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Background: The transcriptome of the fruit pulp of the sweet orange variety Anliu (WT) and that of its red fleshed mutant Hong Anliu (MT) were compared to understand the dynamics and differential expression of genes expressed during fruit development and ripening. Results: The transcriptomes of WT and MT were sampled at four developmental stages using an Illumina sequencing platform. A total of 19,440 and 18,829 genes were detected in MT and WT, respectively. Hierarchical clustering analysis revealed 24 expression patterns for the set of all genes detected, of which 20 were in common between MT and WT. Over 89% of the genes showed differential expression during fruit development and ripening in the WT. Functional categorization of the differentially expressed genes revealed that cell wall biosynthesis, carbohydrate and citric acid metabolism, carotenoid metabolism, and the response to stress were the most differentially regulated processes occurring during fruit development and ripening. Conclusion: A description of the transcriptomic changes occurring during fruit development and ripening was obtained in sweet orange, along with a dynamic view of the gene expression differences between the wild type and a red fleshed mutant. [ABSTRACT FROM AUTHOR]

Reports that the dissolution of PtO2 in concentrated H2SO4 under an atmosphere of CO results in the formation of hexacarbonyldiplatinum(I), [(Pt(CO)3)2]2+. First homoleptic, dinuclear, cationic platinum carbonyl complex; Complete characterization by nuclear magnetic resonance spectroscopy; Geometric optimization of the compound by density functional calculations.

Reports on a facile route for the preparation of the rhodium(I) tetracarbonyl cation, [Rh(CO)4]+, from the neutral Rh carbonyl cluster, Rh4(CO)12, in concentrated H2SO4 solution under a CO atmosphere. First example of the oxidation of Rh(0) to Rh(I) by H+; Action of the Rh(I) tetracarbonyl cation to catalyze the carbonylation of the olefins.

Polymethoxyflavones (PMFs) are a class of abundant specialized metabolites with remarkable anticancer properties in citrus. Multiple methoxy groups in PMFs are derived from methylation modification catalyzed by a series of hydroxylases and O-methyltransferases (OMTs). However, the specific OMTs that catalyze the systematic O-methylation of hydroxyflavones remain largely unknown. Here, we report that PMFs are highly accumulated in wild mandarins and mandarin-derived accessions, while undetectable in early-diverging citrus species and related species. Our results demonstrated that three homologous genes, CreOMT3, CreOMT4, and CreOMT5, are crucial for PMF biosynthesis in citrus, and their encoded methyltransferases exhibit multisite O-methylation activities for hydroxyflavones, producing seven PMFs in vitro and in vivo. Comparative genomic and syntenic analyses indicated that the tandem CreOMT3, CreOMT4, and CreOMT5 may be duplicated from CreOMT6 and contributes to the genetic basis of PMF biosynthesis in the mandarin group through neofunctionalization. We also demonstrated that N17 in CreOMT4 is an essential amino acid residue for C3-, C5-, C6-, and C3'-O-methylation activity and provided a rationale for the functional deficiency of OMT6 to produce PMFs in early-diverging citrus and some domesticated citrus species. A 1,041-bp deletion in the CreOMT4 promoter, which is found in most modern cultivated mandarins, has reduced the PMF content relative to that in wild and early-admixture mandarins. This study provides a framework for reconstructing PMF biosynthetic pathways, which may facilitate the breeding of citrus fruits with enhanced health benefits. [ABSTRACT FROM AUTHOR]

Secretory structures in terrestrial plants serve as reservoirs for a variety of secondary metabolites. Among these, the secretory cavity of the Rutaceae family is notable for containing essential oils with a wide range of applications. However, the molecular basis underlying secretory cavity development is unknown. Here, we reveal a molecular framework for Citrus oil gland formation. Using genetic mapping and genome editing, we demonstrated that this process requires LATE MERISTEM IDENTITY1 (LMI1), a key regulator of leaf serration. A conserved GCC box element of the LMI1 promoter recruits DORNROSCHEN-like (DRNL) for transcriptional activation. This DRNL-LMI1 cascade triggers MYC5 activation, facilitating the development of oil glands and the biosynthesis of essential oils. Our findings spotlight cis-regulatory divergence within leaf shape genes, propelling novel functional tissue formation. [ABSTRACT FROM AUTHOR]

Examines the synthesis and photochromism of spirobenzopyrans and spirobenzothiapyran derivatives with metal ions. Inhibition of selective binding ability by spirobenzopyrans; Type of metal ion facilitating the photoisomerization to the merocyanine form; Observation of shifts in the absorption spectra of certain metal ions.

Two novel enediyne-derived natural products, amycolamycins A and B (1 and 2), were characterized from a locust-associated actinomycete Amycolatopsis sp. HCa4. Amycolamycins A and B contain a unique 2-(cyclopenta[a]inden-5-yl)oxirane core with suspected enediyne polyketide biosynthetic origin. Sequencing and analysis of the acm biosynthetic gene cluster allowed us to propose the biosynthetic pathway of 1 and 2. Moreover, amycolamycin A (1) was selectively cytotoxic to the M231 breast cancer cell line. [ABSTRACT FROM AUTHOR]

Microbial constructions of secondary metabolites are generally biosynthetic gene cluster (BGC)-based, and the forging of different BGC-sourced intermediates tends to be overlooked. Here, we show that the dalesconol bioassembly lines in Daldinia eschscholzii can sequester guest intermediates (i.e., building blocks produced outside the dalesconol biosynthetic gene cluster) to form arrays of skeletally undescribed molecules such as (+)-dalescone A, a potent inhibitor against the NLRP3 inflammasome activation. [ABSTRACT FROM AUTHOR]

Autoimmune and inflammatory diseases are associated with inappropriate activation of the NOD-like receptor protein 3 (NLRP3) inflammasome, but suitable inhibitors against such improper activations remain scarce. Here, spirodalesol (1) from Daldinia eschscholzii was structurally characterized and is biosynthetically proposed as an NLRP3 inflammasome activation inhibitor with an unprecedented carbon skeleton. [ABSTRACT FROM AUTHOR]

The Pictet-Spengler (PS) reaction constructs plant alkaloids such as morphine and camptothecin, but it has not yet been noticed in the fungal kingdom. Here, a silent fungal Pictet-Spenglerase (FPS) gene of Chaetomium globosum 1C51 residing in Epinephelus drummondhayi guts is described and ascertained to be activable by 1-methyl-L-tryptophan (1-MT). The activated FPS expression enables the PS reaction between 1-MT and flavipin (fungal aldehyde) to form "unnatural" natural products with unprecedented skeletons, of which chaetoglines B and F are potently antibacterial with the latter inhibiting acetylcholinesterase. A gene-implied enzyme inhibition (GIEI) strategy has been introduced to address the key steps for PS product diversifications. In aggregation, the work designs and validates an innovative approach that can activate the PS reaction-based fungal biosynthetic machinery to produce unpredictable compounds of unusual and novel structure valuable for new biology and biomedicine. [ABSTRACT FROM AUTHOR]

Reports on the synthesis of a series of oxo complexes with formula Re(O)X(diyne) (X = I, Me, Et), from 2,7-nonadiyne and Re(O)I[sub 3]-PPh[sub 3)[sub 2]. Oxo ligand coordination to boron; Protonation of Re(O)X(2-butyne)[sub 2] and Re(O)(X)(2,7-nonadiyne)[sub 2] with a variety of acids and resulting compounds; Protonation kinetics; Conformations.