Fine Mapping of the Interaction between C4b-Binding Protein and Outer Membrane Proteins LigA and LigB of Pathogenic Leptospira interrogans.

The complement system consists of more than 40 proteins that participate in the inflammatory response and in pathogen killing. Complement inhibitors are necessary to avoid the excessive consumption and activation of this system on host cells. Leptospirosis is a worldwide zoonosis caused by spirochetes from the genus Leptospira. Pathogenic leptospires are able to escape from complement activation by binding to host complement inhibitors Factor H [FH] and C4b-binding protein (C4BP) while non-pathogenic leptospires are rapidly killed in the presence of fresh serum. In this study, we demonstrate that complement control protein domains (CCP) 7 and 8 of C4BP α-chain interact with the outer membrane proteins LcpA, LigA and LigB from the pathogenic leptospire L. interrogans. The interaction between C4BP and LcpA, LigA and LigB is sensitive to ionic strength and inhibited by heparin. We fine mapped the LigA and LigB domains involved in its binding to C4BP and heparin and found that both interactions are mediated through the bacterial immunoglobulin-like (Big) domains 7 and 8 (LigA7-8 and LigB7-8) of both LigA and LigB and also through LigB9-10. Therefore, C4BP and heparin may share the same binding sites on Lig proteins

Fine Mapping of the Interaction between C4b-Binding Protein and Outer Membrane Proteins LigA and LigB of Pathogenic Leptospira interrogans.

The complement system consists of more than 40 proteins that participate in the inflammatory response and in pathogen killing. Complement inhibitors are necessary to avoid the excessive consumption and activation of this system on host cells. Leptospirosis is a worldwide zoonosis caused by spirochetes from the genus Leptospira. Pathogenic leptospires are able to escape from complement activation by binding to host complement inhibitors Factor H [FH] and C4b-binding protein (C4BP) while non-pathogenic leptospires are rapidly killed in the presence of fresh serum. In this study, we demonstrate that complement control protein domains (CCP) 7 and 8 of C4BP α-chain interact with the outer membrane proteins LcpA, LigA and LigB from the pathogenic leptospire L. interrogans. The interaction between C4BP and LcpA, LigA and LigB is sensitive to ionic strength and inhibited by heparin. We fine mapped the LigA and LigB domains involved in its binding to C4BP and heparin and found that both interactions are mediated through the bacterial immunoglobulin-like (Big) domains 7 and 8 (LigA7-8 and LigB7-8) of both LigA and LigB and also through LigB9-10. Therefore, C4BP and heparin may share the same binding sites on Lig proteins

Chemical Chaperones Curcumin and 4-Phenylbutyric Acid Improve Secretion of Mutant Factor H R127H by Fibroblasts from a Factor H-Deficient Patient

Factor H (FH) is one of the most important regulatory proteins of the alternative pathway of the complement system. Patients with FH deficiency have a higher risk for development of infections and kidney diseases because of the uncontrolled activation and subsequent depletion of the central regulatory component C3 of the complement system. In this study, we investigated the consequences of the Arg(127)His mutation in FH (FHR127H) previously described in an FH-deficient patient, on the secretion of this protein by skin fibroblasts in vitro. We observed that, although the patient cells stimulated with IFN-gamma were able to synthesize FHR127H, the mutant protein was largely retained within the endoplasmic reticulum (ER), whereas normal human fibroblasts stimulated with IFN-gamma secrete FH without retention in the ER. Moreover, the retention of FHR127H provoked enlargement of ER cisterns after treatment with IFN-gamma. A similar ER retention was observed in Cos-7 cells expressing the mutant FHR127H protein. Despite this deficiency in secretion, we show that the FHR127H mutant is capable of functioning as a cofactor in the Factor I-mediated cleavage of C3. We then evaluated whether a treatment could increase the secretion of FH, and observed that the patient's fibroblasts treated with the chemical chaperones 4-phenylbutiric acid or curcumin increased the secretion rate of FH. We propose that these chemical chaperones could be used as alternative therapeutic agents to increase FH plasma levels in FH-deficient patients caused by secretion delay of this regulatory protein. The Journal of Immunology, 2012, 189: 3242-3248.Fundacao de Amparo a Pesquisa do Estado de Sao PauloFundacao de Amparo a Pesquisa do Estado de Sao PauloConselho Nacional de Pesquisa e Desenvolvimento Cientifico, BrazilConselho Nacional de Pesquisa e Desenvolvimento Cientifico, Brazi

Evaluación de un sistema de centrifugación para el secado de lodos generados en el tratamiento de aguas residuales en la curtiembre El Escorpión del municipio de Villapinzón, Cundinamarca

The tannery industry generates a high load of pollutant represented by liquid and solid waste, among solid waste the final disposal of sludge from wastewater treatment represents a serious inconvenience in terms of handling, processing time and final disposal cost. A centrifugation system with filter cloth was evaluated in order to analyze an alternative that allows to reduce the time of treatment, cost and seek to obtain environmental benefits for the tanner sector. The filtering materials were 5 types of fabrics (cambre, jungle mother, jean, military and gladiator) and it was determined that the resistance to filtration offered by each material is not significant, on the other hand, the sludge product of the wastewater treatment of hair offers high resistance to solid / water separation (r = 7.0179E + 13 s²/kg) and therefore a low filtration range (Y = 0.000413 kg/m²*h), which makes a centrifugation system for this type of mud requires of a considerable area and high energy consumption.    La industria de curtiembres genera una alta carga de contaminante representada por residuos líquidos y sólidos, entre los residuos sólidos la disposición final de los lodos del tratamiento de aguas residuales representa un serio inconveniente en términos de manejo, tiempo de procesamiento y costo de disposición final. Se evaluó un sistema de centrifugación con tela filtrante con el objeto de analizar una alternativa que permita reducir el tiempo de tratamiento, costo y buscar obtener beneficios ambientales para el sector curtidor. Los materiales filtrantes fueron 5 tipos de telas (cambre, madre selva, jean, militar y gladiador) y se determinó que la resistencia a la filtración que ofrece cada material no es significativa, por otra parte, el lodo producto del tratamiento de agua residuales de pelambre ofrece alta resistencia a la separación sólido/agua (r= 7,0179E+13 s²/kg) y por lo tanto un bajo alcance de filtración (Y= 0,000413 kg/m²*h), hecho que hace que un sistema de centrifugación para este tipo de lodo requiera de una considerable área y alto consumo energético. &nbsp

Interaction of leptospira elongation factor tu with plasminogen and complement factor h: a metabolic leptospiral protein with moonlighting activities

The elongation factor Tu (EF-Tu), an abundant bacterial protein involved in protein synthesis, has been shown to display moonlighting activities. Known to perform more than one function at different times or in different places, it is found in several subcellular locations in a single organism, and may serve as a virulence factor in a range of important human pathogens. Here we demonstrate that Leptospira EF-Tu is surface-exposed and performs additional roles as a cell-surface receptor for host plasma proteins. It binds plasminogen in a dose-dependent manner, and lysine residues are critical for this interaction. Bound plasminogen is converted to active plasmin, which, in turn, is able to cleave the natural substrates C3b and fibrinogen. Leptospira EF-Tu also acquires the complement regulator Factor H (FH). FH bound to immobilized EF-Tu displays cofactor activity, mediating C3b degradation by Factor I (FI). In this manner, EF-Tu may contribute to leptospiral tissue invasion and complement inactivation. To our knowledge, this is the first description of a leptospiral protein exhibiting moonlighting activitiesFAPESP, 00/11624-

The major autoantibody epitope on factor H in atypical hemolytic uremic syndrome is structurally different from its homologous site in factor H-related protein 1, supporting a novel model for induction of autoimmunity in this disease

Atypical hemolytic uremic syndrome (aHUS) is characterized by complement attack against host cells due to mutations in complement proteins or autoantibodies against complement factor H (CFH). It is unknown why nearly all patients with autoimmune aHUS lack CFHR1 (CFH-related protein-1). These patients have autoantibodies against CFH domains 19 and 20 (CFH19-20), which are nearly identical to CFHR1 domains 4 and 5 (CFHR14-5). Here, binding site mapping of autoantibodies from 17 patients using mutant CFH19-20 constructs revealed an autoantibody epitope cluster within a loop on domain 20, next to the two buried residues that are different in CFH19-20 and CFHR14-5. The crystal structure of CFHR14-5 revealed a difference in conformation of the autoantigenic loop in the C-terminal domains of CFH and CFHR1, explaining the variation in binding of autoantibodies from some aHUS patients to CFH19-20 and CFHR14-5. The autoantigenic loop on CFH seems to be generally flexible, as its conformation in previously published structures of CFH19-20 bound to the microbial protein OspE and a sialic acid glycan is somewhat altered. Cumulatively, our data suggest that association of CFHR1 deficiency with autoimmune aHUS could be due to the structural difference between CFHR1 and the autoantigenic CFH epitope, suggesting a novel explanation for CFHR1 deficiency in the pathogenesis of autoimmune aHUS

Factor H family proteins in complement evasion of microorganisms

Human-pathogenic microbes possess various means to avoid destruction by our immune system. These include interactions with the host complement system that may facilitate pathogen entry into cells and tissues, expression of molecules that defuse the effector complement components and complexes, and acquisition of host complement inhibitors to downregulate complement activity on the surface of the pathogen. A growing number of pathogenic microorganisms have acquired the ability to bind the complement inhibitor factor H (FH) from body fluids and thus hijack its host protecting function. In addition to FH, binding of FH-related (FHR) proteins was also demonstrated for several microbes. Initial studies assumed that these proteins are complement inhibitors similar to FH. However, recent evidence suggests that FHR proteins may rather enhance complement activation both directly and also by competing with the inhibitor FH for binding to certain ligands and surfaces. This mini review focuses on the role of the main alternative pathway regulator FH in host-pathogen interactions, as well as on the emerging role of the FHR proteins as enhancers of complement activation

Achieving sustainable development in rural areas in Colombia: Future scenarios for biodiversity conservation under land use change

Agricultural expansion is a complex land use change phenomenon with deep environmental and socio-economic consequences, especially across tropical countries where most of this expansion is occurring. Here we use scenario and network analysis combined with sustainability assessment to understand the drivers of landscape change and their effects on sustainable development in Colombia’s rural areas, using the Central Magdalena region as a case study, and ultimately informing strategies to reconcile agricultural expansion with biodiversity conservation and rural development. Using this approach we investigated three environmental and agricultural policy scenarios: the Business as Usual scenario, enforcing a stronger regulatory framework, and adopting incentives. Our analysis show that the Business as Usual scenario is not supported by stakeholders and negatively affects most sustainability objectives with the predominant agricultural sectors in the region (cattle ranching and oil palm) not improving social inequality, and threatening biodiversity, natural resources, and food security. Both alternative scenarios improve overall sustainability, including biodiversity. Therefore to reconcile agricultural expansion, biodiversity and sustainable development, it is important to adopt a stronger regulatory and enforcement framework at different administrative levels, as well as incentive schemes focusing on small holders. Our study also shows that history cannot be ignored when thinking about the future and sustainability especially in areas with legacies of strong inequalities caused by armed conflict. Finally, we suggest that combining scenario analysis, network analysis, and sustainability assessment is a useful methodology for studying land use changes holistically, exploring complex systems at different scales, and informing locally-relevant strategies and recommendations, ultimately enabling science to be proactive

Low emission development strategies in agriculture. An agriculture, forestry, and other land uses (AFOLU) perspective

As countries experience economic growth and choose among available development pathways, they are in a favorable position to adopt natural resource use technologies and production practices that favor efficient use of inputs, healthy soils, and ecosystems. Current emphasis on increasing resilience to climate change and reducing agricultural greenhouse gasses (GHG) emissions strengthens the support for sustainable agricultural production. In fact, reducing losses in soil fertility, reclaiming degraded lands, and promoting synergistic interaction between crop production and forests are generally seen as good climate change policies. In order for decision-makers to develop long-term policies that address these issues, they must have tools at their disposal that evaluate trade-offs, opportunities, and repercussions of the options considered. In this paper, the authors combine and reconcile the output of three models widely accessible to the public to analyze the impacts of policies that target emission reduction in the agricultural sector. We present an application to Colombia which reveals the importance of considering the full scope of interactions among the various land uses. Results indicate that investments in increasing the efficiency and productivity of the livestock sector and reducing land allocated to pasture are preferable to policies that target deforestation alone or target a reduction of emissions in crop production. Investments in livestock productivity and land-carrying capacity would reduce deforestation and provide sufficient gains in carbon stock to offset greater emissions from increased crop production while generating higher revenues