Alkaloids of NIRAM,natural dye from Polygonum tinctorium,and their anti-inflammatory activities

Phytochemical investigation of EtOH extract of NIRAM, natural dye from Polygonum tinctorium, resulted in the purification of nine alkaloid compounds (1–9) including four new compounds (1–4). Structures of these new compounds were elucidated by 1D and 2D NMR (¹H and ¹³C NMR, ¹H–¹H COSY, ¹H–¹³C HSQC, ¹H–¹³C HMBC), IR, UV, HR-ESI-MS, and ECD spectra. Isolated compounds (1–9) were tested for their inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated BV-2 cells. Compounds 1–3, 5, and 7 showed potent NO production inhibitory activities, with IC₅₀ values of 3.88–22.87 μM.     

Isolation of indole alkaloid and anthranilic acid derivatives from Indigo Pulverata Levis

A new indole alkaloid, pulveratinol (1), and two new anthranilic acid derivatives (2 and 3) were isolated from Indigo Pulverata Levis, together with 12 known compounds (4–15). The structures of the new compounds (1–3) were determined through spectroscopic methods. The absolute configuration of 1 was confirmed further by electronic circular dichroism (ECD) data analysis and computational method with advanced statistics (DP4). All isolated compounds (1–15) were evaluated for their potential neuroprotective effects through induction of nerve growth factor (NGF) in C6 glioma cells.     

A Molecular Chameleon for Mapping Subcellular Polarity in an Unfolded Proteome Environment

Environmental polarity is an important factor that drives biomolecular interactions to regulate cell function. Herein, a general method of using the fluorogenic probe NTPAN‐MI is reported to quantify the subcellular polarity change in response to protein unfolding. NTPAN‐MI fluorescence is selectively activated upon labeling unfolded proteins with exposed thiols, thereby reporting on the extent of proteostasis. NTPAN‐MI also reveals the collapse of the host proteome caused by influenza A virus infection. The emission profile of NTPAN‐MI contains information of the local polarity of the unfolded proteome, which can be resolved through spectral phasor analysis. Under stress conditions that disrupt different checkpoints of protein quality control, distinct patterns of dielectric constant distribution in the cytoplasm can be observed. However, in the nucleus, the unfolded proteome was found to experience a more hydrophilic environment across all the stress conditions, indicating the central role of nucleus in the stress response process.     

Precise extraction of the induced polarization in the 4He(e,e'p)3H reaction

We measured with unprecedented precision the induced polarization P(y) in (4)He(e,e'p)(3)H at Q(2)=0.8 and 1.3 (GeV/c)(2). The induced polarization is indicative of reaction-mechanism effects beyond the impulse approximation. Our results are in agreement with a relativistic distorted-wave impulse approximation calculation but are overestimated by a calculation with strong charge-exchange effects. Our data are used to constrain the strength of the spin-independent charge-exchange term in the latter calculation.     

Styrene Aziridination by Iron(IV) Nitrides

Thermolysis of the iron(IV) nitride complex [PhB(tBuIm)₃Fe?N] with styrene leads to formation of the high‐spin iron(II) aziridino complex [PhB(tBuIm)₃Fe‐N(CH₂CHPh)]. Similar aziridination occurs with both electron‐rich and electron‐poor styrenes, while bulky styrenes hinder the reaction. The aziridino complex [PhB(tBuIm)₃Fe‐N(CH₂CHPh)] acts as a nitride synthon, reacting with electron‐poor styrenes to generate their corresponding aziridino complexes, that is, aziridine cross‐metathesis. Reaction of [PhB(tBuIm)₃Fe‐N(CH₂CHPh)] with Me₃SiCl releases the N‐functionalized aziridine Me₃SiN(CH₂CHPh) while simultaneously generating [PhB(tBuIm)₃FeCl]. This closes a synthetic cycle for styrene azirdination by a nitride complex. While the less hindered iron(IV) nitride complex [PhB(MesIm)₃Fe?N] reacts with styrenes below room temperature, only bulky styrenes lead to tractable aziridino products.     

One‐dimensional growth of colloidal PbSe nanorods in chloroalkanes

Catalyst‐free, one‐pot synthesis of colloidal PbSe nanorods is demonstrated. The co‐solvent chloroalkanes play a critical role in driving a one‐dimensional growth of PbSe nanorods. The formation of the nanorod is likely governed by the anisotropic growth of the crystal due to the different reactivity of the facets. The photoluminescence quantum yield of the nanorods is above 25%, indicating well‐passivated surfaces. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Amyloid Cross-Seeding: Mechanism,Implication, and Inhibition

Most neurodegenerative diseases such as Alzheimer’s disease, type 2 diabetes, Parkinson’s disease, etc. are caused by inclusions and plaques containing misfolded protein aggregates. These protein aggregates are essentially formed by the interactions of either the same (homologous) or different (heterologous) sequences. Several experimental pieces of evidence have revealed the presence of cross-seeding in amyloid proteins, which results in a multicomponent assembly; however, the molecular and structural details remain less explored. Here, we discuss the amyloid proteins and the cross-seeding phenomena in detail. Data suggest that targeting the common epitope of the interacting amyloid proteins may be a better therapeutic option than targeting only one species. We also examine the dual inhibitors that target the amyloid proteins participating in the cross-seeding events. The future scopes and major challenges in understanding the mechanism and developing therapeutics are also considered. Detailed knowledge of the amyloid cross-seeding will stimulate further research in the practical aspects and better designing anti-amyloid therapeutics.     

Clustering and classification via cluster-weighted factor analyzers

In model-based clustering and classification, the cluster-weighted model is a convenient approach when the random vector of interest is constituted by a response variable $Y$ and by a vector ${\varvec{X}}$ of $p$ covariates. However, its applicability may be limited when $p$ is high. To overcome this problem, this paper assumes a latent factor structure for ${\varvec{X}}$ in each mixture component, under Gaussian assumptions. This leads to the cluster-weighted factor analyzers (CWFA) model. By imposing constraints on the variance of $Y$ and the covariance matrix of ${\varvec{X}}$ , a novel family of sixteen CWFA models is introduced for model-based clustering and classification. The alternating expectation-conditional maximization algorithm, for maximum likelihood estimation of the parameters of all models in the family, is described; to initialize the algorithm, a 5-step hierarchical procedure is proposed, which uses the nested structures of the models within the family and thus guarantees the natural ranking among the sixteen likelihoods. Artificial and real data show that these models have very good clustering and classification performance and that the algorithm is able to recover the parameters very well.     

Carbocyclization by radical closure onto O-trityl oximes: dramatic effect of diphenyl diselenide

O-Trityl oximes of 5- and 6-iodoaldehydes undergo radical cyclization to produce oximes when treated in refluxing tetrahydrofuran (THF) with Bu3SnH, 1,1'-azobis(cyclohexanecarbonitrile), i-Pr2NEt, and diphenyl diselenide (PhSeSePh).