Expression of the rubber-like protein, resilin, in developing and functional insect cuticle determined using a Drosophila anti-Rec 1 resilin antibody.

BACKGROUND: The natural elastomeric protein, insect resilin, is the most efficient elastic material known, used to store energy for jumping and flight in a variety of insects. Here, an antibody to recombinant Drosophila melanogaster pro-resilin is used to examine resilin expression in Drosophila and a wider range of insects. RESULTS: Immunostaining of Drosophila embryos reveals anti-resilin reactivity in epidermal patches that exhibit a dynamic spatial and temporal expression through late embryogenesis. Resilin is also detected in stretch receptors in the embryo. In developing adult Drosophila, resilin pads are described at the base of wings and at the base of flexible sensory hairs in pupae. Resilin is also detected in embryos of the tephritid fruitfly, Bactrocera tryoni, and two well-known concentrations of insect resilin: the flight muscle tendon of the dragonfly and the pleural arch of the flea. CONCLUSIONS: The anti-Rec1 antibody antibody developed using Drosophila pro-resilin as antigen is cross-reactive and is useful for detection of resilin in diverse insects. For the first time, resilin expression has been detected during embryogenesis, revealing segmental patches of resilin in the developing epidermis of Drosophila.

Glycosylation of gp116 and gp64 envelope proteins of yellow head virus of Penaeus monodon shrimp.

Yellow head virus (YHV) is a highly virulent pathogen of Penaeus monodon shrimp that is classified in the genus Okavirus, family Roniviridae, in the order Nidovirales. Separation of virion proteins treated with peptide-N-glycosidase-F (PNGase-F) in SDS-polyacrylamide gels and the use of glycoprotein-specific staining methods indicated that the gp116 and gp64 envelope glycoproteins possess N-linked rather than O-linked glycans. Competitive binding inhibition of lectins with various oligosaccharide specificities indicated that glycans linked to gp64 are mannose-rich, whilst glycans linked to gp116 possess terminal N-acetylgalactosamine and N-acetylglucosamine in addition to terminal mannose-type sugars. Mass spectrometry analyses of peptides generated from YHV proteins before and after deglycosylation with PNGase-F, using combinations of the endoproteinases trypsin, Asp-N and Lys-C, confirmed occupancy of six of the seven potential N-linked glycosylation sites in gp116 and three of the four potential sites in gp64.

Identification of immune genes and proteins involved in the response of bovine mammary tissue to Staphylococcus aureus infection.

BACKGROUND: Mastitis in dairy cattle results from infection of mammary tissue by a range of micro-organisms but principally coliform bacteria and Gram positive bacteria such as Staphylococcus aureus. The former species are often acquired by environmental contamination while S. aureus is particularly problematic due to its resistance to antibiotic treatments and ability to reside within mammary tissue in a chronic, subclinical state. The transcriptional responses within bovine mammary epithelial tissue subjected to intramammary challenge with S. aureus are poorly characterised, particularly at the earliest stages of infection. Moreover, the effect of infection on the presence of bioactive innate immune proteins in milk is also unclear. The nature of these responses may determine the susceptibility of the tissue and its ability to resolve the infection. RESULTS: Transcriptional profiling was employed to measure changes in gene expression occurring in bovine mammary tissues sampled from three dairy cows after brief and graded intramammary challenges with S. aureus. These limited challenges had no significant effect on the expression pattern of the gene encoding beta-casein but caused coordinated up-regulation of a number of cytokines and chemokines involved in pro-inflammatory responses. In addition, the enhanced expression of two genes, S100 calcium-binding protein A12 (S100A12) and Pentraxin-3 (PTX3) corresponded with significantly increased levels of their proteins in milk from infected udders. Both genes were shown to be expressed by mammary epithelial cells grown in culture after stimulation with lipopolysaccharide. There was also a strong correlation between somatic cell count, a widely used measure of mastitis, and the level of S100A12 in milk from a herd of dairy cows. Recombinant S100A12 inhibited growth of Escherichia coli in vitro and recombinant PTX3 bound to E. coli as well as C1q, a subunit of the first component of the complement cascade. CONCLUSION: The transcriptional responses in infected bovine mammary tissue, even at low doses of bacteria and short periods of infection, probably reflect the combined contributions of gene expression changes resulting from the activation of mammary epithelial cells and infiltrating immune cells. The secretion of a number of proinflammatory cytokines and chemokines from mammary epithelial cells stimulated by the bacteria serves to trigger the recruitment and activation of neutrophils in mammary tissue. The presence of S100A12 and PTX3 in milk from infected udder quarters may increase the anti-bacterial properties of milk thereby helping to resolve the mammary tissue infection as well as potentially contributing to the maturation of the newborn calf epithelium and establishment of the newborn gut microbial population.

A pair of adjacent genes, cry5Ad and orf2-5Ad, encode the typical N- and C-terminal regions of a Cry5Adelta-endotoxin as two separate proteins in Bacillus thuringiensis strain L366.

A new DNA sequence cry5Ad/orf2-5Ad (GenBank accession number EF219060) was isolated from Bacillus thuringiensis strain L366. This DNA sequence contains two ORFs: cry5Ad (a previously unreported member of the cry5A gene family) and orf2-5Ad. cry5Ad is unique among cry5A genes in that it encodes only the N-terminal region of a typical Cry5Adelta-endotoxin. The cry5Ad sequence includes homology blocks 1-5, which are present in most B. thuringiensisdelta-endotoxins. The usual C-terminal region of a Cry5Adelta-endotoxin (including homology blocks 6-8) is encoded by orf2-5Ad. Both proteins encoded by cry5Ad and orf2-5Ad were found in IPTG-induced Escherichia coli, after a copy of cry5Ad/orf2-5Ad was cloned into the pQE32 expression vector and transformed into pREP4 E. coli cells. Both proteins were also found in parasporal crystal inclusions of B. thuringiensis L366. Sequencing of cDNA derived from transformed E. coli cells showed that the two ORFs are transcribed as a single mRNA. Extracts prepared from the recombinant E. coli expressing Cry5Ad and Orf2-5Ad were not toxic to nematode larvae (Haemonchus contortus), indicating that these two proteins are most likely not responsible for the nematocidal activity seen previously in the B. thuringiensis strain L366.

Design and facile production of recombinant resilin-like polypeptides: gene construction and a rapid protein purification method.

Resilin is an elastic protein found in specialized regions of the cuticle of insects, which displays unique resilience and fatigue lifetime properties. As is the case with many elastomeric proteins, including elastin, gliadin and spider silks, resilin contains distinct repetitive domains that appear to confer elastic properties to the protein. Recent work within our laboratory has demonstrated that cloning and expression of exon 1 of the Drosophila melanogaster CG15920 gene, encoding a putative resilin-like protein, results in a recombinant protein that can be photochemically crosslinked to form a highly resilient, elastic biomaterial (Rec1 resilin). The current study describes a recursive cloning strategy for generating synthetic genes encoding multiple copies of consensus polypeptides, based on the repetitive domains within resilin-like genes from D. melanogaster and Anopheles gambiae. A simple non-chromatographic purification method that can be applied to these synthetic proteins and Rec1 is also reported. These methods for the design and purification of resilin-like periodic polypeptides will facilitate the future investigation of structural and functional properties of resilin, and the development of novel highly resilient biomaterials.

Synthesis and properties of crosslinked recombinant pro-resilin.

Resilin is a member of a family of elastic proteins that includes elastin, as well as gluten, gliadin, abductin and spider silks. Resilin is found in specialized regions of the cuticle of most insects, providing low stiffness, high strain and efficient energy storage; it is best known for its roles in insect flight and the remarkable jumping ability of fleas and spittle bugs. Previously, the Drosophila melanogaster CG15920 gene was tentatively identified as one encoding a resilin-like protein (pro-resilin). Here we report the cloning and expression of the first exon of the Drosophila CG15920 gene as a soluble protein in Escherichia coli. We show that this recombinant protein can be cast into a rubber-like biomaterial by rapid photochemical crosslinking. This observation validates the role of the putative elastic repeat motif in resilin function. The resilience (recovery after deformation) of crosslinked recombinant resilin was found to exceed that of unfilled synthetic polybutadiene, a high resilience rubber. We believe that our work will greatly facilitate structural investigations into the functional properties of resilin and shed light on more general aspects of the structure of elastomeric proteins. In addition, the ability to rapidly cast samples of this biomaterial may enable its use in situ for both industrial and biomedical applications.

Identification and characterization of proteins from Bacillus thuringiensis with high toxic activity against the sheep blowfly, Lucilia cuprina.

Current control of the sheep blowfly (Lucilia cuprina) relies on chemical insecticides, however, with the development of resistance and increasing concerns about human health and environmental residues, alternative strategies to control this economically important pest are required. In this study, we have identified several isolates of Bacillus thuringiensis (Bt), collected from various Australian soil samples, that produce crystals containing 130 and 28 kDa proteins. These isolates were highly toxic to feeding larvae in both in vitro bioassays and in vivo on sheep. By N-terminal amino acid sequencing, we identified the smaller crystal band (28 kDa) as a cytological (Cyt) protein. Upon solubilization and proteolytic processing by trypsin, the 130 kDa crystal protein yielded among others, a truncated 55-60 kDa toxin moiety which exhibited larvicidal activity against sheep blowfly. The amino-terminal sequence of the trypsin-resistant protein band revealed that this Bt endotoxin was encoded by a new cry gene. The novel cry protein was present in all the strains that were highly toxic in the larval assay. We have also identified from one of the isolates, a novel secretory toxin with larvicidal activity.