Biosynthesis of Unsaturated Fatty Acids via Mortierella Isabellina Cultivated in a Medium Containing Butanol

IntroductionThe biosynthesis of unsaturated fatty acidshasattracted more attention in recent years. Forexample,linoleic and linolenic acids are importantmaterials for pharmaceutical and food industries.Besides,they can be used to synthesize paint,printing ink and surfactant,etc. A number ofmicroorganisms have been studied as potentialcommercial sources to produce unsaturated fattyacids[1] .Agricultural and industrial products,by-products,etc. have been employed in thecultivation of those orga…     

Cascade reactions leading to the mechanism of action of vinaxanthone and xanthofulvin,natural products that drive nerve repair

The natural products vinaxanthone and xanthofulvin promote regeneration in animal models of spinal cord injury and corneal transplant. However, inhibition of the initially described biological target of these compounds, semaphorin 3A, does not fully account for the recovery demonstrated in vivo following administration of the natural products. Through chemical synthesis substantial quantities of both natural products have been accessed with early reaction development paving the way for synthesizing both compounds. The success of a model system, first disclosed herein, translated to the syntheses of both natural products. Following from this we also report for the first time the discovery of a new target of the natural products, the succinate receptor 1 (SUCNR1). Both natural products function as positive allosteric modulators of SUCNR1. As the first known allosteric modulators of SUCNR1, the compounds represent powerful new tools to understand the pharmacology of SUCNR1 and its control of growth and cellular defense.     

Direct formation of chromopyrrolic acid from indole-3-pyruvic acid by StaD, a novel hemoprotein in indolocarbazole biosynthesis

Indole-3-pyruvic acid was transformed to chromopyrrolic acid by a novel heme-containing enzyme StaD responsible for staurosporine biosynthetic pathway in Streptomyces sp. TP-A0274.     

Identification of the biosynthetic units of Cypridina luciferin in Cypridina (Vargula) hilgendorfii by LC/ESI-TOF-MS

In a luminous ostracod Cypridina (Vargula) hilgendorfii, Cypridina luciferin with an imidazopyrazinone structure (3,7-dihydroimidazopyrazin-3-one) is utilized for the luminescence reaction. To identify the biosynthetic units of Cypridina luciferin, the stable isotope labeled compounds were examined by feeding experiments with living Cypridina specimens. The incorporation of the labeled compounds into Cypridina luciferin was identified by the method of LC/ESI-TOF-MS analyses and these results suggested that l-tryptophan, l-arginine and l-isoleucine are structural units of Cypridina luciferin.     

Microbial synthesis of natural,semisynthetic, and new-to-nature tetrahydroisoquinoline alkaloids

The tetrahydroisoquinoline (THIQ) moiety forms the backbone of several natural, synthetic, and semisynthetic drugs approved for the treatment of cancer, pain, gout, and various neurodegenerative diseases. Plants synthesize up to 3000 THIQ structures constituting the benzylisoquinoline, phenethylisoquinoline, Amaryllidaceae, and ipecac alkaloid classes. This review outlines the ongoing surge in activity surrounding the production of natural, semisynthetic, and new-to-nature THIQ metabolites in engineered microbial systems. These efforts have accelerated THIQ pathway discovery and engineering, unlocked new domains of chemical space, and spurred the development of highly productive microbial strains synthesizing unprecedented yields of THIQ precursors. Consolidating these advancements into a single bioprocess holds potential to outcompete crop-based manufacturing and total synthesis for the production of high-value THIQ pharmaceuticals at scale.     

Antimicrobial and cytotoxicity properties of biosynthesized gold and silver nanoparticles using D. brittonii aqueous extract

Recently, the production of nanoparticles using biological resources has gained considerable attention due to their application for animal and human well-being. In this study, we used a green synthesis to fabricate gold and silver nanoparticles by reducing HAuCl₄ and AgNO₃ into AuNPs and AgNPs, respectively, using Dudleya brittonii (DB) extract. The physio-chemical properties of the synthesized nanoparticles were analyzed using a UV–vis spectrophotometer, FESEM, EDX, HR-TEM, AFM and FT-IR. Furthermore, the antimicrobial and cytotoxicity activities of DB-AuNPs and DB-AgNPs against livestock pathogenic bacteria and different cell lines, as well as anti-oxidant activity, were investigated. DB synthesized AuNPs and AgNPs were mostly spherical with a few triangular rods and sizes ranging of 5–25 nm and 10–40 nm, respectively. The in vitro antibacterial and antifungal studies demonstrated the DB-AuNPs and DB-AgNPs have good antibacterial activity against E. coli and other livestock pathogens, including Y. pseudotuberculosis and S. typhi. Cell studies revealed that the higher concentrations of both DB-AuNPs and DB-AgNPs (1 µg/ml to 1 mg/ml) showed potent cytotoxicity in chicken cells after 24 hrs, whereas the middle and lower concentrations of DB-AuNPs and DB-AgNPs did not show cytotoxicity in selected cell lines after 24 hrs. In addition, the DB synthesized AuNPs and AgNPs exhibited good free scavenging activity in a dose-dependent manner. Therefore, the biosynthesized nanoparticles can be utilized by the livestock industry to develop an effective source against livestock microbial infections.     

Acyl and CO Ligands in the [Fe]-Hydrogenase Cofactor Scramble upon Photolysis

[Fe]-hydrogenase harbors the iron-guanylylpyridinol (FeGP) cofactor, in which the Fe(II) complex contains acyl-carbon, pyridinol-nitrogen, cysteine-thiolate and two CO as ligands. Irradiation with UV-A/blue light decomposes the FeGP cofactor to a 6-carboxymethyl-4-guanylyl-2-pyridone (GP) and other components. Previous in vitro biosynthesis experiments indicated that the acyl- and CO-ligands in the FeGP cofactor can scramble, but whether scrambling occurred during biosynthesis or photolysis was unclear. Here, we demonstrate that the [¹⁸O₁-carboxy]-group of GP is incorporated into the FeGP cofactor by in vitro biosynthesis. MS/MS analysis of the ¹⁸O-labeled FeGP cofactor revealed that the produced [¹⁸O₁]-acyl group is not exchanged with a CO ligand of the cofactor, indicating that the acyl and CO ligands are scrambled during photolysis rather than biosynthesis, which ruled out any biosynthesis mechanisms allowing acyl/CO ligands scrambling. Time-resolved infrared spectroscopy indicated that an acyl-Fe(CO)₃ intermediate is formed during photolysis, in which scrambling of the CO and acyl ligands can occur. This finding also suggests that the light-excited FeGP cofactor has a higher affinity for external CO. These results contribute to our understanding of the biosynthesis and photosensitive properties of this unique H₂-activating natural complex.     

Towards the biosynthesis of the aromatic products of the Mediterranean mollusc Scaphander lignarius: isolation and synthesis of analogues of lignarenones

Secondary metabolites of the Mediterranean mollusc Scaphander lignarius from different collection sites have been investigated, proving the constant presence of a number of minor metabolites correlated to the already known lignarenones. Complete characterization of the new metabolites has been supported by enantioselective synthesis. The data are consistent with the origin of this unique class of ω-phenyloctanoids from a common polyketide pathway.     

The biosynthesis of sorbicillinoids in Trichoderma sp. USF-2690: prospect for the existence of a common precursor to sorbicillinol and 5-epihydroxyvertinolide, a new sorbicillinoid member

Biosynthetic feeding studies of [1-¹³C], [2-¹³C], and [1,2-¹³C₂]-labeled sodium acetates into 5-epihydroxyvertinolide, a new sorbicillinoid, gives an incorporation pattern that proves the γ-lactone ring formation associated with a ring cleavage reaction of the precursor, a potential intermediate of sorbicillinol biosynthesis.     

深黄被孢霉催化转化十八醇合成不饱和脂肪酸

深黄被孢霉催化转化十八醇合成不饱和脂肪酸在优化转化条件下所得产物分析表明,干细胞中含油脂47.5%,蛋白质31.5%,碳水化合物28.9%.十八醇转化率为67.2%,油脂选择性为30.6%,产率20.6%.油脂中脂肪酸的选择性为:棕榈酸4.00%,棕榈油酸0.81%,硬脂酸0.95%,油酸20.75%,亚油酸1.95%,亚麻酸2.19%.催化转化条件下的研究表明,底物浓度越低,油脂和不饱和脂肪酸的选择性越好,当十八醇质量分数为0.5%时,油脂和不饱和脂肪酸的选择性达到最大值;培养基pH为中性时,获得了最大的油脂选择性和收率;33℃时醇转化率达最大值88%,23℃油脂产率达最大值9.7%.Mg²⁺对不饱和脂肪酸的生成有显著影响,当培养基中[Mg²⁺]=25mmol/L时,获得了最大的油脂选择性(25.7%)和产率(17.6%).