A guide to the winged aphids (Homoptera) of Costa Rica

This guide is a compilation of limited morphological and biological information on the winged morphs of 60 species of aphids that have been collected in Costa Rica. It should not be viewed as a definitive taxonomic treatise on the aphids of Costa Rica, rather it is a tool that can be used to assist in research on the biology, host plant relationships, taxonomy, and virus transmission capabilities of aphids. Each species is covered in an identical manner. Morphological and biological information is provided in both Spanish and English as well as photographs of slide mounted specimens. Keys are provided to help the user in identifying the species. Most of the specimens examined were taken in traps associated with epidemiological studies. Limited field collecting has generated host records and these have been added to a list of the aphids of Central America that was compiled by Pamela Anderson and appended in the guide with her permission. The authors hope that this book will be useful to entomologists in Costa Rica and Central America.     

Optical Coherence Tomography of Pulmonary Arterial Walls in Humans and Pigs (Sus scrofa domesticus)

Pulmonary arterial hypertension (PAH) is a devastating disorder characterized by progressive elevation of the pulmonary pressures that, in the absence of therapy, results in chronic right-heart failure and premature death. The vascular pathology of PAH is characterized by progressive loss of small (diameter, less than 50 μm) peripheral pulmonary arteries along with abnormal medial thickening, neointimal formation, and intraluminal narrowing of the remaining pulmonary arteries. Vascular pathology correlates with disease severity, given that hemodynamic effects and disease outcomes are worse in patients with advanced compared with lower-grade lesions. Novel imaging tools are urgently needed that demonstrate the extent of vascular remodeling in PAH patients during diagnosis and treatment monitoring. Optical coherence tomography (OCT) is a catheter-based intravascular imaging technique used to obtain high-resolution 2D and 3D cross-sectional images of coronary arteries, thus revealing the extent of vascular wall pathology due to diseases such as atherosclerosis and in-stent restenosis; its utility as a diagnostic tool in the assessment of the pulmonary circulation is unknown. Here we show that OCT provides high-definition images that capture the morphology of pulmonary arterial walls in explanted human lungs and during pulmonary arterial catheterization of an adult pig. We conclude that OCT may facilitate the evaluation of patients with PAH by disclosing the degree of wall remodeling present in pulmonary vessels. Future studies are warranted to determine whether this information complements the hemodynamic and functional assessments routinely performed in PAH patients, facilitates treatment selection, and improves estimates of prognosis and outcome.Abbreviations: OCT, optical coherence tomography; PAC, pulmonary artery catheter; PAH, pulmonary arterial hypertensionPulmonary arterial hypertension (PAH) is a devastating disorder characterized by progressive elevation of pulmonary pressures that, when untreated, can lead to chronic right heart failure and death.¹⁴ The vascular pathology of PAH is characterized by neointimal formation, medial thickening, intravascular thrombi and, in severe cases, intravascular clusters of disorganized endothelial cells that give rise to tortuous endovascular channels.⁸ Most of the early vascular lesions are found in small (diameter, less than 50 μm) pulmonary arteries. However, as the disease advances, pulmonary arteries (diameter, 50 μm or larger) proximal to these lesions also display evidence of luminal narrowing and medial thickening.^7,8,15 Most patients with PAH are younger than those with chronic systemic vascular disorders (that is, coronary artery disease, peripheral vascular disease, systemic hypertension), whose vascular pathology involves mostly large to medium-sized arteries. However, both patient populations demonstrate various pathologic features, including vascular smooth-cell accumulation, neointimal formation, inflammation, luminal narrowing, and alterations in the composition of the extracellular matrix.^6,17The only definite way to diagnose PAH is through right heart catheterization to directly measure the pressure in the pulmonary circulation. Although pulmonary angiography during right heart catheterization cannot be used to diagnose PAH, it provides supportive evidence of PAH by demonstrating significant peripheral small vessel loss and luminal narrowing in the remaining central vessels. Angiography can help clinicians visualize pulmonary vessels in real time, but this diagnostic technique has important limitations. The use of ionized contrast can cause allergic reactions and may trigger acute renal failure due to contrast-induced nephropathy.²⁶ In addition, pulmonary angiography provides information regarding gross vessel appearance and small vessel perfusion but not about the state of vascular wall remodeling or the extent of luminal narrowing associated with PAH at any stage.^5,16 Therefore, imaging techniques are urgently needed that complement the hemodynamic information obtained via right heart catheterization with a safe and reproducible method to assess vascular wall pathology, thereby allowing clinicians to correlate the clinical evolution of PAH with the progression of vascular pathology.The last decade has seen tremendous progress in the development of intravascular imaging modalities that can identify patients at risk for developing complications related to systemic vascular disease and therefore prevent disease-related morbidity and mortality.⁴ One such modality is optical coherence tomography (OCT), an imaging technique that uses a thin (diameter, 1.0 mm) wire and near-infrared light to capture micrometer-resolution, 3D images from within optical scattering media (for example, biologic tissue).¹ Superior to other intravascular imaging techniques, OCT is frequently used in patients with coronary artery disease, where it provides high-resolution images of the coronary arterial wall that correlate highly with pathology seen in explanted vessels.^10,11,21 To date, several small studies have demonstrated the application of OCT to the evaluation of vascular remodeling in both idiopathic PAH and chronic thromboembolic PAH.^7,21 However, despite OCT''s obvious advantages in the characterization of vascular remodeling in discrete segments of the pulmonary circulation, whether OCT provides anatomic information across the length of the pulmonary artery has not been tested.Here, we report the capacity of OCT to obtain both longitudinal and cross-sectional images that provide accurate anatomic information on healthy pulmonary arteries in explanted human lungs and during the pulmonary arterial catheterization of a live adult pig (Sus scrofa domesticus).     

Specialization clines in the pollination systems of agaves (Agavaceae) and columnar cacti (Cactaceae): A phylogenetically controlled meta-analysis

The biogeography of plant-animal interactions is a novel topic on which many disciplines converge (e.g., reproductive biology, biogeography, and evolutionary biology). Narrative reviews have indicated that tropical columnar cacti and agaves have highly specialized pollination systems, while extratropical species have generalized systems. However, this dichotomy has never been quantitatively tested. We tested this hypothesis using traditional and phylogenetically informed meta-analysis. Three effect sizes were estimated from the literature: diurnal, nocturnal, and hand cross-pollination (an indicator of pollen limitation). Columnar cactus pollination systems ranged from purely bat-pollinated in the tropics to generalized pollination, with diurnal visitors as effective as nocturnal visitors in extratropical regions; even when phylogenetic relatedness among species is taken into account. Metaregressions identified a latitudinal increase in pollen limitation in columnar cacti, but this increase was not significant after correcting for phylogeny. The currently available data for agaves do not support any latitudinal trend. Nectar production of columnar cacti varied with latitude. Although this variation is positively correlated with pollination by diurnal visitors, it is influenced by phylogeny. The degree of specificity in the pollination systems of columnar cacti is heavily influenced by ecological factors and has a predictable geographic pattern.     

The Primary Lower Gypsum in the Mediterranean: A new facies interpretation for the first stage of the Messinian salinity crisis

The detailed facies and physical stratigraphic analysis of the Primary Lower Gypsum in the Mediterranean indicates a surprising bed-by-bed correlation at basin-scale (Spain, Italy, Hellenic arc and Cyprus arc), that is tuned to the orbital calibration for the first stage of the Messinian salinity crisis from 5.96 to 5.61 Ma ago. A total of 16, precessionally-controlled, gypsum cycles were deposited rapidly in less than 350 ka, forming sequences up to 300 m thick. The lack of subaerial exposure features and the common facies associations and stacking pattern for sections located thousands of kilometers apart in different geological settings indicates a modest depositional depth, not extremely shallow. Selenite deposition occurred only at the bottom of restricted marginal basins less than 200 m deep, while no gypsum could precipitate in the deeper euxinic Mediterranean portions where only thin and barren shale/dolostone couplets formed. The lowermost selenite beds pass laterally to dolomite-rich limestones interbedded with barren euxinic shales in poorly oxygenated settings, indicating that the gypsum sedimentation was diachronous and did not necessarily mark the onset on the Messinian salinity crisis.Evaporite facies sequences (EF1 to 8) within individual gypsum beds show small-scale, subaqueous sedimentary cycles that mimic regressive-transgressive cycles: a) initial evaporite precipitation at relatively low supersaturation produced the massive selenite (facies EF3) in a relatively deep setting; b) continuous evaporation and drawdown by oscillating brine level formed the banded selenite (EF4) at the aridity acme of the precessionally-controlled cycle; c) general progressive brine level rise with strong brine flow led to the formation of large selenite supercones branching laterally (supercones in Spain and branching selenite, EF5, in the rest of the Mediterranean); and d) flooding by undersaturated continental water terminated gypsum precipitation with the deposition of argillaceous sediments (EF1, Northern Apennines), and/or limestone (EF2, Sicily and Spain) during the humid phase in the precession climate cycle.The stacking pattern and selenite facies associations suggest an overall shallowing-upward trend with a basin-wide hydrologic change starting from the 6th cycle (5.84 Ma), which is marked by the appearance of the branching selenite facies (supercones) in Spain and indicates that the brines became current-dominated. The Sr-isotope stratigraphy suggests that in the Northern Apennines the brines were strongly modified by continental waters (⁸⁷Sr/⁸⁶Sr = 0.708893 to 0.708998), and received direct pulses of Atlantic seawater (⁸⁷Sr/⁸⁶Sr = 0.70900 to 0.709024) only in the upper part of the section. In areas away from the mainland, such as Sicily, the continental input was by far less important.     

Binding of hepatitis C virus envelope protein E2 to CD81 up-regulates matrix metalloproteinase-2 in human hepatic stellate cells

The hepatitis C virus (HCV) envelope E2 glycoprotein is a key molecule regulating the interaction of HCV with cell surface proteins. E2 binds the major extracellular loop of human CD81, a tetraspanin expressed on various cell types including hepatocytes and B lymphocytes. Regardless, information on the biological functions originating from this interaction are largely unknown. Since human hepatic stellate cells (HSC) express high levels of CD81 at the cell surface, we investigated the E2/CD81 interaction in human HSC and the possible effects arising from this interaction. Matrix metalloproteinase-2 (MMP-2; gelatinase A), a major enzyme involved in the degradation of normal hepatic extracellular matrix, was up-regulated following the interaction between E2 and CD81. In particular, by employing zymography and Western blot, we observed that E2 binding to CD81 induces a time-dependent increase in the synthesis and activity of MMP-2. This effect was abolished by preincubating HSC with an anti-CD81 neutralizing antibody. Similar effects were detected in NIH3T3 mouse fibroblasts transfected with human CD81 with identical time course features. In addition, E2/CD81 interaction in human HSC induced the up-regulation of MMP-2 by increasing activator protein-2/DNA binding activity via ERK/MAPK phosphorylation. Finally, suppression of CD81 by RNA interference in human HSC abolished the described effects of E2 on these cells, indicating that CD81 is essential for the activation of the signaling pathway leading to the up-regulation of MMP-2. These results suggest that HSC may represent a potential target for HCV. The interaction of HCV envelope with CD81 on the surface of human HSC induces an increased expression of MMP-2. Increased degradation of the normal hepatic extracellular matrix in areas where HCV is concentrated may favor inflammatory infiltration and further parenchymal damage.     

Identification of horizontally transferred genes in the genus Colletotrichum reveals a steady tempo of bacterial to fungal gene transfer

Background

Horizontal gene transfer (HGT) is the stable transmission of genetic material between organisms by means other than vertical inheritance. HGT has an important role in the evolution of prokaryotes but is relatively rare in eukaryotes. HGT has been shown to contribute to virulence in eukaryotic pathogens. We studied the importance of HGT in plant pathogenic fungi by identifying horizontally transferred genes in the genomes of three members of the genus Colletotrichum.

Results

We identified eleven HGT events from bacteria into members of the genus Colletotrichum or their ancestors. The HGT events include genes involved in amino acid, lipid and sugar metabolism as well as lytic enzymes. Additionally, the putative minimal dates of transference were calculated using a time calibrated phylogenetic tree. This analysis reveals a constant flux of genes from bacteria to fungi throughout the evolution of subphylum Pezizomycotina.

Conclusions

Genes that are typically transferred by HGT are those that are constantly subject to gene duplication and gene loss. The functions of some of these genes suggest roles in niche adaptation and virulence. We found no evidence of a burst of HGT events coinciding with major geological events. In contrast, HGT appears to be a constant, albeit rare phenomenon in the Pezizomycotina, occurring at a steady rate during their evolution.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-16-2) contains supplementary material, which is available to authorized users.