96,591 research outputs found
Agata Miklavc, Violin
Claire de lune; La plus que lente; La fille aux cheveux de lin / Claude Debussy; Tzigane / Maurice Ravel; Piano Trio in G major / Claude Debuss
Negotiation of meaning in outside of the classroom group assignments: accounting for the how to understand the what of future mathematics teachers' learning
In this paper we illustrate how Wenger’s theory of social learning can be used to account for phenomena of future teachers change in settings that are not usually studied, namely group work that future teachers do as they work on class assignments outside of class. We describe how we adapted Wenger’s theory to the exploration of future mathematics teachers’ learning and illustrate how the analysis of the audio taped interaction of a group of future teachers working out-side the classroom generated conjectures that help to explain their didactic knowledge development
\u3cem\u3eTetrahymena thermophila\u3c/em\u3e Lack a Homologue of the Caenorhabditis Elegans Lin-4 miRNA
The netrin family of proteins was first discovered because of their role in axonal guidance during development. Netrin homologues are important developmental signals in organisms ranging from vertebrates to the nematode, Caenorhabditis elegans, and netrin-like proteins have even been found in the ciliated protozoan, Tetrahymena thermophila. Since the lin-4 miRNA regulates netrin signaling in C. elegans, we hypothesized that a lin-4 homologue might exists in Tetrahymena thermophila. In order to test this hypothesis, we purified total miRNA from T. thermophila, used this miRNA to make cDNA, then used RT-PCR to quantitate the amount of lin-4 specific cDNA we obtained. Our sample was positive for total cDNA, but not for the lin-4 cDNA specifically, suggesting that this miRNA may not have a homologue in Tetrahymena
Evolutionary Conservation of the Heterochronic Pathway in C. elegans and C. briggsae
Heterochronic genes control the sequence and timing of developmental events during four larval stages of Caenorhabitis nematodes. Mutations in these genes may cause skipping or reiteration of developmental events.
C. briggsae is a close relative of C. elegans. These species have similar morphology and share the same ecological niche. C. briggsae undergoes the same developmental pathway consisting of four larval stages before reaching adulthood. It also has the same set of heterochronic genes.
Lin-28 is one of the heterochronic genes that also exists in other animals from flies to humans. It conservatively blocks the maturation of let-7 miRNA, the process is generally associated with the stem cell state. lin-28 is silenced as cells differentiate.
C. elegans mutants of lin-28 have a reduced number of seam cells and precocious alae. Despite the highly conserved protein sequence, C. briggsae develop a distinct phenotype when its lin 28 is disrupted. Worms did not have a characteristic vulval development defect, they also became lethargic and had a reduced fertility.
This observation led to a question of how conserved the heterochronic pathway is in close species
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