An insight into the sialome of the oriental rat flea, Xenopsylla cheopis (Rots).
BACKGROUND
The salivary glands of hematophagous animals contain a complex cocktail that interferes with the host hemostasis and inflammation pathways, thus increasing feeding success. Fleas represent a relatively recent group of insects that evolved hematophagy independently of other insect orders.


RESULTS
Analysis of the salivary transcriptome of the flea Xenopsylla cheopis, the vector of human plague, indicates that gene duplication events have led to a large expansion of a family of acidic phosphatases that are probably inactive, and to the expansion of the FS family of peptides that are unique to fleas. Several other unique polypeptides were also uncovered. Additionally, an apyrase-coding transcript of the CD39 family appears as the candidate for the salivary nucleotide hydrolysing activity in X.cheopis, the first time this family of proteins is found in any arthropod salivary transcriptome.


CONCLUSIONS
Analysis of the salivary transcriptome of the flea X. cheopis revealed the unique pathways taken in the evolution of the salivary cocktail of fleas. Gene duplication events appear as an important driving force in the creation of salivary cocktails of blood feeding arthropods, as was observed with ticks and mosquitoes. Only five other flea salivary sequences exist at this time at NCBI, all from the cat flea C. felis. This work accordingly represents the only relatively extensive sialome description of any flea species. Sialotranscriptomes of additional flea genera will reveal the extent that these novel polypeptide families are common throughout the Siphonaptera.
Andersen
John F
JF
Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. jandersen@niaid.nih.gov <jandersen@niaid.nih.gov>
Hinnebusch
B Joseph
BJ
Lucas
David A
DA
Conrads
Thomas P
TP
Veenstra
Timothy D
TD
Pham
Van M
VM
Ribeiro
José M C
JM
D000595:Amino Acid Sequence; D000818:Animals; D001081:Apyrase / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D002415:Cats; D006801:Humans; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D010802:Phylogeny; D020543:Proteome / Q000235:genetics; D051381:Rats; D012376:Rodent Diseases / Q000469:parasitology; D012463:Saliva / Q000737:chemistry / Q000201:enzymology*; D012469:Salivary Glands / Q000378:metabolism; D016415:Sequence Alignment; D005423:Siphonaptera / Q000502:physiology*; D012984:Software; D053719:Tandem Mass Spectrometry
D020543:Proteome; D010744:Phosphoric Monoester Hydrolases; D001081:Apyrase