Single-cell multi-omics in the medicinal plant Catharanthus roseus.

Advances in omics technologies now permit the generation of highly contiguous genome assemblies, detection of transcripts and metabolites at the level of single cells and high-resolution determination of gene regulatory features. Here, using a complementary, multi-omics approach, we interrogated the monoterpene indole alkaloid (MIA) biosynthetic pathway in Catharanthus roseus, a source of leading anticancer drugs. We identified clusters of genes involved in MIA biosynthesis on the eight C. roseus chromosomes and extensive gene duplication of MIA pathway genes. Clustering was not limited to the linear genome, and through chromatin interaction data, MIA pathway genes were present within the same topologically associated domain, permitting the identification of a secologanin transporter. Single-cell RNA-sequencing revealed sequential cell-type-specific partitioning of the leaf MIA biosynthetic pathway that, when coupled with a single-cell metabolomics approach, permitted the identification of a reductase that yields the bis-indole alkaloid anhydrovinblastine. We also revealed cell-type-specific expression in the root MIA pathway.

Epigenetic differences between wild and cultivated grapevines highlight the contribution of DNA methylation during crop domestication.

The domestication process in grapevines has facilitated the fixation of desired traits. Nowadays, vegetative propagation through cuttings enables easier preservation of these genotypes compared to sexual reproduction. Nonetheless, even with vegetative propagation, various phenotypes are often present within the same vineyard due to the accumulation of somatic mutations. These mutations are not the sole factors influencing phenotype. Alongside somatic variations, epigenetic variation has been proposed as a pivotal player in regulating phenotypic variability acquired during domestication. The emergence of these epialleles might have significantly influenced grapevine domestication over time. This study aims to investigate the impact of domestication on methylation patterns in cultivated grapevines. Reduced-representation bisulfite sequencing was conducted on 18 cultivated and wild accessions. Results revealed that cultivated grapevines exhibited higher methylation levels than their wild counterparts. Differential Methylation Analysis between wild and cultivated grapevines identified a total of 9955 differentially methylated cytosines, of which 78% were hypermethylated in cultivated grapevines. Functional analysis shows that core methylated genes (consistently methylated in both wild and cultivated accessions) are associated with stress response and terpenoid/isoprenoid metabolic processes. Meanwhile, genes with differential methylation are linked to protein targeting to the peroxisome, ethylene regulation, histone modifications, and defense response. Collectively, our results highlight the significant roles that epialleles may have played throughout the domestication history of grapevines.

Parental bias in expression and interaction of genes in the equine placenta.

Most autosomal genes in the placenta show a biallelic expression pattern. However, some genes exhibit allele-specific transcription depending on the parental origin of the chromosomes on which the copy of the gene resides. Parentally expressed genes are involved in the reciprocal interaction between maternal and paternal genes, coordinating the allocation of resources between fetus and mother. One of the main challenges of studying parental-specific allelic expression (allele-specific expression [ASE]) in the placenta is the maternal cellular remnant at the fetomaternal interface. Horses (Equus caballus) have an epitheliochorial placenta in which both the endometrial epithelium and the epithelium of the chorionic villi are juxtaposed with minimal extension into the uterine mucosa, yet there is no information available on the allelic gene expression of equine chorioallantois (CA). In the current study, we present a dataset of 1,336 genes showing ASE in the equine CA (https://pouya-dini.github.io/equine-gene-db/) along with a workflow for analyzing ASE genes. We further identified 254 potentially imprinted genes among the parentally expressed genes in the equine CA and evaluated the expression pattern of these genes throughout gestation. Our gene ontology analysis implies that maternally expressed genes tend to decrease the length of gestation, while paternally expressed genes extend the length of gestation. This study provides fundamental information regarding parental gene expression during equine pregnancy, a species with a negligible amount of maternal cellular remnant in its placenta. This information will provide the basis for a better understanding of the role of parental gene expression in the placenta during gestation.

Muscle glycogen unavailability and fat oxidation rate during exercise: Insights from McArdle disease.

Carbohydrate availability affects fat metabolism during exercise; however, the effects of complete muscle glycogen unavailability on maximal fat oxidation (MFO) rate remain unknown. Our purpose was to examine the MFO rate in patients with McArdle disease, comprising an inherited condition caused by complete blockade of muscle glycogen metabolism, compared to healthy controls. Nine patients (three women, aged 36 ± 12 years) and 12 healthy controls (four women, aged 40 ± 13 years) were studied. Several molecular markers of lipid transport/metabolism were also determined in skeletal muscle (gastrocnemius) and white adipose tissue of McArdle (Pygm p.50R*/p.50R*) and wild-type male mice. Peak oxygen uptake ( V ̇ O 2 peak ${\dot V_{{{\rm{O}}_{\rm{2}}}{\rm{peak}}}}$ ), MFO rate, the exercise intensity eliciting MFO rate (FATmax) and the MFO rate-associated workload were determined by indirect calorimetry during an incremental cycle-ergometer test. Despite having a much lower V ̇ O 2 peak ${\dot V_{{{\rm{O}}_{\rm{2}}}{\rm{peak}}}}$ (24.7 ± 4 vs. 42.5 ± 11.4 mL kg-1  min-1 , respectively; P < 0.0001), patients showed considerably higher values for the MFO rate (0.53 ± 0.12 vs. 0.33 ± 0.10 g min-1 , P = 0.001), and for the FATmax (94.4 ± 7.2 vs. 41.3 ± 9.1 % of V ̇ O 2 peak ${\dot V_{{{\rm{O}}_{\rm{2}}}{\rm{peak}}}}$ , P < 0.0001) and MFO rate-associated workload (1.33 ± 0.35 vs. 0.81 ± 0.54 W kg-1 , P = 0.020) than controls. No between-group differences were found overall in molecular markers of lipid transport/metabolism in mice. In summary, patients with McArdle disease show an exceptionally high MFO rate, which they attained at near-maximal exercise capacity. Pending more mechanistic explanations, these findings support the influence of glycogen availability on MFO rate and suggest that these patients develop a unique fat oxidation capacity, possibly as an adaptation to compensate for the inherited blockade in glycogen metabolism, and point to MFO rate as a potential limiting factor of exercise tolerance in this disease. KEY POINTS: Physically active McArdle patients show an exceptional fat oxidation capacity. Maximal fat oxidation rate occurs near-maximal exercise capacity in these patients. McArdle patients' exercise tolerance might rely on maximal fat oxidation rate capacity. Hyperpnoea might cloud substrate oxidation measurements in some patients. An animal model revealed overall no higher molecular markers of lipid transport/metabolism.

Phylogeny-Aware Chemoinformatic Analysis of Chemical Diversity in Lamiaceae Enables Iridoid Pathway Assembly and Discovery of Aucubin Synthase.

Countless reports describe the isolation and structural characterization of natural products, yet this information remains disconnected and underutilized. Using a cheminformatics approach, we leverage the reported observations of iridoid glucosides with the known phylogeny of a large iridoid producing plant family (Lamiaceae) to generate a set of biosynthetic pathways that best explain the extant iridoid chemical diversity. We developed a pathway reconstruction algorithm that connects iridoid reports via reactions and prunes this solution space by considering phylogenetic relationships between genera. We formulate a model that emulates the evolution of iridoid glucosides to create a synthetic data set, used to select the parameters that would best reconstruct the pathways, and apply them to the iridoid data set to generate pathway hypotheses. These computationally generated pathways were then used as the basis by which to select and screen biosynthetic enzyme candidates. Our model was successfully applied to discover a cytochrome P450 enzyme from Callicarpa americana that catalyzes the oxidation of bartsioside to aucubin, predicted by our model despite neither molecule having been observed in the genus. We also demonstrate aucubin synthase activity in orthologues of Vitex agnus-castus, and the outgroup Paulownia tomentosa, further strengthening the hypothesis, enabled by our model, that the reaction was present in the ancestral biosynthetic pathway. This is the first systematic hypothesis on the epi-iridoid glucosides biosynthesis in 25 years and sets the stage for streamlined work on the iridoid pathway. This work highlights how curation and computational analysis of widely available structural data can facilitate hypothesis-based gene discovery.

Residual effects of 12 weeks of power-oriented resistance training plus high-intensity interval training on muscle dysfunction, systemic oxidative damage, and antioxidant capacity after 10 months of training cessation in older people with COPD.

OBJECTIVE: This study aimed to assess the residual effects of a 12-week concurrent training program (power training + high-intensity interval training) in older adults with chronic obstructive pulmonary disease (COPD). METHODS: A total of 21 older adults with COPD [intervention (INT), n = 8; control (CON), n = 13; 76.9 ± 6.8 years] were assessed at baseline and 10 months after the completion of the intervention by the short physical performance battery (SPPB), health-related quality of life (EQ-5D-5L), vastus lateralis muscle thickness (MT), peak pulmonary oxygen uptake (peak VO2 ) and peak work rate (Wpeak ), early and late isometric rate of force development (RFD), leg and chest press maximum muscle power (LPmax and CPmax ), and systemic oxidative damage and antioxidant capacity. RESULTS: Compared to baseline, after 10 months of detraining, the INT group presented increased SPPB (∆ = 1.0 point), health-related quality of life (∆ = 0.07 points), early RFD (∆ = 834 N∙s-1 ), LPmax (∆ = 62.2 W), and CPmax (∆ = 16.0 W) (all p < 0.05). In addition, a positive effect was noted in INT compared to CON regarding MT and Wpeak (both p < 0.05). No between-group differences were reported in peak VO2 , late RFD, systemic oxidative damage, and antioxidant capacity from baseline to 10 months after the completion of the intervention (all p > 0.05). CONCLUSIONS: Twelve weeks of concurrent training were enough to ensure improved physical function, health-related quality of life, early RFD and maximum muscle power and to preserve MT and Wpeak but not peak VO2 , late RFD, systemic oxidative damage and antioxidant capacity in the subsequent 10 months of detraining in older adults with COPD.

Exercise effects on functional capacity and quality of life in older patients with colorectal cancer: study protocol for the ECOOL randomized controlled trial.

BACKGROUND: Surgery and treatment for colorectal cancer (CRC) in the elderly patient increase the risk of developing post-operative complications, losing functional independence, and worsening health-related quality of life (HRQoL). There is a lack of high-quality randomized controlled trials evaluating the potential benefit of exercise as a countermeasure. The primary aim of this study is to evaluate the effectiveness of a home-based multicomponent exercise program for improving HRQoL and functional capacity in older adults undergoing CRC surgery and treatment. METHODS: This randomized, controlled, observer-blinded, single-center trial aims to randomize 250 patients (>74 years) to either an intervention or a control group (i.e., usual care). The intervention group will perform an individualized home-based multicomponent exercise program with weekly telephone supervision from diagnosis until three months post-surgery. The primary outcomes will be HRQoL (EORTC QLQ-C30; CR29; and ELD14) and functional capacity (Barthel Index and Short Physical Performance Battery), which will be assessed at diagnosis, at discharge, and one, three, and six months after surgery. Secondary outcomes will be frailty, physical fitness, physical activity, inspiratory muscle function, sarcopenia and cachexia, anxiety and depression, ambulation ability, surgical complications, and hospital length of stay, readmission and mortality. DISCUSSION: This study will examine the effects of an exercise program in older patients with CRC across a range of health-related outcomes. Expected findings are improvement in HRQoL and physical functioning. If proven effective, this simple exercise program may be applied in clinical practice to improve CRC care in older patients. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT05448846.

ChromoMap: an R package for interactive visualization of multi-omics data and annotation of chromosomes.

BACKGROUND: The recent advancements in high-throughput sequencing have resulted in the availability of annotated genomes, as well as of multi-omics data for many living organisms. This has increased the need for graphic tools that allow the concurrent visualization of genomes and feature-associated multi-omics data on single publication-ready plots. RESULTS: We present chromoMap, an R package, developed for the construction of interactive visualizations of chromosomes/chromosomal regions, mapping of any chromosomal feature with known coordinates (i.e., protein coding genes, transposable elements, non-coding RNAs, microsatellites, etc.), and chromosomal regional characteristics (i.e. genomic feature density, gene expression, DNA methylation, chromatin modifications, etc.) of organisms with a genome assembly. ChromoMap can also integrate multi-omics data (genomics, transcriptomics and epigenomics) in relation to their occurrence across chromosomes. ChromoMap takes tab-delimited files (BED like) or alternatively R objects to specify the genomic co-ordinates of the chromosomes and elements to annotate. Rendered chromosomes are composed of continuous windows of a given range, which, on hover, display detailed information about the elements annotated within that range. By adjusting parameters of a single function, users can generate a variety of plots that can either be saved as static image or as HTML documents. CONCLUSIONS: ChromoMap's flexibility allows for concurrent visualization of genomic data in each strand of a given chromosome, or of more than one homologous chromosome; allowing the comparison of multi-omic data between genotypes (e.g. species, varieties, etc.) or between homologous chromosomes of phased diploid/polyploid genomes. chromoMap is an extensive tool that can be potentially used in various bioinformatics analysis pipelines for genomic visualization of multi-omics data.

Phylogenomics reveals extensive introgression and a case of mito-nuclear discordance in the killifish genus Kryptolebias.

Introgression is a widespread evolutionary process leading to phylogenetic inconsistencies among distinct parts of the genomes, particularly between mitochondrial and nuclear-based phylogenetic reconstructions (e.g., mito-nuclear discordances). Here, we used mtDNA and genome-wide nuclear sites to provide the first phylogenomic-based hypothesis on the evolutionary relationships within the killifish genus Kryptolebias. In addition, we tested for evidence of past introgression in the genus given the multiple reports of undergoing hybridization between its members. Our mtDNA phylogeny generally agreed with the relationships previously proposed for the genus. However, our reconstruction based on nuclear DNA revealed an unknown lineage - Kryptolebias sp. 'ESP' - as the sister group of the self-fertilizing mangrove killifishes, K. marmoratus and K. hermaphroditus. All individuals sequenced of Kryptolebias sp. 'ESP' had the same mtDNA haplotype commonly observed in K. hermaphroditus, demonstrating a clear case of mito-nuclear discordance. Our analysis further confirmed extensive history of introgression between Kryptolebias sp. 'ESP' and K. hermaphroditus. Population genomics analyses indicate no current gene flow between the two lineages, despite their current sympatry and history of introgression. We also confirmed introgression between other species pairs in the genus that have been recently reported to form hybrid zones. Overall, our study provides a phylogenomic reconstruction covering most of the Kryptolebias species, reveals a new lineage hidden in a case of mito-nuclear discordance, and provides evidence of multiple events of ancestral introgression in the genus. These findings underscore the importance of investigating different genomic information in a phylogenetic framework, particularly in taxa where introgression is common as in the sexually diverse mangrove killifishes.

Neuromuscular adaptations after 12 weeks of light- vs. heavy-load power-oriented resistance training in older adults.

This study aimed to determine the specific adaptations provoked by power-oriented resistance training using light (LL-PT, 40% 1-RM) vs. heavy (HL-PT, 80% 1-RM) loads in older adults. Using a randomized within-subject study design, 45 older adults (>65 years) completed an 8-week control period (CTR) followed by 12 weeks of unilateral LL-PT vs. HL-PT on a leg press. The 1-RM, theoretical force at zero velocity (F0 ), maximal unloaded velocity (V0 ), and maximal muscle power (Pmax ) were determined through a force-velocity relationship test. Isometrically, the rate of force development (RFD) and the corresponding muscle excitation of the knee extensor muscles were assessed. In addition, muscle cross-sectional area (CSA) and architecture of two quadriceps muscles were determined. Changes after CTR, LL-PT and HL-PT were compared using linear mixed models. HL-PT provoked greater improvements in 1-RM and F0 (effect size (ES) = 0.55-0.68; p < 0.001) than those observed after LL-PT (ES = 0.27-0.47; p ≤ 0.001) (post hoc treatment effect, p ≤ 0.057). By contrast, ES of changes in V0 was greater in LL-PT compared to HL-PT (ES = 0.71, p < 0.001 vs. ES = 0.39, p < 0.001), but this difference was not statistically significant. Both power training interventions elicited a moderate increase in Pmax (ES = 0.65-0.69, p < 0.001). Only LL-PT improved early RFD (ie, ≤100 ms) and muscle excitation (ES = 0.36-0.60, p < 0.05). Increased CSA were noted after both power training programs (ES = 0.13-0.35, p < 0.035), whereas pennation angle increased only after HL-PT (ES = 0.37, p = 0.004). In conclusion, HL-PT seems to be more effective in improving the capability to generate large forces, whereas LL-PT appears to trigger greater gains in movement velocity in older adults. However, both interventions promoted similar increases in muscle power as well as muscle hypertrophy.

A novel equation that incorporates the linear and hyperbolic nature of the force-velocity relationship in lower and upper limb exercises.

The purpose of this study is to provide a force-velocity (F-V) equation that combines a linear and a hyperbolic region, and to compare its derived results to those obtained from linear equations. A total of 10 cross-training athletes and 14 recreationally resistance-trained young men were assessed in the unilateral leg press (LP) and bilateral bench press (BP) exercises, respectively. F-V data were recorded using a force plate and a linear encoder. Estimated maximum isometric force (F0), maximum muscle power (Pmax), and maximum unloaded velocity (V0) were calculated using a hybrid (linear and hyperbolic) equation and three different linear equations: one derived from the hybrid equation (linearhyb), one applied to data from 0 to 100% of F0 (linear0-100), and one applied to data from 45 to 100% of F0 (linear45-100). The hybrid equation presented the best fit to the recorded data (R2 = 0.996 and 0.998). Compared to the results derived from the hybrid equation in the LP, significant differences were observed in F0 derived from linear0-100; V0 derived from linearhyb, linear0-100 and linear45-100; and Pmax derived from linearhyb and linear45-100 (all p < 0.05). For the BP, compared to the hybrid equation, significant differences were found in F0 derived from linear0-100; and V0 and Pmax derived from linearhyb, linear0-100 and linear45-100 (all p < 0.05). An F-V equation combining a linear and a hyperbolic region showed to fit adequately recorded F-V data from ~ 20 to 100% of F0, and overcame the limitations shown by linear equations while providing relevant results.

Increased Fat Oxidation During Arm Cycling Exercise in Adult Men With Spinal Cord Injury Compared With Noninjured Controls.

People with spinal cord injury (SCI) tend to be more sedentary and increase fat accumulation, which could have a negative influence on metabolic flexibility. The aim of this study was to investigate the capacity to oxidize fat in a homogenous sample of men with thoracic SCI compared with healthy noninjured men during an arm cycling incremental test. Forty-one men, 21 with SCI and 20 noninjured controls, performed an incremental arm cycling test to determine peak fat oxidation (PFO) and the intensity of exercise that elicits PFO (Fatmax). PFO was expressed in absolute values (g/min) and relative to whole-body and upper-body lean mass ([mg·min-1]·kg-1) through three different models (adjusting by cardiorespiratory fitness and fat mass). Gross mechanical efficiency was also calculated. PFO was higher in SCI than in noninjured men (0.27 ± 0.07 vs. 0.17 ± 0.07 g/min; 5.39 ± 1.30 vs. 3.29 ± 1.31 [mg·min-1]·kg-1 whole-body lean mass; 8.28 ± 2.11 vs. 5.08 ± 2.12 [mg·min-1]·kg-1 upper-body lean mass). Fatmax was found at a significantly higher percentage of VO2peak in men with SCI (33.6% ± 8.2% vs. 23.6% ± 6.4%). Differences persisted and even increased in the fully adjustment model and at any intensity. Men with SCI showed significantly higher gross mechanical efficiency at 35 and 65 W than the noninjured group. Men with SCI showed higher fat oxidation when compared with noninjured men at any intensity, even increased after full adjustment for lean mass, fat mass, and cardiorespiratory fitness. These findings suggest that SCI men could improve their metabolic flexibility and muscle mass for greater efficiency, not being affected by their fat accumulation.

Botrytis cinerea Loss and Restoration of Virulence during In Vitro Culture Follows Flux in Global DNA Methylation.

Pathogenic fungi can lose virulence after protracted periods of culture, but little is known of the underlying mechanisms. Here, we present the first analysis of DNA methylation flux at a single-base resolution for the plant pathogen B. cinerea and identify differentially methylated genes/genomic regions associated with virulence erosion during in vitro culture. Cultures were maintained for eight months, with subcultures and virulence testing every month. Methylation-sensitive amplified polymorphisms were performed at monthly intervals to characterise global changes to the pathogen's genome during culture and also on DNA from mycelium inoculated onto Arabidopsis thaliana after eight months in culture. Characterisation of culture-induced epialleles was assessed by whole-genome re-sequencing and whole-genome bisulfite sequencing. Virulence declined with time in culture and recovered after inoculation on A. thaliana. Variation detected by methylation-sensitive amplified polymorphisms followed virulence changes during culture. Whole-genome (bisulfite) sequencing showed marked changes in global and local methylation during culture but no significant genetic changes. We imply that virulence is a non-essential plastic character that is at least partly modified by the changing levels of DNA methylation during culture. We hypothesise that changing DNA methylation during culture may be responsible for the high virulence/low virulence transition in B. cinerea and speculate that this may offer fresh opportunities to control pathogen virulence.

Mechanical Characteristics of Heavy vs. Light Load Ballistic Resistance Training in Older Adults.

ABSTRACT: Rodriguez-Lopez, C, Alcazar, J, Sánchez-Martín, C, Ara, I, Csapo, R, and Alegre, LM. Mechanical characteristics in heavy vs. light load ballistic resistance training in older adults. J Strength Cond Res 36(8): 2094-2101, 2022-Although power-oriented resistance training (RT) is strongly recommended to counter age-related neuromuscular function declines, there is still controversy about which intensities of load should be used to elicit optimal training adaptations. Knowledge of the mechanical characteristics of power-oriented RT performed at different intensities might help to better understand the training stimulus that triggers load-dependent adaptations in older adults. Using a cross-over design, 15 well-functioning older volunteers (9 men and 6 women; 73.6 ± 3.8 years) completed 2 volume × load-matched ballistic RT sessions with heavy (HL: 6 × 6 × 80% 1-repetition maximum [1RM]) and light-load (LL: 6 × 12 × 40% 1RM) on a horizontal leg press exercise. Electromyographic (EMG) and mechanical variables (work, force, velocity, and power) as well as intraset neuromuscular fatigue (i.e., relative losses in force, velocity, and power) were analyzed. More concentric mechanical work was performed in the LL training session, compared with HL (36.2 ± 11.2%; p < 0.001). Despite the higher mean EMG activity of the quadriceps femoris muscle (13.2 ± 21.1%; p = 0.038) and greater concentric force (35.2 ± 7.6%; p < 0.001) during HL, higher concentric velocity (41.0 ± 12.7%, p < 0.001) and a trend toward higher concentric power (7.2 ± 18.9%, p = 0.075) were found for LL. Relative velocity losses were similar in both sessions (≈10%); however, relative force losses were only found in LL (7.4 ± 6.5%, p = 0.003). Considering the greater mechanical work performed and concentric power generated, ballistic RT using LL may, therefore, represent a stronger stimulus driving training adaptations as compared with volume × load-matched heavy-load training. Relative losses in force and power should be monitored in addition to velocity losses during ballistic RT.

Two bi-functional cytochrome P450 CYP72 enzymes from olive (Olea europaea) catalyze the oxidative C-C bond cleavage in the biosynthesis of secoxy-iridoids - flavor and quality determinants in olive oil.

Olive (Olea europaea) is an important crop in Europe, with high cultural, economic and nutritional significance. Olive oil flavor and quality depend on phenolic secoiridoids, but the biosynthetic pathway of these iridoids remains largely uncharacterized. We discovered two bifunctional cytochrome P450 enzymes, catalyzing the rare oxidative C-C bond cleavage of 7-epi-loganin to produce oleoside methyl ester (OeOMES) and secoxyloganin (OeSXS), both through a ketologanin intermediary. Although these enzymes are homologous to the previously reported Catharanthus roseus secologanin synthase (CrSLS), the substrate and product profiles differ. Biochemical assays provided mechanistic insights into the two-step OeOMES and CrSLS reactions. Model-guided mutations of OeOMES changed the product profile in a predictable manner, revealing insights into the molecular basis for this change in product specificity. Our results suggest that, in contrast to published hypotheses, in planta production of secoxy-iridoids is secologanin-independent. Notably, sequence data of cultivated and wild olives point to a relation between domestication and OeOMES expression. Thus, the discovery of this key biosynthetic gene suggests a link between domestication and secondary metabolism, and could potentially be used as a genetic marker to guide next-generation breeding programs.

Reduced knee extensor torque production at low to moderate velocities in postmenopausal women with knee osteoarthritis.

This study aimed to determine deficits in knee extensor muscle function through the torque-time and torque-velocity relationships and whether these deficits are associated with reduced functional performance in postmenopausal women with knee osteoarthritis (KOA). A clinical sample of postmenopausal women with established KOA (n = 18, ≥55 years) was compared to an age-matched healthy control sample (CON) (n = 26). The deficits in different parameters of the knee extensor torque-time (maximal isometric torque and rate of torque development) and torque-velocity relationship (maximum muscle power, maximal velocity and torque at 0-500°·s-1 ) were assessed through a protocol consisting of isometric, isotonic and isokinetic tests. Functional performance was evaluated with sit-to-stand and stair-climbing tasks using a sensor-based technology (ie, time- and power-based outcomes). Postmenopausal women with KOA showed reduced maximal isometric torque (Hedge's g effect size (g) = 1.05, p = 0.001) and rate of torque development (g = 0.77-1.17, all p ≤ 0.02), combined with impaired torque production at slow to moderate velocities (g = 0.92-1.70, p ≤ 0.004), but not at high or maximal velocities (g = 0.16, p > 0.05). KOA were slower (g = 0.81-0.92, p ≤ 0.011) and less powerful (g = 1.11-1.29, p ≤ 0.001) during functional tasks. Additionally, knee extensor deficits were moderately associated with power deficits in stair climbing (r = 0.492-0.659). To conclude, knee extensor muscle weakness was presented in postmenopausal women with KOA, not only as limited maximal and rapid torque development during isometric contractions, but also dynamically at low to moderate velocities. These deficits were related to impaired functional performance. The assessment of knee extensor muscle weakness through the torque-time and torque-velocity relationships might enable individual targets for tailored exercise interventions in KOA.

Acute Physiological Response to Light- and Heavy-load Power-oriented Exercise in Older Adults.

This study investigated the acute responses to volume-load-matched heavy-load (80% 1RM) versus light-load (40% 1RM) power-oriented resistance training sessions in well-functioning older adults. Using a randomized cross-over design, 15 volunteers completed each condition on a leg press. Neuromuscular (maximal isometric force and rate of force development) and functional performance (power during sit-to-stand test), lactate, and muscle damage biochemistry (creatine kinase, lactate dehydrogenase and C-reactive protein serum concentration) were assessed pre- and post-exercise. Performance declines were found after heavy-load (Cohen's d effect size (d); maximal isometric force=0.95 d; rate of force development=1.17 d; sit-to-stand power =0.38 d, all p<0.05) and light-load (maximal isometric force=0.45 d; rate of force development=0.9 d; sit-to-stand power=1.17 d, all p<0.05), while lactate concentration increased only after light-load (1.7 d, p=0.001). However, no differences were found between conditions (all p>0.05). Both conditions increased creatine kinase the day after exercise (marginal effect=0.75 d, p<0.001), but no other blood markers increased (all, p>0.05). Irrespective of the load used, power training induced non-clinically significant decreases in sit-to-stand performance, moderate declines in maximal isometric force, but pronounced decreases in the rate of force development. Furthermore, the metabolic stress and muscle damage were minor; both sessions were generally well tolerated by well-functioning older adults without previous experience in resistance training.

Effects of velocity loss in the bench press exercise on strength gains, neuromuscular adaptations, and muscle hypertrophy.

OBJECTIVE: This study aimed to compare the effects of four velocity-based training (VBT) programs in bench press (BP) between a wide range of velocity loss (VL) thresholds-0% (VL0), 15% (VL15), 25% (VL25), and 50% (VL50)-on strength gains, neuromuscular adaptations, and muscle hypertrophy. METHODS: Sixty-four resistance-trained young men were randomly assigned into four groups (VL0, VL15, VL25, and VL50) that differed in the VL allowed in each set. Subjects followed a VBT program for 8-weeks using the BP exercise. Before and after the VBT program the following tests were performed: (a) cross-sectional area (CSA) measurements of pectoralis major (PM) muscle; (b) maximal isometric test; (c) progressive loading test; and (d) fatigue test. RESULTS: Significant group x time interactions were observed for CSA (P < .01) and peak root mean square in PM (peak RMS-PM, P < .05). VL50 showed significantly greater gains in CSA than VL0 (P < .05). Only the VL15 group showed significant increases in peak RMS-PM (P < .01). Moreover, only VL0 showed significant gains in the early rate of force development (RFD, P = .05), while VL25 and VL50 improved in the late RFD (P ≤ .01-.05). No significant group × time interactions were found for any of the dynamic strength variables analyzed, although all groups showed significant improvements in all these parameters. CONCLUSION: Higher VL thresholds allowed for a greater volume load which maximized muscle hypertrophy, whereas lower VL thresholds evoked positive neuromuscular-related adaptations. No significant differences were found between groups for strength gains, despite the wide differences in the total volume accumulated by each group.

Metabolomics Analysis Reveals Tissue-Specific Metabolite Compositions in Leaf Blade and Traps of Carnivorous Nepenthes Plants.

Nepenthes is a genus of carnivorous plants that evolved a pitfall trap, the pitcher, to catch and digest insect prey to obtain additional nutrients. Each pitcher is part of the whole leaf, together with a leaf blade. These two completely different parts of the same organ were studied separately in a non-targeted metabolomics approach in Nepenthes x ventrata, a robust natural hybrid. The first aim was the analysis and profiling of small (50-1000 m/z) polar and non-polar molecules to find a characteristic metabolite pattern for the particular tissues. Second, the impact of insect feeding on the metabolome of the pitcher and leaf blade was studied. Using UPLC-ESI-qTOF and cheminformatics, about 2000 features (MS/MS events) were detected in the two tissues. They showed a huge chemical diversity, harboring classes of chemical substances that significantly discriminate these tissues. Among the common constituents of N. x ventrata are phenolics, flavonoids and naphthoquinones, namely plumbagin, a characteristic compound for carnivorous Nepenthales, and many yet-unknown compounds. Upon insect feeding, only in pitchers in the polar compounds fraction, small but significant differences could be detected. By further integrating information with cheminformatics approaches, we provide and discuss evidence that the metabolite composition of the tissues can point to their function.

The complexity of intercellular localisation of alkaloids revealed by single-cell metabolomics.

Catharanthus roseus is a medicinal plant well known for producing bioactive compounds such as vinblastine and vincristine, which are classified as terpenoid indole alkaloids (TIAs). Although the leaves of this plant are the main source of these antitumour drugs, much remains unknown on how TIAs are biosynthesised from a central precursor, strictosidine, to various TIAs in planta. Here, we have succeeded in showing, for the first time in leaf tissue of C. roseus, cell-specific TIAs localisation and accumulation with 10 µm spatial resolution Imaging mass spectrometry (Imaging MS) and live single-cell mass spectrometry (single-cell MS). These metabolomic studies revealed that most TIA precursors (iridoids) are localised in the epidermal cells, but major TIAs including serpentine and vindoline are localised instead in idioblast cells. Interestingly, the central TIA intermediate strictosidine also accumulates in both epidermal and idioblast cells of C. roseus. Moreover, we also found that vindoline accumulation increases in laticifer cells as the leaf expands. These discoveries highlight the complexity of intercellular localisation in plant specialised metabolism.