Publications by authors named "Andrew Gonzalez"

112 Publications

Grand challenges in biodiversity-ecosystem functioning research in the era of science-policy platforms require explicit consideration of feedbacks.

Proc Biol Sci 2021 Oct 13;288(1960):20210783. Epub 2021 Oct 13.

Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, MN, USA.

Feedbacks are an essential feature of resilient socio-economic systems, yet the feedbacks between biodiversity, ecosystem services and human wellbeing are not fully accounted for in global policy efforts that consider future scenarios for human activities and their consequences for nature. Failure to integrate feedbacks in our knowledge frameworks exacerbates uncertainty in future projections and potentially prevents us from realizing the full benefits of actions we can take to enhance sustainability. We identify six scientific research challenges that, if addressed, could allow future policy, conservation and monitoring efforts to quantitatively account for ecosystem and societal consequences of biodiversity change. Placing feedbacks prominently in our frameworks would lead to (i) coordinated observation of biodiversity change, ecosystem functions and human actions, (ii) joint experiment and observation programmes, (iii) more effective use of emerging technologies in biodiversity science and policy, and (iv) a more inclusive and integrated global community of biodiversity observers. To meet these challenges, we outline a five-point action plan for collaboration and connection among scientists and policymakers that emphasizes diversity, inclusion and open access. Efforts to protect biodiversity require the best possible scientific understanding of human activities, biodiversity trends, ecosystem functions and-critically-the feedbacks among them.
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http://dx.doi.org/10.1098/rspb.2021.0783DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8511742PMC
October 2021

SARS-CoV-2 monoclonal antibodies with therapeutic potential: Broad neutralizing activity and No evidence of antibody-dependent enhancement.

Antiviral Res 2021 11 8;195:105185. Epub 2021 Oct 8.

Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA. Electronic address:

Monoclonal antibodies (mAbs) are emerging as safe and effective therapeutics against SARS-CoV-2. However, variant strains of SARS-CoV-2 have evolved, with early studies showing that some mAbs may not sustain their efficacy in the face of escape mutants. Also, from the onset of the COVID-19 pandemic, concern has been raised about the potential for Fcγ receptor-mediated antibody-dependent enhancement (ADE) of infection. In this study, plaque reduction neutralization assays demonstrated that mAb 1741-LALA neutralizes SARS-CoV-2 strains B.1.351, D614 and D614G. MAbs S1D2-hIgG1 and S1D2-LALA mutant (STI-1499-LALA) did not neutralize B.1.351, but did neutralize SARS-CoV-2 strains D614 and D614G. LALA mutations did not result in substantial differences in neutralizing abilities between clones S1D2-hIgG1 vs STI-1499-LALA. S1D2-hIgG1, STI-1499-LALA, and convalescent plasma showed minimal ability to induce ADE in human blood monocyte-derived macrophages. Further, no differences in pharmacokinetic clearance of S1D2-hIgG1 vs STI-1499-LALA were observed in mice expressing human FcRn. These findings confirm that SARS-CoV-2 has already escaped some mAbs, and identify a mAb candidate that may neutralize multiple SARS-CoV-2 variants. They also suggest that risk of ADE in macrophages may be low with SARS-CoV-2 D614, and LALA Fc change impacts neither viral neutralization nor Ab clearance.
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http://dx.doi.org/10.1016/j.antiviral.2021.105185DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8498781PMC
November 2021

A roadmap towards predicting species interaction networks (across space and time).

Philos Trans R Soc Lond B Biol Sci 2021 11 20;376(1837):20210063. Epub 2021 Sep 20.

Sciences Biologiques, Université de Montréal, Montréal, Canada H2V 0B3.

Networks of species interactions underpin numerous ecosystem processes, but comprehensively sampling these interactions is difficult. Interactions intrinsically vary across space and time, and given the number of species that compose ecological communities, it can be tough to distinguish between a true negative (where two species never interact) from a false negative (where two species have not been observed interacting even though they actually do). Assessing the likelihood of interactions between species is an imperative for several fields of ecology. This means that to predict interactions between species-and to describe the structure, variation, and change of the ecological networks they form-we need to rely on modelling tools. Here, we provide a proof-of-concept, where we show how a simple neural network model makes accurate predictions about species interactions given limited data. We then assess the challenges and opportunities associated with improving interaction predictions, and provide a conceptual roadmap forward towards predictive models of ecological networks that is explicitly spatial and temporal. We conclude with a brief primer on the relevant methods and tools needed to start building these models, which we hope will guide this research programme forward. This article is part of the theme issue 'Infectious disease macroecology: parasite diversity and dynamics across the globe'.
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http://dx.doi.org/10.1098/rstb.2021.0063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8450634PMC
November 2021

Resistance, resilience, and functional redundancy of freshwater bacterioplankton communities facing a gradient of agricultural stressors in a mesocosm experiment.

Mol Ecol 2021 10 12;30(19):4771-4788. Epub 2021 Aug 12.

Département des Sciences Biologiques, Université de Montréal, Montreal, QC, Canada.

Agricultural pollution with fertilizers and pesticides is a common disturbance to freshwater biodiversity. Bacterioplankton communities are at the base of aquatic food webs, but their responses to these potentially interacting stressors are rarely explored. To test the extent of resistance and resilience in bacterioplankton communities faced with agricultural stressors, we exposed freshwater mesocosms to single and combined gradients of two commonly used pesticides: the herbicide glyphosate (0-15 mg/L) and the neonicotinoid insecticide imidacloprid (0-60 μg/L), in high or low nutrient backgrounds. Over the 43-day experiment, we tracked variation in bacterial density with flow cytometry, carbon substrate use with Biolog EcoPlates, and taxonomic diversity and composition with environmental 16S rRNA gene amplicon sequencing. We show that only glyphosate (at the highest dose, 15 mg/L), but not imidacloprid, nutrients, or their interactions measurably changed community structure, favouring members of the Proteobacteria including the genus Agrobacterium. However, no change in carbon substrate use was detected throughout, suggesting functional redundancy despite taxonomic changes. We further show that communities are resilient at broad, but not fine taxonomic levels: 24 days after glyphosate application the precise amplicon sequence variants do not return, and tend to be replaced by phylogenetically close taxa. We conclude that high doses of glyphosate - but still within commonly acceptable regulatory guidelines - alter freshwater bacterioplankton by favouring a subset of higher taxonomic units (i.e., genus to phylum) that transiently thrive in the presence of glyphosate. Longer-term impacts of glyphosate at finer taxonomic resolution merit further investigation.
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http://dx.doi.org/10.1111/mec.16100DOI Listing
October 2021

Understanding and finding opportunities for inclusive mentorship and sponsorships in vascular surgery.

J Vasc Surg 2021 08;74(2S):56S-63S

Division of Vascular Surgery, Department of Surgery, University of Washington School of Medicine, Seattle, Wash.

Deliberate efforts are needed to address the lack of diversity in the vascular surgery workforce and to correct the current scarcity of diversity in vascular surgery leadership. Effective mentorship and sponsorship are crucial for success in academic surgery. In the present report, we have explained the importance of mentorship and sponsorship relationships for surgeons historically underrepresented in medicine, discussed the unique challenges faced by them in academic surgery, and provided a practical framework for fostering intentional and thoughtful mentor and sponsor relationships to nurture their careers.
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http://dx.doi.org/10.1016/j.jvs.2021.03.048DOI Listing
August 2021

Widespread agrochemicals differentially affect zooplankton biomass and community structure.

Ecol Appl 2021 10 17;31(7):e02423. Epub 2021 Aug 17.

Department of Biology, McGill University, Montréal, Québec, H3A 1B1, Canada.

Anthropogenic environmental change is causing habitat deterioration at unprecedented rates in freshwater ecosystems. Despite increasing more rapidly than many other agents of global change, synthetic chemical pollution-including agrochemicals such as pesticides-has received relatively little attention in freshwater community and ecosystem ecology. Determining the combined effects of multiple agrochemicals on complex biological systems remains a major challenge, requiring a cross-field integration of ecology and ecotoxicology. Using a large-scale array of experimental ponds, we investigated the response of zooplankton community properties (biomass, composition, and diversity metrics) to the individual and joint presence of three globally widespread agrochemicals: the herbicide glyphosate, the neonicotinoid insecticide imidacloprid, and nutrient fertilizers. We tracked temporal variation in zooplankton biomass and community structure along single and combined pesticide gradients (each spanning eight levels), under low (mesotrophic) and high (eutrophic) nutrient-enriched conditions, and quantified (1) response threshold concentrations, (2) agrochemical interactions, and (3) community resistance and recovery. We found that the biomass of major zooplankton groups differed in their sensitivity to pesticides: ≥0.3 mg/L glyphosate elicited long-lasting declines in rotifer communities, both pesticides impaired copepods (≥3 µg/L imidacloprid and ≥5.5 mg/L glyphosate), whereas some cladocerans were highly tolerant to pesticide contamination. Strong interactive effects of pesticides were only recorded in ponds treated with the combination of the highest doses. Overall, glyphosate was the most influential driver of aggregate community properties of zooplankton, with biomass and community structure responding rapidly but recovering unequally over time. Total community biomass showed little resistance when first exposed to glyphosate, but rapidly recovered and even increased with glyphosate concentration over time; in contrast, taxon richness decreased in more contaminated ponds but failed to recover. Our results indicate that the biomass of tolerant taxa compensated for the loss of sensitive species after the first exposure, conferring greater community resistance upon a subsequent contamination event; a case of pollution-induced community tolerance in freshwater animals. These findings suggest that zooplankton biomass may be more resilient to agrochemical pollution than community structure; yet all community properties measured in this study were affected at glyphosate concentrations below common water quality guidelines in North America.
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http://dx.doi.org/10.1002/eap.2423DOI Listing
October 2021

Predictors of Work Efficiency in Structural Firefighters.

J Occup Environ Med 2021 07;63(7):622-628

Exercise Physiology Laboratory, Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky (Mr Norris, Dr Best, Dr Abel); Department of Health and Human Performance, Texas State University, San Marcos, Texas (Mr Gonzalez, Dr McAllister); Rocky Mountain University of Health Professions, Provo, Utah (Dr Pettitt); H.H. Morris Human Performance Laboratories, Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana (Dr Keeler).

Objective: Develop a novel work efficiency (WE) metric to quantify firefighter physical ability and identify correlates of WE.

Methods: Physical fitness and anthropometric measurements were taken on 19 male firefighters. Firefighters performed a timed maximal effort simulated fireground test (SFGT). WE was quantified as: (1/[Air depletion × SFGT completion time]) × 10,000. Regression analyses were used to identify predictors of WE.

Results: WE was significantly correlated to age, relative body fat, fat mass, occupational experience, jump height, inverted row repetitions, relative bench press and squat strength, treadmill time to exhaustion, relative ventilatory threshold, and relative peak oxygen consumption. Treadmill time to exhaustion and relative lower body strength accounted for the greatest variance in WE (R2 = 0.72, root mean square error = 0.07).

Conclusion: Aerobic endurance and relative lower body strength were related to an occupationally-specific assessment of firefighter physical ability.
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http://dx.doi.org/10.1097/JOM.0000000000002197DOI Listing
July 2021

Correction to: Temperate forest fragments maintain aboveground carbon stocks out to the forest edge despite changes in community composition.

Oecologia 2021 Jul;196(3):935

Department of Biology, McGill University, 1205 Docteur Penfield, Montreal, QC, H3A 1B1, Canada.

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http://dx.doi.org/10.1007/s00442-021-04946-3DOI Listing
July 2021

Biodiversity as insurance: from concept to measurement and application.

Biol Rev Camb Philos Soc 2021 10 2;96(5):2333-2354. Epub 2021 Jun 2.

Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, 1900 Pleasant St., Boulder, CO, 80303, U.S.A.

Biological insurance theory predicts that, in a variable environment, aggregate ecosystem properties will vary less in more diverse communities because declines in the performance or abundance of some species or phenotypes will be offset, at least partly, by smoother declines or increases in others. During the past two decades, ecology has accumulated strong evidence for the stabilising effect of biodiversity on ecosystem functioning. As biological insurance is reaching the stage of a mature theory, it is critical to revisit and clarify its conceptual foundations to guide future developments, applications and measurements. In this review, we first clarify the connections between the insurance and portfolio concepts that have been used in ecology and the economic concepts that inspired them. Doing so points to gaps and mismatches between ecology and economics that could be filled profitably by new theoretical developments and new management applications. Second, we discuss some fundamental issues in biological insurance theory that have remained unnoticed so far and that emerge from some of its recent applications. In particular, we draw a clear distinction between the two effects embedded in biological insurance theory, i.e. the effects of biodiversity on the mean and variability of ecosystem properties. This distinction allows explicit consideration of trade-offs between the mean and stability of ecosystem processes and services. We also review applications of biological insurance theory in ecosystem management. Finally, we provide a synthetic conceptual framework that unifies the various approaches across disciplines, and we suggest new ways in which biological insurance theory could be extended to address new issues in ecology and ecosystem management. Exciting future challenges include linking the effects of biodiversity on ecosystem functioning and stability, incorporating multiple functions and feedbacks, developing new approaches to partition biodiversity effects across scales, extending biological insurance theory to complex interaction networks, and developing new applications to biodiversity and ecosystem management.
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http://dx.doi.org/10.1111/brv.12756DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8519139PMC
October 2021

Emergency Department Utilization and Readmissions Following Major Surgery: A Retrospective Study of Medicare Data.

J Surg Res 2021 09 1;265:187-194. Epub 2021 May 1.

Institute for Healthcare Policy and Innovation, University of Michigan, Ann Arbor, Michigan; Department of Emergency Medicine, University of Michigan, Ann Arbor, Michigan.

Background: Reliable strategies for reducing postoperative readmissions remain elusive. As the emergency department (ED) is a frequent source of post-operative admissions, we investigated whether hospitals with high readmission rates also have high rates of post-discharge ED visits and high rates of readmission once an ED visit occurs.

Methods: We conducted a retrospective analysis of 1,947,621 Medicare beneficiaries undergoing 1 of 5 common procedures in 2,894 hospitals between 2008 and 2011. We stratified hospitals into quintiles based on risk-standardized, 30-day post-discharge readmission rates (RSRR) and then compared rates of post-discharge ED visits, proportion readmitted from the ED, and readmissions within 7 days of ED discharge across these quintiles.

Results: RSRR varied widely across extremes of hospital quintiles (3.9% to 17.5%). Hospitals with either very low or very high RSRR had modest differences in rates of ED visits (12.4% versus 14.6%). In contrast, the proportion readmitted from the ED was nearly 3 times greater in Hospitals with very high RSRR compared with those with very low RSRR (12% versus 32.2%). These findings were consistent across all procedures. Importantly, hospitals with a low proportion readmitted from the ED did not exhibit an increased rate of readmission within 7 days of ED discharge.

Conclusions: Although hospitals experience similar rates of ED visits following major surgery, some EDs and their affiliated surgeons and health system may deliver care preventing readmissions without an increased short-term risk of readmission following ED discharge. Reducing 30-day readmissions requires greater attention to the coordination of care delivered in the ED.
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http://dx.doi.org/10.1016/j.jss.2021.02.052DOI Listing
September 2021

Time Restricted Feeding Reduces Inflammation and Cortisol Response to a Firegrounds Test in Professional Firefighters.

J Occup Environ Med 2021 05;63(5):441-447

Metabolic & Applied Physiology Lab, Department of Health & Human Performance, Texas State University, San Marcos Texas (Dr McAllister, Mr Gonzalez); and Department of Kinesiology, University of North Alabama, Florence, Alabama (Dr Waldman).

Objective: Firefighters are at a heightened risk for developing cardiovascular disease. The purpose of this study was to determine if time restricted feeding (TRF) can improve the stress/inflammatory response to a simulated firegrounds test (FGT) in professional firefighters.

Methods: Thirteen firefighters participated in an 8-week TRF intervention (14:10 [fasting:feeding]) protocol and completed a FGT before and after the intervention. Blood lactate, heart rate, salivary C-reactive protein (CRP), interleukin-6 (IL-6), interleukin 1-β (IL-1β), and cortisol were measured pre and post FGT.

Results: Following TRF, the salivary cortisol response to the FGT was significantly (P < 0.05) reduced. Salivary IL-6 and IL-1β were also significantly lower, and CRP was higher following the intervention.

Conclusions: These findings demonstrate lower inflammation and reduced stress response to FGT following TRF and may suggest implications in terms of cardiometabolic benefits for firefighters.
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http://dx.doi.org/10.1097/JOM.0000000000002169DOI Listing
May 2021

Impact of Time Restricted Feeding on Fitness Variables in Professional Resistance Trained Firefighters.

J Occup Environ Med 2021 04;63(4):343-349

Department of Health & Human Performance, Texas State University, San Marcos, Texas (Mr Gonzalez, Dr McCurdy, Dr McAllister); Department of Kinesiology, University of North Alabama, Florence, Alabama (Dr Waldman); and Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, Kentucky (Dr Abel).

Firefighters are at an elevated risk for cardiometabolic disease and sudden cardiac death due to physiological and psychological stressors. Research suggests time restricted feeding (TRF) may improve health and performance variables.

Objective: This study investigated the effects of a 7-week TRF (14-hour fasting:10-hour eating window) on fitness variables related to physical health and performance among professional, resistance-trained firefighters.

Methods: Several fitness variables were assessed pre- and post-TRF intervention.

Results: Relative and absolute ventilatory threshold (VT) increased (P < 0.05), relative and absolute , decreased (P < 0.05), and muscular strength, endurance, and power were not affected pre- versus post-intervention.

Conclusion: Although , decreased, all other performance variables were not negatively impacted by TRF. Improvements in VT may be associated with improvements to markers of endurance exercise performance in firefighters, but more data are needed to confirm this hypothesis.
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http://dx.doi.org/10.1097/JOM.0000000000002144DOI Listing
April 2021

Refining analyses of existing data sets is valuable for macrogenetics: a response to Paz-Vinas, Jensen et al., (2021).

Ecol Lett 2021 Jun 22;24(6):1285-1286. Epub 2021 Mar 22.

Department of Biology, McGill University, Montreal, QC, Canada.

Paz-Vinas, Jensen et al. (2021) comment on data and methodological limits of Millette, Fugère, Debyser et al. (2020)-some affect a small proportion of our data sets and analyses and others need to be tackled more generally. These points do not refute our main conclusion of no strong signal of human impacts on COI variation globally.
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http://dx.doi.org/10.1111/ele.13733DOI Listing
June 2021

Scaling up biodiversity-ecosystem functioning relationships: the role of environmental heterogeneity in space and time.

Proc Biol Sci 2021 03 10;288(1946):20202779. Epub 2021 Mar 10.

Department of Biology, McGill University, 1205 Dr. Penfield Avenue, Montreal, Quebec, Canada H3A 1B1.

The biodiversity and ecosystem functioning (BEF) relationship is expected to be scale-dependent. The autocorrelation of environmental heterogeneity is hypothesized to explain this scale dependence because it influences how quickly biodiversity accumulates over space or time. However, this link has yet to be demonstrated in a formal model. Here, we use a Lotka-Volterra competition model to simulate community dynamics when environmental conditions vary across either space or time. Species differ in their optimal environmental conditions, which results in turnover in community composition. We vary biodiversity by modelling communities with different sized regional species pools and ask how the amount of biomass per unit area depends on the number of species present, and the spatial or temporal scale at which it is measured. We find that more biodiversity is required to maintain functioning at larger temporal and spatial scales. The number of species required increases quickly when environmental autocorrelation is low, and slowly when autocorrelation is high. Both spatial and temporal environmental heterogeneity lead to scale dependence in BEF, but autocorrelation has larger impacts when environmental change is temporal. These findings show how the biodiversity required to maintain functioning is expected to increase over space and time.
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http://dx.doi.org/10.1098/rspb.2020.2779DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7944106PMC
March 2021

Landscape modification and nutrient-driven instability at a distance.

Ecol Lett 2021 Mar 21;24(3):398-414. Epub 2020 Nov 21.

McGill University, 1205 Dr-Penfield Ave, Montreal, Quebec, H3A 1B1, Canada.

Almost 50 years ago, Michael Rosenzweig pointed out that nutrient addition can destabilise food webs, leading to loss of species and reduced ecosystem function through the paradox of enrichment. Around the same time, David Tilman demonstrated that increased nutrient loading would also be expected to cause competitive exclusion leading to deleterious changes in food web diversity. While both concepts have greatly illuminated general diversity-stability theory, we currently lack a coherent framework to predict how nutrients influence food web stability across a landscape. This is a vitally important gap in our understanding, given mounting evidence of serious ecological disruption arising from anthropogenic displacement of resources and organisms. Here, we combine contemporary theory on food webs and meta-ecosystems to show that nutrient additions are indeed expected to drive loss in stability and function in human-impacted regions. Our models suggest that destabilisation is more likely to be caused by the complete loss of an equilibrium due to edible plant species being competitively excluded. In highly modified landscapes, spatial nutrient transport theory suggests that such instabilities can be amplified over vast distances from the sites of nutrient addition. Consistent with this theoretical synthesis, the empirical frequency of these distant propagating ecosystem imbalances appears to be growing. This synthesis of theory and empirical data suggests that human modification of the Earth is strongly connecting distantly separated ecosystems, causing rapid, expansive and costly nutrient-driven instabilities over vast areas of the planet. Similar to existing food web theory, the corollary to this spatial nutrient theory is that slowing down spatial nutrient pathways can be a potent means of stabilising degraded ecosystems.
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http://dx.doi.org/10.1111/ele.13644DOI Listing
March 2021

CD8 T cells mediate protection against Zika virus induced by an NS3-based vaccine.

Sci Adv 2020 Nov 4;6(45). Epub 2020 Nov 4.

Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA.

Zika virus (ZIKV) is associated with congenital malformations in infants born to infected mothers, and with Guillain-Barré syndrome in infected adults. Development of ZIKV vaccines has focused predominantly on the induction of neutralizing antibodies, although a suboptimal antibody response may theoretically enhance disease severity through antibody-dependent enhancement (ADE). Here, we report induction of a protective anti-ZIKV CD8 T cell response in the HLA-B*0702 transgenic mice using an alphavirus-based replicon RNA vaccine expressing ZIKV nonstructural protein NS3, a potent T cell antigen. The NS3 vaccine did not induce a neutralizing antibody response but elicited polyfunctional CD8 T cells that were necessary and sufficient for preventing death in lethally infected adult mice and fetal growth restriction in infected pregnant mice. These data identify CD8 T cells as the major mediators of ZIKV NS3 vaccine-induced protection and suggest a new strategy to develop safe and effective anti-flavivirus vaccines.
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http://dx.doi.org/10.1126/sciadv.abb2154DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7673678PMC
November 2020

Impact of Time Restricted Feeding on Markers of Cardiometabolic Health and Oxidative Stress in Resistance-Trained Firefighters.

J Strength Cond Res 2020 Oct 30. Epub 2020 Oct 30.

Department of Kinesiology, University of North Alabama, Florence, Alabama.

McAllister, MJ, Gonzalez, AE, and Waldman, HS. Impact of time restricted feeding on markers of cardiometabolic health and oxidative stress in resistance-trained firefighters. J Strength Cond Res XX(X): 000-000, 2020-Firefighters are often exposed to numerous occupational stressors that cause inflammation, oxidative stress (OS), and elevated risk for developing cardiometabolic disease. Time-restricted feeding (TRF) has been shown to result in favorable changes in markers of inflammation and cardiometabolic health. This study investigated the impact of a 6-week TRF intervention (14:10; fasting:feeding) in resistance-trained firefighters. Blood was analyzed for several markers of inflammation, OS, and cardiometabolic health: insulin, ghrelin, leptin, glucagon, adiponectin, resistin, advanced glycated end products (AGE), advanced oxidation protein products, total nitrite-nitrate levels, tumor necrosis factor-α, interleukin (IL)-6, IL-8, IL-10, as well as glucose and lipid levels. A graded exercise test was also conducted before and after the TRF intervention, and substrate oxidation rates were calculated and compared before and after the intervention. Comparisons pre and post TRF were determined with dependent t-tests. Time-restricted feeding resulted in significant reductions in advanced oxidation protein products (∼31%) and AGEs (∼25%); however, no other changes were found. These findings suggest that TRF may be a nutrition intervention aimed at improving some select markers of cardiometabolic health in firefighters, namely, by the reductions in advanced oxidation protein products and AGEs.
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http://dx.doi.org/10.1519/JSC.0000000000003860DOI Listing
October 2020

Life in fluctuating environments.

Philos Trans R Soc Lond B Biol Sci 2020 12 2;375(1814):20190454. Epub 2020 Nov 2.

Department of Biology, Quebec Centre for Biodiversity Science, McGill University, Montreal, Canada H3A 1B1.

Variability in the environment defines the structure and dynamics of all living systems, from organisms to ecosystems. Species have evolved traits and strategies that allow them to detect, exploit and predict the changing environment. These traits allow organisms to maintain steady internal conditions required for physiological functioning through feedback mechanisms that allow internal conditions to remain at or near a set-point despite a fluctuating environment. In addition to feedback, many organisms have evolved feedforward processes, which allow them to adjust in anticipation of an expected future state of the environment. Here we provide a framework describing how feedback and feedforward mechanisms operating within organisms can generate effects across scales of organization, and how they allow living systems to persist in fluctuating environments. Daily, seasonal and multi-year cycles provide cues that organisms use to anticipate changes in physiologically relevant environmental conditions. Using feedforward mechanisms, organisms can exploit correlations in environmental variables to prepare for anticipated future changes. Strategies to obtain, store and act on information about the conditional nature of future events are advantageous and are evidenced in widespread phenotypes such as circadian clocks, social behaviour, diapause and migrations. Humans are altering the ways in which the environment fluctuates, causing correlations between environmental variables to become decoupled, decreasing the reliability of cues. Human-induced environmental change is also altering sensory environments and the ability of organisms to detect cues. Recognizing that living systems combine feedback and feedforward processes is essential to understanding their responses to current and future regimes of environmental fluctuations. This article is part of the theme issue 'Integrative research perspectives on marine conservation'.
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http://dx.doi.org/10.1098/rstb.2019.0454DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7662201PMC
December 2020

Converting Ecological Currencies: Energy, Material, and Information Flows.

Trends Ecol Evol 2020 12 9;35(12):1068-1077. Epub 2020 Sep 9.

Department of Biology, McGill University, Montreal, Quebec, Canada.

Understanding how the three currencies of life - energy, material, and information - interact is a key step towards synthesis in ecology and evolution. However, current theory focuses on the role of matter as a resource and energy, and typically ignores how the same matter can have other important effects as a carrier of information or modifier of the environment. Here we present the hypothesis that the dynamic conversion of matter by organisms among its three currencies mediates the structure and function of ecosystems, and that these effects can even supersede the effects of matter as a resource. Humans are changing the information in the environment and this is altering species interactions and flows of matter within and among ecosystems.
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http://dx.doi.org/10.1016/j.tree.2020.07.014DOI Listing
December 2020

Environmental fluctuations can promote evolutionary rescue in high-extinction-risk scenarios.

Proc Biol Sci 2020 08 5;287(1932):20201144. Epub 2020 Aug 5.

Department of Biology, University of Florida, Gainesville, FL, USA.

Substantial environmental change can force a population onto a path towards extinction, but under some conditions, adaptation by natural selection can rescue the population and allow it to persist. This process, known as evolutionary rescue, is believed to be less likely to occur with greater magnitudes of random environmental fluctuations because environmental variation decreases expected population size, increases variance in population size and increases evolutionary lag. However, previous studies of evolutionary rescue in fluctuating environments have only considered scenarios in which evolutionary rescue was likely to occur. We extend these studies to assess how baseline extinction risk (which we manipulated via changes in the initial population size, degree of environmental change or mutation rate) influences the effects of environmental variation on evolutionary rescue following an abrupt environmental change. Using a combination of analytical models and stochastic simulations, we show that autocorrelated environmental variation hinders evolutionary rescue in low-extinction-risk scenarios but facilitates rescue in high-risk scenarios. In these high-risk cases, the chance of a run of good years counteracts the otherwise negative effects of environmental variation on evolutionary demography. These findings can inform the development of effective conservation practices that consider evolutionary responses to abrupt environmental changes.
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http://dx.doi.org/10.1098/rspb.2020.1144DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7575515PMC
August 2020

Managing central venous access during a health care crisis.

J Vasc Surg 2020 Oct 15;72(4):1184-1195.e3. Epub 2020 Jul 15.

Division of Vascular Surgery, Department of Surgery, Icahn School of Medicine at Mount Sinai, New York, NY.

Objective: During the COVID-19 pandemic, central venous access line teams were implemented at many hospitals throughout the world to provide access for critically ill patients. The objective of this study was to describe the structure, practice patterns, and outcomes of these vascular access teams during the COVID-19 pandemic.

Methods: We conducted a cross-sectional, self-reported study of central venous access line teams in hospitals afflicted with the COVID-19 pandemic. To participate in the study, hospitals were required to meet one of the following criteria: development of a formal plan for a central venous access line team during the pandemic; implementation of a central venous access line team during the pandemic; placement of central venous access by a designated practice group during the pandemic as part of routine clinical practice; or management of an iatrogenic complication related to central venous access in a patient with COVID-19.

Results: Participants from 60 hospitals in 13 countries contributed data to the study. Central venous line teams were most commonly composed of vascular surgery and general surgery attending physicians and trainees. Twenty sites had 2657 lines placed by their central venous access line team or designated practice group. During that time, there were 11 (0.4%) iatrogenic complications associated with central venous access procedures performed by the line team or group at those 20 sites. Triple lumen catheters, Cordis (Santa Clara, Calif) catheters, and nontunneled hemodialysis catheters were the most common types of central venous lines placed by the teams. Eight (14%) sites reported experience in placing central venous lines in prone, ventilated patients with COVID-19. A dedicated line cart was used by 35 (59%) of the hospitals. Less than 50% (24 [41%]) of the participating sites reported managing thrombosed central lines in COVID-19 patients. Twenty-three of the sites managed 48 iatrogenic complications in patients with COVID-19 (including complications caused by providers outside of the line team or designated practice group).

Conclusions: Implementation of a dedicated central venous access line team during a pandemic or other health care crisis is a way by which physicians trained in central venous access can contribute their expertise to a stressed health care system. A line team composed of physicians with vascular skill sets provides relief to resource-constrained intensive care unit, ward, and emergency medicine teams with a low rate of iatrogenic complications relative to historical reports. We recommend that a plan for central venous access line team implementation be in place for future health care crises.
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http://dx.doi.org/10.1016/j.jvs.2020.06.112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7362805PMC
October 2020

Prevalence and associations of incidental nonvenous duplex findings discovered during lower extremity venous imaging.

J Vasc Surg Venous Lymphat Disord 2021 01 27;9(1):200-208. Epub 2020 Jun 27.

Department of Surgery, Center for Outcomes Research in Surgery, Indiana University School of Medicine, Indianapolis, Ind.

Objective: Venous duplex imaging defines venous pathology (VP). Unexpected clinically relevant findings are also found but rarely mentioned in the literature. This study aims to define the prevalence of ancillary findings (nonvenous duplex) by study type and venous outcome and subgroup associations with primary study indication and risk factors.

Methods: Our vascular laboratory database was queried for lower extremity venous duplex studies with comments regarding ancillary findings and associated patient demographics, primary study indication, associated conditions, and venous study outcome.

Results: There were 52,215 venous studies performed, 48,425 to evaluate for venous occlusion (acute/chronic) and 3790 for venous reflux. Of these studies, 15,810 found VP and 36,405 found no venous disease. There were 875 studies with venous disease that had ancillary duplex findings (5.5%) noted as 559 (3.5%) with prominent lymph node(s) (LN), 179 (1.1%) Baker's cyst (BC), 44 (0.3%) hematoma/mass (HM), 31 (0.2%) arterial aneurysm, and 16 (0.1%) arterial occlusion. There were 3130 studies free of VP with ancillary findings (8.6%) noted as 2258 (6.2%) prominent LN(s), 626 (1.7%) BC, 156 (0.4%) HM, 37 (0.1%) arterial aneurysm, and 22 (0.06%) arterial occlusion. The overall prevalence of ancillary findings was 8.62%. Analysis demonstrated statistically more ancillary findings in venous occlusion (odds ratio [OR], 1.25) studies, which was the largest group at 13 to 1. Studies free of venous disease had more ancillary findings (P < .001) with an OR of 1.88 and similar results were noted for LN(s), BC, and hematoma. Studies with VP favored a finding of aneurysm (OR, 0.52). Subgroup analyses demonstrated that those with prominent LN(s) were statistically older and male and BC statistically older in those with coexistent venous disease. BC subgroup analysis showed that studies free of venous disease were 2.5 times more likely to report pain as the primary study indication (P < .0001). In general, within ancillary subgroups, leg symptoms were statistically more prominent on the side with ancillary pathology and free of venous disease.

Conclusions: Ancillary findings are not uncommon and are more common in studies found free of VP. The most common are LNs, BC and HM and, within subgroups, significant leg symptoms favors the presence of ancillary findings without coexisting venous disease. Ancillary findings should be an integral part of a quality report.
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http://dx.doi.org/10.1016/j.jvsv.2020.06.013DOI Listing
January 2021

Breaking ecological barriers: Anthropogenic disturbance leads to habitat transitions, hybridization, and high genetic diversity.

Sci Total Environ 2020 Oct 10;740:140046. Epub 2020 Jun 10.

Department of Biology, McGill University, Montreal, Quebec H3A 1B1, Canada; Quebec Centre for Biodiversity Science, Canada.

Genetic diversity is expected to erode in disturbed habitats through strong selection, local extinctions, and recolonization associated with genetic bottlenecks and restricted gene flow. Despite this general prediction and over three decades of population genetics studies, our understanding of the long-term effect of environmental disturbance on local and regional genetic diversity remains limited. We conducted a population genetic survey of the microcrustacean Daphnia across a landscape subject to anthropogenic stressors from a century of industrial mining. At the local scale we found moderate genetic diversity (i.e., low clonal diversity), characteristic of habitat-specific selective sweeps and local extinctions, but high diversity and strong genetic structure at the regional scale despite the shared watershed of many lakes and exceptional dispersal ability of daphniids. Many habitats experienced changes in species assemblages, with the obligate asexual Daphnia pulex lineages-known only to inhabit ponds-dominating disrupted urban lakes. This habitat transition (pond to lake) was likely facilitated by the disruption of ecological barriers maintaining the genomic separation of these young species. Thus, disrupted habitats can exhibit complex and unexpected genetic patterns of local extinctions and recolonizations, followed by habitat transitions, hybridization and potential speciation events that are difficult to predict and should not be underestimated.
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http://dx.doi.org/10.1016/j.scitotenv.2020.140046DOI Listing
October 2020

Comparison of multi-parallel qPCR and double-slide Kato-Katz for detection of soil-transmitted helminth infection among children in rural Bangladesh.

PLoS Negl Trop Dis 2020 04 24;14(4):e0008087. Epub 2020 Apr 24.

Division of Epidemiology & Biostatistics, University of California, Berkeley, Berkeley, California, United States of America.

There is growing interest in local elimination of soil-transmitted helminth (STH) infection in endemic settings. In such settings, highly sensitive diagnostics are needed to detect STH infection. We compared double-slide Kato-Katz, the most commonly used copromicroscopic detection method, to multi-parallel quantitative polymerase chain reaction (qPCR) in 2,799 stool samples from children aged 2-12 years in a setting in rural Bangladesh with predominantly low STH infection intensity. We estimated the sensitivity and specificity of each diagnostic using Bayesian latent class analysis. Compared to double-slide Kato-Katz, STH prevalence using qPCR was almost 3-fold higher for hookworm species and nearly 2-fold higher for Trichuris trichiura. Ascaris lumbricoides prevalence was lower using qPCR, and 26% of samples classified as A. lumbricoides positive by Kato-Katz were negative by qPCR. Amplicon sequencing of the 18S rDNA from 10 samples confirmed that A. lumbricoides was absent in samples classified as positive by Kato-Katz and negative by qPCR. The sensitivity of Kato-Katz was 49% for A. lumbricoides, 32% for hookworm, and 52% for T. trichiura; the sensitivity of qPCR was 79% for A. lumbricoides, 93% for hookworm, and 90% for T. trichiura. Specificity was ≥ 97% for both tests for all STH except for Kato-Katz for A. lumbricoides (specificity = 68%). There were moderate negative, monotonic correlations between qPCR cycle quantification values and eggs per gram quantified by Kato-Katz. While it is widely assumed that double-slide Kato-Katz has few false positives, our results indicate otherwise and highlight inherent limitations of the Kato-Katz technique. qPCR had higher sensitivity than Kato-Katz in this low intensity infection setting.
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http://dx.doi.org/10.1371/journal.pntd.0008087DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7202662PMC
April 2020

Community rescue in experimental phytoplankton communities facing severe herbicide pollution.

Nat Ecol Evol 2020 04 2;4(4):578-588. Epub 2020 Mar 2.

Department of Biology, McGill University, Montreal, Québec, Canada.

Community rescue occurs when ecological or evolutionary processes restore positive growth in a highly stressful environment that was lethal to the community in its ancestral form, thus averting biomass collapse in a deteriorating environment. Laboratory evidence suggests that community rescue is most likely in high-biomass communities that have previously experienced moderate doses of sublethal stress. We assessed this result under more natural conditions, in a mesocosm experiment with phytoplankton communities exposed to the ubiquitous herbicide glyphosate. We tested whether community biomass and prior herbicide exposure would facilitate community rescue after severe contamination. We found that prior exposure to glyphosate was a very strong predictor of the rescue outcome, while high community biomass was not. Furthermore, although glyphosate had negative effects on diversity, it did not influence community composition significantly, suggesting a modest role for genus sorting in this rescue process. Our results expand the scope of community rescue theory to complex ecosystems and confirm that prior stress exposure is a key predictor of rescue.
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http://dx.doi.org/10.1038/s41559-020-1134-5DOI Listing
April 2020

Scaling-up biodiversity-ecosystem functioning research.

Ecol Lett 2020 Apr 29;23(4):757-776. Epub 2020 Jan 29.

Centre for Biodiversity Theory and Modelling, Theoretical and Experimental Ecology Station, CNRS, 2 route du CNRS, 09200, Moulis, France.

A rich body of knowledge links biodiversity to ecosystem functioning (BEF), but it is primarily focused on small scales. We review the current theory and identify six expectations for scale dependence in the BEF relationship: (1) a nonlinear change in the slope of the BEF relationship with spatial scale; (2) a scale-dependent relationship between ecosystem stability and spatial extent; (3) coexistence within and among sites will result in a positive BEF relationship at larger scales; (4) temporal autocorrelation in environmental variability affects species turnover and thus the change in BEF slope with scale; (5) connectivity in metacommunities generates nonlinear BEF and stability relationships by affecting population  synchrony at local and regional scales; (6) spatial scaling in food web structure and diversity will generate scale dependence in ecosystem functioning. We suggest directions for synthesis that combine approaches in metaecosystem and metacommunity ecology and integrate cross-scale feedbacks. Tests of this theory may combine remote sensing with a generation of networked experiments that assess effects at multiple scales. We also show how anthropogenic land cover change may alter the scaling of the BEF relationship. New research on the role of scale in BEF will guide policy linking the goals of managing biodiversity and ecosystems.
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http://dx.doi.org/10.1111/ele.13456DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7497049PMC
April 2020

What does soil-transmitted helminth elimination look like? Results from a targeted molecular detection survey in Japan.

Parasit Vectors 2020 Jan 8;13(1). Epub 2020 Jan 8.

Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan.

Background: Japan is one of the few countries believed to have eliminated soil-transmitted helminths (STHs). In 1949, the national prevalence of Ascaris lumbricoides was 62.9%, which decreased to 0.6% in 1973 due to improvements in infrastructure, socioeconomic status, and the implementation of national STH control measures. The Parasitosis Prevention Law ended in 1994 and population-level screening ceased in Japan; therefore, current transmission status of STH in Japan is not well characterized. Sporadic cases of STH infections continue to be reported, raising the possibility of a larger-scale recrudescence of STH infections. Given that traditional microscopic detection methods are not sensitive to low-intensity STH infections, we conducted targeted prevalence surveys using sensitive PCR-based assays to evaluate the current STH-transmission status and to describe epidemiological characteristics of areas of Japan believed to have achieved historical elimination of STHs.

Methods: Stool samples were collected from 682 preschool- and school-aged children from six localities of Japan with previously high prevalence of STH. Caregivers of participants completed a questionnaire to ascertain access to water, sanitation and hygiene (WASH), and potential exposures to environmental contamination. For fecal testing, multi-parallel real-time PCR assays were used to detect infections of Ascaris lumbricoides, Necator americanus, Ancylostoma duodenale and Trichuris trichiura.

Results: Among the 682 children, no positive samples were identified, and participants reported high standards of WASH.

Conclusions: To our knowledge, this is the first STH-surveillance study in Japan to use sensitive molecular techniques for STH detection. The results suggest that recrudescence of STH infections has not occurred, and that declines in prevalence have been sustained in the sampled areas. These findings suggest that reductions in prevalence below the elimination thresholds, suggestive of transmission interruption, are possible. Additionally, this study provides circumstantial evidence that multi-parallel real-time PCR methods are applicable for evaluating elimination status in areas where STH prevalence is extremely low.
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http://dx.doi.org/10.1186/s13071-019-3875-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6950881PMC
January 2020

Acute coffee ingestion with and without medium-chain triglycerides decreases blood oxidative stress markers and increases ketone levels.

Can J Physiol Pharmacol 2020 Apr 5;98(4):194-200. Epub 2019 Nov 5.

School of Health Studies, University of Memphis, Memphis, TN 38152, USA.

Ingestion of ketone supplements, caffeine, and medium-chain triglycerides (MCTs) may all be effective strategies to increase blood levels of the ketone body beta-hydroxybutyrate (D-BHB). However, acute ingestion of a bolus of lipids may increase oxidative stress (OS). The purpose of the study was to investigate the impact of adding varying amounts of MCTs to coffee on blood levels of D-BHB and markers of OS. Ten college-aged men ingested coffee with 0, 28, and 42 g of MCT in a randomized order. Blood samples were collected pre- as well as 2 and 4 h postprandial and analyzed for D-BHB, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), glucose, triglycerides (TAG), insulin, and OS markers: advanced oxidation protein products (AOPP), glutathione (GSH), malondialdehyde (MDA), and hydrogen peroxide (HO). All three treatments resulted in a significant increase in D-BHB, HDL-c, and TC as well as a significant decrease in TAG, MDA, HO, and insulin. The 42 g treatment was associated with significantly higher levels of AOPP and MDA. Acute ingestion of coffee results in favorable changes to markers of cardiometabolic health that were not impacted by the addition of 28 g of MCT. However, 42 g of MCT caused significantly greater OS.
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http://dx.doi.org/10.1139/cjpp-2019-0458DOI Listing
April 2020

No consistent effects of humans on animal genetic diversity worldwide.

Ecol Lett 2020 Jan 21;23(1):55-67. Epub 2019 Oct 21.

Department of Biology, McGill University, Montreal, QC, Canada.

Human impacts on genetic diversity are poorly understood yet critical to biodiversity conservation. We used 175 247 COI sequences collected between 1980 and 2016 to assess the global effects of land use and human density on the intraspecific genetic diversity of 17 082 species of birds, fishes, insects and mammals. Human impacts on mtDNA diversity were taxon and scale-dependent, and were generally weak or non-significant. Spatial analyses identified weak latitudinal diversity gradients as well as negative effects of human density on insect diversity, and negative effects of intensive land use on fish diversity. The observed effects were predominantly associated with species turnover. Time series analyses found nearly an equal number of positive and negative temporal trends in diversity, resulting in no net monotonic trend in diversity over this time period. Our analyses reveal critical data and theory gaps and call for increased efforts to monitor global genetic diversity.
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http://dx.doi.org/10.1111/ele.13394DOI Listing
January 2020

The geography of biodiversity change in marine and terrestrial assemblages.

Science 2019 10;366(6463):339-345

Centre for Biological Diversity, School of Biology, University of St. Andrews, St. Andrews, UK.

Human activities are fundamentally altering biodiversity. Projections of declines at the global scale are contrasted by highly variable trends at local scales, suggesting that biodiversity change may be spatially structured. Here, we examined spatial variation in species richness and composition change using more than 50,000 biodiversity time series from 239 studies and found clear geographic variation in biodiversity change. Rapid compositional change is prevalent, with marine biomes exceeding and terrestrial biomes trailing the overall trend. Assemblage richness is not changing on average, although locations exhibiting increasing and decreasing trends of up to about 20% per year were found in some marine studies. At local scales, widespread compositional reorganization is most often decoupled from richness change, and biodiversity change is strongest and most variable in the oceans.
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http://dx.doi.org/10.1126/science.aaw1620DOI Listing
October 2019
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