Meristic and Morphometric Differences in Populations of Rivulus marmoratus

Rivulus marmoratus (Pisces: Aplocheilidae) is a small cyprinodontid found in mangroves of the western tropical Atlantic and is the only known self-fertilizing, hermaphroditic vertebrate. Populations normally consist of genetically diverse groups of homozygous clones. Rivulus marmoratus has the widest range of any member of the genus (southern Brazil to central Florida) and is the only marine representative of the genus. There has been considerable speculation about the origin of the species in an otherwise sexually reproducing genus and family. Although well studied in the laboratory, few specimens have been collected from the wild until recently. This study examined meristic and morphometric differences among 12 widespread populations and among individual clonal lineages reared in the laboratory. Thirty-two meristic and morphometric characters in 187 fish (ranging from Brazil to Florida) were examined with univariate and multivariate statistics for determination of overall differences among populations. To control for possible environmental effects, offspring of eight clones from two populations (Belize and Florida) were reared at 25 C and similarly analyzed. All characters with the exception of pectoral fin rays were significantly different among wild populations. In addition, Belizean male fish differed from hermaphrodites in several morphometric characters. Fish reared at constant temperature also displayed significant differences, indicating a probable genetic component to differences in wild fish. The multivariate analyses also confirmed considerable heterogeneity among R. marmoratus. Overall, fish from Brazil, the Florida Everglades, Belize, and Honduras appear to be distinct from the other groups. The characters that contributed most to group delineations were number of precaudal vertebrae, distance from pelvic fin origin to anal fin origin, pectoral fin length, and number of branched caudal rays. Discriminant function analysis was able to classify the fish reared at 25 C to individual clonal heritage, although with a different set of characters than in wild fish

An Acyl-Linked Dimer of Daptomycin Is Strongly Inhibited by the Bacterial Cell Wall

This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publi-cation in ACS Infectious Diseases,© American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/doi/full/10.1021/acsinfecdis.7b00019.The lipopeptide antibiotic daptomycin is active against Gram-positive pathogens. It permeabilizes bacterial cell membranes, which involves the formation of membrane-associated oligomers. We here studied a dimer of daptomycin whose two subunits were linked through a bivalent aliphatic acyl chain. Unexpectedly, the dimer had very low activity on vegetative Staphylococcus aureus and Bacillus subtilis cells. However, activity resembled that of monomeric daptomycin on liposomes and on B. subtilis L-forms. These findings underscore the importance of the bacterial cell wall in daptomycin resistance.NSERC operating grants to M.P. (250265-2013) and S.T. (155283-2012)

The action mechanism of daptomycin

The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.bmc.2016.05.052 © 2016.Daptomycin is a lipopeptide antibiotic produced by the soil bacterium Streptomyces roseosporus that is clinically used to treat severe infections with Gram-positive bacteria. In this review, we discuss the mode of action of this important antibiotic. Although daptomycin is structurally related to amphomycin and similar lipopeptides that inhibit peptidoglycan biosynthesis, experimental studies have not produced clear evidence that daptomycin shares their action mechanism. Instead, the best characterized effect of daptomycin is the permeabilization and depolarization of the bacterial cell membrane. This activity, which can account for daptomycin's bactericidal effect, correlates with the level of phosphatidylglycerol (PG) in the membrane. Accordingly, reduced synthesis of PG or its increased conversion to lysyl-PG promotes bacterial resistance to daptomycin. While other resistance mechanisms suggest that daptomycin may indeed directly interfere with cell wall synthesis or cell division, such effects still await direct experimental confirmation. Daptomycin's complex structure and biosynthesis have hampered the analysis of its structure activity relationships. Novel methods of total synthesis, including a recent one that is carried out entirely on a solid phase, will enable a more thorough and systematic exploration of the sequence space

The Emerging Scholars Issue: Insights on Teaching and Leading through Reshaping Policy and Practice

The Emerging Scholars program began at the 2019 Texas-NAME conference with five graduate students, four of which were enrolled in a doctoral program. Students participated in preconference workshops on establishing a research agenda, understanding academia and higher education institutions, and creating a network as an education researcher. Since its inception, the program has continued introducing students to collaborations and publication opportunities through Texas-NAME. This special issue provides doctoral students (some of whom have since graduated) with an opportunity to be single-authors in their scholar. Organized in three distinct sections, readers will be exposed to research and policy briefs and critical reflections that center on the experiences of difference to provide educational access, equity, and opportunity to historically minoritized populations

The Emerging Scholars Issue: Continuous Learning Through a Personal and Professional Lens

The Emerging Scholars program offers ongoing mentoring, personalized feedback, and opportunities for individual and collaborative scholarly development. Participants are encouraged to present at the Texas-NAME annual conference and publish their research in the Journal of Multicultural Affairs\u27 special issue for Emerging Scholars. The publication process is supportive, beginning with mentorship and discussions on manuscript organization. Peer review involves the mentor, a contributing author, and previous emerging scholars as reviewers, fostering a collaborative environment that promotes learning and idea development. The issue\u27s topics revolve around challenges faced by students of color, exploring issues such as out-of-school suspensions, the impact of COVID-19 on education, Indigenous knowledge, rural education policy, cultural gaps, class start times, and critical race theory in schools. Authors delved into topics of personal interest and experiences that influenced their research, all with the common goal of improving educational equality. The special issue serves as a platform for scholars to grow and collaborate, fostering efforts towards positive change in the academic landscape for every student\u27s benefit

Measurement and models accounting for cell death capture hidden variation in compound response.

Cancer cell sensitivity or resistance is almost universally quantified through a direct or surrogate measure of cell number. However, compound responses can occur through many distinct phenotypic outcomes, including changes in cell growth, apoptosis, and non-apoptotic cell death. These outcomes have divergent effects on the tumor microenvironment, immune response, and resistance mechanisms. Here, we show that quantifying cell viability alone is insufficient to distinguish between these compound responses. Using an alternative assay and drug-response analysis amenable to high-throughput measurement, we find that compounds with identical viability outcomes can have very different effects on cell growth and death. Moreover, additive compound pairs with distinct growth/death effects can appear synergistic when only assessed by viability. Overall, these results demonstrate an approach to incorporating measurements of cell death when characterizing a pharmacologic response

Introduction to Special Issue of \u3ci\u3eJournal of Defense Modeling and Simulation\u3c/i\u3e: Novel Approaches to Defense and Military Modeling and Simulation

Developing solutions to complex problems in government and industry is a daunting task that often requires tremendous investment in time and resources to solve. Modeling and simulation (M&S) has incredible potential to streamline development and cut costs by conducting virtual experiments that give insight into performance under various test conditions. As many program managers in the federal acquisition process can attest, realistic testing of live equipment in an operational environment can be some of the most expensive parts of a development program. M&S can provide insight into mission success of yetto- bedesigned systems without the need to actually build and test the system in the real world. Similarly, M&S tools can evaluate human effectiveness under various scenarios while only risking the virtual lives of avatars. When properly applied, M&S capabilities provide critical insight that allows leaders to make smart decisions about how to accomplish the mission and increase human performance more quickly and at lower cost and risk than reliance on real-world testing. Throughout this special issue, we examine a variety of novel M&S concepts that promise to deliver simulation results to the defense and military community that positively impact system-level mission studies and human effectiveness research. These M&S tools not only affect the defense and military community, but can also have application to a wide variety of government and industry users with needs to solve similar problem sets. Whether the end goal is cost savings, operational analysis or refinement of sub-components, the M&S concepts described in this special issue testify to the power that these tools can provide to help decision makers efficiently allocate scarce resources and provide improved performance of humans and the systems that they operate in the long run