scholarly journals Screening for Insulin-Like/Mimetic Drugs Using Lower Eukaryotes

2019 ◽  
Vol 3 (2) ◽  
Keyword(s):  
Lower Eukaryotes

scholarly journals Glycogen Phosphorylase in Acanthamoeba spp.: Determining the Role of the Enzyme during the Encystment Process Using RNA Interference

2008 ◽  
Vol 7 (3) ◽  
pp. 509-517 ◽  
Author(s):  
Jacob Lorenzo-Morales ◽  
Jarmila Kliescikova ◽  
Enrique Martinez-Carretero ◽  
Luis Miguel De Pablos ◽  
Bronislava Profotova ◽  
...  
Keyword(s):  
Rna Interference ◽  
Cyst Wall ◽  
Glycogen Phosphorylase ◽  
Catalytic Domain ◽  
Present Report ◽  
Light And Electron Microscopy ◽  
Main Tool ◽  
Lower Eukaryotes ◽  
Free Glucose

ABSTRACT Acanthamoeba infections are difficult to treat due to often late diagnosis and the lack of effective and specific therapeutic agents. The most important reason for unsuccessful therapy seems to be the existence of a double-wall cyst stage that is highly resistant to the available treatments, causing reinfections. The major components of the Acanthamoeba cyst wall are acid-resistant proteins and cellulose. The latter has been reported to be the major component of the inner cyst wall. It has been demonstrated previously that glycogen is the main source of free glucose for the synthesis of cellulose in Acanthamoeba, partly as glycogen levels fall during the encystment process. In other lower eukaryotes (e.g., Dictyostelium discoideum), glycogen phosphorylase has been reported to be the main tool used for glycogen breakdown in order to maintain the free glucose levels during the encystment process. Therefore, it was hypothesized that the regulation of the key processes involved in the Acanthamoeba encystment may be similar to the previously reported regulation mechanisms in other lower eukaryotes. The catalytic domain of the glycogen phosphorylase was silenced using RNA interference methods, and the effect of this phenomenon was assessed by light and electron microscopy analyses, calcofluor staining, expression zymogram assays, and Northern and Western blot analyses of both small interfering RNA-treated and control cells. The present report establishes the role of glycogen phosphorylase during the encystment process of Acanthamoeba. Moreover, the obtained results demonstrate that the enzyme is required for cyst wall assembly, mainly for the formation of the cell wall inner layer.

The electroneutral cation-chloride cotransporters.

1998 ◽  
Vol 201 (14) ◽  
pp. 2091-2102 ◽  
Author(s):  
D B Mount ◽  
E Delpire ◽  
G Gamba ◽  
A E Hall ◽  
E Poch ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Gene Family ◽  
Molecular Identification ◽  
Membrane Topology ◽  
Cytoplasmic Domains ◽  
Transmembrane Segments ◽  
Novel Gene ◽  
Lower Eukaryotes ◽  
Homologous Genes ◽  
Cation Chloride Cotransporters

Electroneutral cation-chloride cotransporters are widely expressed and perform a variety of physiological roles. A novel gene family of five members, encompassing a Na+-Cl- transporter, two Na+-K+-2Cl- transporters and two K+-Cl- cotransporters, encodes these membrane proteins; homologous genes have also been identified in a prokaryote and a number of lower eukaryotes. The cotransporter proteins share a common predicted membrane topology, with twelve putative transmembrane segments flanked by long hydrophilic N- and C-terminal cytoplasmic domains. The molecular identification of these transporters has had a significant impact on the study of their function, regulation and pathophysiology.

The Nucleolus of Dictyostelium and Other Lower Eukaryotes

2013 ◽  
pp. 79-94 ◽  
Author(s):  
Andrew Catalano ◽  
Danton H. O’Day
Keyword(s):  
Lower Eukaryotes

Myosin I

1997 ◽  
Vol 273 (2) ◽  
pp. C347-C359 ◽  
Author(s):  
L. M. Coluccio
Keyword(s):  
Phosphorylation Site ◽  
Mass Range ◽  
Biochemical Properties ◽  
Actin Binding ◽  
Sequence Analyses ◽  
Heavy Chains ◽  
Amino Terminal ◽  
Lower Eukaryotes ◽  
Myosin I ◽  
Present Understanding

The class I myosins are single-headed, actin-binding, mechanochemical “motor” proteins with heavy chains in the molecular mass range of 110-130 kDa; they do not form filaments. Each myosin I heavy chain is associated with one to six light chains that bind to specific motifs known as IQ domains. In vertebrate myosin I isoforms, the light chain is calmodulin, which is thought to regulate motor activity. Proteins similar to calmodulin are associated with myosin I isoforms from lower eukaryotes. Some myosin I isoforms from lower eukaryotes are regulated by phosphorylation; however, the phosphorylation site is not present in vertebrate myosin I isoforms. Based on sequence analyses of the amino terminal “head” domains, myosin I can be subdivided into several subclasses. Analyses of the biochemical properties of the isolated molecules and localization studies support the proposal of roles for these molecules in intracellular trafficking and changes in membrane structure. Our present understanding of the properties of these molecules and their proposed roles is reviewed here.

scholarly journals Fission Yeast Rad51 and Dmc1, Two Efficient DNA Recombinases Forming Helical Nucleoprotein Filaments

2005 ◽  
Vol 25 (11) ◽  
pp. 4377-4387 ◽  
Author(s):  
Synthia Sauvageau ◽  
Alicja Z. Stasiak ◽  
Isabelle Banville ◽  
Mickaël Ploquin ◽  
Andrzej Stasiak ◽  
...  
Keyword(s):  
Reca Protein ◽  
Strand Break ◽  
Strand Exchange ◽  
Exchange Reactions ◽  
Single Stranded Dna ◽  
Strand Breaks ◽  
Lower Eukaryotes ◽  
Dna Double Strand Break ◽  
Dna Strand Exchange ◽  
Dna Strand

ABSTRACT Homologous recombination is important for the repair of double-strand breaks during meiosis. Eukaryotic cells require two homologs of Escherichia coli RecA protein, Rad51 and Dmc1, for meiotic recombination. To date, it is not clear, at the biochemical level, why two homologs of RecA are necessary during meiosis. To gain insight into this, we purified Schizosaccharomyces pombe Rad51 and Dmc1 to homogeneity. Purified Rad51 and Dmc1 form homo-oligomers, bind single-stranded DNA preferentially, and exhibit DNA-stimulated ATPase activity. Both Rad51 and Dmc1 promote the renaturation of complementary single-stranded DNA. Importantly, Rad51 and Dmc1 proteins catalyze ATP-dependent strand exchange reactions with homologous duplex DNA. Electron microscopy reveals that both S. pombe Rad51 and Dmc1 form nucleoprotein filaments. Rad51 formed helical nucleoprotein filaments on single-stranded DNA, whereas Dmc1 was found in two forms, as helical filaments and also as stacked rings. These results demonstrate that Rad51 and Dmc1 are both efficient recombinases in lower eukaryotes and reveal closer functional and structural similarities between the meiotic recombinase Dmc1 and Rad51. The DNA strand exchange activity of both Rad51 and Dmc1 is most likely critical for proper meiotic DNA double-strand break repair in lower eukaryotes.

Surface proteinaceous fibrils (fimbriae) on filamentous fungi

1988 ◽  
Vol 66 (12) ◽  
pp. 2474-2484 ◽  
Author(s):  
R. B. Gardiner ◽  
A. W. Day
Keyword(s):  
Filamentous Fungi ◽  
Surface Antigens ◽  
Surface Proteins ◽  
Diverse Group ◽  
Ustilago Violacea ◽  
Lower Eukaryotes

Proteinaceous fibrils (fimbriae) of 4–10 nm diam. have been described in several lower eukaryotes, including yeast-like fungi and certain algae. Antibodies prepared against the fimbriae of Ustilago violacea cross react with antigens present on the surface of these same organisms. In this paper we extend these observations to a diverse group of filamentous fungi, representing the major groups. These fungi also produce surface fibrils of 6–10 nm diam. and have surface antigens that cross react with the antibodies of U. violacea fimbriae. We conclude that surface proteins of a conserved type are common in the lower eukaryotes and that these may be manifested as surface fibrils of 4–10 nm diam. In some organisms these are extruded as numerous very long fimbriae (up to 30 μm); in others they may remain largely embedded in the wall or appear as a short fringe or as sparse longer fibrils.

Genetic analysis of ion channels of prokaryotes and lower eukaryotes

1992 ◽  
Vol 2 (5) ◽  
pp. 780-784 ◽  
Author(s):  
Robin R. Preston ◽  
Yoshiro Saimi ◽  
Boris Martinac ◽  
Ching Kung
Keyword(s):  
Ion Channels ◽  
Genetic Analysis ◽  
Lower Eukaryotes
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