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This article examines the metabolites and antioxidant activity of Smilax nantoensis, a species in the genus Smilax that is commonly used in Traditional Chinese Medicine. The study identified eleven compounds in the plant for the first time and tested their antioxidant abilities using three different assays. While most of the compounds did not show strong potential, three compounds exhibited strong antioxidative activity. The research was supported by the Ministry of Science and Technology, Taiwan, and the authors express gratitude to ENABLE project of National Chung Hsing University and Kasetsart University Joint Research Project. [Extracted from the article]

Abstract: New hybrid films were synthesized by Fe2+ doping into polyoxometalates acid (POMs)/polyacrylamide (PAM) system, and the effect of Fe2+ doping on microstructure and photochromic properties was studied via transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectra (UV–vis) and X-ray photoelectron spectroscopy (XPS). The shape of molybdenumphosphoric acid (PMoA) particles changed from well dispersed sphere to irregular conglomeration. The vibrational spectra of FT-IR verified that the hydrogen bonding between PMoA and PAM was weakened after Fe2+ doping. The hybrid films exhibited a good photochromic property, which changed from colorless to blue under UV irradiation. The color change intensity of PMoA/PAM film was 2.56times stronger than that of Fe2+/PMoA/PAM under the same condition. XPS results indicated that the amount of PMoA in photo-reductive reaction was decreased after Fe2+ doping, which resulted in the photochromic efficiencies weakened. [Copyright &y& Elsevier]

Arp2/3 complex is a key actin filament nucleator that assembles branched actin networks in response to cellular signals. The activity of Arp2/3 complex is regulated by both activating and inhibitory proteins. Coronins make up a large class of actin-binding proteins previously shown to inhibit Arp2/3 complex. Although coronins are known to play a role in controlling actin dynamics in diverse processes, including endocytosis and cell motility, the precise mechanism by which they regulate Arp2/3 complex is unclear. We conducted a detailed biochemical analysis of budding yeast coronin, Crn1, and found that it not only inhibits Arp2/3 complex but also activates it. We mapped regions required for activation and found that Crn1 contains a sequence called CA, which is conserved in WASp/Scar proteins, the prototypical activators of Arp2/3 complex. Point mutations in CA abolished activation of Arp2/3 complex by Crn1 in vitro. Confocal microscopy and quantitative actin patch tracking showed that these mutants had defective endocytic actin patch dynamics in Saccharomyces cerevisiae, indicating that activation of Arp2/3 complex by coronin is required for normal actin dynamics in vivo. The switch between the dual modes of regulation by Crn1 is controlled by concentration, and low concentrations of Crn1 enhance filament binding by Arp2/3 complex, whereas high concentrations block binding. Our data support a direct tethering recruitment model for activation of Arp2/3 complex by Crn1 and suggest that Crn1 indirectly inhibits Arp2/3 complex by blocking it from binding actin filaments. [ABSTRACT FROM AUTHOR]

Bacterial species within the Acinetobacter baumannii-calcoaceticus (Acb) complex are very similar and are difficult to discriminate. Misidentification of these species in human infection may lead to severe consequences in clinical settings. Therefore, it is important to accurately discriminate these pathogens within the Acb complex. Raman spectroscopy is a simple method that has been widely studied for bacterial identification with high similarities. In this study, we combined surfaced-enhanced Raman spectroscopy (SERS) with a set of machine learning algorithms for identifying species within the Acb complex. According to the results, the support vector machine (SVM) model achieved the best prediction accuracy at 98.33% with a fivefold cross-validation rate of 96.73%. Taken together, this study confirms that the SERS-SVM method provides a convenient way to discriminate between A. baumannii, Acinetobacter pittii, and Acinetobacter nosocomialis in the Acb complex, which shows an application potential for species identification of Acinetobacter baumannii-calcoaceticus complex in clinical settings in near future. [ABSTRACT FROM AUTHOR]

Serum-stimulation of quiescent mouse fibroblasts results in transcriptional activation of tissue factor (TF), the cellular initiator of blood coagulation. This requires the rapid entry of c-Fos into specific AP-1 DNA-binding complexes and can be strongly inhibited by the adenovirus E1A 12S gene product. In this study, we utilized a panel of E1A mutants deficient in cellular protein binding to analyse the molecular basis for E1A inhibition of a minimal, c-Fos-dependent TF promoter/reporter construct in mouse AKR-2B fibroblasts. Mutations which impaired binding of the retinoblastoma tumor suppressor protein family members pRB, p107, and p130 relieved E1A-mediated inhibition of transcription in response to serum-stimulation or c-Fos overexpression. Inhibition was restricted to the G0 to G1 transition, consistent with the specificity of E1A for hypophosphorylated forms of RB proteins. Although E1A mutants deficient in CBP/p300 binding retained the ability to inhibit TF transcription, deletion of the amino-terminal portion of the CBP/p300 interaction domain was required to permit rescue of TF promoter activity by coexpression of pRB. Moreover, ectopic p107 could effectively substitute for pRB in relieving E1A-mediated repression. In primary mouse embryo fibroblasts, activity of the minimal AP-1-dependent TF promoter was suppressed in Rb-/- cells compared to parallel Rb+/- and Rb+/+ transfectants. Ectopic expression of either pRB or p107 markedly enhanced TF promoter activity in Rb-/- fibroblasts. Collectively, these data imply that pRB and p107 can cooperate with c-Fos to activate TF gene transcription in fibroblasts and suggest a requirement for another, as yet unidentified, E1A-binding protein. Oncogene (2000) 19, 3352–3362 [ABSTRACT FROM AUTHOR]

Unlike the WASP family of Arp2/3 complex activators, WISH/DIP/SPIN90 (WDS) family proteins activate actin filament nucleation by the Arp2/3 complex without the need for a preformed actin filament. This allows WDS proteins to initiate branched actin network assembly by providing seed filaments that activate WASP‐bound Arp2/3 complex. Despite their important role in actin network initiation, it is unclear how WDS proteins drive the activating steps that require both WASP and pre‐existing actin filaments during WASP‐mediated nucleation. Here, we show that SPIN90 folds into an armadillo repeat domain that binds a surface of Arp2/3 complex distinct from the two WASP sites, straddling a hinge point that may stimulate movement of the Arp2 subunit into the activated short‐pitch conformation. SPIN90 binds a surface on Arp2/3 complex that overlaps with actin filament binding, explaining how it could stimulate the same structural rearrangements in the complex as pre‐existing actin filaments. By revealing how WDS proteins activate the Arp2/3 complex, these data provide a molecular foundation to understand initiation of dendritic actin networks and regulation of Arp2/3 complex by its activators. Synopsis: Unlike WASP, WDS proteins do not need a pre‐existing actin filament to activate new filament nucleation by the Arp2/3 complex and can therefore trigger the assembly of branched actin networks. A new crystal structure of WDS protein SPIN190 in complex with Arp2/3 sheds light on the underlying mechanism. We solved the crystal structure of the Arp2/3 complex activator SPIN90 alone and bound to the complex.Unlike the canonical activator WASP, SPIN90 activates the Arp2/3 complex without requiring a preformed filament.SPIN90 binds a putative hinge region that may rotate Arp2 into a short pitch helical conformation, explaining how it could stimulate the same activating structural change as WASP.The SPIN90 binding site overlaps with the binding site for actin filaments, providing a mechanism for it to induce the same activating conformational changes as filaments. New crystal structures reveal how WDS proteins facilitate Arp2/3‐dependent actin filament nucleation in the absence of pre‐existing filaments. [ABSTRACT FROM AUTHOR]

Summary: Background: Arp2/3 complex is a key actin cytoskeletal regulator that creates branched actin filament networks in response to cellular signals. WASP-activated Arp2/3 complex assembles branched actin networks by nucleating new filaments from the sides of pre-existing ones. WASP-mediated activation requires seed filaments, to which the WASP-bound Arp2/3 complex can bind to form branches, but the source of the first substrate filaments for branching is unknown. Results: Here we show that Dip1, a member of the WISH/DIP/SPIN90 family of actin regulators, potently activates Arp2/3 complex without preformed filaments. Unlike other Arp2/3 complex activators, Dip1 does not bind actin monomers or filaments, and it interacts with the complex using a non-WASP-like binding mode. In addition, Dip1-activated Arp2/3 complex creates linear instead of branched actin filament networks. Conclusions: Our data show the mechanism by which Dip1 and other WISH/DIP/SPIN90 proteins can provide seed filaments to Arp2/3 complex to serve as master switches in initiating branched actin assembly. This mechanism is distinct from other known activators of Arp2/3 complex. [ABSTRACT FROM AUTHOR]

Highlights: [•] pH had an effect on the microstructure and photochromic properties of composite films. [•] The intensity of absorbance was decreased with increase of pH after UV irradiated. [•] Responsiveness was related to microstructure’s change generated by different pH. [ABSTRACT FROM AUTHOR]