SK 66 -his, a Novel Glycine-Rich Peptide Derived from Drosophila with Antibacterial Activity

Specific Expression of Antimicrobial Peptides from the Black Soldier Fly in the Midgut of Silkworms (Bombyx mori) Regulates Silkworm Immunity

Antimicrobial peptides are molecules with strong antimicrobial activity and are of substantial interest for the immunization of insects. As a type of dipteran insect that can turn organic waste into animal feed, the black soldier fly (BSF) can "turn waste into treasure". In this study, we investigated the antimicrobial activity of the antimicrobial peptide genes, HiCG13551 and Hidiptericin-1, of BSF in silkworms, by overexpressing the genes specifically in the midgut. Changes in the mRNA levels of the transgenic silkworms after infection with Staphylococcus aureus were evaluated using transcriptome sequencing. The results showed that Hidiptericin-1 had stronger antimicrobial activity than HiCG13551. KEGG enrichment analysis showed that the differentially expressed genes in the transgenic overexpressed Hidiptericin-1 silkworm lines from the D9L strain were mainly enriched in the starch and sucrose metabolism, pantothenate and CoA biosynthesis, drug metabolism (other enzymes), biotin metabolism, platinum drug resistance, galactose metabolism, and pancreatic secretion pathways. In addition, immune-related genes were up-regulated in this transgenic silkworm strain. Our study may provide new insights for future immune studies on insects.

Indigenous knowledge system associated with the uses of insects for therapeutic or medicinal purposes in two main provinces of Burkina Faso, West Africa

BACKGROUND

Some insects are harmful to humans, plants and animals, but some of them can also be a source of proteins, fats, vitamins and minerals and be of therapeutic value. The therapeutic potential requires that medicinal insects and their derived products need to be scrutinized. This study highlights the indigenous knowledge related to their use of medicinal insects in peri-urban and urban areas of Burkina Faso.

METHODS

The survey was carried out among 60 traditional healers spread across two phytogeographical zones of Burkina Faso. The questionnaire focused on medicinal insects used by experienced traditional healers. Chi-square tests and principal component analysis were performed to test for significant differences regarding knowledge of how insects in phytogeographically different areas were used therapeutically in connection with different disease categories.

RESULTS

A total of 19 species of medicinal insects belonging to 6 orders were cited in connection with treatments of at least 78 pathologies and symptoms. Most frequently mentioned was gastroenteritis. Our study showed that 48.78% of the insects and their products were associated with 46 plant species for the treatment of pathologies. In addition, honey, beeswax and nests were the most widely insect products used.

CONCLUSION

The current study allows us to identify medicinal insects as well as their products used in the treatment of pathologies and symptoms, suggesting the presence of a considerable diversity of therapeutically important insect species. These insects are used alone and/or with their products but often in association with medicinal plants. The results constitute a useful database for future studies of medicinal insects in central and western parts of Burkina Faso.

Transgenic expression of antimicrobial peptides from black soldier fly enhance resistance against entomopathogenic bacteria in the silkworm, Bombyx mori

Antimicrobial peptides (AMPs) are effective molecules produced by the innate immune system of most organisms to fend off invading microbes and regarded as promising alternatives to conventional antibiotics due to their potent antimicrobial activities. The larvae of black soldier fly (BSF), Hermetia illucens, inhabit microbe-rich environments and its insect genome encodes a broad repertoire of AMPs. In the present study, three AMPs encoded by BSF Hidefensin-1, Hidiptericin-1 and HiCG13551 were cloned, expressed and purified in a recombinant Escherichia coli expression system. In vitro, both Hidefensin-1 and Hidiptericin-1 inhibited the growth of Streptococcus pneumoniae and Escherichia coli, while HiCG13551 inhibited the growth of Staphylococcus aureus and E. coli. Transmission electron microscopy showed that Hidiptericin-1 inhibited bacterial growth through bacterial membrane lysis. We also constructed a transgenic silkworm line constitutively expressing an AMP cassette HiAMP4516 encoding all the three AMPs, and the silkworms showed an increased resistance to both gram-positive and gram-negative entomopathogenic bacteria. These results provide insights into the antibacterial activities of BSF AMPs both in vitro and in vivo and suggest a great potential of exploiting insect-derived AMPs in silkworm disease resistance breeding.

Newly identified type II crustin (SpCrus2) in Scylla paramamosain contains a distinct cysteine distribution pattern exhibiting broad antimicrobial activity

Type II crustins are the most abundant type of crustins in shrimps that exhibit remarkable sequence diversities and broad antibacterial activities. This study characterized a novel type II crustin, SpCrus2, in the mud crab Scylla paramamosain. The SpCrus2 cDNA sequence is 620-bp long with a 495-bp open reading frame encoding a 164-amino acid protein. In the deduced protein, a 17-amino acid signal peptide, a glycine-rich hydrophobic region (GRR), and a cysteine-rich region (CRR) containing a whey acidic protein domain were predicted. SpCrus2 shares high similarity with most type II crustins (types IIa and IIb crustins) in shrimps but has a novel distribution pattern of cysteine residues that is distinct from most crustins. SpCrus2 and PlCrus3 from Pacifastacus leniusculus share high similarity and the same distribution pattern of cysteine residues. Thus, we proposed them as type IIc crustins. SpCrus2 is mainly distributed in the gills and can be up-regulated through Vibrio parahemolyticus or Staphylococcus aureus challenge. To investigate the biological functions of SpCrus2 and the underlying mechanisms, SpCrus2, GRR, CRR, and the mutant of CRR (CRR-M, the cysteine distribution pattern is mutated into that in most conventional crustins) were all overexpressed and purified. SpCrus2 GRR itself, as a glycine-rich amphiphilic peptide, exhibited evident antibacterial ability against Gram-negative bacteria, whereas CRR possessed potent antibacterial activity against Gram-positive bacteria. Either GRR or CRR exhibited weaker antibacterial activity than the whole protein of SpCrus2, indicating that GRR and CRR synergized to exert their potential antibacterial functions. In addition, CRR exhibited slightly stronger antimicrobial activity than CRR-M, suggesting that SpCrus2 containing this novel cysteine distribution pattern may exhibit stronger antimicrobial activity than most type II crustins with the conventional distribution pattern of cysteine residues. The likely antimicrobial ability of SpCrus2 may result from its microbial polysaccharide-binding and agglutination activities. Overall, this study characterized the first type II crustin in crabs and provided new insights into understanding the sequence and functional diversity of crustins and their immune functions in crustaceans.

Transcriptome Profiling Following Neuronal and Glial Expression of ALS-Linked SOD1 in Drosophila

Amyotrophic lateral sclerosis (ALS) generally is a late-onset neurodegenerative disease. Mutations in the Cu/Zn superoxide dismutase 1 (SOD1) gene account for approximately 20% of familial ALS and 2% of all ALS cases. Although a number of hypotheses have been proposed to explain mutant SOD1 toxicity, the molecular mechanisms of the disease remain unclear. SOD1-linked ALS is thought to function in a non-cell-autonomous manner such that motoneurons are critical for the onset, and glia contribute to progression of the disease. Recently, it has been shown in Drosophila melanogaster that expression of human SOD1 in a subset of neuronal cells causes synaptic transmission defects, modified motor function, and altered sensitivity to compounds that induce oxidative stress. Here we used the Gal4-UAS (Upstream Activation Sequence) system to further characterize flies expressing wild-type Drosophila SOD1 (dSOD1) and the mutant human SOD1^G85R (G85R) allele in motoneurons and glia. Cell-specific expression of both dSOD1 and G85R was found to influence lifespan, affect sensitivity to hydrogen peroxide, and alter lipid peroxidation levels. To better understand the genetic consequences of G85R expression in motoneurons and glia, we conducted microarray analysis of both young flies (5 days old) and old flies (45 days old) expressing G85R selectively in motoneurons or glia and concurrently in motoneurons and glia. Results from this microarray experiment identified candidate genes for further investigation and may help elucidate the individual and combined contributions of motoneurons and glia in ALS.

Antimicrobial activity of recombinant Pg-AMP1, a glycine-rich peptide from guava seeds

Antimicrobial peptides (AMPs) are compounds that act in a wide range of physiological defensive mechanisms developed to counteract bacteria, fungi, parasites and viruses. These molecules have become increasingly important as a consequence of remarkable microorganism resistance to common antibiotics. This report shows Escherichia coli expressing the recombinant antimicrobial peptide Pg-AMP1 previously isolated from Psidium guajava seeds. The deduced Pg-AMP1 open reading frame consists in a 168 bp long plus methionine also containing a His6 tag, encoding a predicted 62 amino acid residue peptide with related molecular mass calculated to be 6.98 kDa as a monomer and 13.96 kDa at the dimer form. The recombinant Pg-AMP1 peptide showed inhibitory activity against multiple Gram-negative (E. coli, Klebsiella pneumonia and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus and Staphylococcus epidermides) bacteria. Moreover, theoretical structure analyses were performed in order to understand the functional differences between natural and recombinant Pg-AMP1 forms. Data here reported suggest that Pg-AMP1 is a promising peptide to be used as a biotechnological tool for control of human infectious diseases.