Browsing by Subject "Carbohydrates"

Now showing 1 - 5 of 5
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    Carbohydrates and soluble lectins in the regulation of cell adhesion and proliferation
    (Murcia : F. Hernández, 1994) Zanetta, J.P.; Badache, A.; Maschke, S.; Marschal, P.; Kuchler, S.
    There is a large body of suggestions that complex carbohydrates play a role in the regulation of cell adhesion and cell proliferation. Many reports have emphasized that proteoglycans. glycoproteins or glycolipids are participating to cell adhesion mechanisms. The use of polyvalent anti-carbohydrate antibodies and plant lectins as well as the use of glycosy lation inhibitors suggested that cell proliferation can be nlodulated by surface carbohydrates. The dating experiment of Burger and Noonan (1970) showing restoration of contact inhibition of malignant cells by monovalent concanavalin A was a determining experiment. However, in the latter as in the others, no precise mechanism was demonstrated how carbohydrates can be involved in adhesion and proliferation. New insights were opened with the discovery of vertrebrate membrane-bound and soluble lectins. The latter generally display agglutinating activities in in vitro systems, suggesting that they were potential cell adhesion molecules, by forming bridges between cell surface carbohydrates. These polyvalent molecules may be also considered as clustering agents for their cell surface ligands, conseq~~entlgye nerating signals for cell proliferation andlor differentiation.
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    Confocal evaluation of native and induced lectin binding contributes to discriminate between lingual gland glycocomponents in quail
    (Murcia : F. Hernández, 2000) Bondi, A.M.; Gabrielli, M.G.; Accili, Daniela; Sabbieti, M.G.; Menghi, Giovanna
    A confocal analysis was performed on the quail (Coturnix coturnix japonica) lingual salivary glands where the carbohydrate chains were studied by lectin histochemistry. For this purpose, appropriate FITC- and TRITC-conjugates were used for double binding also accomplished with sialidase digestion. The glycosidic components of the quail lingual salivary glands were found to be heterogeneously distributed on the different secretory structures as well as on the single secretory elements of each adenomere. The rostra1 portion of the anterior lingual gland was found to only secrete neutral glycocomponents, characterized by terminal B-galactose, N-acetylgalactosamine and fucose residues in contrast to the caudal portion that was shown to be extremely heterogeneous and to produce sialylated glycoconjugates characterized by the terminal sequences sialic acid-B-galactose-N-acetylgalactosamine, sialic acid-13-galactose-N-acetylglucosamine,a nd sialic acida- N-acetylgalactosamine partly codistributed within secretory adenomeres. The posterior lingual gland was observed to be the major contributor to the secretion of salivary mucins containing sialoglycoconjugates with terminal sialic acid residues linked to B-galactose-Nacetylgalactosamine or a-N-acetylgalactosamine often located in distinct secretory elements.
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    Effective use of glucose rather than starch in formulated semimoist diets of common octopus (Octopus vulgaris)
    (Wiley, 2014-08-12) Cerezo Valverde, Jesús; Aguado Giménez, Felipe; Hernández, M. D.; García García, Benjamín; Sánchez Morillo-Velarde, María Piedad; Biología Celular e Histología
    The aim of the present work was to test the capacity of Octopus vulgaris to use carbohydrates supplied in three diets: a diet without added carbohydrates (diet C0: 500 g kg−1 water, 200 g kg−1 gelatine, 100 g kg−1 egg yolk powder, 50 g kg−1 freeze-dried Sardinella aurita and 150 g kg−1 freeze-dried Todarodes sagittatus) and two obtained by substituting 50 g kg−1 of T. sagittatus by glucose (diet GLU50) or by starch (diet STA50). The most stable and best-accepted diet was STA50 (SFR 1.26%BW day−1) although there were no significant differences in the growth rates obtained with the three diets: 10.12 g day−1, 9.37 g day−1 and 11.22 g day−1 for C0, GLU50 and STA50, respectively (P > 0.05). The feed efficiency indices were better for GLU50, of particular note being the protein productive value of 71.88% and a feed conversion ratio lower than 1. Protein and lipid digestibility were similar in all the three diets (96–98% for proteins and 85–94% for lipids), whereas carbohydrate digestibility was higher in GLU50 (98%) than in C0 (84%) and STA50 (0.33%). The content of carbohydrates increased in muscle and the digestive gland as a consequence of the increased carbohydrates intake.
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    Histological and histochemical observations in the stomach of the Senegal sole, Solea senegalensis
    (Murcia : F. Hernández, 2001) Arellano, J.M.; Storch, V.; Sarasquete, C.
    An histological and histochemical study was conducted on the stomach of adult Senegal sole, Solea senegalensis specimens. The stomach was made up of four distinct layers: mucosa, lamina propria-submucosa-, muscularis and serosa. Surface epithelial, glandular and rodlet cells were present in the mucosa. Cells of the columnar epithelium contained a basa1 nucleus. Numerous mitochondria, granular endoplasmic reticulum and Golgi apparatus consisting of severa1 parallel cisternae and vesicles were observed in the cytoplasm of these cells. The lysosomes were small, round and dense. The gastric glands were numerous in the pyloric and fundic regions but absent in the cardiac stomach. These glands were formed by two cell-types: light and dark cells. The light cells were characterised by numerous mitochondria, while dark cells had slightly fewer mitochondria and a tubulo-vesicular system. Rodlet cells similar to those observed in other teleostean fish were present among the epithelial cells. Although the epithelial cells of the mucosa contained a weak presence of neutral and acid mucopolysaccharides/mucosubstances, these substances were abundant in the lamina propria-submucosa. Proteins rich in arginine, lysine, cysteine and cystine were rarely present in the mucosa and lamina propriasubmucosa of stomach, while proteins rich in tyrosine were abundant in these layers. Acid phosphatase, and ATP-ase (pH 7.2 and 9.4) activities were detected in the mucosa and lamina propria-submucosa. Alkaline phosphatase activity was not detected.
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    Oogenesis in the bluefin tuna, Thunnus thynnus L. A histological and histochemical study
    (Murcia : F. Hernández, 2002) Sarasquete, C.; Cárdenas, S.; Gonzalez de Canales, M.L.; Pascual, E.
    Histology and histochemistry are useful tools to study reproductive mechanisms in fish and they have been applied in this study. In the bluefin tuna, Thunnus thynnus L., oocyte development can be divided into 4 principal phases based on the morphological features of developing oocytes and follicles. The primary growth phase includes oogonia and basophilic or previtellogenic oocytes classified as chromatin-nucleolus and perinucleolus stages. The secondary growth phase is represented by vitellogenic oocytes at early (lipid globule and yolk granule 1), mid (yolk granule 2) and late (yolk granule 3) vitellogenesis stages. The maturation phase involves postvitellogenic oocytes undergoing maturation process. During the spawning period, both postovulatory follicles, which indicate spawning, and atretic follicles can be distinguished in the ovary. Carbohydrates, lipids, proteins and specially those rich in tyrosine, tryptophan, cystine, arginine, lysine and cysteine, as well phospholipids and/or glycolipids and neutral glycoproteins were detected in yolk granules. Moreover, affinity for different lectins (ConA, WGA, DBA and UEA) was detected in vitellogenic oocytes (yolk granules, cortical alveoli, follicular layer and zona radiata), indicating the presence of glycoconjugates with different sugar residues (Mannose- Man- and/or Glucose -Glc-; N-acetyl-D-glucosamine- GlcNAc- and/or sialic acid- NANA-; N-acetyl-D-galactosamine- GalNAc-; LFucose -Fuc-). Histochemical techniques also demonstrated the presence of neutral lipids in globules (vacuoles in paraffin sections) and neutral and carboxylated mucosubstances in cortical alveoli. By using anti-vitellogenin (VTG) serum, immunohistochemical positive results were demonstrated in yolk granules, granular cytoplasm and follicular cells of vitellogenic oocytes. Calcium was also detected in yolk granules and weakly in follicular envelope. In females, the gonadosomatic index (GSI) increased progressively from May, during early vitellogenesis, until June during mid and late vitellogenesis, where the highest values were reached. Subsequently, throughout the maturation-spawning phases (July), GSI decreased progressively reaching the minimal values during recovering-resting period (October).