Heterologous expression of the filarial nematode alt gene products reveals their potential to inhibit immune function

BACKGROUND: Parasites exploit sophisticated strategies to evade host immunity that require both adaptation of existing genes and evolution of new gene families. We have addressed this question by testing the immunological function of novel genes from helminth parasites, in which conventional transgenesis is not yet possible. We investigated two such novel genes from Brugia malayi termed abundant larval transcript (alt), expression of which reaches ~5% of total transcript at the time parasites enter the human host. RESULTS: To test the hypothesis that ALT proteins modulate host immunity, we adopted an alternative transfection strategy to express these products in the protozoan parasite Leishmania mexicana. We then followed the course of infection in vitro in macrophages and in vivo in mice. Expression of ALT proteins, but not a truncated mutant, conferred greater infectivity of macrophages in vitro, reaching 3-fold higher parasite densities. alt-transfected parasites also caused accelerated disease in vivo, and fewer mice were able to clear infection of organisms expressing ALT. alt-transfected parasites were more resistant to IFN-γ-induced killing by macrophages. Expression profiling of macrophages infected with transgenic L. mexicana revealed consistently higher levels of GATA-3 and SOCS-1 transcripts, both associated with the Th2-type response observed in in vivo filarial infection. CONCLUSION: Leishmania transfection is a tractable and informative approach to determining immunological functions of single genes from heterologous organisms. In the case of the filarial ALT proteins, our data suggest that they may participate in the Th2 bias observed in the response to parasite infection by modulating cytokine-induced signalling within immune system cells

Gene copy number variation throughout the Plasmodium falciparum genome

BACKGROUND: Gene copy number variation (CNV) is responsible for several important phenotypes of the malaria parasite Plasmodium falciparum, including drug resistance, loss of infected erythrocyte cytoadherence and alteration of receptor usage for erythrocyte invasion. Despite the known effects of CNV, little is known about its extent throughout the genome. RESULTS: We performed a whole-genome survey of CNV genes in P. falciparum using comparative genome hybridisation of a diverse set of 16 laboratory culture-adapted isolates to a custom designed high density Affymetrix GeneChip array. Overall, 186 genes showed hybridisation signals consistent with deletion or amplification in one or more isolate. There is a strong association of CNV with gene length, genomic location, and low orthology to genes in other Plasmodium species. Sub-telomeric regions of all chromosomes are strongly associated with CNV genes independent from members of previously described multigene families. However, approximately 40% of CNV genes were located in more central regions of the chromosomes. Among the previously undescribed CNV genes, several that are of potential phenotypic relevance are identified. CONCLUSION: CNV represents a major form of genetic variation within the P. falciparum genome; the distribution of gene features indicates the involvement of highly non-random mutational and selective processes. Additional studies should be directed at examining CNV in natural parasite populations to extend conclusions to clinical settings

Expression and immune recognition of Brugia malayi VAL-1, a homologue of vespid venom allergens and Ancylostoma secreted proteins

Several important nematode parasites have been found to express members of a gene family variously termed as venom allergen antigen homologue (vah) or Ancylostoma secreted protein (asp). In some cases these products are secreted by infective larval stages and have been suggested to be effective vaccine immunogens. We isolated the corresponding gene from the human filarial nematode, Brugia malayi, by first searching the expressed sequence tag (EST) dataset generated by the Filarial Genome Project and then using gene-specific nondegenerate primers matching the selected gene for PCR, from B. malayi cDNA libraries. We report here the full-length gene sequence, which we have designated as Bm-val-1, for vah/asp-like. The corresponding protein (Bm-VAL-1) contains 232 amino acids in a single homology unit, unlike products from some other species in which there is a tandem repeat. A putative signal sequence is present at the 5' end and there are two potential N-glycosylation sites. Murine antibodies to recombinant Bm-VAL-1 react with a 28 kDa protein in L3 extracts and recombinant Bm-VAL-1 is recognised by murine T cells primed with soluble L3 proteins. Of 82 ESTs corresponding to Bm-val-1, 72 are recorded from the infective larval (L3) stage. However, PCR on the first-strand cDNA libraries from later mammalian stages revealed some expression at most subsequent time points. Over 95% (20/21) of microfilaraemic human filariasis patients are seropositive for antibodies to Bm-VAL-1, with particularly high levels of IgG3 and IgG4 isotypes. The IgG4 subclass may indicate stimulation by adult and/or microfilarial-derived immunogens. The association of Bm-VAL-1 with the infective stage and its recognition by humans exposed to filariasis suggests that further evaluation of this antigen as a vaccine candidate should be performed. © 2001 Published by Elsevier Science B.V

Invited review Immune evasion genes from ®larial nematodes

Abstract Helminth parasites have large genomes (~10 8 bp) which are likely to encode a spectrum of products able to block or divert the host immune response. We have employed three parallel approaches to identify the ®rst generation of`immune evasion genes' from parasites such as the ®larial nematode Brugia malayi. The ®rst strategy is a conventional route to characterise prominent surface or secreted antigens. In this way we have identi®ed a 15-kDa protein, which is located on the surface of both L3 and adult B. malayi, and secreted by these parasites in vitro, as a member of the cystatin (cysteine protease inhibitor) family. This product, Bm-CPI-2, blocks conventional cysteine proteases such as papain, but also the aspariginyl endopeptidase involved in the Class II antigen processing pathway in human B cells. In parallel, we identi®ed the major T cell-stimulating antigen from the micro®larial stage as a serpin (serine protease inhibitor), Bm-SPN-2. Micro®lariae secrete this product which blocks two key proteases of the neutrophil, a key mediator of in¯ammation and innate immunity. The second route involves a priori hypotheses that helminth parasites encode homologues of mammalian cytokines such as TGF-b which are members of broad, ancient metazoan gene families. We have identi®ed two TGF-b homologues in B. malayi, and shown that one form (Bm-TGH-2) is both secreted by adult parasites in vitro and able to bind to host TGF-b receptors. Likewise, B. malayi expresses homologues of mammalian MIF, which are remarkably similar in both structure and function to the host protein, even though amino acid identity is only 28%. Finally, we deployed a third method of selecting critical genes, using an expression-based criterion to select abundant mRNAs taken from key points in parasite life histories. By this means, we have shown that the major transcript present in mosquito-borne infective larvae, Bm-ALT, is a credible vaccine candidate for use against lymphatic ®lariasis, while a second abundantly-expressed gene, Bm-VAL-1, is similar to a likely vaccine antigen being developed against hookworm parasites.

Translin and Trax differentially regulate telomere-associated transcript homeostasis

Translin and Trax proteins are highly conserved nucleic acid binding proteins that have been implicated in RNA regulation in a range of biological processes including tRNA processing, RNA interference, microRNA degradation during oncogenesis, spermatogenesis and neuronal regulation. Here, we explore the function of this paralogue pair of proteins in the fission yeast. Using transcript analysis we demonstrate a reciprocal mechanism for control of telomere-associated transcripts. Mutation of tfx1(+) (Trax) elevates transcript levels from silenced sub-telomeric regions of the genome, but not other silenced regions, such as the peri-centromeric heterochromatin. In the case of some sub-telomeric transcripts, but not all, this elevation is dependent on the Trax paralogue, Tsn1 (Translin). In a reciprocal fashion, Tsn1 (Translin) serves to repress levels of transcripts (TERRAs) from the telomeric repeats, whereas Tfx1 serves to maintain these elevated levels. This reveals a novel mechanism for the regulation of telomeric transcripts. We extend this to demonstrate that human Translin and Trax also control telomere-associated transcript levels in human cells in a telomere-specific fashion

Translin facilitates RNA polymerase II dissociation and suppresses genome instability during RNase H2- and Dicer-deficiency

The conserved nucleic acid binding protein Translin contributes to numerous facets of mammalian biology and genetic diseases. It was first identified as a binder of cancer-associated chromosomal translocation breakpoint junctions leading to the suggestion that it was involved in genetic recombination. With a paralogous partner protein, Trax, Translin has subsequently been found to form a hetero-octomeric RNase complex that drives some of its functions, including passenger strand removal in RNA interference (RNAi). The Translin-Trax complex also degrades the precursors to tumour suppressing microRNAs in cancers deficient for the RNase III Dicer. This oncogenic activity has resulted in the Translin-Trax complex being explored as a therapeutic target. Additionally, Translin and Trax have been implicated in a wider range of biological functions ranging from sleep regulation to telomere transcript control. Here we reveal a Trax- and RNAi-independent function for Translin in dissociating RNA polymerase II from its genomic template, with loss of Translin function resulting in increased transcription-associated recombination and elevated genome instability. This provides genetic insight into the longstanding question of how Translin might influence chromosomal rearrangements in human genetic diseases and provides important functional understanding of an oncological therapeutic target

La Imagen y la Narrativa como Herramientas para el Abordaje Psicosocial en Escenarios de Violencia. Departamentos de Huila y Caquetá

No aplicaEl desarrollo del trabajo se enfoca en la construcción de un análisis de la violencia en el caso de Luz, la cual fue la temática escogida grupalmente; por lo tanto, es poder introducirse en las situaciones que emergen del relato y que son expresados a través de la narrativa que nutre la experiencia de los futuros psicólogos en trabajos de intervención y conjuntamente se hace una visibilización de la capacidad de resiliencia de una mujer empoderada que lucha por su legado desde la subjetividad dejando atrás los recuerdos de la guerra para empezar a reconstruir su historia haciendo eco en la sociedad y la misma conozca las realidades de la violencia en Colombia. Asimismo, el aporte y conocimientos producto del trabajo sobre el caso analizado, se avanza en la construcción de una serie de preguntas circulares, reflexivas y estratégicas basadas en el caso escogido y que aportan una serie de elementos con el fin de poder tener un acercamiento psicosocial y moral con el sujeto; además, justificarlas desde el campo psicosocial para tener una comprensión clara de la conducta social de la víctima. De la misma manera; se comparte el informe analítico del paso anterior en la compilación de este parte y que se describe de una forma directa y clara para exista un entendimiento que genere una reflexión en las victimas; conjuntamente, la misma contribuya a tener una perspectiva de las situaciones vividas a través de las imágenes de la mano con la narrativa para aplicarla como estrategia psicosocial.The development of the work focuses on the construction of an analysis of violence in the case of Luz, which was the theme chosen as a group; therefore, it is to be able to enter the situations that emerge from the story and that are expressed through the narrative that nourishes the experience of future psychologists in intervention work and jointly makes visible the resilience capacity of an empowered woman who fights for his legacy from subjectivity, leaving behind the memories of the war to begin to rebuild his history echoing in society and it knows the realities of violence in Colombia. Likewise, the contribution and knowledge product of the work on the analyzed case, progress is being made in the construction of a series of circular, reflective and strategic questions based on the chosen case and that provide a series of elements in order to be able to have a psychosocial approach. And moral with the subject; in addition, justify them from the psychosocial field to have a clear understanding of the social behavior of the victim. In the same way; The analytical report from the previous step in the compilation of this part is shared and that is described in a direct and clear way so that there is an understanding that generates reflection in the victims; jointly, it contributes to have a perspective of the situations experienced through the images hand in hand with the narrative to apply it as a psychosocial strategy

Panorama sanitario del cultivo de la soja en el noroeste argentino durante la campaña 2020/2021

El estrés biótico originado por diversos organismos nocivos constituye uno de los principales factores limitantes de la producción de un cultivo. Es por ello que el principal objetivo de la sección Fitopatología de la Estación Experimental Agroindustrial Obispo Colombres (EEAOC) es investigar las enfermedades más importantes que afectan a los principales cultivos en Tucumán y otras provincias del noroeste argentino (NOA). En este sentido, personal de esta sección realiza anualmente la prospección de enfermedades en los cultivos de mayor importancia de la región, entre ellos la soja[Glycine max (L.) Merrill].En este trabajo se presentan los resultados de las evaluaciones del estado sanitario de los cultivosde soja en la región NOA durante la campaña 2020/2021.Fil: Claps, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Bleckwedel, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Reznikov, Sebastian. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (P); ArgentinaFil: Escobar, Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (P); ArgentinaFil: Aguaysol, Natalia Catalina. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (P); ArgentinaFil: Scalora, Franco. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (P); ArgentinaFil: Lopez, Miguel Angel. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (P); ArgentinaFil: Gomez Fuentes, Carolina Maria. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (P); ArgentinaFil: Lopez Ruiz, Emmina de Lourdes. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (P); ArgentinaFil: Gonzalez, Fernando. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (P); ArgentinaFil: González, Victoria. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (P); ArgentinaFil: Ploper, Leonardo Daniel. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (P); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentin

Continued Decline of Malaria in The Gambia with Implications for Elimination

BACKGROUND: A substantial decline in malaria was reported to have occurred over several years until 2007 in the western part of The Gambia, encouraging consideration of future elimination in this previously highly endemic region. Scale up of interventions has since increased with support from the Global Fund and other donors. METHODOLOGY/PRINCIPAL FINDINGS: We continued to examine laboratory records at four health facilities previously studied and investigated six additional facilities for a 7 year period, adding data from 243,707 slide examinations, to determine trends throughout the country until the end of 2009. We actively detected infections in a community cohort of 800 children living in rural villages throughout the 2008 malaria season, and assayed serological changes in another rural population between 2006 and 2009. Proportions of malaria positive slides declined significantly at all of the 10 health facilities between 2003 (annual mean across all sites, 38.7%) and 2009 (annual mean, 7.9%). Statistical modelling of trends confirmed significant seasonality and decline over time at each facility. Slide positivity was lowest in 2009 at all sites, except two where lowest levels were observed in 2006. Mapping households of cases presenting at the latter sites in 2007-2009 indicated that these were not restricted to a few residual foci. Only 2.8% (22/800) of a rural cohort of children had a malaria episode in the 2008 season, and there was substantial serological decline between 2006 and 2009 in a separate rural area. CONCLUSIONS: Malaria has continued to decline in The Gambia, as indicated by a downward trend in slide positivity at health facilities, and unprecedented low incidence and seroprevalence in community surveys. We recommend intensification of control interventions for several years to further reduce incidence, prior to considering an elimination programme

Immuno-epidemiology of human Schistosoma haematobium infection: preferential IgG3 antibody responsiveness to a recombinant antigen dependent on age and parasite burden

BACKGROUND: Schistosomiasis is a major parasitic disease affecting over 200 million people in the developing world with a further 400 million people at risk of infection. The aim of this study was to identify a single antigen from adult Schistosoma haematobium worms and subsequently use this antigen to study the development of schistosome-acquired immunity in a human population. METHODS: The full-length cDNA sequence of a S. haematobium protein, a putative orthologue of the S. mansoni tegumental antigen Sm13, was obtained from a cDNA library of adult S. haematobium worms and named Sh13 following a small-scale expressed sequence tags (EST) project. The recombinant Sh13 protein expressed in E. coli, was used to investigate immuno-epidemiological patterns in 147 Zimbabweans (7–18 years old) exposed to S. haematobium. RESULTS: Sequence analysis of the full-length cDNA sequence of the S. haematobium protein Sh13, indicated that the protein has an N-terminal signal peptide and encodes an 85-amino acid mature protein with a highly conserved predicted transmembrane domain (86 % identity with the S. mansoni tegumental antigen Sm13). The recombinant Sh13 protein was used in ELISA assays to determine the reactivity of sera from the study participants. Antibody responses against Sh13 were predominantly IgG3 isotype compared to responses against crude worm antigens which were predominantly IgG1 and IgG4. The relationship between anti-Sh13 IgG3 levels and infection intensity varied significantly with host age. The youngest children (7–10 years old) had relatively low levels of both infection and anti-Sh13 IgG3. In older children (11–12 years old) rising infection levels were accompanied by a significant increase in anti-Sh13 IgG3 levels. Subsequently, infection intensity declined significantly in 13–18 year olds but levels of the antibody continued to rise. The changing relationship between infection intensity and anti-Sh13 IgG3 levels with host age is consistent with the profile of a protective immune response predicted from theoretical work. CONCLUSION: We have identified and characterised a novel S. haematobium antigen Sh13, a putative tegumental protein, and shown that it is recognised predominantly by IgG3 antibodies from people infected with/exposed to S. haematobium parasites. We have also shown that, the anti-Sh13 IgG3 response is maximal in older individuals with the lowest infection intensity, and that the age profile of the relationship between anti-Sh13 IgG3 and infection intensity is consistent with that predicted by theoretical work for a protective response stimulated by and directed against adult worms