scholarly journals Plant secondary siRNA production determined by microRNA-duplex structure

2012 ◽  
Vol 109 (7) ◽  
pp. 2461-2466 ◽  
Author(s):  
P. A. Manavella ◽  
D. Koenig ◽  
D. Weigel
Keyword(s):  
Duplex Structure ◽  
Secondary Sirna

A Duplex Structure in Dense KSr2Nb5O15Ferroelectric Ceramics

2015 ◽  
Vol 474 (1) ◽  
pp. 99-104 ◽  
Author(s):  
Liangliang Liu ◽  
Feng Gao
Keyword(s):  
Duplex Structure

scholarly journals Thermal Stability Changes in Telomeric G-Quadruplex Structures Due to N6-Methyladenine Modification

Epigenomes ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 5 ◽  
Author(s):  
Ryohei Wada ◽  
Wataru Yoshida
Keyword(s):  
Thermal Stability ◽  
Base Pair ◽  
Genomic Dna ◽  
Biological Functions ◽  
Duplex Structure ◽  
Stacking Interaction ◽  
Hybrid Type ◽  
G Quadruplex ◽  
Melting Analysis ◽  
Thermal Stability Of

N6-methyladenine modification (m6dA) has recently been identified in eukaryote genomic DNA. The methylation destabilizes the duplex structure when the adenine forms a Watson–Crick base pair, whereas the methylation on a terminal unpaired adenine stabilizes the duplex structure by increasing the stacking interaction. In this study, the effects of m6dA modification on the thermal stability of four distinct telomeric G-quadruplex (G4) structures were investigated. The m6dA-modified telomeric oligonucleotide d[AGGG(TTAGGG)3] that forms a basket-type G4 in Na+, d[(TTAGGG)4TT] that forms a hybrid-type G4 in K+ (Form-2), d[AAAGGG(TTAGGG)3AA] that forms a hybrid-type G4 in K+ (Form-1), and d[GGG(TTAGGG)3T] that forms a basket-type G4 with two G-tetrads in K+ (Form-3) were analyzed. Circular dichroism melting analysis demonstrated that (1) A7- and A19-methylation destabilized the basket-type G4 structure that formed in Na+, whereas A13-methylation stabilized the structure; (2) A15-methylation stabilized the Form-2 G4 structure; (3) A15- and A21-methylations stabilized the Form-1 G4 structure; and (4) A12-methylation stabilized the Form-3 G4 structure. These results suggest that m6dA modifications may affect the thermal stability of human telomeric G4 structures in regulating the biological functions.

scholarly journals ELECTRON MICROSCOPE STUDIES ON THE DICTYOSOMES AND ACROBLASTS IN THE MALE GERM CELLS OF THE CRICKET

1956 ◽  
Vol 2 (4) ◽  
pp. 123-128 ◽  
Author(s):  
H. W. Beams ◽  
T. N. Tahmisian ◽  
R. L. Devine ◽  
Everett Anderson
Keyword(s):  
Electron Microscope ◽  
Golgi Apparatus ◽  
Electron Micrographs ◽  
Germ Cells ◽  
Light Microscope ◽  
Golgi Body ◽  
Duplex Structure ◽  
Male Germ Cells ◽  
Secondary Spermatocyte ◽  
A Chain

The dictyosome (Golgi body) in the secondary spermatocyte of the cricket appears in electron micrographs as a duplex structure composed of (a) a group of parallel double-membraned lamellae and (b) a group of associated vacuoles arranged along the compact lamellae in a chain-like fashion. This arrangement of ultramicroscopic structure for the dictyosomes is strikingly comparable to that described for the Golgi apparatus of vertebrates. Accordingly, the two are considered homologous structures. Associated with the duplex structure of the dictyosomes is a differentiated region composed of small vacuoles. This is thought to represent the pro-acrosome region described in light microscope preparations. In the spermatid the dictyosomes fuse, giving rise to the acroblast. Like the dictyosomes, the acroblasts are made up of double-membraned lamellae and associated vacuoles. In addition, a differentiated acrosome region is present which, in some preparations, may display the acrosome vacuole and granule. Both the dictyosomes and acroblasts are distinct from mitochondria.

scholarly journals Structural Properties of G,T-Parallel Duplexes

2010 ◽  
Vol 2010 ◽  
pp. 1-11 ◽  
Author(s):  
Anna Aviñó ◽  
Elena Cubero ◽  
Raimundo Gargallo ◽  
Carlos González ◽  
Modesto Orozco ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Structural Properties ◽  
Theoretical Calculations ◽  
Md Simulations ◽  
Theoretical Studies ◽  
Duplex Structure ◽  
Strong Stabilization ◽  
The Stability ◽  
The Impact

The structure of G,T-parallel-stranded duplexes of DNA carrying similar amounts of adenine and guanine residues is studied by means of molecular dynamics (MD) simulations and UV- and CD spectroscopies. In addition the impact of the substitution of adenine by 8-aminoadenine and guanine by 8-aminoguanine is analyzed. The presence of 8-aminoadenine and 8-aminoguanine stabilizes the parallel duplex structure. Binding of these oligonucleotides to their target polypyrimidine sequences to form the corresponding G,T-parallel triplex was not observed. Instead, when unmodified parallel-stranded duplexes were mixed with their polypyrimidine target, an interstrand Watson-Crick duplex was formed. As predicted by theoretical calculations parallel-stranded duplexes carrying 8-aminopurines did not bind to their target. The preference for the parallel-duplex over the Watson-Crick antiparallel duplex is attributed to the strong stabilization of the parallel duplex produced by the 8-aminopurines. Theoretical studies show that the isomorphism of the triads is crucial for the stability of the parallel triplex.

scholarly journals The Formation of the Secretory Granules in the Liver-cells of the Slug, Anadenus altivagus

1957 ◽  
Vol s3-98 (42) ◽  
pp. 235-240
Author(s):  
RAJINDER RISHI
Keyword(s):  
Secretory Granules ◽  
Liver Cells ◽  
Duplex Structure ◽  
Direct Transformation ◽  
Lipid Granules

The process of formation of secretory granules has been studied in the liver-cells of the slug, Anadenus altivagus, in fixed preparations. The following conclusions have been drawn. 1. The secretory granules, which are non-lipid in nature, are formed by direct transformation of the lipid granules. The lipid granules assume a duplex structure during this transformation. 2. The lipid granules, which are densely packed at the basal end of the cells, seem to arise from the tip-granules of the mitochondria. 3. The mitochondria are fibrillar and each of them shows one prominent granule at each tip. The mitochondria as well as their tip-granules are stainable with iron haematoxylin after Regaud, whereas the lipid granules are not.

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