Ion-Abrasion Scanning Electron Microscopy Reveals Surface-Connected Tubular Conduits in HIV-Infected Macrophages

HIV-1-containing internal compartments are readily detected in images of thin sections from infected cells using conventional transmission electron microscopy, but the origin, connectivity, and 3D distribution of these compartments has remained controversial. Here, we report the 3D distribution of viruses in HIV-1-infected primary human macrophages using cryo-electron tomography and ion-abrasion scanning electron microscopy (IA-SEM), a recently developed approach for nanoscale 3D imaging of whole cells. Using IA-SEM, we show the presence of an extensive network of HIV-1-containing tubular compartments in infected macrophages, with diameters of ∼150–200 nm, and lengths of up to ∼5 µm that extend to the cell surface from vesicular compartments that contain assembling HIV-1 virions. These types of surface-connected tubular compartments are not observed in T cells infected with the 29/31 KE Gag-matrix mutant where the virus is targeted to multi-vesicular bodies and released into the extracellular medium. IA-SEM imaging also allows visualization of large sheet-like structures that extend outward from the surfaces of macrophages, which may bend and fold back to allow continual creation of viral compartments and virion-lined channels. This potential mechanism for efficient virus trafficking between the cell surface and interior may represent a subversion of pre-existing vesicular machinery for antigen capture, processing, sequestration, and presentation

AAV-mediated human PEDF inhibits tumor growth and metastasis in murine colorectal peritoneal carcinomatosis model

<p>Abstract</p> <p>Background</p> <p>Angiogenesis plays an important role in tumor growth and metastasis, therefore antiangiogenic therapy was widely investigated as a promising approach for cancer therapy. Recently, pigment epithelium-derived factor (PEDF) has been shown to be the most potent inhibitor of angiogenesis. Adeno-associated virus (AAV) vectors have been intensively studied due to their wide tropisms, nonpathogenicity, and long-term transgene expression <it>in vivo</it>. The objective of this work was to evaluate the ability of AAV-mediated human PEDF (hPEDF) as a potent tumor suppressor and a potential candidate for cancer gene therapy.</p> <p>Methods</p> <p>Recombinant AAV₂encoding hPEDF (rAAV₂-hPEDF) was constructed and produced, and then was assigned for <it>in vitro </it>and <it>in vivo </it>experiments. Conditioned medium from cells infected with rAAV₂-hPEDF was used for cell proliferation and tube formation tests of human umbilical vein endothelial cells (HUVECs). Subsequently, colorectal peritoneal carcinomatosis (CRPC) mouse model was established and treated with rAAV₂-hPEDF. Therapeutic efficacy of rAAV₂-hPEDF were investigated, including tumor growth and metastasis, survival time, microvessel density (MVD) and apoptosis index of tumor tissues, and hPEDF levels in serum and ascites.</p> <p>Results</p> <p>rAAV₂-hPEDF was successfully constructed, and transmission electron microscope (TEM) showed that rAAV₂-hPEDF particles were non-enveloped icosahedral shape with a diameter of approximately 20 nm. rAAV₂-hPEDF-infected cells expressed hPEDF protein, and the conditioned medium from infected cells inhibited proliferation and tube-formation of HUVECs <it>in vitro</it>. Furthermore, in CRPC mouse model, rAAV₂-hPEDF significantly suppressed tumor growth and metastasis, and prolonged survival time of treated mice. Immunofluorescence studies indicated that rAAV₂-hPEDF could inhibit angiogenesis and induce apoptosis in tumor tissues. Besides, hPEDF levels in serum and ascites of rAAV₂-hPEDF-treated mice were significant higher than those in rAAV₂-null or normal saline (NS) groups.</p> <p>Conclusions</p> <p>Thus, our results suggest that rAAV₂-hPEDF may be a potential candidate as an antiangiogenic therapy agent.</p

Triggering of major eruptions recorded by actively forming cumulates

Major overturn within a magma chamber can bring together felsic and mafic magmas, prompting de-volatilisation and acting as the driver for Plinian eruptions. Until now identification of mixing has been limited to analysis of lavas or individual crystals ejected during eruptions. We have recovered partially developed cumulate material (‘live’ cumulate mush) from pyroclastic deposits of major eruptions on Tenerife. These samples represent “frozen” clumps of diverse crystalline deposits from all levels in the developing reservoir, which are permeated with the final magma immediately before eruptions. Such events therefore record the complete disintegration of the magma chamber, leading to caldera collapse. Chemical variation across developing cumulus crystals records changes in melt composition. Apart from fluctuations reflecting periodic influxes of mafic melt, crystal edges consistently record the presence of more felsic magmas. The prevalence of this felsic liquid implies it was able to infiltrate the entire cumulate pile immediately before each eruption

Growth and water relations of field-grown Valencia orange trees under long-term partial rootzone drying

Climate, soil water potential (SWP), leaf relative water content (RWC), stem water potential (WPstem), stomatal conductance (gs), trunk, shoot and fruit growth of 'Valencia' orange trees were monitored during five consecutive seasons (2007â2012) to study water status and growth responses to irrigation placement or volume. 48 adult trees were exposed to conventional irrigation (CI, 100% of crop evapotranspiration on both sides of the rootzone), partial rootzone drying (PRD, 50% of CI water only on one alternated side of the rootzone) and continuous deficit irrigation (DI, 50% of CI water on both sides of the rootzone). Reducing irrigation volumes by 55% (DI) over CI increased leaf water deficit by 27% and reduced 'Valencia' fruit growth by 15% but not shoot or trunk growth. Similar water savings by PRD did not induce significant growth reductions. Differences in fruit growth rates determined 17% yield reduction in DI but not PRD trees. If we consider integrals of data across each season, PRD induced milder soil and leaf water deficit than DI but similar stomatal conductance. Tree daily water consumption (Etree) estimated from daily leaf transpiration was significantly lower in PRD and DI than in CI. Fruit growth efficiency (growth rate per unit Etree) was similar in all irrigation treatments, while shoot growth efficiency was higher in PRD than in CI. In PRD, an increased shoot growth efficiency rather than fruit growth efficiency is most likely due to water and assimilates being diverted from fruit to shoot growth under high VPD conditions. Although these results show good evidence of an irrigation placement effect inducing an advantage of the PRD strategy in 'Valencia' orange in terms of milder soil and leaf water deficit and more sustainable fruit growth compared to DI, PRD did not induce any significant advantage in terms of final yield over a simple reduction of irrigation volumes

Investigação do Modo Sul em dados de precipitação no período de 1982 a 2006 no estado do Rio Grande do Sul Research of "modo sul" on rainfall data during the period from 1982 to 2006 in Rio Grande do Sul state

Este trabalho apresenta o estudo de um modo de variabilidade que influencia a precipitação no Sul do Brasil e é chamado Modo Sul de precipitação. Será mostrado que a ocorrência de máximos (e mínimos) do Modo Sul de precipitação pode estar relacionada à ocorrência de eventos extremos no Rio Grande do Sul, como vendavais, enchentes, granizo e estiagens Utilizando a análise de componentes principais em dados de precipitação diária filtrados na banda 10-50 dias, são encontrados campos espaciais e temporais que representam a máxima variância de determinadas variabilidades, e neles são detectados Modos de Variabilidade de precipitação. Desta maneira, foi possível determinar este modo de variabilidade, que aparece bem configurado na região do Rio Grande do Sul. A série de componentes principais foi usada para a escolha desses eventos. O Modo Sul foi calculado para o período de 01/03/1982 à 31/05/2006. Foi possível identificar que os eventos extremos chuvosos ocorreram em maior número do que os eventos extremos secos. Na análise decadal verificou-se um aumento no número de eventos, quando comparada às décadas de 80, 90 e 2000. Vale ressaltar que o número de eventos da década de 2000 em relação à década de 80 (proporcionalmente) foi o mais expressivo.<br>This work presents a study of a rainfall variability mode that acts in southern Brazil and is called "Modo Sul" of precipitation. It was tried to show that the occurrences of maximum (and minimum) of the "Modo Sul" of precipitation are related to the occurrence of extreme events in Rio Grande do Sul, as windstorm, flood, hail and drought. Using principal component analysis of daily filtered precipitation data for the 10-50 day band we found spatial pattern and temporal series that represent the maximum variance of certain variabilities, which are the modes of precipitation variability. Thus, it was possible to determine the mode of variability that appears well established in Rio Grande do Sul. The principal component series was used to select the extreme events. The "Modo Sul" was calculated for the period from 01/03/1982 to 31/05/2006. It was possible to realize that the extreme rainy events were more frequent than extreme dry events. In a decadal analysis an increase in the number of events was found when comparing the 80s, 90s and 2000. It is noteworthy that the number of events of 2000s compared with the 80s was proportionally the most expressive