Structure and function of the digestive system in molluscs

Lobo-da-Cunha, Alexandre

doi:10.1007/s00441-019-03085-9

Cited by 44 publications

(21 citation statements)

References 142 publications

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“…Lysosomes with this aspect were not observed in the cells with short microvilli, which seem to contain lysosomal residual bodies. In ultrastructure and function, the absorptive cells of the esophageal pouches of chitons resemble the digestive cells of mollusk digestive gland (Lobo‐da‐Cunha, 1997, 2019). These cell types of the esophageal pouches and digestive gland both contain many lysosomes where substances collected by endocytosis are digested, store lipid and glycogen reserves and contain a considerable number of peroxisomes, some of them with a large diameter, especially in A .…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, the histochemical techniques applied in this study showed that the secretory vesicles of these cells have a glycoprotein content. Thus, the basophilic secretory cells of the esophageal pouches share ultrastructural features and histochemical properties with basophilic secretory cells of the digestive gland which are considered responsible for enzyme secretion for extracellular digestion in mollusks (Lobo‐da‐Cunha, 2019). Proteins were also detected in some vesicles of the other secretory cell type found in the esophageal pouches, but these are mucus‐secreting cells.…”

Section: Discussionmentioning

confidence: 99%

“…Esophageal pouches or distinct glands linked to the esophagus by ducts are also present in several gastropods (Lobo‐da‐Cunha, 2019). For instance, in the limpet Patella vulgata , the middle esophagus has numerous glandular pouches with epithelial cells that are responsible for nutrient absorption and amylase secretion for extracellular digestion (Bush, 1989).…”

Section: Discussionmentioning

confidence: 99%

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Functional morphology of the glandular esophageal pouches of chitons (Mollusca, Polyplacophora)

Lobo‐da‐Cunha¹,

Alves

Oliveira

et al. 2020

Journal of Morphology

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The esophageal pouches of Chaetopleura angulata and Acanthochitona fascicularis were investigated using light and transmission electron microscopy. These pouches linked to the posterior region of the esophagus are known as sugar glands as they contain a fluid rich in polysaccharide digesting enzymes. They are the second largest glands in the digestive system of chitons, just after the digestive gland. In both species, the pouches contain a dense array of finger‐shaped villi. The villi epithelium includes absorptive cells, basophilic secretory cells, mucus‐secreting cells, and basal cells. Some absorptive cells were bordered by a dense cover of long microvilli, whereas other absorptive cells had short and sparse microvilli. Absorptive cells contain several lysosomes, mitochondria, peroxisomes, a few small Golgi stacks, some lipid droplets, and large amounts of glycogen. The basophilic secretory cells are characterized by the presence of many electron‐dense vesicles, with a glycoprotein content, a large number of rough endoplasmic reticulum cisternae, and a highly developed Golgi apparatus. Mucus‐secreting cells are characterized by large vesicles containing acid polysaccharides and wide Golgi stacks. Basal cells that were found at the base of the epithelium in contact with the basal lamina exhibit histological and ultrastructural features of enteroendocrine cells. We suggest that these glandular pouches are involved in extracellular and intracellular digestion, and accumulate lipid and glycogen reserves.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Functional morphology of the glandular esophageal pouches of chitons (Mollusca, Polyplacophora)

Lobo‐da‐Cunha¹,

Alves

Oliveira

et al. 2020

Journal of Morphology

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“…During an attack, the toxic secretions produced by the posterior salivary glands are delivered to the prey through a wound created by quick bite rather than by injection through the two-piece beak (also called rostrum). Toxins with immobilising properties, with the aid of permeabilising enzymes plus cardioexcitatory and vasodilatory substances, are promptly disseminated through the prey's circulatory system, rapidly affecting mobility and motor coordination (Zhang, 2015;Lobo-da-Cunha, 2019). Likely, the copious amount of mucus comprising neutral glycoproteins, sialic acid, dipeptidase and hyaluronidase secreted by the anterior salivary glands, is the delivery vehicle of the bioactive compounds secreted by the posterior salivary glands (Budelmann et al, 1997;Ponte and Modica, 2017).…”

Section: Secretion Delivery and Mode-of-actionmentioning

confidence: 99%

Cephalotoxins: A Hotspot for Marine Bioprospecting?

Gonçalves

Costa

2021

Front. Mar. Sci.

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Molluscs provided one of the pioneering approved pharmaceuticals from the seas: the painkiller ziconotide, developed from an ω-conotoxin isolated from cone snails. As marine biotechnologists are turning towards the immense range of novel bioproducts from marine invertebrates, little attention has been given to cephalotoxins, a group of obscure proteinaceous toxins produced by the salivary glands of coleoids, i.e., octopuses, squids and cuttlefishes. These toxins, for which there is empirical evidence for acting as immobilisers at least against crustaceans, are proteinaceous substances among the many that comprise the venomous mixtures secreted by these animals. Despite the ecological and economical importance of cephalopods, little is known about cephalotoxins, beginning with the actual span of taxa that secrete them. Indeed, cephalopods are long suspected for producing specific toxins as part of their predation and defence mechanisms, making them a promising group of marine animals for the bioprospecting of novel compounds. Despite scant or absent toxicological or otherwise experimental evidence for their bioreactivity, advances in “omics” methods have shed some light in the molecular structure of cephalotoxins. There are reports of cephalotoxins being complex glycoproteins that take part in a myriad of novel compounds being produced by the salivary glands. Still, there is no consensus of cephalotoxins being a conserved form of proteins. As Blue Biotechnology and marine bioprospecting for novel bioreactives are gaining momentum, the present review will provide the state-of-the-art on cephalotoxins, highlighting old and new research and existing gaps in the current knowledge.

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“…According to diet, gastropods can be herbivorous, carnivorous, and omnivorous, and their feeding strategies are also very diversified including grazing, suspension-feeding, predation, and even parasitism [3]. T. mutabilis is a scavenger gastropod, feeding on carrion in the adult stage [2,4].…”

Section: Introductionmentioning

confidence: 99%

Hazard Identification Related to the Presence of Vibrio spp., Biogenic Amines, and Indole-Producing Bacteria in a Non-Filter Feeding Marine Gastropod (Tritia mutabilis) Commercialized on the Italian Market

Serratore

Bignami

Ostanello

et al. 2021

Foods

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Tritia mutabilis is a carrion-feeder edible marine gastropod with an open circulatory system. Therefore, biological, and chemical contaminants associated with the feed can reach all body tissues. The aim of the present study was to investigate the possible association of these characteristics with some food safety hazards. Vibrio spp. load, and the prevalence of pathogenic V. parahaemolyticus, V. vulnificus, and V. cholerae, were investigated. Moreover, biogenic amines (BAs) and indole-producing bacteria (IPB), markers of seafood decomposition, were quantified for the first time in an edible carrion-feeder. Overall, 49 batches were analyzed (38 from retail, and 11 from primary production). The Vibrio spp. load resulted of 5.64 ± 0.69 log10 CFU g−1 at retail, and 5.27 ± 0.74 at harvest but all batches resulted negative for pathogenic Vibrio. Histamine, putrescine, cadaverine, and tyramine were detected both at harvest and at the retail level. Their sum (BAs Index) showed a mean value of 50.45 and 65.83 mg Kg−1 in batches at harvest and at retail, respectively. IPB were detected at harvest and upon refrigeration for three days (T1–T3). The mean load resulted in 2.52 ± 0.85 log10 MPN g−1 at T0, 3.31 ± 1.23 at T3 in batches immediately refrigerated, and 3.22 ± 1.18 at T3 in batches previously immersed in clean seawater. Our results contribute to identifying food-borne hazards for T. mutabilis that may be related to the retention of biogenic amines and indole-producing bacteria due to carrion feeding.

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Structure and function of the digestive system in molluscs

Cited by 44 publications

References 142 publications

Functional morphology of the glandular esophageal pouches of chitons (Mollusca, Polyplacophora)

Functional morphology of the glandular esophageal pouches of chitons (Mollusca, Polyplacophora)

Cephalotoxins: A Hotspot for Marine Bioprospecting?

Hazard Identification Related to the Presence of Vibrio spp., Biogenic Amines, and Indole-Producing Bacteria in a Non-Filter Feeding Marine Gastropod (Tritia mutabilis) Commercialized on the Italian Market

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