Purification and properties of vitellogenin and vitellin from a tick,Ornithodoros moubata

Chinzei, Yasuo; Chino, Haruo; Takahashi, K.

doi:10.1007/bf00689722

Cited by 69 publications

(48 citation statements)

References 26 publications

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“…Identical activation rates at pH 3.5 were observed when activity residues per 1000 amino acids are given [18], or about 270 tyrosinc residues per molecule of vitellin. Active site concentration was estimated by titration with E-64.…”

Section: Characterization Of the Proteinase Activitymentioning

confidence: 80%

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Yolk degradation in tick eggs: I. Occurrence of a cathepsin L‐like acid proteinase in yolk spheres

Fagotto

1990

Arch Insect Biochem Physiol

104

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In crude extracts of eggs of the soft tick Ornithodoros moubata, maximum degradation of vitellin is at pH 3-3.5, whereas no proteolysis is detected at neutral or weakly acidic pHs. Acidic proteolysis is maintained at high level throughout embryonic development, and rapidly decreases in the larva, during the high phase of yolk degradation. Proteinase, acid phosphatase, and N-acetylglucosaminidase are localized within the yolk spheres; these can be considered as lysosomal-like organelles containing both substrate (vitellin) and the degradative machinery. Proteolytic activity has been essentially attributed to a cathepsin L-like enzyme through substrate specificity and inhibitors. The molecular weight is 37,000 to 39,000 as shown using gelatin-containing SDS-PAGE activity gels. At neutral pH the enzyme binds to vitellin, as demonstrated by gel filtration and PAGE under nondenaturing conditions. Acid proteinase activity at pH 5-6 is undetectable both with proteins and synthetic substrates, but is strongly increased after preincubation at pH 3-4. Activation at low pH could be important in the regulation of yolk degradation.

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Section: Characterization Of the Proteinase Activitymentioning

confidence: 80%

“…-E : Table 2 uring absorbance at 400 nm [18]. About 80% of the vitellin was in the supernatant of the first centrifugation and the rest was recovered on the top of the Percoll gradient.…”

Section: V)mentioning

confidence: 99%

Yolk degradation in tick eggs: I. Occurrence of a cathepsin L‐like acid proteinase in yolk spheres

Fagotto

1990

Arch Insect Biochem Physiol

104

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“…Authors described this Vg synthesis cascade induced by hemolymph amino acid as an amino acid signaling (Hansen et al 2004;Attardo et al 2005). Vg is also synthesized by the tick fat body after female adults obtain a blood meal, released into the hemolymph, and then transported and incorporated into eggs as vitellin (Chinzei et al 1983;Chinzei and Yano 1985;Chinzei and Taylor 1990;Taylor et al 1991;Rosell and Coons 1992;James and Oliver 1996;Taylor and Chinzei 2002;Friesen and Reuben Kaufman 2002;Gudderra et al 2002). Because amino acids in the tick are also as important as in the mosquito for Vg synthesis and oocyte development (vitellogenesis), the phenotypic changes, including reduced ability of egg production, in HlLAP RNAi ticks may be due to a reduction, not ablation (because of the existence of other aminopeptidase activity; see Fig.…”

Section: Discussionmentioning

confidence: 98%

RNA interference of cytosolic leucine aminopeptidase reduces fecundity in the hard tick, Haemaphysalis longicornis

et al. 2006

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Ticks are effective vectors of pathogens because of their blood feeding and high fecundity. This high fecundity is related to the size of the blood meal. Therefore, knowledge of how blood proteins are degraded and converted to proteins, including yolk protein, is important for the development of ways to inhibit the utilization of blood proteins by ticks. RNA interference (RNAi) is becoming a powerful post-transcriptional gene silencing technique that provides insight into gene function. We constructed a double-stranded RNA (dsRNA) based on a previously cloned Haemaphysalis longicornis leucine aminopeptidase (HlLAP) gene to reevaluate the biological role in tick blood digestion. Gene specific transcriptional, translational, and functional disruptions were achieved by the introduction of dsRNA into the ticks. Significantly delayed onset of egg-laying and reduced egg oviposition resulted from the RNAi for the HlLAP gene. These results suggest that HlLAP actually works as a blood digestive enzyme and affects tick fecundity via unknown mechanisms. The reduction of egg oviposition may be caused by a decrease in nutrients, especially free amino acids generated by HlLAP, from the blood meal. This is the first report of an impact on tick reproduction caused by gene silencing of a blood digestion-related molecule.

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“…1962), used for this work, was from the colony kept in this laboratory since 1980 (Chinzei et al, 1983). Ticks were fed on rabbits.…”

Section: Animals Hemalymph Collection Ovary Exrractionmentioning

confidence: 99%

“…Vitellin (Vn) was purified from crude egg extract by high performance liquid chromatography (HpLC)-gel filtration and ion exchange chromatography, principally according to the procedure in Chinzei et al (1983). Anti-Vn serum was prepared from rabbits immunized with purified Vn.…”

Section: Vitellin (Vn) Purification and Preparation Of Anti-vn Serummentioning

confidence: 99%

Cypermethrin induction of vitellogenesis and ovarian development in unfed adult femaleOrnithodoros moubata(Acari: Argasidae)

Chinzei

Itoh

Ando

1989

Invertebrate Reproduction & Development

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Vitellogenesis in ticks is known to be induced by engorgement and mating. In this paper, the synthetic pyrethroid cypenethrin (CyM) is shown to induce production of yolk protein precursor, vitellogenin (Vg), and ovarian development in unengorged mated adult female Ornithodoros moubata. The levels of Vg found in the hemolymph and ovarian development induced by CyM were dose-dependent. i.e., CyM doses of more than 0.2 and 1.0 &tick were needed for significant increase of Vg titer in the hernolymph and yolk deposition in oocytes, respectively. Immunological and electrophoretical analyses of Vg and Vitellin (Vn) induced by CyM were identical with those induced by engorgement. Vg titer induced by CyM in unengorged females followed approximately the same time course as that in the normal engorged females. However, Vg titer induced by CyM continued to increase after day 8 and reached a maximum (95 pg/pl) on day 10 after treatment, while Vg titer induced by engorgement decreased again after reaching a maximum (60 &pl) on day 6, correlated with yolk Vn deposition in mcytes. Ovarian development induced by even high doses (10 or 20 pg/tick) of CyM was slow compared to normal development stimulated by engorgement. Oviposition was not observed in females treated with CyM.

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Purification and properties of vitellogenin and vitellin from a tick,Ornithodoros moubata

Cited by 69 publications

References 26 publications

Yolk degradation in tick eggs: I. Occurrence of a cathepsin L‐like acid proteinase in yolk spheres

Yolk degradation in tick eggs: I. Occurrence of a cathepsin L‐like acid proteinase in yolk spheres

RNA interference of cytosolic leucine aminopeptidase reduces fecundity in the hard tick, Haemaphysalis longicornis

Cypermethrin induction of vitellogenesis and ovarian development in unfed adult femaleOrnithodoros moubata(Acari: Argasidae)

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