scholarly journals Synthesis of Glycosidic (β-1′′→6, 3′ and 4′) Site Isomers of Neomycin B and their Effect on RNA and DNA Triplex Stability

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 580
Author(s):  
Lotta Granqvist ◽  
Ville Tähtinen ◽  
Pasi Virta
Keyword(s):  
Profile Analysis ◽  
Starting Material ◽  
Protecting Group ◽  
Melting Profile ◽  
Straightforward Manner ◽  
Neomycin B ◽  
Glycosyl Donor ◽  
Dna Triplex ◽  
Uv Melting ◽  
Rna And Dna

Glycosidic (β-1′′→6, 3′ and 4′) site isomers of neomycin B (i.e., neobiosamine (β-1′′→6, 3′ and 4′) neamines) have been synthesized in a straightforward manner. Peracetylated neomycin azide was used as a common starting material to obtain neobiosamine glycosyl donor and 6, 3′,4′-tri-O-acetyl neamine azide that after simple protecting group manipulation was converted to three different glycosyl acceptors (i.e., 5,6,4′-, 5,3′,4′- and 5,6,3′-tri-O-acetyl neamine azide). Glycosylation between the neobiosamine glycosyl donor and the neamine-derived acceptors gave the protected pseudo-tetrasaccharides, which were converted, via global deprotection (deacetylation and reduction of the azide groups), to the desired site isomers of neomycin. The effect of these aminoglycosides on the RNA and DNA triplex stability was studied by UV-melting profile analysis.

Changes in The Cytochemical Properties Of Erythrocyte Nuclei Reactivated By Cell Fusion

1969 ◽  
Vol 4 (1) ◽  
pp. 71-87 ◽  
Author(s):  
L. BOLUND ◽  
N. R. RINGERTZ ◽  
H. HARRIS
Keyword(s):  
Hela Cell ◽  
Cell Fusion ◽  
Dry Mass ◽  
Nuclear Chromatin ◽  
Red Cell ◽  
Melting Profile ◽  
Nuclear Composition ◽  
Erythrocyte Nucleus ◽  
Rna And Dna ◽  
Deoxyribonucleoprotein Complex

When the nucleus of a chick erythrocyte is introduced into the cytoplasm of a HeLa cell it resumes the synthesis of RNA and DNA. This reactivation of the red cell nucleus is associated with an increase in volume and with changes in nuclear composition. These changes have now been studied by quantitative cytochemical techniques. During the process of reactivation the dry mass of the erythrocyte nucleus shows a marked increase which takes place largely before the replication of the DNA begins. Within 24 h of cell fusion, some erythrocyte nuclei already contain an increased amount of DNA, and 48 h after fusion many of them contain twice the normal diploid amount, thus indicating that they have replicated their DNA completely. The physical properties of the nuclear deoxyribonucleoprotein complex also change. The ability of the nuclear chromatin to bind acridine orange increases 4- to 5-fold well before the synthesis of DNA begins; and changes in the melting profile of the deoxyribonucleoprotein suggest that its structure is loosened. This view is also supported by the observation that the reactivity of the erythrocyte nuclei to the Feulgen stain is altered during the early stages of reactivation.

scholarly journals Rapid Detection Method for the Four Most Common CHEK2 Mutations Based on Melting Profile Analysis

2015 ◽  
Vol 19 (6) ◽  
pp. 419-425 ◽  
Author(s):  
Pawel Borun ◽  
Kacper Salanowski ◽  
Dariusz Godlewski ◽  
Jaroslaw Walkowiak ◽  
Andrzej Plawski
Keyword(s):  
Rapid Detection ◽  
Detection Method ◽  
Profile Analysis ◽  
Melting Profile

scholarly journals First total synthesis of kipukasin A

2017 ◽  
Vol 13 ◽  
pp. 855-862 ◽  
Author(s):  
Chuang Li ◽  
Haixin Ding ◽  
Zhizhong Ruan ◽  
Yirong Zhou ◽  
Qiang Xiao
Keyword(s):  
Total Synthesis ◽  
Starting Material ◽  
Practical Approach ◽  
High Yield ◽  
Protecting Group ◽  
First Time

In this paper, a practical approach for the total synthesis of kipukasin A is presented with 22% overall yield by using tetra-O-acetyl-β-D-ribose as starting material. An improved iodine-promoted acetonide-forming reaction was developed to access 1,2-O-isopropylidene-α-D-ribofuranose. For the first time, ortho-alkynylbenzoate was used as protecting group for the 5-hydoxy group. After subsequent Vorbrüggen glycosylation, the protecting group could be removed smoothly in the presence of 5 mol % Ph3PAuOTf in dichloromethane to provide kipukasin A in high yield and regioselectivity.

The transformation of levopimaric acid into warburganal

1988 ◽  
Vol 66 (7) ◽  
pp. 1675-1685 ◽  
Author(s):  
William A. Ayer ◽  
Francisco X. Talamas
Keyword(s):  
Double Bond ◽  
Formic Acid ◽  
Sodium Methoxide ◽  
Resin Acid ◽  
Starting Material ◽  
Protecting Group ◽  
Methyl Group ◽  
Levopimaric Acid

The chiral resin acid levopimaric acid (1), isolated from pine oleoresin, is used as a starting material for the synthesis of (−)-warburganal (2). The synthesis proceeds via the endoperoxide of methyl levopimarate, which after ozonolysis, protection of the resulting aldehyde function, reduction, and treatment with sodium methoxide provides the tetranorditerpenoid 12a. The hemiacetal 12a is then transformed to a mixture of hemithioacetals. At this point the carbomethoxyl group at C-4 is reduced to a methyl group, and then a C-11, C-12 double bond is introduced. Ozonolysis followed by elimination of formic acid provides a mixture of olefins (27) that is hydroxylated at C-9. Removal of the protecting group then gives (−)-warburganal (2). The sequence requires 15 steps and the overall yield from levopimaric acid to warburganal is 2.7%.

scholarly journals Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

2017 ◽  
Vol 13 ◽  
pp. 1239-1279 ◽  
Author(s):  
A Michael Downey ◽  
Michal Hocek
Keyword(s):  
Biological Process ◽  
Protecting Groups ◽  
Protecting Group ◽  
Research Groups ◽  
Selective Activation ◽  
Chemical Laboratory ◽  
Differential Reactivity ◽  
Glycosyl Donor ◽  
Anomeric Center

Glycosylation is an immensely important biological process and one that is highly controlled and very efficient in nature. However, in a chemical laboratory the process is much more challenging and usually requires the extensive use of protecting groups to squelch reactivity at undesired reactive moieties. Nonetheless, by taking advantage of the differential reactivity of the anomeric center, a selective activation at this position is possible. As a result, protecting group-free strategies to effect glycosylations are available thanks to the tremendous efforts of many research groups. In this review, we showcase the methods available for the selective activation of the anomeric center on the glycosyl donor and the mechanisms by which the glycosylation reactions take place to illustrate the power these techniques.

scholarly journals Assessment for Melting Temperature Measurement of Nucleic Acid by HRM

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Jing Wang ◽  
Xiaoming Pan ◽  
Xingguo Liang
Keyword(s):  
Thermal Stability ◽  
Nucleic Acid ◽  
Melting Temperature ◽  
High Sensitivity ◽  
Structural Elements ◽  
Sequence Dependence ◽  
Mutation Scanning ◽  
Dna Triplex ◽  
Uv Melting ◽  
Thermal Stability Of

High resolution melting (HRM), with a high sensitivity to distinguish the nucleic acid species with small variations, has been widely applied in the mutation scanning, methylation analysis, and genotyping. For the aim of extending HRM for the evaluation of thermal stability of nucleic acid secondary structures on sequence dependence, we investigated effects of the dye of EvaGreen, metal ions, and impurities (such as dNTPs) on melting temperature (Tm) measurement by HRM. The accuracy of HRM was assessed as compared with UV melting method, and little difference between the two methods was found when the DNA Tm was higher than 40°C. Both insufficiency and excessiveness of EvaGreen were found to give rise to a little bit higher Tm, showing that the proportion of dye should be considered for precise Tm measurement of nucleic acids. Finally, HRM method was also successfully used to measure Tms of DNA triplex, hairpin, and RNA duplex. In conclusion, HRM can be applied in the evaluation of thermal stability of nucleic acid (DNA or RNA) or secondary structural elements (even when dNTPs are present).

Applications of SIMS to electronic materials and devices

1992 ◽  
Vol 50 (2) ◽  
pp. 1682-1683
Author(s):  
S.F. Corcoran
Keyword(s):  
Depth Distribution ◽  
Secondary Ion Mass Spectrometry ◽  
Semiconductor Device ◽  
Electronic Materials ◽  
Profile Analysis ◽  
Semiconductor Industry ◽  
Small Diameter ◽  
Depth Resolution ◽  
Detection Sensitivity

Over the past decade secondary ion mass spectrometry (SIMS) has played an increasingly important role in the characterization of electronic materials and devices. The ability of SIMS to provide part per million detection sensitivity for most elements while maintaining excellent depth resolution has made this technique indispensable in the semiconductor industry. Today SIMS is used extensively in the characterization of dopant profiles, thin film analysis, and trace analysis in bulk materials. The SIMS technique also lends itself to 2-D and 3-D imaging via either the use of stigmatic ion optics or small diameter primary beams.By far the most common application of SIMS is the determination of the depth distribution of dopants (B, As, P) intentionally introduced into semiconductor materials via ion implantation or epitaxial growth. Such measurements are critical since the dopant concentration and depth distribution can seriously affect the performance of a semiconductor device. In a typical depth profile analysis, keV ion sputtering is used to remove successive layers the sample.

Identifying Suicide Typologies Among Trauma-Exposed Veterans

Crisis ◽  
2020 ◽  
Vol 41 (4) ◽  
pp. 288-295 ◽  
Author(s):  
Nadia Bounoua ◽  
Jasmeet P. Hayes ◽  
Naomi Sadeh
Keyword(s):  
Latent Profile Analysis ◽  
Suicide Attempts ◽  
Clinical Symptoms ◽  
Profile Analysis ◽  
Risky Behaviors ◽  
Self Report ◽  
Cross Sectional ◽  
Research Priority ◽  
Self Harm ◽  
And Behaviors

Abstract. Background: Suicide among veterans has increased in recent years, making the identification of those at greatest risk for self-injurious behavior a high research priority. Aims: We investigated whether affective impulsivity and risky behaviors distinguished typologies of self-injurious thoughts and behaviors in a sample of trauma-exposed veterans. Method: A total of 95 trauma-exposed veterans (ages 21–55; 87% men) completed self-report measures of self-injurious thoughts and behaviors, impulsivity, and clinical symptoms. Results: A latent profile analysis produced three classes that differed in suicidal ideation, suicide attempts and nonsuicidal self-injury (NSSI): A low class that reported little to no self-injurious thoughts or behaviors; a self-injurious thoughts (ST) class that endorsed high levels of ideation but no self-harm behaviors; and a self-injurious thoughts and behaviors (STaB) class that reported ideation, suicide attempts and NSSI. Membership in the STaB class was associated with greater affective impulsivity, disinhibition, and distress/arousal than the other two classes. Limitations: Limitations include an overrepresentation of males in our sample, the cross-sectional nature of the data, and reliance on self-report measures. Conclusion: Findings point to affective impulsivity and risky behaviors as important characteristics of veterans who engage in self-injurious behaviors.

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