1,721,016 research outputs found
The Fruit Fly Drosophila as a Powerful Tool in Teaching Life Sciences in Middle and High School Classrooms
Full text linkLiving organisms can be used as important didactic tools for students, and we report here for the first time the evaluation of a scientific laboratory on Drosophila. The aim of this work is to attract more students to wards science disciplines and a real appreciation for animal kingdom. We aimed to capture students’ interest, develop important educational experiences, and promote the basic and integrated science process skills that are involved in scientific inquiry, including direct contact to a living or ganism and authentic research on Drosophila melanogaster. We performed this experience in non-selective middle (100 students) and high school classrooms (200 students). The practical activities were carried out over three months. Initially, we decided to make homemade fly traps to catch flies, so that students could observe, recognize and have a direct contact with Drosophila . Several experiences were performed, such as the evaluation of different methods for immobilizing flies, and the observation of life cycle, sexual dimorphism, Drosophila mutants plus several species of Drosophilidae. Moreover, students prepared a procedure for fly food, and a method for anesthetizing flies. With sample questionnaires, we obtained a survey of the experiences and so we ob served a general agreement and a broad consensus (82 %), since students considered the experiences very stimulating. As a final result we obtained that students improved their attitudes towards science
Expression study of an alpha-l-fucosidase gene in the Drosophilidae family
No full textThe plasma membrane of Drosophila (Sophophora) melanogaster spermatozoa contains an alpha-l-fucosidase that might be involved in fertilization by interacting with alpha-l-fucose residues on the micropyle of the eggshell. D. (S.) melanogaster has a single gene called CG6128 or Fuca encoding for a putative alpha-l-fucosidase. Two transcripts have been annotated, RA of 3514 bp, and RB of 1673 bp. While both transcripts encode an alpha-l-fucosidase, RA contains an upstream open reading frame, translated into a polypeptide containing a predicted BTB/POZ domain. We demonstrate that Fuca is expressed in male and female germ lines. RT-PCR analysis indicated a broader tissue expression. Homologous genes are expressed in the same tissues in several drosophilid flies belonging to the genera Drosophila and Scaptodrosophila. However, the long transcript is restricted to species belonging to the subgenus Sophophora. The presence of two transcripts in species of the subgenus Sophophora and only one in species belonging to the subgenus Drosophila might be related to the phylogenetic relationships of these subgenera. Immunofluorescence demonstrated that the gene product, localized to the sperm plasma membrane, is absent from Scaptodrosophila lebanonensis spermatozoa. These findings support the hypothesis that the enzyme is involved in the molecular events of primary gamete interactions that are conserved among drosophilids belonging to Drosophila genus
Identification, characterization and expression of sperm molecules potentially involved in gamete interactions in Diptera
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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 Drosophila
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
An α-L-fucosidase potentially involved in fertilization is present on Drosophila spermatozoa surface
No full textDrosophila is emerging as a model organism to investigate egg fertilization in insects and the possible conservation of molecular mechanisms of gamete interactions demonstrated in higher organisms. This study shows that the spermatozoa of several species of Drosophila belonging to the melanogaster group have a plasma membrane associated α-L-fucosidase with features in common with α-L-fucosidases from sperm of other animals, including mammals. The enzyme has been purified and completely characterized in D. ananassae, because of its stability in this species. The sperm α-L-fucosidase is an integral protein terminally mannosylated, with the catalytic site oriented toward the extracellular space. It has a M(r) of 256 kDa and a multimeric structure made up by subunits of 48 and 55 kDa. Enzyme characterization included kinetic properties, pI, optimal pH, and thermal stability. A soluble form of the enzyme similar to the sperm associated α-L-fucosidase is secreted by the seminal vesicles. Synthetic peptides designed from the deduced product of the D. melanogaster gene encoding an α-L-fucosidase were used to raise a specific polyclonal antibody. Immunofluorescence labeling of spermatozoa showed that the enzyme is present in the sperm plasma membrane overlying the acrosome and the tail. Lectin cytochemistry analysis of the egg surface indicated that α-L-fucose terminal residues are present on the chorion with a strongly polarized localization on the micropyle. The α-L-fucosidase of Drosophila sperm plasma membrane appears to be potentially involved in gamete recognition by interacting with its glycoside ligands present on the egg surface at the site of sperm entry
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