An in vitro study of amino acid and sugar absorption in the gut of Echinus esculentus

Absorption ofL-alanine and other dissolved nutrients by the spines ofParacentrotus lividus(Echinoidea)

“…Thus at comparable temperatures, the K t values for uptake of three different amino acids, in three different phyla, are found to be of the same order of magnitude. In contrast, the K t values for uptake in invertebrate gut tissue appear to be much higher; the K t for L-alanine uptake in Arenicola gut was found to be 0-63 HIM (Bamford & Stewart, 1973), and for Echinus intestine, 1-04 mM (Bamford & James, 1972) indicating specialization of the absorption systems in these tissues for the transport of nutrients from a more concentrated solution.…”

Absorption ofL-alanine and other dissolved nutrients by the spines ofParacentrotus lividus(Echinoidea)

“…Thus at comparable temperatures, the K t values for uptake of three different amino acids, in three different phyla, are found to be of the same order of magnitude. In contrast, the K t values for uptake in invertebrate gut tissue appear to be much higher; the K t for L-alanine uptake in Arenicola gut was found to be 0-63 HIM (Bamford & Stewart, 1973), and for Echinus intestine, 1-04 mM (Bamford & James, 1972) indicating specialization of the absorption systems in these tissues for the transport of nutrients from a more concentrated solution.…”

Specificity of L-Alanine Transport in the Spine Epithelium of Paracentrotus Lividus (Echinoidea)

“…The presence of D-alanine was found to stimulate L-alanine uptake in Arenicola gut (Bamford & Stewart, 1973 a) and in Mytilus gill (Elliott, 1975). A preference for the L-isomer of alanine was established in Echinus gut (Bamford & James, 1972) and in the gills of Mya arenaria (Stewart & Bamford, 1975). In both instances, D-alanine did not inhibit L-alanine competitively, although the reverse occurred.…”

Effects of complexing agents on the distribution of Hg(II) species provided by food to starfishLeptasterias polaris

“…As proteins bear sulfydryl groups for which mercury and other trace metals have a high affinity (Rabenstein, 1978 ), they could serve as a moving platform for heavy metals transportation, and particularly for mercury. Furthermore, research on mechanisms of absorption of soluble organic nutrients suggested the presence of an active carrier-mediated system (Ferguson, 1964;Bamford and James, 1972) which can also be invoked in the transport of mercury species.…”

Absorption ofL-alanine and other dissolved nutrients by the spines ofParacentrotus lividus(Echinoidea)

“…Thus at comparable temperatures, the K t values for uptake of three different amino acids, in three different phyla, are found to be of the same order of magnitude. In contrast, the K t values for uptake in invertebrate gut tissue appear to be much higher; the K t for L-alanine uptake in Arenicola gut was found to be 0-63 HIM (Bamford & Stewart, 1973), and for Echinus intestine, 1-04 mM (Bamford & James, 1972) indicating specialization of the absorption systems in these tissues for the transport of nutrients from a more concentrated solution.…”

Specificity of L-Alanine Transport in the Spine Epithelium of Paracentrotus Lividus (Echinoidea)

“…The presence of D-alanine was found to stimulate L-alanine uptake in Arenicola gut (Bamford & Stewart, 1973 a) and in Mytilus gill (Elliott, 1975). A preference for the L-isomer of alanine was established in Echinus gut (Bamford & James, 1972) and in the gills of Mya arenaria (Stewart & Bamford, 1975). In both instances, D-alanine did not inhibit L-alanine competitively, although the reverse occurred.…”

Effects of complexing agents on the distribution of Hg(II) species provided by food to starfishLeptasterias polaris

“…As proteins bear sulfydryl groups for which mercury and other trace metals have a high affinity (Rabenstein, 1978 ), they could serve as a moving platform for heavy metals transportation, and particularly for mercury. Furthermore, research on mechanisms of absorption of soluble organic nutrients suggested the presence of an active carrier-mediated system (Ferguson, 1964;Bamford and James, 1972) which can also be invoked in the transport of mercury species.…”

Absorption ofL-alanine and other dissolved nutrients by the spines ofParacentrotus lividus(Echinoidea)

“…Thus at comparable temperatures, the K t values for uptake of three different amino acids, in three different phyla, are found to be of the same order of magnitude. In contrast, the K t values for uptake in invertebrate gut tissue appear to be much higher; the K t for L-alanine uptake in Arenicola gut was found to be 0-63 HIM (Bamford & Stewart, 1973), and for Echinus intestine, 1-04 mM (Bamford & James, 1972) indicating specialization of the absorption systems in these tissues for the transport of nutrients from a more concentrated solution.…”

Specificity of L-Alanine Transport in the Spine Epithelium of Paracentrotus Lividus (Echinoidea)

“…The presence of D-alanine was found to stimulate L-alanine uptake in Arenicola gut (Bamford & Stewart, 1973 a) and in Mytilus gill (Elliott, 1975). A preference for the L-isomer of alanine was established in Echinus gut (Bamford & James, 1972) and in the gills of Mya arenaria (Stewart & Bamford, 1975). In both instances, D-alanine did not inhibit L-alanine competitively, although the reverse occurred.…”

Effects of complexing agents on the distribution of Hg(II) species provided by food to starfishLeptasterias polaris

“…As proteins bear sulfydryl groups for which mercury and other trace metals have a high affinity (Rabenstein, 1978 ), they could serve as a moving platform for heavy metals transportation, and particularly for mercury. Furthermore, research on mechanisms of absorption of soluble organic nutrients suggested the presence of an active carrier-mediated system (Ferguson, 1964;Bamford and James, 1972) which can also be invoked in the transport of mercury species.…”