KARIN KIRCHGATTER
Projetos de Pesquisa
Unidades Organizacionais
LIM/49 - Laboratório de Protozoologia, Hospital das Clínicas, Faculdade de Medicina - Líder
8 resultados
Resultados de Busca
Agora exibindo 1 - 8 de 8
- Molecular Investigation Confirms Myotis Genus Bats as Common Hosts of Polychromophilus in Brazil(2023) MATHIAS, Bruno da Silva; MINOZZO, Guilherme Augusto; BIONDO, Alexander Welker; COSTA, Jaciara de Oliveira Jorge; SOARES, Herbert Sousa; MARCILI, Arlei; GUIMARAES, Lilian de Oliveira; ANJOS, Carolina Clares dos; SANTOS, Andrea Pires Dos; RIEDIGER, Irina Nastassja; FECCHIO, Alan; BUENO, Marina Galvao; PINHO, Joao Batista; KIRCHGATTER, KarinPlasmodium spp. and some other blood parasites belonging to the order Haemosporida are the focus of many epidemiological studies worldwide. However, haemosporidian parasites from wild animals are largely neglected in scientific research. For example, Polychromophilus parasites, which are exclusive to bats, are described in Europe, Asia, Africa, and Oceania, but little is known about their presence and genetic diversity in the New World. In this study, 224 samples of bats from remaining fragments of the Atlantic Forest and Pantanal biomes, as well as urbanized areas in southern and southeastern Brazil, were analyzed for the presence of haemosporidian parasites by PCR of the mitochondrial gene that encodes cytochrome b (cytb). The PCR fragments of the positive samples were sequenced and analyzed by the Bayesian inference method to reconstruct the phylogenetic relationships between Polychromophilus parasites from bats in Brazil and other countries. Sequences from Brazilian lineages of Polychromophilus were recovered in a clade with sequences from Polychromophilus murinus and close to the one Polychromophilus sequence obtained in Panama, the only available sequence for the American continent. This clade was restricted to bats of the family Vespertilionidae and distinct from Polychromophilus melanipherus, a parasite species mainly found in bats of the family Miniopteridae. The detection of Polychromophilus and the genetic proximity to P. murinus were further confirmed with the amplification of two other genes (clpc and asl). We also found a Haemosporida parasite sequence in a sample of Noctilio albiventris collected in the Pantanal biome, which presents phylogenetic proximity with avian Haemoproteus sequences. Morphological and molecular studies are still needed to conclude and describe the Polychromophilus species in Brazilian Myotis bats in more detail and to confirm Haemoproteus parasites in bats. Nevertheless, these molecular results in Brazilian bats confirm the importance of studying these neglected genera.
- First Molecular Detection of Polychromophilus Parasites in Brazilian Bat Species(2021) MINOZZO, Guilherme Augusto; MATHIAS, Bruno da Silva; RIEDIGER, Irina Nastassja; GUIMARAES, Lilian de Oliveira; ANJOS, Carolina Clares dos; MONTEIRO, Eliana Ferreira; SANTOS, Andrea Pires dos; BIONDO, Alexander Welker; KIRCHGATTER, KarinBlood parasites of the Haemosporida order, such as the Plasmodium spp. responsible for malaria, have become the focus of many studies in evolutionary biology. However, there is a lack of molecular investigation of haemosporidian parasites of wildlife, such as the genus Polychromophilus. Species of this neglected genus exclusively have been described in bats, mainly in Europe, Asia, and Africa, but little is known about its presence and genetic diversity on the American continent. Here, we investigated 406 bats from sites inserted in remnant fragments of the Atlantic Forest and Cerrado biomes and urbanized areas from southern Brazil for the presence of Polychromophilus species by PCR of the mitochondrial cytochrome b encoding gene. A total of 1.2% of bats was positive for Polychromophilus, providing the first molecular information of these parasites in Myotis riparius and Eptesicus diminutus, common vespertilionid bats widely distributed in different Brazilian biomes, and Myotis ruber, an endangered species. A Bayesian analysis was conducted to reconstruct the phylogenetic relationships between Polychromophilus recovered from Brazilian bats and those identified elsewhere. Sequences of Brazilian Polychromophilus lineages were placed with P. murinus and in a clade distinct from P. melanipherus, mainly restricted to bats in the family Vespertilionidae. However, the sequences were split into two minor clades, according to the genus of hosts, indicating that P. murinus and a distinct species may be circulating in Brazil. Morphological observations combined with additional molecular studies are needed to conclude and describe these Polychromophilus species.
- The recombinant LIC10508 is a plasma fibronectin, plasminogen, fibrinogen and C4BP-binding protein of Leptospira interrogans(2016) SIQUEIRA, Gabriela H.; TEIXEIRA, Aline F.; FERNANDES, Luis G.; SOUZA, Gisele O. de; KIRCHGATTER, Karin; ROMERO, Eliete C.; VASCONCELLOS, Silvio A.; VIEIRA, Monica L.; NASCIMENTO, Ana Lucia T. O.Leptospirosis is a zoonosis caused by pathogenic Leptospira spp. In this study, we report that the recombinant proteins LIC10507, LIC10508 and LIC10509 are recognized by confirmed leptospirosis serum samples at both phases of the disease. The recombinant rLIC10508 and rLIC10507 are plasminogen (PLG)-binding proteins, capable of generating plasmin in the presence of a PLG activator. The proteins bind to PLG in a dose-dependent and saturable manner, fulfilling host-ligand interaction. Furthermore, rLIC10508 interacts with fibrinogen (Fg), plasma fibronectin and C4b binding protein (C4BP). The binding of rLIC10508 to Fg decreases the fibrin clotting in a thrombin-catalyzed reaction. The incubation with 4 mu M of protein promoted 40% inhibition upon clotting formation. C4BP bound to rLIC10508 retained its cofactor activity for factor I promoting the cleavage of C4b protein, which may reduce the membrane attack complex formation. Although these proteins have high amino acid sequence similarity, rLIC10508 is the most talented of the three, a behavior that might be explained by its unique putative 3D structure, whereas structures of rLIC10507 and rLIC10509 are very similar. Plasmin generation (rLIC10507 and rLIC10508), together with decreasing fibrin clot formation (rLIC10508) and impairment of the complement system (rLIC10508) may help the bacteria to overcome host defense, facilitating the infection process.
- The interaction of two novel putative proteins of Leptospira interrogans with E-cadherin, plasminogen and complement components with potential role in bacterial infection(2019) KOCHI, Leandro T.; V, Luis G. Fernandes; SOUZA, Gisele O.; VASCONCELLOS, Silvio A.; HEINEMANN, Marcos B.; ROMERO, Eliete C.; KIRCHGATTER, Karin; NASCIMENTO, Ana L. T. O.Leptospirosis is a worldwide zoonosis caused by pathogenic species of Leptospira. Leptospires are able to adhere to exposed extracellular matrix in injured tissues and, once in the bloodstream, can survive the attack of the immune system and spread to colonize target organs. In this work, we report that two novel putative proteins, coded by the genes LIC11711 and LIC12587 of L. interrogans serovar Copenhageni are conserved among pathogenic strains, and probably exposed in the bacterial surface. Soluble recombinant proteins were expressed in Escherichia coli, purified and characterized. Both recombinant proteins bound to laminin and E-cadherin, suggesting an initial adhesion function in host epithelial cells. The recombinant protein LIC11711 (rLIC11711) was able to capture plasminogen (PLG) from normal human serum and convert to enzymatically active plasmin (PLA), in the presence of PLG activator. rLIC12587 (recombinant protein LIC12587) displayed a dose dependent and saturable interaction with components C7, C8, and C9 of the complement system, reducing the bactericidal effect of the complement. Binding to C9 may have consequences such as C9 polymerization inhibition, interfering with the membrane attack complex formation. Blocking LIC11711 and LIC12587 on bacterial cells by the respective antiserum reduced leptospiral cell viability when exposed to normal human serum (NHS). Both recombinant proteins could be recognized by serum samples of confirmed leptospirosis, but not of unrelated diseases, suggesting that the native proteins are immunogenic and expressed during leptospirosis. Taken together, our data suggest that these proteins may have a role in leptospiral pathogenesis, participating in immune evasion strategies.
- Avian Malaria and Related Parasites from Resident and Migratory Birds in the Brazilian Atlantic Forest, with Description of a New Haemoproteus Species(2021) ANJOS, Carolina C.; CHAGAS, Carolina R. F.; FECCHIO, Alan; SCHUNCK, Fabio; COSTA-NASCIMENTO, Maria J.; MONTEIRO, Eliana F.; MATHIAS, Bruno S.; BELL, Jeffrey A.; GUIMARAES, Lilian O.; COMICHE, Kiba J. M.; VALKIUNAS, Gediminas; KIRCHGATTER, KarinDetermining the prevalence and local transmission dynamics of parasitic organisms are necessary to understand the ability of parasites to persist in host populations and disperse across regions, yet local transmission dynamics, diversity, and distribution of haemosporidian parasites remain poorly understood. We studied the prevalence, diversity, and distributions of avian haemosporidian parasites of the genera Plasmodium, Haemoproteus, and Leucocytozoon among resident and migratory birds in Serra do Mar, Brazil. Using 399 blood samples from 66 Atlantic Forest bird species, we determined the prevalence and molecular diversity of these pathogens across avian host species and described a new species of Haemoproteus. Our molecular and morphological study also revealed that migratory species were infected more than residents. However, vector infective stages (gametocytes) of Leucocytozoon spp., the most prevalent parasites found in the most abundant migrating host species in Serra do Mar (Elaenia albiceps), were not seen in blood films of local birds suggesting that this long-distance Austral migrant can disperse Leucocytozoon parasite lineages from Patagonia to the Atlantic Forest, but lineage sharing among resident species and local transmission cannot occur in this part of Brazil. Our study demonstrates that migratory species may harbor a higher diversity and prevalence of parasites than resident species, but transportation of some parasites by migratory hosts may not always affect local transmission.
- Naturally Acquired Humoral Immunity against Malaria Parasites in Non-Human Primates from the Brazilian Amazon, Cerrado and Atlantic Forest(2020) MONTEIRO, Eliana Ferreira; FERNANDEZ-BECERRA, Carmen; ARAUJO, Maisa da Silva; MESSIAS, Mariluce Rezende; OZAKI, Luiz Shozo; DUARTE, Ana Maria Ribeiro de Castro; BUENO, Marina Galvao; CATAO-DIAS, Jose Luiz; CHAGAS, Carolina Romeiro Fernandes; MATHIAS, Bruno da Silva; SANTOS, Mayra Gomes dos; SANTOS, Stefanie Vanessa; HOLCMAN, Marcia Moreira; JR, Julio Cesar de Souza; KIRCHGATTER, KarinNon-human primates (NHPs) have been shown to be infected by parasites of the genusPlasmodium, the etiological agent of malaria in humans, creating potential risks of zoonotic transmission.Plasmodium brasilianum, a parasite species similar toP. malariaeof humans, have been described in NHPs from Central and South America, including Brazil. The merozoite surface protein 1 (MSP1), besides being a malaria vaccine candidate, is highly immunogenic. Due to such properties, we tested this protein for the diagnosis of parasite infection. We used recombinant proteins ofP. malariaeMSP1, as well as ofP. falciparumandP. vivax, for the detection of antibodies anti-MSP1 of these parasite species, in the sera of NHPs collected in different regions of Brazil. About 40% of the NHP sera were confirmed as reactive to the proteins of one or more parasite species. A relatively higher number of reactive sera was found in animals from the Atlantic Forest than those from the Amazon region, possibly reflecting the former more intense parasite circulation among NHPs due to their proximity to humans at a higher populational density. The presence ofPlasmodiumpositive NHPs in the surveyed areas, being therefore potential parasite reservoirs, needs to be considered in any malaria surveillance program.
- Antibody Profile Comparison against MSP1 Antigens of Multiple Plasmodium Species in Human Serum Samples from Two Different Brazilian Populations Using a Multiplex Serological Assay(2021) MONTEIRO, Eliana Ferreira; FERNANDEZ-BECERRA, Carmen; CURADO, Izilda; WUNDERLICH, Gerhard; HIYANE, Meire Ioshie; KIRCHGATTER, KarinPlasmodium malariae has a wide geographic distribution, but mainly at very low parasitemias and in co-infections, leading to an underestimated prevalence of this species. Studies for the detection of antibodies against Plasmodium recombinant proteins are increasingly used to map geographical distributions, seroprevalence and transmission intensities of malaria infection. However, no seroepidemiological survey using recombinant P. malariae proteins has been conducted in Brazil. This work evaluated the antibody response in serum samples of individuals from endemic regions of Brazil (the Amazon region and Atlantic Forest) against five recombinant proteins of P. malariae merozoite surface protein 1 (MSP1), and the MSP1 C-terminal portions of P. vivax and P. falciparum, in a multiplex assay. The positivity was 69.5% of samples recognizing at least one MSP1 recombinant protein. The mean of the Reactivity Index for the C-terminal portion of the P. falciparum was significantly higher compared to the other recombinant proteins, followed by the C-terminal of P. vivax and the N-terminal of P. malariae. Among the recombinant P. malariae proteins, the N-terminal of P. malariae showed the highest Reactivity Index alone. This study validates the use of the multiplex assay to measure naturally acquired IgG antibodies against Plasmodium MSP1 proteins and demonstrate that these proteins are important tools for seroepidemiological surveys and could be used in malaria surveillance.
- Heparin-Binding Protein Release Is Strongly Induced by Leptospira Species and Is a Candidate for an Early Diagnostic Marker of Human Leptospirosis(2019) VIEIRA, Monica L.; PERSSON, Sandra; LOPES-FERREIRA, Monica; ROMERO, Eliete C.; KIRCHGATTER, Karin; NASCIMENTO, Ana Lucia T. O.; HERWALD, HeikoHere we show that heparin-binding protein (HBP) can be used as an early biomarker in patients with leptospirosis. Our experiments further suggest that leptospiral proteins are able to release HBP to an extent that the vascular barrier is impaired.Leptospirosis, caused by spirochetes of the genus Leptospira, is one of the most widespread zoonoses worldwide. Efficient diagnostic methods for early diagnosis of leptospirosis are still lacking, and acute disease presents with nonspecific symptomatology and is often misdiagnosed. The leptospires pathogenic processes and virulence mechanisms remain virtually unknown. In severe infections, hemostatic impairment is frequently observed, and pathophysiological complications often develop when the host response is modulated by the pathogen. The neutrophil heparin-binding protein (HBP) is an inflammatory mediator and potent inducer of vascular leakage. In this study, we found that leptospires and their secreted products induce the release of HBP from stimulated neutrophils through a controlled degranulation mechanism. We acknowledged 2 leptospiral proteins as able to induce HBP degranulation. These findings have clinical implications, as high levels of HBP were detected in serum from patients with leptospirosis, especially at the early phase of the disease. In conclusion, we describe a new mechanism by which the leptospirosis pathophysiological complications may arise, such as vascular leakage and edema formation. We also propose HBP as a new early screening biomarker for human leptospirosis.