Tissues Of Helix Aspersa Research Articles

A comparative study of antioxidant enzyme activities in tissues of Helix aspersa (O. F. Müll.) and Pomacea bridgesi (Reeve)

Antioxidant enzymes: catalase (CAT) [EC 1.11.1.6], peroxidase [EC 1.11.1.7], glutathione reductase (GSSGR) [EC 1.6.4.2] and glucose-6-phosphate dehydrogenase (G6PDH) [EC 1.1.1.49] were investigated in terrestrial Helix aspersa (O.F. Mull.) and aquatic Pomacea bridgesi (Reeve). The activity was determined in the heamolymph and homogenates of hepatopancreas and foot muscle. No CAT and peroxidase activity was detected in the hepatopancreas and foot muscle of P. bridgesi, and its haemolymph displayed a very low CAT activity (0.005 U/mg of protein). In H. aspersa the highest activities (U/g) observed for CAT and GSSGR in the hepatopancreas were 0.40, and 1.05, respectively; for peroxidase and G6PDH in the foot muscle the respective values were 1.22 and 0.22. The activities of antioxidant enzymes determined in both snail species are much lower than the corresponding values for mammalian tissues.

Localisation of aminopeptidase activities in the central and peripheral nervous system of Helix aspersa by fluorescence histochemistry

1. Tissues of Helix aspersa have been examined histologically for the presence of aminopeptidase activity. 2. A variation of the novel fluorescent histochemical method of Back and Gorenstein (1989) was employed using Phe-, Leu- and Arg-4-methoxynaphthylamide substrates. 3. When using Phe- and Leu- derivatives, specific aminopeptidase activity was localised to neuronal axons in both circumoesophageal ganglia and the foot muscle of Helix aspersa. 4. The Arg compound failed to produce staining.

Aminopeptidase activities present in tissues of Helix aspersa

1. 1. Tissues of Helix aspersa have been examined for the presence of aminopeptidase activities. 2. 2. Enzyme activities were detected using synthetic peptide substrates containing the fluorescent leaving group 7-amino-4-methyl coumarin. The methods used included continuous fluorimetric assay and activity staining of enzymes in non-denaturing polyacrylamide gels. 3. 3. Several types of peptidase activity were detected, including three distinct aminopeptidases which differ in molecular size and substrate preference.

Some properties of high and low molecular weight aminopeptidase activities in tissues of helix aspersa

Some properties of high and low molecular weight aminopeptidase activities in tissues of helix aspersa

High-performance liquid chromatographic analysis of monoamines and some of their gamma-glutamyl conjugates produced by the brain and other tissues of Helix aspersa (Gastropoda).

1. Earlier reports from this and other laboratories have indicated that wide variations exist in estimates of the concentrations of norepinephrine in the brain and heart of the snail Helix aspersa. This is a report on investigations of norepinephrine concentrations in Helix aspersa tissues using high-performance liquid chromatography with electrochemical detection. In addition, the effects of treatment with some amino acid precursors or enzyme inhibitors on the concentrations of norepinephrine, dopamine, 5-hydroxytryptamine, and some of their metabolites were investigated. 2. The levels of norepinephrine in the brain were low (46 ng/g) in comparison to dopamine (2.1) micrograms/g) and 5-hydroxytryptamine (2.6 micrograms/g). Epinephrine was not observed in either snail heart of snail nervous tissue. 3. Administration of L-3,4-dihydroxyphenylalanine resulted in elevated snail brain dopamine, while 3,4-dihydroxyphenylserine treatment increased norepinephrine. Treatment with blockers of tyrosine hydroxylase and aromatic-L-amino acid decarboxylase reduced dopamine concentrations without affecting 5-hydroxytryptamine. 4. The dopamine metabolite 3,4-dihydroxyphenylacetic acid was observed only after administration of L-3,4-dihydroxyphenylalanine or dopamine and then only in very small amounts. At no time was the dopamine metabolite homovanillic acid or the 5-hydroxytryptamine metabolite 5-hydroxyindoleacetic acid observed in brain, heart, or whole-body extracts of the snail. 5. Incubation of nervous tissue with either dopamine or 5-hydroxytryptamine resulted in the production of electrochemically active metabolites which were identified by oxidation characteristics and cochromatography with synthesized standards as the gamma-glutamyl conjugates of the amines. Treatment of snails with 5-hydroxytryptamine or dopamine also resulted in the production of gamma-glutamyl conjugates. 6. The present experiments show that great care must be exercised when measuring monoamines and their metabolites in gastropod tissues by high-performance liquid chromatography with electrochemical detection.

Biochemical and pharmacological analyses of endogenous cardioactive peptides in the snail,Helix aspersa

1. Isoelectric focusing and ion-exchange chromatography are used to analyse the biochemical properties of cardioactive peptides derived from tissues ofHelix aspersa. 2. The small cardioactive peptide (SCP) appears to be a single peptide species with a molecular weight of ca. 1,000 and an isoelectric point between 10 and 13 (Fig. 1). 3. The large cardioactive peptides (LCP) are made up of two peptides with an identical apparent molecular weight of ca. 7,000. One has a neutral isoelectric point (LCPN), while the other is basic (LCPB) (Figs. 2 and 3). 4. Long-term perfusion of the isolated snail heart with SCP causes an increase in the amplitude and rate of the heart beat. This effect is indistinguishable from that of 5-hydroxytryptamine (5-HT) (Figs. 4 and 5). 5. The amplitude increase caused by SCP or 5-HT occurs more rapidly than the increase in rate (Fig. 4). 6. Perfusion of the heart with LCP causes an increase in beat amplitude and diastolic tone with no significant change in rate (Figs. 4 and 5). 7. The actions of LCPN and LCPB on the heart are essentially identical (Fig. 6). 8. The threshold for the action of perfused LCP is extremely low, less than the LCP from 0.001 auricle/ml (Fig. 7).

Choline esterase activity in the tissues of the snail Helix Aspersa

1. 1. The titrimetric method of Glick (1937) was used to measure cholinesterase activity in various tissues of Helix aspersa. 2. 2. Such activity was found in a variety of tissues and was particularly high in the heart. 3. 3. The activity showed some of the properties of a true cholinesterase.