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1.
Front Nutr ; 11: 1366883, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38571752

RESUMO

Objective: Obesity and metabolic complications, such as type 2 diabetes and nonalcoholic fatty liver disease (NAFLD), are one of the greatest public health challenges of the 21st century. The major role of high sugar and carbohydrate consumption rather than caloric intake in obesity and NAFLD pathophysiology remains a subject of debate. A low-carbohydrate but high-fat diet (LCHFD) has shown promising results in obesity management, but its effects in preventing NAFLD need to be detailed. This study aims to compare the effects of a LCHFD with a high-fat high-sugar obesogenic Western diet (WD) on the progression of obesity, type 2 diabetes, and nonalcoholic fatty liver disease. Methods: Male C57BL/6J mice were initially fed a WD for 10 weeks. Subsequently, they were either switched to a LCHFD or maintained on the WD for an additional 6 weeks. Hepatic effects of the diet were explored by histological staining and RT-qPCR. Results: After the initial 10 weeks WD feeding, LCHF diet demonstrated effectiveness in halting weight gain, maintaining a normal glucose tolerance and insulin levels, in comparison to the WD-fed mice, which developed obesity, glucose intolerance, increased insulin levels and induced NAFLD. In the liver, LCHFD mitigated the accumulation of hepatic triglycerides and the increase in Fasn relative gene expression compared to the WD mice. Beneficial effects of the LCHFD occurred despite a similar calorie intake compared to the WD mice. Conclusion: Our results emphasize the negative impact of a high sugar/carbohydrate and lipid association for obesity progression and NAFLD development. LCHFD has shown beneficial effects for NAFLD management, notably improving weight management, and maintaining a normal glucose tolerance and liver health.

3.
Nat Commun ; 15(1): 2713, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38548728

RESUMO

DNA methylation is an ideal trait to study the extent of the shared genetic control across ancestries, effectively providing hundreds of thousands of model molecular traits with large QTL effect sizes. We investigate cis DNAm QTLs in three European (n = 3701) and two East Asian (n = 2099) cohorts to quantify the similarities and differences in the genetic architecture across populations. We observe 80,394 associated mQTLs (62.2% of DNAm probes with significant mQTL) to be significant in both ancestries, while 28,925 mQTLs (22.4%) are identified in only a single ancestry. mQTL effect sizes are highly conserved across populations, with differences in mQTL discovery likely due to differences in allele frequency of associated variants and differing linkage disequilibrium between causal variants and assayed SNPs. This study highlights the overall similarity of genetic control across ancestries and the value of ancestral diversity in increasing the power to detect associations and enhancing fine mapping resolution.


Assuntos
Metilação de DNA , População do Leste Asiático , Humanos , Metilação de DNA/genética , Locos de Características Quantitativas/genética , Regulação da Expressão Gênica , Desequilíbrio de Ligação , Polimorfismo de Nucleotídeo Único , Estudo de Associação Genômica Ampla
4.
Anesth Analg ; 138(2): 358-368, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38215714

RESUMO

Social media has rapidly developed in the past decade to become a powerful and influential force for patients, physicians, health systems, and the academic community. While the use of social media in health care has produced many positive changes, such as rapid dissemination of information, crowd-sourced sharing of knowledge, learning, and social interaction, social media in health care has also negative effects. Recent examples of negative impacts of social media include rapid and unchecked information dissemination leading to patient misinformation and inadvertent reputational harm for health care professionals due to engaging in controversial topics on public platforms. Members of the anesthesiology community, like other medical specialties, have rapidly adopted social media at many different levels. However, most anesthesiologists, health systems, and academic communities have little education, preparation, and guidelines on optimizing the use of social media technology while minimizing the risks of social media. Anesthesiology has been and will continue to be impacted by the forces of technology and the cultural influences of social media for the foreseeable future. The purpose of this article was to examine the recent history of social media adoption in anesthesiology and perioperative medicine, understand the current impact of social media across our specialty, and consider how the future development of technology and evolving social and cultural dynamic influences of social media will have on anesthesiology over the next quarter century.


Assuntos
Anestesiologia , Médicos , Mídias Sociais , Humanos , Anestesiologia/educação , Anestesiologistas , Pessoal de Saúde
6.
J Cachexia Sarcopenia Muscle ; 15(1): 292-305, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38183352

RESUMO

BACKGROUND: Breast cancer patients are commonly treated with sequential administrations of epirubicin-cyclophosphamide (EC) and paclitaxel (TAX). The chronic effect of this treatment induces skeletal muscle alterations, but the specific effect of each chemotherapy agent is unknown. This study aimed to investigate the effect of EC or TAX administration on skeletal muscle homeostasis in breast cancer patients. METHODS: Twenty early breast cancer patients undergoing EC followed by TAX chemotherapies were included. Two groups of 10 women were established and performed vastus lateralis skeletal muscle biopsies either before the first administration (pre) of EC (50 ± 14 years) or TAX (50 ± 16 years) and 4 days later (post). Mitochondrial respiratory capacity recording, reactive oxygen species production, western blotting and histological analyses were performed. RESULTS: Decrease in muscle fibres cross-sectional area was only observed post-EC (-25%; P < 0.001), associated with a reduction in mitochondrial respiratory capacity for the complex I (CI)-linked substrate state (-32%; P = 0.001), oxidative phosphorylation (OXPHOS) by CI (-35%; P = 0.002), CI&CII (-26%; P = 0.022) and CII (-24%; P = 0.027). If H2 O2 production was unchanged post-EC, an increase was observed post-TAX for OXPHOS by CII (+25%; P = 0.022). We found a decrease in makers of mitochondrial content, as shown post-EC by a decrease in the protein levels of citrate synthase (-53%; P < 0.001) and VDAC (-39%; P < 0.001). Despite no changes in markers of mitochondrial fission, a decrease in the expression of a marker of mitochondrial inner-membrane fusion was found post-EC (OPA1; -60%; P < 0.001). We explored markers of mitophagy and found reductions post-EC in the protein levels of PINK1 (-63%; P < 0.001) and Parkin (-56%; P = 0.005), without changes post-TAX. An increasing trend in Bax protein level was found post-EC (+96%; P = 0.068) and post-TAX (+77%; P = 0.073), while the Bcl-2 level was decreased only post-EC (-52%; P = 0.007). If an increasing trend in TUNEL-positive signal was observed post-EC (+68%; P = 0.082), upregulation was highlighted post-TAX (+86%; P < 0.001), suggesting activation of the apoptosis process. CONCLUSIONS: We demonstrated that a single administration of EC induced, in only 4 days, skeletal muscle atrophy and mitochondrial alterations in breast cancer patients. These alterations were characterized by reductions in mitochondrial function and content as well as impairment of mitochondrial dynamics and an increase in apoptosis. TAX administration did not worsen these alterations as this group had already received EC during the preceding weeks. However, it resulted in an increased apoptosis, likely in response to the increased H2 O2 production.


Assuntos
Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/metabolismo , Mitocôndrias/metabolismo , Músculo Esquelético/patologia , Atrofia Muscular/patologia , Complexo I de Transporte de Elétrons/metabolismo , Apoptose
7.
Paediatr Anaesth ; 34(3): 267-273, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38069629

RESUMO

INTRODUCTION: Micrognathic neonates are at risk for upper airway obstruction, and many require intubation in the delivery room. Ex-utero intrapartum treatment is one technique for managing airway obstruction but poses substantial maternal risks. Procedure requiring a second team in the operating room is an alternative approach to secure the obstructed airway while minimizing maternal risk. The aim of this study was to describe the patient characteristics, airway management, and outcomes for micrognathic neonates and their mothers undergoing a procedure requiring a second team in the operating room at a single quaternary care children's hospital. METHODS: This was a retrospective descriptive study. Subjects had prenatally diagnosed micrognathia and underwent procedure requiring a second team in the operating room between 2009 and 2021. Collected data included infant characteristics, delivery room airway management, critical events, and medications. Follow-up data included genetic testing and subsequent procedures within 90 days. Maternal data included type of anesthetic, blood loss, and incidence of transfusion. RESULTS: Fourteen deliveries were performed via procedure requiring a second team in the operating room during the study period. 85.7% were male, and 50% had a genetic syndrome. Spontaneous respiratory efforts were observed in 93%. Twelve patients (85.7%) required an endotracheal tube or tracheostomy. Management approaches varied. Medications were primarily a combination of atropine, ketamine, and dexmedetomidine. Oxygen desaturation was common, and three patients experienced bradycardia. There were no periprocedural deaths. Follow-up at 90 days revealed that 78% of patients underwent at least one additional procedure, and one patient died due to an unrelated cause. All mothers underwent cesarean deliveries under neuraxial anesthesia. Median blood loss was 700 mL [IQR 700 mL, 800 mL]. Only one mother required a blood transfusion for pre-procedural placental abruption. DISCUSSION: Procedure requiring a second team in the operating room is a safe and effective approach to manage airway obstruction in micrognathic neonates while minimizing maternal morbidity. CONCLUSIONS: Though shown to be safe and effective, more data are needed to support the use of procedure requiring a second team in the operating room as an alternative to ex-utero intrapartum treatment for micrognathia outside of highly specialized maternal-fetal centers.


Assuntos
Obstrução das Vias Respiratórias , Micrognatismo , Recém-Nascido , Lactente , Criança , Humanos , Masculino , Feminino , Gravidez , Micrognatismo/complicações , Estudos Retrospectivos , Placenta , Manuseio das Vias Aéreas/métodos , Obstrução das Vias Respiratórias/terapia
8.
Resuscitation ; 194: 110049, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37972682

RESUMO

AIM OF THE REVIEW: The primary aim of this systematic review was to investigate the most common electroencephalogram (EEG)-based machine learning (ML) model with the highest Area Under Receiver Operating Characteristic Curve (AUC) in two ML categories, conventional ML and Deep Neural Network (DNN), to predict the neurologic outcomes after cardiac arrest; the secondary aim was to investigate common EEG features applied to ML models. METHODS: Systematic search of medical literature from PubMed and engineering literature from Compendex up to June 2, 2023. One reviewer screened studies that used EEG-based ML models to predict the neurologic outcomes after cardiac arrest. Four reviewers validated that the studies met selection criteria. Nine variables were manually extracted. The top-five common EEG features were calculated. We evaluated each study's risk of bias using the Quality in Prognosis Studies guideline. RESULTS: Out of 351 identified studies, 17 studies met the inclusion criteria. Random Forest (RF) (n = 7) was the most common ML model in the conventional ML category (n = 11), followed by Convolutional Neural Network (CNN) (n = 4) in the DNN category (n = 6). The AUCs for RF ranged between 0.8 and 0.97, while CNN had AUCs between 0.7 and 0.92. The top-three commonly used EEG features were band power (n = 12), Shannon's Entropy (n = 11), burst-suppression ratio (n = 9). CONCLUSIONS: RF and CNN were the two most common ML models with the highest AUCs for predicting the neurologic outcomes after cardiac arrest. Using a multimodal model that combines EEG features and electronic health record data may further improve prognostic performance.


Assuntos
Parada Cardíaca , Humanos , Parada Cardíaca/terapia , Parada Cardíaca/complicações , Aprendizado de Máquina , Prognóstico , Eletroencefalografia , Curva ROC
9.
Paediatr Anaesth ; 34(4): 354-365, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38146211

RESUMO

INTRODUCTION: Neonates have a high incidence of respiratory and cardiac perioperative events. Disease severity and indications for surgical intervention often dovetail with an overall complex clinical course and predispose these infants to adverse long-term neurodevelopmental outcomes and increased length of stay. Our aims were to describe severe and nonsevere early postoperative complications to establish a baseline of care outcomes and to identify subgroups of surgical neonates and procedures for future prospective studies. METHODS: Electronic health record data were examined retrospectively for a cohort of patients who had general anesthesia from January 26, 2015 to August 31, 2018. Inclusion criteria were full-term infants with postmenstrual age less than 44 weeks or premature infants less than 60 weeks postmenstrual age undergoing nonimaging, noncardiac surgery. Severe postoperative complications were defined as mortality, reintubation, positive blood culture, and surgical site infection. Nonsevere early postoperative outcomes were defined as hypoglycemia, hyperglycemia, hypothermia, hyperthermia, and readmission within 30 days. RESULTS: About 2569 procedures were performed in 1842 neonates of which 10.9% were emergency surgeries. There were 120 postoperative severe complications and 965 nonsevere postoperative outcomes. Overall, 30-day mortality was 1.8% for the first procedure performed, with higher mortality seen on subgroup analysis for patients who underwent exploratory laparotomy (10.3%) and congenital lung lesion resection (4.9%). Postoperative areas for improvement included hyperglycemia (13.9%) and hypothermia (7.9%). DISCUSSION: The mortality rate in our study was comparable to other studies of neonatal surgery despite a high rate of emergency surgery and a high prevalence of prematurity in our cohort. The early outcomes data identified areas for improvement, including prevention of postoperative glucose and temperature derangements. CONCLUSIONS: Neonates in this cohort were at risk for severe and nonsevere adverse postoperative outcomes. Future studies are suggested to improve mortality and adverse event rates.


Assuntos
Hiperglicemia , Hipotermia , Recém-Nascido , Lactente , Criança , Humanos , Estudos Retrospectivos , Estudos Prospectivos , Complicações Pós-Operatórias/epidemiologia , Hospitais
10.
Genome Biol ; 24(1): 278, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38053194

RESUMO

BACKGROUND: Epigenetic scores (EpiScores) can provide biomarkers of lifestyle and disease risk. Projecting new datasets onto a reference panel is challenging due to separation of technical and biological variation with array data. Normalisation can standardise data distributions but may also remove population-level biological variation. RESULTS: We compare two birth cohorts (Lothian Birth Cohorts of 1921 and 1936 - nLBC1921 = 387 and nLBC1936 = 498) with blood-based DNA methylation assessed at the same chronological age (79 years) and processed in the same lab but in different years and experimental batches. We examine the effect of 16 normalisation methods on a novel BMI EpiScore (trained in an external cohort, n = 18,413), and Horvath's pan-tissue DNA methylation age, when the cohorts are normalised separately and together. The BMI EpiScore explains a maximum variance of R2=24.5% in BMI in LBC1936 (SWAN normalisation). Although there are cross-cohort R2 differences, the normalisation method makes a minimal difference to within-cohort estimates. Conversely, a range of absolute differences are seen for individual-level EpiScore estimates for BMI and age when cohorts are normalised separately versus together. While within-array methods result in identical EpiScores whether a cohort is normalised on its own or together with the second dataset, a range of differences is observed for between-array methods. CONCLUSIONS: Normalisation methods returning similar EpiScores, whether cohorts are analysed separately or together, will minimise technical variation when projecting new data onto a reference panel. These methods are important for cases where raw data is unavailable and joint normalisation of cohorts is computationally expensive.


Assuntos
Metilação de DNA , Epigenômica , Humanos , Idoso , Biomarcadores , Epigênese Genética
11.
JAMIA Open ; 6(4): ooad106, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38098478

RESUMO

Objectives: Pediatric emergence delirium is an undesirable outcome that is understudied. Development of a predictive model is an initial step toward reducing its occurrence. This study aimed to apply machine learning (ML) methods to a large clinical dataset to develop a predictive model for pediatric emergence delirium. Materials and Methods: We performed a single-center retrospective cohort study using electronic health record data from February 2015 to December 2019. We built and evaluated 4 commonly used ML models for predicting emergence delirium: least absolute shrinkage and selection operator, ridge regression, random forest, and extreme gradient boosting. The primary outcome was the occurrence of emergence delirium, defined as a Watcha score of 3 or 4 recorded at any time during recovery. Results: The dataset included 54 776 encounters across 43 830 patients. The 4 ML models performed similarly with performance assessed by the area under the receiver operating characteristic curves ranging from 0.74 to 0.75. Notable variables associated with increased risk included adenoidectomy with or without tonsillectomy, decreasing age, midazolam premedication, and ondansetron administration, while intravenous induction and ketorolac were associated with reduced risk of emergence delirium. Conclusions: Four different ML models demonstrated similar performance in predicting postoperative emergence delirium using a large pediatric dataset. The prediction performance of the models draws attention to our incomplete understanding of this phenomenon based on the studied variables. The results from our modeling could serve as a first step in designing a predictive clinical decision support system, but further optimization and validation are needed. Clinical trial number and registry URL: Not applicable.

12.
Cell Genom ; 3(12): 100457, 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38116117

RESUMO

Complement components have been linked to schizophrenia and autoimmune disorders. We examined the association between neonatal circulating C3 and C4 protein concentrations in 68,768 neonates and the risk of six mental disorders. We completed genome-wide association studies (GWASs) for C3 and C4 and applied the summary statistics in Mendelian randomization and phenome-wide association studies related to mental and autoimmune disorders. The GWASs for C3 and C4 protein concentrations identified 15 and 36 independent loci, respectively. We found no associations between neonatal C3 and C4 concentrations and mental disorders in the total sample (both sexes combined); however, post-hoc analyses found that a higher C3 concentration was associated with a reduced risk of schizophrenia in females. Mendelian randomization based on C4 summary statistics found an altered risk of five types of autoimmune disorders. Our study adds to our understanding of the associations between C3 and C4 concentrations and subsequent mental and autoimmune disorders.

13.
BJA Open ; 8: 100234, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37942056

RESUMO

The coronavirus pandemic has raised public awareness of one of the many hazards that healthcare workers face daily: exposure to harmful pathogens. The anaesthesia workplace encompasses the operating room, interventional radiology suite, and other sites that contain many other potential occupational and environmental hazards. This review article highlights the work-based hazards that anaesthesiologists and other clinicians may encounter in the anaesthesia workplace: ergonomic design, physical, chemical, fire, biological, or psychological hazards. As the anaesthesia work environment enters a post-COVID-19 pandemic phase, anaesthesiologists will do well to review and consider these hazards. The current review includes proposed solutions to some hazards and identifies opportunities for future research.

15.
Emerg Infect Dis ; 29(10): 2155-2158, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37735786

RESUMO

Slaughterhouses are hotspots for the transmission of antimicrobial-resistant pathogens. We conducted stakeholder discussions on antimicrobial-resistant pathogens within the slaughterhouse setting. Butchers were described as powerful stakeholders; challenges included limited funding and staff, inadequate infrastructure, and limited laboratory capacity. Slaughterhouse workers understood that their work increased their risk for exposure.


Assuntos
Matadouros , Antibacterianos , Humanos , Quênia/epidemiologia , Farmacorresistência Bacteriana , Laboratórios
16.
Commun Biol ; 6(1): 780, 2023 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-37587191

RESUMO

Endometriosis is a leading cause of pain and infertility affecting millions of women globally. Herein, we characterize variation in DNA methylation (DNAm) and its association with menstrual cycle phase, endometriosis, and genetic variants through analysis of genotype data and methylation in endometrial samples from 984 deeply-phenotyped participants. We estimate that 15.4% of the variation in endometriosis is captured by DNAm and identify significant differences in DNAm profiles associated with stage III/IV endometriosis, endometriosis sub-phenotypes and menstrual cycle phase, including opening of the window for embryo implantation. Menstrual cycle phase was a major source of DNAm variation suggesting cellular and hormonally-driven changes across the cycle can regulate genes and pathways responsible for endometrial physiology and function. DNAm quantitative trait locus (mQTL) analysis identified 118,185 independent cis-mQTLs including 51 associated with risk of endometriosis, highlighting candidate genes contributing to disease risk. Our work provides functional evidence for epigenetic targets contributing to endometriosis risk and pathogenesis. Data generated serve as a valuable resource for understanding tissue-specific effects of methylation on endometrial biology in health and disease.


Assuntos
Endometriose , Feminino , Humanos , Endometriose/genética , Metilação de DNA , Dor , Implantação do Embrião
17.
Am J Hum Genet ; 110(9): 1564-1573, 2023 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-37652023

RESUMO

The recent increase in obesity levels across many countries is likely to be driven by nongenetic factors. The epigenetic modification DNA methylation (DNAm) may help to explore this, as it is sensitive to both genetic and environmental exposures. While the relationship between DNAm and body-fat traits has been extensively studied, there is limited literature on the shared associations of DNAm variation across such traits. Akin to genetic correlation estimates, here, we introduce an approach to evaluate the similarities in DNAm associations between traits: DNAm correlations. As DNAm can be both a cause and consequence of complex traits, DNAm correlations have the potential to provide insights into trait relationships above that currently obtained from genetic and phenotypic correlations. Utilizing 7,519 unrelated individuals from Generation Scotland with DNAm from the EPIC array, we calculated DNAm correlations between body-fat- and adiposity-related traits by using the bivariate OREML framework in the OSCA software. For each trait, we also estimated the shared contribution of DNAm between sexes. We identified strong, positive DNAm correlations between each of the body-fat traits (BMI, body-fat percentage, and waist-to-hip ratio, ranging from 0.96 to 1.00), finding larger associations than those identified by genetic and phenotypic correlations. We identified a significant deviation from 1 in the DNAm correlations for BMI between males and females, with sex-specific DNAm changes associated with BMI identified at eight DNAm probes. Employing genome-wide DNAm correlations to evaluate the similarities in the associations of DNAm with complex traits has provided insight into obesity-related traits beyond that provided by genetic correlations.


Assuntos
Adiposidade , Metilação de DNA , Feminino , Masculino , Humanos , Metilação de DNA/genética , Adiposidade/genética , Obesidade/genética , Tecido Adiposo , Epigênese Genética
18.
Anesthesiology ; 139(4): 393-404, 2023 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-37440275

RESUMO

BACKGROUND: Children undergoing complex cardiac surgery are exposed to substantial cumulative doses of sedative medications and volatile anesthetics and are more frequently anesthetized with ketamine, compared with healthy children. This study hypothesized that greater exposure to sedation and anesthesia in this population is associated with lower neurodevelopmental scores at 18 months of age. METHODS: A secondary analysis was conducted of infants with congenital heart disease who participated in a prospective observational study of environmental exposures and neurodevelopmental outcomes to assess the impact of cumulative volatile anesthetic agents and sedative medications. Cumulative minimum alveolar concentration hours of exposure to volatile anesthetic agents and all operating room and intensive care unit exposures to sedative and anesthesia medications were collected before administration of Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley III), at 18 months of age. RESULTS: The study cohort included 41 (37%) single-ventricle and 69 (63%) two-ventricle patients. Exposures to volatile anesthetic agents, opioids, benzodiazepines, and dexmedetomidine were not associated with abnormal Bayley III scores. At 18-month follow-up, after adjusting for confounders, each mg/kg increase in ketamine exposure was associated with a 0.34 (95% CI, -0.64 to -0.05) point decrease in Bayley III motor scores (P = 0.024). CONCLUSIONS: Total cumulative exposures to volatile anesthetic agents were not associated with neurodevelopmental impairment in infants with congenital heart disease undergoing various imaging studies and procedures, whereas higher ketamine doses were associated with poorer motor performance.


Assuntos
Anestesia , Anestésicos , Procedimentos Cirúrgicos Cardíacos , Cardiopatias Congênitas , Ketamina , Humanos , Lactente , Estudos Retrospectivos , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Cardiopatias Congênitas/cirurgia , Hipnóticos e Sedativos/efeitos adversos
20.
Pathogens ; 12(6)2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37375510

RESUMO

Fusarium wilt of banana is a devastating disease that has decimated banana production worldwide. Host resistance to Fusarium oxysporum f. sp. Cubense (Foc), the causal agent of this disease, is genetically dissected in this study using two Musa acuminata ssp. Malaccensis segregating populations, segregating for Foc Tropical (TR4) and Subtropical (STR4) race 4 resistance. Marker loci and trait association using 11 SNP-based PCR markers allowed the candidate region to be delimited to a 12.9 cM genetic interval corresponding to a 959 kb region on chromosome 3 of 'DH-Pahang' reference assembly v4. Within this region, there was a cluster of pattern recognition receptors, namely leucine-rich repeat ectodomain containing receptor-like protein kinases, cysteine-rich cell-wall-associated protein kinases, and leaf rust 10 disease-resistance locus receptor-like proteins, positioned in an interspersed arrangement. Their transcript levels were rapidly upregulated in the resistant progenies but not in the susceptible F2 progenies at the onset of infection. This suggests that one or several of these genes may control resistance at this locus. To confirm the segregation of single-gene resistance, we generated an inter-cross between the resistant parent 'Ma850' and a susceptible line 'Ma848', to show that the STR4 resistance co-segregated with marker '28820' at this locus. Finally, an informative SNP marker 29730 allowed the locus-specific resistance to be assessed in a collection of diploid and polyploid banana plants. Of the 60 lines screened, 22 lines were predicted to carry resistance at this locus, including lines known to be TR4-resistant, such as 'Pahang', 'SH-3362', 'SH-3217', 'Ma-ITC0250', and 'DH-Pahang/CIRAD 930'. Additional screening in the International Institute for Tropical Agriculture's collection suggests that the dominant allele is common among the elite 'Matooke' NARITA hybrids, as well as in other triploid or tetraploid hybrids derived from East African highland bananas. Fine mapping and candidate gene identification will allow characterization of molecular mechanisms underlying the TR4 resistance. The markers developed in this study can now aid the marker-assisted selection of TR4 resistance in breeding programs around the world.

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