Caracterização funcional de proteínas hipotéticas de Leptospira interrogans como adesinas e potenciais antígenos vacinais e para diagnóstico / Functional characterization of hypothetical proteins in Leptospira interrogans as adhesins and potential vaccine and diagnostic antigens

Leptospira spp. constitui um grupo de bactérias espiroquetas gram-negativas englobando espécies saprofíticas, intermediárias e patogênicas, sendo as últimas agentes causadores da leptospirose, doença zoonótica de alcance mundial e endêmica em regiões tropicais em desenvolvimento. O crescente número de espécies identificadas de leptospiras destaca ainda mais sua diversidade genética e mecanismos de virulência únicos, muitos deles com função ainda desconhecida. Esforços para o desenvolvimento de novas vacinas com proteção cruzada e efeito duradouro revelaram possíveis candidatos vacinais que necessitam ser adequadamente validados, sendo assim, há ainda uma urgente necessidade de uma vacina universal contra a leptospirose capaz de controlar e reduzir os surtos cada vez mais frequentes da doença. Adesinas são importantes fatores de virulência em diversos patógenos, constituindo antígenos promissores para o desenvolvimento de vacinas contra a leptospirose, assim como para o desenvolvimento de métodos diagnósticos mais rápidos e precisos. Previamente, foram identificadas três proteínas hipotéticas conservadas em L. interrogans pela técnica de phage display, denominadas arbitrariamente como LepA069, LepA962 e LepA388. A expressão do gene codificador da proteína LepA069 apresentou aumento de aproximadamente 70 % em animais infectados por leptospiras virulentas, representando a primeira evidência funcional desta proteína ainda desconhecida. Porções recombinantes da lipoproteína hipotética LepA962 (LepA962_Nt e LepA962_Phg) foram obtidos, sendo demonstrada a forte interação da proteína LepA962_Phg, contendo a sequência identificada por phage display, com laminina, fibronectina plasmática, colágeno I e fibrinogênio de maneira dose-dependente. Adicionalmente, LepA962_Phg apresentou ligação às células VERO e à sua matriz extracelular secretada, e o soro obtido a partir desta proteína recombinante foi capaz de se ligar à superfície de leptospiras virulentas, indicando que LepA962_Phg pode representar um importante domínio de interação entre as leptospiras e seu hospedeiro. Finalmente, a proteína LepA388 pertencente a uma extensa família de proteínas modificadoras de virulência com função desconhecida (DUF_61), presente apenas nas leptospiras patogênicas mais virulentas, apresentou aumento na expressão de seu gene codificador em animais infectados por leptospiras virulentas de acordo com dados na literatura. Além disso, porções recombinantes da região Nterminal desta proteína apresentaram ligação a laminina, colágenos I e IV, vitronectina e fibronectinas plasmática e celular, principalmente considerando a sequência identificada por phage display. Estes dados reforçam as predições de modelos tridimensionais da proteína LepA388 e de outros membros da família DUF_61, as quais identificam domínios semelhantes a toxinas (como abrina e CARDS) responsáveis pela ligação e internalização celulares nos hospedeiros. Dados recentes sugerem um possível papel citotóxico desempenhado pelas proteínas desta família em leptospiras, as quais podem também ser consideradas potenciais candidatas vacinais e para diagnóstico da leptospirose, devido à sua distribuição restrita em espécies e cepas patogênicas de importância para saúde humana.

Leptospira spp. constitutes a group of gram-negative spirochete bacteria comprising saprophytic, intermediate and pathogenic species, the last being causative agents of leptospirosis, a zoonotic disease of worldwide extent and endemic in developing tropical regions. The growing number of identified leptospiral species further highlights their genetic diversity and unique virulence mechanisms, many of them with unknown function. Efforts to develop new vaccines with cross-protection and long-lasting effect have revealed possible vaccine candidates that need to be properly validated. Therefore, there is still an urgent need for a universal vaccine against leptospirosis capable of controlling and reducing the increasing outbreaks of the disease. Adhesins are important virulence factors in several pathogens, constituting promising antigens for the development of vaccines against leptospirosis, as well as for the development of faster and more accurate diagnostic methods. Previously, three conserved hypothetical proteins in L. interrogans were identified by phage display technique, arbitrarily named as LepA069, LepA962 and LepA388. Expression of the LepA069 encoding gene showed an increase of approximately 70 % in animals infected by virulent leptospires, representing the first functional evidence of this still unknown protein. Recombinant portions of the hypothetical lipoprotein LepA962 (LepA962_Nt and LepA962_Phg) were obtained, demonstrating the strong interaction of the LepA962_Phg protein, containing the sequence identified by phage display, with laminin, plasma fibronectin, collagen I and fibrinogen in a dose-dependent manner. Furthermore, LepA962_Phg showed binding to VERO cells and its secreted extracellular matrix, and the serum obtained from this recombinant protein was able to bind to the surface of virulent leptospires, indicating that LepA962_Phg may represent an important domain of interaction between leptospires and its host. Finally, LepA388 protein belonging to an extensive family of virulence modifying proteins with unknown function (DUF_61), present only in the most virulent pathogenic leptospires, showed an increase in the expression of its encoding gene in animals infected by virulent leptospires according to data in literature. Moreover, recombinant portions of the N-terminal region of this protein showed binding to laminin, collagens I and IV, vitronectin and plasma and cell fibronectins, especially considering the sequence identified by phage display. These data support the predictions of three-dimensional models of the LepA388 protein and other members of the DUF_61 family, which identify toxin-like domains (such as abrin and CARDS) responsible for cellular binding and internalization in hosts. Recent data suggest a possible cytotoxic role played by proteins of this family in leptospires, which can also be considered potential vaccine candidates and antigens for diagnosis, due to their restricted distribution in pathogenic species and strains of importance to human health

Expressão e localização celular da diguanilato ciclase DgcP em Pseudomonas aeruginosa / Expression and cell localization of the diguanylate cyclase DgcP in Pseudomonas aeruginosa

A bactéria Gram-negativa Pseudomonas aeruginosa é um patógeno oportunista frequentemente associado a vítimas de queimaduras graves ou indivíduos com fibrose cística, sendo os isolados resistentes a carbepenêmicos dessa espécie considerados pela OMS como uma das maiores ameaças ao controle de infecções. O estabelecimento da infecção por esse patógeno é dependente de uma série de fatores de virulência, entre eles o pilus tipo IV (T4P), que possui papel importante na adesão a superfícies e motilidade do tipo twitching, essenciais para a colonização do hospedeiro. Uma das moléculas importantes na diferenciação entre as formas séssil e planctônica de P. aeruginosa é o segundo mensageiro bis-(3,5)-di-guanosina monofosfato cíclico (c-di-GMP), cuja síntese é feita enzimaticamente por diguanilato ciclases (DGCs). DgcP é uma DGC localizada nos polos da célula, que tem sua atividade de síntese de c-di-GMP aumentada na presença da proteína FimV, essencial para a montagem do T4P em P. aeruginosa. Neste trabalho, ensaios de microscopia de fluorescência, organização e expressão gênica foram realizados com o objetivo de aumentar a compreensão sobre o papel de DgcP em relação a sua expressão e aos fatores que regulam o T4P de P. aeruginosa. A proteína DgcP em fusão com mNeonGreen no C-terminal, expressa a partir do locus cromossômico, se localiza de maneira predominantemente bipolar tanto na linhagem selvagem quanto nos mutantes ΔpilA, ΔpilR e ΔchpA, evidenciando que seu padrão de localização não depende dos sistemas de regulação Pil-Chp e PilS-PilR. Ensaios de RT-PCRmostraram que dgcP se encontra em operon com PA14_72430 e dsbA1, indicando um papel celular conjunto entre esses genes, até o momento, desconhecido. Por fim, ensaios de qRT-PCR revelaram que os níveis de mRNA de dgcP são invariáveis nas linhagens WT, ΔpilA, ΔpilR, ΔchpA e ΔfimV, cultivadas em meio líquido ou meio sólido. Os resultados aqui mostrados, combinados com trabalhos prévios do nosso e de outros grupos, sugerem que DgcP é uma diguanilato ciclase responsável por geração constante de c-di-GMP nos polos da célula, possivelmente, atuando na sinalização local dependente do dinucleotídeo cíclico, cuja localização e atividade não são dependentes dos sistemas de regulação que atuam sobre o T4P

The Gram-negative bacterium Pseudomonas aeruginosa is an opportunistic pathogen often associated with severe burn victims or individuals with cystic fibrosis, which carbapenem-resistant isolates were classified by th World Health Organization classified one of the greatest threats to infection control. The establishment of infection by this pathogen is dependent on a series of virulence factors, including the type IV pilus (T4P), which plays an important role in adhesion to surfaces and twitching motility, essential features for host colonization. Bis-(3',5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a second messenger that involved in processes of biofilm formation, motility, and virulence. The diguanylate cyclase DgcP synthetizes cdi-GMP and it is located at the cell poles, and its activity depends on the scaffold protein FimV, essential for T4P assembly in P. aeruginosa. By increasing c-di-GMP levels, DgcP decreases flagellum-dependent motility and increases biofilm formation. In this work, fluorescence microscopy, gene organization and expression assays were performed to understand the whether DgcP localization and expression are under the control of T4P regulatory proteins. Fluorescence microscopy analysis showed that DgcP localizes predominantly at both cell poles in ΔpilA, ΔpilR, and ΔchpA mutants, showing that its localization pattern does not depend on the Pil-Chp and PilS-PilR systems. Furthermore, RT-PCR assays showed that dgcP is found in an operon with PA14_72430 and dsbA1, indicating an unknown putative related cellular role for these genes. Finally, qRT-PCR assays indicated that DgcP expression is invariant in ΔpilA, ΔpilR, ΔchpA, and ΔfimV mutants, either in liquid or solid medium. The results shownhere, combined with previous work by ours and other groups, suggest that DgcP is a diguanylate cyclase responsible for constant generation of c-di-GMP at the cell poles, possibly acting in local signaling dependent on the cyclic dinucleotide, but that is not under the control of the known T4P regulatory systems

Interactions between probiotic and oral pathogenic strains.

More than 6 billion bacteria and other microorganisms live in the adult oral cavity. As a result of any deleterious effect on this community, some microorganisms will survive better than others, which may trigger pathogenic processes like caries, halitosis, gingivitis or periodontitis. Oral dysbiosis is among the most frequent human health hazards globally. Quality of life of patients deteriorates notably, while treatments are often unpleasant, expensive and irreversible, e.g. tooth loss. In the experiments reported here, we investigated the individual interactions between 8 pathogenic and 8 probiotic strains and a commercially available probiotic product. Almost all pathogens, namely Fusobacterium nucleatum, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Streptococcus mutans, Streptococcus oralis, Streptococcus gordonii, Enterococcus faecalis and Prevotella buccae are pathogens frequently occurring in the oral cavity. The used probiotic strains were Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus delbrueckii, Bifidobacterium thermophilum and two Streptococcus dentisani isolates. Using a modified agar diffusion method, we investigated capability of the probiotic bacteria to prevent the growth of the pathogenic ones in order to identify candidates for future therapeutic treatments. The results indicated successful bacteriocin production, i.e. growth inhibition, against every pathogenic bacterium by at least 5 probiotic strains.

Efeitos in vitro e in vivo dos inibidores da protease do HIV Atazanavir e Darunavir nos fatores de virulência de Candida albicans: formação de biofilme, filamentação e infecção em modelo de Galleria mellonella / In vitro and in vivo effects of the HIV Protease Inhibitors Atazanavir and Darunavir in virulence factors of Candida albicans: biofilm formation, hyphae formation and infection in Galleria mellonella model

Candida albicans é um fungo que habitualmente coloniza superfícies mucosas de humanos e pode assumir caráter patogênico a depender de fatores do hospedeiro. Portadores da Síndrome da Imunodeficiência Humana, causada pelo Vírus da Imunodeficiência Humana (HIV), são propícios a apresentar candidose nas mucosas devido a imunodeficiência celular que apresentam. A introdução da Terapia Antirretroviral (TARV), em especial o surgimento dos Inibidores da Protease do HIV (IPs-HIV), reduziu drasticamente a incidência e prevalência destas patologias ao longo dos anos. Estudos clínicos e epidemiológicos com IPs-HIV de primeira geração demostraram que tal redução não se deve exclusivamente à melhora imunológica promovida pela TARV, e pesquisas in vitro já demonstraram propriedades antifúngicas e antibiofilme de alguns IPs-HIV de primeiras gerações em C. albicans. Sendo assim, o objetivo deste estudo foi avaliar os efeitos do Atazanavir (ATV) e Darunavir (DRV), dois IPs-HIV de segunda e terceira geração respectivamente em uso clínico atual no Brasil, em diferentes fatores de virulência de C. albicans. Para isso foram realizados estudos com duas cepas clínicas de C. albicans isoladas de lesões de candidose orofaríngea de pacientes portadores de HIV para avaliar a ação in vitro das drogas na morfogênese, formação de biofilme (contagem de células viáveis e quantificação de biomassa) e na expressão dos genes de virulência BRC1 e SAP2, e in vivo no efeito protetor desses medicamentos na infecção experimental por C. albicans em modelo de Galleria mellonella. Os dados foram analisados por teste t, ANOVA, Kruskal-Wallis, Dunn e Kaplan-Meier (p<0,05). A Concentração Inibitória Mínima (CIM) para ambos os IPs-HIV testados foi 512 µg/mL. Nos biofilmes, a redução na contagem de UFC/mL de C. albicans nos grupos tratados com IPs-HIV foi de até 6,81 Log. A biomassa dos biofilmes tratados também sofreu reduções significantes para ATV (82%), DRV (81%) comparada ao grupo controle.DRV e ATV promoveram redução estatisticamente significante de expressão gênica de SAP2 e BRC1, respectivamente, quando comparados ao controle (p<0,05). Em relação à morfogênese de C. albicans, ATV e DRV inibiram significativamente a formação de hifas (p=0,0183). No estudo in vivo, o uso profilático de ATV e DRV em G. mellonella infectadas com C. albicans prolongou em até 40% a sobrevivência das larvas (p=0,0004). Conclui-se que ATV e DRV inibiram a filamentação e apresentaram atividade antifúngica, antibiofilme e na expressão de genes de fatores de virulência de C. albicans e preveniram candidose em G. mellonella(AU)

Candida albicans is a fungus that usually colonizes mucous surfaces of humans and can assume pathogenic character depending on host factors. Patients with Human Immunodeficiency Syndrome, caused by the Human Immunodeficiency Virus (HIV), are favorable to present mucous candidosis due to the cellular immunodeficiency they present. The introduction of Antiretroviral Therapy (ART), especially the emergence of HIV Protease Inhibitors (HIV-PI), has drastically reduced the incidence and prevalence of these mycosis over the years. Clinical and epidemiological studies with firstgeneration HIV-PIs have shown that this reduction is not exclusively due to the immunological improvement promoted by ART, and in vitro research has already demonstrated antifungal and antibiofilm properties of firsts-generations HIV-PIs on C. albicans. Thus, the aim of this study was to evaluate the effects of Atazanavir (ATV) and Darunavir (DRV), two HIV-PIs of second and third generation respectively currently in clinical use in Brazil, on virulence factors of C. albicans. For this purpose, studies were carried out with two clinical strains of C. albicans isolated from lesions of oropharyngeal candidosis of HIV positive patients to evaluate in vitro action of the drugs on morphogenesis, biofilm formation (number of viable cell and biomass determination) and virulence factor genes BRC1 and SAP2 expression and in vivo on the protective effect of these drugs on experimental infection by C. albicans in Galleria mellonella model. Data were analyzed by t Student, ANOVA, Kruskal-Wallis and Dunn and Kaplan-Meier (p<0.05) tests. The Minimum Inhibitory Concentration (MIC) for both tested HIV-PIs was 512 µg/mL. In biofilms, a reduction in the CFU/mL count of C. albicans in the groups treated with HIV-PIs was up to 6.81 log. The biomass of biofilms also suffered significant reductions for ATV (82%) and DRV (81%) compared to the control group. DRV and ATV statistically significantly downregulated the expression of SAP2 and BRC1 genes respectively (p<0,05). Regarding the morphogenesis of C. albicans, ATV and DRV inhibited the formation of hyphae (p = 0.0183). In the in vivo study, the prophylactic use of ATV and DRV in G. mellonella infected with C. albicans prolonged larval survival by up to 40% (p = 0.0004). We can conclude that ATV and DRV inhibited filamentation and showed antifungal activity, being able to inhibit growth, formation and virulence factors gene expression of C. albicans biofilm and prevented candidosis in G. mellonel(AU)

Lectin drug conjugate therapy for colorectal cancer.

Drug resistance represents an obstacle in colorectal cancer (CRC) treatment because of its association with poor prognosis. rBC2LCN is a lectin isolated from Burkholderia that binds cell surface glycans that have fucose moieties. Because fucosylation is enhanced in many types of cancers, this lectin could be an efficient drug carrier if CRC cells specifically present such glycans. Therefore, we examined the therapeutic efficacy and toxicity of lectin drug conjugate therapy in CRC mouse xenograft models. The affinity of rBC2LCN for human CRC cell lines HT-29, LoVo, LS174T, and DLD-1 was assessed in vitro. The cytocidal efficacy of a lectin drug conjugate, rBC2LCN-38 kDa domain of pseudomonas exotoxin A (PE38) was evaluated by MTT assay. The therapeutic effects and toxicity for each CRC cell line-derived mouse xenograft model were compared between the intervention and control groups. LS174T and DLD-1 cell lines showed a strong affinity for rBC2LCN. In the xenograft model, the tumor volume in the rBC2LCN-PE38 group was significantly reduced compared with that using control treatment alone. However, the HT-29 cell line showed weak affinity and poor therapeutic efficacy. No significant toxicities or adverse responses were observed. In conclusion, we demonstrated that rBC2LCN lectin binds CRC cells and that rBC2LCN-PE38 significantly suppresses tumor growth in vivo. In addition, the efficacy of the drug conjugate correlated with its binding affinity for each CRC cell line. These results suggest that lectin drug conjugate therapy has potential as a novel targeted therapy for CRC cell surface glycans.

Salmonella enterica serovar Typhimurium sseK3 induces apoptosis and enhances glycolysis in macrophages.

BACKGROUND: Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important infectious disease pathogen that can survive and replicate in macrophages. Glycolysis is essential for immune responses against S. Typhimurium infection in macrophages, and is also associated with apoptosis. S. Typhimurium secreted effector K3 (SseK3) was recently identified as a novel translated and secreted protein. However, there is no study about the role of sseK3 in the relationship between apoptosis and glycolysis in cells infected with S. Typhimurium. It is unclear whether this protein exerts a significant role in the progress of apoptosis and glycolysis in S. Typhimurium-infected macrophages. RESULTS: Macrophages were infected with S. Typhimurium SL1344 wild-type (WT), ΔsseK3 mutant or sseK3-complemented strain, and the effects of sseK3 on apoptosis and glycolysis were determined. The adherence and invasion in the ΔsseK3 mutant group were similar to that in the WT and sseK3-complemented groups, indicating that SseK3 was not essential for the adherence and invasion of S. Typhimurium in macrophages. However, the percentage of apoptosis in the ΔsseK3 mutant group was much lower than that in the WT and sseK3-complemented groups. Caspase-3, caspase-8, and caspase-9 enzyme activity in the ΔsseK3 mutant group were significantly lower than in the WT group and sseK3-complemented groups, indicating that sseK3 could improve the caspase-3, caspase-8, and caspase-9 enzyme activity. We also found that there were no significant differences in pyruvic acid levels between the three groups, but the lactic acid level in the ΔsseK3 mutant group was much lower than that in the WT and sseK3-complemented groups. The ATP levels in the ΔsseK3 mutant group were remarkably higher than those in the WT and sseK3-complemented groups. These indicated that the sseK3 enhanced the level of glycolysis in macrophages infected by S. Typhimurium. CONCLUSIONS: S. Typhimurium sseK3 is likely involved in promoting macrophage apoptosis and modulating glycolysis in macrophages. Our results could improve our understanding of the relationship between apoptosis and glycolysis in macrophages induced by S. Typhimurium sseK3.

Evaluation of Caco-2 cells response to Listeria monocytogenes virulence factors by RT-PCR.

Listeria monocytogenes expresses various virulence factors enabling the invasion and multiplying in host cells, and together induces cytokines transcription. In order to explore the relationship between virulence factors of L. monocytogenes wild-type EGD-e and cellular response in human colonic epithelial cell line(Caco-2), we constructed mutant strains with in-frame deletions of critical virulence genes of inlA, inlB, hly, actA and virulence regulatory factor prfA from EGD-e, respectively. Compared with EGD-e, mutant strains showed significantly decreased invasion and apoptosis in Caco-2 cells. However, mutant strains were capable to evoke cytokines transcription of interleukin-8 (IL-8), mononuclear chemoattractant protein-1 (MCP-1), tumor necrosis factor-a (TNF-a), interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and CXCL-2 production in Caco-2 cells. Interestingly, EGD-e Δhly-infected Caco-2 cells showed a significant decrease of IL-6, IL-8 and MCP-1 transcription compared with EGD-e at 1 h post-infection. Simultaneously, EGD-e ΔinlB-infected cells showed a decrease in IL-6 transcription, while EGD-e ΔactA-infected cells reflected a decrease in MCP-1 transcription. Virulence genes play a role in inflammatory transcription, but the interaction between pathogenic bacteria and the host cells predominates in inflammatory transcription. Overall, the data showed cellular response of Caco-2 cells infected with EGD-e mutant strains.

Influência de extratos vegetais nos fatores de virulência de Candida albicans em biofilme: estudo in vitro / Plant extract and the virulence factors of Candida albicans

Cepas isoladas de infecções graves por Candida albicans expressam inúmeros fatores de virulência e a compreensão destes fatores permite esclarecer os mecanismos inerentes ao patógeno no processo infeccioso, assim como ferramentas terapêuticas que modulem a expressão destes fatores e permitam o controle de infecções persistentes. O objetivo deste estudo foi analisar a influência de 4 extratos vegetais no crescimento deste fungo quando em bifilme, assim como na expressão dos fatores de virulência (proteinase, fosfolipase e hemolisina) de C. albicans. Para isso, biofilmes de 48 horas de C. albicans (ATCC 18804) foram expostos a diferentes concentrações dos extratos glicólicos de Hamamelis virginiana, Persea. americana, Cynara scolymus L e Stryphnodendro barbatiman M, por 5 minutos e 24 h, para verificar a atividade antifúngica (redução em relação ao controle), e a secreção de proteinase, fosfolipase e hemolisina, utilizando meios especificos. Todos os extratos testados foram efetivos na redução do biofilme de C. albicans. Quando em contato por 5 min os extratos foram capazes de reduzir o biofilme em 50% em média, reduções mais expressivas foram encontradas depois de 24 h de exposição. O extrato de P. americana (25 mg/mL) reduziu o biofilme em 90%, em relação ao controle, seguido de C. scolymus (100 mg/mL), que reduziu em 85%. A secreção de proteinase foi alterada, tanto em 5 min como em 24 h, sendo a Pz (atividade enzimática) média de 0,69, em relação ao controle Pz= 0,49. Cynara scolymus foi o extrato que induziu a maior Pz média na concentração de 100 mg/mL, 0,73 e 0,78, quando tratados por 5 min e 24 h, respectivamente, em relação ao controle (Pz=0,48) (p<0,0001). A secreção de fosfolipase sofreu alteração depois do tratamento, sendo o extrato de S. barbatiman (100 mg/mL) o mais efetivo em 24 h, com Pz de 0,74 em relação ao controle (Pz= 0,50) (p<0,0001). A secreção de hemolisina foi alterada pela exposição ao extrato de H. virginiana (12,5 mg/mL) em 5 min de exposição. Em 24 h todos os extratos foram capazes de alterar o padrão hemolítico da cepa testada, sendo o extrato de H. virginiana (12,5 mg/mL) a apresentar Pz= 0,70. Os extratos vegetais testados demostram potencial antifúngico; e influenciam negativamente a secreção dos fatores de virulência testados, podendo ser apontados como ferramentas terapêuticas alternativas visando a redução da morbidade das infecções causadas por este patógeno (AU)

Strains isolated from severe Candida. albicans infections express numerous virulence factors, which suggest the understanding of these factors allows to clarify the mechanisms inherent to the pathogen in the infectious process, as well as therapeutic tools that modulate the expression of these factors and allow the control of persistent infections. Biofilms of 48 hours of C. albicans (ATCC 18804) were exposed to different concentrations of the glycolic extracts of Hamamelis virginiana and Persea. americana, Cynara. scolymus L and Stryphnodendron. barbatiman M, for 5 minutes and 24 h, to verify the antifungal activity, and secretion of proteinase, phospholipase and hemolysin. All extracts tested were effective in reducing the biofilm of C. albicans. When in contact for 5 min the extracts were able to reduce the mean of 50% of the biofilm. More significant reductions were found after 24 h of exposure. The extract of P. americana (25 mg/ml) reduced biofilm by 90% compared to control, followed by C. scolymus (100 mg/ml), which reduced by 85%. The enzymatic activiti (Pz) of proteinase was altered, both in 5 min and 24 h, the mean Pz being 0.69, in relation to the control Pz = 0.49. C. scolymus was the extract with the highest mean Pz at the concentration of 100 mg/ml, 0.73 and 0.78, when treated for 5 min and 24 h, respectively, in relation to the control (Pz = 0.48) (p <0,0001). Phospholipase secretion was altered after treatment, with S. barbatiman (100 mg/ml) being the most effective in 24 h, with Pz of 0.74 in relation to the control (Pz = 0.50) (p <0,0001). Hemolysin secretion was altered by exposure to H. virginiana (12.5 mg/ml) in 5 min of exposure. In 24 h all the extracts were able to change the hemolytic pattern of the tested strain, being the H. virginiana extract (12.5 mg/ml) to present Pz = 0,70. The tested plant extracts show antifungal potential; and negatively influence the secretion of the virulence factors tested, and can be indicated as alternative therapeutic tools aiming at reducing the morbidity of the infections caused by this pathogen(AU)

Inmunopatogenia de la enfermedad hipertensiva gravídica / Immune-Pathogenesis of Pregnant Hypertension

La enfermedad hipertensiva gravídica constituye una patología obstétrica relativamente frecuente. En los últimos años se ha avanzado en la comprensión de la patogenia de la enfermedad, al ser el sistema inmune uno de los actores de vital importancia en la aparición de este trastorno. Las células asesinas naturales de la decidua constituyen un componente fundamental en el remodelado vascular durante la formación de la placenta. Cuando existen alteraciones en esta población celular, se induce una isquemia placentaria que promueve la liberación de factores vasculares y mediadores de la inflamación que promueven el daño sistémico con aparición de los síntomas de la enfermedad(AU)

Pregnant hypertension is a frequent pregnancy disorder. Researchers has recentely advanced in understanding this disease pathogenesis. The immune system plays a key role in this disease onset. Decidual natural killer cells are fundamental component in vascular remodeling during placental development. When alterations occurs in this cell population, placental ischemia is induced promoting the release of vascular factors and inflammation mechanisms that cause these disease symptoms(AU)

Inmunopatogenia de la enfermedad hipertensiva gravídica / Immune-Pathogenesis of Pregnant Hypertension

La enfermedad hipertensiva gravídica constituye una patología obstétrica relativamente frecuente. En los últimos años se ha avanzado en la comprensión de la patogenia de la enfermedad, al ser el sistema inmune uno de los actores de vital importancia en la aparición de este trastorno. Las células asesinas naturales de la decidua constituyen un componente fundamental en el remodelado vascular durante la formación de la placenta. Cuando existen alteraciones en esta población celular, se induce una isquemia placentaria que promueve la liberación de factores vasculares y mediadores de la inflamación que promueven el daño sistémico con aparición de los síntomas de la enfermedad(AU)

Pregnant hypertension is a frequent pregnancy disorder. Researchers has recentely advanced in understanding this disease pathogenesis. The immune system plays a key role in this disease onset. Decidual natural killer cells are fundamental component in vascular remodeling during placental development. When alterations occurs in this cell population, placental ischemia is induced promoting the release of vascular factors and inflammation mechanisms that cause these disease symptoms(AU)

Expressão dos genes ALS3, HWP1, BCR1, TEC1, CPH1 e EFG1 de Candida albicans em biofilmes após inativação fotodinâmica / Expression of the Candida albicans genes ALS3, HWP1, BCR1, TEC1, CPH1 and EFG1 in biofilms after photodynamic inactivation

Os micro-organismos estão se tornando cada vez mais resistentes aos antimicrobianos e cepas de Candida albicans resistentes aos antifúngicos tem sido isoladas, assim, torna-se importante e necessário a realização de pesquisas que avaliem os efeitos de novos métodos terapêuticos, como a inativação fotodinâmica antimicrobiana (aPDI). Assim, o objetivo deste estudo foi verificar os efeitos da inativação fotodinâmica sobre biofilmes de Candida albicans, avaliando seus efeitos sobre a expressão dos genes TEC1 (fator de transcrição), HWP1 (proteína de parede celular das hifas), EFG1 (regulador transcricional relacionado com a morfogênese), BCR1 (regulador da formação de biofilme e da parede celular), CPH1 (regulador transcricional envolvido na morfogênese) e ALS3 (adesina) de C. albicans. Foram avaliadas 30 amostras isoladas de pacientes portadores de HIV e 30 amostras de pacientes com estomatite protética, quanto a produção de biofilme, peso seco e filamentação. Destas, foram selecionadas as amostras mais virulentas de cada grupo que apresentaram melhor capacidade de formação de biofilme e filamentação. Assim, foi utilizada uma amostra clínica de C. albicans isolada de paciente portador de HIV, uma amostra clínica de C. albicans isolada de paciente com estomatite protética e uma cepa padrão ATCC 18804. A quantificação da expressão dos genes foi relacionada à produção desses genes nas amostras clínicas e na cepa de referência utilizando-se ensaio de PCR em tempo real. Para a aPDI, foram utilizados os fotossensibilizadores azul de metileno a 300 µM e eritrosina a 400 µM sensibilizados com laser de Índio-Gálio-Alumínio-Fósforo de baixa potência (vermelho visível, 660 nm) e LED verde (532 ± 10 nm), respectivamente. Foram avaliados quatro grupos experimentais para a aPDI: a) F+L+: sensibilização com o corante e irradiação com luz; b) F+L-: somente tratamento com o fotossensibilizador; c) F-L+: somente irradiação com luz e d) F-L-: sem sensibilização com o corante e ausência de luz. Os resultados foram analisados por t-test, com um nível de significância de 5%. Após a análise fenotípica, as amostras Ca30 e 39 S foram selecionadas para a realização da aPDI. Como esperado, apenas para o grupo F+L+, quando comparado com o grupo F-L-, todos os genes analisados foram sub expressos após a aPDI. O fold-decrease para os genes ALS3, HWP1, BCR1, TEC1, CPH1 e EFG1 foram 0,73; 0,39; 0,77; 0,71; 0,67 e 0,60; para laser, respectivamente, e 0,66; 0,61; 0,50; 0,43; 0,54 e 0,66; para LED, respectivamente. Pode-se concluir que a aPDI mostrou uma redução na expressão dos genes de C. albicans, sugerindo a diminuição de sua virulência(AU)

Os micro-organismos estão se tornando cada vez mais resistentes aos antimicrobianos e cepas de Candida albicans resistentes aos antifúngicos tem sido isoladas, assim, torna-se importante e necessário a realização de pesquisas que avaliem os efeitos de novos métodos terapêuticos, como a inativação fotodinâmica antimicrobiana (aPDI). Assim, o objetivo deste estudo foi verificar os efeitos da inativação fotodinâmica sobre biofilmes de Candida albicans, avaliando seus efeitos sobre a expressão dos genes TEC1 (fator de transcrição), HWP1 (proteína de parede celular das hifas), EFG1 (regulador transcricional relacionado com a morfogênese), BCR1 (regulador da formação de biofilme e da parede celular), CPH1 (regulador transcricional envolvido na morfogênese) e ALS3 (adesina) de C. albicans. Foram avaliadas 30 amostras isoladas de pacientes portadores de HIV e 30 amostras de pacientes com estomatite protética, quanto a produção de biofilme, peso seco e filamentação. Destas, foram selecionadas as amostras mais virulentas de cada grupo que apresentaram melhor capacidade de formação de biofilme e filamentação. Assim, foi utilizada uma amostra clínica de C. albicans isolada de paciente portador de HIV, uma amostra clínica de C. albicans isolada de paciente com estomatite protética e uma cepa padrão ATCC 18804. A quantificação da expressão dos genes foi relacionada à produção desses genes nas amostras clínicas e na cepa de referência utilizando-se ensaio de PCR em tempo real. Para a aPDI, foram utilizados os fotossensibilizadores azul de metileno a 300 µM e eritrosina a 400 µM sensibilizados com laser de Índio-Gálio-Alumínio-Fósforo de baixa potência (vermelho visível, 660 nm) e LED verde (532 ± 10 nm), respectivamente. Foram avaliados quatro grupos experimentais para a aPDI: a) F+L+: sensibilização com o corante e irradiação com luz; b) F+L-: somente tratamento com o fotossensibilizador; c) F-L+: somente irradiação com luz e d) F-L-: sem sensibilização com o corante e ausência de luz. Os resultados foram analisados por t-test, com um nível de significância de 5%. Após a análise fenotípica, as amostras Ca30 e 39 S foram selecionadas para a realização da aPDI. Como esperado, apenas para o grupo F+L+, quando comparado com o grupo F-L-, todos os genes analisados foram sub expressos após a aPDI. O fold-decrease para os genes ALS3, HWP1, BCR1, TEC1, CPH1 e EFG1 foram 0,73; 0,39; 0,77; 0,71; 0,67 e 0,60; para laser, respectivamente, e 0,66; 0,61; 0,50; 0,43; 0,54 e 0,66; para LED, respectivamente. Pode-se concluir que a aPDI mostrou uma redução na expressão dos genes de C. albicans, sugerindo a diminuição de sua virulência(AU)

Peptidoglycan of Actinomyces naeslundii induces inflammatory cytokine production and stimulates osteoclastogenesis in alveolar bone resorption.

OBJECTIVE: Actinomyces naeslundii, plays an important role in forming dental biofilms and causes gingival inflammation. Although peptidoglycan, the major cell wall component of Gram-positive bacteria, has been demonstrated to induce inflammatory cytokines, little is known about the association of peptidoglycan with alveolar bone resorption. This study investigated the involvement of peptidoglycan from A. naeslundii in osteoclast formation and bone resorption. DESIGN: Osteoclast formation and function induced by peptidoglycan of A. naeslundii T14V were examined using the co-culture system of MCTC3/PA6 cells and BALB/c mouse bone marrow cells. Osteoclast formation was evaluated to count TRAP-positive multi-nuclei cells as osteoclasts. The function of osteoclasts was assessed by measuring the areas of pits absorbed. Inflammatory cytokine genes expressions, such as interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α, were examined by RT-PCR analysis using murine peritoneal macrophages. Experimental periodontitis was performed in Sprague-Dawley rats orally infected with A. naeslundii. RESULTS: TRAP-positive multi-nuclei cells and the areas of pits induced by peptidoglycan were significantly greater than controls (p<0.01). Gene expression levels of IL-1ß, IL-6, and TNF-α induced by A. naeslundii PGN were stronger than controls. In experimental periodontitis, bone loss of A. naeslundii-infected rats was comparable to that of rats induced by Porphyromonas gingivalis, which has been reported to be a periodontal pathogenic agent, being significantly greater than that of the sham group (p<0.01). CONCLUSIONS: These results suggest that peptidoglycan of A. naeslundii is an important virulence factor in the development of periodontitis.

Generation of recombinant single-chain antibodies neutralizing the cytolytic activity of vaginolysin, the main virulence factor of Gardnerella vaginalis.

BACKGROUND: Gardnerella vaginalis is identified as the predominant colonist of the vaginal tract in women with bacterial vaginosis. Vaginolysin (VLY) is a protein toxin released by G. vaginalis. VLY possesses cytolytic activity and is considered as a main virulence factor of G. vaginalis. Inhibition of VLY-mediated cell lysis by antibodies may have important physiological relevance. RESULTS: Single-chain variable fragments of immunoglobulins (scFvs) were cloned from two hybridoma cell lines producing neutralizing antibodies against VLY and expressed as active proteins in E. coli. For each hybridoma, two variants of anti-VLY scFv consisting of either VL-VH or VH-VL linked with a 20 aa-long linker sequence (G4S)4 were constructed. Recovery of scFvs from inclusion bodies with subsequent purification by metal-chelate chromatography resulted in VLY-binding proteins that were predominantly monomeric. The antigen-binding activity of purified scFvs was verified by an indirect ELISA. The neutralizing activity was investigated by in vitro hemolytic assay and cytolytic assay using HeLa cell line. Calculated apparent Kd values and neutralizing potency of scFvs were in agreement with those of parental full-length antibodies. VH-VL and VL-VH variants of scFvs showed similar affinity and neutralizing potency. The anti-VLY scFvs derived from hybridoma clone 9B4 exhibited high VLY-neutralizing activity both on human erythrocytes and cervical epithelial HeLa cells. CONCLUSIONS: Hybridoma-derived scFvs with VLY-binding activity were expressed in E. coli. Recombinant anti-VLY scFvs inhibited VLY-mediated cell lysis. The monovalent scFvs showed reduced affinity and neutralizing potency as compared to the respective full-length antibodies. The loss of avidity could be restored by generating scFv constructs with multivalent binding properties. Generated scFvs is the first example of recombinant single-chain antibodies with VLY-neutralizing activity produced in prokaryote expression system. G. vaginalis caused infections continue to be a world-wide problem, therefore neutralizing recombinant antibodies may provide novel therapeutic agents useful in the treatment of bacterial vaginosis and other diseases caused by G. vaginalis.

Pseudomonas pyocyanin inhibits wound repair by inducing premature cellular senescence: role for p38 mitogen-activated protein kinase.

Pseudomonas aeruginosa is an important nosocomial pathogen of burn wounds. Pyocyanin, a virulence factor produced by the bacterium, induces persistent intracellular oxidative stress and premature senescence in mammalian cells. Our aims were to evaluate pyocyanin levels in infected wound dressings and the potential of the toxin to influence wound repair. Surgical dressings from infected burn patients were examined for pyocyanin and normal primary human diploid fibroblasts (HDFs) were treated with comparable concentrations and their replicative ability examined. Pyocyanin was detected in the exudate of infected wound dressings in amounts up to 5.3 microg/g (mean: 2.0+/-2.3 microg/g). HDFs exposed to pyocyanin (1-50 microM; 0.2-10.5 microg/ml) underwent growth arrest at all concentrations and developed morphological characteristics associated with cellular senescence, including expression of senescence-associated beta-galactosidase. Using an in vitro wound repair model, a single exposure to pyocyanin inhibited wound repair in a concentration-dependent manner. Prior treatment with a specific p38(MAPK) inhibitor allowed cells to maintain their replicative ability and pre-senescent morphology indicating pyocyanin operates through the Erk/p38(MAPK) senescence pathway. These data support the hypothesis that bacterial virulence factors capable of inducing persistent low-level oxidative stress play a pivotal role in modulating the tissue repair response to infection by inducing premature cellular senescence.

A protease-resistant immunotoxin against CD22 with greatly increased activity against CLL and diminished animal toxicity.

Immunotoxins based on Pseudomonas exotoxin A (PE) are promising anticancer agents that combine a variable fragment (Fv) from an antibody to a tumor-associated antigen with a 38-kDa fragment of PE (PE38). The intoxication pathway of PE immunotoxins involves receptor-mediated internalization and trafficking through endosomes/lysosomes, during which the immunotoxin undergoes important proteolytic processing steps but must otherwise remain intact for eventual transport to the cytosol. We have investigated the proteolytic susceptibility of PE38 immunotoxins to lysosomal proteases and found that cleavage clusters within a limited segment of PE38. We subsequently generated mutants containing deletions in this region using HA22, an anti-CD22 Fv-PE38 immunotoxin currently undergoing clinical trials for B-cell malignancies. One mutant, HA22-LR, lacks all identified cleavage sites, is resistant to lysosomal degradation, and retains excellent biologic activity. HA22-LR killed chronic lymphocytic leukemia cells more potently and uniformly than HA22, suggesting that lysosomal protease digestion may limit immunotoxin efficacy unless the susceptible domain is eliminated. Remarkably, mice tolerated doses of HA22-LR at least 10-fold higher than lethal doses of HA22, and these higher doses exhibited markedly enhanced antitumor activity. We conclude that HA22-LR advances the therapeutic efficacy of HA22 by using an approach that may be applicable to other PE-based immunotoxins.

[Medical relevance of mycotoxins]. / Medizinische Relevanz der Mykotoxine.

There are many mycotoxins with different chemical structures and biological activities. They are present in many food items of vegetable and animal origin as well as in the air. Consequently the exposure of humans to these agents is rather common. In some particular instances the dosage taken up by the body may be considerable. The various biological effects of mycotoxins such as organ toxicity, mutagenicity, carcinogenicity, teratogenicity and modulation of the immune system are well documented by in vitro and animal experiments. Furthermore, cases of intoxication by mycotoxins are well known in veterinary medicine. However, the relevance of mycotoxins in human medicine remains largely underestimated, because material from patients with characteristic symptoms is rarely tested for mycotoxins.

Virulence factors of Escherichia coli isolated from diarrheic calves

One hundred seventy-three Escherichia coli strains isolated from calves from northwestern São Paulo State, having diarrhea were examined for the production of thermolabile (LT) and thermostable (ST) enterotoxins and for the presence of virulence factors associated with bovine colibacillosis. Eighty-five (49.1 percent) of the E.coli strains produced toxins; 53 isolates were detected as producing STa toxin, and 9 also produced LT toxin. By PCR, 23 isolates were shown to harbor only the LT-II gene. Nine (5.2 percent) isolates harbored Shiga toxin genes: four carried the stx2 gene, four the stx1 gene and one carried both. Three of the isolates showing stx1 also carried the eae gene. Among the E. coli isolates examined for susceptibility to 10 antimicrobial agents, resistance to cephalothin (46.1 percent), was most commonly observed, followed by resistances to tetracycline (45.7 percent), trimethoprim-sulfadiazine (43.3 percent) and ampicilin (41.0 percent). All isolates showed resistance to at least two antimicrobial agents; multidrug resistance was quite frequently encountered. Results showed that bovine E. coli produces some toxins and virulence factors, some of which may be involved in human disease. The isolates showed a high level of resistance to antimicrobial agents constituting a public health concern.

Cento e setenta e três cepas de Escherichia coli isoladas de bezerros com diarréia provenientes da região noroeste do estado de São Paulo foram examinadas para a produção de enterotoxinas termolábil (LT) e termoestável (ST), e examinadas quanto à presença de fatores de virulência associados a colibacilose bovina. Oitenta e cinco (49,1 por cento) das cepas de E. coli produziram toxinas, 53 cepas foram detectadas como produtoras de toxina STa, e nove dessas cepas também produziam toxina LT. Foram identificadas pela reação em cadeia de polimerase 23 cepas portadoras do gene LT-II. Nove (5,2 por cento) das cepas apresentavam os genes de toxina Shiga: quatro o gene stx 2, quatro o gene stx 1 e uma cepa apresentava os dois genes. Três das cepas que apresentavam o gene stx1 também possuiam o gene eae. Entre as cepas de E. coli examinadas quanto à susceptibilidade a 10 agentes antimicrobianos, a resistência à cefalotina (46,1 por cento) foi a mais comumente observada, seguida pelas resistências a tetraciclina (45,7 por cento), trimetropima-sulfadiazina (43,3 por cento) e ampicilina (41,0 por cento). Todas as cepas isoladas apresentaram resistência a pelo menos dois antimicrobianos, sendo a multirresistência detectada em elevada freqüência. Algumas toxinas e fatores de virulência, produzidos por essas cepas de E. coli podem estar envolvidos em doenças humanas. O alto nível de resistência a agentes antimicrobianos, apresentado pelas cepas isoladas, constitue motivo de preocupação em saúde pública.

Real-time, image-guided, convection-enhanced delivery of interleukin 13 bound to pseudomonas exotoxin.

PURPOSE: To determine if the tumor-targeted cytotoxin interleukin 13 bound to Pseudomonas exotoxin (IL13-PE) could be delivered to the brainstem safely at therapeutic doses while monitoring its distribution in real-time using a surrogate magnetic resonance imaging tracer, we used convection-enhanced delivery to perfuse rat and primate brainstems with IL13-PE and gadolinium-bound albumin (Gd-albumin). EXPERIMENTAL DESIGN: Thirty rats underwent convective brainstem perfusion of IL13-PE (0.25, 0.5, or 10 microg/mL) or vehicle. Twelve primates underwent convective brainstem perfusion of either IL13-PE (0.25, 0.5, or 10 microg/mL; n = 8), co-infusion of 125I-IL13-PE and Gd-albumin (n = 2), or co-infusion of IL13-PE (0.5 microg/mL) and Gd-albumin (n = 2). The animals were permitted to survive for up to 28 days before sacrifice and histologic assessment. RESULTS: Rats showed no evidence of toxicity at all doses. Primates showed no toxicity at 0.25 or 0.5 microg/mL but showed clinical and histologic toxicity at 10 microg/mL. Quantitative autoradiography confirmed that Gd-albumin precisely tracked IL13-PE anatomic distribution and accurately showed the volume of distribution. CONCLUSIONS: IL13-PE can be delivered safely and effectively to the primate brainstem at therapeutic concentrations and over clinically relevant volumes using convection-enhanced delivery. Moreover, the distribution of IL13-PE can be accurately tracked by co-infusion of Gd-albumin using real-time magnetic resonance imaging.

Crecimiento y Desarrollo de Colletotrichum gloeosporioides f. alatae durante su cultivo en medios líquidos / Growth and Development of Colletotrichum gloeosporioides f. alatae During Culture in Liquid Medium

Algunas características descritas como factores de virulencia para el género Colletotrichum sp. tales como la masa del micelio producido, la esporulación, la actividad poligalacturonasa y el pH del medio, fueron evaluadas durante el cultivo de C. gloeosporioides f. alatae en tres medios líquidos (Czapeck, caldo Martin y caldo papa), utilizados comúnmente para el desarrollo de hongos y en el medio de cultivo Czapeck adicionado con extracto de tubérculo de ñame como única fuente de carbono. Al cabo de 17 días de crecimiento, se obtuvieron los niveles máximos de los parámetros mencionados, al utilizar este último medio, respecto a los otros medios de cultivo evaluados. El medio de cultivo implementado con extracto de tubérculo de ñame, suministró los requerimientos nutricionales del hongo para el desarrollo de factores relacionados con los mecanismos de infección que pueden participar en su patogenicidad.

Effect of dosage on immunogenicity of a Vi conjugate vaccine injected twice into 2- to 5-year-old Vietnamese children.

In a double-blind, randomized, and placebo-controlled previous trial, the efficacy of Vi-rEPA for typhoid fever in 2- to 5-year-olds was 89.0% for 46 months. Vi-rEPA contained 25 microg of Vi and induced a greater-than-eightfold rise in immunoglobulin G (IgG) anti-Vi in all of the vaccinees tested. In this investigation, we conducted a dosage-immunogenicity study of 5, 12.5, and 25 microg of Vi-rEPA in this age group. Two doses of Vi-rEPA were injected 6 weeks apart. Blood samples were taken before and at 10 weeks (4 weeks after the second injection) and 1 year later. All postimmunization geometric mean (GM) levels were higher than the preimmune levels (P < 0.0001). At 10 weeks, the GM IgG anti-Vi level elicited by 25 microg (102 EU/ml) was higher than those elicited by 12.5 microg (74.7 EU/ml) and 5 microg (43 EU/ml) (P < 0.004): all of the children had > or = 3.52 EU/ml (estimated minimum protective level). One year later, the levels declined about sevenfold (13.3 and 11.3 versus 6.43 EU/ml, P < 0.0001) but remained significantly higher than the preimmune levels (P < 0.0001), and >96% of the children had a greater-than-eightfold rise. This study also confirmed the safety and consistent immunogenicity of the four lots of Vi-rEPA used in this and previous trials.