Involvement of cecropin B in the formation of the Aedes aegypti mosquito cuticle

Abstract

In this study, we found a mosquito antimicrobial peptide (AMP), Aedes aegypti cecropin B (Aacec B), was expressed constitutively in pupae. Knockdown in the pupae of Aacec B using double-stranded RNA (dsRNA) resulted in high mortality, the emergence of deformed adults and an impairment of pharate adult cuticle formation with fewer lamellae being deposited and the helicoidal pattern of the chitin microfibrils being disorganized. Simultaneous injection of Aacec B dsRNA and Aacec B peptide into pupae significantly reduced this mortality and no deformed adults then emerged. The expression levels of Ae. aegypti prophenoloxidase (AaPPO) 3 and AaPPO 4 were significantly reduced in the Aacec B knockdown pupae. Exogenous Aacec B peptide significantly enhanced the transcription of AaPPO 3 in pupae. Knockdown of AaPPO 3 in pupae caused effects similar to Aacec B-knockdown. The Aacec B peptide could be detected in both the cytoplasm and nuclei of pupal cells and was able to bind to the TTGG(A/C)A motif in AaPPO 3 DNA both in vitro and in vivo. These findings suggest that Aacec B plays a crucial role in pharate adult cuticle formation via the regulation of AaPPO 3 gene expression in pupae.

Sex, Age, and Parental Harmonic Convergence Behavior Affect the Immune Performance ofAedes aegyptiOffspring

“…The mosquito innate immune system comprises several antimicrobial strategies with hemocytes playing a crucial role in the cellular immune response and antimicrobial peptides, pattern-recognition receptors and components of the phenoloxidase cascade being key components of the humoral immune response (66)(67)(68). Intra-thoracic injections of E. coli have been previously used to investigate cellular immune response of mosquitoes (69), measure expression of antimicrobial peptides in mosquitoes (70,71), age-associated mortality after bacterial challenge (72), and to compare immune response mechanisms between mosquito species (73). Similar to the melanization assay, female mosquitoes exhibited more robust bacterial killing responses and enhanced survival during bacterial infection relative to males of the same age and stage.…”

Magnetocaloric and Elastocaloric Effects in All‐d‐Metal Ni37Co9Fe4Mn35Ti15 Magnetic Shape Memory Alloy

“…It should be noted that the Gibbs free energy curve tends to shift to a lower level for www.advancedsciencenews.com www.pss-a.com martensite with the application of uniaxial stress, which will result in a higher equivalent temperature. [36] When the input work is sufficiently large to overcome the energy barrier for forward MT, stress-induced MT can occur even above the MT temperature. [36] Figure 4a shows the compressive stress-strain curves with the uniaxial stress from 200 to 400 MPa.…”

“…[36] When the input work is sufficiently large to overcome the energy barrier for forward MT, stress-induced MT can occur even above the MT temperature. [36] Figure 4a shows the compressive stress-strain curves with the uniaxial stress from 200 to 400 MPa. As shown in Figure 4a, the superelastic behavior is observed, suggesting that MT can be driven by uniaxial stresses.…”

Identification of silkworm hemocyte subsets and analysis of their response to BmNPV infection based on single-cell RNA sequencing

“…The high expression of Cecropin B genes (6 genes belonging to the same cluster on chromosome 26 with log2FC values of 2.9, 2.8, 2.6, 2.4, 2.2, and 2.0) in the uninfected condition may reflect a regulatory function in developmental processes such as cuticle formation via the regulation of prophenoloxidase expression (Liu et al, 2017) (as opposed to a defense against bacterial infection). The increased expression of IMP-L2 and Cecropins indicates that cluster 9 may be associated with humoral immunity or have a regulatory function by the secretion of cytokines.…”