Publications by authors named "Nathan A Johnson"

The isolated river drainages of eastern North America serve as a natural laboratory to investigate the roles of allopatry and secondary contact in the evolutionary trajectories of recently diverged lineages. Drainage divides facilitate allopatric speciation, but due to their sensitivity to climatic and geomorphological changes, neighboring rivers frequently coalesce, creating recurrent opportunities of isolation and contact throughout the history of aquatic lineages. The freshwater mussel Quadrula quadrula is widely distributed across isolated rivers of eastern North America and possesses high phenotypic and molecular variation across its range.

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Objectives: This study aimed to evaluate the effects of a novel, low-volume combined high-intensity interval training (HIIT) and progressive resistance training (PRT) in overweight/obese adults.

Methods: This randomised control trial compared the effect of regular supervised HIIT combined with PRT (Exercise) with an unsupervised stretching intervention (Control), in previously inactive adults with either normal glucose (NG), pre-diabetes or type 2 diabetes (T2DM) with body mass index of >25 kg/m. Participants were randomly allocated (1:1) to receive low-volume exercise or control by an online randomisation tool.

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Aims: To investigate circulating angiogenic cells in adults with prediabetes and the effect of a structured exercise program.

Methods: A cohort of adults with overweight/obesity and either normal glucose (NG) or prediabetes were randomised to receive exercise (Exercise) (as twice weekly supervised combined high intensity aerobic exercise and progressive resistance training, and once weekly home-based aerobic exercise) or an unsupervised stretching intervention (Control) for 12 weeks. Circulating angiogenic T cells, muscle strength, and cardiovascular disease risk factors, including blood lipids, arterial stiffness, central haemodynamic responses, and cardiorespiratory fitness (VOpeak) in those with prediabetes (n = 35, 16 Control, 19 Exercise) and NG (n = 37, 17 Control, 20 Exercise) were analysed at baseline and after the 12-week intervention.

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Article Synopsis
  • - The study aimed to determine if high-intensity interval training (HIIT) is more effective than moderate-intensity continuous training (MICT) or no exercise for improving components of metabolic syndrome (MetS) in affected individuals.
  • - A systematic review analyzed 23 randomized controlled trials (RCTs) with 1374 participants, finding that HIIT significantly improved various health metrics like waist circumference, blood pressure, cholesterol levels, triglycerides, and blood glucose compared to non-exercise control.
  • - The results suggest that HIIT is a beneficial exercise option for enhancing cardiometabolic health, with low-volume HIIT being as effective as higher-volume workouts, making it a practical alternative to traditional aerobic exercise.
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Objective: We aimed to examine the effects of a 5:2 diet (2 days per week of energy restriction by formula diet) or an exercise (2 days per week of high-intensity interval training and resistance training) intervention compared with routine lifestyle education (control) on glycemic control and cardiometabolic health among adults with overweight/obesity and type 2 diabetes.

Research Design And Methods: This two-center, open-label, three-arm, parallel-group, randomized controlled trial recruited 326 participants with overweight/obesity and type 2 diabetes and randomized them into 12 weeks of diet intervention (n = 109), exercise intervention (n = 108), or lifestyle education (control) (n = 109). The primary outcome was the change of glycemic control measured as glycated hemoglobin (HbA1c) between the diet or exercise intervention groups and the control group after the 12-week intervention.

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Characterizing the mechanisms influencing the distribution of genetic variation in aquatic species can be difficult due to the dynamic nature of hydrological landscapes. In North America's Central Highlands, a complex history of glacial dynamics, long-term isolation, and secondary contact have shaped genetic variation in aquatic species. Although the effects of glacial history have been demonstrated in many taxa, responses are often lineage- or species-specific and driven by organismal ecology.

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Nonalcoholic fatty liver disease (NAFLD) affects approximately 30% of adults worldwide, with chronic low-grade inflammation being a key pathophysiological feature of progression. The Mediterranean diet (MedDiet) is recognized for improving metabolic and hepatic outcomes in people with diabetes and NAFLD, in part, via anti-inflammatory properties. The aim of this study was to determine the effect of an ad libitum MedDiet versus low-fat diet (LFD) on inflammatory markers in adults with NAFLD.

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Metabolic-associated fatty liver disease (MAFLD) is the most prevalent chronic liver disease worldwide, affecting 25% of people globally and up to 80% of people with obesity. MAFLD is characterised by fat accumulation in the liver (hepatic steatosis) with varying degrees of inflammation and fibrosis. MAFLD is strongly linked with cardiometabolic disease and lifestyle-related cancers, in addition to heightened liver-related morbidity and mortality.

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The proliferation of genomic sequencing approaches has significantly impacted the field of phylogenetics. Target capture approaches provide a cost-effective, fast and easily applied strategy for phylogenetic inference of non-model organisms. However, several existing target capture processing pipelines are incapable of incorporating whole genome sequencing (WGS).

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Background: Exercise is a proven therapy for managing cardiometabolic risk factors in type 2 diabetes (T2D). However, its effects on patient-reported outcome measures such as quality of life (QoL) in people with T2D remain unclear. Consequently, the primary aim of this study was to determine the effect of regular exercise on QoL in adults with T2D.

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Females with type 2 diabetes (T2D) have a 25-50% greater risk of developing cardiovascular disease compared with males. While aerobic exercise training is effective for improving cardiometabolic health outcomes, there is limited sex-segregated evidence on the feasibility of aerobic training in adults with T2D. A secondary analysis of a 12-week randomized controlled trial examining aerobic training in inactive adults with T2D was conducted.

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The (https://github.com/pmartR/pmartR) package was designed for the quality control (QC) and analysis of mass spectrometry data, tailored to specific characteristics of proteomic (isobaric or labeled), metabolomic, and lipidomic data sets. Since its initial release, the tool has been expanded to address the needs of its growing userbase and now includes QC and statistics for nuclear magnetic resonance metabolomic data, and leverages the , , and R packages for transcriptomic data analyses.

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Species distribution models (SDMs) are an increasingly important tool for conservation particularly for difficult-to-study locations and with understudied fauna. Our aims were to (1) use SDMs and ensemble SDMs to predict the distribution of freshwater mussels in the Pánuco River Basin in Central México; (2) determine habitat factors shaping freshwater mussel occurrence; and (3) use predicted occupancy across a range of taxa to identify freshwater mussel biodiversity hotspots to guide conservation and management. In the Pánuco River Basin, we modeled the distributions of 11 freshwater mussel species using an ensemble approach, wherein multiple SDM methodologies were combined to create a single ensemble map of predicted occupancy.

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Excess visceral adiposity contributes to elevated cardiometabolic risk, and waist circumference is commonly used as a surrogate measure of visceral adipose tissue. Although regular aerobic exercise is known to improve abdominal obesity, its effect on waist circumference is unclear. A systematic review and meta-analysis was performed to determine (1) the effect of aerobic exercise on waist circumference in adults with overweight or obesity; (2) the association between any change in waist circumference and change in visceral adipose tissue and/or bodyweight with aerobic exercise interventions; and (3) if reductions in waist circumference with exercise are moderated by clinical characteristics or components of aerobic exercise prescription.

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Background: Non-alcoholic fatty liver disease (NAFLD) is predominantly managed by lifestyle intervention, in the absence of effective pharmacotherapies. Mediterranean diet (MedDiet) is the recommended diet, albeit with limited evidence.

Aims: To compare an ad libitum MedDiet to low-fat diet (LFD) in patients with NAFLD for reducing intrahepatic lipids (IHL) by proton magnetic resonance spectroscopy ( H-MRS).

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Background: Cannabidiol (CBD) has demonstrated anti-inflammatory, analgesic, anxiolytic and neuroprotective effects that have the potential to benefit athletes. This pilot study investigated the effects of acute, oral CBD treatment on physiological and psychological responses to aerobic exercise to determine its practical utility within the sporting context.

Methods: On two occasions, nine endurance-trained males (mean ± SD V̇O: 57.

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Background: Polycystic Ovary Syndrome (PCOS), a common endocrine disorder in women of reproductive age, increases the risk for cardiometabolic morbidity. While regular exercise is effective in reducing cardiometabolic risk, women with PCOS may experience condition-specific barriers to exercise thereby limiting its efficacy.

Aim: To determine the effect of exercise on cardiometabolic risk factors in women with PCOS.

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The shell morphologies of the freshwater mussel species (federally endangered) and (species of concern) are similar, causing considerable taxonomic confusion between the two species over the last 100 years. While was historically widespread throughout the Ohio River basin and tributaries to the lower Laurentian Great Lakes, was confined to the Tennessee and the upper Cumberland River basins. We used two mitochondrial DNA (mtDNA) genes, 13 novel nuclear DNA microsatellite markers, and shell morphometrics to help resolve this taxonomic confusion.

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Context: Non-alcoholic fatty liver disease, characterized by excess fat accumulation in the liver, is considered the hepatic manifestation of metabolic syndrome. Recent findings have shown that high-intensity interval training (HIIT) can reduce liver fat but it is unclear whether this form of exercise is superior to traditional moderate-intensity continuous training (MICT).

Objective: The aim of this systematic review was to determine the effect of HIIT vs MICT on liver fat in adults.

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Freshwater mussels are a species-rich group with biodiversity patterns strongly shaped by a life history strategy that includes an obligate parasitic larval stage. In this study, we set out to reconstruct the life history evolution and systematics in a clade of freshwater mussels adapted to parasitizing a molluscivorous host fish. Anchored hybrid enrichment and ancestral character reconstruction revealed a complex pattern of life history evolution with host switching and multiple instances of convergence, including reduction in size of larvae, increased fecundity, and growth during encapsulation.

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This Position Statement examines the evidence for physical activity in weight and adiposity loss, prevention of weight and adiposity gain, and in weight regain in adults, and provides guidance on implications for exercise practitioners. Research evidence indicates that >150 min but preferably 300 min per week of aerobic activity of at least moderate intensity is required to prevent weight and adiposity gain, and at least the upper end of this range of activity to prevent weight regain after weight loss. For meaningful weight and total adiposity loss, a minimum of 300-420 min per week of aerobic activity of at least moderate intensity is required.

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Population genomics has significantly increased our ability to make inferences about microevolutionary processes and demographic histories, which have the potential to improve protection and recovery of imperiled species. Freshwater mussels (Bivalvia: Unionida) represent one of the most imperiled groups of organisms globally. Despite systemic decline of mussel abundance and diversity, studies evaluating spatiotemporal changes in distribution, demographic histories, and ecological factors that threaten long-term persistence of imperiled species remain lacking.

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Background: Exercise-induced improvements in cardiorespiratory fitness (CRF) often coincide with improvements in insulin sensitivity and reductions in liver fat content. However, there are limited data concerning the relationship between CRF and liver fat content in adults with varying degrees of metabolic dysfunction.

Methods: The aim of this study was to examine the association between CRF, liver fat content, and insulin resistance in inactive adults with obesity and with or without type 2 diabetes (T2D), via cross-sectional analysis.

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High-intensity interval training (HIIT) is characterised by short bouts of high-intensity submaximal exercise interspersed with rest periods. Low-volume HIIT, typically involving less than 15 min of high-intensity exercise per session, is being increasingly investigated in healthy and clinical populations due to its time-efficient nature and purported health benefits. The findings from recent trials suggest that low-volume HIIT can induce similar, and at times greater, improvements in cardiorespiratory fitness, glucose control, blood pressure, and cardiac function when compared to more traditional forms of aerobic exercise training including high-volume HIIT and moderate intensity continuous training, despite requiring less time commitment and lower energy expenditure.

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