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Introduction: CIP, a broad-spectrum antibiotic, is crucial for managing bacterial infections. Its efficacy relies on maintaining high-quality standards, which can be affected by manufacturing, regulatory oversight and storage practices. This study compares the quality of CIP preparations in Vietnam and Nigeria, two nations with contrasting regulatory frameworks, to assess compliance with pharmaceutical standards and identify risks from substandard or falsified medicines.Methods: A total of 46 CIP preparations were analysed, 20 purchased from 13 vendors in Vietnam and 26 from 13 vendors in Nigeria. Data on vendor qualifications and storage conditions were collected. Antibacterial activity was tested using a modified disk diffusion assay, and content and purity were evaluated via reversed-phase HPLC.Results: Vietnam\'s drug outlets showed stricter regulation, with 100% registration and 61.5% staffed by Bachelor of Pharmacy holders, compared with only 23.1% in Nigeria. Temperature and humidity monitoring was universal in Vietnam but minimal in Nigeria (23.1% and 15.4%, respectively). Antimicrobial testing confirmed effectiveness for all but one sample (Vietnam), while Nigerian samples had greater variability. Reversed-phase HPLC revealed seven Nigerian samples (26.9%) with
Publications
Plant architecture is a key determinant of crop yield, and understanding the genetic basis of its regulation is crucial for crop improvement. BLADE-ON-PETIOLE (BOP) genes are known to play a fundamental role in shaping plant architecture across diverse species. In this study, we demonstrate pleiotropic effects of the barley BOP gene Uniculme4 (Cul4) on various aspects of plant architecture, including plant height, culm diameter, and grain traits. Accordingly, Cul4 is broadly expressed in different tissues and developmental stages. Comparing transcriptome profiles of cul4 mutant and wild-type plants, we uncover a novel link between Cul4 and the jasmonic acid (JA) biosynthetic pathway. Our findings demonstrate that proper Cul4 function is required to repress JA biosynthesis, with cul4 mutants exhibiting increased levels of JA and its precursor 12-oxo-phytodienoic acid. Up-regulation of WRKY and bHLH transcription factors shows JA signalling is also impacted by Cul4. Additionally, our study sheds light on the role of Cul4 in flowering time regulation, potentially through its interaction with florigen-like genes. This research enhances our understanding of the mechanisms and pathways acting downstream of BOP genes.
Publications
A novel series of profluorescent rhodamine nitroxide conjugates are synthesized utilizing well‐known isonitrile‐based multicomponent reactions (IMCRs). The synthesized conjugates are rationally designed as mitochondria‐targeting probes for the detection of reactive oxygen species in living cells. Herein, the synthesized probes demonstrate high selectivity to target the mitochondria of both of PC3‐ and NIH3T3‐cells which represent cancer and normal cell lines. Attaching TEMPO nitroxide to rhodamine leads to fluorescence quenching, allowing for ROS detection and quantification. The prepared sensors provide a reliable method for distinguishing between different oxidative environments in living organisms through different levels of fluorescence to be measured. The use of the Ugi multicomponent reaction enables an efficient and versatile synthetic approach, offering significant advantages over previously reported methods for constructing ROS‐detecting probes. The simplicity of the reaction setup and the ability to generate a diverse library of products by varying Ugi components make this protocol highly adaptable for further chemical modification and potential applications in biological systems.
Publications
Leptomonines A and B, two novel rare benzyltetrahydroisoquinoline N-oxides, were isolated from the aerial parts of Leptopyrum fumarioides (L.) Reichenb. collected in Tuv province, Mongolia. Their chemical structures, absolute configurations, and conformations were established by 2D-NMR and CD spectral analyses. Leptomonine A (1) can suppress TNF-α production and COX-2 expression in LPS-stimulated RAW 267.4 cells. This compound at a concentration of 100 μM significantly reduced the TNF-α and COX-2 levels by 36.43% and 47.10%, respectively, compared with the negative control. Moreover, leptomonine B (2) remarkably lowers COX-2 levels at the highest concentration. The docking simulations were conducted with the COX-2 enzyme and revealed the binding ability of leptomonine A (1) and leptomonine B (2) with binding energies of − 9.03 and − 8.96 kcal/mol, respectively. The interactions of these alkaloids with the targets were mainly with the hydrophobic and hydrophilic sites, which are quite similar to rofecoxib. Phytochemical investigation revealed the diversity and novelty of the natural isoquinoline alkaloids in Leptopyrum fumarioides. Two new benzyltetrahydroisoquinoline N-oxides were identified as the bioactive constituents of Leptopyrum fumarioides by assessing its anti-inflammatory effects. The findings provide scientific justification to support the traditional application of Leptopyrum fumarioides for treating liver diseases associated with inflammation.
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Jasmonates (JAs) are a family of oxylipin phytohormones regulating plant development and growth and mediating ‘defense versus growth’ responses. The upstream JA biosynthetic precursor cis-(+)-12-oxo-phytodienoic acid (cis-OPDA) acts independently of CORONATIVE INSENSITIVE 1 (COI1)-mediated JA signaling in several stress-induced and developmental processes. However, its perception and metabolism are only partially understood. A few years ago, a low abundant isoleucine analog of the biologically active JA-Ile, OPDA-Ile, was detected years ago in wounded leaves of flowering plants, opening up the possibility that conjugation of cis-OPDA to amino acids might be a relevant mechanism for cis-OPDA regulation. Here, we extended the analysis of amino acid conjugates of cis-OPDA and identified naturally occurring OPDA-Val, OPDA-Phe, OPDA-Ala, OPDA-Glu, and OPDA-Asp accumulating in response to biotic and abiotic stress in Arabidopsis (Arabidopsis thaliana). The OPDA-amino acid conjugates displayed cis-OPDA-related plant responses in a JA-Ile-dependent manner. We also showed that the synthesis and hydrolysis of cis-OPDA amino acid conjugates are mediated by members of the amidosynthetase GRETCHEN HAGEN 3 (GH3) and the amidohydrolase INDOLE-3-ACETYL-LEUCINE RESISTANT 1 (ILR1)/ILR1-like (ILL) families. Thus, OPDA amino acid conjugates function in the catabolism or temporary storage of cis-OPDA in stress responses instead of acting as chemical signals per se.
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Bitter taste perception cautions humans against the ingestion of potentially toxic compounds. However, current knowledge about natural bitter substances and their activation of human bitter taste receptors (TAS2Rs) is biased toward substances from flowering plants, whereas other sources are underrepresented. Although numerous mushrooms taste bitter, the corresponding substances and receptors are unexplored. Three previously undescribed triterpene glucosides, named oligoporins D−F, together with the known oligoporins A and B, were isolated from Amaropostia stiptica. The structures of oligoporins D−F were determined using spectroscopic analyses. The isolated oligoporins and the bitter indolalkaloid infractopicrin from Cortinarius infractus were functionally screened with all TAS2Rs. For all compounds, at least one responding receptor was identified. Oligoporin D activated TAS2R46 already at a submicromolar concentration and thus belongs to the family of most potent bitter agonists. The addition of mushroom compounds to the list of cognate TAS2R activators lowers the existing bias of knowledge about bitter agonists.
Publications
The ability to chemoselectively modify either the peptide backbone or specific side chains is critical to advance the fields of bioconjugation and peptide pharmaceuticals. Transition-metal catalysis has been widely used in peptide and protein derivatization but mostly under homogeneous conditions. Herein, we present a first-in-class heterogeneous catalytic approach for the site-selective functionalization of histidinecontaining peptides with aryl and alkenyl moieties bearing fluorescent and affinity tags, lipids, and conjugation handles. This heterogeneous derivatization strategy employs a copper(II) hexacyanometallate to catalyze the Chan−Lam reaction with boronic acids at either the backbone or the histidine imidazole, thus providing novel results that differ from those previously reported for the homogeneous Cu(OAc)2-mediated coupling procedure. A correlation was established between the structural and electronic properties of the copper(II) hexacyanometalate with its ability to catalyze this oxidative cross-coupling. This report expands the toolbox for latestage peptide derivatization and labeling by unlocking the reactivity of the histidine side chain rather than merely acting as a directing group, thus boosting applications of heterogeneous catalysis in drug discovery and development.
Publications
Fruit pigmentation is a major signal that attracts frugivores to enable seed dispersal. In most fleshy fruit, green chlorophyll typically accumulates early in development and is replaced by a range of pigments during ripening. In species such as grape and strawberry, chlorophyll is replaced by red anthocyanins produced by the flavonoid biosynthetic pathway. Eggplant (Solanum melongena) is unique, as its fruit accumulates anthocyanins beginning from fruit set, and these are later replaced by the yellow flavonoid-pathway intermediate naringenin chalcone. To decipher the genetic regulation of this extraordinary pigmentation shift, we integrated mRNA and microRNA (miRNA) profiling data obtained from developing eggplant fruit. We discovered that SQUAMOSA PROMOTER BINDING-LIKE (i.e., SPL6a, SPL10, and SPL15), MYB1, and MYB2 transcription factors (TFs) regulate anthocyanin biosynthesis in early fruit development, whereas the MYB12 TF controls later accumulation of naringenin chalcone. We further show that miRNA157 and miRNA858 negatively regulate the expression of SPLs and MYB12, respectively. Taken together, our findings suggest that opposing and complementary expression of miRNAs and TFs controls the pigmentation switch in eggplant fruit skin. Intriguingly, despite the distinctive pigmentation pattern in eggplant, fruit development in other species makes use of homologous regulatory factors to control the temporal and spatial production of different pigment classes.