26 research outputs found
Efficacy of ERL-4221 as an ovotoxin for feral pigs (\u3ci\u3eSus scrofa\u3c/i\u3e)
Context. The expansion of feral pig populations across the United States has increased the occurrence of damage and damage complaints.Newtechniques are needed to more effectively manage feral pig damage, including the development of fertility control agents.
Aims. We aimed to assess the ovotoxic properties of ERL-4221 as a candidate fertility control agent for feral pigs.
Methods. We conducted two palatability trials to determine ERL-4221 acceptance and one experimental trial with ERL- 4221 at the captive wildlife facility of Texas A&M University-Kingsville during 2008. Our experimental trial had three treatments, a control containing no ERL-4221, baits containing 16.0 mg ERL-4221 kgâ1 bodyweight for 10 days, and baits containing 16.0 mg ERL-4221 kgâ1 bodyweight for 20 days.
Key results. Final body mass, total ovary mass, number of follicles and number of corpora lutea did not differ between treatments.
Conclusions. We did not find it efficacious to orally deliver ERL-4221 to feral pigs to reduce fertility. Oral delivery is the most practical, cost-effective means of delivering fertility control agents to feral pigs and development of additional fertility control strategies are needed.
Implications. Unless ovotoxic effects of ERL-4221 can be identified in feral pigs, along with a successful means of administration, other fertility control strategies may need to be explored, such as oocyte-secreted proteins that regulate follicular development
The Faint Optical Afterglow and Host Galaxy of GRB 020124: Implications for the Nature of Dark Gamma-ray Bursts
We present ground-based optical observations of GRB 020124 starting 1.6 hr after the burst, as well as subsequent Very Large Array and Hubble Space Telescope (HST) observations. The optical afterglow of GRB 020124 is one of the faintest afterglows detected to date, and it exhibits a relatively rapid decay, Fv â t-1.60±0.04, followed by further steepening. In addition, a weak radio source was found coincident with the optical afterglow. The HST observations reveal that a positionally coincident host galaxy must be the faintest host to date, R âł 29.5 mag. The afterglow observations can be explained by several models requiring little or no extinction within the host galaxy, AVhost â 0-0.9 mag. These observations have significant implications for the interpretation of the so-called dark bursts (bursts for which no optical afterglow is detected), which are usually attributed to dust extinction within the host galaxy. The faintness and relatively rapid decay of the afterglow of GRB 020124, combined with the low inferred extinction, indicate that some dark bursts are intrinsically dim and not dust obscured. Thus, the diversity in the underlying properties of optical afterglows must be observationally determined before substantive inferences can be drawn from the statistics of dark bursts.F. A. H. acknowledges support from a Presidential Early
Career award. S. R. K. and S. G. D. thank the NSF for support. R. S. is grateful for support from a NASA ATP grant.
R. S. and T. J. G. acknowledge support from the Sherman
Fairchild Foundation. J. C. W. acknowledges support from
NASA grant NAG 59302. K. H. is grateful for Ulysses support under JPL contract 958056 and for IPN support under
NASA grants FDNAG 5-11451 and NAG 5-17100. Support for Proposal HST-GO-09180.01-A was provided by
NASA through a grant from the Space Telescope Science
Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555
The protein-vesicle network of autophagy.
The biogenesis of autophagosomes entails the nucleation and growth of a double-membrane sheet, the phagophore, which engulfs cytosol for delivery to the lysosome. Genetic studies have identified a class of Atg proteins that are essential for the process, yet the molecular mechanism of autophagosome biogenesis has been elusive. Proteomic, structural, super-resolution imaging, and biochemical reconstitution experiments have begun to fill in some of the gaps. This review describes progress and prospects for obtaining a four-dimensional network model of the nucleation and growth of the phagophore
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The protein-vesicle network of autophagy.
The biogenesis of autophagosomes entails the nucleation and growth of a double-membrane sheet, the phagophore, which engulfs cytosol for delivery to the lysosome. Genetic studies have identified a class of Atg proteins that are essential for the process, yet the molecular mechanism of autophagosome biogenesis has been elusive. Proteomic, structural, super-resolution imaging, and biochemical reconstitution experiments have begun to fill in some of the gaps. This review describes progress and prospects for obtaining a four-dimensional network model of the nucleation and growth of the phagophore
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Regulation of LC3 lipidation by the autophagy-specific class III phosphatidylinositol-3 kinase complex.
Autophagy is a conserved eukaryotic pathway critical for cellular adaptation to changes in nutrition levels and stress. The class III phosphatidylinositol (PI)3-kinase complexes I and II (PI3KC3-C1 and -C2) are essential for autophagosome initiation and maturation, respectively, from highly curved vesicles. We used a cell-free reaction that reproduces a key autophagy initiation step, LC3 lipidation, as a biochemical readout to probe the role of autophagy-related gene (ATG)14, a PI3KC3-C1-specific subunit implicated in targeting the complex to autophagy initiation sites. We reconstituted LC3 lipidation with recombinant PI3KC3-C1, -C2, or various mutant derivatives added to extracts derived from a CRISPR/Cas9-generated ATG14-knockout cell line. Both complexes C1 and C2 require the C-terminal helix of VPS34 for activity on highly curved membranes. However, only complex C1 supports LC3 lipidation through the curvature-targeting amphipathic lipid packing sensor (ALPS) motif of ATG14. Furthermore, the ALPS motif and VPS34 catalytic activity are required for downstream recruitment of WD-repeat domain phosphoinositide-interacting protein (WIPI)2, a protein that binds phosphatidylinositol 3-phosphate and its product phosphatidylinositol 3, 5-bisphosphate, and a WIPI-binding protein, ATG2A, but do not affect membrane association of ATG3 and ATG16L1, enzymes contributing directly to LC3 lipidation. These data reveal the nuanced role of the ATG14 ALPS in membrane curvature sensing, suggesting that the ALPS has additional roles in supporting LC3 lipidation
Teaching quality improvement in Tanzania: a model of inter-professional partnership for global health development
Background: Education is a universal need in health care and a tool for quality improvement. We developed a two-day medical education conference in Iringa, Tanzania, that has now evolved to teach the basics of quality improvement to an inter-professional audience from the 28 hospitals in the southern zone of the Tanzania Christian Social Services Commission (CSSC). Methods: We describe the planning, budget, implementation, evolution and evaluation of this on-going medical education conference. Representatives from medicine, nursing, pharmacy and administration from all 28 hospitals were invited to attend. Attendees evaluated the conference and individual lectures on a 5 point scale. In addition, attendees were asked to rate the most important learning aspect of the conference. Results: Over 100 Tanzanian health professionals and administrators from the 28 hospitals in the southern zone of the CSSC attended. Evaluation forms were completed by 82 attendees. The 2016 conference received an overall rating of 4.0 on a 5 point scale. The individual lectures received an overall rating of 4.2 on a 5 point scale. Quality improvement techniques and co-leadership topics were rated as most useful by attendees. Conclusion: We provide a framework for developing a medical education conference that can be replicated in other settings. Teaching the basics of quality improvement by having hospital leadership teams develop individual quality improvement projects is a highly useful method of instruction
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Regulation of LC3 lipidation by the autophagy-specific class III phosphatidylinositol-3 kinase complex.
Autophagy is a conserved eukaryotic pathway critical for cellular adaptation to changes in nutrition levels and stress. The class III phosphatidylinositol (PI)3-kinase complexes I and II (PI3KC3-C1 and -C2) are essential for autophagosome initiation and maturation, respectively, from highly curved vesicles. We used a cell-free reaction that reproduces a key autophagy initiation step, LC3 lipidation, as a biochemical readout to probe the role of autophagy-related gene (ATG)14, a PI3KC3-C1-specific subunit implicated in targeting the complex to autophagy initiation sites. We reconstituted LC3 lipidation with recombinant PI3KC3-C1, -C2, or various mutant derivatives added to extracts derived from a CRISPR/Cas9-generated ATG14-knockout cell line. Both complexes C1 and C2 require the C-terminal helix of VPS34 for activity on highly curved membranes. However, only complex C1 supports LC3 lipidation through the curvature-targeting amphipathic lipid packing sensor (ALPS) motif of ATG14. Furthermore, the ALPS motif and VPS34 catalytic activity are required for downstream recruitment of WD-repeat domain phosphoinositide-interacting protein (WIPI)2, a protein that binds phosphatidylinositol 3-phosphate and its product phosphatidylinositol 3, 5-bisphosphate, and a WIPI-binding protein, ATG2A, but do not affect membrane association of ATG3 and ATG16L1, enzymes contributing directly to LC3 lipidation. These data reveal the nuanced role of the ATG14 ALPS in membrane curvature sensing, suggesting that the ALPS has additional roles in supporting LC3 lipidation
DNA Hairpins Containing the Cytidine Analog Pyrrolo-dC: Structural, Thermodynamic, and Spectroscopic Studies
Structures formed by single-strand DNA have become increasingly interesting because of their roles in a number of biological processes, particularly transcription and its regulation. Of particular importance is the fact that antitumor drugs such as Actinomycin D can selectively bind DNA hairpins over fully paired, double-strand DNA. A new fluorescent base analog, pyrrolo-deoxycytidine (PdC), can now be routinely incorporated into single-strand DNA. The fluorescence of PdC is particularly useful for studying the formation of single-strand DNA in regions of double-strand DNA. The fluorescence is quenched when PdC is paired with a complementary guanine residue, and thus is greatly enhanced upon formation of single-strand DNA. Hence, any process that results in melting or opening of DNA strands produces an increase in the fluorescence intensity of this base analog. In this study we measured the structural effects of incorporating PdC into DNA hairpins, and the effect of this incorporation on the binding of the hairpins by a fluorescent analog of the drug Actinomycin D. Two hairpin DNAs were used: one with PdC in the stem (basepaired) and one with PdC in the loop (unpaired). The thermal stability, 7-aminoactinomycin D binding, and three-dimensional structures of PdC incorporated into these DNA hairpins were all quite similar as compared to the hairpins containing an unmodified dC residue. Fluorescence lifetime measurements indicate that two lifetimes are present in PdC, and that the increase in fluorescence of the unpaired PdC residue compared to the basepaired PdC is due to an increase in the contribution of the longer lifetime to the average fluorescence lifetime. Our data indicate that PdC can be used effectively to differentiate paired and unpaired bases in DNA hairpin secondary structures, and should be similarly applicable for related structures such as cruciforms and quadruplexes. Further, our data indicate that PdC can act as a fluorescence resonance energy transfer donor for the fluorescent drug 7-aminoactinomycin D