Distribution of Molluscs

Purchon, R. D.

doi:10.1016/b978-0-08-021028-5.50016-4

Cited by 4 publications

(5 citation statements)

References 48 publications

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“…Mussels are capable of selective feeding on particles of different sizes and on different particles of similar size (Newell et al 1989). However, particle sorting in the digestive tract based on particle size (Purchon 1977) was not apparent in our study. The size of the algal cells in our study ranged from 2 to 40 pm, and we found little evidence to suggest that AE was directly related to the particle size of each algal species.…”

Section: Discussioncontrasting

confidence: 41%

“…Gut passage time-Several studies have shown food selectivity in the stomach and differential egestion of unassimilable particles after ingestion (Purchon 1977;Bricelj et al 1984;Shumway et al 1985). Shumway et al (1985), for example, demonstrated that a cryptomond flagellate was preferentially absorbed in the bivalve gut compared with a dinoflagellate and a diatom of similar size, Consequently, selective mechanisms in the stomach may affect organic enrichment in the particles entering the digestive tubules (Bayne 1993).…”

Section: Discussionmentioning

confidence: 99%

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Assimilation of trace elements and carbon by the mussel Mytilus edulis: Effects of food composition

Wang¹,

Fisher²

1996

Limnology & Oceanography

234

190

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Assimilation efficiency (AE) is an important physiological parameter in determining trace element influx from food sources into aquatic animals. We used radiotracer techniques to examine the influence of diet [seven species of algae (two diatoms, two chlorophytes, a prasinophyte, and two dinoflagellates) and glass beads] on the assimilation of seven trace elements (Ag, Am, Cd, Co, Cr, Se, Zn) and C in the mussel Mytilus edulis. Trace element assimilation was related to C assimilation and cytoplasmic distribution in the algae and to gut passage time in the mussels. Mussels displayed different C AEs for the different algal diets; the chlorophytes, which had highly refractory cell walls, were the least digestible food. Assimilation of Cd, Se, and Zn was directly correlated with C assimilation; for Am, Ag, and Cr, no relationship with C assimilation was apparent. For each species except the chlorophytes, AEs of all elements significantly correlated with their cytoplasmic distribution within each algal cell. Among all species, AEs of Am, Co, and Se also increased with elemental penetration into the cytoplasm; however, this relationship was not statistically significant for Ag, Cd, or Zn. With the exception of Cr, AEs of elements increased with gut passage time, implying more efficient digestion-absorption when the element was retained longer in the digestive tract. In waters containing large mussel populations, unassimilated particle-reactive elements should be removed from suspension and enriched in biodeposits in sediments, whereas assimilated metals should be enriched in mussel tissues.For bivalve molluscs, both dissolved and particulate sources can contribute to metal accumulation in tissues. Uptake of metals from the dissolved phase occurs primarily across the gills, after which metals are transported into various organs. Accumulation of metals from particulate sources occurs by ingesting and assimilating metals from particulate sources. Metal influx from particles is a direct function of the assimilation efficiency (AE) of metals, the metal concentration in the ingested particles, and the ingestion activity of the animal (Thomann 198 1;Luoma et al. 1992). Assimilation represents a first-order physiological process that can be compared among different metals, food types, and environmental conditions, and AE can be used to measure metal bioavailability from specific foods.l Corresponding author.

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Section: Discussioncontrasting

confidence: 41%

Section: Discussionmentioning

confidence: 99%

Assimilation of trace elements and carbon by the mussel Mytilus edulis: Effects of food composition

Wang¹,

Fisher²

1996

Limnology & Oceanography

234

190

View full text Add to dashboard Cite

show abstract

“…Most aquatic gastropods spend adult life in the benthic realm, from intertidal rocky shores to abyssal plains and hydrothermal vents. The evolutionary success of gastropods can be largely attributed to the structural and functional plasticity of the feeding apparatus (Purchon 1977;Kohn 1983).…”

Section: Introductionmentioning

confidence: 99%

Assessing the ecological vulnerability of Western Atlantic marine benthic gastropods

Carranza

Arim

2023

Mar Fish Sci

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Assessing the extinction risk in marine invertebrates poses serious challenges to conservation biology, due to the magnitude of marine biodiversity, the inaccessibility of most of the marine realm, and the lack of appropriate data on population dynamics and ecology for most species. However, simple life history traits have a huge potential for preliminary screening criteria for assessing large numbers of species whose status is harsh or impossible to evaluate. Body size and trophic position could be strong predictors of extinction risk providing a general framework for the assessment of species vulnerability. We analyzed the Body Size-Trophic Position (BS-TP) relationship along 1,067 genera representing 4,256 nominal species of western Atlantic benthic gastropods. We found that a carnivore diet characterizes 67% of the genera and that, supporting theoretical predictions, the probability of being carnivores as a function of size showed a unimodal trend. For species with adult body sizes larger than 5 cm, a negative association between trophic position and body size was detected. This result points to an energetic restriction for the viability of large species, implying that organisms placed near the BS-TP boundary are extremely vulnerable to environmental changes. With this result, 109 genera from 42 families of carnivore gastropods and 33 genera from 19 families of herbivore gastropods that may be more vulnerable from the analyzed perspective were identified and ranked. Supporting these results, while the most vulnerable genera are not represented in global IUCN assessments, all our ‘top 10’ vulnerable families are being considered in National or Regional Red Lists. Prior to conducting regional or global conservation assessments for invertebrate taxa, screening methods should be strongly considered.

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“…In aquatic ecosystems, cellulose is produced in large quantities by algal plankton, which is an important energy source for filter feeding organisms such as mussels (Newell et al, 1989). Not surprisingly, cellulase activity has been demonstrated in the digestive tract of several bivalves (Kaur, 1997;Onishi et al, 1985;Purchon, 1977). The highest activity was found in so called crystalline styles, which most bivalves and some gastropods (snails and slugs) use for digestion.…”

Section: Introductionmentioning

confidence: 99%

“…It aids in digestion by being rotated and pushed against the gastric shield, thus dragging the food from the gills into the stomach and grinding the food like a pestle and mortar. The style dissolves gradually and releases various enzymes that initiate extracellular digestion in the stomach (Purchon, 1977).…”

Section: Introductionmentioning

confidence: 99%

Structure and function studies of GH45 glycoside hydrolases

Okmane¹

2023

Acta Universitatis Agriculturae Sueciae

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The enzymatic hydrolysis of lignocellulosic material in nature is carried out by a plethora of cellulases. Glycoside hydrolase family 45 (GH45) enzymes are small cellulases most commonly found in fungi that catalyse the hydrolysis of β(1→4) linked glucans. Additionally, GH45 enzymes display a structural resemblance to non-hydrolytic protein groups such as expansins and loosenins. In this thesis, the distinctness of GH45 enzymes from different subfamilies was explored. The enzymatic activity of GH45 enzymes from Humicola insolens (HiCel45A), Mytilus edulis (MeCel45A), Trichoderma reesei (TrCel45A), Phanerochaete chrysosporium (PcCel45A), Gloeophyllum trabeum (GtCel45A) was demonstrated. Among the tested substrates were barley betaglucan, konjac glucomannan, carboxymethyl cellulose, and cellohexaose. Initial hydrolysis rates and hydrolysis yields were determined by reducing sugar assays, product formation was analysed using NMR spectroscopy and HPLC. The subfamily B and C enzymes exhibited mannanase activity, and the subfamily B enzyme MeCel45A appeared cold adapted in comparison to TrCel45A. GH45 enzymes are known to act using an inverting action mechanism. This action mechanism had not been experimentally demonstrated in subfamilies B and C, however. Here experimental evidence is provided for the inverting nature of GH45 enzymes from all subfamilies. Comparisons of GH45 enzyme structures were carried out and the first crystal structure of a GH45 subfamily C enzyme from the brown-rot fungus G. trabeum was reported at 1.3 Å resolution. Furthermore, structure and function investigations were done on an isotopically labelled Cel45A from the white-rot fungus P. chrysosporium using NMR spectroscopy. PcCel45A was expressed in Pichia pastoris with 13C and 15N labelling. A nearly complete assignment of 1 H, 13C and 15N backbone resonances was obtained and the interaction of 15Nlabelled PcCel45A with cellobiose was studied.

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Distribution of Molluscs

Cited by 4 publications

References 48 publications

Assimilation of trace elements and carbon by the mussel Mytilus edulis: Effects of food composition

Assimilation of trace elements and carbon by the mussel Mytilus edulis: Effects of food composition

Assessing the ecological vulnerability of Western Atlantic marine benthic gastropods

Structure and function studies of GH45 glycoside hydrolases

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