Tryptophan-containing mutant of human (group IIa) secreted phospholipase A2 has a dramatically increased ability to hydrolyze phosphatidylcholine vesicles and cell membranes

Human nonpancreatic (group IIa) secreted phospholipase A2 (human sPLA2) is associated with a number of inflammatory disorders in which the extracellular concentrations of this enzyme can become highly elevated. It is probable that the enzyme normally acts as an acute-phase protein whose function is to facilitate the removal of infectious organisms or damaged host cells as part of the normal inflammatory response. The enzyme shows negligible activity with phosphatidylcholine (PC) vesicles and cell membranes, presumably reflecting the enzyme's lack of ability to bind productively to such condensed neutral interfaces. Mammalian pancreatic enzymes show modest activity with such interfaces and contain a unique tryptophan at position 3, which is part of the presumptive interfacial binding surface of these enzymes. Human sPLA2 does not contain tryptophan. The amphiphilic indole side chain of tryptophan is noted for its ability to penetrate the lipid interface of membranes, and tryptophan residues appear to be associated with the ability of lipases and phospholipases A2 to bind to and hydrolyze such interfaces. We have investigated in detail the properties of a V3W mutant of human sPLA2, which has a unique tryptophan on the interfacial binding surface of this enzyme. Although this enzyme shows a modest ( approximately 50%) reduction in activity when anionic substrates are used under standard assay conditions, the activity of the enzyme on phosphatidylcholine vesicles and cell membranes is dramatically increased compared with human sPLA2. This is particularly the case with small unilamellar vesicles of PC, where activity is enhanced over 250-fold compared to the almost zero activity expressed by human sPLA2. This enhanced activity is best explained by increased interfacial binding and activation of the V3W mutant and is not due to enhanced active-site binding and hydrolysis. The results highlight the important role that tryptophan residues can play in interfacial binding, particularly to condensed zwitterionic interfaces. The interfacial characteristics of the mutant human enzyme now resemble more closely the mammalian pancreatic enzymes that already have a tryptophan at position 3.     

Polyphenol-rich seaweed (Eucheuma cottonii) extract suppresses breast tumour via hormone modulation and apoptosis induction

The edible red seaweed Eucheuma cottonii is abundantly cultivated for carrageenan production. This study investigated the effects of dietary E. cottonii polyphenol-rich extract (ECME) on breast cancer. In vitro assays showed that ECME was antiproliferative against oestrogen-dependent MCF-7 and oestrogen-independent MB-MDA-231 human breast-cancer cells (IC₅₀ values of 20 and 42 μg/ml, respectively) but was non-toxic to normal cell lines. The ECME (150 and 300 mg/kg BW) was fed to female rats and, after 4 weeks, rat mammary tumour was induced using LA7 cells (inoculated subcutaneously). The ECME inhibited tumour development and erythrocyte lipid peroxidation in the cancer-induced rats, dose-dependently. It showed anti-oestrogenic effects on the rat estrous cycle and serum hormone levels. Electron microscopy and histopathology observations confirmed apoptosis in the rat mammary tumours. The polyphenol-rich ECME was tumour-suppressive via apoptosis induction, downregulating the endogenous oestrogen biosynthesis, and improving antioxidative status in the rats.     

Effects of Enzymatic Liquefaction, Maltodextrin Concentration, and Spray-Dryer Air Inlet Temperature on Pumpkin Powder Characteristics

This study was conducted to investigate the effects of three variables namely cellulase (Celluclast, Novozymes, Denmark) concentration (0–1%, v/w (x ₁)), maltodextrin (MD) concentration (15–30%, w/w (x ₂)), and spray-dryer air inlet temperature (150–190 °C (x ₃)) on pumpkin powder characteristics using enzymatically macerated pumpkin with Pectinex® Ultra SP-L (2.5%, v/w). The powder characteristics considered as response variables in response surface methodology were process yield, moisture content, stickiness, water activity, and hygroscopicity. Results indicated that the response surface models were significantly (p?≤?0.05) fitted for all response variables in the studied independent variables range. The concentration of Celluclast and MD should be considered as critical factors which may increase process yield of pumpkin powder. The effect of Celluclast concentration on pumpkin powder characteristics especially for process yield and stickiness was noticeable. The main effect of MD and quadratic term of Celluclast had the most significant effect on stickiness. Negative interaction value of MD with Celluclast indicated that stickiness decreased when mixture of MD and Celluclast was used and also Celluclast reduced the impact of air inlet temperature on stickiness. The overall optimum region resulted in a desirable powder characteristics was predicted to be obtained by combined level of air inlet temperature 180 °C, Celluclast 0.7% (v/w), and MD 23% (w/w). The theoretical and experimental validation ensuring the adequacy of the response surface models described the changes in physical properties of powder as a function of Celluclast, MD, and air inlet temperature.     

Ergogenic Attributes of Young and Mature Coconut (Cocos nucifera L.) Water Based on Physical Properties,Sugars and Electrolytes Contents

The present work aimed to compare the main ergogenic attributes of two commercialized stages (young and mature) of coconut water (CW) obtained from four coconut varieties. The changes of electrolytes and sugars in CW upon maturation were quantified by inductively coupled plasma mass spectrophotometer and high-performance liquid chromatography, respectively. Based on the electrolyte profiling, potassium yielded the highest amount (ranging from 237.41 to 361.20 mg/100 mL) followed by sodium, magnesium, calcium, iron, manganese, copper, selenium, and zinc across all the maturity stages tested. For sugars, there were lower amounts of fructose and glucose, but a higher amount of sucrose with the maturation of the fruits. In conclusion, the amount of beneficial nutrients in the form of sugars and minerals was higher than that of young CW, and the ergogenic attributes of mature CW especially from MATAG variety (M-MATAG) were the best to be exploited further in the development of natural energy drinks.     

Effect of Te additions on the glass transition and crystallization kinetics of (Sb15As30Se55)100−xTex amorphous solids

Differential scanning calorimetry results under non-isothermal conditions of chalcogenide (Sb₁₅As₃₀Se₅₅)_100?xTe_x (where 0 ≤ x ≤ 10 at.%) glasses are reported and discussed. The dependence of the characteristic temperatures “glass transition temperature (T_g), the crystallization onset temperature (T_c) and the crystallization temperature (T_p)” on the heating rate (β) utilized in the determination of the activation energy for the glass transition (E_g), the activation energy for crystallization (E_c), the glass thermal stability (ΔT = T_c ? T_g) and the Avrami exponent (n). The composition dependence of the T_g, E_g, and E_c were discussed in terms of the chemical bond approach, the average heats of atomization and the cohesive energy (CE). The diffractogram of the transformed material shows the presence of some crystallites of AsSb, Sb₄Te₆, As₂Se₃ and Sb₂Se₃ in the residual amorphous matrix.     

GENOTOXICITY IN CHIRONOMUS KIIENSIS (CHIRONOMIDAE: DIPTERA) AFTER EXPOSURE TO POLLUTED SEDIMENTS FROM RIVERS OF NORTH PENINSULAR MALAYSIA: IMPLICATION FOR ECOTOXICOLOGICAL MONITORING

Rapid industrialization and urbanization has led to increasing input of chemical contaminants into the aquatic environment of Malaysia. Despite the threat civilization poses to the biota, there are still very few relevant studies on ecotoxicological testing of river ecosystems. To overcome this knowledge gap, we examined lethal and genotoxic effects of sediments from different rivers of the northern Malaysia against Chironomus kiiensis, a group well represented in the aquatic fauna of this region. We exposed the larvae to sediments from Selama River (SR), Permatang Rawa River (PRR) and Kilang Ubi River (KUR) at various durations (0, 6, 12, 24 and 48 h). The larval mortality was monitored, whereas DNA damage in survivors' cells was determined using the comet assay. Pollution level indexed by the amounts of heavy metals and other organic contaminants in the sediment showed progressive increases from SR to PRR to KUR. Highly polluted sediments (PRR to KUR) were detrimental to C. kiiensis larvae, most of which did not survive following exposure for long periods. DNA analyses revealed greater damages in nuclei derived from larvae maintained on polluted sediments, in particular, those from KUR. The effects on the genomic material of C. kiiensis larvae occurred in a time‐dependent manner, with damage level increasing as exposure time progressed. Our results highlight the genotoxic properties of polluted sediments. More importantly, this study showed that C. kiiensis larvae could respond to different levels of pollution with respect to exposure time. It is concluded that C. kiiensis larvae is a potential candidate for river ecotoxicological monitoring. Copyright © 2012 John Wiley & Sons, Ltd.     

Improving Rainfall Forecasting Efficiency Using Modified Adaptive Neuro-Fuzzy Inference System (MANFIS)

Rainfall is one of the most complicated effective hydrologic processes in runoff prediction and water management. The adaptive neuro-fuzzy inference system (ANFIS) has been widely used for modeling different kinds of nonlinear systems including rainfall forecasting. Adaptive Neuro-Fuzzy Inference Systems (ANFIS) combines the capabilities of Artificial Neural Networks (ANN) and Fuzzy Inference Systems (FIS) to solve different kinds of problems, especially efficient in rainfall prediction. This paper after reconsidering conventional ANFIS architecture brings up a modified ANFlS (MANFlS) structure developed with attention to making ANFIS technique more efficient regarding to Root Mean Square Error (RMSE), Correlation Coefficient (R ²), Root Mean Absolute Error (RMAE), Signal to Noise Ratio (SNR) and computing epoch. The modified ANFIS (MANFIS) architecture is simpler than conventional ANFIS with nearly the same performance for modeling nonlinear systems. In this study, two scenarios were introduced; in the first scenario, monthly rainfall was used solely as an input in different time delays from the time (t) to the time (t-4) to conventional ANFIS, second scenario used the modified ANFIS to improve the rainfall forecasting efficiency. The result showed that the model based Modified ANFIS performed higher rainfall forecasting accuracy; low errors and lower computational complexity (total number of fitting parameters and convergence epochs) compared with the conventional ANFIS model.     

Benefits valuation of potable water quality improvement in Malaysia: the case of Kajang Municipality

This article estimates the benefits of potable water quality improvements in Kajang Municipality in the state of Selangor, Malaysia, using the avertive cost method. Households were willing to pay MYR 322 annually to improve potable water quality. This represents about 80% of their average annual water bill. The present value of aggregate benefits over a period of 30 years at various social discount rates ranged from MYR 301 million to MYR 768 million. These estimates can be used as a reference for public investment criteria. The findings suggest that there is merit in an upward revision of water tariffs if they provide improvements in water quality.     

Robust control design of power system stabilizers using multivariable frequency domain techniques

H_∞ and structured singular value optimization techniques are used to design robust power system stabilizers (PSS) for a single-machine and a two-machine system with varying operating conditions. Realistic uncertainty models to represent the possible operating conditions as perturbations from a nominal operating condition are developed. System experience is used to select weighting functions to provide adequate damping and shape the controller frequency response. Computer simulations show that the PSS designed using the proposed technique provides improved damping compared to a conventional PSS.