Direct measurements of sugar uptake from seawater into molluscan larvae

Abstract

A method for the direct measurement of picomole amounts of mono-, di-, and trisaccharides in seawater was developed by combining high-performance liquid chromatography (HPLC) with amperometric detection. This new method is described and then applied to the study of sugar uptake from seawater into veliger larvae of a bivalve (Crassostrea gigas) and a gastropod (Haliotis rufescens). Bivalve veligers take up glucose, maltose, cellobiose, and cellotriose but not L-rhamnose, isomaltose, maltotriose, or isomaltotriose. Similarly, gastropod veligers take up glucose and maltose, but not L-rhamnose or maltotriose. Glucose and maltose are transported into the bivalve veligers by separate pathways and the influx of "C-labeled glucose is a good measure of the net flux (measured by HPLC) The uptake of complex sugars, in addition to monosacchai-ides, permits inolluscan larvae to utilize a greater part of the dissolved organic material in the sea as a source of nutrition

Amperometric detection of carbohydrates based on the glassy carbon electrode modified with gold nano-flake layer

“…7B) which may be a result of the post-column alkaline addition [16] or the rough surface of nano-Au layer [17]. Although the nano-Au/GC/ECCs using the non-oxidative PAD possessed the detection limits of carbohydrates which are about 50-fold higher than previously reported results [18], the reproducibility of peak areas was very good (RSD % 2%, n = 6) which could be a consequence of the complete elimination of gold oxidation. Therefore, this method is suitable for food and biological samples which contain high levels of carbohydrates and interfering substances.…”

Effects of nutrition on larval growth and survival in bivalves

“…The study did not determine which components of the fraction contributed to the improved growth. Molluscan larvae have been shown to directly uptake sugars (Welborn & Manahan (1990) for C. gigas ) and amino acids (Manahan (1983) for C. gigas and M. edulis ) from seawater. The uptake of fatty acids by bivalve larvae is not well researched, but there are examples from other invertebrates, such as the non‐feeding larvae of the sponge Tedania ignis (Porifera, Demospongiae), which can transport palmitic acid across the epidermis (Jaeckle 1995).…”

Effect of amino acids on larval metamorphosis of the polychaete Hydroides elegans

“…The interaction among settling larvae, amino acids, and marine bacteria can be very complex issue since there have been reports that larvae of marine invertebrates may uptake amino acids and other dissolved organic matter as the nutrient for larval development (Welborn & Manahan 1990, Shilling & Manahan 1994. However, previous studies on the larval uptake of dissolved matter were assessed by monitoring the decline in amino acids (or dissolved organic matter) in the testing vessels over time, and did not investigate biofilm development in their experimental vessels.…”