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1.
J Basic Microbiol ; 61(4): 330-338, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33599337

RESUMEN

Microalgae have received continued attention as a potential source for biofuel production. However, the lack of suitable strains that provide a lipid-rich biomass and tolerate harsh condition inhibits their industrial application. This report describes an effort to transform Synechocystis sp. with genes encoding acetyl-CoA carboxylase (ACC), a key regulatory enzyme in the lipogenesis pathway, from the white mustard plant (Sinapis alba) and the bacterium Escherichia coli DH5α using chitosan nanoparticles. Although a recombinant plasmid encoding S. alba ACC failed to express, successful transformation was achieved with a recombinant plasmid encoding E. coli DH5α ACC. The successful transformant, Synechocystis sp. PAK13, exhibited increased ACC expression compared with its wild-type parent (11.8 vs. 7.2 ng), which significantly increased its lipid content (by 3.6-fold). Synechocystis sp. PAK13 also exhibited a significant (20%) reduction in photosynthetic pigments, a 1.52-fold higher glucose content and a 3.5-fold lower sucrose content than the wild-type. In conclusion, this report introduces a useful strategy to overexpress the ACC gene in microalgae, creating strains with improved lipid production that are suited to industrial applications.

2.
Struct Chem ; : 1-16, 2021 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-33437137

RESUMEN

Recently, the SARS-CoV-2 (COVID-19) pandemic virus has been spreading throughout the world. Until now, no certified drugs have been discovered to efficiently inhibit the virus. The scientists are struggling to find new safe bioactive inhibitors of this deadly virus. In this study, we aim to find antagonists that may inhibit the activity of the three major viral targets: SARS-CoV-2 3-chymotrypsin-like protease (6LU7), SARS-CoV-2 spike protein (6VYB), and a host target human angiotensin-converting enzyme 2 (ACE2) receptor (1R42), which is the entry point for the viral encounter, were studied with the prospects of identifying significant drug candidate(s) against COVID-19 infection. Then, the protein stability produced score of less than 0.6 for all residues of all studied receptors. This confirmed that these receptors are extremely stable proteins, so it is very difficult to unstable the stability of these proteins through utilizing individual drugs. Hence, we studied the combination and tricombination therapy between bioactive compounds which have the best binding affinity and some antiviral drugs like chloroquine, hydroxychloroquine, azithromycin, simeprevir, baloxavir, lopinavir, and favipiravir to show the effect of combination and tricombination therapy to disrupt the stability of the three major viral targets that are mentioned previously. Also, ADMET study suggested that most of all studied bioactive compounds are safe and nontoxic compounds. All results confirmed that caulerpin can be utilized as a combination and tricombination therapy along with the studied antiviral drugs for disrupting the stability of the three major viral receptors (6LU7, 6VYB, and 1R42). Supplementary Information: The online version contains supplementary material available at 10.1007/s11224-020-01723-5.

3.
Artículo en Inglés | MEDLINE | ID: mdl-32998618

RESUMEN

This work aimed at evaluating the inhibitory effect of ten natural bioactive compounds (1-10) as potential inhibitors of SARS-CoV-2-3CL main protease (PDB ID: 6LU7) and SARS-CoV main proteases (PDB IDs: 2GTB and 3TNT) by molecular docking analysis. The inhibitory effect of all studied compounds was studied with compared to some proposed antiviral drugs which currently used in COVID-19 treatment such as chloroquine, hydroxychloroquine, azithromycin, remdesivir, baloxvir, lopinavir, and favipiravir. Homology modeling and sequence alignment was computed to evaluate the similarity between the SARS-CoV-2-3CL main protease and other SARS-CoV receptors. ADMET properties of all studied compounds were computed and reported. Also, molecular dynamic (MD) simulation was performed on the compound which has the highest binding affinity inside 6LU7 obtained from molecular docking analysis to study it is stability inside receptor in explicit water solvent. Based on molecular docking analysis, we found that caulerpin has the highest binding affinity inside all studied receptors compared to other bioactive compounds and studied drugs. Our homology modeling and sequence alignment showed that SARS-CoV main protease (PDB ID: 3TNT) shares high similarity with 3CLpro (96.00%). Also, ADMET properties confirmed that caulerpin obeys Lipinski's rule and passes ADMET property, which make it a promising compound to act as a new safe natural drug against SARS-CoV-2-3CL main protease. Finally, MD simulation confirmed that the complex formed between caulerpin and 3CLpro is stable in water explicit and had no major effect on the flexibility of the protein throughout the simulations and provided a suitable basis for our study. Also, binding free energy between caulerpin and 6LU7 confirmed the efficacy of the caulerpin molecule against SARS-CoV-2 main protease. So, this study suggested that caulerpin could be used as a potential candidate in COVID-19 treatment.


Asunto(s)
Betacoronavirus/efectos de los fármacos , Betacoronavirus/enzimología , Cisteína Endopeptidasas/metabolismo , Indoles/farmacología , Proteínas no Estructurales Virales/metabolismo , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular
4.
Struct Chem ; : 1-22, 2020 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-32837118

RESUMEN

Presently, the SARS-CoV-2 (COVID-19) pandemic has been spreading throughout the world. Some drugs such as lopinavir, simeprevir, hydroxychloroquine, chloroquine, and amprenavir have been recommended for COVID-19 treatment by some researchers, but these drugs were not effective enough against this virus. This study based on in silico approaches was aimed to increase the anti-COVID-19 activities of these drugs by using caulerpin and its derivatives as an adjunct drug against SARS-CoV-2 receptor proteins: the SARS-CoV-2 main protease and the SARS-CoV-2 spike protein. Caulerpin exhibited antiviral activities against chikungunya virus and herpes simplex virus type 1. Caulerpin and some of its derivatives showed inhibitory activity against Alzheimer's disease. The web server ANCHOR revealed higher protein stability for the two receptors with disordered score (< 0.6). Molecular docking analysis showed that the binding energies of most of the caulerpin derivatives were higher than all the suggested drugs for the two receptors. Also, we deduced that inserting NH2, halogen, and vinyl groups can increase the binding affinity of caulerpin toward 6VYB and 6LU7, while inserting an alkyl group decreases the binding affinity of caulerpin toward 6VYB and 6LU7. So, we can modify the inhibitory effect of caulerpin against 6VYB and 6LU7 by inserting NH2, halogen, and vinyl groups. Based on the protein disordered results, the SARS-CoV-2 main protease and SARS-CoV-2 spike protein domain are highly stable proteins, so it is quite difficult to unstabilize their integrity by using individual drugs. Also, molecular dynamics (MD) simulation indicates that binding of the combination therapy of simeprevir and the candidate studied compounds to the receptors was stable and had no major effect on the flexibility of the protein throughout the simulations and provided a suitable basis for our study. So, this study suggested that caulerpin and its derivatives could be used as a combination therapy along with lopinavir, simeprevir, hydroxychloroquine, chloroquine, and amprenavir for disrupting the stability of SARS-CoV2 receptor proteins to increase the antiviral activity of these drugs.

5.
J Biomol Struct Dyn ; : 1-11, 2020 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-32579063

RESUMEN

Caulerpin, a bis-indole alkaloid is isolated from a new source Sargassum platycarpum, brown alga (family Sargassaceae) for the first time. The structure of caulerpin was characterized by IR, H1NMR, C13 NMR, HSQC, HMBC, EI-MS spectroscopy. Antifungal results suggest that caulerpin has been inhibited Cryptococcus neoformas (12 mm) and Candida albicans (7 mm) than other microbes. In vitro anticancer activity of caulerpin has been explored by cell viability assay against new human cancer cell line (liver-HepG2). The results show that caulerpin has low IC50 value (24.6 ± 2.1 µg/mL) against HepG-2. Based on the least toxic activity of caulerpin, these results encourage for future in vivo anticancer study. The binding of caulerpin molecule with the two nucleobases (T/U) bases has been studied by DFT methods. According to the AIM analysis, there are two types of interactions between caulerpin and T/U bases partially covalent partially electrostatic and electrostatic in gas and water phases. Based on NBO analysis, the charges were transferred from the lone-pair (n) in orbitals of O atoms of caulerpin to the σ* orbitals of T/U bases atoms. ΔEbin in the state of caulerpin-T bases complexes are lower than those in the caulerpin-U bases complexes in both gas and water phase. MD simulation supported that caulerpin-T/U bases complexes are stable in presence of explicit water phase. Thus, the findings of our study will be useful for giving an insight into the caulerpin/bases complexes that could be helpful in future experimental studies to develop the performance of caulerpin molecules as natural candidate drug. Communicated by Ramaswamy H. Sarma.

6.
J Biomol Struct Dyn ; : 1-19, 2020 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-32462976

RESUMEN

In this study, nine compounds were isolated, eight of them were isolated for the first time from Cystoseira trinodis. The biological activity of the extract, fractions and pure compounds was evaluated. The antimicrobial activity was investigated against 3 fungi species, 3 gram + ve and 3 gram -ve bacteria. The crude extract and fractions showed moderate inhibition against some of the tested microorganisms, especially the butanol fraction exhibited the maximum inhibition zone against Salmonella typhimurium (16 ± 0.60 mm). Cytotoxicity was evaluated against HepG-2 and MCF-7 cell lines. Hexane fraction exhibited the highest cytotoxic effect against HepG-2 and MCF-7 cell lines with an IC50 value of 14.3 ± 0.8 and 19.2 ± 0.7 µg/ml, respectively with compared to other fractions. The isolates were identified as octacosanoic acid (1), glyceryl trilinoleate (2), oleic acid (3), and the epimeric mixture of saringosterols (4, 5), ß-sitosterol (6), glycoglycerolipid (7) and a mixture of kjellmanianone and loliolide (8, 9) by spectroscopic analysis. Among the all tested compounds kjellmanianone and loliolide mixture exhibited significant cytotoxic activity with an IC50 value of 7.27 µg/ml against HepG-2 cells. The major and minor constituents of the extract and fractions were identified using GC-MS analysis. Molecular docking analysis confirmed that most of the studied compounds especially compounds 8 and 9 strongly interact with TPK and VEGFR-2 with highest binding energies supported that the high cytotoxicity of these compounds against human hepatocellular cancer in the experimental part. The energetic, geometric and topological properties of compounds 8 and 9 binding with cytosine base were computed by DFT methods. Molecular properties descriptors, bioactivity score and ADMET analysis confirmed that most of the studied compounds especially compounds 8 and 9 exhibit significant biological activities and have a better chance to be developed as drug leads. Communicated by Ramaswamy H. Sarma.

7.
J Phys Chem Lett ; 11(5): 1934-1939, 2020 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-32067463

RESUMEN

Slow polypeptide conformational changes on time scales of >1 s are generally assumed to be highly cooperative two-state transitions, reflecting the high energy barrier. However, few experimental characterizations have tested the validity of this assumption. We performed residue-specific NMR thermodynamic analysis of the 27-residue lantibiotic peptide, nukacin ISK-1, to characterize the isomerization between two topological states on the second time scale. Unexpectedly, the thermal transition behaviors were distinct among peptide regions, indicating that the topological isomerization process is a mosaic of different degrees of cooperativity. The conformational change path between the two NMR structures was deduced by a targeted molecular dynamics simulation. The unique side-chain threading motions through the monosulfide rings are the structural basis of the high energy barrier, and the nonlocal interactions in the hydrophobic core are the structural basis of the cooperativity. Taken together, we provide an energetic description of the topological isomerization of nukacin ISK-1.


Asunto(s)
Bacteriocinas/química , Resonancia Magnética Nuclear Biomolecular , Bacteriocinas/metabolismo , Dicroismo Circular , Isomerismo , Simulación de Dinámica Molecular , Staphylococcus/metabolismo , Termodinámica
8.
Commun Biol ; 1: 150, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30272026

RESUMEN

The lantibiotic nukacin ISK-1 exerts antimicrobial activity through binding to lipid II. Here, we perform NMR analyses of the structure of nukacin ISK-1 and the interaction with lipid II. Unexpectedly, nukacin ISK-1 exists in two structural states in aqueous solution, with an interconversion rate on a time scale of seconds. The two structures differ in the relative orientations of the two lanthionine rings, ring A and ring C. Chemical shift perturbation induced by the titration of lipid II reveals that only one state was capable of binding to lipid II. On the molecular surface of the active state, a multiple hydrogen-bonding site formed by amino acid residues in the ring A region is adjacent to a hydrophobic surface formed by residues in the ring C region, and we propose that these sites interact with the pyrophosphate moiety and the isoprene chain of the lipid II molecule, respectively.

9.
Spectrochim Acta A Mol Biomol Spectrosc ; 193: 518-522, 2018 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-29304486

RESUMEN

Casting solution method has been used to prepare Polyvinyl alcohol (PVA) film. The prepared film has been irradiated with a laser beam of 6ns Q-switched Nd:YAG laser (Lotus II) operating at 10Hz and fourth harmonic wavelength, 266nm, at different irradiation times. Optical absorbance of the irradiated sample was studied in the wavelength region between 200 and 800nm. The absorption peak shift of 272nm towards the longer wavelengths region and the increase of absorption as the irradiation time increases, are related to the increase in crosslinking network. The fitting technique of the absorbance revealed an indirect allowed transition with optical energy gap of 4.22eV for the pristine PVA sample, and 2.85eV after 2h of laser irradiation. The index of refraction and the dielectric function showed dispersion in the studied wavelength range. The analysis of color parameters of PVA showed an observable change after laser irradiation.

10.
3 Biotech ; 7(1): 41, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28439814

RESUMEN

Over the last few decades, many scientists considered microalgae as promising actors for future biofuels because of the high lipid productivity inside their cells. Moreover, much attention has been paid to algal lipids as they can be used in biodiesel production. In this study, we optimized the different suitable conditions such as incubation time, incubation temperature, Dimethylesulfoxide and Nile red concentrations of the lipophilic fluorescence dye Nile red as an excellent and fast vital stain to detect and quantify intracellular lipids. This was achieved using the green alga Nannochloropsis salina. In addition, investigating the accumulation of lipid vesicles inside different isolated microalgal species as a response to temperature stress. Furthermore, the confocal laser scanning microscopy (LS510) for imaging and measuring the size and volume of the accumulated lipid vesicles was used.

11.
J Biosci Bioeng ; 123(3): 398-401, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27856233

RESUMEN

Binding to lipid II is an important step in the mode of action of most lantibiotics targeting the bacterial cell wall. We applied the Bacillus subtilis two-component system, LiaRS, that is known to respond to antibiotics interfering with lipid II cycle, in order to evaluate lipid II binding activity of known bacteriocins and also to identify lipid II binding moieties in lantibiotic nukacin ISK-1. Using this method, we confirmed that the methyllanthionine ring in nukacin ISK-1 is crucial for lipid II binding as previously indicated. In this study, we further identified that the three N-terminal lysine residues (K1, K2, and K3) and the glycine (G5) residue in nukacin ISK-1 are also important in lipid II binding.


Asunto(s)
Bacillus subtilis/metabolismo , Bacteriocinas/química , Bacteriocinas/metabolismo , Genes Reporteros , Uridina Difosfato Ácido N-Acetilmurámico/análogos & derivados , Alanina/análogos & derivados , Alanina/metabolismo , Secuencia de Aminoácidos , Pared Celular/metabolismo , Sulfuros/metabolismo , Uridina Difosfato Ácido N-Acetilmurámico/metabolismo
12.
Nat Prod Commun ; 7(9): 1209-10, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23074910

RESUMEN

Extracts of four species of seaweeds, Ulva lactuca L. (green), Liagora farinosa Lamouroux (red), Padina pavonia L. and Turbinaria ornata Turn (brown), were screened for their antimicrobial, and antimalarial activities, and binding affinity for human opioid receptors. Phytochemical analysis led to the isolation and identification of 10 constituents: fucosterol, stearic acid, palmitic acid, palmitoleic acid, oleic acid, myristic acid, p-hydroxybenzoic acid, beta-sitosterol, glycerol-1-olyl-3-palmotyl-2-galactoside, and glycerol-1,3-diolyl, The last two compounds displayed strong binding affinity to delta opioid receptors.


Asunto(s)
Algas Marinas/química , Egipto , Humanos
13.
Appl Opt ; 42(33): 6650-60, 2003 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-14658468

RESUMEN

An all solid-state Ti:sapphire laser differential absorption lidar transmitter was developed. This all-solid-state laser provides a compact, robust, and highly reliable laser transmitter for potential application in differential absorption lidar measurements of atmospheric ozone. Two compact, high-energy-pulsed, and injection-seeded Ti:sapphire lasers operating at a pulse repetition frequency of 30 Hz and wavelengths of 867 and 900 nm, with M2 of 1.3, have been experimentally demonstrated and their properties compared with model results. The output pulse energy was 115 mJ at 867 nm and 105 mJ at 900 nm, with a slope efficiency of 40% and 32%, respectively. At these energies, the beam quality was good enough so that we were able to achieve 30 mJ of ultraviolet laser output at 289 and 300 nm after frequency tripling with two lithium triborate nonlinear crystals.

14.
Appl Opt ; 41(15): 2734-9, 2002 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-12027160

RESUMEN

Two compact, high-pulse-energy, injection-seeded, 30-Hz frequency-doubled Nd:YAG-laser-pumped Ti: sapphire lasers were developed and operated at infrared wavelengths of 867 and 900 nm. Beams with laser pulse energy >30 mJ at ultraviolet wavelengths of 289 and 300 nm were generated through a tripling of the frequencies of these Ti:sapphire lasers. This work is directed at the replacement of dye lasers for use in an airborne ozone differential absorption lidar system. The ultraviolet pulse energy at 289 and 300 nm had 27% and 31% absolute optical energy conversion efficiencies from input pulse energies at 867 and 900 nm, respectively.

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