Various algorithms comparing 2D NMR spectra have been explored for their ability to dereplicate natural products as well as determine molecular structures. However, spectroscopic artefacts, solvent effects, and the interactive effect of functional group(s) on chemical shifts combine to hinder their effectiveness. Here, we leveraged Non-Uniform Sampling (NUS) 2D NMR techniques and deep Convolutional Neural Networks (CNNs) to create a tool, SMART, that can assist in natural products discovery efforts. First, an NUS heteronuclear single quantum coherence (HSQC) NMR pulse sequence was adapted to a state-of-the-art nuclear magnetic resonance (NMR) instrument, and data reconstruction methods were optimized, and second, a deep CNN with contrastive loss was trained on a database containing over 2,054 HSQC spectra as the training set. To demonstrate the utility of SMART, several newly isolated compounds were automatically located with their known analogues in the embedded clustering space, thereby streamlining the discovery pipeline for new natural products.
Integrins are the adhesion molecules and receptors of extracellular matrix (ECM). They mediate the interactions between cells-cells and cells-ECM. The crosstalk between cancer cells and their microenvironment triggers a variety of critical signaling cues and promotes the malignant phenotype of cancer. As a type of transmembrane protein, integrin-mediated cell adhesion is essential in regulating various biological functions of cancer cells. Recent evidence has shown that integrins present on tumor cells or tumorassociated stromal cells are involved in ECM remodeling, and as mechanotransducers sensing changes in the biophysical properties of the ECM, which contribute to cancer metastasis, stemness and drug resistance. In this review, we outline the mechanism of integrin-mediated effects on biological changes of cancers and highlight the current status of clinical treatments by targeting integrins.
A new alternariol derivative, 2240B (1), together with alternariol (2), alternariol 4, 10-dimethyl ether (3), and alternariol 4-methyl ether (4), was isolated from the ethyl acetate extract of the liquid medium GYT of No. 2240, the mangrove endophytic fungus from the South China Sea Coast. The structure of compound 1 was unambiguously elucidated as alternariol 4-methyl-10-acethyl ester by spectra including one/twodimensional NMR, HREIMS, IR, and UV. The structures of compounds 2-4 were also established by spectroscopic analyses and comparison with related literature data. The anticancer tests showed that compounds 2 and 4 had strong activities against KB and KBv200 cells with IC 50 values of 3.17, 3.12, and 4.82, 4.94 μg/mL, while compounds 1 and 3 exhibited weak activities against the two kinds of tumor lines with IC 50 values of more than 50 μg/mL. Key words: alternariol derivatives, mangrove endophytic fungus, alternariol 4-methyl-10-acethyl ester, mutagenicity, KB tumor lines, KBv200. 1: R 1 = OMe, R 2 = Ac; 2: R 1 = R 2 = OH 3: R 1 = R 2 = OMe; 4: R 1 = OMe, R 2 = OH
A perfusion-based high cell density (HD) cell banking process has been developed that offers substantial advantages in time savings and simplification of upstream unit operations. HD cell banking provides the means to reduce the time required for culture inoculum expansion and scale-up by eliminating the need for multiple small to intermediate scale shake flask-based operations saving up to 9 days of operation during large-scale inoculum expansion. HD perfusion cultures were developed and optimized in a disposable Wave bioreactor system. Through optimization of perfusion rate, rocking speed and aeration rate, the perfusion system supported peak cell densities of >20 × 10(6) cells/mL while maintaining high cell viability (≥ 90%). The cells were frozen at HD (90-100 × 10(6) viable cells/mL) in 5-mL CryoTube vials. HD cell banks were demonstrated to enable direct inoculation of culture into a Wave bioreactor in the inoculum expansion train thus eliminating the need for intermediate shake flask expansion unit operations. The simplicity of the disposable perfusion system and high quality of the cell banks resulted in the successful implementation in a 2000 L scale manufacturing facility.
A new monosesquiterpene diacetylgliocladic acid (1), a new dimeric sesquiterpene divirensol H (9), and two exceptionally novel trimeric sesquiterpene trivirensols A and B (11 and 12), together with another eight known congeners, were purified from an endophytic fungus Trichoderma virens FY06, derived from Litchi chinensis Sonn. whose fruit is a delicious and popular food. All of them were identified by comprehensive spectroscopic analysis, combined with biosynthetic considerations. Trivirensols A and B are unprecedented trimers of which three subunits are connected by two ester bonds of the sesquiterpene class. Relative to the positive control triadimefon, all the tested metabolites showed strong inhibitory activities against at least one phytopathogenic fungus among Penicillium italicum, Fusarium oxysporum, Fusarium graminearum, Colletotrichum musae, and Colletotrictum gloeosporioides. Notably, as metabolites of the endophytic fungus from L. chinensis, they all presented strong antifungal activities against C. gloeosporioides which causes anthracnose in L. chinensis.
Due to the increasing prevalence of multidrug-resistant Mycobacterium tuberculosis, there is an urgent need for new antituberculosis drugs that have novel mechanisms of action. As part of our ongoing search for antimycobacterial metabolites from mangrove endophytes, chemical analysis of the active extract of a strain of Fusarium sp. was performed, which led to the isolation of fusaric acid as the predominant constituent. A variety of metal complexes of fusaric acid were prepared. Antimycobacterial assays showed that Cadmium (II) and Copper (II) complexes exhibited potent inhibitory activity against the M. bovis BCG strain [minimum inhibitory concentration (MIC) = 4 μg/mL] and the M. tuberculosis H37Rv strain (MIC = 10 μg/mL), respectively. This is the first report of the antimycobacterial activity of the mangrove Fusarium metabolite and its coordinating metal complexes.
Five isocoumarin derivatives including three new compounds, aspergisocoumrins A-C (1-3), together with two known analogues, 8-dihydroxyisocoumarin-3-carboxylic acid (4) and dichlorodiaportin (5) were obtained from the culture of the endophytic fungus Aspergillus sp. HN15-5D derived from the fresh leaves of the mangrove plant Acanthus ilicifolius. Their structures were elucidated using comprehensive spectroscopic methods. The double bond geometry of compounds 1 and 2 were assigned as E and Z on the basis of the distinct coupling constants, respectively. Compounds 1 and 2 showed cytotoxicity against MDA-MB-435 with IC values of 5.08 ± 0.88 and 4.98 ± 0.74 μM, respectively.
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