Anthocyanin content and the activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) and their relationships were determined in the leaves of six lettuce (Lactuca sativa L.) cultivars, exposed for 6 weeks to alternating three different day/night temperatures. Anthocyanin content was found to be highest at 20/13°C, followed by 25/20°C and 30/25°C, showing ac...

Heavy metals are one of the major groups of contaminants in the environment and many of them are toxic even at very low concentration in plants and animals. However, some metals play important roles in the biological function of many enzymes in living organisms. Metals such as zinc, iron, and cooper are important for survival and activity of enzymes in plants, however heavy metals can inhibit e...

This article compares preferred provider organization (PPO) and health maintenance organization (HMO) performance on the utilization of and consumer satisfaction with preventive care. Surveys were conducted of California health plans, employers, and the insured population collected between 1996 and 1999. The authors found that PPOs were less likely than HMOs to cover some types of preventive ca...

Dense flat-sheet membranes were prepared from poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) using the casting solvents chloroform and 1,1,2-trichloroethylene. X-ray diffraction, tapping mode atomic force microscopy (TM-AFM), and contact angle studies were used to characterize the membranes. The surface energy and the solubility parameters of the PPO membranes were determined from the measured co...

This study examined the acute effects of a single dose of an antioxidant (AO; Lactaway® containing pycnogenol) on time to fatigue (TTF). Nine trained cyclists [mean ± SD age 35 ± 10 yrs; body mass 71.6 ± 10.2 kg; VO2 peak 63 ± 11 ml/kg/min] performed on two separate occasions a continuous protocol of 5 min at 50% of peak power output (PPO), 8 min at 70% of PPO, and then cycled to fatigue at 95%...

This article describes three patients with megakaryoblastic leukemia, in whom the blast cells were identified as megakaryoblasts by the platelet peroxidase (PPO) reaction. More than 70% of the blasts in these patients were positive for the PPO reaction. Ultrastructurally, acid phosphatase activity in the megakaryoblasts was detected in the nuclear envelope, the endoplasmic reticulum, and in a f...

Foi realizado um estudo comparativo entre duas metodologias de imobilização do Azul de Meldola (MB), utilizado para diminuir o potencial de oxidação do NADH. O estudo foi realizado no eletrodo de carbono vítreo através da eletropolimerização do pirrol e MB, empregando a técnica de voltametria cíclica e avaliando-se o efeito do número de ciclos para definir a espessura e a estabilidade do filme....

The active component of phosphate solutions, in relation to promoter action on oxidising enzymes, is the PO(4) (''') ion. This is shown by the demonstration of a hyperbolic relationship between per cent production of CO(2) (of Elodea) and pPO(4), the measure of the phosphate ion potential. This is consistent with the rate of respiration as affected by changing pPO(4) through change of total pho...

A series of supramolecular aggregates were prepared using a poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) (PPO-PEO-PPO) block copolymer and β- or α-cyclodextrins (CD). The combination of β-CD and the copolymer yields inclusion complexes (IC) with polypseudorotaxane structures. These are formed by complexation of the PPO blocks with β-CD molecules producing a powder precipitat...

Polyphenol oxidase (PPO) (E.C. 1.14.18.1) also known as phenolase, catechol oxidase, catecholase, monophenol oxidase, o-diphenol oxidase and orthophenolase based on their substrate specificity, is widely distributed in plants and fungi (Mayer, 2006; Kaur et al., 2010; Asha et al., 2011; Pawar and Ingle, 2014). PPOs have been purified and characterized from a wide range of plant species and a va...