Selection and Evaluation of Tissue Specific Reference Genes in Lucilia sericata during an Immune Challenge

Therapeutic effects of Lucilia sericata larval excretion/secretion products on Leishmania major under in vitro and in vivo conditions

Background

Leishmaniasis is a neglected infectious disease caused by protozoa of the genus Leishmania. The disease generally manifests as characteristic skin lesions which require lengthy treatment with antimonial drugs that are often associated with adverse side effects. Therefore, a number of studies have focused on natural compounds as promising drugs for its treatment. This study aimed to evaluate the effects of larval excretion/secretion products (ES) of Lucilia sericata in crude and fractionated forms on Leishmania major, by using in vitro and in vivo models.

Methods

The in vitro experiments involved evaluation of ES on both promastigotes and macrophage-engulfed amastigotes, whereas the in vivo experiments included comparative treatments of skin lesions in L. major-infected mice with Eucerin-formulated ES and Glucantime.

Results

The half maximal inhibitory concentrations of the crude ES, > 10-kDa ES fraction, < 10-kDa ES fraction, and Glucantime were 38.7 μg/ml, 47.6 μg/ml, 63.3 μg/ml, and 29.1 μg/ml, respectively. Significant differences were observed between percentage viabilities of promastigotes treated with the crude ES and its fractions compared with the negative control (P < 0.0001). The crude ES was more effective on amastigotes than the two ES fractions at 300 μg/ml. The macroscopic measurements revealed that the reduction of lesion size in mice treated with the crude ES followed quicker cascades of healing than that of mice treated with Glucantime and the ES fractions.

Conclusions

The present study showed that the larval ES of L. sericata in both crude and fractionated forms are effective for both intracellular and extracellular forms of L. major. Also, the ES exert both topical and systemic effects on mice experimentally infected with L. major.

Graphical abstract

Reference Gene Selection for Normalizing Gene Expression in Ips Sexdentatus (Coleoptera: Curculionidae: Scolytinae) Under Different Experimental Conditions

Ips sexdentatus (Coleoptera: Curculionidae: Scolytinae) is one of the most destructive and economically important forest pests. A better understanding of molecular mechanisms underlying its adaptation to toxic host compounds may unleash the potential for future management of this pest. Gene expression studies could be considered as one of the key experimental approaches for such purposes. A suitable reference gene selection is fundamental for quantitative gene expression analysis and functional genomics studies in I. sexdentatus. Twelve commonly used reference genes in Coleopterans were screened under different experimental conditions to obtain accurate and reliable normalization of gene expression data. The majority of the 12 reference genes showed a relatively stable expression pattern among developmental stages, tissue-specific, and sex-specific stages; however, some variabilities were observed during varied temperature incubation. Under developmental conditions, the Tubulin beta-1 chain (β-Tubulin) was the most stable reference gene, followed by translation elongation factor (eEF2) and ribosomal protein S3 (RPS3). In sex-specific conditions, RPS3, β-Tubulin, and eEF2 were the most stable reference genes. In contrast, different sets of genes were shown higher stability in terms of expression under tissue-specific conditions, i.e., RPS3 and eEF2 in head tissue, V-ATPase-A and eEF2 in the fat body, V-ATPase-A and eEF2 in the gut. Under varied temperatures, β-Tubulin and V-ATPase-A were most stable, whereas ubiquitin (UbiQ) and V-ATPase-A displayed the highest expression stability after Juvenile Hormone III treatment. The findings were validated further using real-time quantitative reverse transcription PCR (RT-qPCR)-based target gene expression analysis. Nevertheless, the present study delivers a catalog of reference genes under varied experimental conditions for the coleopteran forest pest I. sexdentatus and paves the way for future gene expression and functional genomic studies on this species.

Evaluation of Reference Genes and Age Estimation of Forensically Useful Aldrichina grahami (Diptera: Calliphoridae) During Intrapuparial Period

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 (β-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.

Development of Sarcophaga dux (diptera: Sarcophagidae) at constant temperatures and differential gene expression for age estimation of the pupae

Sarcophaga dux (Diptera: Sarcophagidae) is a necrophagous flesh fly species with potential forensic value for estimating minimum postmortem interval (PMI_min). The basic developmental data and precise age estimates of the pupae are significant for PMI_min estimation in forensic investigations. In the present study, we investigated the development data of that species at seven constant temperatures varying from 16 °C to 34 °C, including body length changes of the larve, developmental duration and accumulated degree hours of the preadults. Several reference genes for relative quantification of the differentially expressed genes (DEGs) were firstly selected and evaluated in the pupae of different ages under different temperatures. The DEGs of the insects during the pupal period at different constant temperatures (34, 25 and 16 °C) were further analyzed for more precise age estimation. The results showed that the developmental durations of the preadults at 16, 19, 22, 25, 28, 31 and 34 °C were 1478.6 ± 18.3 h, 726.1 ± 15.8 h, 538.5 ± 0.9 h, 394.1 ± 9.5 h, 375.6 ± 10.8 h, 284.1 ± 7.3 h, and 252.5 ± 6.1 h, respectively. The developmental threshold temperature the flies was 12.27 ± 0.35 °C, and the thermal summation constant was 5341.71 ± 249.29° hours. The most reliable reference genes during the pupal period at different temperatures were found: GST1 and 18S rRNA for the 34 °C group, GST1 and RPL49 for 25 °C, and 18S rRNA and 28S rRNA for 16 °C. The four differential expression genes (Hsp60, A-alpha, ARP, and RPL8) have the potential to be used for more precise age estimation of pupal S. dux. This work provides important basic developmental data and a more precise age estimation method for pupal S. dux, and improves the value of this species for PMI_min estimation in forensic investigations.

Lysine Acetyltransferase p300/CBP Plays an Important Role in Reproduction, Embryogenesis and Longevity of the Pea Aphid Acyrthosiphon pisum

CREB-binding protein (p300/CBP) is a universal transcriptional co-regulator with lysine acetyltransferase activity. Drosophila melanogaster p300/CBP is a well-known regulator of embryogenesis, and recent studies in beetles and cockroaches have revealed the importance of this protein during post-embryonic development and endocrine signaling. In pest insects, p300/CBP may therefore offer a useful target for control methods based on RNA interference (RNAi). We investigated the role of p300/CBP in the pea aphid (Acyrthosiphon pisum), a notorious pest insect used as a laboratory model for the analysis of complex life-history traits. The RNAi-based attenuation of A. pisum p300/CBP significantly reduced the aphid lifespan and number of offspring, as well as shortening the reproductive phase, suggesting the manipulation of this gene contributes to accelerated senescence. Furthermore, injection of p300/CBP dsRNA also reduced the number of viable offspring and increased the number of premature nymphs, which developed in abnormally structured ovaries. Our data confirm the evolutionarily conserved function of p300/CBP during insect embryogenesis and show that the protein has a critical effect on longevity, reproduction and development in A. pisum. The potent effect of p300/CBP silencing indicates that this regulatory protein is an ideal target for RNAi-based aphid control.

Differential Gene Expression for Age Estimation of Forensically Important Sarcophaga peregrina (Diptera: Sarcophagidae) Intrapuparial

Sarcophaga peregrina is an important flesh fly species for estimating the minimum postmortem interval (PMImin) in forensic entomology. The accurate determination of the developmental age is a crucial task for using necrophagous sarcophagids to estimate PMImin. During larval development, the age determination is straight forward by the morphological changes and variation of length, weight, and width; however, the age estimation of sarcophagid intrapuparial is more difficult due to anatomical and morphological changes not being visible. The analysis of differentially expressed genes (DEGs) during sarcophagid metamorphosis is a potential method for age estimation of intrapuparial. In the present study, real-time quantitative polymerase chain reaction (RT-qPCR) was used to analyze the differential gene expression level of S. peregrina intrapuparial in different constant temperatures (35°C, 25°C, and 15°C). In addition, the appropriate reference genes of S. peregrina were selected in the intrapuparial and at different temperatures to obtain reliable and valid gene expression profiles. The results indicated that two candidate genes (18S rRNA and 28S rRNA) were the most reliable reference genes, and four DEGs (Hsp90, A-alpha, AFP, AFBP) have the potential to be used to more accuracy estimate the age of S. peregrina intrapuparial.

Biodegradation of typical BFRs 2,4,6-tribromophenol by an indigenous strain Bacillus sp. GZT isolated from e-waste dismantling area through functional heterologous expression

Legacy wastewater contaminants from e-waste dismantling process such as 2,4,6-tribromophenol (TBP), one of the most widely used brominated flame retardants (BFRs), have raised concern owing to their toxicity and recalcitrance. Our previously isolated Bacillus sp. GZT from river sludge in e-waste dismantling area is a good candidate for bioremediation of BFRs contaminated sites considering its remarkable degradability of TBP and its intermediates. However, there exists a new challenge because bio-degrader cannot produce enough biomass or metabolic activity to cleanup TBP in practice complex environment. Here, we heterologously expressed and functionally characterized the genes and enzymes responsible for TBP degradation to examine the feasibility of enhancing the ability of this microorganism to detoxify TBP. Results demonstrated that five recombinant strains containing functional genes, designated tbpA, tbpB, tbpC, tbpD, and tbpE, become more tolerant toward a wide range of brominated compounds than the nontransgenic strain. Cytochrome P450 reductase encoded by tbpA gene could greatly increase efficiency to remove TBP (98.8%), as compared to wild-type strain GZT (93.2%). Its debromination intermediates 2,4-dibromophenol, 2,6-dibromo-4-methylphenol and 2-bromophenol were significantly metabolized by halophenol dehalogenases encoded by tbpB, tbpC, and tbpD, respectively. Finally, under the function of tbpE gene encoding enzyme, further debrominated product (phenol) was dramatically detoxified. To reduce the risk of these xenobiotics, the expression of these genes can be induced and significantly up-regulated during exposure to them. These results open broad scope for future study in developing genetic engineering technologies for more efficient remediation wastewater of e-waste recycling sites contaminated with TBP, which would certainly be important steps to lower TBP exposures and prevent potential health effects.

Investigation of antimicrobial effects of treated Lucilia sericata larvae extract on bacteria

BACKGROUND AND OBJECTIVES

Larval therapy refers to the use of Lucilia sericata larvae on chronic wounds, which is a successful method of chronic wounds treatment. The secretions of these larvae contain antibacterial compounds and lead to death or inhibition of bacterial growth.

MATERIALS AND METHODS

In this study, we investigated the antibacterial effects of Lucilia sericata larvae secretions which were in sterilized and multi antibiotic-resistant bacteria-treated forms on Gram-positive Bacillus subtilis bacteria and Gram-negative Escherichia coli bacteria. In the following, we evaluated changes in gene expression of lucifensin and attacin during treatment with multi antibiotic-resistant bacteria. Investigation of the antibacterial effect was carried out using optical absorption and antibiotic disk diffusion in order to study the expression of the aforementioned genes.

RESULTS

The results of this study showed that E. coli-treated larvae were able to inhibit the growth of E. coli and secretions of B. subtilis-treated larvae and were also able to inhibit the growth of B. subtilis. Gene expression of antibacterial peptides in multi antibiotic-resistant bacteria-treated larvae was increased in comparison to non-treated larvae.

CONCLUSION

Due to the significant antibacterial potency of bacteria-treated larvae secretions, the secretions can be a suitable candidate as a drug against antibiotic resistant bacteria, but additional tests are required. Since the antimicrobial peptides of insects have not yet produced any resistance in human pathogenic bacteria, they can be considered as a promising strategy for dealing with resistant infections.

Selection of Reference Genes for the Normalization of RT-qPCR Data in Gene Expression Studies in Insects: A Systematic Review

Reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) is a reliable technique for quantifying expression levels of targeted genes during various biological processes in numerous areas of clinical and biological research. Selection of appropriate reference genes for RT-qPCR normalization is an elementary prerequisite for reliable measurements of gene expression levels. Here, by analyzing datasets published between 2008 and 2017, we summarized the current trends in reference gene selection for insect gene expression studies that employed the most widely used SYBR Green method for RT-qPCR normalization. We curated 90 representative papers, mainly published in 2013–2017, in which a total of 78 insect species were investigated in 100 experiments. Furthermore, top five journals, top 10 frequently used reference genes, and top 10 experimental factors have been determined. The relationships between the numbers of the reference genes, experimental factors, analysis tools on the one hand and publication date (year) on the other hand was investigated by linear regression. We found that the more recently the paper was published, the more experimental factors it tended to explore, and more analysis tools it used. However, linear regression analysis did not reveal a significant correlation between the number of reference genes and the study publication date. Taken together, this meta-analysis will be of great help to researchers that plan gene expression studies in insects, especially the non-model ones, as it provides a summary of appropriate reference genes for expression studies, considers the optimal number of reference genes, and reviews the average number of experimental factors and analysis tools per study.

Selection and evaluation of reference genes for expression analysis using quantitative real-time PCR in the Asian Ladybird Harmonia axyridis (Coleoptera: Coccinellidae)

Harmonia axyridis (Coleoptera: Coccinellidae) is a polyphagous insect that is an important biological agent used to control agricultural and forestry pests. The role of functional genes in H. axyridis based on quantitative real-time PCR (qRT-PCR) is increasingly well understood to investigate biology, physiology, feeding behavior and the role of important genes in physiological processes. Quantitative real-time PCR (qRT-PCR) is a powerful and reliable technique to quantify gene expression. Using qRT-PCR, expression levels of target genes are determined based on the levels of internal reference genes; therefore, reference genes need to be stably expressed under specific experimental conditions. However, there have been no studies on the stability of reference genes used in H. axyridis. In this study, we systematically investigated expression profiles of nine candidate reference genes from H. axyridis, including β-actin (ACTIN); elongation factor 1 α (EF1A); ribosomal proteins L10, L18, L28, S13, and S15 (RPL10, RPL18, RPL28, RPS13 and RPS15); glyceraldehyde-3-phosphate dehydrogenase (GAPDH); and superoxide dismutase (SOD). Four analytical methods (geNorm, BestKeeper, NormFinder, and the ΔCt method) were used to evaluate the suitability of these genes as internal reference genes for three biotic factors (developmental stage, tissue, and sex) and two abiotic treatments (temperature and photoperiod). RefFinder, a comprehensive evaluation platform integrating the four analytical methods, was used to rank the overall stability of these reference genes. Among the nine candidate genes, different reference genes were identified as having the most stable expression across biotic and abiotic factors. Genes encoding ribosomal proteins typically had the most stable expression, though EF1A was the most stable across developmental stages and photoperiods. To validate the suitability of these reference genes, heat shock protein 90 (HSP90) was chosen as a target. Significant up-regulation in HSP90 expression level in response to both low and high temperature was observed when using the most suitable reference genes but not when using an arbitrarily selected reference gene. The reference genes identified in this study will provide the basis for future functional genomics research in H. axyridis and will also facilitate the establishment of a standardized qRT-PCR program for other related insects.

Screening potential reference genes for quantitative real-time PCR analysis in the oriental armyworm, Mythimna separata

The oriental armyworm, Mythimna separata, is a major insect pest in China and other Asian countries. Unfortunately, suitable reference genes for quantitative real-time PCR (qRT-PCR) have not been previously identified in M. separata for normalizing target gene expression. In this study, we evaluated the expression stability of eight candidate genes (18S, ACT, EF1-α, GAPDH, RPS7, RPS13, RPL32 and TUB) in M. separata using the comparative ΔCt method, BestKeeper, Normfinder geNorm and ReFinder, a comprehensive software platform. The results indicated that the appropriate reference gene varied depending on the experimental conditions. We found that ACTIN, EF1-α and TUB were optimal for different developmental stages; TUB, RPS13 and EF1-α showed the most stable expresssion in different tissues; RPS13 and 18S were the best reference genes for monitoring expression under high temperature conditions; TUB, RPS13 and RPS7 exhibited the most stable expression under larval-crowding conditions; RPS7, EF1-α, RPL32 and GAPDH were the best for pesticide exposure experiments. This study provides tools for reliable normalization of qRT-PCR data and forms a foundation for functional studies of target gene expression in M. separata.

The Battle Against Flystrike - Past Research and New Prospects Through Genomics

Flystrike, or cutaneous myiasis, is caused by blow fly larvae of the genus Lucilia. This disease is a major problem in countries with large sheep populations. In Australia, Lucilia cuprina (Wiedemann, 1830) is the principal fly involved in flystrike. While much research has been conducted on L. cuprina, including physical, chemical, immunological, genetic and biological investigations, the molecular biology of this fly is still poorly understood. The recent sequencing, assembly and annotation of the draft genome and analyses of selected transcriptomes of L. cuprina have given a first global glimpse of its molecular biology and insights into host-fly interactions, insecticide resistance genes and intervention targets. The present article introduces L. cuprina, flystrike and associated issues, details past control efforts and research foci, reviews salient aspects of the L. cuprina genome project and discusses how the new genomic and transcriptomic resources for this fly might accelerate fundamental molecular research of L. cuprina towards developing new methods for the treatment and control of flystrike.

Urate Oxidase produced by Lucilia sericata medical maggots is localized in Malpighian tubes and facilitates allantoin production

Lucilia sericata maggots are the only species currently approved for maggot debridement therapy (MDT), an alternative treatment for chronic and recalcitrant wounds. Maggots promote wound debridement, disinfection and healing by producing a complex mixture of proteins, peptides and low-molecular-weight compounds in their secretions and excretions, but the individual components are not well characterized at the molecular level. Here we investigated the purine catabolism pathway in L. sericata, focusing on the production of allantoin by Urate Oxidase (UO), which is thought to promote wound healing. We produced recombinant L. sericata UO in Escherichia coli, and characterized the properties of the pure enzyme in terms of the optimum pH (7-10) and temperature (20-25 °C), its stability, sensitivity to inhibition and ion dependency. We used quantitative RT-PCR and RNA in situ hybridization to monitor the expression of the UO gene, and we used a guinea pig anti-UO antibody to detect the native enzyme by western blot and by florescence immunohistochemistry in larval tissues. We found that L. sericata UO is exclusively present in the larval excretion organ (the Malpighian tubes) and is freely available in the cytoplasm rather than restricted to a specific subcellular compartment. Allantoin is a final product of L. sericata purine catabolism. It is produced by UO in the Malpighian tubes to remove uric acid from the hemolymph and is consequently excreted via the hindgut. Our findings confirm the hypothesis that both actively secreted molecules and excretion products contribute to the beneficial effects of MDT.

Heat shock protein 83 plays pleiotropic roles in embryogenesis, longevity, and fecundity of the pea aphid Acyrthosiphon pisum

Heat shock protein 83 (HSP83) is homologous to the chaperone HSP90. It has pleiotropic functions in Drosophila melanogaster, including the control of longevity and fecundity, and facilitates morphological evolution by buffering cryptic deleterious mutations in wild populations. In the pea aphid Acyrthosiphon pisum, HSP83 expression is moderately induced by bacterial infection but upregulated more strongly in response to heat stress and fungal infection. Stress-inducible heat shock proteins are of considerable evolutionary and ecological importance because they are known to buffer environmental variation and to influence fitness under non-optimal conditions. To investigate the functions of HSP83 in viviparous aphids, we used RNA interference to attenuate its expression and studied the impact on complex parameters. The RNA interference (RNAi)-mediated depletion of HSP83 expression in A. pisum reduced both longevity and fecundity, suggesting this chaperone has an evolutionarily conserved function in insects. Surprisingly, HSP83 depletion reduced the number of viviparous offspring while simultaneously increasing the number of premature nymphs developing in the ovaries, suggesting an unexpected role in aphid embryogenesis and eclosion. The present study indicates that reduced HSP83 expression in A. pisum reveals both functional similarities and differences compared with its reported roles in holometabolous insects. Its impact on aphid lifespan, fecundity, and embryogenesis suggests a function that determines their fitness. This could be achieved by targeting different client proteins, recruiting distinct co-chaperones or transposon activation.

Seasonal phenotype-specific transcriptional reprogramming during metamorphosis in the European map butterfly Araschnia levana

The European map butterfly (Araschnia levana) is a classic example of seasonal polyphenism because the spring and summer imagoes display two distinct morphological phenotypes. The light regime and temperature during larval and prepupal development determine whether or not the pupae commit to diapause and overwintering and thus whether spring or summer imagoes emerge. We used suppression subtractive hybridization to experimentally screen for genes that are differentially expressed in prepupae committed either to accelerated metamorphosis and egg production or diapause and overwintering. The range and ontology of the differentially expressed genes in prepupae developing from larvae exposed either to long‐day (LD) or short‐day (SD) conditions revealed fundamental differences. The SD prepupae preferentially expressed genes related to cuticle formation and immunity, reflecting the formation of a robust pupal exoskeleton and the upregulation of antimicrobial peptides as preparations for overwintering. One protein preferentially expressed in SD prepupae has a counterpart in Bombyx mori that functions as a diapause duration clock. The differentially expressed genes in LD prepupae included several members of the dusky and osiris families. We also observed the strong induction of different yellow‐like genes under SD and LD conditions which suggest a role in the developmental choice between seasonal phenotypes. Our transcriptomic data will facilitate the more detailed analysis of molecular mechanisms underlying seasonal polyphenism.

Next Generation Sequencing Identifies Five Major Classes of Potentially Therapeutic Enzymes Secreted by Lucilia sericata Medical Maggots

Lucilia sericata larvae are used as an alternative treatment for recalcitrant and chronic wounds. Their excretions/secretions contain molecules that facilitate tissue debridement, disinfect, or accelerate wound healing and have therefore been recognized as a potential source of novel therapeutic compounds. Among the substances present in excretions/secretions various peptidase activities promoting the wound healing processes have been detected but the peptidases responsible for these activities remain mostly unidentified. To explore these enzymes we applied next generation sequencing to analyze the transcriptomes of different maggot tissues (salivary glands, gut, and crop) associated with the production of excretions/secretions and/or with digestion as well as the rest of the larval body. As a result we obtained more than 123.8 million paired-end reads, which were assembled de novo using Trinity and Oases assemblers, yielding 41,421 contigs with an N50 contig length of 2.22 kb and a total length of 67.79 Mb. BLASTp analysis against the MEROPS database identified 1729 contigs in 577 clusters encoding five peptidase classes (serine, cysteine, aspartic, threonine, and metallopeptidases), which were assigned to 26 clans, 48 families, and 185 peptidase species. The individual enzymes were differentially expressed among maggot tissues and included peptidase activities related to the therapeutic effects of maggot excretions/secretions.

A Jonah-like chymotrypsin from the therapeutic maggot Lucilia sericata plays a role in wound debridement and coagulation

Lucilia sericata larvae are used in maggot debridement therapy, a traditional wound healing approach that has recently been approved for the treatment of chronic wounds. Maggot excretion products (MEP) contain many different proteases that promote disinfection, debridement and the acceleration of wound healing, e.g. by activating the host contact phase/intrinsic pathway of coagulation. In order to characterise relevant procoagulant proteases, we analysed MEP and identified a chymotrypsin-like serine protease with similarities to Jonah proteases from Drosophila melanogaster and a chymotrypsin from Lucilia cuprina. A recombinant form of the L. sericata Jonah chymotrypsin was produced in Escherichia coli. The activated enzyme (Jonahm) had a pH optimum of 8.0 and a temperature optimum of 37 °C, based on the cleavage of the chromogenic peptide s-7388 and casein. Jonahm reduced the clotting time of human plasma even in the absence of the endogenous protease kallikrein, factor XI or factor XII and digested the extracellular matrix proteins fibronectin, laminin and collagen IV, suggesting a potential mechanism of wound debridement. Based on these characteristics, the novel L. sericata chymotrypsin-like serine protease appears to be an ideal candidate for the development of topical drugs for wound healing applications.

Evaluating Sarconesiopsis magellanica blowfly-derived larval therapy and comparing it to Lucilia sericata-derived therapy in an animal model

Larval therapy is used as alternative treatment for hard-to-heal chronic and infected wounds. Lucilia sericata is the most used blowfly species. However, it has been shown recently that Sarconesiopsis magellanica larval excretions and secretions have potent antibacterial activity; this blowfly belongs to the Calliphoridae family. The present work has dealt with evaluating larval therapy using S. magellanica on wounds induced in diabetic rabbits and its action was compared to the effect induced by L. sericata. Twelve New Zealand White rabbits (Oryctolagus cuniculus) were used; they were divided into 4 groups, the first two being treated with larval therapy derived from both aforementioned necrophagous blowflies, an antibiotic was used in the third and the fourth was used as control. All the animals were wounded on the back and infected with Pseudomonas aeruginosa and Staphylococcus aureus. Samples of the secretion from each animal's infected wound were taken and sown on blood agar. The colony forming units were then counted. The PUSH scale was used for the macroscopic evaluation of the wounds. Bacterial control was encountered 48 h post-treatment in the treatments involving larval therapy and to a lesser extent with the antibiotic. Likewise, wound debridement was quicker and more efficient with larval therapy compared to the antibiotic group; however, wound closing time was 23 days in all treatments. The group treated with S. magellanica larvae had relatively quicker evolution until the proliferation phase and the start of maturation, even though there were no significant differences between both blowfly species evaluated here regarding treatments by the end of the treatment period. The present study has validated the diabetic rabbit model for inducing chronic wounds regarding larval therapy and has likewise confirmed the effectiveness of S. magellanica-derived larval therapy as an alternative for curing and healing wounds.