Triterpenoids from <i>Uncaria rhynchophylla</i> and Their PTP1B Inhibitory Activity

Uncaria rhynchophylla (Gouteng) is a famous traditional Chinese medicine used for psychiatric and hypotensive purposes in China. In this study, the ethyl acetate (EtOAc) part of U. rhynchophylla was revealed with protein tyrosine phosphatase 1B (PTP1B) inhibitory activity. Subsequent investigation on the EtOAc part yielded one new triterpenoid, 3β-formyloxy-6β,19α-dihydroxyurs-12-en-28-oic acid (1) and four known ones, 3β,6β,19α-trihydroxyurs-12-en-28-oic acid (2), 2-oxopomolic acid (3), 3β,19α-dihydroxy-6-oxo-olean-12-en-28-oic acid (4) and sumaresinolic acid (5). The structure of compound 1 was determined by extensive HRESIMS, IR, 1D and 2D NMR spectroscopic analyses. Two ursane-type triterpenoids (2 and 3) showed selective inhibition on PTP1B with IC₅₀ values of 48.2 and 178.7 μM. The enzyme kinetic study suggested that compounds 2 and 3 were mix-type inhibitors on PTP1B with K_i values of 15.6 and 132.5 μM. This investigation manifests the antidiabetic potency of U. rhynchophylla with triterpenoids as the active constituents.     

Long non-coding RNA LINC00488 facilitates thyroid cancer cell progression through miR-376a-3p/PON2

Objective: Long non-coding RNAs (lncRNAs) recently have been identified as influential indicators in a variety of malignancies. The aim of the present study was to identify a functional lncRNA LINC00488 and its effects on thyroid cancer in the view of cell proliferation and apoptosis.Methods: In order to evaluate the effects of LINC00488 on the cellular process of thyroid cancer, we performed a series of in vitro experiments, including cell counting kit-8 (CCK-8) assay, EdU (5-ethynyl-2′-deoxyuridine) assay, flow cytometry, transwell chamber assay, Western blot and RT-qPCR. The target gene of LINC00488 was then identified by bioinformatics analysis (DIANA and TargetScan). Finally, a series of rescue experiments was conducted to validate the effect of LINC00488 and its target genes on proliferation, migration, invasion and apoptosis of thyroid cancer.Results: Our findings revealed that LINC00488 was highly expressed in thyroid cancer cell lines (BCPAP, BHP5-16, TPC-1 and CGTH-W3) and promoted the proliferation, migration and invasion, while inhibited the apoptosis of thyroid cancer cells (BCPAP and TPC-1). The results of bioinformatics analysis and dual luciferase reporter gene assay showed that LINC00488 could directly bind to miR-376a-3p and down-regulated the expression level of miR-376a-3p. In addition, Paraoxonase-2 (PON2) was a target gene of miR-376a-3p and negatively regulated by miR-376a-3p. Rescue experiment indicated that LINC00488 might enhance PON2 expression by sponging miR-376a-3p in thyroid cancer.Conclusion: Taken together, our study revealed that lncRNA LINC00488 acted as an oncogenic gene in the progression of thyroid cancer via regulating miR-376a-3p/PON2 axis, which indicated that LINC00488-miR-376a-3p-PON2 axis could serve as novel biomarkers or potential targets for the treatment of thyroid cancer.     

Gualou Xiebai Banxia decoction ameliorates Poloxamer 407-induced hyperlipidemia

Ethnopharmacological relevance: Gualou Xiebai Banxia (GLXBBX) decoction is a well-known traditional Chinese herbal formula that was first discussed in the Synopsis of the Golden Chamber by Zhang Zhongjing in the Eastern Han Dynasty. In traditional Chinese medicine, GLXBBX is commonly prescribed to treat cardiovascular diseases, such as coronary heart disease and atherosclerosis.Objective: The present study aimed to examine GLXBBX’s preventative capacity and elucidate the potential molecular mechanism of Poloxamer 407 (P407)-induced hyperlipidemia in rats.Materials and methods: Both the control and model groups received pure water, and the test group also received a GLXBBX decoction. For each administration, 3 ml of the solution was administered orally. To establish hyperlipidemia, a solution mixed with 0.25 g/kg P407 dissolved in 0.9% normal saline was injected slowly into the abdominal cavity. At the end of the study, the rats’ plasma lipid levels were calculated using an automatic biochemical analyzer to evaluate the preventative capability of the GLXBBX decoction, and the serum and liver of the rats were collected.Results: The GLXBBX decoction significantly improved P407-induced hyperlipidemia, including increased plasma triglycerides (TGs), aspartate aminotransferase (AST) elevation, and lipid accumulation. Moreover, GLXBBX decoction treatment increased lipoprotein lipase (LPL) activity and mRNA expression of LPL. Furthermore, GLXBBX significantly suppressed the mRNA expression of stearoyl-CoA desaturase (SCD1).Conclusion: GLXBBX significantly improved P407-induced hyperlipidemia, which may have been related to enhanced LPL activity, increased LPL mRNA expression, and decreased mRNA expression of SCD1.     

A previously uncharacterized two-component signaling system in uropathogenic Escherichia coli coordinates protection against host-derived oxidative stress with activation of hemolysin-mediated host cell pyroptosis

Uropathogenic Escherichia coli (UPEC) deploy an array of virulence factors to successfully establish urinary tract infections. Hemolysin is a pore-forming toxin, and its expression correlates with the severity of UPEC infection. Two-component signaling systems (TCSs) are a major mechanism by which bacteria sense environmental cues and respond by initiating adaptive responses. Here, we began this study by characterizing a novel TCS (C3564/C3565, herein renamed orhK/orhR for oxidative resistance and hemolysis kinase/regulator) that is encoded on a UPEC pathogenicity island, using bioinformatic and biochemical approaches. A prevalence analysis indicates that orhK/orhR is highly associated with the UPEC pathotype, and it rarely occurs in other E. coli pathotypes tested. We then demonstrated that OrhK/OrhR directly activates the expression of a putative methionine sulfoxide reductase system (C3566/C3567) and hemolysin (HlyA) in response to host-derived hydrogen peroxide (H₂O₂) exposure. OrhK/OrhR increases UPEC resistance to H₂O₂ in vitro and survival in macrophages in cell culture via C3566/C3567. Additionally, OrhK/OrhR mediates hemolysin-induced renal epithelial cell and macrophage death via a pyroptosis pathway. Reducing intracellular H₂O₂ production by a chemical inhibitor impaired OrhK/OrhR-mediated activation of c3566-c3567 and hlyA. We also uncovered that UPEC links the two key virulence traits by cotranscribing the c3566-c3567 and hlyCABD operons. Taken together, our data suggest a paradigm in which a signal transduction system coordinates both bacterial pathogen defensive and offensive traits in the presence of host-derived signals; and this exquisite mechanism likely contributes to hemolysin-induced severe pathological outcomes.     

Identification of three Zwittermicin A biosynthesis-related genes from <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> subsp. <Emphasis Type="Italic">kurstaki</Emphasis> strain YBT-1520

Zwittermicin A (ZwA) is a novel, broad-spectrum linear aminopolyol antibiotic produced by some Bacillus cereus and Bacillus thuringiensis. However, only part of its biosynthesis cluster has been identified and characterized from B. cereus UW85. To better understand the biosynthesis cluster of ZwA, a bacterial artificial chromosome (BAC) library of B. thuringiensis subsp. kurstaki strain YBT-1520, a ZwA-producing strain, was constructed. Two BAC clones, 1F8 and 5E2, were obtained by PCR, which overlap the known ZwA biosynthesis cluster of B. cereus UW85. This ZwA biosynthesis cluster is at least 38.6 kb and is located on the chromosome, instead of the plasmid. Partial DNA sequencing revealed both BAC clones carry three new ZwA biosynthesis-related genes, zwa6, zwa5A and zwa5B, which were found at the corresponding location of B. cereus UW85. Putative amino acid sequences of these genes shown that ZWA6 is homologous to a typical carbamoyltransferase from Streptomyces avermitilis, while ZWA5A and ZWA5B are homologs of cysteine synthetase and ornithine cyclodeaminase which jointly synthesize 2,3-diaminopropionate in the viomycin biosynthesis pathway, respectively. The identification of these three genes further supports the hypothesized ZwA biosynthesis pathway.     

Carbon : nitrogen stoichiometry in forest ecosystems during stand development

Aim Carbon (C) and nitrogen (N) stoichiometry is a critical indicator of biogeochemical coupling in terrestrial ecosystems. However, our current understanding of C : N stoichiometry is mainly derived from observations across space, and little is known about its dynamics through time. Location Global secondary forests. Methods We examined temporal variations in C : N ratios and scaling relationships between N and C for various ecosystem components (i.e. plant tissue, litter, forest floor and mineral soil) using data extracted from 39 chronosequences in forest ecosystems around the world. Results The C : N ratio in plant tissue, litter, forest floor and mineral soil exhibited large variation across various sequences, with an average of 145.8 ± 9.4 (mean ± SE), 49.9 ± 3.0, 38.2 ± 3.1 and 18.5 ± 0.9, respectively. In most sequences, the plant tissue C : N ratio increased significantly with stand age, while the C : N ratio in litter, forest floor and mineral soil remained relatively constant over the age sequence. N and C scaled isometrically (i.e. the slope of the relationship between log‐transformed N and C is not significantly different from 1.0) in litter, forest floor and mineral soil both within and across sequences, but not in plant tissue either within or across sequences. The C : N ratio was larger in coniferous forests than in broadleaf forests and in temperate forests than in tropical forests. In contrast, the N–C scaling slope did not reveal significant differences either between coniferous and broadleaf forests or between temperate and tropical forests. Main conclusions These results suggest that C and N become decoupled in plants but remain coupled in other ecosystem components during stand development.     

Prevalence and Molecular Characterization of Glucose-6-Phosphate Dehydrogenase Deficiency at the China-Myanmar Border

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked hereditary disease that predisposes red blood cells to oxidative damage. G6PD deficiency is particularly prevalent in historically malaria-endemic areas. Use of primaquine for malaria treatment may result in severe hemolysis in G6PD deficient patients. In this study, we systematically evaluated the prevalence of G6PD deficiency in the Kachin (Jingpo) ethnic group along the China-Myanmar border and determined the underlying G6PD genotypes. We surveyed G6PD deficiency in 1770 adult individuals (671 males and 1099 females) of the Kachin ethnicity using a G6PD fluorescent spot test. The overall prevalence of G6PD deficiency in the study population was 29.6% (523/1770), among which 27.9% and 30.6% were males and females, respectively. From these G6PD deficient samples, 198 unrelated individuals (147 females and 51 males) were selected for genotyping at 11 known G6PD single nucleotide polymorphisms (SNPs) in Southeast Asia (ten in exons and one in intron 11) using a multiplex SNaPshot assay. Mutations with known association to a deficient phenotype were detected in 43.9% (87/198) of cases, intronic and synonymous mutations were detected alone in 34.8% (69/198) cases and no mutation were found in 21.2% (42/198) cases. Five non-synonymous mutations, Mahidol 487G>A, Kaiping 1388G>A, Canton 1376G>T, Chinese 4 392G>T, and Viangchan 871G>A were detected. Of the 87 cases with known deficient mutations, the Mahidol variant was the most common (89.7%; 78/87), followed by the Kaiping (8.0%; 7/87) and the Viangchan (2.2%; 2/87) variants. The Canton and Chinese 4 variants were found in 1.1% of these 87 cases. Among them, two females carried the Mahidol/Viangchan and Mahidol/Kaiping double mutations, respectively. Interestingly, the silent SNPs 1311C>T and IVS11nt93T>C both occurred in the same 95 subjects with frequencies at 56.4% and 23.5% in tested females and males, respectively (P<0.05). It is noteworthy that 24 subjects carrying the Mahidol mutation and two carrying the Kaiping mutation also carried the 1311C>T/IVS11nt93T>C SNPs. Further studies are needed to determine the enzyme levels of the G6PD deficient people and presence of additional G6PD mutations in the study population.     

Novel aromatic inhibitors of influenza virus neuraminidase make selective interactions with conserved residues and water molecules in the active site.

The active site of type A or B influenza virus neuraminidase is composed of 11 conserved residues that directly interact with the substrate, sialic acid. An aromatic benzene ring has been used to replace the pyranose of sialic acid in our design of novel neuraminidase inhibitors. A bis(hydroxymethyl)pyrrolidinone ring was constructed in place of the N-acetyl group on the sialic acid. The hydroxymethyl groups replace two active site water molecules, which resulted in the high affinity of the nanomolar inhibitors. However, these inhibitors have greater potency for type A influenza virus than for type B influenza virus. To resolve the differences, we determined the X-ray crystal structure of three benzoic acid substituted inhibitors bound to the active site of B/Lee/40 neuraminidase. The investigation of a hydrophobic aliphatic group and a hydrophilic guanidino group on the aromatic inhibitors shows changes in the interaction with the active site residue Glu275. The results provide an explanation for the difference in efficacy of these inhibitors against types A and B viruses, even though the 11 active site residues of the neuraminidase are conserved.     

Overexpression of the mango MiCO gene delayed flowering time in transgenic Arabidopsis

Plant Cell, Tissue and Organ Culture (PCTOC) - CONSTANS (CO)/CONSTANS-like (COL) genes play an important role in the photoperiodic flowering pathway. However, the functional roles of the CO/COL...