Natural products from Pluchea sagittalis act as inhibitors of photosynthesis in vitro

Four compounds were isolated from roots and aerial parts of Pluchea sagittalis (Asteraceae), 3, 5-dihydroxy-6, 7, 3′, 4′-tetramethoxiflavunol (1), 5-hydroxymethylfurfural (2), 3, 4-dimethoxybenzaldehyde (3) and 2, 3, 4-trihydroxybenzaldeyde (4). Their herbicidal potential was detected by polarographic techniques. All of them inhibited the non-cyclic electron transport on basal, phosphorylating and uncoupled conditions from H₂O to methylviologen (MV); thus, they act as Hill reaction inhibitors. Studies on fluorescence of chlorophyll a (ChL a) indicated they have different modes of interaction and inhibition sites on the photosystem II electron transport chain; 1–3 have interacted with the acceptor side while 4 has interacted at the donor side.     

Effect of the structure of latex particles on adhesion. Part II: Analogy between peel adhesion and rheological properties of acrylic copolymers

This article, the second part of this series, concerns the development of an analogy between the peel behavior of pressure-sensitive adhesives and the dynamic mechanical properties of the corresponding copolymers. The adhesive copolymers used were synthesized by emulsion polymerization processes. Their physical and dynamic mechanical properties were characterized and presented in Part I of this series. In this study, an analogy was built up between the force in a peel test as a function of peel velocity, F_p(v_p), and the loss modulus of the adhesive as a function of the angular frequency in a dynamic mechanical experiment, G″(ω). This was done by superimposing the curves of F_p versus v_p and those of G″ versus ωβ₀/β, where β₀/β is a shift factor with β being a parameter in the Kaelble theory and β₀ being some reference value of the Kaelble parameter. When the curves of F_p ～ v_p and those of G″ ～ ωβ₀ were plotted together, they followed the same trend of variation. This analogy between G″(ωβ₀/β) and F_p(v_p) was further confirmed by the fact that the apparent activation energies of the primary glass transition for G″(ω) and F_p(v_p) are virtually the same, suggesting that the analogy between G″(ω) and F_p(v_p) is dictated by the glass transition. The existence of the above-mentioned analogy between G″(ω) and F_p(v_p) shows that the performance of an adhesive can be evaluated or predicted from the dynamical loss modulus of the corresponding (co)polymer. ©1995 John Wiley & Sons, Inc.     

Evaluation of polymorphisms in repair and detoxification genes in alcohol drinkers and non-drinkers using capillary electrophoresis

Alcohol use disorder (AUD) causes about 3.3 million deaths around the world each year. It is the primary risk factor for the global burden of diseases in American countries. Long-term abuse of alcohol induces numerous molecular and biochemical changes in tissues exposed to alcohol. The toxic effects of alcohol are mediated by DNA damage through various mechanisms, such as induction of oxidative damage, DNA adducts, crosslinks, and DNA strand breaks. The main aim of the current study was to compare the frequency of SNP polymorphisms in XRCC1 (rs7997782) and GSTP1 (rs1695) genes involved in DNA repair of single strand breaks (SSB) and xenobiotic detoxification between alcohol addicts and a control group comprised of non-drinkers. Genetic polymorphisms were identified following allelic specific PCR designed to generate the amplicons containing the variants. Then amplicons were sequenced, and sequences were aligned against the human genome reference deposited in GenBank using the CLC Sequence Viewer software (version 7.6.1). The GG homozygotes in rs1695 (GSTP1) were significantly (p = 0.023) 3.8x more frequent among those with AUD when compared to the control group. No SNP variation was observed in rs7997782 (XRCC1). rs1695 variant has been associated with susceptibility to various diseases, including those related to alcohol consumption.