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Cannon SA, Mintz JA, Roberts BM, Rushing KA, Jenkins GW, Fisher G, Plaisance EP, Morris CE. Evaluation of the Effectiveness of ROTC Army Cadet Exercise Training for the Army Combat Fitness Test. Int J Exerc Sci 2024; 17:172-182. [PMID: 38665851 PMCID: PMC11042889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
The Army Combat Fitness Test (ACFT) is used to evaluate the fitness level of potential Cadets for military readiness. The purpose of this study was to evaluate the effectiveness of the exercise training program implemented by an Army Reserve Officers' Training Corps (ROTC) program to gauge the performance metrics of the ACFT. METHODS Twenty-six student Cadets of the ROTC at the University of Alabama at Birmingham (UAB) program participated in the study. Over an 8-month period, the ROTC Cadets trained on campus three days per week. Training was performed in a circuit training format and each participant cycled through each of the four training stations (Strength, Conditioning, Core, and Endurance) for 15 minutes each session (for a total training time of 60 minutes). Each Cadet had body mass and body composition assessed as well as each component of the ACFT [maximum dead lift (MDL), standing power throw (SPT), hand release push-up (HRP), sprint-drag-carry (SDC), leg tuck/plank (LTK/PLK), and 2-mile run (2MR)]. Each variable was evaluated at three time points (pre-, mid-, and post-training program). RESULTS There was a significant difference in the 2MR score between time points [F(2,50) = 4.530, p = .016, η2 = 0.153] with a significant difference between time point at pre- and post-training (p = .02). No other variables displayed a significant change: body mass (p = .741), body fat percentage (p = .238), MDL (p = .061), SPT (p = .308), HRP (p = .126), SDC (p = 0.132), LTK/PLK (p = 0.583). CONCLUSION The results of this study suggest that the short-term training program used improves 2MR, but not other components of the ACFT over the course of an academic year.
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Affiliation(s)
- Simone A Cannon
- Department of Human Studies, University of Alabama at Birmingham; Birmingham, AL, USA
| | - Jake A Mintz
- Center for Exercise Medicine, University of Alabama at Birmingham; Birmingham, AL, USA
| | - Brandon M Roberts
- Department of Human Studies, University of Alabama at Birmingham; Birmingham, AL, USA
| | - Kelsey A Rushing
- Division of Food, Nutrition, and Exercise Sciences, University of Missouri
| | - Gregor W Jenkins
- Department of Human Studies, University of Alabama at Birmingham; Birmingham, AL, USA
| | - Gordon Fisher
- Department of Human Studies, University of Alabama at Birmingham; Birmingham, AL, USA
| | - Eric P Plaisance
- Department of Nutrition Sciences, University of Alabama at Birmingham; Birmingham, AL, USA
| | - Cody E Morris
- Department of Human Studies, University of Alabama at Birmingham; Birmingham, AL, USA
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Morris CE, Cannon SA, Mintz JA, Rushing KA, Roberts BM, Jenkins GW, Fisher G, Plaisance EP. EVALUATION OF THE EFFECTIVENESS OF ROTC ARMY CADET EXERCISE TRAINING FOR THE ARMY COMBAT FITNESS TEST. Med Sci Sports Exerc 2022. [DOI: 10.1249/01.mss.0000881080.42160.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
ABSTRACT Morris, CE, Arnett, SW, and Winchester, LJ. Comparing physical fitness in career vs. volunteer firefighters. J Strength Cond Res 36(5): 1304-1309, 2022-The purpose of this study was to assess the potential similarities and differences in health and physical fitness profiles between career firefighters (CFF) and volunteer firefighters (VFF). The research protocol consisted of a health and physical fitness assessment, testing the 5 components of health-related fitness using previously published and accepted protocols. The subject population consisted of a total of 138 firefighters, including 119 CFF and 19 VFF. Statistical significance was defined as a p level less than 0.05. An independent t test showed evidence of CFF having a significantly higher value/score for the following variables: height (p = 0.034), V̇o2max (p = 0.006), push-ups completed (p = 0.024), and plank time (p < 0.001). Volunteer firefighters had a significantly higher value for the following variables: fat mass (p = 0.002), body fat percentage (p < 0.001), and absolute grip strength (p = 0.029). There were no significant differences between groups for the following variables: age (p = 0.299), body mass (p = 0.166), fat-free mass (p = 0.281), body mass index (p = 0.057), flexibility (p = 0.106), or relative grip strength (p = 0.887). With regard to physical fitness testing, the VFF had a significantly worse fitness profile across a number of variables than the CFF. Practical applications: Despite the financial and commitment status of volunteer firefighting departments, their members perform an equally dangerous and important job as do firefighters of professional/career firefighting departments, and more attention should be directed toward developing the fitness and performance of these firefighters.
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Affiliation(s)
- Cody E Morris
- Department of Human Studies, University of Alabama at Birmingham, Birmingham, Alabama
| | - Scott W Arnett
- School of Kinesiology, Recreation & Sport, Western Kentucky University, Bowling Green, Kentucky; and
| | - Lee J Winchester
- Department of Kinesiology, the University of Alabama, Tuscaloosa, Alabama
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Winchester LJ, Morris CE, Badinger J, Wiczynski TL, VanWye WR. Blood Flow Restriction at High Resistance Loads Increases the Rate of Muscular Fatigue, but Does Not Increase Plasma Markers of Myotrauma or Inflammation. J Strength Cond Res 2020; 34:2419-2426. [PMID: 32740287 DOI: 10.1519/jsc.0000000000003742] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Winchester, LJ, Morris, CE, Badinger, J, Wiczynski, TL, and VanWye, WR. Blood flow restriction at high resistance loads increases the rate of muscular fatigue, but does not increase plasma markers of myotrauma or inflammation. J Strength Cond Res 34(9): 2419-2426, 2020-High-load resistance training and blood flow restriction (BFR) training at low loads both promote protein synthesis and growth through different cell signaling mechanisms. Therefore, co-activation of these pathways could result in a synergistic effect for additional growth enhancement. The purpose of this study was to evaluate how BFR effects performance and physiological responses after an acute bout of high-load barbell squat training. Twelve resistance-trained, college-aged men and women performed 5 sets of barbell squats at 75% of 1 repetition maximum until failure under traditional (TRAD; control) or intermittent BFR conditions. Perceived limb pain and number of repetitions performed were recorded after each set. Blood samples were collected at baseline and 1-hour postexercise after each trial for analysis of myoglobin and interleukin-6 (IL-6). An alpha level of p < 0.05 was used to determine significance. Blood flow restriction trial performance significantly declined at set 3 and was lower than performance during control, whereas control performance did not decrease until set 5. Perceived limb pain was statistically increased with BFR use for the whole trial and was significantly higher with BFR during set 3 than observed during TRAD. Plasma myoglobin and IL-6 were significantly increased after both trials when compared with baseline, but were not significantly different between trials. Intermittent BFR use during high-load barbell squats increases the rate of muscular fatigue and perceived limb pain, but does not increase muscular damage or inflammatory response. Data obtained from this study can be used by fitness professionals as a means of potentially enhancing the rate of muscular hypertrophy.
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Affiliation(s)
- Lee J Winchester
- Department of Kinesiology, University of Alabama, Tuscaloosa, Alabama
| | - Cody E Morris
- Department of Human Studies, University of Alabama at Birmingham, Birmingham, Alabama
| | - Joseph Badinger
- School of Kinesiology, Western Kentucky University, Bowling Green, Kentucky; and
| | - Teresa L Wiczynski
- School of Kinesiology, Western Kentucky University, Bowling Green, Kentucky; and
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Morris CE, Arnett SW. Physical Fitness Maintenance In Members Of A Southeastern United States City Professional Firefighting Department. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000677824.09630.02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Chander H, Turner AJ, Swain JC, Sutton PE, McWhirter KL, Morris CE, Knight AC, Carruth DW. Impact of occupational footwear and workload on postural stability in work safety. Work 2019; 64:817-824. [DOI: 10.3233/wor-193043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Harish Chander
- Department of Kinesiology, Neuromechanics Laboratory, Mississippi State University, Mississippi State, MS, USA
| | - Alana J. Turner
- Department of Kinesiology, Neuromechanics Laboratory, Mississippi State University, Mississippi State, MS, USA
| | - Jonathan C. Swain
- Department of Health, Physical Education and Recreation, University of North Alabama, Florence, AL, USA
| | - Phillip E. Sutton
- Department of Kinesiology, Neuromechanics Laboratory, Mississippi State University, Mississippi State, MS, USA
| | - Katherine L. McWhirter
- Department of Kinesiology, Neuromechanics Laboratory, Mississippi State University, Mississippi State, MS, USA
| | - Cody E. Morris
- Department of Human Studies, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Adam C. Knight
- Department of Kinesiology, Neuromechanics Laboratory, Mississippi State University, Mississippi State, MS, USA
| | - Daniel W. Carruth
- Human Performance Laboratory, Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS, USA
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Morris CE, Wessel PA, Tinius RA, Schafer MA, Maples JM. Validity of Activity Trackers in Estimating Energy Expenditure During High-Intensity Functional Training. Res Q Exerc Sport 2019; 90:377-384. [PMID: 31046630 DOI: 10.1080/02701367.2019.1603989] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 03/29/2019] [Indexed: 06/09/2023]
Abstract
Purpose: The purpose of this study was to evaluate the agreement of five commercially available accelerometers in estimating energy expenditure while performing an acute bout of high-intensity functional training (HIFT). Methods: Participants (n = 47; average age: 28.5 ± 11.6 years) consisted of recreationally active, healthy adults. Each participant completed a session of HIFT: a 15-minute workout consisting of 12 repetitions each of air-squats, sit-ups, push-ups, lunges, pull-ups, steps-ups, and high-knees; performed circuit-style by completing as many rounds as possible. During this session, each participant wore the Cosmed K4b2 portable metabolic analyzer (PMA) and five different accelerometers (ActiGraph GT3X, Nike Fuelband, Fitbit One, Fitbit Charge HR, and Jawbone UP Move). Results: Four of the five activity trackers reported lower (p < .05) total EE values compared to the PMA during the acute bout of HIFT. The waist-mounted device (ActiGraph, 182.55 ± 37.93 kcal) was not significantly different from, and most closely estimated caloric expenditure compared to the PMA (144.99 ± 37.13 kcal) (p = .056). A repeated-measures ANOVA showed that all activity trackers were significantly different from the reference measure (PMA) (p < .05). Systematic relative agreement between the activity trackers was calculated, exhibiting a significant ICC = 0.426 (F [46,230] = 5.446 [p < .05]). Conclusion: The wrist- and hip-mounted activity trackers did not accurately assess energy expenditure during HIFT exercise. With the exception of the ActiGraph GT3X, the remaining four activity trackers showed inaccurate estimates of the amount of kilocalories expended during the HIFT exercise bout compared to the PMA.
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Morris CE, Arnett SW, Jackson AJ, Winchester LJ. Comparing Physical Fitness in Career vs. Voluntary Firefighters. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000561311.12101.f8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Alvis ML, Morris CE, Garrard TL, Hughes AG, Hunt L, Koester MM, Yocum IC, Tinius RA. Educational Brochures Influence Beliefs and Knowledge Regarding Exercise during Pregnancy: A Pilot Study. Int J Exerc Sci 2019; 12:581-589. [PMID: 31156748 PMCID: PMC6533107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Women who are pregnant report receiving little or no advice about physical activity during pregnancy from their obstetric provider. The purpose of this study was to assess the effectiveness of an evidence-based educational brochure on both immediate and two-week retention of knowledge about exercise during pregnancy. Thirty-two women of childbearing age (age: 25.0 ± 4.0 years, body mass index: 29.5 ± 6.5 kg/m2, 93.7% Caucasian, 83.4% had at least some college) completed a survey before exposure to an evidence-based educational brochure regarding exercise during pregnancy. Post surveys were taken immediately after viewing the educational brochure and again 2-weeks later. After exposure to educational brochures, survey scores on both surveys were significantly higher immediately-post and two-weeks post compared to baseline survey scores (Survey 1 (assessing beliefs) - pre: 79.2 ± 8.9%, post: 92.6 ± 7.4%, 2-weeks post: 92.0 ± 6.5%, p < 0.001; Survey 2 (assessing knowledge) - pre: 65.3 ± 16.4%, post: 81.3 ± 14.9%, 2-weeks post: 78.8 ± 12.4%, p < 0.001). No significant differences detected between immediate post and 2-weeks post for either Survey 1 (p = 0.72) or Survey 2 (p = 0.52); suggesting the information was retained. An evidence-based educational brochure is effective for improving and retaining information 2-weeks later regarding exercise during pregnancy. However, replication studies in more diverse populations are needed to confirm the results of this pilot study. The long-term goal for this line of research is to urge health care providers to consider providing patients with educational information in order to improve knowledge and patient-provider communication on this topic.
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Affiliation(s)
- Madison L Alvis
- School of Kinesiology, Recreation & Sport, Western Kentucky University, Bowling Green, KY, USA
| | - Cody E Morris
- Department of Human Studies, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tiana L Garrard
- School of Kinesiology, Recreation & Sport, Western Kentucky University, Bowling Green, KY, USA
| | - Abigail G Hughes
- School of Kinesiology, Recreation & Sport, Western Kentucky University, Bowling Green, KY, USA
| | - Laura Hunt
- School of Kinesiology, Recreation & Sport, Western Kentucky University, Bowling Green, KY, USA
| | - Megan M Koester
- School of Kinesiology, Recreation & Sport, Western Kentucky University, Bowling Green, KY, USA
| | - India C Yocum
- School of Kinesiology, Recreation & Sport, Western Kentucky University, Bowling Green, KY, USA
| | - Rachel A Tinius
- School of Kinesiology, Recreation & Sport, Western Kentucky University, Bowling Green, KY, USA
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Morris CE, Winchester LJ, Jackson AJ, Tomes AS, Neal WA, Wilcoxen DM, Chander H, Arnett SW. Effect of a simulated tactical occupation task on physiological strain index, stress and inflammation. International Journal of Occupational Safety and Ergonomics 2018; 26:204-209. [DOI: 10.1080/10803548.2018.1482053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Cody E. Morris
- School of Kinesiology, Recreation & Sport, Western Kentucky University, USA
| | - Lee J. Winchester
- School of Kinesiology, Recreation & Sport, Western Kentucky University, USA
| | - Andrew J. Jackson
- School of Kinesiology, Recreation & Sport, Western Kentucky University, USA
| | - Ariel S. Tomes
- School of Kinesiology, Recreation & Sport, Western Kentucky University, USA
| | - Wesley A. Neal
- School of Kinesiology, Recreation & Sport, Western Kentucky University, USA
| | - Damon M. Wilcoxen
- School of Kinesiology, Recreation & Sport, Western Kentucky University, USA
| | - Harish Chander
- Department of Kinesiology, Mississippi State University, USA
| | - Scott W. Arnett
- School of Kinesiology, Recreation & Sport, Western Kentucky University, USA
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Morris CE, Winchester LJ, Hussey AJ, Tomes AS, Neal WA, Wilcoxen DM, Anderson MN, Bradshaw WJ, Lucas DN, Chander H, Arnett SW. Effect of a Simulated Tactical Occupation Stressor on Physiological Strain Index and Blood Pressure. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000538411.89265.f9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Tomes AS, Morris CE, Winchester L, Hussey AJ, Neal WA, Wilcoxen DM, Anderson MN, Bradshaw WJ, Lucas DN, Chander H, Arnett SW. Effect of a Simulated Tactical Occupation Stressor on Immune System Markers of Physiological Stress and Inflammation. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000538413.35007.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Neal WA, Morris CE, Winchester LJ, Hussey AJ, Tomes AS, Wilcoxen DM, Anderson MN, Lucas DN, Chanders H, Arnett SW. Effect of a Simulated Tactical Occupation Stressor on Perceived Exertion and Blood Lactate. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000538412.96889.48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hussey AJ, Morris CE, Winchester LJ, Tomes AS, Neal WA, Wilcoxen DM, Anderson MN, Bradshaw WJ, Lucas DN, Chander H, Arnett SW. Effect of a Simulated Tactical Occupation Stressor on Reaction Time. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000538414.42631.8a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hall AT, Morris CE, Forsythe S, Jordan T, Schafer MA, Wiczynki TL, Upright P. Evaluation Of The Health And Physical Fitness And Factors Influencing Retention Of Scholastic Sports Officials In The Sport Of American Football. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000535647.73289.c7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wiczynski T, Badinger J, Morris CE, VanWye R, Arnett S, Winchester LJ. Blood Flow Restriction During Barbell Squats does not Alter Performance or Muscular Damage. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000535146.02970.fc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Morris CE, Garner JC, Owens SG, Valliant MW, Debusk H, Loftin M. A Prospective Study Comparing Distance-based vs. Time-based Exercise Prescriptions of Walking and Running in Previously Sedentary Overweight Adults. Int J Exerc Sci 2017; 10:782-797. [PMID: 28966715 PMCID: PMC5609661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Prior work has reported that the declines observed in body mass index (BMI) and circumference measurements in their cross-sectional data were twice as large when calculated from distance energy expenditure estimations compared to energy expenditure estimations based on time and intensity. The primary purpose of this study was to compare walking/running for distance to walking/running for time as part of an exercise intervention. This study followed a between-subjects, repeated measures design. Fifteen overweight, but otherwise healthy participants completed the study. The time-based group walked/ran for self-reported time while the distance-based group walked/ran for self-reported distance. A mixed-factor repeated-measures ANOVA was used to compare all dependent variables both within-subjects and between-subjects. Weekly adherence rates to the exercise program did not exhibit a significant difference (p > 0.05). Significant interactions were shown for mean body mass loss between groups as well as mean blood glucose level (p < 0.05). Distance-based group exhibited a decline in body mass and blood glucose while the time-based group exhibited an increase in both variables. To the best of the authors' knowledge, the present study is the first to directly compare a distance-based vs. a time-based exercise program for walking and running for improvement of risk factors of cardiovascular disease. The results of this study would suggest that a distance-based exercise prescription of walking or running should provide a clinician or researcher with a closer estimation of overall accumulated exercise and resultant weight loss.
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Affiliation(s)
- Cody E Morris
- School of Kinesiology, Recreation & Sport, Western Kentucky University, Bowling Green, KY, USA
| | - John C Garner
- Department of Kinesiology and Health Promotion, Troy University, Troy, AL, USA
| | - Scott G Owens
- Department of Health, Exercise Science and Recreation Management, The University of Mississippi, University, MS, USA
| | - Melinda W Valliant
- Department of Nutrition and Hospitality Management, The University of Mississippi, University, MS, USA
| | - Hunter Debusk
- Department of Industrial & Systems Engineering, Mississippi State University, Mississippi State, MS, USA
| | - Mark Loftin
- Department of Health, Exercise Science and Recreation Management, The University of Mississippi, University, MS, USA
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Morris CE, Chander H, Garner JC, DeBusk H, Owens SG, Valliant MW, Loftin M. Evaluating Perturbations To Human Balance Following An Exercise Intervention In Previously Sedentary, Overweight Adults. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000518727.19563.c5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wiczynski T, Morris CE, Chander H, Wilson SJ, Loftin M, Wade C, Garner JC. Impact of Alternative Footwear on Human Energy Expenditure. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000519518.58552.3d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Dispennette AK, Morris CE, Chander H, Garner JC, DeBusk H, Owens SG, Valliant MW, Loftin M. Impact Of An Exercise Intervention On Human Balance Center Of Pressure Sway Parameters In Previously Sedentary, Overweight Adults. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000518732.42433.98] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Morris CE, Garner JC, Owens SG, Valliant MW, Loftin M. Evaluation of the accuracy of a previously published equation to predict energy expenditure per unit distance following an exercise intervention in previously sedentary overweight adults. Gazz Med Ital - Arch Sci Med 2016. [DOI: 10.23736/s0393-3660.16.03316-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Borschinger B, Bartoli C, Chandeysson C, Guilbaud C, Parisi L, Bourgeay JF, Buisson E, Morris CE. A set of PCRs for rapid identification and characterization of Pseudomonas syringae phylogroups. J Appl Microbiol 2016; 121:903. [PMID: 27528015 DOI: 10.1111/jam.13219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B Borschinger
- INRA, Unité de Pathologie Végétale, Domaine de St Maurice, BP 94, 84140, Montfavet, France.,IMBE, Université d'Avignon et des Pays de Vaucluse, UMR CNRS IRD Aix Marseille Université, Site Agroparc BP 61207, 84911, Avignon, France
| | - C Bartoli
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France.,CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
| | - C Chandeysson
- INRA, Unité de Pathologie Végétale, Domaine de St Maurice, BP 94, 84140, Montfavet, France
| | - C Guilbaud
- INRA, Unité de Pathologie Végétale, Domaine de St Maurice, BP 94, 84140, Montfavet, France
| | - L Parisi
- INRA, Unité de Pathologie Végétale, Domaine de St Maurice, BP 94, 84140, Montfavet, France
| | - J F Bourgeay
- INRA, Unité de Pathologie Végétale, Domaine de St Maurice, BP 94, 84140, Montfavet, France
| | - E Buisson
- IMBE, Université d'Avignon et des Pays de Vaucluse, UMR CNRS IRD Aix Marseille Université, Site Agroparc BP 61207, 84911, Avignon, France
| | - C E Morris
- INRA, Unité de Pathologie Végétale, Domaine de St Maurice, BP 94, 84140, Montfavet, France
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Abstract
Sick excitable cells (ie, Nav channel-expressing cells injured by trauma, ischemia, inflammatory, and other conditions) typically exhibit "acquired sodium channelopathies" which, we argue, reflect bleb-damaged membranes rendering their Nav channels "leaky." The situation is excitotoxic because untreated Nav leak exacerbates bleb damage. Fast Nav inactivation (a voltage-independent process) is so tightly coupled, kinetically speaking, to the inherently voltage-dependent process of fast activation that when bleb damage accelerates and thus left-shifts macroscopic fast activation, fast inactivation accelerates to the same extent. The coupled g(V) and availability(V) processes and their window conductance regions consequently left-shift by the same number of millivolts. These damage-induced hyperpolarizing shifts, whose magnitude increases with damage intensity, are called coupled left shift (CLS). Based on past work and modeling, we discuss how to test for Nav-CLS, emphasizing the virtue of sawtooth ramp clamp. We explain that it is the inherent mechanosensitivity of Nav activation that underlies Nav-CLS. Using modeling of excitability, we show the known process of Nav-CLS is sufficient to predict a wide variety of "sick excitable cell" phenomena, from hyperexcitability through to depolarizing block. When living cells are mimicked by inclusion of pumps, mild Nav-CLS produces a wide array of burst phenomena and subthreshold oscillations. Dynamical analysis of mild damage scenarios shows how these phenomena reflect changes in spike thresholds as the pumps try to counteract the leaky Nav channels. Smart Nav inhibitors designed for sick excitable cells would target bleb-damaged membrane, buying time for cell-mediated removal or repair of Nav-bearing membrane that has become bleb-damaged (ie, detached from the cytoskeleton).
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Affiliation(s)
- C E Morris
- Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - B Joos
- University of Ottawa, Ottawa, ON, Canada
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Morris CE, Garner JC, Owens SG, Valliant MW, Loftin M. Comparing Distance-based Vs. Time-based Exercise Prescriptions Of Walking And Running For Improvement Of Blood Lipid Profile And Blood Glucose. Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000486826.95354.5e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Borschinger B, Bartoli C, Chandeysson C, Guilbaud C, Parisi L, Bourgeay JF, Buisson E, Morris CE. A set of PCRs for rapid identification and characterization of Pseudomonas syringae phylogroups. J Appl Microbiol 2016; 120:714-23. [PMID: 26661140 DOI: 10.1111/jam.13017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/29/2015] [Accepted: 11/26/2015] [Indexed: 12/13/2022]
Abstract
AIMS The aim of this study was to develop a rapid PCR-based method for the specific detection of individual phylogroups of the Pseudomonas syringae complex. METHODS AND RESULTS Seven primer pairs were developed by analysing whole genomes of 54 Ps. syringae strains. The specificity and sensitivity of these primer pairs were assessed on 236 strains from a large and comprehensive Ps. syringae collection. The method was also validated by characterizing the phylogenetic diversity of 174 putative Ps. syringae isolates from kiwifruit and apricot orchards of southeastern France. CONCLUSION Our PCR-based method allows for the detection and characterization of nine of the 13 Ps. syringae phylogroups (phylogroups 1, 2, 3, 4, 7, 8, 9, 10 and 13). SIGNIFICANCE AND IMPACT OF THE STUDY To date, phylogenetic affiliation within the Ps. syringae complex was only possible by sequencing housekeeping genes. Here, we propose a rapid PCR-based method for the detection of specific phylogroups of the Ps. syringae complex. Furthermore, for the first time we reveal the presence of Ps. syringae strains belonging to phylogroups 10 and 13 as epiphytes on plants, whereas they had previously only been observed in aquatic habitats.
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Affiliation(s)
- B Borschinger
- Unité de Pathologie Végétale, INRA, Montfavet, France.,IMBE, Université d'Avignon et des Pays de Vaucluse, UMR CNRS IRD Aix Marseille Université, Avignon, France
| | - C Bartoli
- Laboratoire des Interactions Plantes-Microorganismes (LIPM), INRA, Castanet-Tolosan, France.,Laboratoire des Interactions Plantes-Microorganismes (LIPM), CNRS, Castanet-Tolosan, France
| | - C Chandeysson
- Unité de Pathologie Végétale, INRA, Montfavet, France
| | - C Guilbaud
- Unité de Pathologie Végétale, INRA, Montfavet, France
| | - L Parisi
- Unité de Pathologie Végétale, INRA, Montfavet, France
| | - J F Bourgeay
- Unité de Pathologie Végétale, INRA, Montfavet, France
| | - E Buisson
- IMBE, Université d'Avignon et des Pays de Vaucluse, UMR CNRS IRD Aix Marseille Université, Avignon, France
| | - C E Morris
- Unité de Pathologie Végétale, INRA, Montfavet, France
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Garner J, Chander H, Morris CE, Wilson SJ, Wade C. Impact of Alternative Footwear on Balance Perturbations. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477108.20887.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hill CM, Chander H, Morris CE, Wilson SJ, Knight AC, Holmes ME, DeBusk H, Wade C, Garner JC. Impact Of Low Intensity Workload On Muscle Exertion In Alternative Footwear. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477109.28510.62] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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DeBusk H, Chander H, Morris CE, Wilson SJ, Knight AC, Holmes ME, Hill CM, Wade C, Garner JC. The Effect Of Commonly Used Alternative Footwear On Balance. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477226.73777.4f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wilson SJ, Chander H, Morris CE, Garner JC, Wade C. Alternative Footwear’s Influence on Static Balance Following a One Mile Walk. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477221.43283.df] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Morris CE, Garner JC, Owens SG, Valliant MW, Haskins MA, Loftin M. Comparing Distance-based Vs. Time-based Exercise Prescriptions Of Walking And Running For Improvement Of Body Composition. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477527.43154.90] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lagriffoul A, Boudenne JL, Absi R, Ballet JJ, Berjeaud JM, Chevalier S, Creppy EE, Gilli E, Gadonna JP, Gadonna-Widehem P, Morris CE, Zini S. Bacterial-based additives for the production of artificial snow: what are the risks to human health? Sci Total Environ 2010; 408:1659-1666. [PMID: 20097407 DOI: 10.1016/j.scitotenv.2010.01.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 12/29/2009] [Accepted: 01/06/2010] [Indexed: 05/28/2023]
Abstract
For around two decades, artificial snow has been used by numerous winter sports resorts to ensure good snow cover at low altitude areas or more generally, to lengthen the skiing season. Biological additives derived from certain bacteria are regularly used to make artificial snow. However, the use of these additives has raised doubts concerning the potential impact on human health and the environment. In this context, the French health authorities have requested the French Agency for Environmental and Occupational Health Safety (Afsset) to assess the health risks resulting from the use of such additives. The health risk assessment was based on a review of the scientific literature, supplemented by professional consultations and expertise. Biological or chemical hazards from additives derived from the ice nucleation active bacterium Pseudomonas syringae were characterised. Potential health hazards to humans were considered in terms of infectious, toxic and allergenic capacities with respect to human populations liable to be exposed and the means of possible exposure. Taking into account these data, a qualitative risk assessment was carried out, according to four exposure scenarios, involving the different populations exposed, and the conditions and routes of exposure. It was concluded that certain health risks can exist for specific categories of professional workers (mainly snowmakers during additive mixing and dilution tank cleaning steps, with risks estimated to be negligible to low if workers comply with safety precautions). P. syringae does not present any pathogenic capacity to humans and that the level of its endotoxins found in artificial snow do not represent a danger beyond that of exposure to P. syringae endotoxins naturally present in snow. However, the risk of possible allergy in some particularly sensitive individuals cannot be excluded. Another important conclusion of this study concerns use of poor microbiological water quality to make artificial snow.
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Affiliation(s)
- A Lagriffoul
- Agence Française de Sécurité Sanitaire de l'Environnement et du Travail, avenue du Général Leclerc, Maisons-Alfort, France
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Young JM, Allen C, Coutinho T, Denny T, Elphinstone J, Fegan M, Gillings M, Gottwald TR, Graham JH, Iacobellis NS, Janse JD, Jacques MA, Lopez MM, Morris CE, Parkinson N, Prior P, Pruvost O, Neto JR, Scortichini M, Takikawa Y, Upper CD. Plant-pathogenic bacteria as biological weapons - real threats? Phytopathology 2008; 98:1060-1065. [PMID: 18943451 DOI: 10.1094/phyto-98-10-1060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
At present, much attention is being given to the potential of plant pathogens, including plant-pathogenic bacteria, as biological weapons/bioterror weapons. These two terms are sometimes used interchangeably and there is need for care in their application. It has been claimed that clandestine introduction of certain plant-pathogenic bacteria could cause such crop losses as to impact so significantly on a national economy and thus constitute a threat to national security. As a separate outcome, it is suggested that they could cause serious public alarm, perhaps constituting a source of terror. Legislation is now in place to regulate selected plant-pathogenic bacteria as potential weapons. However, we consider it highly doubtful that any plant-pathogenic bacterium has the requisite capabilities to justify such a classification. Even if they were so capable, the differentiation of pathogens into a special category with regulations that are even more restrictive than those currently applied in quarantine legislation of most jurisdictions offers no obvious benefit. Moreover, we believe that such regulations are disadvantageous insofar as they limit research on precisely those pathogens most in need of study. Whereas some human and animal pathogens may have potential as biological or bioterror weapons, we conclude that it is unlikely that any plant-pathogenic bacterium realistically falls into this category.
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Dreux N, Albagnac C, Sleator RD, Hill C, Carlin F, Morris CE, Nguyen-the C. Glycine betaine improves Listeria monocytogenes tolerance to desiccation on parsley leaves independent of the osmolyte transporters BetL, Gbu and OpuC. J Appl Microbiol 2007; 104:1221-7. [PMID: 17976173 DOI: 10.1111/j.1365-2672.2007.03623.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
AIMS To investigate the effect of glycine betaine (GB) on the survival of Listeria monocytogenes on leaf surfaces under low relative humidity (RH). METHODS AND RESULTS The addition of GB (> or = 25 mmol l(-1)) improved the survival of L. monocytogenes under low RH on parsley leaves, thus suggesting that GB can improve the tolerance of L. monocytogenes to desiccation. Ten times less GB was needed to improve L. monocytogenes survival under low RH on nonbiological surfaces compared with parsley leaves, suggesting that, on the leaf surface, L. monocytogenes may have to compete for the available GB with autochthonous bacteria and/or the plant itself. Wild type and mutants carrying deletions in the three GB uptake systems, BetL, Gbu and OpuC, behaved similarly with and without added GB on parsley leaves (P > 0.05). In addition, preaccumulation of GB, triggered by osmotic stress prior to inoculation, failed to improve survival under low RH compared with osmotic stress without GB accumulation. CONCLUSIONS Exogenous GB had a protective effect on L. monocytogenes cells from desiccation during survival on parsley leaves. This effect was independent of intracellular GB accumulation by the known uptake systems. SIGNIFICANCE AND IMPACT OF THE STUDY Presence of GB could improve the survival of L. monocytogenes to desiccation on leaf surfaces and nonbiological surfaces.
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Affiliation(s)
- N Dreux
- INRA, UMR 408, Sécurité et Qualité des Produits d'Origine Végétale, Avignon, F-84914, France, Univ Avignon, Avignon, F-84029, France.
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Dreux N, Albagnac C, Federighi M, Carlin F, Morris CE, Nguyen-the C. Viable but non-culturableListeria monocytogeneson parsley leaves and absence of recovery to a culturable state. J Appl Microbiol 2007; 103:1272-81. [PMID: 17897231 DOI: 10.1111/j.1365-2672.2007.03351.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To investigate the presence of viable but non-culturable Listeria monocytogenes during survival on parsley leaves under low relative humidity (RH) and to evaluate the ability of L. monocytogenes to recover from VBNC to culturable state under satured humidity. METHODS AND RESULTS Under low RH (47-69%) on parsley leaves, the initial number of L. monocytogenes populations counted on non selective media (10(9) L. monocytogenes per leaf on TSA) was reduced by 6 log10 scales in 15 days, whereas number of viable L. monocytogenes counted under the microscope was reduced by 3-4 log10 scales, indicating the presence of VBNC cells. This was demonstrated on three L. monocytogenes strains (EGDe, Bug 1995 and LmP60). Changing from low to 100% RH permitted an increase of the culturable counts of L. monocytogenes and this growth was observed only when residual culturable cells were present. Moreover, VBNC L. monocytogenes inoculated on parsley leaves did not become culturable after incubation under 100% RH. CONCLUSIONS Dry conditions induced VBNC L. monocytogenes on parsley leaves but these VBNC were likely unable to recover culturability after transfer to satured humidity. SIGNIFICANCE AND IMPACT OF STUDY Enumeration on culture media presumably under-estimates the number of viable L. monocytogenes on fresh produce after exposure to low RH.
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Affiliation(s)
- N Dreux
- INRA, UMR408, Sécurité et Qualité des Produits d'Origine Végétale, Avignon, F-84914, France.
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Boureau T, Jacques MA, Berruyer R, Dessaux Y, Dominguez H, Morris CE. Comparison of the phenotypes and genotypes of biofilm and solitary epiphytic bacterial populations on broad-leaved endive. Microb Ecol 2004; 47:87-95. [PMID: 15259273 DOI: 10.1007/s00248-002-0106-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The discovery that biofilms are ubiquitous among the epiphytic microflora of leaves has prompted research about the impact of biofilms on the ecology of epiphytic microorganisms and on the efficiency of strategies to manage these populations for disease control and to ensure food safety. Biofilms are likely to influence the microenvironment and phenotype of the microorganisms they harbor. However, it is also important to determine whether there are differences in the types of bacteria within biofilms compared to those outside of biofilms so as to better target microorganisms via disease control strategies. Broad-leaved endive (Cichorium endivia var. latifolia) harbors biofilms containing fluorescent pseudomonads. These bacteria can cause considerable post-harvest losses when this plant is used for manufacturing minimally processed salads. To determine whether the population structure of the fluorescent pseudomonads in biofilms is different from that outside of biofilms on the same leaves, bacteria were isolated quantitatively from the biofilm and solitary components of the epiphytic population on leaves of field-grown broad-leaved endive. Population structure was determined in terms of taxonomic identities of the bacteria isolated, in terms of genotypic profiles, and in terms of phenotypic traits related to surface colonization and biofilm formation. The results illustrate that there are no systematic differences in the composition and structure of biofilm and solitary populations of fluorescent pseudomonads, in terms of either genotypic profiles or phenotypic profiles of the strains. However, Gram-positive bacteria tended to occur more frequently within biofilms than outside of biofilms. We suggest that leaf colonization by fluorescent pseudomonads involves a flux of cells between biofilm and solitary states. This would allow bacteria to exploit the advantages of these two types of existence; biofilms would favor resistance to stressful conditions, whereas solitary cells could foster spread of bacteria to newly colonizable sites on leaves as environmental conditions fluctuate.
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Affiliation(s)
- T Boureau
- Division of General Microbiology, University of Helsinki, Biocenter, P.O. Box 56, Helsinki, Finland
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Abstract
Over most of their surface, neurons are surrounded by a narrow extracellular gap across which they make adhesive cell-cell contacts. Thus constrained, how do they regulate their geometry when osmotically perturbed? Specifically, are there any interesting consequences of local osmosis in such conditions? Using confocal imaging of shrinking neurons in culture, we observe water exiting into the cell-substratum gap. This water efflux generates a hydrostatic pressure that, at discrete (low adhesion) sites, causes the neuron's excess plasma membrane to invaginate, thus compensating for shrinkage with a pseudo-intracellular volume. To identify the minimal requirements of the process, a compartment/flux model was constructed. It comprises, essentially, a large liposome adhering in a labyrinthine fashion to a substratum. The model predicts that invaginations form at the cell-substratum interface under the influence of local osmosis, provided that adhesion across the gap is neither too tight nor too loose. Local osmosis in the central nervous system, in contrast to epithelia, is usually considered a mishap, not a physiological opportunity. We postulate, however, that local osmotic forces acting in conjunction with confined extracellular spaces could be harnessed in service of surface area, shape, and volume regulation when intense neural activity alters a neuron's osmotic balance.
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Affiliation(s)
- C E Morris
- Neuroscience, Ottawa Health Research Institute, Ottawa Hospital, Ottawa, Ontario, Canada.
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Morris CE. Mechanoprotection of the plasma membrane in neurons and other non-erythroid cells by the spectrin-based membrane skeleton. Cell Mol Biol Lett 2002; 6:703-20. [PMID: 11598643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
Though the cytomechanics of spectrin have been explored only for erythrocytes, it is thought that the spectrin skeleton acts universally to support the otherwise mechanically vulnerable cell surface bilayer. Evidence for this role is beginning to accumulate and is reviewed here. Compared to that for erythrocytes, cells whose simplicity facilitates biophysical approaches, the evidence is indirect. One way that membrane skeleton/bilayer interactions have been probed is via the behavior of mechanosusceptible ion channels - channel whose gating is perturbed by abnormally high bilayer tension. These initially unresponsive channels become progressively more mechanoresponsive as stretch and chemical reagents damage the membrane skeleton. The straightforward implication is that the intact membrane skeleton is mechanoprotective. In non-erythroid cells there is continual trafficking of bilayer to and from the plasma membrane. Some of the traffic involves spectrin-lined vacuolar membrane. Several lines of evidence suggest that when neurons elongate and remodel their neurites, membrane skeleton-based mechanoprotection allows the dynamic vacuoles and the plasma membrane to participate in mechanosensitive surface area expansion and retrieval.
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Affiliation(s)
- C E Morris
- Neurosciences, Ottawa Health Research Institute, Ottawa Hospital, 725 Parkdale Ave, Ottawa, Ontario, Canada K1Y 4K9
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Abstract
Mechanosensitive (MS) ion channels are ubiquitous in eukaryotic cell types but baffling because of their contentious physiologies and diverse molecular identities. In some cellular contexts mechanically responsive ion channels are undoubtedly mechanosensory transducers, but it does not follow that all MS channels are mechanotransducers. Here we demonstrate, for an archetypical voltage-gated channel (Shaker-IR; inactivation-removed), robust MS channel behavior. In oocyte patches subjected to stretch, Shaker-IR exhibits both stretch-activation (SA) and stretch-inactivation (SI). SA is seen when prestretch P(open) (set by voltage) is low, and SI is seen when it is high. The stretch effects occur in cell-attached and excised patches at both macroscopic and single-channel levels. Were one ignorant of this particular MS channel's identity, one might propose it had been designed as a sophisticated reporter of bilayer tension. Knowing Shaker-IR's provenance and biology, however, such a suggestion would be absurd. We argue that the MS responses of Shaker-IR reflect not overlooked "mechano-gating" specializations of Shaker, but a common property of multiconformation membrane proteins: inherent susceptibility to bilayer tension. The molecular diversity of MS channels indicates that susceptibility to bilayer tension is hard to design out of dynamic membrane proteins. Presumably the cost of being insusceptible to bilayer tension often outweighs the benefits, especially where the in situ milieu of channels can provide mechanoprotection.
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Affiliation(s)
- C X Gu
- Department of Medicine, University of Ottawa, Neurosciences, Ottawa Health Research Institute, The Ottawa Hospital, Ottawa, Ontario K1Y 4K9, Canada
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Juranka PF, Haghighi AP, Gaertner T, Cooper E, Morris CE. Molecular cloning and functional expression of Xenopus laevis oocyte ATP-activated P2X4 channels. Biochim Biophys Acta 2001; 1512:111-24. [PMID: 11334629 DOI: 10.1016/s0005-2736(01)00313-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
All cells contain mechanosensitive ion channels, yet the molecular identities of most are unknown. The purpose of our study was to determine what encodes the Xenopus oocyte's mechanosensitive cation channel. Based on the idea that homologues to known channels might contribute to the stretch channels, we screened a Xenopus oocyte cDNA library with cation channel probes. Whereas other screens were negative, P2X probes identified six isoforms of the P2X4 subtype of ATP-gated channels. From RNase protection assays and RT-PCR, we demonstrated that Xenopus oocytes express P2X4 mRNA. In expression studies, four isoforms produced functional ATP-gated ion channels; however, one, xP2X4c, had a conserved cysteine replaced by a tyrosine and failed to give rise to functional channels. By changing the tyrosine to a cysteine, we showed that this cysteine was crucial for function. We raised antibodies against a Xenopus P2X4 C-terminal peptide to investigate xP2X4 protein expression. This affinity purified anti-xP2X4 antibody recognized a 56 kDa glycosylated Xenopus P2X4 protein expressed in stably transfected HEK-293 cells and in P2X4 cDNA injected oocytes overexpressing the cloned P2X4 channels; however, it failed to recognize proteins in control, uninjected oocytes. This suggests that P2X4 channels and mechanosensitive cation channels are not linked. Instead, oocyte P2X4 mRNA may be part of the stored pool of stable maternal mRNA that remains untranslated until later developmental stages.
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Affiliation(s)
- P F Juranka
- Ottawa Health Research Institute, ON, Canada
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Toussaint V, Morris CE, Carisse O. A New Semi-Selective Medium for Xanthomonas campestris pv. vitians, the Causal Agent of Bacterial Leaf Spot of Lettuce. Plant Dis 2001; 85:131-136. [PMID: 30831931 DOI: 10.1094/pdis.2001.85.2.131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A semi-selective medium containing maltose, methyl green, and antibiotics (MMG) was developed for the isolation of Xanthomonas campestris pv. vitians. The semi-selective medium was evaluated based on plating efficiency of X. campestris pv. vitians in cell suspensions of pure cultures from leaves and soil. MMG medium allowed recovery of 5.7 to 30.6% of the X. campestris pv. vitians colonies recovered on nutrient agar and 0.1 to 8.4% of those recovered on 1/10-strength tryptic soy agar. MMG inhibited growth of most background bacteria and allowed reliable identification of X. campestris pv. vitians. The semi-selective medium contained (per liter) maltose (10 g), tryptone (5 g), K2HPO4 (3.5 g), KH2PO4 (2.75 g), trace elements (0.02 to 1.0 mg), methyl green (2 ml of a 1% aqueous solution), amoxicillin (32 mg), cephalothin (32 mg), cycloheximide (50 mg), and agar (15 g).
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Affiliation(s)
- V Toussaint
- MacDonald Campus of McGill University, 21 111 Lakeshore, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada
| | - C E Morris
- Station de Pathologie Végétale, INRA d' Avignon, 84143, Monfavet, Cedex, France
| | - O Carisse
- Horticultural Research and Development Centre, Agriculture and Agri-Food Canada, 430 Gouin Boulevard, St-Jean-sur-Richelieu, Quebec
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Abstract
The beautifully orchestrated regulation of cell shape and volume are central themes in cell biology and physiology. Though it is less well recognized, cell surface area regulation also constitutes a distinct task for cells. Maintaining an appropriate surface area is no automatic side effect of volume regulation or shape change. The issue of surface area regulation (SAR) would be moot if all cells resembled mammalian erythrocytes in being constrained to change shape and volume using existing surface membrane. But these enucleate cells are anomalies, possessing no endomembrane. Most cells use endomembrane to continually rework their plasma membrane, even while maintaining a given size or shape. This membrane traffic is intensively studied, generally with the emphasis on targeting and turnover of proteins and delivery of vesicle contents. But surface area (SA) homeostasis, including the controlled increase or decrease of SA, is another of the outcomes of trafficking. Our principal aims, then, are to highlight SAR as a discrete cellular task and to survey evidence for the idea that membrane tension is central to the task. Cells cannot directly "measure" their volume or SA, yet must regulate both. We posit that a homeostatic relationship exists between plasma membrane tension and plasma membrane area, which implies that cells detect and respond to deviations around a membrane tension set point. Maintenance of membrane strength during membrane turnover, a seldom-addressed aspect of SA dynamics, we examine in the context of SAR. SAR occurs in both animal and plant cells. The review shows the latter to be a continuing source of groundbreaking work on tension-sensitive SAR, but is principally slanted to animal cells.
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Affiliation(s)
- C E Morris
- Department of Medicine, University of Ottawa, Neuroscience, Loeb Health Research Institute, Ottawa Hospital, Ontario, Canada
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Morris CE, Glaux C, Latour X, Gardan L, Samson R, Pitrat M. The Relationship of Host Range, Physiology, and Genotype to Virulence on Cantaloupe in Pseudomonas syringae from Cantaloupe Blight Epidemics in France. Phytopathology 2000; 90:636-646. [PMID: 18944544 DOI: 10.1094/phyto.2000.90.6.636] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT In 1993, a bacterial blight caused important losses of cantaloupe (Cucumis melo var. cantalupensis) in southwestern France and has now been reported in all cantaloupe-growing regions of France. The causal agent of this blight is Pseudomonas syringae, although on a worldwide basis this bacterium has not been a major pathogen of melon for over 50 years. To identify the pathovar of the cantaloupe pathogen, we employed biochemical tests, plasmid and chromosomal profiling, and host range studies for 23 strains from cantaloupe and 47 reference strains of 14 pathovars of P. syringae. Numerical analysis of 119 traits, serological typing, syringomycin production, and BOX-polymerase chain reaction profiles did not allow us to differentiate among pathovars related to P. syringae pv. syringae. Host range studies of cantaloupe and references strains on 18 plant species showed that virulence to sugar beet was a common feature of strains virulent on cantaloupe, but was not common to strains avirulent on cantaloupe. Virulence to other species of plants varied among strains, but the overall extent of the host range was proportional to aggressiveness to cantaloupe. We propose that the strains attacking cantaloupe in France be considered P. syringae pv. aptata and that adequate host range testing may reveal that this pathovar is the cause of cantaloupe blight reported in other parts of the world.
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Mortley DG, Bonsi CK, Loretan PA, Hill WA, Morris CE. High relative humidity increases yield, harvest index, flowering, and gynophore growth of hydroponically grown peanut plants. HortScience 2000; 35:46-48. [PMID: 11725789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Growth chamber experiments were conducted to study the physiological and growth response of peanut (Arachis hypogaea L.) to 50% and 85% relative humidity (RH). The objective was to determine the effects of RH on pod and seed yield, harvest index, and flowering of peanut grown by the nutrient film technique (NFT). 'Georgia Red' peanut plants (14 days old) were planted into growth channels (0.15 x 0.15 x 1.2 m). Plants were spaced 25 cm apart with 15 cm between channels. A modified half-Hoagland solution with an additional 2 mM Ca was used. Solution pH was maintained between 6.4 and 6.7, and electrical conductivity (EC) ranged between 1100 and 1200 microS cm-1. Temperature regimes of 28/22 degrees C were maintained during the light/dark periods (12 hours each) with photosynthetic photon flux (PPF) at canopy level of 500 micromoles-m-2s-1. Foliage and pod fresh and dry weights, total seed yield, harvest index (HI), and seed maturity were greater at high than at low RH. Plants grown at 85% RH had greater total and individual leaflet area and stomatal conductance, flowered 3 days earlier and had a greater number of flowers reaching anthesis. Gynophores grew more rapidly at 85% than at 50% RH.
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Affiliation(s)
- D G Mortley
- Center for Food and Environmental Systems for Human Exploration of Space, Department of Agricultural Sciences, Tuskegee University, Tuskegee, AL 36088, USA
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Abstract
As a cell's shape and volume change. its surface area must re-adjust. How is the plasma membrane's spectrin skeleton implicated? For erythrocytes, cells of fixed surface area, spectrin responses to mechanical disturbances have been studied, but for more typical cells with changeable surface areas, they have not. In rapidly shrinking cells, surface membrane at an adherent substratum invaginates, forming transient vacuole-like dilations (VLDs). We exploited this readily inducible surface area perturbation to pose a simple question: is newly invaginated plasma membrane naked or is it supported by a spectrin skeleton? The spectrin skeleton was examined immunocytochemically in L6 cells (rat skeletal muscle) before and after VLD formation, using fixation in cold methanol and 4112, an antibody against beta-fodrin and beta-spectrin. 4112 was visualized by confocal fluorescence microscopy, while paired phase contrast images independently located the VLDs. To generate VLDs, cells were hypotonically swelled then reshrunk in isotonic medium. Swollen L6 cells maintained their plasma membrane (sarcolemma) spectrin skeleton. Within minutes of subsequent shrinkage, VLDs of 1-2 microm diameter invaginated at the substratum surface of myotubes. Both sarcolemma and VLDs were lined by a relatively uniform spectrin skeleton. Z-series suggested that some of the spectrin skeleton-lined sarcolemma became internalized as vacuoles.
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Affiliation(s)
- T L Herring
- Loeb Health Research Institute, Ottawa Hospital, Ontario, Canada
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Herring TL, Cohan CS, Welnhofer EA, Mills LR, Morris CE. F-actin at newly invaginated membrane in neurons: implications for surface area regulation. J Membr Biol 1999; 171:151-69. [PMID: 10489427 DOI: 10.1007/s002329900567] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Neuronal shape and volume changes require accompanying cell surface adjustments. In response to osmotic perturbations, neurons show evidence of surface area regulation; shrinking neurons invaginate membrane at the substratum, pinch off vacuoles, and lower their membrane capacitance. F-actin is implicated in reprocessing newly invaginated membrane because cytochalasin causes the transient shrinking-induced invaginations, vacuole-like dilations (VLDs), to persist indefinitely instead of undergoing recovery. To help determine if cortical F-actin indeed contributes to cell surface area regulation, we test, here, the following hypothesis: invaginating VLD membrane rapidly establishes an association with F-actin and this association contributes to VLD recovery. Cultured molluscan (Lymnaea) neurons, whose large size facilitates three-dimensional imaging, were used. In fixed neurons, fluorescent F-actin stains were imaged. In live neurons, VLD membrane was monitored by brightfield microscopies and actin was monitored via a fluorescent tag. VLD formation (unlike VLD recovery) is cytochalasin insensitive and consistent with this, VLDs formed readily in cytochalasin-treated neurons but showed no association with F-actin. Normally, however (i.e., no cytochalasin), VLDs were foci for rapid reorganization of F-actin. At earliest detection (1-2 min), nascent VLDs were entirely coated with F-actin and by 5 min, VLD mouths (i.e. , at the substratum) had become annuli of F-actin-rich motile leading edge. Time lapse images from live neurons showed these rings to be motile filopodia and lamellipodia. The retrieval of VLD membrane (vacuolization) occurred via actin-associated constriction of VLD mouths. The interplay of surface membrane and cortical cytoskeleton in osmotically perturbed neurons suggests that cell surface area and volume adjustments are coordinated in part via mechanosensitive F-actin dynamics.
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Affiliation(s)
- T L Herring
- Departments of Biology and Medicine, University of Ottawa, Ottawa, Ontario, Canada, K1Y4E9
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Morris CE, Popper SE. Gender and effect of impact acceleration on neck motion. Aviat Space Environ Med 1999; 70:851-6. [PMID: 10503748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
BACKGROUND With the opening of the fighter cockpit to women, it became imperative to expand the current database of responses of females to both sustained and impact acceleration environments. With less upper-body strength (lean body mass) than men, it was hypothesized that women would not brace their heads as effectively against the loads occurring during high G-loading in flight and during impact and escape. This scenario creates increased potential for injury, exacerbated by the changing center of gravity and weight of helmets due to technological advances (e.g., night vision, head-up displays, etc.). METHODS The main objective of this experimental effort was measuring the ability of subjects of both sexes to brace against an impact acceleration of -6.5 Gx or +4.0 Gy. An attempt was made to identify a correlation between such ability, static strength measurements, anthropometric measurements, or any combination thereof. RESULTS No correlation was found between any of the static strength or anthropomorphic parameters and the amplitude of head motion. The isometric strength measurements correlated well with the size, weight, and neck circumference of the subjects, but none of these proved useful in predicting head displacement. However, there was a strong relationship between neck force exerted just before impact and head motion in the -Gx study, and somewhat less correlation for the +Gy impacts. CONCLUSION It is useful to estimate resistance to impact by measuring neck strength, but only under conditions where the subject is highly motivated.
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Affiliation(s)
- C E Morris
- Escape and Impact Protection Branch, Crew Systems Directorate, Armstrong Laboratory, Wright-Patterson AFB, OH, USA
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Morris CE, Gu CX, Juranka PF, Tabarean N. The mechanosusceptibility of voltage-gated ion channels. Comp Biochem Physiol A Mol Integr Physiol 1999. [DOI: 10.1016/s1095-6433(99)90069-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
The alpha subunit of the human skeletal muscle Na(+) channel recorded from cell-attached patches yielded, as expected for Xenopus oocytes, two current components that were stable for tens of minutes during 0.2 Hz stimulation. Within seconds of applying sustained stretch, however, the slower component began decreasing and, depending on stretch intensity, disappeared in 1-3 min. Simultaneously, the faster current increased. The resulting fast current kinetics and voltage sensitivity were indistinguishable from the fast components 1) left after 10 Hz depolarizations, and 2) that dominated when alpha subunit was co-expressed with human beta1 subunit. Although high frequency depolarization-induced loss of slow current was reversible, the stretch-induced slow-to-fast conversion was irreversible. The conclusion that stretch converted a single population of alpha subunits from an abnormal slow to a bona fide fast gating mode was confirmed by using gigaohm seals formed without suction, in which fast gating was originally absent. For brain Na(+) channels, co-expressing G proteins with the channel alpha subunit yields slow gating. Because both stretch and beta1 subunits induced the fast gating mode, perhaps they do so by minimizing alpha subunit interactions with G proteins or with other regulatory molecules available in oocyte membrane. Because of the possible involvement of oocyte molecules, it remains to be determined whether the Na(+) channel alpha subunit was directly or secondarily susceptible to bilayer tension.
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Affiliation(s)
- I V Tabarean
- Departments of Medicine and Biology, University of Ottawa, and Department of Neurosciences, Loeb Health Research Institute, Ottawa Hospital, Ottawa, Ontario K1Y 4E9, Canada
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