Molecular tracing of white muscardine in the silkworm, Bombyx mori (Linn.) II. Silkworm white muscardine is not caused by artificial release or natural epizootic of Beauveria bassiana in China

Bombyx batryticatus extract activates coagulation factor Ⅻ to promote angiogenesis in rats with cerebral ischemia/reperfusion injury

ETHNOPHARMACOLOGICAL RELEVANCE

Bombyx batryticatus is traditionally used to treat patients with stroke, but its mechanism remains unclear.

AIM OF THE STUDY

To explore the interventional effect of Bombyx batryticatus extract as an activator of FⅫ on angiogenesis of rats with cerebral ischemia/reperfusion injury.

MATERIALS AND METHODS

Firstly, the mechanism of Bombyx batryticatus interfering with IS was predicted by systematic pharmacology method, and then it was further verified by animal experiments. The effects of Bombyx batryticatus extract on plasma coagulation were detected, and the activation of coagulation factor Ⅻ (FⅫ) and its downstream substrate kallikrein kinase (KK) was detected in vitro. The brain morphology and expressions of FXII, KK, vascular endothelial growth factors (VEGF), CD31, Brdu/von Willebrand Factor (vWF) were detected. The morphological changes, cell proliferation and VEGF expression of brain microvascular endothelial cells were detected by oxygen glucose deprivation model. The pharmacodynamic substances of Bombyx batryticatus extract were identified by Liquid Chromatography - Mass Spectrometry (LC-MS).

RESULTS

The results of systematic pharmacology found that the treatment of IS by Bombyx batryticatus may be related to blood coagulation and other processes. In vitro, Bombyx batryticatus extract prolonged the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) (P < 0.05), activated FⅫ and promoted the production of downstream substrate KK, with dose-dependent (P < 0.05). Bombyx batryticatus extract improved the neuronal damage of rats, activated FXII and increased the production of KK and the expressions of VEGF, CD31, Brdu/vWF (P < 0.05). Bombyx batryticatus extract also increased the proliferation of brain microvascular endothelial cells and expression of VEGF in rats (P < 0.05). A total of 809 metabolites in Bombyx batryticatus extract were identified by LC-MS.

CONCLUSION

Bombyx batryticatus extract may ameliorate the injury of nerve function in rats with cerebral ischemia/reperfusion injury.

First Record of Beauveria varroae, Cordyceps blackwelliae, and Purpureocillium lavendulum from Greece and Their Pathogenicity against Thaumetopoea pityocampa

Entomopathogenic fungi (EPF) consist of a wide range of fungi that can be used as pest control agents, endophytes, and plant growth promoters. In this study of EPF in suburban soils from Achaia, Greece, we used adult beetles as baits for trapping fungal isolates. According to the macroscopic and microscopic traits of the collected isolates, three species corresponded to Beauveria varroae Vuill. (Hypocreales: Cordycipitaceae); Purpureocillium lavendulum Perdomo, Gené, Cano & Guarro (Hypocreales: Ophiocordycipitaceae); and Cordyceps blackwelliae Mongkolsamrit, Noisripoom, Thanakitpipattana, Spatafora & Luangsaard (Hypocreales: Claviceptaceae). Their taxonomic identity was established by ITS-rDNA sequence amplification and sequencing, molecular database comparisons, and phylogenetic analysis. The application of these new EPF species clearly demonstrated remarkable insecticidal action on Thaumetopoea pityocampa (Lepidoptera, Notodontidae) larvae, which increased with the application dose. Our findings are important based on the enhancement of the application of new EPF species as biocontrol agents within the framework of eco-friendly pest management.

iTRAQ-based quantitative proteomic analysis of silkworm infected with Beauveria bassiana

Beauveria bassiana is a harmful pathogen to the economically important insect silkworm, always causes serious disease to the silkworm, which results in great losses to the sericulture industry. In order to explore the silkworm (Bombyx mori) response to B. bassiana infection, differential proteomes of the silkworm responsive to B. bassiana infection were identified with isobaric tags for relative and absolute quantitation (iTRAQ) at the different stage of the 3rd instar silkworm larvae. Among the 5040 proteins identified with confidence level of ≥95 %, total 937 proteins were differentially expressed, of which 488 proteins were up-regulated and 449 proteins were down-regulated. 23, 15, 250, 649 differentially expressed proteins (DEPs) were reliably quantified by iTRAQ analysis in the B. bassiana infected larvae at 18, 24, 36, 48 h post infection (hpi) respectively. Based on GO annotations, 6, 4, 128, 316 DEPs were involved in biological processes, 12, 5, 143, 376 DEPs were involved in molecular functions, and 6, 3, 108, 256 DEPs were involved in cell components at 18, 24, 36, 48 hpi respectively. KEGG pathway analysis displayed that 18, 12, 210, 548 DEPs separately participated in 63, 35, 201, 264 signal transduction pathways at different time of infection, and moreover a higher proportion of DEPs involved in metabolic pathways. The cluster analysis on the DEPs of different infection stages distinguished a co-regulated DEP, lysozyme precursor, which was up-regulated at both the mRNA level and the protein level, indicating that the lysozyme protein kept playing an important role in defending the silkworm against B. bassiana infection. This was the first report using an iTRAQ approach to analyze proteomes of the whole silkworm against B. bassiana infection, which contributes to better understanding the defense mechanisms of silkworm to B. bassiana infection and provides important experimental data for the identification of key factors involved in the interaction between the pathogenic fungus and its host.

Morphology, molecular characterization, and virulence of Beauveria pseudobassiana isolated from different hosts

Beauveria pseudobassiana has great potential for use in the management of various insect pests. In the present study, we aimed to explore the the virulence of B. pseudobassiana isolated from a diversity of hosts to Bombyx mori and Tenebrio molitor larvae. To this end, 15B. pseudobassiana isolates from 10 different geographical locations were identified based on morphological characteristics and molecular data. The phylogenetic positions of the isolates were evaluated according to morphological features and phylogenetic inferences based on six loci (nrSSU, nrLSU, TEF, RPB1, RPB2 and Bloc). In addition to growth in soil, the B. pseudobassiana isolates in our study were isolated from a wide host range that extended to 5 orders, 11 families, and 14 species. Moreover, anamorphically typified B. pseudobassiana was grown for the first time from teleomorph stromata. Pathogenicity of the B. pseudobassiana isolates from the different hosts was determined with two bioassays using B. mori and T. molitor larvae. The results indicated that mortality of B. mori caused by the lepidopteran isolates was significantly higher than that of isolates from other hosts, and virulence of the coleopteran isolates to T. molitor was significantly higher than that of isolates from other hosts. The host specificity of B. pseudobassiana should be studied in more detail before future consideration of isolates for use in biological control of pests.

Molecular Cloning, Bioinformatic Analysis, and Expression of Bombyx mori Lebocin 5 Gene Related to Beauveria bassiana Infection

A full-length cDNA of lebocin 5 (BmLeb5) was first cloned from silkworm, Bombyx mori, by rapid amplification of cDNA ends. The BmLeb5 gene is 808 bp in length and the open reading frame encodes a 179-amino acid hydroxyproline-rich peptide. Bioinformatic analysis results showed that BmLeb5 owns an O-glycosylation site and four RXXR motifs as other lebocins. Sequence similarity and phylogenic analysis results indicated that lebocins form a multiple gene family in silkworm as cecropins. Quantitative real-time PCR analysis revealed that BmLeb5 was highest expressed in the fat body. In the silkworm larvae infected by Beauveria bassiana, the expression level of BmLeb5 was upregulated in the fat body and hemolymph which are the most important immune tissues in silkworm. The recombinant protein of BmLeb5 was for the first time successfully expressed with prokaryotic expression system and purified. There are no reports so far that the expression of lebocins could be induced by entomopathogenic fungus. Our study suggested that BmLeb5 might play an important role in the immune response of silkworm to defend B. bassiana infection. The results also provided helpful information for further studying the lebocin family functioned in antifungal immune response in the silkworm.