Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
Add more filters










Database
Language
Publication year range
1.
BMC Genomics ; 15: 943, 2014 Oct 29.
Article in English | MEDLINE | ID: mdl-25351875

ABSTRACT

BACKGROUND: The fungal genus Sporothrix includes at least four human pathogenic species. One of these species, S. brasiliensis, is the causal agent of a major ongoing zoonotic outbreak of sporotrichosis in Brazil. Elsewhere, sapronoses are caused by S. schenckii and S. globosa. The major aims on this comparative genomic study are: 1) to explore the presence of virulence factors in S. schenckii and S. brasiliensis; 2) to compare S. brasiliensis, which is cat-transmitted and infects both humans and cats with S. schenckii, mainly a human pathogen; 3) to compare these two species to other human pathogens (Onygenales) with similar thermo-dimorphic behavior and to other plant-associated Sordariomycetes. RESULTS: The genomes of S. schenckii and S. brasiliensis were pyrosequenced to 17x and 20x coverage comprising a total of 32.3 Mb and 33.2 Mb, respectively. Pair-wise genome alignments revealed that the two species are highly syntenic showing 97.5% average sequence identity. Phylogenomic analysis reveals that both species diverged about 3.8-4.9 MYA suggesting a recent event of speciation. Transposable elements comprise respectively 0.34% and 0.62% of the S. schenckii and S. brasiliensis genomes and expansions of Gypsy-like elements was observed reflecting the accumulation of repetitive elements in the S. brasiliensis genome. Mitochondrial genomic comparisons showed the presence of group-I intron encoding homing endonucleases (HE's) exclusively in S. brasiliensis. Analysis of protein family expansions and contractions in the Sporothrix lineage revealed expansion of LysM domain-containing proteins, small GTPases, PKS type1 and leucin-rich proteins. In contrast, a lack of polysaccharide lyase genes that are associated with decay of plants was observed when compared to other Sordariomycetes and dimorphic fungal pathogens, suggesting evolutionary adaptations from a plant pathogenic or saprobic to an animal pathogenic life style. CONCLUSIONS: Comparative genomic data suggest a unique ecological shift in the Sporothrix lineage from plant-association to mammalian parasitism, which contributes to the understanding of how environmental interactions may shape fungal virulence. . Moreover, the striking differences found in comparison with other dimorphic fungi revealed that dimorphism in these close relatives of plant-associated Sordariomycetes is a case of convergent evolution, stressing the importance of this morphogenetic change in fungal pathogenesis.


Subject(s)
Cat Diseases/microbiology , Fungal Proteins/genetics , Sporothrix/genetics , Sporotrichosis/transmission , Virulence Factors/genetics , Adaptation, Biological , Animals , Cat Diseases/transmission , Cats , Evolution, Molecular , Genetic Speciation , Genome, Mitochondrial , Humans , Phylogeny , Sporothrix/classification , Sporothrix/pathogenicity , Sporotrichosis/microbiology , Sporotrichosis/veterinary
2.
Infect Immun ; 78(4): 1552-63, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20145100

ABSTRACT

Hookworm glutathione S-transferases (GSTs) are critical for parasite blood feeding and survival and represent potential targets for vaccination. Three cDNAs, each encoding a full-length GST protein from the human hookworm Necator americanus (and designated Na-GST-1, Na-GST-2, and Na-GST-3, respectively) were isolated from cDNA based on their sequence similarity to Ac-GST-1, a GST from the dog hookworm Ancylostoma caninum. The open reading frames of the three N. americanus GSTs each contain 206 amino acids with 51% to 69% sequence identity between each other and Ac-GST-1. Sequence alignment with GSTs from other organisms shows that the three Na-GSTs belong to a nematode-specific nu-class GST family. All three Na-GSTs, when expressed in Pichia pastoris, exhibited low lipid peroxidase and glutathione-conjugating enzymatic activities but high heme-binding capacities, and they may be involved in the detoxification and/or transport of heme. In two separate vaccine trials, recombinant Na-GST-1 formulated with Alhydrogel elicited 32 and 39% reductions in adult hookworm burdens (P < 0.05) following N. americanus larval challenge relative to the results for a group immunized with Alhydrogel alone. In contrast, no protection was observed in vaccine trials with Na-GST-2 or Na-GST-3. On the basis of these and other preclinical data, Na-GST-1 is under possible consideration for further vaccine development.


Subject(s)
Antigens, Helminth/immunology , Antigens, Helminth/metabolism , Glutathione Transferase/immunology , Glutathione Transferase/metabolism , Heme/metabolism , Necator americanus/enzymology , Necator americanus/immunology , Necatoriasis/prevention & control , Adjuvants, Immunologic/administration & dosage , Aluminum Hydroxide/administration & dosage , Amino Acid Sequence , Animals , Antigens, Helminth/genetics , Cloning, Molecular , Cricetinae , DNA, Complementary/genetics , DNA, Complementary/isolation & purification , DNA, Helminth/genetics , DNA, Helminth/isolation & purification , Gene Expression , Glutathione/metabolism , Glutathione Transferase/genetics , Humans , Lipid Peroxidation , Molecular Sequence Data , Necator americanus/genetics , Necatoriasis/immunology , Open Reading Frames , Pichia/genetics , Recombinant Proteins/genetics , Recombinant Proteins/immunology , Recombinant Proteins/metabolism , Sequence Alignment , Sequence Homology, Amino Acid , Vaccines, Subunit/immunology
3.
J Thromb Thrombolysis ; 29(4): 387-94, 2010 May.
Article in English | MEDLINE | ID: mdl-19705256

ABSTRACT

Sepsis is a systemic response to an infection that leads to a generalized inflammatory reaction. There is an intimate relationship between procoagulant and proinflammatory activities, and coagulation abnormalities are common in septic patients. Pharmaceutical studies have focused to the development of substances that act on coagulation abnormalities and on the link between coagulation and inflammation. Fructose-1,6-bisphosphate (FBP) is a high-energy glycolitic metabolite that in the past two decades has been shown therapeutic effects in great number of pathological situations, including sepsis. The aims of this study were to assess the effects of FBP on platelet aggregation in vitro and ex vivo in healthy and septic rats and evaluate the use of FBP as a treatment for thrombocytopenia and coagulation abnormalities in abdominal sepsis in rat. FBP inhibited platelet aggregation (P < 0.001) in vitro in healthy rats from the smallest dose tested, 2.5 mM, in a dose-dependent manner. The mean effective dose calculated was 10.6 mM. The highest dose tested, 40 mM, completely inhibited platelet aggregation (P < 0.001) induced by ADP. Platelet aggregation in plasma from septic rats was inhibited only with higher doses of FBP, starting from 20 mM (P < 0.001). The calculated mean effective dose was 19.3 mM. Ex vivo platelet aggregation in septic rats was significantly lower (P < 0.05) than healthy rats and the treatment with FBP, at the dose of 2 g/kg, diminished the platelet aggregation at the extension of 27% (P < 0.001), suggesting that FBP is a potent platelet aggregation inhibitor in vivo. Moreover, treatment with FBP 2 g/kg prevented thrombocytopenia (P < 0.001), prolongation of prothrombin and partial thromboplastin time (P < 0.001), but not fibrinogen, in septic rats. The most important findings in this study are that FBP is a potent platelet aggregation inhibitor, in vitro and ex vivo. It presents protective effects on coagulation abnormalities, which can represent a treatment against DIC. The mechanisms for these effects remain under investigation.


Subject(s)
Adenosine Diphosphate/pharmacology , Blood Platelets/metabolism , Fructosediphosphates/pharmacology , Platelet Aggregation Inhibitors/pharmacology , Platelet Aggregation/drug effects , Sepsis/drug therapy , Animals , Blood Coagulation Disorders/drug therapy , Blood Coagulation Disorders/metabolism , Blood Platelets/pathology , Dose-Response Relationship, Drug , Humans , Immunologic Factors/pharmacology , Male , Partial Thromboplastin Time , Prothrombin Time , Rats , Rats, Wistar , Sepsis/metabolism , Thrombocytopenia/drug therapy , Thrombocytopenia/metabolism
4.
FASEB J ; 23(9): 3007-19, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19380510

ABSTRACT

Hookworms digest hemoglobin from erythrocytes via a proteolytic cascade that begins with the aspartic protease, APR-1. Ac-APR-1 from the dog hookworm, Ancylostoma caninum, protects dogs against hookworm infection via antibodies that neutralize enzymatic activity and interrupt blood-feeding. Toward developing a human hookworm vaccine, we expressed both wild-type (Na-APR-1(wt)) and mutant (Na-APR-1(mut)-mutagenesis of the catalytic aspartic acids) forms of Na-APR-1 from the human hookworm, Necator americanus. Refolded Na-APR-1(wt) was catalytically active, and Na-APR-1(mut) was catalytically inactive but still bound substrates. Vaccination of canines with Na-APR-1(mut) and heterologous challenge with A. caninum resulted in significantly reduced parasite egg burdens (P=0.034) and weight loss (P=0.022). Vaccinated dogs also had less gut pathology, fewer adult worms, and reduced blood loss compared to controls but these did not reach statistical significance. Vaccination with Na-APR-1(mut) induced antibodies that bound the native enzyme in the parasite gut and neutralized enzymatic activity of Na-APR-1(wt) and APR-1 orthologues from three other hookworm species that infect humans. IgG1 against Na-APR-1(mut) was the most prominently detected antibody in sera from people resident in high-transmission areas for N. americanus, indicating that natural boosting may occur in exposed humans. Na-APR-1(mut) is now a lead antigen for the development of an antihematophagy vaccine for human hookworm disease.


Subject(s)
Antibodies, Helminth/therapeutic use , Cysteine Endopeptidases/immunology , Hookworm Infections/prevention & control , Necator americanus/immunology , Ancylostomatoidea/immunology , Animals , Antibodies, Helminth/administration & dosage , Dogs , Hookworm Infections/therapy , Humans , Intestines/parasitology , Treatment Outcome , Vaccination/methods , Vaccines/pharmacology , Vaccines/therapeutic use , Weight Loss
SELECTION OF CITATIONS
SEARCH DETAIL
...