Observations on the glycosylation of the term placenta of the Indo-Pacific Bottlenose Dolphin (Tursiops aduncus): A lectin histochemical study.

INTRODUCTION: Little is known about the glycosylation of placental villi and areolae of cetaceans. Term tissue from the delivered placenta of an Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) was examined using lectin histochemistry to compare trophoblast glycosylation in these two locations. METHODS: Placental blocks fixed in 10% formalin were resin-embedded before semithin sections were stained with 24 biotinylated lectins and an avidin-biotin revealing system. RESULTS: Areolar trophoblast was composed of large, bulbous cells packed with numerous granules compared to the smaller, cuboidal cells clothing the chorionic villi, which had a sparser, mainly subapical granule population. Both were richly glycosylated; generally areolar cells were more heavily stained apart from poor binding to some N-acetylgalactosamine and N-acetylglucosamine termini. Most striking was the distribution of α1,2-linked fucosyl residues, weakly expressed in villous trophoblast but intensely stained in some areolar cells, also terminal sialic acids. Some lectins bound in a variable fashion. Staining of terminal α-d-mannose, which locates mainly to lysosomes, was heavy in areolar cells compared to scattered irregular foci in villous cells. DISCUSSION AND CONCLUSION: The many intracellular inclusions reflect ongoing lysosomal breakdown of histotroph in areolar cells which often show heterogeneous glycosylation staining unlike the uniformly stained villous cells, possibly reflecting partial breakdown of ingested sialoglycoprotein, cell turnover or regional variation in uptake of histotroph. Our results indicate that Dolphin areolae are functionally distinct from villous trophoblast, performing absorptive and phagocytic functions similar to other Artiodactyla.

Erysipelas vaccination protocols in dolphins Tursiops truncatus evaluated by antibody responses over twenty continuous years.

Erysipelas is an infection caused by Erysipelothrix rhusiopathiae that affects many different species around the world, including cetaceans. The acute septicemic form can rapidly cause death in bottlenose dolphins Tursiops truncatus. The ultimate goals of this long-term study were the development and identification of the most effective vaccination protocol against clinical erysipelas in T. truncatus using a commercially available swine vaccine, and to determine whether there is a need for a semi-annual vaccination versus an annual vaccination. The present study concentrated on the immunization of a dolphin population (7 wild-born and 22 captive-born individuals) with 2 swine vaccines, the European 'Eurovac Ery®' vaccine and the American 'ER Bac Plus®' vaccine, and immunological profile results over a 20-yr time period. The general protocol was a primo-vaccination (between 3 and 7 mo of age for calves) with or without a booster 1 mo post primo-vaccination and either annual or semi-annual vaccination thereafter. Sera were collected prior to vaccination, 2 wk post-vaccination and monthly. A dolphin-specific ELISA was developed to analyze the erysipelas-specific antibody response of vaccinated animals. The final ELISA results (n = 1362 samples from 29 animals at pre- and post-vaccination time) suggest that (1) there is a significant difference in antibody levels at the start of the vaccination between older and younger animals; (2) at least 3 vaccinations are necessary to obtain antibody levels above the levels at pre-vaccination; (3) thereafter, annual vaccinations seem sufficient to keep antibody levels above the levels at pre-vaccination; and (4) both vaccines induced similar responses. No case of erysipelas infection was observed in this population during the study.

Genomic characterization of novel dolphin papillomaviruses provides indications for recombination within the Papillomaviridae.

Phylogenetic analysis of novel dolphin (Tursiops truncatus) papillomavirus sequences, TtPV1, -2, and -3, indicates that the early and late protein coding regions of their genomes differ in evolutionary history. Sliding window bootscan analysis showed a significant a change in phylogenetic clustering, in which the grouped sequences of TtPV1 and -3 move from a cluster with the Phocoena spinipinnis PsPV1 in the early region to a cluster with TtPV2 in the late region. This provides indications for a possible recombination event near the end of E2/beginning of L2. A second possible recombination site could be located near the end of L1, in the upstream regulatory region. Selection analysis by using maximum likelihood models of codon substitutions ruled out the possibility of intense selective pressure, acting asymmetrically on the viral genomes, as an alternative explanation for the observed difference in evolutionary history between the early and late genomic regions of these cetacean papillomaviruses.