A comprehensive biochemical characterization of settlement stage leptocephalus larvae of bonefish (Albula vulpes).

Little is known about early development of the near-threatened bonefish (Albula vulpes), a member of superorder Elopomorpha. Members of Elopomorpha are partially defined by their synapomorphic leptocephalus larval stage, for which the nutritional requirements are not well understood. Characterizing the nutritional profile, including major nutrients (such as lipids) used for energetic processes, can help to gain a better understanding of the nutritional requirements for leptocephalus larvae. A total of 24 settlement stage A. vulpes leptocephalus larvae were collected at Long Caye Island, Belize. Samples were used to determine various biochemical characteristics including lipid class, fatty acid and glycosaminoglycan compositions. Each of these biochemical components plays a role in early developmental processes such as cellular membrane formation and is crucial for healthy development. Biochemical characteristics of settlement stage A. vulpes leptocephalus are presented in this study for the first time. The dominant lipid classes and fatty acids detected in these samples were consistent with prior studies using closely related species like the Japanese eel, indicating possible similarities in diets at this stage. In the future, similar analyses can be applied to other species that share the leptocephalus life stage to determine if nutritional requirements at this stage of development are unique to this species. The findings in this study will also help to facilitate the establishment of adequate aquaculture systems for captive bonefish, ultimately leading to improved management strategies for wild bonefish habitats.

Lipid Composition and Utilization in Early Stage Leptocephalus Larvae of Bonefish (Albula vulpes).

In order to encourage the survival of both captive and wild populations of bonefish (Albula vulpes), a deeper understanding of the species' early developmental characteristics is necessary. During ontogenesis, bonefish utilize lipids as a source of energy before the start of exogenous feeding. The goal of this study is to gain insight into the energetic needs of bonefish leptocephalus larvae in the post-hatch larval stage. Broodstock were collected in the wild and hormone induced. Spawning yielded eggs that were fertilized and were then incubated until hatching. Larval development was monitored throughout the duration of the trial until all larvae perished. Samples of larval tissue were taken to the lab for lipid analysis and composition was compared at different developmental stages. Larval lipid composition was significantly different across sample groups showing a change in lipid content related to development. After hatching, larvae gradually depleted wax esters-sterol ester (WE-SE) reserves over a period of 4 days, while simultaneously increasing hydrocarbon (HC). The role of WE-SE is seemingly tied to both buoyancy and energy reserves due to its high abundance immediately post-hatch and selective catabolism. As larvae weaned off of the nutrition provided by the yolk, exogenous feeding began to diversify lipid composition and overall lipid reserves were depleted. Future directions included the development of optimal larval feeds based on this analysis in order to gain more insight into the nutritional needs and requirements during the critical leptocephalus stages.

A flexible approach to studying post-transcriptional gene regulation in stably transfected mammalian cells.

The study of post-transcriptional regulation is constrained by the technical limitations associated with both transient and stable transfection of chimeric reporter plasmids examining the activity of 3'-UTR cis-acting elements. We report the adaptation of a commercially available system that enables consistent stable integration of chimeric reporter cDNA into a single genomic site in which transcription is induced by tetracycline. Using this system, we demonstrate the tight control afforded by this system and its suitability in mapping the regulatory function of defined cis-acting elements in the human TNF 3'-UTR, as well as the distinct effects of serum starvation on transiently transfected and stably integrated chimeric reporter genes.