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1.
Acta Crystallogr D Struct Biol ; 77(Pt 7): 894-903, 2021 Jul 01.
Article in English | MEDLINE | ID: mdl-34196616

ABSTRACT

Antimicrobial peptides (AMPs) are small amphipathic peptides that exhibit bactericidal activity against a wide range of pathogenic microorganisms and are considered to be potential substitutes for antibiotics effective against microbial infection. PSK, an 84-amino-acid AMP recently isolated from Chrysomya megacephala larvae, probably belongs to the mitochondrial ATPase inhibitor family according to its sequence. No member of this family from an insect has been structurally characterized to date. In this study, the crystal structure of full-length PSK determined by molecular replacement using an ab initio modeled ensemble as a search model and a solution structure obtained from small-angle X-ray scattering (SAXS) measurements are reported. The crystal structure reveals a distinct fold compared with those of homologous peptides, in that PSK comprises two antiparallel α-helices rather than a single long helix, which is in good agreement with the SAXS-based ab initio model. However, the peptide exists as a monomer in solution, even though a stable dimer was observed in the crystal structure. This apparent contradiction may reflect different oligomerization states that may be implicated in its bioactivity. The data presented here have established a solid basis for further mechanistic studies of this novel insect AMP.


Subject(s)
Antimicrobial Peptides/chemistry , Calliphoridae/metabolism , Enzyme Inhibitors/chemistry , Amino Acid Sequence , Animals , Models, Molecular , Protein Conformation
2.
Med Vet Entomol ; 35(2): 225-229, 2021 06.
Article in English | MEDLINE | ID: mdl-33063897

ABSTRACT

Antibiotic-resistant bacteria pose a major threat to global health in the 21st century, requiring a quick, cheap and effective response from public health officials. This study evaluated the antimicrobial activity of native excretions/secretions (NES) produced by third instar (3 days old) larvae of Calliphora vicina using a protocol adapted from the Institute of Clinical and Laboratory Standards (CLSI). The microorganisms tested were: Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and the fungus Candida albicans. After the incubation period, the suspensions were diluted and spread on nutrient agar plates to count the colony-forming units. A turbidimetric test also was carried out to test the action of the NES of C. vicina against S. aureus, a very common bacterial species, with an enormous capacity for adaption and resistance, being one of the bacteria of medical importance that causes the most hospital and community infections in the world. According to our results, the NES of C. vicina exhibits antimicrobial activity at different dilutions, being most effective against the gram-negative bacteria E. coli and K. pneumoniae.


Subject(s)
Anti-Bacterial Agents , Antifungal Agents , Biological Products , Calliphoridae/metabolism , Gram-Negative Bacteria/drug effects , Animals , Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology , Antifungal Agents/metabolism , Antifungal Agents/pharmacology , Biological Products/metabolism , Biological Products/pharmacology , Candida albicans , Diptera , Escherichia coli/drug effects , Klebsiella pneumoniae/drug effects , Larva/metabolism , Microbial Sensitivity Tests/methods , Staphylococcus aureus/drug effects
3.
J Med Entomol ; 58(1): 47-55, 2021 01 12.
Article in English | MEDLINE | ID: mdl-32700732

ABSTRACT

The minimum postmortem interval (PMImin) could be evaluated from the developmental stage of forensically important insects colonize a corpse, such as blow flies (Diptera: Calliphoridae). Unlike larvae, the developmental stage of which is well established according to their morphology, estimating the age of pupae is proven to be challenging. Recently, several studies reported the regulation of special genes during the development of blow fly pupae. However, gene regulation in Aldrichina grahami during the intrapuparial period remains to be studied. Therefore, we set out to investigate the mRNA levels of heat shock protein 23 (Hsp23), heat shock protein 24 (Hsp24), and 1_16 during the metamorphosis of A. grahami pupae. First, we examined seven candidate reference genes (ribosomal protein 49 (RP49), 18S ribosomal RNA (18S rRNA), 28S ribosomal RNA (28S rRNA), beta-tubulin at 56D (ß-tubulin), Ribosomal protein L23 (RPL23), glutathione S-transferase (GST1), and Actin. Three widely used algorithms (NormFinder, BestKeeper, and geNorm) were applied to evaluate the mRNA levels of reference gene candidates in puparium at three stable temperatures (15, 22, and 27°C). Next, mRNA expression of Hsp23, Hsp24, and 1_16 during A. grahami metamorphosis was examined. We demonstrated that mRNA expression levels of Hsp23, Hsp24, and 1_16 showed time-specific regulation. In summary, our study identified three gene markers for the intrapuparial period of A. grahami and might provide a potential application in PMImin estimation.


Subject(s)
Calliphoridae , Forensic Entomology/methods , Animals , Calliphoridae/genetics , Calliphoridae/growth & development , Calliphoridae/metabolism , Gene Expression , Genes, Insect , Genetic Markers , Heat-Shock Proteins/genetics , Heat-Shock Proteins/metabolism , Larva/growth & development , Metamorphosis, Biological , Postmortem Changes , Pupa/growth & development
4.
Insect Biochem Mol Biol ; 127: 103493, 2020 12.
Article in English | MEDLINE | ID: mdl-33157229

ABSTRACT

The oncometabolite L-2-hydroxyglutarate (L-2HG) is considered an abnormal product of central carbon metabolism that is capable of disrupting chromatin architecture, mitochondrial metabolism, and cellular differentiation. Under most circumstances, mammalian tissues readily dispose of this compound, as aberrant L-2HG accumulation induces neurometabolic disorders and promotes renal cell carcinomas. Intriguingly, Drosophila melanogaster larvae were recently found to accumulate high L-2HG levels under normal growth conditions, raising the possibility that L-2HG plays a unique role in insect metabolism. Here we explore this hypothesis by analyzing L-2HG levels in 18 insect species. While L-2HG was present at low-to-moderate levels in most of these species (<100 pmol/mg; comparable to mouse liver), dipteran larvae exhibited a tendency to accumulate high L-2HG concentrations (>100 pmol/mg), with the mosquito Aedes aegypti, the blow fly Phormia regina, and three representative Drosophila species harboring concentrations that exceed 1 nmol/mg - levels comparable to those measured in mutant mice that are unable to degrade L-2HG. Overall, our findings suggest that one of the largest groups of animals on earth commonly generate high concentrations of an oncometabolite during juvenile growth, hint at a role for L-2HG in the evolution of dipteran development, and raise the possibility that L-2HG metabolism could be targeted to restrict the growth of key disease vectors and agricultural pests.


Subject(s)
Aedes/metabolism , Calliphoridae/metabolism , Drosophila/metabolism , Glutarates/metabolism , Aedes/growth & development , Animals , Calliphoridae/growth & development , Drosophila/growth & development , Larva/growth & development , Larva/metabolism
5.
J Evol Biol ; 33(10): 1468-1486, 2020 10.
Article in English | MEDLINE | ID: mdl-32722879

ABSTRACT

Cuticular hydrocarbons (CHCs) are organic compounds found on the cuticles of all insects which can act as close-contact pheromones, while also providing a hydrophobic barrier to water loss. Given their widespread importance in sexual behaviour and survival, CHCs have likely contributed heavily to the adaptation and speciation of insects. Despite this, the patterns and mechanisms of their diversification have been studied in very few taxa. Here, we perform the first study of CHC diversification in blowflies, focussing on wild populations of the ecologically diverse genus Chrysomya. We convert CHC profiles into qualitative and quantitative traits and assess their inter- and intra-specific variation across 10 species. We also construct a global phylogeny of Chrysomya, onto which CHCs were mapped to explore the patterns of their diversification. For the first time, we demonstrate that blowflies express an exceptional diversity of CHCs, which have diversified in a nonphylogenetic and punctuated manner, are species-specific and sexually dimorphic. It is likely that both ecological and sexual selection have shaped these patterns of CHC diversification, and our study now provides a comprehensive framework for testing such hypotheses.


Subject(s)
Animal Shells/metabolism , Calliphoridae/genetics , Hydrocarbons , Phylogeny , Sex Characteristics , Animals , Calliphoridae/metabolism , Female , Male , Species Specificity
6.
Article in English | MEDLINE | ID: mdl-31709462

ABSTRACT

To navigate through the environment, animals rely on visual feedback to control their movements relative to their surroundings. In dipteran flies, visual feedback is provided by the wide-field motion-sensitive neurons in the visual system called lobula plate tangential cells (LPTCs). Understanding the role of LPTCs in fly behaviors can address many fundamental questions on how sensory circuits guide behaviors. The blowfly was estimated to have ~ 60 LPTCs, but only a few have been identified in Drosophila. We conducted a Gal4 driver screen and identified five LPTC subtypes in Drosophila, based on their morphological characteristics: LPTCs have large arborizations in the lobula plate and project to the central brain. We compared their morphologies to the blowfly LPTCs and named them after the most similar blowfly cells: CH, H1, H2, FD1 and FD3, and V1. We further characterized their pre- and post-synaptic organizations, as well as their neurotransmitter profiles. These anatomical features largely agree with the anatomy and function of their likely blowfly counterparts. Nevertheless, several anatomical details indicate the Drosophila LPTCs may have more complex functions. Our characterization of these five LPTCs in Drosophila will facilitate further functional studies to understand their roles in the visual circuits that instruct fly behaviors.


Subject(s)
Brain/physiology , Calliphoridae/physiology , Drosophila melanogaster/physiology , Motion Perception , Neurons/physiology , Vision, Ocular , Animals , Animals, Genetically Modified , Behavior, Animal , Brain/metabolism , Calliphoridae/metabolism , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Drosophila melanogaster/genetics , Drosophila melanogaster/metabolism , Neurons/metabolism , Optic Lobe, Nonmammalian , Photic Stimulation , Species Specificity , Transcription Factors/genetics , Transcription Factors/metabolism , Visual Pathways/physiology
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