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Characterization and mapping of putative egg receptors on the surface of Drosophila melanogaster spermatozoa
No full textPlasma membrane association and characterization of Drosophila sperm surface glycosidases
No full textGlycoconjugates of the surface of the spermatozoa of Drosophila melanogaster: a qualitative and quantitative study
No full textThe important roles played by glycoconjugates in the recognition of gametes and in fertilization are well documented. In the present study, the nature and distribution of carbohydrate residues of the plasma membrane of spermatozoa of Drosophila melanogaster were characterized by use of FITC-conjugated lectins as probes. The plasma membrane bound agglutinins from Concanavalia ensiformis (Con A) and Pisum sativum (PSA), native and succinylated agglutinins from wheat germ (WGA and s-WGA), the A(4) isoform of agglutinin-I from Griffonia simplicifolia (GSA-I A(4)), and, to a lesser extent, the lectins from Dolichus biflorus (DBA), Lotus tetragonolobus (LTA), and Glycine maximus (SBA). Each lectin gave a specific pattern of binding. The extent of binding of Con A, WGA, s-WGA, and GSA-I A(4) over the acrosomal region was greater than over nonacrosomal regions, indicating the concentration of alpha-mannose/alpha-glucose, beta-N-acetylglucosamine, and alpha-N-acetylgalactosamine residues in this area of the plasma membrane. The surface of the sperm failed to react with lectins from Ricinus communis (RCA-I), Limulus polyphemus (LPA), and Limax flavus (LFA) and with the B-4 isoform of agglutinin-I from Griffonia simplicifolia-I (GSA-I B-4) The plasma membrane over the nucleus did not react with any of the lectins tested.
Quantitative analysis of binding of Con A, s-WGA, and GSA-I A(4) to spermatozoa showed that only Con A bound consistently to the sperm surface, showing high affinity for the acrosomal area of the plasma membrane. The other lectins tested bound only to limited and variably sized fractions of the total population of sperm. Therefore, only residues of alpha-mannose/alpha-glucose are a constitutive component of the plasma membrane, and they are characteristic of the acrosomal area. Con A can be used as a marker of the acrosome portion of sperm from Drosophila for visualization and assessment of acrosome status; labelling with FITC-conjugated Con A provides a simple and reliable method for visualization of the acrosome of Drosophila sperm that is otherwise detectable only by ultrastructural examination
Identification, characterization and expression of sperm molecules potentially involved in gamete interactions in Drosophila
No full textUltrastructural and cytochemical analysis of sperm dimorphism in Drosophila subobscura
No full textIn Drosophila subobscura the male produces two classes of motile spermatozoa that differ in total length and nucleus length, The significance of this within-ejaculate polymegaly is obscure, We have carried out an ultrastructural and cytochemical analysis of both sperm morphs to understand their possible role at fertilization, Computer-aided analysis was used to clarify the complex three-dimensional structure of the spermatozoa.
Short and long spermatozoa have a similar architecture, The axoneme is of the classic insect type and, together with the major mitochondrial derivative, runs for almost the whole sperm length, The axoneme ends just below the sperm apex with a centriole adjacent to the acrosome, Minor differences between the two types of sperm are related to acrosome size, nucleus morphology and relationship between nucleus and minor mitochondrial derivative.
Cytophotometry of Feulgen stained samples indicated that long and short spermatozoa contain a similar amount of DNA.
Both short and long spermatozoa are transferred and stored in the female upon mating, As they have similar ultrastructural and cytochemical characteristics, both sperm are potentially functional in egg penetration and karyogamy
Comparative and phylogenetic analysis of alpha-L-fucosidase genes
No full textFucosylated glycoconjugates play a role in a wide variety of biological processes, including immune responses, signal transduction, ontogenic events and pathogenesis of several human diseases. Alpha-L-fucosidases, which are responsible for their processing, have been demonstrated to be involved in lysosomal storage disease, inflammation, cystic fibrosis, cancer development and in the interactions between gametes in vertebrates as well as invertebrates. The sequence and comparative genomic analysis of these glycosyl hydrolases and the study of their evolutionary relationships appear therefore to be of considerable interest. In this work we carried out extensive similarity searches and comparative analyses to identify sequences encoding alpha-L-fucosidases. We have identified novel alpha-L-fucosidase coding sequences in worms, insects, sea urchin, ascidians, fish, chicken, amphibians, mammals and various bacteria resulting in a total of 39 alpha-L-fucosidase sequences. Two alpha-L-fucosidases that are present in all vertebrates likely reflect a distinct biological role for paralogous genes. Comparative sequence analysis of all metazoan alpha-L-fucosidases reveals a broad conservation of features, including the aspartate residue that constitutes the catalytic nucleophile. However, a cysteine which is thought to be part of the active site is also conserved in metazoa but not in arthropods, where it is replaced by an alanine. Phylogenetic analysis suggests a gene duplication event very early in metazoan evolution with the subsequent differential loss of isoforms in various metazoan lineages
Identification, characterization and expression of sperm molecules potentially involved in gamete interactions in Diptera
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