scholarly journals Depsidone Derivatives and a Cyclopeptide Produced by Marine Fungus Aspergillus unguis under Chemical Induction and by Its Plasma Induced Mutant

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2245 ◽  
Author(s):  
Wen-Cong Yang ◽  
Hai-Yan Bao ◽  
Ya-Yue Liu ◽  
Ying-Ying Nie ◽  
Jing-Ming Yang ◽  
...  
Keyword(s):  
Cyclic Peptide ◽  
Docking Studies ◽  
Marine Fungus ◽  
Strong Interactions ◽  
Original Strain ◽  
Chemical Induction ◽  
Strong Activity ◽  
Hplc Fingerprint ◽  
Aspergillus Unguis ◽  
Induced Mutant

A new depsidone derivative (1), aspergillusidone G, was isolated from a marine fungus Aspergillus unguis, together with eight known depsidones (2‒9) and a cyclic peptide (10): agonodepside A (2), nornidulin (3), nidulin (4), aspergillusidone F (5), unguinol (6), aspergillusidone C (7), 2-chlorounguinol (8), aspergillusidone A (9), and unguisin A (10). Compounds 1‒4 and 7‒9 were obtained from the plasma induced mutant of this fungus, while 5, 6, and 10 were isolated from the original strain under chemical induction. Their structures were identified using spectroscopic analysis, as well as by comparison with literature data. The HPLC fingerprint analysis indicates that chemical induction and plasma mutagenesis effectively influenced the secondary metabolism, which may be due to their regulation in the key steps in depsidone biosynthesis. In bioassays, compound 9 inhibited acetylcholinesterase (AChE) with IC50 in 56.75 μM. Compounds 1, 5, 7, 8, and 9 showed moderate to strong activity towards different microbes. Compounds 3, 4, and 5 exhibited potent larvicidality against brine shrimp. In docking studies, higher negative CDOCKER interaction energy and richer strong interactions between AChE and 9 explained the greater activity of 9 compared to 1. Chemical induction and plasma mutagenesis can be used as tools to expand the chemodiversity of fungi and obtain useful natural products.

scholarly journals Synthesis and Biological Activity of Triazole Derivatives of Osajin

2021 ◽  
Vol 33 (6) ◽  
pp. 1267-1272
Author(s):  
L.V. Ramana ◽  
K.M.Ch. Appa Rao ◽  
M. Suri Appa Rao ◽  
Ch. Venkata ramanaiah ◽  
G. Nageswara Rao
Keyword(s):  
Molecular Docking ◽  
Cell Lines ◽  
Parent Compound ◽  
Docking Studies ◽  
Strong Interactions ◽  
Spectroscopic Techniques ◽  
Docking Analysis ◽  
Hela Cell Lines ◽  
In Silico Molecular Docking ◽  
Derivatives Of

In the present study, osajin-1,2,3-triazole hybrids were designed, synthesized and evaluated for their anti-proliferative activity against MCF-7, PC-3 and Hela cell lines. Many of the synthesized hybrid derivatives were found potent than the parent compound, osajin (1). All the semi-synthesized derivatives (3a-j) were characterized by using mass and NMR spectroscopic techniques. Among the newly synthesized compounds, 3c, 3d, and 3e were shown promising activities against the tested cell lines compared with doxorubicin standard. In addition, molecular docking studies of the synthesized compounds have shown a good correlation with in silico molecular docking analysis by exhibiting strong interactions with the inhibitor HERA-protein.

scholarly journals Targeting novel coronavirus SARS-CoV-2 spike protein with phytoconstituents of Momordica charantia

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Santosh Kumar Singh ◽  
Shailesh Singh ◽  
Rajesh Singh
Keyword(s):  
Viral Infections ◽  
Hydrophobic Interactions ◽  
Docking Study ◽  
Docking Studies ◽  
Momordica Charantia ◽  
Spike Protein ◽  
Strong Interactions ◽  
Bitter Melon ◽  
Novel Coronavirus ◽  
Potential Interactions

Abstract Background Infections by the SARS-CoV-2 virus causing COVID-19 are presently a global emergency. The current vaccination effort may reduce the infection rate, but strain variants are emerging under selection pressure. Thus, there is an urgent need to find drugs that treat COVID-19 and save human lives. Hence, in this study, we identified phytoconstituents of an edible vegetable, Bitter melon (Momordica charantia), that affect the SARS-CoV-2 spike protein. Methods Components of Momordica charantia were tested to identify the compounds that bind to the SARS-CoV-2 spike protein. An MTiOpenScreen web-server was used to perform docking studies. The Lipinski rule was utilized to evaluate potential interactions between the drug and other target molecules. PyMol and Schrodinger software were used to identify the hydrophilic and hydrophobic interactions. Surface plasmon resonance (SPR) was employed to assess the interaction between an extract component (erythrodiol) and the spike protein. Results Our in-silico evaluations showed that phytoconstituents of Momordica charantia have a low binding energy range, -5.82 to -5.97 kcal/mol. A docking study revealed two sets of phytoconstituents that bind at the S1 and S2 domains of SARS-CoV-2. SPR showed that erythrodiol has a strong binding affinity (KD = 1.15 μM) with the S2 spike protein of SARS-CoV-2. Overall, docking, ADME properties, and SPR displayed strong interactions between phytoconstituents and the active site of the SARS-CoV-2 spike protein. Conclusion This study reveals that phytoconstituents from bitter melon are potential agents to treat SARS-CoV-2 viral infections due to their binding to spike proteins S1 and S2.

scholarly journals N-ferrocenylmethyl-Derivatives As Spike Glycoprotein Inhibitors Of SARS-CoV-2 Using In Silico Approaches

2020 ◽  
Author(s):  
NADJIBA ZEGHEB ◽  
LANEZ Elhafnaoui ◽  
Touhami Lanez
Keyword(s):  
Data Bank ◽  
Cell Receptor ◽  
Docking Studies ◽  
Strong Interactions ◽  
Spike Glycoprotein ◽  
Ferrocene Derivatives ◽  
Angiotensin Converting Enzyme 2 ◽  
Host Cell Receptor ◽  
Global Pandemic ◽  
Glycoprotein Inhibitors

<p><b>Background and Objectives:</b> By the end of 2019, a novel human coronavirus outbreak started in Wuhan and spread to the world becoming a global pandemic, patients were diagnosed with severe respiratory syndrome. Studies have shown that SARS-CoV2 interact with angiotensin-converting enzyme 2 (ACE2), its host cell receptor, by its Spike Glycoprotein. The aim of this study is to prevent this interaction by inhibiting Spike glycoprotein.<b> Materials and Methods:</b> The interaction of the Spike Glycoprotein of SARS-COV-2 extracted from protein data bank (PDB Code: 6VSB and 6LZG) with 10 different ferrocene derivatives ligands were investigated by performing docking studies using Autodock Tools 4.2. software. <b>Results:</b> The obtained results showed that N-ferrocenyl-methyl-3-nitroaniline was the best inhibitor ligand interacted with both proteins of coronavirus with the free binding energy equal to -5.38 and -6.65 Kcal/mol for 6VSB and 6LZG respectively with binding constant values equal to 8.7 × 10<sup>3</sup> and 72.72× 10<sup>3</sup>respectively. Calculations revealed that the dominated mode of interaction for all the studied ligands with COVID-19 was the electrostatic mode via at least one H-bond and more than two hydrophobic Pi-Alkyl Bonds. <b>Conclusion: </b>Generally, the results indicated the existence of strong interactions between ligands and spike glycoprotein which prevent the virus to interact to ACE2 receptors.</p>

scholarly journals Synthesis and Evaluation of the 4-Substituted 2-Hydroxy-5-Iodochalcones and Their 7-Substituted 6-Iodoflavonol Derivatives for Inhibitory Effect on Cholinesterases and β-Secretase

2018 ◽  
Vol 19 (12) ◽  
pp. 4112 ◽  
Author(s):  
Malose Mphahlele ◽  
Emmanuel Agbo ◽  
Samantha Gildenhuys
Keyword(s):  
Kinetic Studies ◽  
Inhibitory Effect ◽  
Docking Studies ◽  
Significant Inhibition ◽  
Strong Interactions ◽  
Protein Residues ◽  
Significant Inhibitory Effect ◽  
Increased Activity ◽  
Bace 1

A series of 2-aryl-3-hydroxy-6-iodo-4H-chromen-4-ones substituted at the 7-position with a halogen atom (X = F, Cl and Br) or methoxy group and their corresponding 4-substituted 2-hydroxy-5-iodochalcone precursors were evaluated in vitro for inhibitory effect against acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and β-secretase (BACE1) activities. Although moderate inhibitory effect was observed for the chalcones against AChE, derivatives 2h, 2j and 2n exhibited significant inhibitory effect against BChE and BACE-1. The 2-aryl-7-fluoro-8-iodoflavonols 3b and 3c, on the other hand, exhibited increased activity and selectivity against AChE and reduced effect on BACE-1. The flavonols 3h, 3i, 3k, 3l and 3p exhibited moderate inhibitory effect against AChE, but significant inhibition against BChE. Compounds 2j and 3l exhibited non-competitive mode of inhibition against BACE-1. Molecular docking predicted strong interactions with the protein residues in the active site of BACE-1 implying these compounds bind with the substrate. Similarly docking studies predicted interaction of the most active compounds with both CAS and PAS of either AChE or BChE with mixed type of enzyme inhibition confirmed by kinetic studies.

scholarly journals N-ferrocenylmethyl-Derivatives As Spike Glycoprotein Inhibitors Of SARS-CoV-2 Using In Silico Approaches

2020 ◽  
Author(s):  
NADJIBA ZEGHEB ◽  
LANEZ Elhafnaoui ◽  
Touhami Lanez
Keyword(s):  
Data Bank ◽  
Cell Receptor ◽  
Docking Studies ◽  
Strong Interactions ◽  
Spike Glycoprotein ◽  
Ferrocene Derivatives ◽  
Angiotensin Converting Enzyme 2 ◽  
Host Cell Receptor ◽  
Global Pandemic ◽  
Glycoprotein Inhibitors

<p><b>Background and Objectives:</b> By the end of 2019, a novel human coronavirus outbreak started in Wuhan and spread to the world becoming a global pandemic, patients were diagnosed with severe respiratory syndrome. Studies have shown that SARS-CoV2 interact with angiotensin-converting enzyme 2 (ACE2), its host cell receptor, by its Spike Glycoprotein. The aim of this study is to prevent this interaction by inhibiting Spike glycoprotein.<b> Materials and Methods:</b> The interaction of the Spike Glycoprotein of SARS-COV-2 extracted from protein data bank (PDB Code: 6VSB and 6LZG) with 10 different ferrocene derivatives ligands were investigated by performing docking studies using Autodock Tools 4.2. software. <b>Results:</b> The obtained results showed that N-ferrocenyl-methyl-3-nitroaniline was the best inhibitor ligand interacted with both proteins of coronavirus with the free binding energy equal to -5.38 and -6.65 Kcal/mol for 6VSB and 6LZG respectively with binding constant values equal to 8.7 × 10<sup>3</sup> and 72.72× 10<sup>3</sup>respectively. Calculations revealed that the dominated mode of interaction for all the studied ligands with COVID-19 was the electrostatic mode via at least one H-bond and more than two hydrophobic Pi-Alkyl Bonds. <b>Conclusion: </b>Generally, the results indicated the existence of strong interactions between ligands and spike glycoprotein which prevent the virus to interact to ACE2 receptors.</p>

200kv superconducting cryo electron microscope

1987 ◽  
Vol 45 ◽  
pp. 642-643
Author(s):  
M. Iwatsuki ◽  
Y. Kokubo ◽  
Y. Harada ◽  
J. Lehman
Keyword(s):  
Electron Microscope ◽  
Structure Analysis ◽  
Organic Materials ◽  
Strong Interactions ◽  
Specimen Preparation ◽  
Great Effort ◽  
Electron Microscopic ◽  
Crystal Fields ◽  
Special Skill ◽  
Long Time

In recent years, the electron microscope has been significantly improved in resolution and we can obtain routinely atomic-level high resolution images without any special skill. With this improvement, the structure analysis of organic materials has become one of the interesting targets in the biological and polymer crystal fields.Up to now, X-ray structure analysis has been mainly used for such materials. With this method, however, great effort and a long time are required for specimen preparation because of the need for larger crystals. This method can analyze average crystal structure but is insufficient for interpreting it on the atomic or molecular level. The electron microscopic method for organic materials has not only the advantage of specimen preparation but also the capability of providing various information from extremely small specimen regions, using strong interactions between electrons and the substance. On the other hand, however, this strong interaction has a big disadvantage in high radiation damage.

New form of Transmission Cross Coefficient for High-Resolution Imaging

1990 ◽  
Vol 48 (1) ◽  
pp. 60-61
Author(s):  
Kazuo Ishizuka
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Function ◽  
Incident Beam ◽  
Optical Microscope ◽  
Strong Interactions ◽  
Small Range ◽  
Specimen Thickness ◽  
Beam Direction ◽  
Diffracted Waves

It is well known that taking into account spacial and temporal coherency of illumination as well as the wave aberration is important to interpret an image of a high-resolution electron microscope (HREM). This occues, because coherency of incident electrons restricts transmission of image information. Due to its large spherical and chromatic aberrations, the electron microscope requires higher coherency than the optical microscope. On an application of HREM for a strong scattering object, we have to estimate the contribution of the interference between the diffracted waves on an image formation. The contribution of each pair of diffracted waves may be properly represented by the transmission cross coefficients (TCC) between these waves. In this report, we will show an improved form of the TCC including second order derivatives, and compare it with the first order TCC.In the electron microscope the specimen is illuminated by quasi monochromatic electrons having a small range of illumination directions. Thus, the image intensity for each energy and each incident direction should be summed to give an intensity to be observed. However, this is a time consuming process, if the ranges of incident energy and/or illumination direction are large. To avoid this difficulty, we can use the TCC by assuming that a transmission function of the specimen does not depend on the incident beam direction. This is not always true, because dynamical scattering is important owing to strong interactions of electrons with the specimen. However, in the case of HREM, both the specimen thickness and the illumination angle should be small. Therefore we may neglect the dependency of the transmission function on the incident beam direction.

Sign in / Sign up

Export Citation Format

Share Document