Activation of both pathways is also important for the entry of AMPs to nucleus such as defensins, cecropins
, attacin, and gambicin, which have antiplasmodial activity .
In the silkworm, the AMPs have been identified into six groups: cecropins
[13-15], moricins , gloverins , attacins , enbocins , and lebocins [20, 21].
By consensus, known lepidopteran antimicrobial peptides are arranged into the families of defensins, cecropins
and moricins, attacins, gloverins, and lebocins (Rayaprolu et al.
Several inducible AMPs including cecropins
, sarcotoxins, defensins, thanatin, droscosin and coleoptericins had been well characterized in terms of the structures and mechanisms [20,21,22,23].
Among AMPs, cecropins
(Cec) are small (~4 kDa) peptides containing 35 to 39 amino acids, which are amphipathic, as a high proportion of basic amino acids are present at the N-terminus conferring a net positive charge and the hydrophobic amino acids are rich at the C-terminus (Sipos et al., 1992).
Several antimicrobial peptides produced by epithelial cells are widespread in animal kingdom ranging from Cecropins
in insects to Magainins in frogs and Bactenecins in cattle [9-11].
Andreu and colleagues (31), during study on cecropins
suggested that AMPs containing more tryptophan are being active against microorganisms.
(2) In 1981, the sequences of two antimicrobial peptides, cecropins
A and B, were identified in moths.
Zasloff suspects that magainins may be the vertebrate counterpart of cecropins
, 37-amino-acid-long antibacterial peptides found circulating in insects such as the Cecropia moth, which lacks both lymphocytes and antibodies.
P1 and novel nematode cecropins
: a bacteria-inducible antimicrobial peptide family in the nematode Ascaris suum," The Biochemical Journal, vol.
The four groups include Group 1, which consists of linear, cationic, and amphipathic-helical peptides, for example, cecropins
, magainins, bombinins, and temporins; Group 2, which consists of [beta]-strands connected by intramolecular disulfide bridges, for example, human [beta]-defensin-2, tachyplesins, and protegrins; Group 3, which consists of linear peptides with an extended structure, characterized by overrepresentation of one or more amino acids, for example, tritrpticin and indolicidin; and Group 4, which consists of peptides containing a looped structure, for example, bactenecin, brevinins, and esculentin.
The selected AMPs with tumoricidal properties are listed in Table 4.AMPssuchasmagainins , defensins , BMAP-27 and BMAP-28 , gaegurins , tachyplesin I, cecropins
, and melittin were reported to exhibit tumoricidal activity against melanoma and carcinoma cells both under in vitro and in vivo conditions.