Project description:Zygaenoidea is a superfamily of lepidopterans containing many venomous species, including the Limacodidae (nettle caterpillars) and Megalopygidae (asp caterpillars). Venom proteomes have been recently documented for several species from each of these families, but further data are required to understand the evolution of venom in Zygaenoidea. In this study, we examined the 'electric' caterpillar from North-Eastern Australia, a limacodid caterpillar densely covered in venomous spines. We used DNA barcoding to identify this caterpillar as the larva of the moth Comana monomorpha (Turner, 1904). We report the clinical symptoms of C. monomorpha envenomation, which include acute pain and erythema and oedema lasting for more than a week. Combining transcriptomics of venom spines with proteomics of venom harvested from the spine tips revealed a venom markedly different in composition from previously examined limacodid venoms that are rich in peptides. In contrast, the venom of C. monomorpha is rich in aerolysin-like proteins similar to those found in venoms of asp caterpillars (Megalopygidae). Consistent with this composition, the venom potently permeabilises sensory neurons and human neuroblastoma cells. This study highlights the diversity of venom composition in Limacodidae.
Project description:Callogenesis, the process during which explants derived from differentiated plant tissues are subjected to a de-differentiation step characterized by the proliferation of an unorganized mass of cells, is fundamental to indirect organogenesis and the establishment of cell suspension cultures. There-fore, understanding how callogenesis takes place is helpful to plant tissue culture, as well as to plant biotechnology and bioprocess engineering. The common herbaceous plant stinging nettle (Urtica dioica L.) is a species producing cellulosic fibres (the bast fibres) and a whole array of phytochemicals of pharmacological and cosmeceutical use. It is thus of interest as a potential multi-purpose plant. In this study, callogenesis in internode explants of a nettle fibre clone (clone 13) was studied using RNA-Seq to understand which gene ontologies predominate at different time points. Callogenesis was induced with the plant growth regulators α-napthaleneacetic acid (NAA) and 6-benzyl aminopurine (BAP) after having determined their optimal concentrations. The process was studied over a period of 34 days, time point at which a well visible callus mass developed on the explants. The bioinformatic analysis of the transcriptomic dataset revealed specific gene ontologies charac-terizing each of the four time points investigated (0, 1, 10 and 34 days-D). The results show that while the advanced stage of callogenesis is characterized by the iron deficiency response triggered by the high levels of reactive oxygen species accumulated by the proliferating cell mass, the intermediate and early phases are dominated by ontologies related to immune response and cell wall loosening, respectively.
Project description:To study the alteration pattern and defensive response mechanism triggered by herbivorous feeding stimuli under natural conditions, we built a biological model of the interrelationship between the Chinese pine (Pinus tabuliformis Carr.) and the Chinese pine caterpillar (Dendrolimus tabulaeformis Tsai et Liu) within their native habitat. We integrated proteomic and phosphoproteomic data, normalized the results, and combined them with bioinformatics to evaluate and analyze variations in phosphoproteomics in pine needles' response to the caterpillar's feeding stimulus. We systematically identified differentially significant phosphorylated proteins implicated in the pine's defense mechanism against caterpillar stress. Furthermore, we predicted upstream kinases of phosphorylation sites and their activities. Similarly, through an analysis of the Motif patterns of phosphorylated proteins, Mfuzz clustering of phosphorylation sites, kinase regulatory networks and functional modules of phosphorylated protein interaction networks in response to stress within pine, we can investigate the mechanisms behind resistance formation and regulation of caterpillar feeding incentives in pine. The identification results of partially phosphorylated proteins were additionally confirmed through PRM technology. Furthermore, genes upstream of differentially expressed proteins were validated through RT-qPCR detection.
Project description:Mycotoxins are secondary metabolites which are produced by numerous fungi and pose a continuous challenge to the safety and quality of food commodities in South Africa. These toxins have toxicologically relevant effects on humans and animals that eat contaminated foods. In this study, a diagnostic DNA microarray was developed for the identification of the most common food-borne fungi, as well as the genes leading to toxin production. A total of 40 potentially mycotoxigenic fungi isolated from different food commodities, as well as the genes that are involved in the mycotoxin synthetic pathways, were analyzed. For fungal identification, oligonucleotide probes were designed by exploiting the sequence variations of the elongation factor 1-alpha (EF-1 alpha) coding regions and the internal transcribed spacer (ITS) regions of the rRNA gene cassette. For the detection of fungi able to produce mycotoxins, oligonucleotide probes directed towards genes leading to toxin production from different fungal strains were identified in data available in the public domain. The probes selected for fungal identification and the probes specific for toxin producing genes were spotted onto microarray slides. The diagnostic microarray developed can be used to identify single pure strains or cultures of potentially mycotoxigenic fungi as well as genes leading to toxin production in both laboratory samples and maize-derived foods offering an interesting potential for microbiological laboratories. Keywords: Development of a diagnostic microarray for the identification of potentially mycotoxigenic fungi as well as genes leading to toxin production, 40 food-borne fungi, mycotoxins
Project description:Vibrio vulnificus is an foodborne pathogen that can cause gastroenteritis and septicemia in humans. V. vulnificus secretes a multifunctional autoprocessing repeats-in-toxin (MARTX) toxin as an essential virulence factor to cause disease. MARTX toxins are pore-forming toxins that translocate multiple functionally independent effector domains into a target cell. MARTX toxins of V. vulnificus can contain anywhere from 3 to 5 of the 10 identified effector domains and strains with different effector repertories having varying virulence potential. The goal of this study was to compare how different effector combinations from an F-type MARTX toxin differentially remodel the transcriptional response of human intestinal epithelial cells (IECs). F-type MARTX toxins contain five effector domains – the actin crosslinking domain (ACD), two copies the makes caterpillar floppy-like domain (MCF), and alpha-beta hydrolase (ABH) domain, and the Ras/Rap1 specific endopeptidase (RRSP). Cultured human IECs were treated with V. vulnificus or strains modified to secrete a toxin with only ACD, ACD with MCF-ABH, ACD with RRSP, or no active effectors. We demonstrate that when no active effectors are present, the bacterium induces minimal changes in the transcriptional profile of IECs. However, the strains containing different effector combinations each uniquely remodeled the transcriptional profile of IECs. These data provide insight into how V. vulnificus strains with varying effector combinations can differentially regulate the host cell response to cause disease.