Molecular characterization and expression analysis of annexin B3 and B38 as secretory proteins in Echinococcus granulosus

Abstract Background Cystic echinococcosis is a parasitic zoonotic disease, which poses a threat to public health and animal husbandry, and causes significant economic losses. Annexins are a family of phospholipid-binding proteins with calcium ion-binding activity, which have many functions. Methods Two annexin protein family genes [Echinococcus granulosus annexin B3 (EgAnxB3) and EgAnxB38] were cloned and molecularly characterized using bioinformatic analysis. The immunoreactivity of recombinant EgAnxB3 (rEgAnxB3) and rEgAnxB38 was investigated using western blotting. The distribution of EgAnxB3 and EgAnxB38 in protoscoleces (PSCs), the germinal layer, 18-day strobilated worms and 45-day adult worms was analyzed by immunofluorescence localization, and their secretory characteristics were analyzed preliminarily; in addition, quantitative real-time reverse transcription polymerase chain reaction was used to analyze their transcript levels in PSCs and 28-day strobilated worms stages. The phospholipid-binding activities of rEgAnxB3 and rEgAnxB38 were also analyzed. Results EgAnxB3 and EgAnxB38 are conserved and contain calcium-binding sites. Both rEgAnxB3 and rEgAnxB38 could be specifically recognized by the serum samples from E. granulosus-infected sheep, indicating that they had strong immunoreactivity. EgAnxB3 and EgAnxB38 were distributed in all stages of E. granulosus, and their transcript levels were high in the 28-day strobilated worms. They were found in liver tissues near the cysts. In addition, rEgAnxB3 has Ca2+-dependent phospholipid-binding properties. Conclusions EgAnxB3 and EgAnxB38 contain calcium-binding sites, and rEgAnxB3 has Ca2+-dependent phospholipid-binding properties. EgAnxB3 and EgAnxB38 were transcribed in PSCs and 28-day strobilated worms. They were expressed in all stages of E. granulosus, and distributed in the liver tissues near the hydatid cyst, indicating that they are secreted proteins that play a crucial role in the development of E. granulosus.

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Molecular Characterization and Expression Analysis of Annexin B3 and B38 as Secretory Proteins in Echinococcus Granulosus

10.21203/rs.3.rs-112153/v1 ◽

2020 ◽

Author(s):

Hongyu Song ◽

Xue He ◽

Xiaodi Du ◽

Ruiqi Hua ◽

Jing Xu ◽

...

Keyword(s):

Echinococcus Granulosus ◽

Binding Sites ◽

Calcium Binding ◽

Economic Losses ◽

Binding Properties ◽

Transcript Levels ◽

Phospholipid Binding ◽

Calcium Binding Sites ◽

Strong Immunoreactivity ◽

Liver Tissues

Abstract Background: Cystic Echinococcosis is a parasitic zoonotic disease, which poses a threat to public health and animal husbandry, and causes significant economic losses. Annexin is a kind of phospholipid binding protein with calcium ion binding activity, which has many functions.Methods: Two annexin protein family genes (EgAnxB3 and EgAnxB38) were cloned and molecular characterized using bioinformatic analysis. The immunoreactivity of rEgAnxB3 and rEgAnxB38 was investigated using western blotting. The distribution and transcript levels of EgAnxB3 and EgAnxB38 in different developmental stages of Echinococcus granulosus were analyzed by immunofluorescence localization and quantitative real-time reverse transcription PCR, and their secretory characteristics were analyzed preliminary. The phospholipid-binding activities of rEgAnxB3 and rEgAnxB38 were also tested.Results: EgAnxB3 and EgAnxB38 are conserved and contain calcium binding sites. Both rEgAnxB3 and rEgAnxB38 could be specifically recognized by the serum samples from E. granulosus-infected sheep, which have strong immunoreactivity. EgAnxB3 and EgAnxB38 were distributed in all stages of E. granulosus and had high transcript levels in the 28-day strobilated worms. They were found in liver tissues near the cysts. In addition, rEgAnxB3 had Ca2+-dependent phospholipid-binding properties.Conclusions: EgAnxB3 and EgAnxB38 contained calcium-binding sites, and rEgAnxB3 had Ca2+-dependent phospholipid-binding properties. rEgAnxB3 and rEgAnxB38 had strong immunoreactivity. EgAnxB3 and EgAnxB38 were transcribed in PSCs and worms. They were expressed in all stages of E. granulosus, and distributed in the liver tissues near the hydatid cyst, indicating that EgAnxB3 and EgAnxB38 are secreted proteins that play an crucial role in the development of E. granulosus.

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Properties of the non-specific calcium-binding sites of rabbit skeletal-muscle myosin

Biochemical Journal ◽

10.1042/bj1850265 ◽

1980 ◽

Vol 185 (1) ◽

pp. 265-268 ◽

Cited By ~ 10

Author(s):

J Wikman-Coffelt

Keyword(s):

Skeletal Muscle ◽

Light Chain ◽

Binding Sites ◽

Calcium Binding ◽

Light Chains ◽

Binding Properties ◽

Skeletal Muscle Myosin ◽

Heavy Chains ◽

Calcium Binding Sites ◽

Muscle Myosin

The non-specific Ca2+-binding sites of skeletal-muscle myosin are located on the light chains; with the dissociation of light chains there is a corresponding decrease in the number of Ca2+-binding sites on light-chain-deficient myosin. The released light chains have a decreased binding affinity. Myosin heavy chains indirectly influence the Ca2+-binding properties of light chains by increasing the affinity of light chains for bivalent cations; this influence varies with pH. Because of light-chain dissociation at low Ca2+ and/or Mg2+ concentrations, anomalies may exist when analyses of non-specific Ca2+-binding properties of myosin are assessed by dialysis equilibrium.

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