Lipophorin-facilitated hydrocarbon uptake by oocytes in the German cockroach Blattella germanica (L.)
Yongliang Fan1,
Jody Chase2,
Veeresh L. Sevala1,* and
Coby Schal1,
1 Department of Entomology, Box 7613, North Carolina State University, Raleigh, NC 27695-7613, USA and
2 Directorate for Education and Human Resources, National Science Foundation, 4201 Wilson Boulevard, Suite 875, Arlington, VA 22230, USA
* Present address: Paradigm Genetics, Research Triangle Park, NC 27709, USA
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Fig. 1. Hydrocarbon (HC) content of the hemolymph, ovaries and first and second egg cases. Hydrocarbon content was determined by gas chromatography. Inset: time course of the reproductive cycle, represented by oocyte length; oviposition occurs on day 9 and pregnancy follows. The images represent a vitellogenic female (left) between days 0 and 8 and a ‘pregnant’ female (right) between days 9 and 28. Values are means ±1 S.E.M.; some error bars are obscured by the symbol. N=7 for each mean except on day 7, where N=5, and day 8, where N=9.
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Fig. 2. Age-dependent in vivo hydrocarbon (HC) deposition in the ovary and epicuticle in relation to the reproductive cycle. [3H]3,11-Dimethylnonacosane (21.46 kBq) was injected in 0.4 µl of hexane into the hemocoel of females of various ages, and uptake of [3H]3,11-dimethylnonacosane by the ovary (A) and epicuticle (B) was assayed 24 h later. Values are means ±1 S.E.M.; some error bars are obscured by the symbol. N=8 for each mean, except on day 0, where N=10, day 1, where N=13, day 6, where N=6, and day 8, where N=9.
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Fig. 3. Accumulation of newly synthesized hydrocarbons (HCs) in the ovary in vitro. An ovary from a day 4 female was co-incubated with abdominal sternites 3 and 4 from a day 5 female in 500 µl of TC199 medium containing 25.9 kBq of [1-14C]propionate and 0–50 % Blattella germanica plasma. Values are means ±1 S.E.M. (N=3–5). Some error bars are obscured by the symbol.
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Fig. 4. Accumulation of newly synthesized hydrocarbons (HCs) in the medium and ovary in vitro. An ovary from a day 4 female was co-incubated with abdominal sternites 3 and 4 from a day 5 female in 500 µl of TC199 medium containing 25.9 kBq of [1-14C]propionate and various concentrations of purified Blattella germanica lipophorin. (A) SDS–PAGE of hemolymph (H) and purified lipophorin (Lp). (B) Accumulation of newly synthesized hydrocarbons in the medium; r2=0.999, P<0.0001. (C) Accumulation of newly synthesized hydrocarbons in the ovary. Values are means ±1 S.E.M. (N=3–5). Some error bars are obscured by the symbol.
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Fig. 5. Ovarian uptake of hydrocarbons (HCs) in vitro. (A) [3H]3,11-Dimethylnonacosane (21.46 kBq) was topically applied onto sternites 3 and 4 of a day 5 female, and the sternites were then co-incubated in TC199 with ovaries of different ages in the presence of 1 mg ml–1 purified high-density lipophorin (HDLp). [3H]3,11-Dimethylnonacosane levels in the ovary were assayed by liquid scintillation spectrometry. (B) Sternites 3 and 4 from a day 6 female were co-incubated with an ovary from a day 6, 7, 8 or 9 female in 500 µl of TC199 medium containing 10 % hemolymph and [1-14C]propionate (25.9 kBq). Both sets of incubations were at 27°C for 24 h. Values are means ±1 S.E.M. (N=8). Some error bars are obscured by the symbol.
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Fig. 6. Accumulation of lipophorin in ovaries in vivo. The amount of lipophorin in the ovaries and egg case was determined by ELISA. Values are means ±1 S.E.M. (N=9). Some error bars are obscured by the symbol.
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© The Company of Biologists Ltd 2002
