Developmental regulation of BhSGAMP‐1, a gene encoding an antimicrobial peptide in the salivary glands of Bradysia hygida (Diptera, Sciaridae)

Abstract

It has recently become clear that the innate immune systems of insects and mammals are highly conserved; in general, these systems are stimulated upon infection by microorganisms. We found in the fly Bradysia hygida, a reiterated gene, which codes for a secretory peptide similar to plant-seed antimicrobial peptides. This gene BhSGAMP-1 is activated and expressed exclusively in the salivary glands of the larvae, while they are preparing to molt. In functional tests, synthetic BhSGAMP-1 peptide had broad spectrum antibiotic activity. Secretion of BhSGAMP-1 in the saliva could help prevent microbial infection during molting, by killing harmful microorganisms in the immediate vicinity of the animal. This is the first description of developmentally regulated defense peptide secretion in animals.

Antimicrobial activity of Stomoxys calcitransagainst Beauveria bassiana sensu lato isolates

“…Scanning electron microscopy demonstrated that conidia on the larval surface would be affected by a defense mechanism of mucus or integument, which would delay fungal development, similar to what was described for Bradysia hygida larvae with bacteria and yeast (CANDIDO-SILVA et al, 2007), for S. calcitrans adults with bacteria (BOULANGER et al, 2002) and for F. nigra larval secretions (URBANEK et al, 2012).…”

A BTB domain‐containing gene is upregulated by immune challenge

“…During this period, the insect become dangerously exposed to attack by microorganisms. Upregulation of some innate immunity genes is necessary (Candido-Silva et al, 2007). HaBBP was abundantly expressed during molting and metamorphosis in the fat body and hemocytes, and its distribution in the granulocytes and plasmatocytes suggests that it likely plays a role in innate immunity.…”

Bradysia hygida (Diptera, Sciaridae) presents two eukaryotic Elongation Factor 1A gene homologues: partial characterization of the eukaryotic Elongation Factor 1A-F1 gene

“…After the addition of EGTA, pH 8.0 (final concentration 2 mM), DNAse was inactivated by incubating the reaction for 10 min at 65°C. A mixture of 1 μg total RNA, 0.25 μg oligo(dT) 15 (Promega) and 0.25 μg Random Primer (Promega) was incubated at 70°C for 5 min, and quickly chilled in ice, prior to the addition of Improm-II Reverse Transcriptase (Promega). Reverse transcriptase (RT) reactions were performed according to manufacturer instructions.…”

“…In addition to gene amplification and transcription, several other processes have been investigated using the Sciaridae family as a model, including mechanisms of telomere maintenance (11,12), programmed cell death (13), establishment of dorsoventral polarity (14), and the immune response (15). These studies contributed to the understanding of these processes and further strengthened the view that the study of non-model organisms can contribute to the understanding of processes of general occurrence in metazoans.…”