The emergence of bacterial pathogens resistant to all known antibiotics is a global health crisis. Adding to this problem is that major pharmaceutical companies have shifted away from antibiotic discovery due to low profitability. As a result, the pipeline of new antibiotics is essentially dry and many bacteria now resist the effects of most commonly used drugs. To address this global health concern, citizen science through the Small World Initiative (SWI) was formed in 2012. As part of SWI, students isolate bacteria from their local environments, characterize the strains, and assay for antibiotic production. During the 2015 fall semester at Bowling Green State University, students isolated 77 soil‐derived bacteria and genetically characterized strains using the 16S rRNA gene, identified strains exhibiting antagonistic activity, and performed an expanded SWI workflow using transposon mutagenesis to identify a biosynthetic gene cluster involved in toxigenic compound production. We identified one mutant with loss of antagonistic activity and through subsequent whole‐genome sequencing and linker‐mediated PCR identified a 24.9 kb biosynthetic gene locus likely involved in inhibitory activity in that mutant. Further assessment against human pathogens demonstrated the inhibition of Bacillus cereus, Listeria monocytogenes, and methicillin‐resistant Staphylococcus aureus in the presence of this compound, thus supporting our molecular strategy as an effective research pipeline for SWI antibiotic discovery and genetic characterization.
Nonnative fishes have the ability to adapt to environmental conditions in the invaded ecosystem and utilize resources that may have been absent in their native ecosystem. Belonesox belizanus and Cichlasoma urophthalmus are both nonnative fishes in Florida. Ecomorphological studies conclude that C. urophthalmus is a trophic generalist while B. belizanus is a trophic specialist. The current Florida distribution of these species indicates that C. urophthalmus spreads northerly into the colder regions of Florida at a faster rate than B. belizanus. Is it conceivable that this variation in rate of spread is due to differences in temperature response between these ecomorphologically distinct nonnative fishes? This study was designed to test the hypothesis that the prey-capture kinematics and behavior differ between C. urophthalmus and B. belizanus at a given temperature and across temperatures. Two-Way Repeated Measures Multivariate Analysis of Covariance (MANCOVAR) revealed that (1) at a given temperature, excursion and timing variables differed between species and (2) the kinematics of prey-capture did not vary across temperatures in both species.This interspecific comparison suggests that both species have the same temperature tolerance and that any difference in their rate of spread across Florida may be driven by factors other than species-specific physiological tolerance to temperature.
As a consequence of global warming, tropical invasive species are expected to expand their range pole-ward, extending their negative impacts to previously undisturbed, high-latitude ecosystems. Investigating the physiological responses of invasive species to environmental temperature is important because the coupled effects of climate change and species invasion on ecosystems could be more alarming than the effects of each phenomenon independently. Especially in poikilotherms, the rate of motion in muscle-driven biomechanical systems is expected to double for every 10 °C increase in temperature. In this study, we address the question, “How does temperature affect the speed of jaw-movement during prey-capture in invasive fishes?” Kinematic analysis of invasive-fish prey-capture behavior revealed that (1) movement velocities of key components of the feeding mechanism did not double as water temperature increased from 20 °C to 30 °C; and (2) thermal sensitivity (Q10 values) for gape, hyoid, lower-jaw rotation, and cranial rotation velocities at 20 °C and 30 °C ranged from 0.56 to 1.44 in all three species. With the exception of lower-jaw rotation, Q10 values were significantly less than the expected Q10 = 2.0, indicating that feeding kinematics remains consistent despite the change in environmental temperature. It is conceivable that the ability to maintain peak performance at different temperatures helps facilitate the spread of invasive fishes globally.
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