Geetha Vasanthakumar, Gowri Chandrakasan and G.Krishnan: A comparative study of the composition of the collagens of the foot of two lamellibranch molluscs occurring in different habitats, J. Biosci., Vol.2, No 4, December 1980
A comparative study of the collagen of the foot of Lamellidens Sp. and that of the unmodified Mytilus edulis shows marked differences in physical properties, amino acid composition and in the degree of stabilization. But both conform to type I collagen of vertebrates. In these respects, the latter shows agreement with the features characteristic of byssus collagen, which is highly crosslinked, involving dimers and trimers of tyrosine. It is suggested that such differences may reflect the different functions of the organs concerned, the foot of Lamellidens being a locomotary organ of the animal, while the foot of Mytilus edulis is modified for anchorage of the animal. The vertigial part though not morphologically modified shows the essential compositional characteristics of the byssus being a mere remanant of it.
C. Palpandi, P. Ramasamy, T. Rajinikanth, S. Vairamani and A. Shanmugam: Extraction of Collagen from Mangrove Archeaogastropod Nerita (Dostia) crepidularia Lamarck, 1822. American-Eurasian Journal of Scientific Research 5 (1): 23-30, 2010
Collagen is the most abundant protein of animal origin, comprising approximately 30% of total animal protein. There are at least 19 variants of collagen, named type I to XIX. Types I, II, III and V are the fibrous collagens. Type I collagen is found in all connective tissue, including bones and skins. It is a heteropolymer of two 1 chains and one 2 chain. It consists of one-third glycine, contains no tryptophan or cysteine and is very low in tyrosine and histidine. Guanidine hydrochloride to solubilize the part of collagen referred as GSC and then RS-AL (crude connective tissue fractions) digested with pepsin called PSC were extracted from the tissues of N. crepidularia. The GSC and PSC yields (on a dry weight basis) were 0.48% and 1.28% respectively. The FT-IR spectral analysis of the collagen extract from tissues of N. crepidularia showed more or less same number of peaks, lying within the same range of values of the commercial collagen (Human placenta collagen) used as a standard. These results suggest that collagen could be obtained effectively from the tissues of N. crepidularia
A.Bairati, M.Comazzi, M.Gioria: An ultrastructural study of connective tissue in mollusc integument: II. Gastropoda. Tissue & Cell, 2001 33 (5)
We studied the ultrastructure of the subepidermal connective tissue (SEC) in different zones of the integument in terrestrial, marine and freshwater gastropods (eight species). In all cases, the SEC was a layer of loose connective tissue between the basal membrane (BM) of the epidermis and the connective tissue of the deeper muscle layers. It was of monotonous structure and not differentiated into layers such as are found in mammalian dermis. The extracellular matrix (ECM) consisted of a network of collagen fibrils of variable diameter, with abundant anchoring devices and proteoglycans. In six species, variables quantities of haemocyanin were present within haemocoelic sinuses present in the SEC. The thickness and density of the BM varied from species to species, as well as within species in the various zones of integument. The ultrastructure of the lamina densa (LD) was indistinguishable from that of BM in bivalves and similar to that in mammals, although basotubules and double pegs were absent. An irregularly spaced lamina lucida was usually present and was often shot thorough with filaments and small protrusions of the LD that connected with epithelial plasma membrane or with hemidesmosomes. A lamina fibroreticularis was not present. LD protrusions characterize the connection between BM and the ECM of SEC. In the terrestrial gastropods, a spongy matrix with ultrastructure closely similar to LD occupied large tracts of the SEC. In the mantle region of Arion rufus, the integumental SEC contained large cavities filled with spherical concretions, probably representing rudiments of a shell. In the mantle where the integument contained abundant muscle fibres, the BM was thick and directly connected to the ECM of the SEC which consisted of compact laminae of collagen fibrils with abundant anchoring devices. Along the edge of the foot of Patella ulyssiponensis, the SEC contained a layer of paramyosinic muscle fibres adhering to the epidermis. No differences or gradations in integumental SEC structure could be related to the phylogenetic position of the species examined.
Nathalie Humbert-David, Subramaniam Chandrasekaran, Marvin L Tanzer, Robert Garrone: Laminin extraction and disorganization of collagen fibrils in snail muscles by EDTA treatment. Biol Cell (1995) 83
Snail muscles were extracted by a solution of EDTA ans electron microscopy showed that the extract contained dispersed, depolymerizedc ollagenf ibrils andc ross-shapelda minin-like structures.Thee xtracts were purified by ltracentrifugationf ollowed by two different procedures which enriched the content of laminin-likes tructures.T he laminin-relatedm oleculesd isplayedu niquep roperties when analyzed by biochemical, immunological and morphological methods. Electrophoretic patterns of the molecular form purified primarily by ion exchangec hromatography, resembledE HS-tumor laminin and displayeda cruciform shapew hen viewed by electron microscopy. Immunohistology, using antiserum obtained against the agarose gel-purified protein, showed that this laminin was primarily located in the extracellular matrix surrounding muscle fibers. Western blots using anti-EHS laminin antibody showed reaction of a 300 kDa subunit of this snail laminin. The protein obtained by another procedure, initially using gel filtration, followed by ion exchangec hromatography,a lso appearedto be a laminin. It had a collapsedc ruciform appearancew hen viewed by electron microscopy. It contained several different subunits, one of which, ca 300 kDa, reacted with anti-EHS-laminin antibody and with antisnail laminin antibody. In contrast, EHS laminin did not react with the anti-snail laminin antibody. The composite results suggest that at least two different forms of laminin are extractable from snail muscle and that they share molecular properties and immune determinants with mouse tumor laminin.
Tonar Z., A. Markos: Microscopy and Morphometry of Integument of the Foot of Pulmonate Gastropods Arion rufus and Helix pomatia. Acta Vet. Brno 2004, 73: 3-8
The aim of our work was to carry out morphometric analysis of histological sections through the foot of pulmonate gastropods with an output suitable as a data entry for its biomechanical scaledependent modelling. We studied serial histological sections of two samples of ventral surface of the foot of Helix pomatia and Arion rufus. The structure of smooth muscle cells was examined by transmission electron microscopy. The relative proportions of cardinal tissue constituents was calculated from the area of colour photomicrographs with constant magnification. Because of ventro-dorsal morphological anisotropy, the ventral foot was divided into two layers parallel with the body surface. These layers, though delimited arbitrarily, were morphologically well distinguished and presumably of diverse biomechanical properties. The relative area proportions in sections through the superficial/deep subepithelial layer of integument (mean percentage values ±SD, n = 30) were as follows: H. pomatia 38 ± 2.5/22 ± 1.5 of smooth muscle cells, 51 ± 3.4/28 ± 1.8 of collagen connective tissue, and 9 ± 0.6/48 ± 3.6 of haemocoelic sinuses. In A. rufus, the corresponding values were 31 ± 2.1/24 ± 1.6, 50 ± 3.3/36± 2.4, and 17 ± 1.1/26 ± 1.1, respectively. In H. pomatia, the maximal length of smooth muscle cells was 218 μm, the maximal transverse diameter of muscle cells was 6.1 μm, and the maximal depth of mucus glands in subepidermal layer was 462 μm. In A. rufus, the values were 220 μm, 6.0 μm, and 266 μm. The data described neither in/homogenity, nor directional distribution and anisotropy of the tissue constituents. The results can be used as qualified input parameters for a simplified biomechanical model of the gastropod integument.
P.Berillis, M.Hatziioannou, I.T.Karapanagiotidis and C.Neofitou: Morphological study of muscular tissue collagen of wild and reared Cornu aspersum (Müller, 1774). Molluscan Research, 2013 Vol. 33, No. 1, 6–13
Muscular tissue collagen fibrils’ diameter and period of reared and wild snails (Cornu aspersum) were measured in order to investigate the role of nutrition on the collagen.Wild adult individuals were collected from Crete (Greece) and compared with adult individual snails reared under laboratory conditions fed a formulated diet. Transmission electron microscope and image analysis algorithms were used in the study. Statistically significant differences between the diameters of the collagen fibrils in the reared and the wild snails were found, and the D-period of the fibrils differed.
Fabiana Rigona, Gustavo Mânicaa,Fátima Gumac, Matilde Achavala,Maria C. Faccioni-Heuser: Ultrastructural features of the columellar muscle and contractile protein analyses in different muscle groups of Megalobulimus abbreviatus (Gastropoda, Pulmonata). Tissue and Cell 42 (2010) 53–60
In Megalobulimus abbreviatus, the ultrastructural features and the contractile proteins of columellar, pharyngeal and foot retractor muscles were studied. These muscles are formed from muscular fascicles distributed in different planes that are separated by connective tissue rich in collagen fibrils. These cells contain thick and thin filaments, the latter being attached to dense bodies, lysosomes, sarcoplasmic reticulum,caveolae, mitochondria and glycogen granules. Three types of muscle cells were distinguished: T1 cells displayed the largest amount of glycogen and an intermediate number of mitochondria, suggesting the highest anaerobic metabolism; T2 cells had the largest number of mitochondria and less glycogen, which suggests an aerobic metabolism; T3 cells showed intermediate glycogen volumes, suggesting an intermediate anaerobic metabolism. The myofilaments in the pedal muscle contained paramyosin measuring between 40 and 80nm in diameter. Western Blot muscle analysis showed a 46-kDa band that corresponds to actin and a 220-kDa band that corresponds to myosin filaments. The thick filament used in the electrophoresis showed a protein band of 100 kDa in the muscles, which may correspond to paramyosin.