Tautomeric transition between wobble A·C DNA base mispair and Watson–Crick-like A·C* mismatch: microstructural mechanism and biological significance

2015 ◽  
Vol 17 (23) ◽  
pp. 15103-15110 ◽  
Author(s):  
Ol'ha O. Brovarets' ◽  
Dmytro M. Hovorun
Keyword(s):  
Biological Significance ◽  
Dna Biosynthesis ◽  
Dna Base ◽  
Microstructural Mechanism

The A·C(w) → A·C*(WC) tautomerization via the DPT determines the origin of the spontaneous point AC/CA incorporation errors during DNA biosynthesis.

scholarly journals Where Quantum Biochemistry Meets Structural Bioinformatics: Excited Conformationally-Tautomeric States of the Classical A·T DNA Base Pair

2021 ◽  
Author(s):  
Ol’ha O. Brovarets’ ◽  
Kostiantyn S. Tsiupa ◽  
Dmytro M. Hovorun
Keyword(s):  
Base Pair ◽  
Biological Significance ◽  
Structural Bioinformatics ◽  
The Novel ◽  
Base Pairs ◽  
Dna Base ◽  
Dna Base Pair ◽  
First Time ◽  
Energy Hypersurface ◽  
Shed Light

This Chapter summarizes recent quantum-chemical (QM) investigations of the novel conformational and tautomeric states on the potential energy hypersurface of the classical A·T/A·U nucleobase pairs. For the first time, it was observed 28 local minima for each base pair excluding enantiomers - planar, non-planar base pairs and structures with wobble geometry. Considered excited conformationally-tautomeric states of the classical A·T DNA base pair have been revealed in the Nucleic Acid Database by structural bioinformatics. These data shed light on the biological significance of the unusual A·T/A·U nucleobase pairs for the functioning of the nucleic acids at the quantum level.

Microstructural morphology of sphingolipid dispersions as investigated by freeze-fracture EM

1995 ◽  
Vol 53 ◽  
pp. 944-945
Author(s):  
Vitthal S. Kulkarni ◽  
Wayne H. Anderson ◽  
Rhoderick E. Brown
Keyword(s):  
Acyl Chain ◽  
Biological Significance ◽  
Freeze Fracture ◽  
Fatty Acyl ◽  
Fatty Acyl Moiety ◽  
Aqueous Dispersions ◽  
Head Groups ◽  
Lipid Species ◽  
Microstructural Morphology ◽  
Layer Chromatography

The biological significance of the sphingomyelins (SM) and monoglycosylated sphingolipids like galactosylceramides (GalCer) are well documented Our recent investigation showed tubular bilayers in the aqueous dispersions of N-nervonoyl GalCer [N-(24:lΔ15,cls) GalCer] (a major fatty acyl moiety of natural GalCer). To determine the influence of lipid head groups on the resulting mesophasic morphology, we investigated microstructural self-assemblies of N-nervonoyl-SM [N-(24:1 Δ15,cls) SM; the second most abundant sphingomyelin in mammalian cell membranes], 1- palmitoyl-2-nervonoyl phosphatidylcholine [PNPC] (the lipid species with the same acyl chain configuration as in N-(24: 1) GalCer) and also compared it with egg-SM by freeze-fracture EM.Procedures for synthesizing and purifying N-(24:1) GalCer, N-(24:1) SM, and PNPC have been reported . Egg-SM was purchased from Avanti Polar Lipids, Alabaster AL. All lipids were >99% pure as checked by thin layer chromatography. Lipid dispersions were prepared by hydrating dry lipid with phosphate buffer (pH 6.6) at 80-90°C (3-5 min), vigorously vortexing (1 min) and repeating this procedure for three times prior to three freeze-thaw cycles.

Ultrastructural Localization Study of Carcinoembryonic Antigen (CEA) in Gastric Cancer: Immunoelectron Microscopic Observation

1990 ◽  
Vol 48 (3) ◽  
pp. 252-253
Author(s):  
Dong Yuming ◽  
Yang Guanglin ◽  
Wu Jifeng ◽  
Chen Xiaolin
Keyword(s):  
Gastric Cancer ◽  
Intestinal Metaplasia ◽  
Cancer Cells ◽  
Microscopic Observation ◽  
Biological Significance ◽  
Ultrastructural Localization ◽  
Mucinous Carcinoma ◽  
Surface Glycoprotein ◽  
Tubular Adenocarcinoma ◽  
Pap Method

On the basis of light microscopic observation, the ultrastructural localization of CEA in gastric cancer was studied by immunoelectron microscopic technique. The distribution of CEA in gastric cancer and its biological significance and the mechanism of abnormal distribution of CEA were further discussed.Among 104 surgically resected specimens of gastric cancer with PAP method at light microscopic level, the incidence of CEA(+) was 85.58%. All of mucinous carcinoma exhibited CEA(+). In tubular adenocarcinoma the incidence of CEA(+) showed a tendency to rising with the increase of degree of differentiation. In normal epithelia and intestinal metaplasia CEA was faintly present and was found only in the luminal surface. The CEA staining patterns in cancer cells were of three types--- cytoplasmic, membranous and weak reactive type. The ultrastructural localization of CEA in 14 cases of gastric cancer was studied by immunoelectron microscopic technique.There was a little or no CEA in the microvilli of normal epithelia. In intestinal metaplasia CEA was found on the microvilli of absorptive cells and among the mucus particles of goblet cells. In gastric cancer CEA was also distributed on the lateral and basal surface or even over the entire surface of cancer cells and lost their polarity completely. Many studies had proved that the alterations in surface glycoprotein were characteristic changes of tumor cells. The antigenic determinant of CEA was glycoprotein, so the alterations of tumor-associated surface glycoprotein opened up a new way for the diagnosis of tumors.

RIBONUCLEOPROTEIN PARTICLES CONTAINING mRNA and pre-mRNA

1973 ◽  
Vol 74 (Suppl) ◽  
pp. S130-S167 ◽  
Author(s):  
O. P. Samarina ◽  
E. M. Lukanidin ◽  
G. P. Georgiev
Keyword(s):  
Structural Organization ◽  
General Scheme ◽  
Biological Significance ◽  
Mrna Transport ◽  
Ribonucleoprotein Particles ◽  
Mrna Precursor

ABSTRACT This paper is a review of the data concerning the nature, structural organization, properties and biological significance of the particles, containing mRNA and pre-mRNA (precursor of mRNA), i. e., (1) nuclear pre-mRNA-containing particles (2) free cytoplasmic mRNP (ribonucleoproteins), or informosomes (3) polysome-bound mRNP. Some new data on the comparison of nuclear and cytoplasmic particles, the nature of poly A-containing structures, involvement of informofers in Adenovirusspecific RNA transfer are presented. The general scheme of mRNA transport from nucleus to cytoplasm is discussed.

Recent Rapid Climate Changes in Antarctic and their Influence on Low Diversity Ecosystems

2010 ◽  
Vol 17 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Katarzyna J. Chwedorzewska
Keyword(s):  
Environmental Variables ◽  
Climate Changes ◽  
Biological Significance ◽  
Global Changes ◽  
Factors Affecting ◽  
Low Diversity ◽  
Main Factors ◽  
The Antarctic ◽  
High Diversity ◽  
Temperature Water

ABSTRACTThe geographic position, astronomic factors (e.g. the Earth’s maximum distance from the Sun during winter), ice cover and altitude are the main factors affecting the climate of the Antarctic, which is the coldest place on Earth. Parts of Antarctica are facing the most rapid rates of anthropogenic climate change currently seen on the planet. Climate changes are occurring throughout Antarctica, affecting three major groups of environmental variables of considerable biological significance: temperature, water, UV-B radiation.Low diversity ecosystems are expected to be more vulnerable to global changes than high diversity ecosystems

ECOLOGICAL SIGNIFICANCE OF PHEROMONES

2020 ◽  
Vol 6 (2) ◽  
pp. 64-68
Author(s):  
Nondira Khondhodjayeva ◽  
◽  
Nurmamat Rajabov ◽  
Keyword(s):  
Biological Significance ◽  
Ecological Significance ◽  
Definition Of

This article reveals the essence of the concept of "pheromones" and their biological significance. In the article variants of their application in agriculture for struggle against insects-pests are presented. The definition of term and classification of pheromones and their types are given: feromons of insects, feromons of fish, feromons of vertebrates, feromons of humans, fermons of plants, sexual feromons, anxiety feromons, trace feromons, epidemic feromons and their functions and significance for the representative's organism and the environment as a whole

The biological significance of mtNOS modulation

10.2741/2124 ◽  
2007 ◽  
Vol 12 (1) ◽  
pp. 1041 ◽  
Author(s):  
María, C. Carreras
Keyword(s):  
Biological Significance
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