A New Taxoid from Microbial Transformation

A new taxoid taxa-4(20), 11-diene-2α, 5β, 10β, 14β-tetraol-2α, 14β-diacetate (sinenxan H) (1) was obtained by biotransformation of taxa-4(20), 11-diene-2α, 5α, 10β, 14β-tetraol-2α, 5α, 10β, 14β-tetraacetate (2) with a fungus isolated from Taxus yunnanensis. Its structure was determined based on spectral data

Microbial transformation for Region-selective Hydroxylation of Z-Butylidenephthalide by Aspergillus niger CGMCC 3.739

Microbial transformation is a useful tool for structure modification of active natural products.Z-Butylidenephthalide is the main active constituent of Angelica sinensis.In the present work,a pair of new oxidized metabolites,namely(-)(11R)-(Z)-11-hydroxy-butylidenephthalide(1a)and(+)(11S)-(Z)-11-hydroxy-butylidenephthalide(1b),were obtained from microbial transformation for region-selective 11-hydroxylation of Z-butylidenephthalide by Aspergillus niger CGMCC 3.739.Their structures,including absolute configurations,were elucidated by extensive analysis of HR-ESI-MS,NMR spectra,and the modified Mosher’s method.This is the first study on the microbial transformation of Z-butylidenephthalide,and these findings offer a tool for region-selective 11-hydroxylation of Z-butylidenephthalide.

Isolation and microbial transformation of tea sapogenin from seed pomace of Camellia oleifera with anti-inflammatory effects

In the current study,tea saponin,identified as the primary bioactive constituent in seed pomace of Camellia oleifera Abel.,was meticulously extracted and hydrolyzed to yield five known sapogenins:16-O-tiglogycamelliagnin B(a),camelliagnin A(b),16-O-angeloybarringtogenol C(c),theasapogenol E(d),theasapogenol F(e).Subsequent biotransformation of compound a facilitated the isolation of six novel metabolites(a1−a6).The anti-inflammatory potential of these compounds was assessed using pathogenassociated molecular patterns(PAMPs)and damage-associated molecular patterns molecules(DAMPs)-mediated cellular inflammation models.Notably,compounds b and a2 demonstrated significant inhibitory effects on both lipopolysaccharide(LPS)and high-mobility group box 1(HMGB1)-induced inflammation,surpassing the efficacy of the standard anti-inflammatory agent,carbenoxolone.Conversely,compounds d,a3,and a6 selectivity targeted endogenous HMGB1-induced inflammation,showcasing a pronounced specificity.These results underscore the therapeutic promise of C.oleifera seed pomace-derived compounds as potent agents for the management of inflammatory diseases triggered by infections and tissue damage.

Microbial transformation of isoangustone A by Mucor hiemalis CGMCC 3.14114

Isoangustone A （1） is an isoprenylated flavonoid isolated from licorice. It has been reported to possess anti-microbial, anti-oxidative, anti-inflammatory, and anti-tumor activities. In order to increase its structural diversity, microbial transformation of 1 was conducted by Mucor hiemalis CGMCC 3.14114 to obtain three new compounds. By extensive NMR and MS spectroscopic analyses, their structures were identified as isoangustone A 7-O-glucoside （2）, isoangustone A 7-O-glucoside-4＇-O-sulfate （3）, and isoangustone A 7,3 ＇di-O-glucoside （4）, respectively. The major biotransformation reaction was glycosylation at C-7. Sulfation is rare for microbial transformation.

Microbial transformation of lovastatin by Beauveria bassiana

Microbial transformation of lovastatin(1)by resting cells of a filamentous fungus,Beauveria bassiana AS 3.4270,yielded five metabolites(2-6),which were unambiguously characterized by various spectroscopic data analyses.The occurred reactions included hydroxyla-tion,lactone hydrolysis and methylation.The inhibitory effects of all metabolites on the 3-hydroxy-3-methylglutaryl coenzyme A(HMG-CoA)reductase were evaluated.Of the five compounds,4 ex hibited comparable inhibitory effect to lovastatin on the HMG-CoA reductase with ICso value of 2.2μM,and inhibitory rate of 81.4%.

Microbial transformation of glycyrrhetinic acid and potent neural anti-inflammatory activity of the metabolites

The microbial transformation of glycyrrhetinic acid（1） by Cunninghamella blakesleana CGMCC 3.970 led to the production of five new metabolites（2-6）.The structures of the metabolites were determined by extensive spectroscopic（HR-ESIMS,1D and 2D NMR） data analyses.The involved reactions exhibited specific hydroxylations at C-24,C-7,and C-15,and oxidation at C-3.Moreover,compounds 2,5,and 6showed significant neural anti-inflammatory activity by inhibiting lipopolysaccharide-induced NO production in mouse microglia BV2 cells with IC（50） values of 0.76,0.94,and 0.16μmol/L,respectively.

Refractory humic-like dissolved organic matter fuels microbial communities in deep energy-limiting marine sediments

Humic-like dissolved organic matter(DOM),usually regarded as refractory,is a major component of DOM in marine sediment pore waters.However,its bio-reactivity remains poorly explored in natural environments,which makes its roles in supporting subsurface microbial communities and regulating long-term carbon cycling elusive.Here,the bio-reactivity of humiclike DOM was evaluated by modeled reaction rates together with its interactions with microbial communities in five sediment cores collected from the eutrophic Pearl River Estuary to the oligotrophic deep-sea basin in the northern South China Sea.We revealed contrasting relationships between humic-like DOM and microbes in the coastal and deep-sea sediments.In eutrophic coastal sediments,specific microbial groups enriched in the deep layers co-varied with humic-like DOM,while most microbial groups were significantly correlated with protein-like DOM,microbial transformation of which likely resulted in the production of humic-like DOM.On the contrary,in energy-limiting deep-sea sediments,over 70%of the microbial groups were found closely correlated with humic-like DOM,a net consumption of which was demonstrated in deep layers.The consumption of humic-like DOM in deep-sea sediments reduced its total production flux in the uppermost~5-meter layer to about one-tenth of that in coastal sediments,which could consequently decrease the refractory DOM flux to the overlying seawater and influence long-term oceanic carbon cycling.

Hydroxylation of nigranoic acid to 6β-hydroxynigranoic acid by Caryospora carllicarpa YMF1.01026

Microbial transformation of nigranoic acid by Caryospora carllicarpa YMF1.01026 afforded the new derivative 6β-hydroxynigranoic acid. Its structure was elucidated by spectroscopic methods.

Microbial Hydroxylation of Quinovic Acid Glycoside by Streptomyces griseus ACCT 13273

Microbial transformation of a triterpene glycoside, quinovic acid 3-O-β-D-quinovopyranoside by Streptomyces griseus ACCT 13273 was achieved with the aim of generating new bio-active derivatives. Preparative-scale biotransformation with standard two-stage fermentation protocol afforded a new oxidized metabolite, as a result of the hydroxylation of the methyl group at C-30, which was difficult to achieve by chemical means. The metabolite was elucidated based on extensive NMR and high-resolution mass spectral analyses.

Biodegradation of Benzo[a]pyrene by Arthrobacter oxydans B4

A bacterial strain, Arthrobacter oxydans （B4）, capable of degrading benzo[a]pyrene （BaP） in water body, was isolated from a polycyclic aromatic hydrocarbons-contaminated site. Effects of different factors, such as reaction time, pH value, temperature and organic nutrients, on BaP biodegradation by the strain B4 were studied. After 5 d treatment, the concentration of BaP in mineral salts medium was reduced to 0.318 mg L-1, compared to the initial concentration of 1.000 mg L-1. There was a process of acid formation during the degradation with pH falling from initial 7.01 to 4.61 at 5 d, so keeping the water body under slightly alkaline condition was propitious to BaP degradation. Strain B4 efficiently degraded BaP at 20 to 37 ~C with addition of organic nutrients. The biodegradation and transformation of BaP mainly occurred on cell surfaces, and extracellular secretions played an important role in these processes. Fourier transform infrared spectroscopy and gas chromatograph-mass spectrometer analyses of metabolites showed that ring cleavage occurred in the BaP degradation process and the resulting metabolically utilizable substrates were generated as sole carbon sources for B4 growth. Furthermore, mineralization extent of metabolites was verified by determining the total organic carbon and inorganic carbon in the degradation system.

Regio- and stereo-selective hydroxylations of ingenane diterpenoids by Mortierella ramanniana and Gibberella fujikuroi

The regio- and stereo-selective hydroxylations of two ingenane diterpenoids, 20-deoxyingenol(1) and 13-oxyingenol dodecanoat(2), by the filamentous fungi Mortierella ramanniana and Gibberella fujikuroi were investigated in the present study. Four undescribed metabolites(3–6) of substrate 1 and two undescribed metabolites(7 and 8) of substrate 2 were isolated. All the lites were identified as hydroxylated ingenane derivatives by extensive NMR and HR-ESI-MS data analyses. All the biotransformed compounds and the substrates were evaluated for their cytotoxicities against three human cancer cell lines, including human colon cancer Caco-2, breast cancer MCF-7, and adriamycin(ADM)-resistant MCF-7/ADM cell lines. All ingenane alcohols(1, and 3–6) displayed no significant cytotoxic activities. The substrate 13-oxyingenol dodecanoat(2) showed moderate cytotoxicity with IC50 values being 35.59 ± 5.37 μmol·L^(-1)(Caco-2), 24.04 ± 4.70 μmol·L^(-1)(MCF-7), and 22.24 ± 5.19 μmol·L^(-1)(MCF-7/ADM). However, metabolites 7 and 8 displayed no significant cytotoxicity. These results indicated that the hydroxylation at the C^(-1)3 aliphatic acid ester of substrate 2 can significantly reduce the cytotoxic activity.

Metagenomes of polyamine-transforming bacterioplankton along a nearshore-open ocean transect

Short-chained aliphatic polyamines (PAs) have recently been recognized as an important carbon, nitrogen, and/or energy source for marine bacterioplankton. To study the genes and taxa involved in the transformations of different PA compounds and their potential variations among marine systems, we collected surface bacterioplankton from nearshore, offshore, and open ocean stations in the Gulf of Mexico and examined their metagenomic responses to additions of single PA model compounds (putrescine, spermidine, or spermine). Genes affiliated with PA uptake and all three known PA degradation pathways, i.e., transamination, γ-glutamylation, and spermidine cleavage, were significantly enriched in most PA-treated metagenomes. In addition, identified PA-transforming taxa were mostly the alpha and gamma classes of Proteobacteria, with less important contributions from members of Betaproteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, and Planctomycetes. These findings suggest that PA transformations are ubiquitous, have diverse pathways, and are carried out by a broad range of the bacterioplankton taxa in the Gulf of Mexico. Identified PA-transforming bacterial genes and taxa were different among nearshore, offshore, and open ocean sites, but were little different among individual compound-amended metagenomes at any specific site. These observations further indicate that PA-transforming taxa and genes are site-specific and with high similarities among PA compounds.