161 research outputs found
Land subsidence, Ground Fissures and Buried Faults: InSAR Monitoring of Ciudad Guzmán (Jalisco, Mexico)
We study land subsidence processes and the associated ground fissuring, affecting
an active graben filled by thick unconsolidated deposits by means of InSAR techniques and
fieldwork. On 21 September 2012, Ciudad Guzmán (Jalisco, Mexico) was struck by ground
fissures of about 1.5 km of length, causing the deformation of the roads and the propagation
of fissures in adjacent buildings. The field survey showed that fissures alignment is
coincident with the escarpments produced on 19 September 1985, when a strong earthquake
with magnitude 8.1 struck central Mexico. In order to detect and map the spatio-temporal
features of the processes that led to the 2012 ground fissures, we applied InSAR multitemporal
techniques to process ENVISAT-ASAR and RADARSAT-2 satellite SAR images
acquired between 2003 and 2012. We detect up to 20 mm/year of subsidence of the
northwestern part of Ciudad Guzmán. These incremental movements are consistent with the ground fissures observed in 2012. Based on interferometric results, field data and 2D
numerical model, we suggest that ground deformations and fissuring are due to the presence
of areal subsidence correlated with variable sediment thickness and differential compaction,
partly driven by the exploitation of the aquifers and controlled by the distribution and
position of buried faults
Immune adaptor ADAP in T cells regulates HIV-1 transcription and cell-cell viral spread via different co-receptors
Background: Immune cell adaptor protein ADAP (adhesion and degranulation-promoting adaptor protein) mediates aspects of T-cell adhesion and proliferation. Despite this, a connection between ADAP and infection by the HIV-1 (human immunodeficiency virus-1) has not been explored. Results: In this paper, we show for the first time that ADAP and its binding to SLP-76 (SH2 domain-containing leukocyte protein of 76 kDa) regulate HIV-1 infection via two distinct mechanisms and co-receptors. siRNA down-regulation of ADAP, or expression of a mutant that is defective in associating to its binding partner SLP-76 (termed M12), inhibited the propagation of HIV-1 in T-cell lines and primary human T-cells. In one step, ADAP and its binding to SLP-76 were needed for the activation of NF-κB and its transcription of the HIV-1 long terminal repeat (LTR) in cooperation with ligation of co-receptor CD28, but not LFA-1. In a second step, the ADAP-SLP-76 module cooperated with LFA-1 to regulate conjugate formation between T-cells and dendritic cells or other T-cells as well as the development of the virological synapse (VS) and viral spread between immune cells. Conclusions: These findings indicate that ADAP regulates two steps of HIV-1 infection cooperatively with two distinct receptors, and as such, serves as a new potential target in the blockade of HIV-1 infection
Preliminary data on the structure and potential of the Tocomar geothermal field (Puna plateau, Argentina).
AbstractThis study presents new stratigraphic, structural and hydrogeological data on the Tocomar geothermal volcanic area (Puna plateau, Central Andes, NW Argentina), together with preliminary geochemical and magnetotelluric data.The main geothermal reservoir is located within the fractured Pre-Palaeozoic–Ordovician units. The reservoir is recharged by meteoric waters. Geothermal fluids upwell where main regional structures intersect secondary structures associated with the development of the Tocomar basin. Preliminary data indicate a reservoir temperature of ∼ 200° C and a local geothermal gradient of ∼ 130° C/km associated with the Quaternary volcanic activity in the Tocomar area
Geology of La Reforma caldera complex, Baja California, Mexico
A new geological map at 1:50,000 scale of La Reforma Caldera Complex has been produced applying modern survey methodologies to volcanic areas. This map aims to represent a reliable and objective tool to understand the geological evolution of the region. La Reforma Caldera Complex is a Pleistocene nested caldera located in the central part of the Baja California peninsula, Mexico. The twelve formations defined within the Quaternary volcanic record were grouped into three phases (pre-caldera, caldera, and post-caldera). The pre-caldera phase (>1.35 Ma) is characterized by scattered eruptions, mostly occurred in submarine environment. The caldera phase (1.35–0.96 Ma) groups several distinct explosive and effusive eruptions that formed the present-day caldera depression. The post caldera phase includes scattered effusive eruptions (ended at 0.28 Ma) and resurgence, characterized by several hundred meters of uplift of the central block within the caldera depression
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Implications of O-glycan modifications in the hinge region of a plant-produced SARS-CoV-2-IgA antibody on functionality.
Introduction: Prolyl-4-hydroxylases (P4H) catalyse the irreversible conversion of proline to hydroxyproline, constituting a common posttranslational modification of proteins found in humans, plants, and microbes. Hydroxyproline residues can be further modified in plants to yield glycoproteins containing characteristic O-glycans. It is currently unknown how these plant endogenous modifications impact protein functionality and they cause considerable concerns for the recombinant production of therapeutic proteins in plants. In this study, we carried out host engineering to generate a therapeutic glycoprotein largely devoid of plant-endogenous O-glycans for functional characterization. Methods: Genome editing was used to inactivate two genes coding for enzymes of the P4H10 subfamily in the widely used expression host Nicotiana benthamiana. Using glycoengineering in plants and expression in human HEK293 cells we generated four variants of a potent, SARS-CoV-2 neutralizing antibody, COVA2-15 IgA1. The variants that differed in the number of modified proline residues and O-glycan compositions of their hinge region were assessed regarding their physicochemical properties and functionality. Results: We found that plant endogenous O-glycan formation was strongly reduced on IgA1 when transiently expressed in the P4H10 double mutant N. benthamiana plant line. The IgA1 glycoforms displayed differences in proteolytic stability and minor differences in receptor binding thus highlighting the importance of O-glycosylation in the hinge region of human IgA1. Discussion: This work reports the successful protein O-glycan engineering of an important plant host for recombinant protein expression. While the complete removal of endogenous hydroxyproline residues from the hinge region of plant-produced IgA1 is yet to be achieved, our engineered line is suitable for structure-function studies of O-glycosylated recombinant glycoproteins produced in plants
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The QuantuMDx Q-POC SARS-CoV-2 RT-PCR assay for rapid detection of COVID-19 at point-of-care: preliminary evaluation of a novel technology
Abstract: Accurate and rapid point-of-care (PoC) diagnostics are critical to the control of the COVID-19 pandemic. The current standard for accurate diagnosis of SARS-CoV-2 is laboratory-based reverse transcription polymerase chain reaction (RT-PCR) assays. Here, a preliminary prospective performance evaluation of the QuantuMDx Q-POC SARS-CoV-2 RT-PCR assay is reported. Between November 2020 and March 2021, 49 longitudinal combined nose/throat (NT) swabs from 29 individuals hospitalised with RT-PCR confirmed COVID-19 were obtained at St George’s Hospital, London. In addition, 101 mid-nasal (MN) swabs were obtained from healthy volunteers in June 2021. These samples were used to evaluate the Q-POC SARS-CoV-2 RT-PCR assay. The primary analysis was to compare the sensitivity and specificity of the Q-POC test against a reference laboratory-based RT-PCR assay. The overall sensitivity of the Q-POC test compared with the reference test was 96.88% (83.78– 99.92% CI) for a cycle threshold (Ct) cut-off value for the reference test of 35 and 80.00% (64.35–90.95% CI) without altering the reference test’s Ct cut-off value of 40. The Q-POC test is a sensitive, specific and rapid PoC test for SARS-CoV-2 at a reference Ct cut-off value of 35. The Q-POC test provides an accurate option for RT-PCR at PoC without the need for sample pre-processing and laboratory handling, enabling rapid diagnosis and clinical triage in acute care and other settings
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