Applied Biological Chemistry最新文献

This study aimed to meticulously assess the effectiveness of hyaluronic acid (HA) in mitigating symptoms associated with monosodium iodoacetate (MIA)-induced osteoarthritis (OA) symptoms in rodent models and to investigate the underlying mechanistic pathways. Eight-week-old rats were randomly allocated to a normal control group and three experimental groups (n = 10 per group). The normal group did not undergo any treatment. The experimental groups were administered MIA for 1 week to induce osteoarthritis, and orally administered distilled water (control group), 2 mg/kg indomethacin (INDO group), or 20 mg/kg HA (HA20 group) daily for 4 weeks. The HA20 group showed a significant improvement in hind-paw weight-bearing distribution after 4 weeks compared to the control group. HA suppressed inflammatory responses by reducing the overproduction of prostaglandin E2 and leukotriene B4 and protected the vital components of the articular ECM, including glycosaminoglycans and aggrecan. HA treatment effectively reduced inflammation, protected cartilage by inhibiting MMP expression, and suppressed inflammatory mediator production. This study demonstrates that HA has potential to alleviate OA symptoms in a rodent model stimulated with MIA, rendering it a promising therapeutic agent for OA.

Phytophthora infestans (P. infestans) is a highly destructive oomycete that causes the late blight in Solanaceous crops, such as potatoes and tomatoes, reducing crop yield. Although many pesticides are used to control P. infestans, the pathogen has evolved resistance to these chemical pesticides over time. In this study, we employed RNAi technology as an alternative strategy to suppress P. infestans infection. We designed and synthesized two dsRNAs targeting 5' and 3' regions of the Avirulence Protein 3a (Avr3a) gene, a key effector essential for the virulence of P. infestans. Interestingly, the dsRNA targeting the 5' region which contains the conserved RxLR-EER motif of Avr3a exhibited more substantial suppression of P. infestans infection and Avr3a expression level compared to the 3' region targeting dsRNA. Additionally, we identified changes in the expression of genes related to pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) in plants treated with these dsRNAs. In leaves treated with dsRNAs targeting Avr3a, the expression of PTI-related genes was restored, while ETI-related genes showed lower expression levels compared to the mock-treated leaves. These results suggest that dsRNAs targeting Avr3a effectively suppress P. infestans infection, enabling plants to achieve balanced immunity and enhanced defense.

Inflammation, diabetes, and even malignancies are pharmacological effects connected by antioxidant capacity and free radicals. Many antioxidants scavenge free radicals originating from dietary sources such as fruits, vegetables, and teas. To identify the bioactive components of Ligularia stenocephala, an effective method combining HPLC-QTOF-MS and bioactivity evaluation was investigated for the first time. Antioxidant agents were isolated from L. stenocephala, a folk medicine used for edema and scrofula in Korea, Japan, and China. The phytochemical investigation of the aerial parts of L. stenocephala resulted in the separation and determination of six compounds (1–6). In particular, the chemical structures were identified as hyperoside (1), 3,5-dicaffeoylquinic acid (2), 3,5-dicaffeoylquinic acid methyl ester (3), trifolin (4), rutin (5), and 3,4-dicaffeoylquinic acid (6). Their structures were identified using 1D and 2D NMR spectroscopy and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) data analysis. The results showed that phenolic components were responsible for the antioxidant inhibitory activity of L. stenocephala. Additionally, to understand the mechanisms of the antioxidant inhibitory activity of L. stenocephala, a docking simulation study was performed to support the in vitro results. Taken together, this new method is rapid, inexpensive, and can be applied to identify the active components of medicinal herbs without separation.

In bacteria and archaea, CRISPRs and Cas proteins constitute an adaptive immune system against invading foreign genetic materials, such as bacteriophages and plasmids. To counteract CRISPR-mediated immunity, bacteriophages encode anti-CRISPR (Acr) proteins that neutralize the host CRISPR–Cas systems. Several Acr proteins that act against type I-E CRISPR–Cas systems have been identified. Here, we describe the biochemical characterization of two type I-E Acr proteins, AcrIE2 and AcrIE4. We determined the crystal structure of AcrIE2 using single-wavelength anomalous diffraction and performed a structural comparison with the previously reported AcrIE2 structures solved by different techniques. Binding assays with type I-E Cas proteins were carried out for the target identification of AcrIE2. We also analyzed the interaction between AcrIE4 and its target Cas component using biochemical methods. Our findings corroborate and expand the knowledge on type I-E Acr proteins, illuminating diverse molecular mechanisms of inhibiting CRISPR-mediated prokaryotic anti-phage defense.

Dangkwisoo-san (DS) is a traditional Korean herbal medicine used to treat traumatic diseases, including pulmonary contusions, traumatic pneumothorax, bruising, and ankle sprain. Quality control (QC) biomarkers for DS can help ensure its safety and efficacy. Although chemical quality assessments are performed to ensure consistent efficacy of DS, the identity and quantity of the compounds contained within a given natural product is a frequent complication. We conducted a literature review to identify biological assays that support the chemical QC of DS. The results of our investigation confirmed that in vitro experiments with aqueous and alcoholic extracts of DS exhibited positive effects on many aspects of treatment. With 80% EtOH extraction, a low concentration of DS (1 μg/ml) significantly diminished the expression of inflammatory factors, such as nitric oxide (NO), TNF-α, IL-1β, and IL-6, in the Raw264.7 cell line. MeOH extracts activated NRF2 and antioxidant activities in response to the inflammatory inducer LPS, and water extracts of DS remarkably reduced proinflammatory cytokine levels compared to dexamethasone and cyclosporin treatments. Aqueous extracts of DS at a moderate dose of 125 μg/ml supported bone regeneration, recovered ischemic injury in an eNOS-dependent manner, and prevented metabolic disorders (TRPM7 channel inhibition). Cytokines, NO, and immunoglobulins are potential biological QC biomarkers to assess the anti-inflammation and immune response to DS. Future quality evaluation studies of herbal medicines (herbal prescriptions) should aim to select the mechanism-based in vitro efficacy evaluation methods that can estimate consistent clinical effects.

A natural product library consisting of the culture extracts of 814 actinomycete strains was screened for antifungal compounds that disrupt the cell integrity of plant pathogenic fungi using an adenylate kinase (AK) assay system. The culture extract of Streptomyces xanthocidicus strain S3 exhibited high AK activity against various plant pathogens. The active ingredients, AT-1 and AT-2, were isolated from the culture extract using a series of chromatographic procedures. Based on MS, UV, and NMR spectrometric analyses, the structures of AT-1 and AT-2 were determined as the pentaene macrolides, AB023a and takanawaene C. AB023a and takanawaene C displayed broad-spectrum antifungal activity against Aspergillus oryzae, Botrytis cinerea, Colletotrichum coccodes, C. gloeosporioides, C. orbiculare, Cylindrocarpon destructans, and Fusarium oxysporum f. sp. lycopersici, showing minimum inhibitory concentrations of 1–32 μg/mL. Treatment of AB023a and takanawaene C successfully inhibited anthracnose development on pepper plants in a concentration-dependent manner without phytotoxicity. The disease control efficacy of both compounds was comparable to that of the commercial fungicide chlorothalonil. Collectively, these results suggest that the polyene macrolides produced by S. xanthocidicus strain S3 can be used as natural fungicides for plant disease control.