Restoration of Northwest Florida Sandhills Through Harvest of Invasive Pinus clausa

Across much of the southeastern U.S.A., sandhills have become dominated by hardwoods or invasive pine species following logging of Pinus palustris (longleaf pine) and fire suppression. At Eglin Air Force Base where this study was conducted, Pinus clausa (sand pine) has densely colonized most southeastern sandhill sites, suppressing groundcover vegetation. The objectives of this study were: to determine if suppressed groundcover vegetation recovers following the removal of P. clausa; to compare species composition and abundance in removal plots with that in reference, high quality sandhills; to test the assumption that recolonization by P. clausa seedlings decreases with proximity to the centers of removal plots; and to measure the survival of containerized P. palustris seedlings that were planted on P. clausa removal plots. One year post‐removal (1995), the number of plant species decreased by 50%, but then increased by 100% from 1995 to 1997, followed by a small reduction in 1998. The number of plant species was greater in reference plots than in removal plots prior to 1997. Eighty‐five percent of the original species were recorded 4 years post‐harvest in removal plots. Shrubs and large trees remained at low density after harvest. Densities of graminoids, legumes, other forbs, woody vines, and small trees increased after harvest. Plant densities of all life forms, except woody vines, were greater in reference plots than in removal plots. The density of recolonizing P. clausa seedlings 2–4 years post‐harvest significantly decreased with increasing proximity to the centers of removal plots. On average, 80% of planted P. palustris seedlings survived their first 2 years. Harvest of P. clausa followed by fire and the planting of P. palustris is a reasonably effective restoration approach in invaded sandhills. However, supplementary plantings of some herbaceous species may be necessary for full restoration.     

The apparent molecular size of native alpha-crystallin B in non-lenticular tissues

The apparent molecular size of the native alpha-crystallin B in cytosol preparations from rat heart, brain and retina was determined by gel permeation chromatography, detecting the protein by immunochemical assay (ELISA), using an alpha-crystallin specific antiserum. Native alpha-crystallin from cytosol preparations of rat lens cortex was used as a reference. alpha-Crystallin B present in all three cytosol preparations from non-lenticular tissues eluted in a single symmetrical peak, with the same elution volume as alpha-crystallin from lens cortex cytosol preparations, corresponding to an apparent average molecular size of 0.8 x 10(6) Da. No other species could be detected. The results indicate that the alpha-crystallin aggregates characterized by an apparent average molecular mass of 0.8 x 10(6) Da, and considered to be the native, physiological form of the protein in the lens, are indeed not specific to lens tissue. Furthermore, the size of these alpha-crystallin aggregates is independent of their polypeptide composition. Aggregates found in the lens, composed of alpha A and alpha B polypeptides and their respective phosphorylated forms alpha Ap and alpha Bp, are similar in size to those found in heart, brain and retina, containing the alpha B but not the alpha A polypeptide.     

Endothelin stimulates phosphatidic acid formation in cultured rat mesangial cells: role of a protein kinase C-regulated phospholipase D.

We have previously reported that endothelin-1 stimulates phospholipase C-induced hydrolysis of phosphatidylinositol-4,5-bisphosphate. Other signal transduction pathways that hydrolyze alternative phospholipids through phospholipase D may also mediate endothelin-stimulated cellular responses. We initially evaluated endothelin-dependent generation of 32P-phosphatidic acid as an indirect indication of phospholipase D activity in rat mesangial cells. Endothelin (10(-7) M) induced an elevation of phosphatidic acid that was maximal at 15 min and persisted upward of 60 min. Pretreatment with the diacylglycerol-kinase inhibitor, R59022, did not reduce formation of endothelin-stimulated 32P-phosphatidic acid, demonstrating that the sequential actions of phospholipase C/diacylglycerol kinase do not contribute to endothelin-stimulated phosphatidic acid formation. We next conclusively identified a role for phospholipase D in the generation of phosphatidic acid by assessing the formation of 3H-phosphatidylethanol from 3H-alkyl lyso glycerophosphocholine and exogenous ethanol. Endothelin stimulated 3H-alkyl phosphatidylethanol formation in the presence but not the absence of 0.5% ethanol. Also, endothelin induced a concomitant elevation of 3H-alkyl-phosphatidic acid that was significantly reduced when the cells were exposed to exogenous ethanol, reflecting the formation of phosphatidylethanol. In addition, endothelin stimulated the release of 3H-choline and 3H-ethanolamine, demonstrating that additional phospholipids may serve as substrates for phospholipase D. Phorbol esters and synthetic diglycerides mimicked the effects of endothelin to stimulate phospholipase D and inhibitors of protein kinase C significantly reduced endothelin-stimulated phospholipase D. In addition, endothelin did not stimulate phosphatidylethanol formation in protein kinase C down-regulated cells. The calcium ionophore, ionomycin, did not stimulate phospholipase D and mesangial cells pretreated with BAPTA to chelate cytosolic calcium did not show a diminished endothelin-stimulated phospholipase D. Thus these data demonstrate that mesangial cells possess a protein kinase C-regulated phospholipase D activity that can be stimulated with endothelin.     

Lung Epithelial Cells Coordinate Innate Lymphocytes and Immunity against Pulmonary Fungal Infection

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Structural analysis of human immunodeficiency virus type 1 Gag protein interactions, using cysteine-specific reagents.

We have examined structural interactions of Gag proteins in human immunodeficiency virus type 1 (HIV-1) particles by utilizing cysteine mutagenesis and cysteine-specific modifying reagents. In immature protease-minus but otherwise wild-type (wt) particles, precursor Pr55Gag proteins did not form intermolecular cystines naturally but could be cross-linked at cysteines, and cross-linking appeared to occur across nucleocapsid (NC) domains. Capsid (CA) proteins in wt mature viruses possess cysteines near their carboxy termini at gag codons 330 and 350, but these residues are not involved in natural covalent intermolecular bonds, nor can they be intermolecularly cross-linked by using the membrane-permeable cross-linker bis-maleimido hexane. The cysteine at gag codon 350 (C-350) is highly reactive to thiol-specific modifying reagents, while the one at codon 330 (C-330) appears considerably less reactive, even in the presence of ionic detergent. These results suggest that the HIV-1 CA C terminus forms an unusually stable conformation. Mutagenesis of C-350 to a serine residue in the mutant C350S (C-350 changed to serine) virtually eliminated particle assembly, attesting to the importance of this region. We also examined a C330S mutant, as well as mutants in which cysteines were created midway through the capsid domain or in the C-terminal section of the major homology region. All such mutants appeared wt on the basis of biochemical assays but showed greatly reduced infectivities, indicative of a postassembly, postprocessing replicative block. Interestingly, capsid proteins of mature major homology region mutant particles could be cysteine cross-linked, implying either that these mutations permit cross-linking of the native C-terminal CA cysteines or that major homology regions on neighbor capsid proteins are in close proximity in mature virions.     

Ecological Theory and Community Restoration Ecology

Community ecological theory may play an important role in the development of a science of restoration ecology. Not only will the practice of restoration benefit from an increased focus on theory, but basic research in community ecology will also benefit. We pose several major thematic questions that are relevant to restoration from the perspective of community ecological theory and, for each, identify specific areas that are in critical need of further research to advance the science of restoration ecology. We ask, what are appropriate restoration endpoints from a community ecology perspective? The problem of measuring restoration at the community level, particularly given the high amount of variability inherent in most natural communities, is not easy, and may require a focus on restoration of community function (e.g., trophic structure) rather than a focus on the restoration of particular species. We ask, what are the benefits and limitations of using species composition or biodiversity measures as endpoints in restoration ecology? Since reestablishing all native species may rarely be possible, research is needed on the relationship between species richness and community stability of restored sites and on functional redundancy among species in regional colonist “pools.” Efforts targeted at restoring system function must take into account the role of individual species, particularly if some species play a disproportionate role in processing material or are strong interactors. We ask, is restoration of habitat a sufficient approach to reestablish species and function? Many untested assumptions concerning the relationship between physical habitat structure and restoration ecology are being made in practical restoration efforts. We need rigorous testing of these assumptions, particularly to determine how generally they apply to different taxa and habitats. We ask, to what extent can empirical and theoretical work on community succession and dispersal contribute to restoration ecology? We distinguish systems in which succession theory may be broadly applicable from those in which it is probably not. If community development is highly predictable, it may be feasible to manipulate natural succession processes to accelerate restoration. We close by stressing that the science of restoration ecology is so intertwined with basic ecological theory that practical restoration efforts should rely heavily on what is known from theoretical and empirical research on how communities develop and are structured over time.     

What can be concluded from the Oxcheck and British family heart studies: commentary on cost effectiveness analyses.

OBJECTIVES--To provide a commentary on the economic evaluations of the Oxcheck and British family heart studies: direct comparison of their relative effectiveness and cost effectiveness; comparisons with other interventions; and consideration of problems encountered. DESIGN--Modelling from cost and effectiveness data to estimate of cost per life year gained. SUBJECTS--Middle aged men and women. INTERVENTIONS--Screening for cardiovascular risk factors followed by appropriate lifestyle advice and drug intervention in general practice, and other primary coronary risk management strategies. MAIN OUTCOME MEASURES--Life years gained; cost per life year gained. RESULTS--Depending on the assumed duration of risk reduction, the programme cost per discounted life year gained ranged from 34,800 pounds for a 1 year duration to 1500 pounds for 20 years for the British family heart study and from 29,300 pounds to 900 pounds for Oxcheck. These figures exclude broader net clinical and cost effects and longer term clinical and cost effects other than coronary mortality. CONCLUSIONS--Despite differences in underlying methods, the estimates in the two economic analyses of the studies can be directly compared. Neither study was large enough to provide precise estimates of the overall net cost. Modelling to cost per life year gained provides more readily interpretable measures. These estimates emphasise the importance of the relatively weak evidence on duration effect. Only if the effect lasts at least five years is the Oxcheck programme likely to be cost effective. The effect must last for about 10 years to justify the extra cost associated with the British family heart study.     

Whole-Genome Sequencing Analysis Accurately Predicts Antimicrobial Resistance Phenotypes in Campylobacter spp.

The objectives of this study were to identify antimicrobial resistance genotypes for Campylobacter and to evaluate the correlation between resistance phenotypes and genotypes using in vitro antimicrobial susceptibility testing and whole-genome sequencing (WGS). A total of 114 Campylobacter species isolates (82 C. coli and 32 C. jejuni) obtained from 2000 to 2013 from humans, retail meats, and cecal samples from food production animals in the United States as part of the National Antimicrobial Resistance Monitoring System were selected for study. Resistance phenotypes were determined using broth microdilution of nine antimicrobials. Genomic DNA was sequenced using the Illumina MiSeq platform, and resistance genotypes were identified using assembled WGS sequences through blastx analysis. Eighteen resistance genes, including tet(O), bla_OXA-61, catA, lnu(C), aph(2″)-Ib, aph(2″)-Ic, aph(2′)-If, aph(2″)-Ig, aph(2″)-Ih, aac(6′)-Ie-aph(2″)-Ia, aac(6′)-Ie-aph(2″)-If, aac(6′)-Im, aadE, sat4, ant(6′), aad9, aph(3′)-Ic, and aph(3′)-IIIa, and mutations in two housekeeping genes (gyrA and 23S rRNA) were identified. There was a high degree of correlation between phenotypic resistance to a given drug and the presence of one or more corresponding resistance genes. Phenotypic and genotypic correlation was 100% for tetracycline, ciprofloxacin/nalidixic acid, and erythromycin, and correlations ranged from 95.4% to 98.7% for gentamicin, azithromycin, clindamycin, and telithromycin. All isolates were susceptible to florfenicol, and no genes associated with florfenicol resistance were detected. There was a strong correlation (99.2%) between resistance genotypes and phenotypes, suggesting that WGS is a reliable indicator of resistance to the nine antimicrobial agents assayed in this study. WGS has the potential to be a powerful tool for antimicrobial resistance surveillance programs.     

Effects of Topically Applied Vitamin D during Corneal Wound Healing

Vitamin D is an important regulator of immune function and largely acts to dampen chronic inflammatory events in a variety of tissues. There is also accumulating evidence that vitamin D acts to enhance initial inflammation, beneficial during both infection and wound healing, and then promotes resolution and prevention of chronic, damaging inflammation. The current study examines the effect of topical vitamin D in a mouse of model of corneal epithelial wound healing, where acute inflammation is necessary for efficient wound closure. At 12 and 18 hours post-wounding, vitamin D treatment significantly delayed wound closure by ~17% and increased infiltration of neutrophils into the central cornea. Basal epithelial cell division, corneal nerve density, and levels of VEGF, TGFβ, IL-1β, and TNFα were unchanged. However, vitamin D increased the production of the anti-microbial peptide CRAMP 12 hours after wounding. These data suggest a possible role for vitamin D in modulating corneal wound healing and have important implications for therapeutic use of vitamin D at the ocular surface.