Syntheses of Cytosporones A, C, J, K, and N, Metabolites from Medicinal Fungi

2015 ◽  
Vol 68 (10) ◽  
pp. 1583 ◽  
Author(s):  
Andrew M. Beekman ◽  
Russell A. Barrow
Keyword(s):  
Natural Products ◽  
Selective Reduction ◽  
Complete Characterization ◽  
Phenyl Acetate ◽  
Human Pathogens ◽  
Medicinal Fungi ◽  
C And N ◽  
Key Steps ◽  
First Time

The syntheses of the fungal metabolites cytosporones A, (±)-C, and N are reported. And the syntheses of cytosporones J and K are described for the first time. The preparation of racemic cytosporone J and racemic cytosporone K, natural products containing the rare 3-isochromanone substructure, was achieved in 8 linear steps with an overall yield of 45 % and 7 linear steps in 46 % yield, respectively, resulting in the complete characterization of these compounds for the first time. The key steps included a recently described homologation of benzoic acid to the analogous phenyl acetate using Birch reductive alkylation conditions, acylation of the appropriate phenyl acetate derivative, and a selective reduction and spontaneous biomimetic lactonization to yield the 3-isochromanone skeleton. The synthesized natural products were evaluated for their biological activity against several clinical strains of human pathogens with all compounds displaying weak antimicrobial activity.

Tropical Marine Algae. IX. A New Sesquiterpenoid Metabolite From the Red Alga Laurencia marianensis

1993 ◽  
Vol 46 (6) ◽  
pp. 933 ◽  
Author(s):  
R Denys ◽  
JC Coll ◽  
BF Bowden
Keyword(s):  
Natural Products ◽  
Marine Algae ◽  
Red Alga ◽  
Natural Products Chemistry ◽  
First Time

An investigation of the natural products chemistry of the red alga Laurencia marianensis Yamada, a species whose chemistry has not previously been described in the literature, yielded the new metabolite 1-[(3′S*,3a′lR*,4′R*,7′S*,7a′S*)-7′-bromo-7a′-methyl-3′-(1′-methylethyl)octahydro-1′H-inden-4′-yl] ethanone (1) and the known metabolites deoxyprepacifenol (2) and pacifenol (3). The full n.m.r. characterization of (2) and (3) is reported for the first time.

scholarly journals Identification and Characterization of a Rhodopsin Kinase Gene in the Suckers of Octopus vulgaris: Looking around Using Arms?

Biology ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 936
Author(s):  
Al-Sayed Al-Soudy ◽  
Valeria Maselli ◽  
Stefania Galdiero ◽  
Michael J. Kuba ◽  
Gianluca Polese ◽  
...  
Keyword(s):  
3D Structure ◽  
Complete Characterization ◽  
Octopus Vulgaris ◽  
Kinase Gene ◽  
Light Sensing ◽  
Rhodopsin Kinase ◽  
First Time ◽  
Identification And Characterization

In their foraging behavior octopuses rely on arm search movements outside the visual field of the eyes. In these movements the environment is explored primarily by the suckers that line the entire length of the octopus arm. In this study, for the first time, we report the complete characterization of a light-sensing molecule, Ov-GRK1, in the suckers, skin and retina of Octopus vulgaris. We sequenced the O. vulgaris GRK1 gene, defining a phylogenetic tree and performing a 3D structure model prediction. Furthermore, we found differences in relative mRNA expression in different sucker types at several arm levels, and localized it through in situ hybridization. Our findings suggest that the suckers in octopus arms are much more multimodal than was previously shown, adding the potential for light sensing to the already known mechanical and chemical sensing abilities.

A study of the mineralization of bone by high voltage EM tomography

1992 ◽  
Vol 50 (1) ◽  
pp. 582-583
Author(s):  
James Arena ◽  
Bruce F. McEwen ◽  
Min Ja Song ◽  
William J. Landis
Keyword(s):  
High Voltage ◽  
Three Dimensional ◽  
Structural Features ◽  
Complete Characterization ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Vertebrate Model ◽  
Em Tomography ◽  
First Time

Complete characterization of the inorganic and organic interaction in calcifying tissues is fundamental to understanding their structure-function relations. In this context, high resolution tomographic three-dimensional (3D) reconstruction of normally calcifying avian tendon imaged by high voltage electron microscopy has recently been used to determine specific structural features of hydroxyapatite crystals associated with collagen fibrils in this vertebrate model of biological mineralization. The present work is an extension of these previous investigations, now applied to bone for the first time.

scholarly journals Objective Clustering of Proteins Based on Subcellular Location Patterns

2005 ◽  
Vol 2005 (2) ◽  
pp. 87-95 ◽  
Author(s):  
Xiang Chen ◽  
Robert F. Murphy
Keyword(s):  
Subcellular Location ◽  
Complete Characterization ◽  
Sequence Motifs ◽  
Automated Method ◽  
Single Location ◽  
Starting Point ◽  
Location Patterns ◽  
Limited Protein ◽  
First Time

The goal of proteomics is the complete characterization of all proteins. Efforts to characterize subcellular location have been limited to assigning proteins to general categories of organelles. We have previously designed numerical features to describe location patterns in microscope images and developed automated classifiers that distinguish major subcellular patterns with high accuracy (including patterns not distinguishable by visual examination). The results suggest the feasibility of automatically determining which proteins share a single location pattern in a given cell type. We describe an automated method that selects the best feature set to describe images for a given collection of proteins and constructs an effective partitioning of the proteins by location. An example for a limited protein set is presented. As additional data become available, this approach can produce for the first time an objective systematics for protein location and provide an important starting point for discovering sequence motifs that determine localization.

Pigments of Fly Agaric (Amanita muscaria)

2007 ◽  
Vol 62 (11-12) ◽  
pp. 779-785 ◽  
Author(s):  
Florian Stintzing ◽  
Willibald Schliemann
Keyword(s):  
Complete Characterization ◽  
Pigment Composition ◽  
High Susceptibility ◽  
Amanita Muscaria ◽  
Pigment Pattern ◽  
Starting Point ◽  
First Time ◽  
Derivatives Of ◽  
Comprehensive Characterization

The complex pigment pattern of fly agaric (Amanita muscaria) cap skins has been studied by LC-DAD and mass spectrometry. Among the betaxanthins the corresponding derivatives of serine, threonine, ethanolamine, alanine, Dopa, phenylalanine and tryptophan are reported for the first time to contribute to the pigment pattern of fly agarics. Betalamic acid, the chromophoric precursor of betaxanthins and betacyanins, muscaflavin and seco-dopas were also detected. Furthermore, the red-purple muscapurpurin and the red muscarubrin were tentatively assigned while further six betacyanin-like components could not be structurally allocated. Stability studies indicated a high susceptibility of pigment extracts to degradation which led to rapid colour loss thus rendering a complete characterization of betacyaninlike compounds impossible at present. Taking into account these difficulties the presented results may be a starting point for a comprehensive characterization of the pigment composition of fly agarics.

scholarly journals Description of Treponema azotonutricium sp. nov. and Treponema primitia sp. nov., the First Spirochetes Isolated from Termite Guts

2004 ◽  
Vol 70 (3) ◽  
pp. 1315-1320 ◽  
Author(s):  
Joseph R. Graber ◽  
Jared R. Leadbetter ◽  
John A. Breznak
Keyword(s):  
New Species ◽  
16S Rrna ◽  
Complete Characterization ◽  
Free Living ◽  
16S Rrna Sequence ◽  
Gene Encoding ◽  
Phenotypic Properties ◽  
First Time ◽  
Specific Epithets

ABSTRACT Long after their original discovery, termite gut spirochetes were recently isolated in pure culture for the first time. They revealed metabolic capabilities hitherto unknown in the Spirochaetes division of the Bacteria, i.e., H2 plus CO2 acetogenesis (J. R. Leadbetter, T. M. Schmidt, J. R. Graber, and J. A. Breznak, Science 283:686-689, 1999) and dinitrogen fixation (T. G. Lilburn, K. S. Kim, N. E. Ostrom, K. R. Byzek, J. R. Leadbetter, and J. A. Breznak, Science 292:2495-2498, 2001). However, application of specific epithets to the strains isolated (Treponema strains ZAS-1, ZAS-2, and ZAS-9) was postponed pending a more complete characterization of their phenotypic properties. Here we describe the major properties of strain ZAS-9, which is readily distinguished from strains ZAS-1 and ZAS-2 by its shorter mean cell wavelength or body pitch (1.1 versus 2.3 μm), by its nonhomoacetogenic fermentation of carbohydrates to acetate, ethanol, H2, and CO2, and by 7 to 8% dissimilarity between its 16S rRNA sequence and those of ZAS-1 and ZAS-2. Strain ZAS-9 is proposed as the type strain of the new species, Treponema azotonutricium. Strains ZAS-1 and ZAS-2, which are H2-consuming, CO2-reducing homoacetogens, are proposed here to be two strains of the new species Treponema primitia. Apart from the salient differences mentioned above, the genomes of all three strains were similar in size (3,461 to 3,901 kb), in G+C content (50.0 to 51.0 mol%), and in possession of 2 copies of the gene encoding 16S rRNA (rrs). For comparison, the genome of the free-living spirochete Spirochaeta aurantia strain J1 was analyzed by the same methods and found to have a size of 3,719 kb, to contain 65.6 mol% G+C, and also to possess 2 copies of the rrs gene.

scholarly journals Stereoselective chromium- and molybdenum-mediated transformations of arenes

2004 ◽  
Vol 76 (3) ◽  
pp. 689-695 ◽  
Author(s):  
E. P. Kündig ◽  
Rita Cannas ◽  
C.-H. Fabritius ◽  
Gabriele Grossheimann ◽  
Mikhail Kondratenko ◽  
...  
Keyword(s):  
Natural Products ◽  
Metal Complexes ◽  
Final Section ◽  
Claisen Rearrangement ◽  
Arene Complexes ◽  
Asymmetric Syntheses ◽  
Rapid Access ◽  
Arene Complex ◽  
Key Steps ◽  
First Time

Tricarbonylchromium-mediated dearomatization provides a rapid access to substituted cyclohexadienes. Efficient asymmetric routes to planar chiral arene complexes and to substituted cyclohexadienes have been developed. The article sums up the main features of this chemistry. Highly enantiomerically enriched ortho-substituted benzaldehyde complexes are accessible via asymmetric lithiation followed by trapping with electrophiles. In different solvents, the trimethylsilyl complex exhibits [alpha] values ranging from −174 to +108 for the same enantiomer. Details of two asymmetric syntheses of natural products are given: the alkaloid lasubine I starting from a highly enantiomerically enriched planar chiral arene complex and the marine furanosesquiterpene acetoxytubipofuran. The latter is assembled via asymmetric dearomatization of a benzaldehyde imine complex. Other key steps include an Eschenmoser–Claisen rearrangement and a regio- and diastereoselective Pd-catalyzed allylic substitution. The final section deals with labile arene metal complexes. For the first time, dearomatization reactions mediated by the Mo(CO)3 group have been realized. The reactions show strong analogies to the Cr(CO)3-mediated reactions, but exhibit also marked differences: the arene–Mo bond is stronger, but more labile, and the sequential double additions show different selectivities compared to the chromium analogs.

SYNTHESIS AND CHARACTERIZATION OF A HIGHLY CRYSTALLINE NOVEL MESOPOROUS C- AND N-CODOPED TiO2 NANOPHOTOCATALYST

NANO ◽  
2008 ◽  
Vol 03 (05) ◽  
pp. 367-372 ◽  
Author(s):  
SRINIVASAN ANANDAN ◽  
YASURO IKUMA ◽  
KATSUYOSHI KAKINUMA ◽  
KOICHI NIWA
Keyword(s):  
High Surface ◽  
3D Structure ◽  
High Surface Area ◽  
Titanium Tetraisopropoxide ◽  
Tem Analysis ◽  
Light Region ◽  
C And N ◽  
First Time ◽  
Uniform Pore Size

Here we report, for the first time, the synthesis of highly crystalline novel mesoporous carbon/nitrogen ( C / N )-codoped TiO 2 (MCNT) using ethylene diamine and carbon tetrachloride as the source for nitrogen and carbon, KIT-6 as the template, and titanium tetraisopropoxide as the TiO 2 source. The obtained material has been unambiguously characterized by various sophisticated techniques. XRD and TEM analysis revealed that the MCNT material possesses highly crystalline 3D structure with a continuous network of mesoporous channels as well as structure corresponding to TiO 2. UV-DRS analysis indicated that light absorption shifted to lower energy and stronger absorption in the visible light region. XPS revealed that C and N were doped effectively and C or N dopants might be present in the chemical environment of Ti – O – N or Ti – O – C . It has been found that the material is highly crystalline and possesses high surface area, pore volume and uniform pore size distribution. Owing to its textural characteristics, it could be useful for various applications, such as photocatalysis, fuel cells, bulky biomolecule adsorption and nanotechnology.

scholarly journals Use of (S)-trans-γ-Monocyclofarnesol as a Useful Chiral Building Block for the Stereoselective Synthesis of Diterpenic Natural Products

2014 ◽  
Vol 9 (3) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Stefano Serra ◽  
Alessandra A. Cominetti ◽  
Veronica Lissoni
Keyword(s):  
Natural Products ◽  
Building Block ◽  
Stereoselective Synthesis ◽  
Allyl Acetate ◽  
Chiral Building Block ◽  
Sulfone Derivative ◽  
Key Steps ◽  
First Time ◽  
Unambiguous Assignment ◽  
Comprehensive Study

A comprehensive study of the exploitation of ( S)- trans-γ-monocyclofarnesol as a useful chiral building block for the stereoselective synthesis of natural diterpene derivatives is here described. The farnesol derivative (+)-1 was used as starting material in the preparation of the diterpenes ( S)-dehydroambliol-A and ( S)-trixagol, as well as for the syntheses of the dinorditerpene ( S)-dinortrixagone and of the guanidine-interrupted terpenoid ( S)-dotofide. Key steps of the presented syntheses were the cross-coupling between an allyl acetate and a Grignard reagent, the Wittig reaction, the selective preparation of a diacylguanidine derivative and the alkylation of a sulfone derivative, followed by the reductive removal of the same functional group. It is worth noting that the natural products (+)-8, (+)-12 and (+)-15 were prepared stereoselectively for the first time, thus allowing the unambiguous assignment of their absolute configuration.

scholarly journals High Yielding, One-Pot Synthesis of Bis(1H-indazol-1-yl)methane Catalyzed by 3d-Metal Salts

Reactions ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 59-69
Author(s):  
Natalie M. Lind ◽  
Natalie S. Joe ◽  
Brian S. Newell ◽  
Aimee M. Morris
Keyword(s):  
High Resolution Mass Spectrometry ◽  
Structural Similarity ◽  
Complete Characterization ◽  
X Ray Diffraction ◽  
One Pot ◽  
One Pot Synthesis ◽  
Potential Applications ◽  
Metal Catalyzed ◽  
First Time

Synthetic access to poly(indazolyl)methanes has limited their study despite their structural similarity to the highly investigated chelating poly(pyrazolyl)methanes and their potentially important indazole moiety. Herein is presented a high yielding, one-pot synthesis for the 3d-metal catalyzed formation of bis(1H-indazol-1-yl)methane from 1H-indazole utilizing dimethylsulfoxide as the methylene source. Complete characterization of bis(1H-indazol-1-yl)methane is given with 1H and 13C NMR, UV/Vis, FTIR, high resolution mass spectrometry and for the first time, single crystal X-ray diffraction. This simple, inexpensive pathway to yield exclusively bis(1H-indazol-1-yl)methane provides synthetic access to further investigate the coordination and potential applications of the family of bis(indazolyl)methanes.

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