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The host-seeking inhibitory peptide, Aea-HP-1, is made in the male accessory gland and transferred to the female during copulation.

Naccarati C, Audsley N, Keen JN, Kim JH, Howell GJ, Kim YJ, Isaac RE - Peptides (2011)

Bottom Line: The structure of the peptide with its blocked N- and C-termini confers resistance to metabolic inactivation by MAG peptidases; however the peptide persists for less than 2h in the female reproductive tract after copulation.Aea-HP-1 is not a ligand for the mosquito sex peptide/myoinhibitory peptide receptor.A. aegypti often mate close to the host and therefore it is possible that male-derived Aea-HP-1 induces short-term changes to female host-seeking behavior to reduce potentially lethal encounters with hosts soon after insemination.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Biological Sciences, University of Leeds, Leeds, UK. bs09cn@leeds.ac.uk

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MALDI/TOF mass spectra of a peptide extract of MAGs/SVs (A) and whole MAGs (B). (A) Five pairs of tissues were extracted into acidified methanol (0.1 ml) of which 1 μl of the sample was mixed with 1 μl MALDI matrix solution and dried on a MALDI plate for analysis. The spectrum shows the presence of prominent peaks at m/z 1211.8 and 1227.8. (B) A pair of MAGs from a single male mosquito were placed directly on a MALDI plate, rinsed with water to eliminate salts, mixed with matrix solution, dried and analyzed as described in Section 2.
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fig0005: MALDI/TOF mass spectra of a peptide extract of MAGs/SVs (A) and whole MAGs (B). (A) Five pairs of tissues were extracted into acidified methanol (0.1 ml) of which 1 μl of the sample was mixed with 1 μl MALDI matrix solution and dried on a MALDI plate for analysis. The spectrum shows the presence of prominent peaks at m/z 1211.8 and 1227.8. (B) A pair of MAGs from a single male mosquito were placed directly on a MALDI plate, rinsed with water to eliminate salts, mixed with matrix solution, dried and analyzed as described in Section 2.

Mentions: Peptides were extracted from MAGs plus SVs for analysis by MALDI/TOF-MS. The spectrum (m/z 800–4000) revealed two prominent monoisotopic peaks, one at m/z, 1227.8 and a less intense peak at m/z, 1211.8 (Fig. 1a). The mass difference of 16 Da between these peaks suggested they might be related, with a difference in oxidation state between them. The molecular ion (m/z, 1227.8) was subjected to post-source decay analysis and the fragmentation spectra generated revealed the amino acid sequence of the parent peptide as pERPhPSLKTRFamide (pE, pyro-glutamic acid, hP, 4-hydroxyproline; amide, amidated C-terminus; Fig. 2). The sequence was identical to a neuropeptide previously isolated from A. aegypti heads collected from a mixed sex population and known as the head peptide or Aea-HP-1 [30]. Aea-HP-1 is modified post-translationally in three places, including hydroxylation of one proline residue. The fully modified mature peptide has a theoretical molecular mass ion m/z of 1227.7, which agrees closely with the m/z peaks observed in our spectra. The second peak at m/z, approx. 1211.7 most likely represents a version of the peptide known as Aea-HP-3 [39], in which the proline at position four was not hydroxylated. An almost identical fragment ion spectrum was generated when synthetic Aea-HP-1 was analyzed in the same manner (not shown). An extract from a total of 70 pairs of MAGs and SVs was fractionated using RP-HPLC and MALDI/TOF-MS analysis of collected fractions established that the retention times of the natural and synthetic Aea-HP-1 were identical.


The host-seeking inhibitory peptide, Aea-HP-1, is made in the male accessory gland and transferred to the female during copulation.

Naccarati C, Audsley N, Keen JN, Kim JH, Howell GJ, Kim YJ, Isaac RE - Peptides (2011)

MALDI/TOF mass spectra of a peptide extract of MAGs/SVs (A) and whole MAGs (B). (A) Five pairs of tissues were extracted into acidified methanol (0.1 ml) of which 1 μl of the sample was mixed with 1 μl MALDI matrix solution and dried on a MALDI plate for analysis. The spectrum shows the presence of prominent peaks at m/z 1211.8 and 1227.8. (B) A pair of MAGs from a single male mosquito were placed directly on a MALDI plate, rinsed with water to eliminate salts, mixed with matrix solution, dried and analyzed as described in Section 2.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3368272&req=5

fig0005: MALDI/TOF mass spectra of a peptide extract of MAGs/SVs (A) and whole MAGs (B). (A) Five pairs of tissues were extracted into acidified methanol (0.1 ml) of which 1 μl of the sample was mixed with 1 μl MALDI matrix solution and dried on a MALDI plate for analysis. The spectrum shows the presence of prominent peaks at m/z 1211.8 and 1227.8. (B) A pair of MAGs from a single male mosquito were placed directly on a MALDI plate, rinsed with water to eliminate salts, mixed with matrix solution, dried and analyzed as described in Section 2.
Mentions: Peptides were extracted from MAGs plus SVs for analysis by MALDI/TOF-MS. The spectrum (m/z 800–4000) revealed two prominent monoisotopic peaks, one at m/z, 1227.8 and a less intense peak at m/z, 1211.8 (Fig. 1a). The mass difference of 16 Da between these peaks suggested they might be related, with a difference in oxidation state between them. The molecular ion (m/z, 1227.8) was subjected to post-source decay analysis and the fragmentation spectra generated revealed the amino acid sequence of the parent peptide as pERPhPSLKTRFamide (pE, pyro-glutamic acid, hP, 4-hydroxyproline; amide, amidated C-terminus; Fig. 2). The sequence was identical to a neuropeptide previously isolated from A. aegypti heads collected from a mixed sex population and known as the head peptide or Aea-HP-1 [30]. Aea-HP-1 is modified post-translationally in three places, including hydroxylation of one proline residue. The fully modified mature peptide has a theoretical molecular mass ion m/z of 1227.7, which agrees closely with the m/z peaks observed in our spectra. The second peak at m/z, approx. 1211.7 most likely represents a version of the peptide known as Aea-HP-3 [39], in which the proline at position four was not hydroxylated. An almost identical fragment ion spectrum was generated when synthetic Aea-HP-1 was analyzed in the same manner (not shown). An extract from a total of 70 pairs of MAGs and SVs was fractionated using RP-HPLC and MALDI/TOF-MS analysis of collected fractions established that the retention times of the natural and synthetic Aea-HP-1 were identical.

Bottom Line: The structure of the peptide with its blocked N- and C-termini confers resistance to metabolic inactivation by MAG peptidases; however the peptide persists for less than 2h in the female reproductive tract after copulation.Aea-HP-1 is not a ligand for the mosquito sex peptide/myoinhibitory peptide receptor.A. aegypti often mate close to the host and therefore it is possible that male-derived Aea-HP-1 induces short-term changes to female host-seeking behavior to reduce potentially lethal encounters with hosts soon after insemination.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Biological Sciences, University of Leeds, Leeds, UK. bs09cn@leeds.ac.uk

Show MeSH
Related in: MedlinePlus