Bacterial ghosts presenting fertility proteins for induction of immunocontraception in possum

Ziel dieser vorliegenden Arbeit war die Produktion eines immunocontrazeptiven Impfstoffes auf Basis des Bacterial Ghost Systems, um die Opossum (Trichosurus vulpecula) Wildpopulation Neuseelands einzudämmen. Für die Herstellung eines fertilitätskontrollierenden Impfstoffes wurden zunächst vier unterschiedliche Ziel-Sequenzen ausgewählt: ZP2C, Zona Pellucida Protein 2, C-terminale Sequenz ZP2Copt, Zona Pellucida Protein, mit optimiertem Codon für E. coli Expression Cp4, Coat Protein 4 des Conceptus Vap1, Vesicle Associated Protein 1 der frühen Oogenese Die vier oben genannten immunologischen Sequenzen wurden in E. coli produziert, wobei die jeweilige Ziel-Sequenz in den periplasmatischen Raum transportiert wurde. Anschließend wurden die Bakterien durch E-gesteuerte Lyse in Bacterial Ghosts überführt. BG-Impfstoffe, stimulieren auf natürliche Weise das Immunsystem, ohne dass weitere Adjuvanten benötigt werden. Durch die Anwendung der sogenannten Impfstoffe in Opossums soll das Immunsystem der Tiere angeregt werden um eine humorale sowie zelluläre Immunantwort gegen die verwendeten Ziel-Proteine zu induzieren

Delivery of a Chlamydial Adhesin N-PmpC Subunit Vaccine to the Ocular Mucosa Using Particulate Carriers

Trachoma, caused by the intracellular bacterium Chlamydia trachomatis (Ct), remains the world's leading preventable infectious cause of blindness. Recent attempts to develop effective vaccines rely on modified chlamydial antigen delivery platforms. As the mechanisms engaged in the pathology of the disease are not fully understood, designing a subunit vaccine specific to chlamydial antigens could improve safety for human use. We propose the delivery of chlamydia-specific antigens to the ocular mucosa using particulate carriers, bacterial ghosts (BGs). We therefore characterized humoral and cellular immune responses after conjunctival and subcutaneous immunization with a N-terminal portion (amino acid 1-893) of the chlamydial polymorphic membrane protein C (PmpC) of Ct serovar B, expressed in probiotic Escherichia coli Nissle 1917 bacterial ghosts (EcN BGs) in BALB/cmice. Three immunizations were performed at two-week intervals, and the immune responses were evaluated two weeks after the final immunization in mice. In a guinea pig model of ocular infection animals were immunized in the same manner as the mice, and protection against challenge was assessed two weeks after the last immunization. N-PmpC was successfully expressed within BGs and delivery to the ocularmucosa was well tolerated without signs of inflammation. N-PmpC- specific mucosal IgA levels in tears yielded significantly increased levels in the group immunized via the conjunctiva compared with the subcutaneously immunized mice. Immunization with N-PmpC EcN BGs via both immunization routes prompted the establishment of an N-PmpC-specific IFN gamma immune response. Immunization via the conjunctiva resulted in a decrease in intensity of the transitional inflammatory reaction in conjunctiva of challenged guinea pigs compared with subcutaneously and non-immunized animals. The delivery of the chlamydial subunit vaccine to the ocular mucosa using a particulate carrier, such as BGs, induced both humoral and cellular immune responses. Further investigations are needed to improve the immunization scheme and dosage

Donor-Control of Scavenging Food Webs at the Land-Ocean Interface.

Food webs near the interface of adjacent ecosystems are potentially subsidised by the flux of organic matter across system boundaries. Such subsidies, including carrion of marine provenance, are predicted to be instrumental on open-coast sandy shores where in situ productivity is low and boundaries are long and highly permeable to imports from the sea. We tested the effect of carrion supply on the structure of consumer dynamics in a beach-dune system using broad-scale, repeated additions of carcasses at the strandline of an exposed beach in eastern Australia. Carrion inputs increased the abundance of large invertebrate scavengers (ghost crabs, Ocypode spp.), a numerical response most strongly expressed by the largest size-class in the population, and likely due to aggregative behaviour in the short term. Consumption of carrion at the beach-dune interface was rapid and efficient, driven overwhelmingly by facultative avian scavengers. This guild of vertebrate scavengers comprises several species of birds of prey (sea eagles, kites), crows and gulls, which reacted strongly to concentrations of fish carrion, creating hotspots of intense scavenging activity along the shoreline. Detection of carrion effects at several trophic levels suggests that feeding links arising from carcasses shape the architecture and dynamics of food webs at the land-ocean interface

Vertebrate scavengers on the beach.

<p>a) Brahminy kite consuming a mullet; b) Whistling kite gripping a fish; c & d) White-bellied sea eagle starting to lift a fish carcass off the beach; e) Lace monitor approaching carrion; f) Red fox at an experimental plot containing fish carcasses.</p

Temporal distribution of scavenging activity in experimental plots by the six vertebrate consumers recorded.

<p>Sunrise was close to 06:00 and sunset close to 18: 00 during the experiment (U2 is the test statistics for Watson’s test of circular uniformity; *** p < 0.001).</p

Density response to experimental augmentation of fish carcasses by different size classes of ghost crabs.

<p>Measure of organism size is the burrow opening diameter of ghost crabs. The metric of density change is the ratio of mean densities per plot before and after the addition of carrion (i.e., response ratio = mean ind. m^-2 plot_i size-class_x BEFORE) / mean ind. m^-2 plot_i size-class_x AFTER). Letters denote homogeneous groups as defined by SNK post-hoc testing following significant main effects in ANOVA. Boxes encompass the interquartile range (Q1 to Q3) and whiskers are the 10^th and 90^th percentile.</p

Comparison of the density (mean, SE) of ghost crabs before (open bars) and during (filled bars) the experimental augmentation of carrion availability.

<p>Fish carcasses were added to treatment plots only during the ‘carrion pulse’ phase of the experiment.</p

Aggregative responses of avian scavengers to fish carcasses at the beach-dune interface.

<p>a & b) Mixed flock of two brahminy kites and three whistling kites feeding on fish carrion in an area of approximately 3 x 10 m; b) Torresian crow reacting to freshly-deposited fish carrion; c & d) flocks of crows and silver gulls amassing around fish carrion; f) mixed flock of avian scavengers, with a white-bellied sea eagle amongst crows and gulls.</p

Comparison of species richness (top panel) and abundance of vertebrate scavengers between experimental plots to which fish carcasses were added (treatment) and in unaltered plots (‘control’).

<p>The measure of abundance is the mean number of individuals recorded per 24 h of camera deployment.</p