Characterization of Vitellin and Quantification of Vitellogenin in Amblyomma americanum (Acari: Ixodidae)
Abstract
Vitellin from Amblyomma americanum is a hemoglycolipophosphoprotein as shown by specific staining of polyacrylamide gels, carbohydrate and lipid analyses. The molecular weight was determined by gel permeation chromatography to be 360 kDa. Under reducing conditions (SDS-PAGE), the vitellin had 6 major polypeptides ranging from 70-210 kDa. The absorption maxima for the vitellin was 280 and 400 nm which is indicative of a protein containing heme. The predominant carbohydrates detected in A. americanum vitellin were mannose and N-acetylglucosamine as determined by gas chromatography. The neutral lipids detected in A. americanum vitellin were cholesterol, cholesteryl esters, fatty acids, triacylglycerides and diacylglycerides. The phospholipids associated with A. americanum were L-alpha-phosphatidylethanolamine and phosphatidylcholine. Amino acid analysis showed that the vitellin was rich in histidine, glutamic acid, valine, glycine and leucine, but threonine and tryosine concentrations were low.
