Genetic association analysis in sugarcane (Saccharum spp.) for sucrose accumulation in humid environments in Colombia.

BACKGROUND: Sucrose accumulation in sugarcane is affected by several environmental and genetic factors, with plant moisture being of critical importance for its role in the synthesis and transport of sugars within the cane stalks, affecting the sucrose concentration. In general, rainfall and high soil humidity during the ripening stage promote plant growth, increasing the fresh weight and decreasing the sucrose yield in the humid region of Colombia. Therefore, this study aimed to identify markers associated with sucrose accumulation or production in the humid environment of Colombia through a genome-wide association study (GWAS). RESULTS: Sucrose concentration measurements were taken in 220 genotypes from the Cenicaña's diverse panel at 10 (early maturity) and 13 (normal maturity) months after planting. For early maturity data was collected during plant cane and first ratoon, while at normal maturity it was during plant cane, first, and second ratoon. A total of 137,890 SNPs were selected after sequencing the 220 genotypes through GBS, RADSeq, and whole-genome sequencing. After GWAS analysis, a total of 77 markers were significantly associated with sucrose concentration at both ages, but only 39 were close to candidate genes previously reported for sucrose accumulation and/or production. Among the candidate genes, 18 were highlighted because they were involved in sucrose hydrolysis (SUS6, CIN3, CINV1, CINV2), sugar transport (i.e., MST1, MST2, PLT5, SUT4, ERD6 like), phosphorylation processes (TPS genes), glycolysis (PFP-ALPHA, HXK3, PHI1), and transcription factors (ERF12, ERF112). Similarly, 64 genes were associated with glycosyltransferases, glycosidases, and hormones. CONCLUSIONS: These results provide new insights into the molecular mechanisms involved in sucrose accumulation in sugarcane and contribute with important genomic resources for future research in the humid environments of Colombia. Similarly, the markers identified will be validated for their potential application within Cenicaña's breeding program to assist the development of breeding populations.

A horizontally gene transferred copper resistance locus confers hyper-resistance to antibacterial copper toxicity and enables survival of community acquired methicillin resistant Staphylococcus aureus USA300 in macrophages.

Excess copper is highly toxic and forms part of the host innate immune system's antibacterial arsenal, accumulating at sites of infection and acting within macrophages to kill engulfed pathogens. We show for the first time that a novel, horizontally gene transferred copper resistance locus (copXL), uniquely associated with the SCCmec elements of the highly virulent, epidemic, community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) USA300, confers copper hyper-resistance. These genes are additional to existing core genome copper resistance mechanisms, and are not found in typical S. aureus lineages, but are increasingly identified in emerging pathogenic isolates. Our data show that CopX, a putative P1B-3 -ATPase efflux transporter, and CopL, a novel lipoprotein, confer copper hyper-resistance compared to typical S. aureus strains. The copXL genes form an operon that is tightly repressed in low copper environments by the copper regulator CsoR. Significantly, CopX and CopL are important for S. aureus USA300 intracellular survival within macrophages. Therefore, the emergence of new S. aureus clones with the copXL locus has significant implications for public health because these genes confer increased resistance to antibacterial copper toxicity, enhancing bacterial fitness by altering S. aureus interaction with innate immunity.

A cascade of sequentially expressed sucrose transporters in the seed coat and endosperm provides nutrition for the Arabidopsis embryo.

Developing plant embryos depend on nutrition from maternal tissues via the seed coat and endosperm, but the mechanisms that supply nutrients to plant embryos have remained elusive. Sucrose, the major transport form of carbohydrate in plants, is delivered via the phloem to the maternal seed coat and then secreted from the seed coat to feed the embryo. Here, we show that seed filling in Arabidopsis thaliana requires the three sucrose transporters SWEET11, 12, and 15. SWEET11, 12, and 15 exhibit specific spatiotemporal expression patterns in developing seeds, but only a sweet11;12;15 triple mutant showed severe seed defects, which include retarded embryo development, reduced seed weight, and reduced starch and lipid content, causing a "wrinkled" seed phenotype. In sweet11;12;15 triple mutants, starch accumulated in the seed coat but not the embryo, implicating SWEET-mediated sucrose efflux in the transfer of sugars from seed coat to embryo. This cascade of sequentially expressed SWEETs provides the feeding pathway for the plant embryo, an important feature for yield potential.

Long-term outcomes of different ablation strategies for ventricular tachycardia in patients with structural heart disease: systematic review and meta-analysis.

Aims: To compare the long-term outcomes of standard ablation of stable ventricular tachycardia (VT) vs. substrate modification, and of complete vs. incomplete substrate modification in patients with structural heart disease (SHD) presenting with VT. Methods and results: An electronic search was performed using major databases. The main outcomes were a composite of long-term ventricular arrhythmia (VA) recurrence and all-cause mortality of standard ablation of stable VT vs. substrate modification, and long-term VA recurrence in complete vs. incomplete substrate modification. Six studies were included for the comparison of standard ablation of stable VT vs. substrate modification, with a total of 396 patients (mean age 63 ± 10 years, 87% males), and seven studies were included to assess the impact of extensive substrate modification, with a total of 391 patients (mean age 64 ± years, 90% males). More than 70% of all the patients included had ischaemic cardiomyopathy. Substrate modification was associated with decreased composite VA recurrence/all-cause mortality compared to standard ablation of stable VTs [risk ratio (RR) 0.57, 95% confidence interval (CI) 0.40-0.81]. Complete substrate modification was associated with decreased VA recurrence as compared to incomplete substrate modification (RR 0.39, 95% CI 0.27-0.58). Conclusion: In patients with SHD who had VT related mainly to ischaemic substrates, there was a significantly lower risk of the composite primary outcome of long-term VA recurrence and all-cause mortality among those undergoing substrate modification compared to standard ablation. Long-term success is improved when performing complete substrate modification.

Clinical Impact of Heparin Kinetics During Catheter Ablation of Atrial Fibrillation: Meta-Analysis and Meta-Regression.

INTRODUCTION: Appropriate activated clotting time (ACT) during catheter ablation of atrial fibrillation (CA-AF) is essential to minimize periprocedural complications. METHODS AND RESULTS: An electronic search was performed using major databases. Outcomes were thromboembolic (TE) and bleeding complications according to ACT levels (seconds). Heparin dose (U/kg) and time (minutes) to achieve the target ACT was compared among patients receiving vitamin K antagonist (VKA) versus non-VKA oral anticoagulants (NOAC). Nineteen studies involving 7,150 patients were identified. Patients with ACT > 300 had less TE (OR, 0.51; 95% CI 0.35-0.74) and bleeding (OR, 0.70; 95% CI 0.60-0.83) compared to ACT < 300, when using any type of oral anticoagulation. The use of VKA was associated with reduced heparin requirements (mean dose: 157 U/kg vs. 209 U/kg, P < 0.03; SDM -0.86 [95% CI -1.39 to -0.33]), and with lower time to achieve the target ACT (mean time: 24 minutes vs. 49 minutes, P < 0.03; SDM -11.02 [95% CI -13.29 to -8.75]) compared to NOACs. No significant publication bias was found. CONCLUSIONS: Performing CA-AF with a target ACT > 300 decreases the risk of TE without increasing the risk of bleeding. Patients receiving VKAs required less heparin and reached the target ACT faster compared to NOACs.

Methicillin-Susceptible, Vancomycin-Resistant Staphylococcus aureus, Brazil.

We report characterization of a methicillin-susceptible, vancomycin-resistant bloodstream isolate of Staphylococcus aureus recovered from a patient in Brazil. Emergence of vancomycin resistance in methicillin-susceptible S. aureus would indicate that this resistance trait might be poised to disseminate more rapidly among S. aureus and represents a major public health threat.

Deletion of liaR Reverses Daptomycin Resistance in Enterococcus faecium Independent of the Genetic Background.

We have shown previously that changes in LiaFSR, a three-component regulatory system predicted to orchestrate the cell membrane stress response, are important mediators of daptomycin (DAP) resistance in enterococci. Indeed, deletion of the gene encoding the response regulator LiaR in a clinical strain of Enterococcus faecalis reversed DAP resistance (DAP-R) and produced a strain hypersusceptible to antimicrobial peptides. Since LiaFSR is conserved in Enterococcus faecium, we investigated the role of LiaR in a variety of clinical E. faecium strains representing the most common DAP-R genetic backgrounds. Deletion of liaR in DAP-R E. faecium R446F (DAP MIC of 16 µg/ml) and R497F (MIC of 24 µg/ml; harboring changes in LiaRS) strains fully reversed resistance (DAP MICs decreasing to 0.25 and 0.094 µg/ml, respectively). Moreover, DAP at concentrations of 13 µg/ml (achieved with human doses of 12 mg/kg body weight) retained bactericidal activity against the mutants. Furthermore, the liaR deletion derivatives of these two DAP-R strains exhibited increased binding of boron-dipyrromethene difluoride (BODIPY)-daptomycin, suggesting that high-level DAP-R mediated by LiaR in E. faecium involves repulsion of the calcium-DAP complex from the cell surface. In DAP-tolerant strains HOU503F and HOU515F (DAP MICs within the susceptible range but bacteria not killed by DAP concentrations of 5× the MIC), deletion of liaR not only markedly decreased the DAP MICs (0.064 and 0.047 µg/ml, respectively) but also restored the bactericidal activity of DAP at concentrations as low as 4 µg/ml (achieved with human doses of 4 mg/kg). Our results suggest that LiaR plays a relevant role in the enterococcal cell membrane adaptive response to antimicrobial peptides independent of the genetic background and emerges as an attractive target to restore the activity of DAP against multidrug-resistant strains.

Sequencing vs. amplification for the estimation of allele dosages in sugarcane (Saccharum spp.).

Premise: Detecting single-nucleotide polymorphisms (SNPs) in a cost-effective way is fundamental in any plant breeding pipeline. Here, we compare three genotyping techniques for their ability to reproduce the allele dosage of SNPs of interest in sugarcane (Saccharum spp.). Methods: To identify a reproducible technique to estimate allele dosage for the validation of SNP markers, the correlation between Flex-Seq, kompetitive allele-specific PCR (KASP), and genotyping-by-sequencing and restriction site-associated DNA sequencing (GBS+RADseq) was determined for a set of 76 SNPs. To find alternative methodologies for allele dosage estimation, the KASP and Flex-Seq techniques were compared for the same set of SNPs. For the three techniques, a population of 53 genotypes from the diverse sugarcane panel of the Centro de Investigación de la Caña de Azúcar (Cenicaña), Colombia, was selected. Results: The average Pearson correlation coefficients between GBS+RADseq and Flex-Seq, GBS+RADseq and KASP, and Flex-Seq and KASP were 0.62 ± 0.27, 0.38 ± 0.27, and 0.38 ± 0.30, respectively. Discussion: Flex-Seq reproduced the allele dosages determined using GBS+RADseq with good levels of precision because of its depth of sequencing and ability to target specific positions in the genome. Additionally, Flex-Seq outperformed KASP by allowing the conversion of a higher number of SNPs and a more accurate estimation of the allele dosage. Flex-Seq has therefore become the genotyping methodology of choice for marker validation at Cenicaña.

Premisa: Detectar polimorfismos de un único nucleótido (SNP) de forma costo­efectiva es fundamental en cualquier programa de mejoramiento genético. En este artículo nosotros comparamos tres técnicas de genotipado para medir su habilidad en reproducir las dosis alélicas de SNPs de interés en caña de azúcar (Saccharum spp.). Métodos: Para identificar una técnica reproducible para la estimación de dosis alélicas durante los pasos de validación de marcadores, la correlación entre Flex­Seq, kompetitive allele­specific PCR (KASP), y genotyping­by­sequencing and restriction site­associated DNA sequencing (GBS+RADseq) fue determinada para un set de 76 SNPs. Para identificar metodologías alternativas en la estimación de las dosis alélicas, las tecnologías KASP y Flex­Seq fueron comparadas para el mismo grupo de SNPs. Para las tres técnicas, una población de 53 genotipos fue seleccionados de la población diversa de caña de azúcar del Centro de Investigación de la Caña de Azúcar (Cenicaña), Colombia. Resultados: El promedio del coeficiente de correlación de Pearson entre GBS+RADseq y Flex­Seq, GBS+RADseq y KASP, y Flex­Seq y KASP fue de 0.62 ± 0.27, 0.38 ± 0.27, y 0.38 ± 0.30, respectivamente. Discusión: Flex­Seq reprodujo las dosis alélicas determinadas usando GBS+RADseq con buenos niveles de precisión debido a su profundidad de secuenciación y habilidad de secuenciar posiciones especificas en el genoma. Adicionalmente, Flex­Seq superó a KASP al permitir la conversión de un número mayor de SNPs y al estimar las dosis alélicas de forma más precisa. Flex­Seq por tanto se convierte en la metodología de genotipado de elección para la validación de marcadores en Cenicaña.

Premolar Extraction Affects Mandibular Kinematics.

OBJECTIVES: The practice of premolar extraction in orthodontics is controversial for its potential detrimental effects on the stomatognathic system. However, the ways in which premolar extraction affects mandibular function are still poorly understood. The purpose of this study was to assess the influence of premolar extraction on mandibular kinematics by evaluating axiographic tracings. MATERIALS AND METHODS: Forty-five orthodontically treated patients with premolar teeth extraction were compared with 45 paired untreated controls, selected for the absence of malocclusions. Systematic three-dimensional axiographic recordings of the mandibular movements were performed for protrusive-retrusive movements and speech. The transversal deviations and length of the movements were recorded for both sides along with the rotation angle during speech. STATISTICAL ANALYSIS: Differences between the axiographic variables were analyzed via the permutation test and Wilcoxon rank-sum test. Linear regression was performed to test whether axiographic parameters were predictive of group affiliation. Dot plots were used to explore the distribution of each of the axiographic outcomes, and isometric principal component analysis to assess the differences between the cumulative effects of premolar extraction on jaw motion. RESULTS: The mandibular lateral translation in protrusion-retrusion and speech, the amount of rotation as well as the length of mandibular movements during speech were significantly higher in the treated subjects than in the controls, while retral stability did not differ. The linear regression yielded significant results for the mandibular lateral translation in protrusion-retrusion. The isometric principal component analysis showed higher values of the axiographic variables for 11 out of 45 individuals in the study sample compared with the control group. CONCLUSIONS: Premolar extraction altered mandibular kinematics in at least 25% of the cases within our sample, and the transversal discrepancy between protrusive and retrusive tracings was even predictive of group affiliation. These results support the notion that the routine practice of premolar extraction as part of the orthodontic treatment should be discouraged. It is compelling to perform further studies to assess whether a disrupted kinematics of the mandible is associated to temporomandibular disorders.

Copper Resistance Promotes Fitness of Methicillin-Resistant Staphylococcus aureus during Urinary Tract Infection.

Urinary tract infection (UTI) is one of the most common infectious conditions affecting people in the United States and around the world. Our knowledge of the host-pathogen interaction during UTI caused by Gram-positive bacterial uropathogens is limited compared to that for Gram-negative pathogens. Here, we investigated whether copper and the primary copper-containing protein, ceruloplasmin, are mobilized to urine during naturally occurring UTI caused by Gram-positive uropathogens in patients. Next, we probed the role of copper resistance in the fitness of methicillin-resistant Staphylococcus aureus (MRSA) during experimental UTI in a murine model. Our findings demonstrate that urinary copper and ceruloplasmin content are elevated during UTI caused by Enterococcus faecalis, S. aureus, S. epidermidis, and S. saprophyticus. MRSA strains successfully colonize the urinary tract of female CBA mice with selective induction of inflammation in the kidneys but not the bladder. MRSA mutants lacking CopL, a copper-binding cell surface lipoprotein, and the ACME genomic region containing copL, exhibit decreased fitness in the mouse urinary tract compared to parental strains. Copper sensitivity assays, cell-associated copper and iron content, and bioavailability of iron during copper stress demonstrate that homeostasis of copper and iron is interlinked in S. aureus. Importantly, relative fitness of the MRSA mutant lacking the ACME region is further decreased in mice that receive supplemental copper compared to the parental strain. In summary, copper is mobilized to the urinary tract during UTI caused by Gram-positive pathogens, and copper resistance is a fitness factor for MRSA during UTI. IMPORTANCE Urinary tract infection (UTI) is an extremely common infectious condition affecting people throughout the world. Increasing antibiotic resistance in pathogens causing UTI threatens our ability to continue to treat patients in the clinics. Better understanding of the host-pathogen interface is critical for development of novel interventional strategies. Here, we sought to elucidate the role of copper in host-Staphylococcus aureus interaction during UTI. Our results reveal that copper is mobilized to the urine as a host response in patients with UTI. Our findings from the murine model of UTI demonstrate that copper resistance is involved in the fitness of methicillin-resistant S. aureus (MRSA) during interaction with the host. We also establish a critical link between adaptation to copper stress and iron homeostasis in S. aureus.

Association of resuscitative endovascular balloon occlusion of the aorta (REBOA) and mortality in penetrating trauma patients.

PURPOSE: The purpose of this study was to examine the association of REBOA and mortality in a group of patients with penetrating trauma to the torso, treated in a level-I trauma center from Colombia. METHODS: In a retrospective cohort study, patients with penetrating trauma, requiring emergency surgery, and treated between 2014 and 2018, were included. The decision to use or not use REBOA during emergent surgery was based on individual surgeon's opinion. A propensity score (PS) was calculated after adjusting for age, clinical signs on admission (systolic blood pressure, cardiac rate, Glasgow coma scale), severe trauma in thorax and abdomen, and the presence of non-compressive torso hemorrhage. Subsequently, logistic regression for mortality was adjusted for the number of red blood cells (RBC) transfused within the first six hours after admission, injury severity score (ISS), and quintiles of PS. RESULTS: We included 345 patients; 28 of them (8.1%) were treated with REBOA. Crude mortality rates were 17.9% (5 patients) in REBOA group and 15.3% (48 patients) in control group (p = 0.7). After controlling for RBC transfused, ISS, and the PS, the odds of death in REBOA group was 78% lower than that in the control group (odds ratio [OR] 0.20, 95% confidence interval [95%CI] 0.05-0.77, p = 0.01). CONCLUSION: We found that, when compared to no REBOA use, patients treated with REBOA had lower risk-adjusted odds of mortality. These findings should be interpreted with caution and confirmed in future comparative studies, if possible.

Three-dimensional morphological characterization of malocclusions with mandibular lateral displacement using cone-beam computed tomography.

OBJECTIVE: The purpose of this study was to evaluate the morphologic characteristics of MLD malocclusions using 3D imaging. MATERIALS AND METHODS: MLD characteristics were examined using CBCT data in 40 subjects. A 3D Cephalometric analysis was developed to describe the spatial position of the mandible and temporal bones. RESULTS: Vertical dental heights were shorter and the posterior occlusal plane (POP) presented a steeper sagittal inclination on the shifted side (the side of the laterally displaced bony chin) than on the contralateral side. (p < 0.01). The MLD was related to a superiorly inclined POP Cant in the same direction (r = 0.82; p < 0.01). The shifted side condyle was dislocated medially and was smaller. Temporal bone sagittal inclination showed a more forward and medial inclination on the contralateral side (p < 0.01). CONCLUSIONS: A unilateral decrease in the vertical height of the dentition and the subsequent steeper occlusal plane inclinations correlated with (1) mandibular rotational displacement and condylar lateral displacement, (2) mandibular and condylar morphologic changes (3) changes in temporal bone position.

Thromboembolic and bleeding risks in patients undergoing atrial fibrillation ablation: oral anticoagulation perspectives.

INTRODUCTION: Atrial fibrillation (AF) is a cause of significant morbidity and mortality. Catheter ablation for AF (CAAF) has emerged as an effective treatment option of rhythm control for patients with symptomatic AF. However, the risk of thromboembolism and bleeding in the periprocedural period represent a worrisome complication of this therapy. The reported incidence of thromboembolic and bleeding events associated with CAAF varies from 0.9% to 5% depending on the CAAF strategy and the anticoagulation regimen used in the periprocedural period. Areas covered: The different anticoagulation regimens used prior to, during, and after CAAF to minimize the risk of thromboembolic and bleeding events are reviewed. The use of uninterrupted oral anticoagulation and appropriate heparin dosing to achieve safe activated clotting time levels are also detailed. A comprehensive approach with assessment of individual risk for thromboembolic and bleeding complications, and understanding the pharmacokinetics of the anticoagulant agents available is also reviewed. Expert opinion: The key advances done in the periprocedural anticoagulation field include the use of uninterrupted anticoagulation strategies in patients undergoing AF ablation and efforts to simplify the selection of patients who need LAA thrombus screening prior to ablation.