17 research outputs found
Compactifiable classes of compacta
We introduce the notion of compactifiable classes -- these are classes of
metrizable compact spaces that can be up to homeomorphic copies ``disjointly
combined'' into one metrizable compact space. This is witnessed by so-called
compact composition of the class. Analogously, we consider Polishable classes
and Polish compositions. The question of compactifiability or Polishability of
a class is related to hyperspaces. Strongly compactifiable and strongly
Polishable classes may be characterized by the existence of a corresponding
family in the hyperspace of all metrizable compacta. We systematically study
the introduced notions -- we give several characterizations, consider
preservation under various constructions, and raise several questions.Comment: 32 pages, 1 figure, revised versio
The Minimal Proteome in the Reduced Mitochondrion of the Parasitic Protist Giardia intestinalis
The mitosomes of Giardia intestinalis are thought to be mitochondria highly-reduced in response to the oxygen-poor niche. We performed a quantitative proteomic assessment of Giardia mitosomes to increase understanding of the function and evolutionary origin of these enigmatic organelles. Mitosome-enriched fractions were obtained from cell homogenate using Optiprep gradient centrifugation. To distinguish mitosomal proteins from contamination, we used a quantitative shot-gun strategy based on isobaric tagging of peptides with iTRAQ and tandem mass spectrometry. Altogether, 638 proteins were identified in mitosome-enriched fractions. Of these, 139 proteins had iTRAQ ratio similar to that of the six known mitosomal markers. Proteins were selected for expression in Giardia to verify their cellular localizations and the mitosomal localization of 20 proteins was confirmed. These proteins include nine components of the FeS cluster assembly machinery, a novel diflavo-protein with NADPH reductase activity, a novel VAMP-associated protein, and a key component of the outer membrane protein translocase. None of the novel mitosomal proteins was predicted by previous genome analyses. The small proteome of the Giardia mitosome reflects the reduction in mitochondrial metabolism, which is limited to the FeS cluster assembly pathway, and a simplicity in the protein import pathway required for organelle biogenesis
Recommended from our members
Publisher Correction: Genetic tool development in marine protists: emerging model organisms for experimental cell biology.
An amendment to this paper has been published and can be accessed via a link at the top of the paper
Recommended from our members
Genetic tool development in marine protists: emerging model organisms for experimental cell biology
Abstract: Diverse microbial ecosystems underpin life in the sea. Among these microbes are many unicellular eukaryotes that span the diversity of the eukaryotic tree of life. However, genetic tractability has been limited to a few species, which do not represent eukaryotic diversity or environmentally relevant taxa. Here, we report on the development of genetic tools in a range of protists primarily from marine environments. We present evidence for foreign DNA delivery and expression in 13 species never before transformed and for advancement of tools for eight other species, as well as potential reasons for why transformation of yet another 17 species tested was not achieved. Our resource in genetic manipulation will provide insights into the ancestral eukaryotic lifeforms, general eukaryote cell biology, protein diversification and the evolution of cellular pathways
Genetic tool development in marine protists: emerging model organisms for experimental cell biology
Abstract: Diverse microbial ecosystems underpin life in the sea. Among these microbes are many unicellular eukaryotes that span the diversity of the eukaryotic tree of life. However, genetic tractability has been limited to a few species, which do not represent eukaryotic diversity or environmentally relevant taxa. Here, we report on the development of genetic tools in a range of protists primarily from marine environments. We present evidence for foreign DNA delivery and expression in 13 species never before transformed and for advancement of tools for eight other species, as well as potential reasons for why transformation of yet another 17 species tested was not achieved. Our resource in genetic manipulation will provide insights into the ancestral eukaryotic lifeforms, general eukaryote cell biology, protein diversification and the evolution of cellular pathways
Comprehensive sub-mitochondrial protein map of the parasitic protist Trypanosoma brucei defines critical features of organellar biology
Raw data from Figures 2, S2, and S3THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
Atomic Mappings Can Spoil Lightness of Open Mappings
. We study continua on which each nonconstant open mapping is light. W. Makuchowski asked if this property is preserved under atomic mappings. It is known that this is true under an additional assumption of arcwise connectedness of the domain continuum. We show that in general this is not true. 1. Introduction. It is known that each open mapping defined on an arc or on a simple closed curve is light, see [9, Theorems 1.2 and 1.3, p. 184]. These results have been extended in several ways. For example in [3, Theorem 5, p. 214] it is shown that if a domain space is locally dendritic and the range one has no isolated points, then each nonconstant open mapping is light. In particular, this is the case when the domain space is a continuum being a local dendrite. Obviously each local dendrite, as a locally connected continuum, is arcwise connected. In a further study of the subject, W. Makuchowski asked in [8, Question 2.6, p. 782] whether there is a non-arcwise connected continuum X suc..