Albumen Gland Proteins Research Articles

Helix pomatia albumen gland water soluble protein extract as powerful antiaging agent.

Accounting for increasingly developed population aging and dramatic elevation of aging-related severe disorders worldwide, search of the efficient antiaging agents is becoming one of the urgent problems of contemporary biomedical science. The aim of current study was to reveal the potential protective effects of water-soluble proteins extracted from albumen gland of snails against aging processes. We evaluated the antioxidant effect of the extract in 20 older adult rats in vivo and on 60 human blood samples ex vivo at the cellular level under physiological and oxidative stress conditions using the methods of spectrophotometric analysis, two-photon imaging and cell viability assay. The in vivo animal experiments showed significant increase in the levels of catalase and superoxide dismutase in treated older adult rats, compared to non-treated group. The ex vivo studies involving three human groups (young, middle aged and older adult), demonstrated that the extract has no effect on the cell viability, moreover significantly increases the number of erythrocytes, decreases age-related oxidative stress and the percentage of hemolysis of erythrocytes by aging. Thus, the snails albumen gland protein extract can be considered as effective natural antioxidative antiaging agent in prevention of aging-related pathological processes associated with oxidative stress.

Molecular systematics of the Carinarion complex (Mollusca: Gastropoda: Pulmonata): a taxonomic riddle caused by a mixed breeding system

The original description of the slugs Arion (Carinarion) fasciatus, Arion (Carinarion) silvaticus and Arion (Carinarion) circumscriptus was based on subtle differences in body pigmentation and genital anatomy. However, body pigmentation in these slugs may be influenced by their diet, whereas the genital differences between the species could not be confirmed by subsequent multivariate morphometric analyses. Hence, the status of the three nominal morphospecies remains controversial, with electrophoretic studies based on albumen gland proteins and allozymes also providing conflicting results. These studies suggested that Carinarion species are difficult to reconcile with the biological species concept because there is evidence of interspecific hybridization in places where these predominantly self-fertilizing slugs apparently outcross. Therefore, in the present study, the three Carinarion species are evaluated under a phylogenetic species concept, using nucleotide sequences of the nuclear ribosomal internal transcribed spacer 1 (ITS-1) and the mitochondrial 16S rDNA. ITS-1 showed no species specific variation. However, 16S rDNA yielded five haplotype groups. Three of these grouped haplotypes by species, whereas the two others joined haplotypes of different species and included all haplotypes that were shared by species (22% of all haplotypes). Hence, the three nominal Carinarion species appear to be inconsistent with a phylogenetic species concept. The present data also confirmed that North American Carinarion populations are genetically impoverished and may be not sufficiently representative with respect to the taxonomy of Carinarion. In conclusion, we currently regard Carinarion as a single species-level taxon, whose taxonomically deceiving, correlated phenotypic and genetic intraspecific variation is caused by sustained self-fertilization.

Aplysia capsulin is localized to egg capsules and egg cordon sheaths and shares sequence homology with Drosophila dec-1 gene products

Differential library screening of an albumen gland cDNA library, Western blot analysis, protein expression, immunolocalization studies, comparative genomics, and secretion assays identified a major Aplysia californica albumen gland protein (‘capsulin’) that is localized to egg capsules and to the sheaths of the egg cordon. Capsulin shared sequence homology with eggshell proteins encoded by the Drosophila dec-1 gene. The 1790-amino acid A. californica precursor contains 17 repeat sequences that are flanked by basic residue processing sites. The numerous proteolytic processing sites may facilitate the breakdown of capsulin prior to when veliger larvae break out of egg capsules as free-swimming larvae. An Aplysia brasiliana capsulin repeat sequence was 97% identical to its A. californica homolog. Capsulin fragments were not detected in the eluates of egg cordons, suggesting that capsulin is not a candidate water-borne pheromone precursor.

Aplysia seductin is a water-borne protein pheromone that acts in concert with attractin to stimulate mate attraction

Mate attraction in Aplysia involves the long-distance water-borne protein pheromones attractin, enticin, and temptin which are released during egg-laying. Other water-borne pheromones are predicted to act in concert with attractin, enticin, and temptin, but their identities were unknown. We recently identified a highly expressed Aplysia californica albumen gland gene ( Alb-23) that encoded a novel protein by differential library screening of an albumen gland cDNA library. To determine whether Alb-23 (‘seductin’) was a water-borne pheromone, we employed Western blot analysis, purification and expression of albumen gland proteins, immunolocalization studies, pheromone secretion assays, comparative genomics, and behavioral bioassays. Immunoreactive seductin was detected in eluates of egg cordons, indicating that seductin was secreted onto the cordon during egg laying. Aplysia brasiliana seductin was 94% identical to its A. californica homolog. In T-maze attraction assays, the combination of attractin and seductin was significantly attractive to potential mates, whereas either protein alone was not. Data from this and previous studies support the hypothesis that seductin is a water-borne protein pheromone that acts in concert with attractin, enticin, and temptin to attract Aplysia to form and maintain mating aggregations.

Characterization of Aplysia Enticin and Temptin, Two Novel Water-borne Protein Pheromones That Act in Concert with Attractin to Stimulate Mate Attraction

Mate attraction in Aplysia involves a long-distance water-borne signal (attractin) that is released during egg laying. Other pheromones are predicted to be released during egg laying that act in concert with albumen gland attractin to stimulate attraction, but their identities are unknown. To identify other candidate water-borne pheromones, we employed differential library screening of an albumen gland cDNA library, Northern blot analysis, purification, characterization, cloning, and expression of albumen gland proteins, matrix-assisted laser desorption ionization mass spectrometry, pheromone secretion assays, behavioral bioassays, immunolocalization studies, and comparative genomics. Four genes, Alb-23, Alb-24, Alb-69, and Alb-172, were highly expressed in Aplysia californica albumen glands and encoded novel proteins. The products of the Alb-24 ("enticin") and Alb-172 ("temptin") precursors were soluble and highly abundant in albumen gland extracts, whereas Alb-23 and Alb-69 were membrane-associated proteins. A comparative analysis showed that the predicted Aplysia brasiliana enticin and temptin proteins were 90 and 91% identical, respectively, to their A. californica homologs. T-maze attraction bioassay studies have previously demonstrated that egg cordons alone are attractive to Aplysia but that attractin alone is not. In the present study, however, the combination of attractin, enticin, and temptin was found to be significantly attractive to potential mates and doubled the number of animals attracted to this stimulus compared with control animals. The combined data strongly suggest that enticin and temptin are novel candidate water-borne protein pheromones that act in concert with attractin to attract Aplysia to form and maintain egglaying and mating aggregations.

Cloning and characterization of a candidate nutritive glycoprotein from the albumen gland of the freshwater snail, Helisoma duryi (Mollusca: Pulmonata)

Abstract. The albumen gland is a female accessory sex gland that synthesizes and secretes perivitelline fluid around pulmonate eggs. The perivitelline fluid is composed of mainly galactogen and proteins, and is thought to provide nourishment to the embryos during development. We have previously identified the major secretory protein of the albumen gland of the freshwater snail Helisoma duryi as a native glycoprotein of ∼288 kDa, consisting of four 66‐kDa subunits. In this study, the major albumen gland protein in H. duryi was purified, cloned, and the full‐length cDNA sequence determined. Nucleotide sequence analysis revealed that the albumen gland protein (HdAGP) shared 83% identity with a partial cDNA sequence from a developmentally regulated albumen gland protein in Biomphalaria glabrata. The HdAGP mRNA was detected by RT‐PCR in the albumen gland, ovotestis, mantle and digestive gland. SDS‐PAGE analysis of the albumen gland protein in egg masses at different stages of development showed that the amount of HdAGP steadily decreased during embryogenesis, suggesting its possible catabolism by the developing embryos. Protein domain searches suggested that the HdAGP shared limited sequence identity, and adopted a similar three‐dimensional conformation to the bactericidal, permeability increasing, protein family, raising the possibility of a potential bactericidal function for this important reproductive/developmental protein.

Immunochemical confirmation of migration of albumen gland proteins to the egg of the land snail, Euhadra: Analysis of the proteins by two-dimensional gel electrophoresis and Western blotting method.

To confirm the migration of proteins from the albumen gland to the egg of the land snail, Euhadra, the soluble proteins extracted from albumen glands and eggs of E. peliomphala, E. subnimbosa and E. quaesita were analyzed immunochemically.The major polypeptide groups (named No. 8 and 9 polypeptide groups on the polypeptide map) of soluble proteins extracted from the albumen gland of E. peliomphala were purified and used to immunize rabbits. The specific antibodies against the albumen gland proteins (anti-AG) were purified from the antiserum. The soluble proteins extracted from the albumen glands and the eggs of E. peliomphala, E. subnimbosa and E. quaesita were analyzed by O'Farrell's two-dimensional gel electrophoresis and Western blotting method with anti-AG. The anti-AG reacted not only with the two polypeptide groups, which were the same as the immunogens used, but also with another polypeptide group (named No. 14 polypeptide group on the polypeptide map) of all the samples tested. These results support strongly the migration of these polypeptide groups from the albumen gland to egg in Euhadra.

An albumen gland protein polymorphism in the terrestrial slug Arion owenii

Arion owenii is reported to be polymorphic for albumen gland proteins as resolved with vertical polyacrylamide gel electrophoresis. It is the first time that such a variation has been demonstrated in the subgenera Kobeltia and Carinarion. As the observed polymorphism may distinguish populations, it is suggested that geographically isolated populations of A. owenii may represent distinct forms or genetic strains.

Comparative electrophoretic analyses of three European Carinarion species (Mollusca, Pulmonata, Arionidae)

Digestive gland esterases and albumen gland proteins of Arion (Carinarion)fasciatus, A. (C.) circumscriptus, A. (C.)silvaticus, A. (Kobeltia)hortensis, A. (K.) distinctus and A. (K.)intermedius were studied using vertical polyacrylamide gel electrophoresis (PAGE) and isoelectric focusing (IEF). Each of the three Carinarion forms revealed characteristic and nearly monomorphic electrophoretic profiles. Yet some variation was also observed. Within each form the mean intraspecific similarities, calculated from IEF profiles, were high in comparison with similar figures for A. hortensis and A. distinctus. The interspecific similarities, however, were low and of about the same magnitude as those of the Kobeltia species. These results are discussed in the light of the reproductive biology of the Carinarion spp. It seems convenient to retain the three names A. fasciatus, A. circumscriptus and A. silvaticus, even though these do not necessarily refer to actual biological species.