Analyses of Antimicrobial Effector Genes, Larval Hemolymph Proteome, and Prophenoloxidase Activation System in Manduca sexta
Başlık:
Analyses of Antimicrobial Effector Genes, Larval Hemolymph Proteome, and Prophenoloxidase Activation System in Manduca sexta
Yazar:
He, Yan, author.
ISBN:
9780438086302
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (240 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-11(E), Section: B.
Advisors: Haobo Jiang Committee members: Junpeng Deng; Stephen Marek; Robert Matts.
Özet:
Manduca sexta is a lepidopteran model insect widely used to study insect physiological processes including innate immunity. Many immune pathways are activated upon tissue damage or pathogen invasion, which finally lead to blood clotting, melanization, antimicrobial molecule synthesis, phagocytosis, nodulation, and encapsulation. Some of these immune responses involve sequential cleavage activation of serine proteases, which are usually regulated by their inhibitors especially serpins.
In the genome of M. sexta, we identified 86 antimicrobial effector genes, most of which seem functional. They encode 15 cecropins, 6 moricins, 6 defensins, 3 gallerimycins, 4 X-tox splicing variants, 14 diapausins, 15 whey acidic protein homologs, 11 attacins, 1 gloverin, 4 lebocins, 6 lysozyme-related proteins, and 4 transferrins. Most of these genes' expression levels are up-regulated after an immune challenge.
Hemolymph is one of the major battle fields for insects to fight against invading pathogens in M. sexta. Using LC-MS/MS, we identified a total of 702 proteins in the cell-free plasma. Seventy of them showed 1.67 to >200 fold abundance increases after an immune challenge. There is no strong parallel between plasma protein levels and their transcript levels in hemocytes and fat body, but the level changes showed a better correlation. A group of proteins' molecular mass differ considerably from the calculated Mr's, providing evidence of post-translational modifications and indicating the existence of high Mr covalent immune complexes.
Proteome analysis identified 36 serine proteases and their homologs and 18 serpins. HP1, HP2, SP112, serpin-9, and serpin-13 were selected for functional studies. ProHP1 is involved in prophenoloxidase (proPO) activation, which finally leads to melanization. We provided evidence that proHP1 acts as an active zymogen for proHP6 activation, which forms complexes with several serpins at an unusual high Mr. Serpin-9 and -13 are two of the serpins that regulate proHP1* activity and they inhibit proPO activatation in vitro. We also identified two branches of serine protease pathways in the proPO activation system: HP14-HP2-PAP2 and SP112-HP2-PAP2. The expansion of knowledge on the serine protease network represents our recent efforts to gain insights into the molecular mechanisms of immune responses in M. sexta.
Notlar:
School code: 0664
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(687655.1) | 687655-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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