many research questions. This perspective article is a multi-voice effort to bring together different views and approaches, questions and insights, from researchers that work in this emerging area, the soft matter physics of the ground beneath our feet. In particular, we identify four major challenges concerned with the dynamics in and of the ground: (I) modeling from the grain scale, (II) near-criticality, (III) bridging scales, and (IV) life. For each challenge, we present a selection of topics by individual authors, providing specific context, recent advances, and open questions. Through this, we seek to provide an overview of the opportunities for the broad Soft Matter community to contribute to the fundamental understanding of the physics of the ground, strive towards a common language, and encourage new collaborations across the broad spectrum of scientists interested in the matter of the Earth's surface.

7.
JNCI Cancer Spectr ; 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-39012500

ABSTRACT

BACKGROUND: The decline of physical function during chemotherapy predicts poor quality of life and premature death. It is unknown if resistance training prevents physical function decline during chemotherapy in colon cancer survivors. METHODS: This multicenter trial randomized 181 colon cancer survivors receiving postoperative chemotherapy to home-based resistance training or usual care control. Physical function outcomes included the short physical performance battery (SPPB), isometric handgrip strength, and the physical function subscale of the Medical Outcomes Short-Form 36-item questionnaire. Mixed models for repeated measures quantified estimated treatment differences (ETD). RESULTS: At baseline, subjects had a mean (SD) age of 55.2 years (12.8); 67 (37%) were ≥60 years, and 29 (16%) had a composite SPPB score ≤9. Compared with control, resistance training did not improve the composite SPPB score [ETD: -0.01 (95% CI: -0.32, 0.31); P = 0.98], or the SPPB scores for balance [ETD: 0.01 (95% CI: -0.10, 0.11); P = 0.93], gait speed [ETD: 0.08 (95% CI: -0.06, 0.22) P = 0.28], and sit-to-stand [ETD: -0.08 (95% CI: -0.29, 0.13); P = 0.46]. Compared with control, resistance training did not improve isometric handgrip strength [ETD: 1.50 kg (95% CI: -1.06, 4.05); P = 0.25] or self-reported physical function [ETD: -3.55 (95% CI: -10.03, 2.94); P = 0.28]. The baseline SPPB balance score [r=0.21 (95% CI: 0.07, 0.35)] and handgrip strength [r=0.23 (95% CI: 0.09, 0.36)] correlated with chemotherapy relative dose intensity. CONCLUSION: Among colon cancer survivors with relatively high physical functioning, randomization to home-based resistance training did not prevent physical function decline during chemotherapy. CLINICAL TRIAL REGISTRATION: NCT03291951.

9.
J Biomed Sci ; 31(1): 68, 2024 Jul 11.
Article in English | MEDLINE | ID: mdl-38992694

ABSTRACT

BACKGROUND: KRAS mutations frequently occur in cancers, particularly pancreatic ductal adenocarcinoma, colorectal cancer, and non-small cell lung cancer. Although KRASG12C inhibitors have recently been approved, effective precision therapies have not yet been established for all KRAS-mutant cancers. Many treatments for KRAS-mutant cancers, including epigenome-targeted drugs, are currently under investigation. Small ubiquitin-like modifier (SUMO) proteins are a family of small proteins covalently attached to and detached from other proteins in cells via the processes called SUMOylation and de-SUMOylation. We assessed whether SUMOylation inhibition was effective in KRAS-mutant cancer cells. METHODS: The efficacy of the first-in-class SUMO-activating enzyme E inhibitor TAK-981 (subasumstat) was assessed in multiple human and mouse KRAS-mutated cancer cell lines. A gene expression assay using a TaqMan array was used to identify biomarkers of TAK-981 efficacy. The biological roles of SUMOylation inhibition and subsequent regulatory mechanisms were investigated using immunoblot analysis, immunofluorescence assays, and mouse models. RESULTS: We discovered that TAK-981 downregulated the expression of the currently undruggable MYC and effectively suppressed the growth of MYC-expressing KRAS-mutant cancers across different tissue types. Moreover, TAK-981-resistant cells were sensitized to SUMOylation inhibition via MYC-overexpression. TAK-981 induced proteasomal degradation of MYC by altering the balance between SUMOylation and ubiquitination and promoting the binding of MYC and Fbxw7, a key factor in the ubiquitin-proteasome system. The efficacy of TAK-981 monotherapy in immunocompetent and immunodeficient mouse models using a mouse-derived CMT167 cell line was significant but modest. Since MAPK inhibition of the KRAS downstream pathway is crucial in KRAS-mutant cancer, we expected that co-inhibition of SUMOylation and MEK might be a good option. Surprisingly, combination treatment with TAK-981 and trametinib dramatically induced apoptosis in multiple cell lines and gene-engineered mouse-derived organoids. Moreover, combination therapy resulted in long-term tumor regression in mouse models using cell lines of different tissue types. Finally, we revealed that combination therapy complementally inhibited Rad51 and BRCA1 and accumulated DNA damage. CONCLUSIONS: We found that MYC downregulation occurred via SUMOylation inhibition in KRAS-mutant cancer cells. Our findings indicate that dual inhibition of SUMOylation and MEK may be a promising treatment for MYC-expressing KRAS-mutant cancers by enhancing DNA damage accumulation.


Subject(s)
DNA Damage , Proto-Oncogene Proteins p21(ras) , Sumoylation , Sumoylation/drug effects , Animals , Mice , Humans , Cell Line, Tumor , DNA Damage/drug effects , Proto-Oncogene Proteins p21(ras)/genetics , Proto-Oncogene Proteins p21(ras)/metabolism , Mutation , Proto-Oncogene Proteins c-myc/metabolism , Proto-Oncogene Proteins c-myc/genetics
10.
Am J Kidney Dis ; 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38958624
11.
Neurohospitalist ; 14(3): 363-365, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38895007

ABSTRACT

Herein we describe a case of relapsing anti-GAD65-associated encephalitis which was responsive to the combination of thymoma resection, external beam radiotherapy, and immunomodulatory therapy. The case illustrates the value of remaining vigilant for the possibility of paraneoplastic syndromes in the context of anti-GAD65 antibodies and thymoma. It also illustrates that tumor-directed therapies may offer additional benefit beyond immunomodulatory therapy alone.

12.
J Plast Reconstr Aesthet Surg ; 95: 319-330, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38945111

ABSTRACT

BACKGROUND: Soft tissue facial injuries (STFI) constitute a huge portion of craniofacial trauma, but the risk of surgical site infection (SSI) and patient-reported outcomes (PROs) following surgical management of STFI are unknown. METHODS: A PRISMA-compliant search was conducted from January 1990 until March 2023, and meta-analysis was performed using R. Pooled effects of the outcomes were estimated using the DerSimonian and Laird random-effects model or generalised linear mixed model, when feasible. RESULT: Among the 8897 screened studies, 38 were included. Twelve studies reported PROMs (n = 985), whereas 28 studies reported SSI rates (n = 10,996) following operative treatment for STFI. The pooled SSI rate (n = 28) was 3.30 % (95 % CI 1.89 %-5.71 %). Surgical and non-surgical closure did not differ significantly in SSI rate. PROs focused on scar outcomes, cosmetic outcomes, quality of life and psychological impact. Subgroup analysis showed lower SSI risk in operative repair for general facial trauma compared to primary repair, and in general facial trauma compared to other aetiologies. The pooled patient scar assessment scale, score at 6-12 months post-intervention (5 studies, n = 217) was 16.16 (95 % CI 15.34-16.97). Limited evidence is available on the effect and superiority of surgical treatment in cosmetic outcomes, quality of life and psychological impact. CONCLUSION: Our findings emphasise the limited and unreliable evidence available on PROs following operative treatment for STFI. Future studies employing robust methodologies are needed to investigate optimal approaches for managing STFI.

13.
Children (Basel) ; 11(6)2024 May 28.
Article in English | MEDLINE | ID: mdl-38929233

ABSTRACT

BACKGROUND: Pediatric colorectal specialists care for patients with a variety of defecation disorders. Anorectal (AR) manometry testing is a valuable tool in the diagnosis and management of these children. This paper provides a summary of AR manometry techniques and applications as well as a review of AR manometry findings in pediatric patients with severe defecation disorders referred to a pediatric colorectal center. This is the first study describing multi-year experience using a portable AR manometry device in pediatric patients. METHODS: An electronic medical record review was performed (1/2018 to 12/2023) of pediatric patients with defecation disorders who had AR manometry testing. Demographics, diagnostic findings, and outcomes are described. KEY RESULTS: A total of 297 unique patients (56.9% male, n = 169) had AR manometry testing. Of these, 72% (n = 188) had dyssynergic defecation patterns, of which 67.6% (n = 127) had fecal soiling prior to treatment. Pelvic rehabilitation (PR) was administered to 35.4% (n = 105) of all patients. A total of 79.5% (n = 58) of the 73 patients that had fecal soiling at initial presentation and completed PR with physical therapy and a bowel management program were continent after therapy. AR manometry was well tolerated, with no major complications. CONCLUSIONS: AR manometry is a simple test that can help guide the management of pediatric colorectal surgical patients with defecation disorders. As a secondary finding, PR is a useful treatment for patients with dyssynergic stooling.

14.
Pharmacol Biochem Behav ; 241: 173803, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38843997

ABSTRACT

Human laboratory models in substance use disorder provide a key intermediary step between highly controlled and mechanistically informative non-human preclinical methods and clinical trials conducted in human populations. Much like preclinical models, the variety of human laboratory methods provide insights into specific features of substance use disorder rather than modelling the diverse causes and consequences simultaneously in a single model. This narrative review provides a discussion of popular models of reward used in human laboratory research on substance use disorder with a focus on the specific contributions that each model has towards informing clinical outcomes (forward translation) and analogs within preclinical models (backward translation). Four core areas of human laboratory research are discussed: drug self-administration, subjective effects, behavioral economics, and cognitive and executive function. Discussion of common measures and models used, the features of substance use disorder that these methods are purported to evaluate, unique issues for measure validity and application, and translational links to preclinical models and special considerations for studies wishing to evaluate homology across species is provided.


Subject(s)
Reward , Self Administration , Substance-Related Disorders , Humans , Substance-Related Disorders/psychology , Animals , Executive Function , Cognition
15.
Mol Ther ; 2024 Jun 22.
Article in English | MEDLINE | ID: mdl-38910325

ABSTRACT

Extracellular vesicles (EVs) are considered a vital component of cell-to-cell communication and represent a new frontier in diagnostics and a means to identify pathways for therapeutic intervention. Recently, studies have revealed the importance of tissue-derived EVs (Ti-EVs), which are EVs present in the interstitial spaces between cells, as they better represent the underlying physiology of complex, multicellular tissue microenvironments in biology and disease. EVs are native, lipid bilayer membraned nano-sized particles produced by all cells that are packaged with varied functional biomolecules including proteins, lipids, and nucleic acids. They are implicated in short- and long-range cellular communication and may elicit functional responses in recipient cells. To date, studies have often utilized cultured cells or biological fluids as a source for EVs that do not capture local molecular signatures of the tissue microenvironment. Recent work utilizing Ti-EVs has elucidated novel biomarkers for disease and provided insights into disease mechanisms that may lead to the development of novel therapeutic agents. Still, there are considerable challenges facing current studies. This review explores the vast potential and unique challenges for Ti-EV research and provides considerations for future studies that seek to advance this exciting field.

16.
Pharmacol Biochem Behav ; 241: 173802, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38866372

ABSTRACT

The reinforcing efficacy, or behavior-strengthening effect, of a substance is a critical determinant of substance use typically quantified by measuring behavioral allocation to the substance under schedules of reinforcement with escalating response requirements. Although responses on these tasks are often used to indicate stable reinforcing effects or trait-level abuse potential for an individual, task designs often demonstrate within-person variability across varying degrees of a constraint within experimental procedures. As a result, quantifying behavioral allocation is an effective approach for measuring the impact of contextual and psychosocial factors on substance reward. We review studies using laboratory self-administration, behavioral economic purchase tasks, and ambulatory assessments to quantify the impact of various contextual and psychosocial factors on behavioral allocation toward consumption of a substance. We selected these assessment approaches because they cover the translational spectrum from experimental control to ecological relevance, with consistent support across these approaches representing greater confidence in the effect. Conceptually, we organized factors that influence substance value into two broad categories: factors that influence the cost/benefit ratio of the substance (social context, stress and affect, cue exposure), and factors that influence the cost/benefit ratio of an alternative (alternative non-drug reinforcers, alternative drug reinforcers, and opportunity costs). We conclude with an overview of future research directions and considerations for clinical application.


Subject(s)
Reinforcement, Psychology , Reward , Substance-Related Disorders , Humans , Substance-Related Disorders/psychology , Self Administration , Cues , Cost-Benefit Analysis
17.
Nat Med ; 2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38871975

ABSTRACT

Microsatellite stable metastatic colorectal cancer (MSS mCRC; mismatch repair proficient) has previously responded poorly to immune checkpoint blockade. Botensilimab (BOT) is an Fc-enhanced multifunctional anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody designed to expand therapy to cold/poorly immunogenic solid tumors, such as MSS mCRC. BOT with or without balstilimab (BAL; anti-PD-1 antibody) is being evaluated in an ongoing expanded phase 1 study. The primary endpoint is safety and tolerability, which was evaluated separately in the dose-escalation portion of the study and in patients with MSS mCRC (using combined dose-escalation/dose-expansion data). Secondary endpoints include investigator-assessed RECIST version 1.1-confirmed objective response rate (ORR), disease control rate (DCR), duration of response (DOR) and progression-free survival (PFS). Here we present outcomes in 148 heavily pre-treated patients with MSS mCRC (six from the dose-escalation cohort; 142 from the dose-expansion cohort) treated with BOT and BAL, 101 of whom were considered response evaluable with at least 6 months of follow-up. Treatment-related adverse events (TRAEs) occurred in 89% of patients with MSS mCRC (131/148), most commonly fatigue (35%, 52/148), diarrhea (32%, 47/148) and pyrexia (24%, 36/148), with no grade 5 TRAEs reported and a 12% discontinuation rate due to a TRAE (18/148; data fully mature). In the response-evaluable population (n = 101), ORR was 17% (17/101; 95% confidence interval (CI), 10-26%), and DCR was 61% (62/101; 95% CI, 51-71%). Median DOR was not reached (NR; 95% CI, 5.7 months-NR), and median PFS was 3.5 months (95% CI, 2.7-4.1 months), at a median follow-up of 10.3 months (range, 0.5-42.6 months; data continuing to mature). The combination of BOT plus BAL demonstrated a manageable safety profile with no new immune-mediated safety signals and encouraging clinical activity with durable responses. ClinicalTrials.gov identifier: NCT03860272 .

18.
Plast Reconstr Surg Glob Open ; 12(6): e5885, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38881966

ABSTRACT

Background: Raynaud disease of the hands is a complex disorder resulting in inappropriate constriction and/or insufficient dilation in microcirculation. There is an emerging role for botulinum toxin type A (BTX-A) in the treatment armamentarium for refractory Raynaud disease. The aim of this systematic review was to critically evaluate the management of primary and secondary Raynaud disease treated with BTX-A intervention. Methods: We performed a Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review of clinical studies assessing treatment of primary or secondary Raynaud disease with BTX-A by searching Ovid MEDLINE and Embase databases from inception to first August 2023. The review protocol was prospectively registered on the PROSPERO database (CRD42022312253). Results: Our search strategy identified 288 research articles, of which 18 studies [four randomized controlled trials (RCTs), two non-RCTs, five case series, and seven retrospective cohort studies] were eligible for analysis. Meta-analysis demonstrated that the probability of pain visual analog scale score improvement with BTX-A intervention was 81.95% [95% confidence interval (74.12-87.81) P = 0.19, heterogeneity I 2 = 26%] and probability of digital ulcer healing was 79.37% [95% confidence interval (62.45-89.9) P = 0.02, heterogeneity I 2 = 56%]. Conclusions: Delivery of BTX-A to digital vessels in the hand may be an effective management strategy for primary and secondary Raynaud disease. A definitive, appropriately-powered RCT with objective functional and patient-reported outcome measures is required to accurately assess and quantify the efficacy of BTX-A in Raynaud disease of the hands.

19.
Article in English | MEDLINE | ID: mdl-38887915

ABSTRACT

BACKGROUND: Physical activity and metformin pharmacotherapy are associated with improved clinical outcomes in breast and colorectal cancer survivors. Myokines are cytokines secreted from skeletal muscle that may mediate these associations. METHODS: This hypothesis-generating analysis used biospecimens collected from a multi-centre 2 × 2 factorial randomized design of 116 patients with stage I-III breast and colorectal cancer who were randomized to 12 weeks of (1) aerobic exercise (moderate intensity titrated to 220 min/week); (2) metformin (850 mg daily for 2 weeks and then titrated to 850 mg twice per day); (3) aerobic exercise and metformin; or (4) control. Fourteen myokines were quantified using a multiplex panel. Myokine concentrations were log-transformed, and main effects analyses were conducted using linear mixed-effects regression models. The type I error rate was controlled with the Holm sequential testing procedure. RESULTS: Randomization to exercise increased leukaemia inhibitory factor (1.26 pg/mL, 95% confidence interval [CI]: 0.69, 1.84; adjusted P = 0.001) and interleukin-15 (2.23 pg/mL, 95% CI: 0.87, 3.60; adjusted P = 0.013) compared with randomization to no exercise. Randomization to metformin decreased apelin (-2.69 pg/mL, 95% CI: -4.31, -1.07; adjusted P = 0.014) and interleukin-15 (-1.74 pg/mL, 95% CI: -2.79, -0.69; adjusted P = 0.013) compared with randomization to no metformin. Metformin decreased myostatin, irisin, oncostatin M, fibroblast growth factor 21 and osteocrin; however, these changes were not statistically significant after correction for multiple comparisons. CONCLUSIONS: This pilot study demonstrates that randomization to exercise and metformin elicit unique effects on myokine concentrations in cancer patients. This hypothesis-generating observation warrants further basic, translational and clinical investigation and replication.

20.
bioRxiv ; 2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38895255

ABSTRACT

Domesticated strains of Saccharomyces cerevisiae have adapted to resist copper and sulfite, two chemical stressors commonly used in winemaking. S. paradoxus, has not adapted to these chemicals despite being consistently present in sympatry with S. cerevisiae in vineyards. This contrast represents a case of apparent evolutionary constraints favoring greater adaptive capacity in S. cerevisiae. In this study, we used a comparative mutagenesis approach to test whether S. paradoxus is mutationally constrained with respect to acquiring greater copper and sulfite resistance. For both species, we assayed the rate, effect size, and pleiotropic costs of resistance mutations and sequenced a subset of 150 mutants isolated from our screen. We found that the distributions of mutational effects displayed by the two species were very similar and poorly explained the natural pattern. We also found that chromosome VIII aneuploidy and loss of function mutations in PMA1 confer copper resistance in both species, whereas loss of function mutations in REG1 were only a viable route to copper resistance in S. cerevisiae. We also observed a single de novo duplication of the CUP1 gene in S. paradoxus but none in S. cerevisiae. For sulfite, loss of function mutations in RTS1 and KSP1 confer resistance in both species, but mutations in RTS1 have larger average effects in S. paradoxus. Our results show that even when the distributions of mutational effects are largely similar, species can differ in the adaptive paths available to them. They also demonstrate that assays of the distribution of mutational effects may lack predictive insight concerning adaptive outcomes.

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