Brucella spp noncanonical LPS: structure, biosynthesis, and interaction with host immune system

Brucella spp. are facultative intracellular pathogens that have the ability to survive and multiply in professional and non-professional phagocytes, and cause abortion in domestic animals and undulant fever in humans. Several species are recognized within the genus Brucella and this classification is mainly based on the difference in pathogenicity and in host preference. Brucella strains may occur as either smooth or rough, expressing smooth LPS (S-LPS) or rough LPS (R-LPS) as major surface antigen. This bacterium possesses an unconventional non-endotoxic lipopolysaccharide that confers resistance to anti-microbial attacks and modulates the host immune response. The strains that are pathogenic for humans (B. abortus, B. suis, B. melitensis) carry a smooth LPS involved in the virulence of these bacteria. The LPS O-chain protects the bacteria from cellular cationic peptides, oxygen metabolites and complement-mediated lysis and it is a key molecule for Brucella survival and replication in the host. Here, we review i) Brucella LPS structure; ii) Brucella genome, iii) genes involved in LPS biosynthesis; iv) the interaction between LPS and innate immunity

Human T Cell and Antibody-Mediated Responses to the Mycobacterium tuberculosis Recombinant 85A, 85B, and ESAT-6 Antigens

Tuberculosis remains a major health problem throughout the world causing large number of deaths. Effective disease control and eradication programs require the identification of major antigens recognized by the protective responses against M. tuberculosis. In this study, we have investigated humoral and cellular immune responses to M. tuberculosis-specific Ag85A, Ag85B, and ESAT-6 antigens in Brazilian patients with pulmonary (P, n = 13) or extrapulmonary (EP, n = 12) tuberculosis, patients undergoing chemotherapy (PT, n = 23), and noninfected healthy individuals (NI, n = 7). Compared to NI, we observed increased levels of IgG1 responses to Ag85B and ESAT-6 in P and PT groups. Regarding cellular immunity, Ag85A and ESAT-6 were able to discriminate P, PT, and EP patients from healthy individuals by IFN-γ production and P and PT groups from EP individuals by production of TNF-α. In summary, these findings demonstrate the ability of Ag85A, Ag85B, and ESAT-6 to differentiate TB patients from controls by IgG1, IFN-γ and TNF-α production

Drogas e políticas públicas: reflexões com ênfase na prevenção

O consumo de substâncias psicoativas acompanha a evolução da história da humanidade. O ser humano tem feito uso de drogas através dos tempos nos mais variados contextos e pelas mais diversas motivações, sendo que, na atualidade, verifica-se que essa utilização tem colocado muitos desafios à sociedade mundial.  Tendo em vista que se trata de um fenômeno complexo e multifatorial, observa-se que as políticas públicas de enfrentamento a este problema não têm sido efetivas. No Brasil, em especial, as ações e programas neste sentido tem se demonstrado tardias, mínimas e desarticuladas. Dessa forma, a proposta deste trabalho é contribuir com reflexões teóricas acerca dessa questão, com particular ênfase ao âmbito da prevenção

Fotoperíodo e temperatura na germinação de sementes de maracujá 'SCS437 Catarina'

The passion fruit (Passiflora edulis Sims.) propagates by sexual reproduction and presents slow and uneven seed germination. This work has the goal of identifying a temperature and photoperiod that provide greater germination of the cultivar SCS 437 Catarina. We used an entirely randomized experimental design in a 2 x 3 + 1 factorial: two temperatures (alternating between 20/30 ºC and constant 25 ºC) and three photoperiods (8/16 – 8 hours of light and 16 hours of darkness; 12/12 – 12 hours of light and 12 hours of darkness; and absence of light), and for alternating temperature, an absence of light treatment was added, being classified as neutral photoblastic, and at a constant temperature of 25 ºC made germination unfeasible, while the 20/30 ºC alternating temperatures provided an average germination of 75%. The seeds showed an indifferent behavior to light, and the temperature alternated with 12/12 h photoperiod was the ideal condition to promote a higher percentage of germination.O maracujazeiro-azedo (Passiflora edulis Sims.) é propagado por via sexuada e apresenta germinação lenta e desuniforme das sementes. O objetivo do trabalho foi identificar a temperatura e o fotoperíodo que proporcionam maior germinação da cultivar SCS 437 Catarina. Foi utilizado o delineamento inteiramente casualizado em esquema fatorial 2 x 3 + 1: duas temperaturas (alternada de 20/30 ºC e constante de 25 ºC) e três fotoperíodos (8/16 - 8 horas de luz e 16 horas de escuro; 12/12 - 12 horas de luz e 12 horas de escuro; e ausência de luz), e para temperatura alternada foi adicionado um tratamento de ausência de luz, sendo classificadas como fotoblásticas neutras, e a temperatura constante de 25 ºC inviabilizou a germinação, enquanto a temperatura alternada 20/30 ºC proporcionou germinação de 75 %. As sementes apresentaram um comportamento indiferente à luz, e a temperatura alternada com fotoperíodo 12/12 h foi a condição ideal para promover maior percentual de germinação

Host Susceptibility to Brucella abortus Infection Is More Pronounced in IFN-γ knockout than IL-12/β2-Microglobulin Double-Deficient Mice

Brucella abortus is a facultative intracellular bacterial pathogen that causes abortion in domestic animals and undulant fever in humans. IFN-γ, IL-12, and CD8+ T lymphocytes are important components of host immune responses against B. abortus. Herein, IFN-γ and IL-12/β2-microglobulin (β2-m) knockout mice were used to determine whether CD8+ T cells and IL-12-dependent IFN-γ deficiency would be more critical to control B. abortus infection compared to the lack of endogenous IFN-γ. At 1 week after infection, IFN-γ KO and IL-12/β2-m KO mice showed increased numbers of bacterial load in spleens; however, at 3 weeks postinfection (p.i.), only IFN-γ KO succumbed to Brucella. All IFN-γ KO had died at 16 days p.i. whereas death within the IL-12/β2-m KO group was delayed and occurred at 32 days until 47 days postinfection. Susceptibility of IL-12/β2-m KO animals to Brucella was associated to undetectable levels of IFN-γ in mouse splenocytes and inability of these cells to lyse Brucella-infected macrophages. However, the lack of endogenous IFN-γ was found to be more important to control brucellosis than CD8+ T cells and IL-12-dependent IFN-γ deficiencies

Schistosoma mansoni Tegument Protein Sm29 Is Able to Induce a Th1-Type of Immune Response and Protection against Parasite Infection

Schistosomiasis is the most important human helminth infection in terms of morbidity and mortality. Although the efforts to develop a vaccine against this disease have experienced failures, a new generation of surface antigens revealed by proteomic studies changed this scenario. Our group has characterized the protein Sm29 described previously as one of the most exposed and expressed antigens in the outer tegument of Schistosoma mansoni. Studies in patients living in endemic areas for schistosomiasis revealed high levels of IgG1 and IgG3 anti-Sm29 in resistant individuals. In this study, confocal microscope analysis showed Sm29 present in the surface of lung-stage schistosoluma and adult worms. Recombinant Sm29, when used as vaccine candidate, induced high levels of protection in mice. This protection was associated with a typical Th1 immune response and reduction of worm burden, liver granulomas and in intestinal eggs. Further, microarray analysis of worms recovered from vaccinated mice showed significant down-regulation of several genes encoding previously characterized vaccine candidates and/or molecules exposed on the surface, suggesting an immune evasion strategy of schistosomes under immune attack. These results demonstrated that Sm29 as one of the important antigens with potential to compose a vaccine against schistosomiasis

Níveis críticos e faixas de suficiência de nutrientes derivados de métodos de avaliação do estado nutricional da palma-de-óleo

The objective of this work was to determine critical levels and nutrient sufficiency ranges for oil palm (Elaeis spp.), using methods for assessing the nutritional status of the plants. The methods of mathematical chance (ChM), diagnosis and recommendation integrated system (DRIS), and compositional nutrient diagnosis (CND), besides the critical level obtained by the reduced normal distribution (DNR), were used in productivity data and in nutrient content of 144 leaf samples of oil palm plantations in the state of Pará, Brazil. The regressions of the DRIS and CND indexes with leaf nutrient contents were all significant, and the lowest coefficient of determination was found for N. The sufficiency range intervals obtained with the ChM, DRIS, and CND methods in the nutritionally balanced stands were, in general, narrower than the ones reported in the literature, with few concordant diagnostics, mainly for K. The critical levels obtained with DNR were within the nutritional range intervals obtained with the other methods. ChM, DRIS, CND, and DNR are suited methods for obtaining nutritional reference values, and they indicated N, Ca, S, Mn, and Zn as the nutrients with the highest frequency of deficiency in the evaluated oil palm orchards.O objetivo deste trabalho foi determinar níveis críticos e faixas de suficiência de nutrientes para a palma-de-óleo (Elaeis spp.), a partir de métodos de avaliação do estado nutricional das plantas. Utilizaram-se os métodos chance matemática (ChM), sistema integrado de diagnose e recomendação (DRIS) e diagnose da composição nutricional (CND), além da avaliação do nível crítico obtido pela distribuição normal reduzida (DNR) em dados de produtividade e do teor de nutrientes de 144 amostras foliares de plantios no Pará. As regressões dos índices DRIS e CND com os teores foliares foram todas significativas, e o menor coeficiente de determinação foi encontrado para N. Os intervalos das faixas de suficiência obtidos com os métodos ChM, DRIS e CND nos talhões nutricionalmente equilibrados foram, em geral, mais estreitos do que os reportados na literatura, com poucos diagnósticos concordantes, sobretudo para K. Os níveis críticos obtidos pela DNR situaram-se dentro do intervalo das faixas nutricionais obtidas com os outros métodos. Os métodos ChM, DRIS, CND e DNR são adequados para a obtenção de valores de referência nutricionais e indicaram N, Ca, S, Mn e Zn como os nutrientes com maior frequência de deficiência nos talhões de palma-de-óleo avaliados

Efeito do expurgo sobre a preservação do alho armazenado

Stored garlic (Allium sativum L.) is damaged by she insects Plodia interpunctella (Huber), Ephestia cautela (Walker), Ephestia alutella (Hubner) (Lepidoptera, Phycitidae), and Araecerus fasciculatus (De Geer) (Coleoptera, Anthribidae), and the mite Eriophyes tulipae (Keifer 1938) (Acariformes, Eriophyidae). Phosphin and methyl bromide fumigants were tested at four dosage levels and three applications for protection of stored garlic. One sample treated with 4% malathion powder after fumigation and one untreated sample were included as checks. Fumigation plus malathion application showed to be efficient to protect stored garlic from moths and mites. Phosphin was as efficient as methyl bromide for the control of both insects and mites. Damage was less in the malathion treated sample (34.9% damaged bulbils by moths and 45% by mites). Both fumigants were effective in protecting stored garlic. However, methyl bromide at the dosage level of 15 cm3/m3 decreased bulbing of garlic.O alho (Allium sativum L.) armazenado é praguejado pelos insetos Plodia interpunctella (Hubner), Ephestia cautella (Walker), Ephestia elutella (Hubner), (Lepidoptera, Phycitidae), Araecerus fasciculatus (De Geer) (Coleoptera, Anthribidae), e pelo ácaro Eriophyes tulipae (Keifer 1938) (Acariformes, Eriophyidae). Testou-se o expurgo com brometo de metila e fosfina em quatro dosagens diferentes e três aplicações. Todas as parcelas expurgadas foram tratadas com malation 4% após o expurgo. Usaram-se duas testemunhas não expurgadas: uma, tratada com malation, pó, 4%, e outra, sem defensivo. O expurgo + malation demonstrou ser uma prática eficaz para proteger o alho armazenado dos ataques das traças e do ácaro. A fosfina e o brometo de meta igualaram-se no controle destas pragas; as dosagens de 5 cm3/m3 para o brometo e de uma pastilha/m3 para a fosfina foram suficientes numa única aplicação, no primeiro caso, e em três aplicações (outubro, dezembro e fevereiro) no segundo caso. Estas dosagens não prejudicaram a brotação, mas quando a dosagem de brometo de metila foi elevada para 15 cm3/m3, observou-se prejuízo na brotação. O malation, isoladamente, se bem que dando um controle superior à testemunha sem tratamento, não foi eficaz no controle das traças e do ácaro. A presença destas pragas nos bulbos não influenciou o número de brotos resultantes nem o seu peso

Management and conservation of sour passion fruit seeds

A produção de mudas de maracujazeiro-azedo (Passiflora edulis Sims.) depende da disponibilidade de sementes de alta qualidade fisiológica, genética e fitossanitária. O objetivo deste trabalho foi sistematizar indicações técnicas para a determinação do ponto de colheita, manejo e conservação das sementes de maracujazeiro-azedo. A produção de sementes deve ser a partir de frutos completamente maduros de plantas selecionadas. A remoção do arilo deve ser manual, com auxílio de uma peneira. A secagem deve ser realizada à sombra, em ambiente ventilado, sobre papel. Pode-se utilizar embalagens permeáveis e impermeáveis para a conservação das sementes, tanto em temperatura ambiente (máximo três meses, quanto em geladeira (até um ano). A semeadura pode ser de forma direta, nos recipientes de produção das mudas ou em bandejas de 128 células, para posterior transplantio aos recipientes definitivos.The production of passion fruit seedlings (Passiflora edulis Sims.) depends on the availability of seeds with high physiological, genetic and phytosanitary quality. The objective of this work was to develop technical standards to determine the harvest point, management and conservation of passion fruit seeds. Seed production must be from fully ripe fruits of selected plants. Removal of the aril must be manual, with the aid of a sieve. Drying must be carried out on paper and under shade, in a ventilated environment. Permeable and impermeable packaging can be used to conserve the seeds, either at room temperature (maximum three months) or in a refrigerator (up to one year). The sowing can be done directly, in the seedling production recipients or in 128 cell trays, for later transplantation to the definitive recipients