Long chain polyunsaturated fatty acid synthesis in a marine vertebrate: Ontogenetic and nutritional regulation of a fatty acyl desaturase with Delta4 activity

Solea senegalensis is an unusual marine teleost as it has very low dietary requirement for long-chain polyunsaturated fatty acids (LC-PUFA) during early development. Aquaculture is rapidly becoming the main source of health-beneficial fish products for human consumption. This, associated with limited supply of LC-PUFA-rich ingredients for fish feeds, render S. senegalensis a highly interesting species in which to study the LC-PUFA biosynthesis pathway. We have cloned and functionally characterized fatty acyl desaturase and elongase cDNAs corresponding to D4fad (with some D5 activity for the n-3 series) and elovl5 with the potential to catalyze docosahexaenoic acid (DHA) biosynthesis from eicosapentaenoic acid (EPA). Changes in expression of both transcripts were determined during embryonic and early larval development, and transcriptional regulation in response to higher or lower dietary n-3 LC-PUFA was assessed during larval and post-larval stages. There was a marked pattern of regulation during early ontogenesis, with both transcripts showing peak expression coinciding with the start of exogenous feeding. Although elovl5 transcripts were present in fertilized eggs, D4fad only appeared at hatching. However, eggs have high proportions of DHA (~ 20%) and high DHA/EPA ratio (~ 11) to meet the high demands for early embryonic development. The fatty acid profile of larvae after the start of exogenous feeding closely reflected dietary composition. Nonetheless, D4fad was significantly up-regulated in response to LC-PUFA-poor diets, which may suggest biological relevance of this pathway in reducing LC-PUFA dietary requirements in this species, compared to other marine teleosts. These results indicate that sole is capable of synthesizing DHA from EPA through a Sprecher-independent pathway

Evaluation of a model for induction of periodontal disease in dogs

There are several methods for inducing periodontal disease in animal models, being the bone defect one of the most reported. This study aimed to evaluate this model, through clinical, radiographic, tomographic and histological analyzes, thus providing standardized data for future regenerative works. Twelve dogs were subjected to the induction protocol. In a first surgical procedure, a mucoperiosteal flap was made on the buccal aspect of the right third and fourth premolars and a defect was produced exposing the furcation and mesial and distal roots, with dimensions: 5mm coronoapical, 5mm mesiodistal, and 3mm buccolingual. Periodontal ligament and cementum were curetted and the defect was filled with molding polyester, which was removed after 21 days on new surgical procedure. Clinical and radiographic examinations were performed after the two surgeries and before the collection of parts for dental tomography and histological analysis. All animals showed grade II furcation exposure in both teeth. Clinical attachment level increased after induction. Defect size did not change for coronoapical and buccolingual measurements, while mesiodistal size was significantly higher than at the time of defect production. Radiographic analysis showed decreased radiopacity and discontinuity of lamina dura in every tooth in the furcation area. The horizontal progression of the disease was evident in micro-computed tomography and defect content in the histological analysis. Therefore, it is concluded that this method promotes the induction of periodontal disease in dogs in a standardized way, thus being a good model for future work