Biosynthesis of zinc oxide nanoparticles using Euphorbia milii leaf constituents: Characterization and improved photocatalytic degradation of methylene blue dye under natural sunlight

A facile biosynthesis route was followed to prepare zinc oxide nanoparticles (ZnO NPs) using Euphorbia milii (E. milii) leaf constituents. The SEM images exhibited presence of spherical ZnO NPs and the corresponding TEM images disclosed monodisperse nature of the ZnO NPs with diameter ranges between 12 and 20 nm. The Brunauer–Emmett–Teller (BET) analysis revealed that the ZnO NPs have specific surface area of 20.46 m²/g with pore diameter of 2 nm–10 nm and pore volume of 0.908 cm³/g. The EDAX spectrum exemplified the existence of Zn and O elements and non-appearance of impurities that confirmed pristine nature of the ZnO NPs. The XRD pattern indicated crystalline peaks corresponding to hexagonal wurtzite structured ZnO with an average crystallite size of 16.11 nm. The FTIR spectrum displayed strong absorption bands at 512 and 534 cm^?1 related to ZnO. The photocatalytic action of ZnO NPs exhibited noteworthy degradation of methylene blue dye under natural sunlight illumination. The maximum degradation efficiency achieved was 98.17% at an illumination period of 50 min. The reusability study proved considerable photostability of the ZnO NPs during photocatalytic experiments. These findings suggest that the E. milii leaf constituents can be utilized as suitable biological source to synthesis ZnO NPs for photocatalytic applications.     

Biosynthesis of aglajnes, polypropionate allomones of the opisthobranch mollusc Bulla striata

The biogenesis of aglajnes, polypropionate allomones of the cephalaspidean mollusc Bulla striata, has been investigated in vivo by feeding experiments. Incorporation of the committed precursor, [1-¹⁴C]-propionate, into aglajne-1 (1) and -3 (3) established the de novo origin of these compounds in B. striata. In the letter we also discuss briefly the ecological meaning of the origin of polypropionates in B. striata and in other cephalaspidean molluscs.     

Practical synthesis of 1-deoxy-d-xylulose and 1-deoxy-d-xylulose 5-phosphate allowing deuterium labelling

An optimised gram scale synthesis allows the production of 1-deoxy-d-xylulose and 1-deoxy-d-xylulose 5-phosphate with possible deuterium labelling at C-5. Such substrates are required for investigations on the mevalonate-independent 2-C-methyl-d-erythritol 4-phosphate pathway for isoprenoid biosynthesis in bacteria and chloroplasts of phototrophic eukaryotes and for the biosynthesis of vitamins B₁ (thiamine diphosphate) and B₆ (pyridoxol phosphate) in bacteria.     

Topical Problems in the Biosynthesis of Red Blood Pigment

Uroporphyrinogen III plays a key role in the biosynthesis of heme, the red pigment of blood. In vivo studies with specifically ¹⁴C- and ³H-labeled precursors have revealed that the formation uroporphyrinogen III in the organism follows several primary and subsidiary pathways. Model experiments on the pattern of biosynthesis have led to simple and effective methods of synthesizing uroporphyrin analogs and have shown that their production is strongly favored thermodynamically. The biologically porphyrins important thus available permit a mechanistic explanation of the light-induced dermatoses in porphyria diseases and suggest promising medical applications in diagnosis and therapy.     

Studies on the synthesis and biosynthesis of the fungal alkaloid necatorone

An alternative pathway for the biosynthesis of the fungal alkaloid necatorone has been studied using fluorine-labeled 3-(2-carboxyphenylamino)-l-tyrosine. Although no incorporation of this compound could be detected in feeding experiments with young specimens of Lactarius necator, an analogous 3-aminotyrosine derivative could be converted synthetically into the oxopyridoacridine core structure of necatorone. In experiments aimed at the synthesis of aaptamine-type alkaloids, an unprecedented cyclization of a 3-aminotyrosine-methyl propiolate adduct to a methyl isoquinoline-3-carboxylate was observed. A mechanism is proposed, in which C3 of the propiolate delivers C1 of the isoquinoline nucleus.     

Isolation and structure determination of a new lasso peptide subterisin from Sphingomonas subterranea

A new lasso peptide named subterisin was isolated from the culture broth of Sphingomonas subterranea NBRC 16086^T. The molecular formula of subterisin was established as C₇₈H₁₂₁O₂₂N₂₁ based on accurate mass analysis. The chemical structure of subterisin was determined by 2D NMR experiments. The presence of macrolactam ring of Gly1–Glu8 was indicated by NOESY experiment and MS/MS analysis. The three-dimensional structure of subterisin in solution was established by calculation based on NMR data. The proposed biosynthetic gene cluster of subterisin was found on the genome of S. subterranea.     

Enzymatic syntheses of unnatural head-to-tail pentacyclic triterpenes by tetraprenyl-β-curcumene cyclase

Little is known of the biosynthesis of sesquarterpenes and the synthesis of unnatural terpenoids by sesquarterpene biosynthetic enzymes has not yet been reported. In this study, the enzymatic cyclization of head-to-tail acyclic triterpene β-hexaprene—a natural product isolated from Bacillus clausii—using tetraprenyl-β-curcumene cyclase (TC) from Bacillus subtilis resulted in the formation of two unnatural pentacyclic triterpenes. It was revealed that B. subtilis TC, which forms tetracyclic terpenoid scaffold from tetraprenyl-β-curcumene in vivo, could be used to construct the 6/6/6/6/6-fused pentacyclic scaffold in vitro, suggesting that the active site cavity of TC has sufficient space to accommodate this unnatural pentacyclic scaffold. This is the first report demonstrating the utility of a sesquarterpene cyclase toward the synthesis of unnatural terpenoids.     

顺二醇类生物分子的硼亲和分子印迹研究进展EI北大核心CSCD

含顺二酚的分子,如糖类、糖苷和糖蛋白等,在糖组学、代谢组学和蛋白质组学等不同领域都有着至关重要的作用。但是这类样品分子通常存在于非常低丰度的环境中且与许多干扰化合物共存,给临床和生物学上的分离检测带来了巨大的困难。因此,开发建立对顺二醇类化合物简单高效的分离方法具有重要意义。分子印迹技术,是基于模拟生物体内抗原与抗体相互作用原理而发展起来的一种新兴技术,近年来因其特定的分子识别能力以及材料的稳定性和重复性而引起了广泛关注,也在顺二醇类化合物的分离方面得到了许多应用。本综述总结了在顺二醇类化合物的分子印迹方面的最新进展,并对其未来发展的方向和前景进行了讨论。     

Green synthesis of iron (Fe) nanoparticles using Plumeria obtusa extract as a reducing and stabilizing agent: Antimicrobial,antioxidant and biocompatibility studies

In the current study, a green and facile route for the synthesis of iron nanoparticles (FeNPs) was adopted. The FeNPs were fabricated via a single step green route using aqueous leaves extract of Plumeria obtusa (P. obtusa) as a capping/reducing and stabilizing agents. The FeNPs were characterized by UV/Vis (Ultraviolet/Visible), FTIR (Fourier Transform Infra-Red spectroscopy), TEM (Transmission Electron Microscopy), SEM (Scanning Electron Microscopy) and XRD (X-Ray Diffraction) techniques. The FeNPs were of spheroidal shape with average size of 50 nm. The biosynthesized FeNPs were further evaluated for their biological activities like antimicrobial, antioxidant and biocompatibility. The FeNPs displayed auspicious antimicrobial activity against bacterial (E. coli, B. subtilis) and fungal strains (A. niger) and S. commune. The test performed against red blood cells (RBCs) lysis (1.22 ± 0.02%) and macrophage (31 ± 0.09%) showed biocompatible nature of FeNPs. In vitro cytotoxicity against AU565 (82.03 ± 0.08–23.65 ± 0.065%) and HeLa (88.61 ± 0.06–33.34 ± 0.06%) cell lines showed cell viability loss in dose dependent manner (FeNPs 25–100 μg/mL). The antioxidant activities values were determined through DPPH, TRPA, NO and H₂O₂ assays with values 70.23 ± 0.02%, 76.65 ± 0.02 μg AAE/mg, 74.43 ± 0.04% and 67.34 ± 0.03%, respectively. Based on the bioactivities, the green synthesized FeNPs have potential for therapeutic applications.