Multiple Symbiodinium Strains Are Hosted by the Brazilian Endemic Corals Mussismilia spp.

Corals of genus Mussismilia (Mussidae) are one of the oldest extant clades of scleractinians. These Neogene relicts are endemic to the Brazilian coast and represent the main reef-building corals in the Southwest Atlantic Ocean (SAO). The relatively low-diversity/high-endemism SAO coralline systems are under rapid decline from emerging diseases and other local and global stressors, but have not been severely affected by coral bleaching. Despite the biogeographic significance and importance for understanding coral resilience, there is scant information about the diversity of Symbiodinium in this ocean basin. In this study, we established the first culture collections of Symbiodinium from Mussismilia hosts, comprising 11 isolates, four of them obtained by fluorescent-activated cell sorting (FACS). We also analyzed Symbiodinium diversity directly from Mussismilia tissue samples (N = 16) and characterized taxonomically the cultures and tissue samples by sequencing the dominant ITS2 region. Symbiodinium strains A4, B19, and C3 were detected. Symbiodinium C3 was predominant in the larger SAO reef system (Abrolhos), while Symbiodinium B19 was found only in deep samples from the oceanic Trindade Island. Symbiodinium strains A4 and C3 isolates were recovered from the same Mussismilia braziliensis coral colony. In face of increasing threats, these results indicate that Symbiodinium community dynamics shall have an important contribution for the resilience of Mussismilia spp. corals.

The mannose receptor is expressed by olfactory ensheathing cells in the rat olfactory bulb.

Complex carbohydrate structures are essential molecules of infectious bacteria, parasites, and host cells and are involved in cell signaling associated with immune responses, glycoprotein homeostasis, and cell migration. The uptake of mannose-tailed glycans is usually carried out by professional phagocytes to trigger MHC class I- and MHC class II-restricted antigen presentation or, alternatively, to end inflammation. We have detected the mannose receptor (MR) in cultured olfactory ensheathing cells (OECs), so we investigated by flow cytometry whether recently dissociated cells of the olfactory bulb (OB) nerve fiber layer (ONL) could bind a mannosylated ligand (fluorescein conjugate of mannosyl bovine serum albumin; Man/BSA-FITC) in a specific manner. In addition, we estimated the relative proportion of ONL OECs, microglia, and astrocytes, tagged by 2'3'-cyclic nucleotide 3'-phosphodiesterase (CNPase), by the B4 isolectin of Griffonia simplicifonia (IB4), and by glial fibrillary acidic protein (GFAP), respectively, that were Man/BSA-FITC(+) . We also determined by histochemistry and/or immunohistochemistry whether Man/BSA-FITC or an anti-MR antibody (anti-C-terminal MR peptide; anti-cMR) labeled OECs and/or parenchymal microglia. In addition, we confirmed by Western blot with the K1K2 (against the entire MR molecule) antibody that a band of about 180 kDA is expressed in the OB. Our findings are compatible with a prospective sentinel role of OECs against pathogens of the upper airways and/or damage-associated glycidic patterns as well as with homeostasis of OB mannosylated glycoproteins.

Food allergy/hypersensitivity: antigenicity or timing?

Mechanisms involved in the induction of oral tolerance (OT) or systemic immunization through the oral rout are still poorly understood. In our previous studies, we have shown that when normal mice eat peanuts they become tolerant, with no gut alterations. Conversely, if immunized with peanut proteins prior to a challenge diet (CD) containing peanuts they develop chronic inflammation of the gut. Our aim is to evaluate the consequences of the introduction of a novel protein in the diet of animals presenting antigen-specific gut inflammation. Adult, female C57BL/6J mice were divided in control (C) and experimental (E) groups. C1-C3 received peanut protein immunization, animals of the control groups C4 were sham immunized, and control group C5 received ovalbumin (OVA) immunization. The experimental group was immunized with peanut protein extract. Before initial exposure to a 30-day peanut containing CD, the experimental group was divided into 5 groups (E1-E5). OVA feeding began 7 days prior CD (E1) on day 0 (E2), 7 (E3), 14 (E4) and 21 (E5) during CD. Our results show that oral exposure to a novel protein (OVA) in the absence of gut inflammation (E1) leads to low levels of systemic antibody (Ab) titers, comparable to tolerant animals. Conversely, as off initial induction of inflammation, groups submitted to OVA (OT) protocol develop increasingly higher systemic Ab titers similar to animals of the immune control group. In conclusion, our protocol indicates that timing is more important than the antigenicity when a novel protein is offered, in the diet.