Differential partitioning of maternal fatty acid and phospholipid in neonate mosquito larvae
Georgia C. Atella* and
Mohammed Shahabuddin
Laboratory of Malaria and Vector Research, National Institute of
Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
20892, USA
* Present address: Universidade Federal do Rio de Janeiro, UFRJ, Centro de
Ciências da Saúde, Instituto de Ciências Biomédicas,
Departamento de Bioquímica Médica, Ilha da Ciudade
Universitária, Rio de Janeiro, CEP 21941-590, Brazil

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Fig. 1. Uptake and distribution of lipophorin, fatty acid and
phosphatidylethanolamine by the ovary and oocyte of the mosquito Anopheles
gambiae strain G3. (A) Uptake of 32P-labeled lipophorin by
different stages (Christophers,
1911 ) of the developing ovary. (B) Localization of FITC-labeled
maternal lipophorin in developing oocytes. Scale bar, 25 µm. (C)
Phosphatidylethanolamine analog labeled with Texas Red (Texas Red-PE,
excitation 582 nm/emission 601 nm) on the polar head. (D) Fatty acid analog
labeled with BODIPY (BODIPY-FA, excitation 505 nm/emission 515 nm) on the acyl
chain. (E) Localization of the fatty acid (BODIPY-FA) in A. gambiae
oocytes. Scale bar, 15 µm. (F) Localization of phospholipid (Texas Red-PE)
in the same oocyte as in E. (G) Merged panels E and F demonstrate that fatty
acids and phosphatidylethanolamine colocalized in the same vesicles.
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Fig. 2. Maternal lipid localization in neonate mosquito larvae. Purified lipophorin
was double labeled with Texas Red-PE and BODIPY-FA before injecting into
vitellogenic females; eggs were collected and kept in water at 28°C until
larval hatching. The fluorescence associated with newborn larvae was examined
within 30 min after hatching. (A) Localization of BODIPY-FA in A.
gambiae larvae. (B) Localization of Texas Red-PE in the same newborn
larvae as shown in A. (C) Merged image of A and B shows differential
localization of BODIPY-FA and Texas Red-PE. (D) Phase-contrast image of the
same larvae as shown in C. (E) All neonate larvae hatched from the same batch
of eggs, showing identical pattern of differential partitioning of fatty acid
(BODIPY-FA) and phosphatidylethanolamine (Texas Red-PE). (F) Phase-contrast
image of the larvae shown in E. (G) Maternal lipid distribution in the larvae
of A. aegypti mosquitoes. (H) Phase-contrast image of larvae shown in
G. Scale bar, 200 µm.
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Fig. 3. Intact imported phosphatidylethanolamine in neonate A. gambiae
larvae. Texas Red-PE-loaded lipophorin was injected into vitellogenic females.
Extracted phospholipids from larvae were fractionated by thin-layer
chromatography. Fluorescence from the lipid analog was visualized by
illuminating the plate with UV light. Lane UL, unlabeled phospholipids
extracted from unlabeled neonate larvae; lane L, labeled phospholipids
extracted from neonate larvae hatched from eggs laid by the females injected
with Texas Red-PE; lane S, standard containing commercial Texas Red-PE that
was injected into the mosquitoes.
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Fig. 4. Distribution of phospholipids and fatty acids in neonate and embryonic
larvae. (A) BODIPY-labeled phosphatidylcholine analog (BODIPY-PC). (B)
Location of phosphatidylcholine analog (BODIPY-PC) in newly hatched A.
gambiae larvae. (C) Location of phosphatidylethanolamine analog (Texas
Red-PE) in the same larvae. (D) Phase-contrast image of the larvae shown in B
and C. Scale bar, 200µm. (E) Phase-contrast image of approximately 30-h-old
embryonic A. gambiae larvae. Scale bar, 150µm. (F) Fluorescent
image of the same larvae in E, showing the distribution of BODIPY-labeled
maternal fatty acid (BODIPY-FA). (G) Image of the same embryonic larvae
showing the distribution of the Texas Red-labeled maternal
phosphatidylethanolamine (Texas Red-PE). (H) Diagram of a neonate A.
gambiae larvae depicting the major accumulation sites of the maternal
phospholipids (red) and fatty acids (green).
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© The Company of Biologists Ltd 2002