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Sympatric Soil Microbe Interactions between Streptomyces and Fusarium Isolates
Get PDFInterkingdom interactions between soil bacteria and fungi may play a critical role in occurrence of disease suppressive soils, yet our understanding of these interactions remains limited. Streptomyces are well-known producers of antimicrobial compounds important to medicine and agriculture. Production of these secondary metabolites is often mediated by quorum sensing. Most Streptomyces research occurs in single species experiments, yet new metabolites have been discovered in interspecies co-culture experiments. Interspecies, intergenic, and interkingdom co-culture research will likely reveal many valuable compounds, and strengthen our understanding of complex ecological interactions in soil microbiomes. Interactions between sympatric Streptomyces and Fusarium isolates from disease suppressive soils were investigated in this study. Dual layer agar inhibition assay revealed inhibition of Streptomyces by Fusarium in all pairwise combinations, while only 46% of pairwise combinations showed Fusarium inhibition by Streptomyces. Streptomyces isolate S2-2 was shown to produce antifungal compounds in a population density dependent manner, likely governed by quorum sensing. Exposure of S2-2 broth culture to conditioned media which likely contained autoinducers from mature S2-2 culture was shown to cause a significant increase in antifungal production earlier than control groups. Simultaneous inoculation of S2-2 and Fusarium isolate F10-8 was shown to cause a significant decrease in antifungal production. Exploring these interactions is of great importance for antimicrobial drug discovery, identifying useful microbial biological control agents, and improving our ability to promote disease suppression in soils
ISBS 2023 CONFERENCE PROCEEDINGS TITLE AND FOREWARD
Get PDFThe ISBS is an international society totally dedicated to biomechanics in sports, whose primary purposes are: To provide a forum for the exchange of ideas for sports biomechanics researchers, coaches and teachers. To bridge the gap between researchers and practitioners. To gather and disseminate information and materials on biomechanics in sports.
Papers underwent a double blinded review process. Each paper in these proceedings has been reviewed by at least two members of the scientific committee
RELIABILITY OF LOW-COST PORTABLE FORCE PLATFORMS FOR MEASURING VERTICAL STIFFNESS DURING RUNNING
Get PDFGround reaction force (GRF) can provide useful information such as vertical stiffness (Kvert) to practitioners working with runners and sprinters, but high equipment costs are hindering applied research. Low-cost portable force platforms may be a useful alternative to traditional biomechanical equipment. Moderately trained runners (n = 9) completed overground running trials at various speeds (2.15-5.78 m/s), Kvert was determined, and a linear regression was used to characterize the relationship between Kvert and running speed. The results showed moderate to high correlation (r2 = 0.54 to 0.87). At 3.9 m/s (14 km/h), the widest regression model confidence interval was 4.4%, which shows this procedure likely provides adequate reliability. Future research should continue to investigate the use of low-cost portable force platforms for measuring running GRF
VARIABILITY IN OVERARM THROWING WITH RESISTANCE IN EXPERIENCED HANDBALL PLAYERS
Get PDFThe purpose of this study was to investigate variability in overarm throwing kinematics with different wearable resistance conditions in handball players as increased variability was expected when testing throwing under new conditions (wearable resistance). Thirteen female handball players performed ten standing throws each under three conditions: normal throws, with light wearable resistance (LW) and heavy wearable resistance (HW), while 3D kinematic data of joint angles and angular velocities were measured with a camera-based motion capture system. The main findings in this study were that variability for all parameters, except a significant lower maximal angular velocity in the high weight condition, compared to the no weight condition, did not differ between the three conditions. It was concluded that wearable resistance had no effect upon variability
USAGE AND ACCEPTABIITY OF DATA NORMALIZATION IN BASEBALL PITCHING
Get PDFTo account for athletes of different sizes, kinetic values are commonly ‘normalized’ by dividing by mass and/or height. However, the creation of a ratio variable requires certain statistical assumptions to be met. The purpose of this study was to determine if elbow valgus torque predicted by pitching velocity is influenced by the normalization method using regression model comparison with normalized torque values. Both mass and mass*height normalization satisfied the correlation and zero intercept assumptions. Results did not agree between analysis methods that elbow valgus torque could be predicted with pitching velocity at the α = 0.05 level, indicating caution should be exercised before normalizing pitching kinetics data without confirming the assumptions for a ratio variable are met
APPLICATION OF SURFACE EMG DECOMPOSITION TO IDENTIFY CHANGES IN NEUROMUSCULAR CONTROL DURING FATIGUING EXERCISE
Get PDFThe purpose of this study was to apply surface EMG decomposition to identify changes in neuromuscular control of lower limb muscles during fatiguing exercise. Trained participants (n=15) completed a repeat sprints cycling fatigue protocol. Motor unit firing rates and motor unit recruitment timings were identified for six muscles. A moderate to strong correlation between firing rates and recruitment timings were identified for individual participant data (r = -0.46 to r = -1.00). No significant group effects were reported when each muscle was examined independently (repeat measures ANOVA; slope, intercept; F \u3c 1.84, p \u3e 0.119). However, changes in regression parameters were indentified for individual participant data. Surface EMG decomposition provides a novel approach for identifying individual changes in neuromuscular control of lower limb muscles during fatiguing exercise
ACUTE EFFECT OF TEXTURED INSOLES ON BIOMECHANICS OF MAXIMAL CYCLING
Get PDFThe aim of the study was to investigate whether a within-session intervention of textured insoles worn in participants cycling shoes altered maximal cycling power output and biomechanics. Ten track sprint cyclists performed sprints on an isokinetic ergometer with and without textured insoles. Key biomechanical variables (crank kinetics, joint kinematics and kinetics) characterising sprint cycling were measured. There was a significant reduction in average crank power for the sprints performed with the textured insoles (P = 0.029) potentially associated with the reported discomfort when using the textured insoles. There were no changes in any other biomechanical measures suggesting a textured insoles intervention may have little impact on maximal cycling performance
ANALYSIS OF RACE WALKING TECHNIQUE POST-COMPETITIVE PERIOD IN A WORLD ATHLETICS CHAMPIONSHIP.
Get PDFThe purpose of this study was to analyse the kinematic variables of an elite race walker gait technique during the post-competitive period in a World Athletics Championship. The elite athlete performed three race walking gait technique tests in a laboratory using three competitive race walking paces. Data for the flight time, step length, step frequency, and speed for the tests was collected. The one-way ANOVA of the three tests did not show statistically significant differences in flight time, step length, step frequency, and speed. However, the findings of this study showed that the competitive race walking pace would influence race walking kinematic variables and the elite athlete’s gait technique