Digestive Gland Extracts Research Articles

Speciation of bound and free metals evaluated for lobster digestive gland extracts

A simple method is described for the speciation of metalions in biological extracts with a short desalting gel-filtration column. The system was optimized for the eluent and gel type to provide accurate free metal ion levels and minimum processing times. The four separation media studied were Sephadex G25, Bio-Gel P-6DG, controlled pore glass CPG40, and Fractogel HW40F. The best medium was the Fractogel HW40F because it was not compressible and allowed a pump to be used to obtain uniform flow rates. The eluent was 0.10 M ammonium acetate/0.01 M citric acid adjusted to pH 7.0. This eluent minimized ion/gel interactions and gave a lower salt content relative to other possible eluents. The separation time was 10 min per sample per metal ion of interest. The detection limits relative to the mass of wet tissue for the column/flame spectrometer system were 0.80 μg g −1, 0.80 μg g −1, and 1.6 μg g −1 for zinc, cadmium and copper, respectively. The method is evaluated for a lobster digestive gland extract; the methodology should be applicable to other systems containing nonlabile metal species.

Analysis of enzymes in theBulinus tropicus/truncatuscomplex (Mollusca: Planorbidae)

Summary Five enzymes in the crude digestive gland extracts of individual snails of the B. tropicus/truncatus complex have been analysed by isoelectric focusing in polyacrylamide gels. The enzymes studied were: malate dehydrogenase (MDH); phosphoglucomutase (PGM); glucosephosphate isomerase (GPI); acid phosphatase (AcP) and hydroxybutyrate dehydrogenase (HBDH). Snails from 103 population samples (52 diploid, 51 tetraploid) from diverse geographical origins have been studied. Diploid and tetraploid snails were clearly differentiated and regional distributions of certain enzyme types are reported. The taxonomic implications of the findings are discussed.

FEEDING AND PHARMACOLOGICAL PROPERTIES OFANISODORIS NOBILISINDIVIDUALS (MOLLUSCA; NUDIBRANCHIA) SELECTING DIFFERENT NOXIOUS SPONGES PLUS DETRITUS

Individual differences in Anisodoris nobilis food selection were sought in the natural environment, to determine why their digestive glands differed pharmacologically. Of 73 stationary A. nobilis specimens turned over in the initial survey, 84% of those on sponges and 65% of those on detritus had their mouths everted; no others were feeding. Microacoustic observations showed that an individual stops on a sponge, everts its proboscis for a long period, then rasps the sponge. Field studies of individual diets were made without disturbing the animals, by tabulating the foods on which each nudibranch was found to be stationary.Twelve individual nudibranchs observed subtidally about three times daily for 8 days differed significantly in the sponge species they selected. Each individual was found stopped on detritus during roughly 50% of the observations, remaining there for 1 day at a time. Each nudibranch stopped for <2 days on a sponge, sometimes returning to that spot during subsequent days. Among individuals transplanted to different feeding sites, each everted its mouth only when on the sponge species it had been eating at the previous site. Two months of subsequent, scattered observations showed occasional longer-term feeding differences.Noxious histamine (present in each sponge) and doridosine (found only in the nudibranch) accounted for different pharmacological properties in bioassays of Anisodoris digestive gland extracts. Histamine disappeared when the nudibranchs ate detritus, which suggests that this mixed diet purges sponge compounds from the nudibranch. Extracts from edible sponges administered to nudibranchs caused fleeing, while extracts of avoided sponges caused violent contractions, increased mucus production, and even death.

Inducement of miracidia-immobilizing substance in the hemolymph of Biomphalaria glabrata

Lie K. J., Jeong K. H. and Heyneman D. 1980. Inducement of miracidia-immobilizing substance in the hemolymph of Biomphalaria glabrata. Intemational Journal for Parasitology 10: 183–188. More than 85% of echinostome-infected albino B. glabrata laboratory strain snails develop miracidia-immobilizing substance(s) (MIS) in the hemolymph, while less than 5% of control uninfected snails show this ability. Snails infected with Echinostoma lindoense show a strong miracidial immobilizing test (MIT) when homologous miracidia are exposed to the hemolymph and a moderate response when E. liei and Paryphostomum segregatum miracidia are used. Infection with E. paraensei results in a high level of hemolymph MIS with E. lindoense miracidia, a moderate one with P. segregatum miracidia, and a weak one when hemolymph is tested against E. liei as well as the homologous E. paraensei miracidia. Infection with E. liei induces a strong MIT with E. lindoense miracidia whereas only a moderate one was observed when using homologous or P. segregatum miracidia. Infection with P. segregatum gives a moderate MIT reaction to miracidia of the homologous species, as well as to E. lindoense and E. liei, and only a weak response to E. paraensei miracidia. Infection with S. mansoni fails to induce hemolymph that shows MIS to any of the parasites tested. Production of hemolymph MIS is temporary. It begins one day postexposure, reaches its maximum 10–14 days postexposure, and declines to the preinfection level several weeks later. Infection of snails with irradiated parasites also results in a temporary production of hemolymph MIS. Uninfected snails show a tissue-extract MIS, which is especially strong when digestive gland extracts are used. However, these snails give little or no evidence of a hemolymph MIS.

Identification of phaeopigments in the digestive gland of Mytilus edulis L. by microspectrofluorimetry

Epi-illuminated fluorescence microscopy was used to observe chlorophyll degradation products localized in lipid spherules within the digestive gland of Mytilus edulis L. These fluorescing materials, known collectively as phaeopigments, then were spectrally analysed in situ with a microspectrofluorimeter. The results were compared with acetone extracts of the digestive gland and chlorophyll a standard solutions. Emission wavelength peaks were 671.2 nm for chlorophyll a in 85% acetone, and 672.8 nm for the acidified chlorophyll a solution, 66.3 nm for digestive gland extracts in 85% acetone, and 677.1 nm for phaeopigment in tissue sections. Acid factors of 1.0 for digestive gland extracts and tissue sections confirmed the red fluorescing material to be phaeopigment. Quantities up to 167 ng for an 11-μm diameter lipid spherule were encountered. Results were compared with calculated concentrations of phaeopigment determined spectrophotometrically.

Analysis of enzymes in theBulinus africanusgroup (Mollusca: Planorbidae) by isoelectric focusing

Summary Four enzyme systems have been analysed in digestive gland extracts of snails of the Bulinus africanus group. Forty population samples, representing eight of the ten nominal species recognized in the group, have been examined. Three distinct enzyme types were recognized in each of three of the systems and ten types in the fourth. Few of the individual enzyme types show marked restriction in either their taxonomic or geographic distributions. However, certain combinations of types appear to be associated with some nominal taxa and others with regional distributions.

Enzyme analyses of Bulinus africanus group snails (Mollusca: Planorbidae) from Tanzania

38 population samples of snails of the Bulinus africanus group, collected from three separate areas of Tanzania, have been examined. Enzymes in crude digestive gland extracts of individual snails have been analysed by isoelectric focusing in polyacrylamide gels. The enzymes studied were: malate dehydrogenase (MDH); phosphoglucomutase (PGM); glucosephosphate isomerase (GPI); acid phosphatase (AcP) and hydroxybutyrate dehydrogenase (HBDH). Samples of B. nasutus were clearly differentiated from other species and enzyme differences were apparent between samples from the lake and coastal areas. Similarly, although clear distinctions could not always be made, samples of B. africanus, B. globosus and B. ugandae were characterized by their enzyme types. Individual variation was detected within populations and the significance of enzyme polymorphisms in relation to identification has been considered. No correlation was found between snail enzyme type and susceptibility to Schistosoma haematobium or S. bovis.

Schistosoma mansoni: Lysozyme activity in Biomphalaria glabrata during infection with two strains

Levels of lysozyme activity were determined in the hemolymph, digestive gland, and headfoot extracts of M-line stock of snails, Biomphalaria glabrata, during infection with the PR-1 and Lc-1 strains of the trematode, Schistosoma mansoni. At 3 hr postexposure there was a 10-fold increase in the levels of enzyme activity in the hemolymph of snails infected with the Lc-1 strain to which the snail is resistant. This increase was considerably higher when compared to the threefold increase in the PR-1-infected snails. The infection also induced a gradual depletion of lysozyme activity in the headfoot muscles of the two groups of infected snails. There were no changes in the levels of enzyme activity in the digestive gland extracts of the control and the two groups of infected snails. Similar changes in the levels of enzyme activity in the hemolymph and headfoot extracts of infected snails suggest a nonspecific response to a parasite infection and do not indicate that lysozyme is primarily responsible for the destruction of schistosome parasite in a resistant snail host.

Biomphalaria glabrata: Lysozyme activities in the hemolymph, digestive gland, and headfoot of the intermediate host of Schistosoma mansoni

Lysozyme (mucopeptide N-acetylmuramylhydrolase EC 3.2.1.17) activity has been found in the hemolymph, digestive gland, and headfoot extracts of Biomphalaria glabrata, the intermediate host of Schistosoma mansoni. Partial purification of the bacteriolytic enzyme was attained by gel chromatography on Sephacryl S-200 and active lytic fractions were concentrated by Amicon filtration. The properties of the lytic enzymes from the three tissue extracts were identical. Enzyme activity was determined by the rate of lysis of cell wall suspension of Micrococcus lysodeikticus. Lysis of the cell walls was accompanied by a release of reducing sugar groups and N-acetylhexosamines. The enzyme was stable to heating at 100 C for 2 min and had an optimum activity at pH 4.5 to 5.0 in 0.066 M glycylglycine buffer. Low concentrations (5 m M) of NaCl, KCl, and LiCl increased the activity of the enzyme, whereas high concentrations (25 m M) of the same ions caused about 50% inhibition of the enzyme activity. MgCl 2 and CaCl 2 also inhibited the enzyme activity. Addition of 1 m M EDTA or EGTA resulted in about a twofold increase in enzyme activity. Double reciprocal plots of enzyme velocities and substrate concentrations yielded an apparent Michaelis-Menten constant ( K m ) of 0.05 ± 0.01 mg/ml of M. lysodeikticus.

Variations des zymogrammes du tube digestif et du muscle chez Cyclonassa neritea en fonction de la température d'acclimatation

Soluble proteins, esterases 2C, acid phosphatases of the digestive gland and foot muscle of Cyclonassa neritea, were compared using polyacrylamide gradient gels. α-Glucosidases, alkaline phosphatases, l-leucine aminopeptidase and peptidase were studied from digestive gland extracts. Molecular weights of isoenzymes were evaluated with 5000 d accuracy. Variation in activity of the most important isoenzymes of each enzyme under the influence of acclimation temperature was measured. In both muscle and digestive gland, the concentration of soluble proteins is stable. Through the whole acclimation temperature range, esterase activity per mg protein decreased with increased temperature. l-Leucine aminopeptidase activity decreases steadily from 10 to 25°, even though the two alkaline phosphatase isoenzyme activities increase. The other enzymes have their maximum activities at 20°.

Multiple sources of esterase enzymes in the crop juice ofCepaea (Mollusca: Helicidae)

Previous workers have (a) compared pulmonate crop juice and digestive gland extracts and found a close similarity in the enzymic complements from these two sources, and (b) located specific enzymes within the various cell types of the digestive gland. The digestive gland seems to be the major source of extracellular enzymes but what is not clear is which of the enzymes associated with particular intracellular structures are actively secreted into the crop juice. The present study has used polyacrylamide disc gel electrophoresis to investigate the digestive gland and crop juice esterases ofCepaea nemoralis andC. hortensis. It appears that only some of the digestive gland esterases are specifically secreted. The variation shown in crop juice esterases suggests three independent sources in the digestive gland. Less detailed studies ofHelix aspersa andArianta arbustorum also indicate multiple sources of extracellular esterases.

Letter: A novel diterpene from Dollabella californica.

The sea hare Dollabella californica Sterns, a large softbodied opistobranch mollusk, was collected at Isla Partida, Gulf of California. The digestive gland of Dollabella, contained a number of terpenoid compounds which are probably of dietary origin. The major components of the digestive gland extracts are a series of diterpenes which appear to be closely related. The structural determination has been obtained by single-crystal x-ray diffraction analysis for a diterpene 1 having a novel 5,11-bicyclic carbon skeleton. (DDA)

Increased alkaline phosphatase in the tissues and hemolymph of the snail Biomphalaria glabrata infected with Schistosoma mansoni

1. 1. Using polyacrylic gel electrophoresis, we demonstrated the presence of alkaline phosphatase in some hemolymph samples and in all digestive gland extracts prepared from two strains of Biomphalaria glabrata. 2. 2. All hemolymph samples from Schistosoma mansoni-infected snails showed two slow-moving bands of enzyme; in one-third of the hemolymph samples from normal snails, however, alkaline phosphatase activity was undetectable by electrophoresis. 3. 3. Extracts of digestive gland from both normal and infected snails showed electrophoretic patterns similar to those obtained from hemolymph. 4. 4. Colorimetric techniques demonstrated increased alkaline phosphatase levels in both the hemolymph and digestive glands from infected snails.

Determination of some water-soluble vitamin levels in Planorbidae

Some water-soluble vitamin levels were determined in total snail and in digestive gland extracts of Biomphalaria glabrata. Vitamin B 12, folic acid, and pyridoxin levels were higher in digestive gland extract than in total snail extract. Conversely, the levels of choline, nicotinic acid, biotin and para-aminobenzoic acid were higher in total snail extract.