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Marine Drugs ◽  
2022 ◽  
Vol 20 (1) ◽  
pp. 58
Author(s):  
José X. Soares ◽  
Daniela R. P. Loureiro ◽  
Ana Laura Dias ◽  
Salete Reis ◽  
Madalena M. M. Pinto ◽  
...  

The marine environment is an important source of specialized metabolites with valuable biological activities. Xanthones are a relevant chemical class of specialized metabolites found in this environment due to their structural variety and their biological activities. In this work, a comprehensive literature review of marine xanthones reported up to now was performed. A large number of bioactive xanthone derivatives (169) were identified, and their structures, biological activities, and natural sources were described. To characterize the chemical space occupied by marine-derived xanthones, molecular descriptors were calculated. For the analysis of the molecular descriptors, the xanthone derivatives were grouped into five structural categories (simple, prenylated, O-heterocyclic, complex, and hydroxanthones) and six biological activities (antitumor, antibacterial, antidiabetic, antifungal, antiviral, and miscellaneous). Moreover, the natural product-likeness and the drug-likeness of marine xanthones were also assessed. Marine xanthone derivatives are rewarding bioactive compounds and constitute a promising starting point for the design of other novel bioactive molecules.


Toxins ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 4
Author(s):  
Sevasti-Kiriaki Zervou ◽  
Triantafyllos Kaloudis ◽  
Spyros Gkelis ◽  
Anastasia Hiskia ◽  
Hanna Mazur-Marzec

Cyanobacteria are photosynthetic microorganisms that are able to produce a large number of secondary metabolites. In freshwaters, under favorable conditions, they can rapidly multiply, forming blooms, and can release their toxic/bioactive metabolites in water. Among them, anabaenopeptins (APs) are a less studied class of cyclic bioactive cyanopeptides. The occurrence and structural variety of APs in cyanobacterial blooms and cultured strains from Greek freshwaters were investigated. Cyanobacterial extracts were analyzed with LC–qTRAP MS/MS using information-dependent acquisition in enhanced ion product mode in order to obtain the fragmentation mass spectra of APs. Thirteen APs were detected, and their possible structures were annotated based on the elucidation of fragmentation spectra, including three novel ones. APs were present in the majority of bloom samples (91%) collected from nine Greek lakes during different time periods. A large variety of APs was observed, with up to eight congeners co-occurring in the same sample. AP F (87%), Oscillamide Y (87%) and AP B (65%) were the most frequently detected congeners. Thirty cyanobacterial strain cultures were also analyzed. APs were only detected in one strain (Microcystis ichtyoblabe). The results contribute to a better understanding of APs produced by freshwater cyanobacteria and expand the range of structurally characterized APs.


Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2393
Author(s):  
Sandrien Desmet ◽  
Kris Morreel ◽  
Rebecca Dauwe

The plant specialized metabolome consists of a multitude of structurally and functionally diverse metabolites, variable from species to species. The specialized metabolites play roles in the response to environmental changes and abiotic or biotic stresses, as well as in plant growth and development. At its basis, the specialized metabolism is built of four major pathways, each starting from a few distinct primary metabolism precursors, and leading to distinct basic carbon skeleton core structures: polyketides and fatty acid derivatives, terpenoids, alkaloids, and phenolics. Structural diversity in specialized metabolism, however, expands exponentially with each subsequent modification. We review here the major sources of structural variety and question if a specific role can be attributed to each distinct structure. We focus on the influences that various core structures and modifications have on flavonoid antioxidant activity and on the diversity generated by oxidative coupling reactions. We suggest that many oxidative coupling products, triggered by initial radical scavenging, may not have a function in se, but could potentially be enzymatically recycled to effective antioxidants. We further discuss the wide structural variety created by multiple decorations (glycosylations, acylations, prenylations), the formation of high-molecular weight conjugates and polyesters, and the plasticity of the specialized metabolism. We draw attention to the need for untargeted methods to identify the complex, multiply decorated and conjugated compounds, in order to study the functioning of the plant specialized metabolome.


Synthesis ◽  
2021 ◽  
Author(s):  
Yurii V. Ostapiuk ◽  
Andreas Schmidt ◽  
Maksym Shehedyn ◽  
Oksana V. Barabash ◽  
Bohdan Demydchuk ◽  
...  

AbstractMethyl 3-aryl-2-bromo-2-chloropropanoates can be prepared by Meerwein reaction from methyl 2-chloroacrylate and various arenediazonium salts under copper(II) bromide catalysis. The resulting readily available compounds were used as starting materials in reactions with substituted methanethiols for the construction of substituted 3-hydroxythiophenes which have not yet been accessible by other routes. Structural variety of the obtained 2-substituted 5-aryl-3-hydroxythiophenes has been achieved due to a wide range of available starting materials, including both anilines and thiols.


Synthesis ◽  
2021 ◽  
Author(s):  
alexandre guy ◽  
Jérémy Merad ◽  
Thomas Degrange ◽  
Guillaume Reversat ◽  
Valérie Bultel-Poncé ◽  
...  

Oxylipins are formed in-vivo from polyunsaturated fatty acids (PUFAs). A large structural variety of compounds is grouped under the term oxylipins, which differ from their formation mechanism (involving enzymes or not), as well as their chemical structures (cyclopentanes, tetrahydrofurans, hydroxylated-PUFA etc.). All structures of oxylipins are of great biological interests. Directly correlated to oxidative stress phenomenon, non-enzymatic oxylipins are used as systemic and/or specific biomarkers in various pathologies and more especially, they were found to have their own biological properties. Produced in-vivo as a non-separable mixture of isomers, total synthesis is a keystone to answer biological questions. In this work, we described the total synthesis of three non-enzymatic oxylipins derived from docosahexaenoic acid (DHA) and docosapentanoic acid (DPAn-3) using a unique and convergent synthetic strategy.


2021 ◽  
Vol 70 (9) ◽  
pp. 1699-1705
Author(s):  
O. P. Ivanova ◽  
A. V. Krivandin ◽  
S. A. Zav’yalov ◽  
T. S. Zhuravleva

2021 ◽  
Vol 11 (17) ◽  
pp. 8018
Author(s):  
Chengshang Chen ◽  
Yuhan Fang ◽  
Chichen Jang ◽  
Wenchi Chen ◽  
Hui-Chi Lin ◽  
...  

We theoretically demonstrate that a family of vortex-lattice structures can be flexibly generated using a multi-beam interference approach. Numerical calculation presents a variety of crystalline and kaleidoscopic patterns. Based on the numerical analysis, we experimentally realized these structure beams by combining an amplitude mask with multiple apertures and a spiral phase plate. The excellent agreement between the experimental and theoretical results not only validates the presented method, but also manifests the structure of vortex lattices.


Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1158
Author(s):  
Dobrochna Adamek-Urbańska ◽  
Ewelina Błażewicz ◽  
Magdalena Sobień ◽  
Robert Kasprzak ◽  
Maciej Kamaszewski

Accessory respiratory organs (AROs) are a group of anatomical structures found in fish, which support the gills and skin in the process of oxygen uptake. AROs are found in many fish taxa and differ significantly, but in the suborder Anabantoidei, which has a labyrinth organ (LO), and the family Clariidae, which has a dendritic organ (DO), these structures are found in the suprabranchial cavity (SBC). In this study, the SBC walls, AROs, and gills were studied in anabantoid (Betta splendens, Ctenopoma acutirostre, Helostoma temminckii) and clariid (Clarias angolensis, Clarias batrachus) fishes. The histological structure of the investigated organs was partially similar, especially in relation to their connective tissue core; however, there were noticeable differences in the epithelial layer. There were no significant species-specific differences in the structure of the AROs within the two taxa, but the SBC walls had diversified structures, depending on the observed location. The observed differences between species suggest that the remarkable physiological and morphological plasticity of the five investigated species can be associated with structural variety within their AROs. Furthermore, based on the observed histology of the SBC walls, it is reasonable to conclude that this structure participates in the process of gas exchange, not only in clariid fish but also in anabantoids.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thomas F. Harrelson ◽  
Makena Dettmann ◽  
Christoph Scherer ◽  
Denis Andrienko ◽  
Adam J. Moulé ◽  
...  

AbstractInelastic neutron scattering (INS) provides a weighted density of phonon modes. Currently, INS spectra can only be interpreted for perfectly crystalline materials because of high computational cost for electronic simulations. INS has the potential to provide detailed morphological information if sufficiently large volumes and appropriate structural variety are simulated. Here, we propose a method that allows direct comparison between INS data with molecular dynamics simulations, a simulation method that is frequently used to simulate semicrystalline/amorphous materials. We illustrate the technique by analyzing spectra of a well-studied conjugated polymer, poly(3-hexylthiophene-2,5-diyl) (P3HT) and conclude that our technique provides improved volume and structural variety, but that the classical force field requires improvement before the morphology can be accurately interpreted.


Author(s):  
Marcus Korb ◽  
Xianming Liu ◽  
Sebastian Walz ◽  
Julia Mahrholdt ◽  
Alexey A. Popov ◽  
...  

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