The xanthophyll cycle and sustained thermal energy dissipation activity in Vinca minor and Euonymus kiautschovicus in winter

The influence of low temperature on the operation of the xanthophyll cycle and energy dissipation activity, as ascertained through measurements of chlorophyll fluorescence, was examined in two broad-leaved evergreen species, Vinca minor L. and Euonymus kiautschovicus Loessner. In leaves examined under laboratory conditions, energy dissipation activity developed more slowly at lower leaf temperatures, but the final, steady-state level of such activity was greater at lower temperatures where the rate of energy utilization (through photosynthetic electron transport) was much lower. The rate at which energy dissipation activity increased was similar to that of the de-epoxidation of violaxanthin to antheraxanthin and zea-xanthin at different temperatures. However, leaves in the field examined prior to sunrise on mornings following cold days and nights exhibited a retention of antheraxanthin and zeaxanthin that was associated with sustained decreases in photosystem II efficiency. We therefore suggest that this phenomenon of ‘photoinhibition’ in response to light and cold temperatures during the winter results from sustained photoprotective thermal energy dissipation associated with the xanthophyll cycle. Such retention of the de-epoxidized components of the xanthophyll cycle responded to day-to-day changes in temperature, being greatest on the coldest mornings (when photoprotective energy dissipation might be most required) and less on warmer mornings when photosynthesis could presumably proceed at higher rates.     

Monoamine oxidase-A is an important source of oxidative stress and promotes cardiac dysfunction,apoptosis, and fibrosis in diabetic cardiomyopathy

Oxidative stress is closely associated with the pathophysiology of diabetic cardiomyopathy (DCM). The mitochondrial flavoenzyme monoamine oxidase A (MAO-A) is an important source of oxidative stress in the myocardium. We sought to determine whether MAO-A plays a major role in modulating DCM. Diabetes was induced in Wistar rats by single intraperitoneal injection of streptozotocin (STZ). To investigate the role of MAO-A in the development of pathophysiological features of DCM, hyperglycemic and age-matched control rats were treated with or without the MAO-A-specific inhibitor clorgyline (CLG) at 1 mg/kg/day for 8 weeks. Diabetes upregulated MAO-A activity; elevated markers of oxidative stress such as cardiac lipid peroxidation, superoxide dismutase activity, and UCP3 protein expression; enhanced apoptotic cell death; and increased fibrosis. All these parameters were significantly attenuated by CLG treatment. In addition, treatment with CLG substantially prevented diabetes-induced cardiac contractile dysfunction as evidenced by decreased QRS, QT, and corrected QT intervals, measured by ECG, and LV systolic and LV end-diastolic pressure measured by microtip pressure transducer. These beneficial effects of CLG were seen despite the persistent hyperglycemic and hyperlipidemic environments in STZ-induced experimental diabetes. In summary, this study provides strong evidence that MAO-A is an important source of oxidative stress in the heart and that MAO-A-derived reactive oxygen species contribute to DCM.     

Effect of natural exogenous antioxidants on aging and on neurodegenerative diseases

Abstract

Aging and neurodegenerative diseases share oxidative stress cell damage and depletion of endogenous antioxidants as mechanisms of injury, phenomena that are occurring at different rates in each process. Nevertheless, as the central nervous system (CNS) consists largely of lipids and has a poor catalase activity, a low amount of superoxide dismutase and is rich in iron, its cellular components are damaged easily by overproduction of free radicals in any of these physiological or pathological conditions. Thus, antioxidants are needed to prevent the formation and to oppose the free radicals damage to DNA, lipids, proteins, and other biomolecules. Due to endogenous antioxidant defenses are inadequate to prevent damage completely, different efforts have been undertaken in order to increase the use of natural antioxidants and to develop antioxidants that might ameliorate neural injury by oxidative stress. In this context, natural antioxidants like flavonoids (quercetin, curcumin, luteolin and catechins), magnolol and honokiol are showing to be the efficient inhibitors of the oxidative process and seem to be a better therapeutic option than the traditional ones (vitamins C and E, and β-carotene) in various models of aging and injury in vitro and in vivo conditions. Thus, the goal of the present review is to discuss the molecular basis, mechanisms of action, functions, and targets of flavonoids, magnolol, honokiol and traditional antioxidants with the aim of obtaining better results when they are prescribed on aging and neurodegenerative diseases.     

Numerical Simulations and Long-Column Tests of LNAPL Displacement and Trapping by a Fluctuating Water Table

Long-column laboratory tests were performed to validate improvements to the MOFAT program for simulating LNAPL displacement and entrapment in response to a fluctuating water table. The long-column tests consisted of a fluctuating water table and its subsequent displacement and entrapment of an LNAPL. The modifications of MOFAT include a linear LNAPL trapping estimate and a new scaling technique for the inhibition portion of the fluctuation (water table rise). Improved prediction of the LNAPL trapping was obtained by assuming the amount of LNAPL that is trapped by a rising water table is proportional to the antecedent water content of the porous medium. The pressure-saturation relationship for the air-water drainage system was scaled to estimate the LNAPL-water and air-LNAPL drainage relationships. Scaled inhibition pressure-saturation relationships are improved by incorporating a correction for contact angle hysteresis and surface roughness. The incorporation of these changes into MOFAT led to noticable improvements in the numerical simulation of the experimental data.     

Proteomic Analysis of Specific Proteins in the Root of Salt-Tolerant Barley

Comparative two-dimensional electrophoresis showed six proteins, which were significantly produced in the root of salt-tolerant barley. These proteins were identified as stress/defense-related proteins that do not scavenge reactive oxygen species directly, suggesting that salt-tolerant barley develops not only an antioxidative system, but also physical and biochemical changes to cope with salt stress.     

A Cysteine Endopeptidase (“Dionain”) Is Involved in the Digestive Fluid of Dionaea muscipula (Venus’s Fly-trap)

The carnivorous plant Dionaea muscipula (Venus’s flytrap) secretes proteinases into the digestive fluid to digest prey proteins. In this study, we obtained evidence that the digestive fluid contains a cysteine endopeptidase, presumably belonging to the papain family, through inhibitor studies and partial amino acid sequencing of the major SDS–PAGE band protein. The name “dionain” is proposed for the enzyme.