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An insight into the sialome of Simulium guianense (DIPTERA:SIMulIIDAE), the main vector of River Blindness Disease in Brazil.

Chagas AC, Calvo E, Pimenta PF, Ribeiro JM - BMC Genomics (2011)

Bottom Line: Insect-specific families were also found.About 63.4% of all secreted products revealed protein families found only in Simulium.Additionally, we found a novel peptide similar to kunitoxin with a structure distantly related to serine protease inhibitors.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, 12735 Twinbrook Parkway, National Institutes of Health, Rockville, Maryland 20892-8132, USA.

ABSTRACT

Background: Little is known about the composition and function of the saliva in black flies such as Simulium guianense, the main vector of river blindness disease in Brazil. The complex salivary potion of hematophagous arthropods counteracts their host's hemostasis, inflammation, and immunity.

Results: Transcriptome analysis revealed ubiquitous salivary protein families--such as the Antigen-5, Yellow, Kunitz domain, and serine proteases--in the S. guianense sialotranscriptome. Insect-specific families were also found. About 63.4% of all secreted products revealed protein families found only in Simulium. Additionally, we found a novel peptide similar to kunitoxin with a structure distantly related to serine protease inhibitors. This study revealed a relative increase of transcripts of the SVEP protein family when compared with Simulium vittatum and S. nigrimanum sialotranscriptomes. We were able to extract coding sequences from 164 proteins associated with blood and sugar feeding, the majority of which were confirmed by proteome analysis.

Conclusions: Our results contribute to understanding the role of Simulium saliva in transmission of Onchocerca volvulus and evolution of salivary proteins in black flies. It also consists of a platform for mining novel anti-hemostatic compounds, vaccine candidates against filariasis, and immuno-epidemiologic markers of vector exposure.

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The amylase/maltase family in Diptera. Phylogram derived from the alignment of two Simulium guianense proteins (indicated by a square and starting with "Sg-"), with their best matches in the non-redundant protein database of the National Center for Biotechnology Information identified by the three first letters of the genus name, followed by the three first letters of their species name, followed by their NCBI accession numbers. Glycosidases from Simulium vittatum and Simulium nigrimanum are indicated by a triangle and a circle, respectively. The numbers on the tree bifurcations indicate the percentage bootstrap support above 75%. The bar at the bottom represents 10% amino acid substitution. Protein sequences were aligned by the Clustal program, and the dendogram was made with the Mega package after 10 000 bootstraps with the neighbor-joining algorithm.
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Figure 3: The amylase/maltase family in Diptera. Phylogram derived from the alignment of two Simulium guianense proteins (indicated by a square and starting with "Sg-"), with their best matches in the non-redundant protein database of the National Center for Biotechnology Information identified by the three first letters of the genus name, followed by the three first letters of their species name, followed by their NCBI accession numbers. Glycosidases from Simulium vittatum and Simulium nigrimanum are indicated by a triangle and a circle, respectively. The numbers on the tree bifurcations indicate the percentage bootstrap support above 75%. The bar at the bottom represents 10% amino acid substitution. Protein sequences were aligned by the Clustal program, and the dendogram was made with the Mega package after 10 000 bootstraps with the neighbor-joining algorithm.

Mentions: "Amylases and maltases are ubiquitous enzymes that help digestion of carbohydrates and are commonly found in sialotrancriptomes from Nematocera including mosquitoes, biting midges, sand flies, and black flies [67]. These enzymes can be recognized by the KOG motif 0471, named Alpha-amylase." The proteome of the mosquito An. gambiae has 17 members of this family, one of which (AGAP002102) is expressed in the SGs [64]. The proteome of Ae. aegypti contains 24 such enzymes, at least two of which are expressed in their SGs [25] while Culex quinquefasciatus has 35 such enzymes, with two also expressed in their SGs [68]. Additional File 2 presents two truncated gene products coding for glycosidases (Sg-214 and Sg-296). Glycosidases of S. guianense have 79% sequence identity to other described black fly enzymes (blastp comparisons can be seen in Additional File 2). Phylogenetic analysis of the S. guianense protein sequences together with their closest BLAST matches against the NR database indicates that the two S. guianense proteins group into different clades with strong bootstrap support (Figure 3). Sg-296 groups to other Simulium enzymes, to a salivary sand fly enzyme, and to drosophilids, as indicated by clade I (Figure 3). Sg-214, on the other hand, groups with a second set of Simulium enzymes and, with 76% bootstrap support, to Culicine mosquitoes and salivary biting midge enzymes,[34,69] as shown by clade II (Figure 3). Notice that the mosquitoes, black flies, and Culicoides sequences each group within subclades having strong bootstrap support, as expected. A third clade of mosquito-only enzymes (including anophelines and culicines) is also obtained, which merges without strong bootstrap support to Clade II. Interestingly, the mosquito enzymes in both clades II and III have all been previously described in salivary transcriptomes, suggesting a common origin of these sugar-hydrolyzing enzymes in the ancestral fly originating mosquitoes, black flies, and biting midges. These results indicate that the two S. guianense sequences appear to be a product of ancient gene duplication, Sg-296 from Clade I being the most ancient, as it groups with enzymes of Brachycera, while the two salivary gene products from Culicine mosquitoes appear to derive from a gene duplication after the split of the Culicidae. The sequences of the glycosidases Sg-214 and Sg-296 found in the sialotranscriptome of S. guianense were confirmed by proteome analysis within the fractions 16 and 17, respectively, just above the 49-kDa standard (Figure 2 and Table 4).


An insight into the sialome of Simulium guianense (DIPTERA:SIMulIIDAE), the main vector of River Blindness Disease in Brazil.

Chagas AC, Calvo E, Pimenta PF, Ribeiro JM - BMC Genomics (2011)

The amylase/maltase family in Diptera. Phylogram derived from the alignment of two Simulium guianense proteins (indicated by a square and starting with "Sg-"), with their best matches in the non-redundant protein database of the National Center for Biotechnology Information identified by the three first letters of the genus name, followed by the three first letters of their species name, followed by their NCBI accession numbers. Glycosidases from Simulium vittatum and Simulium nigrimanum are indicated by a triangle and a circle, respectively. The numbers on the tree bifurcations indicate the percentage bootstrap support above 75%. The bar at the bottom represents 10% amino acid substitution. Protein sequences were aligned by the Clustal program, and the dendogram was made with the Mega package after 10 000 bootstraps with the neighbor-joining algorithm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3285218&req=5

Figure 3: The amylase/maltase family in Diptera. Phylogram derived from the alignment of two Simulium guianense proteins (indicated by a square and starting with "Sg-"), with their best matches in the non-redundant protein database of the National Center for Biotechnology Information identified by the three first letters of the genus name, followed by the three first letters of their species name, followed by their NCBI accession numbers. Glycosidases from Simulium vittatum and Simulium nigrimanum are indicated by a triangle and a circle, respectively. The numbers on the tree bifurcations indicate the percentage bootstrap support above 75%. The bar at the bottom represents 10% amino acid substitution. Protein sequences were aligned by the Clustal program, and the dendogram was made with the Mega package after 10 000 bootstraps with the neighbor-joining algorithm.
Mentions: "Amylases and maltases are ubiquitous enzymes that help digestion of carbohydrates and are commonly found in sialotrancriptomes from Nematocera including mosquitoes, biting midges, sand flies, and black flies [67]. These enzymes can be recognized by the KOG motif 0471, named Alpha-amylase." The proteome of the mosquito An. gambiae has 17 members of this family, one of which (AGAP002102) is expressed in the SGs [64]. The proteome of Ae. aegypti contains 24 such enzymes, at least two of which are expressed in their SGs [25] while Culex quinquefasciatus has 35 such enzymes, with two also expressed in their SGs [68]. Additional File 2 presents two truncated gene products coding for glycosidases (Sg-214 and Sg-296). Glycosidases of S. guianense have 79% sequence identity to other described black fly enzymes (blastp comparisons can be seen in Additional File 2). Phylogenetic analysis of the S. guianense protein sequences together with their closest BLAST matches against the NR database indicates that the two S. guianense proteins group into different clades with strong bootstrap support (Figure 3). Sg-296 groups to other Simulium enzymes, to a salivary sand fly enzyme, and to drosophilids, as indicated by clade I (Figure 3). Sg-214, on the other hand, groups with a second set of Simulium enzymes and, with 76% bootstrap support, to Culicine mosquitoes and salivary biting midge enzymes,[34,69] as shown by clade II (Figure 3). Notice that the mosquitoes, black flies, and Culicoides sequences each group within subclades having strong bootstrap support, as expected. A third clade of mosquito-only enzymes (including anophelines and culicines) is also obtained, which merges without strong bootstrap support to Clade II. Interestingly, the mosquito enzymes in both clades II and III have all been previously described in salivary transcriptomes, suggesting a common origin of these sugar-hydrolyzing enzymes in the ancestral fly originating mosquitoes, black flies, and biting midges. These results indicate that the two S. guianense sequences appear to be a product of ancient gene duplication, Sg-296 from Clade I being the most ancient, as it groups with enzymes of Brachycera, while the two salivary gene products from Culicine mosquitoes appear to derive from a gene duplication after the split of the Culicidae. The sequences of the glycosidases Sg-214 and Sg-296 found in the sialotranscriptome of S. guianense were confirmed by proteome analysis within the fractions 16 and 17, respectively, just above the 49-kDa standard (Figure 2 and Table 4).

Bottom Line: Insect-specific families were also found.About 63.4% of all secreted products revealed protein families found only in Simulium.Additionally, we found a novel peptide similar to kunitoxin with a structure distantly related to serine protease inhibitors.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, 12735 Twinbrook Parkway, National Institutes of Health, Rockville, Maryland 20892-8132, USA.

ABSTRACT

Background: Little is known about the composition and function of the saliva in black flies such as Simulium guianense, the main vector of river blindness disease in Brazil. The complex salivary potion of hematophagous arthropods counteracts their host's hemostasis, inflammation, and immunity.

Results: Transcriptome analysis revealed ubiquitous salivary protein families--such as the Antigen-5, Yellow, Kunitz domain, and serine proteases--in the S. guianense sialotranscriptome. Insect-specific families were also found. About 63.4% of all secreted products revealed protein families found only in Simulium. Additionally, we found a novel peptide similar to kunitoxin with a structure distantly related to serine protease inhibitors. This study revealed a relative increase of transcripts of the SVEP protein family when compared with Simulium vittatum and S. nigrimanum sialotranscriptomes. We were able to extract coding sequences from 164 proteins associated with blood and sugar feeding, the majority of which were confirmed by proteome analysis.

Conclusions: Our results contribute to understanding the role of Simulium saliva in transmission of Onchocerca volvulus and evolution of salivary proteins in black flies. It also consists of a platform for mining novel anti-hemostatic compounds, vaccine candidates against filariasis, and immuno-epidemiologic markers of vector exposure.

Show MeSH
Related in: MedlinePlus